Indole is an organic compound with the formula C 6 H 4 CCNH 3 . Indole is classified as an aromatic heterocycle . It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indoles are derivatives of indole where one or more of the hydrogen atoms have been replaced by substituent groups. Indoles are widely distributed in nature, most notably as amino acid tryptophan and neurotransmitter serotonin .
128-626: Indole is a solid at room temperature. It occurs naturally in human feces and has an intense fecal odor . At very low concentrations, however, it has a flowery smell, and is a constituent of many perfumes . It also occurs in coal tar . It has been identified in cannabis . It is the main volatile compound in stinky tofu . When indole is a substituent on a larger molecule, it is called an indolyl group by systematic nomenclature . Indole undergoes electrophilic substitution , mainly at position 3 (see diagram in right margin). Substituted indoles are structural elements of (and for some compounds,
256-432: A healthy diet . If lifestyle changes are not sufficient, blood pressure medications are used. Up to three medications taken concurrently can control blood pressure in 90% of people. The treatment of moderately high arterial blood pressure (defined as >160/100 mmHg) with medications is associated with an improved life expectancy . The effect of treatment of blood pressure between 130/80 mmHg and 160/100 mmHg
384-515: A rock sample is a random aggregate of minerals and/or mineraloids , and has no specific chemical composition. The vast majority of the rocks of the Earth's crust consist of quartz (crystalline SiO 2 ), feldspar, mica, chlorite , kaolin , calcite, epidote , olivine , augite , hornblende , magnetite , hematite , limonite and a few other minerals. Some minerals, like quartz , mica or feldspar are common, while others have been found in only
512-412: A western diet and lifestyle, and the risk of becoming hypertensive in later life is substantial in most such societies. Several environmental or lifestyle factors influence blood pressure. Reducing dietary salt intake lowers blood pressure; as does weight loss, exercise training, vegetarian diets, increased dietary potassium intake and high dietary calcium supplementation. Increasing alcohol intake
640-469: A clearly identifiable cause, such as chronic kidney disease , narrowing of the kidney arteries , an endocrine disorder , or the use of birth control pills . Blood pressure is classified by two measurements, the systolic (first number) and diastolic (second number) pressures. For most adults, normal blood pressure at rest is within the range of 100–140 millimeters mercury (mmHg) systolic and 60–90 mmHg diastolic. For most adults, high blood pressure
768-525: A coin, are chemically identical throughout, many other common materials comprise a number of different substances packed together. For example, a typical rock is an aggregate of several different minerals and mineraloids , with no specific chemical composition. Wood is a natural organic material consisting primarily of cellulose fibers embedded in a matrix of organic lignin . In materials science, composites of more than one constituent material can be designed to have desired properties. The forces between
896-511: A complex interaction of genes and environmental factors. More than 2000 common genetic variants with small effects on blood pressure have been identified in association with high blood pressure, as well as some rare genetic variants with large effects on blood pressure. There is also evidence that DNA methylation at multiple nearby CpG sites may link some sequence variation to blood pressure, possibly via effects on vascular or renal function. Blood pressure rises with aging in societies with
1024-541: A composite made up of a thermoplastic matrix such as acrylonitrile butadiene styrene (ABS) in which calcium carbonate chalk, talc , glass fibers or carbon fibers have been added for strength, bulk, or electro-static dispersion. These additions may be referred to as reinforcing fibers, or dispersants, depending on their purpose. Thus, the matrix material surrounds and supports the reinforcement materials by maintaining their relative positions. The reinforcements impart their special mechanical and physical properties to enhance
1152-928: A decrease in SBP by 5-15mmHg, versus resistance training showing a decrease of only 3-5mmHg. Aerobic exercises such as jogging, rowing, dancing, or hiking can decrease SBP the greatest. The decrease in SBP can regulate the effect of hypertension ensuring the baby will not be harmed. Resistance training takes a toll on the cardiovascular system in untrained individuals, leading to a reluctance in prescription of resistance training for hypertensive reduction purposes. Failure to thrive , seizures , irritability , lack of energy , and difficulty in breathing can be associated with hypertension in newborns and young infants. In older infants and children, hypertension can cause headache, unexplained irritability, fatigue , failure to thrive, blurred vision , nosebleeds , and facial paralysis . Primary (also termed essential) hypertension results from
1280-438: A decreased blood pressure in the lower extremities relative to the arms, or delayed or absent femoral arterial pulses . Pheochromocytoma may cause abrupt episodes of hypertension accompanied by headache, palpitations , pale appearance , and excessive sweating . Severely elevated blood pressure (equal to or greater than a systolic 180 mmHg or diastolic of 120 mmHg) is referred to as a hypertensive crisis. Hypertensive crisis
1408-1043: A few locations worldwide. The largest group of minerals by far is the silicates (most rocks are ≥95% silicates), which are composed largely of silicon and oxygen , with the addition of ions of aluminium, magnesium , iron, calcium and other metals. Ceramic solids are composed of inorganic compounds, usually oxides of chemical elements. They are chemically inert, and often are capable of withstanding chemical erosion that occurs in an acidic or caustic environment. Ceramics generally can withstand high temperatures ranging from 1,000 to 1,600 °C (1,830 to 2,910 °F). Exceptions include non-oxide inorganic materials, such as nitrides , borides and carbides . Traditional ceramic raw materials include clay minerals such as kaolinite , more recent materials include aluminium oxide ( alumina ). The modern ceramic materials, which are classified as advanced ceramics, include silicon carbide and tungsten carbide . Both are valued for their abrasion resistance, and hence find use in such applications as
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#17327658035911536-561: A flat surface at the level of the heart. Blood pressure measurement should be done in a quiet room so the medical professional checking the blood pressure can hear the Korotkoff sounds while listening to the brachial artery with a stethoscope for accurate blood pressure measurements. The blood pressure cuff should be deflated slowly (2–3 mmHg per second) while listening for the Korotkoff sounds. The bladder should be emptied before
1664-511: A force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. The atoms in a solid are bound to each other, either in a regular geometric lattice ( crystalline solids , which include metals and ordinary ice ), or irregularly (an amorphous solid such as common window glass). Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because
1792-437: A formula for indole. Certain indole derivatives were important dyestuffs until the end of the 19th century. In the 1930s, interest in indole intensified when it became known that the indole substituent is present in many important alkaloids , known as indole alkaloids (e.g., tryptophan and auxins ), and it remains an active area of research today. Indole is biosynthesized in the shikimate pathway via anthranilate . It
