Investigation of interface magnetism of complex oxide heterostructures using polarized neutron reflectivity

Surendra Singh,S. Basu 한국물리학회 2017 Current Applied Physics Vol.17 No.5

Multilayered structures with artificial oxide hetero-interfaces have recently been dominating the field of new states of matter. The unexpected properties and related functionalities at the interface of complex oxide heterostructures as a consequence of the symmetry breaking, electronic reconstruction etc., make these complex oxide interfaces particularly challenging for understanding the fundamental mechanism and interaction across the interfaces. Magnetic modulation, novel magnetic coupling and emerging interface induced magnetization at the interfaces of complex oxide heterostructures have made the search for their technological applications as an intense field of research in recent time. However to study the structure and magnetism in such interfaces require tools with interface specificity. Polarized neutron reflectivity is a non-destructive technique which has played a decisive role in investigation of interfacial magnetic structures and in understanding the underlying physics in this rapidly developing field. This article presents a review of some recent experimental results on emerging magnetization at the interfaces of complex oxide heterostructures specifically investigated using polarized neutron reflectivity.

Structural, magnetic and dielectric study of Fe2O3 nanoparticles obtained through exploding wire technique

Singh Surendra,Goswami Navendu 한국물리학회 2021 Current Applied Physics Vol.22 No.-

We propose an exploding wire technique based facile approach to prepare Fe2O3 nanoparticles in ambient conditions. TG-DSC analysis of the prepared precursor (Fe(OH)3) nanoparticles were done. The phase, lattice parameter and the average crystallite size were evaluated through X-ray diffraction analysis. The morphology of prepared nanoparticles was studied by scanning electron microscopy and Transmission electron microscope. The functional group formation of Fe2O3 nanoparticles and intrinsic stretching vibration bands of Fe–O were estimated through FTIR analysis. The direct band gap of Fe2O3 nanoparticles occurring in conjunction with indirect band gaps was established via Tauc plot. The magnetic parameters were studied through M¨ossbauer spectroscopy, ESR, M-H and M-T plot analysis. The attributes of dielectric behaviour like dielectric constant (ε′ ), loss tangent (tan δ), dielectric loss (ε′′ ) and alternating current (AC) conductivity (σAC) were measured at various temperatures in the frequency range of 10 Hz-106 KHz.

ON DECOMPOSITION OF RECURRENT CURVATURE TENSOR FIELDS IN GENERALISED FINSLER SPACES

Singh, Surendra Pratap Department of Mathematics 1975 Kyungpook mathematical journal Vol.15 No.2

GANGA RIVER : OPPORTUNITIES AND THREATS

Surendra Singh Nagdali 서울행정학회 2014 서울행정학회 학술대회 발표논문집 Vol.2014 No.7

Cinnamaldehyde Attenuates Cataractogenesis via Restoration of Hypertension and Oxidative Stress in Fructose-Fed Hypertensive rats

Singh, Amrita,Ahmad Khan, Samsroz,Choudhary, Rajesh,Bodakhe, Surendra Haribhau KOREAN PHARMACOPUNCTURE INSTITUTE 2016 Journal of pharmacopuncture Vol.19 No.2

