472 results on '"Ashish Garg"'
Search Results
202. Device-Related Complications Associated with Magec Rod Usage for Distraction-Based Correction of Scoliosis
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Agarwal, Aakash, primary, Kelkar, Amey, additional, Agarwal, Ashish Garg, additional, Jayaswal, Daksh, additional, Jayaswal, Arvind, additional, and Shendge, Vithal, additional
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- 2020
- Full Text
- View/download PDF
203. Determination of defect states and surface photovoltage in PTB7:PC71BM based bulk heterojunction solar cells
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Durgesh C. Tripathi, Sandeep Pathak, Ashish Garg, and Shailendra Kumar Gupta
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Materials science ,Organic solar cell ,Renewable Energy, Sustainability and the Environment ,business.industry ,Surface photovoltage ,Photovoltaic system ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,Polymer solar cell ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Dielectric spectroscopy ,Active layer ,Photoexcitation ,Optoelectronics ,0210 nano-technology ,business - Abstract
Defects formed during the device processing acts as recombination centers and shows adverse effects on the photovoltaic performance of the organic solar cells (OSCs). In this manuscript, a study on the effect of defect states on the characteristics of bulk heterojunction (BHJ) solar cells, consisted of unannealed or thermally annealed active layer (ActL) of PTB7:PC71BM blend, have been performed by using the illumination intensity-dependent current-voltage and frequency dependent impedance spectroscopy measurements. Our results indicate that the photovoltaic performance of devices based on annealed ActL is superior than the bench dried ActL due to thermal annealing induced improvement in the thin film morphology. The measured low-frequency capacitance-voltage (C–V) characteristics under varying illumination intensities show strong dependency on the photoexcitation however, the change in the C–V characteristics is found to be quite different for unannealed and annealed devices. The C–V characteristics are analyzed using the drift-diffusion model to extract the effective built-in voltage (Vbi) and the surface photovoltage as a function of illumination intensity. The capacitance-frequency characteristics under illumination reveal that the change in the capacitance is associated with the photo-induced carrier occupation in the intermixture donor-acceptor phases, which act as the defect states in such devices. Further, it is modeled to quantify the defect states and to demonstrate the importance of thermal annealing for improving the OSCs device performance.
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- 2021
204. Effects of 10 MeV Al4+ ions irradiation on fluorine-doped tin oxide substrates for photovoltaic device applications
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L. Sowjanya Pali, Shiv P. Patel, Dhirendra K. Chaudhary, Monika Patel, Ashish Garg, Anand Pandey, and Lokendra Kumar
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Materials science ,Acoustics and Ultrasonics ,Photovoltaic system ,Inorganic chemistry ,Doping ,chemistry.chemical_element ,Condensed Matter Physics ,Tin oxide ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,chemistry ,Fluorine ,Work function ,Irradiation - Abstract
The effects of 10 MeV Al4+ ions irradiation on structural, surface morphological, optical and electrical properties of fluorine-doped tin oxide (FTO) substrates are presented for solar cell applications. The ions irradiation changes the surface morphology, average roughness, interface width, roughness exponent, and several other fractal parameters of the FTO surfaces. The UV–visible transmittance measurement shows an enhancement of transmittance in the ions irradiated substrates up to 95%. The electrical properties such as mobility, work-function, sheet resistance, and resistivity are also modified due to ions irradiation. In order to have functional applications of these ions irradiated substrates, we fabricated organic solar cells on these ions irradiated and pristine FTO substrates. The device performances are significantly improved for the case of ions irradiated FTO substrate in comparison to the pristine one. Thus, better device performance due to effective changes in physical properties suggests that the ions irradiated FTO substrates can be used as better electrodes for organic and hybrid photovoltaic device applications.
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- 2021
205. A comprehensive methodology for quantification of Bow-tie under type II fuzzy data
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Jitesh J. Thakkar, O.B. Krishna, Ashish Garg, R. K. Gangwar, Jhareswar Maiti, and Souvik Das
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Value (ethics) ,0209 industrial biotechnology ,Measure (data warehouse) ,Root (linguistics) ,Computer science ,Fuzzy set ,02 engineering and technology ,Bow tie ,Accident (fallacy) ,020901 industrial engineering & automation ,Fuzzy data ,Risk analysis (engineering) ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Software ,Event (probability theory) - Abstract
Bow-Tie is an efficient and emerging safety management tool to identify the root causes of an accident. Conventional quantification approaches for bow-tie suffer from a lack of information, insufficient data, and uncertainty. Therefore, experts’ views and knowledge about the occurrence probability of the basic events and the success probability of safety measures can be utilized to deal with the lack of information and data insufficiency issues. However, experts prefer to provide their opinion in linguistic variables that are subjected to uncertainties. To deal with these data uncertainty issues, this study has adopted the concept of type II fuzzy set for converting the subjective linguistic opinions into objective quantitative value. Bow-tie is integrated with type II fuzzy set, called F2BTA, for risk quantification. Overall, this study provides a comprehensive methodology for identifying hazardous sources & hazardous processes, developing bow-tie, quantifying top event, and providing cost-effective mitigation strategies. Besides, the Fussell–Vesely (FV) importance measure of basic events is performed to identify the strong and weak causal relations. A case study is also discussed to validate the proposed model. The results indicate that improper handling of cartridge case has the highest probability of occurrence. Accordingly, mitigation strategies are suggested to the safety management team of the case organization. The results also confirm the superiority of the proposed model. The proposed methodology also contributes significantly to safety-related decision making by the practitioners.
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- 2021
206. Herding by Foreign Institutional Investors: An Evidential Exploration for Persistence and Predictability
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Ashish Garg, Manojit Chattopadhyay, and Subrata Mitra
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050208 finance ,Commerce ,Financial economics ,0502 economics and business ,05 social sciences ,Institutional investor ,Frequency data ,Experimental and Cognitive Psychology ,Herding ,Business ,050207 economics ,Predictability ,Finance - Abstract
The primary objective of the study is to explore the predictability of herding patterns of foreign institutional investors in the Indian market using high frequency data over a period from January ...
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- 2017
207. Room temperature multiferroism in polycrystalline thin films of gallium ferrite
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Ashish Garg, Somdutta Mukherjee, Amritendu Roy, Rajeev Gupta, and Monali Mishra
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Materials science ,FOS: Physical sciences ,chemistry.chemical_element ,02 engineering and technology ,01 natural sciences ,Nuclear magnetic resonance ,0103 physical sciences ,Materials Chemistry ,Gallium ,010302 applied physics ,Condensed Matter - Materials Science ,Spin coating ,Condensed matter physics ,Mechanical Engineering ,Metals and Alloys ,Materials Science (cond-mat.mtrl-sci) ,Coercivity ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Magnetic hysteresis ,Surface coating ,chemistry ,Mechanics of Materials ,Ferrite (magnet) ,Crystallite ,0210 nano-technology - Abstract
We have synthesized (010) textured polycrystalline thin films of gallium ferrite (GaFeO 3 or GFO) on n-Si(100) and Pt/Si(111) substrates using sol-gel assisted spin coating technique. Structural characterization using x-ray diffraction and Raman spectroscopy confirms formation of single phase with crystallite size ∼37–47 nm. Magnetic characterization demonstrates saturated magnetic hysteresis loop at room temperature and indicates that due to reduced crystallite size, ferri to paramagnetic transition temperature, T C ∼300 K is higher compared to bulk GFO, reported earlier. Room temperature piezo-response force microscopic analysis reveals local ∼180° phase switching of ferroelectric domains at very high coercive field, ∼700 kV/cm, consistent with recent experimental and first-principles studies. Our study opens up the possibility of integrating polycrystalline GFO in novel room temperature multiferroic devices.
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- 2017
208. Solution-Processed Organic Solar Cells Using New Electron Acceptor Derived from Naphthalene and Fluorene Unit
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P. Nagarjuna, Anirban Bagui, Surya Prakash Singh, Neha Chaturvedi, Ashish Garg, and Rashmi Runjhun
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chemistry.chemical_classification ,Organic solar cell ,Chemistry ,02 engineering and technology ,General Chemistry ,Electron acceptor ,Fluorene ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Polymer solar cell ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,law ,Solar cell ,Phenyl group ,0210 nano-technology ,HOMO/LUMO ,Derivative (chemistry) - Abstract
We have developed two new electron acceptors NAP-C60 and N4 derived from naphthalene and fluorene, respectively for solution processed organic solar cells. In the case of NAP-C60, [6, 6]-phenyl C61-butyric acid methyl ester (PC61BM) basic structure is modified by replacing its phenyl group with naphthalene group; while in the case of N4, diaryl fullerene structure was modified using fluorene group. The UV-visible spectra of the molecules show strong absorption in the UV region. Cyclic-voltammetry measurements yielded the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of N4 and NAP-C60 molecules as (-5.63 eV, −3.69 eV) and (5.80 eV, −3.70 eV), respectively. The best solar cell devices made from PTB7:NAP-C60 and PTB7:N4 bulk composite films resulted in power conversion efficiencies of 4.1 and 4.3 %, respectively. The diarylmethanofullerene derivative N4 shows a higher open circuit voltage compared to the methanofullerene derivative NAP-C60, attributed to low lying LUMO levels of N4.