1920-416: A hump of fat behind the neck and shoulders (referred to as a buffalo hump), and purple abdominal stretch marks . Hyperthyroidism frequently causes weight loss with increased appetite, fast heart rate , bulging eyes , and tremor. Renal artery stenosis may be associated with a localized abdominal bruit to the left or right of the midline, or in both locations. Coarctation of the aorta frequently causes
2048-580: A material can absorb before mechanical failure, while fracture toughness (denoted K Ic ) describes the ability of a material with inherent microstructural flaws to resist fracture via crack growth and propagation. If a material has a large value of fracture toughness , the basic principles of fracture mechanics suggest that it will most likely undergo ductile fracture. Brittle fracture is very characteristic of most ceramic and glass-ceramic materials that typically exhibit low (and inconsistent) values of K Ic . For an example of applications of ceramics,
2176-558: A material that indicates its ability to conduct heat . Solids also have a specific heat capacity , which is the capacity of a material to store energy in the form of heat (or thermal lattice vibrations). Electrical properties include both electrical resistivity and conductivity , dielectric strength , electromagnetic permeability , and permittivity . Electrical conductors such as metals and alloys are contrasted with electrical insulators such as glasses and ceramics. Semiconductors behave somewhere in between. Whereas conductivity in metals
2304-440: A meltdown of the metallic parts. Work is also being done in developing ceramic parts for gas turbine engines . Turbine engines made with ceramics could operate more efficiently, giving aircraft greater range and payload for a set amount of fuel. Such engines are not in production, however, because the manufacturing of ceramic parts in the sufficient precision and durability is difficult and costly. Processing methods often result in
2432-578: A metallic conductor, current is carried by the flow of electrons, but in semiconductors, current can be carried either by electrons or by the positively charged " holes " in the electronic band structure of the material. Common semiconductor materials include silicon, germanium and gallium arsenide . Many traditional solids exhibit different properties when they shrink to nanometer sizes. For example, nanoparticles of usually yellow gold and gray silicon are red in color; gold nanoparticles melt at much lower temperatures (~300 °C for 2.5 nm size) than
2560-422: A non-crystalline intergranular phase. Glass-ceramics are used to make cookware (originally known by the brand name CorningWare ) and stovetops that have high resistance to thermal shock and extremely low permeability to liquids. The negative coefficient of thermal expansion of the crystalline ceramic phase can be balanced with the positive coefficient of the glassy phase. At a certain point (~70% crystalline)
2688-529: A periodic lattice. Mathematically, the potential of the ion cores can be treated by various models, the simplest being the nearly free electron model . Minerals are naturally occurring solids formed through various geological processes under high pressures. To be classified as a true mineral, a substance must have a crystal structure with uniform physical properties throughout. Minerals range in composition from pure elements and simple salts to very complex silicates with thousands of known forms. In contrast,
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#17327658035912816-414: A person's blood pressure is measured since this can increase blood pressure by up to 15/10 mmHg. Multiple blood pressure readings (at least two) spaced 1–2 minutes apart should be obtained to ensure accuracy. Ambulatory blood pressure monitoring over 12 to 24 hours is the most accurate method to confirm the diagnosis. An exception to this is those with very high blood pressure readings especially when there
2944-405: A piezoelectric response several times larger than the traditional piezoelectric material quartz (crystalline SiO 2 ). The deformation (~0.1%) lends itself to useful technical applications such as high-voltage sources, loudspeakers, lasers, as well as chemical, biological, and acousto-optic sensors and/or transducers. Hypertension Hypertension , also known as high blood pressure ,
3072-439: A prior minor disturbance such as a silent heart attack. Blood pressure measurements can be influenced by circumstances of measurement. Guidelines use different thresholds for office (also known as clinic), home (when the patient measures their own blood pressure at home), and ambulatory blood pressure (using an automated device over a 24-hour period). Hypertension occurs in around 0.2 to 3% of newborns; however, blood pressure
3200-499: A resin during processing, which is then shaped into a final form. Polymers that have been around, and that are in current widespread use, include carbon-based polyethylene , polypropylene , polyvinyl chloride , polystyrene , nylons, polyesters , acrylics , polyurethane , and polycarbonates , and silicon-based silicones . Plastics are generally classified as "commodity", "specialty" and "engineering" plastics. Composite materials contain two or more macroscopic phases, one of which
3328-442: A significant portion of the fields of solid-state chemistry, physics, materials science and engineering. Metallic solids are held together by a high density of shared, delocalized electrons, known as " metallic bonding ". In a metal, atoms readily lose their outermost ("valence") electrons , forming positive ions . The free electrons are spread over the entire solid, which is held together firmly by electrostatic interactions between
3456-454: A single crystal, but instead are made of a large number of single crystals, known as crystallites , whose size can vary from a few nanometers to several meters. Such materials are called polycrystalline . Almost all common metals, and many ceramics , are polycrystalline. In other materials, there is no long-range order in the position of the atoms. These solids are known as amorphous solids ; examples include polystyrene and glass. Whether
3584-435: A solid is crystalline or amorphous depends on the material involved, and the conditions in which it was formed. Solids that are formed by slow cooling will tend to be crystalline, while solids that are frozen rapidly are more likely to be amorphous. Likewise, the specific crystal structure adopted by a crystalline solid depends on the material involved and on how it was formed. While many common objects, such as an ice cube or
3712-432: A variety of methods. The main industrial routes start from aniline via vapor-phase reaction with ethylene glycol in the presence of catalysts : In general, reactions are conducted between 200 and 500 °C. Yields can be as high as 60%. Other precursors to indole include formyltoluidine , 2-ethylaniline, and 2-(2-nitrophenyl)ethanol, all of which undergo cyclizations . The Leimgruber–Batcho indole synthesis
3840-692: A way that the strain is directly proportional to the stress ( Hooke's law ). The coefficient of the proportion is called the modulus of elasticity or Young's modulus . This region of deformation is known as the linearly elastic region. Three models can describe how a solid responds to an applied stress: Many materials become weaker at high temperatures. Materials that retain their strength at high temperatures, called refractory materials , are useful for many purposes. For example, glass-ceramics have become extremely useful for countertop cooking, as they exhibit excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C. In
