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In normal fatigue-testing of smooth specimens, about 90 percent is spent in crack nucleation and only the remaining 10 percent in crack propagation. However, in corrosion fatigue crack nucleation is facilitated by corrosion; typically, about 10 percent of life is sufficient for this stage. The rest (90 percent) of life is spent in crack propagation. Thus, it is more useful to evaluate crack-propagation behavior during corrosion fatigue. | https://en.wikipedia.org/wiki/Corrosion_fatigue |
Fracture mechanics uses pre-cracked specimens, effectively measuring crack-propagation behavior. For this reason, emphasis is given to crack-propagation velocity measurements (using fracture mechanics) to study corrosion fatigue. Since fatigue crack grows in a stable fashion below the critical stress-intensity factor for fracture (fracture toughness), the process is called sub-critical crack growth. | https://en.wikipedia.org/wiki/Corrosion_fatigue |
The diagram on the right shows typical fatigue-crack-growth behavior. In this log-log plot, the crack-propagation velocity is plotted against the applied stress-intensity range. Generally there is a threshold stress-intensity range, below which crack-propagation velocity is insignificant. | https://en.wikipedia.org/wiki/Corrosion_fatigue |
Three stages may be visualized in this plot. Near the threshold, crack-propagation velocity increases with increasing stress-intensity range. In the second region, the curve is nearly linear and follows Paris' law(6); in the third region crack-propagation velocity increases rapidly, with the stress-intensity range leading to fracture at the fracture-toughness value. Crack propagation under corrosion fatigue may be classified as a) true corrosion fatigue, b) stress corrosion fatigue or c) a combination of true, stress and corrosion fatigue. | https://en.wikipedia.org/wiki/Corrosion_fatigue |
In normal gait, the small gluteal muscles on the stance side can stabilize the pelvis in the coronal plane. Weakness or paralysis of these muscles caused by a damaged superior gluteal nerve can result in a weak abduction in the affected hip joint. This gait disturbance is known as Trendelenburg gait. | https://en.wikipedia.org/wiki/Superior_gluteal_nerve |
In a positive Trendelenburg's sign the pelvis sags toward the normal unsupported side (the swing leg). The opposite, when the pelvis is elevated on the swing side, is known as Duchenne limp. Bilateral loss of the small gluteal muscles results in a waddling gait. | https://en.wikipedia.org/wiki/Superior_gluteal_nerve |
In normal gait, the vertical ground reaction force (GRF) plot has two peaks – one when the foot strikes the ground and the second peak is caused by push-off force from the ground. The shape of the vertical GRF signal is abnormal in PD. In the earlier stages of the disease, reduced forces (or peak heights) are found for heel contact and the push-off phase resembling that of elderly subjects. In the more advanced stages of the disorder where gait is characterized by small shuffling steps, PD patients show only one narrow peak in the vertical GRF signal. | https://en.wikipedia.org/wiki/Parkinsonian_gait |
In normal hearing, the majority of the auditory signals that reach the organ of Corti in the first place come from the outer ear. Sound waves enter through the auditory canal and vibrate the tympanic membrane, also known as the eardrum, which vibrates three small bones called the ossicles. As a result, the attached oval window moves and causes movement of the round window, which leads to displacement of the cochlear fluid. However, the stimulation can happen also via direct vibration of the cochlea from the skull. | https://en.wikipedia.org/wiki/Spiral_organ_of_Corti |
The latter is referred to as Bone Conduction (or BC) hearing, as complementary to the first one described, which is instead called Air Conduction (or AC) hearing. Both AC and BC stimulate the basilar membrane in the same way (Békésy, G.v., Experiments in Hearing. 1960). | https://en.wikipedia.org/wiki/Spiral_organ_of_Corti |
The basilar membrane on the tympanic duct presses against the hair cells of the organ as perilymphatic pressure waves pass. The stereocilia atop the IHCs move with this fluid displacement and in response their cation, or positive ion selective, channels are pulled open by cadherin structures called tip links that connect adjacent stereocilia. The organ of Corti, surrounded in potassium-rich fluid endolymph, lies on the basilar membrane at the base of the scala media. | https://en.wikipedia.org/wiki/Spiral_organ_of_Corti |
Under the organ of Corti is the scala tympani and above it, the scala vestibuli. Both structures exist in a low potassium fluid called perilymph. Because those stereocilia are in the midst of a high concentration of potassium, once their cation channels are pulled open, potassium ions as well as calcium ions flow into the top of the hair cell. With this influx of positive ions the IHC becomes depolarized, opening voltage-gated calcium channels at the basolateral region of the hair cells and triggering the release of the neurotransmitter glutamate. An electrical signal is then sent through the auditory nerve and into the auditory cortex of the brain as a neural message. | https://en.wikipedia.org/wiki/Spiral_organ_of_Corti |
In normal horses, ASIP restricts the production of eumelanin to the "points": the legs, mane, tail, ear edges, etc. In 2001, researchers discovered a recessive mutation on ASIP that, when homozygous, left the horse without any functional ASIP. As a result, horses capable of producing true black pigment had uniformly black coats. The dominant, wildtype allele producing bay is symbolized as A, while the recessive allele producing black is symbolized as a. Extension is epistatic over agouti and will cause chestnut coloration regardless of what agouti alleles are present. | https://en.wikipedia.org/wiki/Agouti_coloration_genetics |
In normal individuals, electrical activity in the heart is initiated in the sinoatrial (SA) node (located in the right atrium), propagates to the atrioventricular (AV) node, and then through the bundle of His to the ventricles of the heart. The AV node acts as a gatekeeper, limiting the electrical activity that reaches the ventricles of the heart. This function of the AV node is important, because if the signals generated in the atria of the heart were to increase in rate (as they do during atrial fibrillation or atrial flutter), the AV node will limit the electrical activity that conducts to the ventricles. For instance, if the atria are electrically activated at 300 beats per minute, half those electrical impulses are blocked by the AV node, so that the ventricles are activated at 150 beats per minute (giving a pulse of 150 beats per minute). | https://en.wikipedia.org/wiki/Junctional_ectopic_tachycardia |
