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Статті в журналах з теми "Phosphorus oxidation state"
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Pasek, Matthew, and Kristin Block. "Lightning-induced reduction of phosphorus oxidation state." Nature Geoscience 2, no. 8 (July 13, 2009): 553–56. http://dx.doi.org/10.1038/ngeo580.
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Pokrovskiy, Valeriy A. "Temperature-Programmed Desorption Mass Spectrometry (TPDMS) of Dispersed Oxides." Adsorption Science & Technology 14, no. 5 (October 1996): 301–17. http://dx.doi.org/10.1177/026361749601400505.
Повний текст джерелаАнотація:
Temperature-programmed desorption mass spectrometry (TPDMS) is discussed with reference to studies of modified pyrogenic oxides. Simple theoretical models are presented in order to allow an approximate analytical treatment of TPDMS data. The ‘unimolecular’ decomposition of alkoxide groups was studied. The rate constants of the reactions were derived from TPDMS measurements. The kinetics of thermal transformations of phosphorous and phosphoric acids on a pyrogenic silica surface were investigated by TPDMS. Oxidation–reduction reactions in samples containing phosphorous acid resulted in the removal of molecular phosphorus (P4). Two stages of phosphorus evolution were observed which were attributed to the disproportion of phosphorus in the surface monolayer (high-temperature stage) and in the bulk layers (low-temperature stage). The biologically active samples obtained by adsorption of cyanocobalamine, glucose and raffinose on ultrafine oxide surfaces were studied via a combination of temperature-programmed desorption and solid-state thermal analysis mass spectrometry (TPD/TA MS). The role of the charged cobalt atom and of the propionamide and benzimide groups in the adsorption mechanism is discussed. It was shown that the adsorption of cyanocobalamine on the silica surface transformed the propionamide group to a weakly bound form. TPD/TA MS data were obtained confirming the stable adsorption of glucose and raffinose on an ultrafine pyrogenic silica surface modified by amino groups.
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Kumar, Rakesh, Dinesh Panday, and Seema Kothari. "Kinetics and Mechanism of the Oxidation of Oxyacids of Phosphorus by Benzimidazolium Dichromate." Progress in Reaction Kinetics and Mechanism 36, no. 4 (November 2011): 352–60. http://dx.doi.org/10.3184/146867811x13103063934104.
Повний текст джерелаАнотація:
Oxidation of some lower oxyacids of phosphorus by benzimidazolium dichromate results in the formation of the corresponding oxyacids containing phosphorus in a higher oxidation state, via an intermediate complex formation.
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Oh, Kyoung Hun, Sung Won Jung, and Keun Su Kim. "Tracing the initial state of surface oxidation in black phosphorus." Applied Surface Science 504 (February 2020): 144341. http://dx.doi.org/10.1016/j.apsusc.2019.144341.
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Nasirov R.,, Kuspanova B.,, Kalauova A.S.,, and Satenov K.G.,. "BINDING d-ELEMENT OF THE 4TH PERIOD OF V-GROUP OF THE PERIODIC SYSTEM OF D.I. MENDELEYEV AND ITS PARAMAGNETIC PROPERTIES." SERIES CHEMISTRY AND TECHNOLOGY 5, no. 443 (October 2020): 92–98. http://dx.doi.org/10.32014/2020.2518-1491.85.
