Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.
A trace element that constitutes about 27.6% of the earth's crust in the form of SILICON DIOXIDE. It does not occur free in nature. Silicon has the atomic symbol Si, atomic number 14, and atomic weight [28.084; 28.086].
Hafnium. A metal element of atomic number 72 and atomic weight 178.49, symbol Hf. (From Dorland, 28th ed)
A technique of measuring the dielectric properties of materials, which vary over a range of frequencies depending on the physical properties of the material. The technique involves measuring, over a range of frequencies, ELECTRICAL IMPEDANCE and phase shift of an electric field as it passes through the material.
The branch of medicine concerned with the application of NANOTECHNOLOGY to the prevention and treatment of disease. It involves the monitoring, repair, construction, and control of human biological systems at the molecular level, using engineered nanodevices and NANOSTRUCTURES. (From Freitas Jr., Nanomedicine, vol 1, 1999).
Inorganic compounds that contain silicon as an integral part of the molecule.
Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
Inorganic compounds that contain carbon as an integral part of the molecule but are not derived from hydrocarbons.
Nitrogen oxide (NO2). A highly poisonous gas. Exposure produces inflammation of lungs that may only cause slight pain or pass unnoticed, but resulting edema several days later may cause death. (From Merck, 11th ed) It is a major atmospheric pollutant that is able to absorb UV light that does not reach the earth's surface.
Nanometer-scale wires made of materials that conduct electricity. They can be coated with molecules such as antibodies that will bind to proteins and other substances.
A highly toxic, colorless, nonflammable gas. It is used as a pharmaceutical aid and antioxidant. It is also an environmental air pollutant.
Materials that have a limited and usually variable electrical conductivity. They are particularly useful for the production of solid-state electronic devices.
Organic compounds that contain silicon as an integral part of the molecule.
The development and use of techniques to study physical phenomena and construct structures in the nanoscale size range or smaller.

Personal exposure to dust, endotoxin and crystalline silica in California agriculture. (1/2325)

AIMS: The aim of this study was to measure personal exposure to dust, endotoxin and crystalline silica during various agricultural operations in California over a period of one year. METHODS: Ten farms were randomly selected in Yolo and Solano counties and workers were invited to wear personal sampling equipment to measure inhalable and respirable dust levels during various operations. The samples were analysed for endotoxin using the Limulus Amebocyte Lysate assay and crystalline silica content using X-ray diffraction. In total 142 inhalable samples and 144 respirable samples were collected. RESULTS: The measurements showed considerable difference in exposure levels between various operations, in particular for the inhalable fraction of the dust and the endotoxin. Machine harvesting of tree crops (Geometric mean (GM) = 45.1 mg/m3) and vegetables (GM = 7.9 mg/m3), and cleaning of poultry houses (GM = 6.7 mg/m3) showed the highest inhalable dust levels. Cleaning of poultry houses also showed the highest inhalable endotoxin levels (GM = 1861 EU/m3). Respirable dust levels were generally low, except for machine harvesting of tree crops (GM = 2.8 mg/m3) and vegetables (GM = 0.9 mg/m3). Respirable endotoxin levels were also low. For the inhalable dust fraction, levels were reduced considerably when an enclosed cabin was present. The percentage of crystalline silica was overall higher in the respirable dust samples than the inhalable dust samples. CONCLUSIONS: Considerable differences exist in personal exposure levels to dust, endotoxin and crystalline silica during various agricultural operations in California agriculture with some operations showing very high levels.  (+info)

Purification and characterization of rat hippocampal CA3-dendritic spines associated with mossy fiber terminals. (2/2325)

We report a revised and improved isolation procedure for CA3-dendritic spines, most of them still in association with mossy fiber terminals resulting in a 7.5-fold enrichment over nuclei and a 29-fold enrichment over myelin. Additionally, red blood cells, medullated fibers, mitochondria and small synaptosomes were significantly depleted. We show by high resolution electron microscopy that this subcellular fraction contains numerous dendritic spines with a rich ultrastructure, e.g. an intact spine apparatus, membranous organelles, free and membrane-bound polyribosomes, endocytic structures and mitochondria. This improved experimental system will allow us to study aspects of post-synaptic functions at the biochemical and molecular level.  (+info)

Silica dust and lung cancer in the German stone, quarrying, and ceramics industries: results of a case-control study. (3/2325)

BACKGROUND: A work force based case-control study of lung cancer was performed in non-silicotic subjects exposed to crystalline silica to investigate the association between silica dust and lung cancer excluding the influence of silicosis. METHODS: Two hundred and forty seven patients with lung cancer and 795 control subjects were enrolled, all of whom had been employed in the German stone, quarrying, or ceramics industries. Smoking was used as a matching criterion. Exposure to silica was quantified by measurements, if available, or otherwise by industrial hygienists. Several indices (peak, average and cumulative exposure) were used to analyse the relationship between the level of exposure and risk of lung cancer as odds ratios (OR). RESULTS: The risk of lung cancer is associated with the year of and age at first exposure to silica, duration of exposure, and latency. All odds ratios were adjusted for these factors. Considering the peak exposure, the OR for workers exposed to high levels (>/=0.15 mg/m3 respirable silica dust which is the current occupational threshold value for Germany) compared with those exposed to low levels (<0.15 mg/m3) was 0.85 (95% CI 0.58 to 1. 25). For the time weighted average exposure the OR was 0.91 (95% CI 0.57 to 1.46). The OR for the cumulative exposure was 1.02 (95% CI 0. 67 to 1.55). No increase in risk was evident with increasing exposure. CONCLUSIONS: This study shows no association between exposure to crystalline silica and lung cancer. The exclusion of subjects with silicosis may have led to dilution with respect to the level of exposure and therefore reduced the power to detect a small risk. Alternatively, the risk of getting lung cancer may be restricted to subjects with silicosis and is not directly linked to silica dust.  (+info)