Another important property of the AV node is that it slows down individual electrical impulses. This is manifest on the ECG as the PR interval, which is about less than 200 milliseconds, the time from activation of the atria (manifest as the P wave) and activation of the ventricles (manifest as the QRS complex).Individuals with JET have a "short-circuit" in their heart, where the electricity bypasses the AV node, causing the heart to beat faster than normal. The cause of the arrhythmia, the ectopic focus, is usually near the AV node in the triangle of Koch (a rough triangle with points at the coronary sinus, the tendon of Todaro, and the tricuspid valve).Patients of heart surgery may experience an accelerated narrow complex tachycardia, usually within the first 24–48 hours (but occasionally longer) after surgery. | https://en.wikipedia.org/wiki/Junctional_ectopic_tachycardia |
There may be atrio-ventricular disassociation with more ventricular signals than atrial signals. The cause of JET is felt to be due to manipulation of the tissue surrounding the AV node during surgery, however debate exists regarding the exact cause, as it is seen after procedures even without significant manipulation of this area.JET-like symptoms can also manifest congenitally and in the first six months of life. This syndrome, which may also referred to as His bundle tachycardia, is resistant to therapy and can be difficult to treat. | https://en.wikipedia.org/wiki/Junctional_ectopic_tachycardia |
In normal individuals, free light chains are rapidly cleared from the blood and catabolised by the kidneys. Monomeric free light chains are cleared in 2–4 hours, and dimeric light chains in 3–6 hours. Removal may be prolonged to 2–3 days in people with complete renal failure. Human kidneys are composed of approximately half a million nephrons. | https://en.wikipedia.org/wiki/Serum_free_light-chain_measurement |
Each nephron contains a glomerulus with basement membrane pores that allow filtration of immunoglobulin light chains and other small molecules from the blood into the proximal tubule of the nephron.Filtered molecules are either excreted in the urine or may be specifically re-absorbed. Protein molecules that pass through the glomerular pores are either absorbed unchanged (such as albumin), degraded in the proximal tubular cells and absorbed (such as free light chains), or excreted as fragments. This re-absorption is mediated by a receptor complex (megalin/cubulin) and prevents the loss of large amounts of protein into the urine. | https://en.wikipedia.org/wiki/Serum_free_light-chain_measurement |
It is very efficient and can process 10–30 g of low-molecular-weight proteins per day, so under normal conditions no light chains pass beyond the proximal tubules.If immunoglobulin light chains are produced in sufficient amounts to overwhelm the proximal tubules' absorption mechanisms (usually due to the presence of a plasma cell tumour) the light chains enter the distal tubules and can appear in the urine (Bence Jones protein). The passage of large amounts of immunoglobulin light chains through the kidneys may cause inflammation or blockage of the kidney tubules.The distal tubules of the kidneys secrete large amounts of uromucoid (Tamm–Horsfall protein). This is the dominant protein in normal urine and is thought to be important in preventing ascending urinary infections. | https://en.wikipedia.org/wiki/Serum_free_light-chain_measurement |
It is a relatively small glycoprotein (80 kDa) that aggregates into polymers of 20–30 molecules. It contains a short amino-acid sequence that can specifically bind to some free light chains. | https://en.wikipedia.org/wiki/Serum_free_light-chain_measurement |
Together they can form an insoluble precipitate which blocks the distal part of the nephrons. This is termed "cast nephropathy" or "myeloma kidney" and is typically found in patients with multiple myeloma. This can block the flow of urine causing the death of the respective nephrons. | https://en.wikipedia.org/wiki/Serum_free_light-chain_measurement |
Rising concentrations of light chains are filtered by the remaining nephrons leading to a cycle of accelerating renal damage with rising concentrations of free light chains in the blood. At the same time, the amount of free light chains entering the urine will be decreased and will be zero if the patient stops producing urine (anuria). Conversely, urine concentrations of free light chains could increase if renal function improved in a multiple myeloma patient receiving treatment. This could account for the poor correlation frequently seen when urine and serum free light-chain concentrations are compared.The 500 mg of FLCs produced per day by the normal lymphoid system, however, flows through the glomeruli and is completely processed by the proximal tubules. If the proximal tubules of the nephrons are damaged or stressed (such as in hard exercise), filtered FLCs may not be completely metabolised and small amounts may then appear in the urine. | https://en.wikipedia.org/wiki/Serum_free_light-chain_measurement |
In normal individuals, the AV node slows the conduction of electrical impulses through the heart. This is manifest on a surface electrocardiogram (ECG) as the PR interval. The normal PR interval is from 120 ms to 200 ms in length. | https://en.wikipedia.org/wiki/First-degree_atrioventricular_block |
This is measured from the initial deflection of the P wave to the beginning of the QRS complex.In first-degree heart block, the AV node conducts the electrical activity more slowly. This is seen as a PR interval greater than 200 ms in length on the surface ECG. It is usually an incidental finding on a routine ECG.First-degree heart block does not require any particular investigations except for electrolyte and drug screens, especially if an overdose is suspected. | https://en.wikipedia.org/wiki/First-degree_atrioventricular_block |
In normal individuals, there is a constant production of ketone bodies by the liver and their utilization by extrahepatic tissues. The concentration of ketone bodies in blood is maintained around 1 mg/dL. Their excretion in urine is very low and undetectable by routine urine tests (Rothera's test).When the rate of synthesis of ketone bodies exceeds the rate of utilization, their concentration in blood increases; this is known as ketonemia. This is followed by ketonuria – excretion of ketone bodies in urine. | https://en.wikipedia.org/wiki/Ketone_body |
The overall picture of ketonemia and ketonuria is commonly referred to as ketosis. The smell of acetoacetate and/or acetone in breath is a common feature in ketosis. When a type 1 diabetic suffers acute biological stress (infection, heart attack, or physical trauma) or fails to administer enough insulin, they may enter the pathological state of diabetic ketoacidosis. | https://en.wikipedia.org/wiki/Ketone_body |