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- 2017
209. Effect of annealing atmosphere on leakage and dielectric characteristics of multiferroic gallium ferrite
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Ashish Garg, A.S. Daryapurkar, Rajeev Gupta, Shailendra Rajput, Vijay A. Singh, and Somdutta Mukherjee
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010302 applied physics ,Materials science ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Activation energy ,Dielectric ,021001 nanoscience & nanotechnology ,01 natural sciences ,Oxygen ,chemistry ,X-ray photoelectron spectroscopy ,Vacancy defect ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,Grain boundary ,Crystallite ,Gallium ,0210 nano-technology - Abstract
Mutliferroic and magnetoelectric gallium ferrite (GaFeO3) is plagued by substantial electrical leakage in polycrystalline form. Here, we report on understanding the conduction mechanism in gallium ferrite ceramic samples vis-a-vis processing conditions. The results show that oxygen annealed samples exhibit minimum electrical leakage as compared to air or nitrogen annealed samples suggesting the role of oxygen vacancies on electrical conduction. Detailed time and temperature dependent impedance spectroscopy analysis of the samples showed higher activation energy of conduction in oxygen annealed samples than in air or nitrogen annealed samples. The lower activation energies of 0.3-0.4 eV in nitrogen/air annealed samples were attributed to higher oxygen vacancy concentration while oxygen annealed samples with low oxygen vacancy concentration exhibited higher activation energy of ~0.50 eV (high frequency i.e. grain) and 0.98 eV (low frequency i.e. grain boundary), latter due to superior level of oxygenation at the grain boundaries. Further, X-ray photoelectron spectroscopy revealed that the oxygen vacancies are compensated by the valence fluctuation between Fe2+/Fe3+ ions whose extent is higher in air/nitrogen annealed samples than in oxygen annealed samples. The conduction mechanisms that could be active are most likely to be double ionization of oxygen vacancies and hopping between Fe2+ to Fe3+ states, latter especially in oxygen deficient samples. This article is protected by copyright. All rights reserved.
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- 2017
210. SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF SOME NOVEL 2, 3-DISUBSTITUED QUINAZOLIN-4-(3H)-ONES
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Sweta Garg and Ashish Garg
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0106 biological sciences ,Semicarbazide ,Hydrochloride ,Chemical modification ,Oxadiazole ,Biological activity ,Quinazoline ,Quinazolin4(3H)One ,Antimicrobial ,Anti-Inflammatory ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,chemistry.chemical_compound ,chemistry ,Semicarbazone ,Quinazolinone ,010606 plant biology & botany - Abstract
A new series of 2, 3-disubstituted quinazolin4(3H)one derivatives was synthesized in good yield with the use of different aldehydes and evaluate their antimicrobial and anti-inflammatory activities. Disubstituted quinazolin4(3H)one derivatives were synthesized from Semicarbazide Hydrochloride and semicarbazone as starting materials through oxadiazole as intermediates. This intermediate on reaction with benoxazinone in acidic media, finally converted into corresponding 2, 3-disubstituted quinazolinone derivatives. The synthesized compounds were characterized by their physical properties, Infra-red (IR), nuclear magnetic resonance (NMR), Mass spectroscopic (MS) and elemental analysis and evaluated for biological activities. Ten different analogues of 2, 3-disubstituted quinazolin4(3H)one were successfully synthesized. All the compounds were active against microbial growth and inflammation. They all give good to moderate result on comparison with standard drug. The results reveal that pharmacological activity of quinazolin4(3H)one nucleus can be increased much times on chemical modification. This is advantageous to approaching the treatment of different kinds of severe diseases.
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- 2017
211. An efficient route to fabricate fatigue-free P(VDF-TrFE) capacitors with enhanced piezoelectric and ferroelectric properties and excellent thermal stability for sensing and memory applications
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Deepa Singh, Ashish Garg, and Deepak
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Fabrication ,Piezoelectric coefficient ,Materials science ,business.industry ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,Piezoelectricity ,0104 chemical sciences ,law.invention ,Capacitor ,law ,Optoelectronics ,Thermal stability ,Physical and Theoretical Chemistry ,Thin film ,0210 nano-technology ,business ,Low voltage - Abstract
P(VDF-TrFE), the best known ferroelectric polymer, suffers from a rather low piezoelectric response as well as poor electrical fatigue life, hampering its application potential. Herein, we report the fabrication of fatigue free poly(vinylidenedifluoride-trifluoroethylene) P(VDF-TrFE)-based capacitors with record piezoelectric coefficients and excellent thermal stability. We proposed a cost-effective and simple solution-based process to fabricate P(VDF-TrFE)-based memory capacitors with large polarization (8.9 μC cm-2), low voltage operation (15 V), and excellent fatigue endurance with 100% polarization retention up to 108 electrical switching cycles. The thin film capacitors fabricated using methyl ethyl ketone (MEK) and dimethyl sulfoxide (DMSO) as co-solvents also show a much higher piezoelectric coefficient (d33 = -60 pm V-1) than the previously reported capacitors and are also thermally stable up to 380 K, making them ideal candidates for ferro-, piezo-, and pyro-electric applications, even in devices operating above room temperature. The observed results are well supported by first principles calculations, FTIR, XPS, and evaluation of cohesion energy for crystallization by DSC.
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- 2017
212. Effect of Microstructural Anisotropy on the Electrochemical Behavior of Rolled Mild Steel
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V. Nanda, Shashank Shekhar, S. Choudhary, K. Mondal, and Ashish Garg
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010302 applied physics ,Diffraction ,Materials science ,Mechanical Engineering ,Metallurgy ,02 engineering and technology ,Electron ,021001 nanoscience & nanotechnology ,01 natural sciences ,Grain size ,Corrosion ,Mechanics of Materials ,0103 physical sciences ,General Materials Science ,Grain boundary ,Deformation (engineering) ,Composite material ,0210 nano-technology ,Anisotropy ,Electron backscatter diffraction - Abstract
Warm rolling of a mild steel at 600 °C generates a microstructural anisotropy in the different planes corresponding to rolling direction, normal direction and transverse direction manifested by differences in the grain structure and the type of grain boundaries. The work concentrates on studying the effect of this microstructural anisotropy on the electrochemical behavior of the steel plates using microscopic examination and electron backscattered diffraction. The results show that the corrosion behavior of the samples depends mainly on the fraction of high-angle grain boundaries or corresponding average grain size, which, in turn, depends on the degree of deformation on different planes determined by the extent of thickness reduction. On the other hand, low-angle grain boundaries have little effect on the corrosion of all the three different planes.
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- 2016
213. Purse String Suture Closure: A Useful Double-Layer Technique for Closure of an Oronasal Communication
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Neha Jajodia, Ashish Garg, Santosh Kumar Agarwal, and Virendra Singh
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Purse string suture ,medicine.medical_specialty ,Polyglactin suture ,business.industry ,Closure (topology) ,030206 dentistry ,Greater palatine artery ,Surgery ,03 medical and health sciences ,Plastic surgery ,0302 clinical medicine ,medicine.anatomical_structure ,Otorhinolaryngology ,Treatment modality ,Technical Note ,medicine ,Oral Surgery ,030223 otorhinolaryngology ,business - Abstract
Introduction Various treatment modalities are reported in the literature for the management of oronasal communication. Single-layer closure often leads to failure and persists a major concern to an operative surgeon. Therefore, double-layer closure is one of the keys to successful management of oronasal communication. Meterial and method A continuous intramucosal running purse string suture at submucosal depth was placed circumferentially around the defect margin with 3-0 round body polyglactin suture as a first layer. Pedicled palatal rotation axial flap based on greater palatine artery was used as the second layer of closure, above the first palatal submucosal layer. Conclusion Intramucosal purse string suture technique provides adjacent local tissue for closure of oronasal communication. This technique is easy and can be used as an alternative option for double-layered closure of an oronasal communication, without donor site morbidity and minimal patient discomfort.
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- 2018
214. Fluid Dynamics Android Application: An Efficient Semi-Implicit Solver for Compressible Flows
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Shivam Singhal, Ashish Garg, and Yayati Gupta
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Computer science ,computational_mathematics ,Fluid dynamics ,Compressibility ,Android application ,Solver ,Computational science - Abstract
The computing power of smartphones has not received considerable attention in the mainstream education system. Most of the education-oriented smartphone applications (apps) are limited to general purpose services like Massive Open Online Courses (MOOCs), language learning, and calculators (performing basic mathematical calculations). Greater potential of smartphones lies in educators and researchers developing their customized apps for learners in highly specific domains. In line with this, we present Fluid Dynamics, a highly accurate Android application for measuring flow properties in compressible flows. This app can determine properties across the stationary normal and oblique shock, moving normal shock and across Prandtl $-$ Meyer expansion fan. This app can also measure isentropic flows, Fanno flows, and Rayleigh flows. The functionality of this app is also extended to calculate properties in the atmosphere by assuming the International Standard Atmosphere (ISA) relations and also flows across the Pitot tube. Such measurements are complicated and time-consuming since the relations are implicit and hence require the use of numerical methods, which give rise to repetitive calculations. The app is an efficient semi-implicit solver for gas dynamics formulations and uses underlying numerical methods for the computations in a graphical user interface (GUI), thereby easing and quickening the learning of concerned users. The app is designed for the Android operating system, the most ubiquitous and capable surveillance platform, and its calculations are based on JAVA based code methodology. In order to check its accuracy, the app's results are validated against the existing data given in the literature.
