text stringlengths 107 11k | label int64 0 1 | label_text stringclasses 2
values |
|---|---|---|
Litmus can be found in different species of lichens. The dyes are extracted from such species as Roccella tinctoria (South American), Roccella fuciformis (Angola and Madagascar), Roccella pygmaea (Algeria), Roccella phycopsis, Lecanora tartarea (Norway, Sweden), Variolaria dealbata, Ochrolechia parella, Parmotrema tinc... | 0 | Chromatography + Titration + pH indicators |
Chromatography is a physical method of separation that distributes the components you want to separate between two phases, one stationary (stationary phase), the other (the mobile phase) moving in a definite direction. Cold ethanol precipitation, developed by Cohn in 1946, manipulates pH, ionic strength, ethanol concen... | 0 | Chromatography + Titration + pH indicators |
Several GC–MS systems have left earth. Two were brought to Mars by the Viking program. Venera 11 and 12 and Pioneer Venus analysed the atmosphere of Venus with GC–MS. The Huygens probe of the Cassini–Huygens mission landed one GC–MS on Saturns largest moon, Titan. The MSL Curiosity rovers Sample analysis at Mars (SAM) ... | 0 | Chromatography + Titration + pH indicators |
Shodex is the brand name of HPLC columns and is best known for polymer-based columns. The product range covers aqueous and organic Size Exclusion Chromatography columns for large (bio-)molecules, columns for the routine analysis of sugars and organic acids, and a variety of Reversed Phase and HILIC columns. Additionall... | 0 | Chromatography + Titration + pH indicators |
Microcrystallization (or microcrystal test) is a method for identifying lichen metabolites that was predominantly used before the advent of more advanced techniques such as thin-layer chromatography and high-performance liquid chromatography. Developed primarily by Yasuhiko Asahina, this approach relies on the formatio... | 1 | Crystallography |
The concept of using a post-column catalytic reactor to enhance the response of the FID was described by Kenneth Porter & D.H. Volman, for the reduction of carbon dioxide and carbon monoxide to methane using a nickel catalyst. This process was later refined by Johns & Thompson, and is now commonplace in many laboratori... | 0 | Chromatography + Titration + pH indicators |
Instrumentation of supercritical fluid chromatography SFC has a similar setup to an HPLC instrument. The stationary phases are similar, and are packed inside similar column types. However, there are special features in these systems, because of the need to keep the mobile phase at supercritical fluidic state over the e... | 0 | Chromatography + Titration + pH indicators |
Selective enzyme and antibody separation can be achieved with the use of specific end groups that conjugate with the specific compounds. This results in a formation of a polymer-enzyme conjugate which can be reversibly precipitated and dissolved by changing the temperature. Chen and Hoffman used N-Hydroxysuccinimide (N... | 0 | Chromatography + Titration + pH indicators |
* Liquid chromatography: Traditional chromatography columns were made of glass. Modern columns are mostly made of borosilicate glass, acrylic glass or stainless steel. To prevent the stationary phase from leaking out of the column interior a polymer, stainless steel or ceramic net is usually applied. Depending on the ... | 0 | Chromatography + Titration + pH indicators |
Simple:
* Strontium titanate
* Calcium titanate
* Lead titanate
* Bismuth ferrite
* Lanthanum ytterbium oxide
* Silicate perovskite
* Lanthanum manganite
* Yttrium aluminum perovskite (YAP)
* Lutetium aluminum perovskite (LuAP)
Solid solutions:
* Lanthanum strontium manganite
* LSAT (lanthanum aluminate – strontium alu... | 1 | Crystallography |
Malachite green is traditionally used as a dye. Kilotonnes of MG and related triarylmethane dyes are produced annually for this purpose.
MG is active against the oomycete Saprolegnia, which infects fish eggs in commercial aquaculture, MG has been used to treat Saprolegnia and is used as an antibacterial. It is a very p... | 0 | Chromatography + Titration + pH indicators |
α-Naphtholphthalein (CHO) is a phthalein dye used as a pH indicator with a visual transition from colorless/reddish to greenish blue at pH 7.3–8.7. | 0 | Chromatography + Titration + pH indicators |
In one version of the laser spray interface, explosive vaporization and mist formation occur when an aqueous solution effusing from the tip of the stainless steel capillary is irradiated from the opposite side of the capillary by a 10.6 μm infrared laser. Weak ion signals could be detected when the plume was sampled th... | 0 | Chromatography + Titration + pH indicators |
In 2007 Houser et al. developed the analogous parameter to distinguish whether the geometry of the coordination center is square planar or tetrahedral. The formula is:
where: and are the two greatest valence angles of coordination center; is a tetrahedral angle.
