<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

(SoNS) School of Natural Sciences

Background: Malaria remains the world's most important devastating parasitic disease. Of the five species of Plasmodium known to infect and cause human malaria, Plasmodium falciparum is the most virulent and responsible for majority of the deaths caused by this disease. Mainstream drug therapy targets the asexual blood stage of the malaria parasite, as the disease symptoms are mainly associated with this stage. The prevalence of malaria parasite strains resistance to existing anti-malarial drugs has made the control of malaria even more challenging and hence the development of a new class of drugs is inevitable. Methods: Screening against different drug resistant and sensitive strains of P. falciparum was performed for few bicyclic lactam-based motifs, exhibiting a broad spectrum of activity with low toxicity generated via a focussed library obtained from diversity oriented synthesis (DOS). The synthesis and screening was followed by an in vitro assessment of the possible cytotoxic effect of this class of compounds on malaria parasite. Results: The central scaffold a chiral bicyclic lactam (A) and (A') which were synthesized from (R)-phenylalaninol, levulinic acid and 3-(2-nitrophenyl) levulinic acid respectively. The DOS library was generated from A and from A', by either direct substitution with o-nitrobenzylbromide at the carbon a-to the amide functionality or by conversion to fused pyrroloquinolines. Upon screening this diverse library for their anti-malarial activity, a dinitro/diamine substituted bicyclic lactam was found to demonstrate exceptional activity of >85\% inhibition at 50 μM concentration across different strains of P. falciparum with no toxicity against mammalian cells. Also, loss of mitochondrial membrane potential, mitochondrial functionality and apoptosis was observed in parasite treated with diamine-substituted bicyclic lactams. Conclusions: This study unveils a DOS-mediated exploration of small molecules with novel structural motifs that culminates in identifying a potential lead molecule against malaria. In vitro investigations further reveal their cytocidal effect on malaria parasite growth. It is not the first time that DOS has been used as a strategy to identify therapeutic leads against malaria, but this study establishes the direct implications of DOS in scouting novel motifs with anti-malarial activity. © 2014 Sharma et al.

World University root node

Chemistry

Fulltext

Malaria Journal

Diversity-oriented synthesis and activity evaluation of substituted bicyclic lactams as anti-malarial against Plasmodium falciparum

Benzoxazine (Bz) monomer was synthesized from renewable cardanol, a by-product from cashew-nut industry, using a solventless approach. The monomer was encapsulated in poly(styrene) (PS) shells by solvent evaporation technique to obtain spherical microcapsules. The microcapsule dimensions and core content could be tailored by optimizing the operating parameters, particularly stirring speed and PS concentration. Successful demonstration of this simple and versatile methodology widens the scope for large-scale application of benzoxazines in the field of self-healing. © 2014 Elsevier Ltd. All rights reserved.

Materials Letters

Microencapsulated cardanol derived benzoxazines for self-healing applications

In this paper, a fluence-dependent antireflection performance is presented from ion-beam fabricated nanofaceted-Si surfaces. It is also demonstrated that these nanofacets are capable of producing room temperature ultra-violet and blue photoluminescence which can be attributed to inter-band transitions of the localized excitonic states of different Si-O bonds at the Si/SiOx interface. Time-resolved photoluminescence measurements further confirm defect-induced radiative emission from the surface of silicon nanofacets. It is observed that the spectral characteristics remain unchanged, except an enhancement in the photoluminescence intensity with increasing ion-fluence. The increase in photoluminescence intensity by orders of magnitude stronger than that of a planar Si substrate is due to higher absorption of incident photons by nanofaceted structures. © 2014 AIP Publishing LLC.

Physics

Journal of Applied Physics

Tailoring room temperature photoluminescence of antireflective silicon nanofacets

The lithium storage mechanism in molybdenum disulfide (MoS2) has been comprehensively investigated as the existing conversion-based storage mechanism is unable to explain the reason behind its high practical capacity, high polarization losses, and the change in the discharge profile after the 1st charge-discharge cycle. To resolve these issues and to gain a deeper understanding of MoS2-based Li-ion batteries, for the first time, we have studied the reaction mechanism of the MoS2 anode using various experimental techniques such as XRD, Raman spectroscopy, electrochemical impedance spectroscopy, XANES, and EXAFS, as well as ab initio density functional theory based calculations. On the basis of the results presented here, and in line with some experimental findings, we find that the reaction of MoS2 with Li is not as simple as with usual metal oxide based conversion reactions, but that the pathway of the conversion reaction changes after the first discharge process. In the first discharge process, lithiation is initiated by a limited intercalation process, followed by a conversion reaction that produces molybdenum nanoparticles (Mo) and lithium sulfide (Li 2S). Whereas, unlike oxide-based conversion materials, MoS 2 does not transverse back during the delithiation process. Indeed, instead of MoS2 formation, we identified the presence of polysulfur after the complete cycle. In consecutive cycles, polysulfur reacts with lithium and forms Li2S/Li2S2, and this Li-S reaction is found to be highly reversible in nature and the only source of the high practical capacity observed in this electrode. To validate our experimental findings, an atomic scale ab initio computational study was also carried out, which likewise suggests that Li first intercalates between the MoS2 layers but that after a certain concentration, it reacts with MoS2 to form Li2S. The calculations also support the non-reversibility of the conversion reaction, by showing that Mo + Li2S formation is energetically more favorable than the re-formation of MoS2 + Li. © 2014 the Partner Organisations.

