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Papers by amit tripathi

Acta biomaterialia, Jan 5, 2017

Introducing cell-selectivity in antimicrobial peptides (AMPs) without compromising the antimicrob... more Introducing cell-selectivity in antimicrobial peptides (AMPs) without compromising the antimicrobial and anti-endotoxin properties is a crucial step towards the development of new antimicrobial agents. A peptide designed on phenylalanine heptad repeat possesses significant cytotoxicity along with desired antimicrobial and anti-endotoxin properties. Amino acid substitutions at 'a' and/or 'd' positions of heptad repeats of AMPs could alter their helical structure in mammalian membrane-mimetic environments and cytotoxicity towards mammalian cells. Since proline is a helix breaker, effects of selective proline substitution(s) at 'a' and/or 'd' positions of a 15-residue peptide designed on phenylalanine heptad repeat (FR-15) were investigated. Proline-substituted FR-15 variants were highly selective toward bacteria and fungi over hRBCs and murine 3T3 cells and also retained their antibacterial activities at high salt, serum and elevated temperatures. These...

Materials Chemistry and Physics, 2017

Abstract Exciting properties of carbon nanotube has proven it to be a promising candidate for fie... more Abstract Exciting properties of carbon nanotube has proven it to be a promising candidate for field emission applications, if its processing cost can be reduced effectively. In this research, a new electrochemical technique is proposed for growing carbon nanotubes in selective areas by thermal chemical vapour deposition. In this process, electrochemical processing is used to create localized pits and deposition of catalysts, which act as roots to support growth and alignment of the CNTs on copper substrate. CNTs grown thus were characterized and studied using scanning electron microscope, transmission electron microscope and Raman spectroscopy, elucidating presence of multiwall carbon nanotubes (MWCNT). These CNT emitters have comparatively lower turn-on field and higher field enhancement factor.

Plant Diversity, 2017

The lowland rainforests of Meghalaya, India represent the westernmost limit of the rainforests no... more The lowland rainforests of Meghalaya, India represent the westernmost limit of the rainforests north of the Tropic of Cancer. These forests, on the Shillong plateau, are akin to Whitmore's 'tropical lowland evergreen rainforest' formation and exhibit striking similarities and conspicuous differences with the equatorial rainforests in Asia-Pacific as well as tropical seasonal rainforests in southwestern China near the Tropic of Cancer. We found these common attributes of the rainforests in Meghalaya: familial composition with predominance of Euphorbiaceae, Lauraceae, Meliaceae, Moraceae, Myrsiticaceae, Myrtaceae and Rubiaceae; deciduousness in evergreen physiognomy; dominance of mega-and mesophanerophytic life-forms; abundance of species with low frequency of occurrence (rare and aggregated species); low proportional abundance of the abundant species; and truncated lognormal abundance distribution. The levels of stand density and stand basal area were comparable with seasonal rainforests in southwestern China, but were lower than equatorial rainforests. Tropical Asian species predominated flora, commanding 95% of the abundance. The differences include overall low stature (height) of the forest, inconspicuous stratification in canopy, fewer species and individuals of liana, thicker understory, higher proportion of rare species, absence of locally endemic species and relatively greater dominance of Fagaceae and Theaceae. The richness of species per hectare (S) was considerably lower at higher latitudes in Meghalaya than in equatorial rainforests, but was comparable with seasonal rainforests. Shannon's diversity index (H 0 ¼ 4.40 nats for !10 cm gbh and 4.25 nats for !30 cm gbh) was lower on higher latitudes in Meghalaya in comparison to species-rich equatorial rainforests, but it was the highest among all lowland rainforests near the Tropic of Cancer.

The Biochemical journal, Jan 8, 2016

13-residue frog antimicrobial peptide Temporin L (TempL) possesses versatile antimicrobial activi... more 13-residue frog antimicrobial peptide Temporin L (TempL) possesses versatile antimicrobial activities and is considered as a lead molecule for the development of new antimicrobial agents. To find out the amino acid sequence(s) that influence the antimicrobial property of TempL, a phenylalanine zipper like sequence was identified in it which was not reported earlier. To evaluate the role of this motif, several alanine-substituted analogs and a scrambled peptide having the same composition of TempL were designed. To investigate if leucine residues instead of phenylalanine residues at 'a' and/or…

IFAC Proceedings Volumes, 2014

ABSTRACT An effective reactive collision avoidance algorithm is presented in this paper for Unman... more ABSTRACT An effective reactive collision avoidance algorithm is presented in this paper for Unmanned Ariel Vehicles (UAVs) based on stereovision sensing of the obstacles. Vision sensors detection range is limited and state measurements are noisy. Unscented Kalman Filter (UKF) based sensor state estimation is proposed to extract the accurate information from the sensors through a geometrical formulation. This formulation is capable of estimating the range information of the obstacle. The first order differential of the nonlinear sensor dynamics is used to compute obstacles velocity estimate. In the case of imminent collision, UAV is guided towards an Aiming point which is computed for point obstacle with safety ball and using the collision cone approach. The velocity vector of the UAV is steered away towards this point by using Differential Geometry Guidance(DGG). Simulations show that this guidance strategy is quite effective in avoiding popup obstacles within a very short time and hence can be useful for reactive collision avoidance.