Objectives: Several studies have revealed that systemic hypertension is strongly associated with cataractogenesis. However, the pathophysiology and treatment is often unclear. In this study, we evaluated the anti-cataractogenic effect of cinnamaldehyde (CA), a natural organic compound, in rats with fructose-induced hypertension. Methods: The rats were divided into six groups. For six weeks, the normal group received a suspension of 0.5% carboxy methyl cellulose (10 mL/kg/day, p.o.) while five other groups received a 10% (w/v) fructose solution in their drinking water to induce hypertension. By the end of the third week hypertension had been induced in all the animals receiving fructose. From the beginning of the fourth week to the end of the sixth week, one of those five groups (control) continued to receive only 10% (w/v) fructose solution, one group (standard) received ramipril (1 mg/kg/day, p.o.) plus 10% (w/v) fructose solution, and three groups (experimental) received CA at doses of 20, 30, and 40 mg/kg/day p.o., plus 10% (w/v) fructose solution. Blood pressure was measured weekly using a non-invasive blood pressure apparatus. After six weeks, the animals were sacrificed, and the anti-cataractogenic effects on the eye lenses were evaluated. Results: Administration of fructose elevated both the systolic and the diastolic blood pressures, which were significantly reduced by CA at all dose levels. In the control group, a significant increase in the malonaldehyde (MDA) level and decreases in the total protein, $Ca^{2+}$adenosine triphosphate (ATP)ase activity, glutathione peroxidase, catalase, superoxide dismutase and glutathione levels, as compared to the normal group, were observed. Administration of CA at all doses significantly restored the enzymatic, non-enzymatic, antioxidants, total protein, and $Ca^{2+}$ATPase levels, but decreased the MDA level, as compared to the control group. Conclusion: The present study revealed that CA modulated the antioxidant parameters of the serum and lens homogenates in hypertension-induced cataractogenic animals.

Temporal Variation in Tiger Population in a Semi-Arid Habitat in India

Singh, Randeep,Pandey, Puneet,Qureshi, Qamar,Sankar, Kalyanasundaram,Krausman, Paul R.,Goyal, Surendra Prakash National Institute of Ecology 2022 국립생태원회보(PNIE) Vol.3 No.3

Understanding temporal variations in wildlife populations is a prerequisite for conservation planning of wide-ranging species such as tigers (Panthera tigris). We determined the temporal variation in abundance, population growth, and sex ratios at different age and sex stages for a tiger population in Ranthambhore Tiger Reserve, India from November 2007 to February 2011 using motion-sensing cameras. We identified 19 male and 21 female tigers from stripe patterns during 16,110 trap nights within an area covering 233 km². The annual abundance of the population varied from 34.9 (mean)±3.8 (SE) to 23.9±1.5, with a declining trend in the mean annual change of abundance (-12%). The density of adult females remained stable across the study duration, but the densities of adult males and non-breeding tigers fluctuated. The sex ratio was female-biased (0.58 males/female) for breeding tigers and male-biased (1.74 males/female) for non-breeding tigers. Our results reinforce the importance of long-term studies for monitoring the naturally occurring processes in populations to develop population indicators and identify reliable baseline information for conservation and management planning of populations.

Performance Enhancing of Spray Formed Al/Graphite Alloy Composite by Rolling

Surendra Kumar Chourasiya,Gaurav Gautam,Devendra Singh 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6

The present study outlines the effect of warm rolling on the Al/Graphite alloy composite to investigate its effect on mechanicalperformance. The Al/Graphite alloy composite has been fabricated by the spray forming process and has been subjectedto the rolling at 250 °C with varying reduction. The rolled composite has been studied under different characterizationtechniques such as X-ray fluorescence (XRF), optical microscopy, scanning electron microscopy with energy dispersivespectroscopy (EDS) and tensile tester. The XRF and EDS results indicate that the Al/Graphite alloy composite is successfullyformed. The microscopy results show that the grain size of α-aluminium and agglomeration of the particles refine byrolling and they continuously decrease with an increase in rolling reduction. The strength and percentage elongation of thecomposite improves by rolling and they continuously increase with an increase in rolling reduction. Further, the fracturesurface study has also been performed and it indicates that the fracture of the composite alters from brittle to ductile modewith an increase in rolling reduction. The appeared fracture surface of the composite has also been correlated with the producedmicrostructure and the tensile properties.

In Vitro Antioxidant and Free Radical Scavenging Activity of Nardostachys jatamansi DC.