When is close to 0 the geometry is similar to square... | 1 | Crystallography |
Suppose that a plane wave (of any type) is incident on planes of lattice points, with separation , at an angle as shown in the Figure. Points A and C are on one plane, and B is on the plane below. Points ABCC' form a quadrilateral.
There will be a path difference between the ray that gets reflected along AC' and the... | 1 | Crystallography |
Native chemical ligation of unprotected peptide segments is used to prepare the protein's polypeptide chain, which is then folded to form a protein molecule. In native chemical ligation, a peptide C-terminal thioester reacts with a second peptide that has a cysteine residue at its N-terminus, to give a product with a p... | 1 | Crystallography |
HPTLC comprises three modes: linear mode, circular mode, and anticircular mode. Among these modes, the anticircular mode stands out as the fastest in theory and practice within the realm of HPTLC. This mode achieves separation by allowing the mobile phase to enter the plate layer precisely along an outer circular path,... | 0 | Chromatography + Titration + pH indicators |
The screw axis appears in the dual quaternion formulation of a spatial displacement . The dual quaternion is constructed from the dual vector defining the screw axis and the dual angle , where φ is the rotation about and d the slide along this axis, which defines the displacement D to obtain,
A spatial displacement of... | 1 | Crystallography |
In analytical and organic chemistry, elution is the process of extracting one material from another by washing with a solvent: washing of loaded ion-exchange resins to remove captured ions, or eluting proteins or other biopolymers from a gel electrophoresis or chromatography column.
In a liquid chromatography experimen... | 0 | Chromatography + Titration + pH indicators |
Bromothymol blue acts as a weak acid in a solution. It can thus be in protonated or deprotonated form, appearing yellow or blue, respectively. It is bright aquamarine by itself, and greenish-blue in a neutral solution. The deprotonation of the neutral form results in a highly conjugated structure, accounting for the di... | 0 | Chromatography + Titration + pH indicators |
A sample is introduced, either manually or with an autosampler, into a sample loop of known volume. A buffered aqueous solution known as the mobile phase carries the sample from the loop onto a column that contains some form of stationary phase material. This is typically a resin or gel matrix consisting of agarose or... | 0 | Chromatography + Titration + pH indicators |
Sunset yellow FCF (also known as orange yellow S, or C.I. 15985) is a petroleum-derived orange azo dye with a pH dependent maximum absorption at about 480 nm at pH 1 and 443 nm at pH 13 with a shoulder at 500 nm. When added to foods sold in the United States it is known as FD&C Yellow 6; when sold in Europe, it is den... | 0 | Chromatography + Titration + pH indicators |
The roots of liquid chromatography extend back over a century ago to 1900, when Russian botanist Mikhail Tsvet began experimenting with plant pigments in chlorophyll. He noted that, when a solvent was applied, distinct bands appeared that migrated at different rates along a stationary phase. For this new observation, h... | 0 | Chromatography + Titration + pH indicators |
Crystal parting occurs when minerals break along planes of structural weakness due to external stress, along twin composition planes, or along planes of weakness due to the exsolution of another mineral. Parting breaks are very similar in appearance to cleavage, but the cause is different. Cleavage occurs because of de... | 1 | Crystallography |
Although malachite green has almost no fluorescence in aqueous solution (quantum yield 7.9x10), several research groups have developed technologies to detect malachite green. For example, Zhao et al., demonstrated the use of malachite green aptamer in microcantilever based sensors to detect low concentration of malachi... | 0 | Chromatography + Titration + pH indicators |
Mixtures of complex acids can be resolved by thermometric titration with standard NaOH in aqueous solution. In a mixture of nitric, acetic and phosphoric acids used in the fabrication of semi-conductors, three endpoints could be predicted on the basis of the dissociation constants of the acids:
The key to determine the... | 0 | Chromatography + Titration + pH indicators |
Retention uniformity is calculated from the following formula:
where n is the number of compounds separated, R are the Retention factor of the compounds sorted in non-descending order. | 0 | Chromatography + Titration + pH indicators |
Translations, denoted by T, where v is a vector in R have the effect of shifting the plane in the direction of v. That is, for any point p in the plane,
:or in terms of (x, y) coordinates,
A translation can be seen as a composite of two parallel reflections. | 1 | Crystallography |
Rigid unit modes (RUMs) represent a class of lattice vibrations or phonons that exist in network materials such as quartz, cristobalite or zirconium tungstate. Network materials can be described as three-dimensional networks of polyhedral groups of atoms such as SiO tetrahedra or TiO octahedra. A RUM is a lattice vibra... | 1 | Crystallography |
D designates compounds of arbitrary stoichiometry. Originally, D1-D10 were set aside for stoichiometry AB, D11-D20 for stoichiometry AB for n > 3, D31-D50 for (AB), and D51 up for the AB for arbitrary m and n. | 1 | Crystallography |
The advent of displacement chromatography can be attributed to Arne Tiselius, who in 1943 first classified the modes of chromatography as frontal, elution, and displacement. Displacement chromatography found a variety of applications including isolation of transuranic elements and biochemical entities.
