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Investigations on the nonlinear optical properties of glycinium oxalate single crystals

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Optoelectronics Letters 2011年第2期7卷 136-138页

作者： arun. k. J S. Jayalekshmi Division for Research in Advanced Materials Department of Physics Cochin University of Science and Technology

Single crystals of glycinium oxalate (GLO) are grown by solution growth technique. The Z scan technique is used to elucidate the third order nonlinearity in the material. The results indicate that the compound exhibits reverse saturable absorption (RSA) and self-defocusing performance. The second harmonic generation (SHG) efficiency of the crystal evaluated by kurtz and Perry technique is compared with that of the standard kDP crystal. Attempt is made to correlate the SHG efficiency with the crystalline perfection in the material.

关键词：非线性光学性能单晶生长技术草酸三阶非线性光学特性 kDP晶体二次谐波产生倍频效率反饱和吸收

Comparative cytotoxicity of nanoparticles and ions to Escherichia coli in binary mixtures

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Journal of Environmental Sciences 2017年第5期29卷 11-19页

作者： Swati Srivastaua arun kumar Department of Civil Engineering Indian Institute of Technology Delhi New Delhi 110016 India

The objective of this study was to understand toxicity of mixture of nanoparticles （NPs）（ZnO and TiO2） and their ions to Escherichia coll. Results indicated the decrease in percentage growth of E. coli with the increase in concentration of NPs both in single and mixture setups. Even a small concentration of I mg/L was observed to be significantly toxic to E. coli in binary mixture setup （exposure concentration： 1 mg/L ZnO and 1 mg/L TiO2; 21.15% decrease in plate count concentration with respect to control）. Exposure ofE. coli to mixture of NPs at 1000 mg/L （i.e., 1000 mg/L ZnO and 1000 mg/L TiO2） resulted in 99.63% decrease in plate count concentration with respect to control. Toxic effects of ions to E. coli were found to be lesser than their corresponding NPs. The percentage growth reduction was found to be 36% for binary mixture of zinc and titanium ions at the highest concentration （i.e., 803.0 mg/L Zn and 593.3 mg/L Ti where ion concentrations are equal to the Zn ions present in 1000 mg/L ZnO NP solution and Ti＋4 ions present in 1000 mg/L TiO2 NP solution）. Nature of mixture toxicity of the two NPs to E. coli was found to be antagonistic. The alkaline phosphatase （Alp） assay indicated that the maximum damage was observed when E. coli was exposed to 1000 mg/L of mixture of NPs. This study tries to fill the knowledge gap on information of toxicity of mixture of NPs to bacteria which has not been reported earlier.

关键词： E. coli Zinc oxide nanoparticles Titanium dioxide nanoparticles Mixture toxicity Alkaline phosphatase assay

Fragment emission and critical behavior in light and heavy charged systems

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Chinese Physics C 2021年第1期45卷 215-225页

作者： Samiksha Sood Rohit kumar arun Sharma Sakshi Gautam Rajeev k.Puri Department of Physics Panjab UniversityChandigarh 160014India Department of Physics G.D.College.BillawarJammu 185204India

We study the emission of fragments in central collisions of light and heavily charged systems of^4+Ar+^45 Sc and^s4kr+^197 Au,respectively,using the Quantum Molecular Dynamics(QMD)model as the primary *** fragments are identified using an energy based clusterization algorithm,i.e.,the Simulated Annealing Clusterization Algorithm(SACA).The charge distributions of intermediate mass fragments[3≤Zf≤12]are fitted with power-law(∝Zf^-τ)and exp on ential(∝e^-λZf)fits in order to extract the parametersτandλ,whose minimum values are also sometimes linked with the onset of fragmentation or the critical point for a liquid-gas phase *** parameters such as the normalized second moment,,average size of the second largest cluster,phase separation parameter(Sp),bimodal parameter(P),information entropy(H),and Zipfs law are also analyzed to find the exact energy of the onset of *** detailed analysis predicts that an energy point exists between 20-23.1 MeV/nucleon,which is very close to the experimentally observed value of 23.9 MeV/nucleon for the^40Ar+^45Sc *** also find that the critical energy deduced using Zipfs law is higher than those predicted from other critical ***,no minimum is found for t values of the highly charged system of^84kr+^197Au,in agreement with experimental findings and various theoretical *** observe that the QMD+SACA model calculations are in agreement with the experimental *** agreement supports our results regarding the energy point of the liquid-gas phase transition and the onset of fragmentation.