Повний текст джерелаАнотація:
Vanadium is a connecting element between the main subgroup VA and the subgroup VB. In the opinion of B.V. Nekrasov, if we compare the VВ group of vanadium elements with the valence states of P and Аs VА main subgroup, then in the oxidation states of -3, 0, +3 arsenic is an analogue of phosphorus, and in the oxidation state +5, it will not be an analogue of phosphorus. In contrast, in the low oxidation degrees of vanadium, it differs from phosphorus, and in the oxidation state of +5 vanadium is not a complete analogue of phosphorus. The similarity of the electronic configuration of atoms for vanadium and phosphorus in the +5 oxidation state specifies the similarity of the properties of their chemical compounds. When comparing vanadium and its compounds with elements of the VA subgroup, we conclude that vanadium is a binding element between the VA subgroup and the VB subgroup and the compounds have similar properties. As a result of many years of work, it was found that vanadium in the penta- and tetravalent states has paramagnetic properties. In crude oil, it is in a tetravalent state. In order to improve the standard photocalorimetric method for determining vanadium in oil and petroleum ashes, a more rapid method was proposed for estimating the total concentration of vanadium based on the interaction of V2O5 with concentrated hydrochloric acid. Studies of the EPR spectra of porphyrin complexes with transition metals such as copper were of great importance in the identification of natural porphyrin complexes. In the course of comparison of experimental works of paramagnetic properties of vanadium and phosphorus with each other, it can be said that their application is of great practical importance in different fields of science. Summing up the results of studying the reduction of triphenylphosphine with an alkali metal, we proposed a scheme for the splitting of triphenylphosphine, including the formation of radical anions.
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Waters, Jordan B., Thomas A. Everitt, William K. Myers, and Jose M. Goicoechea. "N-heterocyclic carbene induced reductive coupling of phosphorus tribromide. Isolation of a bromine bridged P–P bond and its subsequent reactivity." Chemical Science 7, no. 12 (2016): 6981–87. http://dx.doi.org/10.1039/c6sc02343f.
Повний текст джерелаАнотація:
Thermal treatment of a 1:1 adduct of phosphorus tribromide and 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) results in the formation of a reduced phosphorus-containing dimer, which can be employed to access a range of low oxidation state compounds.
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Ellis, Bobby D., and Charles L. B. Macdonald. "Phosphorus(I) Iodide: A Versatile Metathesis Reagent for the Synthesis of Low Oxidation State Phosphorus Compounds." Inorganic Chemistry 45, no. 17 (August 2006): 6864–74. http://dx.doi.org/10.1021/ic060186o.
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Goswami, Tejasbharthi Pravinbharthi, Apeksha Kadam, and Rajashree Mashru. "New Smartphone Based Colorimetric Method Development and Validation of Drugs Containing Nitrogen, Phosphorus and Sulphur." Journal of Drug Delivery and Therapeutics 12, no. 3-S (June 15, 2022): 51–63. http://dx.doi.org/10.22270/jddt.v12i3-s.5503.
Повний текст джерелаАнотація:
Colorimetry is a method for determining the concentration of coloured substances in a solution. The intensity of colour is directly proportional to the concentration of compound being measured. Smartphone based colorimetry has grown in popularity as analytical instruments due to their low cost and ability to collect, store and process data all in one device. In smartphone colorimetry, the camera on the phone serves as a detector. The colorimetric method based on a smartphone and the UV method both are based on the detection of colour intensity. The ammonium metavanadate is having different oxidation states and it produce different colours in its oxidation state. The +5-oxidation state shows yellow colour, +4 oxidation state shows blue colour, +3 oxidation state shows green colour and +2 oxidation state shows purple colour. The ammonium metavanadate reagent is orange red in colour; however, it transforms into green colour complex when it reacts with drugs containing nitrogen, phosphorus and sulphur in its structure. In this article the developed method for all the drugs exhibits good linearity having Correlation coefficient about 0.998(Amoxicillin trihydrate), 0.998 (Silodosin) and for 0.999(Sofosbuvir). With increasing the concentrations of API, the colour intensity increases. All photographs were taken with smartphone and analysed using the photometrix PRO software. This application converts an image to an RGB histogram and regression models are included into the photometrix PRO application. By using Photometrix PRO and UV technique, the percent RSD of for all the three drugs was Using statistical tool i.e two paired test on both procedures for all the three different drugs, the results show that both are equally significant.
Keywords: UV spectrophotometry, Smartphone based colorimetry, Photometrix PRO, RGB Histogram
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Springett, Roger, Marzena Wylezinska, Ernest B. Cady, Mark Cope, and David T. Delpy. "Oxygen Dependency of Cerebral Oxidative Phosphorylation in Newborn Piglets." Journal of Cerebral Blood Flow & Metabolism 20, no. 2 (February 2000): 280–89. http://dx.doi.org/10.1097/00004647-200002000-00009.
