Defence Bioengineering and Electromedical Laboratory

Bangalore, India

Defence Bioengineering and Electromedical Laboratory

Bangalore, India
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Makireddi S.,Hindustan Aeronautics Ltd | Varghese F.V.,Defence Bioengineering and Electromedical Laboratory | Balasubramaniam K.,Indian Institute of Technology Madras
Express Polymer Letters | Year: 2017

Graphene-polymer nanocomposite films show good piezoresistive behaviour and it is reported that the sensitivity increases either with the increased sheet resistance or decreased number density of the graphene fillers. A little is known about this behaviour near the percolation region. In this study, graphene nanoplatelet (GNP)/poly (methyl methacrylate) (PMMA) flexible films are fabricated via solution casting process at varying weight percent of GNP. Electrical and piezoresistive behaviour of these films is studied as a function of GNP concentration. Piezoresistive strain sensitivity of the films is measured by affixing the film to an aluminium specimen which is subjected to monotonic uniaxial tensile load. The change in resistance of the film with strain is monitored using a four probe. An electrical percolation threshold at 3 weight percent of GNP is observed. We report non-monotonic piezoresistive behaviour of these films as a function GNP concentration. We observe an increase in gauge factor (GF) with unstrained resistance of the films up to a critical resistance corresponding to percolation threshold. Beyond this limit the GF decreases with unstrained resistance. © BME-PT.

Rajendran R.,PSG College of Technology | Radhai R.,PSG College of Technology | Kotresh T.M.,Defence Bioengineering and Electromedical Laboratory | Csiszar E.,Budapest University of Technology and Economics
Carbohydrate Polymers | Year: 2013

In the present work ethanol, methanol, petroleum ether and water extracts of the leaves of Ocimum sanctum were screened for their anti-microbial activity by using the agar diffusion method. The minimum inhibitory concentration of the extracts was also measured. The methanol extracts O. sanctum proved to have the maximum antimicrobial effect were loaded inside the sodium alginate chitosan nanoparticles by cation induced controlled gelification method and finished on cotton fabric by pad dry cure method. The average particle size of the nanoparticles was calculated using dynamic light scattering technique. The antimicrobial activity of the fabrics was assessed by using the standard AATCC technique (AATCC 100). The quantitative tests proved that cotton fabrics finished with the methanol extract of O. sanctum loaded nanoparticles possessed remarkable antibacterial activities with excellent wash durability. The study revealed that the herb encapsulated nanoparticle could act as a biocontrol agent against bacteria in fabrics. © 2012 Elsevier Ltd.

PubMed | Shivaji University, Swami Ramanand Teerth Marathwada University, King Saud University, Defence Bioengineering and Electromedical Laboratory and Indian Defence Institute of Advanced Technology
Type: | Journal: Journal of colloid and interface science | Year: 2016

We report the rapid (superhydrophobic to superhydrophilic) transition property and improvement in the liquefied petroleum gas (LPG) sensing response of zinc oxide (ZnO) nanorods (NRs) on UV-irradiation and platinum (Pt) surface sensitization, respectively. The morphological evolution of ZnO NRs is evidenced from the field emission scanning electron microscope and atomic force microscope digital images and for the structural elucidation X-ray diffraction pattern is used. Elemental survey mapping is obtained from energy dispersive X-ray analysis spectrum. The optical properties have been studied by UV-Visible and photoluminescence spectroscopy measurements. The rapid (120sec) conversion of superhydrophobic (154) ZnO NRs film to superhydrophilic (7) is obtained under UV light illumination and the superhydrophobicity is regained by storing sample in dark. The mechanism for switching wettability behavior of ZnO NRs has thoroughly been discussed. In second phase, Pt-sensitized ZnO NRs film has demonstrated considerable gas sensitivity at 260ppm concentration of LPG. At 623K operating temperature, the maximum LPG response of 58% and the response time of 49sec for 1040ppm LPG concentration of Pt- sensitized ZnO NRs film are obtained. This higher LPG response of Pt-sensitized ZnO NRs film over pristine is primarily due to electronic effect and catalytic effect (spill-over effect) caused by an additional of Pt on ZnO NRs film surface.

