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Opportunities and challenges for developing closed-loop bioelectronic medicines

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Neural Regeneration Research 2019年第1期14卷 46-50页

作者： Patrick d.Ganzer gaurav Sharma Medical devices and Neuromodulation Battelle Memorial Institute

The peripheral nervous system plays a major role in the maintenance of our physiology. Several peripheral nerves intimately regulate the state of the brain, spinal cord, and visceral systems. A new class of therapeutics, called bioelectronic medicines, are being developed to precisely regulate physiology and treat dysfunction using peripheral nerve stimulation. In this review, we first discuss new work using closed-loop bioelectronic medicine to treat upper limb paralysis. In contrast to open-loop bioelectronic medicines, closed-loop approaches trigger ‘on demand' peripheral nerve stimulation due to a change in function(e.g., during an upper limb movement or a change in cardiopulmonary state). We also outline our perspective on timing rules for closedloop bioelectronic stimulation, interface features for non-invasively stimulating peripheral nerves, and machine learning algorithms to recognize disease events for closed-loop stimulation control. Although there will be several challenges for this emerging field, we look forward to future bioelectronic medicines that can autonomously sense changes in the body, to provide closed-loop peripheral nerve stimulation and treat disease.

关键词： spinal cord injury stroke plasticity closed-loop bioelectronic medicine machine learning nerve stimulation vagus nerve

Reliability assessment of deep excavations in spatially random cohesion weakening friction strengthening massive rocks:Application to nuclear repositories

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Underground Space 2023年第6期13卷 48-73页

作者： Akshay Kumar gaurav Tiwari department of Civil Engineering Indian Institute of Technology KanpurKanpurUttar Pradesh 208016India

An augmented methodology is developed to estimate the reliability of deep excavations along spatially variable massive rock masses using the cohesion weakening friction strengthening(CWFS)*** parameters of the CWFS model were initially identified using Sobol’s global sensitivity analysis based on their influence on the displacements and excavation damage zone around *** probability of failure was estimated by performing Mont–Carlo Simulations on random finite difference models of excavations generated via MATLAB-FLAC2d coupling,considering the spatial variation of these sensitive *** variation was modeled by generating anisotropic random fields of sensitive CWFS parameters via the recently developed Fourier series method and updated correlations suggested by Walton(2019).The proposed methodology was demonstrated for a proposed deep nuclear waste repository to be located in *** from the developed methodology were systematically compared with those of traditional reliability(ignoring spatial variation)and deterministic methods(ignoring uncertainty).Although the developed methodology was computationally complex,it was judged to be the most realistic due to the realistic consideration of heterogeneous distributions of rock *** methodologies underestimate/overestimate the excavation performance due to negligence of uncertainty and spatial ***,a parametric analysis was performed using developed methodology by varying the initial friction angle,scale of fluctuations(SOFs)and dilation *** effect of initial friction angle was observed to be more pronounced on the probability of failures as compared to SOFs and dilation *** observations were made related to the excavation damage zone(EdZ)development quantified using yield area ratio.

关键词： deep excavations Brittle failures CWFS model Sobol’s sensitivity Moving least square response surface Fourier series random field

Piezoelectric material selection for transducers under fuzzy environment

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Journal of Advanced Ceramics 2013年第2期2卷 141-148页

作者： gaurav VATS Rahul VAISH School of Engineering Indian Institute of Technology MandiHimachal Pradesh 175001India

Piezoelectric ceramics are extensively investigated materials for transducer *** selection of optimal piezoelectric material for this particular application is a tedious *** depends upon various physical properties,including piezoelectric charge coefficient(d33),electromechanical coupling factor(K_(p)),dielectric constant(ε_(r)),and dielectric loss(tanδ).The classical multiple attribute decision making(MAdM)can be used for decision making if these properties are known ***,these properties cannot be expressed by exact numerical values,since they are dependent upon the microstructure and fabrication ***-based MAdM approaches can be helpful in such *** this paper,we have determined the ranks and rank indices(for degree of closeness)of important piezoelectric materials using fuzzy VlseKriterijumska Optimisacija I Kompromisno Resenje(VIKOR)***(8/65/35)((Pb_(1-x)La_(x))(Zr_(y)Ti_(1-y))O_(3))and KNN-LT-LS((K_(0.44)Na_(0.52)Li_(0.04))-(Nb0_(.84)Ta_(0.10)Sb_(0.06))O_(3))consecutively are found to be the top-rank piezoelectric *** indicates that KNN-LT-LS can be used on behalf of lead-based piezo-ceramics.

