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Vaddi R.,Padmasri Dr Bv Raju Institute Of Technology | Agarwal R.P.,Shobhit University | Dasgupta S.,Indian Institute of Technology Roorkee
IEEE Transactions on Electron Devices | Year: 2012

In this brief, a new analytical model to compute the potential distribution in gate overlap and underlap regions of a generic double-gate (DG) MOSFET (valid for asymmetric features in front- and back-gate insulator thicknesses, gate bias, and gate work functions) for operation in the subthreshold condition is proposed. A closed form solution to 2-D Poisson's equation is obtained with approximation of parabolic potential function along vertical direction of the device. Conformal mapping technique is applied for modeling fringe electric field in the underlap regions. The proposed potential model is extended in deriving important device parameters such as threshold voltage, threshold voltage rolloff, DIBL, subthreshold swing, etc. Model predictions demonstrate that significant improvement in subthreshold operation can be achieved with 4T asymmetric underlap DG MOSFETs in comparison to 3T symmetric nonunderlap DG MOSFETs. © 2012 IEEE.

Chawla P.,Babu Banarasi das National Institute of Technology and Management | Singh R.,Shobhit University | Saraf S.K.,Northern India Engineering College
Medicinal Chemistry Research | Year: 2012

Two novel series of 4-thiazolidinone derivatives, bearing 2-nitrophenyl imino and 4-nitrophenyl imino groups at position-2 and substituted arylidene groups at position-5, have been synthesized and evaluated for antimicrobial activity against four bacterial and one fungal strain. The success of the synthesis of compounds was confirmed on the basis of spectral analysis. All the newly synthesized compounds were obtained in high yields and exhibited good antibacterial activity; however, the antifungal potential was limited to a few agents. © Springer Science+Business Media, LLC 2011.

Tripathi L.,Shobhit University | Singh R.,Shobhit University | Stables J.P.,U.S. National Institutes of Health
European Journal of Medicinal Chemistry | Year: 2011

A series of N′-[substituted] pyridine-4-carbohydrazides were designed and synthesized keeping in view the structural requirement of pharmacophore and evaluated for anticonvulsant activity and neurotoxicity. The anticonvulsant activity of the titled compounds was established after intraperitoneal administration in three seizure models, which include MES, scMET and 6 Hz model. The most active compound of the series was N′-[4-(4-fluorophenoxy) benzylidene]pyridine-4-carbohydrazide PCH 6, which showed a MES ED 50 value of 128.3 mg/kg and 6 Hz ED 50 value of 53.3 mg/kg in mice. The median toxic dose (TD 50) was 343.6 mg/kg, providing compound PCH 6 with a protection index of 2.67 in the MES test and 6.44 in 6 Hz test. A computational study was also carried out, including calculation of pharmacophore pattern, prediction of pharmacokinetic properties and docking studies. © 2010 Elsevier Masson SAS. All rights reserved.

Rai M.K.,Thapar University | Sarkar S.,Shobhit University
Physica Status Solidi (A) Applications and Materials Science | Year: 2011

This paper address the influence of tube diameter on single walled carbon nanotube (CNT) bundle interconnect delay and power output in Very Large Scale application. We find that single-walled carbon nanotube (SWCNT) bundle interconnects are of lower delay than copper interconnect due to low resistance and inductance. Power dissipation decreases with increase in tube diameter of the constituent SWCNT. CNT interconnect resistance and inductance increases with increase in tube diameter. On the other hand, with increase in tube diameter interconnect capacitance decreases. There is a trade off between delay and power dependence on tube diameter. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rai S.,Banaras Hindu University | Singh S.,Shobhit University | Shrivastava A.K.,Banaras Hindu University | Rai L.C.,Banaras Hindu University
Photosynthesis Research | Year: 2013

This study examines response of Anabaena sp. PCC 7120 to salt and UV-B stress by combining physiological, biochemical, proteomics and bioinformatics approaches. Sixty five significantly altered protein spots corresponding to 51 protein genes identified using MALDI-TOF MS/MS were divided into nine functional categories. Based on relative abundance, these proteins were grouped into four major sets. Of these, 27 and 5 proteins were up- and downregulated, respectively, both under salt and UV-B while 8 and 11 proteins showed accumulation in salt and UV-B applied singly. Some responses common to salt and UV-B included (i) enhanced expression of FeSOD, alr3090 and accumulation of MDA indicating oxidative stress, (ii) accumulation of PDH, G6P isomerase, FBPaldolase, TK, GAPDH and PGK suggesting enhanced glycolysis, (iii) upregulation of 6-PGD, 6PGL and NADPH levels signifying operation of pentose phosphate pathway, (iv) upregulation of Dps, NDK and alr3199 indicating DNA damage, and (v) accumulation of proteins of ribosome assembly, transcriptional and translational processing. In contrast, enhanced expression of RUBISCO, increased glycolate oxidase activity and ammonium content under salt signify the difference. Salt was found to be more damaging than UV-B probably due to a cumulative effect of ionic, osmotic and oxidative damage. A group of proteins having common expression represent decreased toxicity of salt and UV-B when applied in combination. © 2013 Springer Science+Business Media Dordrecht.

Gaurav A.,Shobhit University
Mini reviews in medicinal chemistry | Year: 2010

The chemistry of pyrazoloquinolines is well established. This system has proved to be a very attractive scaffold for medicinal chemist in the recent past. Pyrazoloquinolines were extensively studied as bioactive compounds and are known to possess remarkable biological activities such as anti cancer, anti-anxiety, anti-inflammatory, anti-asthmatic, cerebroprotective and antiviral among others. For many of the activities the molecular mode of action is known. Recent research efforts have also highlighted the ability of agents based on pyrazoloquinoline skeleton to modulate adenosine A3 receptors and the phosphodiesterase receptors. In this review the developments in the medicinal chemistry of pyrazoloquinolines is discussed.

