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Novel PA encapsulated PCL hybrid coating for corrosion inhibition of biodegradable Mg alloys:A triple triggered self-healing response for synergistic multiple protection

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Journal of Magnesium and Alloys 2023年第4期11卷 1440-1460页

作者： navdeep singh grewal Uma Batra Kamal Kumar Anil Mahapatro Department of Metallurgical and Materials Engineering Punjab Engineering CollegeChandigarh 160012India Department of Mechanical Engineering Punjab Engineering CollegeChandigarh 160012India Department of Biomedical Engineering Wichita State UniversityWichitaKS 67260USA

Surface coatings have been extensively used to control the degradation rate of Mg alloys for bioimplant ***,these coatings only act as passive *** corrosive media,structural damage impairs their barrier properties,resulting in rapid degradation of Mg *** present study incorporates phytic acid(PA)as a healing agent in polycaprolactone(PCL)microcapsules with a unique honeycomb core matrix to obtain a self-healing PA-PCLcaps *** contact between simulated body fluid(SBF)and PA-PCLcaps coated ZM21 exhibited Cassie-Baxter interfacial states,resulting in significant hydrophobicity with a contact angle(CA)of *** corrosion potential(Ecorr)and current density(Icorr)were found to be-0.28 V and 1.1×10^(-9)A/cm^(2),respectively,for PA-PCLcaps coating,resulting in biosafe corrosion rate of 2.5×10^(-4)mm/*** mechanical scratching,rapid HA mineralization at scratched regions recovered the hydrogen evolution rate(HER,0.36 mL/cm^(2)/day)and pH change(pH 7.10)of scratched PA-PCLcaps coated ZM21 samples to corresponding unscratched samples within one day of *** coating’s self-healing ability could be attributed to PA released from punctured microcapsules,which facilitates HA *** pH-triggered(pH 10)and Mg(II)-triggered(5 mM)conditions enhanced PA release from PA-PCLcaps coating by 2.5 and 3.1 times,*** a result,dense HA mineralization occurred,which protects the coating from structural defects and ensures its durability in stimulating *** findings of present study provide new insight for design of multiple stimuli-feedback based self-healing coatings on biodegradable Mg alloys.

关键词： Self-healing coating Corrosion resistance Magnesium alloy Phytic acid Polycaprolactone microcapsules

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Evaluation of corrosion resistance, mechanical integrity loss and biocompatibility of PCL/HA/TiO_(2) hybrid coated biodegradable ZM21 Mg alloy

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Journal of Magnesium and Alloys 2022年第11期10卷 3179-3204页

作者： navdeep singh Uma Batra Kamal Kumar Anil Mahapatro Department of Metallurgical and Materials Engineering Punjab Engineering CollegeChandigarh 160012India Department of Mechanical Engineering Punjab Engineering CollegeChandigarh 160012India Department of Biomedical Engineering Wichita State UniversityWichitaKS 67260United States

A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in physiological media. The prepared hybrid coating was dip coated over ZM21 from HA/TiO_(2)and PCL solutions followed by creating a microporous PCL layer by utilizing Non-solvent Induced Phase Separation(NIPS) technique. The electrochemical measurement and in-vitro degradation study in SBF after 28 days showed that the PCL/HA/TiO_(2) hybrid coating reduced H2 evolution rate, weight loss, and corrosion rate by 64, 116 and 118 times respectively, as compared to uncoated ZM21 samples. The surface studies carried out using SEM-EDX, FTIR and XRD revealed formation of highly stable 3d flower-like HA crystals with Ca/P ratio of 1.60 in the PCL micropores. This dense apatite growth effectively protected the PCL/HA/TiO_(2)hybrid coated samples to maintain the good mechanical integrity even after 28 days of immersion as compared to HA/TiO_(2)composite coated, As-polished(A/P) and As-machined(A/M) samples. The failure analysis of samples under mechanical loading were performed using *** in-vitro cellular viability of L929 fibroblast cells on PCL/HA/TiO_(2)hybrid coating was found 50.47% higher with respect to control group,whereas bacterial viability was supressed by 57.15 and 62.35% against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial models. The comprehensive assessment indicates PCL/HA/TiO_(2)hybrid coating as a suitable candidate to delay early degradation and mechanical integrity loss of Mg-based alloys for devising biodegradable orthopaedic implant.

