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2021-03-01 | The anti-corrosion properties of sol–gel-based hybrid silanol coatings incorporated with span tea leaves extract employed on low carbon steel in saline solution was explored by electrochemical and surface analyses. Hybrid sol–gel matrices were prepared by copolymerizing tetraethyl orthosilicate (TEOS) and 3-aminopropyltriethoxysilane (APTES). Corrosion protective hybrid sol–gel coatings were dip-coated on low carbon steel substrates and sintered to ensure the formation of metallo-siloxane bonds. Inhibition efficiency of 85.66% was achieved with the doping concentration of 75 ppm of water extract into hybrid sol–gel at 30 °C. Polarisation studies demonstrated that the hybrid coatings incorporated with water extract of span tea leaves operate as a mixed-type inhibitor. The Nyquist impedance plots depicted that on increasing the concentration of span tea leaves extract, charge transfer resistance ( R ct ) increased, and double-layer constant phase element (CPE dl ) decreased. A comparison of the corrosion resistance of the coated and uncoated low carbon steel substrates was presented. Electrochemical noise analysis substantiated that the optimum corrosion-resistant coating formulation endured a much lower current noise fluctuation. Moreover, wettability analysis established the hydrophobic nature of the optimum corrosion protective coating. An anti-corrosion formulation based on hybrid silica sol–gel was prepared. i corr values of coated substrates were significantly lower than the uncoated substrate. Aqueous crude extract-doped-(APTES-TEOS)/Fe showed the highest R ct . Improved hydrophobic characteristics of developed coatings. | Enhanced corrosion inhibition of low carbon steel in aqueous sodium chloride employing sol–gel-based hybrid silanol coatings | 10.1007/s10971-021-05474-5 |
2021-03-01 | Some spiders aerially disperse relying on their fine fibres. This behaviour has been known as ‘ballooning’. Observations on the ballooning behaviour of spiders have a long history and have more recently received special attention, yet its underlying physics is still poorly understood. It was traditionally believed that spiders rely on the airflows by atmospheric thermal convection to do ballooning. However, a recent experiment showed that exposure to an electric field alone can induce spiders’ pre-ballooning behaviours (tiptoe and dropping/dangling) and even pulls them upwards in the air. The controversy between explanations of ballooning by aerodynamic flow or the earth’s electric field has long existed. The major obstacle in studying the physics of ballooning is the fact that airflow and electric field are both invisible and our naked eyes can hardly recognise the ballooning silk fibres of spiders. This review explores the theory and evidence for the physical mechanisms of spiders’ ballooning connects them to the behavioural physiology of spiders for ballooning. Knowledge gaps that need to be addressed in future studies are identified. | Aerodynamics and the role of the earth’s electric field in the spiders’ ballooning flight | 10.1007/s00359-021-01474-6 |
2021-03-01 | Herein, we developed a novel effervescence-assisted dual microextraction method, abbreviated as EM-LPSH, using lighter-than-water phosphonium-based ionic liquids (LPILs) and switchable hydrophilic/hydrophobic fatty acids (SHFAs). The EM-LPSH method was utilized for quick enrichment/extraction of polycyclic aromatic hydrocarbons (PAHs) in edible oils. Owing to lower density than water, LPILs used as the first extractant were floated on the upper layer of the aqueous phase, leading to a convenient separation/collection compared with traditional heavier-than-water imidazolium-based ionic liquids. Interestingly, SHFAs play triple functions: a dispersive solvent in the microextraction process, an acidic source in effervescent reaction, and the second extractant in dual microextraction, due to switchability from hydrophilicity to hydrophobicity. Consequently, the integration of LPILs with SHFAs greatly enhanced the extraction efficiency for PAHs owing to the quick dual microextraction process. Some important variables were rigorously optimized using a one-factor-at-a-time approach. Under optimized conditions, the EM-LPSH/HPLC-FLD method provided a wide linear range (0.07~0.63–200 μg kg −1 ), satisfactory recovery (80.12–103.27%), and low limit of detection (0.02–0.19 μg kg −1 ), as well as high intra-day and inter-day precision (0.03–6.55) for six PAHs in edible oils. By using certified reference material in olive oil samples (GBW10162), the recoveries ranged from 97.40 to 98.39%, demonstrating high accuracy and precision. According to the detected levels of PAHs in six unheated and heated oils, their edible safety was evaluated in detail. In short, the newly developed method is simple, convenient, and highly efficient, thereby showing great prospects for application in conventional monitoring of trace-level PAHs in edible oils. | Effervescence-assisted dual microextraction of PAHs in edible oils using lighter-than-water phosphonium-based ionic liquids and switchable hydrophilic/hydrophobic fatty acids | 10.1007/s00216-021-03167-0 |
2021-03-01 | Centrifugal compressors for the fuel cell vehicles often operate near the surge line compared with the turbocharger compressors. Low solidity and half vaned diffusers are recognized as good ways to improve the stability of the centrifugal compressor. The presented work investigated four diffuser configurations (i.e., the vaneless diffuser (VLD), full-height low solidity vaned diffuser (LSVD), hub-side half vaned diffuser (HVD) and shroud-side half vaned diffuser (SVD)) through steady-state and unsteady numerical simulations. The results show that the best performance is achieved by the LSVD, HVD and SVD at the design, surge and choke conditions. The flow rate at the surge operating point of the HVD has decreased by 15.53% compared with the LSVD, and 9.21% compared with the VLD. At near surge operating point, a longitudinal suction side passage vortex is formed on the hub of the LSVD and rotates as circumferential stall cells. A hairpin vortex is formed along the leading edge and is dragged by the main flow along the suction side as a local vortex shedding. The mechanism of the stability improvement by half vaned diffusers is that the tip leakage vortex migrates from the clearance side to the vane mounting side and replenishes the low-momentum zone on the mounting side. The best position where the half vaned diffuser should be mounted is based on the impeller outlet flow conditions, namely, the location of the wake region, where the meridional velocity and relative stagnation pressure is low. | Numerical Investigation of the Centrifugal Compressor Stability Improvement by Half Vaned Low Solidity Diffusers | 10.1007/s11630-021-1318-6 |
2021-03-01 | Background Metaplastic carcinoma is an aggressive, triple-negative breast cancer (TNBC) with differentiation towards squamous, spindle, or mesenchymal cell types. The molecular underpinnings of the histological subtypes are unclear. Our lab discovered a cytoplasmic function of EZH2, a transcriptional repressor, whereby pEZH2 T367 binds to cytoplasmic proteins in TNBC cells and enhances invasion and metastasis. Here, we investigated the expression and subcellular localization of pEZH2 T367 protein in metaplastic carcinomas. Methods Thirty-five metaplastic carcinomas (17 squamous, 10 mesenchymal, and 8 spindle) were evaluated and immunostained with anti-pEZH2 T367. We analyzed staining intensity (score 1–4), subcellular localization (nuclear/cytoplasmic), and localization within the tumor (center/invasive edge). Protein expression of pEZH2 T367-binding partners was measured from a quantitative multiplex proteomics analysis performed in our lab. Results Cytoplasmic pEZH2 T367 was significantly upregulated in squamous (14 of 17, 82%) compared to mesenchymal (4 of 10, 40%) and spindle (2 of 6, 33%) subtypes ( p = 0.011). Twenty-five of 34 (73%) tumors with available tumor–normal interface showed accentuated cytoplasmic pEZH2 T367 at the infiltrative edge. Cytoplasmic pEZH2 T367 was upregulated in 9 of 10 (90%) tumors with lymph node metastasis ( p = 0.05). Bioinformatics analyses identified an EZH2 protein network in metaplastic carcinomas ( p value: < 1.0e−16). Using quantitative proteomics, we found significantly increased expression of cytoplasmic EZH2-binding partners in squamous compared to spindle and mesenchymal subtypes. Conclusions pEZH2 T367 expression and subcellular localization may be useful to distinguish metaplastic carcinoma subtypes. pEZH2 T367 may play a role in the histological diversity and behavior of these tumors. | Subcellular localization of EZH2 phosphorylated at T367 stratifies metaplastic breast carcinoma subtypes | 10.1007/s12282-020-01189-7 |
2021-03-01 | This article presents the design and prototyping of components for a modular multiple-input-multiple-output (MIMO) millimeter-wave radar for space applications. A single radar panel consists of 8 transmitters (TX) and 8 receivers (RX), which can be placed several times on the satellite to realize application-specific radar apertures and hence different cross-range resolutions. The radar chirp signals are generated by SiGe:C BiCMOS direct-digital-synthesizers (DDS) in the frequency range of 1 to 10.5GHz with a chirp repetition rate of < 1μs within each TX and RX. The latter allows for easy interfaces in the MHz range in between the TX/RX units and therefore optimized 2-D sparse antenna arrays with rather large distances in between the TX/RX antennas. Furthermore, this allows for ideally linear frequency modulated continuous-waveforms (FMCW) in conjunction with phase-shift-keying (PSK) radar signals and enables simultaneous operation of all TX when code division multiplex (CDMA) modulation schemes are applied. Comparably low complexity of the TX/RX units has been achieved by applying straightforward frequency plans to signal generation and detection but comes with challenging requirements for the individual active and passive components. Tackled by thin film technology on alumina and the recently developed SiGe and InP semiconductor technologies, which have been further optimized in terms of process maturity and space qualification. Upconversion and downconversion to and from 85 to 94.5GHz are performed by double balanced Gilbert mixers realized with InP double heterojunction bipolar transistor technology (DHBT) and 42-GHz local oscillator signals from SiGe:C BiCMOS VCO synthesizer using phase-locked-loops (PLL). InP DHBT power amplifiers and low-noise amplifiers allow for output power levels of 15dBm and > 30dB gain with noise figure values of 9dB, respectively. The MIMO radar utilizes patch antenna arrays on organic multilayer printed circuit boards (PCB) with 18dBi gain and 18 ∘ half power beamwidth (HPBW). Generation of power supply and control signals, analog-to-digital conversion (ADC), and radar signal processing are provided centrally to each panel. The radar supports detection and tracking of satellites in distances up to 1000m and image generation up to 20m, which is required to support orbital maneuvers like satellite rendezvous and docking for non-cooperative satellites. | A Modular MIMO Millimeter-Wave Imaging Radar System for Space Applications and Its Components | 10.1007/s10762-020-00736-9 |
2021-03-01 | Prosaposin (PSAP) has two forms: a precursor and a secreted form. The secreted form has neurotrophic, myelinotrophic, and myotrophic properties. The precursor form is a precursor protein of saposins A–D. Although the distribution of PSAP in male reproductive organs is well known, its distribution in female reproductive organs, especially in the oviduct, is unclear. Immunoblots and immunohistochemistry of oviducts showed that oviductal tissues contain PSAP proteins, and a significant increase in PSAP was observed in the estrus-metestrus phase compared to the diestrus-proestrus phase in the ampulla. To identify PSAP trafficking in cells, double-immunostaining was performed with antibodies against PSAP in combination with sortilin, mannose 6 phosphate receptor (M6PR), or low-density lipoprotein receptor-related protein 1 (LRP1). PSAP and sortilin double-positive reactions were observed near the nuclei, as well as in the apical portion of microvillous epithelial cells, whereas these reactions were only observed near the nuclei of ciliated epithelial cells. PSAP and M6PR double-positive reactions were observed near the nuclei of microvillous and ciliated epithelial cells. PSAP and M6PR double-positive reactions were also observed in the apical portion of microvillous epithelial cells. PSAP and LRP1 double-positive reactions were observed in the plasma membrane and apical portion of both microvillous and ciliated epithelial cells. Immunoelectron staining revealed PSAP immunoreactive small vesicles with exocytotic features at the apical portion of microvillous epithelial cells. These findings suggest that PSAP is present in the oviductal epithelium and has a pivotal role during pregnancy in providing an optimal environment for gametes and/or sperm in the ampulla. | Prosaposin in the rat oviductal epithelial cells | 10.1007/s00441-020-03339-x |
2021-03-01 | Objective To determine if early discontinuation of antimicrobials in pediatric patients with low risk febrile neutropenia is as effective as continuing therapy before recovery of counts, in an outpatient setting. Methods In an open label, non-inferiority, randomized controlled phase 3 trial at a tertiary cancer center, patients aged 3–18 y, with low risk febrile neutropenia were started on empirical intra-venous antibiotics in an outpatient setting. Randomization was done when the patients became afebrile for at least 24 h; standard arm consisted of oral antibiotics, while antibiotics were stopped in the experimental arm. Enrolled patients were followed for re-appearance of fever and rate of re-admission, until ANC ≥ 500. A pilot feasibility randomized study with similar design preceded this trial. Results From Jan 2017-Dec 2018, 75 patients were randomized: 38 to stoppage arm while 37 patients received oral antibiotics. Baseline characteristics were equally matched. Success rates were 94.6% in the continuation arm vs. 94.7% in the stoppage arm; absolute risk difference was 0.1% (95% CI: −10.0% to +10.3%), thus suggesting that the experimental arm is non-inferior to the standard arm. There was no re-admission on failure in any arm. Conclusions Antimicrobial therapy in low risk afebrile neutropenic patients can be stopped early. This approach can lead to significant cost and resource benefits. | Early Discontinuation versus Continuation of Antimicrobial Therapy in Low Risk Pediatric Cancer Patients with Febrile Neutropenia, Before Recovery of Counts: A Randomized Controlled Trial (DALFEN Study) | 10.1007/s12098-020-03377-x |
2021-03-01 | Background Low carbohydrate diet (LCD) can improve inflammation and obesity and also circadian rhythm disorders can lead to increased inflammation in obese individuals. The purpose of this study is to evaluate the association between adherence of LCD and circadian rhythm mediated by inflammatory markers including transforming growth factor-β (TGF-β), interleukin-1β (IL-1β) and Galectin-3 in overweight and obese women. Methods 304 women affected by overweight and obesity were enrolled. We evaluated LCD scores by Semi-quantitative food frequency questionnaire (FFQ) of 147 items. The morning-evening questionnaire (MEQ) was applied to evaluate the circadian rhythm. Biochemical parameters such as inflammatory markers and anthropometric components were assessed. Results There was a negative significant correlation between adherence of LCD and circadian rhythm status. In other words, as the LCD scores increased, the odds of circadian rhythm disturbance in intermediate group and morning type persons decreased compared to evening type. It was showed that, IL-1β and Galectin-3 in intermediate and morning type groups, destroyed the significance of this relationship and may be considered as mediating markers. Conclusion Adherence of LCD can improve the circadian rhythm by reducing levels of inflammatory markers and may be considered as a treatment for obesity. | Circulating inflammatory markers may mediate the relationship between low carbohydrate diet and circadian rhythm in overweight and obese women | 10.1186/s12905-021-01240-5 |
2021-03-01 | Onion ( Allium cepa L.) is one of the most important bulbous vegetable used in global kitchen. Although it has various important traits but among them the high total soluble solid content (HTSS) of white onion is highly preferred by the industries for processing purpose. Looking into the broader use of the white onion; we utilized a total of 23 polymorphic simple sequence repeats (SSRs) and intron length polymorphic markers (ILPs) to characterize thirty five white onion genotypes for HTSS. Further, we also correlated these DNA fingerprint data with the TSS for identification of HTSS and LTSS lines. The total average numbers of alleles for SSR and ILP locus, heterozygosity (He) and polymorphism information content were found to be 2.4, 0.35 and 0.29 respectively. The UPGMA dendrogram revealed two distinct clusters of genotypes. Based on the TSS and DNA genotype data, our study revealed that Bhima-shweta (LTSS-12.09%, sub-cluster IAa) & WHT-12L-HT-15-Reject-M-7(HTSS- 18.02%, cluster II) are more diverse than the others. Other white onion lines including WHTB-7G-GT-15-SC-M-7 small bulb (HTSS 18.80%), WHT-2B-GT-18-SC-M-7 (HTSS 18.51%), WHTS-4D-GT-18-MC-M-7 (HTSS 18.49%), WHTB-3C-GT-18-MC-M-7 (HTSS 18.27%) and WHTS-11K-Pickle-SC-M-7 (HTSS 17.68%) were identified as superior HTSS lines. These identified diverse HTSS and LTSS lines could be useful for the mapping of HTSS coding genes for the acceleration of molecular breeding of onion through the marker assisted selection (MAS) which could be used by the industries for the larger scale processing of the white onion products required by the global community. | Identification and characterization of white onion (Allium cepa L.) genotypes for high total soluble solid content through molecular markers | 10.1007/s10722-020-01037-9 |
2021-03-01 | Background The chemical quality of drinking water is widely unknown in low-income countries. Objective We conducted an exploratory study in Manhiça district (Mozambique) to evaluate drinking water quality using chemical analyses and cell-based assays. Methods We measured nitrate, fluoride, metals, pesticides, disinfection by-products, and industrial organochlorinated chemicals, and conducted the bioassays Ames test for mutagenicity, micronuclei assay (MN-FACS), ER-CALUX, and antiAR-CALUX in 20 water samples from protected and unprotected sources. Results Nitrate was present in all samples (median 7.5 mg/L). Manganese, cobalt, chromium, aluminium, and barium were present in 90–100% of the samples, with median values of 32, 0.6, 2.0, 61, 250 μg/l, respectively. Manganese was above 50 μg/l (EU guideline) in eight samples. Arsenic, lead, nickel, iron, and selenium median values were below the quantification limit. Antimony, cadmium, copper, mercury, zinc and silver were not present. Trihalomethanes, haloacetic acids, haloacetonitriles and haloketones were present in 5–28% samples at levels ≤4.6 μg/l. DDT, dieldrin, diuron, and pirimiphos-methyl were quantified in 2, 3, 3, and 1 sample, respectively (range 12–60 ng/L). Fluoride was present in one sample (0.11 mg/l). Trichloroethene and tetrachloroethene were not present. Samples were negative in the in vitro assays. Significance Results suggest low exposure to chemicals, mutagenicity, genotoxicity and endocrine disruption through drinking water in Manhiça population. High concentration of manganese in some samples warrants confirmatory studies, given the potential link to impaired neurodevelopment. | Chemical and in vitro bioanalytical assessment of drinking water quality in Manhiça, Mozambique | 10.1038/s41370-020-00282-5 |