Biochemical evolution III: polymerization on organophilic silica-rich surfaces, crystal-chemical modeling, formation of first cells, and geological clues. (4/2325)

Catalysis at organophilic silica-rich surfaces of zeolites and feldspars might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and other geological sources. Crystal-chemical modeling yielded packings for amino acids neatly encapsulated in 10-ring channels of the molecular sieve silicalite-ZSM-5-(mutinaite). Calculation of binding and activation energies for catalytic assembly into polymers is progressing for a chemical composition with one catalytic Al-OH site per 25 neutral Si tetrahedral sites. Internal channel intersections and external terminations provide special stereochemical features suitable for complex organic species. Polymer migration along nano/micrometer channels of ancient weathered feldspars, plus exploitation of phosphorus and various transition metals in entrapped apatite and other microminerals, might have generated complexes of replicating catalytic biomolecules, leading to primitive cellular organisms. The first cell wall might have been an internal mineral surface, from which the cell developed a protective biological cap emerging into a nutrient-rich "soup." Ultimately, the biological cap might have expanded into a complete cell wall, allowing mobility and colonization of energy-rich challenging environments. Electron microscopy of honeycomb channels inside weathered feldspars of the Shap granite (northwest England) has revealed modern bacteria, perhaps indicative of Archean ones. All known early rocks were metamorphosed too highly during geologic time to permit simple survival of large-pore zeolites, honeycombed feldspar, and encapsulated species. Possible microscopic clues to the proposed mineral adsorbents/catalysts are discussed for planning of systematic study of black cherts from weakly metamorphosed Archaean sediments.  (+info)

Presence of Campylobacter and Salmonella in sand from bathing beaches. (5/2325)

The purpose of this study was to determine the presence of thermophilic Campylobacter spp. and Salmonella spp. in sand from non-EEC standard and EEC standard designated beaches in different locations in the UK and to assess if potentially pathogenic strains were present. Campylobacter spp. were detected in 82/182 (45%) of sand samples and Salmonella spp. in 10/182 (6%). Campylobacter spp. were isolated from 46/92 (50%) of samples from non-EEC standard beaches and 36/90 (40%) from EEC standard beaches. The prevalence of Campylobacter spp. was greater in wet sand from both types of beaches but, surprisingly, more than 30% of samples from dry sand also contained these organisms. The major pathogenic species C. jejuni and C. coli were more prevalent in sand from non-EEC standard beaches. In contrast, C. lari and urease positive thermophilic campylobacters, which are associated with seagulls and other migratory birds, were more prevalent in sand from EEC standard beaches. Campylobacter isolates were further characterized by biotyping and serotyping, which confirmed that strains known to be of types associated with human infections were frequently found in sand on bathing beaches.  (+info)

Immature germ cell separation using a modified discontinuous Percoll gradient technique in human semen. (6/2325)

The difficulty of identifying immature germ cells in unstained, fresh semen has led most laboratories to use the broad definition 'round cells' to indicate cells other than spermatozoa, thus grouping together both leukocytes and immature germ cells. This is also the case in research andrology, where very little attention has been given to immature germ cells in the semen apart from some rare exceptions, such as the attempts to study meiosis. Here we report on the use of a discontinuous Percoll gradient method modified to enable the best separation possible of immature germ cells from the other cells found in the ejaculate, in order to obtain a cellular suspension free of spermatozoa. Our technique (intra-assay variation in duplicates < 10%) demonstrated a high immature germ cell concentration in gradient fractions with 30% to 45% Percoll with a small contamination (1.5-6%) of leukocytes, confirmed by May-Grunwald-Giemsa staining, immunofluorescence and cytofluorimetry. The concentrations of immature germ cells ranged from zero in obstructive azoospermia to 2.0 x 10(6)/ml in oligozoospermia and genital tract infection. The purified immature germ cell suspensions obtained can be useful for diagnostic and research purposes.  (+info)

Comparative evaluation of two density gradient preparations for sperm separation for medically assisted conception. (7/2325)

To evaluate and optimize the sperm separation efficiency of a novel silane-coated silica bead (Puresperm), serial studies were carried out to compare the various sperm parameters between: (i) three-layer (90%-70%-40%) Puresperm and three-layer (90%-70%-40%) conventional polyvinylpyrrolidone (PVP)-coated silica bead (Percoll) gradients; (ii) three-layer (90%-70%-40%) and two-layer (90%-45%) Puresperm gradients and separately the same for Percoll; and (iii) large (3.0 ml) and small (0.75 ml) semen loading volumes on three-layer Puresperm gradients. Normozoospermic semen samples were treated and analysed in 12 replicates for each experiment. Manual evaluation of concentration, percentage motility, percentage vitality, percentage normal morphology; computer-assisted semen analysis evaluation of concentration, percentage motility, grade of motility, motion characteristics (curvilinear velocity, linearity, amplitude of lateral head velocity, beat cross frequency, percentage hyperactivation); and yields from the initial semen samples were compared. Percoll was found to be superior to Puresperm in concentration, percentage motility, percentage vitality and yields after three-layer density gradient centrifugation. There were no significant differences in sperm parameters between two- and three-layer Percoll gradients, but three-layer Puresperm gradients behaved significantly better than two-layer gradients. Large semen volume loads on three-layer Puresperm gradients resulted in greater sperm concentrations, percentage motility, percentage vitality and percentage normal morphology, but small semen volume loads produced greater yields of good-quality spermatozoa. In the light of Percoll being withdrawn from the shelf for the use of assisted reproduction because of the presence of PVP, three-layer Puresperm gradients with large semen loading volumes appear to be an attractive alternative for sperm separation in medically assisted conception.  (+info)