关键词： piezoceramics selection MAdM fuzzy approach transducer application

Automated location correction and spot height generation for named summits in the coterminous United States

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International Journal of digital Earth 2020年第12期13卷 1570-1584页

作者： Samantha T.Arundel gaurav Sinha U.S.Geological Survey Center of Excellence for Geospatial Information ScienceRollaMOUSA department of Geography Ohio UniversityAthensOHUSA

Spot elevations published on historical *** Survey topographic maps were established as needed to enhance information imparted by the quadrangle’s *** addition to other features,labels were routinely placed on mountain *** some elevations were established through field survey triangulation,many were computed during photogrammetric ***,Global Navigation Satellite System(GNSS)receivers have replaced expensive triangulation ***,since GNSS measurements require visiting the feature location,a national dataset containing high-accuracy spot elevations has not yet been ***,modern *** maps are devoid of mountain peak or other spot ***,topographic map users continue to demand the display of spot ***,a pilot study was conducted to evaluate the feasibility of automatically generating elevation values at named *** using available elevation *** devised method uses an uphill stepping technique to find the most likely highest point in subsequently higher-resolution elevation *** elevation values are compared to other published *** from 196 summits indicate that values derived from lidar are generally higher,whereas those populated from the one-third arcsecond USGS Seamless 3dEP elevation dataset are generally lower.A thorough understanding of these relationships require the evaluation of more points.

关键词： Spot height summits 3d elevation program geographic names

Virtual ballistic impact testing of Kevlar soft armor:Predictive and validated finite element modeling of the V0-V100 probabilistic penetration response

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defence Technology（防务技术） 2018年第3期14卷 213-225页

作者： gaurav Nilakantan Suzanne Horner Virginia Halls James Zheng Teledyne Scientific&Imaging Thousand OaksCA 91360USA Program Executive Office Soldier Fort BelvoirVA 22060USA

This works presents the first fully validated and predictive capability to model the V_0-V_(100) probabilistic penetration response of a woven fabric using a yarn-level fabric finite element model. The V_0-V_(100) curve describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this paper comprises of a single-layer, fully-clamped, plain-weave Kevlar fabric impacted at the center by a 17-gr, 0.22 cal FSP or fragment-simulating projectile. Each warp and fill yarn in the fabric is individually modeled using 3 d finite elements and the virtual fabric microstructure is validated in detail against the experimental fabric microstructure. Material and testing sources of statistical variability including yarn strength and modulus, inter-yarn friction, precise projectile impact location, and projectile rotation are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-dYNA on the fabric models, with each model comprising unique mappings. The impact velocities together with the outcomes(penetration, nonpenetration) are used to generate the numerical V_0-V_(100) curve which is then validated against the experimental V_0-V_(100) curve. The numerical Vi-Vrdata(impact, residual velocities) is also validated against the experimental Vi-Vrdata. For completeness, this paper also reports the experimental characterization data and its statistical analysis used for model input, viz. the Kevlar yarn tensile strengths, moduli, and inter-yarn friction, and the experimental ballistic test data used for model validation.

关键词： Kevlar 有限元素测试数据验证概率预兆弹道虚拟

Computational study of some potential inhibitors of COVId-19:A dFT analysis

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Quantitative Biology 2022年第4期10卷 341-350页

作者： Prabhat Ranjan Kumar gaurav Tanmoy Chakraborty department of Mechatronics Engineering Manipal University JaipurDehmi Kalan 303007India department of Chemistry and Biochemistry School of Basic Sciences and ResearchSharda UniversityGreater Noida 201310India

Background:There is an urgent demand of drug or therapy to control the *** July 22,2021 the worldwide total number of cases reported is more than 192 million and the total number of deaths reported is more than 4.12 *** countries have given emergency permission for use of repurposed drugs for the treatment of COVId-19 *** report presents a computational analysis on repurposing drugs—tenofovir,bepotastine,epirubicin,epoprostenol,tirazavirin,aprepitant and valrubicin,which can be potential inhibitors of the ***:density functional theory(dFT)technique is applied for computation of these repurposed *** geometry optimization,functional B3LYP/6-311G(d,p)is selected within dFT ***:dFT based descriptors—highest occupied molecular orbital(HOMO)-lowest unoccupied molecular orbital(LUMO)gap,molecular hardness,softness,electronegativity,electrophilicity index,nucleophilicity index and dipole moment of these species are *** and Raman activities are also analysed and *** result shows that the HOMO-LUMO gap of these species varies from 1.061 eV to 5.327 *** aprepitant with a HOMOLUMO gap of 1.419 eV shows the maximum intensity of IR(786.176 km mol‒1)and Raman spectra(15036.702 a.u.).Conclusion:Some potential inhibitors of COVId-19 are studied by using dFT *** study shows that epirubicin is the most reactive compound whereas tenofovir is found to be the most *** analysis and clinical trials of these compounds will provide more insight.