Under these circumstances, the low or absent insulin levels in the blood, combined with the inappropriately high glucagon concentrations, induce the liver to produce glucose at an inappropriately increased rate, causing acetyl-CoA resulting from the beta-oxidation of fatty acids, to be converted into ketone bodies. The resulting very high levels of ketone bodies lower the pH of the blood plasma, which reflexively triggers the kidneys to excrete urine with very high acid levels. The high levels of glucose and ketones in the blood also spill passively into the urine (due to the inability of the renal tubules to reabsorb glucose and ketones from the tubular fluid, being overwhelmed by the high volumes of these substances being filtered into the tubular fluid). | https://en.wikipedia.org/wiki/Ketone_body |
The resulting osmotic diuresis of glucose causes the removal of water and electrolytes from the blood resulting in potentially fatal dehydration. Individuals who follow a low-carbohydrate diet will also develop ketosis. This induced ketosis is sometimes called nutritional ketosis, but the level of ketone body concentrations are on the order of 0.5–5 mM whereas the pathological ketoacidosis is 15–25 mM.The process of ketosis is currently being investigated for efficacy in ameliorating the symptoms of Alzheimer's disease and Angelman syndrome | https://en.wikipedia.org/wiki/Ketone_body |
In normal infants, AFP in CSF is: median 61 kIU/L (5th-95th centile: 2-889 kIU/L) in infants -69 to 31 days old median 1.2 kIU/L (5th-95th centile: 0.1-12.5 kIU/L) in infants 32 to 110 days oldLevels of AFP in CSF decline with gestational age in proportion to levels of AFP in serum | https://en.wikipedia.org/wiki/Elevated_alpha-fetoprotein |
In normal liver, stellate cells are described as being in a quiescent state. Quiescent stellate cells represent 5-8% of the total number of liver cells. Each cell has several long protrusions that extend from the cell body and wrap around the sinusoids. The lipid droplets in the cell body store vitamin A as retinol ester. | https://en.wikipedia.org/wiki/Ito_cell |
The function and role of quiescent hepatic stellate cells is unclear. Recent evidence suggests a role as a liver-resident antigen-presenting cell, presenting lipid antigens to and stimulating proliferation of NKT cells.When the liver is damaged, stellate cells can change into an activated state. The activated stellate cell is characterized by proliferation, contractility, and chemotaxis. | https://en.wikipedia.org/wiki/Ito_cell |
This state of the stellate cell is the main source of extracellular matrix production in liver injury. This attribute makes it a key factor in the pathophysiology of the liver. The amount of stored vitamin A decreases progressively in liver injury. | https://en.wikipedia.org/wiki/Ito_cell |
The activated stellate cell is also responsible for secreting collagen scar tissue, which can lead to cirrhosis. More recent studies have also shown that in vivo activation of hepatic stellate cells by agents causing liver fibrosis can eventually lead to senescence in these cells, marked by increased SA-beta-galactosidase staining, as well as p53 accumulation and activation of Rb—hallmarks of cellular senescence. Senescent hepatic stellate cells have been demonstrated to limit liver fibrosis by activating interactions with NK cells. Senescence of hepatic stellate cells could prevent progression of liver fibrosis, although this has not been implemented as a therapy, and would carry the risk of hepatic dysfunction. | https://en.wikipedia.org/wiki/Ito_cell |
In normal lymphoid tissue, recirculating resting B cells migrate through the FDC networks, whereas antigen-activated B cells are intercepted and undergo clonal expansion within the FDC networks, generating germinal centers (GC). FDCs are among main producers of the chemokine CXCL13 which attracts and organises lymphoid cells. | https://en.wikipedia.org/wiki/Follicular_dendritic_cells |
In normal metabolism, the elevated blood glucose instructs beta (β) cells in the Islets of Langerhans, located in the pancreas, to release insulin into the blood. The insulin makes insulin-sensitive tissues in the body (primarily skeletal muscle cells, adipose tissue, and liver) absorb glucose which provides energy as well as lowers blood glucose. The beta cells reduce insulin output as the blood glucose level falls, allowing blood glucose to settle at a constant of approximately 5 mmol/L (90 mg/dL). In an insulin-resistant person, normal levels of insulin do not have the same effect in controlling blood glucose levels. | https://en.wikipedia.org/wiki/Insulin_Resistance |
When the body produces insulin under conditions of insulin resistance, the cells are unable to absorb or use it as effectively and it stays in the bloodstream. Certain cell types such as fat and muscle cells require insulin to absorb glucose and when these cells fail to respond adequately to circulating insulin, blood glucose levels rise. The liver normally helps regulate glucose levels by reducing its secretion of glucose in the presence of insulin. | https://en.wikipedia.org/wiki/Insulin_Resistance |
However, in insulin resistance, this normal reduction in the liver's glucose production may not occur, further contributing to elevated blood glucose.Insulin resistance in fat cells results in reduced uptake of circulating lipids and increased hydrolysis of stored triglycerides. This leads to elevated free fatty acids in the blood plasma and can further worsen insulin resistance. Since insulin is the primary hormonal signal for energy storage into fat cells, which tend to retain their sensitivity in the face of hepatic and skeletal muscle resistance, insulin resistance stimulates the formation of new fatty tissue and accelerates weight gain.In states of insulin resistance, beta cells in the pancreas increase their production of insulin. | https://en.wikipedia.org/wiki/Insulin_Resistance |
This causes high blood insulin (hyperinsulinemia) to compensate for the high blood glucose. During this compensated phase of insulin resistance, beta cell function is upregulated, insulin levels are higher, and blood glucose levels are still maintained. If compensatory insulin secretion fails, then either fasting (impaired fasting glucose) or postprandial (impaired glucose tolerance) glucose concentrations increase. | https://en.wikipedia.org/wiki/Insulin_Resistance |
Eventually, type 2 diabetes occurs when glucose levels become higher as the resistance increases and compensatory insulin secretion fails. The inability of the β-cells to produce sufficient insulin in a condition of hyperglycemia is what characterizes the transition from insulin resistance to type 2 diabetes. Insulin resistance is strongly associated with intestinal-derived apoB-48 production rate in insulin-resistant subjects and type 2 diabetics. | https://en.wikipedia.org/wiki/Insulin_Resistance |
