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.

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>

Doubled haploid breeding- a potential strategy for development of high yielding drought tolerant genotypes in Upland rice

Tripathy Swapan K.,Maharana Manasmita 한국작물학회 2024 Journal of crop science and biotechnology Vol.27 No.4

Doubled haploid breeding using anther culture is potentially acclaimed for early fixation of homozygosity. We recovered 129 androgenic doubled haploid lines (DHLs) from a cross Khandagiri (drought sensitive) x Dular (drought tolerant). Fifty five DHLs with high seedling vigour showed wide variability for traits associated with drought tolerance and seed yield under drought stress. DHL 1, DHL 4, DHL 8, DHL 24, DHL 30, DHL 41, DHL 43, DHL 48 and DHL 53 showed higher degree of drought tolerance and also revealed the drought tolerant allele (126 bp) amplified by SSR marker RM 8085. DHL41, DHL 53, DHL43, DHL4 and DHL24 had high yield potential than Sahbhagidhan. However, DHL 41 being a short duration (90 days) and semi-dwarf (101.9 cm) with significantly higher number of grains/panicle, very high 1000-grain weight (28.9 g), fertility percentage (94.2%) and seed yield (46.6 q/ha); can be fitted to upland condition. Besides, the DHLs can serve as an ideal mapping population for mapping and detection of QTLs/genes of interest in upland rice.

Morphological and Molecular Characterization of Endangered Medicinal Plant Species Coleus forskohlii Collected from Central India

Tripathi, Niraj,Saini, Navinder,Tiwari, Sharad 한국작물학회 2013 Journal of crop science and biotechnology Vol.16 No.4

In recent years, Coleus forskohlii has been considered plant as an important medicinal. Because of the continuous collection of roots from the wild sources, this plant has been included in the list of endangered species. This has necessitated the use of biotechnology in conservation and sustainable management of this endangered plant species. Morphological and molecular characterization of this herb will enhance our understanding in improving the optimal yields of Forskolin through breeding. To assess the morphological and molecular genetic diversity in 18 C. forskohlii genotypes collected from different places of central India, RAPD, ISSR, and AFLP marker systems were employed. Eleven RAPD, ten ISSRs and eight AFLP primers produced 101, 80, and 483 fragments, respectively. Among the three marker system used in this study, RAPD and ISSR showed 61.39 and 68.75% polymorphism, respectively, while eight AFLP primer combinations produced 70.81% polymorphism. UPGMA cluster analysis method group genotypes in two clusters with all marker systems separately and after combined analysis. Results show that both morphological and molecular factors are effective in observing variations. Our results also indicate that the RAPD, ISSR, and AFLP approaches, along with pharmaceutically important morphological trait analysis, seemed to be best-suited for assessing the genetic relationships among distinct C. Forskohlii genotypes with high accuracy.

Tropical Soil Bacterial Communities in Malaysia: pH Dominates in the Equatorial Tropics Too

Tripathi, Binu M.,Kim, Mincheol,Singh, Dharmesh,Lee-Cruz, Larisa,Lai-Hoe, Ang,Ainuddin, A. N.,Go, Rusea,Rahim, Raha Abdul,Husni, M. H. A.,Chun, Jongsik,Adams, Jonathan M. Springer-Verlag 2012 Microbial ecology Vol.64 No.2

The predictability of the extratropical stratosphere on monthly time‐scales and its impact on the skill of tropospheric forecasts

Tripathi, Om P.,Baldwin, Mark,Charlton‐,Perez, Andrew,Charron, Martin,Eckermann, Stephen D.,Gerber, Edwin,Harrison, R. Giles,Jackson, David R.,Kim, Baek‐,Min,Kuroda, Yuhji,Lang, Andrea,Mah John WileySons, Ltd 2015 Quarterly journal of the Royal Meteorological Soci Vol.141 No.689

<P>Extreme variability of the winter‐ and spring‐time stratospheric polar vortex has been shown to affect extratropical tropospheric weather. Therefore, reducing stratospheric forecast error may be one way to improve the skill of tropospheric weather forecasts. In this review, the basis for this idea is examined. A range of studies of different stratospheric extreme vortex events shows that they can be skilfully forecasted beyond 5 days and into the sub‐seasonal range (0–30 days) in some cases. Separate studies show that typical errors in forecasting a stratospheric extreme vortex event can alter tropospheric forecast skill by 5–7% in the extratropics on sub‐seasonal time‐scales. Thus understanding what limits stratospheric predictability is of significant interest to operational forecasting centres. Both limitations in forecasting tropospheric planetary waves and stratospheric model biases have been shown to be important in this context.</P>

Graphene Coating via Chemical Vapor Deposition for Improving Friction and Wear of Gray Cast Iron at Interfaces

Tripathi, Khagendra,Gyawali, Gobinda,Lee, Soo Wohn American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.37

<P>This study reports the influence of CVD-graphene on the tribological performance of gray cast iron (GCI) from the internal combustion engine (ICE) cylinder liners by performing a ball-on-disk friction tests. The graphene-coated specimen exhibited a significant reduction (similar to 53%) of friction as compared to that of the uncoated specimen, whereas wear resistance increased by 2- and 5-fold regarding the wear of specimen and ball, respectively. Extremely low shear strength and highly lubricating nature of graphene contribute to the formation of a lubricative film between the sliding surfaces and decreases the interaction between surfaces in the dry environment. Under the applied load, a uniform film of iron oxides such as Fe2O3, Fe3O4, and FeOOH is found to be formed between the surfaces. It is proposed that the graphene encapsulation with the metal debris and oxides formed between the specimens increases the lubricity and decreases the shear force. The transformation of graphene/graphite into nanocrystalline graphites across the contact interfaces following the amorphization trajectory further increases the lubricity of the film that ultimately reduces friction and wear of the material.</P>

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>

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