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121.
Bhattacharyya Suvanjan Pathak Manabendra Sharifpur Mohsen Chamoli Sunil Ewim Daniel R. E. 《Journal of Thermal Analysis and Calorimetry》2021,145(3):1019-1034
Journal of Thermal Analysis and Calorimetry - The effects of perforated circular disc swirl generator on heat transfer (HT) and flow fields in a solar air heater helical corrugated tube have been... 相似文献
122.
123.
Takashi Uneyama Yuichi Masubuchi Kazushi Horio Yumi Matsumiya Hiroshi Watanabe Jai A. Pathak C. Michael Roland 《Journal of Polymer Science.Polymer Physics》2009,47(11):1039-1057
For type‐A polymer chains having type‐A dipoles parallel along the chain backbone (such as cis‐polyisoprene), a theoretical analysis was conducted for the rheodielectric response to relate this response to the chain dynamics. The rheodielectric response in the shear gradient direction (y direction) under steady shear was analyzed on the basis of a Langevin equation. It turned out that the relaxation time is exactly the same for the rheodielectric relaxation function and the end‐to‐end vector autocorrelation function defined in the shear gradient direction and that the relaxation mode distribution also coincides for these functions at least up to second order of the shear rate (corresponding to the lowest order of nonlinearities of these functions). Consequently, the Green‐Kubo theorem holds satisfactorily, and the rheodielectric intensity is proportional to the squared chain size in y direction, 〈R〉, averaged over the time‐independent conformational distribution function under steady shear. The situation is more complicated under large amplitude oscillatory strain (LAOS) because the conformational distribution function fLAOS is synchronized with LAOS to oscillate at the LAOS frequency, Ω. The rheodielectric response under LAOS was found to detect this oscillation of fLAOS being coupled with the oscillation of the electric field, E(t) = E0sin ωt, and thus, split into a series of components oscillating at frequencies ω and ω ± βΩ (β = 1, 2, …). Consequently, the rheodielectric intensity under LAOS, evaluated from the component oscillating at ω, is no longer proportional to 〈R〉. However, the relative mode distribution and relaxation time of this component can be directly related to those of the end‐to‐end vector correlation averaged over a nonoscillatory part of fLAOS. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1039–1057, 2009 相似文献
124.
Biswarup Pathak Devleena Samanta Prof. Dr. Rajeev Ahuja Prof. Dr. Purusottam Jena 《Chemphyschem》2011,12(13):2423-2428
Super‐ and hyperhalogens are a class of highly electronegative species whose electron affinities far exceed those of halogen atoms and are important to the chemical industry as oxidizing agents, biocatalysts, and building blocks of salts. Using the well‐known Wade–Mingos rule for describing the stability of closo‐boranes BnHn2? and state‐of‐the‐art theoretical methods, we show that a new class of super‐ and hyperhalogens, guided by this rule, can be formed by tailoring the size and composition of borane derivatives. Unlike conventional superhalogens, in which a central metal atom is surrounded by halogen atoms, the superhalogens formed according to the Wade–Mingos rule do not have to have either halogen or metal atoms. We demonstrate this by using B12H13 and its isoelectronic cluster CB11H12 as examples. We also show that while conventional superhalogens containing alkali atoms require at least two halogen atoms, a single borane‐like moiety is sufficient to give M(B12H12) clusters (M=Li, Na, K, Rb, Cs) superhalogen properties. In addition, hyperhalogens can be formed by using the above superhalogens as building blocks. Examples include M(B12H13)2 and M(CB11H12)2 (M=Li–Cs). This finding opens the door to an untapped source of superhalogens and weakly coordinating anions with potential applications. 相似文献
125.
Novel 7‐Nitro‐1‐(Piperidin‐4‐yl)‐4,5‐Dihydro‐[1,2,4] Triazolo[4,3‐a]Quinoline‐Sulphonamide Derivatives as Antimicrobial Agents: Design,Synthesis, and Bio‐Activity 下载免费PDF全文
Bijivemula N. Reddy Peddiahgari Vasu Govardhana Reddy Bhoomireddy Rajendra Prasad Reddy Sirigi Reddy Sudharsan Reddy S. M. Reddy Madhvesh Pathak 《Journal of heterocyclic chemistry》2016,53(5):1416-1423
In attempt to search for more potent antimicrobial agents, a series of 7‐nitro‐1‐(piperidin‐4‐yl)‐4,5‐dihydro‐[1,2,4]triazolo[4,3‐a]quinoline‐derived sulphonamides were synthesized. Their structures were established by elemental analyses, IR, and NMR (1H and 13C) spectral data. The antibacterial activity of the obtained compounds was investigated against different Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) and Gram‐positive (Bacillus subtilis and Staphylococcus aureus) bacteria and antifungal activity against two fungal strains (Aspergillus niger and Aspergillus clavatus) using disk diffusion method at various concentrations (20, 40, 60, and 80 μg/mL). The study reveals that most of the title compounds showed significant antibacterial and fungal activity when compared with their respective standards streptomycin and griseofulvin. 相似文献
126.