Insulin resistance often is found in people with visceral adiposity, hypertension, hyperglycemia, and dyslipidemia involving elevated triglycerides, small dense low-density lipoprotein (sdLDL) particles, and decreased high-density lipoprotein (HDL) cholesterol levels. With respect to visceral adiposity, a great deal of evidence suggests two strong links with insulin resistance. First, unlike subcutaneous adipose tissue, visceral adipose cells produce significant amounts of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-a), and Interleukins-1 and −6, etc. In numerous experimental models, these proinflammatory cytokines disrupt normal insulin action in fat and muscle cells and may be a major factor in causing the whole-body insulin resistance observed in patients with visceral adiposity. | https://en.wikipedia.org/wiki/Insulin_Resistance |
Much of the attention on production of proinflammatory cytokines has focused on the IKK-beta/NF-kappa-B pathway, a protein network that enhances transcription of inflammatory markers and mediators that may cause insulin resistance. Second, visceral adiposity is related to an accumulation of fat in the liver, a condition known as non-alcoholic fatty liver disease (NAFLD). The result of NAFLD is an excessive release of free fatty acids into the bloodstream (due to increased lipolysis), and an increase in hepatic breakdown of glycogen stores into glucose (glycogenolysis), both of which have the effect of exacerbating peripheral insulin resistance and increasing the likelihood of Type 2 diabetes mellitus.The excessive expansion of adipose tissue that tends to occur under sustainedly positive energy balance (as in overeating) has been postulated by Vidal-Puig to induce lipotoxic and inflammatory effects that may contribute to causing insulin resistance and its accompanying disease states.Also, insulin resistance often is associated with a hypercoagulable state (impaired fibrinolysis) and increased inflammatory cytokine levels. | https://en.wikipedia.org/wiki/Insulin_Resistance |
In normal mode the PFCs transmit actuator commands to the ACEs, which convert them into analog servo commands. Full functionality is provided, including all enhanced performance, envelope protection and ride quality features. | https://en.wikipedia.org/wiki/Flight_control_law |
In normal mode, the player has the ability to play 32 notes using the five fret buttons. The default notes assigned to the buttons are E1 to B3, although the player can modify these notes according to their preference. Normal mode employs a binary pattern for gameplay. | https://en.wikipedia.org/wiki/MIDItarHero |
In normal neuromuscular function, a nerve impulse is carried down the axon (the long projection of a nerve cell) from the spinal cord. At the nerve ending in the neuromuscular junction, where the impulse is transferred to the muscle cell, the nerve impulse leads to the opening of voltage-gated calcium channels (VGCC), the influx of calcium ions into the nerve terminal, and the calcium-dependent triggering of synaptic vesicle fusion with plasma membrane. These synaptic vesicles contain acetylcholine, which is released into the synaptic cleft and stimulates the acetylcholine receptors on the muscle. The muscle then contracts.In LEMS, antibodies against VGCC, particularly the P/Q-type VGCC, decrease the amount of calcium that can enter the nerve ending, hence less acetylcholine can be released from the neuromuscular junction. | https://en.wikipedia.org/wiki/Lambert–Eaton_myasthenic_syndrome |
Apart from skeletal muscle, the autonomic nervous system also requires acetylcholine neurotransmission; this explains the occurrence of autonomic symptoms in LEMS. P/Q voltage-gated calcium channels are also found in the cerebellum, explaining why some experience problems with coordination. | https://en.wikipedia.org/wiki/Lambert–Eaton_myasthenic_syndrome |
The antibodies bind particularly to the part of the receptor known as the "domain III S5–S6 linker peptide". Antibodies may also bind other VGCCs. Some have antibodies that bind synaptotagmin, the protein sensor for calcium-regulated vesicle fusion. | https://en.wikipedia.org/wiki/Lambert–Eaton_myasthenic_syndrome |
Many people with LEMS, both with and without VGCC antibodies, have detectable antibodies against the M1 subtype of the acetylcholine receptor; their presence may participate in a lack of compensation for the weak calcium influx.Apart from the decreased calcium influx, a disruption of active zone vesicle release sites also occurs, which may also be antibody-dependent, since people with LEMS have antibodies to components of these active zones (including voltage-dependent calcium channels). Together, these abnormalities lead to the decrease in muscle contractility. Repeated stimuli over a period of about 10 seconds eventually lead to sufficient delivery of calcium, and an increase in muscle contraction to normal levels, which can be demonstrated using an electrodiagnostic medicine study called needle electromyography by increasing amplitude of repeated compound muscle action potentials.The antibodies found in LEMS associated with lung cancer also bind to calcium channels in the cancer cells, and it is presumed that the antibodies originally develop as a reaction to these cells. It has been suggested that the immune reaction to the cancer cells suppresses their growth and improves the prognosis from the cancer. | https://en.wikipedia.org/wiki/Lambert–Eaton_myasthenic_syndrome |
In normal operation, a rolling-element bearing has the rollers and races separated by a thin layer of lubricant such as grease or oil. Although these lubricants normally appear liquid (not solid), under high pressure they act as solids and keep the bearing and race from touching.If the lubricant is removed, the bearings and races can touch directly. While bearings and races appear smooth to the eye, they are microscopically rough. Thus, high points of each surface can touch, but "valleys" do not. | https://en.wikipedia.org/wiki/False_brinelling |
The bearing load is thus spread over much less area increasing the contact stress, causing pieces of each surface to break off or to become pressure-welded then break off when the bearing rolls on. The broken-off pieces are also called wear debris. Wear debris is bad because it is relatively large compared to the surrounding surface finish and thus creates more regions of high contact stress. Worse, the steel in ordinary bearings can oxidize (rust), producing a more abrasive compound which accelerates wear. | https://en.wikipedia.org/wiki/False_brinelling |
In normal operation, the TCC uses access grid technology for video conferencing using the proprietary IOCOM software suite. The lectures take place in the virtual venue named Maths TCC. These lectures may be recorded upon request if permission from participants is obtained in advance. | https://en.wikipedia.org/wiki/Taught_Course_Centre |
