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Harshavardhan Mahalingam,Anupam Lal,Arup K Mandal,Shrawan Kumar Singh,Shalmoli Bhattacharyya,Niranjan Khandelwal 대한비뇨의학회 2015 Investigative and Clinical Urology Vol.56 No.8
Purpose: This study aimed to assess the accuracy of low-dose dual-energy computed tomography (DECT) in predicting the compositionof urinary calculi. Materials and Methods: A total of 52 patients with urinary calculi were scanned with a 128-slice dual-source DECT scanner byuse of a low-dose protocol. Dual-energy (DE) ratio, weighted average Hounsfield unit (HU) of calculi, radiation dose, and imagenoise levels were recorded. Two radiologists independently rated study quality. Stone composition was assessed after extractionby Fourier transform infrared spectroscopy (FTIRS). Analysis of variance was used to determine if the differences in HU values andDE ratios between the various calculus groups were significant. Threshold cutoff values to classify the calculi into separate groupswere identified by receiver operating characteristic curve analysis. Results: A total of 137 calculi were detected. FTIRS analysis differentiated the calculi into five groups: uric acid (n=17), struvite(n=3), calcium oxalate monohydrate and dihydrate (COM-COD, n=84), calcium oxalate monohydrate (COM, n=28), and carbonateapatite (n=5). The HU value could differentiate only uric acid calculi from calcified calculi (p<0.001). The DE ratio could confidentlydifferentiate uric acid, struvite, calcium oxalate, and carbonate apatite calculi (p<0.001) with cutoff values of 1.12, 1.34, and 1.66,respectively, giving >80% sensitivity and specificity to differentiate them. The DE ratio could not differentiate COM from COM-CODcalculi. No study was rated poor in quality by either of the observers. The mean radiation dose was 1.8 mSv. Conclusions: Low-dose DECT accurately predicts urinary calculus composition in vivo while simultaneously reducing radiation exposurewithout compromising study quality.
Harshavardhan B. Rao,Paul K. Vincent,Priya Nair,Anoop K. Koshy,Rama P. Venu 대한소화기내시경학회 2022 Clinical Endoscopy Vol.55 No.5
Background/Aims: In patients undergoing endoscopic retrograde cholangiopancreatography (ERCP), calcineurin activates zymogen, which results in pancreatitis. In this study, we aimed to determine the efficacy of tacrolimus, a calcineurin inhibitor, in preventing post-ERCP pancreatitis (PEP). Methods: This was a prospective pilot study in which patients who underwent ERCP received tacrolimus (4 mg in two divided doses); this was the Tac group. A contemporaneous cohort of patients was included as a control group. All patients were followed-up for PEP. PEP was characterized by worsening abdominal pain with an acute onset, elevated pancreatic enzymes, and a duration of hospital stay of more than 48 hours. Serum tacrolimus levels were measured immediately before the procedure in the Tac group. Results: There were no differences in the baseline characteristics between the Tac group (n=48) and the control group (n=51). Only four out of 48 patients (8.3%) had PEP in the Tac group compared to eight out of 51 patients (15.7%) who had PEP in the control group. The mean trough tacrolimus level in patients who developed PEP was significantly lower (p<0.05). Conclusions: Oral tacrolimus at a cumulative dose of 4 mg safely prevents PEP. Further randomized controlled studies are warranted to establish the role of tacrolimus in this context.
(Zn, Ni)-ferrite nanoparticles for promoted osteogenic differentiation of MC3T3-E1 cells
Harshavardhan Mohan,Natesan Karthi,Pavithra Muthukumar Sathya,Vaikundamoorthy Ramalingam,Srivalli Thimmarayan,호싸인암자드,Adithan Aravinthan,신태호 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-
The structural composition and functionality of bone tissues has been significantly impacted due to progressiveageing, thereby necessitating effective strategies that are not just about temporary cure butabout permanent regeneration of tissues, one such being regenerative medicine. Of the several noveltiesin the field, the provocation of osteogenesis involving nanoparticles has gained significant attention fortheir heightened efficiency and cost effectiveness. Magnetic materials in particular have been increasinglypaid attention to owing to their edge over stability, non-toxicity and feasibility to spatially trackusing MRI. The present study involves the synthesis of Zn and Ni doped ferrite ((Zn, Ni)-ferrite) nanoparticlesinvolving chemical co-precipitation method. The materials were evaluated against MC3T3 cellstowards ROS induced osteogenic differentiation properties, and the results implied very less toxicity evenat concentration surpassing 50 lg/ml in addition to the void of necrosis after treatment with 2.5 and5 lg/ml of (Zn, Ni)-ferrite. FACS results implied 1% cell staining with propidium iodide after 24 h exposureat 2.5 lg/ml concentrations of (Zn, Ni)-ferrite, thereby substantiating (Zn, Ni)-ferrite as a potentialbiomaterial in favor of regenerative medicine.
