23°7′41″N 72°32′40″ENirma University, popularly known as NU , is an autonomous university located in Ahmedabad, Gujarat, India. It functions under the aegis of Nirma Education and Research Foundation .Nirma University is a statutory university established under the state act. Wikipedia.
Vyas A.P.,Nirma University |
Verma J.L.,Nirma University |
Subrahmanyam N.,Nirma University
Fuel | Year: 2010
Among the options explored for alternative energy sources, bio-diesel is one of the most attractive. This paper discussed about the various production processes, few of which are applied at industrial level also, to produce basically FAME (later can be utilized as bio-diesel after purification) and will be termed as bio-diesel in this paper. Transesterification of vegetable oils/fats and extraction from algae are the leading process options for bio-diesel production on large scale. This paper reviews briefly the literature on transesterification reaction using homogeneous, heterogeneous and enzyme catalysts. Employing also ultrasound, microwave and supercritical alcohol techniques and also algae based bio-diesel. © 2009 Elsevier Ltd. All rights reserved.
Patel B.D.,Nirma University |
Ghate M.D.,Nirma University
European Journal of Medicinal Chemistry | Year: 2014
Dipeptidyl peptidase-4 (DPP-4) is one of the widely explored novel targets for Type 2 diabetes mellitus (T2DM) currently. Research has been focused on the strategy to preserve the endogenous glucagon like peptide (GLP)-1 activity by inhibiting the DPP-4 action. The DPP-4 inhibitors are weight neutral, well tolerated and give better glycaemic control over a longer duration of time compared to existing conventional therapies. The journey of DPP-4 inhibitors in the market started from the launch of sitagliptin in 2006 to latest drug teneligliptin in 2012. This review is mainly focusing on the recent medicinal aspects and advancements in the designing of DPP-4 inhibitors with the therapeutic potential of DPP-4 as a target to convey more clarity in the diffused data. © 2014 Elsevier Masson SAS. All rights reserved.
Bhatt H.G.,Nirma University |
Patel P.K.,Nirma University
Bioorganic and Medicinal Chemistry Letters | Year: 2012
Sodium hydrogen exchanger (SHE) inhibitor is one of the most important targets in treatment of myocardial ischemia. In the course of our research into new types of non-acylguanidine, SHE inhibitory activities of 5-tetrahydroquinolinylidine aminoguanidine derivatives were used to build pharmacophore and 3D-QSAR models. Genetic Algorithm Similarity Program (GASP) was used to derive a 3D pharmacophore model which was used in effective alignment of data set. Eight molecules were selected on the basis of structure diversity to build 10 different pharmacophore models. Model 1 was considered as the best model as it has highest fitness score compared to other nine models. The obtained model contained two acceptor sites, two donor atoms and one hydrophobic region. Pharmacophore modeling was followed by substructure searching and virtual screening. The best CoMFA model, representing steric and electrostatic fields, obtained for 30 training set molecules was statistically significant with cross-validated coefficient (q2) of 0.673 and conventional coefficient (r2) of 0.988. In addition to steric and electrostatic fields observed in CoMFA, CoMSIA also represents hydrophobic, hydrogen bond donor and hydrogen bond acceptor fields. CoMSIA model was also significant with cross-validated coefficient (q2) and conventional coefficient (r2) of 0.636 and 0.986, respectively. Both models were validated by an external test set of eight compounds and gave satisfactory prediction (r2 pred) of 0.772 and 0.701 for CoMFA and CoMSIA models, respectively. This pharmacophore based 3D-QSAR approach provides significant insights that can be used to design novel, potent and selective SHE inhibitors. © 2012 Elsevier Ltd. All rights reserved.
Ghatak S.B.,Nirma University
Current diabetes reviews | Year: 2010
Type 2 diabetes mellitus causes significant morbidity and mortality on account of its progressive nature and results in considerable burden on healthcare resources. It is characterized by high circulating levels of glucose resulting from insulin resistance and impaired insulin secretion. Current treatment strategies have only limited long-term efficacy and tolerability given the progressive nature of the disease leading to inadequate glycemic control and are also associated with undesirable side effects such as weight gain, hypoglycemia and gastrointestinal distress. In the light of these existing limitations, exploring new treatment targets and new therapies have become the need of the hour at present. The incretin pathway, in particular, glucagon-like peptide (GLP-1), plays an important pathological role in the development of type 2 diabetes mellitus, and treatments targeting the incretin system have recently generated surmount interest. These can mainly be categorized into two broad classes; GLP-1 agonists/analogs (exenatide, liraglutide), and dipeptidyl peptidase- 4 inhibitors (sitagliptin, vildagliptin). The gliptins act by prolonging the action of incretins, the gut hormones which can boost insulin levels. Alogliptin is a potent, highly selective dipeptidyl peptidase-4 inhibitor now undergoing clinical testing to support a new drug application for the treatment of type 2 diabetes. The results of Phase II and Phase III human studies, upon evaluation for clinical efficacy, safety and tolerability in patients with type 2 diabetes, have demonstrated that Alogliptin is effective and well tolerated as a treatment for type 2 diabetes, either as monotherapy or in combination with metformin, thiazolidinediones, sulfonylureas and insulin, with an excellent safety profile.