2021-03-01 | In this paper, we introduce an estimation of the random Klinkenberg slip coefficient in the apparent permeability model using a chaos decomposition technique. The apparent permeability expression (Klinkenberg model) is used to describe natural gas transport in low-permeability media. In this process, the Klinkenberg factor is considered as a random parameter that depends on two random variables. The mean and variance (or standard deviation) of the two random variables can be estimated from the empirical data available in the literature. Therefore, the variation in the pressure is related directly to the random variation in the Klinkenberg factor. The polynomial chaos expansion is used to decompose the governing equation into a set of coupled deterministic equations that are solved and then used to compute the mean and variance of the solution. The algorithm of how to solve the deterministic coupled system is also presented. For verification, the model and its solution have been compared with the analytical solution of the basic steady-state version of the model. The comparison shows a very good agreement. The effects of a number of important parameters have been presented in graphs and discussed. It was found that the stochastic model works very well with small values of the liquid equivalent permeability, which meets the characteristics of low-permeability reservoirs. Also, the stochastic model works very well with small values of gas viscosity. On the other hand, the porosity seems to be not engaged well with the low-permeability model. The sensitivity of selection of random parameters is also investigated as well as the transient effect. | Stochastic Estimation of the Slip Factor in Apparent Permeability Model of Gas Transport in Porous Media | 10.1007/s11242-021-01575-5 |
2021-03-01 | The toxic effects of heavy metals pose a significant threat to the productivity and stability of forest ecosystems. Changes in the agrochemical properties of polluted forest soils due to global climate changes can increase the bioavailability of previously immobilized heavy metals. To test this hypothesis, we studied the effects of short-term shock exposure to ZnSO 4 (50, 150, 300 μM) or CuSO 4 (2.5, 5, 10 μM) in hydroculture on 4- to 6-week-old seedlings of Scots pine ( Pinus sylvestris L.) with well-developed root systems. The effects of the excess heavy metals on mineral nutrients and the functioning of low-molecular-weight antioxidants and glutathione in protecting plants from oxidative damage were studied. Even short-term exposure to exogenous metals led to their rapid accumulation in the root system and their subsequent transport to aboveground organs. An increase in the 4-hydroxyalkenals content in seedling needles exposed to excess Cu led to an increase in the content of proanthocyanidins and catechins, which act as scavengers of reactive oxygen species. The impact of both metals led to the rapid development of mineral nutrient imbalances in the seedlings, which were most pronounced in the presence of excess Zn. Exposure to excess Zn led to a disruption in the translocation of Fe and a decrease in the Fe content in the needles. The most dramatic consequence of Zn exposure was the development of Mn deficiency in the roots, which was the likely cause of the inhibition of phenolic compound synthesis. A deficiency in phenolic compounds can have serious environmental consequences for pine populations that are at risk of contamination by Zn and Cu salts. | Phytotoxicity of short-term exposure to excess zinc or copper in Scots pine seedlings in relation to growth, water status, nutrient balance, and antioxidative activity | 10.1007/s11356-020-11723-x |
2021-03-01 | Besides Quercus , Acer L. genus is the largest tree genus in the Northern Hemisphere and consists of about 124–156 species. High morphological and molecular variability has led to infra-specific complexity within most species of this genus. In Iran, the Acer cappadocicum subsp. cappadocicum Gled. is distributed in eastern to western parts of the Hyrcanian forests. In this study, three leaf-morphotypes in A. cappadocicum Gled. were identified during sampling in a forest located in the Hyrcanian region, leading to obscuring taxonomic situations of this taxon. Against this backdrop, the present study was performed to clarify intraspecific situation of this valuable tree using both macro-/micromorphological and molecular approaches. Forty-five plant samples of A. cappadocicum were randomly selected within nine geographical regions of four provinces in Hyrcanian forests of Iran. Internal transcribed spacer (ITS) (for eight individuals) and inter-simple sequence repeat (ISSR) molecular markers (for 45 individuals) were used along with the epidermal scanning electron micrograph (SEM) of the leaf epidermis. Considering the obtained results, acceptance of the expected lower taxa in A. cappadocicum ssp. cappadocicum in north of Iran could not be supported by molecular evidence. Results of the study indicated no correlation between variations in leaf-morphology, ISSRs, and ITS. However, there are two main clusters in ITS tree without discrete morphological characters showing differentiation and variability in ITS region within this species. This subspecies was compared also with other subspecies. | Infra-specific variation of Acer cappadocicum (Sapindaceae): morphological and molecular approaches | 10.1007/s40415-020-00692-7 |
2021-03-01 | The design of most cities prioritizes the use of motorized vehicles, having a negative effect on urban health. A major concern in the European Union (EU) is air pollution, especially nitrogen dioxide (NO 2 ), which causes many inhabitants health problems and decreases the quality of life. A non-expensive way to reduce pollutants is implementing road restriction policies, as the creation of low emission zones. In this work, we analyze the case of Madrid Central, a low emission zone deployed in Madrid, Spain. We evaluate if it was effective to reduce air pollutants and if there were a side effect, as pollution displacement, during its application. Drawing on open data, we analyze air quality at different points of the city, before and during the application of this measure. Taking into account the EU directives in terms of what healthy air means, we consider three metrics: (a) the trend of NO 2 concentration in the air in both periods, (b) the difference between the NO 2 concentration during both periods, and (c) the percentage of time in which the population is exposed to air with NO 2 concentration under a specific threshold (healthy air as defined by the EU). According to the results, Madrid Central significantly reduces the NO 2 concentration in the air and does not produce pollution displacement. Thus, the population breathes healthy air during more time, and there is a positive effect on the whole city. | Car restriction policies for better urban health: a low emission zone in Madrid, Spain | 10.1007/s11869-020-00938-z |
2021-03-01 | Purpose Pediatric low-grade gliomas (pLGGs), the most frequent pediatric brain tumors, include different entities harboring distinct histological and molecular features. A major limitation in the development of treatments for these tumors is the absence of reliable in vitro models that would allow a better understanding of the molecular mechanisms that support their growth. Surgical excision is the primary treatment method and the extent of resection represents one of the strongest prognostic factors. pLGGs that cannot be completely resected are prone to recur and associated with relapses and extensive morbidities, thus remaining a major clinical challenge. Methods We established a protocol to successfully derive primary patient-derived pLGG cells and to fully characterize them from a molecular point of view. Results Primary patients-derived pLGG cells were extensively analyzed in order to confirm their reliability as cellular models. Specifically, we evaluated the growth rate, senescence, and molecular features, such as BRAF mutational status, methylation, and protein expression profile. Conclusion This study extensively describes pLGG primary cellular models in terms of isolation, culture method, and molecular characterization that can be used to investigate pLGG biology. | Pediatric low-grade gliomas: molecular characterization of patient-derived cellular models | 10.1007/s00381-020-04559-w |
2021-03-01 | Objective Middle cluneal nerve entrapment (MCN-E) around the sacroiliac joint can elicit low back pain (LBP). Pain control can be obtained with anesthetic nerve blocks; however, when their effectiveness is transient, surgical release may be necessary. We investigated the efficacy of radiofrequency thermocoagulation (RFTC) in patients with MCN-E. Methods Between December 2018 and August 2019, 11 consecutive patients (4 men, 7 women; mean age 76.4 years) with intractable medial buttock pain due to MCN-E underwent MCN RFTC. The mean symptom duration was 49.5 months; pre-RFTC local MCN blocks provided pain relief for a mean of 7.7 days. The severity of pain in the medial buttock due to MCN-E was recorded before and 2, 6, 12, and 24 weeks after RFTC on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ). Results All patients reported pain alleviation; there were no complications. While there was a significant difference in the pre- and post-RFTC treatment NRS ( p < 0.05), the RDQ scores were significantly lower only after 12 weeks. The duration of pain relief was significantly prolonged by RFTC ( p < 0.05). Two patients suffered pain relapse 10 weeks post-RFTC; pain alleviation was obtained by re-RFTC performed 2 weeks after pain recurrence. Two other patients relapsed 20 and 21 weeks post-RFTC; their symptoms also disappeared by MCN block administered 24 weeks after they had undergone RFTC. Conclusion RFTC may safely control intractable LBP due to MCN-E. | High-frequency thermal coagulation to treat middle cluneal nerve entrapment neuropathy | 10.1007/s00701-020-04404-8 |
2021-03-01 | Abstract— Electrodynamic characteristics of a low-pressure (electron collision frequency much lower than the field frequency) capacitive HF discharge maintained by an electromagnetic field with a frequency between 13 and 900 MHz are studied analytically and numerically. It is demonstrated that the field of both the fundamental mode (the field in the metal–space-charge sheath–plasma–space-charge sheath–metal structure) and the field of the higher-order evanescent modes must be taken into account for correct calculation of discharge characteristics under such conditions in a wide range of electron densities. Expressions governing the amplitudes of excited waves, along with expressions governing the discharge impedance in the presence of these waves, are derived by using field expansion in eigenwaves of an empty waveguide and eigenmodes of the three-layer structure. The case in which the size of plasma is smaller than the size of the electrodes is analyzed in detail. In this case, excitation of higher-order types of waves in the plasma column is generated by axial plasma inhomogeneity and is not related to electrodynamic effects near the electrode boundaries. It is demonstrated that the positions of current and voltage resonances related to propagation of surface waves along the three-layer structure becomes substantially modified due to excitation of higher-order field modes of the same structure. In addition, resonances caused by excitation of standing surface waves near the lateral surface (resonances of higher-order modes of the three-layer structure and an empty waveguide) can take place. Variation of relative position of resonances caused by changes in the discharge chamber geometry is investigated. Obtained results qualitatively agree with the results of numerical calculation of the discharge impedance and field propagation in the discharge by COMSOL Multiphysics ® software package. | Specificities of Electromagnetic Field Excitation in a Capacitive HF Discharge. III. Symmetric Discharge Partially Filling the Discharge Chamber | 10.1134/S1063780X2102001X |
2021-03-01 | Aim The risk of excessive bleeding prompts physicians to discontinue aspirin in patients on low-dose, long-term therapy which in turn puts them at the risk from adverse cardiovascular and thrombotic events. Effect of low-dose aspirin therapy on platelet function was assessed using platelet aggregation method. The aim was to correlate the laboratory platelet function with cutaneous and clinical oral bleeding time (BT). Materials and Methods One hundred one patients were enrolled in this prospective trial and were allocated into two groups. Interventional or test group consisted of patients who were on aspirin therapy (75 mg/100 mg) for primary or secondary prevention of angina, myocardial infarction and stroke. Minor oral surgical procedure was performed in this group without discontinuing aspirin therapy. Control group consisted of healthy patients (under no medication) undergoing minor oral surgical procedure. Cutaneous and clinical oral BT were recorded in both the groups. Venous blood sample was drawn, and percentage platelet aggregation function was analysed using adenosine diphosphate (ADP) and arachidonic acid (AA) reagents. The percentage of platelet aggregation was then correlated with cutaneous and clinical oral BT. Results A significant decrease in percentage platelet aggregation using ADP (aspirin-74.7 21.39; control-89.2 13.70) and AA (aspirin-47.6 23.11; control-82.3 20.17) was observed. However, there were no significant difference in mean cutaneous BT (aspirin-1.5 0.65 min; control-1.6 0.71 min) and clinical oral BT (aspirin-5.0 2.48 min; control-4.8 2.60 min) in aspirin and control groups. Conclusion Majority of the minor oral surgical procedures can be carried out safely without discontinuing aspirin in patients on low-dose long-term therapy. This is possible because despite significant platelet aggregation evident in laboratory evaluation there is lack of its clinical corroboration owing to aspirin resistance. Clinical Trial Registration CTRI/2018/02/012055. | Clinical Post-operative Bleeding During Minor Oral Surgical Procedure and In Vitro Platelet Aggregation in Patients on Aspirin Therapy: Are they Coherent? | 10.1007/s12663-020-01438-4 |
2021-03-01 | Abstract — The water exchange between the Black Sea and the Azov Sea is investigated on the base of the marine observations aboard the R/V Deneb in 2018 and 2019. The surveys were conducted under different weather conditions, which led to large variability of the results. The northern wind contributes to the formation of water transfer to the south, which exceeds by five to six times the water transfer to the north; the southern wind leads to filling of the entire cross-section, 17 km wide, with waters flowing northward and a volume up to 30 times higher than the average flow rate of the Don River for the modern low-water period. In this study, the water circulation patterns of the Azov Sea on the surface and in the bottom layers were constructed, confirming the drift scheme of water movement. Inflows of Black Sea water to Temryuk Bay are described in detail. The classification of types of water stratification in Temryuk Bay was based on data from the Southern Scientific Center, Russian Academy of Sciences; four types have been distinguished, and restructuring of the types of stratification in relation to the sea salinization is observed. | Currents of the Azov Sea during the Don River Low-Water Period | 10.1134/S0001437021020132 |
2021-03-01 | This paper presents the construction of prediction intervals (PIs) associated with the Emotional Artificial Neural Network (EANN) via the Lower Upper Bound Estimation method (LUBE) and the classic Bootstrap method for the Suspended Sediment Load (SSL) modeling. As point prediction conveys no information about modeling reliability, PIs were applied. The constructed PIs via the EANN were also compared to those of the classic feed-forward Neural Network (FFNN) model. It was attempted to construct the PIs of the SSL modeling in both daily and monthly scales for two watersheds, Upper Rio Grande River, in the United States and the Lighvanchai River in Iran. The PIs were quantified via coverage and width criteria. In the LUBE method, Genetic Algorithm (GA) constructed the PIs by minimizing the cost function of Combinational coverage Width-based Criterion (CWC). Comparison of the results indicated that the criterion of the CWC for PIs of EANN was up to 72% and 78% lower than that to the PIs of the FFNN, respectively, in the LUBE and Bootstrap methods, which showed the reliability of the EANN. In addition, obtained results via the LUBE and the Bootstrap techniques denoted the lower level of uncertainty of the LUBE method. Comparing the CWC criterion of both methods indicated that for the LUBE method, CWC was up to 39% lower than that for the Bootstrap method. Also, the PIs of the FFNN for the Lighvanchai river modeling showed reliable results with CWC of 56% lower than Upper Rio Grande River, but PIs of the EANN led to lower level of uncertainty in Upper Rio Grande River modeling. | Assessing the effect of emotional unit of emotional ANN (EANN) in estimation of the prediction intervals of suspended sediment load modeling | 10.1007/s12145-020-00567-1 |
2021-02-24 | Background Pain hypersensitivity can be assessed using Quantitative Sensory Testing (QST) and is associated with persistent low back pain. Spinal manipulation appears to modify pain hypersensitivity, and this could function as one mechanism leading to clinical improvements. In the current study, we applied a comprehensive QST battery to assess pain sensitivity in a cohort of low back pain patients before and after spinal manipulation to improve our understanding of the association between QST and clinical improvements. This study addresses two questions: Are clinical improvements following spinal manipulation in low back pain patients contingent on pain hypersensitivity, and does pain sensitivity change following spinal manipulation? Methods We performed a secondary analysis of data from a randomized clinical trial. One hundred and thirty-two participants with persistent LBP were treated with spinal manipulation four times over two weeks. Patient-reported outcomes and QST were assessed at baseline, after the fourth spinal manipulation session, and 14-days later. The clinical outcomes were changes in low back pain intensity and disability. Using latent profile analysis, we categorized the participants into clusters depending on their baseline QST scores. We used linear mixed models to examine the association between clusters and changes in patient-reported outcomes and QST. Results Two clusters emerged: a Sensitized and a Not sensitized . The former had significantly lower regional pressure and thermal pain thresholds, remote pressure pain tolerance, and lower inhibitory conditioned pain modulation than the Not sensitized group. However, we only found between-cluster differences for regional pressure pain threshold following spinal manipulation. Thus, the clusters were not associated with patient-reported pain and disability changes or the remaining QST outcomes. Conclusions We report that the baseline QST profile was not associated with clinical improvements following spinal manipulation. We did observe a substantial change for regional pressure pain threshold, which suggests that any effect of spinal manipulation on pain sensitivity is most likely to be observed as changes in regional, mechanical pain threshold. However, the mechanism that invokes clinical improvement and pain sensitivity changes appear distinct. Due to methodological caveats, we advise caution when interpreting the results. Trial registration Clinical.Trial.gov identifier: NCT04086667 , registered 11 September 2019 – Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04086667 | Spinal manipulation and modulation of pain sensitivity in persistent low back pain: a secondary cluster analysis of a randomized trial | 10.1186/s12998-021-00367-4 |