3968-471: A wide distribution of microscopic flaws that frequently play a detrimental role in the sintering process, resulting in the proliferation of cracks, and ultimate mechanical failure. Glass-ceramic materials share many properties with both non-crystalline glasses and crystalline ceramics . They are formed as a glass, and then partially crystallized by heat treatment, producing both amorphous and crystalline phases so that crystalline grains are embedded within
Indole - Misplaced Pages Continue
4096-414: A wide variety of polymers and plastics . Wood is a natural organic material consisting primarily of cellulose fibers embedded in a matrix of lignin . Regarding mechanical properties, the fibers are strong in tension, and the lignin matrix resists compression. Thus wood has been an important construction material since humans began building shelters and using boats. Wood to be used for construction work
4224-511: Is C3, which is 10 times more reactive than benzene . For example, it is alkylated by phosphorylated serine in the biosynthesis of the amino acid tryptophan. Vilsmeier–Haack formylation of indole will take place at room temperature exclusively at C3. Since the pyrrolic ring is the most reactive portion of indole, electrophilic substitution of the carbocyclic (benzene) ring generally takes place only after N1, C2, and C3 are substituted. A noteworthy exception occurs when electrophilic substitution
4352-435: Is a hypertensive emergency and has several serious complications including vision loss , brain swelling , seizures , kidney failure , pulmonary edema , and disseminated intravascular coagulation (a blood clotting disorder). In contrast, gestational hypertension is defined as new-onset hypertension during pregnancy without protein in the urine. There have been significant findings on how exercising can help reduce
4480-464: Is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major risk factor for stroke , coronary artery disease , heart failure , atrial fibrillation , peripheral arterial disease , vision loss , chronic kidney disease , and dementia . Hypertension is a major cause of premature death worldwide. High blood pressure
4608-507: Is a component of syndrome X (or metabolic syndrome ), can cause hyperuricemia and gout and is also associated with elevated blood pressure. Events in early life, such as low birth weight , maternal smoking , and lack of breastfeeding may be risk factors for adult essential hypertension, although strength of the relationships is weak and the mechanisms linking these exposures to adult hypertension remain unclear. Secondary hypertension results from an identifiable cause. Kidney disease
4736-519: Is a form of salt -sensitive hypertension, where sodium intake does not modulate either adrenal or renal vascular responses to angiotensin II . They make up 25% of the hypertensive population. Hypertension is diagnosed on the basis of a persistently high resting blood pressure. Elevated blood pressure measurements on at least two separate occasions is required for a diagnosis of hypertension. For an accurate diagnosis of hypertension to be made, it
4864-493: Is abnormally high, but diastolic pressure may be normal or low, a condition termed isolated systolic hypertension . The high pulse pressure in elderly people with hypertension or isolated systolic hypertension is explained by increased arterial stiffness , which typically accompanies aging and may be exacerbated by high blood pressure. Many mechanisms have been proposed to account for the rise in peripheral resistance in hypertension. Most evidence implicates either disturbances in
4992-686: Is also a fundamental feature of many biological materials and the manner by which the structures are assembled from the molecular level up. Thus, self-assembly is emerging as a new strategy in the chemical synthesis of high performance biomaterials. Physical properties of elements and compounds that provide conclusive evidence of chemical composition include odor, color, volume, density (mass per unit volume), melting point, boiling point, heat capacity, physical form and shape at room temperature (solid, liquid or gas; cubic, trigonal crystals, etc.), hardness, porosity, index of refraction and many others. This section discusses some physical properties of materials in
5120-473: Is also associated with decreased peripheral venous compliance , which may increase venous return , increase cardiac preload and, ultimately, cause diastolic dysfunction . For patients having hypertension, higher heart rate variability (HRV) is a risk factor for atrial fibrillation . Pulse pressure (the difference between systolic and diastolic blood pressure) is frequently increased in older people with hypertension. This can mean that systolic pressure
5248-413: Is an efficient method of synthesizing indole and substituted indoles. Originally disclosed in a patent in 1976, this method is high-yielding and can generate substituted indoles. This method is especially popular in the pharmaceutical industry , where many pharmaceutical drugs are made up of specifically substituted indoles. One of the oldest and most reliable methods for synthesizing substituted indoles
Indole - Misplaced Pages Continue
5376-658: Is an intermediate in the biosynthesis of tryptophan , where it stays inside the tryptophan synthase molecule between the removal of 3-phospho-glyceraldehyde and the condensation with serine . When indole is needed in the cell, it is usually produced from tryptophan by tryptophanase . As an intercellular signal molecule , indole regulates various aspects of bacterial physiology, including spore formation, plasmid stability, resistance to drugs , biofilm formation, and virulence . A number of indole derivatives have important cellular functions, including neurotransmitters such as serotonin . Common classical methods applied for
5504-403: Is associated with elevated blood pressure. Air pollution is associated with hypertension. Whether these associations are causal is unknown. Gout and elevated blood uric acid are associated with hypertension and evidence from genetic ( Mendelian Randomization) studies and clinical trials indicate this relationship is likely to be causal. Insulin resistance , which is common in obesity and
5632-424: Is associated with higher blood pressure, but the possible roles of other factors such as caffeine consumption, and vitamin D deficiency are less clear. Average blood pressure is higher in the winter than in the summer. Depression is associated with hypertension and loneliness is also a risk factor. Periodontal disease is also associated with high blood pressure. Arsenic exposure through drinking water
5760-419: Is being measured to sit quietly for at least five minutes which is then followed by application of a properly fitted blood pressure cuff to a bare upper arm. The person should be seated with their back supported, feet flat on the floor, and with their legs uncrossed. The person whose blood pressure is being measured should avoid talking or moving during this process. The arm being measured should be supported on
5888-690: Is carried out in conditions sufficiently acidic to exhaustively protonate C3. In this case, C5 is the most common site of electrophilic attack. Gramine , a useful synthetic intermediate, is produced via a Mannich reaction of indole with dimethylamine and formaldehyde . It is the precursor to indole-3-acetic acid and synthetic tryptophan. The N–H center has a p K a of 21 in DMSO , so that very strong bases such as sodium hydride or n -butyl lithium and water-free conditions are required for complete deprotonation . The resulting organometalic derivatives can react in two ways. The more ionic salts such as