关键词： Magnesium alloy Surface modification Hybrid coating Mechanical integrity loss Degradation rate Biocompatibility

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Investigating TiO_(2)-HA-PCL hybrid coating as an efficient corrosion resistant barrier of ZM21 Mg alloy

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Journal of Magnesium and Alloys 2021年第2期9卷 627-646页

Surface modification for improving corrosion resistance of Mg alloys is highly demanded for degradable orthopedic and cardiovascular *** research reports the design and development of TiO_(2)–HA composite and novel TiO_(2)–HA–PCL hybrid coating belonging to the unique class of inorganic organic hybrid with striking features that are explored for the first time in the corrosion resistance of Mg ***–gel dip coating combined with non-solvent induced phase separation is used to create the hybrid ***_(2)–HA–PCL hybrid coating introduces strong hydrogen bonding between TiO_(2)–HA inorganic matrix and PCL organic layer in addition to the Vander wall electrostatic interaction of the later with the Mg substrate which in turn enhance adhesion strength to about 1.5 times of TiO_(2)–HA *** corrosion potentials for TiO_(2)–HA–PCL and TiO_(2)–HA were found to be-0.407 V and-1.017 V(vs Ag/Ag Cl),*** current densities of TiO_(2)–HA–PCL and TiO_(2)–HA were found to be 7.31×10^(-8)A/cm^(2)and 4.03×10^(-4)A/cm^(2)*** corrosion resistance of coatings was confirmed by immersion testing by weight loss,pH changes and H_(2)evolution measurements at interval of 7 days till 28 *** present TiO_(2)–HA–PCL coating in comparison to TiO_(2)–HA coating demonstrate nearly 6%less weight *** outcome of the present work was compared with the similar coatings in recent *** work done ingresses enhancing the corrosion resistance of Mg alloys,which fulfill the dreams of future degradable orthopedic and cardiovascular devices.

关键词： Corrosion resistance TiO_(2)-HA-PCL Contact angle Adhesion strength

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Psychotic symptoms in bipolar disorder and their impact on the illness:A systematic review

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World Journal of Psychiatry 2022年第9期12卷 1204-1232页

作者： Subho Chakrabarti navdeep singh Department of Psychiatry Postgraduate Institute of Medical Education and ResearchChandigarh 160012UTIndia

BACKGROUND Lifetime psychotic symptoms are present in over half of the patients with bipolar disorder(BD)and can have an adverse effect on its course,outcome,and ***,despite a considerable amount of research,the impact of psychotic symptoms on BD remains unclear,and there are very few systematic reviews on the *** To examine the extent of psychotic symptoms in BD and their impact on several aspects of the *** The Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were *** electronic literature search of six English-language databases and a manual search was undertaken to identify published articles on psychotic symptoms in BD from January 1940 to December *** of the relevant Medical Subject Headings terms were used to search for these *** were selected after a screening phase,followed by a review of the full texts of the *** of the methodological quality of the studies and the risk of bias was conducted using standard *** This systematic review included 339 studies of patients with *** psychosis was found in more than a half to two-thirds of the patients,while current psychosis was found in a little less than half of *** were more common than hallucinations in all phases of *** a third of the patients reported first-rank symptoms or mood-incongruent psychotic symptoms,particularly during manic *** symptoms were more frequent in bipolar type I compared to bipolar type II disorder and in mania or mixed episodes compared to bipolar *** psychotic symptoms were not more severe in BD,the severity of the illness in psychotic BD was consistently *** was usually associated with poor insight and a higher frequency of agitation,anxiety,and hostility but not with psychiatric *** was consistently linked with increased rates and the duration of hospitalizations,switching amo

关键词： Psychotic symptoms Bipolar disorder Extent Impact

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Enhanced cavitation erosion resistance of a friction stir processed high entropy alloy

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International Journal of Minerals,Metallurgy and Materials 2020年第10期27卷 1353-1362页

作者： Rakesh B.Nair H.S.Arora Harpreet singh grewal Surface Science and Tribology Lab Department of Mechanical EngineeringShiv Nadar UniversityGautam Buddha NagarUttar Pradesh 203207India