2021-02-24 | This paper proposes a comparison of the numerical aspect and efficiency of several low rank approximation techniques for multidimensional data, namely CPD, HOSVD, TT-SVD, RPOD, QTT-SVD and HT. This approach is different from the numerous papers that compare the theoretical aspects of these methods or propose efficient implementation of a single technique. Here, after a brief presentation of the studied methods, they are tested in practical conditions in order to draw hindsight at which one should be preferred. Synthetic data provides sufficient evidence for dismissing CPD, T-HOSVD and RPOD. Then, three examples from mechanics provide data for realistic application of TT-SVD and ST-HOSVD. The obtained low rank approximation provides different levels of compression and accuracy depending on how separable the data is. In all cases, the data layout has significant influence on the analysis of modes and computing time while remaining similarly efficient at compressing information. Both methods provide satisfactory compression, from 0.1% to 20% of the original size within a few percent error in $$L^2$$ L 2 norm. ST-HOSVD provides an orthonormal basis while TT-SVD doesn’t. QTT is performing well only when one dimension is very large. A final experiment is applied to an order 7 tensor with $$(4 \times 8\times 8\times 64\times 64\times 64\times 64)$$ ( 4 × 8 × 8 × 64 × 64 × 64 × 64 ) entries (32 GB) from complex multi-physics experiment. In that case, only HT provides actual compression (50%) due to the low separability of this data. However, it is better suited for higher order d . Finally, these numerical tests have been performed with pydecomp , an open source python library developed by the author. | Numerical Study of Low Rank Approximation Methods for Mechanics Data and Its Analysis | 10.1007/s10915-021-01421-2 |
2021-02-22 | Storing bio-specimens in adequate temperatures is an important task in hospitals. Usually an assigned employee records manually the temperatures of the hospital cold storages such as refrigerators and freezers that keep them at regular intervals. In this research, a low power wireless Bluetooth Low Energy network is applied where the central monitoring personal computer, receives the temperature data and stores in a database. The system consists of many beacons which are wirelessly sending the measured temperature data, and the central monitoring computer which allows the user to monitor that data. In the case of wireless signals getting blocked due to obstacles, repeaters called bridges send the data to the central computer forming a so-called scatter net. Once the data is received by the Bluetooth module connected to the monitoring computer, an application saves the data into a database. This web application forms a website where the users holding the authentication information can log in and monitor the temperature data in the form of tables and graphs. The same information can be viewed by a smartphone and a person in charge receives a warning SMS message. This system also provides a scheduled backup system where the database is automatically backed up periodically. The suggested system has the advantage of managing reagent records with reduced manpower whilst coping for emergency situations automatically. | Development of Temperature Monitoring System of Hospital Cold Storages Based on Wireless Network and its Database Management | 10.1007/s10916-021-01711-0 |
2021-02-18 | In this paper, an extensive investigation of low-frequency (1/ f ) noise and total ionizing dose–response of junctionless accumulation mode double-gate (JAM DG) MOSFET is presented. Current–voltage ( I d – V g ) characteristics and low-frequency noise of JAM DG MOSFET are simulated at different ionized doses and compared to different gate oxide thickness and different channel doping concentrations. A significant amount of irradiation-induced threshold voltage shift and increase in low-frequency noise is observed for different gate oxide thickness and channel doping concentration. Moreover, the irradiation-induced border trap densities are also obtained at different doses. The gamma radiation model of Sentaurus TCAD is used to get the required results. | Total ionizing dose effects in junctionless accumulation mode MOSFET | 10.1007/s00339-021-04313-2 |
2021-02-18 | Background The effect of low-level laser therapy (LLLT) on pain mitigation following the third molar surgery is still controversial. The absence of a standard method for using laser among the studies is related to the types of sample selection, sample size, control, and LLLT parameters, which make pain mitigation following surgery more controversial. Therefore, this study aimed to determine the effect of LLLT on reducing pain, swelling, and trismus following the mandibular impacted third molar surgery. Methods This study was performed on 25 healthy subjects. After the surgery, amoxicillin 500 mg was prescribed every 8 h for a 7-day period besides oral Ibuprofen (Gelofen) 400 mg every 12 h for a 3-day period. The intraoral Laser diode 940 nm was applied immediately after suture on the tested side, while on the placebo side, a fiber tip was used with no laser radiation following surgery. Eventually, the pain score was evaluated by VAS index from the 1st to the 7th-day post-surgery and then analyzed by SPSS 24. Results The results indicate that the mean swelling and trismus before, during, 2 days after, and 7 days after the intervention did not differ significantly between the two studied groups. However, the results show that on the sixth and seventh days, the pain was significantly lower in the intervention group compared to the control group. Conclusions The results suggest that although the pain, swelling, and trismus following surgery were lower on the radiated side, only pain was found to be significant on the radiated side ( p < 0.05). The registration number of the clinical trial in a Primary Registry in the WHO Registry Network is IRCT20141209020258N110 and the date of retrospective registration is 04/05/2019. The related URL is https://www.irct.ir/trial/36321 . | Low‐level laser therapy using laser diode 940 nm in the mandibular impacted third molar surgery: double-blind randomized clinical trial | 10.1186/s12903-021-01434-1 |
2021-02-16 | We investigate the action of discretized Virasoro generators, built out of generators of the lattice Temperley-Lieb algebra (“Koo-Saleur generators” [1]), in the critical XXZ quantum spin chain. We explore the structure of the continuum-limit Virasoro modules at generic central charge for the XXZ vertex model, paralleling [2] for the loop model. We find again indecomposable modules, but this time not logarithmic ones. The limit of the Temperley-Lieb modules W j, 1 for j ≠ 0 contains pairs of “conjugate states” with conformal weights ( h r,s , h r,−s ) and ( h r,−s , h r,s ) that give rise to dual structures: Verma or co-Verma modules. The limit of W 0 , q ± 2 $$ {W}_{0,{\mathfrak{q}}^{\pm 2}} $$ contains diagonal fields ( h r, 1 , h r, 1 ) and gives rise to either only Verma or only co-Verma modules, depending on the sign of the exponent in q ± 2 $$ {\mathfrak{q}}^{\pm 2} $$ . In order to obtain matrix elements of Koo-Saleur generators at large system size N we use Bethe ansatz and Quantum Inverse Scattering methods, computing the form factors for relevant combinations of three neighbouring spin operators. Relations between form factors ensure that the above duality exists already at the lattice level. We also study in which sense Koo-Saleur generators converge to Virasoro generators. We consider convergence in the weak sense, investigating whether the commutator of limits is the same as the limit of the commutator? We find that it coincides only up to the central term. As a side result we compute the ground-state expectation value of two neighbouring Temperley-Lieb generators in the XXZ spin chain. | The action of the Virasoro algebra in quantum spin chains. Part I. The non-rational case | 10.1007/JHEP02(2021)130 |
2021-02-15 | The combination of low clinker high-performance concrete (LCHPC) and ultra-high modulus (UHM) carbon fibre reinforced polymer (CFRP) tendons was recently proposed for prestressed structural elements. The 70% reduction in cement content resulting in limited creep and shrinkage of the LCHPC in comparison to a conventional high-performance concrete (HPC) and the very high UHM-CFRP tendon stiffness (> 509 GPa) were expected to impact the mechanical behaviour of such structures. This study focuses on the behaviour of 3 m-long beam specimens during prestressing, concrete hardening and in 4 point-bending experiments. Fibre optic sensors were implemented inside the CFRP tendons to measure strain during those stages and a digital image correlation system was employed to monitor the 4-point-bending tests. After 28 days, the LCHPC recipe, despite a 70% cement reduction and much smaller environmental footprint, did not show measurable differences in the prestress loss behaviour in comparison to a conventional HPC. The UHM-CFRP prestressing tendons, because of their stiffness, showed both higher prestress losses of around 40% and on average a nearly doubled prestress transfer length. However, they increased the beam`s maximum load-bearing capacity by 21% and showed 47% less deflection at failure in comparison to beams prestressed with the standard modulus (UTS)-CFRP tendons. | Prestressing low clinker structural concrete elements by ultra-high modulus carbon fibre reinforced polymer tendons | 10.1617/s11527-021-01634-9 |
2021-02-12 | Magnetic Resonance Imaging (MRI), a non-invasive method for the diagnosis of diverse health conditions has experienced growing popularity over other imaging modalities like ultrasound and Computer Tomography. Initially, proof-of-concept and earlier MRI systems were based on resistive and permanent magnet technology. However, superconducting magnets have long held monopoly of the market for MRI systems with their high-field (HF) strength capability, although they present high construction, installation, and siting requirements. Such stringent prerequisites restrict their availability and use in low-middle income countries. Resistive coil-based magnet, albeit low-field (LF) in capacity, represent a plausible boost for the availability and use of MRI systems in resource constrained settings. These systems are characterized by low costs coupled with substantial image quality for diagnosis of some conditions such as hydrocephalus common is such regions. However, the nature of resistive coils causes them to heat up during operation, thus necessitating a dedicated cooling system to improve image quality and enhance system longevity. This paper explores a range of cooling methods as have been applied to resistive magnets, citing their pros and cons and areas for improvement. | Approaches in cooling of resistive coil-based low-field Magnetic Resonance Imaging (MRI) systems for application in low resource settings | 10.1186/s42490-021-00048-6 |
2021-02-12 | Background Low dose methotrexate toxicity rarely occurs, but may present with severe complications, such as pancytopenia, hepatotoxicity, mucositis, and pneumonitis. Known risk factors for methotrexate toxicity include dosing errors, metabolic syndrome, hypoalbuminemia, renal dysfunction, lack of folate supplementation, and the concomitant use of drugs that interfere with methotrexate metabolism. Vitamin B12 deficiency leads to megaloblastic anemia and may cause pancytopenia, but its role in methotrexate toxicity has not been described. Case presentation We present a case of a patient with rheumatoid arthritis who was admitted with febrile neutropenia, pancytopenia, and severe mucositis, likely secondary to low dose methotrexate toxicity. She had multiple factors that potentially contributed to the development of toxicity, including concurrent sulfasalazine use for rheumatoid arthritis. An evaluation of the patient’s macrocytic anemia revealed pernicious anemia. The patient’s illness resolved with cessation of methotrexate and sulfasalazine, leucovorin treatment and vitamin B12 repletion. Conclusions This case illustrates the multiple factors that may potentially contribute to low dose methotrexate toxicity and highlights the importance of testing for vitamin B12 deficiency in rheumatoid arthritis patients with macrocytic anemia. Addressing all the modifiable factors that potentially contribute to low dose methotrexate toxicity may improve outcomes. | Potential contributors to low dose methotrexate toxicity in a patient with rheumatoid arthritis and pernicious anemia: case report | 10.1186/s41927-020-00175-y |
2021-02-12 | Background Malaria remains a serious health threat in the Amazonas Region of Peru and approximately 95% of the cases, mainly Plasmodium vivax , are found in native communities of The Rio Santiago District, Condorcanqui Province. In 2019, more than one thousand malaria cases were reported, with an unusual number of Plasmodium falciparum autochthonous cases. The present study aims to report this P. falciparum outbreak while describing the epidemiology of malaria and the risk factors associated in the native communities of Amazonas, Peru. Methods The DIRESA-Amazonas in collaboration with the Condorcanqui Health Network and the Institute of Tropical Diseases of the UNTRM carried out a malaria Active Case Detection (ACD III) between January 31st and February 10th of 2020. A total of 2718 (47.4%) individuals from 21 native communities grouped in eight sanitary districts, were screened for malaria infections. Each participant was screened for malaria using microscopy. Follow-up surveys were conducted for all malaria positive individuals to collect socio-demographic data. Spatial clustering of infection risk was calculated using a generalized linear model (GLM). Analysis of risk considered factors such as gender, age, type of infection, symptomatology, and parasitaemia. Results The study suggests that the P. falciparum index case was imported from Loreto and later spread to other communities of Rio Santiago during 2019. The ACD III reported 220 (8.1%) malaria cases, 46 P. falciparum , 168 P. vivax and 6 mixed infections. SaTScan analysis detected a cluster of high infection risk in Middle Rio Santiago and a particular high P. falciparum infection risk cluster in Upper Rio Santiago. Interestingly, the evaluation of different risk factors showed significant associations between low parasitaemia and P. falciparum asymptomatic cases. Conclusion This is the first report of a P. falciparum outbreak in native communities of Condorcanqui, Amazonas. Timely identification and treatment of symptomatic and asymptomatic cases are critical to achieve malaria control and possible elimination in this area. However, the current malaria situation in Condorcanqui is uncertain, given that malaria ACD activities have been postponed due to COVID-19. | Plasmodium falciparum outbreak in native communities of Condorcanqui, Amazonas, Perú | 10.1186/s12936-021-03608-2 |
2021-02-05 | Background Birth asphyxia is one of the leading causes of intrapartum stillbirth and neonatal mortality worldwide. We sought to explore the experiences of health care workers in managing foetal distress and birth asphyxia to gain an understanding of the challenges in a low-income setting. Methods We conducted in-depth interviews with 12 midwives and 4 doctors working in maternity units from different health facilities in Northern Uganda in 2018. We used a semi-structured interview guide which included questions related to; health care workers’ experiences of maternity care, care for foetal distress and birth asphyxia, views on possible preventive actions and perspectives of the community. Audio recorded interviews were transcribed verbatim and analysed using inductive content analysis. Results Four categories emerged: (i) Understanding of and actions for foetal distress and birth asphyxia including knowledge, misconception and interventions; (ii) Challenges of managing foetal distress and birth asphyxia such as complexities of the referral system, refusal of referral, lack of equipment, and human resource problems, (iii) Expectations and blame from the community, and finally (iv) Health care worker’ insights into prevention of foetal distress and birth asphyxia. Conclusion Health care workers described management of foetal distress and birth asphyxia as complex and challenging. Thus, guidelines to manage foetal distress and birth asphyxia that are specifically tailored to the different levels of health facilities to ensure high quality of care and reduction of need for referral are called for. Innovative ways to operationalise transportation for referral and community dialogues could lead to improved birth experiences and outcomes. | Health care workers’ experiences of managing foetal distress and birth asphyxia at health facilities in Northern Uganda | 10.1186/s12978-021-01083-1 |
2021-02-04 | The low pyrolysis-crystallization temperature of 200 °C was firstly reported to prepare crystalline low-selenium Sb 2 S x Se y ( x : y = 3.0:0.2) thin films using the mixture solution of Sb 2 O 3 , Se, CS 2 , and n -butylamine in DMF as a precursor solution. The corresponding thin film solar cells with the architecture of FTO/compact TiO 2 /Sb 2 S x Se y / spiro -OMeTAD/Au achieved a power conversion efficiency of 5.54%, along with an open-circuit voltage of 0.56 V, a short-circuit photocurrent density of 16.16 mA cm −2 and a fill factor of 0.61. The low-temperature preparation process of crystalline Sb 2 S x Se y thin films can provide a feasible approach for assembling the flexible Sb 2 S x Se y thin film solar cells. Graphical abstract | The low-temperature preparation for low-selenium Sb2SxSey thin film solar cells with efficiency of > 5% | 10.1007/s11051-021-05155-y |
2021-02-03 | We study some general properties of coupled quantum systems. We consider simple interactions between two copies of identical Hamiltonians such as the SYK model, Pauli spin chains with random magnetic field and harmonic oscillators. Such couplings make the ground states close to the thermofield double states of the uncoupled Hamiltonians. For the coupled SYK model, we push the numerical computation further towards the thermodynamic limit so that an extrapolation in the size of the system is possible. We find good agreement between the extrapolated numerical result and the analytic result in the large- q limit. We also consider the coupled gauged matrix model and vector model, and argue that the deconfinement is associated with the loss of the entanglement, similarly to the previous observation for the coupled SYK model. The understanding of the microscopic mechanism of the confinement/deconfinement transition enables us to estimate the quantum entanglement precisely, and backs up the dual gravity interpretation which relates the deconfinement to the disappearance of the wormhole. Our results demonstrate the importance of the entanglement between the color degrees of freedom in the emergence of the bulk geometry from quantum field theory via holography. | Entanglement and confinement in coupled quantum systems | 10.1007/JHEP02(2021)034 |
2021-02-03 | In the present paper, we study the combined incompressible and fast rotation limits for the full Navier–Stokes–Fourier system with Coriolis, centrifugal and gravitational forces, in the regime of small Mach, Froude and Rossby numbers and for general ill-prepared initial data. We consider both the isotropic scaling (where all the numbers have the same order of magnitude) and the multiscale case (where some effect is predominant with respect to the others). In the case when the Mach number is of higher order than the Rossby number, we prove that the limit dynamics is described by an incompressible Oberbeck–Boussinesq system, where the velocity field is horizontal (according to the Taylor–Proudman theorem), but vertical effects on the temperature equation are not negligible. Instead, when the Mach and Rossby numbers have the same order of magnitude, and in the absence of the centrifugal force, we show convergence to a quasi-geostrophic equation for a stream function of the limit velocity field, coupled with a transport-diffusion equation for a new unknown, which links the target density and temperature profiles. The proof of the convergence is based on a compensated compactness argument. The key point is to identify some compactness properties hidden in the system of acoustic-Poincaré waves. Compared to previous results, our method enables first of all to treat the whole range of parameters in the multiscale problem, and also to consider a low Froude number regime with the somehow critical choice $$Fr\,=\,\sqrt{Ma}$$ F r = Ma , where Ma is the Mach number. This allows us to capture some (low) stratification effects in the limit. | A Multiscale Problem for Viscous Heat-Conducting Fluids in Fast Rotation | 10.1007/s00332-021-09677-6 |
