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排序方式: 共有238条查询结果,搜索用时 265 毫秒
151.
The electrochemical detection of dopaminergic agonist drug pramipexole dihydrochloride monohydrate (PPX) has been investigated by cyclic voltammetric (CV) and amperometric i–t techniques at functionalized multi-walled carbon nanotubes-modified glassy carbon electrode. For the first time, a sensitive and rapid electrochemical method was developed for the determination of PPX. The surface morphological characteristics of the proposed electrode have been studied by using transmission electron microscopy (TEM); further, electrochemical impedance spectroscopy (EIS) and Fourier transform infrared spectroscopy (FTIR) have been employed. PPX shows an irreversible anodic peak, which may be ascribed to the oxidation of the –NH groups of PPX. The proposed method was showing good sensitivity of 0.993 μA μM?1 cm?2 with a linear range of 5 to 340 μM by amperometric i–t and CV technique shows a linear range of 12.5 to 313 μM with a sensitivity of 1.92 μA μM?1 cm?2. The recovery of PPX from blood serum samples was found 100.6 and 98.9 %, respectively. Furthermore, the proposed method has been demonstrated for the determination of PPX in commercially available pharmaceutical samples and good agreement of results obtained. 相似文献
152.
Bharadwaj R. Prabhala Mahesh V. Panchagnula Srikanth Vedantam 《Colloid and polymer science》2013,291(2):279-289
In this paper, we study equilibrium three-dimensional shapes of drops on hysteretic surfaces. We develop a function coupled with the publicly available surface energy minimization code Surface Evolver to handle contact angle hysteresis. The function incorporates a model for the mobility of the triple line into Surface Evolver. The only inputs to the model are the advancing and receding contact angles of the surface. We demonstrate this model’s versatility by studying three problems in which parts of the triple line advance while other parts either recede or remain stationary. The first problem focuses on the three-dimensional shape of a static pendant drop on a vertical surface. We predict the finite drop volume when impending sliding motion is observed. In the second problem, we examine the equilibrium shapes of coalescing sessile drops on hysteretic surfaces. Finally, we study coalescing puddles in which gravity plays a leading role in determining the equilibrium puddle shape along with hysteresis. 相似文献
153.
Dinne Naresh Kumar Reddy Kothapalli Bannoth Chandrasekhar Yaddanapudi Sesha Siva Ganesh Srikanth Sharathchandra Gorantla Siddabathuni Ramanjaneyulu K. Shiva Kumar 《合成通讯》2013,43(4):513-523
A greener approach for the synthesis of 3-arylmethyl/diarylmethyl indoles has been achieved via a PMA-SiO2-mediated three-component reaction (the aza-Friedel–Crafts reaction) involving indoles, aldehydes, and N,N-disubstituted anilines in PEG-400. A variety of indole derivatives were prepared by using this operationally simple and straightforward methodology in acceptable yields. 相似文献
154.
G. Srikanth D. V. N. Srinivas Rao P. Badarinadh Gupta P. Lavanya Aminul Islam 《合成通讯》2013,43(9):1359-1366
A new and efficient process through a new intermediate, (2E)-2-cyano-3-(3,4-dihydroxy-5-nirtrophenyl)prop-2-enoic acid 15, has been described for preparing substantially pure entacapone 1. This new intermediate 15 was prepared by Knoevenagel condensation of 3,4-dihydroxy-5-nitrobenzaldehyde 2 with 2-cyanoacetic acid 14 and was further condensed with diethylamine to get pure entacapone 1. Some of the important process-related impurities of entacapone (17, 18, 19, and 20) were also prepared easily from this intermediate 15. 相似文献
155.
‘Caging’ and ‘uncaging’ bioactive substrates are key techniques in studying a wide variety of biological processes. In the present study, two-types of novel caged glutamates with a two-photon absorption (TPA) core, that is, π-extended coumarin, were synthesized and their photochemical release of glutamate was analyzed. The high yields of glutamate (>92%) were observed in the photolysis of compounds 1 and 10, respectively. 相似文献
156.