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- 2019
215. Milli-Watt Power Harvesting from Dual Triboelectric and Piezoelectric Effects of Multifunctional Green and Robust Reduced Graphene Oxide/P(VDF-TrFE) Composite Flexible Films
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Prateek, Ritamay Bhunia, Raju Kumar Gupta, Bushara Fatma, Ashish Garg, and Shashikant Gupta
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010302 applied physics ,Materials science ,Nanocomposite ,business.industry ,Graphene ,Composite number ,Nanogenerator ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Piezoelectricity ,law.invention ,law ,0103 physical sciences ,Finger tapping ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Energy harvesting ,Triboelectric effect - Abstract
For a variety of mechanical energy harvesting as well as biomedical device applications, flexible energy devices are useful which require the development of environment-friendly and robust materials and devices. In this manuscript, we demonstrate a lead-free, facile, low-cost, sol-gel-processed reduced graphene oxide (rGO)/P(VDF-TrFE) nanocomposite with multipurpose capability demonstration as a piezoelectric nanogenerator (PENG) and hybrid piezoelectric triboelectric nanogenerator (HPTENG) devices. The structural analysis of the materials shows that the interactions between the rGO and P(VDF-TrFE) matrix help in breaking the centrosymmetry of rGO, resulting in a strong enhancement in the piezoelectric, ferroelectric, and triboelectric properties of composites over pristine P(VDF-TrFE) films. In the case of PENG, the composite devices showed >22 times improvement in the piezoelectric output voltage over the pristine P(VDF-TrFE) PENG device with the highest output voltage of 89.7 V for the 0.5 wt % rGO composite. Also, HPTENG devices based on composite films generated an average VOC of 227 V, much higher than the pristine P(VDF-TrFE)-based devices. Maximum output power densities measured were 0.28 W/cm3 and 0.34 mW/cm3 for hybrid piezoelectric-triboelectric and piezoelectric devices, respectively. The triboelectric devices demonstrated lighting of 45 blue light-emitting diodes directly, connected in series, by harvesting mechanical energy generated by repeated finger tapping. The study highlights the promise of rGO/P(VDF-TrFE) composites for PENG and HPTENG devices with dramatically improved electrical output.
- Published
- 2019
216. The effect of tooth morphology and vertical bracket positioning on resultant stress in periodontal ligament- a three dimensional finite element study
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Upendra Singh Bhadauria, Bhavna Virang, Ashish Garg, and Rohit Kumar Maheshwari
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Orthodontics ,FEM ,Materials science ,Bracket ,General Medicine ,Finite element method ,Stress (mechanics) ,stomatognathic diseases ,stomatognathic system ,Vertical direction ,PDL stress ,Periodontal fiber ,Cusp (anatomy) ,Crest ,Maxillary central incisor ,vertical bracket position ,Original Research ,Dental Medicine - Abstract
Introduction. The purpose of this study is to evaluate the effect of change in vertical placement of bracket and effect of tooth morphology on stress developed on periodontal ligament with the help of three dimensional finite element modeling. Methods. A three-dimensional model of the maxillary bone, maxillary right central incisor, lateral incisor and canine was designed based on the average dimensions of the anatomy and morphology given by Wheeler’s and standard edgewise bracket with Slot of 0.022″ X 0.028″ inch was designed using the finite element method. Brackets were placed on each tooth, on the mentioned labial surface at variable distances from the cusp tip, and a full size archwire was virtually engaged into the bracket, then optimum orthodontic load of 2N is applied and PDL stress were calculated. Results. The lowest stress values were measured as bracket position changes from crest of teeth to the apical direction. By displacing the bracket gingivally from 1.5 to 6 mm, a 16.2% decrease in stress level for central incisor, for lateral incisor the stress level decrease by 25.8% and for canine the stress level decrease by 21.6% thus our study confirms that variation in vertical bracket position results in change in resultant stress in PDL. Conclusion.It can be concluded that the variation in the vertical position of the bracket on different tooth can have an important effect on the stresses developed in the PDL.
- Published
- 2019
217. Significantly Enhanced Energy Density by Tailoring the Interface in Hierarchically Structured TiO
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Prateek, Ritamay, Bhunia, Shahil, Siddiqui, Ashish, Garg, and Raju Kumar, Gupta
- Abstract
Dielectric polymer nanocomposites with a high breakdown field and high dielectric constant have drawn significant attention in modern electrical and electronic industries due to their potential applications in dielectric and energy storage systems. The interfaces of the nanomaterials play a significant role in improving the dielectric performance of polymer nanocomposites. In this work, polydopamine (dopa)-functionalized TiO
- Published
- 2019
218. Momentum Turning Points
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Michele Mazzoleni, Campbell R. Harvey, Ashish Garg, and Christian L. Goulding
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History ,Mathematical optimization ,Polymers and Plastics ,Computer science ,Selection strategy ,Equity (finance) ,Market timing ,Behavioral economics ,Industrial and Manufacturing Engineering ,Trend following ,Mean reversion ,Capital asset pricing model ,Business and International Management ,Volatility (finance) - Abstract
Turning points are the Achilles' heel of time-series momentum portfolios. Slow signals fail to react quickly to changes in trend while fast signals are often false alarms. We examine theoretically and empirically how momentum portfolios of various intermediate speeds, formed by blending slow and fast strategies, cope with turning points. Our model predicts a mean-variance optimal dynamic speed selection strategy. We apply this strategy across domestic and international equity markets and document efficient out-of-sample performance. We also propose a novel decomposition of momentum strategy alpha, highlighting the role of volatility timing.
- Published
- 2019
219. Active Learning for Domain Classification in a Commercial Spoken Personal Assistant
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Christopher Klein, Ashish Garg, Stephen Pulman, Jason D. Williams, Justine T. Kao, Tony Y. Li, Adithya Sagar, and Xi C. Chen
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FOS: Computer and information sciences ,Computer Science - Machine Learning ,Training set ,SIMPLE (military communications protocol) ,business.industry ,Active learning (machine learning) ,Computer science ,Machine Learning (stat.ML) ,Machine learning ,computer.software_genre ,Domain (software engineering) ,Machine Learning (cs.LG) ,Annotation ,Statistics - Machine Learning ,If and only if ,Component (UML) ,Selection (linguistics) ,Artificial intelligence ,business ,computer - Abstract
We describe a method for selecting relevant new training data for the LSTM-based domain selection component of our personal assistant system. Adding more annotated training data for any ML system typically improves accuracy, but only if it provides examples not already adequately covered in the existing data. However, obtaining, selecting, and labeling relevant data is expensive. This work presents a simple technique that automatically identifies new helpful examples suitable for human annotation. Our experimental results show that the proposed method, compared with random-selection and entropy-based methods, leads to higher accuracy improvements given a fixed annotation budget. Although developed and tested in the setting of a commercial intelligent assistant, the technique is of wider applicability.
- Published
- 2019
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- View/download PDF
220. Insulin
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John M. Beals, Michael R. DeFelippis, Chad D. Paavola, David P. Allen, Ashish Garg, and D. Bruce Baldwin
- Published
- 2019
221. Unveiling the Role of Graphene Oxide as an Interface Interlocking Ingredient in Polyvinylidene Fluoride‐Based Multilayered Thin‐Film Capacitors for High Energy Density and Ultrafast Discharge Applications
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Ashish Garg, Prateek, Arnab Sarkar, Sandeep Anand, Ritamay Bhunia, and Raju Kumar Gupta
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Materials science ,business.industry ,Graphene ,Oxide ,Polyvinylidene fluoride ,Energy storage ,law.invention ,chemistry.chemical_compound ,Capacitor ,General Energy ,chemistry ,law ,Barium titanate ,Optoelectronics ,Thin film ,business ,Ultrashort pulse - Published
- 2021
222. Grain size dependence of electrical transport in magnetoelectric gallium ferrite ceramics
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Ujjval Bansal, Rajeev Gupta, Kumar Brajesh, Vijay A. Singh, and Ashish Garg
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Materials science ,Mechanical Engineering ,Metals and Alloys ,Sintering ,chemistry.chemical_element ,02 engineering and technology ,Activation energy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Grain size ,0104 chemical sciences ,chemistry ,Mechanics of Materials ,Electrical resistivity and conductivity ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Grain boundary ,Crystallite ,Ceramic ,Composite material ,Gallium ,0210 nano-technology - Abstract
Engineering microstructural features such as grain size in ceramic materials have strong effect on the various properties of materials. In this manuscript, we demonstrate the effect of grain size on electrical transport in polycrystalline gallium ferrite (GaFeO3 or GFO) samples prepared by solid-state-reaction method. We varied the grain size of the polycrystalline GFO samples by changing the duration of sintering, increasing from 9 μm to 21 μm with the increase in sintering time from 12 h to 256 h at 1350 °C. The samples remain phase-pure without any secondary phase formation upon changing sintering duration. Leakage current density of the samples reduces by nearly four orders of magnitude as the grain size increases from 9 μm to 21 μm. Time and temperature dependent impedance measurements revealed that while the grain boundaries in GFO samples were more insulating than the grains with higher activation energy of 0.65–0.95 eV in comparison to 0.30–0.47 eV for the grains, grain resistivity increases with increase in the sintering duration. Latter is attributed to increasing grain conduction activation energy, caused by migration of oxygen vacancies toward grain boundaries as the sintering time increases resulting in a concomitant decrease in grain boundary conduction activation energy. The study suggests towards a subtle balance between grain and grain boundary conductivities which eventually drive the overall electrical leakage of GFO ceramics. The study also highlights the role of microstructural engineering in tailoring the electrical properties of magnetoelectric GFO ceramics without resorting to atomic substitution.