A post-stishovite SiO2 polymorph in the meteorite Shergotty: implications for impact events. (8/2325)

Transmission electron microscopy and electron diffraction show that the martian meteorite Shergotty, a shocked achondrite, contains a dense orthorhombic SiO2 phase similar to post-stishovite SiO2 with the alpha-PbO2 structure. If an SiO2 mineral exists in Earth's lower mantle, it would probably occur in a post-stishovite SiO2 structure. The presence of such a high-density polymorph in a shocked sample indicates that post-stishovite SiO2 structures may be used as indicators of extreme shock pressures.  (+info)

Silicon dioxide is not a medical term, but a chemical compound with the formula SiO2. It's commonly known as quartz or sand and is not something that would typically have a medical definition. However, in some cases, silicon dioxide can be used in pharmaceutical preparations as an excipient (an inactive substance that serves as a vehicle or medium for a drug) or as a food additive, often as an anti-caking agent.

In these contexts, it's important to note that silicon dioxide is considered generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA). However, exposure to very high levels of respirable silica dust, such as in certain industrial settings, can increase the risk of lung disease, including silicosis.

I'm sorry for any confusion, but "Silicon" does not have a specific medical definition. Silicon is a chemical element with the symbol Si and atomic number 14. It is a metalloid, which means it has properties of both metals and nonmetals. In the human body, silicon is not considered an essential nutrient, although it is found in trace amounts in various tissues. Some research suggests that silicon might play a role in collagen synthesis and bone health, but more studies are needed to confirm these findings and establish recommended intake levels.

I'm sorry for any confusion, but Hafnium is not a medical term. It is a chemical element with the symbol Hf and atomic number 72. Hafnium is a lustrous, silvery, tetravalent transition metal that chemically resembles zirconium and is found in zirconium minerals.

It has no relevance to medical terminology or healthcare. If you have any questions related to medical definitions or health-related topics, I'd be happy to try to help with those instead!

Dielectric spectroscopy is a type of material characterization technique that measures the dielectric properties of a material as a function of frequency. The dielectric property of a material refers to its ability to store electrical energy in the form of polarization when an external electric field is applied. In dielectric spectroscopy, the material's response to an alternating electric field is measured, and the resulting complex permittivity (which includes both real and imaginary components) is used to characterize the material's dielectric behavior.

The technique involves applying a small amplitude AC voltage to the material while measuring the current flow through it. The frequency of the applied voltage can be varied over a wide range, typically from millihertz to gigahertz. By analyzing the phase shift and amplitude of the resulting current, the complex permittivity of the material can be determined as a function of frequency.

Dielectric spectroscopy is widely used in materials science, physics, chemistry, and biology to study the structure, dynamics, and composition of various materials, including polymers, ceramics, glasses, colloids, and biological tissues. The technique can provide valuable information about the material's molecular mobility, relaxation processes, conductivity, and other dielectric properties, which can be used for quality control, process monitoring, and fundamental research.

Nanomedicine is a branch of medicine that utilizes nanotechnology, which deals with materials, devices, or systems at the nanometer scale (typically between 1-100 nm), to prevent and treat diseases. It involves the development of novel therapeutics, diagnostics, and medical devices that can interact with biological systems at the molecular level for improved detection, monitoring, and targeted treatment of various diseases and conditions.

Nanomedicine encompasses several areas, including:

1. Drug delivery: Nanocarriers such as liposomes, polymeric nanoparticles, dendrimers, and inorganic nanoparticles can be used to encapsulate drugs, enhancing their solubility, stability, and targeted delivery to specific cells or tissues, thereby reducing side effects.
2. Diagnostics: Nanoscale biosensors and imaging agents can provide early detection and monitoring of diseases with high sensitivity and specificity, enabling personalized medicine and improved patient outcomes.
3. Regenerative medicine: Nanomaterials can be used to create scaffolds and matrices for tissue engineering, promoting cell growth, differentiation, and vascularization in damaged or diseased tissues.
4. Gene therapy: Nanoparticles can be employed to deliver genetic material such as DNA, RNA, or gene-editing tools (e.g., CRISPR-Cas9) for the targeted correction of genetic disorders or cancer treatment.
5. Medical devices: Nanotechnology can improve the performance and functionality of medical devices by enhancing their biocompatibility, strength, and electrical conductivity, as well as incorporating sensing and drug delivery capabilities.

Overall, nanomedicine holds great promise for addressing unmet medical needs, improving diagnostic accuracy, and developing more effective therapies with reduced side effects. However, it also presents unique challenges related to safety, regulation, and scalability that must be addressed before widespread clinical adoption.

Silicon compounds refer to chemical substances that contain the element silicon (Si) combined with other elements. Silicon is a Group 14 semimetal in the periodic table, and it often forms compounds through covalent bonding. The most common silicon compound is silicon dioxide (SiO2), also known as silica, which is found in nature as quartz, sand, and other minerals.