关键词： COVId-19 repurposing drug density functional theory HOMO-LUMO epirubicin aprepitant

Many-body potential for simulating the self-assembly of polymer-grafted nanoparticles in a polymer matrix

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npj Computational Materials 2023年第1期9卷 71-84页

作者： Yilong Zhou Sigbjørn Løland Bore Andrea R.Tao Francesco Paesani gaurav Arya department of Mechanical Engineering and Materials Science Duke UniversityDurhamNC 27708USA Materials Science division Lawrence Livermore National LaboratoryLivermoreCA 94550USA department of Chemistry and Biochemistry University of CaliforniaSan DiegoLa JollaCA 92093USA department of Chemical and NanoEngineering University of CaliforniaSan DiegoLa JollaCA 92023USA

Many-body interactions between polymer-grafted nanoparticles(NPs)play a key role in promoting their assembly into low-dimensional structures within polymer melts,even when the particles are spherical and isotropically ***,capturing such interactions in simulations of NP assembly is very challenging because explicit modeling of the polymer grafts and melt chains is highly computationally expensive,even using coarse-grained ***,we develop a many-body potential for describing the effective interactions between spherical polymer-grafted NPs in a polymer matrix through a machine-learning *** approach involves using permutationally invariant polynomials to fit two-and three-body interactions derived from the potential of mean force *** potential developed here reduces the computational cost by several orders of magnitude,thereby,allowing us to explore assembly behavior over large length and time *** show that the potential not only reproduces previously known assembled phases such as 1d strings and 2d hexagonal sheets,which generally cannot be achieved using isotropic two-body potentials,but can also help discover interesting phases such as networks,clusters,and *** demonstrate how each of these assembly morphologies intrinsically arises from a competition between two-and three-body *** approach for deriving many-body effective potentials can be readily extended to other colloidal systems,enabling researchers to make accurate predictions of their behavior and dissect the role of individual interaction energy terms of the overall potential in the observed behavior.

关键词： grafted polymer potential

Optimization of process for the production of bio-oil from eucalyptus wood

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燃料化学学报 2010年第2期38卷 162-167页

作者： gaurav KUMAR Achyut K PANdA R K SINGH National Institute of Technology Rourkela Orissa PIN： 769008 India Jagannath Institute for Technology and Management Parlakhemundi Orissa India

The pyrolysis of eucalyptus wood was carried out in a batch reactor to optimize the yield of *** of various parameters like feed(particle) size,temperature,presence of catalyst and heating rate on the yield of bio-oil was *** optimum conditions for high yield of bio-oil are for the particle size 2 mm^5 mm(average l/d=12.84/2.03 mm) at 450 ℃ in high heating *** reaction kinetics and the quality of bio-oil produced are independent of the presence of different catalysts like mordenite,kaoline clay,fly ash and silica *** physical properties like odour,colour,PH,viscosity,heating value were *** FT-IR analysis of bio-oil indicates the presence of different functional groups such as monomeric alcohol,phenol,ketones,aldehydes,carboxylic acid,amines,and nitro *** composition of the bio-oil at different conditions was analyzed using GC-MS and found that the components are temperature dependent but independent of catalysts used.

关键词：热反应晶体结构生物能源

Study on sex differences and potential clinical value of threedimensional computerized tomography pelvimetry in rectal cancer patients

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 773-786页

作者： Xiao-Cong Zhou Fei-Yue Ke gaurav dhamija Hao Chen Qiang Wang department of Colorectal Surgery The Dingli Clinical Institute of Wenzhou Medical University(Wenzhou Central Hospital)Wenzhou 325000Zhejiang ProvinceChina Postgraduate Training Base Alliance of Wenzhou Medical University Wenzhou Central HospitalWenzhou 325000Zhejiang ProvinceChina School of International Studies Wenzhou Medical UniversityWenzhou 325000Zhejiang ProvinceChina department of Radiology The Dingli Clinical Institute of Wenzhou Medical University(Wenzhou Central Hospital)Wenzhou 325000Zhejiang ProvinceChina

BACKGROUNd Laparoscopic rectal cancer radical surgery is a complex procedure affected by various ***,the existing literature lacks standardized parameters for the pelvic region and soft tissues,which hampers the establishment of consistent *** To comprehensively assess 16 pelvic and 7 soft tissue parameters through computerized tomography(CT)-based three-dimensional(3d)reconstruction,providing a strong theoretical basis to address challenges in laparoscopic rectal cancer radical *** We analyzed data from 218 patients who underwent radical laparoscopic surgery for rectal cancer,and utilized CT data for 3d pelvic *** anatomical points were carefully marked and measured using advanced 3d modeling *** analyze the pelvic and soft tissue parameters,we emp-loyed statistical methods including paired sample t-tests,Wilcoxon rank-sum tests,and correlation *** The investigation highlighted significant sex disparities in 14 pelvic bone parameters and 3 soft tissue *** demonstrated larger measurements in pelvic depth and overall curvature,smaller measurements in pelvic width,a larger mesorectal fat area,and a larger anterior-posterior abdominal *** contrast,females exhibited wider pelvises,shallower depth,smaller overall curvature,and an increased amount of subcutaneous fat ***,there were no significant sex differences observed in certain parameters such as sacral curvature height,superior pubococcygeal diameter,rectal area,visceral fat area,waist circumference,and transverse abdominal *** The reconstruction of 3d CT data enabled accurate pelvic measurements,revealing significant sex differences in both pelvic and soft tissue *** study design offer potential in predicting surgical difficulties and creating personalized surgical plans for male rectal cancer patients with a potentially“difficult pelvis”,ultimately improving surgical ***

关键词： Computerized tomography Rectal cancer Three-dimensional reconstruction Pelvimetry Sex differences