- Published
- 2020
223. Buffer layers in inverted organic solar cells and their impact on the interface and device characteristics: An experimental and modeling analysis
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Suman Banerjee, Shailendra Kumar Gupta, Ashish Garg, and Arjun Singh
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Materials science ,Organic solar cell ,Analytical chemistry ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,Biomaterials ,chemistry.chemical_compound ,law ,Materials Chemistry ,Electrical and Electronic Engineering ,Open-circuit voltage ,business.industry ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Phenyl-C61-butyric acid methyl ester ,Cathode ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Anode ,Dielectric spectroscopy ,chemistry ,Optoelectronics ,Charge carrier ,0210 nano-technology ,business ,Current density - Abstract
Buffer layers play crucial role in increasing the power conversion efficiencies (η) in organic solar cells (OSCs) and hence it is important to understand the underlying microscopic mechanisms behind the improvements aiding the existing qualitative understanding. In this manuscript, we have investigated the role of zinc oxide (ZnO) and molybdenum oxide (MoO3) buffer layers on the current density - voltage (J-V) characteristics of inverted organic solar cell (IOSC) devices combining experimental results with drift-diffusion based transport modeling, on the active layer (ActL) blend of P3HT:PCBM (Poly 3-hexylthiophene (P3HT): (6, 6) phenyl C61 butyric acid methyl ester (PC61BM)), a workhorse system with well-established device data. The results show that while ZnO alone improves the open circuit voltage (VOC) significantly, use of both the ZnO and MoO3 layers help in improving the short-circuit current density (JSC), aided by contributions to exciton dissociation by both layers at the electrode ActL interface. Absence of ZnO, in particular, causes S-shaped J-V curve which is attributed to reduced surface recombination velocity of majority carriers due to hindered charge extraction and non-selectivity of carrier flow towards cathode. On the other hand, presence of MoO3film between ActL and the anode assists in making an energetically favourable contact with ActL and improves the extraction of photo generated charge carriers. Further in conjunction with dark J-V characteristics, impedance spectroscopy (IS) carried out under dark and illuminated conditions establishes the role of buffer layers in modifying the barrier heights at the contacts and the interfacial structure.
- Published
- 2016
224. Inverted polymer bulk heterojunction solar cells with ink-jet printed electron transport and active layers
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Shailendra Kumar Gupta, Arjun Singh, and Ashish Garg
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Materials science ,Organic solar cell ,business.industry ,Annealing (metallurgy) ,Drop (liquid) ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Polymer solar cell ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Active layer ,Indium tin oxide ,Biomaterials ,Materials Chemistry ,Transmittance ,Optoelectronics ,Electrical and Electronic Engineering ,Thin film ,0210 nano-technology ,business - Abstract
Ink-jet printing is a potentially attractive technique for printing of components for organic electronic devices primarily due to its ability to print patterned layers and reduced ink wastage. However, the mechanism of film formation is quite complex and needs an understanding of various printing parameters on the film growth. In this manuscript, we successfully demonstrate ink-jet printing of smooth zinc oxide (ZnO) thin films with controlled thickness as electron transport layers for inverted organic solar cell devices fabricated on indium tin oxide coated glass substrates. The parameters that strongly affect the formation of a continuous ZnO thin film with controlled thickness are ink concentration and viscosity, substrate surface treatment, drop spacing, substrate temperature during printing and the annealing temperature, affected by a combination of surface energetics, surface tension of the ink and the rate of solvent evaporation. The results suggest that one can achieve a transmittance of >85% for a 45 nm thin ZnO film possessing uniform structure and morphology, fabricated using a drop spacing of 40–50 μm at an ink viscosity of 4.70 cP with substrate held at room temperature. The P3HT:PC 61 BM inverted organic solar cell devices fabricated using printed ZnO films as electron transporting layers exhibit an efficiency of ∼3.4–3.5%, comparable to that shown by the devices fabricated on spin coated ZnO films. Finally, the device with printed P3HT:PC 61 BM active layer on printed ZnO layer showed a device efficiency of ca . 3.2% suggesting that nearly completely printed devices can deliver a comparable performance to the spin coated devices.
- Published
- 2016
225. Inverted P3HT:PCBM organic solar cells on low carbon steel substrates
- Author
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L. Sowjanya Pali, Palaniswamy Ganesan, and Ashish Garg
- Subjects
Photoluminescence ,Materials science ,Fabrication ,Organic solar cell ,Opacity ,Renewable Energy, Sustainability and the Environment ,business.industry ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Active layer ,law.invention ,law ,Electrode ,Solar cell ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Lithography - Abstract
Solar cell device fabrication on opaque metallic substrates is limited by the transmission of light from top transparent electrode. Moreover, conductivity of the substrates requires insulation for cell integration in a module. In this manuscript, we report fabrication of inverted ITO-free organic solar cells on opaque steel substrates without use of any lithography with power conversion efficiencies of ca. 1.35%. The device structure was Steel/Insulator/Al/ZnO/P3HT:PC60BM/MoO3/Au. The insulated substrates were first planarized using a thin poly(methymethacrylate) or PMMA layer to minimize the substrate roughness and to enable the fabrication of subsequent layers with minimum roughness. We investigated the effect of thickness of various layers to maximize the performance of these devices with major emphasis on improving the transmission of top electrode to maximize the light absorption in the active layer blend. For best photovoltaic characteristics of the devices, thickness determination of thin transparent conducting layer of gold was carried out by conducting transmission, conductivity and morphological studies. Solution processed ZnO on Aluminum showed ridge like structure which provides larger interfacial area for the collection of electrons. Photoluminescence measurements on Active layer/MoO3 emphasize the importance of insertion of sufficiently thin MoO3 layer in the device in terms of efficient exciton dissociation.
- Published
- 2016
226. Heparin-appended polycaprolactone core/corona nanoparticles for site specific delivery of 5-fluorouracil
- Author
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Ashish Garg, Rajeev Sharma, Awesh K. Yadav, Vaibhav Patel, and A. Jain
- Subjects
Materials science ,Polyesters ,Biomedical Engineering ,Cmax ,Pharmaceutical Science ,Medicine (miscellaneous) ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,Drug Delivery Systems ,Pharmacokinetics ,Zeta potential ,Humans ,Cytotoxicity ,Heparin ,General Medicine ,021001 nanoscience & nanotechnology ,In vitro ,0104 chemical sciences ,chemistry ,A549 Cells ,Polycaprolactone ,Nanoparticles ,Fluorouracil ,Particle size ,0210 nano-technology ,Biotechnology ,Nuclear chemistry - Abstract
The aim of the present work is to formulate heparin-modified-polycaprolactone (HEP) core shell nanoparticles (NPs) of 5-fluorouracil (5-FU). These NPs were characterized for various in vitro parameters like particle size, zeta potential, etc. HEP NPs were found to maintain comparatively slower drug release pattern (98.9% in 96 h) than PCL NPs. Cytotoxicity studies demonstrated a massive cytotoxic potential of 5-FU-loaded HEP NPs in A549, MDA-MD-435, and SK-OV-3 cancer cell lines. Pharmacokinetic parameters were also determined in blood after IV administration of HEP NPs: AUC, Cmax, MRT, and Tmax values are 6096.075 ± 5.90 μg h/mL, 144.38 ± 1.52 μg/L, 58.71 ± 0.25 h, 96 ± 0.50 h, respectively and 117.92 ± 1.78, 45.35 ± 3.00, 1.2 ± 0.25, 0.5 ± 0.02 in plain 5-FU solution.
- Published
- 2016
227. Relation Between Open Circuit Potential and Polarization Resistance with Rust and Corrosion Monitoring of Mild Steel
- Author
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S. Choudhary, K. Mondal, and Ashish Garg
- Subjects
Materials science ,Open-circuit voltage ,Linear polarization ,020209 energy ,Mechanical Engineering ,Metallurgy ,Corrosion monitoring ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Corrosion ,Mechanics of Materials ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,0210 nano-technology ,Polarization (electrochemistry) - Abstract
The present work discusses continuous corrosion assessment from a unique correlation of open circuit potential (OCP) and linear polarization resistance with rust formation on mild steel after prolong exposure in 3.5% NaCl salt fog environment. The OCP measurement and linear polarization tests were carried out of the rusted samples only without the removal of rust. It also discusses the strong influence of the composition, fraction, and morphology of the rust layers with OCP and linear polarization resistance. The rust characterization was done after the measurement of OCP and linear polarization resistance of the rusted steel samples. Therefore, monitoring of both the OCP and linear polarization resistance of the rusted mild steels coupled with rust characterization could be used for easy and dynamic assessment of the nature of corrosion.
