Browsing by Issue Date, starting with "2018"

Now showing 1 - 20 of 1561

Electron transfer in biologically important systems: Polycyclic aromatic hydrocarbons, DNA bases and free radicals
(World Scientific Publishing Co. Pte Ltd, 2018) M.K. Tiwari; P.C. Mishra
Occurrence of electron transfer was studied for different combinations of polycyclic aromatic hydrocarbons (PAHs) and DNA bases as electron donors or acceptors and free radicals only as electron acceptors. Geometries of all the molecules and radicals were optimized in aqueous medium employing the polarizable continuum model. Single electron transfer (SET) and sequential proton loss electron transfer mechanisms were investigated employing Gibbs free energies of the appropriate neutral, anionic and cationic species. Barrier energies involved in these phenomena were calculated using the Marcus theory. The SET barrier energies were found to be linearly correlated with ΔE= (Electron affinities of acceptors - Ionization potentials of donors). SET barrier energies from the DNA bases to the PAHs follow the order Cy > Th ≈ Ad > Gu, whereas SET barrier energies from the PAHs to the DNA bases follow the order Gu > Ad > Th ≈ Cy. Thus, guanine, among the DNA bases, is the best electron donor to the PAHs and worst electron acceptor from the same. © 2018 World Scientific Publishing Company.
Antioxidants in the prevention and treatment of alzheimer’s disease
(Springer International Publishing, 2018) Sandeep Kumar Singh; Saripella Srikrishna; Rudy J. Castellani; George Perry
Alzheimer’s disease (AD) is the most common human neurodegenerative disease that causes dementia in the elderly. A person suffering with AD shows gradual memory deterioration and other cognitive discrepancies, which eventually lead to complete incapacity and ultimately death. The major pathological characteristics of AD are the presence of senile plaques extracellularly and neurofibrillary tangles intracellularly. Growing evidences have demonstrated that oxidative stress is an important factor contributing to the initiation and progression of AD. However, the exact mechanisms that lead to the disruption of redox balance and the sources of free radicals remain elusive. The excessive reactive oxygen species may be generated from mechanisms such as mitochondrial dysfunction and/or aberrant accumulation of transition metals, while the abnormal accumulation of amyloid-β protein (Aβ) and tau proteins appears to promote redox imbalance. The resulting oxidative stress has been implicated in Aβ or tau-induced neurotoxicity. To combat oxidative stress in AD, antioxidants have been therapeutically implicated. Within the last few years, a number of polyphenolic compounds with antioxidant and neuroprotective effects have been described to possibly benefit AD patients. Many efforts have been made to explore the mechanisms behind the neuroprotective action of polyphenols. The aim of this chapter is to critically review the use of different types of antioxidants in the prevention and treatment of AD. © Springer International Publishing AG 2017.
Harmful effects of ecosystem impairment on human health
(IGI Global, 2018) Suruchi Singh; Shashi Bhushan Agrawal; Madhoolika Agrawal
Growing global population has caused environment degradation through ecosystem impairment and over exploitation. Although, people have made great moves for improving life style, and enjoy a drastically improved quality of life but such improvements have been made at the cost of environment degradation. Climate change will force humans to adjust with changing environment and find ways to deal with short term protection and long term health consequences. The range of potential threats to human health caused by climate change is increasing and at the same time is not clear. So, owing to the potential magnitude and universality of such an issue, we have a moral obligation for developing proper tools and make informed choices that ultimately result in better lives for the humans. © 2018 by IGI Global. All rights reserved.
Study of soil cyanobacteria along a rural-urban gradient
(Elsevier B.V., 2018) Pradeep Kumar Rai; Anuradha Rai; Naveen Kumar Sharma; Surendra Singh
Urbanization is one of the modern and critical factors adversely affecting global biodiversity. The impact of urbanization on soil microbial diversity has sporadically been studied of cyanobacterial diversity. The present study analyzes morphological as well as molecular diversity of cyanobacteria along a rural-urban gradient using a culture based approach. In total, 22 cyanobacterial morphotypes (14 genera and 21 species) from five orders were reported; dominated by the members of the order Nostocales. In general, cyanobacterial diversity decreased from rural to urban areas; with N2-fixing heterocystous forms dominating the cyanobacterial flora of the urban area. The values of Shannon–Weaver (2.56) and Simpson's (2.32) indices suggested higher cyanobacterial diversity in the rural area compared to that of the sub-urban and urban areas. Statistical analyses established the importance of physico-chemical factors in structuring the cyanobcaterial communities along the gradient with soil characteristics such as – pH, organic carbon, nitrogen and bulk density, directly as well as indirectly. © 2018 Elsevier B.V.