2021-02-01 | This article studies the cold shock resistance and safety performance of NaNO 3 /SiO 2 /C composite inorganic phase-change thermal storage materials at extremely low temperatures. A low-temperature cold shock test system is built, and the composite inorganic phase-change thermal storage materials of different raw material particle sizes are carried out through the static cold shock and dynamic cold shock at − 40, − 60, − 80 and − 196 °C. The changes in quality, volume, surface morphology phase and thermal properties of the phase-change thermal storage materials are respectively analyzed by means of characterization methods such as scale, vernier caliper, DSC, SEM, and XRD. The results show that the thermal performance of phase-change thermal storage materials with different particle sizes is only 1.97-8.89%, especially under cryogenic shock at − 196 °C. The cold shock resistance is better with the increase in particle size. The physical properties, chemical properties and thermal storage capacity of the material under impact are basically stable, and it has good cold shock resistance. The cold shock of the two methods does not affect the thermal storage function of the material and does not cause thermal energy waste, and the safety performance is better. | Research on Performance and Safety of Composite Inorganic Phase-Change Materials (NaNO3/SiO2/C) under Low-temperature Cold Shock | 10.1007/s11665-020-05343-2 |
2021-02-01 | The article improves the process of dielectric barrier discharge (DBD) activated anode bonding. The treated surface was characterized by the hydrophilic surface test. The results showed that the hydrophilic angle was significantly reduced under nano-gap conditions and the optimal discharge voltage was 2 kV Then, the anodic bonding and dielectric barrier discharge activated bonding were performed in comparison experiments, and the bonding strength was characterized by tensile failure test. The results showed that the bonding strength was higher under the nano-gap dielectric barrier discharge. This process completed 110 °C ultra-low temperature anodic bonding and the bonding strength reached 2 MPa. Finally, the mechanism of promoting bonding after activation is also discussed. 本文对介质阻挡放电(DBD)活化阳极键合工艺进行了改进. 通过亲水性表面测试来表征处理后的表面, 结果表明纳米间隙条件下亲水角明显降低并得到最优的放电电压为 2 kV. 然后, 进行了阳极键合与介质阻挡放电活化键合的对比试验, 通过拉伸破坏测试来表征键合强度, 结果表明纳米间隙下活化键合强度更高. 完成了 110 °C 低温下的阳极键合,键合强度为 2 MPa. 最后讨论了活化后促进键合的机理. | Ultra-low temperature anodic bonding of silicon and glass based on nano-gap dielectric barrier discharge | 10.1007/s11771-021-4607-z |
2021-02-01 | Waterflooding is the most widely applied improved oil recovery technique. Recently, there has been growing interest in the chemistry and ionic composition of the injected water. Low-salinity waterflooding (LSWF) is a relatively recent enhanced oil recovery technique that has the ability to alter the crude oil/brine/rock interactions and improve oil recovery in both clastics and carbonates. In this paper, the increase in the recovery factor during LSWF was modeled based on the exchange of divalent cations (Ca 2+ and Mg 2+ ) between the aqueous phase and the carbonate rock surface. Numerical simulations were performed using laboratory coreflood data, and oil recovery and pressure drop from experimental works were successfully history matched. The ion exchange equivalent fractions, effluent ions concentrations, changes in mineral moles, and pH have also been examined. Besides, an investigation of multi-component ionic exchange as a mechanism responsible for wettability alteration during LSWF in heterogeneous low-permeability carbonate cores is presented. The results show that wettability alteration is responsible for the increase in oil recovery during LSWF, as reflected by the shift in the crossover points of the relative permeability curves. A sensitivity study done on many key parameters (e.g., timing of LSWF injection, injection rate and temperature) and the mechanistic modeling method revealed that they all have huge effects on the process. | Application of Low-Salinity Waterflooding in Carbonate Cores: A Geochemical Modeling Study | 10.1007/s11053-020-09712-5 |
2021-02-01 | Yttrium silicate is one of the promising environmental barrier coating materials used to protect ceramic matrix composites (CMCs) under specific operating conditions. In this paper, yttrium monosilicate (Y 2 SiO 5 , YMS) nanoparticles were synthesized using a molten salt method with a low synthesis temperature. To find the optimal experimental parameters, YMS nanoparticles were synthesized under different conditions using the molten salt method. The experimental parameters, such as different precursor/salt ratios, precipitants, calcination temperatures, and holding times, were studied. The samples were systematically characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET method. The results showed that all the parameters we mentioned have effects on the synthesis of Y 2 SiO 5 nanoparticles, especially the calcination temperature, the precipitant, and holding time. | Effects of preparing conditions on the synthesis of Y2SiO5 nanoparticles by low-temperature molten salt method | 10.1007/s41779-020-00507-8 |
2021-02-01 | The current study investigates the effect of microwave processing on low-grade banded iron ore using charcoal, coking coal, and non-coking coal. Charcoal showed better microwave heating response at low temperatures, and the coals exhibit better heating response at higher temperatures. Low carbon dosage ~ 12% is sufficient to generate concentrate with 61.8% iron grade and ~6% for 94.8% iron recovery comprising of magnetite phase suitable for iron-making applications. The process separation efficiency of ~ 95% is achieved at 6% carbon dosage and decreases with an increase in carbon due to formation of the fayalite phase. The metallization degree showed a strong dependency on reductant dosage and achieved a maximum value of 22.7% at 18% charcoal. The comparison of ore with pure iron oxide and the synthetic mixture of iron oxide indicated that the underlying bonding due to banded structure enhances the Joule heating during microwave irradiation and thereby aids in attaining higher temperature and better separation. | Microwave Processing of Low-Grade Banded Iron Ore with Different Reductants | 10.1007/s42461-020-00304-8 |
2021-02-01 | We report the cause of degradation of low-temperature amorphous indium-gallium-zinc-oxide (a-IGZO) coplanar thin-film transistors (TFTs). As the deposition temperature of the buffer layer was changed from 400 to 200 °C, the field-effect mobility decreased considerably from 15 to 3 cm 2 V −1 s −1 , the subthreshold swing (SS) increased from ~ 150 to 280 mV dec −1 , the threshold voltage shift (ΔV th ) under negative bias temperature stress (NBTS) increased from − 0.27 to − 0.33 V, and ΔV th under a positive bias temperature stress (PBTS) increased significantly from 0 to 4.9 V. From the results of high-resolution transmission electron microscopy (HR-TEM) and X-ray reflectivity (XRR), the poor roughness created by sputtering damage of the interface between the gate insulator (GI) and the a-IGZO is the cause of degradation. In addition, through an atomic probe tomography (APT) analysis, the reason low-temperature TFTs have poorer PBTS stability than NBTS is carefully to be due to zinc (Zn)-related defects that create ionized oxygen vacancies. Based on these results, we introduce strategies for realizing low-temperature oxide TFTs using vacuum process. Please confirm if the author names are presented accurately and in the correct sequence as given name, middle name/initial, family name. Also, kindly confirm the details in the metadata are correct. We confirmed all author names. Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary. We checked all authors and their affiliations. | Finding the cause of degradation of low-temperature oxide thin-film transistors | 10.1007/s40042-021-00069-3 |
2021-02-01 | Poly( N , N -bis(2-methoxyethyl)acrylamide) (PbMOEAm) featuring two classical chemical motifs from non-ionic water-soluble polymers, namely, the amide and ethyleneglycolether moieties, was synthesized by reversible addition fragmentation transfer (RAFT) polymerization. This tertiary polyacrylamide is thermoresponsive exhibiting a lower critical solution temperature (LCST)–type phase transition. A series of homo- and block copolymers with varying molar masses but low dispersities and different end groups were prepared. Their thermoresponsive behavior in aqueous solution was analyzed via turbidimetry and dynamic light scattering (DLS). The cloud points (CP) increased with increasing molar masses, converging to 46 °C for 1 wt% solutions. This rise is attributed to the polymers’ hydrophobic end groups incorporated via the RAFT agents. When a surfactant-like strongly hydrophobic end group was attached using a functional RAFT agent, CP was lowered to 42 °C, i.e., closer to human body temperature. Also, the effect of added salts, in particular, the role of the Hofmeister series, on the phase transition of PbMOEAm was investigated, exemplified for the kosmotropic fluoride, intermediate chloride, and chaotropic thiocyanate anions. A pronounced shift of the cloud point of about 10 °C to lower or higher temperatures was observed for 0.2 M fluoride and thiocyanate, respectively. When PbMOEAm was attached to a long hydrophilic block of poly( N , N -dimethylacrylamide) (PDMAm), the cloud points of these block copolymers were strongly shifted towards higher temperatures. While no phase transition was observed for PDMAm-b-pbMOEAm with short thermoresponsive blocks, block copolymers with about equally sized PbMOEAm and PDMAm blocks underwent the coil-to-globule transition around 60 °C. | Poly(N,N-bis(2-methoxyethyl)acrylamide), a thermoresponsive non-ionic polymer combining the amide and the ethyleneglycolether motifs | 10.1007/s00396-020-04701-9 |
2021-02-01 | A new method for separating and recovering tin from a low-grade tin middling with high Si content and low Fe content by roasting with anthracite coal was researched by studying the reaction mechanism and performing an industrial test, in which the Sn was sulfurized into SnS(g) and then collected using a dust collector. The Fe-Sn alloy may be formed at roasting temperatures above 950°C, and like the roasting temperature increases, the Sn content and Sn activity in this Fe-Sn alloy decrease. Also, more FeS can be formed at higher temperatures and then the formation of FeO-FeS with a low melting point is promoted, which results in more serious sintering of this low-grade tin middling. And from the thermodynamics and kinetics points of view, the volatilization of the Sn decreases at extremely high roasting temperatures. The results of the industrial test carried out in a coal-fired rotary kiln show that the Sn volatilization rate reaches 89.7% and the Sn is concentrated in the collected dust at a high level, indicating that the Sn can be effectively extracted and recovered from the low-grade tin middling with a high Si content and low Fe content through a reduction—sulfurization roasting process. | Tin recovery from a low-grade tin middling with high Si content and low Fe content by reduction—sulfurization roasting with anthracite coal | 10.1007/s12613-020-2038-8 |
2021-02-01 | The present paper focuses on the production of a below zero emission reducing gas for use in raw iron production. The biomass-based concept of sorption-enhanced reforming combined with oxyfuel combustion constitutes an additional opportunity for selective separation of CO 2 . First experimental results from the test plant at TU Wien (100 kW) have been implemented. Based on these results, it could be demonstrated that the biomass-based product gas fulfills all requirements for the use in direct reduction plants and a concept for the commercial-scale use was developed. Additionally, the profitability of the below zero emission reducing gas concept within a techno-economic assessment is investigated. The results of the techno-economic assessment show that the production of biomass-based reducing gas can compete with the conventional natural gas route, if the required oxygen is delivered by an existing air separation unit and the utilization of the separated CO 2 is possible. The production costs of the biomass-based reducing gas are in the range of natural gas-based reducing gas and twice as high as the production of fossil coke in a coke oven plant. The CO 2 footprint of a direct reduction plant fed with biomass-based reducing gas is more than 80% lower compared with the conventional blast furnace route and could be even more if carbon capture and utilization is applied. Therefore, the biomass-based production of reducing gas could definitely make a reasonable contribution to a reduction of fossil CO 2 emissions within the iron and steel sector in Austria. | Evaluation of biomass-based production of below zero emission reducing gas for the iron and steel industry | 10.1007/s13399-020-00939-z |
2021-02-01 | To quantitatively assess the risks associated with Carbon Capture and Storage (CCS) technology, a better understanding of the dispersion characteristics of CO 2 released from a high-pressure pipeline is necessary. The dispersion process is complicated as CO 2 is denser than air, and the Joule-Thomson effect causes sharp drop of the temperature. In this study, computational fluid dynamics (CFD) technique was used to investigate the CO 2 dispersion. The CFD model is validated by simulating a full-size blasting test. The influence of topography and low temperature at the release source on the dispersion of CO 2 released from buried CO 2 pipelines over complex terrain types was studied. This study provides a viable method for the assessment of the risks associated with CCS. | Dispersion of carbon dioxide released from buried high-pressure pipeline over complex terrain | 10.1007/s11356-020-11012-7 |
2021-02-01 | MicroRNAs (miRNAs) play important roles in post-transcriptional regulation as well as in various biological and metabolic processes. Lilium pumilum originated from northern China with a high ornamental value, and is important for Lilium resistance breeding. The dormancy of the bulbs has a serious effect on flowering quality. In this study, the miRNAs from samples at 0 days ( S 1 stage), 30 days ( S 2 stage), 60 days ( S 3 stage) and 90 days ( S 4 stage) of cold storage were sequenced to reveal the dormancy mechanism of Lilium pumilum . Through ultrastructural observation and physiological index measurement, we found that Lilium pumilum bulbs were released from dormancy during low-temperature storage. We further conducted miRNAs sequencing; a total of 17 conserved miRNAs were identified from 12 families, two nonconserved miRNAs were found that belonged to two families, and 38 novel miRNAs were predicted. MiRNA-target pairs analysis showed that some biological processes, including antioxidant reactions, epigenetic modification and abiotic stress, were induced in response to low-temperature conditions. Some transcription factors, plant hormone signalling pathways, and enzymes involved in plant growth and development were also activated to break the bulb dormancy. The study initially revealed the complex regulatory mechanisms of miRNAs for dormancy release during low-temperature storage. Comprehensive sequence information and target gene data were obtained by miRNAs sequencing, which determined that miRNAs regulation of bulb dormancy release in low temperature. | Identification and Expression Analysis of microRNAs in Response to Dormancy Release During Cold Storage of Lilium pumilum Bulbs | 10.1007/s00344-020-10108-1 |
2021-02-01 | In this paper, a wearable medical sensor system is designed for long-term healthcare applications. This system is used for monitoring temperature, heartbeat, blood oxygen saturation (SpO 2 ), and the acceleration of a human body in real-time. This system consists of a temperature sensor, a pulse oximeter sensor, an accelerometer sensor, a microcontroller unit, and a Bluetooth low energy module. Batteries are needed for supplying energy to this sensor system, but batteries have a limited lifetime. Therefore, a photovoltaic–thermoelectric hybrid energy harvester is developed to power a wearable medical sensor system. This harvester provides sufficient energy and increases the lifetime of the sensor system. The proposed hybrid energy harvester is composed of a flexible photovoltaic panel, a thermoelectric generator module, a DC–DC boost converter, and two super-capacitors. Experimentally, in active-sleep mode, the sensor system consumes an average power of 2.13 mW over 1 h and works without the energy harvester for 46 h. Finally, the experimental results illustrate the sustainable and long-term monitoring operation for the medical sensor system. | A Self-powered Wearable Wireless Sensor System Powered by a Hybrid Energy Harvester for Healthcare Applications | 10.1007/s11277-020-07840-y |
2021-02-01 | Phascolosoma esculenta is an intertidal organism that has recently attracted attention because of its ability to survive at relatively low temperatures. However, the gene regulation in P. esculenta in relation to its response to low temperatures is unclear. To explore the low temperature adaptability of P. esculenta , this study analyzed the changes in the morphology and hsp70 and hsp90 gene expression of P. esculenta exposed to a low temperature gradient. At 5°C, P. esculenta stretched and softened, and some individuals moved apart from the group. Histological analysis revealed cuticle breaches, myofiber scattering, disruption of the body wall, and epithelial layer dispersion and muscle fiber rupturing in the nephridium. Furthermore, the mRNA expression levels of hsp70 and hsp90 increased under acute low temperature stress, suggesting that these genes function in low temperature tolerance. Overall, low temperature stress causes morphological changes and histological damage in P. esculenta , and hsp70 and hsp90 potentially function in the low temperature adaptability of P. esculenta. Our results provide new insights into the adaptive strategies of P. esculenta under low temperature environments. | Effects of Low Temperature Stress on the Morphology and hsp70 and hsp90 Gene Expression of Phascolosoma esculenta | 10.1007/s11802-021-4475-z |
2021-02-01 | Freezing stress is a serious environmental factor that obstructs plant development. The root endophytic fungus Piriformospora indica has proved to be effective to confer abiotic stress tolerance to host plants. To investigate how P. indica improves freezing tolerance, we compared the expression profiles of P. indica -colonized and uncolonized Arabidopsis seedlings either exposed to freezing stress or not. Nearly 24 million (93.5%) reads were aligned on the Arabidopsis genome. 634 genes were differentially expressed between colonized and uncolonized Arabidopsis exposed to freezing stress. Interestingly, 193 Arabidopsis genes did not respond to freezing stress but were up-regulated by P. indica under freezing stress. Freezing stress-responsive genes encoded various members of the WRKY, ERF, bHLH, HSF, MYB and NAC transcription factor families. The qRT-PCR analyses confirmed the high-throughput sequencing results for 28 genes. Functional enrichment analysis indicated that the fungus mainly controls genes for freezing-stress related proteins involved in lipid and ion transport, metabolism pathways and phytohormone signaling. Our findings identified novel target genes of P. indica in freezing-stress exposed plants and highlight the benefits of the endophyte for plants exposed to a less investigated environmental threat. | Transcriptome analysis of Arabidopsis reveals freezing-tolerance related genes induced by root endophytic fungus Piriformospora indica | 10.1007/s12298-020-00922-y |
2021-02-01 | Manganese was leached from a low-grade manganese ore (LGMO) using banana peel as the reductant in a dilute sulfuric acid medium. The effects of banana peel amount, H 2 SO 4 concentration, reaction temperature, and time on Mn leaching from the complex LGMO were studied. A leaching efficiency of ∼98% was achieved at a leaching time of 2 h, banana peel amount of 4 g, leaching temperature of 120°C, manganese ore amount of 5 g, and sulfuric acid concentration of 15vol%. The phase, microstructural, and chemical analyses of LGMO samples before and after the leaching process confirmed the successful leaching of manganese. Furthermore, the leaching process followed the shrinking core model and the leaching rate was controlled by a surface chemical reaction (1 − (1 − x ) 1/3 = kt ) mechanism with an apparent activation energy of 40.19 kJ·mol −1 . | Hydrometallurgical leaching and kinetic modeling of low-grade manganese ore with banana peel in sulfuric acid | 10.1007/s12613-020-2069-1 |
