Concentration Dependent Optical Properties of Rhodamine B Doped Poly(vinyl alcohol) Solutions

Jitendra Tripathi,Anupam Sharma,Shilpa Tripathi,Kallol Kumar Das 한국고분자학회 2016 Macromolecular Research Vol.24 No.7

The optical properties, namely refractive index (RI) studies, are reported on a series of pure and doped poly(vinyl alcohol) (PVA) in solution form. The PVA solutions were synthesized with 1, 2, 3, 4, and 5 wt% of PVA in distilled water followed by doping with Rhodamine B in concentrations ranging from 0.05 wt% to 2 wt%. The absorption spectra show an observable shift in the band edge position towards higher wavelength with increase in PVA wt%. When the dopant molecules are added, the curves are drastically modified with the occurrence of new peaks arising at higher doping concentrations along with change in the bandgap. These effects are prominent for all the concentration of PVA solution. The RI does not change much for low doping wt%. but when dopant is added in higher concentrations, it increases slightly reaching a maximum of ~1.35 at 2 wt%. It is observed that host polymer properties dominate at low doping while a combination of host polymer and dopant dye properties dominate at higher doping concentrations.

Tales from Fragments: A Review of Indian Human Skeletal Studies

Veena Mushrif-Tripathy 대한체질인류학회 2019 해부·생물인류학 (Anat Biol Anthropol) Vol.32 No.2

India provides large number of skeletal data from the pre- and protohistoric levels covering a time span of almost 10,000 years. Major skeletal collection comes from the cultural phases ranging from the Mesolithic, Harappan, Neolithic, Chalcolithic and Iron Age levels. After the Early Historic phase cremation became the most common method for disposing the dead. Though the relevant documentation is far less than complete, recovery of human burials has been reported from more than 300 sites (Mushrif-Tripathy et al. 2016) and a conservative estimate would lead to imagine approximately 2000 human skeletons. The human skeletal analysis started around 1950s and initial focus of the study was to understand the racial classification of the skulls and to prove the Indo-Aryan invasion theory. Later from 1980s multidisplinary approach including socio-cultural anthropology, growth and nutrition and medical anthropology were considered. The recent development includes the use of new scientific methods like isotope, aDNA, DXA scans, and Scanning Electron Microscope studies etc. are consider to understand ancient inhabitants of Indian Sub-continent.

Synergy Effect of Ultrasonic Nanocrystalline Surface Modification and Laser Surface Texturing on Friction and Wear Behavior of Graphite Cast Iron

Tripathi, Khagendra,Gyawali, Gobinda,Amanov, Auezhan,Lee, Soo W. unknown 2017 Tribology transactions Vol.60 No.2

Examining the Predictability of the Stratospheric Sudden Warming of January 2013 Using Multiple NWP Systems

Tripathi, Om P.,Baldwin, Mark,Charlton-Perez, Andrew,Charron, Martin,Cheung, Jacob C. H.,Eckermann, Stephen D.,Gerber, Edwin,Jackson, David R.,Kuroda, Yuhji,Lang, Andrea AMERICAN METEOROLOGICAL SOCIETY 2016 Monthly weather review Vol.144 No.5

<P>The first multimodel study to estimate the predictability of a boreal sudden stratospheric warming (SSW) is performed using five NWP systems. During the 2012/13 boreal winter, anomalous upward propagating planetary wave activity was observed toward the end of December, which was followed by a rapid deceleration of the westerly circulation around 2 January 2013, and on 7 January 2013 the zonal-mean zonal wind at 608N and 10 hPa reversed to easterly. This stratospheric dynamical activity was followed by an equatorward shift of the tropospheric jet stream and by a high pressure anomaly over the North Atlantic, which resulted in severe cold conditions in the United Kingdom and northern Europe. In most of the five models, the SSW event was predicted 10 days in advance. However, only some ensemble members in most of the models predicted weakening of westerly wind when the models were initialized 15 days in advance of the SSW. Further dynamical analysis of the SSW shows that this event was characterized by the anomalous planetary wavenumber-1 amplification followed by the anomalous wavenumber-2 amplification in the stratosphere, which resulted in a split vortex occurring between 6 and 8 January 2013. The models have some success in reproducing wavenumber-1 activity when initialized 15 days in advance, but they generally failed to produce the wavenumber-2 activity during the final days of the event. Detailed analysis shows that models have reasonably good skill in forecasting tropospheric blocking features that stimulate wavenumber-2 amplification in the troposphere, but they have limited skill in reproducing wavenumber-2 amplification in the stratosphere.</P>

