Refimprove date July 2008 Image Spektrofotometri.jpg thumb 300px Spectrophotometer In chemistry , spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. ref Allen, D., Cooksey, C., & Tsai, B. 2010, October 5 . Spectrophotometry. Retrieved from http www.nist.gov pml div685 grp03 spectrophotometry.cfm ref It is more specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with Visible spectrum visible light, near ultraviolet , and near infrared , but does not cover time resolved spectroscopy time resolved spectroscopic techniques. Spectrophotometry involves the use of a spectrophotometer. A spectrophotometer is a photometer a device for measuring light intensity that can measure intensity as a function of the light source wavelength. Important features of spectrophotometers are spectral bandwidth and linear range of absorption or reflectance measurement. A spectrophotometer is commonly used for the measurement of transmittance or reflectance of solutions, transparent or opaque solids, such as polished glass, or gases. However they can also be designed to measure the diffusivity ... and calibrations . ref Allen, D., Cooksey, C., & Tsai, B. 2010, October 5 . Spectrophotometry ... 17 ref An example of an experiment in which spectrophotometry is used is the determination of the equilibrium ... of the solution can be tested using spectrophotometry. The amount of light that passes through ... relative to the initial substance . ref name george UV visible spectrophotometry main Ultraviolet ... as well. Visible region 400 700 nm spectrophotometry is used extensively in colorimetry science ... , plastic , or quartz glass quartz . IR spectrophotometry main Infrared spectroscopy Spectrophotometers .... Samples for IR spectrophotometry may be smeared between two discs of potassium bromide or ground ... Spectrophotometry Atomic emission spectroscopy Inductively coupled plasma atomic emission spectroscopy ... more details
Photometry can refer to Photometry optics , the science of measurement of visible light in terms of its perceived brightness to human vision Photometry astronomy , the measurement of the flux or intensity of an astronomical object s electromagnetic radiation Spectrophotometry , the measurement of spectral distribution along with the flux or intensity A photometric study , sometimes also referred to as a lighting layout or point by point Photometric stereo , a computer vision technique also known as shape from shading See also Radiometry disambig es Fotometr a desambiguaci n fr Photom trie sr ... more details
orphan date August 2010 infobox tool name GeneQuant image Genequant.jpg image size caption other name classification types used with inventor manufacturer model related GeneQuant is a Electronic test equipment tool that can be used to measure the concentration of nucleic acid and protein from a sample. The basic principle of this tool is to measure the absorbance of the sample at 230, 260, 280, 320, 546, 562, 595 and 600 nm, so it works like a Spectrophotometry spectrophotometer . Category Laboratory equipment biology stub id GeneQuant ... more details
A fluorometer or fluorimeter is a device used to measure parameters of fluorescence its intensity and wavelength distribution of emission spectrum after Excitation spectrum excitation by a certain spectrum of light. ref http www.scribd.com doc 10514060 Fluorescence Spectrophotometry ref These parameters are used to identify the presence and the amount of specific molecules in a medium. Modern fluorometers are capable of detecting fluorescent molecule concentrations as low as 1 part per trillion. Fluorescence analysis can be orders of magnitude more sensitive than other techniques. Applications include chemistry biochemistry , medicine , Environmental quality environmental monitoring. For instance, they are used to measure chlorophyll fluorescence to investigate plant physiology. Fluorometer types Filter fluorometer Spectrofluorometer See also Fluorescence spectroscopy , for a fuller discussion of instrumentation Chlorophyll fluorescence , to investigate plant ecophysiology. Radiometer , to measure various electromagnetic radiation Spectrometer , to analyze spectrum of electromagnetic radiation Scatterometer , to measure scattered radiation Category Laboratory equipment Category Electromagnetic radiation meters es Fluor metro it Fluorimetro nl Fluorimeter sv Fluorimeter Reflist http www.scribd.com doc 10514060 Fluorescence Spectrophotometry ... more details
