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Artykuły w czasopismach na temat "Selective fractionation":
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Frank, Uwe, Jana Dienstbier, Florentin Tischer, Simon E. Wawra, Lukas Gromotka, Johannes Walter, Frauke Liers i Wolfgang Peukert. "Multidimensional Fractionation of Particles". Separations 10, nr 4 (13.04.2023): 252. http://dx.doi.org/10.3390/separations10040252.
Streszczenie:
The increasing complexity in particle science and technology requires the ability to deal with multidimensional property distributions. We present the theoretical background for multidimensional fractionations by transferring the concepts known from one dimensional to higher dimensional separations. Particles in fluids are separated by acting forces or velocities, which are commonly induces by external fields, e.g., gravitational, centrifugal or electro-magnetic fields. In addition, short-range force fields induced by particle interactions can be employed for fractionation. In this special case, nanoparticle chromatography is a recent example. The framework for handling and characterizing multidimensional separation processes acting on multidimensional particle size distributions is presented. Illustrative examples for technical realizations are given for shape-selective separation in a hydrocyclone and for density-selective separation in a disc separator.
2
Martín-Ortiz, Andrea, Francisco Javier Moreno, Ana Isabel Ruiz-Matute i María Luz Sanz. "Selective biotechnological fractionation of goat milk carbohydrates". International Dairy Journal 94 (lipiec 2019): 38–45. http://dx.doi.org/10.1016/j.idairyj.2019.02.012.
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Furuya, Kenji. "Isotopic fractionation in interstellar molecules". Proceedings of the International Astronomical Union 13, S332 (marzec 2017): 163–74. http://dx.doi.org/10.1017/s1743921317006810.
Streszczenie:
AbstractThe level of isotopic fractionation in molecules provides insights into their formation environments and how they formed. In this article, we review hydrogen and nitrogen isotopic fractionation in low-mass star-forming regions. Interstellar molecules are significantly enriched in deuterium. The importance of the nuclear spin states of light species on deuterium fractionation and the usefulness of singly and doubly deuterated molecules as chemical tracers are discussed. Observations have revealed that molecules in prestellar cores are enriched in or depleted in15N depending on molecules. Compared with deuterium fractionation chemistry, our understanding of15N fractionation chemistry is not well established. We briefly discuss potential15N fractionation routes, i.e., isotopic-exchange reactions and isotopic selective photodissociation of N2. In addition, the selective freeze-out of15N atoms onto dust grains around the transition between N atoms and N2is discussed as a potential mechanism that causes the depletion of15N in the gas phase.
4
Ruiz-Aceituno, L., C. Carrero-Carralero, L. Ramos i M. L. Sanz. "Selective fractionation of sugar alcohols using ionic liquids". Separation and Purification Technology 209 (styczeń 2019): 800–805. http://dx.doi.org/10.1016/j.seppur.2018.09.026.
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Sun, Kai, Nobuko Suzuki, Zheyu Li, Ryoko Araki, Kosei Ueno, Saulius Juodkazis, Masumi Abe, Sumihare Noji i Hiroaki Misawa. "Electrophoretic chip for fractionation of selective DNA fragment". ELECTROPHORESIS 29, nr 19 (październik 2008): 3959–63. http://dx.doi.org/10.1002/elps.200700904.
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Ly, Linda, i Valerie C. Wasinger. "Peptide enrichment and protein fractionation using selective electrophoresis". PROTEOMICS 8, nr 20 (22.09.2008): 4197–208. http://dx.doi.org/10.1002/pmic.200701088.
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Damm, Cornelia, Danny Long, Johannes Walter i Wolfgang Peukert. "Size and Shape Selective Classification of Nanoparticles". Powders 3, nr 2 (17.05.2024): 255–79. http://dx.doi.org/10.3390/powders3020016.
Streszczenie:
As nanoparticle syntheses on a large scale usually yield products with broad size and shape distributions, the properties of nanoparticle-based products need to be tuned after synthesis by narrowing the size and shape distributions or via the removal of undesired fractions. The development of property-selective classification processes requires a universal framework for the quantitative evaluation of multi-dimensional particle fractionation processes. This framework must be applicable to any property and any particle classification process. We extended the well-known one-dimensional methodology commonly used for describing particle size distributions and fractionation processes to the multi-dimensional case to account for the higher complexity of the property distribution and separation functions. In particular, multi-dimensional lognormal distributions are introduced and applied to diameter and length distributions of gold nanorods. The fractionation of nanorods via centrifugation and by orthogonal centrifugal and electric forces is modeled. Moreover, we demonstrate that analytical ultracentrifugation with a multi-wavelength detector (MWL-AUC) is a fast and very accurate method for the measurement of two-dimensional particle size distributions in suspension. The MWL-AUC method is widely applicable to any class of nanoparticles with size-, shape- or composition-dependent optical properties. In addition, we obtained distributions of the lateral diameter and the number of layers of molybdenum disulfide nanosheets via stepwise centrifugation and spectroscopic evaluation of the size fractions.
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Penger, Jörn, Ralf Conrad i Martin Blaser. "Stable Carbon Isotope Fractionation by Methylotrophic Methanogenic Archaea". Applied and Environmental Microbiology 78, nr 21 (17.08.2012): 7596–602. http://dx.doi.org/10.1128/aem.01773-12.
Streszczenie:
ABSTRACTIn natural environments methane is usually produced by aceticlastic and hydrogenotrophic methanogenic archaea. However, some methanogens can use C1compounds such as methanol as the substrate. To determine the contributions of individual substrates to methane production, the stable-isotope values of the substrates and the released methane are often used. Additional information can be obtained by using selective inhibitors (e.g., methyl fluoride, a selective inhibitor of acetoclastic methanogenesis). We studied stable carbon isotope fractionation during the conversion of methanol to methane inMethanosarcina acetivorans,Methanosarcina barkeri, andMethanolobus zinderiand generally found large fractionation factors (−83‰ to −72‰). We further tested whether methyl fluoride impairs methylotrophic methanogenesis. Our experiments showed that even though a slight inhibition occurred, the carbon isotope fractionation was not affected. Therefore, the production of isotopically light methane observed in the presence of methyl fluoride may be due to the strong fractionation by methylotrophic methanogens and not only by hydrogenotrophic methanogens as previously assumed.