Dynamic modulation of refractive index in Y-X LiNbO3 slab through lamb wave
(Institute of Electrical and Electronics Engineers Inc., 2018) Suraj Prakash; Gaurav Sharma; Gulab Chand Yadav; Vivek Singh
Refractive index contrast generation, due to induced modulation of refractive index in Y-X LiNbO3 slab by Lamb wave has been studied theoretically. Acoustic frequency and corresponding wavelength is chosen to excite S0 Lamb mode in 400nm thick slab using Rayleigh-Lamb frequency relations. Propagation of Lamb wave produces strain in the slab and modulates refractive index. This modulation is responsible to produce refractive index contrast. Sinusoidal variation of refractive index has been found in slab with a period equals to wavelength of excited Lamb mode. The obtained maximum variation in refractive index along X is of order 0.0166 with respect to unperturbed value 2.28 in 400nm thick Y-X LiNbO3 slab at 5GHz Lamb wave frequency. These contrast variations along both X and Y directions decrease with increase in slab thickness. © 2017 IEEE.
Differential characterization of myogenic satellite cells with linolenic and retinoic acid in the presence of thiazolidinediones from prepubertal Korean black goats
(Asian-Australasian Association of Animal Production Societies, 2018) S. Subi; S.J. Lee; S. Shiwani; N.K. Singh
Objective: Myogenic satellite cells were isolated from semitendinosus muscle of prepubertal Korean black goat to observe the differential effect of linolenic and retinoic acid in thepresence of thiazolidinediones (TZD) and also to observe the production insulin sensitive preadipocyte. Methods: Cells were characterized for their stemness with cluster of differentiation 34 (CD34), CD13, CD106, CD44, Vimentin surface markers using flow cytometry. Cells characterized themselves as possessing significant (p<0.05) levels of CD13, CD34, CD106, Vimentin revealing their stemness potential. Goat myogenic satellite cells also exhibited CD44, indicating that they possessed a % of stemness factors of adipose lineage apart from their inherent stemness of paxillin factors 3/7. Results: Cells during proliferation stayed absolutely and firmly within the myogenic fate without any external cues and continued to show a significant (p<0.05) fusion index % to express myogenic differentiation, myosin heavy chain, and smooth muscle actin in 2% horse serum. However, confluent myogenic satellite cells were the ones easily turning into adipogenic lineage. Intriguingly, upregulation in adipose specific genetic markers such as peroxisome proliferationactivated receptor ?, adiponectin, lipoprotein lipase, and CCAAT/ enhancer binding protein ? were observed and confirmed in all given treatments. However, the amount of adipogenesis was found to be statistically significant (p<0.01) with linolenic acid as compared to retinoic acid in combination with TZD’s. Conclusion: Retinoic acid was found to produce smaller preadipocytes which have been assumed to have insulin sensitization and hence retinoic acid could be used as a potential agent to sensitize tissues to insulin in combination with TZD’s to treat diabetic conditions in humans and animals in future. Copyright © 2018 by Asian-Australasian Journal of Animal Sciences.
Excited state proton transfer (ESIPT) based molecular probe to sense F- and CN- anions through a fluorescence "turn-on" response
(Royal Society of Chemistry, 2018) Rashid Ali; Ramesh C. Gupta; Sushil K. Dwivedi; Arvind Misra
A new chromogenic and fluorogenic hydrazone derivative of aminobenzthiazole and 2-hydroxy-1-naphthaldehyde was developed as a sensitive molecular probe, NTS, for the detection of fluoride (F-) and cyanide (CN-) anions. The photophysical and sensing behaviors of the probe, NTS, were investigated by absorption and fluorescence studies. Interestingly, in partial aqueous medium (DMSO/H2O 9:1, v/v), the probe shows a selective fluorescence "turn-on" response to both the anions. An excited state proton transfer mechanism (ESPT) has been followed theoretically and by means of spectroscopic studies. The immediate visualized color change of NTS with the respective anions on test paper strips and silica coated slides suggested the applicability of the probe to sense dual anions on solid surfaces and in solution as a chemosensor for fluoride and as a chemodosimeter for cyanide anions, respectively. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018.