Friction stir processing of an Al0.1CoCrFeNi high entropy alloy(HEA)was performed at controlled cooling conditions(ambient and liquid submerged).Microstructural and mechanical characterization of the processed and as-cast HEAs was evaluated using electron backscatter diffraction,micro-hardness testing and *** under the submerged cooling condition showed elongated grains(10μm)with fine equiaxed grains(2μm)along the boundary compared to the coarser grain(~2 mm)of as-cast *** hardness showed remarkable improvements with four(submerged cooling condition)and three(ambient cooling condition)times that of as-cast HEA(HV^150).The enhanced hardness is attributed to the significant grain refinement in the processed *** erosion behavior was observed for samples using an ultrasonication *** of the HEAs showed better cavitation erosion resistance than the stainless steel *** sample processed under a submerged liquid condition showed approximately 20 and 2 times greater erosion resistance than stainless steel 316L and ascast HEA,*** enhanced erosion resistances of the processed HEAs correlate to their increased hardness,resistance to plasticity,and better yield strength than the as-cast *** surface of the tested samples showed nucleation and pit growth,and plastic deformation of the material followed by fatigue-controlled disintegration as the primary material removal mechanism.

关键词： cavitation erosion microstructure mechanical properties surface engineering

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Progress in bioactive surface coatings on biodegradable Mg alloys:A critical review towards clinical translation

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Bioactive Materials 2023年第1期19卷 717-757页

作者： navdeep singh Uma Batra Kamal Kumar Neeraj Ahuja Anil Mahapatro Department of Metallurgical and Materials Engineering Punjab Engineering CollegeChandigarh160012India Department of Mechanical Engineering Punjab Engineering CollegeChandigarh160012India Department of Biomedical Engineering Wichita State UniversityWichitaKS67260United States

Mg and its alloys evince strong candidature for biodegradable bone implants,cardiovascular stents,and wound closing ***,their rapid degradation rate causes premature implant failure,constraining clinical ***-functional surface coatings have emerged as the most competent strategy to fulfill the diverse clinical requirements,besides yielding effective corrosion *** article reviews the progress of biodegradable and advanced surface coatings on Mg alloys investigated in recent years,aiming to build up a comprehensive knowledge framework of coating techniques,processing parameters,performance measures in terms of corrosion resistance,adhesion strength,and *** developed conversion and deposition type surface coatings are thoroughly discussed by reporting their essential therapeutic responses like osteogenesis,angiogenesis,cytocompatibility,hemocompatibility,anti-bacterial,and controlled drug release towards in-vitro and in-vivo study *** challenges associated with metallic,ceramic and polymeric coatings along with merits and demerits of various coatings have been *** use of multilayered hybrid coating comprising a unique combination of organic and inorganic components has been emphasized with future perspectives to obtain diverse bio-functionalities in a facile single coating system for orthopedic implant applications.

关键词： Mg alloys Corrosion resistance Bio-functionality Conversion coating Multilayered hybrid coating Coating failures

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LQG Controller Design Applied to a Pneumatic Stewart-Gough Platform

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International Journal of Automation and computing 2012年第1期9卷 45-53页

作者： Karmjit singh grewal Roger Dixon John Pearson Control System Group Department of Electronic and Electrical EngineeringLoughborough University Systems Engineering Innovation Centre(SEIC) British Aerospace and Marconi Electronic Systems(BAE Systems)

This paper is concerned with the practical application control of a pneumatically actuated Stewart-Gough platform with 6-degrees of freedom （6-DOF）. The control approach for motion control of the platform is presented using a modern control technique, namely, linear quadratic Gaussinn （LQG） with reference tracking. The LQG controller is the combination of a Kalman filter, i.e., a linear-quadratic estimator （LQE） with a linear-quadratic regulator （LQR）. The robustness of the control scheme is accessed under various load conditions, and the experimental results are shown.