Mesoporous ZnO nanoclusters as an ultra-active photocatalyst

Tripathy, N.,Ahmad, R.,Kuk, H.,Hahn, Y.B.,Khang, G. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.8

Morphology modulation of nanostructured materials are highly crucial for various applications including photocatalysis, drug delivery, etc. In this study, mesoporous zinc oxide (ZnO) nanoclusters (MZN) were synthesized via a simple, cost-effective, low-temperature wet chemical route and further sucessfully utilized for photodegradation of Rhodamine B (RhB). Firstly, polystyrene (PS) nanospheres (~300nm) were prepared by polymerization of styrene in aqueous solvent. Then the MZN were achieved by formation of ZnO nanoparticles-shell over the surface of PS nanospheres via esterification of zinc acetate dihydrate in isopropyl alcohol followed by toluene dissolution of PS core. The as-synthesized MZN were spherically-shaped, porous in nature with a diameter of ~ 400nm and composed of well-arranged highly-crystalline ZnO nanoparticles (~ 5nm). The MZN also exhibited a high surface area of 78.3+/-5.4m<SUP>2</SUP>g<SUP>-1</SUP> and an average pore diameter of ~26nm. Furthermore, this unique structure demonstrates an expeditious photodegradation of RhB under UV illumination, monitored by UV-visible spectroscopy at different time intervals until the dye was completely degraded to colorless end products. Fast RhB decomposition was observed with a degradation rate of ~98% within initial 40min which can be attributed to the porous nature, large specific surface area and excellent electron accepting features of the engineered nanoclusters.

A Study on the Effect of Laser Surface Texturing on Friction and Wear Behavior of Graphite Cast Iron

Tripathi, Khagendra,Joshi, Bhupendra,Gyawali, Gobinda,Amanov, Auezhan,Lee, Soo Wohn ASME International 2016 Journal of tribology Vol.138 No.1

Soil pH mediates the balance between stochastic and deterministic assembly of bacteria

Tripathi, Binu M.,Stegen, James C.,Kim, Mincheol,Dong, Ke,Adams, Jonathan M.,Lee, Yoo Kyung Nature Publishing Group UK 2018 The ISME journal Vol.12 No.4

<P>Little is known about the factors affecting the relative influences of stochastic and deterministic processes that govern the assembly of microbial communities in successional soils. Here, we conducted a meta-analysis of bacterial communities using six different successional soil datasets distributed across different regions. Different relationships between pH and successional age across these datasets allowed us to separate the influences of successional age (i.e., time) from soil pH. We found that extreme acidic or alkaline pH conditions lead to assembly of phylogenetically more clustered bacterial communities through deterministic processes, whereas pH conditions close to neutral lead to phylogenetically less clustered bacterial communities with more stochasticity. We suggest that the influence of pH, rather than successional age, is the main driving force in producing trends in phylogenetic assembly of bacteria, and that pH also influences the relative balance of stochastic and deterministic processes along successional soils. Given that pH had a much stronger association with community assembly than did successional age, we evaluated whether the inferred influence of pH was maintained when studying globally distributed samples collected without regard for successional age. This dataset confirmed the strong influence of pH, suggesting that the influence of soil pH on community assembly processes occurs globally. Extreme pH conditions likely exert more stringent limits on survival and fitness, imposing strong selective pressures through ecological and evolutionary time. Taken together, these findings suggest that the degree to which stochastic vs. deterministic processes shape soil bacterial community assembly is a consequence of soil pH rather than successional age.</P>

ON N(k)-QUASI EINSTEIN MANIFOLDS

Tripathi, Mukut Mani,Kim, Jeong-Sik Korean Mathematical Society 2007 대한수학회논문집 Vol.22 No.3

N(k)-quasi Einstein manifolds are introduced and studied.