6016-522: Is categorized as either hypertensive urgency or hypertensive emergency , according to the absence or presence of end organ damage, respectively. In hypertensive urgency, there is no evidence of end organ damage resulting from the elevated blood pressure. In these cases, oral medications are used to lower the BP gradually over 24 to 48 hours. In hypertensive emergency, there is evidence of direct damage to one or more organs. The most affected organs include
6144-469: Is caused by electrons, both electrons and holes contribute to current in semiconductors. Alternatively, ions support electric current in ionic conductors . Many materials also exhibit superconductivity at low temperatures; they include metallic elements such as tin and aluminium, various metallic alloys, some heavily doped semiconductors, and certain ceramics. The electrical resistivity of most electrical (metallic) conductors generally decreases gradually as
6272-462: Is classified as primary (essential) hypertension or secondary hypertension . About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors. Lifestyle factors that increase the risk include excess salt in the diet, excess body weight , smoking , physical inactivity and alcohol use. The remaining 5–10% of cases are categorized as secondary hypertension, defined as high blood pressure due to
6400-416: Is commonly known as lumber or timber . In construction, wood is not only a structural material, but is also used to form the mould for concrete. Wood-based materials are also extensively used for packaging (e.g. cardboard) and paper, which are both created from the refined pulp. The chemical pulping processes use a combination of high temperature and alkaline (kraft) or acidic (sulfite) chemicals to break
6528-446: Is considerable evidence that reducing dietary salt intake lowers blood pressure , but whether this translates into a reduction in mortality and cardiovascular disease remains uncertain. Estimated sodium intake ≥6 g/day and <3 g/day are both associated with high risk of death or major cardiovascular disease, but the association between high sodium intake and adverse outcomes is only observed in people with hypertension. Consequently, in
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#17327658035916656-435: Is defined as an average systolic or diastolic blood pressure on three or more occasions equal or higher than the 95th percentile appropriate for the sex, age and height of the child. High blood pressure must be confirmed on repeated visits however before characterizing a child as having hypertension. In adolescents, it has been proposed that hypertension is diagnosed and classified using the same criteria as in adults. Much of
6784-399: Is essential for proper blood pressure measurement technique to be used. Improper measurement of blood pressure is common and can change the blood pressure reading by up to 10 mmHg, which can lead to misdiagnosis and misclassification of hypertension. Correct blood pressure measurement technique involves several steps. Proper blood pressure measurement requires the person whose blood pressure
6912-479: Is less clear, with some reviews finding benefit and others finding unclear benefit. High blood pressure affects 33% of the population globally. About half of all people with high blood pressure do not know that they have it. In 2019, high blood pressure was believed to have been a factor in 19% of all deaths (10.4 million globally). Hypertension is rarely accompanied by symptoms . Half of all people with hypertension are unaware that they have it. Hypertension
7040-434: Is lifestyle changes, including dietary changes, physical activity, and weight loss. Though these have all been recommended in scientific advisories, a Cochrane systematic review found no evidence (due to lack of data) for effects of weight loss diets on death, long-term complications or adverse events in persons with hypertension. The review did find a decrease in body weight and blood pressure. Their potential effectiveness
7168-407: Is more common in preadolescent children, with most cases caused by kidney disease . Primary or essential hypertension is more common in adolescents and adults and has multiple risk factors, including obesity and a family history of hypertension. Initial assessment upon diagnosis of hypertension should include a complete history and physical examination . The World Health Organization suggests
7296-521: Is not measured routinely in healthy newborns. Hypertension is more common in high risk newborns. A variety of factors, such as gestational age , postconceptional age and birth weight needs to be taken into account when deciding if a blood pressure is normal in a newborn. Hypertension defined as elevated blood pressure over several visits affects 1% to 5% of children and adolescents and is associated with long-term risks of ill-health. Blood pressure rises with age in childhood and, in children, hypertension
7424-464: Is often ceramic. For example, a continuous matrix, and a dispersed phase of ceramic particles or fibers. Applications of composite materials range from structural elements such as steel-reinforced concrete, to the thermally insulative tiles that play a key and integral role in NASA's Space Shuttle thermal protection system , which is used to protect the surface of the shuttle from the heat of re-entry into
7552-492: Is poor organ function. With the availability of 24-hour ambulatory blood pressure monitors and home blood pressure machines, the importance of not wrongly diagnosing those who have white coat hypertension has led to a change in protocols. In the United Kingdom, current best practice is to follow up a single raised clinic reading with ambulatory measurement, or less ideally with home blood pressure monitoring over
7680-492: Is present if the resting blood pressure is persistently at or above 130/80 or 140/90 mmHg. Different numbers apply to children. Ambulatory blood pressure monitoring over a 24-hour period appears more accurate than office-based blood pressure measurement . Lifestyle changes and medications can lower blood pressure and decrease the risk of health complications. Lifestyle changes include weight loss , physical exercise , decreased salt intake , reducing alcohol intake , and
7808-453: Is primarily protonated at the C3, rather than N1, owing to the enamine -like reactivity of the portion of the molecule located outside of the benzene ring. The protonated form has a p K a of −3.6. The sensitivity of many indolic compounds (e.g., tryptamines ) under acidic conditions is caused by this protonation. The most reactive position on indole for electrophilic aromatic substitution
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#17327658035917936-561: Is similar to and at times exceeds a single medication. If hypertension is high enough to justify immediate use of medications, lifestyle changes are still recommended in conjunction with medication. Dietary changes shown to reduce blood pressure include diets with low sodium, the DASH diet (Dietary Approaches to Stop Hypertension), which was the best against 11 other diet in an umbrella review, and plant-based diets. A 2024 clinical guideline recommended an increase dietary fiber intake, with
8064-510: Is the Fischer indole synthesis , developed in 1883 by Emil Fischer . Although the synthesis of indole itself is problematic using the Fischer indole synthesis, it is often used to generate indoles substituted in the 2- and/or 3-positions. Indole can still be synthesized, however, using the Fischer indole synthesis by reacting phenylhydrazine with pyruvic acid followed by decarboxylation of