Silicon can form compounds with many other elements, including hydrogen, oxygen, halogens, sulfur, nitrogen, and carbon. For example:

* Silanes (SiHn) are a series of silicon-hydrogen compounds where n ranges from 1 to 6.
* Silicones are synthetic polymers made up of alternating silicon and oxygen atoms with organic groups attached to the silicon atoms.
* Silicates are a class of minerals that contain silicon, oxygen, and one or more metal cations. They have a wide range of structures and uses, including as building materials, ceramics, and glass.
* Siloxanes are a group of compounds containing alternating silicon-oxygen bonds with organic groups attached to the silicon atoms.

Silicon compounds have various applications in industry, medicine, and daily life. For instance, silicones are used in medical devices such as breast implants, contact lenses, and catheters due to their biocompatibility and flexibility. Silicates are found in pharmaceuticals, cosmetics, and food additives. Silicon-based materials are also used in dental restorations, bone cement, and drug delivery systems.

Nanoparticles are defined in the field of medicine as tiny particles that have at least one dimension between 1 to 100 nanometers (nm). They are increasingly being used in various medical applications such as drug delivery, diagnostics, and therapeutics. Due to their small size, nanoparticles can penetrate cells, tissues, and organs more efficiently than larger particles, making them ideal for targeted drug delivery and imaging.

Nanoparticles can be made from a variety of materials including metals, polymers, lipids, and dendrimers. The physical and chemical properties of nanoparticles, such as size, shape, charge, and surface chemistry, can greatly affect their behavior in biological systems and their potential medical applications.

It is important to note that the use of nanoparticles in medicine is still a relatively new field, and there are ongoing studies to better understand their safety and efficacy.

Carbon dioxide (CO2) is a colorless, odorless gas that is naturally present in the Earth's atmosphere. It is a normal byproduct of cellular respiration in humans, animals, and plants, and is also produced through the combustion of fossil fuels such as coal, oil, and natural gas.

In medical terms, carbon dioxide is often used as a respiratory stimulant and to maintain the pH balance of blood. It is also used during certain medical procedures, such as laparoscopic surgery, to insufflate (inflate) the abdominal cavity and create a working space for the surgeon.

Elevated levels of carbon dioxide in the body can lead to respiratory acidosis, a condition characterized by an increased concentration of carbon dioxide in the blood and a decrease in pH. This can occur in conditions such as chronic obstructive pulmonary disease (COPD), asthma, or other lung diseases that impair breathing and gas exchange. Symptoms of respiratory acidosis may include shortness of breath, confusion, headache, and in severe cases, coma or death.

Carbon inorganic compounds are chemical substances that contain carbon combined with one or more elements other than hydrogen. These compounds include oxides of carbon such as carbon monoxide (CO) and carbon dioxide (CO2), metal carbides like calcium carbide (CaC2) and silicon carbide (SiC), and carbonates like calcium carbonate (CaCO3) and sodium carbonate (Na2CO3).

Unlike organic compounds, which are based on carbon-hydrogen bonds, inorganic carbon compounds do not contain hydrocarbon structures. Instead, they feature carbon bonded to elements such as nitrogen, oxygen, sulfur, or halogens. Inorganic carbon compounds have diverse physical and chemical properties and play important roles in various industrial applications, as well as in biological systems.

Nitrogen dioxide (NO2) is a gaseous air pollutant and respiratory irritant. It is a reddish-brown toxic gas with a pungent, choking odor. NO2 is a major component of smog and is produced from the combustion of fossil fuels in vehicles, power plants, and industrial processes.

Exposure to nitrogen dioxide can cause respiratory symptoms such as coughing, wheezing, and difficulty breathing, especially in people with asthma or other respiratory conditions. Long-term exposure has been linked to the development of chronic lung diseases, including bronchitis and emphysema. NO2 also contributes to the formation of fine particulate matter (PM2.5), which can penetrate deep into the lungs and cause additional health problems.

I'm sorry for any confusion, but "nanowires" is not a medical term. It is a term used in the field of materials science and nanotechnology. Nanowires are one-dimensional structures with a diameter of 1-100 nanometers (nm) and an aspect ratio (length/diameter) greater than 1000. They have unique electrical, mechanical, and optical properties that make them useful in various applications such as electronics, sensors, energy storage, and biomedical devices.

Sulfur dioxide (SO2) is not a medical term per se, but it's an important chemical compound with implications in human health and medicine. Here's a brief definition:

Sulfur dioxide (SO2) is a colorless gas with a sharp, pungent odor. It is primarily released into the atmosphere as a result of human activities such as the burning of fossil fuels (like coal and oil) and the smelting of metals. SO2 is also produced naturally during volcanic eruptions and some biological processes.

In medical terms, exposure to high levels of sulfur dioxide can have adverse health effects, particularly for people with respiratory conditions like asthma or chronic obstructive pulmonary disease (COPD). SO2 can irritate the eyes, nose, throat, and lungs, causing coughing, wheezing, shortness of breath, and a tight feeling in the chest. Prolonged exposure to elevated levels of SO2 may exacerbate existing respiratory issues and lead to decreased lung function.

Regulations are in place to limit sulfur dioxide emissions from industrial sources to protect public health and reduce air pollution.

I'm sorry for any confusion, but "semiconductors" is a term from the field of materials science and electronics rather than medicine. Semiconductors are materials, often silicon-based, that have properties between conductors and insulators. They are used in various electronic devices due to their unique property of controlling the flow of electrical current. If you have any medical questions, I'd be happy to help with those instead!

Organosilicon compounds are a class of chemical compounds that contain at least one organic group (a group of atoms composed mainly of carbon and hydrogen) bonded to a silicon atom. The organic group can be an alkyl group, aryl group, or any other group that is derived from a hydrocarbon.