TCC lectures normally transmit video streams using H.261 and audio as G.711 for compatibility with the freely available AG3 software. Each Access Grid session is paired with a Jabber/XMPP session on the Access Grid Support Centre (AGSC) Virtual Venue Server. The XMPP session allows instant messaging with other participants allowing fault diagnosis or communication without interrupting a session. | https://en.wikipedia.org/wiki/Taught_Course_Centre |
In normal operation, the spacecraft transmits a continuous 200 kbit/s data stream of photographs and other measurements via the NASA Deep Space Network of ground stations. SOHO's data about solar activity are used to predict coronal mass ejection (CME) arrival times at Earth, so electrical grids and satellites can be protected from their damaging effects. CMEs directed toward the earth may produce geomagnetic storms, which in turn produce geomagnetically induced currents, in the most extreme cases creating black-outs, etc. In 2003, ESA reported the failure of the antenna Y-axis stepper motor, necessary for pointing the high-gain antenna and allowing the downlink of high-rate data. At the time, it was thought that the antenna anomaly might cause two- to three-week data-blackouts every three months. However, ESA and NASA engineers managed to use SOHO's low-gain antennas together with the larger 34 m (112 ft) and 70 m (230 ft) NASA Deep Space Network ground stations and judicious use of SOHO's Solid State Recorder (SSR) to prevent total data loss, with only a slightly reduced data flow every three months. | https://en.wikipedia.org/wiki/SOHO_spacecraft |
In normal operations, the SHRIMP achieves mass resolution of 5000 with sensitivity >20 counts/sec/ppm/nA for lead from zircon. | https://en.wikipedia.org/wiki/Sensitive_high-resolution_ion_microprobe |
In normal physiology, glutamine plays a key role in signalling in enterocytes that are part of the intestinal barrier, but it is not clear if supplementing the diet with glutamine is helpful in conditions where there is increased intestinal permeability.Prebiotics and certain probiotics such as E.Coli strain Nissle 1917 have been found to reduce increased intestinal permeability. Lactobacillus rhamnosus, Lactobacillus reuteri, and Faecalibacterium prausnitzii have also been shown to significantly reduce increased intestinal permeability. Larazotide acetate (previously known as AT-1001) is a zonulin receptor antagonist that has been probed in clinical trials. | https://en.wikipedia.org/wiki/Bacterial_translocation |
It seems to be a drug candidate for use in conjunction with a gluten-free diet in people with celiac disease, with the aim to reduce the intestinal permeability caused by gluten and its passage through the epithelium, and therefore mitigating the resulting cascade of immune reactions.Decreasing intestinal barrier function with aging can cause increased translocation of microbial products, such as lipopolysaccharide, into the systemic blood circulation that subsequently causes systemic inflammation (inflammaging) and significant clinical outcomes: metabolic syndrome, decreased physical function, and mortality. It has been shown that the loss of intestinal barrier function is associated with an increased formation of nitric oxide (NO) and lower activity of arginase. Genetic disruption of arginase-2 in mouse attenuates the onset of senescence and extends lifespan. Arginase inhibitors have been developed to reduce the effect of NO on intestinal permeability. | https://en.wikipedia.org/wiki/Bacterial_translocation |
In normal pregnancy, the resident vaginal flora is thought to provide protection against infection. The microbiota during pregnancy are predominantly Lactobacillus species. Microbiota composition can change during the course of the pregnancy. If the microbiota populations become more diverse, indicating that the normal Lactobacillus-dominated population has changed to a bacterial vaginosis population, risks of adverse pregnancy outcomes increase. Vaginal discharge is common during pregnancy but is not an indicator of bacterial vaginosis or abnormal microbiota. The treatment of abnormal vaginal microbiota populations with lactobacilli and estriol during pregnancy was found to restore the microbiota to a normal state. | https://en.wikipedia.org/wiki/Vaginal_microbiota_in_pregnancy |
In normal respiratory function, the air flows in through the upper airway, down through the bronchi and into the lung parenchyma (the bronchioles down to the alveoli) where gas exchange of carbon dioxide and oxygen occurs. During inspiration, the lungs expand to allow airflow into the lungs and thereby increasing total volume. After inspiration follows expiration during which the lungs recoil and push air back out of the pulmonary pathway. Lung compliance is the difference of volume during inspiration and expiration.Restrictive lung disease is characterized by reduced lung volumes, and therefore reduced lung compliance, either due to an intrinsic reason, for example a change in the lung parenchyma, or due to an extrinsic reason, for example diseases of the chest wall, pleura, or respiratory muscles. | https://en.wikipedia.org/wiki/Restrictive_lung_disease |
Generally, intrinsic causes are from lung parenchyma diseases that cause inflammation or scarring of the lung tissue, such as interstitial lung disease or pulmonary fibrosis, or from having the alveoli air spaces filled with external material such as debris or exudate in pneumonitis. As some diseases of the lung parenchyma progress, the normal lung tissue can be gradually replaced with scar tissue that is interspersed with pockets of air. This can lead to parts of the lung having a honeycomb-like appearance. The extrinsic causes result in lung restriction, impaired ventilatory function, and even respiratory failure due to the diseases that effect the lungs ability to create a change in lung volumes during respiration due to the diseases of the systems stated above. | https://en.wikipedia.org/wiki/Restrictive_lung_disease |
In normal situations, lambs nurse after standing, receiving vital colostrum milk. Lambs that either fail to nurse or are prevented from doing so by the ewe require aid in order to live. If coaxing the pair to accept nursing does not work, one of several steps may then be taken. Ewes may be held or tied to force them to accept a nursing lamb. | https://en.wikipedia.org/wiki/Domestic_sheep_reproduction |
If a lamb is not eating, a stomach tube may also be used to force feed the lamb in order to save its life. In the case of a permanently rejected lamb, a shepherd may then attempt to foster an orphaned lamb onto another ewe. Lambs are also sometimes fostered after the death of their mother, either from the birth or other event. | https://en.wikipedia.org/wiki/Domestic_sheep_reproduction |
Scent plays a large factor in ewes recognizing their lambs, so disrupting the scent of a newborn lamb with washing or over-handling may cause a ewe to reject it. Conversely, various methods of imparting the scent of a ewe's own lamb to an orphaned one may be useful in fostering. If an orphaned lamb cannot be fostered, then it usually becomes what is known as a bottle lamb—a lamb raised by people and fed via bottle. | https://en.wikipedia.org/wiki/Domestic_sheep_reproduction |