Metal-induced redshift of optical spectra of gold nanoparticles: An instant, sensitive, and selective visual detection of lead ions

Tripathi, R.M.,Park, Sun Hee,Kim, Gahyeon,Kim, Do-Hwi,Ahn, Dohee,Kim, Yeong Mok,Kwon, Se Jeong,Yoon, Sun-Young,Kang, Hyo Jin,Chung, Sang J. Elsevier 2019 INTERNATIONAL BIODETERIORATION AND BIODEGRADATION Vol.144 No.-

<P><B>Abstract</B></P> <P>Environmental exposure to non-essential lead has become a serious problem in various developing and industrializing countries. There is an urgent need to develop a method offering instrument-free, rapid, highly sensitive, and selective detection of lead. Colorimetric detection of lead using gold nanoparticles (AuNPs) has been reported but these NPs require specific surface modifications and incubation times. In this study, we have developed an approach for instant, highly selective and sensitive detection of Pb<SUP>2+</SUP>. The as-synthesized AuNPs did not require any surface modification for the detection of Pb<SUP>2+</SUP>. The selectivity was evaluated by taking 300 μM of various metal ions and the assay color was found to change rapidly from red to blue in the presence of Pb<SUP>2+</SUP>, whereas the color remained the same for the other metal ions. The present method did not require a long incubation time as the assay color changed as soon as the AuNPs were added into the Pb<SUP>2+</SUP> solution. Therefore, the developed method realized rapid detection of Pb<SUP>2+</SUP>. The limit of detection and limit of quantification were calculated to be 18 μM and 53.5 μM, respectively. The detection mechanism was investigated using ultraviolet–visible spectroscopy, dynamic light scattering, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The as-synthesized nanoparticles were used for the detection of Pb<SUP>2+</SUP>. </LI> <LI> Incubation with sample was not required as the method showed an ultra-rapid response. </LI> <LI> The LOD and LOQ were calculated to be 18 μM and 53.5 μM, respectively. </LI> <LI> The carboxylic group ligands governed the interaction between the AuNPs and Pb<SUP>2+</SUP>. </LI> <LI> A700/528 ratio shows Pb<SUP>2+</SUP> in highest aggregation but other metals similar to blank. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Extracellular ATP Acts on Jasmonate Signaling to Reinforce Plant Defense

Tripathi, Diwaker,Zhang, Tong,Koo, Abraham J.,Stacey, Gary,Tanaka, Kiwamu American Society of Plant Biologists 2018 Plant Physiology Vol.176 No.1

<P>Extracellular ATP signaling, mediated by the P2K1 receptor, directly changes the stability of JAZ1 protein in JA signaling to boost plant defense response.</P><P>Damaged cells send various signals to stimulate defense responses. Recent identification and genetic studies of the plant purinoceptor, P2K1 (also known as DORN1), have demonstrated that extracellular ATP is a signal involved in plant stress responses, including wounding, perhaps to evoke plant defense. However, it remains largely unknown how extracellular ATP induces plant defense responses. Here, we demonstrate that extracellular ATP induces plant defense mediated through activation of the intracellular signaling of jasmonate (JA), a well-characterized defense hormone. In Arabidopsis (<I>Arabidopsis thaliana</I>) leaves, ATP pretreatment induced resistance against the necrotrophic fungus, <I>Botrytis cinerea</I>. The induced resistance was enhanced in the P2K1 receptor overexpression line, but reduced in the receptor mutant, <I>dorn1</I>-<I>3</I>. Mining the transcriptome data revealed that ATP induces a set of JA-induced genes. In addition, the P2K1-associated coexpression network contains defense-related genes, including those encoding jasmonate ZIM-domain (JAZ) proteins, which play key roles as repressors of JA signaling. We examined whether extracellular ATP impacts the stability of JAZ1 in Arabidopsis. The results showed that the JAZ1 stability decreased in response to ATP addition in a proteasome-dependent manner. This reduction required intracellular signaling via second messengers—cytosolic calcium, reactive oxygen species, and nitric oxide. Interestingly, the ATP-induced JAZ1 degradation was attenuated in the JA receptor mutant, <I>coi1</I>, but not in the JA biosynthesis mutant, <I>aos</I>, or upon addition of JA biosynthesis inhibitors. Immunoprecipitation analysis demonstrated that ATP increases the interaction between COI1 and JAZ1, suggesting direct cross talk between extracellular ATP and JA in intracellular signaling events. Taken together, these results suggest that extracellular ATP signaling directly impacts the JA signaling pathway to maximize plant defense responses.</P>