- Published
- 2016
228. Pediatric Resident Attitudes and Knowledge of Critical Congenital Heart Disease Screening
- Author
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Ivan L. Hand, Anshul Arora, and Ashish Garg
- Subjects
Health Knowledge, Attitudes, Practice ,medicine.medical_specialty ,Heart Diseases ,New York ,Academic institution ,03 medical and health sciences ,0302 clinical medicine ,Surveys and Questionnaires ,030225 pediatrics ,Intervention (counseling) ,medicine ,Humans ,030212 general & internal medicine ,Critical congenital heart disease ,Child ,Pediatric resident ,business.industry ,Significant difference ,Internship and Residency ,Vascular surgery ,Confidence interval ,Family medicine ,Pediatrics, Perinatology and Child Health ,Health law ,Cardiology and Cardiovascular Medicine ,business - Abstract
This study aimed to understand the knowledge, attitudes and confidence level related to critical congenital heart disease (CCHD) screening among pediatric residents. Pediatric residents were assessed via an anonymous survey related to CCHD guidelines and procedures as set out by the New York State Department of Health. The survey was emailed to pediatric residents at a large academic institution. A teaching intervention was performed after the initial survey, which was followed by an identical after-intervention survey. Forty-two residents responded to the pre-intervention survey (n = 42), and forty post-intervention (n = 40). The mean composite knowledge score was 76 % pre-intervention and 92 % post-intervention, p
- Published
- 2016
229. An Investigative and Explanatory Review on Use of Milk as a Broad-Spectrum Drug Carrier for Improvement of Bioavailability and Patient Compliance
- Author
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Rajesh Kumar, Sukhwinder Singh, Daljit Kaur, Manoj Kumar Katual, Ashish Garg, Amit Sharma, and Sukhmeet Singh Kamal
- Subjects
business.industry ,food and beverages ,02 engineering and technology ,021001 nanoscience & nanotechnology ,030226 pharmacology & pharmacy ,Biotechnology ,Bioavailability ,03 medical and health sciences ,Broad spectrum ,Regimen ,fluids and secretions ,0302 clinical medicine ,Casein ,Research studies ,Medicine ,General Pharmacology, Toxicology and Pharmaceutics ,0210 nano-technology ,business ,Patient compliance ,Drug carrier - Abstract
Objective: The main objective of this review is to investigate the potential role of milk in improvement of bioavailability and patient compliance. Method: The study reviews the types of milk based on its composition, mechanism of how milk improves the solubility of poorly soluble drugs, masks the taste of bitter drugs and improves the patient compliance to dosage regimen. It also reviews various research studies done so far that recommend the use of milk in formulations. Along with this, the regulatory aspect of using milk is also considered in the present study. Conclusion: Investigation concludes that medicated milk formulations open a new hope of utilizing milk as multi-functional drug carrier for a variety of drugs. Key words: Milk, Solubility, Bitter, Casein, Fat, Pediatric.
- Published
- 2016
230. Do foreign institutional investors herd in emerging markets? A study of individual stocks
- Author
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Ashish Garg, Dilip Kumar, and Subrata Mitra
- Subjects
040101 forestry ,050208 finance ,Financial economics ,05 social sciences ,Institutional investor ,04 agricultural and veterinary sciences ,0502 economics and business ,Herd ,0401 agriculture, forestry, and fisheries ,Stock market ,Business ,Herding ,Emerging markets ,Herd behavior ,Stock (geology) ,Panel data - Abstract
This paper attempts to examine the presence of herd behavior among the foreign institutional investors (FIIs) when investing in Indian stock market. We also examine the impact of herding in FIIs on stock returns using panel regression approach. We apply the measure suggested by Lakonishok et al. (J Financ Econ 32(1):23–43, 1992), hereafter referred as LSV, to detect the buy-side and the sell-side herding in the Indian stock market. In order to find out intertemporal trading pattern of FIIs, we also use SIAS model. This paper makes use of daily data of 50 stocks of S&P CNX Nifty to achieve the goals. The study also tries to develop a volume-based herding ratio to extend the findings. The results support the evidence of presence of both buy-side and sell-side herding in the Indian stock market. The results based on panel regression approach highlights the destabilizing effect of FIIs in the Indian stock market that may be an issue of concern for the regulators.
- Published
- 2016
231. The combined effect of mechanical strain and electric field cycling on the ferroelectric performance of P(VDF-TrFE) thin films on flexible substrates and underlying mechanisms
- Author
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Deepa Singh, Deepak, and Ashish Garg
- Subjects
010302 applied physics ,Materials science ,Delamination ,General Physics and Astronomy ,02 engineering and technology ,Bending ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,law.invention ,Capacitor ,law ,Electric field ,0103 physical sciences ,Electrode ,Physical and Theoretical Chemistry ,Composite material ,Thin film ,0210 nano-technology ,Polarization (electrochemistry) - Abstract
In this manuscript, we study the combined effect of mechanical strain and electric field cycling on the ferroelectric properties and polarization fatigue of P(VDF-TrFE) based flexible thin film capacitors from the perspective of flexible memory applications. The devices show nearly 80% retention of ferroelectric polarization after 30 000 bending cycles at mechanical strains of up to ca. 0.8%, mimicking a typical number of bending cycles a product is expected to go through. On the other hand, electric field cycling of the unstrained as well as mechanically strained devices results in over 50% drop in the ferroelectric polarization of the capacitors within 105 bipolar switching cycles. We find that 20% reduction in the polarization upon mechanical cycling is due to the formation of cracks in P(VDF-TrFE) thin films whilst ca. 50% polarization reduction during purely electrical or mechano-electrical fatigue is concomitant with the development of bubbles in the top electrode of the devices which eventually coalesce to give rise to bursting and eventual delamination of the electrode. A detailed investigation into the electrical fatigue mechanisms shows that the fatigue is primarily driven by the degradation of the P(VDF-TrFE) thin films due to HF elimination triggered by a high enough electric field, also manifested by reduced crystallinity and a reduced number of total dipoles of P(VDF-TrFE) films. The results clearly suggest that polarization reduction upon electric field cycling i.e. electrical fatigue is a greater bottleneck in the use of flexible memory devices than the mechanical cycling.
- Published
- 2016
232. Exploration of eosinopenia as a diagnostic parameter to differentiate sepsis from systemic inflammatory response syndrome: Results from an observational study
- Author
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Seema Bhargava, Rahul Singh, Sumit Ray, Imran Gafoor, L. M. Srivastava, Debashish Dhar, Dimple Anand, and Ashish Garg
- Subjects
medicine.medical_specialty ,Critical Care and Intensive Care Medicine ,Brief Communication ,Gastroenterology ,Procalcitonin ,Sepsis ,sepsis ,03 medical and health sciences ,0302 clinical medicine ,Absolute eosinophil count ,Internal medicine ,medicine ,Eosinopenia ,Diagnostic biomarker ,030212 general & internal medicine ,negative predictive value ,business.industry ,030208 emergency & critical care medicine ,Eosinophil ,respiratory system ,medicine.disease ,Predictive value ,Systemic inflammatory response syndrome ,systemic inflammatory response syndrome ,medicine.anatomical_structure ,Immunology ,Observational study ,business ,hormones, hormone substitutes, and hormone antagonists ,procalcitonin - Abstract
Aim of the Study: Initial differentiation of sepsis from systemic inflammatory response syndrome (SIRS) is of prime importance for early institution of appropriate treatment. This study aimed to compare the differential diagnostic efficacy of absolute eosinophil count (AEC - a routinely available economic marker) with total leukocyte count (TLC) and procalcitonin (PCT - a costly marker available only in specialized settings). Materials and Methods: In this prospective observational study, 170 patients of sepsis (severe sepsis = 125; SIRS = 45) were enrolled. AEC, TLC, and PCT were measured in the blood of all patients at the time of admission and data analyzed statistically. Results: Median AEC was 0 cells/mm3 in both SIRS and sepsis. TLC and PCT levels were significantly higher (P < 0.001) in culture negative, culture positive, and overall sepsis groups in comparison to SIRS group. At a cutoff of < 50 cells/mm3, AEC demonstrated a sensitivity and specificity of 23% and 68%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of TLC were 57%, 71%, 85%, 37% and of PCT were 82.4%, 82.2%, 93%, and 63%, respectively with area under curve of 0.455 for AEC, 0.640 for TLC, 0.908 for PCT. Conclusions: This study suggests that eosinopenia is not a reliable diagnostic tool to differentiate sepsis from SIRS. PCT and TLC are better differential diagnostic biomarkers.