Monoclinic to cubic phase transformation and photoluminescence properties in Hf1-xSmxO2 (x = 0-0.12) nanoparticles
(American Institute of Physics Inc., 2018) Sandeep Kumar; S.B. Rai; Chandana Rath
Bulk hafnium oxide (HfO2) exhibits the monoclinic phase at room temperature which transforms to tetragonal and cubic phases at 1700 and 2600 °C, respectively, under ambient conditions. For the first time, we observe a monoclinic to stable cubic phase transformation at room temperature in nanoparticles of HfO2 by incorporating Sm3+ ions up to 12 at. %. Although the monoclinic structure is retained at 1 at. % of Sm, a mixed phase of monoclinic and cubic is observed at intermediate Sm concentration (5-11 at. %). Le-Bail profile refinement of X-ray diffraction patterns confirms the monoclinic to cubic phase transformation with increasing Sm3+ ion concentration. While the significant difference in ionic radii of Sm3+ and Hf4+ ion induces strain in the lattice above 9 at. %, a lower valency of Sm produces oxygen vacancy leading to 8-fold coordination with Sm3+ ion and stabilizes the cubic phase at room temperature. Not only the particle size obtained from transmission electron micrograph (TEM) matches well with the size calculated from the Williamson-Hall plot, the lattice spacing estimated from high resolution TEM also confirms the monoclinic and cubic phases in HfO2 and Hf0.88Sm0.12O2, respectively. Apart from phase transformation induced by Sm3+ ions, photoluminescence studies demonstrate an excellent emission in near green and red regions in Hf1-xSmxO2 nanoparticles. A schematic energy band diagram has been proposed based on the excitation and emission processes involved in HfO2 and Hf0.99Sm0.01O2 nanoparticles. © 2018 Author(s).
Ozone pollution will compromise efforts to increase global wheat production
(Blackwell Publishing Ltd, 2018) Gina Mills; Katrina Sharps; David Simpson; Håkan Pleijel; Malin Broberg; Johan Uddling; Fernando Jaramillo; William J. Davies; Frank Dentener; Maurits Van den Berg; Madhoolika Agrawal; Shahibhushan B. Agrawal; Elizabeth A. Ainsworth; Patrick Büker; Lisa Emberson; Zhaozhong Feng; Harry Harmens; Felicity Hayes; Kazuhiko Kobayashi; Elena Paoletti; Rita Van Dingenen
Introduction of high-performing crop cultivars and crop/soil water management practices that increase the stomatal uptake of carbon dioxide and photosynthesis will be instrumental in realizing the United Nations Sustainable Development Goal (SDG) of achieving food security. To date, however, global assessments of how to increase crop yield have failed to consider the negative effects of tropospheric ozone, a gaseous pollutant that enters the leaf stomatal pores of plants along with carbon dioxide, and is increasing in concentration globally, particularly in rapidly developing countries. Earlier studies have simply estimated that the largest effects are in the areas with the highest ozone concentrations. Using a modelling method that accounts for the effects of soil moisture deficit and meteorological factors on the stomatal uptake of ozone, we show for the first time that ozone impacts on wheat yield are particularly large in humid rain-fed and irrigated areas of major wheat-producing countries (e.g. United States, France, India, China and Russia). Averaged over 2010–2012, we estimate that ozone reduces wheat yields by a mean 9.9% in the northern hemisphere and 6.2% in the southern hemisphere, corresponding to some 85 Tg (million tonnes) of lost grain. Total production losses in developing countries receiving Official Development Assistance are 50% higher than those in developed countries, potentially reducing the possibility of achieving UN SDG2. Crucially, our analysis shows that ozone could reduce the potential yield benefits of increasing irrigation usage in response to climate change because added irrigation increases the uptake and subsequent negative effects of the pollutant. We show that mitigation of air pollution in a changing climate could play a vital role in achieving the above-mentioned UN SDG, while also contributing to other SDGs related to human health and well-being, ecosystems and climate change. © 2018 The Authors. Global Change Biology Published by John Wiley & Sons Ltd
Preface
(Elsevier, 2018) Ashish Kumar Tewari; Supriya Tiwari
[No abstract available]
Study of heat and mass transport in Bénard-Darcy convection with g-jitter and variable viscosity liquids in a porous layer with internal heat source
(Isfahan University of Technology, 2018) A. Srivastava; B.S. Bhadauria; A.K. Singh
In this research article, we investigated the weakly non-linear effect of gravity modulation for the temperature dependent viscous fluid in a horizontal porous layer in the presence of internal heat source. We use power series expansion in terms of the amplitude of gravity modulation, which is considered to be small for double-diffusive convection in porous media. We graphically show the effect of internal heat source, solute Rayleigh number, Lewis number, Vadász number, thermo-rheological parameter, the amplitude of gravity modulation, the frequency of modulation on the heat and mass transfer using Ginzburg-Landau equation. The effect of gravity modulation is found significant and is more effective for the low values of frequency of modulation. © 2018, Isfahan University of Technology.