After lambs are stabilized, lamb marking is carried out – this includes ear tagging, docking, castration and usually vaccination. Ear tags with numbers are the primary mode of identification when sheep are not named; it is also the legal manner of animal identification in the European Union: the number may identify the individual sheep or only its flock. When performed at an early age, ear tagging seems to cause little or no discomfort to lambs. | https://en.wikipedia.org/wiki/Domestic_sheep_reproduction |
However, using tags improperly or using tags not designed for sheep may cause discomfort, largely due to excess weight of tags for other animals.Ram lambs not intended for breeding are castrated, though some shepherds choose to avoid the procedure for ethical, economic or practical reasons. Ram lambs that will be slaughtered or separated from ewes before sexual maturity are not usually castrated. In most breeds, lambs' tails are docked for health reasons. | https://en.wikipedia.org/wiki/Domestic_sheep_reproduction |
The tail may be removed just below the lamb's caudal tail flaps (docking shorter than this may cause health problems such as rectal prolapse), but in some breeds the tail is left longer, or is not docked at all. Docking is not necessary in short-tailed breeds, and it is not usually done in breeds in which a long tail is valued, such as Zwartbles. Though docking is often considered cruel and unnatural by animal rights activists, it is considered by sheep producers large and small alike to be a critical step in maintaining the health of sheep. | https://en.wikipedia.org/wiki/Domestic_sheep_reproduction |
Long, wooly tails make shearing more difficult, interfere with mating, and make sheep extremely susceptible to parasites, especially those that cause flystrike. Both castration and docking can be performed with several instruments. | https://en.wikipedia.org/wiki/Domestic_sheep_reproduction |
An elastrator places a tight band of rubber around an area, causing it to atrophy and fall off in a number of weeks. This process is bloodless and does not seem to cause extended suffering to lambs, who tend to ignore it after several hours. In addition to the elastrator, a Burdizzo, emasculator, heated chisel or knife are sometimes used. After one to three days in the lambing jugs, ewes and lambs are usually sufficiently stabilized to allow reintroduction to the rest of the flock. | https://en.wikipedia.org/wiki/Domestic_sheep_reproduction |
In normal stem and progenitor cells, asymmetric cell division balances proliferation and self-renewal with cell-cycle exit and differentiation. Disruption of asymmetric cell division leads to aberrant self-renewal and impairs differentiation, and could therefore constitute an early step in the tumorogenic transformation of stem and progenitor cells. In normal non-tumor stem cells, a number of genes have been described which are responsible for pluripotency, such as Bmi-1, Wnt and Notch. These genes have been discovered also in the case of cancer stem cells, and shows that their aberrant expression is essential for the formation of tumor cell mass. | https://en.wikipedia.org/wiki/Asymmetric_cell_division |
For example, it has been shown that gastrointestinal cancers contain rare subpopulation of cancer stem cells which are capable to divide asymmetrically. The asymmetric division in these cells is regulated by cancer niche (microenvironment) and Wnt pathway. | https://en.wikipedia.org/wiki/Asymmetric_cell_division |
Blocking the Wnt pathway with IWP2 (WNT antagonist) or siRNA-TCF4 resulted in high suppression of asymmetric cell division.Another mutation in asymmetric cell divisions which are involved in tumor growth are loss-of-function mutations. The first suggestion that loss of asymmetric cell division might be involved in tumorigenesis came from studies of Drosophila. Studies of loss-of-function mutations in key regulators of asymmetric cell division including lgl, aurA, polo, numb and brat, revealed hyperproliferative phenotypes in situ. In these mutants cells divide more symmetrically and generate mis-specified progeny that fail to exit the cell cycle and differentiate, but rather proliferate continuously and form a tumor cell mass. | https://en.wikipedia.org/wiki/Asymmetric_cell_division |
In normal subjects, the left ventricular ejection fraction (LVEF) should be about 50%(range, 50-80%). There should be no area of abnormal wall motion (hypokinesis, akinesis or dyskinesis). Abnormalities in cardiac function may be manifested as a decrease in LVEF and/or the presence of abnormalities in global and regional wall motion. For normal subjects, peak filling rates should be between 2.4 and 3.6 end diastolic volume (EDV) per second, and the time to peak filling rate should be 135-212 ms. | https://en.wikipedia.org/wiki/Radionuclide_ventriculography |
In normal tissue, STAT5a mediates effects of prolactin in mammary glands. In breast cancer, STAT5a signaling is important for maintain tumor differentiation and suppressing disease progression. Studies originally showed a correlation between high STAT5a expression and tumor differentiation in mice models, but histopathological analysis of human breast cancer tissue has shown a different trend. | https://en.wikipedia.org/wiki/STAT5A |
It was shown that low nuclear levels of STAT5a was associated with unfavorable clinical outcomes and cancer progression independent of STAT5b expression. High STAT5a was suggested to be an inhibitor of invasion and metastasis and therefore an indicator of favorable clinical outcomes. Because of these trends, it has been proposed as a predictor of response to therapies such as anti-estrogen treatment. | https://en.wikipedia.org/wiki/STAT5A |
In normal tissues, CT antigens are exclusively expressed in testis, making it no access to the immune system. Besides, the existence of blood-testis barrier and the lack of human leukocyte antigen (HLA) class I expression on the surface of germ cells prevent the immune system interacting with CT antigens proteins and recognizing it as invading structures. Thus, CT antigens can be regarded as essentially tumor-specific targets when they are expressed in cancers. Distinct CT antigens encode for different antigenic peptides presented to the immune system in association with various HLA class I or HLA class II allospecificities, eliciting both CTL and humoral immune responses. | https://en.wikipedia.org/wiki/Cancer/testis_antigens |
In normal usage, the rate-limiting step or rate-determining step is defined as the slowest step of a chemical reaction that determines the speed (rate) at which the overall reaction proceeds. The flux control coefficients do not measure this kind of rate-limitingness. For example, in a linear chain of reactions at steady-state, all steps carry the same flux. That is, there is no slow or fast step with respect to the rate or speed of a reaction. | https://en.wikipedia.org/wiki/Control_coefficient_(biochemistry) |