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Weidener, Dennis, Holger Klose, William Graf von Westarp, Andreas Jupke, Walter Leitner, Pablo Domínguez de María i Philipp M. Grande. "Selective lignin fractionation using CO2-expanded 2-methyltetrahydrofuran (2-MTHF)". Green Chemistry 23, nr 17 (2021): 6330–36. http://dx.doi.org/10.1039/d1gc01651b.
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Penín, L., S. Peleteiro, V. Santos, J. L. Alonso i J. C. Parajó. "Selective fractionation and enzymatic hydrolysis of Eucalyptus nitens wood". Cellulose 26, nr 2 (16.11.2018): 1125–39. http://dx.doi.org/10.1007/s10570-018-2109-4.
Rozprawy doktorskie na temat "Selective fractionation":
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Ly, Linda Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "Development of selective electrophoresis for proteins and peptides within proteomes". Publisher:University of New South Wales. Biotechnology & Biomolecular Sciences, 2008. http://handle.unsw.edu.au/1959.4/42126.
Streszczenie:
Analysis of complex protein samples is demanding due to the wide dynamic range of expression levels and the limited detection range of technology. Proteomics relies heavily on the development of new fractionation strategies to help reduce complexity, and overcome the technological and biological challenges associated with proteome analysis. Here, the development of a prototype instrument named ??Microflow MF10?? was explored to enrich for particular classes of proteins. The MF10 was found to have a number of advantages over commercially available fractionation systems. Due to the reduced separation electrode distance, fractionation was rapid, occuring within ~0.125 kVH over 2-6 fractions under native conditions but longer under denaturing conditions. As low as 2 ng peptide could be fractionated with recovery for downstream analysis achievable. The ability to alter protein charge by changing the pH (acidic (pI 3.6) to basic environments (pI 10.4)) allows selection of proteins based on charge/mobility, size, shape, buffer ionic strength, pH and field strength. Proteins <10 kDa are also not routinely analysed because current technology is unable to cater for this region of the proteome. Peptide enrichment using the MF10 was achieved using a 7-protein/peptide standard mix (1-25 kDa), to the 1-5 kDa fraction with simultaneous fractionation of the higher mass protein standards. Plasma was also used to enrich for the peptidome (< 5 kDa) in the presence of the proteome. Enrichment of 73 proteins inclusive of 22 proteins in the 1-25 kDa fraction was achieved compared to a total equivalent of 42 proteins from unfractionated plasma. Rare samples (≤ 106 cells) from stem cell populations or derived clinically are challenging due to the absolute limits in protein copy number and abundance. CD34+ haematopoietic stem cells and CD4+/CD8+ T-cells were used to develop fractionation methods and elucidate the cell differentiation process. MF10 fractionation and analysis by SDS-PAGE and LC-MS/MS revealed 24 differentially expressed proteins between the 3 cell populations, which may be involved in cell differentiation. To quantify these expression differences, iTRAQ with 2-D LC-MS/MS was applied. This study has highlighted the challenges associated with samples of limited quantity. It has been successful in understanding the effects of various conditions on the electrophoretic mobility of proteins, which in proteomics, has remained largely unexplored.
2
Wagner, Knut. "Development of a comprehensive on-line multidimensional high performance column liquid chromatography system for protein and peptide mapping with integrated size selective sample fractionation". [S.l.] : [s.n.], 2001. http://ArchiMeD.uni-mainz.de/pub/2001/0143/diss.pdf.
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Zhang, Rui. "Impact of emerging technologies on the cell disruption and fractionation of microalgal biomass". Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2548.
Streszczenie:
Ce travail de recherche se concentre sur l'extraction et le fractionnement des biomolécules à partir de microalgues par des traitements physiques: les champs électriques pulsés (CEP), les décharges électriques de hautes tensions (DEHT) et les ultrasons (US). Dans cette étude, trois espèces de microalgues Nannochloropsis sp., Phaeodactylum tricornutum (P. tricornutum) et Parachlorella kessleri (P. kessleri) ont été étudiées. Les espèces ont différentes formes cellulaires, structure et contenu intracellulaire. L'effet des techniques testées sur l'extraction des biomolécules a été mis en évidence à travers une analyse quantitative et qualitative: suivi du rendement des composés ioniques, des glucides, des protéines, des pigments et des lipides. Une étude comparative des traitements physiques (CEP, DEHT et US), à la même énergie, pour la libération des biomolécules intracellulaires à partir des trois espèces de microalgues, a permis de mieux comprendre les différents mécanismes de désintégration. Pour chaque microalgue, à la même énergie consommée, le traitement par DEHT s'est révélé le plus efficace en terme d'extraction des glucides, tandis que les US sont plus efficaces pour l'extraction des protéines et des pigments. Le traitement par CEP a été moins efficace en terme du rendement d’extraction. Cependant, la meilleure sélectivité (extraction des glucides) a été obtenue en utilisant les CEP ou les DEHT. Les prétraitements physiques (CEP, DEHT ou US) des suspensions plus concentrées suivis d'une homogénéisation haute pression (HHP) de suspensions diluées ont permis d'améliorer l'efficacité de l'extraction et de diminuer la consommation énergétique totale et le nombre de passages. Le prétraitement physique permet de réduire la pression mécanique de l’HHP, pour atteindre le même rendement d’extraction. Pour la valorisation maximale de la biomasse de microalgues, une procédure d'extraction assistée par DEHT (40 kV/cm, 1-8 ms) suivie de plusieurs étapes d'extraction aqueuses et non aqueuses semble être utile pour l'extraction sélective et le fractionnement de différentes biomolécules à partir de microalgues. Des effets significatifs du prétraitement HVED sur l'extraction par solvant organique des pigments (chlorophylles, caroténoïdes) et des lipides ont été observésThis research work focuses on extraction and fractionation of bio-molecules from microalgae using physical treatments: pulsed electric fields (PEF), high voltage electrical discharges (HVED) and ultrasonication (US) techniques. In this study, three microalgae species Nannochloropsis sp., Phaeodactylum tricornutum (P. tricornutum) and Parachlorella kessleri (P. kessleri) were investigated. These species have different cell shapes, structure and intracellular contents. The effects of tested techniques on extraction of bio-molecules have been highlighted in a quantitative and qualitative analysis by evaluating the ionic components, carbohydrates, proteins, pigments and lipids. A comparative study of physical treatments (PEF, HVED and US) at the equivalent energy input for release of intracellular bio-molecules from three microalgal species allowed us to better understand the different disintegration mechanisms. For each microalga at the same energy consumption, the HVED treatment proved to be the most efficient for extraction of carbohydrates, while the US treatment for extraction of proteins and pigments. In general, the smallest efficiency was observed for the PEF treatment. However, the highest selectivity towards carbohydrates can be obtained using the mild PEF or HVED technique. The preliminary physical treatments (PEF, HVED or US) of more concentrated suspensions followed by high pressure homogenization (HPH) of diluted suspensions allowed improving the extraction efficiency and decreasing the total energy consumption. The physical pretreatments permit to reduce the mechanical pressure of the HPH and number of passes, to reach the same extraction yield. For the maximum valorisation of microalgal biomass, extraction procedure assisted by HVED treatment (40 kV/cm, 1-8 ms) followed by aqueous and non-aqueous extraction steps seems to be useful for selective extraction and fractionation of different bio-molecules from microalgae. The significant effects of HVED pre-treatment on organic solvent extraction of pigments (chlorophylls, carotenoids) and lipids were also observed