Повний текст джерелаАнотація:
Changes in hemoglobin oxygenation and oxidation state of the CuA centre of cytochrome oxidase were measured with full spectral near infrared spectroscopy simultaneously with phosphorus metabolites using nuclear magnetic resonance 31P spectroscopy at high time resolution (10 seconds) during transient anoxia (FiO2 = 0.0 for 105 seconds) in the newborn piglet brain. During the onset of anoxia, there was no change in either phosphocreatine (PCr) concentration or the oxidation state of the CuA centre of cytochrome oxidase until there was a substantial fall in cerebral hemoglobin oxygenation, at which point the CuA centre reduced simultaneously with the decline in PCr. At a later time during the anoxia, intracellular pH decreased rapidly, consistent with a fall in cerebral metabolic rate for O2 and reduced flux through the tricarboxylic acid cycle. The simultaneous reduction of CuA and decline in PCr can be explained in terms of the effects of the falling mitochondrial electrochemical potential. From these observations, it is concluded that, at normoxia, oxidative phosphorylation and the oxidation state of the components of the electron transport chain are independent of cerebral oxygenation and that the reduction in the CuA signal occurs when oxygen tension limits the capacity of oxidative phosphorylation to maintain the phosphorylation potential.
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Hunt, P. G., and M. E. Poach. "State of the art for animal wastewater treatment in constructed wetlands." Water Science and Technology 44, no. 11-12 (December 1, 2001): 19–25. http://dx.doi.org/10.2166/wst.2001.0805.
Повний текст джерелаАнотація:
Although confined animal production generates enormous per-unit-area quantities of waste, wastewater from dairy and swine operations has been successfully treated in constructed wetlands. However, solids removal prior to wetland treatment is essential for long-term functionality. Plants are an integral part of wetlands; cattails and bulrushes are commonly used in constructed wetlands for nutrient uptake, surface area, and oxygen transport to sediment. Improved oxidation and nitrification may also be obtained by the use of the open water of marsh-pond-marsh designed wetlands. Wetlands normally have sufficient denitrifying population to produce enzymes, carbon to provide microbial energy, and anaerobic conditions to promote denitrification. However, the anaerobic conditions of wetland sediments limit the rate of nitrification. Thus, denitrification of animal wastewaters in wetlands is generally nitrate-limited. Wetlands are also helpful in reducing pathogen microorganisms. On the other hand, phosphorus removal is somewhat limited by the anaerobic conditions of wetlands. Therefore, when very high mass removals of nitrogen and phosphorus are required, pre- or in-wetland procedures that promote oxidation are needed to increase treatment efficiency. Such procedures offer potential for enhanced constructed wetland treatment of animal wastewater.
Дисертації з теми "Phosphorus oxidation state"
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Marriott, Katie Elizabeth Rose. "Reduced oxidation state phosphorus in prebiotic chemistry." Thesis, University of Leeds, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590306.
Повний текст джерелаАнотація:
This thesis analyses two different yet related chemical systems, both compatible with putative early earth geological environments, which could have readily and rapidly led to structurally complex molecules under mild, anaerobic aqueous conditions. In the first system, we report an example of the selective reactivity of H-phosphinic acid towards carbonyls which leads to interesting molecular architectures, some having structural motifs reminiscent of those in phosphor-sugars. The second system is based on H-phosphonic acid and its potential to be converted to condensed P-oxyacids which may have had some functional value within prebiotic environments. Chapter 2 outlines the reaction between H-phosphinic acid and pyruvic acid, and the various products that are produced under different environments, such as in the presence of metal ions, organics and at different pH. Chapter 3 discusses the structure of trieth-3 and compares the similarities with RNA. Molecular modelling using X-ray data of trieth-3 is used to evaluate the stability of it's structure in aqueous solution. The reaction between H-phosphinic acid and other prebiotically relelvant ketones is also described. Chapter 4 outlines the formation of pyrophosphite and its use as a possible prebiotic , phosphonylating agent. Chapter 5 outlines the reactions between glycerol and fatty acids and pyrophosphite as phosphonylating agent for this system. Chapter 6 discusses the use of ice eutectic conditions to investigate some of the reactions above at low concentrations.