Chaudhary A.,Shobhit University | Tiwari N.,Shobhit University | Jain V.,Shobhit University | Singh R.,Shobhit University
European Journal of Pharmaceutics and Biopharmaceutics | Year: 2011

Microporous bilayer osmotic tablet bearing dicyclomine hydrochloride and diclofenac potassium was developed using a new oral drug delivery system for colon targeting. The tablets were coated with microporous semipermeable membrane and enteric polymer using conventional pan-coating process. The developed microporous bilayer osmotic pump tablet (OPT) did not require laser drilling to form the drug delivery orifice. The colon-specific biodegradation of pectin could form in situ delivery pores for drug release. The effect of formulation variables like inclusion of osmogen, amount of HPMC and NaCMC in core, amount of pore former in semipermeable membrane was studied. Scanning electron microscopic photographs showed formation of in situ delivery pores after predetermined time of coming in contact with dissolution medium. The number of pores was dependent on the amount of the pore former in the semipermeable membrane. In vitro dissolution results indicated that system showed acid-resistant, timed release and was able to deliver drug at an approximate zero order up to 24 h. The developed tablets could be effectively used for colon-specific drug delivery to treat IBS. © 2011 Elsevier B.V. All rights reserved.

Jain V.,Shobhit University | Singh R.,Shobhit University
Archives of Pharmacal Research | Year: 2011

The present work was aimed at designing microsponge based colon specific drug delivery system containing paracetamol. Eudragit S-100 based microsponges containing drug in varying amounts were prepared using quasi-emulsion solvent diffusion method. The microsponges were prepared by optimizing various process parameters. DSC and FTIR studies indicated compatibility of the drug in various formulations. Shape and surface morphology of the microsponges were examined using scanning electron microscopy. The formulations were subjected to in vitro release studies and the results were evaluated kinetically and statistically. The in vitro release data showed a bi-phasic pattern with an initial burst effect. In the first hour drug release from microsponges was found to be between 18-30%. The cumulative percent release at the end of 12th hour was noted to be between 74-98%. The release kinetics showed that the data followed Higuchi model and the main mechanism of drug release was diffusion. The colon specific tablets were prepared by compressing the microsponges followed by coating with pectin: hydroxypropylmethyl cellulose (HPMC) mixture. In vitro release studies exhibited that compression coated colon specific tablet formulations started releasing the drug at 6th hour corresponding to the arrival time at proximal colon. The study presents a new approach for colon specific drug delivery. © 2011 The Pharmaceutical Society of Korea and Springer Netherlands.

Jain V.,Shobhit University | Singh R.,Shobhit University
Tropical Journal of Pharmaceutical Research | Year: 2010

Purpose: The purpose of this work was to develop a prolonged microsponge drug delivery system containing dicyclomine. Methods: Dicyclomine-loaded, Eudragit-based microsponges were prepared using a quasi-emulsion solvent diffusion method. The compatibility of the drug with formulation components was established by differential scanning calorimetry (DSC) and Fourier transform infra-red (FTIR). Process parameters were modulated to optimise the formulation. Shape and surface morphology of the microsponges were examined using scanning electron microscopy. Results: The results of compatibility tests showed that no chemical interaction or changes took place during preparation of the formulations; furthermore, the drug was stable in all the formulations. In increase in drug:polymer ratio resulted in a reduction in the release rate of the drug from the microsponges. Kinetic analysis showed that the main mechanism of drug release was by Higuchi matrix-controlled diffusion. Drug release was bi-phasic with an initial burst effect with 16 - 30 % of the drug was released in the first hour. Cumulative release for the microsponges over 8 hours ranged from 59 - 86 %. Conclusion: This study presents an approach for the modification of microsponges for prolonged drug release of dicyclomine. The unique compressibility of microsponges can be applied to achieve effective local action since microsponges may be taken up by macrophages present in colon. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin. All rights reserved.

Vaddi R.,Indian Institute of Technology Roorkee | Dasgupta S.,Indian Institute of Technology Roorkee | Agarwal R.P.,Shobhit University
IEEE Transactions on Electron Devices | Year: 2010

Digital circuits operating in a subthreshold region have gained wide interest due to their suitability for applications requiring ultralow power consumption with low-to-medium performance criteria. It has been demonstrated that by appropriately optimizing the devices for subthreshold logic, total energy consumption can be reduced significantly. One of the major concerns for subthreshold circuit design is increased sensitivity to process, voltage, and temperature (PVT) variations. In this paper, we critically study the effect of variations of different device and environmental parameters like gate oxide thickness, channel length, threshold voltage, supply voltage, temperature, and reverse body bias on subthreshold circuit performance for 32 nm bulk CMOS. From the study, we conclude that alternative devices like double-gate silicon-on-insulator (DGSOI) are better candidates in terms of performance, robustness and PVT insensitivity as compared to bulk circuits for both static CMOS and pseudo NMOS logic families. We also study the performance and robustness comparisons of bulk CMOS and DGSOI subthreshold basic logic gates with and without parameter variations and we observe 6070% improvement in power delay product and roughly 50% better tolerance to PVT variations of DGSOI subthreshold logic circuits compared to bulk CMOS subthreshold circuits at the 32 nm node. © 2006 IEEE.

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