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Rulence, Alexandre. "Mise en œuvre de procédés membranaires pour la séparation sélective de la nisine à partir de surnageants de culture complexes". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2023/2023ULILR034.pdf.
Streszczenie:
La nisine, une bactériocine produite par les bactéries lactiques du genre lactococcus présentent des propriétés physico-chimiques d'intérêt tel qu'une thermorésistance ainsi qu'une activité antimicrobienne contre certaines souches pathogènes alimentaires. Elle est actuellement la seule bactériocine reconnue comme GRAS (Generally Recognized As Safe) par la FDA (U.S. Food and Drug Administration) et donc la seule bactériocine pouvant être utilisée comme conservateur naturel en agroalimentaire. La nisine représente donc une alternative d'intérêt à l'utilisation de conservateur chimique. Cependant, la nisine est actuellement sous-exploitée du fait de problèmes liés à sa production et sa purification à grande échelle. En effet, les bactéries lactiques nécessitant des milieux riches et complexes rendent la production par fermentation coûteuse et peu rentable. De même, sa purification à l'échelle industrielle ne se fait actuellement que par des procédés à faible rendement tels que le foisonnement ou la précipitation aux sels couplés à des techniques chromatographiques.Dans le cadre de cette thèse, nous nous sommes donc d'abord intéressés à la recherche de co-produit pour la fermentation de Lactococcus lactis en tant qu'alternative à l'utilisation des milieux riches comme le MRS. Le lactosérum est actuellement le principal co-produit usuellement employé. La recherche de co-produits de grade alimentaire pour la production efficace et à faibles coûts de la nisine par fermentation pourrait répondre au problème actuel de rendement de la production. Différents hydrolysats de protéines issus de co-produits végétaux et de poissons ont été testés dans la production de la biomasse bactérienne et de la nisine à l'aide de deux souches productrices afin d'optimiser la production de nisine. Ces résultats ont permis de montrer une meilleure production avec la souche L.lactis UL719 en comparaison avec une souche commerciale. Ils ont aussi permis de montrer l'efficacité de certaines sources de peptones végétales et d'une peptone de poisson dans la production de nisine en comparaison avec le lactosérum et le milieu MRS. Durant ce travail, des alternatives à la purification de la nisine ont aussi été étudiées. Pour cela, des procédés d'électrodialyse (ED) et d'ultrafiltration (UF) ont été appliqués à la purification de la nisine. Une première étude de la purification par électrodialyse, non reportée dans la littérature pour la purification de la nisine, a été mise en place pour la purification d'une solution commerciale, mettant en évidence des phénomènes d'interaction de la nisine avec les membranes échangeuse d'ions. L'application de l'ED pour la purification de la nisine a aussi été mise en place sur le traitement d'un surnageant de culture complexe produit des suites des études de la production. L'utilisation du procédé d'ultrafiltration a aussi été étudiée pour la purification de la nisine à partir d'un surnagent de culture complexe, mettant en parallèle les résultats issus des deux types de procédés membranaires. Ces études ont donc permis de démontrer l'efficacité de l'UF et de l'ED dans la purification de la nisine, l'ED qui de plus pourrait s'inscrire dans une démarche écocirculaire, de la production de la nisine à l'aide de co-produit, à sa purification par le traitement des effluents salins issus de la précipitation aux sels de la nisine lors de sa purificationNisin, a bacteriocin produced by lactic acid bacteria (LAB) presents physicochemical properties such as a thermal resistance and an antimicrobial activity against food pathogens bacteria. Nisin is actually the only bacteriocins labelled as Generally Recognized As Safe (GRAS) by the U.S Food and Drug Administration (FDA) and is thus the only bacteriocin used as a natural preservative in the food industry, making it an interesting alternative to the use of chemical preservatives. However, its uses are hampered at industrial scale due to low yields et high cost linked to its production on commercial broth and its purification necessity the combination of low yields techniques such as salting out coupled with chromatography.In this case we investigated in this work the use of food grade by-product produces by the food industry in replacement of costly commercial broth. Several by-products composed of vegetal and fish peptones were tested for the production of nisin. Whey being the most used by-product employed for production of nisin and several bacteriocin, we tested and compared different vegetal and fish proteins hydrolyzates regarding biomass production and nisin yields obtained. Several vegetal and fish protein hydrolyzates were tested with two different strains of Lactococcus lactis in order to optimize nisin production. Results showed a greater nisin production using L.lactis UL 719 when compared to a commercial strain. Results also showed the efficacy of some vegetal and one fish by-product for the production of nisin when compared to whey medium and commercial broth MRS. During this work was also investigating alternatives for nisin purification. Electro- and pressure-driven membrane process were studied for nisin purification and especially ultrafiltration (UF) and electrodialysis for which no literature reported the use of ED for nisin purification. ED was applied to the purification of nisin from a commercial solution and from a cell-free supernatant produced with whey permeate as broth for fermentation. UF was applied to the purification of nisin from a cell-free supernatant and permit to compare UF and ED in this application. This work enables us to demonstrate nisin interaction with ion exchange membrane never reported and enable its purification with purification factor comparable to conventional method actually used. Moreover, we demonstrated the use of ED not only efficient for nisin purification but with the possibility to implement ED in an eco-circularity concept, from nisin production using by-products, to its purification with ED and the recycling of salts from saline effluent produced during nisin salting-out
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Lalari, Vikki Valjeet. "Fractionation of expressed milk for the selective collection of hindmilk by mothers who deliver premature infants". Thesis, 2002. http://hdl.handle.net/2429/13876.