8192-409: Is the ability of crystals to generate a voltage in response to an applied mechanical stress. The piezoelectric effect is reversible in that piezoelectric crystals, when subjected to an externally applied voltage, can change shape by a small amount. Polymer materials like rubber, wool, hair, wood fiber, and silk often behave as electrets . For example, the polymer polyvinylidene fluoride (PVDF) exhibits
8320-463: Is the most common secondary cause of hypertension. Hypertension can also be caused by endocrine conditions, such as Cushing's syndrome , hyperthyroidism , hypothyroidism , acromegaly , Conn's syndrome or hyperaldosteronism , renal artery stenosis (from atherosclerosis or fibromuscular dysplasia ), hyperparathyroidism , and pheochromocytoma . Other causes of secondary hypertension include obesity , sleep apnea , pregnancy , coarctation of
8448-400: Is the study of the behavior of solid matter under external actions such as external forces and temperature changes. A solid does not exhibit macroscopic flow, as fluids do. Any degree of departure from its original shape is called deformation . The proportion of deformation to original size is called strain. If the applied stress is sufficiently low, almost all solid materials behave in such
8576-429: Is typical of all people who ultimately develop hypertension is disputed. The increased peripheral resistance in established hypertension is mainly attributable to structural narrowing of small arteries and arterioles , although a reduction in the number or density of capillaries may also contribute. It is not clear whether or not vasoconstriction of arteriolar blood vessels plays a role in hypertension. Hypertension
8704-399: Is used as a secondary indicator of kidney disease. Lipid panel and glucose tests are done to identify comorbidities such as diabetes and hyperlipidemia and for cardiovascular risk stratification. Electrocardiogram (EKG/ECG) testing is done to check for evidence that the heart is under strain from high blood pressure, such as thickening of the heart muscle or whether the heart has experienced
8832-483: Is used in capacitors. A capacitor is an electrical device that can store energy in the electric field between a pair of closely spaced conductors (called 'plates'). When voltage is applied to the capacitor, electric charges of equal magnitude, but opposite polarity, build up on each plate. Capacitors are used in electrical circuits as energy-storage devices, as well as in electronic filters to differentiate between high-frequency and low-frequency signals. Piezoelectricity
8960-492: Is usually identified as part of health screening or when seeking healthcare for an unrelated problem. Some people with high blood pressure report headaches , as well as lightheadedness , vertigo , tinnitus (buzzing or hissing in the ears), altered vision or fainting episodes . These symptoms, however, might be related to associated anxiety rather than the high blood pressure itself. Long-standing untreated hypertension can cause organ damage with signs such as changes in
9088-403: Is when blood pressure increases upon standing. Once the diagnosis of hypertension has been made, further testing may be performed to find secondary hypertension , identify comorbidities such as diabetes , identify hypertension-caused organ damage such as chronic kidney disease or thickening of the heart muscle , and for cardiovascular disease risk stratification. Secondary hypertension
9216-740: The National Heart, Lung, and Blood Institute and American Academy of Pediatrics made a similar recommendation. However, the American Academy of Family Physicians supports the view of the U.S. Preventive Services Task Force that the available evidence is insufficient to determine the balance of benefits and harms of screening for hypertension in children and adolescents who do not have symptoms. The US Preventive Services Task Force recommends screening adults 18 years or older for hypertension with office blood pressure measurement. According to one review published in 2003, reduction of
9344-421: The betablocker pindolol . The name indole is a portmanteau of the words ind igo and ole um , since indole was first isolated by treatment of the indigo dye with oleum. Indole chemistry began to develop with the study of the dye indigo . Indigo can be converted to isatin and then to oxindole . Then, in 1866, Adolf von Baeyer reduced oxindole to indole using zinc dust. In 1869, he proposed
9472-432: The blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischemic heart disease by 21%, and reduce the likelihood of dementia , heart failure , and mortality from cardiovascular disease . Various expert groups have produced guidelines regarding how low the blood pressure target should be when a person is treated for hypertension. These groups recommend a target below the range 140–160 / 90–100 mmHg for
9600-559: The optic fundus seen by ophthalmoscopy . The severity of hypertensive retinopathy correlates roughly with the duration or the severity of the hypertension. Other hypertension-caused organ damage include chronic kidney disease and thickening of the heart muscle . Secondary hypertension is hypertension due to an identifiable cause, and may result in certain specific additional signs and symptoms. For example, as well as causing high blood pressure, Cushing's syndrome frequently causes truncal obesity , glucose intolerance , moon face ,
9728-513: The periodic table moving diagonally downward right from boron . They separate the electrical conductors (or metals, to the left) from the insulators (to the right). Devices made from semiconductor materials are the foundation of modern electronics, including radio, computers, telephones, etc. Semiconductor devices include the transistor , solar cells , diodes and integrated circuits . Solar photovoltaic panels are large semiconductor devices that directly convert light into electrical energy. In
9856-429: The sodium or potassium compounds tend to react with electrophiles at nitrogen-1, whereas the more covalent magnesium compounds ( indole Grignard reagents ) and (especially) zinc complexes tend to react at carbon 3 (see figure below). In analogous fashion, polar aprotic solvents such as DMF and DMSO tend to favour attack at the nitrogen, whereas nonpolar solvents such as toluene favour C3 attack. After
9984-481: The 2-aminofuran is the diene , whereas the indole is the dienophile . Indoles also undergo intramolecular [2+3] and [2+2] cycloadditions. Despite mediocre yields, intermolecular cycloadditions of indole derivatives have been well documented. One example is the Pictet-Spengler reaction between tryptophan derivatives and aldehydes , which produces a mixture of diastereomers , leading to reduced yield of
10112-452: The 2017 American Heart Association guidelines recommend medications if the systolic blood pressure is >140 mmHg or if the diastolic BP is >90 mmHg. For people who have experienced cardiovascular disease or those who are at a 10-year risk of cardiovascular disease of greater than 10%, it recommends medications if the systolic blood pressure is >130 mmHg or if the diastolic BP is >80 mmHg. The first line of treatment for hypertension
10240-457: The Earth's atmosphere. One example is Reinforced Carbon-Carbon (RCC), the light gray material that withstands reentry temperatures up to 1,510 °C (2,750 °F) and protects the nose cap and leading edges of Space Shuttle's wings. RCC is a laminated composite material made from graphite rayon cloth and impregnated with a phenolic resin . After curing at high temperature in an autoclave,