Let X be a smooth projective hypersurface. In this note we show that any six generated arithmetic... more Let X be a smooth projective hypersurface. In this note we show that any six generated arithmetically Cohen-Macaulay vector bundle over X splits if dim X ≥ 6.

Antimicrobial agents and chemotherapy, Jun 11, 2016

Piscidin-1 possesses both significant antimicrobial and cytotoxic activities. To recognize primar... more Piscidin-1 possesses both significant antimicrobial and cytotoxic activities. To recognize primary amino acid sequence(s) in piscidin-1 that could be important for its biological activity, a long heptad repeat sequence located in the amino acid region 2 to 19 was identified. To comprehend the possible role of this motif, six analogs of piscidin-1 were designed by selectively replacing a single isoleucine residue at a 'd' position (5(th)) or at an…

Cancer biology & medicine, 2015

Epithelial ovarian cancer (EOC) is the leading cause of death among all gynecological malignancie... more Epithelial ovarian cancer (EOC) is the leading cause of death among all gynecological malignancies. Despite the technological and medical advances over the past four decades, such as the development of several biological markers (mRNA and proteins biomarkers), the mortality rate of ovarian cancer remains a challenge because of its late diagnosis, which is specifically attributed to low specificities and sensitivities. Under this compulsive scenario, recent advances in expression biology have shifted in identifying and developing specific and sensitive biomarkers, such as microRNAs (miRNAs) for cancer diagnosis and prognosis. MiRNAs are a novel class of small non-coding RNAs that deregulate gene expression at the posttranscriptional level, either by translational repression or by mRNA degradation. These mechanisms may be involved in a complex cascade of cellular events associated with the pathophysiology of many types of cancer. MiRNAs are easily detectable in tissue and blood sample...

International Journal of Computer Mathematics, 2015

ABSTRACT This research study presents a numerical scheme to compute approximate solutions of two ... more ABSTRACT This research study presents a numerical scheme to compute approximate solutions of two dimensional unsteady convection–diffusion equation. We used collocation of modified bi-cubic B-spline functions for dependent variable u and for its derivatives w.r.t. space variables x and y. Strong stability preserving Runge–Kutta method (SSP-RK54) has been used for solving system of first-order ordinary differential equations obtained from the collocation form of the partial differential equation. We did not linearize the nonlinear terms by using any transformation or linearization method. The number of computations and the required storage space is very less for the proposed scheme. Four examples have been taken as described in available literature to demonstrate the effect and utility of the proposed scheme. These numerical experiments show that the obtained results are not only quite satisfactory w.r.t. the exact solutions but also competent with the solutions available in earlier research studies. Computational complexity of the proposed scheme has been discussed and shown that it is , where p is total number of nodes. The proposed scheme is easy to implement and the size of required computational work is very small. Moreover, using this scheme, we can compute approximate solutions not only at the mesh points but at any other point of the solution domain as well.

Macromolecular Theory and Simulations, 2014

ABSTRACT Monte Carlo simulation methods are suitable for free radical polymerizations (FRP) even ... more ABSTRACT Monte Carlo simulation methods are suitable for free radical polymerizations (FRP) even when there is significant chain length dependence of the reactions. For each simulation step the probability of each possible reaction is determined at that point in time. In FRP modeling most of the computation time is spent on radical propagation. We demonstrate a hybrid simulation method where the propagation reaction is treated using differential equations and other reactions (e.g. termination and initiation reactions) are treated stochastically. This allows significant reductions in simulation time while maintaining the features of complete Monte Carlo methods. This approach can be applied to more complex polymerization reactions like branching and crosslinking using Monte Carlo methods within manageable times.

Worldwide the population growth is increased every year and people over 65 ratios is growing rapi... more Worldwide the population growth is increased every year and people over 65 ratios is growing rapidly. The healthcare system and hospitals are very less and facing challenges to provide better service. Energy plays vital role in healthcare monitoring devices and systems. Integrating WBANs (Wireless Body Area Networks) and WSNs (Wireless Sensor Networks) can help in providing better quality of life. In this paper possibilities of achieving integration of WBAN and WSN, energy efficiency, and quality of life are discussed. Also, time and energy aware routing protocol (TEA) and healthcare model is proposed. Simulation results show that this approach can help in improving energy efficiency and quality of life.