- Published
- 2016
233. Enhancement in magnetic properties of Ba-doped BiFeO 3 ceramics by mechanical activation
- Author
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Ashish Garg, Samar Layek, and Harish Verma
- Subjects
Materials science ,Mechanical Engineering ,Doping ,Metals and Alloys ,Analytical chemistry ,Coercivity ,Magnetization ,chemistry.chemical_compound ,Nuclear magnetic resonance ,chemistry ,Mechanics of Materials ,Mössbauer spectroscopy ,Materials Chemistry ,Multiferroics ,Crystallite ,Perovskite (structure) ,Bismuth ferrite - Abstract
Here, we report on the enhancement in the magnetic properties of polycrystalline Bi1−xBaxFeO3 (x = 0.0, 0.05, 0.1 and 0.2) ceramic samples as a consequence of mechanical activated solid-state-reaction in comparison to standard solid-state-reaction processed samples. Our results suggest that mechanical activation has pronounced effect on the temperature of phase evolution as well as magnetic characteristics of Ba doped BiFeO3. The temperature, at which perovskite phase crystallizes is lower for mechanical activation assisted samples than for standard solid-state-reaction processed samples, attributed to pre-alloying during mechanical activation process. All the samples crystallize in a distorted perovskite structure with space group R3c and no structural change is found up to highest Ba doping. Mechanical activation also leads to significantly altered magnetic properties, particularly in higher Ba-doping samples which show about 50% increase in the magnetization and more than three fold increase in the coercive field. Local magnetic behavior investigated by 57Fe Mossbauer spectroscopy rules out any valence fluctuations of Fe and the hyperfine field corroborates the magnetization data.
- Published
- 2015
234. Role of PC60BM in defect passivation and improving degradation behaviour in planar perovskite solar cells
- Author
-
Anand Singh, Sowjanya Pali, Rahul Ranjan, Belal Usmani, Sudhir Ranjan, Raju Kumar Gupta, and Ashish Garg
- Subjects
Kelvin probe force microscope ,Photoluminescence ,Materials science ,Passivation ,Renewable Energy, Sustainability and the Environment ,business.industry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Dielectric spectroscopy ,Titanium oxide ,Optoelectronics ,Grain boundary ,0210 nano-technology ,business ,Layer (electronics) ,Perovskite (structure) - Abstract
Titanium oxide (TiO2) is the most commonly employed electron transport layer (ETL) in planar perovskite solar cells (PSCs) structure (FTO/c-TiO2/CH3NH3PbI3/Spiro-OMeTAD/Ag). However, it suffers from defects such as oxygen vacancies and structural defects due to the formation of Ti3+ ions. While defects in TiO2 could play a role in determining the device performance, perovskite layer in PSCs also exhibits traps at interfaces and grain boundaries causing increased recombination losses lowering the power conversion efficiencies (PCE) of the devices. In this manuscript, we demonstrate the use of a thin interlayer of [6, 6]-phenyl-C60-butyric acid methyl ester (PC60BM) as a passivation layer between TiO2 and perovskite layer in planar PSC structure, as analysed using aging and stability studies. The study reveals that the quality of the interface between the constituent layers improves after introduction of PC60BM as passivation layer thus causing an enhancement in the performance of devices. The performance of the devices showed a peculiar behaviour when measured at different times with ~40% enhancement in PCE after 50 h followed by a drop when measured after 150 h. The initial improvement in the device performance was studied using photoluminescence (PL) spectroscopy which showed a blue shift in the emission while impedance spectroscopy measurements showed a significant reduction in charge transfer resistance after 50 h, aided by an improved band alignment as suggested by Kelvin probe force microscopy (KPFM). Further, we show that initiation of degradation in perovskite starts from interface instead of degradation in the bulk of perovskite layer.
- Published
- 2020
235. Improved ferroelectric response of pulsed laser deposited BiFeO3-PbTiO3 thin films around morphotropic phase boundary with interfacial PbTiO3 buffer layer
- Author
-
Ashish Garg, Rajesh Katoch, Kishor Kumar Sahoo, Rajeev Gupta, and Kumar Brajesh
- Subjects
010302 applied physics ,Phase boundary ,Materials science ,Analytical chemistry ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,Pulsed laser deposition ,Crystallinity ,Tetragonal crystal system ,symbols.namesake ,0103 physical sciences ,symbols ,Thin film ,0210 nano-technology ,Raman spectroscopy ,Monoclinic crystal system - Abstract
(1 − x)BiFeO3-xPbTiO3 (BF-xPT) is an interesting material for sensing and actuating devices with large polarization near the morphotropic phase boundary (MPB) (x = 0.30) in the bulk form. However, pulsed laser deposition (PLD) grown (BF-xPT) thin films usually show high electrical leakage and, hence, saturated ferroelectric hysteresis loops are only obtained at subzero temperatures. In this article, we report on high room temperature ferroelectric polarization with saturated hysteresis loops in pulsed laser deposited (BF-xPT) polycrystalline thin films of compositions near the MPB with the use of a thin buffer layer of PbTiO3 (PT). The thin films possessed a perovskite structure with excellent crystallinity and exhibit the presence of a monoclinic (Cm) phase (MA-type) for x = 0.20–0.25 and a mixture of a monoclinic (Cm) phase and a tetragonal (P4mm) phase for x = 0.30–0.35 compositions. The thin films with composition x = 0.25 exhibit a monoclinic phase and yield very large room temperature ferroelectric polarization (2Pr > 80μC/cm2), perhaps the highest room temperature ferroelectric polarization and excellent piezoelectric properties in PLD deposited (BF-xPT) thin films of near-MPB composition. Furthermore, the evolution of ferroelectricity with PT content, studied using room temperature Raman spectroscopy, reveals a correlation with lattice dynamics and stereochemical activity of Bi. Piezoforce domain analysis of the thin films reveals that ferroelectric polarization and electrical leakage in the thin films are intricately related to the type of domains present in the samples, viz., 180°, 109°, 90°, and 71° due to differences in the nature of the domain walls.
- Published
- 2020
236. Nanoparticle-based dry Powder Inhaler-Based Approach for Corona Virus Disease-2019 Treatment: An Update
- Author
-
Kumar Ajay, Ashish Garg, Neeraj Mishra, Sweta Garg, and Shevtank Bhatt
- Subjects
Drug ,Lung ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,media_common.quotation_subject ,Nanoparticle ,Virus diseases ,Pharmacology ,Dry-powder inhaler ,medicine.anatomical_structure ,medicine ,Respiratory system ,business ,media_common - Abstract
Corona virus disease-2019 (COVID 19) is a respiratory disorder caused by bunches of serious respiratory disorders (i.e., coughing, fever, and breathing problems) like severe acute respiratory syndrome (SARS), and the 79% homology as well as gene sequences are basically similar to SARS-CoV, thus the name of COVID-19 also be distinguish as SARS-CoV-2 on January 7th. Nanoparticles may also improve drug pulmonary efficacy by enhancing residence time, as a consequence the efficient mucus complexation between mucin and nanoparticles caused increment the rate of permeation and tissue uptake and displayed sustainable release property. Advances in device technology have led to the development of more efficient delivery systems capable of delivering larger doses and finer particles into the lung. As more efficient pulmonary delivery devices and sophisticated formulations become available, physicians, and health professionals will have a choice of a wide variety of device and formulation combinations that will target-specific cells or regions of the lung, avoid the lung's clearance mechanisms and be retained within the lung for longer periods. Dry powder inhalers (DPIs) exhibit many unique advantages that have contributed to the incredible growth in the number of DPI pharmaceutical products. To improve the performance, there are a relatively large number of DPI devices available for different inhalable powder formulations. The present review different type of nanoaparticles and DPIs used for the treatment of COVID 19 infections.
- Published
- 2020
237. Effect of Zn doping on structural and ferroelectric properties of GaFeO3for futuristic spintronic applications
- Author
-
Ashish Garg, Ashish Kumar Mall, Arun K. Singh, Nandni Sharma, Rajeev Gupta, Sanjeev Kumar, and Prince Jain
- Subjects
Materials science ,Spintronics ,Scanning electron microscope ,Doping ,Analytical chemistry ,chemistry.chemical_element ,Ferroelectricity ,symbols.namesake ,chemistry ,Impurity ,symbols ,Orthorhombic crystal system ,Gallium ,Raman spectroscopy - Abstract
In this paper, we have studied the effect of Zn doping on the structure, micro-structure and ferroelectric properties of GaFeO 3 . The syntheses of the samples were done using sol-gel technique. The X-ray diffraction (XRD) studies show the orthorhombic structure having space group Pc21n without any secondary phase or impurity, suggesting no change in structure due to the incorporation of Zn. The refined lattice parameters and unit cell volume increase upon Zn doping. Room temperature Raman spectroscopy data confirmed the incorporation of Zn in GaFeO 3 . Scanning electron microscope (SEM) images show the irregular shape of grains with average particle size of 0.9 $\mu\mathrm{m}$ and energy dispersive X-ray analysis (EDX) verified the composition of the compound. Further, the reduction in leakage current was observed upon Zn doping in GaFeO 3 , resulting in a more in ferroelectric behaviour.
