Multiple internal selection

Latexes of synthetic resins are identified by ir spectrometry. Selective extraction with organic solvents is used to obtain purified fractions of the polymers for spectrometric identification. Polymeric films can be identified by the multiple internal reflectance ir technique, if the film is smooth enough to permit intimate contact with the reflectance plate. TAPPI and ASTM procedures have not been written for these instmmental methods, because the interpretation of spectra is not amenable to standardization. 

The above examples demonstrate the DSR concept as a useful approach to generate and interrogate simultaneously complex systems for different applications. A range of reversible reactions, in particular carbon-carbon bond-formation transformations, was used to demonstrate dynamic system formation in both organic and aqueous solutions. By applying selection pressures, the optimal constituents were subsequently selected and amplified from the dynamic system by irreversible processes under kinetic control. The DSR technique can be used not only for identification purposes, but also for evaluation of the specificities of selection pressures in one-pot processes. The nature of the selection pressure applied leads to two fundamentally different classes external selection pressures, exemplified by enzyme-catalyzed resolution, and internal selection pressures, exemplified by transformation- and/or crystallization-induced resolution. Future endeavors in this area include, for example, the exploration of more complex dynamic systems, multiple resolution schemes, and variable systemic control. 

Stone applied the theory of Longuet-Higgins to deduce the character tables for the multiple internal rotation in neopentane and in octahedral hexa-ammonium metallic complexes [6]. Dalton examined the use of the permutation-inversion groups for determining statistical weights and selection rules for radiative processes in non-rigid systems [7]. Many applications of the Molecular Symmetry Groups have been reviewed later by Bunker [8,9]. 

Sysi-Aho, M. et al., Normalization method for metabolomics data using optimal selection of multiple internal standards, BMC Bioinform., 8, 93, 2007. 

Adapted from multiple internally corroborated sources most comprehensive is the USDA National Nutrient Database for Standard Reference, Release 18, Protein (g) Content of Selected Foods per Common Measure, available at URL www.nal.us da.gov/fnic/foodcomp/Data/SR18/nutrlist/sr18a203.pdf... 

A specific batch bioreactor application depends on multiple internal and external factors however, general rules of thumb and process-specific improvements can be employed to make a smarter and more profitable selection. Batch bioreactor selectivity is based on the following factors economic balance, production scale, reaction times, production flexibility, and the nature of the process and product (Donati and Paludetto, 1999). Typically, batch bioreactors are used for smaller operations, specialty products, long growth periods (bioreactor of choice by elimination), operations in which flexibility is vital, unsteady processes, and experimental development (Donati and Paludetto, 1999 Simon et al., 2006 Williams, 2002). 

In addition to the quadrupole mass spectrometer, which is used relatively frequently in water analysis, electron impact ionization, chemical ionization, qualitative multiple ion selection and quantitative multiple ion selection (with a certain mass as the internal standard and direct admission of the substances, e.g. for mass calibration) are also used. 

Velazquez, M. A., D. Claudio, and A. R. Ravindran. 2010. Exp>erimenfs in multiple criteria selection problems with multiple decision makers. International Journal of Operational Research. 7(4) 413—428. 

MS condition — An API 4000 equipped with a Turbo Ionspray from Applied Biosystems was used as the mass detector and [M + NH4]+ was chosen as the precursor ion for multiple reaction monitoring (MRM) due to the lack of protonated molecular ions. A transition of m/z 434.4 — 273.2 was chosen for paricalcitol and m/z 450.5 —> 379.2 was selected for the structure analog internal standard. 

The software tools accompanying the QTRAP MS/MS allow set-up of multiple selected reaction monitoring (SRM) transitions for all likely metabolites after the major product ion transitions for the dosed compound are known. Because QTRAP MS/MS can monitor up to 100 SRM transitions during a single assay, the SRM transitions required for quantitation of the dosed compound and internal standard are obtained along with the possible metabolite transitions. During sample analysis, when a possible metabolite transition exceeds a preset threshold value, the QTRAP MS/MS performs an enhanced product ion (EPI) scan. When the assay is complete, the EPI scans can be used to determine whether the hits are metabolites, and if they are metabolites, what part of the molecule has changed. Thus, one analytical run provides both quantitative and metabolite information. 

Most industrial catalysts are heterogeneous catalysts consisting of solid active components dispersed on the internal surface of an inorganic porous support. The active phases may consist of metals or oxides, and the support (also denoted the carrier) is typically composed of small oxidic structures with a surface area ranging from a few to several hundred m2/g. Catalysts for fixed bed reactors are typically produced as shaped pellets of mm to cm size or as monoliths with mm large gas channels. A catalyst may be useful for its activity referring to the rate at which it causes the reaction to approach chemical equilibrium, and for its selectivity which is a measure of the extent to which it accelerates the reaction to form the desired product when multiple products are possible [1],... 

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