Streszczenie:
Adequate weight gain is often difficult to achieve in premature infants due to
illness, high energy requirements, and suboptimal intakes. Feeding strategies to
enhance the energy and nutrient intake of premature infants fed small volumes are
necessary for individualizing nutritional care and promoting optimal growth. One
feeding strategy for premature infants fed maternal milk is to fractionate mothers' milk
into foremilk (low fat milk) and hindmilk (high fat milk) with the subsequent feeding of the
energy dense hindmilk fraction to promote weight gain. Published research on
fractionating expressed milk for the selective collection of hindmilk is limited.
The purpose of this study was to develop a fractionating protocol for the selective
collection of hindmilk produced by mothers of premature infants. The basis of the
fractionating protocol was to determine an acceptable method for separating expressed
milk into foremilk and hindmilk. Three fractionating methods, based on the visual
appearance of the milk, the milk expression time, and the volume of milk expressed,
were compared for efficacy (change in fat content and adequacy of hindmilk volume)
and practicality (subjective evaluation by mothers). The "Time" method was found to be
the most acceptable and practical fractionating method for the selective collection of
hindmilk. A regression equation for predicting the fat content of milk from the
creamatocrit value (determined by the Creamatocrit Method) was developed using a
large number of milk samples (n=155) with varying concentrations of fat. This equation,
fat (g/100mL) = [0.572 x (creamatocrit value)] - 0.18, was found to be more suitable for
estimating the fat content of milk in the present data set when compared to other
published equations. The Crematocrit Method can be a useful clinical tool as part of a
fractionating protocol for estimating the fat content of milk. This fractionating protocol is
suitable for mothers who produce a sufficient quantity of milk (>125%) relative to their
infant's prescribed enteral intake. The fractionating protocol developed in this study is
applicable for a clinical or research setting as the basis of a hindmilk feeding strategy to
promote weight gain in premature infants.
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Lee, Tsu-Lin, i 李祖霖. "Studies on Selective Hydroxylation of Aromatics and Stable Carbon Isotope Fractionation by Cytochrome P450 BM3 Variants". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/61422278843352190040.
Streszczenie:
博士國立臺灣科技大學
應用科技研究所
104
Cytochrome P450 BM3 is an iron heme protein in Bacillus megaterium；it is capable of binding with oxygen and proceeding oxidation of the natural substrate-fatty acids C12-C20 in length to form hydroxyl group at ω-1, ω-2 or ω-3 position. The corresponding gene of P450BM3 was replicated and inserted in a DNA vector via molecular bioengineering technology. The constructed DNA was transformed and cloned in Escherichia coli host to achieve the protein expression and reveal its function by the catalytic oxidation of hydrocarbons. Crystal structure from Protein Data Bank（PDB：1FAG）allows us to understand the environment around the active site. On the basis of these insights, we can redesign cytochrome P450BM3 to switch its substrates from natural substrate-fatty acids to simple aromatics by directed evolution including site-directed mutagenesis study. According to our rational design, in order to achieve our goal, the amino acid residues 328 or 330 have to be substituted with phenylalanine by site-directed mutagenesis techniques. The variants with single site, double, triple as well as four sites have been deliberated. From the catalysis that using benzene or toluene as substrates, single-site variants （Phe328 or Phe330）, double-sites variant（Phe328／Met401）, triple-sites variants （3mt, Ile47／Phe51／Phe328 and Phe47／Ser51／Phe328）and four-sites variant 3mt Phe328 are able to show the activities. Phe328 is a major site to present the activities towards benzene and toluene. The distribution of main product was changed to benzyl alcohol when 3mt combined with Phe328 in toluene catalysis. By comparison with other type oxygenase, i.e. non-heme iron monooxygenase, the variants of cytochrome P450BM3 can generate o-cresol but the membrane bound xylene monooxygenase can only achieve sp3 oxidation for benzyl alcohol formation when toluene used as the substrate. From the studies of stable carbon isotope fractionation, the three variants of cytochrome P450BM3 shifted the δ13C（‰） of phenol down to ca. -38 when using benzene (-31) as a substrate. For the catalysis that using toluene (-24) as a substrate, the product δ13C（‰）values of the benzyl alcohol are -24.4~-27.4 and those of o-cresol and p-cresol are at the range of -27.4~-36.5 and -25.7~-29.0, respectively. The derived 12C/13C kinetic isotope effects (1.03~1.09) for benzene oxidation (~1.04) are relatively bigger indicated the transition state of oxygenation related to the bond breakage of C-H bond and bond formation of C-O is mechanistically significant (central transition state). However, most of the 12C/13C kinetic isotope effects obtained for the formation of benzyl alcohol, o-cresol and p-cresol ranged from 1.00~1.03 suggest the processes of both sp2 and sp3 C-H bond breaking as well as C-O bond formation encounter either in a very early or late transition state expect to the case of 3mt A328F variant corresponding to the formation of o-cresol (KIE (12C/13C) ~ 1.07).
