Flexible High-Performance Lead-Free Na_0.47K_0.47Li_0.06NbO₃ Microcube-Structure-Based Piezoelectric Energy Harvester

Gupta, Manoj Kumar,Kim, Sang-Woo,Kumar, Binay American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.3

<P>Lead-free piezoelectric nano- and microstructure-based generators have recently attracted much attention due to the continuous demand of self-powered body implantable devices. We report the fabrication of a high-performance flexible piezoelectric microgenerator based on lead-free inorganic piezoelectric Na0.47K0.47Li0.06NbO3 (NKLN) microcubes for the first time. The composite generator is fabricated using NKLN microcubes and polydimethylsiloxane (PDMS) polymer on a flexible substrate. The flexible device exhibits excellent performance with a large recordable piezoelectric output voltage of 48 V and output current density of 0.43 mu A/cm(2) under vertical compressive force of 2 kgf, for which an energy conversion efficiency of about 11% has been achieved. Piezoresponse and ferroelectric studies reveal that NKLN microcubes exhibited high piezoelectric charge coefficient (d(33)) as high as 460 pC/N and a well-defined hysteresis loops with remnant polarization and coercive field of 13.66 mu C/cm(2) and 19.45 kV/cm, respectively. The piezoelectric charge generation mechanism from NKLN microgenerator are discussed in the light of the high d33 and alignment of electric dipoles in polymer matrix and dielectric constant of NKLN microcubes. It has been demonstrated that the developed power generator has the potential to generate high electric output power under mechanical vibration for powering biomedical devices in the near future.</P>

Highly efficient flexible piezoelectric nanogenerator and femtosecond two-photon absorption properties of nonlinear lithium niobate nanowires

Gupta, Manoj Kumar,Aneesh, Janardhanakurup,Yadav, Rajesh,Adarsh, K. V.,Kim, Sang-Woo American Institute of Physics 2017 JOURNAL OF APPLIED PHYSICS - Vol.121 No.17

Two-Dimensional Vanadium-Doped ZnO Nanosheet-Based Flexible Direct Current Nanogenerator

Gupta, Manoj Kumar,Lee, Ju-Hyuck,Lee, Keun Young,Kim, Sang-Woo American Chemical Society 2013 ACS NANO Vol.7 No.10

<P>Here, we report the synthesis of lead-free single-crystalline two-dimensional (2D) vanadium(V)-doped ZnO nanosheets (NSs) and their application for high-performance flexible direct current (DC) power piezoelectric nanogenerators (NGs). The vertically aligned ZnO nanorods (NRs) converted to NS networks by V doping. Piezoresponse force microscopy studies reveal that vertical V-doped ZnO NS exhibit typical ferroelectricity with clear phase loops, butterfly, and well-defined hysteresis loops with a piezoelectric charge coefficient of up to 4 pm/V, even in 2D nanostructures. From pristine ZnO NR-based NGs, alternating current (AC)-type output current was observed, while from V-doped ZnO NS-based NGs, a DC-type output current density of up to 1.0 μAcm<SUP>–2</SUP> was surprisingly obtained under the same vertical compressive force. The growth mechanism, ferroelectric behavior, charge inverted phenomena, and high piezoelectric output performance observed from the V-doped ZnO NS are discussed in terms of the formation of an ionic layer of [V(OH)<SUB>4</SUB><SUP>–</SUP>], permanent electric dipole, and the doping-induced resistive behavior of ZnO NS.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-10/nn403428m/production/images/medium/nn-2013-03428m_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn403428m'>ACS Electronic Supporting Info</A></P>

Analysis of tribological behavior of Al/Gr/MoS2 surface composite fabricated by friction stir process

Gupta Manoj Kumar 한국탄소학회 2020 Carbon Letters Vol.30 No.4

The life span of many engineering components depends upon their surface properties. The improved surface properties of the materials are essential for enhancing the mechanical and tribological performance of the material. In many applications, the components required only improved surface properties without changing the entire volume properties of the material. The friction stir process (FSP) is a novel processing technique for the fabrication of such surface composites. In the present investigation, the surface composites were fabricated by incorporating molybdenum disulfde (MoS2) and graphite (Gr) as reinforcement on the surface of aluminum alloy (Al 1120) through the friction stir process (FSP) at tool rotational speed of 1400 rpm and tool feed rate of 40 mm/min process parameters using square profle FSP tool. The tribological behaviors of fabricated surface composites were calculated by using a pin on disk tribometer. It was observed that the wear resistance of surface composites improved as compared to the matrix material.