Spectrometry may refer to Ion mobility spectrometry , an analytical technique used to separate and identify ionized molecules in the gas phase based on their ion mobility in a carrier buffer gas Mass spectrometry , an analytical technique that measures the mass to charge ratio of charged particles Rutherford backscattering spectrometry , an analytical technique used to determine the structure and composition of materials by measuring the back scattering of a beam of high energy ions impinging on a sample Neutron triple axis spectrometry , a technique used in inelastic neutron scattering Spectroscopy Optical spectrometry , a technique for measuring the distribution of light across the optical spectrum, from the Ultraviolet UV spectral region to the Visible spectrum visible and Infrared spectroscopy infrared . See also Spectrometer Spectrophotometry Spectroscopy disambig ca Espectrometria ... more details
, a mathematical structure often written as Spec R Spectrophotometry , a science of measuring light intensity and wavelength Spectrophotometer, an instrument used in spectrophotometry GNU Compiler ... more details
chembox verifiedrevid 400116938 ImageFile Indophenol.svg ImageSize IUPACName 4 4 hydroxyphenyl iminocyclohexa 2,5 dien 1 one OtherNames Section1 Chembox Identifiers ChemSpiderID Ref chemspidercite correct chemspider ChemSpiderID 9951 InChI 1 C12H9NO2 c14 11 5 1 9 2 6 11 13 10 3 7 12 15 8 4 10 h1 8,14H InChIKey RSAZYXZUJROYKR UHFFFAOYAS StdInChI Ref stdinchicite correct chemspider StdInChI 1S C12H9NO2 c14 11 5 1 9 2 6 11 13 10 3 7 12 15 8 4 10 h1 8,14H StdInChIKey Ref stdinchicite correct chemspider StdInChIKey RSAZYXZUJROYKR UHFFFAOYSA N CASNo 500 85 6 PubChem 10379 SMILES O C 2 C C C N c1ccc O cc1 C C 2 Section2 Chembox Properties C 12 H 9 N 1 O 2 Appearance Density MeltingPt BoilingPt Solubility Section3 Chembox Hazards MainHazards FlashPt Autoignition Indophenol is an artificial blue metachromatic dye , obtained by the action of Phenols phenol on certain nitrogenous derivatives of quinone . ref http dictionary.reference.com browse indophenol Definition of indophenol from Dictionary.com ref Indophenol resembles the color indigo in appearance. Dichlorphenolindophenol Dichlorophenol indophenol DCPIP , a form of indophenol, is often used to determine the presence of vitamin C , or ascorbic acid . ref http www3.interscience.wiley.com journal 113291042 abstract?CRETRY 1&SRETRY 0 Ascorbic acid and indophenol ref The formation of indophenol is used to determine ammonia and paracetamol by spectrophotometry. ref Tsuboi, T. Hirano, Y. Shibata, Y. Motomizu, S. Sensitivity Improvement of Ammonia Determination Based on Flow Injection Indophenol Spectrophotometry with Manganese II Ion as a Catalyst and Analysis of Exhaust Gas of Thermal Power Plant, Analytical Sciences, October 2002, Vol. 18, pp. 1141 4 ref Indophenol blue CAS 132 31 0 is a completely different molecule with systematic name N p dimethylaminophenyl 1,4 naphthoquinoneimine . ref http www.sciencemag.org cgi content abstract 139 3557 835 Systematic name of idophenol blue ref References references Category Indopheno ... more details
Unreferenced date December 2009 Image chlorophyll ab spectra.png thumb Absorbance spectra of free chlorophyll a span style color green green span and b span style color red red span in a solvent. The action spectra of chlorophyll molecules are slightly modified in vivo depending on specific pigment protein interactions. An action spectrum is the rate of a physiological activity plotted against wavelength of light . It shows which wavelength of light is most effectively used in a specific chemical reaction . Some reactant s are able to use specific wavelengths of light more effectively to complete their reactions. For example, chlorophyll is much more efficient at using the red and blue spectrum s of light to carry out photosynthesis . Therefore, the action spectrum graph would show spikes above the wavelengths representing the colors red and blue . See also Photosynthesis Absorption spectrum Chlorophyll a External links http 5e.plantphys.net article.php?ch 7&id 66 Plant Physiology Online Principles of Spectrophotometry DEFAULTSORT Abrsorption Spectrum Category Photosynthesis Biochem stub ... more details
to form visible colonies. Spectrophotometry Image Spektrofotometri.jpg thumb 200px right A spectrophotometer ... through. The higher the cell concentration is, the higher the turbidity. Spectrophotometry Spectrophotometer ... spectrophotometry for measuring the turbidity of cultures is known as turbidometry . In spectrophotometry ... is the cheapest and its operation the fastest and most straightforward. This has made spectrophotometry .... Spectrophotometry s drawback is its limited accuracy it is the only method in which the cells are not counted ... more details