2021-02-01 | A series of novel N-doped carbon-coated Li 3 V 2 (PO 4 ) 3 (LVPC/N) composites were synthesized by rheological phase method with melamine as nitrogen source. The results showed that N-doping did not affect the main structure of Li 3 V 2 (PO 4 ) 3 /C (LVPC) but only changed the structure and properties of the coating layer, which effectively improved the structural stability and electrochemical performance of LVPC. When the ratio of citric acid to melamine was 5:3, the properties of LVPCN composite were the best. The initial discharge specific capacity was 195 mAh g −1 at 30 mA g −1 in the voltage range of 3.0–4.8 V. After 100 cycles of charge and discharge, the discharge capacity was still 165 mAh g −1 , and the capacity retention rate was increased to 85%. Owing to the low cost, high initial discharge capacity, and long lifespan, we believe that the LVPC/N composite is significantly competitive to other cathode materials for application in lithium-ion batteries. | Nitrogen-doped carbon-coated Li3V2(PO4)3 as cathode materials for high-performance lithium storage | 10.1007/s11581-020-03878-x |
2021-02-01 | IoT devices become more and more popular which implies a growing interest in easily maintainable and battery-independent power sources, as wires and batteries are unpractical in application scenarios where billions of devices get deployed. To keep the costs low and to achieve the smallest possible form factor, SoC implementations with integrated energy harvesting and power management units are a welcome innovation. On-chip energy harvesting solutions are typically only capable of supplying power in the order of microwatts. A significant design challenge exists for the functional blocks of the IoT-SoC as well as for the power management unit itself as the harvested voltage has to be converted to a higher and more usable voltage. Simultaneously, the power management blocks have to be as efficient as possible with the lowest possible quiescent currents. In this paper, we provide a look at on-chip microwatt power management. Starting with the energy-harvesting from RF power or light, we then show state-of-the-art implementations of ultra-low power voltage references and ultra-low power low-dropout regulator (LDO) designs. IoT-Geräte werden immer verbreiterter. Wachsendes Interesse gibt es dabei an einfach wartbaren und Batterie-unabhängigen Energiequellen, da Kabel und Batterien in Applikationen, wo Milliarden von Geräten in Einsatz sind, unpraktisch sind. Um die Kosten niedrig zu halten und den kleinstmöglichen Form-Faktor zu erreichen, sind SoC-Implementierungen mit integriertem Energy Harvesting und Power-Management-Blöcken eine willkommene Innovation. On-Chip Energy Harvesting-Lösungen können typischerweise Energie nur in der Größenordnung von Microwatt liefern. Es existiert dadurch nicht nur eine große Design-Herausforderung für die funktionalen Blöcke des IoT-SoC, sondern auch für die Power-Management-Einheiten, da die gewonnene Energie oft in eine höhere und besser nutzbare Spannung konvertiert werden muss. Gleichzeitig müssen die Power-Management-Blöcke so effizient wie möglich sein und niedrigste Ruheströme vorweisen. In dieser Arbeit geben wir einen Einblick in vollintegriertes (On-Chip) Microwatt Power Management. Beginnend bei Energy Harvesting von RF-Energie oder Licht, zeigen wir weiters aktuelle Implementierungen von Ultra-Low-Power-Spannungsreferenzen und Ultra-Low-Power-Low-Dropout-Spannungsreglern (LDO)s. | Microwatt power management: challenges of on-chip energy harvesting | 10.1007/s00502-020-00859-w |
2021-02-01 | The propellant supply system of a liquid rocket engine using an electric pump has high reliability because of the relatively small number of components. The system also has the merit of a quick response and ease of control owing to its simple configuration. Recently, the rocket lab developed the Rutherford engine, which has an electric pump cycle, because of the improved technology in the electric motor and battery. This paper examined the development of the electric-pump cycle and compared the performance with other cycles for a small-sized low-thrust rocket engine. Performance analysis and mass estimation were conducted using the developed analysis program, in which reliability in mass estimation was improved based on the designed configuration or real performance data from commercial products. In addition, the modeling method and analysis procedure were described in detail. The results showed that it is possible to develop a small-sized engine with an electric-pump cycle when the present technologies are applied. The electric-pump cycle had a smaller dry mass than the gas-generator cycle, even at a low thrust level of 500 N, and showed higher performance in specific impulse and speed increments. | Performance Analysis and Mass Estimation of a Small-Sized Liquid Rocket Engine with Electric-Pump Cycle | 10.1007/s42405-020-00325-z |
2021-02-01 | Many oak stands ( Quercus spp.) have been managed as coppices for firewood production for centuries in the Mediterranean area. After the abandonment of firewood production during the 1980s, current management practices attempt to convert coppices into coppices-with-standards through thinning and promoting forest regeneration via sexual reproduction. In this work, we used long-term data from repeated forest inventories and dendrometers in a thinning trial to assess the effects of thinning and climate on the intra- and inter-annual growth dynamics of Quercus pyrenaica Willd. coppices. Our results revealed that thinning favored the growth of Q. pyrenaica trees, especially when the stand density reduction was high (ca. 50% of the basal area extracted). Unthinned plots displayed more natural mortality i.e., self-thinning. Growth was enhanced with low vapor pressure deficit. Intense thinning treatments displayed higher intra-annual growth rates and interacted positively with rainfall to induce higher growth. We conclude that thinning, especially intensive thinning, may alleviate the negative effects of dry years and thus could provide a potential measure to adapt these stands to the different climatic scenarios with higher temperatures and less precipitation within the framework of sustainable forest management. | Influence of climate and thinning on Quercus pyrenaica Willd. coppices growth dynamics | 10.1007/s10342-020-01322-3 |
2021-02-01 | It is unclear whether the frequently observed increase in non-structural carbohydrates (NSC) in plants exposed to low temperatures or drought reflects a higher sensitivity of growth than photosynthesis in such conditions (i.e. sink limitation), or a prioritization of carbon (C) allocation to storage. Alpine areas in Mediterranean-type climate regions are characterized by precipitation increases and temperature decreases with elevation. Thus, alpine plants with wide elevational ranges in Mediterranean regions may be good models to examine these alternative hypotheses. We evaluated storage and growth during experimental darkness and re-illumination in individuals of the alpine plant Phacelia secunda from three elevations in the Andes of central Chile. We hypothesized that storage is prioritized regarding growth in plants of both low- and high elevations where drought and cold stress are greatest, respectively. We expected that decreases in NSC concentrations during darkness should be minimal and, more importantly, increases in NSC after re-illumination should be higher than increases in biomass. We found that darkness caused a significant decrease in NSC concentrations of both low- and high-elevation plants, but the magnitude of the decrease was lower in the latter. Re-illumination caused higher increase in NSC concentration than in biomass in both low- and high-elevation plants (1.5- and 1.9-fold, respectively). Our study shows that C allocation in Phacelia secunda reflects ecotypic differences among elevation provenances and suggests that low temperature, but not drought, favours C allocation to storage over growth after severe C limitation. | Carbon allocation to growth and storage depends on elevation provenance in an herbaceous alpine plant of Mediterranean climate | 10.1007/s00442-020-04839-x |
2021-02-01 | Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas reservoirs. However, it is associated with low-pressure resistance and poor sealing performance. To enhance the performance of nylon cord rubber, a three-dimensional numerical model of the nylon cord rubber was established and its accuracy experimentally determined. The Plackett–Burman test, the Steepest climbing test and the Response surface method were used to acquire the polynomial response surface model connecting structural parameters with bearing and sealing pressure. Using genetic algorithms, optimal structural parameters of nylon cord rubber were determined depending on field operation. The reliability of the optimized results was verified by laboratory tests. It was shown that after optimization, the bearing capacity of the expandable packer increased by 25% while the sealing performance increased by 66%. In addition, the bearing pressure was 70 MPa while the sealing pressure was 50 MPa. These measurements effectively met the on-site requirements of high-pressure and fine fracturing in low-permeability oil and gas reservoirs. | Multi-objective optimization and experiment of nylon cord rubber in expandable packer | 10.1007/s12182-020-00539-6 |
2021-02-01 | A novel hybrid silicon Single Electron Transistor Metal Oxide Semiconductor (SETMOS) logic is evaluated for its functionality and usability. Emphasis is given on obtaining functionality at ambient temperature with low power consumption and significant drive. Performance is evaluated with respect to 22 nm Complementary Metal Oxide Semiconductor (CMOS) technology and other popular hybrid SETMOS topologies. The results produced here not only comprehend performance of various SET-CMOS based logic architectures, but they are also closer to real values as they consider effect of parasitic in respective topologies. Proposed work is power efficient, scalable, accurate and process compatible logic design, which uses less hardware and operates at room temperature. It relies on CMOS compatible fabrication of Silicon SET and P-Type Metal Oxide Semiconductor (PMOS) on same chip footprint. When compared with contemporary SETMOS hybrid circuits, it offers 90.29 % power improvement at the cost of 16.53 % reduction in speed. | Novel Hybrid Silicon SETMOS Design for Power Efficient Room Temperature Operation | 10.1007/s12633-020-00461-x |
2021-02-01 | The cation-independent bioflocculant (59LF) extracted from Klebsiella sp. 59L was characterized. 59LF consisted of protein (4.8%) and total sugar (85.2%) with high molecular weight (93.82% of 2120 kDa), and total sugar was composed of 76.45% of neutral sugar, 3.65% of uronic acid, and 1.43% of amino sugar. Results indicated that 59LF was pH tolerant and thermally stable, and the maximum yield of 59LF was 4.078 g/L after 48 h culture. The optimal flocculating activity for Kaolin particles was obtained when the dosage of 59LF was 7.0 mg/L without additional metal ions as coagulant aids. Furthermore, the surface properties of 59LF were observed using a Fourier-transform infrared spectrophotometer and X-ray photoelectron spectroscopy, whereas a porous structure was detected by a scanning electron microscope. Thus, a primary flocculation mechanism of 59LF was proposed. This study provided a potential cation-independent bioflocculant with high productivity and low dosage in future application. | Optimized production and characterization of cation-independent bioflocculant produced by Klebsiella sp. 59L | 10.1007/s11356-020-11162-8 |
2021-02-01 | Abstract Chloroaluminate ionic liquids are the most promising electrolytes for the low-temperature electrolysis of aluminum and in aluminum-ion batteries. An important problem in this area is the determination of the ionic composition and the ion concentrations in an ionic liquid. The low-temperature AlCl 3 –1-butyl-3-methylimidazolium chloride melt is studied in the acidic range of aluminum chloride concentrations (at the molar fractions of aluminum chloride from 0.5 to 0.67). The cycle of measurements of the ionic liquid density is carried out by a dilatometric method in a wide temperature range (from 0 to 100°C) in order to calculate the molar concentrations of ions in the electrolyte under study. The molar volumes of the ionic liquid are calculated from the experimental values of density. The isotherms and polytherms of the density and molar volume of the ionic liquid are linear. The ionic liquid density decreases and the molar volume increases with increasing temperature. The density increases and the molar volume of the ionic liquid decreases with increasing molar fraction of aluminum chloride in the melt due to an increase in the concentration of the heavier anion ( $${\text{A}}{{{\text{l}}}_{{\text{2}}}}{\text{Cl}}_{{\text{7}}}^{-}$$ ) compared to that of the $${\text{AlCl}}_{{\text{4}}}^{-}$$ anion. The ionic liquid under study is presented as a mixture of two salts: 1-butyl-3-methylimidazolium– $${\text{AlCl}}_{{\text{4}}}^{-}$$ (ionic liquid at an aluminum chloride molar fraction of 0.5) and 1-butyl-3-methylimidazolium– $${\text{A}}{{{\text{l}}}_{{\text{2}}}}{\text{Cl}}_{{\text{7}}}^{-}$$ (ionic liquid at an aluminum chloride molar fraction of 0.67). The rule of additive addition of densities and molar volumes is proved for mixtures of these salts. The molar concentrations of ions present in the mixture are calculated. The dependences of the concentration of each ion on the temperature and the molar fraction of aluminum chloride can be described by linear functions. The molar concentrations of each type of ions decrease with increasing temperature due to an increase in the molar volume. | Calculation of the Molar Concentrations of Ions in the Molten System AlCl3–1-Butyl-3-Methylimidazolium Chloride | 10.1134/S0036029521020063 |
2021-02-01 | The feasibility of converting full nitritation to partial nitritation/anammox (PN/A) at ambient temperature (20 °C) was investigated in a continuous granular reactor. The process was conducted without anammox bacteria inoculation for the treatment of 70 mg L −1 of low-strength ammonium nitrogen wastewater. Following the stepwise increase of the nitrogen loading rate from 0.84 to 1.30 kg N m −3 d −1 in 320 days of operation, the removal efficiency of total inorganic nitrogen (TIN) exceeded 80% under oxygen-limiting conditions. The mature PN/A granules, which had a compact structure and abundant biomass, exhibited a specific TIN removal rate of 0.11 g N g −1 VSS d −1 and a settling velocity of 70.2 m h −1 . This was comparable with that obtained at above 30 °C in previous reports. High-throughput pyrosequencing results revealed that the co-enrichment of aerobic and anaerobic ammonium-oxidizing bacteria identified as genera Nitrosomonas and Candidatus Kuenenia, which prompted a hybrid competition for oxygen and nitrite with nitrite-oxidizing bacteria (NOB). However, the overgrowth of novel NOB Candidatus Nitrotoga adapted to low temperatures and low nitrite concentration could potentially deteriorate the one-stage PN/A process by exhausting residual bulk ammonium under long-term excessive aeration. | Conversion of full nitritation to partial nitritation/anammox in a continuous granular reactor for low-strength ammonium wastewater treatment at 20 °C | 10.1007/s10532-020-09923-w |
2021-02-01 | Electrochemical machining (ECM) is becoming increasingly important for the efficient machining of parts with a large machining area. This is an addition challenge for ECM because of the very high machining current. To overcome this difficulty, a direct and effective strategy is to adopt the machining mode that uses a low-concentration electrolyte with a low current density. The purpose of this study is to reveal the electrochemical behaviour and surface morphology in low-concentration electrolyte. The polarization behavior of Ti-48Al-2Cr-2Nb is measured by linear sweep voltammetry and cyclic voltammetry curves. The ηω-j curves demonstrate the special dissolution behaviour of Ti-48Al-2Cr-2Nb at low current densities. The surface morphology, surface quality, and dissolution mechanism are analysed in three low-concentration electrolytes at different current densities after the ECM dissolution experiments. The results demonstrate that Ti-48Al-2Cr-2Nb exhibits three unique dissolution morphologies in the three solutions, and we found that the γ-TiAl phase dissolves faster than the α 2 -Ti 3 Al phase. These results also show that 1% NaCl solution is more suitable for Ti-48Al-2Cr-2Nb in ECM compared with the other two solutions, considering its good surface quality, low breakdown potential, and high material removal rate. Later, the dissolution process of the sample in 1% NaCl solution at different corrosion times is revealed. Moreover, a dissolution model is proposed for the electrochemical dissolution behaviour of Ti-48Al-2Cr-2Nb in 1% NaCl solution. | Surface morphology and electrochemical behaviour of Ti-48Al-2Cr-2Nb alloy in low-concentration salt solution | 10.1007/s11431-019-1558-8 |
2021-02-01 | Injection of low-salinity water into carbonate reservoirs has gained attention as a viable and efficient enhanced oil recovery approach through wettability alteration as prevailing mechanism. However, modeling and implementation of wettability alteration during simulation of low-salinity water injection are challenging because of the complex ion interactions and chemical reactions in the brine and oil mixture as well as on the rock surface. It is noteworthy that wettability alteration is usually considered instantaneous in black oil simulation. The main purpose of this work was to put this assumption into perspective; thus, it aims at discerning under what circumstances the instantaneous wettability alteration approach is plausible during simulation of low-salinity water flooding. To answer this question, an approach was proposed to consider gradual wettability alteration during simulation of low-salinity water flooding and the results were compared with instantaneous wettability alteration method. The results show that the impacts of simultaneous increase in $${\text{SO}}_{4}^{2 - } ,{\text{Ca}}^{2 + }$$ SO 4 2 - , Ca 2 + concentrations and temperature cause the difference between gradual and instantaneous wettability alteration to be more noticeable at the early times of injection. Therefore, the results highlight that the impact of gradual consideration would be important at the early time of low-salinity water flooding process. | Gradual or Instantaneous Wettability Alteration During Simulation of Low-Salinity Water Flooding in Carbonate Reservoirs | 10.1007/s11053-020-09726-z |
2021-02-01 | We investigated the effect of nanosized NbC precipitates on hydrogen-induced cracking (HIC) of high-strength low-alloy steel by conducting slow-strain-rate tensile tests (SSRT) and performing continuous hydrogen charging and fracture analysis. The results reveal that the HIC resistance of Nb-bearing steel is obviously superior to that of Nb-free steel, with the fractured Nb-bearing steel in the SSRT exhibiting a smaller ratio of elongation reduction ( I δ ). However, as the hydrogen traps induced by NbC precipitates approach hydrogen saturation, the effect of the precipitates on the HIC resistance attenuate. We speculate that the highly dispersed nanosized NbC precipitates act as irreversible hydrogen traps that hinder the accumulation of hydrogen at potential crack nucleation sites. In addition, much like Nb-free steel, the Nb-bearing steel exhibits both H-solution strengthening and the resistance to HIC. | Effect of nanosized NbC precipitates on hydrogen-induced cracking of high-strength low-alloy steel | 10.1007/s12613-020-2167-0 |