关键词： heavy-ion collisions transport model clusterization algorithm Monte-Carlo technique li・quid-gas phase transition

Single incision laparoscopic surgery

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World Journal of Gastroenterology 2010年第21期16卷 2705-2706页

作者： arun Prasad Department of Minimal Access Surgery Apollo HospitalNew Delhi 110044India

As a complement to standard laparoscopic surgery and a safe alternative to natural orifice transluminal endoscopic surgery,single incision laparoscopic surgery is gaining *** are expensive ports,disposable hand instruments and flexible endoscopes that have been suggested to do this surgery and would increase the cost of *** a simple surgery like laparoscopic cholecystectomy,these extras are not needed and the surgery can be performed using standard ports,instruments and *** port insertion and use of instruments by the "chop stick method" are recommended to successfully do the procedure as we have done in our so far small series of 40 cases.

关键词： Single incision laparoscopic surgery Cholecystectomy

Design,molecular docking,synthesis,characterization,biologi- cal activity evaluation (against MES model),in-silico biological activity spectrum (PASS analysis),toxicological and predicted oral rat LDso studies of novel sulphonamide derivatives

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Frontiers in Biology 2018年第6期13卷 425-451页

作者： Ajeet Arvind kumar arun k.Mishra Drug Design Laboratory School of Pharmaceutical SciencesIFTM UniversityMoradabadUttar Pradeshlndia Department of Pharmaceutical Chemistry S.D.College of Pharmacy and Vocational StudiesMuzaffarnagarUttar PradeshIndia

Among the reported potential agents to treat the epilepsy, sulphonamides are important and their significance cannot be ignored. A series of substituted 4-amino-benzene sulfonamides were designed, keeping in view the structural requirement of pharmacophore. Lipinski rule of five has been calculated; failure to Lipinski rule was not observed. Docking was performed through AutoDock Vina. Molecules have been screened out through docking. Compounds were synthesized and characterized through IR, 1HNMR, 13C NMR, Mass and elemental analysis. The anticonvulsant activity of the synthesized compounds was assessed using the Maximal Electroshock Seizure (MES) model. In-silico biological activity spectrum, toxicological studies, predicted oral rats LD50 were performed. Docking studies showed good interaction with lyase (Oxo-acid) - human carbonic anhydrase-I (1AZM). The in-silico studies proved them to be with good drug-likeness properties, especially 4-(3-Acetyl-phenylamino)-methyl)-benzenesulfonamide (2g). These results revealed that the synthesized compounds (1a-1c, 2a-2q) exhibited promising anticonvulsant effect against MES model for inhibition of Lyase- Human Carbonic Anhydrase-I. After investigating all the results, the compound 4-(3-Acetyl-phenylamino)-methyl)-benzenesulfonamide (2g) is found to be best in the series. A comparatively good activity of compound 2g suggests us that sulphonamide can be leads to further optimization for building potent and chemically diversified anti-convulsant agents.

关键词： anticonvulsant sulfonamide docking in-silico studies

Relating Maxwell's demon and quantitative analysis of information leakage for practical imperative programs

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Chinese Physics B 2017年第10期26卷 122-131页

作者： kushal Anjaria arun Mishra Department of Computer Science & Engineering DIAT

Shannon observed the relation between information entropy and Maxwell demon experiment to come up with information entropy formula. After that, Shannon＇s entropy formula is widely used to measure information leakage in imperative programs. But in the present work, our aim is to go in a reverse direction and try to find possible Maxwell＇s demon experimental setup for contemporary practical imperative programs in which variations of Shannon＇s entropy formula has been applied to measure the information leakage. To establish the relation between the second principle of thermodynamics and quantitative analysis of information leakage, present work models contemporary variations of imperative programs in terms of Maxwell＇s demon experimental setup. In the present work five contemporary variations of imperative program related to information quantification are identified. They are：（i） information leakage in imperative program, （ii） imperative multi- threaded program, （iii） point to point leakage in the imperative program, （iv） imperative program with infinite observation, and （v） imperative program in the SOA-based environment. For these variations, minimal work required by an attacker to gain the secret is also calculated using historical Maxwell＇s demon experiment. To model the experimental setup of Maxwell＇s demon, non-interference security policy is used. In the present work, imperative programs with one-bit secret information have been considered to avoid the complexity. The findings of the present work from the history of physics can be utilized in many areas related to information flow of physical computing, nano-computing, quantum computing, biological computing, energy dissipation in computing, and computing power analysis.

