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Dark Quencher
A dark quencher (also known as a dark sucker) is a substance that absorbs excitation energy from a fluorophore and dissipates the energy as ''heat''; while a typical (fluorescent) quencher re-emits much of this energy as ''light''. Dark quenchers are used in molecular biology in conjunction with fluorophores. When the two are close together, such as in a molecule or protein, the fluorophore's emission is suppressed. This effect can be used to study molecular geometry and motion. An example of its use is in TaqMan or invader assay, SNP genotyping methods. For instance, a hairpin loop with a fluorophore and quencher at the base of the stem is used. An unlabeled SNP specific PCR primer (one of many) with a specific 5' tail binds to the sequence to be probed, and the Taq polymerase extends the sequence that will have a specific 5' end dependent on the SNP (insensitive to polymorphisms upstream of the SNP in question). In the next run, a primer, complementary to that tail, with a hairp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorophore
A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with several π bonds. Fluorophores are sometimes used alone, as a tracer in fluids, as a dye for staining of certain structures, as a substrate of enzymes, or as a probe or indicator (when its fluorescence is affected by environmental aspects such as polarity or ions). More generally they are covalently bonded to a macromolecule, serving as a marker (or dye, or tag, or reporter) for affine or bioactive reagents (antibodies, peptides, nucleic acids). Fluorophores are notably used to stain tissues, cells, or materials in a variety of analytical methods, i.e., fluorescent imaging and spectroscopy. Fluorescein, via its amine-reactive isothiocyanate derivative fluorescein isothiocyanate (FITC), has been one of the most popular fluorophores. Fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground State
The ground state of a quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state. In quantum field theory, the ground state is usually called the vacuum state or the vacuum. If more than one ground state exists, they are said to be degenerate. Many systems have degenerate ground states. Degeneracy occurs whenever there exists a unitary operator that acts non-trivially on a ground state and commutes with the Hamiltonian of the system. According to the third law of thermodynamics, a system at absolute zero temperature exists in its ground state; thus, its entropy is determined by the degeneracy of the ground state. Many systems, such as a perfect crystal lattice, have a unique ground state and therefore have zero entropy at absolute zero. It is also possible for the highest excited state to have absolute zero temper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iowa Black RQ
Iowa () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the east and southeast, Missouri to the south, Nebraska to the west, South Dakota to the northwest, and Minnesota to the north. During the 18th and early 19th centuries, Iowa was a part of Louisiana (New France), French Louisiana and Louisiana (New Spain), Spanish Louisiana; its Flag of Iowa, state flag is patterned after the flag of France. After the Louisiana Purchase, people laid the foundation for an agriculture-based economy in the heart of the Corn Belt. In the latter half of the 20th century, Iowa's agricultural economy transitioned to a diversified economy of advanced manufacturing, processing, financial services, information technology, biotechnology, and Sustainable energy, green energy productio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iowa Black FQ
Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the east and southeast, Missouri to the south, Nebraska to the west, South Dakota to the northwest, and Minnesota to the north. During the 18th and early 19th centuries, Iowa was a part of French Louisiana and Spanish Louisiana; its state flag is patterned after the flag of France. After the Louisiana Purchase, people laid the foundation for an agriculture-based economy in the heart of the Corn Belt. In the latter half of the 20th century, Iowa's agricultural economy transitioned to a diversified economy of advanced manufacturing, processing, financial services, information technology, biotechnology, and green energy production. Iowa is the 26th most extensive in total area and the 31st most populous of the 50 U.S. states, with a populati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Hole Quenchers
Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have often been used to describe opposites such as good and evil, the Dark Ages versus Age of Enlightenment, and night versus day. Since the Middle Ages, black has been the symbolic color of solemnity and authority, and for this reason it is still commonly worn by judges and magistrates. Black was one of the first colors used by artists in Neolithic cave paintings. It was used in ancient Egypt and Greece as the color of the underworld. In the Roman Empire, it became the color of mourning, and over the centuries it was frequently associated with death, evil, witches, and magic. In the 14th century, it was worn by royalty, clergy, judges, and government officials in much of Europe. It became the color worn by English romantic poets, businessmen an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfonyl Chloride
In inorganic chemistry, sulfonyl halide groups occur when a sulfonyl () functional group is singly bonded to a halogen atom. They have the general formula , where X is a halogen. The stability of sulfonyl halides decreases in the order fluorides > chlorides > bromides > iodides, all four types being well known. The sulfonyl chlorides and fluorides are of dominant importance in this series. Structure Sulfonyl halides have tetrahedral sulfur centres attached to two oxygen atoms, an organic radical, and a halide. In a representative example, methanesulfonyl chloride, the S=O, S−C, and S−Cl bond distances are respectively 142.4, 176.3, and 204.6 pm. Sulfonyl chlorides Sulfonic acid chlorides, or sulfonyl chlorides, are a sulfonyl halide with the general formula . Production Arylsulfonyl chlorides are made industrially in a two-step, one-pot reaction from an arene (in this case, benzene) and chlorosulfuric acid: :C6H6 + HOSO2Cl -> C6H5SO3H + HCl :C6H5SO3H + HOSO2Cl -> C6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after. Fluorescence has many practical applications, including mineralogy, gemology, medicine, chemical sensors (fluorescence spectroscopy), fluorescent labelling, dyes, biological detectors, cosmic-ray detection, vacu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quenching (fluorescence)
Quenching refers to any process which decreases the fluorescence intensity of a given substance. A variety of processes can result in quenching, such as excited state reactions, energy transfer, complex-formation and collisional quenching. As a consequence, quenching is often heavily dependent on pressure and temperature. Molecular oxygen, iodide ions and acrylamide are common chemical quenchers. The chloride ion is a well known quencher for quinine fluorescence. Quenching poses a problem for non-instant spectroscopic methods, such as laser-induced fluorescence. Quenching is made use of in optode sensors; for instance the quenching effect of oxygen on certain ruthenium complexes allows the measurement of oxygen saturation in solution. Quenching is the basis for Förster resonance energy transfer (FRET) assays. Quenching and dequenching upon interaction with a specific molecular biological target is the basis for activatable optical contrast agents for molecular imaging. Many dyes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Förster Resonance Energy Transfer
Förster resonance energy transfer (FRET), fluorescence resonance energy transfer, resonance energy transfer (RET) or electronic energy transfer (EET) is a mechanism describing energy transfer between two light-sensitive molecules ( chromophores). A donor chromophore, initially in its electronic excited state, may transfer energy to an acceptor chromophore through nonradiative dipole–dipole coupling. The efficiency of this energy transfer is inversely proportional to the sixth power of the distance between donor and acceptor, making FRET extremely sensitive to small changes in distance. Measurements of FRET efficiency can be used to determine if two fluorophores are within a certain distance of each other. Such measurements are used as a research tool in fields including biology and chemistry. FRET is analogous to near-field communication, in that the radius of interaction is much smaller than the wavelength of light emitted. In the near-field region, the excited chromophore e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primer (molecular Biology)
Primer may refer to: Arts, entertainment, and media Films * ''Primer'' (film), a 2004 feature film written and directed by Shane Carruth * ''Primer'' (video), a documentary about the funk band Living Colour Literature * Primer (textbook), a textbook used in primary education to teach the alphabet and other basic subjects * Primer (prayer book), a common name for English prayer books used from the 13th to 16th centuries * ''The New England Primer'' (1688), a Puritan book from Colonial America with morality-themed rhymes Music * ''Primer'' (album), a 1995 music album by the musical group Rockapella * Primer 55, an American alternative metal band * "The Primer", a song from the 2005 album ''Alaska'' by Between the Buried and Me Firearms * Primer (firearms), a firearm powder charge-ignition mechanism ** Centerfire ammunition, Boxer or Berdan primers used in modern centerfire cartridges ** Detonator, a small explosive device also known as an explosive primer or blasting cap ** Fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