Assessment of the Antiulcer Potential of Moringa oleifera Root-Bark Extract in Rats

Manoj Kumar Choudhary,Surendra H. Bodakhe,Sanjay Kumar Gupta 사단법인약침학회 2013 Journal of Acupuncture & Meridian Studies Vol.6 No.4

In the present study, an ethanolic root-bark extract of Moringa oleifera (MO) was examined for its antiulcer potential in albino Wistar rats using two experimental models: ethanol-induced and pylorus ligation-induced gastric ulceration. The extract was orally administered at three different doses (150, 350, and 500 mg/kg) for 15 consecutive days. The antiulcer effects in rats treated with different doses of the extract and omeprazole (30 mg/kg, p.o.) were determined and compared statistically with the antiulcer effects in the control rats treated with saline (NaCl, 0.9%). The MO at doses of 350 and 500 mg/kg decreased the ulcer index significantly as compared to the control group (p < 0.01). The percentage protections against gastric ulcers were 82.58%, 85.13%, and 86.15% for MO doses of 150, 350, and 500 mg/kg, respectively, in the pylorus-ligated ulcer model and 55.75%, 59.33%, and 78.51%, respectively, in the ethanol-induced ulcer model. The MO significantly reduced the free acidity, total acidity, and ulcer index (p < 0.01) and increased the pH of gastric content compared with the control group. This study suggests that MO possesses valuable antiulcer, antisecretory, and cytoprotective activity. Thus, an ethanolic root-bark extract of Moringa oleifera can be used as source for an antiulcer drug.

Thermokinetics behavior of epoxy adhesive reinforced with low viscous aliphatic reactive diluent and nano-fillers

Amit Kumar Singh,Bishnu Prasad Panda,Smita Mohanty,Sanjay Kumar Nayak,Manoj Kumar Gupta 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.11

The current study reports the effect of low viscous aliphatic reactive diluent (RD), MWCNT and VGCF on the curing kinetics of amine cured epoxy adhesive system employing non-isothermal differential scanning calorimetric (DSC) technique. Non-isothermal DSC thermograms of epoxy adhesive were studied at various heating rates: 5, 10 and 15 oC/min. The decrease in the exothermic peak height with the introduction of MWCNTs and VGCFs was taken as proof of the acceleration effect of nano-fillers on the epoxy-amine curing reaction. Also, increased Tonset, TP and ΔHcurs values were observed for epoxy/RD adhesive system at all heating rates. The value of activation energy (Ea) was determined using Kissinger and Flynn-Wall-Ozawa methods. Experimental results showed that the addition of 10 wt% RD increased the Ea from 60 to 63 kJ/mol on account of the reduced viscosity, allowing better contact of resin with the curing agent. Furthermore, MWCNTs have an accelerating effect on the cure kinetics that does not change the autocatalytic cure reaction mechanism of epoxy resin. It was also found that the addition of MWCNT and VGCF decreases the overall degree of conversion, as evident with lower ΔHcure and Ea of the cured adhesive when compared with epoxy/RD system. The dependency of Ea on degree of conversion ranging from α =0.1 to 0.9was also investigated. The two normalized functions y(α) and z(α) were also considered in order to study the complex curing mechanism. The kinetic parameters m, n and lnA were obtained by using two parameter autocatalytic Sestak-Berggren model. The curves revealed good agreement between experimentally determined and theoretically obtained MWCNT/VGCF reinforced epoxy adhesive systems.