10368-511: The N–H proton, the hydrogen at C2 is the next most acidic proton on indole. Reaction of N -protected indoles with butyl lithium or lithium diisopropylamide results in lithiation exclusively at the C2 position. This strong nucleophile can then be used as such with other electrophiles. Bergman and Venemalm developed a technique for lithiating the 2-position of unsubstituted indole, as did Katritzky. Due to
10496-601: The absence of results from randomized controlled trials, the wisdom of reducing levels of dietary sodium intake below 3 g/day has been questioned. ESC guidelines mention periodontitis is associated with poor cardiovascular health status. The value of routine screening for hypertension is debated. In 2004, the National High Blood Pressure Education Program recommended that children aged 3 years and older have blood pressure measurement at least once at every health care visit and
10624-427: The aerospace industry, high performance materials used in the design of aircraft and/or spacecraft exteriors must have a high resistance to thermal shock. Thus, synthetic fibers spun out of organic polymers and polymer/ceramic/metal composite materials and fiber-reinforced polymers are now being designed with this purpose in mind. Because solids have thermal energy , their atoms vibrate about fixed mean positions within
10752-459: The aorta , excessive eating of liquorice , excessive drinking of alcohol, certain prescription medicines, herbal remedies, and stimulants such as cocaine and methamphetamine . A 2018 review found that any alcohol increased blood pressure in males while over one or two drinks increased the risk in females. In most people with established essential hypertension , increased resistance to blood flow ( total peripheral resistance ) accounts for
10880-444: The atoms in a solid can take a variety of forms. For example, a crystal of sodium chloride (common salt) is made up of ionic sodium and chlorine , which are held together by ionic bonds . In diamond or silicon, the atoms share electrons and form covalent bonds . In metals, electrons are shared in metallic bonding . Some solids, particularly most organic compounds, are held together with van der Waals forces resulting from
11008-464: The body. Through regular bouts of physical activity, blood pressure can reduce the incidence of hypertension. Aerobic exercise has been shown to regulate blood pressure more effectively than resistance training. It is recommended to see the effects of exercising, that a person should aim for 5-7 days/ week of aerobic exercise. This type of exercise should have an intensity of light to moderate, utilizing ~85% of max heart rate (220-age). Aerobic has shown
11136-890: The brain, kidney, heart and lungs, producing symptoms which may include confusion , drowsiness, chest pain and breathlessness. In hypertensive emergency, the blood pressure must be reduced more rapidly to stop ongoing organ damage; however, there is a lack of randomized controlled trial evidence for this approach. Hypertension occurs in approximately 8–10% of pregnancies. Two blood pressure measurements six hours apart of greater than 140/90 mmHg are diagnostic of hypertension in pregnancy. High blood pressure in pregnancy can be classified as pre-existing hypertension, gestational hypertension , or pre-eclampsia . Women who have chronic hypertension before their pregnancy are at increased risk of complications such as premature birth , low birthweight or stillbirth . Women who have high blood pressure and had complications in their pregnancy have three times
11264-663: The chemical bonds of the lignin before burning it out. One important property of carbon in organic chemistry is that it can form certain compounds, the individual molecules of which are capable of attaching themselves to one another, thereby forming a chain or a network. The process is called polymerization and the chains or networks polymers, while the source compound is a monomer. Two main groups of polymers exist: those artificially manufactured are referred to as industrial polymers or synthetic polymers (plastics) and those naturally occurring as biopolymers. Monomers can have various chemical substituents, or functional groups, which can affect
11392-467: The chemical properties of organic compounds, such as solubility and chemical reactivity, as well as the physical properties, such as hardness, density, mechanical or tensile strength, abrasion resistance, heat resistance, transparency, color, etc.. In proteins, these differences give the polymer the ability to adopt a biologically active conformation in preference to others (see self-assembly ). People have been using natural organic polymers for centuries in
11520-499: The course of 7 days. The United States Preventive Services Task Force also recommends getting measurements outside of the healthcare environment. Pseudohypertension in the elderly or noncompressibility artery syndrome may also require consideration. This condition is believed to be due to calcification of the arteries resulting in abnormally high blood pressure readings with a blood pressure cuff while intra arterial measurements of blood pressure are normal. Orthostatic hypertension
11648-419: The desired product. Indoles are susceptible to hydrogenation of the imine subunit to give indolines . Solid Solid is one of the four fundamental states of matter along with liquid , gas , and plasma . The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity (as in rigid bodies ) and resistance to
11776-543: The detection of extracellular and environmental indoles, are Salkowski , Kovács , Ehrlich’s reagent assays and HPLC . For intracellular indole detection and measurement genetically encoded indole-responsive biosensor is applicable. Indoles and their derivatives are promising against tuberculosis , malaria , diabetes , cancer , migraines , convulsions , hypertension , bacterial infections of methicillin-resistant Staphylococcus aureus ( MRSA ) and even viruses . Indole and its derivatives can also be synthesized by
11904-600: The disease burden of high blood pressure is experienced by people who are not labeled as hypertensive. Consequently, population strategies are required to reduce the consequences of high blood pressure and reduce the need for antihypertensive medications. Lifestyle changes are recommended to lower blood pressure. Recommended lifestyle changes for the prevention of hypertension include: Effective lifestyle modification may lower blood pressure as much as an individual antihypertensive medication. Combinations of two or more lifestyle modifications can achieve even better results. There
12032-411: The early 1980s, Toyota researched production of an adiabatic ceramic engine with an operating temperature of over 6,000 °F (3,320 °C). Ceramic engines do not require a cooling system and hence allow a major weight reduction and therefore greater fuel efficiency. In a conventional metallic engine, much of the energy released from the fuel must be dissipated as waste heat in order to prevent
12160-568: The effects of hypertension just after one bout of exercise. Exercising can help reduce hypertension as well as pre-eclampsia and eclampsia. The acute physiological responses include an increase in cardiac output (CO) of the individual (increased heart rate and stroke volume). This increase in CO can inadvertently maintain the amount of blood going into the muscles, improving functionality of the muscle later. Exercising can also improve systolic and diastolic blood pressure making it easier for blood to pump to
12288-514: The electron-rich nature of indole, it is easily oxidized . Simple oxidants such as N -bromosuccinimide will selectively oxidize indole 1 to oxindole ( 4 and 5 ). Only the C2–C3 pi bond of indole is capable of cycloaddition reactions . Intramolecular variants are often higher-yielding than intermolecular cycloadditions. For example, Padwa et al. have developed this Diels-Alder reaction to form advanced strychnine intermediates. In this case,