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Hanks, John Richard. "Low oxidation state compounds of the group 4 and lanthanide metals with phosphorus containing aromatic ring systems." Thesis, University of Sussex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367767.
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Gossiaux, Alexandre. "Comportement au feu de mousses polyuréthanes rigides : Approches systématiques." Electronic Thesis or Diss., Centrale Lille Institut, 2021. http://www.theses.fr/2021CLIL0021.
Повний текст джерелаАнотація:
Une prise de conscience commune des facteurs environnementaux et plus particulièrement du réchauffement climatique rend urgent un meilleur contrôle de la consommation d'énergie. Une solution consiste à réduire les pertes d'énergie dans les bâtiments en utilisant de nouveaux matériaux d'isolation thermique efficaces tels que les mousses polyuréthanes. Ces mousses sont des matériaux très performants et compétitifs au regard des autres solutions existantes. Cependant, elles sont extrêmement inflammables en raison de leur nature organique. Les chercheurs et industrielles ajoutent alors des molécules appelées retardateurs de flamme (RFs) dans leur composition afin d’éviter le départ d’un incendie ou encore de diminuer l’intensité de la combustion lorsqu’un feu se déclare. C’est dans ce cadre que s’inscrit cette thèse dont l’objectif est d’étudier de manière systématique des mousses polyuréthanes (PUR) et polyisocyanurates (PIR). Le but est de proposer une démarche scientifique permettant un développement plus rapide et plus efficace de nouvelles formulations. Cette étude systématique a également été couplée à une étude multi-échelle du comportement au feu des mousses puisqu’un test à l’échelle du laboratoire a été développé: « le mini-SBI ». Les RFs étudiés dans ces travaux sont les RFs organiques phosphorés qui sont actuellement mis en avant afin de remplacer certains RFs halogénés qui pourraient être dangereux pour l’environnement et la santé. Les mécanismes de décomposition des mousses vierges et ignifugées ont été élucidés. Ainsi, dans le cas des RFs phosphorés, nous avons pu démontrer que leur mode d’action variait en fonction du degré d’oxydation du phosphore ainsi qu’en fonction de leur point de décomposition. De plus, l’efficacité des RFs varie également en fonction de la mousse utilisée (PUR ou PIR). Ces résultats pourront être mis à profit dans le développement de nouvelles formulationsA common awareness of environmental factors and more particularly of global warming makes it urgent to better control energy consumption. One solution is to reduce energy loss in building using new and efficient thermal insulation materials such as polymeric foams. Polyurethane (PUR) and polyisocyanurate (PIR) foams are very effective and competitive materials due to their low cost. However, these materials are extremely flammable due to their organic nature. Researchers and manufacturers add molecules called flame retardants (FRs) to their composition in order to prevent the outbreak of a fire or reduce the intensity of combustion when a fire breaks out. The objective of this PhD work is to study by systematic approaches the fire behavior of PUR and PIR foams. The aim is to propose a scientific approach allowing a quicker and more efficient development of new formulations. This systematic study was also coupled with a multi-scale study of the fire behavior of the foams, as a laboratory-scale fire test was developed (M-SBI), which allowed a quick and efficient examination of the formulations. The FRs studied in this work are phosphorus organic FRs which are currently promoted to replace some halogenated FRs which could be dangerous for the environment and health. The mechanisms of degradation of virgin and flame retarded foams were elucidated using various analytical tools. Thus, in the case of phosphorus FRs, we were able to demonstrate that their mode of action varied according to the phosphorus oxidation degree as well as according to their point of decomposition. Moreover, the efficiency of the FRs also varies according to the foam used (PUR or PIR). All these results can thus advantageously be exploited to propose future efficient flame retardants for specific systems to reduce the combustion intensity of the foams
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Masakapalli, Shyam Kumar. "Network flux analysis of central metabolism in plants." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:ac8b3836-9ab7-4060-b50a-df8aaa0e4ba5.