Synthesis and Characterization of Donor–π‐Acceptor‐Based Porphyrin Sensitizers: Potential Application of Dye‐Sensitized Solar Cells
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Mareedu Sreenivasu Akira Suzuki Dr. Mitsuhiro Adachi Challuri Vijay Kumar Dr. Bingi Srikanth S. Rajendar Dasa Rambabu Dr. Rangaraju Satish Kumar P. Mallesham Dr. N. Vijaya Bhaskar Rao Dr. M. Suresh Kumar Dr. P. Y. Reddy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(43):14074-14083
New porphyrin sensitizers based on donor–π‐acceptor (D‐π‐A) approach have been designed, synthesized, characterized by various spectroscopic techniques and their photovoltaic properties explored. N,N′‐Diphenylamine acts as donor, the porphyrin is the π‐spacer, and either carboxylic acid or cyanoacryclic acid acts as acceptor. All compounds were characterized by using 1H NMR spectroscopy, ESI‐MS, UV–visible emission spectroscopies as well as electrochemical methods. The presence of aromatic groups between porphyrin π‐plane and acceptor group push the absorption of both Soret and Q‐bands of porphyrin towards the red region. The electrochemical properties suggests that LUMO of these sensitizers above the TiO2 conduction band. Finally, the device was fabricated using liquid redox electrolyte (I?/I3?) and its efficiency was compared with that of a leading sensitizer. 相似文献
157.
Large Magnetocaloric Effect,Moment, and Coercivity Enhancement after Coating Ni Nanoparticles with Ag
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Dr. Sanyadanam Srinath Dr. Pankaj Poddar Raja Das Dr. Deepti Sidhaye Dr. Bhagavatula Lakshmi Vara Prasad Dr. James Gass Prof. Hariharan Srikanth 《Chemphyschem》2014,15(8):1619-1623
We observe a large magnetocaloric effect in monodisperse Ni and NicoreAgshell nanoparticles in the superparamagnetic region. The organically passivated Ni nanospheres show a large magnetic entropy change of 0.9 J kg?1 K for a 3 T magnetic field change. In comparison to the surfactant‐coated Ni nanoparticles, the NicoreAgshell nanoparticles show an enhanced coercivity, magnetization, and magnetocaloric effect (1.3 kg K for a 3 T magnetic field change). The coercivity at 10 K increases from 360 Oe for Ni nanoparticles to nearly 610 Oe for NicoreAgshell particles. This large enhancement is attributed to the enhanced inter‐particle interaction, which is mediated by the metallic shell, over the relatively weaker dipolar interaction in the surfactant‐coated Ni nanoparticles, and to modification of the surface spin structure. 相似文献
158.
Chada Raji Reddy Guvvala Balakrishna Reddy Boinapally Srikanth 《Tetrahedron: Asymmetry》2011,22(18-19):1725-1728
The stereoselective synthesis of the unnatural enantiomer of a cyclic diarylheptanoid, diospongin A is described. The salient feature of this synthesis is the formation of a tetrahydropyran ring via the AgOTf-catalysed intramolecular oxa-Michael addition of a β-hydroxy ynone followed by hydrogenation 相似文献
159.
P. Poddar J. Gass D.J. Rebar S. Srinath H. Srikanth S.A. Morrison E.E. Carpenter 《Journal of magnetism and magnetic materials》2006
A comparative study of the magnetocaloric effect (MCE) is reported in two different types of chemically synthesized magnetic nanoparticle systems—cobalt ferrite and manganese zinc ferrite with mean size around 5 and 15 nm, respectively. While CoFe2O4 nanoparticles were synthesized using co-precipitation, the Mn0.68Zn0.25Fe2.07O4 (MZFO) nanoparticles were prepared by reverse micelle technique using AOT as surfactant. Our results indicate that the change in entropy with the change in applied magnetic field (dS/dH) is reasonably large for this class of nanoparticles and has a wide distribution over a broad temperature range covering the region above and below the blocking temperature. The maximum entropy change is influenced by the particle size, overall distribution in anisotropy and magnetic moments. 相似文献
160.
Songjun Li Srikanth Pilla Shaoqin Gong 《Journal of polymer science. Part A, Polymer chemistry》2009,47(9):2352-2360
Modulated molecular recognition was achieved in a temperature‐sensitive molecularly‐imprinted polymer. Using PNIPA as the temperature‐sensitive element, the adenine‐imprinted polymer (i.e., MIP‐S) was prepared and characterized. The MIP‐S exhibited a temperature‐responsive molecular recognition behavior because of the thermal phase‐transition within the MIP‐S network. Specifically, below the transition temperature (e.g., 20 °C), the MIP‐S showed a highly specific recognition for the imprint species (adenine). However, the MIP‐S did not show any significant resolution for the imprint species (adenine) and its analogue (1‐methyladenine) above the transition temperature (e.g., 40 °C). Such temperature‐regulated recognition is comparable to a switch‐on and switch‐off process, thereby making tunable molecular recognition feasible. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2352–2360, 2009 相似文献