The flux control coefficient, instead, measures how much influence a given step has on the steady-state flux. A step with a high flux control coefficient means that changing the activity of the step (by changing the expression level of the enzyme) will have a large effect on the steady-state flux through the pathway and vice versa. Historically the concept of the rate-limiting steps was also related to the notion of the master step. However, this drew much criticism due to a misunderstanding of the concept of the steady-state. | https://en.wikipedia.org/wiki/Control_coefficient_(biochemistry) |
In normal use it is often desirable to have a way to arbitrarily query the data within a particular Topic Maps store. Many implementations provide a syntax by which this can be achieved (somewhat like 'SQL for Topic Maps') but the syntax tends to vary a lot between different implementations. With this in mind, work has gone into defining a standardized syntax for querying topic maps: ISO 18048: TMQL – Topic Maps Query Language | https://en.wikipedia.org/wiki/Topic_Maps |
In normal use, a modem can send or receive data at any point in time, a mode of operation known as "asynchronous". The modem can determine the speed of the sender's data by listening to the bits being sent to it, and "locking" its clock to the speed of bits being received. Since the data can arrive at any time, there is no precise timing; the clock may have to be re-adjusted for pauses as the user stops typing (for instance). Unfortunately, this sort of clock decoding does not work unless there are at least some transitions between 1 and 0 in the data; a long stream of 0s or 1s has no transitions in it, making it impossible to know where the data for any particular byte starts. | https://en.wikipedia.org/wiki/Microcom_Networking_Protocol |
In order to avoid this problem, additional framing bits are added to either end of every byte, typically one bit on either side known as the "start and stop bits". This guarantees at least one 1-to-0 transition for every byte, more than enough to keep the clocks locked. However, these bits also expand every 8 bits of data (one byte) to 10 bits, an overhead of 20%. | https://en.wikipedia.org/wiki/Microcom_Networking_Protocol |
When using a file transfer protocol, the packets themselves offer their own framing. The packets will always send a continuous stream of data, so the clock cannot "drift" in the same way that it could for data being sent by a user typing on a keyboard. By turning off these framing bits when operating on an error-corrected link, that 20% overhead can be eliminated. | https://en.wikipedia.org/wiki/Microcom_Networking_Protocol |
This is precisely what MNP 3 did. After negotiating and determining that both modems supported MNP 3, the framing bits were turned off, improving overall efficiency by about 20%. This almost perfectly offset the overhead of the protocol, meaning that when using MNP 3, a user can expect to get very close to the ideal 2400 bit/s throughput (versus 1900 bit/s). | https://en.wikipedia.org/wiki/Microcom_Networking_Protocol |
In normal use, a nut-and-bolt joint holds together because the bolt is under a constant tensile stress called the preload. The preload pulls the nut threads against the bolt threads, and the nut face against the bearing surface, with a constant force, so that the nut cannot rotate without overcoming the friction between these surfaces. If the joint is subjected to vibration, however, the preload increases and decreases with each cycle of movement. If the minimum preload during the vibration cycle is not enough to hold the nut firmly in contact with the bolt and the bearing surface, then the nut is likely to become loose. | https://en.wikipedia.org/wiki/Jam_nut |
Specialized locking nuts exist to prevent this problem, but sometimes it is sufficient to add a second nut. For this technique to be reliable, each nut must be tightened to the correct torque. The inner nut is tightened to about a quarter to a half of the torque of the outer nut. | https://en.wikipedia.org/wiki/Jam_nut |
It is then held in place by a wrench while the outer nut is tightened on top using the full torque. This arrangement causes the two nuts to push against each other, creating a tensile stress in the short section of the bolt that lies between them. Even when the main joint is vibrated, the stress between the two nuts remains constant, thus holding the nut threads in constant contact with the bolt threads and preventing self-loosening. | https://en.wikipedia.org/wiki/Jam_nut |
When the joint is assembled correctly, the outer nut bears the full tension of the joint. The inner nut functions merely to add a small additional force to the outer nut and does not need to be as strong, so a thin nut can be used.The jam nut essentially acts as the "other object", as the two nuts are tightened against each other. They can also be used to secure an item on a fastener without applying force to that object. | https://en.wikipedia.org/wiki/Jam_nut |
This is achieved by first tightening one of the nuts onto the item. Then the other nut is screwed down on top of the first nut. | https://en.wikipedia.org/wiki/Jam_nut |
The inner nut is then slackened back and tightened against the outer nut. Jam nuts can also be used in situations where a threaded rod must be rotated. Since threaded rods have no bolt heads, it is difficult or impossible to apply torque to a threaded rod. | https://en.wikipedia.org/wiki/Jam_nut |
A pair of jam nuts is used to create a point where a wrench may be used. Jam nuts can be unreliable under significant loads. If the inner nut is torqued more than the outer nut, the outer nut may yield. If the outer nut is torqued more than the inner nut, the inner nut may loosen up. == References == | https://en.wikipedia.org/wiki/Jam_nut |
In normal use, electrical equipment often creates tiny electric arcs (internal sparks) in switches, motor brushes, connectors, and in other places. Compact electrical equipment generates heat as well, which under some circumstances can become an ignition source. There are multiple ways to make equipment safe for use in explosive-hazardous areas. | https://en.wikipedia.org/wiki/Intrinsic_safety |
Intrinsic safety (denoted by "i" in the ATEX and IECEx Explosion Classifications) is one of several available methods for electrical equipment. see Types of protection for more info. For handheld electronics, intrinsic safety is the only realistic method that allows a functional device to be explosion protected. | https://en.wikipedia.org/wiki/Intrinsic_safety |