Повний текст джерелаАнотація:
The aim of this thesis was to develop stable-isotope steady-state metabolic flux analysis (MFA) based on 13C labeling to quantify intracellular fluxes of central carbon metabolism in plants. The experiments focus on the analysis of a heterotrophic cell suspension culture of Arabidopsis thaliana (L) Heynh. (ecotype Landsberg erecta). The first objective was to develop a robust methodology based on combining high quality steady-state stable labeling data, metabolic modeling and computational analysis. A comprehensive analysis of the factors that influence the outcome of MFA was undertaken and best practice established. This allowed a critical analysis of the subcellular compartmentation of carbohydrate oxidation in the cell culture. The second objective was to apply the methodology to nutritional perturbations of the cell suspension. A comparison of growth on different nitrogen sources revealed that transfer to an ammonium-free medium: (i) increased flux through the oxidative pentose phosphate pathway (oxPPP) by 10% relative to glucose utilisation; (ii) caused a substantial decrease in entry of carbon into the tricarboxylic acid cycle (TCA); and (iii) increased the carbon conversion efficiency from 55% to 69%. Although growth on nitrate alone might be expected to increase the demand for reductant, the cells responded by decreasing the assimilation of inorganic N. Cells were also grown in media containing different levels of inorganic phosphate (Pi). Comparison of the flux maps showed that decreasing Pi availability: (i) decreased flux through the oxPPP; (ii) increased the proportion of substrate fully oxidised by the TCA cycle; and (iii) decreased carbon conversion efficiency. These changes are consistent with redirection of metabolism away from biosynthesis towards cell maintenance as Pi is depleted. Although published genome-wide transcriptomic and metabolomic studies suggest that Pi starvation leads to the restructuring of carbon and nitrogen metabolism, the current analysis suggests that the impact on metabolic organisation is much less extreme.
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Bouchikhi, Benachir. "Propriétés physiques des structures métal/isolant/semiconducteur réalisées sur INP(N) à l'aide d'un oxyde natif plasma." Nancy 1, 1988. http://www.theses.fr/1988NAN10085.
Повний текст джерелаАнотація:
On aborde 3 aspects : la passivation du phosphorure d'indium dans un plasma RF d'oxygène, la caractérisation électrique des structures MIS élaborées à l'aide des mesures (C-V), (G-V) et d'autres mesures de spectrométries de niveaux profonds (DLTS-DDLTS), et l'élaboration du schéma équivalent de la structure MIS
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Sen, Sakya Singha. "Preparation and Reactions of Compounds with Heavier Group 14 Elements in Low Oxidation States." Doctoral thesis, 2010. http://hdl.handle.net/11858/00-1735-0000-0006-B088-7.
Повний текст джерелаЧастини книг з теми "Phosphorus oxidation state"
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Ellis, Bobby D., and Charles L. B. Macdonald. "Cationic Low Oxidation State Phosphorus and Arsenic Compounds." In ACS Symposium Series, 108–21. Washington, DC: American Chemical Society, 2005. http://dx.doi.org/10.1021/bk-2005-0917.ch008.
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Voroshylova, Natalia, and Nelia Melnikova. "ACID-ALKALINE STATE OF THE ORGANISM AS A REGULATOR OF THE MINERAL STATUS OF RATS’ BLOOD AT CADMIUM POISONING." In Integration of traditional and innovation processes of development of modern science. Publishing House “Baltija Publishing”, 2020. http://dx.doi.org/10.30525/978-9934-26-021-6-29.
