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141.
The total synthesis of the 2,6-disubstituted piperidine alkaloid (?)-andrachcinidine is reported using Keck’s asymmetric allylation, Sharpless epoxidation, nucleophilic substitution, and intramolecular aza-Michael addition as the key steps. 相似文献
142.
A. D. Shinde R. Acharya A. V. R. Reddy 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1287-1292
The k0-based internal monostandard instrumental neutron activation analysis (IM-INAA) method was applied for quantification of trace impurities in seven high purity aluminum samples used as fuel cladding in a research reactor. Samples along with BCS CRM 182 (Si–Al alloy) were irradiated in high flux reactor neutrons for 10–15 h. In situ detection efficiency, needed in concentration calculation ratio by IM-INAA, was obtained using gamma rays of activation products produced in the samples. Elemental concentration ratios obtained with respect to Fe (used as internal monostandard) were converted to absolute concentrations by determining concentration of Fe by relative method of NAA. Concentrations of ten trace elements (Sc, Cr, Co, Zn, Ga, La, Ce, Sm, W and Hf) including major element Fe were determined in this work. The method used is non-destructive in nature and does not need multielement standards. Results of IM-INAA were compared with those obtained by relative method of INAA and inductively coupled plasma atomic emission spectrometry (ICP-AES). Details of methodologies and results obtained by all methods are discussed and compared in the paper. 相似文献
143.
Dr. A. Suresh Kumar Dr. Guguloth Thirupathi G. Surendra Reddy Prof. Dr. Dhevalapally B. Ramachary 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(5):1177-1183
An ideal stereoselective insertion of in situ generated benzynes into lawsones through domino formal [2+2]-cycloaddition followed by rearrangement is disclosed. The reaction allowed for the preparation of biologically important benzannulated bicyclo[3.3.0]octanes in good yields and with excellent selectivities by using simple substrates and conditions. 相似文献
144.
Time‐dependent finite element simulations of a shear‐thinning viscoelastic fluid with application to blood flow 下载免费PDF全文
A new finite element method is developed to simulate time‐dependent viscoelastic shear‐thinning flows characterized by the generalized Oldroyd‐B model. The focus of the algorithm is improved stability through a free‐energy dissipative scheme by using low‐order piecewise‐constant finite element approximations for stress. The algorithm is further modified by incorporating a pressure‐projection method, a DG‐upwinding scheme, a symmetric interior penalty DG method to solve the elliptic pressure‐update equation and a geometric multigrid preconditioner. The improved stability and cost to accuracy is compared when using higher order discontinuous bilinear approximation, where in addition, we consider the influence of a slope limiter for these elements. The algorithm is applied to the 2D start‐up‐driven cavity problem, and the stability of the free energy is illustrated and compared between element choices. An application of the model to modelling blood in small arterioles and channels is considered by simulating pulsatile blood flow through a stenotic arteriole. The individual influences of viscoelasticity and shear‐thinning within the generalized Oldroyd‐B model are investigated by comparing results to the Newtonian, generalized Newtonian and Oldroyd‐B models. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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146.
N‐bromo‐hydantoin grafted polystyrene beads: Synthesis and nano‐micro beads characteristics for achieving controlled release of active oxidative bromine and extended microbial inactivation efficiency 下载免费PDF全文
Mahran Daif Konda Reddy Kunduru Natalia Laout Stanislav Ratner Nurit Beyth Abraham J. Domb 《Journal of polymer science. Part A, Polymer chemistry》2016,54(5):596-610
N‐bromo‐hydantoin and N‐bromo‐5,5′‐dimethylhydantoin conjugated polystyrene beads were synthesized from chloromethyl polystyrene beads which differ in their particles size, crosslinking, nano‐micro porosity, and tunnels size on the surface, in order to study the effect of these parameters on oxidative halogen release and resultant activity, for water purification applications. The synthesized beads were characterized using elemental analysis, FT‐IR, solid state 13C‐NMR, and scanning electron microscope (SEM). The conjugation yield and kinetics in different solvents and bromine loading capacity were studied. The N‐bromoamine polystyrene beads were tested for water decontamination according to NSF 231 protocol. The release of active bromine was analyzed by spectrophotometer using a DPD‐1 kit and also studied the antimicrobial activity against Escherichia coli and MS2 phages. Bead's nano‐micro characteristics were found critical for oxidative halogen release control: rate stabilization and modulation, extension and also influences antimicrobial activity. The synthesized beads exhibited extended and stable release of bromine, 6 and 4 log reduction for E. coli and MS2, respectively for 250 L of passing contaminated water. Thus, N‐halamine hydantoins conjugated polystyrenes, chemically or kinetically release modified should have applications as disinfectants in water purification systems as well as medical field. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 596–610 相似文献
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148.
Anumula Rajini Muralasetti Nookaraju Ingala Ajit Kumar Reddy Venkatathri Narayanan 《Chemical Papers》2014,68(2):170-179
A novel vanadium dodecylamino phosphate was synthesised by an instant reaction between phosphoric acid and vanadyl acetylacetonoate using dodecylamine as the structure-directing agent at ambient temperature. The physicochemical characteristics of the material were investigated by a variety of analytical techniques. XRD studies revealed the presence of vanadium phosphate and hydrated vanadium phosphate phases in the framework of the material. The catalytic application of this material toward in the synthesis of polyhydroquinolines via Hantzsch condensation was investigated at ambient temperature. This method affords high yields within short reaction times. The influence of various reaction parameters such as different solvents, catalyst dosage, effect of aldehydes, and reusability was studied and a plausible mechanism proposed. 相似文献
149.
Rama Raju Baadhe Naveen Kumar Mekala Satwik Reddy Palagiri Sreenivasa Rao Parcha 《Applied biochemistry and biotechnology》2012,167(5):1172-1182
In this case study, we designed a farnesyl pyrophosphate (FPP) biosynthetic network using hybrid functional Petri net with extension (HFPNe) which is derived from traditional Petri net theory and allows easy modeling with graphical approach of various types of entities in the networks together. Our main objective is to improve the production of FPP in yeast, which is further converted to amorphadiene (AD), a precursor of artemisinin (antimalarial drug). Natively, mevalonate (MEV) pathway is present in yeast. Methyl erythritol phosphate pathways (MEP) are present only in higher plant plastids and eubacteria, but not present in yeast. IPP and DAMP are common isomeric intermediate in these two pathways, which immediately yields FPP. By integrating these two pathways in yeast, we augmented the FPP synthesis approximately two folds higher (431.16 U/pt) than in MEV pathway alone (259.91 U/pt) by using HFPNe technique. Further enhanced FPP levels converted to AD by amorphadiene synthase gene yielding 436.5 U/pt of AD which approximately two folds higher compared to the AD (258.5 U/pt) synthesized by MEV pathway exclusively. Simulation and validation processes performed using these models are reliable with identified biological information and data. 相似文献
150.
D. Bhaskar Reddy P. V. Ramana Reddy M. Muralidhar Reddy M. V. Ramana Reddy S. Vijayalakshmi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):325-329
Abstract Some new 1,1,2-trisubstituted ethylenic sulfones have been prepared by the condensation of aryl- and benzylsulfonylmethylsulfonylacetic acid esters with araldehydes. 相似文献