Dibyendu Dana Tuhin Das Athena Choi Ashif I. Bhuiyan Tirtha K. Das Tanaji T. Talele Sanjai K. Pathak 《Molecules (Basel, Switzerland)》2022,27(2)
Cell cycle kinases represent an important component of the cell machinery that controls signal transduction involved in cell proliferation, growth, and differentiation. Nek2 is a mitotic Ser/Thr kinase that localizes predominantly to centrosomes and kinetochores and orchestrates centrosome disjunction and faithful chromosomal segregation. Its activity is tightly regulated during the cell cycle with the help of other kinases and phosphatases and via proteasomal degradation. Increased levels of Nek2 kinase can promote centrosome amplification (CA), mitotic defects, chromosome instability (CIN), tumor growth, and cancer metastasis. While it remains a highly attractive target for the development of anti-cancer therapeutics, several new roles of the Nek2 enzyme have recently emerged: these include drug resistance, bone, ciliopathies, immune and kidney diseases, and parasitic diseases such as malaria. Therefore, Nek2 is at the interface of multiple cellular processes and can influence numerous cellular signaling networks. Herein, we provide a critical overview of Nek2 kinase biology and discuss the signaling roles it plays in both normal and diseased human physiology. While the majority of research efforts over the last two decades have focused on the roles of Nek2 kinase in tumor development and cancer metastasis, the signaling mechanisms involving the key players associated with several other notable human diseases are highlighted here. We summarize the efforts made so far to develop Nek2 inhibitory small molecules, illustrate their action modalities, and provide our opinion on the future of Nek2-targeted therapeutics. It is anticipated that the functional inhibition of Nek2 kinase will be a key strategy going forward in drug development, with applications across multiple human diseases. 相似文献
127.
Murli Manohar Verma Shankar Dayal Pathak 《International Journal of Theoretical Physics》2012,51(8):2370-2379
We investigate the tachyonic cosmological potential V(?) in two different cases of the quasi-exponential expansion of universe and discuss various forms of interaction between the two components—matter and the cosmological constant—of the tachyonic scalar field, which lead to the viable solutions of their respective energy densities. The distinction among the interaction forms is shown to appear in the O m (x) diagnostic. Further, the role of the high- and low-redshift observations of the Hubble parameter is discussed to determine the proportionality constants and hence the correct form of matter–cosmological constant interaction. 相似文献
128.
Kishore Thapliyal Subhashish Banerjee Anirban Pathak S. Omkar V. Ravishankar 《Annals of Physics》2015
We study nonclassical features in a number of spin-qubit systems including single, two and three qubit states, as well as an N qubit Dicke model and a spin-1 system, of importance in the fields of quantum optics and information. This is done by analyzing the behavior of the well known Wigner, P, and Q quasiprobability distributions on them. We also discuss the not so well known F function and specify its relation to the Wigner function. Here we provide a comprehensive analysis of quasiprobability distributions for spin-qubit systems under general open system effects, including both pure dephasing as well as dissipation. This makes it relevant from the perspective of experimental implementation. 相似文献
129.
Kulkarni AD Rai D Bartolotti LJ Pathak RK 《The journal of physical chemistry. A》2006,110(42):11855-11861
The present article comprises a theoretical study of structures and energetics of the lowest energy conformers of peroxyformic acid (PFA) and its hydrated variants, viz. PFA...(H2O)n (n = 1-4), at the molecular level. We have employed two different ab initio quantum chemical methods, viz. restricted Hartree-Fock (RHF) and the second-order M?ller-Plesset (MP2) perturbation theory with the basis sets 6-31G(d,p) and 6-311++G(2d,2p). Modifications in the structure as well as vibrational frequencies of PFA brought about by successive addition of H2O molecules are also discussed. Cooperativity of hydrogen bonding in these clusters can be gauged through a detailed many body interaction energy analysis. 相似文献
130.
S. Biswas P. N. Pathak D. K. Singh S. B. Roy V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(1):13-19
The extraction of uranium(VI) from nitric acid medium is investigated using 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl
ester (PC88A in dimeric form, H2A2) as extractant either alone or in combination with neutral extractants such as tri-n-butyl phosphate (TBP), trioctyl phosphine oxide (TOPO), and dioctyl sulfoxide (DOSO). The effects of different experimental
parameters such as aqueous phase acidity (up to 10 M HNO3), nature of diluent [xylene, carbon tetrachloride (CCl4), n-dodecane and methyl iso-butyl ketone (MIBK)] and of temperature (303–333 K) on the extraction behavior of uranium were investigated. Synergistic
extraction of uranium was observed between 0.5 and 6 M HNO3. Use of MIBK as diluent was also studied. Temperature variation studies using PC88A as extractant showed exothermic nature
of extraction process. Studies were carried out to optimize the conditions for the recovery of uranium from the raffinate
generated during the purification of uranium from nitric acid medium. Inductively Couple Plasma Atomic Emission Spectroscopy
(ICP-AES) and Energy Dispersive X-Ray Fluorescence (EDXRF) techniques were employed for analysis of uranium in equilibrated
samples. 相似文献