A device which is termed "intrinsically safe" has been designed to be incapable of producing heat or spark sufficient to ignite an explosive atmosphere, even if the device has experienced deterioration or has been damaged. There are several considerations in designing intrinsically safe electronics devices: reducing or eliminating internal sparking. controlling component temperatures. | https://en.wikipedia.org/wiki/Intrinsic_safety |
eliminating component spacing that would allow dust to short a circuit.Elimination of spark potential within components is accomplished by limiting the available energy in any given circuit and the system as a whole. Temperature, under certain fault conditions such as an internal short in a semiconductor device, becomes an issue as the temperature of a component can rise to a level that can ignite some explosive gasses, even in normal use. Safeguards, such as current limiting by resistors and fuses, must be employed to ensure that in no circumstance can a component reach a temperature that could cause autoignition of a combustible atmosphere. | https://en.wikipedia.org/wiki/Intrinsic_safety |
In the highly compact electronic devices used today PCBs often have component spacing that create the possibility of an arc between components if dust or other particulate matter works into the circuitry, thus component spacing, siting and isolation become important to the design. The primary concept behind intrinsic safety is the restriction of available electrical and thermal energy in the system so that ignition of a hazardous atmosphere (explosive gas or dust) cannot occur. This is achieved by ensuring that only low voltages and currents enter the hazardous area, and that no significant energy storage is possible. | https://en.wikipedia.org/wiki/Intrinsic_safety |
One of the most common methods for protection is to limit electric current by using series resistors (using types of resistors that always fail open); and limit the voltage with multiple zener diodes. In zener barriers dangerous incoming potentials are grounded, with galvanic isolation barriers there is no direct connection between the safe- and hazardous-area circuits by interposing a layer of insulation between the two. Certification standards for intrinsic safety designs (mainly IEC 60079-11 but since 2015 also IEC TS 60079-39) generally require that the barrier do not exceed approved levels of voltage and current with specified damage to limiting components. | https://en.wikipedia.org/wiki/Intrinsic_safety |
Equipment or instrumentation for use in a hazardous area will be designed to operate with low voltage and current, and will be designed without any large capacitors or inductors that could discharge in a spark. The instrument will be connected, using approved wiring methods, back to a control panel in a non-hazardous area that contains safety barriers. The safety barriers ensure that, in normal operation, and with the application of faults according to the Equipment Protection Level, EPL, also if accidental contact occurs between the instrument circuit and other power sources, no more than the approved voltage and current enters the hazardous area. | https://en.wikipedia.org/wiki/Intrinsic_safety |
For example, during marine transfer operations when flammable products are transferred between the marine terminal and tanker ships or barges, two-way radio communication needs to be constantly maintained in case the transfer needs to stop for unforeseen reasons such as a spill. The United States Coast Guard requires that the two way radio must be certified as intrinsically safe. Another example is intrinsically safe or explosion-proof mobile phones used in explosive atmospheres, such as refineries. | https://en.wikipedia.org/wiki/Intrinsic_safety |
Intrinsically safe mobile phones must meet special battery design criteria in order to achieve UL, ATEX directive, or IECEx certification for use in explosive atmospheres. Only properly designed battery-operated, self-contained devices can be intrinsically safe by themselves. Other field devices and wiring are intrinsically safe only when employed in a properly designed IS system. Such systems shall be designed and documented according to the standard: IEC 60079-25 Intrinsically safe electrical systems, IEC 60079-14 Electrical installations design, selection and erection IEC 60079-17 Electrical installations inspection and maintenance | https://en.wikipedia.org/wiki/Intrinsic_safety |
In normal vision, diffraction through eyelashes – and due to the edges of the eyelids if one is squinting – produce many diffraction spikes. If it is windy, then the motion of the eyelashes cause spikes that move around and scintillate. After a blink, the eyelashes may come back in a different position and cause the diffraction spikes to jump around. This is classified as an entoptic phenomenon. | https://en.wikipedia.org/wiki/Diffraction_spike |
In normal-phase chromatography, the stationary phase is polar and the mobile phase is nonpolar. In reversed phase the opposite is true; the stationary phase is nonpolar and the mobile phase is polar. Typical stationary phases for normal-phase chromatography are silica or organic moieties with cyano and amino functional groups. For reversed phase, alkyl hydrocarbons are the preferred stationary phase; octadecyl (C18) is the most common stationary phase, but octyl (C8) and butyl (C4) are also used in some applications. | https://en.wikipedia.org/wiki/Aqueous_normal-phase_chromatography |
The designations for the reversed phase materials refer to the length of the hydrocarbon chain. In normal-phase chromatography, the least polar compounds elute first and the most polar compounds elute last. The mobile phase consists of a nonpolar solvent such as hexane or heptane mixed with a slightly more polar solvent such as isopropanol, ethyl acetate or chloroform. | https://en.wikipedia.org/wiki/Aqueous_normal-phase_chromatography |
Retention decreases as the amount of polar solvent in the mobile phase increases. In reversed phase chromatography, the most polar compounds elute first with the most nonpolar compounds eluting last. The mobile phase is generally a binary mixture of water and a miscible polar organic solvent like methanol, acetonitrile or THF. | https://en.wikipedia.org/wiki/Aqueous_normal-phase_chromatography |
Retention increases as the amount of the polar solvent (water) in the mobile phase increases. Normal phase chromatography, an adsorptive mechanism, is used for the analysis of solutes readily soluble in organic solvents, based on their polar differences such as amines, acids, metal complexes, etc.. Reversed-phase chromatography, a partition mechanism, is typically used for separations by non-polar differences. The "hydride surface" distinguishes the support material from other silica materials; most silica materials used for chromatography have a surface composed primarily of silanols (-Si-OH). | https://en.wikipedia.org/wiki/Aqueous_normal-phase_chromatography |
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