Design, Synthesis In Vitro Anticancer Activity and Docking Studies of (−)-Catechin Derivatives
Deepak Kumar,S. J. Harshavardhan,Sridhar Chirumarry,Y. Poornachandra,장기완,C. Ganesh Kumar,윤용진,Bao-Xiang Zhao,Jun-Ying Miao,신동수 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.2
Novel series of ()-catechin derivatives 1a-l were synthesized, characterized and assayed for their cytotoxicity against four selected human cancer cell lines by standard MTT assay method. Most of the compounds significantly active among which 1d exhibited promising activity with IC50 values of 2.5, 4.8 and 5.4 μM specifically against hepatocellular liver carcinoma (HepG2), lung adenocarcinoma (A549) and prostate (DU-145) cell lines, while compound 1j showed promising cytotoxicity against human breast adenocarcinoma MDA-MB-231 (IC50 value of 6.6 μM). Compounds 1a, 1d, 1e, 1f and 1j exhibited broad spectrum cytotoxicity against all the cell lines screened. Molecular docking studies of compound 1d established the good binding affinity and are in favor of the observed biological activity. These data collectively suggest that compound 1d could serve as a new template for further optimization as anticancer agent.
Synthesis of POSS Derived Organic-Inorganic Hybrid Esters for Insulating Oil Applications
Choi, Kyeong-Min,Harshavardhan, S.J.,Sridhar, Ch.,Vijaykumar, B.V.D.,Kumar, Deepak,Jang, Kiwan,Lee, Man-Sig,Shin, Dong-Soo Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.9
In this work, a new family of polyhedral oligomeric silsesquioxanes (POSS) based esters have been synthesized that consists eight ester functional groups. These are classified into Type-I and Type-II esters based on the starting materials, octakis(3-chloropropyl)silsesquioxane (Cl-POSS) and octakis(3-hydroxypropyldimethylsiloxy) octasilsesquioxane (OHPS) respectively. These new POSS type ester moieties can be used as insulating oils and oil additives in the transformers and also considered to be alternatives to mineral and vegetable oils that are presently used in the insulation system.
Madhan Mohan,Evgeny Tsyplakov,Christian Winter,Harshavardhan Marabathina 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
IGCTs are increasingly becoming the device of choice for high power applications such as HVDC and FACTS with low losses and high reliability. Voltage Source Converters (VSC) with IGCT semiconductors are the choice in high demanding applications with high power and current ratings primarily due to low overall losses and high power handling capability. IGCT circuit typically require a di/dt limiting snubber for the protection of freewheeling diodes from huge current derivatives and so an over voltage limiting mechanism for the protection of IGCTs. This paper presents the performance evaluation of IGCT and its Clamp Circuit in terms of losses, focusing on MMC converter cells for use in high power applications such as HVDC, FACTS. The proposed method is based on look up tables generated for clamp circuit energy dissipation for the different converter switching states and is synchronized with the actual switching transitions. Additionally, the temperature dependency of the reverse recovery current for the freewheeling diode losses also considered. Hence, it yields an accurate, yet computationally efficient method of loss calculation. The results for IGCT based MMC converters are also compared with IGBT based MMC converter to clearly highlight the advantages of one over the other.
Synthesis of POSS Derived Organic-Inorganic Hybrid Esters for Insulating Oil Applications
Kyeong-min Choi,S. J. Harshavardhan,Ch. Sridhar,B. V. D. Vijaykumar,Deepak Kumar,장기완,이만식,신동수 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.9
In this work, a new family of polyhedral oligomeric silsesquioxanes (POSS) based esters have been synthesized that consists eight ester functional groups. These are classified into Type-I and Type-II esters based on the starting materials, octakis(3-chloropropyl)silsesquioxane (Cl-POSS) and octakis(3-hydroxypropyldimethylsiloxy) octasilsesquioxane (OHPS) respectively. These new POSS type ester moieties can be used as insulating oils and oil additives in the transformers and also considered to be alternatives to mineral and vegetable oils that are presently used in the insulation system.
Deepak Kumar,Sridhar Chirumarry,B. V. D. Vijaykumar,S. J. Harshavardhan,장기완,이동하,신동수 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.4
An efficient synthesis of (3Z,6Z)-cis-9,10-epoxy-3,6-henicosadiene (1), the major component of sex pheromone of saltmarsh caterpillar moth Estigmene acrea (Drury), was accomplished from commercially available pentadec-3-yn-1-ol and bromoundecane. Chirality was introduced by employing Sharpless asymmetric dihydroxylation on cis-olefin intermediate in the synthesis of 1, for the first time. The other key reactions include metal-dissolving coupling, Lindlar's catalyst-assisted partial hydrogenation, one-pot, three-step epoxidation from vicinal diol, and Wittig olefination. The overall yield of 1 was 24.7% in eight steps. The efficiency and simplicity of this synthesis allow the potential use of pheromone 1 in pest management programs.