Unreferenced date December 2009 In chemistry , the path length is defined as the distance that light UV Visible spectrum VIS travels through a sample in an analytical cell. Typically, a sample cell is made of quartz , glass, or a plastic rhombic cuvette with a volume typically ranging from 0.1 mL to 10 mL or larger used in a spectrophotometer . For the purposes of spectrophotometry i.e. when making calculations using the Beer Lambert law the path length is measured in centimeters rather than in meters . In a computer network , the path length is one of many possible router metrics used by a router computing router to help determine the best Routing route among multiple routes to a destination. It consists of the end to end hop count from a source to a destination over the network. More simply, in general computer terminology, it can mean simply the total number of instructions executed from point A to point B in a program Instruction path length . In physics, the path length is defined as the total distance an object travels. Unlike displacement, which is the total distance an object travels from a starting point, path length is the total distance travelled, regardless of where it travelled. DEFAULTSORT Path Length Category Spectroscopy Category Computer networking Category Computing terminology ... more details
The Liebermann Burchard or acetic anhydride test is used for the detection of cholesterol . The formation of a green or green blue colour after a few minutes is positive. Lieberman Burchard is a reagent used in a colourimetric test to detect cholesterol, which gives a deep green colour. This colour begins as a purplish, pink colour and progresses through to a light green then very dark green colour. The colour is due to the hydroxyl group OH of cholesterol reacting with the reagents and increasing the conjugation of the un saturation in the adjacent fused ring. Since this test uses acetic anhydride and sulfuric acid as reagent s, caution must be exercised so as not to receive severe burns. Method Dissolve one or two crystals of cholesterol in dry chloroform in a dry test tube. Add several drops of acetic anhydride and then 2 drops of conc.H sub 2 sub SO sub 4 sub and mix carefully. After the reaction finished, the concentration of cholesterol can be measured using spectrophotometry . References Campbell, Mary K. & Shawn O. Farrell. Biochemistry. 4th ed. . Singapore Thomson Asia Pte Ltd. 2005 . http www.clinchem.org cgi reprint 20 7 794.pdf Category Medical tests Category Article Feedback 5 Med diagnostic stub de Liebermann Burchard Reaktion ... more details
A photoelectric flame photometer is a device used in Inorganic chemistry inorganic chemical Analytical chemistry analysis to determine the concentration of certain metal ions, among them sodium , potassium , lithium , and calcium . Group 1 and Group 2 metals are quite sensitive to Flame Photometry due to their low excitation energies. In principle, it is a controlled flame test with the intensity of the flame colour quantified by photoelectric circuitry. The intensity of the colour will depend on the energy that had been absorbed by the atoms that was sufficient to vaporise them. The sample is introduced to the flame at a constant rate. Filters select which colours the photometer detects and exclude the influence of other ions. Before use, the device requires calibration with a series of standard solutions of the ion to be tested. Flame photometry is crude but cheap compared to Emission spectroscopy flame emission spectroscopy , where the emitted light is analysed with a monochromator. Its status is similar to that of the Colorimeter chemistry colorimeter which uses filters compared to the Spectrophotometry spectrophotometer which uses a monochromator . It also has the range of metals that could be analysed and the limit of detection are also considered References pre http www.articlesbase.com science articles flame photometers and how they work 2640727.html pre Category Inorganic chemistry ca Fot metre de flama pl Fotometria p omieniowa ... more details