关键词： Real-time control Kalman filter inverse kinematics pneumatic actuation Stewart-Gough platform

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Acute renal failure secondary to lupus nephritis confirmed by renal biopsy with an unusually normal immunological profile

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Case Reports in Clinical Medicine 2014年第1期3卷 6-9页

作者： Zhigang Liu Andrew Ofosu Richard Williams navdeep grewal Department of Medicine MedStar Harbor Hospital Baltimore USA Department of Medicine MedStar Harbor Hospital Baltimore USA Ross University School of Medicine Roseau Commonwealth of Dominica

The gold standard to diagnose the lupus nephritis is the renal biopsy. It provides information not only for diagnosis but also for the treatment plan and the prognosis. Laboratory studies, including the immunological profile, play an essential role in diagnosing and evaluating the lupus nephritis activity. The patient is unlikely to have the active lupus nephritis with the combination of anti-ds DNA, anti-C1q, C3 and C4 being within normal limits. In this case report, we present a patient with moderately active diffuse proliferative lupus glomerulonephritis (Class IV) confirmed by the renal biopsy, while her immunological profile is unusually normal.

关键词： Lupus Nephritis Anti-Ds DNA C3 C4 Immunological Profile

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Reinforcement Learning Based Obstacle Avoidance for Autonomous Underwater Vehicle

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Journal of Marine Science and Application 2019年第2期18卷 228-238页

作者： Prashant Bhopale Faruk Kazi navdeep singh Electrical Engineering Department Veermata Jijabai Technological Institute

Obstacle avoidance becomes a very challenging task for an autonomous underwater vehicle(AUV)in an unknown underwater environment during exploration *** control in such case may be achieved using the model-based classical control techniques like PID and MPC but it required an accurate mathematical model of AUV and may fail due to parametric uncertainties,disturbance,or plant model *** the other hand,model-free reinforcement learning(RL)algorithm can be designed using actual behavior of AUV plant in an unknown environment and the learned control may not get affected by model uncertainties like a classical control *** model-based control model-free RL based controller does not require to manually tune controller with the changing environment.A standard RL based one-step Q-learning based control can be utilized for obstacle avoidance but it has tendency to explore all possible actions at given state which may increase number of *** a modified Q-learning based control approach is proposed to deal with these problems in unknown ***,function approximation is utilized using neural network(NN)to overcome the continuous states and large statespace problems which arise in RL-based controller *** proposed modified Q-learning algorithm is validated using MATLAB simulations by comparing it with standard Q-learning algorithm for single obstacle ***,the same algorithm is utilized to deal with multiple obstacle avoidance problems.

关键词： Obstacle avoidance Autonomous underwater vehicle Reinforcement learning Q-learning Function approximation

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A survey of analgesic and anti-inflammatory drug prescription for oral implant surgery

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Plastic and Aesthetic Research 2015年第1期2卷 51-55页

作者： Rahul Datta Yasmin grewal Jaspreet singh Batth Amandeep singh Department of Oral and Maxillofacial Surgery Rayat Bahra Dental College and HospitalMohali 140104PunjabIndia Department of Public Health Dentistry Rayat Bahra Dental College and HospitalMohali 140104PunjabIndia Department of Conservative Dentistry and Endodontics BRS Dental College and HospitalPanchkula 134109PunjabIndia Department of Pharmacology Shri Guru Ram Rai Institute of Medical and Health SciencesPatel NagarDehradun 248001UttarakhandIndia

Aim:This study was conducted to determine the preferred analgesic and anti-inflammatory drugs prescribed by oral implantologists in ***:A structured questionnaire was distributed to 332 dentists to gather information regarding their prescription habits for analgesics and anti-inflammatory *** distributions were computed by type of drug being prescribed and the protocol ***:Analysis of data showed that majority of dentists(85.8%,n=285)prescribed conventional non-steroidal anti-inflammatory drugs(NSAIDs)for implant *** most common prescription was ibuprofen with paracetamol combination(32.2%,n=107)followed by diclofenac(20.2%,n=67).Most dentists reported prescribing different NSAIDs for the same procedure in different patients(64.7%,n=215).Only,35.5%(n=118)followed the peri-operative *** prescription of steroids was done by only 33.7%(n=112).Conclusion:Our study illustrates that the general trend of analgesic and anti-inflammatory drug prescription for dental implant surgery among Indian dentists is mostly in accordance with the guidelines for pain management ***,it is noteworthy that a few dentists do prescribe drugs not primarily indicated for dental pain management and use widely varying protocols for the ***,in order to avoid potential complications,it is essential to raise awareness of among the dental practitioners of the appropriate indications and dosage regimen of specific drugs.

关键词： Dental implants non‑steroidal anti‑inflammatory drugs prescription steroid protocol

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