2021-02-01 | Because of the toxicity of Gd(III) complexes and the poor T 1 magnetic resonance imaging (MRI) contrast of superparamagnetic iron oxide, the development of new stable, non-toxic, and efficient contrast agents is desirable. Herein, tannic acid (TA), a large natural polyphenol, and bovine serum albumin (BSA) were used to construct non-toxic Fe(III) complexes with increased relaxivity based on a strategy slowing the molecular spin. Compared with the commercial T 1 contrast agent Magnevist, TA-Fe@BSA not only exhibits comparable T 1 MRI contrast enhancement under 0.5, 1 and 7 T magnetic fields both in vitro and in vivo , but also has better stability and biocompatibility. Moreover, TA-Fe@BSA with near-infrared (NIR) absorption demonstrates efficient tumor ablation via photothermal effects. These results demonstrate their strong potential as an alternative T 1 MRI contrast agent and tumor theranostics agent in clinical settings. Gd(III)配合物和超顺磁性氧化铁(SPION)是目前常见的 T 1 MRI造影剂, 然而由于Gd(III)的毒性和SPION较差的对比度, 需要开发出新的稳定、 无毒的高效造影剂. 本论文基于减慢分子自旋的策略, 利用生物安全的天然多酚单宁酸和牛血清白蛋白来构建无毒的Fe(III)复合物TA-Fe@BSA. 该复合物具有良好的增强弛豫性能, 在溶液和体内测试中, 在0.5, 1和7 T磁场下均具有与商用 T 1 造影剂Magnevist®相当的 T 1 MRI增强造影效果, 而且具有良好的稳定性和生物相容性. 此外, 具有近红外吸收的TA-Fe@BSA基于其光热效应, 也表现出了有效的肿瘤消融作用. 这些结果证明了TA-Fe@BSA作为替代性 T 1 MRI造影剂和肿瘤治疗药物的潜力. | Ultrasensitive iron-based magnetic resonance contrast agent constructed with natural polyphenol tannic acid for tumor theranostics | 10.1007/s40843-020-1434-1 |
2021-02-01 | A technique to detect the bolt looseness in steel frame using the transfer impedance technique, which is a dual piezoelectric material technique, for bolted joint structural health monitoring is experimentally studied. An expensive impedance analyzer should be used to employ the single piezoelectric material technique (SPMT) while a general function generator and a digital multimeter can be used to employ the transfer impedance technique. Therefore, the low-cost fault detection could be carried out. A steel frame consisting of high tensile bolted connections with the splice angles was made, and the preload forces of the bolts were gradually reduced and the damage tests were carried out. The damage indexes were obtained using the transfer impedance technique and it was found that the fault existence of the bolted joint could be reasonably detected and the variations of the damage indexes tend to be increased as the degree of bolt looseness increases. The estimation results were similar to the results of the SPMT using the impedance analyzer. These results support that it is possible to estimate the bolt looseness of the bolted joint based on the impedance technique at low-cost, excluding an expensive impedance analyzer. It could be used effectively for bolted joint structural health monitoring if the study on identification of fault location and severity using the transfer impedance technique is supplemented in the future. | An Experimental Study on Bolt Looseness Monitoring Using Low-Cost Transfer Impedance Technique | 10.1007/s13296-020-00442-1 |
2021-02-01 | The concentration of different maceral groups and minerals in coal influence the quality as each of them behaves differently during heat treatment. The purpose of this study is to know how these are behaving at different temperature conditions. Therefore, various macerals and minerals were concentrated by using heavy liquids of different specific gravities (1.3, 1.7 and 1.9). The generated density fractions were treated with heat at 400, 600, 800 and 1000 °C. All the density fractions at various temperature conditions along with feed sample were investigated by optical microscopy, X-ray diffractometry, electron-probe microanalysis and Fourier transform infrared spectroscopy analysis. The results suggest that fusinite and sclerotinite are the most stable macerals, whereas quartz is the most stable mineral. Telocollinite is found to be oxidized very prominently at 400 °C. Siderite and pyrite alter to form hematite above 400 °C and 800 °C, respectively. Kaolinite converts to metakaolin followed by mullite with increasing temperature. | Effect of Heat on Organic and Inorganic Components in Some Non-coking Lower Gondwana Coals | 10.1007/s12666-020-02168-4 |
2021-02-01 | The Wuchuan–Sihui–Shaoguan (WSS) exhalative sedimentary pyrite belt in the southwestern part of the Qinzhou–Hangzhou (Qin–Hang) belt is the most important sulfur industry base in China. However, a wide range of metallogenetic ages spanning from Ediacaran to Devonian has been reported in the literature. This age range does not support the idea that the typical character of “coeval mineralization” in an exhalative sedimentary mineralization belt in China and worldwide. Therefore, the precise determination of mineralization ages of representative deposits is necessary to provide guides for exploration and metallogenetic models. The Dajiangping pyrite deposit is a typical example of this kind of deposits and is also the largest deposit with a proven reserve of 210 Mt. This deposit was thought to have formed in Ediacaran or Devonian. In this study, 2–3 layers of 10–25 cm thick 2M 1 -type microcrystalline muscovite slate abruptly embedded in the No. IV massive orebody of the deposit has been identified to be low-grade metamorphic K-bentonite. A Concordia zircon LA–ICP–MS U–Pb age of 432.5 ± 1.3 Ma (mean standard weighted deviation of concordance and equivalence = 1.2; N = 11) has been yielded for the low-grade metamorphic K-bentonite. This age is distinctly different from the Rb–Sr isochron age of 630.1 ± 7.3 Ma for siliceous rock at the top of the No. III banded orebody and the Re–Os isochron age of 389 ± 62 Ma for pyrites from a laminated orebody. Instead, it is close to the intercept age (429 Ma) of the youngest detrital zircons from sandstone interlayers of the No. III banded orebody. The Concordia age is also coincident with those of the Late Caledonian (400–460 Ma) magmatism-metamorphism events which are widely distributed in Cathaysia Block. Particularly, it agrees well with that of the Early Silurian extensional volcanism (434–444 Ma) which have been revealed in the Dabaoshan, Siqian–Hekou, and Nanjing volcanic basins in northern Guangdong Province and southern Jiangxi Province. Hence, the dating result in this study confirms that the sedimentary time of the ore-host Daganshan Formation is Early Silurian, and implies that the mineralization age of the Dajiangping pyrite deposit should also be Early Silurian. In combination with the Early Silurian age of Shezui pyrite deposit and the Dabaoshan volcanic basin along the WSS pyrite belt, it could be inferred that the WSS pyrite belt provides a record of the northern expanding of Qinzhou–Fangcheng trough in Early Silurian and that the exhalative pyrite mineralization was triggered by the post-collisional extension of the margin of Cathaysia Block after the intracontinental collision between Cathaysia Block and Yangtze Block during Late Caledonian stage. | Early Silurian Wuchuan–Sihui–Shaoguan exhalative sedimentary pyrite belt, South China: constraints from zircon dating for K-bentonite of the giant Dajiangping deposit | 10.1007/s11631-020-00439-x |
2021-02-01 | The temporal and spatial relationships between polyphase folding and faulting, regional metamorphism, and granitoids intrusions are discussed for the low-grade basement rocks of the El Jagüelito Formation from the eastern North Patagonian Massif, Argentina, at the inferred western Gondwana margin. As a result of the tectonometamorphic and magmatic events, a late Cambrian-early Ordovician orogenic belt is revealed in northern Patagonia and shall be named the Transpatagonian orogen. It is an NW–SE-trending belt traced from the extra-Andean North Patagonian Cordillera region via the eastern North Patagonian Massif up to the Atlantic coast in the east. The early Paleozoic Transpatagonian orogen is the result of compressional tectonics, also showing a significant dextral shearing, and regional metamorphism leading to the development of a fold-and-thrust belt with an anticlockwise P–T–D-time path. The double-sided orogen is divided into three tectonometamorphic zones bounded by NW–SE trending major faults. Regional comparisons of our results in the present contribution together with available geological data, allow characterizing the orogen as part of a paired metamorphic belt system, with an outboard low-P/high-T belt (northern Patagonia terrane) and a parallel, inboard medium-P/T belt of Barrowian type (Famatinian Orogen on Gondwana margin), respectively. They are juxtaposed tectonically along with the contact of the suture Huincul Fault Zone. The Transpatagonian orogen was implanted along the southernmost Gondwana margin during the final stages of the supercontinent assembly in the early Paleozoic. The tectonism of the Permian Gondwanide orogeny reworked the Transpatagonian orogen. | Early Paleozoic structural and metamorphic evolution of the Transpatagonian Orogen related to Gondwana assembly | 10.1007/s00531-020-01939-0 |
2021-02-01 | This study aimed to compare the growth performance, food consumption, and acoustic feeding behavior of two size classes of Litopenaeus vannamei fed on extruded and pelleted diets. Two similar diets (35% crude protein) prepared by extrusion or pelletizing methods were offered to two shrimp size classes: small (3.83 ± 0.16 g) and large (10.28 ± 0.37 g). Shrimp were reared in 100-L aquaria (salinity 6 ppt, temperature 28 °C); growth performance and survival were analyzed at the end of 4 and 8 weeks for small and large size classes, respectively. Hydrophones recorded the sounds of shrimp feeding activity for 30-min intervals, after food remains were collected to evaluate consumption. Physical (pellet durability index, hardness, water absorption, density, sinking velocity, dry matter retention) and chemical (aromatic amino acids (AAA) leaching) characteristics of the diets were evaluated before and after soaking. Extruded diet presented higher durability and hardness before soaking, but its higher water absorption resulted in markedly texture softened and higher AAA leaching. Both shrimp size classes presented no significant differences in final mean weight, biomass, weight gain, survival, food conversion, and food consumption between pelleted or extruded diets. The mean acoustic energy did not differ between diets, but larger shrimp produced higher energy during feeding activity. The energy showed a significant progressive decrease along time intervals (10, 20, and 30 min) for both size classes and diets. Despite the different characteristics between pelleted and extruded diets, both resulted in similar shrimp performance and acoustic feeding profile activity under laboratory conditions. | Growth performance and acoustic feeding behavior of two size classes of Litopenaeus vannamei fed pelleted and extruded diets | 10.1007/s10499-020-00636-8 |
2021-02-01 | Combustion of coal create many harmful gases which effect on human health as well as on environment. The sulfur in coal limits its own use, and bio-desulfurization (BDS) shows enormous development potential and the prospects for the application of coal desulfurization. Present study highlights the bioprocess strategies for reduction of sulfur content from coal before combustion. The bioprocess involved the use of Airlift Bioreactor along with Rhodococcus sp . ATCC55309 as biocatalyst. Different nutritional and operational parameters involved to promote sulfur reduction at maximum level. The parameters were investigated are different carbon source, temperature, pH, Agitation speed, and pulp density. The impact of these parameters shows that sulfur removal can be enhanced though optimized conditions. The amount of total sulfur and organic sulfur present in coal were reduced by 33 ± 1.7% and 71 ± 1.5%, respectively, compared to untreated coal at controlled condition of various parameters are 20% (w/v) pulp density, 30 °C, 170 rpm, glucose as carbon source and pH 7. Whereas organic sulfur degrades from coal using Rhodococcus sp . ATCC55309 about 0.36 mM DBT (Di-benzothiophene) within 8 days via 4S-pathway. The maximum conversion of DBT compound into 2-HBP(2-hydroxybiphenyl) by utilizing 30 °C, 170 rpm, 20 pulp density and glucose as carbon source. | Biological assisted organic sulfur removal from low rank indigenous coal using airlift bioreactor | 10.1007/s00449-020-02453-y |
2021-02-01 | Different oil displacement experiments conducted on sandstone and carbonate samples show that low salinity water (LSW) injection can reduce the residual oil saturation (ROS). Recently, surfactant flooding (SF) in combination with low salinity water (known as low salinity surfactant (LSS) flooding) is proposed as a potentially promising hybrid enhanced oil recovery (EOR) process. A lower ROS is reported for a LSS process compared to that seen in SF or with LSW at the same capillary number. The capillary desaturation curve (CDC) is a well-known tool to study the effect of viscous and capillary forces on ROS for different EOR techniques. In this study, ROS data of various LSW, SF, and LSS flooding experiments at different capillary numbers are collected to develop a CDC to analyze the performance of the hybrid LSS method. This can help to analyze the effect of the hybrid method on an extra improvement in sweep efficiency and reduction in residual oil. A lower ROS is observed for LSS compared to LSW and SF in the same capillary number range. Our study shows different behaviors of the hybrid method at different ranges of capillary numbers. Three regions are identified based on the capillary number values. The difference in ROS is not significant in the first region (capillary number in the range of 10 −7 –10 −5 ), which is not applicable in the presence of surfactant due to the low interfacial tension value. A significant reduction in ROS is observed in the second region (capillary number in the range of 10 −5 –10 −2 ) for LSS compared to SF. This region is the most practical range for SF and LSS flooding. Hence, the application of LSS provides a noticeable benefit compared to normal EOR techniques. In the third region (capillary numbers greater than 10 −2 ), where the surfactant flooding is a better performer, the difference in ROS is negligible. | Capillary desaturation curve: does low salinity surfactant flooding significantly reduce the residual oil saturation? | 10.1007/s13202-020-01074-1 |
2021-02-01 | Polyploid breeding is widely used in various marine species. Low salinity treatment is an effective method of inducing triploid of bivalve mollusks. In this study, RNA-seq was performed to determine genes and pathways involved in hyposaline adaption and cell division of Pacific oyster ( Crassostrea gigas ) zygotes, trying to better understand the possible molecular mechanism of hypo-osmotic induction. A total of 26965 unigenes were generated in the de novo assembly of clean Illumina reads with an average length of 934 bp and N50 of 1721 bp. Of 3024 differentially expressed genes (DEGs), 2501 were up-regulated and 523 were down-regulated. GO (Gene Ontology) annotation and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis of these DEGs revealed that these DEGs participate a variety of biological processes including osmoregulation, cytoskeleton organization, cell survival and death, and substantially modulate cell proliferation and embryonic development. In summery, RNA-seq methodology was applied for the first time to demonstrate hypotonic-induced transcriptomic alteration in oyster zygotes. Our findings not only interpreted the relatively high mortality of induced larvae, but also provided a valuable reference for further investigations on the mechanism of hyposaline induction, thus should aid to the application of low salinity in triploid induction in large scale aquaculture in future. | Transcriptomic Analysis of Pacific Oyster (Crassostrea gigas) Zygotes Under Hypotonic Triploid Induction | 10.1007/s11802-021-4450-8 |
2021-02-01 | The purpose of this study is to investigate the presence of nervous fibers and expression of TRP channels in samples harvested during decompressive/fusion spine surgeries from patients affected by chronic low back pain (CLBP). The aim was to understand if members of this family of receptors played a role in detection and processing of painful stimuli, to eventually define them as potential targets for CLBP alleviation. Expression of transient receptor potential (TRP) channels (A1, V1, V2, V4, and M8) was evaluated in samples from different periarticular sites of 6 patients affected by CLBP, at both protein and transcript levels. The capsular connective pathological tissue appeared infiltrated by sensitive unmyelinated nervous fibers. An increase in TRP channel mRNAs and proteins was observed in the pathological capsule compared with tissues collected from the non-symptomatic area in five of the six analyzed patients, independently by the location and number of affected sites. In particular, TRPV4 and TRPM8 were consistently upregulated in pathological tissues. Interestingly, the only patient showing a different pattern of expression also had a different clinical history. TRPV4 and TRPM8 channels may play a role in CLBP and warrant further investigations as possible therapeutic targets. | TRPV4 and TRPM8 as putative targets for chronic low back pain alleviation | 10.1007/s00424-020-02460-8 |
2021-02-01 | Nitrogen (N) deficiency is one of the factors limiting crop productivity worldwide. As major forms of N, nitrate (NO 3 − ) and ammonium (NH 4 + ) regulate plant growth as signals. Although there are abundant studies on the response of many plants to N stress, the mechanism by which wheat ( Triticum aestivum L.) roots adapt to low N, especially to low-NH 4 + stress, has not been fully elucidated. In this study, wheat seedlings were planted in 1/2-strength Hoagland’s solution containing 5 mM NO 3 − , 0.1 mM NO 3 − , or 0.1 mM NH 4 + to characterize root physiological responses to N deficit. Under low-N stress, root fresh weight, lateral root number increased compared with those under control conditions. Moreover, the concentrations of indole-3-acetic acid (IAA), cytokinins (CKs), gibberellin (GA 3 ), and jasmonic acid (JA) increased, while the salicylic acid (SA) concentration decreased under low-N stress. Assays using enzyme-linked immunosorbent assay (ELISA) and non-invasive micro-test technology (NMT) showed that H + -ATPase activity, the H + efflux, and the IAA influx increased, while N influx decreased under low-N stress. Further study revealed that low-NO 3 − stress increased nitrate reductase and glutamine synthetase activities, while low-NH 4 + stress increased the activities of glutamine synthetase and glutamate synthase. In conclusion, low-N stress altered root IAA, CKs, GA 3 , JA, and SA concentrations; increased H + -ATPase activity and H + efflux; promoted an increase in lateral root number and thus N absorption area. Besides, low-N stress increased the activities of key enzymes related to N assimilation, promoted protein biosynthesis, and ultimately enhanced root growth. | Low-Nitrogen Stress Stimulates Lateral Root Initiation and Nitrogen Assimilation in Wheat: Roles of Phytohormone Signaling | 10.1007/s00344-020-10112-5 |
2021-02-01 | Abstract The results of a study of the unoccupied electronic states of ultrathin films of bis-carboxyphenyl-phthalide (DCA-DPP) and bis-methylphenyl-phthalide (DM-DPP) up to 8 nm thick are presented. The studies are carried out by total current spectroscopy (TCS) in the energy range from 5 to 20 eV above E F during thermal vacuum deposition of these organic films on the surface of highly ordered pyrolytic graphite (HOPG). The values of E vac relative to E F , i.e., the work function of electrons of the DM-DPP films at a film thickness of 5–8 nm are found to be 4.3 ± 0.1 eV. The values of the work function of electrons of the DCA‑DPP films are found to be 3.7 ± 0.1 eV. The structure of the maxima of unoccupied electronic states of DCA-DPP and DM-DPP films in the studied energy range is established. A comparison of the obtained properties of DCA-DPP and DM-DPP films with the properties of films of molecules of unsubstituted diphenylphthalide (DPP) is presented. Thus, the –CH 3 substitution of the DPP molecule has almost no effect on the height of the potential barrier between the film and the HOPG surface, while –COOH substitution of the DPP molecule leads to an increase in the height of the potential barrier between the film and the HOPG substrate surface by 0.5–0.6 eV. Substitution of DPP molecules with –COOH functional groups and, thus, the formation of DCA-DPP molecules lead to a shift of two maxima of the fine structure of the total current spectra located at energies in the range from 5 to 8 eV above E F by about 1 eV towards the lower electron energies. | Unoccupied Electronic States and Potential Barrier in Films of Substituted Diphenylphthalides on the Surface of Highly Ordered Pyrolytic Graphite | 10.1134/S1063783421020104 |
