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.
Solid dosage forms, of varying weight, size, and shape, which may be molded or compressed, and which contain a medicinal substance in pure or diluted form. (Dorland, 28th ed)
Drinkable liquids containing ETHANOL.
Spherical particles of nanometer dimensions.
Agreements between two or more parties, especially those that are written and enforceable by law (American Heritage Dictionary of the English Language, 4th ed). It is sometimes used to characterize the nature of the professional-patient relationship.
The collective name for the boron hydrides, which are analogous to the alkanes and silanes. Numerous boranes are known. Some have high calorific values and are used in high-energy fuels. (From Grant & Hackh's Chemical Dictionary, 5th ed)
Exclusive legal rights or privileges applied to inventions, plants, etc.
Fields of science encompassing studies and research from the disciplines of PHYSICS; CHEMISTRY; BIOLOGICAL SCIENCES; and MATHEMATICS; that are related to the planet EARTH. Subfields include atmospheric chemistry; CLIMATOLOGY; ENVIRONMENTAL SCIENCES; GEOGRAPHY; GEOLOGY; geophysics; METEOROLOGY; OCEANOGRAPHY; PALEONTOLOGY; mineralogy; and seismology.
The study of natural phenomena by observation, measurement, and experimentation.
The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Activity involved in transfer of goods from producer to consumer or in the exchange of services.
Detailed account or statement or formal record of data resulting from empirical inquiry.
A dark-gray, metallic element of widespread distribution but occurring in small amounts; atomic number, 22; atomic weight, 47.90; symbol, Ti; specific gravity, 4.5; used for fixation of fractures. (Dorland, 28th ed)
Time period from 1801 through 1900 of the common era.
Time period from 1901 through 2000 of the common era.
Electromagnetic waves with frequencies between about 3 kilohertz (very low frequency - VLF) and 300,000 megahertz (extremely high frequency - EHF). They are used in television and radio broadcasting, land and satellite communications systems, radionavigation, radiolocation, and DIATHERMY. The highest frequency radio waves are MICROWAVES.
Books used in the study of a subject that contain a systematic presentation of the principles and vocabulary of a subject.
Reduction of CEREBROSPINAL FLUID pressure characterized clinically by HEADACHE which is maximal in an upright posture and occasionally by an abducens nerve palsy (see ABDUCENS NERVE DISEASES), neck stiffness, hearing loss (see DEAFNESS); NAUSEA; and other symptoms. This condition may be spontaneous or secondary to SPINAL PUNCTURE; NEUROSURGICAL PROCEDURES; DEHYDRATION; UREMIA; trauma (see also CRANIOCEREBRAL TRAUMA); and other processes. Chronic hypotension may be associated with subdural hematomas (see HEMATOMA, SUBDURAL) or hygromas. (From Semin Neurol 1996 Mar;16(1):5-10; Adams et al., Principles of Neurology, 6th ed, pp637-8)
Compounds similar to hydrocarbons in which a tetravalent silicon atom replaces the carbon atom. They are very reactive, ignite in air, and form useful derivatives.