The technique wa... | 0 | Chromatography + Titration + pH indicators |
In a crystal, the constitutive particles are arranged periodically, with translational symmetry forming a lattice. The crystal structure can be described as a Bravais lattice with a group of atoms, called the basis, placed at every lattice point; that is, [crystal structure] = [lattice] [basis]. If the lattice is infi... | 1 | Crystallography |
Bragg diffraction (also referred to as the Bragg formulation of X-ray diffraction) was first proposed by Lawrence Bragg and his father, William Henry Bragg, in 1913 after their discovery that crystalline solids produced surprising patterns of reflected X-rays (in contrast to those produced with, for instance, a liquid)... | 1 | Crystallography |
Friedels salt plays a main role in the binding and retention of chloride anions in cement and concrete. However, Friedels salt remains a poorly understood phase in the CaO–AlO–CaCl–HO system. A sufficient understanding of the Friedel's salt system is essential to correctly model the reactive transport of chloride ions... | 1 | Crystallography |
A uniform structure is identified by each sphere having the same number of contacting neighbours. This gives each sphere an identical neighbourhood. In the example image on the side each sphere has six neighbouring contacts.
The number of contacts is best visualised in the rolled-out contact network. It is created by r... | 1 | Crystallography |
When an excess of Ba is added to a non-ionic surfactant of the alkyl propylene oxide derivative type, a pseudo-cationic complex is formed. This may be titrated with standard sodium tetraphenylborate. Two moles tetraphenylborate react with one mole of the Ba/ non-ionic surfactant complex. | 0 | Chromatography + Titration + pH indicators |
When a crystal is composed of crystallites with varying lattice orientation, topographic contrast arises: In plane-wave topography, only selected crystallites will be in diffracting position, thus yielding diffracted intensity only in some parts of the image. Upon sample rotation, these will disappear, and other crysta... | 1 | Crystallography |
Two-dimensional chromatography represents the most thorough and rigorous approach to evaluation of the proteome. While previously accepted approaches have utilized elution mode chromatographic approaches such as cation exchange to reversed phase HPLC, yields are typically very low requiring analytical sensitivities in ... | 0 | Chromatography + Titration + pH indicators |
If the crystal diffracts to high resolution (<1.2 Å), the initial phases can be estimated using direct methods. Direct methods can be used in x-ray crystallography, neutron crystallography, and electron crystallography.
A number of initial phases are tested and selected by this method. The other is the Patterson meth... | 1 | Crystallography |
Sunset yellow FCF is known as FD&C yellow No. 6 in the US and is approved for use in coloring food, drugs, and cosmetics with an acceptable daily intake of 3.75 mg/kg. | 0 | Chromatography + Titration + pH indicators |
Anthocyanins fluoresce, enabling a tool for plant cell research to allow live cell imaging without a requirement for other fluorophores. Anthocyanin production may be engineered into genetically modified materials to enable their identification visually. | 0 | Chromatography + Titration + pH indicators |
This parameter is often used in biomechanics, when describing the motion of joints of the body. For any period of time, joint motion can be seen as the movement of a single point on one articulating surface with respect to the adjacent surface (usually distal with respect to proximal). The total translation and rotatio... | 1 | Crystallography |
In crystallography, the R-factor (sometimes called residual factor or reliability factor or the R-value or R) is a measure of the agreement between the crystallographic model and the experimental X-ray diffraction data. In other words, it is a measure of how well the refined structure predicts the observed data. The va... | 1 | Crystallography |
Combinations of chromatographic methods can be used to purify a target molecule. The purpose of purifying proteins with FPLC is to deliver quantities of the target at sufficient purity in a biologically active state to suit its further use. The quality of the end product varies depending the type and amount of starting... | 0 | Chromatography + Titration + pH indicators |
Columnar structures have also been studied intensively in the context of nanotubes. Their physical or chemical properties can be altered by trapping identical particles inside them. These are usually done by self-assembling fullerenes such as C60, C70, or C78 into carbon nanotubes, but also boron nitride nanotubes
Such... | 1 | Crystallography |
A simple cubic unit cell, with stacks of atoms arranged as if at the eight corners of a cube would form a single cubic hole or void in the center. If these voids are occupied by ions of opposite charge from the parent lattice, the cesium chloride structure is formed. | 1 | Crystallography |
Drugs receive regulatory approval and are granted patents for only a single polymorph.