2021-02-01 | Although the thin-blade strain ( HR-5 ) of Pyropia haitanensis could be cultivated in the south coast of China, the effect of low-salt tolerance on it is not clear. In this study, the conchospores and blades of the wild cultivated strain ( WT-10 ) of P. haitanensis and HR-5 strain were cultured in media with salinity of 26‰, 10‰, and 3‰, respectively. The results illustrated that: After being cultured for 7 days, the survival percentages of conchospores were not significantly different between WT-10 and HR-5 at the salinity of 26‰ and 10‰ ( P > 0.05), but the survival percentage was 60.8% higher in the latter than in the former at the salinity of 3‰ ( P < 0.01). When the 25-day-old blades of WT-10 and HR-5 were cultured at the salinity of 26‰, 10‰, and 3‰ for another 20 days, the specific growth rates of the blades length in HR-5 were similar to WT-10 , respectively. The contents of total phycobiliprotein of the HR-5 were 127.9, 88.7, and 83.0 mg/g, respectively, which were 1.8, 1.7, and 2.1 times those of the WT-10 , showing highly significant differences ( P < 0.01). In addition, with the decrease of culture salinity, the Fv/Fm values of WT-10 and HR-5 gradually decreased, but the reduction rate between the two strains was not significantly different ( P > 0.05). The above results indicated that the low-salt tolerance of conchospores and blades of HR-5 was not weaker than that of WT-10 , which provided a theoretical basis for the management mode when continuous precipitation was encountered in the cultivation process of HR-5 strain. | Low-salt tolerance of the thin-blade strain in Pyropia haitanensis | 10.1007/s10499-020-00637-7 |
2021-02-01 | China plans to pursue low-carbon development in its low-carbon pilot cities to control greenhouse gas emissions. The low-carbon city development is an important method to achieve sustainable development strategy, while it is also a new city development mode to promote natural ecology, low-carbon economy and social happiness. However, the evaluation process of the low-carbon city is a multiple objective and decision problem. A single indicator cannot comprehensively and objectively evaluate a city’s low-carbon development level, so a comprehensive evaluation index system should be established. So taking Guiyang as a case study, this article constructs 35 evaluating indicators that are based on the basic urban development level and low-carbon urban development level to analyse the economic development, social progress and environmental quality transmutation comprehensively by using the entropy method. The results show that in the whole process of sustainable development, the economic development, social progress and the environmental quality have been greatly improved, but the low-carbon level had been on the low side from 2003 to 2016 in Guiyang. Therefore, Guiyang still has a long way to go to become a low-carbon city, and concrete policies and countermeasures should be taken to promote the low-carbon level. In particular, Guiyang has to strengthen the dual constraint of carbon emission intensity and total carbon emissions, adhere to the development path characterized by low carbon and strive to achieve leapfrog development. | Research on the sustainable development process of low-carbon pilot cities: the case study of Guiyang, a low-carbon pilot city in south-west China | 10.1007/s10668-020-00679-0 |
2021-02-01 | The effects of low molecular weight organic acids (LMWOAs) on the adsorption of quinclorac by sepiolite were investigated using laboratory batch technique. Experiments were conducted with two natural sepiolite samples with different crystal structures and chemical compositions and high-purity sepiolite. The LMWOAs used were acetic, oxalic, and citric acid. And the adsorption mechanism was characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Our analysis revealed that adsorption of quinclorac on α-sepiolite and β-sepiolite was inhibited in the presence of 4 mmol L −1 LMWOAs, whereas LMWOAs stimulated the adsorption of quinclorac in the high-purity sepiolite. Inhibition or stimulation varied across the different types of organic acids. The adsorption isotherms in the presence of 4 mmol L −1 LMWOAs were better explained by Freundlich and linear model. The effect of organic acid concentrations (0–32 mmol L −1 ) on the adsorption of quinclorac by the three sepiolite samples varies greatly depending on the type of organic acid and the property of sepiolite. FTIR, XRD, and XPS analyses showed that LMWOAs bound strongly to the Si–O bond structure, and Si–O-quinclorac-acetic acid (oxalic acid or citric acid) was formed on the surface of β-sepiolite. The adsorption of quinclorac by β-sepiolite was via hydrogen bond, complexation reactions, and charge transfer in the presence of LMWOAs. These results indicate that LMWOAs affect quinclorac adsorption through various interactions involving competition, electrostatic attraction, bridging action, and hydrogen bonding. | Effects of low molecular weight organic acids on adsorption of quinclorac by sepiolite | 10.1007/s11356-020-11405-8 |
2021-02-01 | A new type of polyhalite potassium ore (NTPPO) was found in the Lower Triassic Jialingjiang Formation, NE Sichuan Basin, SW China. It is water soluble, therefore can be exploited using the water-solution method, and is of great potential of economic value and research significance. Based on cores, thin sections, energy spectrum and SEM analyses, its microfeatures, macrofeatures and origin are discussed, and a genetic model is established to provide a scientific basis for future evaluation, prediction and exploration of potassium ore in the Sichuan Basin. It is proposed that the NTPPO was caused by storm activities: (1) the storm broke the original sedimentary polyhalite–gypsum beds, whose fragments were transported into the salt basin with high content of K + and Mg 2+ ; (2) in the basin, the polyhalite continued to be formed from gypsum by metasomatism with K- and Mg-rich brine; (3) during diagenesis, under high temperature and high pressure, K–Mg-rich brine from halite continued to replace anhydrite (or gypsum) to form polyhalite. | Characteristics and origin of a new type of polyhalite potassium ore in the Lower Triassic Jialingjiang Formation, Puguang area, northeastern Sichuan Basin, SW China | 10.1186/s42501-021-00083-3 |
2021-02-01 | In the NW of the Iberian Peninsula, in the region of Lugo, a very exclusive Cambrian phyllite has been quarried and used for construction since prehistoric times, the Filita Verde or green phyllite. There are three varieties of this stone, all of them with the characteristic glitter of phyllites given by the metamorphic recrystallization of the phyllosilicates. Most of the architectural heritage of the area was built with this stone, which is currently being exported abroad. Its exceptional aesthetic and constructional characteristics have been historically used to build fortified settlements ( Castros ) by ancient pre-Roman cultures and also to construct churches and other ecclesiastic buildings during the middle age. Nowadays it is highly appreciated by architects. Because of these facts, this stone is a good candidate for the designation as a Global Stone Heritage Resource. | The Relevance of the Green Phyllites of Lugo (Spain) in the Architectonical Heritage: an Exceptional Roofing Slate Resource | 10.1007/s12371-021-00537-z |
2021-02-01 | In this paper, a fully integrated sub threshold LC voltage controlled oscillator (VCO) is presented. A design methodology is also proposed to find the optimal parameters lowering the power consumption. This methodology has been applied to design oscillators for different frequency bands. Furthermore, an adaptive body biasing technique has been used to improve the startup constrains and allows a high immunity to PVT (process, voltage and temperature) variations . A VCO operating in 5 GHz ISM (Industrial, Scientific and Medical) band has been realized with the proposed methodology in 0.13 μm CMOS. It consumes only 468 μW from 0.39 V supply voltage. This makes it possible to meet the required specifications of autonomous connected objects and IoT applications. The measured oscillation frequency can be tuned from 5.14 to 5.44 GHz. The obtained phase noise is approximately equal to − 112 dBc/Hz in post-layout simulation (PLS) and − 104.5 dBc/Hz in measure. | Ultra-low-power wideband NMOS LC-VCO design for autonomous connected objects | 10.1007/s10470-020-01613-0 |
2021-02-01 | Crypthecodinium cohnii growth was studied on pure carbon sources (glucose, acetate, glycerol) and low-cost complex carbon sources (sugarcane molasses, crude glycerol and vinegar effluent) for lipid and DHA production. Among the pure substrates, glucose induced the highest lipid content (14.75% w/w DCW) and DHA content (7.14 mg g −1 DCW). Among the low-cost substrates, the highest lipid and DHA content were observed for the crude glycerol assay (14.7% w/w DCW and 6.56 mg g −1 , respectively). Molasses induced the highest proportion of DHA of total fatty acids (49.58% w/w TFA) among all the substrates studied. Flow cytometric analysis revealed that the vinegar effluent induced the highest proportion of C. cohnii cells with injured membrane (92.8%). These results foresee the possibility of using these low-cost substrates at a larger scale for C. cohnii DHA and biodiesel production, aiming at zero wastes and process costs reduction. | Evaluating low-cost substrates for Crypthecodinium cohnii lipids and DHA production, by flow cytometry | 10.1007/s10811-020-02304-z |
2021-02-01 | Foamed and energized fluids fracturing has been used in both conventional and unconventional reservoirs, as they reduce the amount of water used and hence minimize deleterious impact on water-sensitive formations. They also aid in the flow back after treatment in reservoirs where drawdown is limited. In this paper, the most important foam properties are presented, in addition, when to use energized fluids fracturing and how to choose the best energizing component with the best quality. The impact of N 2 -energized fluids fracturing (NEF) on wells that were previously fractured using conventional fracturing fluids is also presented. In addition, a comparison between the results of N 2 -energized fluids fractured and conventional fluid fractured wells is presented. The effect of using 20 to 50% (NEF) on production through surface well testing and live production data showed excellent and sustainable production rates. An economical study is presented through comparing the total capital cost of both NEF and conventional fluids fracturing, in addition to the hydrocarbon recovery of wells after both types. Data considered in this work represent about 40 wells fractured using NEF in the Egyptian Western Desert. | Improving hydraulic fracturing effectiveness in depleted and low-pressure reservoirs using N2-energized fluids | 10.1007/s13202-020-01060-7 |
2021-02-01 | Deep learning is the fastest growing field in artificial intelligence and has led to many transformative innovations in various domains. However, lack of interpretability sometimes hinders its application in hypothesis-driven domains such as biology and healthcare. In this paper, we propose a novel deep learning model with individual feature ranking. Several simulated datasets with the scenarios that contributing features are correlated and buried among non-contributing features were used to characterize the novel analysis approach. A publicly available clinical dataset was also applied. The performance of the individual level dropout feature ranking model was compared with commonly used artificial neural network model, random forest model, and population level dropout feature ranking model. The individual level dropout feature ranking model provides a reasonable prediction of the outcomes. Unlike the random forest model and population level dropout feature ranking model, which can only identify global-wise contributing features (i.e., at population level), the individual level dropout feature ranking model allows further identification of impactful features on response at individual level. Therefore, it provides a basis for clustering patients into subgroups. This may provide a new tool for enriching patients in clinical drug development and developing personalized or individualized medicine. | A novel approach for personalized response model: deep learning with individual dropout feature ranking | 10.1007/s10928-020-09724-x |
2021-02-01 | A turbine disk design based on uncertainty quantifies the risks and improves the structural reliability. An optimized design issue related to turbine disk fatigue life reliability with subjective and objective multi-source uncertainties is a three-layer nested analysis process, where each iterative step requires a double-layer nested analysis containing probability and improbability. A self-evolution game model is proposed to solve the efficiency problem of the optimized design issue under a specific accuracy requirement. In the initial state, only a few sample points are needed to start the game. In the process of its evolution, the most valuable points are searched automatically, and performance functions are identified only at the points where the game diverges. The maximum failure probability is obtained after game consistency is achieved. Accuracy and efficiency are verified with typical numerical examples. The method is adopted to analyze the hybrid low cycle fatigue reliability of a real turbine disk. It is found that, owing to the elimination of an unnecessary artificial distribution hypothesis, the reliability is lower under the same safety life, and the results are more in line with engineering practice. | Calculation of hybrid reliability of turbine disk based on self-evolutionary game model with few shot learning | 10.1007/s00158-020-02734-w |
2021-02-01 | Abstract In shrimp aquaculture, manufactured diets that include various supplements and alternative fishmeal ingredients are increasingly being used and their effect on the gastrointestinal (GI) microbiota studied. However, dietary effects on different shrimp GI samples are not known. We investigated how a high (HFM) or low (LFM) fishmeal diet affects bacterial communities from different sample types collected from Penaeus monodon gastrointestinal tract. Bacterial communities of the stomach, intestine tissue and intestine digesta were assessed using 16s rRNA gene sequencing. The feed pellets were also assessed as a potential source of bacteria in the GI tract. Results showed substantial differences in bacterial communities between the two diets as well as between the different sample types. Within the shrimp GI samples, stomach and digesta communities were most impacted by diet, while the community observed in the intestine tissue was less affected. Proteobacteria , Firmicutes and Bacteroidetes were the main phyla observed in shrimp samples, with enrichment of Bacteroidetes and Firmicutes in the LFM fed shrimp. The feed pellets were dominated by Firmicutes and were largely dissimilar to the shrimp samples. Several key taxa were shared however between the feed pellets and shrimp GI samples, particularly in the LFM fed shrimp, indicating the pellets may be a significant source of bacteria observed in shrimp GI samples. In summary, both diet and sample type influenced the bacterial communities characterised from the shrimp GI tract. Thus, it is important to consider the sample type collected from the GI tract when investigating dietary impacts on gut bacterial communities in shrimp. Key points • Shrimp gastrointestinal communities are influenced by diet and sample type. • The low fishmeal diet enriched bacteria that aid in polysaccharide metabolism. • Feed pellets can be a source of bacteria-detected gastrointestinal tract of shrimp. | Effect of sample type and the use of high or low fishmeal diets on bacterial communities in the gastrointestinal tract of Penaeus monodon | 10.1007/s00253-020-11052-6 |
2021-02-01 | We studied the effects of low-dose ozone therapy on the sleep quality of patients with coronary heart disease (CHD) and insomnia by measuring the levels of brain-derived neurotrophic factor (BDNF) and GABA in blood serum. The 3-month course of low-dose ozone therapy significantly elevated serum BDNF and GABA in CHD patients with insomnia and improved parameters of anxiety, depression, and sleep quality according to Hospital Anxiety and Depression Scale (HADS), Pittsburgh Sleep Quality Index (PSQI), and Self-Rating Scale of Sleep (SRSS). Ozone therapy also significantly ( p <0.05) improved the total antioxidant status of the body by elevating catalase activity and reducing malondialdehyde and 8-OHdeoxyguanosine in the saliva. The serum levels of BDNF and GABA negatively and closely correlated with PSQI and HADS scores. Low-dose ozone therapy improved sleep quality and reduced PSQI and HADS scores due to up-regulation of BDNF and GABA. | Low-Dose Ozone Therapy Improves Sleep Quality in Patients with Insomnia and Coronary Heart Disease by Elevating Serum BDNF and GABA | 10.1007/s10517-021-05095-6 |
2021-02-01 | Introduction Inguinal hernias are among the most common surgical diseases in Africa. The current International HerniaSurge Guidelines recommend mesh-based surgical techniques in Low Resource Settings (LRS). This recommendation is currently unachievable in large parts of Africa due to the unaffordability of mesh and lack of appropriate training of the few available surgeons. There is, therefore, a need for formal training in mesh surgery. There is an experience in Hernia Repair for the Underserved in Central and South America, however, inadequate evidence of structured training in Africa. Material and methods Since 2016, the aid Organizations, Surgeons for Africa and Operation Hernia have developed and employed a structured hernia surgical training program for postgraduate surgical trainees and medical doctors in Rwanda. This course consists of lectures on relevant aspects of hernia surgery and hands-on training in operating theatres. The lectures emphasize anatomy and surgical technique. All parts of the training were evaluated. Formal pre-course evaluation was conducted to assess the personal surgical experience of the trainees. Results Over a 3-year period, a structured hernia training programme was employed to train a total of 36 surgical trainees in both mesh and also non mesh hernia surgery. The key principle in this course is the continuous competence assessment and feedback. Evidence is provided to demonstrate improvement in surgical skills as well as knowledge of surgical anatomy which is essential to acquiring surgical competency. With self-assessment, expressed on a Likert scale, the participants could improve the theoretical knowledge about hernias from median 4.4 (on a scale of 1–10) before training to 8.4 after the training. The specific knowledge about anatomy could be improved in the same assessment from 4.8 before training to 8.1. after the training. After training course 12 of the 36 participants (33.33%) were able to carry out both suture- and mesh-based operations of simple inguinal hernias completely and independently. 20 of the 36 participants (55.55%) required only minimal supervision and only four participants (11.11%) required surgical supervision even after the completion of the course. Conclusion We have demonstrated that, medical personnel in Africa can be trained in mesh and non-mesh hernia surgery using a structured training programme. | Improving surgical education in East Africa with a standardized hernia training program | 10.1007/s10029-020-02157-y |