The term "organosilicon" is used to describe the covalent bond between carbon and silicon atoms, which is a type of bond known as a "sigma bond." This bond is formed by the overlap of atomic orbitals between the carbon and silicon atoms. The resulting organosilicon compound can have a wide range of physical and chemical properties, depending on the nature of the organic group and the number of such groups attached to the silicon atom.

Organosilicon compounds are widely used in various industries, including electronics, coatings, adhesives, and pharmaceuticals. They are also used as intermediates in the synthesis of other chemical compounds. Some common examples of organosilicon compounds include silicones, which are polymers that contain repeating units of siloxane (Si-O-Si) bonds, and organofunctional silanes, which are used as coupling agents to improve the adhesion of materials to surfaces.

Nanotechnology is not a medical term per se, but it is a field of study with potential applications in medicine. According to the National Nanotechnology Initiative, nanotechnology is defined as "the understanding and control of matter at the nanoscale, at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications."

In the context of medicine, nanotechnology has the potential to revolutionize the way we diagnose, treat, and prevent diseases. Nanomedicine involves the use of nanoscale materials, devices, or systems for medical applications. These can include drug delivery systems that target specific cells or tissues, diagnostic tools that detect biomarkers at the molecular level, and tissue engineering strategies that promote regeneration and repair.

While nanotechnology holds great promise for medicine, it is still a relatively new field with many challenges to overcome, including issues related to safety, regulation, and scalability.