Household food insecurity and mental health among teenage girls living in urban slums in Varanasi, India: A cross-sectional study
(MDPI AG, 2018) Divya Rani; Jitendra Kumar Singh; Dilaram Acharya; Rajan Paudel; Kwan Lee; Shri Prakash Singh
This study was undertaken to investigate the relation between household food insecurity and mental health problems in teenage girls living in urban slums. This community-based cross-sectional study was conducted in 5 urban slums in Varanasi, India, between September 2016 and July 2017. A probability proportion to size (PPS) method was employed to select 5 of 210 urban slums at a first stage, and in the second stage, 418 teenage girls were chosen randomly from selected households. The Household Food Insecurity Access Scale (HFIAS) and mental health inventory tools were employed to assess food insecurity and mental health status. Multivariable logistic regression analysis with at a 95% confidence interval (CI) was used to assess the association between household food insecurity and mental health status. Of 418 respondents, 47.6% were food insecure; 64.1%, 57.7%, and 58.4% had high levels of anxiety, depression, or psychological distress, respectively; and 57.2% exhibited a medium level of loss of behavioral control. Furthermore, teenage girls from food insecure households were more likely to have high levels of anxiety, depression, loss of behavioral control and psychological distress than those living in food secure households. This study shows food insecurity is independently associated with mental health problems among teenage girls. Food insecurity in Indian slums should be addressed by specific public health intervention programs that provide access to sufficient safe, nutritious food. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
Mathematical modelling of Toxoplasma Gondii and host immune response
(American Institute of Physics Inc., 2018) Avinita Gautam; Anupam Priyadarshi
The study of incidence and distribution of health related events including disease, and control of disease are observed through Epidemiology. Toxoplasmosis is an omnipresent protozoan parasite that can infect all warm blood vertebrates, including mammals and birds. The infection is quite vast as approximately 20% human population in US and 30% world-wide are infected by this protozoan parasite. In this study, a mathematical model of interaction between Toxoplasma Gondii invasion dynamics and host immune responses is developed using system of ordinary differential equations. The analytic and numerical simulations are carried out to understand the dynamics and the impact of different functional responses. The Holling type II functional response enhances the effect or cells of host's immune response. However, it does not influence the reproduction number, force of infection and other parameters during the transient and steady-state of the disease infection. © 2018 Author(s).