Jayashankar B.,Defence Institute of Physiology and Allied science | Mishra K.P.,Defence Institute of Physiology and Allied science | Kumar M.S.Y.,Defence BioEngineering and Electromedical Laboratory | Udayasankar K.,Indian Central Food Technological Research Institute | And 3 more authors.
International Immunopharmacology | Year: 2012

In the present study, we have demonstrated the anti-inflammatory properties of supercritical CO 2 extract of seabuckthorn leaves (SCE) on mouse alveolar macrophage cell line (MH-S), human peripheral blood mononuclear cells (hPBMCs) in-vitro and in-vivo. Treatment of MH-S cells with SCE (0.5-100 μg/ml) significantly inhibited lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production. It also inhibited the release of LPS-induced pro-inflammatory cytokines IL-6 and TNF-α, which was further confirmed by suppression of LPS induced TNF-α in hPBMCs by ELISPOT assay. In addition, western blot analysis demonstrated that SCE decreased LPS-induced inducible nitric-oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in MH-S cells. Furthermore, SCE treatment also reduced nuclear factor-κB (NF-κB) translocation in nucleus induced by LPS in MH-S cells. To elucidate the molecular mechanism for inhibition of pro-inflammatory mediators by SCE (100 μg/ml), we further studied the effect of SCE on LPS-induced p38 mitogen-activated protein kinase (MAPK). It was observed that the phosphorylation of p38 MAPK in LPS-stimulated MH-S cells was significantly inhibited by SCE, which was further proven by suppression of LPS induced CD40 expression. The in-vivo model of AIA mice also showed a significant reduction in the inflammation of paw edema. These data collectively suggest that SCE suppressed the LPS-induced production of NO, IL-6, and TNF-α and expression of CD40, iNOS and COX-2 proteins by inhibiting NF-κB activation and phosphorylation of p38 MAPK. Hence, the SCE has potent anti-inflammatory activity and might be useful in chronic inflammatory diseases. © 2012 Elsevier B.V.

Sellamani M.,Bharathiar University | Kalagatur N.K.,Defence Food Research Laboratory | Siddaiah C.,University of Mysore | Mudili V.,Bharathiar University | And 4 more authors.
Frontiers in Microbiology | Year: 2016

The present study was aimed to evaluate the bio-control efficacy of Pediococcus pentosaceus isolated from traditional fermented dairy products originated from India, against the growth and zearalenone (ZEA) production of Fusarium graminearum. The cell-free supernatants of P. pentosaceus (PPCS) were prepared and chemical profiling was carried out by GC-MS and MALDI-TOF analysis. Chemical profiling of PPCS evidenced that, the presence of phenolic antioxidants, which are responsible for the antifungal activity. Another hand, MALDI-TOF analysis also indicated the presence of antimicrobial peptides. To know the antioxidant potential of PPCS, DPPH free radical scavenging assay was carried out and IC50 value was determined as 32 ± 1.89 μL/mL. The antifungal activity of P. pentosaceus was determined by dual culture overlay technique and zone of inhibition was recorded as 47 ± 2.81%, and antifungal activity of PPCS on F. graminearum was determined by micro-well dilution and scanning electron microscopic techniques. The minimum inhibitory concentration (MIC) of PPCS was determined as 66 ± 2.18 μL/mL in the present study. Also a clear variation in the micromorphology of mycelia treated with MIC value of PPCS compared to untreated control was documented. Further, the mechanism of growth inhibition was revealed by ergosterol analysis and determination of reactive oxygen species (ROS) in PPCS treated samples. The effects of PPCS on mycelial biomass and ZEA production were observed in a dose-dependent manner. The mechanism behind the suppression of ZEA production was studied by reverse transcriptase qPCR analysis of ZEA metabolic pathway genes (PKS4 and PKS13), and results showed that there is a dose dependent down-regulation of target gene expression in PPCS treated samples. The results of the present study were collectively proved that, the antifungal and ZEA inhibitory activity of PPCS against F. graminearum and it may find a potential application in agriculture and food industry as a natural bio-controlling agent. © 2016 Sellamani, Kalagatur, Siddaiah, Mudili, Krishna, Natarajan and Rao Putcha.

Jha V.N.,Defence Bioengineering and Electromedical Laboratory
Defence Science Journal | Year: 2012

Parajumping and sky diving in Armed Forces are used for rapid and strategic troop's deployments. In the combat free fall (CFF), the troops are paradropped from high altitudes in excess of 30,000 ft above mean sea level (AMSL) when they glide to a great distance, often within the enemy lines. Physiology of parajumping necessitates supplemental oxygen above 15,000 ft AMSL. Possibility of serious hypoxia and decompression sickness mandate the usage of supplemental oxygen through dedicated equipment. Other considerations such as effects of hypoxia on tissue oxygenation, physical and mental performance, neuronal functions, night vision, and prevailing anxiety factors, etc. also assume significance. Factors like intermittent hypoxic exposures, free fall, effects of posture during fall, and possible microgravity become mitigating factors. Owing to limited oxygen supply being carried by the paratroopers, using dilution method in providing the breathing gas too assumes importance at times as a trade-off between requirements and supply. This paper reviews the literatures to extent possible and recommends certain concepts for an optimal oxygen usage during the high altitude parajumps. © 2012, DESIDOC.

