Synthesis and characterization of ZnGa2O4:Cr3+Ge3+ compounds with tunable photoluminescence properties

Kumar Pankaj,Sharma Aditya,Bishnoi Priyanka,Vij Ankush,Kumar Sandeep,Shin Hyun-Joon,Chae K. H.,Lee B. H.,Won S. O. 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.83 No.6

Pure and doped (Cr and Ge) ZnGa2O4 compounds are prepared using solid-state reaction method. Single-phase nature of pure and doped ZnGa2O4 compounds is investigated using X-ray difraction (XRD). XRD results indicate lower theta angle shifting, decrease in particle size and tensile strain in the doped samples. A granular morphology of amalgamated particles is seen in the SEM images. EDS results convey, practically, the same concentrations (atm%) of doped elements as used during the preparation. X-ray absorption near-edge structure (XANES) results helped to determine the valence state of elements. O K-edge XANES shows a signifcant orbital hybridization of O 2p shells with the d shells of doped atoms (i.e., Cr and Ge). Broad PL bands, of nearly the white-light emission, are observed in all of the samples. Modifcation in the PL intensity and emitted wavelengths, upon doping of Cr3+ and Ge3+ ions, are discussed through the energy transfer mechanisms and defects in the compounds.

Recent advances and remaining challenges for polymeric nanocomposites in healthcare applications

Kumar, Sandeep,Sarita, Sandeep,Nehra, Monika,Dilbaghi, Neeraj,Tankeshwar, K.,Kim, Ki-Hyun Elsevier 2018 Progress in polymer science Vol.80 No.-

<P><B>Abstract</B></P> <P>Remarkable advancements in material technologies have accelerated the use of many new materials and their hybrids and composites in diverse applications. Among such available options, polymer nanocomposites are recognized to have the potential to bring future revolution, especially because of their flexible functionalities and related advantages (e.g., good strength, large surface area to volume ratio, large flame retardancy, high elastic modulus, enhanced density, and thermo-mechanical/optoelectronic/magnetic properties). These nanocomposites have been successfully incorporated into diverse fields of applications such as drug delivery, tissue engineering, gene therapy, food preservation, biosensing, and bioimaging. Thus, the primary focus of this review is placed to give an integrated overview of polymer nanocomposites along with their synthesis routes, surface treatment strategies, and applications in the healthcare sector (e.g., drug delivery, 3D bio-implant, bioimaging, food processing, and other miscellaneous biomedical applications). Our discussion also highlights future directions for this emerging field of research.</P>

Synthesis and characterization of nanocrystalline Al_0.5Ag_0.5TiO₃ powder

Kumar, Sandeep,Sahay, L.K.,Jha, Anal K.,Prasad, K. Techno-Press 2013 Advances in nano research Vol.1 No.4

A low-cost, green and reproducible citric acid assisted synthesis of nanocrystalline $Al_{0.5}Ag_{0.5}TiO_3$ (n-AAT) powder is reported. X-ray, FTIR, energy dispersive X-ray, transmission electron microscopy and scanning electron microscopy analyses are performed to ascertain the formation of n-AAT. X-ray diffraction data analysis indicated the formation of monoclinic structure. Spherical shaped particles having the sizes of 3-15 nm are found. The mechanism of nano-transformation for the soft-chemical synthesis of n-AAT has been explained using simple organic chemistry rules and nucleation and growth theory. Dielectric study revealed that AAT ceramic might be a suitable candidate for capacitor applications.

Rapid Prediction of Deflections in Multi-span Continuous Composite Bridges using Neural Networks

R. K. Gupta,Sushil Kumar,K. A. Patel,Sandeep Chaudhary,A.K. Nagpal 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.4

This paper proposes closed form expressions for the rapid prediction of deflections in steel-concrete composite bridges of large number of spans subjected to service load. The proposed expressions take into account shear lag effect, flexibility of shear connectors and cracking in concrete slabs. Three separate neural networks have been developed for right exterior span, left exterior span and interior spans. The closed form expressions have been obtained from the neural networks developed in the study. The training, validating and testing data sets for the neural networks are generated using finite element software ABAQUS. The proposed expressions have been validated for number of bridges and the errors are found to be small for practical purposes. Sensitivity studies have been carried out using the proposed expressions to evaluate the suitability of input parameters. The use of the proposed expressions requires a computational effort that is fraction of that required for the finite element analysis, therefore, can be used for rapid prediction of deflection for everyday design.