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Shiau, Kai Jung, i 蕭凱鐘. "A Novel Two–Step Enrichment Procedure for Fractionation and Selective Identification of Multiply and Singly Phosphorylated Peptides". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/24101832783251335952.
Streszczenie:
碩士國立暨南國際大學
應用化學系
97
Abstract Despite recent technical advances, comprehensive characterization of protein phosphorylation remains a challenge. We explored the possibility using a two–step enrichment procedure for fractionation and selective identification of multiply and singly phosphorylated segments from enzymatic digestion of complex proteins. The procedure involved isolation of multiply phosphorylated peptides from solution using polyarginine-coated nonadiamond and subsequent isolation of singly phosphorylated peptides from the same pool of solution using TiO2-coated magnetic probes. The two types of probes can be independently characterized by MALDI mass spectrometry and provide complementary datasets for phosphoproteomic analysis. In addition, the total number of identified phosphopeptides obtained by the two-step enrichment procedure was almost doubled than that obtained by IMAC, TiO2, or PA affinity-based methods without the use of additional biological material. Improvements to comprehensive phosphopeptide identification via the two-step enrichment procedure are discussed. To our knowledge, this is the first demonstration of the two-step enrichment procedure for selective isolation and fractionation of multiply and singly phosphorylated peptides from the same pool of peptides solution.
8
Wagner, Knut [Verfasser]. "Development of a comprehensive on-line multidimensional high performance column liquid chromatography system for protein and peptide mapping with integrated size selective sample fractionation / von Knut Wagner". 2001. http://d-nb.info/963262106/34.
Książki na temat "Selective fractionation":
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Walsh, D. M. Challenges to Evolutionary Theory. Redaktor Paul Humphreys. Oxford University Press, 2015. http://dx.doi.org/10.1093/oxfordhb/9780199368815.013.14.
Streszczenie:
Evolutionary theory has long been influenced by modern synthesis thinking, which focuses on the theoretical primacy of genes and the fractionation of evolution into four discrete, quasi-independent processes: (i) inheritance, (ii) development, (iii) mutation, and (iv) natural selection. Recent challenges to modern synthesis orthodoxy, leveled at the fractionation of evolution and the attendant theoretical privilege accorded to genes, are driven by empirical advances in the understanding of inheritance and development. This article argues that inheritance holism, the idea that the contribution of genes to the pattern of inheritance cannot generally be differentiated from the contribution of extragenetic causes, invalidates the modern synthesis conception of inheritance as the transmission of replicants. Moreover, recent empirical understandings of development erode the fractionated view of evolution, which has misconstrued the role of natural selection. Development not only involves inheritance and the generation of novelties but is the source of the adaptive bias in evolution.
Części książek na temat "Selective fractionation":
1
Ruiz-Ruiz, Federico, Jorge Benavides i Marco Rito-Palomares. "Affinity ATPS Strategies for the Selective Fractionation of Biomolecules". W Food Engineering Series, 97–121. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-59309-8_6.
2
Iwarson, S. "The Impact of Donor Selection on Virus Transmission". W Plasma Fractionation and Blood Transfusion, 139–42. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2631-1_17.
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Ahire, Vidhula, Niloefar Ahmadi Bidakhvidi, Tom Boterberg, Pankaj Chaudhary, Francois Chevalier, Noami Daems, Wendy Delbart i in. "Radiobiology of Combining Radiotherapy with Other Cancer Treatment Modalities". W Radiobiology Textbook, 311–86. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-18810-7_6.
Streszczenie:
AbstractIn this chapter, we address the role of radiation as treatment modality in the context of oncological treatments given to patients. Physical aspects of the use of ionizing radiation (IR)—by either photons, neutrons, or charged (high linear energy transfer) particles—and their clinical application are summarized. Information is also provided regarding the radiobiological rationale of the use of conventional fractionation as well as alternative fractionation schedules using deviating total dose, fraction size, number of fractions, and the overall treatment time. Pro- and contra arguments of hypofractionation are discussed. In particular, the biological rationale and clinical application of Stereotactic Body Radiation Therapy (SBRT) are described. Furthermore, background information is given about FLASH radiotherapy (RT), which is an emerging new radiation method using ultra-high dose rate allowing the healthy, normal tissues and organs to be spared while maintaining the antitumor effect. Spatial fractionation of radiation in tumor therapy, another method that reduces damage to normal tissue is presented. Normal tissue doses could also be minimized by interstitial or intraluminal irradiation, i.e., brachytherapy, and herein an overview is given on the principles of brachytherapy and its clinical application. Furthermore, details are provided regarding the principles, clinical application, and limitations of boron neutron capture therapy (BNCT). Another important key issue in cancer therapy is the combination of RT with other treatment modalities, e.g., chemotherapy, targeted therapy, immunotherapy, hyperthermia, and hormonal therapy. Combination treatments are aimed to selectively enhance the effect of radiation in cancer cells or to trigger the immune system but also to minimize adverse effects on normal cells. The biological rationale of all these combination treatments as well as their application in clinical settings are outlined. To selectively reach high concentrations of radionuclides in tumor tissue, radioembolization is a highly interesting approach. Also, radioligand therapy which enables specific targeting of cancer cells, while causing minimal harm surrounding healthy tissues is presented. A brief overview is provided on how nanotechnology could contribute to the diagnosis and treatment of cancer. Last but not least, risk factors involved in acquiring secondary tumors after RT are discussed.