- Published
- 2018
238. Heparin appended ADH-anionic polysaccharide nanoparticles for site-specific delivery of usnic acid
- Author
-
Sweta Garg, Sarita Rani, Umesh Gupta, Nitendra K. Sahu, Awesh K. Yadav, and Ashish Garg
- Subjects
Male ,Erythrocytes ,media_common.quotation_subject ,Adipates ,Pharmaceutical Science ,Antineoplastic Agents ,Apoptosis ,02 engineering and technology ,Polysaccharide ,030226 pharmacology & pharmacy ,Hemolysis ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,In vivo ,Zeta potential ,Animals ,Humans ,Internalization ,Cytotoxicity ,media_common ,Benzofurans ,Tube formation ,chemistry.chemical_classification ,Drug Carriers ,Chromatography ,Hematologic Tests ,Chemistry ,Heparin ,Cell Cycle ,Polysaccharides, Bacterial ,Usnic acid ,021001 nanoscience & nanotechnology ,Gellan gum ,Rats ,Drug Liberation ,A549 Cells ,Nanoparticles ,0210 nano-technology - Abstract
The intention of present research work is to formulate usnic acid (UA) loaded heparin modified gellan gum (HAG) nanoparticles (NPs). HAG copolymer based conjugation was synthesized and characterized by 1H NMR and FT-IR spectroscopy. Plain and UA loaded HAG NPs were prepared via nanoprecipitation technique. NPs were typified and further characterized for particle size, polydispersity index, entrapment efficiency, zeta potential, atomic force microscopy, differential scanning calorimetry, X-ray diffraction analysis, and in-vitro release. In-vitro tube formation assay, tumorsphere assay, autophagy assay, DNA cleavage assay, internalization by confocal and FACS based internalization analysis, caspase assay and cell cycle assay were performed for biological activity. Obtained experimental results explored that HAG NPs displayed a sustained release of UA (95.67% in 48 h) compared to gellan gum NPs (96.12% in 8 h). In cytotoxicity studies, UA loaded HAG NPs exhibited an enormous cytotoxic potential against A549 cancer cells. In the in vivo bio-distribution study, using albino rat model the free UA concentration was found 7.09 ± 0.9%, 2.7 ± 1.5%, 7.5 ± 2.1, 9.2 ± 2%, and 6.25 ± 1.3% post two hours of intravenous administration, however, in the case of UA loaded HAG NPs the obtained level was 4.1 ± 1.10, 7.7 ± 1.30%, 2.21 ± 0.29%, 1.85 ± 0.25%, 2.2 ± 0.78%, 2.9 ± 1.21% respectively, in heart, lung, liver, spleen, intestine and kidney. The overall anticancer study and result of internalization deciphered the higher anticancer potential of UA loaded HAG NPs.
- Published
- 2018
239. Enhanced efficiency and thermal stability of mesoscopic perovskite solar cells by adding PC70BM acceptor
- Author
-
Raju Kumar Gupta, Anand Singh, Sudhir Ranjan, Belal Usmani, Rahul Ranjan, Hasitha Weerasinghe, and Ashish Garg
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,Photovoltaic system ,Energy conversion efficiency ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Acceptor ,Grain size ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Chemical engineering ,law ,Solar cell ,Grain boundary ,Thermal stability ,Charge carrier ,0210 nano-technology - Abstract
Perovskite-based solar cells (PSCs) have emerged as a very promising solar photovoltaic technology with fivefold increase observed in the device efficiency within less than 10 years of its inception. The efficiency of these solar cells is strongly affected by the quality of perovskite layer surface coverage and its grain size. Although use of antisolvents such as chlorobenzene has been used to treat methylammonium lead iodide (CH3NH3PbI3) resulting in grain size of ca. 200–300 nm, one still needs to minimize the grain boundaries to reduce their impact on recombination. In this study, we have successfully incorporated [6, 6]-phenyl-C70-butyric acid methyl ester (PC70BM) acceptor as an additive in the perovskite layer of the mesoscopic solar cell devices, which not only leads to the formation of larger grains with fewer grain boundaries resulting in reduced charge carriers recombination, the band alignment between CH3NH3PbI3 and TiO2 was also found to improve. The device having the optimum PC70BM concentration in perovskite showed enhanced power conversion efficiency (PCE) due to improvement in current density (JSC) and fill-factor (FF), correlated to the decrease in charge transfer resistance (RCT). The devices using PC70BM additive exhibit over 15% improvement in the power conversion efficiency or PCE (15.5% for PC70BM containing device and 13.3% PCE for the reference device with no acceptor additive). More importantly, the device containing PC70BM acceptor additive, retained ca. 75% of the original PCE for 250 h when kept at 85 °C without encapsulation in an ambient at 20% RH.
- Published
- 2019
240. Unilateral lung agenesis, hiatal hernia and atrioventricular septal defect: a rare combination of congenital anomalies
- Author
-
Josaura Fernandez-Sanchez, Sethuraman Swaminathan, Sudheer R. Gorla, and Ashish Garg
- Subjects
Adult ,Lung Diseases ,medicine.medical_specialty ,Time Factors ,Unusual Association of Diseases/Symptoms ,030204 cardiovascular system & hematology ,Hiatal hernia ,03 medical and health sciences ,0302 clinical medicine ,Pregnancy ,medicine ,Humans ,Abnormalities, Multiple ,Atrioventricular Septal Defect ,Lung ,Referral and Consultation ,Herniorrhaphy ,Gastrostomy ,Left lung ,business.industry ,Heart Septal Defects ,Infant, Newborn ,Congenital malformations ,General Medicine ,Unilateral lung agenesis ,respiratory system ,medicine.disease ,Pulmonary hypertension ,Surgery ,respiratory tract diseases ,Hernia, Hiatal ,Treatment Outcome ,030228 respiratory system ,LUNG AGENESIS ,Agenesis ,Female ,business ,Infant, Premature - Abstract
Unilateral lung agenesis is a relatively rare congenital anomaly with a reported incidence of 1 in 15 000 births. It is frequently associated with other congenital malformations. Some of the sequelae of lung agenesis are potentially life-threatening. Here, we report a case of left lung agenesis in association with hiatal hernia and atrioventricular septal defect, a rare combination of anomalies which have not been described previously in the literature.
- Published
- 2018
241. Application of Artificial Neural Networks for Optimizing Operating Conditions of a Chemical Process
- Author
-
Jennifer Pounjeba Philip Christopher, Kathiravan Srinivasan, Chang-Tang Chang, Ashish Garg, Aswani Kumar Cherukuri, and Bor-Y ann Chen
- Subjects
Artificial neural network ,Process (engineering) ,Computer science ,business.industry ,Deep learning ,Computer Science::Neural and Evolutionary Computation ,010401 analytical chemistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Machine learning ,computer.software_genre ,01 natural sciences ,0104 chemical sciences ,Data modeling ,Nonlinear system ,Salient ,Feature (machine learning) ,Artificial intelligence ,0210 nano-technology ,business ,computer - Abstract
Considering that there are a significantly large number of variables and several steps, in a chemical process, modeling of such a method is non-trivial. Moreover, the process has a non-linear and transience dependence on the conditions. Artificial Neural Network (ANN) and Deep Learning methods based on ANNs have been widely recognized as one of the most influential modeling and learning techniques for nonlinear systems. The salient feature of ANN-based modeling is that the detailed mathematical information about the process steps is not pre-determined or fed to the system; instead, the learning takes place by using the training examples. Therefore, it is not surprising that ANN-based modeling is used for predicting the outcomes of chemical processes. Experimental data will be required to train the model and also to validate the predictions.
- Published
- 2018
242. A fluorene-core-based electron acceptor for fullerene-free BHJ organic solar cells-towards power conversion efficiencies over 10
- Author
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Barkha Tyagi, Vinay Gupta, Suman, Anirban Bagui, Surya Prakash Singh, and Ashish Garg
- Subjects
Materials science ,Fullerene ,Organic solar cell ,02 engineering and technology ,Fluorene ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Materials Chemistry ,chemistry.chemical_classification ,Photovoltaic system ,Energy conversion efficiency ,Metals and Alloys ,General Chemistry ,Polymer ,Electron acceptor ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Rhodanine ,chemistry ,Ceramics and Composites ,0210 nano-technology - Abstract
A small molecule non-fullerene electron acceptor (SMNFEA), bearing a furan π-spacer and dicyano-n-hexyl rhodanine as flanking groups, was designed and synthesized for organic solar cell applications. Organic photovoltaic devices based on FRdCN2 and PTB7-Th polymer donors exhibited a highly improved efficient power conversion efficiency of 10.7%, which is the highest so far for OSCs fabricated from fluorene-core-based SMNFEAs.
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- 2018
243. It Is Not Always Sepsis: Fatal Tachypnea in a Newborn
- Author
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Michael Keenaghan, Ashish Garg, Rachel Levene, and Elza Pollak-Christian
- Subjects
Pediatric emergency ,Pediatrics ,medicine.medical_specialty ,Heart disease ,business.industry ,Coarctation of the aorta ,lcsh:RJ1-570 ,lcsh:Pediatrics ,Case Report ,General Medicine ,respiratory system ,medicine.disease ,Tachypnea ,Sepsis ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,030225 pediatrics ,medicine ,030212 general & internal medicine ,medicine.symptom ,Prostaglandin E1 ,business - Abstract
Coarctation of the aorta (CoA) is a congenital cardiac malformation that is well understood. Despite being well characterized, CoA is a commonly missed congenital heart disease (CHD) during the newborn period. We report a full-term nine-day-old male who presented to the pediatric emergency department (ED) with isolated tachypnea. After an initial sepsis workup, subsequent investigations revealed critical CoA. Because the primary workup focused on sepsis, there was a significant delay in prostaglandin E1 (PGE1) initiation. This case illustrates the importance of early CoA recognition and timely initiation of PGE1in newborns who present with suspected sepsis along with tachypnea.