2021-02-01 | The aim of the present study was to investigate the influence of low-level red (660 nm) and infrared (780 nm) laser with four different radiance exposures on human umbilical vein endothelial cells (HUVECs) in vitro . HUVECs (1.5 × 10 4 ) were incubated in 96-well culture plates. The cells were maintained in M199 medium supplemented with 20% fetal bovine serum, 1% antibiotic (penicillin), 1% anti-mycotic (Fungizone), and 1% endothelial cell growth supplement. After centrifugation, irradiations (660/780 nm, 40 mW, 1, 5, 10, and 20 J/cm 2 , 1 s, 5 s, 10 s, and 20 s, respectively, total energy 0.4 J, 2 J, 4 J, and 8 J, and beam spot size at target 0.04 cm 2 ) were performed at the bottom of Falcon tubes such that the laser beam directly reached the cell without passing through the culture medium. The cells were divided into groups based on radiant exposures. Cell viability and protein concentration were verified after 1, 2, 3, 6, 8, and 10 days. Red laser increased the cell viability and protein concentration in all groups (three-way ANOVA, p < 0.05) beginning on the second day. The greatest peak compared with the control was found when the radiant exposure was 5 J/cm 2 and 10 J/cm 2 . Infrared laser inhibited cell viability and modulated the protein concentration in the cells, with the highest peak protein concentration found on the second day in the group with radiant exposure of 1 J/cm 2 and 10 J/cm 2 (three-way ANOVA, p < 0.05). Red laser increased the viability and concentration of total proteins in HUVECs, whereas infrared laser had an inhibitory effect on cell viability, while maintaining the total protein concentration similar to that found in the control group. | Photobiomodulation alters the viability of HUVECs cells | 10.1007/s10103-020-03016-z |
2021-02-01 | The paper presents the adhesive strength measurements of the Ni–Cu surface alloy formed on a copper substrate at a different thickness of the transition layer. The formation of the surface alloy is provided by the low-energy high-current electron beam of a microsecond duration; the different thickness of the transition layer is varied by the thickness of the nickel film sputtered. The multiple deposition-irradiation process is performed during one vacuum cycle. It is found that the cross-section of the film (Ni)-substrate (Cu) interface is rather developed and curved. The transition layer thickness reduces with increasing thickness of the deposited nickel film. Scratch testing shows that the adhesive strength of the Ni–Cu surface alloy obtained by using the low-energy high-current electron beam, is higher than that of the sputter-deposited surface alloy. The highest adhesion is observed for the Ni–Cu surface alloy obtained by the nickel film deposition 0.125 μm thick. In this case, the crack formation and localized film delamination occur under the critical loads of 15 and 17 N, respectively. Nevertheless, a complete delamination of the surface alloy is not observed. | Adhesive Strength of Ni–Cu Surface Alloy Formation by Low-Energy High-Current Electron Beam | 10.1007/s11182-021-02237-1 |
2021-02-01 | The product of Aoc3 gene is known as vascular adhesion protein-1 (VAP-1), a glycoprotein contributing to leukocyte extravasation and exhibiting semicarbazide-sensitive amine oxidase activity (SSAO). Regarding the immune functions of VAP-1/SSAO, it is known that mice bearing Aoc3 gene knock-out (AOC3KO) exhibit defects in leukocyte migration similar to those of mice expressing a mutated VAP-1 lacking functional SSAO activity (knock-in, AOC3KI). However, it has not been reported whether these models differ regarding other disturbances. Thus, we further compared endocrine-metabolic phenotypes of AOC3KO and AOC3KI mice to their respective control. Special attention was paid on adiposity, glucose and lipid handling, since VAP-1/SSAO is highly expressed in adipose tissue (AT). In both mouse lines, no tissue SSAO activity was found, while Aoc3 mRNA was absent in AOC3KO only. Although food consumption was unchanged, both AOC3KO and AOC3KI mice were heavier and fatter than their respective controls. Other alterations commonly found in adipocytes from both lines were loss of benzylamine insulin-like action with unchanged insulin lipogenic responsiveness and adiponectin expression. A similar downregulation of inflammatory markers ( CD45 , IL6 ) was found in AT. Glucose handling and liver mass remained unchanged, while circulating lipid profile was distinctly altered, with increased cholesterol in AOC3KO only. These results suggest that the lack of oxidase activity found in AOC3KI is sufficient to reproduce the metabolic disturbances observed in AOC3KO mice, save those related with cholesterol transport. Modulation of SSAO activity therefore constitutes a potential target for the treatment of cardiometabolic diseases, especially obesity when complicated by low-grade inflammation. | Obesity of mice lacking VAP-1/SSAO by Aoc3 gene deletion is reproduced in mice expressing a mutated vascular adhesion protein-1 (VAP-1) devoid of amine oxidase activity | 10.1007/s13105-020-00756-y |
2021-02-01 | The low-voltage compact gyrotron is suitable for industrial applications. However, the beam-wave interaction efficiency is low in conventional low-voltage gyrotron. To improve the whole tube efficiency, a compact depressed collector is introduced in developing a 75 GHz low-voltage compact gyrotron. The compact depressed collector is directly connected to the output waveguide. It is grounded and isolated with the cavity by a ceramic ring which is easy to be connected with the application system. The design of the original tube electron beam voltage and electron beam current are 10 kV and 1.2 A. In the particle-in-cell (PIC) simulation, the operating mode is TE 0,1 and the generated power is 1.2 kW operated at the frequency of 75.5 GHz, which corresponds to an electron efficiency of 10%. When the depressed collector is performed and the electron reflux is under 5%, the efficiency of the whole tube can reach 30%, and when the reflux rate is controlled at about 15%, the efficiency of the whole tube can reach 50%. The dissipation power would be sufficiently reduced. | Study on a Depressed Collector for a 75 GHz Low-Voltage Compact Gyrotron for Industrial Application | 10.1007/s10762-020-00761-8 |
2021-02-01 | The aim of this study is to conduct a narrative review of the literature emphasizing current models of non-specific low back and neck pain with an emphasis on chronic and disabling pain. We include its risk factors, etiology, pathophysiology, and differential diagnosis. Emphasis is also placed on variables of chronification and the persistence of this type of pain. Our secondary aim was to provide foundational knowledge before advancing the discussion to a proposal of evidence-based management strategies for patients suffering from chronic primary spine pain in a subsequent follow-up article. A review of the English medical literature was performed using search terms “chronic low back pain” OR “chronic neck pain” AND “primary,” “differential diagnosis,” “pathophysiology,” “functional imaging” and “risk factors.” Additional searches were made using Google Scholar and PubMed search engines through January 17, 2020. A total of 112 articles were used. Acute and chronic spine pain differ significantly in risk factors, pathophysiology, prevalence, and differential diagnosis. Chronic spinal pain is multifactorial in nature, and that proposed causes of chronicity and pain-related disability span the entire spectrum of the biopsychosocial domain. Chronic low back and neck pain poses a significant global threat of disabling and burdensome quality of life. Because pain is a complex multifactorial integrative experience, the scientific literature reports an abundance of multidimensional risk factors associated with the persistence of pain beyond normal healing times. Understanding the nature of chronic primary spinal pain will provide clinicians with necessary and valuable insights for patient care along the complex and variable spectrum of the biopsychosocial approach. | Chronic Primary Pain of the Spine: an Integrative Perspective Part 1 | 10.1007/s42399-021-00772-z |
2021-01-30 | Herein, copper oxide/copper sulfide (CuO/Cu x S) composites have been prepared by treating CuO with thiourea by an aqueous hydrothermal route and their thermoelectric properties are studied. The electrical conductivity is improved with the increase in thiourea content, as a result, thermoelectric power factor increased from 10 –4 to 10 1 µW m −1 K −2 , and thermal conductivity of the CuO is also found to decrease with thiourea treatment. A detailed analysis indicated that these changes are due to the formation of copper sulfide (Cu x S) in the CuO compound; a small fraction of electrically good conducting Cu x S in the bulk CuO has produced composites with better electrical conductivity. These low-cost and non-toxic materials can be useful in thermoelectric energy conversion applications. | CuO/CuxS composites fabrication and their thermoelectric properties | 10.1007/s40243-021-00189-7 |
2021-01-29 | We have carried out ground-based NIRAS (Near-InfraRed Aurora and airglow Spectrograph) observations at Syowa station, Antarctic ( $$69.0^{\circ }\text {S}$$ 69 . 0 ∘ S , $$39.6^{\circ }\text {E}$$ 39 . 6 ∘ E ) and Kiruna ( $$67.8^{\circ }\text {N}$$ 67 . 8 ∘ N , $$20.4^{\circ }\text {E}$$ 20 . 4 ∘ E ), Sweden for continuous measurements of hydroxyl (OH) rotational temperatures and a precise evaluation of auroral contaminations to OH Meinel (3,1) band. A total of 368-nights observations succeeded for 2 winter seasons, and 3 cases in which $$\text {N}_2^+$$ N 2 + Meinel (1,2) band around $$1.5\,\mu \text {m}$$ 1.5 μ m was significant were identified. Focusing on two specific cases, detailed spectral characteristics with high temporal resolutions of 30 s are presented. Intensities of $$\text {N}_2^+$$ N 2 + band were estimated to be 228 kR and 217 kR just at the moment of the aurora breakup and arc intensification during pseudo breakup, respectively. At a wavelength of $$\text {P}_1(2)$$ P 1 ( 2 ) line ( $$\sim 1523 \,\text {nm}$$ ∼ 1523 nm ), $$\text {N}_2^+$$ N 2 + emissions were almost equal to or greater than the OH line intensity. On the other hand, at a wavelength of $$\text {P}_1(4)$$ P 1 ( 4 ) line ( $$\sim 1542 \,\text {nm}$$ ∼ 1542 nm ), the OH line was not seriously contaminated and still dominant to $$\text {N}_2^+$$ N 2 + emissions. Furthermore, we evaluated $$\text {N}_2^+$$ N 2 + (1,2) band effects on OH rotational temperature estimations quantitatively for the first time. Auroral contaminations from $$\text {N}_2^+$$ N 2 + (1,2) band basically lead negative bias in OH rotational temperature estimated by line-pair-ratio method with $$\text {P}_1(2)$$ P 1 ( 2 ) and $$\text {P}_1(4)$$ P 1 ( 4 ) lines in OH (3,1) band. They possibly cause underestimations of OH rotational temperatures up to 40 K. In addition, $$\text {N}_2^+$$ N 2 + (1,2) band contaminations were temporally limited to a moment around the aurora breakup. This is consistent with proceeding studies reporting that enhancements of $$\text {N}_2^+$$ N 2 + (1,2) band were observed associated with International Brightness Coefficient 2–3 auroras. It is also suggested that the contaminations would be neglected in the polar cap and the sub-auroral zone, where strong aurora intensification is less observed. Further spectroscopic investigations at these wavelengths are needed especially for more precise evaluations of $$\text {N}_2^+$$ N 2 + (1,2) band contaminations. For example, simultaneous 2-D imaging observation and spectroscopic measurement with high spectral resolutions for airglow in OH (3,1) band will make great advances in more robust temperature estimations in the auroral zone. | Temporal evolutions of
$$\text {N}_2^+$$
N
2
+
Meinel (1,2) band near
$$1.5.\,\upmu \text {m}$$
1.5
.
μ
m
associated with aurora breakup and their effects on mesopause temperature estimations from OH Meinel (3,1) band | 10.1186/s40623-021-01360-0 |
2021-01-29 | Background Antibiotic exposure in term infants has been associated with later obesity. Premature, very-low-birth-weight (birth weight ≤ 1500 g) infants in the neonatal intensive care unit frequently are exposed to antibiotics. Our hypothesis was that in preterm infants, there is a positive linear and dose-dependent relationship between antibiotic exposure and growth from birth through 12 months’ corrected age. Methods Retrospective analysis of prospectively collected data of all antibiotic use among inborn, preterm (≤32 weeks’ gestation), very-low-birth-weight infants admitted to the neonatal intensive care unit at Parkland Memorial Hospital and followed in the Low Birth Weight Clinic at Children’s Medical Center, Dallas, TX. Antibiotic use was quantified by days of therapy which was compared with weight and length parameters at birth, 36 weeks’ postmenstrual age, and 2, 4, 6, and 12 months’ corrected age. The change in weight and length z-scores from birth to all subsequent age points was calculated. Stepwise multivariate regression analysis was performed to determine predictors of weight, length, and weight-for-length delta z-scores from birth to each subsequent age point. Results During the 18-month study, 161 infants received a median of 11 (IQR, 5.5–19.5) antibiotic days of therapy which was not associated with weight or length delta z-scores from birth through 12 months’ corrected age. Conclusion Association of prolonged antibiotic use and neonatal morbidities and mortality may override the potential association with increased weight gain in the NICU and beyond. | Antibiotic exposure and growth patterns in preterm, very low birth weight infants | 10.1186/s40748-021-00126-6 |
2021-01-28 | This paper aims to gain new insights into clastic buried hill reservoirs. For this purpose, the Permian sandstone reservoirs in the Upper Shihezi Formation, Gubei low buried hill, Jiyang Depression, was taken as the object. Referring to the evolution histories of reservoirs and tectonics, the diagenesis of the reservoirs and its coupling with tectonic activity were investigated, with the aid of techniques like core observation, casting sheet observation, scanning electron microscopy (SEM), cathode luminescence, electron probe, back scattering, fluid inclusion, and pore permeability tests. The results show that the Permian sandstone reservoirs in the Upper Shihezi Formation, Gubei low buried hill, Jiyang Depression, are low-porosity, low-permeability reservoirs with complex diagenesis. The diagenetic evolution sequence can be summarized as early feldspar corrosion/kaolinite cemention/early pyrite cemention→carbonate cemention/secondary enlargement of quartz→quartz corrosion/corrosion of quartz and its secondary enlargement→late calcite cemention→late pyrite cemention/carbonate corrosion/late feldspar corrosion/corrosion of dissolvable miscellaneous matrix; compaction effect exists throughout the evolution process. The reservoirs went through (I) shallow burial epidiagenesis, (II) near-surface hydrothermal diagenesis, (III) deep burial alkaline diagenesis, and (IV) continuous burial acid diagenesis. The diagenetic evolution of these four stages is significantly affected by tectonic activities, and the article lists the evidence that diagenesis is affected by tectonic activity. The research results lay the basis for the prediction and evaluation of the Permian sandstone reservoirs in the Upper Shihezi Formation, Gubei low buried hill, Jiyang Depression, and shed new light on the exploration of tight sandstone reservoirs. | Coupling between tectonic activity and diagenetic evolution of a clastic buried hill—a case study from Gubei low buried hill in Jiyang Depression of Bohai Bay Basin | 10.1007/s12517-021-06566-w |
2021-01-23 | Background Although school garden programs have been shown to improve dietary behaviors, there has not been a cluster-randomized controlled trial (RCT) conducted to examine the effects of school garden programs on obesity or other health outcomes. The goal of this study was to evaluate the effects of a one-year school-based gardening, nutrition, and cooking intervention (called Texas Sprouts) on dietary intake, obesity outcomes, and blood pressure in elementary school children. Methods This study was a school-based cluster RCT with 16 elementary schools that were randomly assigned to either the Texas Sprouts intervention ( n = 8 schools) or to control (delayed intervention, n = 8 schools). The intervention was one school year long (9 months) and consisted of: a) Garden Leadership Committee formation; b) a 0.25-acre outdoor teaching garden; c) 18 student gardening, nutrition, and cooking lessons taught by trained educators throughout the school-year; and d) nine monthly parent lessons. The delayed intervention was implemented the following academic year and received the same protocol as the intervention arm. Child outcomes measured were anthropometrics (i.e., BMI parameters, waist circumference, and body fat percentage via bioelectrical impedance), blood pressure, and dietary intake (i.e., vegetable, fruit, and sugar sweetened beverages) via survey. Data were analyzed with complete cases and with imputations at random. Generalized weighted linear mixed models were used to test the intervention effects and to account for clustering effect of sampling by school. Results A total of 3135 children were enrolled in the study (intervention n = 1412, 45%). Average age was 9.2 years, 64% Hispanic, 47% male, and 69% eligible for free and reduced lunch. The intervention compared to control resulted in increased vegetable intake (+ 0.48 vs. + 0.04 frequency/day, p = 0.02). There were no effects of the intervention compared to control on fruit intake, sugar sweetened beverages, any of the obesity measures or blood pressure. Conclusion While this school-based gardening, nutrition, and cooking program did not reduce obesity markers or blood pressure, it did result in increased vegetable intake. It is possible that a longer and more sustained effect of increased vegetable intake is needed to lead to reductions in obesity markers and blood pressure. Clinical trials number NCT02668744 . | School-based gardening, cooking and nutrition intervention increased vegetable intake but did not reduce BMI: Texas sprouts - a cluster randomized controlled trial | 10.1186/s12966-021-01087-x |
2021-01-21 | Background Chronic nonspecific low back pain (CNSLBP) troubles approximately 30% of people worldwide. Silver needle therapy (SNT) is a treatment method to relieve soft tissue pain through heating. Therefore, this study aimed to observe the effects of SNT on CNSLBP. Methods In this study, 100 patients were randomly divided into 2 groups: silver needle (SN) group and control group ( n = 50). In the SN group, patients received SNT and physiotherapy, while patients received physiotherapy alone in the control group. At the 6-month follow-up, the numerical rating scale (NRS), Oswestry Disability Index (ODI), Short-Form 12 of quality of life (SF-12), the natural logarithms of low-frequency measurement (InLF), and the natural logarithms of high-frequency measurement (InHF) of heart rate variability (HRV) were recorded. Results In both groups, NRS, ODI, SF-12 scores, and HRV at 2 weeks after treatment were improved and maintained for 6 months. Compared with the control group, more significant improvements were observed in the NRS and SF-12 scores at 1, 2, 3, and 6 months and in the ODI scores at 1 and 2 months in the SN group ( P < 0.05). However, there was no significant difference between the groups in the ODI scores at 3 and 6 months. InLF and InHF in the SN group were higher than those in the control group at 3 and 6 months ( P < 0.05). Conclusions SNT relieved pain and improved quality of life and autonomic nerve activity, especially parasympathetic nerve, in patients with CNSLBP, without serious complications. Trial registration Chinese Clinical Trial Registry No. ChiCTR-OOC-17013237 . Registered on November 11, 2017. | Efficacy of silver needle therapy for the treatment of chronic nonspecific low back pain: a prospective, single-center, randomized, parallel-controlled clinical trial | 10.1186/s13063-021-05040-y |
2021-01-20 | In the upcoming 5G and beyond systems, ultra-reliable and low latency communication (URLLC) has been considered as the key enabler to support diverse mission-critical services, such as industrial automation, remote healthcare, and intelligent transportation. However, the two stringent requirements of URLLC: extremely low latency and ultra-strict reliability have posed great challenges in system designing. In this article, the basic concepts and the potential applications of URLLC are first introduced. Then, the state-of-the-art research of URLLC in the physical layer, link layer and the network layer are overviewed. In addition, some potential research topics and challenges are also identified. | Ultra-reliable and low-latency communications: applications, opportunities and challenges | 10.1007/s11432-020-2852-1 |
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