Serum albumin is the strongest predictor of anti-tumor necrosis factor nonresponse in inflammatory bowel disease in resource-constrained regions lacking therapeutic drug monitoring

Peeyush Kumar,Sudheer K. Vuyyuru,Prasenjit Das,Bhaskar Kante,Mukesh Kumar Ranjan,David Mathew Thomas,Sandeep Mundhra,Pabitra Sahu,Pratap Mouli Venigalla,Saransh Jain,Sandeep Goyal,Rithvik Golla,Shubi 대한장연구학회 2023 Intestinal Research Vol.21 No.4

Background/Aims: Evidence on predictors of primary nonresponse (PNR), and secondary loss of response (SLR) to anti-tumor necrosis factor (anti-TNF) agents in inflammatory bowel disease is scarce from Asia. We evaluated clinical/biochemical/molecular markers of PNR/SLR in ulcerative colitis (UC) and Crohn’s disease (CD).Methods: Inflammatory bowel disease patients treated with anti-TNF agents (January 2005–October 2020) were ambispectively included. Data concerning clinical and biochemical predictors was retrieved from a prospectively maintained database. Immunohistochemistry for expression of oncostatin M (OSM), OSM receptor (OSM-R), and interleukin-7 receptor (IL-7R) were done on pre anti-TNF initiation mucosal biopsies.Results: One-hundred eighty-six patients (118 CD, 68 UC: mean age, 34.1±13.7 years; median disease duration at anti-TNF initiation, 60 months; interquartile range, 28–100.5 months) were included. PNR was seen in 17% and 26.5% and SLR in 47% and 28% CD and UC patients, respectively. In CD, predictors of PNR were low albumin (<i>P</i><0.001), postoperative recurrence (<i>P</i>=0.001) and high IL-7R expression (<i>P</i><0.027) on univariate; and low albumin alone (hazard ratio [HR], 0.09; 95% confidence interval [CI], 0.03–0.28; <i>P</i><0.001) on multivariate analysis respectively. Low albumin (HR, 0.31; 95% CI, 0.15–0.62; <i>P</i>=0.001) also predicted SLR. In UC, predictors of PNR were low albumin (<i>P</i><0.001), and high C-reactive protein (<i>P</i><0.001), OSM (<i>P</i><0.04) and OSM-R (P=0.07) stromal expression on univariate; and low albumin alone (HR, 0.11; 95% CI, 0.03–0.39; <i>P</i>=0.001) on multivariate analysis respectively. Conclusions: Low serum albumin at baseline significantly predicted PNR in UC and PNR/SLR in CD patients. Mucosal markers of PNR were high stromal OSM/OSM-R in UC and high IL-7R in CD patients.

Genetic Structure and Differentiation of Three Indian Goat Breeds

Dixit, S.P.,Verma, N.K.,Aggarwal, R.A.K.,Kumar, Sandeep,Chander, Ramesh,Vyas, M.K.,Singh, K.P. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.9

Gene flow, genetic structure and differentiation of Kutchi, Mehsana and Sirohi breeds of goat from North-Western India were evaluated based on 25 microsatellite markers so as to support breed conservation and improvement decisions. The microsatellite genotyping was carried out using an automated DNA sequencer. The gene diversity across the studied loci for the Kutchi breed varied from 0.57 (ILST 065) to 0.93 (OarFCB 304, OMHC 1, ILSTS 058) with an overall mean of 0.79${\pm}$0.02. The corresponding values for Mehsana and Sirohi breeds were 0.16 (ILST 008) to 0.93 (OMHC 1, ILSTS 058) with an average of 0.76${\pm}$0.04, and 0.50 (ILSTS 029) to 0.94 (ILSTS 058) with an average of 0.78${\pm}$0.02, respectively. The Mehsana breed had lowest gene diversity among the 3 breeds studied. All the populations showed an overall significant heterozygote deficit ($F_{is}$). The Fis values were 0.26, 0.14 and 0.36 for Kutchi, Mehsana and Sirohi goat breeds, respectively. Kutchi and Mehsana were more differentiated (16%) followed by Mehsana and Sirohi (13%).The measures of standard genetic distance between pairs of breeds indicated that the lowest genetic distance was between Kutchi and Sirohi breeds (0.73) and the largest genetic distance was between Mehsana and Kutchi (1.0) followed by Sirohi and Mehsana (0.75) breeds. Mehsana and Kutchi are distinct breeds and this was revealed by the estimated genetic distance between them. All measures of genetic variation revealed substantial genetic variation in each of the populations studied, thereby showing good scope for their further improvement.