关键词： information Maxwell's demon second principle of thermodynamics information security reversible system

Securing 3D Point and Mesh Fog Data Using Novel Chaotic Cat Map

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Computers, Materials & Continua 2023年第3期74卷 6703-6717页

作者： k.Priyadarsini arun kumar Sivaraman Abdul Quadir Md Areej Malibari Department of Data Science and Business Systems School of ComputingCollege of Engineering and TechnologySRM Institute of Science and TechnologyKattankulathurChennai603203India School of Computer Science and Engineering Vellore Institute of TechnologyChennai600127India Department of Industrial and Systems Engineering College of EngineeringPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia

With the rapid evolution of Internet technology,fog computing has taken a major role in managing large amounts of *** major concerns in this domain are security and ***,attaining a reliable level of confidentiality in the fog computing environment is a pivotal *** different types of data stored in the fog,the 3D point and mesh fog data are increasingly popular in recent days,due to the growth of 3D modelling and 3D printing ***,in this research,we propose a novel scheme for preserving the privacy of 3D point and mesh fog *** Cat mapbased data encryption is a recently trending research area due to its unique properties like pseudo-randomness,deterministic nature,sensitivity to initial conditions,ergodicity,*** boost encryption efficiency significantly,in this work,we propose a novel Chaotic Cat *** sequence generated by this map is used to transform the coordinates of the fog *** improved range of the proposed map is depicted using bifurcation *** quality of the proposed Chaotic Cat map is also analyzed using metrics like Lyapunov exponent and approximate *** also demonstrate the performance of the proposed encryption framework using attacks like brute-force attack and statistical *** experimental results clearly depict that the proposed framework produces the best results compared to the previous works in the literature.

关键词： Chaotic cat map fog computing encryption 3D point fog 3D mesh

Structural and luminescence enhancement properties of Eu^(3+)/Ag nanocrystallites doped SiO_2-TiO_2 matrices

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Journal of Rare Earths 2013年第5期31卷 441-448页

作者： arun kumar k V Revathy k P Prathibha Vasudevan Sunil Thomas Biju P R Unnikrishnan N V School of Pure & Applied Physics Mahatma Gandhi University

We reported here the structural and optical characterisation of silver nanocrystallites/Eu3＋：SiO2-TiO2 matrices synthesised through sol-gel route. Structural characterisations were done by using energy dispersive spectroscopy （EDX）, X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR）, atomic force microscope （AFM） and transmission electron microscopy （TEM） measurements and optical characterisations were performed by absorption and emission spectroscopy. The TEM and XRD measurements confirmed the presence of nanocrystals. A broad absorption band was observed due to surface plasmon resonance of silver nanocrystals. The effect of silver nanocrystals on the emission spectrum of Eu3＋ doped SiO2-TiO2 matrices was discussed. An attempt was made to explain this fluorescence enhancement by invoking phenomena such as energy transfer, asymmetry ratio, surface plasmon, surface roughness, crystallinity and grain boundary. Our analysis, based on the experimental results, suggested that all the phenomena except crystallinity and grain boundary had favourable effects on fluorescence enhancement. We also estimated the relevant parameters associated with the phenomena that affected the fluorescence emission from the Eu3＋ ions in the matrix. It was seen that the theoretical estimate of fluorescence enhancement agreed well with the experimental estimate.

关键词： sol-gel luminescence SiO2-TiO2 silver nanoparticles rare earths

Shock wave mitigation using zig-zag structures and cylindrical obstructions

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Defence Technology（防务技术） 2021年第6期17卷 1840-1851页

作者： arun kumar R Vaibhav Pathak Department of Mechanical Engineering Indian Institute of Technology Jodhpur(IITJ)JodhpurRajasthan342037India

The present study focuses on the mitigation of shock wave using novel geometric passages in the flow *** strategy is to produce multiple shock reflections and diffractions in the passage with minimum flow obstruction,which in turn is expected to reduce the shock wave strength at the target *** the present study the interaction of a plane shock front(generated from a shock tube)with various geometric designs such as,1)zig-zag geometric passage,2)staggered cylindrical obstructions and 3)zigzag passage with cylindrical obstructions have been investigated using computational *** is seen from the numerical simulation that,among the various designs,the maximum shock attenuation is produced by the zig-zag passage with cylindrical obstructions which is then followed by zig-zag passage and staggered cylindrical obstructions.A comprehensive investigation on the shock wave reflection and diffraction phenomena happening in the proposed complex passages have also been carried *** the new zig-zag design,the initial shock wave undergoes shock wave reflection and diffraction process which swaps alternatively as the shock front moves from one turn to the other *** cyclic shock reflection and diffraction process helps in diffusing the shock wave energy with practically no obstruction to the flow *** is found that by combining the shock attenuation ability of zig-zag passage(using shock reflection and diffraction)with the shock attenuation ability of cylindrical blocks(by flow obstruction),a drastic attenuation in shock strength can be achieved with moderate level of flow blocking.

关键词： Blast wave mitigation Blockage ratio Geometric obstructions Shock wave reflection and diffraction Zig-zag structure