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Patinha, C., A. Reis, E. da Silva i A. Sousa. "Selective sequential extractions for the solid-phase fractionation of arsenic". W Arsenic in the Environment - Proceedings, 360–62. CRC Press, 2014. http://dx.doi.org/10.1201/b16767-135.
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Oliveira, Helder de, Diego Vendramini i Jefferson Mortatti. "Geochemical aspects of heavy metal fractionation in eucalyptus soils". W GLOBAL HEALTH TRENDS AND PERSPECTIVES IN HEALTH SCIENCES. Seven Editora, 2023. http://dx.doi.org/10.56238/globalhealthprespesc-033.
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Aspects of heavy metals fractionation (Cu, Cr and Co) in main eucalyptus cultivated soils were investigated after total extraction by alkaline fusion and selective sequential extractions. The study aimed to identify the major geochemical fractions and phases involved in metal complexation. Possible pollution classes were investigated through index of geo-accumulation (Igeo), considering the local natural background level. Among the main soils, Typic Hapludox showed the highest concentrations of these metals. However, there was no contamination according to the calculated Igeo. The selective sequential extractions showed that, for most analyzed soil, there was a predominance of these metals in the residual phase (> 80%), compared to the bioavailable fraction, and in this case, an association with the geochemical phase of Fe oxides. Cultural treatments, performed in this region during the eucalyptus cultivation, did not have residual effects in terms of heavy metals in soils.
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Ireland, Adrian, i Darryl Shibata. "In situ genetic analysis with selective ultraviolet radiation fractionation (SURF)". W PCR3, 11–26. Oxford University PressOxford, 1997. http://dx.doi.org/10.1093/oso/9780199636327.003.0002.
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Abstract Genetic analysis of specific cells and tissues provides opportunities for better correlation of genotype with phenotype. Often the relative locations of cells are as important as or mere important than their cytological features. Therefore, in situ genetic analysis may yield insights difficult to obtain by other techniques.
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Shallice, Tim. "Contrasting domains in the control of action: The routine and the non-routine". W Processes of Change in Brain and Cognitive Development, 3–30. Oxford University PressOxford, 2006. http://dx.doi.org/10.1093/oso/9780198568742.003.0001.
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Abstract The Supervisory System model, in which there are two cognitive levels in the control action, is assessed. It is argued that there is a modulatory relation between the levels. It is further argued that standard connectionist variables, such as age of acquisition, familiarity, and frequency, are particularly useful for characterizing behavior produced by contention scheduling, the lower-level system, when Supervisory System function is impaired. By contrast, an analogy with symbolic AI models is used to theoretically motivate a fractionation of Supervisory System processing as created by a set of functionally selective and anatomically partially separable subsystems.
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Rickwood, David, Anthea Messent, i Dipak Patel. "Isolation and characterization of nuclei and nuclear subfractions". W Subcellular Fractionation, 71–106. Oxford University PressOxford, 1997. http://dx.doi.org/10.1093/oso/9780199634958.003.0003.
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Abstract The nucleus is the centre of a wide range of diverse activities that. are essential for the survival of the cell. The development of methods for the isolation and purification of functional nuclei, nuclear subfractions, and individual components have been central to understanding how the nucleus functions in the cell. However, given the space limitations of a single chapter, it is only possible to focus on a selection of the methods used for isolating and characterizing the various components of the nucleus and analyzing their functions. The reader will be referred to other, relevant practical manuals for details of other types of technique as appropriate.
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Tallon, Stephen, i Teresa Moreno. "Liquid–Liquid Extraction". W Chemical Processes for a Sustainable Future, 503–51. The Royal Society of Chemistry, 2014. http://dx.doi.org/10.1039/bk9781849739757-00503.
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Liquid–liquid extraction is an effective contacting method for mass transfer operations in a wide range of industrial processing operations. Evaluated using green chemistry criteria there is potential to reduce the environmental impact and energy cost of current and emerging manufacturing processes through selection of solvent systems that are non-toxic and are efficient and selective at fractionating target compounds. This chapter describes the key elements of liquid–liquid extraction processes and the criteria against which they should be evaluated. Current trends in process design and solvent selection are described, including the use of novel supercritical, ionic liquid and two-phase aqueous solvents. Examples are given of research in the extraction of organic compounds from microbiological systems which exemplify many green chemistry drivers towards low energy use, low environmental impact, and products that do not contain hazardous or undesirable artefacts of processing.
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Marriott, Ray. "The Application of Supercritical Carbon Dioxide Extraction of Functional Compounds". W Chemical Processes for a Sustainable Future, 603–27. The Royal Society of Chemistry, 2014. http://dx.doi.org/10.1039/bk9781849739757-00603.
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The use of sub-critical and supercritical CO2 can selectively extract functional molecules from complex raw materials often avoiding lengthy and costly purification steps. Many of these raw materials are themselves sustainable plant products or waste streams leading to integrated, sustainable and economic manufacturing using CO2 as the process solvent. This chapter examines sustainable sources of CO2, process technology and the application of this technology in the extraction and fractionation of oleochemicals, terpenoids, alkaloids and metals.
Streszczenia konferencji na temat "Selective fractionation":
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Steindl, Johannes, Rafael Eduardo Hincapie, Ante Borovina, Christoph Puls, Johann Badstöber, Gerhard Heinzmann i Torsten Clemens. "Improved EOR Polymer Selection Using Field-Flow Fractionation". W Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207700-ms.