Improving Analytical Performance of Laser-induced Breakdown Spectroscopy for Strontium, the Minor Impurity Element, in Salts Using Multiple Filter-Paper Sampling

Kumar Sandeep,Ngo Van Tho,Park Jeong,Ham Kyung‐Sik,Singh Vivek K.,Nam Sang‐Ho,Lee Yonghoon 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.5

Strontium (Sr) is an element of toxicological concern due to its close chemical proximity to Ca. In this work, Sr in sea salts collected from China and South Korea was analyzed by laser-induced breakdown spectroscopy (LIBS). The precision could be improved by using multiple filter-paper sampling and intensity normalization using a weak Na I line as a reference signal. The analyte signal variation between filter-paper pieces as well as that within a single filter-paper piece could be corrected by the suggested method. The limit of detection of ~2 ppm and the precision of ~5% could be obtained. As a measure of accuracy, the root-mean-square error was estimated to be 9 ppm. The multiple filter-paper sampling can be performed easily on the salt production sites and improves the LIBS analysis precision resulting to sufficient quantification capability for minor metallic elements in edible sea salt products.

Carbon nanotubes: a novel material for multifaceted applications in human healthcare

Kumar, Sandeep,Rani, Ruma,Dilbaghi, Neeraj,Tankeshwar, K.,Kim, Ki-Hyun The Royal Society of Chemistry 2017 Chemical Society reviews Vol.46 No.1

<P>Remarkable advances have been achieved in modern material technology, especially in device fabrication, and these have facilitated the use of diverse materials in various applications. Carbon nanotubes (CNTs) are being successfully implemented in drug delivery, sensing, water purification, composite materials, and bone scaffolds. Thus, CNTs must meet a wide range of criteria such as surface modification, high aspect ratio, desired conductivity, high porosity and loading, non-toxicity, specificity, and selectivity, and compatibility for device fabrication. The main focus of this review is to explore the maximum applications of CNTs for human health, and we particularly focus on nanocarrier and biomedical applications. The scope of this review initially covers the basic aspects of CNTs and is also extended further to describe their synthesis strategies as well as various challenges encountered in their functionalization, dispersion, and toxicity. Our discussion also emphasizes future directions for these emerging fields of research.</P>

Carbon nanotubes: A potential material for energy conversion and storage

Kumar, Sandeep,Nehra, Monika,Kedia, Deepak,Dilbaghi, Neeraj,Tankeshwar, K,Kim, Ki-Hyun Elsevier 2018 Progress in energy and combustion science Vol.64 No.-

<P><B>Abstract</B></P> <P>Carbon nanotube-based materials are gaining considerable attention as novel materials for renewable energy conversion and storage. The novel optoelectronic properties of CNTs (e.g., exceptionally high surface area, thermal conductivity, electron mobility, and mechanical strength) can be advantageous for applications toward energy conversion and storage. Although many nanomaterials are well known for the unique structure-property relations, such relations have been sought most intensively from CNTs due to their extreme diversity and richness in structures. For the development of energy-related devices (like photovoltaic cells, supercapacitors, and lithium ion batteries), it is critical to conduct pre-evaluation of their design, operation, and performance in terms of cost, life time, performance, and environmental impact. This critical review was organized to address the recent developments in the use of CNT-based materials as working/counter electrodes and electrolytes in photovoltaic devices and as building blocks in next-generation flexible energy storage devices. The most promising research in the applications of CNTs toward energy conversion and storage is highlighted based on both computational and experimental studies along with the challenges for developing breakthrough products.</P>

Review on metallic components released due to the use of electronic cigarettes

Vinit K. Mishra,Ki-Hyun Kim,Pallabi Samaddar,Sandeep Kumar,M. L. Aggarwal,K. M. Chacko 대한환경공학회 2017 Environmental Engineering Research Vol.22 No.2

The use of electronic cigarettes (ECs) is recognized as a source of many pollutants, just like conventional cigarettes (CCs). The analysis of EC aerosol samples has confirmed the presence of various metallic species. Most of these metals originate from various parts of the cartomizer, e.g., solder joints, wires, and silicate beads. The metal concentration levels in EC samples were shown to be generally two to four orders of magnitude lower than those of CCs. However, the use of ECs can still pose significant human health hazards as consumers are exposed to the toxicity of those metals and many other hazardous pollutants released simultaneously via the vaping of ECs. The review also describes the detection and quantification of various metals in ECs and CCs. This review was carried out to assess the level of metal species released from ECs and to suggest proper guidelines to control consumer exposure.