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Conducting polymer PEDOT:PSS coated Co_(3)O_(4) nanoparticles as the anode for sodium-ion battery applications

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Frontiers of Materials Science 2022年第2期16卷 143-152页

作者： Kevin VARGHESE Dona Susan BAJI Shantikumar Nair Dhamodaran SANTHANAGOPALAN Centre for Nanosciences Amrita Vishwa VidyapeethamPonekkaraKochi 682041India

Metal oxides are considered as potential anodes for sodium-ion batteries(SIBs).Nevertheless,they suffer from poor cycling and rate capability.Here,we investigate conductive polymer coating on Co_(3)O_(4)nanoparticles varying with different percentages.X-ray diffraction,electron microscopy and surface chemical analysis were adopted to analyze coated and uncoated Co_(3)O_(4)nanoparticles.Conducting polymer,poly(3,4-ethylene dioxythiophene)polystyrene sulfonate(PEDOT:PSS),has been utilized for coating.Improved specific capacity and rate capability for an optimal coating of 0.5 wt.%were observed.The 0.5 wt.%coated sample outperformed the uncoated one in terms of capacity,rate capability and coulombic efficiency.It delivered a reversible capacity of 561 mAh·g^(−1)at 100 mA·g^(−1)and maintained a capacity of 318 mAh·g^(−1)at a high rate of 1 A·g^(−1).Increasing the PEDOT:PSS coating percentage led to lower performance due to the thicker coating induced kinetic issues.Ex-situ analysis of the 0.5 wt.%coated sample after 100 cycles at 1 A·g^(−1)was characterized for performance correlation.Such a simple,cost-effective and wet-chemical approach has not been employed before for Co_(3)O_(4)as the SIB anode.

关键词： Co_(3)O_(4) sodium-ion battery anode conducting polymer surface coating

A New Regularization Method for a Parameter Identification Problem in a Non-linear Partial Differential Equation

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Journal of Partial Differential Equations 2023年第2期36卷 147-190页

作者： Nair M.Thamban ROY Samprita Das Department of Mathematics BITS PilaniK K Birla Goa CampusZuarinagerGoa 403726India Department of Mathematics and Statistics IISER KokotaNadiaWest Bengal 741246India

We consider a parameter identification problem associated with a quasilinear elliptic Neumann boundary value problem involving a parameter function a(-)and the solution u(-),where the problem is to identify a(-)on an interval I:=g(F)from the knowledge of the solution u()as g on I,where F is a given curve on the boundary of the domain CR^(3) of the problem and g is a continuous function.The inverse problem is formulated as a problem of solving an operator equation involving a compact operator depending on the data,and for obtaining stable approximate solutions under noisy data,a new regularization method is considered.The derived error estimates are similar to,and in certain cases better than,the classical Tikhonov regularization considered in the literature in recent past.

关键词： Ill-posed regularization parameter identification

Green synthesis,characterization and antimicrobial activity of silver nanoparticles using methanolic root extracts of Diospyros sylvatica

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Journal of Environmental Sciences 2017年第5期29卷 157-163页

作者： lakshmi Pethakamsetty Kalyani Kothapenta Hanumanta Rao Nammi lakshmi Kalyani Ruddaraju Pratap Kollu Soon Gil Yoon Sri Venkata Narayana Pammi Department of Microbiology College of Science and Technology Andhra University Visakhapatnam 530003 India DST-PURSE Programme Advanced Analytical Laboratory Andhra University Visakhapatnam 530003 India Sri Vishnu College of Pharmacy Department of Pharmaceutical Technology Vishnupur Bhimavaram A.P. 530041 India DST-INSPIRE Faculty Department of Metallurgical Engineering & Materials Science Indian Institute of Technology Bombay Mumbai 400076 India Department of Materials Science and Engineering Chungnam National University Daeduk Science Town 305-764 Daejeon South Korea

The current research study focuses to formulate the biosynthesized silver nanoparticles for the first time from silver acetate using methanolic root extracts of Diospyros sylvatica,a member of family Ebenaceae. TEM analysis revealed the average diameter of Ag NPs around 8 nm which is in good agreement with the average crystallite size（10 nm）calculated from X-ray Diffraction（XRD）analysis. Further the study has been extended to the antimicrobial activity against test pathogenic Gram（＋）ve,Gram（-）ve bacterial and fungal strains. The bioinspired Ag-NP showed promising activity against all the tested bacterial strains and the activity was enhanced with increased dosage levels

关键词： Root extract Silver nanoparticles Antimicrobial properties

Process optimization for microencapsulation of probiotic yeasts

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Frontiers in Biology 2018年第3期13卷 197-207页