12416-578: The extreme hardness of zirconia is utilized in the manufacture of knife blades, as well as other industrial cutting tools. Ceramics such as alumina , boron carbide and silicon carbide have been used in bulletproof vests to repel large-caliber rifle fire. Silicon nitride parts are used in ceramic ball bearings, where their high hardness makes them wear resistant. In general, ceramics are also chemically resistant and can be used in wet environments where steel bearings would be susceptible to oxidation (or rust). As another example of ceramic applications, in
12544-509: The following initial tests: serum electrolytes , serum creatinine , lipid panel , HbA1c or fasting glucose , urine dipstick and electrocardiogram (ECG/EKG). Serum creatinine is measured to assess for the presence of kidney disease, which can be either the cause or the result of hypertension. eGFR can also provide a baseline measurement of kidney function that can be used to monitor for side effects of certain anti-hypertensive drugs on kidney function. Testing of urine samples for protein
12672-433: The form of waxes and shellac , which is classified as a thermoplastic polymer. A plant polymer named cellulose provided the tensile strength for natural fibers and ropes, and by the early 19th century natural rubber was in widespread use. Polymers are the raw materials (the resins) used to make what are commonly called plastics. Plastics are the final product, created after one or more polymers or additives have been added to
12800-400: The formed indole-2-carboxylic acid. This has also been accomplished in a one-pot synthesis using microwave irradiation. Unlike most amines , indole is not basic : just like pyrrole , the aromatic character of the ring means that the lone pair of electrons on the nitrogen atom is not available for protonation. Strong acids such as hydrochloric acid can, however, protonate indole. Indole
12928-422: The general population. Cochrane reviews recommend similar targets for subgroups such as people with diabetes and people with prior cardiovascular disease. Additionally, Cochrane reviews have found that for older individuals with moderate to high cardiovascular risk, the benefits of trying to achieve a lower than standard blood pressure target (at or below 140/90 mmHg) are outweighed by the risk associated with
13056-535: The glass-ceramic has a net coefficient of thermal expansion close to zero. This type of glass-ceramic exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C. Glass ceramics may also occur naturally when lightning strikes the crystalline (e.g. quartz) grains found in most beach sand . In this case, the extreme and immediate heat of the lightning (~2500 °C) creates hollow, branching rootlike structures called fulgurite via fusion . Organic chemistry studies
13184-673: The gold slabs (1064 °C); and metallic nanowires are much stronger than the corresponding bulk metals. The high surface area of nanoparticles makes them extremely attractive for certain applications in the field of energy. For example, platinum metals may provide improvements as automotive fuel catalysts , as well as proton exchange membrane (PEM) fuel cells. Also, ceramic oxides (or cermets) of lanthanum , cerium , manganese and nickel are now being developed as solid oxide fuel cells (SOFC). Lithium, lithium-titanate and tantalum nanoparticles are being applied in lithium-ion batteries. Silicon nanoparticles have been shown to dramatically expand
13312-478: The high pressure while cardiac output remains normal. There is evidence that some younger people with prehypertension or 'borderline hypertension' have high cardiac output, an elevated heart rate and normal peripheral resistance, termed hyperkinetic borderline hypertension. These individuals may develop the typical features of established essential hypertension in later life as their cardiac output falls and peripheral resistance rises with age. Whether this pattern
13440-556: The incoming light prior to capture. Here again, surface area of the nanoparticles (and thin films) plays a critical role in maximizing the amount of absorbed radiation. Many natural (or biological) materials are complex composites with remarkable mechanical properties. These complex structures, which have risen from hundreds of million years of evolution, are inspiring materials scientists in the design of novel materials. Their defining characteristics include structural hierarchy, multifunctionality and self-healing capability. Self-organization
13568-540: The intervention. These findings may not be applicable to other populations. Many expert groups recommend a slightly higher target of 150/90 mmHg for those over somewhere between 60 and 80 years of age. The JNC 8 and American College of Physicians recommend the target of 150/90 mmHg for those over 60 years of age, but some experts within these groups disagree with this recommendation. Some expert groups have also recommended slightly lower targets in those with diabetes or chronic kidney disease , but others recommend
13696-448: The ions and the electron cloud. The large number of free electrons gives metals their high values of electrical and thermal conductivity. The free electrons also prevent transmission of visible light, making metals opaque, shiny and lustrous . More advanced models of metal properties consider the effect of the positive ions cores on the delocalised electrons. As most metals have crystalline structure, those ions are usually arranged into
13824-550: The kidneys' salt and water handling (particularly abnormalities in the intrarenal renin–angiotensin system ) or abnormalities of the sympathetic nervous system . These mechanisms are not mutually exclusive and it is likely that both contribute to some extent in most cases of essential hypertension. It has also been suggested that endothelial dysfunction and vascular inflammation may also contribute to increased peripheral resistance and vascular damage in hypertension. Interleukin 17 has garnered interest for its role in increasing
13952-499: The laminate is pyrolized to convert the resin to carbon, impregnated with furfural alcohol in a vacuum chamber, and cured/pyrolized to convert the furfural alcohol to carbon. In order to provide oxidation resistance for reuse capability, the outer layers of the RCC are converted to silicon carbide. Domestic examples of composites can be seen in the "plastic" casings of television sets, cell-phones and so on. These plastic casings are usually
14080-440: The major component is a metal are known as alloys . People have been using metals for a variety of purposes since prehistoric times. The strength and reliability of metals has led to their widespread use in construction of buildings and other structures, as well as in most vehicles, many appliances and tools, pipes, road signs and railroad tracks. Iron and aluminium are the two most commonly used structural metals. They are also
14208-418: The matrix properties. A synergism produces material properties unavailable from the individual constituent materials, while the wide variety of matrix and strengthening materials provides the designer with the choice of an optimum combination. Semiconductors are materials that have an electrical resistivity (and conductivity) between that of metallic conductors and non-metallic insulators. They can be found in