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Abstract Various polyacrylamide polymers have been successfully applied in chemical EOR projects. These polymers are characterised by high molecular weights (MW) to achieve high viscosifying power. The molecular weight distribution (MWD) of the polymers has a major impact on polymer properties and performance. Measuring the molecular weight distribution is challenging using conventional methods. Field-Flow Fractionation (FFF) enables the determination of the distribution to select and quality check various polymers. Polymers with high molar masses (> 1 MDa) are used for EOR to obtain highly viscous aqueous solutions. The MWD of the polymers is crucial for the solution characteristics. Conventional analysis of polymers is performed using either viscometry – which is able to determine the average MW but does not give information on MWD, or size-exclusion chromatography – which is restricted to molecular weights of < 20 MDa. FFF is based on the analytes flowing at different speeds in a channel dependent on their size and mass. This effect leads to separation, which is then used to determine the MWD. FFF allows to determine the MW and MWD of various ultra-high molecular weight polyacrylamides (HPAAMs). The FFF measurements showed, that despite similar MWs are claimed, substantial differences in MWD are observed. This technology offered the quantification the MWD of HPAAMs up to a MW of 5 GDa. Furthermore, gyration radii of the HPAAM molecules were determined. Selecting polymers on viscosifying power only is not addressing issues related to different MW and MWDs such as selective polymer retention and degradation of the high molar mass part of the distribution. The results were used to improve the polymer selection for chemical EOR projects. Overall, this work presents a new technique for analysis of ultra-high molecular weight EOR polymers, which enables the possibility to determine the full range of polymer MWD. This available information enhances the EOR polymer selection process addressing selective polymer retention and mechanical degradation in addition to the viscosifying power of polymers.
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Shintaku, Hirofumi, i Juan G. Santiago. "Extraction and fractionation of RNA and DNA from single cells using selective lysing and isotachophoresis". W SPIE BiOS, redaktorzy Bonnie L. Gray i Holger Becker. SPIE, 2015. http://dx.doi.org/10.1117/12.2084981.
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Rojas, Andrea D., Eva M. Schmelz i Rafael V. Davalos. "Separation Analysis of Breast Cancer Progression Lines Using Contactless Dielectrophoresis". W ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53987.
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Selective separation and isolation of microparticles or cells based on their biophysical properties has become an essential step in laboratory use [1]. Techniques include field flow fractionation [2], fluorescent and magnetic activated cell sorting [3], laser tweezers [4] and dielectrophoresis [5]. The latter technique uses a particle’s intrinsic properties to its advantage without altering the original structure or disrupting the viability of the cell which is highly attractive for cancer research.
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Konagaya, Rimi, Hiroyuki Tsuboi, Takaaki Itai i Yoshio Takahashi. "Selective isotope fractionation of rubidium during adsorption on phyllosilicate minerals as a tracer of water-rock interaction". W Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.12849.
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Sakong, B. "Selective in vitro anthelmintic efficacy of Diospyros whyteana (Ebenaceae) active compounds derived using antifungal activity to guide fractionation". W GA 2017 – Book of Abstracts. Georg Thieme Verlag KG, 2017. http://dx.doi.org/10.1055/s-0037-1608296.
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Yrjas, Patrik, Bengt-Johan Skrifvars, Mikko Hupa, Juha Roppo, Marko Nylund i Pasi Vainikka. "Chlorine in Deposits During Co-Firing of Biomass, Peat, and Coal in a Full-Scale CFBC Boiler". W 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78097.
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Co-combustion of coal with biomass or firing biomass alone is increasingly used as a first step to meet the Finnish commitments under the Kyoto agreement. Fluidized bed combustors are commonly used when co-firing, however, even if FBC’s have a wide tolerance for different fuel qualities, co-combustion of biomass or firing biomass alone may lead to unwanted ash-related problems. A deposit measurement campaign was done, at the 550 MWth biofuelled CFB in Jakobstad, Finland. During the campaign a total of 16 different fuel blends were burned. The deposits were sampled with air-cooled probes with detachable rings. The deposits were sampled at two different locations, one where the flue gas temperature was about 730°C (probe surface temp. 540°C) and the second where the flue gas temperature was about 530°C (probe surface temp. 350°C). From every deposit sample three elemental analyses were done — one from the wind side, one from the lee side, and one from an angle of about 50° from the wind side. The analyses were done with a SEM/EDX analyzer. The fuels used during the measurement campaigns were sampled and analyzed. In addition to proximate and ultimate fuel analysis so called fuel fractionation was applied. The fractionation method is based on selective leaching by water, ammonium acetate, and hydrochloric acid, consecutively. After each leaching step the solutions are analyzed for the most important elements. The method can be used to determine how the elements are bound in the fuel and how they may behave during combustion. The analysis results from the measurement campaign and from the advanced fuel analysis were combined and are reported in this paper, with emphasis on the fate of chlorine.
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Boutière, B., D. Arnoux, J. Sampol, C. Masson, F. Hamon i E. Anglès-Cano. "DETERMINATION OF FREE CIRCULATING t PA AND MAXIMAL t PA CONTENT IN NORMAL HUMAN PLASMA USING A SPECTROPHOTO-METRIC METHOD". W XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644427.
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Recent studies indicate that tPA released by endothelial cells circulates in plasma as a complex with its inhibitor (PAI). Quantitative data have been difficult to obtain however, due to the interference of plasmin inhibitors and other activators on liquid-phase tPA assays. In the present study an activity test (SOFIA-tPA ; Anal. Biochem. 133:201, 1986) on solid-phase fibrin has been used to determine the physiological forms of tPA in normal plasma. In this assay an affinity separation step allows the selective binding of tPA to fibrin and the elimination of plasmin inhibitors and other activators (pro UK, UK). Fibrin-boypd tPA is subsequentely detected by adding plasminogen and a chromogenic substrate selective for plasmin. Under these conditions the reaction rate depends on the presence of tPA, tPA-PAI complexes and PAI present in plasma. Plasma from 38 normal human volunteers obtained before and after venous occlusion was tested. Free tPA was determined in undiluted plasma while the fibrinolytic potential (maximal tPA activity) of plasma was detected following dissociation of tPA-PAI complexes by dilution and acidification of plasma, i.e. euglobulin fractionation. A 1:2 to 1:5 dilution of euglobulins was necessary to obtain a maximal dissociation of precipitated complexes. A similar dilution induced dissociation of tPA-PAI complexes was obtained with plasma at pH 6.8. The amount of free detectable tPA increased as a function of the dilution of plasma until a plateau value (usually at dilution 1:20), which was similar to that observed with the euglobulins. Our results (see Table) indicate that most of the tPA in human plasma circulates as tPA-PAI complexes and that free tPA can be detected only in minute amounts. Plasma instead of euglobulins can be accurately used to detect both free (undiluted plasma) and total tPA (plasma diluted 1:20).