Molecular profiling of foxtail millet (Setaria italica (L.) P. Beauv) from Central Himalayan Region for genetic variability and nutritional quality
(Cambridge University Press, 2018) A.K. Trivedi; L. Arya; S.K. Verma; R.K. Tyagi; A. Hemantaranjan; M. Verma; V.P. Sharma; D. Saha
Agriculture in the Central Himalayan Region depends on the availability of suitable germplasm as well as natural conditions. Due to extreme weather conditions, food and nutrition security is a major issue for communities inhabiting these remote and inaccessible areas. Millets are common crops grown in these areas. Foxtail millet (Setaria italica (L.) P. Beauv) is an important crop and forms a considerable part of the diet in this region. The aim of the present study was to explore, collect, conserve and evaluate the untapped genetic diversity of foxtail millet at the molecular level and discover variability in their nutritional traits. A total of 30 accessions having unique traits of agronomic importance were collected and molecular profiling was performed. A total of 63 alleles were generated with an average of 2.52 alleles per locus and average expected heterozygosity of 0.37 ± 0.231. Significant genetic variability was revealed through the genetic differentiation (Fst) and gene flow (Nm) values. Structure-based analysis divided whole germplasm into three sub-groups. Rich variability was found in nutritional traits such as dietary fibre in husked grains, carbohydrate, protein, lysine and thiamine content. The collected germplasm may be useful for developing nutritionally rich and agronomically beneficial varieties of foxtail millet and also designing strategies for utilization of unexploited genetic diversity for food and nutrition security in this and other similar agro-ecological regions. © 2018 Cambridge University Press.
Cadmium induced physio-chemical changes in roots of wheat
(Springer, 2018) Anaytullah Siddique; Anand Prakash Dubey; Prasann Kumar
Cadmium (Cd 2+ ) is a highly toxic biologically non-essential heavy metal which adversely affects the growth, development and yield of plants. Therefore, the study was undertaken to assess the effects of different concentrations of CdCl 2 (25, 50, 75 and 100 ppm) on physiological and biochemical changes occur during initial growth phases. The accumulation of heavy metal cadmium (Cd 2+ ) in roots of wheat seedling, level of toxicity and their effect on wheat seedling was measured by measuring / estimating the % inhibition of germination, length of root, shoot (cm), root/shoot ratio, seed vigour index (SVI), phytotoxicity (%), tolerance index (T. I. %), relative water content (RWC%) chlorophyll content (mg g -1 ), proline content (µg g -1 ) and superoxide dismutase (SOD, unit×10 2 g -1 f. wt. min -1 ). As the externally imposed elevated levels of CdCl 2 increased towards 25 to 100 ppm the cadmium (Cd 2+ ) concentration increased in roots in the same proportion. The effect of (Cd 2+ ) uptake by root was appeared on reduction of % inhibition of germination, length of root, shoot (cm), root/shoot ratio, T.I.(%), RWC(%), and Chlorophyll content (mg g -1 ). While the phytotoxicity (%), proline content (µg g -1 ) and superoxide dismutase (SOD, unit×10 2 g -1 f. wt. min -1 ) were found to be increased in wheat seedling at 240 hours of old wheat seedling in comparison to control (Without treated set). © 2018, SPR, All Rights Reserved.
Tolerance strategies in cyanobacterium Fischerella sp. under pesticide stress and possible role of a carbohydrate-binding protein in the metabolism of methyl parathion (MP)
(Elsevier Ltd, 2018) Balkrishna Tiwari; Ekta Verma; Sindhunath Chakraborty; Alok Kumar Srivastava; Arun Kumar Mishra
The tolerance strategy of cyanobacterium Fischerella sp. under methyl parathion (MP) stress was investigated through proteomics analysis using 2-DE technique coupled with MALDI- TOF MS/MS. Proteomic study of the cyanobacterium treated with or without MP for two and eight days exhibited differential expressions of proteins related to photosynthesis, energy and protein metabolism, redox homeostasis, signal transduction and cellular defence. Inhibitory effect of MP on the growth of the test organism was more pronounced after the 2nd day of treatment and the majority of the proteins, except those involved in the protein metabolism (DnaK, Ef-Tu and proteases), were downregulated. However, the growth of the cyanobacterium was significantly less affected after the 8th day of MP treatment and a number of proteins, viz., antioxidative enzymes, signalling protein, chaperones, were induced. Transcript analyses of the genes of few upregulated and downregulated proteins, i.e., phycocyanin α subunit (cpcA), ribulose bisphosphate carboxylase (rbcl), F0F1 ATP synthase subunit α, F0F1 ATP synthase subunit β, SOD (sod), NifH (nif H), DnaK (dnaK) and Peptidase S8 showed similar results after the 8th day of MP treatment. Furthermore, some hypothetical proteins were also found to be upregulated in the cyanobacterium under MP stress. Functional prediction of four of these hypothetical proteins using bioinformatic tools revealed their roles in signalling and carbohydrate metabolism. Interestingly, one hypothetical protein was homologous to lectin and found to possess a binding pocket for MP. Therefore, this lectin-type protein of the cyanobacterium might have a crucial role in the removal and degradation of MP. © 2017 Elsevier Ltd