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- 2018
244. Acute Myocardial Injury in Association with Metformin Toxicity
- Author
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Sethuraman Swaminathan, Nataly Judith Sánchez-Solano, Ashish Garg, and Sudheer R. Gorla
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medicine.medical_specialty ,endocrine system diseases ,business.industry ,digestive, oral, and skin physiology ,Type 2 Diabetes Mellitus ,nutritional and metabolic diseases ,030209 endocrinology & metabolism ,030204 cardiovascular system & hematology ,Critical Care and Intensive Care Medicine ,medicine.disease ,Metformin ,03 medical and health sciences ,0302 clinical medicine ,Large dose ,Internal medicine ,Lactic acidosis ,Pediatrics, Perinatology and Child Health ,Toxicity ,Oral hypoglycemic agents ,Medicine ,Ingestion ,business ,medicine.drug - Abstract
Metformin is one of the most commonly used oral hypoglycemic agents in the treatment of type 2 diabetes mellitus. Toxicity related to accidental or intentional ingestion of metformin is well reported in the pediatric literature. We report a case of transient acute myocardial injury documented by biochemical and electrophysiological evidences in an adolescent male who presented with intentional ingestion of a large dose of metformin. To our knowledge, this is the first such case of documented reversible myocardial injury in relation to metformin toxicity to be reported in the pediatric literature.
- Published
- 2018
245. Study of structural and magnetic characterization of polycrystalline Y0.5Ho0.5CrO3
- Author
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Rajeev Gupta, Ashish Kumar Mall, and Ashish Garg
- Subjects
Materials science ,Condensed matter physics ,Rietveld refinement ,Magnetometer ,Phonon ,law.invention ,Condensed Matter::Materials Science ,Magnetization ,symbols.namesake ,Ferromagnetism ,law ,Condensed Matter::Superconductivity ,symbols ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Orthorhombic crystal system ,Raman spectroscopy - Abstract
A polycrystalline ceramic sample of Y0.5Ho0.5CrO3 was studied using powder X-ray diffraction, Raman spectroscopic and dc magnetometry measurement to understand the structural and magnetic properties. The Rietveld refinement of X-ray data suggests sample crystallized in Pnma orthorhombic structure without formation of any secondary phases confirming their phase-pure nature. However, Raman study shows a prominent effect of Ho doping in low wavenumber Raman active phonon modes. Further, M-T measurement shows magnetic phase transition (TN) at 141 K and a negative value of Curie-Weiss temperature suggesting an antiferromagnetic system. Subsequent, the appearance of the clear opening in the M-H loop below TN is an evidence of the appearance of a weak ferromagnetic component in the low- temperature regime while the magnetization increases linearly in the high magnetic field regime suggest antiferromagnetic component.A polycrystalline ceramic sample of Y0.5Ho0.5CrO3 was studied using powder X-ray diffraction, Raman spectroscopic and dc magnetometry measurement to understand the structural and magnetic properties. The Rietveld refinement of X-ray data suggests sample crystallized in Pnma orthorhombic structure without formation of any secondary phases confirming their phase-pure nature. However, Raman study shows a prominent effect of Ho doping in low wavenumber Raman active phonon modes. Further, M-T measurement shows magnetic phase transition (TN) at 141 K and a negative value of Curie-Weiss temperature suggesting an antiferromagnetic system. Subsequent, the appearance of the clear opening in the M-H loop below TN is an evidence of the appearance of a weak ferromagnetic component in the low- temperature regime while the magnetization increases linearly in the high magnetic field regime suggest antiferromagnetic component.
- Published
- 2018
246. Synthesis, growth, and characterizations of CuO single crystal
- Author
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Ashish Kumar Mall, Prince Kumar, Ashish Garg, and Rajeev Gupta
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Diffraction ,Crystal ,symbols.namesake ,Magnetization ,Crystallography ,Materials science ,Scanning electron microscope ,symbols ,Raman spectroscopy ,Microstructure ,Single crystal ,Monoclinic crystal system - Abstract
In this paper, we have synthesized the high-quality cupric oxide (CuO) single crystals using flux growth method. The crystals were characterized using the X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX), Raman spectroscopy and magnetometry. The XRD results confirm that crystals exhibit single phase monoclinic structure. It has been confirmed subsequent using EDX analysis. Microstructure investigation shows columnar growth with stacking boundary. Further, Raman spectroscopic analysis of the CuO single crystal shows that Ag mode is found at 298 cm-1 which polarized along the one axes of the crystal while other two Bg mode were found at 346 cm-1 (B1g) and 632 cm-1 (B2g) respectively. From magnetization measurement, we observed magnetic transition at 235 K. Temperature dependent magnetization shows a bifurcation between ZFC-FC branches at 235 K and a cusp around 125 K, make a possibility of spin-glasses behavior.
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- 2018
247. National Survey of Pediatric Care Providers: Assessing Time and Impact of Coding and Documentation in Physician Practice
- Author
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Ninad Desai, Anshul Arora, Ashish Garg, and Munaza Rizvi
- Subjects
medicine.medical_specialty ,business.industry ,Medical record ,Medical practice ,Patient care ,03 medical and health sciences ,0302 clinical medicine ,Documentation ,030220 oncology & carcinogenesis ,Family medicine ,Pediatrics, Perinatology and Child Health ,Medicine ,Job satisfaction ,In patient ,Pediatric care ,business ,030215 immunology ,Coding (social sciences) - Abstract
Introduction Coding and billing are an essential part of current medical practice. Much of a physician’s day is spent maintaining the patient health record. Not only has this negatively impacted job satisfaction for residents and attending physicians, but it may also be significantly reducing available time for patient care, negatively impacting patient outcomes. In a 2013 poll, 92% of residents reported that clinical documentation obligations are excessive and 73% of residents reported compromises in patient care by these requirements. In 2006, according to a survey of surgical residents …
- Published
- 2018
248. It’s Not Always Sepsis; Fatal Tachypnea in a Newborn
- Author
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Ashish Garg, Rachel Levene, and Elza Pollak-Christian
- Subjects
Pediatric emergency ,business.industry ,medicine.disease ,Tachypnea ,Respiratory support ,Sepsis ,Broad spectrum ,chemistry.chemical_compound ,chemistry ,Anesthesia ,Pediatrics, Perinatology and Child Health ,medicine ,Respiratory system ,medicine.symptom ,Femoral pulses ,business ,Prostaglandin E1 - Abstract
Case Report: A nine day old term male presented to the pediatric emergency room (ER) with isolated tachypnea without fever or upper respiratory symptoms. Full sepsis protocol was initiated and neonate was treated with broad spectrum antibiotics and acyclovir, after obtaining pan-cultures. Chest X-ray was normal. For worsening tachypnea infant was placed on CPAP for respiratory support. Neonate was admitted to the PICU and subsequently noted to have weak femoral pulses. Lower limb blood pressures at that time were undetectable. Ten hours post initial presentation to the ER, Prostaglandin E1 (PGE1) was started in …
- Published
- 2018
249. List of Contributors
- Author
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Sambandam Anandan, Subramanian Arulmani, Muthupandian Ashokkumar, Nilofar Asim, Marzieh Badiei, Bhaskar Bethi, Bharat A. Bhanvase, Wei Chen, Sanjay J. Dhoble, Miroslav D. Dramićanin, Ashish Garg, Tamara V. Gavrilović, Ankur Goswami, Sarang P. Gumfekar, Raju Kumar Gupta, Chandrakant R. Holkar, Ananda J. Jadhav, Saransh S. Jain, Dragana J. Jovanović, Gang-Juan Lee, Minmin Liu, Masita Mohammad, Govind B. Nair, Vijay B. Pawade, Dipak V. Pinjari, Rajesh Kumar Polagani, Jai Prakash, Rahul Ranjan, Paresh H. Salame, Govindasamy Sathiyan, Prosenjit Sen, Anand Singh, Shirish H. Sonawane, Prashant L. Suryawanshi, N. Thejo Kalyani, Jerry J. Wu, and Chunmei Zhang
- Published
- 2018
250. Recent Progress on Hole-Transporting Materials for Perovskite-Sensitized Solar Cells
- Author
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Jai Prakash, Raju Kumar Gupta, Rahul Ranjan, Anand Singh, Govindasamy Sathiyan, and Ashish Garg
- Subjects
Materials science ,Exciton ,Photovoltaic system ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,law ,Solar cell ,0210 nano-technology ,Perovskite (structure) - Abstract
Perovskite-sensitized solar cells have been the subject of intense research over the past several years because they are promising as high-efficiency devices. Improvements in the function and longevity of these devices hinges on the advent and application of new material components involved, including TiO 2 , perovskite, and the hole-transporting material (HTM). The hole-transporting layer often comprises an organic π-functional material and plays a key role in hole separation, decreasing excitons regeneration and enhancing charge-transporting properties. In this chapter, we focus on the evolution of organic HTMs as a lynchpin for improving photovoltaic properties of perovskite-sensitized solar cell devices. Recent developments in organic HTMs including the synthesis and application of novel structural architectures, their effect in modulation of optical and electrochemical properties, and ultimately, their influence on device performance parameters will be discussed. Valuable insights obtained by the correlation of HTM molecular design aspects and device performance will be discussed along with the outlook in this area.
- Published
- 2018
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