作者： Mangala Lakshmi Ragavan Nilanjana Das School of Bioscienees and Technology Vellore Institute of Technology Vellore Tamil Nadu India

Microencapsulation is a technique which improves the survival and viability of probiotics. We demonstrate encapsulation of five potential probiotic yeasts with alginate and gum as encapsulation matrices to improve their gastrointestinal transit. Gum extracted from various cereals viz. rice, oats, barley, finger millet and pearl millet along with alginate have been used to encapsulate five potential probiotic yeasts. Screening was carried out by measuring swelling index, encapsulation efficiency and nutritional value of microcapsules encapsulated with alginate and gum. The concentration of OBG, sodium alginate and inoculum dosage of probiotic yeasts was optimized using response surface methodology (RSM). Efficiency of alginate OBG microcapsules with or without coating materials viz. whey protein and chitosan also tested. The mucoadhesion ability and storage stability of alginate OBG microcapsules with coating materials were tested. Highest encapsulation efficiency of probiotic yeasts was noted using oats bran gum (OBG) microcapsules along with alginate in all the five probiotic yeasts. Notably whey protein coated microcapsules showed maximum GIT tolerance (95%) and mucoadhesion (90%) for L. starkeyi VIT-MN03. The minimum loss of viability was observed in L. starkeyi VITMN03 microcapsules on 60th day of storage. This is the first report on optimization and survival of microencapsulated probiotic yeasts under simulated GIT conditions using natural gum and alginate as encapsulation matrices and whey protein as coating material.

关键词： microencapsulation, oats bran gum （OBG）, probiotic yeast, response surface methodology, simulated GIT condition, whey protein

A combination of learning and non-learning based method for enhancement, compression and reconstruction of underwater images

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Aquaculture and Fisheries 2022年第2期7卷 201-210页

作者： Rashmi S.Nair Sandanam Domnic Department of Computer Applications National Institute of TechnologyTiruchirappalliTamil Nadu620015India

Complex nature of underwater environment poses biggest challenge towards image acquisition and transmission of underwater images.This paper proposes an integrated approach which consists of a non-learning enhancement method with deep Convolutional Neural Networks(CNN)for compression and reconstruction of the image.The proposed method does color and contrast correction for image enhancement.The enhanced images are down-sampled using 9-layer CNN followed by Discrete Wavelet Transform(DWT).The decompression is done by using Inverse DWT.Further,the sub-pixel up-sampled image is de-blurred using a three-layer CNN.Residual Dense CNN(RD-CNN)is used to improve the quality of the reconstructed image after deblurring.The quality of the reconstructed images is measured using Peak Signal to Noise Ratio(PSNR)and Structural Similarity Index Metric(SSIM).The proposed model provides better image enhancement,compression,and reconstruction quality than the existing state-of-the-art methods and Super Resolution CNN(SRCNN)respectively.

关键词： Convolutional neural network Discrete wavelet transform Residual dense convolutional neural network Peak signal to noise ratio Structural similarity index metric Super resolution CNN

Investigation and statistical modeling of InAs-based double gate tunnel FETs for RF performance enhancement

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Journal of Semiconductors 2018年第5期39卷 30-40页

作者： S.Poorvasha B.lakshmi School of Electronics Engineering VIT University

In this paper,RF performance analysis of In As-based double gate（DG）tunnel field effect transistors（TFETs）is investigated in both qualitative and quantitative fashion.This investigation is carried out by varying the geometrical and doping parameters of TFETs to extract various RF parameters,unity gain cut-off frequency（f_t）,maximum oscillation frequency（f_（max））,intrinsic gain and admittance（Y）parameters.An asymmetric gate oxide is introduced in the gate-drain overlap and compared with that of DG TFETs.Higher ON-current（ION）of about 0.2 mA and less leakage current（IOFF）of 29 f A is achieved for DG TFET with gate-drain overlap.Due to increase in transconductance（g_m）,higher ft and intrinsic gain is attained for DG TFET with gate-drain overlap.Higher f_（max） of 985 GHz is obtained for drain doping of 5×10^（17）cm^（-3） because of the reduced gate-drain capacitance（C_（gd））with DG TFET with gate-drain overlap.In terms of Y-parameters,gate oxide thickness variation offers better performance due to the reduced values of Cgd.A second order numerical polynomial model is generated for all the RF responses as a function of geometrical and doping parameters.The simulation results are compared with this numerical model where the predicted values match with the simulated values.