... could be grown on a silicon semiconductor surface. Silicon oxide layers could protect silicon surfaces during ... HF is used to remove or pattern silicon dioxide in the semiconductor industry. Silicon dioxide acts as a Lux-Flood acid, being ... Silicon dioxide has been researched for agricultural applications as a potential insecticide. Silicon dioxide is mostly ... Colloidal silicon dioxide Dicalite DRI-DIE Insecticide 67 FLO-GARD Fossil flour Fumed silica Fumed silicon dioxide HI-SEL LO- ...
... silicon dioxide. Berlinite looks like quartz and has a structure that is similar to quartz with silicon replaced by Al and P. ... and this mirrors the behaviour of silicon dioxide. There are many types of aluminium phosphate molecular sieves, generically ...
The Silicon Engine. Computer History Museum. Retrieved 29 July 2019. Atalla, M.; Kahng, D. (1960). "Silicon-silicon dioxide ...
The devices have been dubbed "one diode-one resistor" (1D-1R). One implementation uses a silicon dioxide chip. As in most ... Orphaned articles from December 2013, All orphaned articles, Types of RAM, Silicon dioxide, Diodes). ... When electricity passes through a layer of silicon oxide, it strips away oxygen molecules and creates a channel of pure ... metallic-phase silicon less than five nanometers wide. The diodes eliminate the crosstalk inherent in crossbar structures by ...
Its silicon dioxide content is over 66%. The park has 101 major geological relics and 24 water views. In the geomorphic ...
p. 4. ISBN 0-471-33372-7. Atalla, Mohamed M.; Kahng, Dawon (June 1960). "Silicon-silicon dioxide field induced surface devices ... The i1103 was manufactured on a 6-mask silicon-gate P-MOS process with 8 μm minimum features. The resulting product had a 2,400 ... "IBM claims world's smallest silicon transistor - TheINQUIRER". Theinquirer.net. 2002-12-09. Archived from the original on May ... "Observation of electron velocity overshoot in sub-100-nm-channel MOSFET's in Silicon". IEEE Electron Device Letters. 6 (12): ...
Derick accidentally grew a layer of silicon dioxide over the silicon wafer. Further research showed that silicon dioxide could ... Silicon dioxide has traditionally been used as the gate insulator. Silicon dioxide however has a modest dielectric constant. ... Atalla, M.; Kahng, D. (1960). "Silicon-silicon dioxide field induced surface devices". IRE-AIEE Solid State Device Research ... traditionally of silicon dioxide and later of silicon oxynitride. Some companies use a high-κ dielectric and metal gate ...
The Silicon Engine. Computer History Museum. Atalla, M.; Kahng, D. (1960). "Silicon-silicon dioxide field induced surface ... Thermally oxidized silicon is a traditional substrate for OFETs where the silicon dioxide serves as the gate insulator. The ... This pentacene oxidation technique is akin to the silicon oxidation used in the silicon electronics. Polycrystalline ... The performance of OFETs, which can compete with that of amorphous silicon (a-Si) TFTs with field-effect mobilities of 0.5-1 ...
Atalla, M.; Kahng, D. (1960). "Silicon-silicon dioxide field induced surface devices". IRE-AIEE Solid State Device Research ... "1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated". The Silicon Engine. Computer History Museum. Retrieved 29 July ...
Silicon dioxide, History of agriculture, Natufian culture). ...
Zhang LM (2012-01-01). "Near-field spectroscopy of silicon dioxide thin films". Physical Review B. 85 (7): 075419. arXiv: ...
... polymorph of silicon dioxide, silica. It is an ultrafine powder collected as a by-product of the silicon and ferrosilicon alloy ... Wikimedia Commons has media related to Silicon dioxide. Silica Fume Association (Articles with short description, Short ... Early research used an expensive additive called fumed silica, an amorphous form of silica made by combustion of silicon ... With the implementation of tougher environmental laws during the mid-1970s, silicon smelters began to collect the silica fume ...
Silicon dioxide is the principal constituent of sand. As Carbon is to Biology, Silicon is to Geology. Phosphorus (P) is a ... Silicon (Si) is a metalloid. It is a semiconductor, making it the principal component in many integrated circuits. ...
Silica or silicon dioxide is a chemical compound. Silica may also refer to: Silica gel, a desiccant Silica, Rožňava District, ...
"Kaso Mine, Kanuma City, Tochigi, Japan". Kaso Mine (Manganese, Silicon Dioxide) - Imai, Genichiro, Tochigi. 1947. "Oukura mine ...
Simethicone is a mixture of dimethicone and silicon dioxide. The INN name is "simeticone", which was added to the INN ... Silicon, Silicon dioxide, Digestive system, Silicones). ...
Oxidation of organosilicon compounds, including siloxanes, gives silicon dioxide. This conversion is illustrated by the ... Polysiloxanes (silicones), upon combustion in an inert atmosphere, generally undergo pyrolysis to form silicon oxycarbide or ... "The inertness of silicones toward warmblooded animals has been demonstrated in a number of tests." With an LD50 in rats of >50 ... The main route to siloxane functional group is by hydrolysis of silicon chlorides: 2 R3Si−Cl + H2O → R3Si−O−SiR3 + 2 HCl The ...
Silification is the replacement of rock by silicon dioxide. A diapir is a rock formation, which owing to having a lower density ... The summit fumaroles have temperatures of less than 80 °C (176 °F). Their gases contain large quantities of carbon dioxide, ... water and larger amounts of hydrogen sulfide than sulfur dioxide perhaps due to the latter being filtered out by a hydrothermal ...
... a silicon dioxide polymer. These inorganic structures provide support for the animals. Silica deposition begins intracellularly ... Silicateins are enzymes which catalyse the formation of biosilica from monomeric silicon compounds (such as silicic acid) ... and mechanistic catalysts for the polycondensation reactions of silicon-compounds. The Venus' flower basket siliceous sponge is ... https://doi.org/10.1073/pnas.95.11.6234 Bullis, Kevin (1 November 2006). "Silicon and Sun". MIT Technology Review. Retrieved 6 ...
"Carbon dioxide absorption spectroscopy with a mid-infrared silicon photonic waveguide". Optics Letters. 45 (1): 109. arXiv: ... "Carbon dioxide 화학공학소재연구정보센터(CHERIC) , 연구정보 , KDB , Pure Component Properties". www.cheric.org. Giauque, W. F.; Egan, C. J. ( ... MSDS for solid carbon dioxide is available from Pacific Dry Ice, inc. ‡Second column of table indicates solubility at each ... Because nitrogen and oxygen are symmetrical and carbon dioxide and water vapor are not, the air in an infrared ...
"Infrared studies on polymorphs of silicon dioxide and germanium dioxide". Journal of Research of the National Bureau of ...