Safety Profile and Therapeutic Efficacy of One Cycle of Lu177-PSMA in End-Stage Metastatic Castration-Resistant Prostate Cancer Patients with Low Performance Status

Manoj Gupta,Partha Sarathi Choudhury,Sudhir Rawal,G. Karthikeyan,Vineet Talwar,Kumar Deep Dutta,Amitabh Singh 대한핵의학회 2019 핵의학 분자영상 Vol.53 No.6

Purpose The aimof this study was to evaluate safety and therapeutic efficacy of lutetium 177 prostate-specific membrane antigen (Lu-177-PSMA) in metastatic castration-resistant prostate cancer (mCRPC) patients with low performance status. Methods Twenty-two patients already treated with anti-androgens and docetaxel were enrolled for one cycle of Lu-177-PSMA therapy. Haemoglobin, total leukocyte counts, platelets and serum creatinine for toxicity profile while prostate specific antigen (PSA), Eastern Cooperative Oncology Group (ECOG) performance status, visual analogue scale (VAS) and analgesic quantification scale (AQS) for therapeutic efficacy were recorded pre and 8 weeks post therapy.Wilcoxon signed-rank and ANOVA tests were used for statistical analysis. Results Partial response (PR), stable disease (SD) and progressive disease (PD) for PSAwere seen in 5 (22.7%), 13 (59.1%) and 4 (18.2%) patients respectively treated with mean 6.88 GBq dose of Lu-177-PSMA. 8/22 (36.4%) patients showed ≥ 30% drop in PSA. Grade 3 haemoglobin toxicity was seen in 5/22 (22.7%) patients. No patient developed grade 4 haemoglobin toxicity. No patients had grade 3 or 4 leukocytopenia or thrombocytopenia. Wilcoxon signed-rank test showed statistical significant (P < 0.05) difference in pre and post treatment ECOG, VAS, and AQS scores. The ANOVA test showed statistically significant difference in mean doses of Lu-177-PSMA used in three PSA response groups while difference was non-significant for other variables. Conclusion We concluded that Lu-177-PSMA therapy has adequate pain palliation in end-stage mCRPC patients with low performance status and it has a potential to become effective therapeutic option in properly selected patients.

Early Transneuronal Degeneration in Dyke-Davidof-Masson Syndrome

Anu Gupta,Manoj Kumar Goyal,Parampreet Singh,Vivek Lal 대한신경과학회 2016 Journal of Clinical Neurology Vol.12 No.1

Effects of Long-term Use of Depo-medroxyprogesterone Acetate on Lipid Metabolism in Nepalese Women

Binod Kumar Yadav,Rajesh Kumar Gupta,Prajwal Gyawali,Rojeet Shrestha,Bibek Poudel,Manoj Sigdel,Bharat Jha 대한진단검사의학회 2011 Annals of Laboratory Medicine Vol.31 No.2

Various synthetic progestogens that are used as contraceptives have been reported to influence lipid and lipoprotein fractions differently. Depo-medroxyprogesterone acetate (DMPA), a synthetic progestogen, is used by Nepalese women as a contraceptive agent. Our study aims to determine the effects of long-term use of DMPA on lipid metabolism. We performed this study on 60 healthy Nepalese women who had been using DMPA for more than 2 yr and age- and weight-matched control subjects who were not using hormonal contraceptives. Fasting blood samples were collected from the subjects for the estimation of total cholesterol (TC) and triglyceride (TG) levels, and the levels of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were estimated using the Friedewald’s equation. TC and LDL-C levels in DMPA users were significantly higher than those in non-users. Our study concluded that DMPA use induces lipid metabolism changes that can increase the risk of cardiovascular diseases.

Analysis of Various COVID-19 Prediction Techniques

Rakesh Kumar Arora,Manoj Kumar Gupta,Bhoopesh Singh Bhati 대한전자공학회 2021 IEIE Transactions on Smart Processing & Computing Vol.10 No.4

There is no precise treatment available for COVID-19, but treatment of a number of signs/symptoms is possible. This treatment is provided in accordance with the clinical position of the patient. Furthermore, supplementary care is proven as efficient for infected people. COVID-19 prediction techniques follow various steps, which include dataset collection, pre-processing, feature extraction, and classification. Numerous COVID-19 prediction techniques have been proposed in the literature. In this paper, various techniques are systematically reviewed on the basis outcomes, advantages, and disadvantages.