Sharma D.S.,Nirma University
International Journal of Mechanical Sciences | Year: 2012
General solutions for determining the stress distribution around holes in an infinite plate subjected to arbitrary biaxial in-plane loadings at infinity, are obtained using Muskhelishvili's complex variable method. The stress functions are obtained by evaluating Cauchy's integral for the given boundary conditions. The generalized formulation thus obtained is coded and numerical results are presented for triangular, square, pentagonal, hexagonal, heptagonal and octagonal cut-out. The effect of the hole geometry and loading pattern on the stress concentration factor is studied. For some of the cases, plane stress finite element models are prepared in ANSYS and results are compared with present method. © 2012 Elsevier Ltd.
Adhyaru D.M.,Nirma University
Applied Soft Computing Journal | Year: 2012
In this paper, an observer design is proposed for nonlinear systems. The Hamilton-Jacobi-Bellman (HJB) equation based formulation has been developed. The HJB equation is formulated using a suitable non-quadratic term in the performance functional to tackle magnitude constraints on the observer gain. Utilizing Lyapunov's direct method, observer is proved to be optimal with respect to meaningful cost. In the present algorithm, neural network (NN) is used to approximate value function to find approximate solution of HJB equation using least squares method. With time-varying HJB solution, we proposed a dynamic optimal observer for the nonlinear system. Proposed algorithm has been applied on nonlinear systems with finite-time-horizon and infinite-time-horizon. Necessary theoretical and simulation results are presented to validate proposed algorithm. © 2012 Elsevier B.V.
Jain S.V.,Nirma University |
Patel R.N.,Nirma University
Renewable and Sustainable Energy Reviews | Year: 2014
In remote communities where it is not economical and practically possible to take the grid connection, stand-alone small hydro systems can be used to fulfill the energy requirement. Small-scale hydroelectric power systems are emerging as a promising source of renewable energy generation, but they require low cost hydraulic and electric equipments to make them economically feasible. In such plants, pumps can be used in turbine mode considering various advantages associated with pump e.g. ease of availability, proven technology, low initial and maintenance cost, availability for a wide range of heads and flows, etc. The efficiency of pump as turbine (PAT) is usually lower than that of conventional hydro turbines. However, efficiency is not the primary selection criterion for such machines and it is recommended to operate such machines around maximum efficiency point. In the present study, different turbines suitable for micro-hydropower plants are discussed. The historical development of PAT is described. The review of the state-of-the-art of pump running in turbine mode is presented. Different pumps suitable to run in turbine mode for low capacity power generation in micro-hydropower plants as well as in water supply piping systems are discussed. Theoretical, experimental and numerical investigations carried out by different researchers on PAT are reviewed. The research work on PAT including criteria for selection of pump running as turbine, cavitation analysis, force analysis, loss distribution, various methods of performance enhancement, cost analysis of hydropower plant with conventional hydro turbine and PAT, applications of PAT in water supply pipelines, etc. is discussed. The worldwide implementation of PAT and different manufacturers of PAT are described. The limitations in implementation of PAT as well as the recommendations to improve the performance of PAT are described. The current trends and future scope for the further improvement and implementation of PAT are also discussed. © 2013 Elsevier Ltd.
Sharma D.S.,Nirma University
International Journal of Mechanical Sciences | Year: 2014
General solutions for determining the moment distribution around polygonal holes in infinite isotropic plate subjected to bending/twisting moment at infinity are obtained using Muskhelishvili's complex variable method. The conformal mapping and biaxial loading factor is introduced to take care hole geometry and loading conditions. The generalized formulation thus obtained is coded and numerical results are obtained for triangular, square, pentagonal, hexagonal, heptagonal and octagonal cut-outs. The effect of hole geometry and loading pattern on moment distribution is studied. © 2013 Elsevier Ltd.
Sharma D.S.,Nirma University
Engineering Letters | Year: 2012
General stress functions for determining the stress concentration around circular, elliptical and triangular cutouts in laminated composite infinite plate subjected to arbitrary biaxial loading at infinity are obtained using Muskhelishvili's complex variable method. The generalized stress functions are coded using MATLAB and the effect of fiber orientation, stacking sequence, loading factor, loading angle and cutout geometry on stress concentration around cutouts in orthotropic/anisotropic plates is studied. Some of the results are compared with existing literature and finite element solutions.
Goyal B.R.,Nirma University |
Mehta A.A.,JKK Nataraja Dental College and Hospital
Human and Experimental Toxicology | Year: 2013
Several experimental, pathological, epidemiological, and clinical studies have clearly depicted that diabetes mellitus results in cardiac functional and structural changes. Diabetic cardiomyopathy results in both structural and functional alterations in the myocardium. Several mechanisms have been implicated in the pathophysiology of diabetic cardiomyopathy. Of these, metabolic disturbances, myocardial fibrosis, small vessel disease, and cardiac autonomic neuropathy are the major players in the pathophysiology of diabetic cardiomyopathy. This review is intended to discuss various such pathophysiological mechanisms of diabetic cardiomyopathy. We have also described the systolic and diastolic dysfunctioning and its corelation to structural changes in diabetes. © 2013 The Author(s).