Surendra Kumar Sharma,Ajay Pal Singh 사단법인약침학회 2012 Journal of Acupuncture & Meridian Studies Vol.5 No.3

In this study, the antioxidative potential of a hydroalcoholic extract of Nardostachys jatamansi rhizomes (NJE) was evaluated by various antioxidant assays, including antioxidant capacity by the phosphomolybdenum method, total antioxidant activity in linoleic acid emulsion systems, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, hydroxyl radicals, nitric oxide (NO) scavenging, metal chelating and reducing power activity. These various antioxidant activities were compared to standard antioxidants such as butylated hydroxytoluene, tocopherol, catechin and L-ascorbic acid. Total phenolic and flavonoid content of NJE was also determined by a colorimetric method. The extract exhibited high reduction capability and powerful free radical scavenging, especially against DPPH and superoxide anions as well as a moderate effect on NO. Moreover, the peroxidation inhibiting activity of NJE was demonstrated in the linoleic acid emulsion system. The results obtained in the present study clearly established the antioxidative potency of Nardostachys jatamansi, which may account for some of the medical claims attributed to this plant.

Cinnamaldehyde Attenuates Cataractogenesis via Restoration of Hypertension and Oxidative Stress in Fructose-Fed Hypertensive rats

Amrita Singh,Samsroz Ahmad Khan,Rajesh Choudhary,Surendra Haribhau Bodakhe 대한약침학회 2016 Journal of pharmacopuncture Vol.19 No.2

Objectives: Several studies have revealed that systemic hypertension is strongly associated with cataractogenesis. However, the pathophysiology and treatment is often unclear. In this study, we evaluated the anti-cataractogenic effect of cinnamaldehyde (CA), a natural organic compound, in rats with fructose-induced hypertension. Methods: The rats were divided into six groups. For six weeks, the normal group received a suspension of 0.5% carboxy methyl cellulose (10 mL/kg/day, p.o.) while five other groups received a 10% (w/v) fructose solution in their drinking water to induce hypertension. By the end of the third week hypertension had been induced in all the animals receiving fructose. From the beginning of the fourth week to the end of the sixth week, one of those five groups (control) continued to receive only 10% (w/v) fructose solution, one group (standard) received ramipril (1 mg/kg/day, p.o.) plus 10% (w/v) fructose solution, and three groups (experimental) received CA at doses of 20, 30, and 40 mg/kg/day p.o., plus 10% (w/v) fructose solution. Blood pressure was measured weekly using a non-invasive blood pressure apparatus. After six weeks, the animals were sacrificed, and the anti-cataractogenic effects on the eye lenses were evaluated. Results: Administration of fructose elevated both the systolic and the diastolic blood pressures, which were significantly reduced by CA at all dose levels. In the control group, a significant increase in the malonaldehyde (MDA) level and decreases in the total protein, Ca2+adenosine triphosphate (ATP)ase activity, glutathione peroxidase, catalase, superoxide dismutase and glutathione levels, as compared to the normal group, were observed. Administration of CA at all doses significantly restored the enzymatic, non-enzymatic, antioxidants, total protein, and Ca2+ATPase levels, but decreased the MDA level, as compared to the control group. Conclusion: The present study revealed that CA modulated the antioxidant parameters of the serum and lens homogenates in hypertension-induced cataractogenic animals.

Estimating Population Density of Leopards in Semi-Arid habitat, Western India

Randeep Singh,Puneet Pandey,Qamar Qureshi,Kalyanasundaram Sankar,Paul R. Krausman,Surendra Prakash Goyal National Institute of Ecology 2023 국립생태원회보(PNIE) Vol.4 No.2

The leopard (Panthera pardus) is one of the most widespread felids worldwide. Despite their wide distribution, reliable data on leopard population densities are still inadequate for conservation and management strategies in different landscapes. In the present study, we estimated leopard density using camera traps in the Ranthambhore Tiger Reserve (RTR), Rajasthan, India, between December 2010 and February 2011, where leopards coexist alongside a high density of tigers (Panthera tigris), a larger predator (RTR). A sampling effort of 4,450 trap days was made from 178 camera trapping stations over 75 days, resulting in 46 suitable photo captures (25 right flanks and 21 left flanks). In total, 18 individuals (7 males, 8 females, and 3 unknown sexes) were identified using the right flanks, and the estimated leopard density was 8.8 (standard error=2.8) individuals/100 km². Leopard density appeared to respond to small prey (<50 kg weight) richness. As this is the first systematic study to provide baseline information on leopard density in RTR, it could form a baseline for comparison in future investigations.