14336-408: The molecules in a gas are loosely packed. The branch of physics that deals with solids is called solid-state physics , and is the main branch of condensed matter physics (which also includes liquids). Materials science is primarily concerned with the physical and chemical properties of solids. Solid-state chemistry is especially concerned with the synthesis of novel materials, as well as
14464-734: The most abundant metals in the Earth's crust . Iron is most commonly used in the form of an alloy, steel, which contains up to 2.1% carbon , making it much harder than pure iron. Because metals are good conductors of electricity, they are valuable in electrical appliances and for carrying an electric current over long distances with little energy loss or dissipation. Thus, electrical power grids rely on metal cables to distribute electricity. Home electrical systems, for example, are wired with copper for its good conducting properties and easy machinability. The high thermal conductivity of most metals also makes them useful for stovetop cooking utensils. The study of metallic elements and their alloys makes up
14592-409: The ordered (or disordered) lattice. The spectrum of lattice vibrations in a crystalline or glassy network provides the foundation for the kinetic theory of solids . This motion occurs at the atomic level, and thus cannot be observed or detected without highly specialized equipment, such as that used in spectroscopy . Thermal properties of solids include thermal conductivity , which is the property of
14720-433: The polarization of the electronic charge cloud on each molecule. The dissimilarities between the types of solid result from the differences between their bonding. Metals typically are strong, dense, and good conductors of both electricity and heat . The bulk of the elements in the periodic table , those to the left of a diagonal line drawn from boron to polonium , are metals. Mixtures of two or more elements in which
14848-499: The production of polycrystalline transparent ceramics such as transparent alumina and alumina compounds for such applications as high-power lasers. Advanced ceramics are also used in the medicine, electrical and electronics industries. Ceramic engineering is the science and technology of creating solid-state ceramic materials, parts and devices. This is done either by the action of heat, or, at lower temperatures, using precipitation reactions from chemical solutions. The term includes
14976-436: The production of several other immune system chemical signals thought to be involved in hypertension such as tumor necrosis factor alpha , interleukin 1 , interleukin 6 , and interleukin 8 . Excessive sodium or insufficient potassium in the diet leads to excessive intracellular sodium, which contracts vascular smooth muscle, restricting blood flow and so increases blood pressure. Non-modulating essential hypertension
15104-439: The purification of raw materials, the study and production of the chemical compounds concerned, their formation into components, and the study of their structure, composition and properties. Mechanically speaking, ceramic materials are brittle, hard, strong in compression and weak in shearing and tension. Brittle materials may exhibit significant tensile strength by supporting a static load. Toughness indicates how much energy
15232-406: The risk of death of the baby around the time of birth . Usually there are no symptoms in pre-eclampsia and it is detected by routine screening. When symptoms of pre-eclampsia occur the most common are headache, visual disturbance (often "flashing lights"), vomiting, pain over the stomach, and swelling . Pre-eclampsia can occasionally progress to a life-threatening condition called eclampsia , which
15360-457: The risk of developing cardiovascular disease compared to women with normal blood pressure who had no complications in pregnancy. Pre-eclampsia is a serious condition of the second half of pregnancy and following delivery characterised by increased blood pressure and the presence of protein in the urine . It occurs in about 5% of pregnancies and is responsible for approximately 16% of all maternal deaths globally. Pre-eclampsia also doubles
15488-399: The same target as for the general population. The issue of what is the best target and whether targets should differ for high risk individuals is unresolved, although some experts propose more intensive blood pressure lowering than advocated in some guidelines. For people who have never experienced cardiovascular disease who are at a 10-year risk of cardiovascular disease of less than 10%,
15616-480: The science of identification and chemical composition . The atoms, molecules or ions that make up solids may be arranged in an orderly repeating pattern, or irregularly. Materials whose constituents are arranged in a regular pattern are known as crystals . In some cases, the regular ordering can continue unbroken over a large scale, for example diamonds, where each diamond is a single crystal . Solid objects that are large enough to see and handle are rarely composed of
15744-527: The solid state. The mechanical properties of materials describe characteristics such as their strength and resistance to deformation. For example, steel beams are used in construction because of their high strength, meaning that they neither break nor bend significantly under the applied load. Mechanical properties include elasticity , plasticity , tensile strength , compressive strength , shear strength , fracture toughness , ductility (low in brittle materials) and indentation hardness . Solid mechanics
15872-479: The storage capacity of lithium-ion batteries during the expansion/contraction cycle. Silicon nanowires cycle without significant degradation and present the potential for use in batteries with greatly expanded storage times. Silicon nanoparticles are also being used in new forms of solar energy cells. Thin film deposition of silicon quantum dots on the polycrystalline silicon substrate of a photovoltaic (solar) cell increases voltage output as much as 60% by fluorescing
16000-442: The structure, properties, composition, reactions, and preparation by synthesis (or other means) of chemical compounds of carbon and hydrogen , which may contain any number of other elements such as nitrogen , oxygen and the halogens: fluorine , chlorine , bromine and iodine . Some organic compounds may also contain the elements phosphorus or sulfur . Examples of organic solids include wood, paraffin wax , naphthalene and
16128-402: The synthetic precursors for) the tryptophan-derived tryptamine alkaloids, which includes the neurotransmitter serotonin and the hormone melatonin , as well as the naturally occurring psychedelic drugs dimethyltryptamine and psilocybin . Other indolic compounds include the plant hormone auxin (indolyl-3-acetic acid, IAA ), tryptophol , the anti-inflammatory drug indomethacin , and
16256-508: The temperature is lowered, but remains finite. In a superconductor, however, the resistance drops abruptly to zero when the material is cooled below its critical temperature. An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source. A dielectric , or electrical insulator, is a substance that is highly resistant to the flow of electric current. A dielectric, such as plastic, tends to concentrate an applied electric field within itself, which property
16384-464: The wear plates of crushing equipment in mining operations. Most ceramic materials, such as alumina and its compounds, are formed from fine powders, yielding a fine grained polycrystalline microstructure that is filled with light-scattering centers comparable to the wavelength of visible light . Thus, they are generally opaque materials, as opposed to transparent materials . Recent nanoscale (e.g. sol-gel ) technology has, however, made possible
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