Other senses for the amalgamation of gold into mercury, see Mercury element Gold and silver mining absorption of gold into mercury . For the absorption of light in spectrophotometry, see spectrophotometry . File Absorber.svg thumb 250px Laboratory absorber. 1a CO sub 2 sub inlet 1b H sub 2 sub O inlet 2 outlet 3 absorption column 4 packing. Absorption , in chemistry , is a physical or chemical phenomenon or a Process science process in which atom s, molecules , or ion s enter some bulk phase gas , liquid , or solid material. This is a different process from adsorption , since molecules undergoing absorption are taken up by the volume, not by the surface as in the case for adsorption . A more general term is sorption , which covers absorption, adsorption , and ion exchange . Absorption is a condition in which something takes in another substance. ref name Organic chemistry If absorption is a physical process not accompanied by any other physical or chemical process, it usually follows the Nernst partition law the ratio of concentrations of some solute species in two bulk phases in contact is constant for a given solute and bulk phases Citation needed date December 2007 math frac x 1 x 2 text constant K N x,12 math The value of constant K sub N sub depends on temperature and is called partition coefficient . This equation is valid if concentrations are not too large and if the species x does not change its form in any of the two phases 1 or 2 . If such molecule undergoes association or Dissociation chemistry dissociation then this equation still describes the equilibrium between x in both phases, but only for the same form concentrations of all remaining forms must be calculated by taking into account all the other equilibria. ref name Organic chemistry In the case of gas absorption, one may calculate its concentration by using, e.g., the Ideal gas law , c p RT. In alternative fashion, one may use partial pressure s instead of concentrations. In many processes importa ... more details
Frank Scott Hogg June 26, 1904 &ndash January 1, 1951 was born to Dr. James Scott Hogg and Ida Barberon in Cambridge, Ontario Preston , Ontario . After earning and undergraduate degree from the University of Toronto, Hogg received the second doctorate in astronomy awarded at Harvard University in 1929 where he pioneered in the study of spectrophotometry of star s and of Electromagnetic spectrum spectra of comet s. ref cite web url http www.rasc.ca journal pdfs 1999 12.pdf title Canadian Astronomers who Earned the Ph.D. at Harvard in the Shapley Era work Hoffleit, Dorrit. Journal of the Royal Astronomical Society of Canada. December 1999, Volume No. 3, Number 6. 262 271 accessdate 2007 03 08 ref In September 1931, he married Helen Sawyer Hogg . During World War II, he developed a two star sextant for air navigation. He was the head of the Department of Astronomy at the University of Toronto and director of the David Dunlap Observatory from 1946 until his death. During this time he pursued the observatory s major research program to study the motions of faint stars in the line of sight. ref cite web url http www.thecanadianencyclopedia.com index.cfm?PgNm TCE&Params A1ARTA0003807 title Hogg, Frank Scott work Millman, Peter M. The Canadian Encyclopedia accessdate 2007 03 08 ref The crater Hogg crater Hogg on the Moon is co named for him and Arthur Robert Hogg Arthur Hogg . Notes references External links http www.thecanadianencyclopedia.com index.cfm?PgNm TCE&Params A1ARTA0003807 Frank Scott Hogg Persondata Metadata see Wikipedia Persondata . NAME Hogg, Frank Scott ALTERNATIVE NAMES SHORT DESCRIPTION DATE OF BIRTH June 26, 1904 PLACE OF BIRTH DATE OF DEATH January 1, 1951 PLACE OF DEATH DEFAULTSORT Hogg, Frank Scott Category 1904 births Category 1951 deaths Category Canadian astronomers Category University of Toronto alumni Category Harvard University alumni Category People from Cambridge, Ontario Category University of Toronto faculty Category Canadian people of Scotti ... more details