Nanoscale

An experimental and computational study to understand the lithium storage mechanism in molybdenum disulfide

The application of computational tools can alleviate the challenges (viz. time consumption and cost intensiveness) in drug design. Metaheuristics, a collection of such diverse computational and mathematical tools, whose first application was dated back to the early 1970s, caters to several expectations of rational drug designing. Among the population-based metaheuristics, genetic algorithms most closely mimic natural selection. As a consequence, they are rapidly garnering popularity over other members of evolutionary computation as the most preferred simulation processes for drug trials and designing. This chapter discusses various applications of genetic algorithms in drug design, from designing a combinatorial library, QSAR/QSPR study, and designing lead candidacy in drug discovery to solutions for genetic disease. Genetic algorithms find their place in all. © 2014 Springer International Publishing Switzerland. All rights reserved.

Mathematics

Applications of Metaheuristics in Process Engineering

Genetic algorithms in drug design: A not-so-old story in a newer bottle

Due to the fact that much of the world's best solar resources are inversely correlated with population centers, significant motivation exists for developing technology which can deliver reliable and autonomous conversion of sunlight into electricity. Thermoelectric generators are gaining incremental ground in this area since they do not require moving parts and work well in remote locations. Thermoelectric materials have been extensively used in space satellites, automobiles, and, more recently, in solar thermal applications as power generators, known as solar thermoelectric generators (STEG). STEG systems are gaining significant interest in both concentrated and non-concentrated systems and have been employed in hybrid configurations with solar thermal and photovoltaic systems. In this article, the key developments in the field of thermoelectric materials and on-going research work on STEG design conducted by various researchers to date are critically reviewed. Finally, we highlight the strategic research directions being undertaken to make highly efficient thermoelectric materials for developing a cost-effective STEG system, which could serve to bring this technology towards commercial readiness. This journal is © the Partner Organisations 2014.

RSC Advances

Recent advances in thermoelectric materials and solar thermoelectric generators-a critical review

A versatile stereoselective diversity oriented synthetic pathway to the possible spiro and fused diverse heterocyclic small molecules is described. The strategy involved the "build-couple-pair" approach involving an S NAr, Michael addition and Mannich reaction on chiral acyl bicyclic lactams 2a/b, followed by a cyclization onto the inbuilt scaffold electrophile, thereby leading to asymmetric fused and spirocyclic nitrogen heterocycles. A "post-pair" phase has been incorporated to generate more polar compounds. We used Principal Component Analysis (PCA) and polar moment of inertia to evaluate the shape-space diversity of our scaffolds with respect to a commercial database and observed extraordinary diversity within the scaffold network. We further calculated the polar surface area (PSA) of our molecules which is an indicator for drug cell permeability. © 2014 The Royal Society of Chemistry.

Pyrrolidine and piperidine based chiral spiro and fused scaffolds via build/couple/pair approach

Room temperature irradiation of InSb(111) by 60keV Ar+-ions at normal (0°) and oblique (60°) angles of incidence led to the formation of nanoporous structure in the high fluence regime of 1×1017 to 3×1018 ions cm-2. While a porous layer comprising of a network of interconnected nanofibers was generated by normal ion incidence, evolution of plate-like structures was observed for obliquely incident ions. Systematic studies of composition and structure using energy dispersive x-ray spectroscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, Raman mapping, grazing incidence x-ray diffraction, and cross-sectional transmission electron microscopy revealed a high degree of oxidation of the ion-induced microstructures with the presence of In2O3 and Sb2O3 phases and presence of nanocrystallites within the nanoporous structures. The observed structural evolution was understood in terms of processes driven by ion-induced defect accumulation within InSb. © 2014 AIP Publishing LLC.

60 keV Ar+-ion induced modification of microstructural, compositional, and vibrational properties of InSb

Effects of acid concentration on excited state intramolecular charge transfer reaction of 4-(azetidinyl) benzonitrile (P4C) in aprotic (acetonitrile and ethyl acetate) and protic (ethanol) solvents have been studied by means of steady state absorption and fluorescence, and time resolved fluorescence spectroscopic techniques. While absorption and fluorescence bands of P4C have been found to be shifted towards higher energy with increasing acid concentration in acetonitrile and ethyl acetate, no significant dependence has been observed in ethanolic solutions. Reaction rate becomes increasingly slower with acid concentration in acetonitrile and ethyl acetate. In contrast, acid in ethanolic solutions does not produce such an effect on reaction rate. Time-dependent density functional theory calculations have been performed to understand the observed spectroscopic results. © Indian Academy of Sciences.

Journal of Chemical Sciences

Effects of acid concentration on intramolecular charge transfer reaction of 4-(azetidinyl) benzonitrile in solution

Models of biochemical networks are frequently complex and high-dimensional. Reduction methods that preserve important dynamical properties are therefore essential for their study. Interactions in biochemical networks are frequently modeled using Hill functions (xn/Jn+xn). Reduced ODEs and Boolean approximations of such model networks have been studied extensively when the exponent n is large. However, while the case of small constant J EquationSource&gt; appears in practice, it is not well understood. We provide a mathematical analysis of this limit and show that a reduction to a set of piecewise linear ODEs and Boolean networks can be mathematically justified. The piecewise linear systems have closed-form solutions that closely track those of the fully nonlinear model. The simpler, Boolean network can be used to study the qualitative behavior of the original system. We justify the reduction using geometric singular perturbation theory and compact convergence, and illustrate the results in network models of a toggle switch and an oscillator. © 2014, Society for Mathematical Biology.