Industrial & Engineering Chemistry Research, 2015

ABSTRACT In an extension of our recent studies on the distribution of vinyl acid (AA and MAA) and... more ABSTRACT In an extension of our recent studies on the distribution of vinyl acid (AA and MAA) and hydroxy (meth)acrylate monomers in emulsion polymerization systems, we report the distribution behavior of 2-carboxyethyl acrylate (CEA) between water and various nonfunctional monomers. Similar to that previously reported for AA and MAA, the distribution of CEA strongly depends upon the hydrogen bond acceptor characteristics of the non-functional monomer organic phase. The log of the distribution coefficients for CEA correlate linearly with the molar volume of (meth)acrylate monomers. The CEA molecule is a replica of 2-hydroxyethyl acrylate (HEA) with a different functional group. The evaluation of the distribution behaviors of CEA and HEA allows for a direct comparison of the carboxyl and hydroxyl moieties in determining the distributions. The strong dipole moment of the hydroxy group makes HEA significantly more polar than CEA. Also comparisons of the distribution behaviors of CEA with those for AA and MAA allow us to understand the combined effect of the ester and carboxylic acid groups in the CEA on the overall polarity of these vinyl acid monomers and their distribution behaviors.

Engineering Computations, 2015

Purpose – The purpose of this paper is to develop an efficient numerical scheme for non-linear tw... more Purpose – The purpose of this paper is to develop an efficient numerical scheme for non-linear two-dimensional (2D) parabolic partial differential equations using modified bi-cubic B-spline functions. As a test case, method has been applied successfully to 2D Burgers equations. Design/methodology/approach – The scheme is based on collocation of modified bi-cubic B-Spline functions. The authors used these functions for space variable and for its derivatives. Collocation form of the partial differential equation results into system of first-order ordinary differential equations (ODEs). The obtained system of ODEs has been solved by strong stability preserving Runge-Kutta method. The computational complexity of the method is O(p log(p)), where p denotes total number of mesh points. Findings – Obtained numerical solutions are better than those available in literature. Ease of implementation and very small size of computational work are two major advantages of the present method. Moreove...

the Rooftop Wind Turbine provides an attractive sustainable solution in the field of energy, with... more the Rooftop Wind Turbine provides an attractive sustainable solution in the field of energy, with the benefit of safe environment for future generations. Small wind electric system can make a significant contribution to our nation’s energy need. And now yet there is no such wind power generation system that can produce energy and can fulfil the requirement of individual houses in India. Typical wind turbines are sufficiently large so as to require large space for their installation and operation. On the other hand, smaller turbine system has required less area and they can be practically installed at top of the tall buildings .In this work of wind power generation into a tall building design, the first consideration must be the local wind climate of the area. For this we have collected data for different locations in India and then analyse the power generation capacity of rooftop wind turbine, force exerted by the wind turbine system on the building. To check the feasibility of roof...

In this work, we present a new methodology to obtain numerical solutions of symmetric regularized... more In this work, we present a new methodology to obtain numerical solutions of symmetric regularized long wave equations. Our approach is based on collocation of modified cubic B-spline basis functions over the finite elements. First, we discretize the given equation in space and then we use collocation of modified cubic B-spline basis functions for unknown dependent variables u, v and their derivatives w.r.t. space variable x, which produces a system of first order ordinary differential equations. This system of differential equations has been solved by SSP-RK54 scheme. The stability of the method has been discussed and shown that it is unconditionally stable. The efficiency of the proposed method has been confirmed with numerical experiments, which shows that the obtained results are acceptable and are in good agreement with earlier studies. Ease of implementation and very small size of computational work are two major advantages of this approach. Moreover, this method provides appro...

Macromolecules, 2015

ABSTRACT A computationally efficient Monte Carlo method was used to simulate the reaction kinetic... more ABSTRACT A computationally efficient Monte Carlo method was used to simulate the reaction kinetics and molecular structure development during free-radical copolymerizations with divinyl monomers. A single parameter was used to describe the reduced reactivity of the pendent vinyl groups incorporated within the polymer backbone. The simulation results were compared with published experimental data for the bulk copolymerization of methyl methacrylate with different levels of ethylene glycol dimethacrylate. The model was able to effectively predict the reaction kinetics, the gel point, and sol–gel fractions in both the pre- and postgel regimes, including the swelling index of the gel. In the postgel regime the cross-linked molecule becomes the primary locus of reactions, and all chains eventually become part of this massive cross-linked polymer network. The Monte Carlo method allows the determination of the complete molecular structure as it evolves with time, including properties like cross-linking density, number of free chain ends, primary cycles and loops, and the fraction of unreacted pendent vinyl groups.

Elucidation of Abiotic Stress Signaling in Plants, 2015