In a classic patent dispute, the GlaxoSmithKline defended its patent for the Type II polymorph of the active ingredient in Zantac against competitors while that of the Type I polymorph had already expired.
Polymorphism in drugs can ... | 1 | Crystallography |
Acid–base titrations depend on the neutralization between an acid and a base when mixed in solution. In addition to the sample, an appropriate pH indicator is added to the titration chamber, representing the pH range of the equivalence point. The acid–base indicator indicates the endpoint of the titration by changing ... | 0 | Chromatography + Titration + pH indicators |
A mass spectrometer is typically utilized in one of two ways: full scan or selective ion monitoring (SIM). The typical GC–MS instrument is capable of performing both functions either individually or concomitantly, depending on the setup of the particular instrument.
The primary goal of instrument analysis is to quanti... | 0 | Chromatography + Titration + pH indicators |
The Macromolecular Crystallographic Information File (mmCIF) also known as PDBx/mmCIF is a standard text file format for representing macromolecular structure data, developed by the International Union of Crystallography (IUCr) and the Protein Data Bank It is an extension of the Crystallographic Information File (CIF),... | 1 | Crystallography |
QR has many uses as a fluorescent probe. The use of QR as a probe is relatively safe, inexpensive, and a sensitive method compared with other fluorescence probes like ethidium bromide or dimeric cyanine dyes. QR is also an ideal fluorescent probe because substrates of interest, such as antibodies, can be detected withi... | 0 | Chromatography + Titration + pH indicators |
Modern two-dimensional chromatographic techniques are based on the results of the early developments of paper chromatography and thin-layer chromatography (TLC) which involved liquid mobile phases and solid stationary phases. These techniques would later generate modern gas chromatography (GC) and liquid chromatography... | 0 | Chromatography + Titration + pH indicators |
In materials science, Ostwalds rule or Ostwalds step rule, conceived by Wilhelm Ostwald, describes the formation of polymorphs. The rule states that usually the less stable polymorph crystallizes first. Ostwald's rule is not a universal law but a common tendency observed in nature.
This can be explained on the basis of... | 1 | Crystallography |
Le Bail analysis is a whole diffraction pattern profile fitting technique used to characterize the properties of crystalline materials, such as structure. It was invented by Armel Le Bail around 1988. | 1 | Crystallography |
We thus have two new kinds of isometry subgroups: all translations, and rotations sharing a fixed point. Both are subgroups of the even subgroup, within which translations are normal. Because translations are a normal subgroup, we can factor them out leaving the subgroup of isometries with a fixed point, the orthogonal... | 1 | Crystallography |
A transversely isotropic material is one with physical properties that are symmetric about an axis that is normal to a plane of isotropy. This transverse plane has infinite planes of symmetry and thus, within this plane, the material properties are the same in all directions. Hence, such materials are also known as "po... | 1 | Crystallography |
4-nitro phenol is a slightly yellow, crystalline material, moderately toxic.
It shows two polymorphs in the crystalline state. The alpha-form is colorless pillars, unstable at room temperature, and stable toward sunlight. The beta-form is yellow pillars, stable at room temperature, and gradually turns red upon irradi... | 0 | Chromatography + Titration + pH indicators |
The dynamically, or inelastically, scattered electrons provide several types of information about the sample as well. The brightness or intensity at a point on the detector depends on dynamic scattering, so all analysis involving the intensity must account for dynamic scattering. Some inelastically scattered electrons ... | 1 | Crystallography |
In the 1940s Craig invented the first apparatus to conduct countercurrent partitioning; he called this the countercurrent distribution Craig apparatus. The apparatus consists of a series of glass tubes that are designed and arranged such that the lighter liquid phase is transferred from one tube to the next. The next m... | 0 | Chromatography + Titration + pH indicators |
The instantaneous motion of a rigid body may be the combination of rotation about an axis (the screw axis) and a translation along that axis. This screw move is characterized by the velocity vector for the translation and the angular velocity vector in the same or opposite direction. If these two vectors are constant a... | 1 | Crystallography |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.