Commonly, hydrogen fluoride and xenon difluorides are used to etch silicon dioxide and silicon sacrificial layers respectively ... J. Holmes, P.J Snell (1966). "A vapour etching technique for the photolithography of silicon dioxide". Microelectronics and ... 2 XeF2 (abs) + Si (s) → 2 Xe (g) + 2 F (abs) + Si (s) The fluorine bonds with the surface silicon to form silicon tetra ... After the etchant has been mass transported to the silicon surface, the xenon difluoride is absorbed on the silicon surface. 2 ...
It is one of several forms (polymorphs) of silicon dioxide. It is a white solid. It consists of tetrahedral silicon centers and ... Unlike conventional polymorphs of titanium dioxide, the Ti centers in titanium silicalite have tetrahedral coordination ...
The earliest gate dielectric used in a field-effect transistor was silicon dioxide (SiO2). The silicon and silicon dioxide ... For silicon-substrate FETs, the gate dielectric is almost always silicon dioxide (called "gate oxide"), since thermal oxide has ... Silicon dioxide remains the standard gate dielectric in MOSFET technology. QBD (electronics) Kooi†, E.; Schmitz, A. (2005). " ...
Silicon dioxide can be fatal and carbon dioxide is not. Moving forward in this chapter Kean starts to describe Germanium and ... Next, Kean describes silicon. In general, he states that they are cousins because silicon mimics carbon in the sense that it ... The big issue that silicon encounters is that silicon does not have the life-sustaining abilities like carbon to attach to ... Unfortunately for Germanium, silicon provided a much better use for electronics and was used when men were sent to the moon and ...
Subsequently, a pattern of silicon dioxide is defined by LON. The SMM molecules are predominantly deposited on the oxide ... first observed by Dagata and co-workers in 1990 who locally modified a hydrogen-terminated silicon surface into silicon dioxide ... LON also allows to fabricate Silicon Nanowires (SiNWs) in a top-down fashion starting from silicon on insulator (SOI) wafers. ... this technique is compatible with the standard silicon CMOS processing technology. Single crystalline silicon nanowires have ...
"Effect of Nitridation of Silicon Dioxide on Its Infrared Spectrum". Journal of the Electrochemical Society. 131 (3): 637-640. ...
... and breakdown in silicon dioxide films on silicon". Journal of Applied Physics. AIP Publishing. 73 (7): 3367-3384. doi:10.1063/ ... EUV radiation can be emitted in silicon dioxide or sapphire. EUV light can also be emitted by free electrons orbiting a ...
Carefully drawn flawless glass fibres can be produced with strength of up to 11.5 gigapascals (1,670,000 psi). Silicon dioxide ... silicon dioxide, or quartz), the primary constituent of sand. Soda-lime glass, containing around 70% silica, accounts for ... Some of these glasses (e.g. Germanium dioxide (GeO2, Germania), in many respects a structural analogue of silica, fluoride, ...
... is mainly a mixture of metal oxides and silicon dioxide. Broadly, it can be classified as ferrous (by-products of ... Slag is usually a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and elemental metals. ... In some smelting processes, such as ilmenite smelting to produce titanium dioxide, the slag can be the valuable product. During ... During the process of smelting iron, ferrous slag is created, but dominated by calcium and silicon compositions. Through this ...
Silicon dioxide could be grown on a silicon semiconductor surface. Silicon oxide layers could protect silicon surfaces during ... HF is used to remove or pattern silicon dioxide in the semiconductor industry. Silicon dioxide acts as a Lux-Flood acid, being ... Silicon dioxide has been researched for agricultural applications as a potential insecticide. Silicon dioxide is mostly ... Colloidal silicon dioxide Dicalite DRI-DIE Insecticide 67 FLO-GARD Fossil flour Fumed silica Fumed silicon dioxide HI-SEL LO- ...
Pulsed KrF excimer laser dopant activation in nanocrystal silicon in a silicon dioxide matrix. ... Pulsed KrF excimer laser dopant activation in nanocrystal silicon in a silicon dioxide matrix, Applied Physics Letters ( ... www.nist.gov/publications/pulsed-krf-excimer-laser-dopant-activation-nanocrystal-silicon-silicon-dioxide-matrix ... used as a post-furnace annealing method to greatly increase the electrically active doping concentration in nanocrystal silicon ...
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It is a kind of fine silicon that can be uniformly dispersed. It is insoluble in water. Silicon is a natural element in the ... What is colloidal silicon dioxide?Colloidal silica is a gaseous silica prepared by hydrolysis of silica compounds. ... Is silicon dioxide good for your health?. Silicon dioxide naturally exists in the earth and in our bodies. There is no evidence ... The type of silicon dioxide added to foods, supplements and medicines is different from crystalline silicon dioxide. Inhaling ...
Low-k materials such as silicon dioxide (SiO2) play an important role in the semiconductor industry. Plasma has become ... Low-k materials such as silicon dioxide (SiO2) play an important role in the semiconductor industry. Plasma has become ... Raman scattering analysis of silicon dioxide single crystal treated by direct current plasma discharge D. M. Popovic; D. M. ... Low-k materials such as silicon dioxide (. SiO. 2. ). play an important role in the semiconductor industry. Plasma has become ...
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Variants of silicon dioxide. As the pressure increases up to 30 GPa, silicon dioxide continues to form with the tetrahedra ... Silicon dioxide, SiO2, also known as "quartz", is abundant both on the Earths surface and in its mantle. Linus Paulings ... Silicon dioxide with structures that are impossible according to traditional theories pressure is increased above 30 GPa using ... In these conditions, the researchers have found variants of silicon dioxide with structures that are impossible according to ...
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Silicon Dioxide (Si). 7602. SILICA, Respirable Crystalline, by IR (KBr pellet). Silicon Dioxide (Si). 7603. QUARTZ in ...
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Inorganic Silicon compounds. Silicon dioxide. 7631-86-9. 0.011385. 0.600000. 0.008640. Magnesium and its compounds. Talc. 14807 ... Inorganic Silicon compounds. Silicon dioxide. 7631-86-9. 11.104050. 15.000000. 8.426351. Inorganic compounds. Carbon Black. ... Inorganic Silicon compounds. Silicon dioxide. 7631-86-9. 0.050174. 1.200000. 0.038074. Miscellaneous substances. Other ... Inorganic Silicon compounds. Silicon dioxide. 7631-86-9. 0.085250. 1.700000. 0.064693. Miscellaneous substances. Other ...
Wang, N. F., Houng, M. P., & Wang, Y. H. (1999). Investigation of low-temperature deposition of silicon dioxide on indium ... Wang, NF, Houng, MP & Wang, YH 1999, Investigation of low-temperature deposition of silicon dioxide on indium phosphide by ... A new low-temperature process (35-45 °C) for the deposition of high-quality silicon dioxide (SiO2) films on indium phosphide ( ... abstract = "A new low-temperature process (35-45 °C) for the deposition of high-quality silicon dioxide (SiO2) films on indium ...