Reactive Oxygen Defense Against Cellular Endoparasites and the Origin of Eukaryotes
(Elsevier, 2018) James F. White; Kathryn Kingsley; Carla J. Harper; Satish K. Verma; Lara Brindisi; Qiang Chen; Xiaoqian Chang; April Micci; Marshall Bergen
In this chapter, we propose a model for the early evolution of eukaryotic cells under pressure of intense endoparasitism. We define features of eukaryotes developed to defend against endoparasites (primarily bacteria), including a defensive system composed of an antioxidant sterol-enriched internal and external membrane system that could be used to entrap endoparasites and degrade them with superoxide produced on the membranes, cytoskeleton scaffolding for the membrane system, and a nuclear envelope to exclude endoparasites from reaching the genome. Mitochondria and chloroplasts evolved from the prokaryotes that developed ways to neutralize the reactive oxygen defense of the host. For mitochondria, hydrogen pumping to the exterior of the endoparasite enabled them to reduce superoxide to water, effectively defeating the host defense. Other features of eukaryotes that may have evolved from defense from endoparasitism include: autophagy, cell walls in fungi and plants, acquired immunity in animals, multicellularity, and apoptosis. We evaluate fossil data, where available, to provide additional information regarding the early evolution of eukaryotes and the prevalence of endoparasitic microbes. © 2018 Elsevier Inc. All rights reserved.
Effect of laser irradiation on micro-hardness, compactness and Raman spectrum of glassy Se76Te20Sn2Cd2 alloy
(Elsevier Editora Ltda, 2018) Amit Kumar; Mousa M.A. Imran; Arvind Sharma; Neeraj Mehta
In present novel work, we have synthesized a novel quaternary Se76Te20Sn2Cd2 glass in bulk form. Four laser light sources from UV-Vis-IR region have been used to investigate the laser-induced effects on the micro-hardness to check the candidature of this material for possible application in fiber optics. The micro-hardness of the quaternary Se76Te20Sn2Cd2 glass is increased appreciably after laser exposure. This result has been analyzed in terms of compactness. The enhancement in both micro-hardness and compactness is also explained by Raman spectroscopy. © 2017 Brazilian Metallurgical, Materials and Mining Association
Compositionality versus non-compositionality verification based on lexical domain for verbal phraseological units
(IOS Press, 2018) Belém Priego Sánchez; David Pinto; Vivek Kumar Singh
A Verbal Phraseological Unit (VPU) is a phrase or expression that has either a literal or figurative (noncompositional) meaning. Identifying, in an automatic manner, which meaning is associated to a VPU in a certain context is an open problem in natural language processing, whose solution impacts in various real life applications. In this paper we present a method for the automatic verification of non-compositionality of a VPU based on the use of lexical domains. The methodology proposed is based in the degree of overlapping between the VPU domain and its context domain. This methdology is general in the sense that it opens the opportunity of applying different overlapping metrics, and different methods for calculating the domain of a given phrase. The experiments carried out show that this novel approach can be efficiently applied in high volumes of data with competitive results close to 65%. © 2018-IOS Press and the authors. All rights reserved.
Super periodic potential
(Academic Press Inc., 2018) Mohammd Hasan; Bhabani Prasad Mandal
In this paper we introduce the concept of super periodic potential (SPP) of arbitrary order n, n∈I+, in one dimension. General theory of wave propagation through SPP of order n is presented and the reflection and transmission coefficients are derived in their closed analytical form by transfer matrix formulation. We present scattering features of super periodic rectangular potential and super periodic delta potential as special cases of SPP. It is found that the symmetric self-similarity is the special case of super periodicity. Thus by identifying a symmetric fractal potential as special cases of SPP, one can obtain the tunnelling amplitude for a particle from such fractal potential. By using the formalism of SPP we obtain the close form expression of tunnelling amplitude of a particle for general Cantor and Smith–Volterra–Cantor potentials. © 2018 Elsevier Inc.