Повний текст джерелаАнотація:
The work is devoted to the study of the influence of changes in the acid-base state on the indices of mineral metabolism in the body of cadmium sulphate-poisoned 6 months age-rats. It is known that the entry of cadmium salts into the body causes disorders of protein, lipid, carbohydrate, and mineral metabolism. As well-known, the endotoxicants affect cellular structures and activate lysosomal enzymes, block mitochondrial oxidation and ribosomal synthesis, initiate free radical processes, that are accompanied by disturbance of rheology and blood coagulation, micro- and macro-circulation, water-electrolyte balance. Such caused alterations in macro- and microelement composition of poisoned animals’ organisms disrupt the course of numerous metabolic processes. The research was conducted on the basis of the Department of Biochemistry and Vivarium of the National University of Life and Environmental Sciences of Ukraine using adult 6 months-age outbred rats breeding of the Research and Production Center of Laboratory Animal Husbandry of Educational and Scientific Institute of Veterinary Medicine and Quality and Safety of Livestock Products. Biological models of introduction of rats into the state of experimental metabolic acidosis and alkalosis before and after cadmium sulphate poisoning have been developed, as well as indices of acid-base status and mineral metabolism of the developed experimental models have been studied. The influence of the changes of parameters of acid-base state of the body on the content in the blood of poisoned rats of macronutrients (sodium, potassium, calcium, magnesium, inorganic phosphorus) and trace elements (copper, zinc, and iron). At compare of the changes in parameters of acid-base status of the blood of cadmium sulfate-poisoned animals, it was noted that the state of experimental metabolic acidosis is more expressed than alkalosis, that is more effective for correction and normalization of mineral metabolism in poisoned rats.
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Schweitzer, George K., and Lester L. Pesterfield. "The Nitrogen Group." In The Aqueous Chemistry of the Elements. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780195393354.003.0011.
Повний текст джерелаАнотація:
The Nitrogen Group of the Periodic Table contains the elements nitrogen N, phosphorus P, arsenic As, antimony Sb, and bismuth Bi. The outer electron structure ns2np3 characterizes all five of the elements, with n representing principal quantum numbers 2, 3, 4, 5, and 6, respectively. The ns2np3 indicates the possibility of oxidation states V, III, and -III. As one goes down the group, the metallic character increases, with N and P being distinctly non-metals, As a metalloid, and Sb and Bi metals. However, the major bonding in most of the compounds of the group is covalent, aqueous cationic species being formed only by Sb and Bi. A covalency of 5 is exhibited by all the elements except N, this being assignable to the considerable energy required to place 10 electrons around the atom. The pentavalent state is the most stable for P, with its stability falling off down the group, as the trivalent state stability increases. Covalent radii in pm are as follows: N (75), P (110), As(122), and Sb(143). Ionic radii (most hypothetical) in pm are these: Sb+3 (90), Sb+5 (74), Bi+3 (117), and Bi+5 (90). a. E–pH diagram. Figure 9.1 depicts the E–pH diagram for N with the soluble species (except H+) at 10−1.0 M. Equations for the lines that separate the species are displayed in the legend. The colorless strong acid nitric acid HNO3, its colorless anion nitrate NO3−, the colorless weak acid nitrous acid HNO2, its colorless anion NO2−, the colorless ammonium ion NH4+, and the colorless hypothetical compound ammonium hydroxide NH4OH are involved.
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Lambert, Tristan H. "C–O Ring Construction: The Martín and Martín Synthesis of Teurilene." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0043.
Повний текст джерелаАнотація:
Benjamin List at the Max-Planck-Institute in Mülheim reported (Angew. Chem. Int. Ed. 2013, 52, 3490) that the chiral phosphoric acid TRIP catalyzed the asymmetric SN2-type intramolecular etherification of 1 to produce tetrahydrofuran 2 with a selectivity factor of 82. The coupling of alkenol 3 with 4 to give the α-arylated tetrahydropyran 5 via a method that combined gold catalysis and photoredox catalysis was disclosed (J. Am. Chem. Soc. 2013, 135, 5505) by Frank Glorius at Westfälische Wilhelms-Universität Münster. Mark Lautens at the University of Toronto reported (Org. Lett. 2013, 15, 1148) the conversion of cyclohexanedione 6 and phenylboronic acid to bicyclic ether 8 using rhodium catalysis in the presence of dienyl ligand 7. Propargylic ether 9 was found (Org. Lett. 2013, 15, 2926) by John P. Wolfe at the University of Michigan to undergo conversion to furanone 10 upon treatment with dibutylboron triflate and Hünig’s base followed by oxidation with hydrogen peroxide. Tomislav Rovis at Colorado State University demonstrated (Chem. Sci. 2013, 4, 1668) that the spirocyclic compound 13 could be prepared in enantioenriched form from 11 by a photoisomerization- coupled Stetter reaction using carbene catalyst 12. Antonio C. B. Burtoloso at the University of São Paulo reported (Org. Lett. 2013, 15, 2434) the conversion of ketone 14 to lactone 15 using samarium(II) iodide and methyl acrylate. The merger of diketone 16 and pyrone 17 in the presence of Amberlyst-15 to produce (−)- tenuipyrone 18 was disclosed (Org. Lett. 2013, 15, 6) by Rongbiao Tong at the Hong Kong University of Science and Technology. Joanne E. Harvey at Victoria University of Wellington in New Zealand found (Org. Lett. 2013, 15, 2430) that tricyclic ether 20 could be generated efficiently from dihydropyran 19 and pyrone 17 via a palladium-catalyzed double allylic alkylation cascade. Two rings and four stereocenters were generated in the construction of bicyclic ether 23 from dienol 21 and acetal 22 via a Lewis acid-mediated cascade, as reported (Org. Lett. 2013, 15, 2046) by Christine L. Willis at the University of Bristol.