关键词： double gate tunnel FETs gate-drain overlap unity gain cut-off frequency maximum oscillation frequency Y-parameters modeling

Anti-angiogenic agents in metastatic colorectal cancer

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World Journal of Gastrointestinal Oncology 2015年第7期7卷 71-86页

作者： Bhavana Konda Helen Shum lakshmi Rajdev Department of Medical Oncology Albert Einstein College of Medicine/Montefiore Medical Center

Colorectal cancer(CRC) is a major public health concern being the third leading cause of cancer mortality in the United States. The availability of better therapeutic options has led to a decline in cancer mortality in these patients. Surgical resection should be considered in all stages of the disease. The use of conversion therapy has made surgery a potentially curative option even in patients with initially unresectable metastatic disease. In this review we discuss the role of various antiangiogenic agents in patients with metastatic CRC(m CRC). We describe the mechanism of action of these agents, and the rationale for their use in combination with chemotherapy. We also review important clinical studies that have evaluated the safety and efficacy of these agents in m CRC patients. Despite the discovery of several promising anti-angiogenic agents, m CRC remains an incurable disease with a median overall survival of just over 2 years in patients exposed to all available treatment regimens. Further insights into tumor biology and tumor microenvironment may help improve outcomes in these patients.

关键词： Anti-angiogenic agents Metastatic colorectalcancer Targeted agents Conversion therapy Colorectalmetastasectomy

WO_(3) passivation layer-coated nanostructured TiO_(2): An efficient defect engineered photoelectrode for dye sensitized solar cell

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Journal of Semiconductors 2021年第5期42卷 91-98页

作者： Arya Babu Arya Vasanth Shantikumar Nair Mariyappan Shanmugam Amrita Centre for Nanosciences and Molecular Medicine Amrita Vishwa VidyapeethamKochiKerala-682041India

Major loss factors for photo-generated electrons due to the presence of surface defects in titanium dioxide(Ti O_2)were controlled by RF-sputtered tungsten trioxide(WO_3) passivation. X-ray photoelectron spectroscopy assured the coating of WO3 on the Ti O_2 nanoparticle layer by showing Ti 2 p, W 4 f and O 1 s characteristic peaks and were further confirmed by X-ray diffraction studies. The coating of WO_3 on the Ti O_2 nanoparticle layer did not affect dye adsorption significantly. Dye sensitized solar cells(DSSCs) fabricated using WO_3-coated Ti O_2 showed an enhancement of ~10% compared to DSSCs fabricated using pristine Ti O_2-based photo-electrodes. It is attributed to the WO_3 passivation on Ti O_2 that creates an energy barrier which favored photo-electron injection by tunneling but blocked reverse electron recombination pathways towards holes available in highest occupied molecular orbital of the dye molecules. It was further evidenced that there is an optimum thickness(duration of coating) of WO_3 to improve the DSSC performance and longer duration of WO_3 suppressed photo-electron injection from dye to Ti O_2 as inferred from the detrimental effect in short circuit current density values. RF-sputtering yields pinhole-free,highly uniform and conformal coating of WO_3 onto any area of interest, which can be considered for an effective surface passivation for nanostructured photovoltaic devices.

关键词： charge transport recombination tungsten oxide solar cell interface defects

Biofilm-forming fluconazole-resistant Candida auris causing vulvovaginal candidiasis in an immunocompetent patient: A case report

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Asian Pacific Journal of Tropical Medicine 2021年第2期14卷 94-96页

作者： lakshmi Krishnasamy Jayasankari Senthilganesh Chitralekha Saikumar Paramasivam Nithyanand Department of Microbiology Sree Balaji Medical College and HospitalChennai-600044Bharath Institute of Higher Education and ResearchIndia Biofilm Biology Laboratory Centre for Research on Infectious Diseases(CRID)School of Chemical and BiotechnologySASTRA Deemed UniversityTirumalaisamudramThanjavur 613401Tamil NaduIndia

Rationale:Candida auris is a potential emerging pathogen among Candida and causes serious health threats globally.Patient concerns:We reported a case of vulvovaginal candidiasis caused by Candida auris.A 26-year-old female presented with complaints of vaginal discharge,itching and low back pain.Diagnosis:High vaginal swab culture yielded Candida.The strain was confirmed as Candida auris by amplification and sequencing the internal transcribed spacer region.Antifungal susceptibility testing revealed that the isolate was resistant to fluconazole,amphotericin B and clotrimazole and susceptible to ketoconazole and nystatin.The isolate also exhibited biofilm forming ability.Interventions:Her symptoms did not subside with initial management with fluconazole and clotrimazole.Later,she was started on ketoconazole therapy.The patient responded well to ketoconazole.Outcome and lessons:To the best of our knowledge,this is the first report about the presence of a drug resistant biofilm forming Candida auris strain isolated from a vaginal swab sample from Chennai area.Biofilm forming ability might contribute to its drug resistance.Nucleic acid analysis helps in rapid and accurate identification of such rare species.

关键词： Candida auris Resistance Biofilm Scanning electron microscopy