Selvakumar D.,Defence Bioengineering and Electromedical Laboratory | Selvakumar D.,Bharathiar University | Dharmaraj N.,Bharathiar University | Kadirvelu K.,Bharathiar University | And 2 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Indium(III) hydroxide (In(OH)3) powders prepared via Triton X-100 mediated hydrothermal method was sintered at different temperatures (400, 500 and 600 °C) to yield indium(III) oxide nanoparticles (In 2O3 NPs). Thermal studies of In(OH)3 confirmed complete conversion to In2O3 around 400 °C. Powder X-ray diffraction (XRD) pattern of sintered In2O3 nanoparticles revealed the formation of phase pure cubic In2O 3. The crystallite size of In2O3 NPs was increased from 12 to 26 nm upon increasing the sintering temperature from 400 °C to 600 °C, while the percentage crystallinity was increased up to 90% after sintering at 600 °C. A red shift in the band gap energy was observed with increasing sintering temperature due to the larger size of sintered In 2O3 NPs. Room temperature photoluminescence spectra of the indium oxide nanoparticles showed both near band and excitonic emission of In2O3 due to oxygen vacancies. © 2014 Published by Elsevier B.V.

Dhanasingh S.,Defence BioEngineering and Electromedical Laboratory | Nallaperumal S.K.,Defence BioEngineering and Electromedical Laboratory
World Academy of Science, Engineering and Technology | Year: 2010

Microparticles carrier systems made from naturally occurring polymers based on chitosan/casein system appears to be a promising carrier for the sustained release of orally and parenteral administered drugs. In the current study we followed a microencapsulation technique based aqueous coacervation method to prepare chitosan/casein microparticles of compositions 1:1, 1:2 and 1:5 incorporated with chloramphenicol. Glutaraldehyde was used as a chemical cross-linking agent. The microparticles were prepared by aerosol method and studied by optical microscopy, infrared spectroscopy, thermo gravimetric analysis, swelling studies and drug release studies at various pH. The percentage swelling of the polymers are found to be in the order pH 4 > pH 10 > pH 7 and the increase in casein composition decrease the swelling percentage. The drug release studies also follow the above order.

Selvakumar D.,Defence Bioengineering and Electromedical Laboratory | Rajeshkumar P.,Defence Bioengineering and Electromedical Laboratory | Dharmaraj N.,Bharathiar University | Kumar N.S.,Defence Bioengineering and Electromedical Laboratory
Materials Today: Proceedings | Year: 2016

Gas sensors were fabricated using nanostructured indium oxide (In2O3) and platinum doped indium oxide (Pt-In2O3) prepared by surfactant assisted hydrothermal method. The optimum working temperature of the sensors was around 165 °C, which is lower than the literature reports. The sensor fabricated using Pt-In2O3 exhibited higher response as compared to undopedIn2O3.Their gas sensing properties investigated with NO2 gaswith2.5 and 5 ppmrevealed that the sensors showed a concentration dependent electrical resistance. © 2016 Elsevier Ltd.

Bhargavi R.,Defence Bioengineering and Electromedical Laboratory | Kadirvelu K.,Bharathiar University | Kumar N.S.,Defence Bioengineering and Electromedical Laboratory
AIP Conference Proceedings | Year: 2013

The objective of this work is to evaluate spherical carbon and modified spherical carbon for the removal of phenol from aqueous solution in static and dynamic studies under various conditions. It explores mainly two adsorbents, that is, activated spherical carbon (ASC) and modified activated spherical carbon (SSC). SEM characterization of both the adsorbents showed a clear change in the physical and chemical properties of the modified adsorbent from its precursor activated carbon. Both the adsorbents are subjected to static mode adsorption studies and after a comparison based on isotherm analysis; more efficient adsorbent is screened for column mode adsorption studies. The phenol removal increased for modified carbon. The aim of carrying out column mode studies will aid in ascertaining the practical applicability of the adsorbent in the real system and therefore, to assess the effect of various process variables, viz., bed height of the adsorbent, flow rate and initial concentration of the adsorbate on breakthrough time and adsorption capacity. The column studies generated data were modeled using the empirical relationship based on Bohart-Adams model. At the end, the option of regenerating the adsorbent was also explored using sodium hydroxide with the aim of minimize the hazardous generated and also to reuse the adsorbent material for many cycles without affecting original properties. Adsorbent regeneration efficiency of 72% was achieved. This investigation reveals that the material used as an adsorbent is very effective with high adsorption capacities and also possible to use in the real contaminated system. © 2013 AIP Publishing LLC.

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