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Lambert, Tristan H. "Construction of Stereochemical Arrays." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0045.
Повний текст джерелаАнотація:
The unprecedented enantioselective 1,8-addition of azlactone 1 to acylpyrrole 2 catalyzed by triaminophosphorane 3 was reported (J. Am. Chem. Soc. 2012, 134, 19370) by Takashi Ooi at Nagoya University. Tomislav Rovis at Colorado State University developed (Angew. Chem. Int. Ed. 2012, 51, 12330) the asymmetric oxidative hetero-Diels-Alder reaction of propionaldehyde (5) and ketone 6 to produce lactone 8, catalyzed by NHC catalyst 7 in the presence of phenazine. A related NHC catalyst 11 was utilized (Angew. Chem. Int. Ed. 2012, 51, 8276) by Xue-Wei Liu at Nanyang Technological University for the homoenolate addition of enal 9 to nitrodiene 10 to furnish 12 with high ee. The vinylogous conjugate addition of butenolide 13 to 15 to produce 16 with exquisite stereoselectivity was accomplished (Angew. Chem. Int. Ed. 2012, 51, 10069) by Kuo-Wei Huang at KAUST, Choon-Hong Tan at Henan University and Nanyang Technological University, and Zhiyong Jiang at Henan University. The enantioselective production of lactone 18 was achieved (J. Am. Chem. Soc. 2012, 134, 20197) by Jeffrey S. Johnson at the University of North Carolina at Chapel Hill by dynamic kinetic resolution (DKR) of α-keto ester 17. A related DKR strategy was employed (Org. Lett. 2012, 14, 6334) by Brinton Seashore-Ludlow at the KTH Royal Institute of Technology and Peter Somfai at Lund University in Sweden and the University of Tartu in Estonia for hydrogenation of α-amino-β-ketoester 19 to furnish aminoalcohol 21 with high Shigeki Matsunaga and Motomu Kanai at the University of Tokyo developed (Angew. Chem. Int. Ed. 2012, 51, 10275) a unique strategy for the selective production of the cross-aldol adduct 24 by in situ generation of an aldehyde enolate from allyloxyborane 23 under rhodium catalysis. The highly diastereoselective construction of adduct 26 bearing two adjacent quaternary stereocenters by ketone allylation with allyl sulfide 25 was reported (Angew. Chem. Int. Ed. 2012, 51, 7263) by Takeshi Takeda at the Tokyo University of Agriculture and Technology. Wen-Hao Hu at East China Normal University reported (Nature Chem. 2012, 4, 733) the enantioselective three-component coupling of diazoester 27, N-benzylindole (28), and imine 29 to furnish 31 under the action of Rh2(OAc)4 and phosphoric acid 30.
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E. Khrulev, Alexey, Irina V. Belova, Irina V. Soloveva, Anna G. Tochilina, Natalya A. Shiyanova, Anastasiya A. Nikitina, and Natalya S. Khruleva. "Specific Cerebrovascular Risk Factors, Colon Microbiocenosis and Its Correction in Patients Receiving Long-Term Programmed Hemodialysis." In Multidisciplinary Experiences in Renal Replacement Therapy. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101300.