Unreferenced date December 2009 DISPLAYTITLE ortho Nitrophenyl galactoside Chembox Name ortho Nitrophenyl galactoside ImageFile ONPG structure.png ImageSize 200px IUPACName 2R,3R,4S,5R 2 Hydroxymethyl 6 2 nitrophenoxy oxane 3,4,5 triol OtherNames 2 Nitrophenylgalactoside Abbreviations ONPG Section1 Chembox Identifiers CASNo 19710 96 4 PubChem 123646 SMILES O N O C1 CC CC C1O C H 2O C H CO C H O C H O C H 2O MeSHName 2 nitrophenylgalactoside Section2 Chembox Properties Formula C sub 12 sub H sub 15 sub NO sub 8 sub MolarMass 301.249 Appearance Density MeltingPt BoilingPt Section3 Chembox Hazards Solubility MainHazards FlashPt Autoignition Lowercase ortho Nitrophenyl galactoside ortho Nitrophenyl galactoside ONPG is a Colorimeter chemistry colorimetric and spectrophotometry spectrophotometric substrate biochemistry substrate for detection of beta galactosidase activity. This compound is normally colorless. However if galactosidase is present, it Hydrolysis hydrolyzes the ONPG molecule into galactose and ortho nitrophenol . The latter compound has a yellow color that can be used to check for enzyme activity by means of a Colorimeter chemistry colorimetric assay at 420 nm wavelength . galactosidase is required for lactose utilization, so the intensity of the color produced can be used as a measure of the enzymatic rate. Though ONPG mimics lactose and is hydrolyzed by galactosidase, it is unable to act as an inducer for the lac operon. Without another lactose analog that can act as an inducer, such as IPTG , galactosidase will not be transcribed and ONPG will not be hydrolyzed. Glycosides DEFAULTSORT Ortho Nitrophenyl Galactoside Category Galactosides Nitrophenyl galactoside, ortho Category Nitrobenzenes Biochem stub de O Nitrophenyl D galactopyranosid fr Ortho nitroph nyl galactoside ... more details
Orphan date February 2009 SIAscopy measures the amount of haemoglobin , melanin and collagen in the stratum corneum , Epidermis skin epidermis and dermis to a depth of 2 mm, and identifies whether melanin is present in the epidermis or the dermis. The information is presented as SIAscans, which show how these components vary over the skin. SIAscopy makes use of the way light interacts with skin the way it scatters or bounces and the amount absorbed by cells and other structures and how this varies for different wavelengths or colours of light and is based on Symon Cotton s Thesis PhD thesis . ref Cotton S. D 1998 A non invasive Medical imaging imaging system for assisting in the diagnosis of Melanoma malignant melanoma . PhD thesis. University of Birmingham Birmingham University , UK ref ref M. MONCRIEFF,S. COTTON, E. CLARIDGE AND P. HALL 2002 Spectrophotometric intracutaneous analysis a new technique for imaging pigmented skin lesions, British Journal of Dermatology 2002 146 448 457. ref Due to the multi layered structure of the skin, and because the most prominent chromophores have slowly varying spectral properties, it is possible to generate models which can predict the method of light transport within skin. This allows analysis of the skin using broadband Spectrophotometry spectrophotometric techniques. The device used to capture the information is a SIAscope. In order to generate the model, simulations are run for hundreds of thousands of different combinations of haemoglobin, melanin, collagen and dermal melanin. The result of each simulation represents how the camera would respond if it was to image the corresponding combination of skin chromophore s. This information is stored, and then interrogated during each scan in order to generate SIAscans. Each SIAscan is a bitmap representing the concentration of each chromophore on every pixel. Image siaa.JPG thumb Handheld SIAscanner Image 12 NewStripRot90.jpg thumb Example SIAscan of melanoma, From Left colo ... more details
Unreferenced date May 2009 In spectrophotometry , the Compton edge is a feature of the spectrograph that results from the Compton scattering in the scintillator or Particle detector detector . When a gamma ray scatters off the scintillator but escapes, only a fraction of its energy is registered by the detector. This leads to a spectrum of gamma rays in the data that is not really there. The highest energy that occurs from this process is the Compton edge. Background File Am Be SourceSpectrum.jpg right thumb 300px Gamma spectrum of a radioactive Am Be source. In a Compton scattering process, an incident photon collides with an electron in a material. The amount of energy exchanged varies with angle, and is given by the formula math frac 1 E prime frac 1 E frac 1 m text e c 2 left 1 cos theta right math or math E prime frac E 1 frac 1 cos theta E m text e c 2 math E is the energy of the incident photon. E is the energy of the outgoing photon, which escapes the material. math m text e math is the mass of the electron. c is the speed of light. math theta math is the angle of deflection for the photon. The amount of energy transferred to the material varies with the angle of deflection. As math theta math approaches zero, none of the energy is transferred. The maximum amount of energy is transferred when math theta math approaches 180 degrees. math E T E E prime math math E text Compton E T text max frac 2E 2 m text e c 2 2E math It is impossible for the photon to transfer any more energy via this process, hence there is a sharp cutoff at this energy giving rise to the name Compton edge . See also Gamma ray spectroscopy Compton suppression DEFAULTSORT Compton Edge Category Spectroscopy Physics stub ar ... more details