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Orozco-Duque, A., J. D. Martinez-Vargas, D. Novak, J. Bustamante i G. Castellanos-Dominguez. "Feature selection for discrimination of fractionation levels in atrial electrograms". W 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2014. http://dx.doi.org/10.1109/embc.2014.6943909.
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Borovina, Ante, Rafael E. Hincapie Reina, Torsten Clemens, Eugen Hoffmann, Jonas Wegner i Johannes Steindl. "Polymer Selection for Sandstone Reservoirs Using Heterogeneous Micromodels, Field Flow Fractionation and Corefloods". W SPE Improved Oil Recovery Conference. SPE, 2022. http://dx.doi.org/10.2118/209352-ms.
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Abstract Incremental oil recovery due to polymer flooding results from acceleration of oil production along flow paths and improving sweep efficiency. To achieve favorable economics, polymers should have a high viscosifying power and low adsorption. However, in addition, incremental oil production from various rock qualities needs to be maximized. We developed a workflow using a layered micromodel, corefloods and Field-Flow Fractionation (FFF) to determine the Molecular Weight Distribution (MWD) for the selection of polymers addressing heterogeneous reservoirs. We have designed micromodels consisting of two layers with different permeabilities, one four times larger than the other. The micromodel structure is based on the characteristics of a real sandstone core, with the dimensions 6 cm × 2 cm. These micromodels were used as preliminary screening of the polymers incorporating heterogeneity effects. Subsequently, single- and two-phase core experiments were performed to determine injectivity effects and displacement efficiency of the selected polymers. In addition, FFF was used to measure the molecular weight distribution, gyration radii and conformance of the polymers. Based on the workflow a polymer was selected. All polymers were tested at target viscosity at 7 1/s shear rate. Micromodel experiments showed that tested polymers are leading to improved sweep efficiency of heterogeneous structure. The displacement efficiency within the higher permeable layer was similar for the investigated polymers whereas the oil recovery from the lower permeable layer showed differences. FFF revealed that the MWD's of the tested polymers were different. The MWD of one of the polymers showed a large number of larger molecules compared with the other polymers. This polymer did not lead to the highest oil recovery in the micromodel. Injectivity and propagation of the higher MW polymer in both single- and two-phase core-floods was falling behind the other polymers. Measurements of the MWD of the core effluent showed that for all tested polymers the larger molecules are initially retained more than the smaller molecules. The polymer with the smallest molecules and narrow MWD showed the best propagation characteristics in the core. Owing to the good performance of this polymer in terms of sweep efficiency improvement, injectivity, and propagation, this polymer was selected for a field application. Therefore, the novelty presented here can be summarised as follow: Heterogeneous micromodels were used to screen polymers for one-dimensional displacement efficiency and sweep efficiency effects Single- and two-phase core floods in combination with Field-Flow Fractionation revealed the impact of the molecular weight distribution (MWD) on polymer injectivity, propagation and retention Selection of polymers need to include MWD to find the most effective polymer Polymer selection needs to take near-wellbore and reservoir effects (micro- and sweep efficiency in heterogeneous reservoirs) into account
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Grinco, Marina, Alexandru Marina, Natalia Birca, Daniel Boscanean, Alic Barba, Vladilena Girbu, Nicon Ungur i Veaceslav Kulcitki. "Pomolic acid from apple pomace: quantitative determination by heteronuclear two-dimentional QNMR and preparative isolation". W Scientific seminar with international participation "New frontiers in natural product chemistry". Institute of Chemistry, Republic of Moldova, 2023. http://dx.doi.org/10.19261/nfnpc.2023.ab14.
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Pomolic acid (PA) is a pentacyclic triterpenic acid isolated from apples by Brieskorn and Wunderer in 1967 [1]. Its highly relevant biological activity profile came recently into focus and there have been many reports on the content of PA in different plant sources [2]. Quite surprisingly, the general perception of low PA content in plants persists and this information hinders its broader investigation as a compound of pharmaceutical and nutraceutical potential. The main aim of the current work was quantitative determination of pomolic acid in apple pomace by two-dimensional heteronuclear NMR correlation spectroscopy. The dried and grinded apple pomace was extracted with solvents of moderate polarity, including ethanol, ethylacetate and dimethylcarbonate under conditions of ultrasound assisted extraction. The overall extraction time did not exceed 3 hours. Fractionated extracts were obtained on the separation of acidic and neutral part, followed by selective extraction with solvent series of increasing polarity (petroleum ether, dichloromethane, ethylacetate). The content of PA in the obtained extracts was determined basing on 2D NMR HSQC experiment according to a recently elaborated protocol [3]. The quantification was based on integration of cross peaks corresponding to selected protons of PA and methyl 2,4-dinitrobenzoate as internal standard. The results showed that the highest content of PA was observed in ethylacetate (13.7%) and dimethylcarbonate (9.5%) extracts. Ethanol extracts displayed lower PA content (4.6%) in extracts and higher material recovery as expressed in percentage PA of dry weight. It was also demonstrated that selective extracts fractionations can provide enriched PA samples on avoiding the laborious chromatographic separations. The broad availability of apple pomace as a by-product of apple juice production ensures an excellent perspective for the preparative isolation of pomolic acid which could be a valuable raw material for the food and pharmaceutical industries.