Повний текст джерелаАнотація:
Introduction: The problem of acute and chronic cerebrovascular disorders in dialysis patients remains the most urgent. Risk factors for cerebrovascular diseases in CKD and dialysis patients can be conditionally divided into “traditional” (arterial hypertension, diabetes mellitus, hypercholesterolemia) and “specific” (associated with renal pathology and dialysis procedures). The spectrum of specific factors of cerebrovascular risk in patients with dialysis stage of the CKD includes specific dialysis factors that form during programmed HD, as well as impaired phosphorus-calcium metabolism and calcification of the arterial microvasculature, increased blood levels of β2-microglobulin, homocysteine, malondialdehyde and superoxide dismutase, a decrease in the level of nitric oxide (II) metabolites, development of nephrogenic anemia and dysfunction of blood cells, malnutrition and dietary features of patients with renal pathology, accumulation of uremic toxins and toxins of intestinal bacteria, etc. Opportunistic gut microorganisms can produce uremic toxins, which are associated with an increased risk of inflammation, increased oxidative stress, and a higher risk of cardiovascular disease (CVD). Description of the spectrum of risk factors for cerebrovascular pathology in dialysis patients and effective control over them seems to be an effective strategy aimed at increasing the duration and quality of life in patients receiving renal replacement therapy. The aim of the investigation was to study the species composition of colon microbiocenosis in patients with CKD receiving programmed HD treatment and to evaluate the effectiveness of its correction using a new immobilized synbiotic. Materials and methods: Samples of colon microbiota from 62 patients undergoing programmed hemodialysis were studied before and after a course of diet therapy that included probiotic components, in particular, the immobilized synbiotic LB-complex L. Isolation of microorganisms was carried out according to our original method; for bacteria identification, a MALDI-TOF Autoflex speed mass spectrometer (Bruker Daltonik, Germany) was used in the Biotyper program mode. The results were assessed using the criteria proposed by the authors and based on the OST 91500.11.0004-2003. The efficacy of the immobilized synbiotic was determined based on the clinical data, questionnaires, and bacteriological tests. Results: In patients receiving programmed hemodialysis (before the start of the diet therapy), chronic moderate inflammation and azotemia were found. Dysbiotic changes in microbiocenosis were revealed in all the examined patients; in the absence or suppression of lacto- and bifidoflora, the number and diversity of Bacteroides spp., Clostridium spp., Collinsella spp., Eggerthella spp. and other bacteria increased, which was consistent with the theory of functional redundancy of gut microbiota. From the answers to the questionnaires, a decrease in the quality of life was found (up to 70 points out of 100) according to six of the eight scales used. After the combined therapy using the synbiotic LB-complex L in the study group, 56% of the examined patients showed their microbiocenosis restored to normal; no grade III dysbiosis was detected in any patient. There was a significant decrease in CRP and ESR in these patients and an improvement in the quality of life by criteria reflecting physical health. Conclusion: Acute/chronic CVD in patients with CKD of the pre-dialysis and dialysis periods are the most frequent and formidable complications. The spectrum of “traditional” and “specific” CV risk factors in dialysis patients will be described in the chapter. Special attention will be paid to the intestinal microbiota and opportunistic intestinal microorganisms. The aim was to study the species composition of colon microbiocenosis in HD patients, and to evaluate the effectiveness of its correction using a new immobilized synbiotic. Materials and Methods. Samples of colon microbiota from 62 HD patients were studied before/after a course of diet therapy that included probiotic components, the immobilized synbiotic LB-complex L. MALDI-TOF Autoflex speed mass spectrometer was used in the Biotyper program mode. The efficacy of the immobilized synbiotic was determined based on the clinical data, questionnaires, and bacteriological tests. Results. Dysbiotic changes in microbiocenosis were revealed in all patients; in the absence/suppression of lacto-and bifidoflora, the number and diversity of Bacteroides spp.,Clostridium spp.,Collinsella spp.,Eggerthella spp. and other bacteria increased. After the combined therapy using the synbiotic LB-complex L in the study group, 56% of the examined patients showed their microbiocenosis restored to normal; no grade III dysbiosis was detected in any patient.