Multiple issues no footnotes December 2010 orphan February 2009 cleanup September 2007 LBOZ is a coefficient used in spectrophotometry to estimate selectivity amount of overlapping of spectrum spectra in quantitative manner. It is named after its creators Lorber, Bergmann, von Oepen, and Zinn. Definition Image lboz spectra.png thumb right 300 px Sample synthetic spectra of four components Let math mathbf X math be a matrix of the spectra absorbances , where the k rows correspond to the components in mixture and n columns correspond to the sequence of wavelengths. The LBOZ criterion for k th component is calculated from the following formula math xi k frac 1 mathbf X k row mathbf X k col math where math mathbf X math means a pseudoinverse of the matrix and math cdots math means an Euclidean space euclidean length of a vector. Properties The image above show synthetic Gaussian function gaussian spectra. The LBOZ criteria are 0.561 for black compound, 0.402 for red compound, 0.899 for green and 0.549 for blue. LBOZ always lie in range 0,1 and has strong mathematical sense it presents the amount of spectral signal which is not overlapped by the others. Hence, the uncertainty of a compound quantity increases by math 1 xi math in presence of the other compounds. In this case, the highest uncertainty is expected during determination of red compound theoretically 2.38 times greater than during determination of its compound alone. References A. Lorber, Anal. Chem. 58 1986 1167. A. Lorber, A. Harel, Z. Goldbart, I.B. Brenner, Anal. Chem. 59 1987 1260. G. Bergmann, B. von Oepen, P. Zinn, Anal. Chem. 59 1987 2522. Category Spectroscopy pl LBOZ ... more details
orphan date March 2010 Alexis Spectral Data is a software developed for colour matching processes that calculates from available spectral data the colour numbers used by computers to display colours on screen. It displays the colour for each reflectivity spectral reflectance curve and records the calculated tristimulus trichromatic values and colour numbers along with the spectral curves. This eliminates the need to scan the samples separately with a Truecolour Scanner while creating the database. The spectral data can be introduced manually as a series of reflectivity reflectance values at wavelength s measured in different standard illuminant s with an arbitrary but fixed increment that must be kept for each spectral curve throughout the creation of the whole database. Therefore, older UV VIS spectrophotometry Spectrophotometers that can t be Interface computer science interfaced with computers can also be used for creating the database needed for colour matching. ref Razvan Ion M. Preda, Maria Marcela Savu, Aurelia Meghea, Corneliu Tarabasanu Mihaila, Mathematical model for colour matching applied in sheepskin dyeing , IULTCS Centenary Congress, London 1997, Congress Proceedings, 798 803. ref Alexis Spectral Data determines the whiteness degree in a less time consuming method, which permits storage and easier handling of the obtained data. ref Maria Marcela Savu, Razvan Ion Preda, Florin Vrejoiu, Determination of whiteness degree for various leather support, 11th Congress of the Leather and Shoe Industries, Hungary 1998, 451 ref Alexis Spectral Data can export the tristimulus trichromatic values , calculated from the spectral curves, to Alexis Analyser, software that handles only trichromatic data. The earliest information about the development of this software comes from a paper published by a student at the Politehnica University of Bucharest University Politehnica Bucharest in 1993 ref Razvan Ion M. Preda, Mircea Popescu, True RGB colour analysis , Chemistry a ... more details
recommended in the corresponding years. If someone wants to work in the Spectrophotometry report too, here it is for reference ref cite journal title Spectrophotometry Report of OSA Progress Committee ... more details