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4. Silicon dioxide thin films. Nowadays, the electronic industry is based on silicon dioxide technology. Since the 1980s, SiO2 ... Another dielectric candidate for replacing silicon dioxide in MOS devices is aluminium dioxide (alumina). It has excellent ... Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi- ... In the food industry, silicon dioxide is a common additive, used as a flow agent in powdered foods, or for water adsorption in ...
SILICON DIOXIDE (UNII: ETJ7Z6XBU4) METHYLPARABEN (UNII: A2I8C7HI9T) POLYOXYL 20 CETOSTEARYL ETHER (UNII: YRC528SWUY) ... TITANIUM DIOXIDE (UNII: 15FIX9V2JP) (TITANIUM DIOXIDE - UNII:15FIX9V2JP) TITANIUM DIOXIDE. 0.0468 g in 1 g. ... CYZONE SUN BY ME SUNBLOCK SPF 50- octinoxate, octocrylene, oxybenzone, octisalate, titanium dioxide, and ensulizole cream. If ... CYZONE SUN BY ME SUNBLOCK SPF 50- octinoxate, octocrylene, oxybenzone, octisalate, titanium dioxide, and ensulizole cream. ...
Foliar spray of silicon dioxide (SiO2 NPs), zinc oxide (ZnO NPs) and titanium dioxide (TiO2 NPs) nanoparticles were used for ... Effects of silicon dioxide, zinc oxide and titanium dioxide nanoparticles on Meloidogyne incognita, Alternaria dauci and ... Effects of silicon dioxide, zinc oxide and titanium dioxide nanoparticles on Meloidogyne i ...
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Silicon dioxideSilicon dioxide. CAS Number:. 7631-86-9. Molecular formula:. O2Si. IUPAC ... Silicon dioxideSilicon dioxide. CAS Number:. 7631-86-9. Molecular formula:. O2Si. IUPAC ... Germanium dioxidedioxide. CAS Number:. 1310-53-8. Molecular formula:. GeO2. ... Germanium dioxidedioxide. CAS Number:. 1310-53-8. Molecular formula:. GeO2. ...
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Concentration of disease-associated prion protein with silicon dioxide. Mol Biotechnol. 2009 Mar. 41(3):254-62. [QxMD MEDLINE ...
  • Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO2, commonly found in nature as quartz. (wikipedia.org)
  • Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. (wikipedia.org)
  • The dimeric silicon dioxide, (SiO2)2 has been obtained by reacting O2 with matrix isolated dimeric silicon monoxide, (Si2O2). (wikipedia.org)
  • We demonstrate that a pulsed KrF excimer laser (λ=248 nm, τ=22 ns) can be used as a post-furnace annealing method to greatly increase the electrically active doping concentration in nanocrystal silicon (ncSi) embedded in SiO2. (nist.gov)
  • Foliar spray of silicon dioxide (SiO2 NPs), zinc oxide (ZnO NPs) and titanium dioxide (TiO2 NPs) nanoparticles were used for the management of Meloidogyne incognita, Alternaria dauci and Rhizoctonia solani disease complex of carrot . (bvsalud.org)
  • Silica is another name for the chemical compound composed of silicon and oxygen with the chemical formula SiO2, or silicon dioxide. (cdc.gov)
  • c-Silica compounds have structures with repeating patterns of silicon and oxygen. (cdc.gov)
  • All forms of silica are odorless solids composed of silicon and oxygen atoms. (cdc.gov)
  • Based on the crystal structural differences, silicon dioxide can be divided into two categories: crystalline and non-crystalline (amorphous). (wikipedia.org)
  • The type of silicon dioxide added to foods, supplements and medicines is different from crystalline silicon dioxide. (hiphopgalaxy.com)
  • Effects of silicon dioxide, zinc oxide and titanium dioxide nanoparticles on Meloidogyne incognita, Alternaria dauci and Rhizoctonia solani disease complex of carrot. (bvsalud.org)
  • The starkly different structures of the dioxides of carbon and silicon are a manifestation of the double bond rule. (wikipedia.org)
  • Silicon dioxide with structures that are impossible according to traditional theories pressure is increased above 30 GPa using a diamond anvil, interesting things start to happen. (liu.se)
  • In these conditions, the researchers have found variants of silicon dioxide with structures that are impossible according to traditional theories of chemical bonding. (liu.se)
  • In the majority of silicon dioxides, the silicon atom shows tetrahedral coordination, with four oxygen atoms surrounding a central Si atom (see 3-D Unit Cell). (wikipedia.org)
  • It has been produced by combining silicon monoxide (SiO) with oxygen in an argon matrix. (wikipedia.org)
  • In dimeric silicon dioxide there are two oxygen atoms bridging between the silicon atoms with an Si-O-Si angle of 94° and bond length of 164.6 pm and the terminal Si-O bond length is 150.2 pm. (wikipedia.org)
  • Silicon dioxide, SiO 2 , also known as "quartz", is abundant both on the Earth's surface and in its mantle. (liu.se)
  • is an acidic oxide, corresponding to the hydrate is silicate (H 2 SiO 3 ).Silicon dioxide is one of the most complex and abundant families of materials, both mineral and synthetic.SiO 2 crystal has a variety of crystal types, and its basic structural unit is tetrahedron. (funcmater.com)
  • The low pressure chemical vapor deposition of silicon dioxide films in the temperature range 450 to 600C from a new source: Diacetoxydi-t-butoxysilane. (bell-labs.com)
  • A new low-temperature process (35-45 °C) for the deposition of high-quality silicon dioxide (SiO 2 ) films on indium phosphide (InP) by liquid phase deposition (LPD) is proposed. (ncku.edu.tw)
  • Wang, NF, Houng, MP & Wang, YH 1999, ' Investigation of low-temperature deposition of silicon dioxide on indium phosphide by liquid phase deposition ', Japanese Journal of Applied Physics , vol. 38, no. 10, pp. 6071-6072. (ncku.edu.tw)
  • They created a pattern of stripes on a water-loving hydrophilic silicon dioxide material. (asme.org)
  • In addition, the researchers found no association or association between silicon dioxide added to food and an increased risk of organ damage, disease or death. (hiphopgalaxy.com)
  • Silicon dioxide can also be found in baking mixes including flour. (ricehuskashindia.in)
  • As the pressure increases up to 30 GPa, silicon dioxide continues to form with the tetrahedra connected according to the traditional laws of chemistry. (liu.se)
  • LIBS is used to analyze the deposited material, determining the amount of silicon-containing compounds present. (cdc.gov)
  • A portable instrument has been developed for measuring silicon-containing aerosols in near real-time using laser-induced breakdown spectroscopy (LIBS). (cdc.gov)
  • The principal element of silicon dioxide nanoparticles is elemental silicon, known for its notable chemical stability and durability against high temperatures, strong acids, potent alkalis, and other harsh environments. (bluehost101.com)