metabolism enzymes, ref Kalckar, H.M. and Shafran, Manya. Differential Spectrophotometry of Purine ... Chemistry 167 1947a 429 443. ref ref Kalckar, H.M. and Bessmann, Alice N. Differential Spectrophotometry ... Spectrophotometry of Purine Compounds by Means of Specific Enzymes III. Studies of the Enzymes .... Differential Spectrophotometry of Purine Compounds by Means of Specific Enzymes I. Determination ... and Bessmann, Alice N. Differential Spectrophotometry of Purine Compounds by Means of Specific Enzymes ... , ref Kalckar, H.M. and Shafran, Manya. Differential Spectrophotometry of Purine Compounds by Means ... more details
distinguish L scher color test File Felix von Luschan Skin Color chart.svg thumb 300px Von Luschan s chromatic scale File Unlabeled Renatto Luschan Skin color map.svg thumb right 300px Geographic distribution of skin colors Von Luschan s chromatic scale is a method of classifying skin color . It is also called the von Luschan scale or von Luschan s scale . It is named after its inventor, Felix von Luschan . The equipment consists of 36 opaque glass tiles which were compared to the subject s skin, ideally in a place which would not be exposed to the sun such as under the arm . The von Luschan scale was used to establish racial classification s of entire cognate population s according to skin color. The von Luschan scale was used extensively throughout the first half of the 20th century in Race classification of human beings race studies and anthropometry . However, it was considered problematic, even by its practitioners, because it was very inconsistent. In many instances, different investigators would give different readings of the same person. The von Luschan scale was largely abandoned by the early 1950s, replaced instead by methods utilizing reflectance spectrophotometry . Fitzpatrick scale main Fitzpatrick scale A less finely tiered scale of six skin type s, called the Fitzpatrick scale , was introduced in 1975 by Harvard dermatologist Thomas B. Fitzpatrick to describe the sun tanning behaviour of various skin types, without any racial classification connotations, as follows ref Fitzpatrick TB Soleil et peau Sun and skin . Journal de M decine Esth tique 1975 2 33 34 ref class wikitable Type von Luschan scale Also called I 1 5 Very light or white, Celts modern Celtic type ref name nicknames these are commonly encountered names for the types, e.g. http www.hqusareur.army.mil 2m2 skin Skintest.htm US Army Healthy Skin Campaign Dead link date March 2010 http www.goldnbrown.co.uk type.html goldnbrown.co.uk , http www.hautzone.ch dermatologie pigmented man&sun.htm ha ... more details
Protein methods are the techniques used to study protein s. There are genetic methods for studying proteins, methods for detecting proteins, methods for isolating and purifying proteins and other methods for characterizing the structure and function of proteins, often requiring that the protein first be purified. Genetic methods conceptual translation many proteins are never directly sequenced, but their sequence of amino acids is known by conceptual translation of a known mRNA sequence. See genetic code . site directed mutagenesis allows new variants of proteins to be produced and tested for how structural changes alter protein function. insertion of protein tags such as the His tag . See also green fluorescent protein . evolutionary analysis of sequence changes in different species using software such as BLAST . Proteins that are involved in human diseases can be identified by matching allele s to disease and other phenotypes using methods such as Genetic linkage calculation of LOD scores . Detecting proteins microscopy, Immunostaining protein immunostaining Immunoprecipitation Protein immunoprecipitation Immunoelectrophoresis Immunoblotting Bicinchoninic acid assay BCA Protein Assay Western blot Spectrophotometry Enzyme assay Protein purification Protein Isolation chromatography methods Ion exchange , Size exclusion chromatography Size exclusion chromatography or Gelfiltration , Affinity chromatography Protein Extraction and Solubilization Protein Concentration Determination Methods, Bradford protein assay Concentrating Protein Solutions Gel electrophoresis Gel Elecdsis Under denaturing conditions Gel Electrophoresis Under non denaturing conditions 2D Gel Electrophoresis Electrofocusing Protein structures X ray crystallography Protein NMR Protein DNA interactions ChIP on chip Chip Sequencing DamID Microscale Thermophoresis Other methods Hydrogen deuterium exchange Mass spectrometry Molecular dynamics Protein structure prediction Protein sequencing Protein structu ... more details
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