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Deepak Patel,Prasenjit Biswas,Anil Kumar,Hiren R. Kotadia,Archana Mallik,Sanjeev Das 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7
The present investigation focuses on grain refinement in pure aluminum and its alloy under mechanical stirring with a verylow degree of forced convection of 800 rpm as compared to reported values of up to 8000 rpm during direct chill castingprocess (DC). Commercially pure aluminum (99.7%) and Al6082 alloy billets were fabricated in an in-house designed DCcasting simulator. Mechanical forced convection (MFC) was applied to the melt during casting by a common four-bladedimpeller. The microstructural properties of the as-cast billets have been analysed to study the effect of MFC during casting andsolidification. The structure of both Al and its alloy is found to be refined in presence of MFC as compared to conventionalDC. A combination of simulation, experimental and theoretical approaches has been used to determine the effect of MFCin melt-temperature distribution to propose the mechanism of grain refinement. It has been observed that MFC prominentlyreduces the temperature gradient and extends undercooling time, resulting in fine grain structure.
Deepak Kumar,Vipin Kumar Singh,Narayan Prasad Yadav,Sudeep Tandon,Karuna Shanker,Chandan Singh Chanotiya,Narendra Kumar,Puja Khare,Anirban Pal,Debabrata Chanda,Dharmendra Saikia,Yusuf Hussain,Abha Mee 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-
Gymnema sylvestre is an important medicinal plant, but a method for preparing standardized extractenriched with biomarkers is not available. The practiced crude hydro-alcoholic extracts of G. sylvestrecontained a few percentage of gymnemic acids (GAs). The enrichment of GAs in preprared extracts isessential from a pharmacology point of view. Presently, a scale-up process has been developed forpreparing G. sylvestre standardized extract (Gym-EEXT). Crude extract (Gym-Crude) was prepared in10-kg batches to obtain a yield of 268.1 mg/g, but GAs was merely 9 mg/g (GA-IV 6.7 mg/g, and GAXVII2.3 mg/g) in 30 % ethanol–water solvent at 50 C in 5 h. Further, Gym-Crude was processed throughpolymer-matrix-adsorption techniques for getting Gym-EEXT (150.9 mg/g) with improved percentage ofGAs (>10 %) comprised of deacylgymnemic acid (DGA: 8.9 mg/g), gymnemagenin (2.3 mg/g), GA-IV(78.6 mg/g), and GA-XVII (10.2 mg/g). For safety aspects, the pesticide residues, solvent residues, heavymetal, aflatoxins, and mutagenicity in Gym-EEXT were below the detection limits. Hence, Gym-EEXT wasenriched with GAs, and fully safe with compliance according to USP-561. An insignificant effect of Gym-EEXT on vitals of experimental mice was observed in acute and sub-acute oral-toxicityexperiments. Gym-EEXT significantly improved the blood glucose metabolism, and hence, it potentiallyreduces hyperglycaemia. Unique chromatographic protocols were developed for the isolation of biomarkerson a 1-kg scale from Gym-Crude with yield of gymnemagenin (5.5 %), and DGA (4.6 %). Finally, a novel,scientifically validated, and the scale-up process has been developed for the preparation of Gym-EEXTalong with an exclusive protocol for isolating its biomarkers.
Deepak Kumar Singh,Shankar Diwakar,Vipin Kumar Chand,Singh Rakesh Kumar,Singh Neha 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.6
Complex craniovertebral junction (CVJ) defects account for a considerable proportion of CVJ diseases. Given the heavily assimilated C1, an unfavorable C1–C2 joint orientation, an overriding C2 superior facet, a low-hanging occiput, and an abnormal vertebral artery course with a high-riding vertebral artery, placement of C1 lateral mass screws might be difficult. To address this, a novel technique for placing C1 lateral mass screws that avoid vertebral artery injury, low-hanging occiput, and overriding C2 superior facet was developed in this study. This approach enables firm fixation of C1–C2 even in difficult situations where the placement of the C1 lateral mass is challenging.
Ruptured mirror DACA aneurysm: A rare case report and review of literature
Deepak Kumar Singh,Prevesh Kumar Sharma,Arun Kumar Singh,Vipin Kumar Chand 대한뇌혈관외과학회 2023 Journal of Cerebrovascular and Endovascular Neuros Vol.25 No.3
Bilateral distal anterior cerebral artery (DACA) aneurysms also called “kissing aneurysms” or “mirror aneurysm” are extremely rare, accounting for only 0.2% of all intracranial aneurysms. There have only been a few examples of mirror DACA aneurysms reported in the literature. Here, we report a rare case of mirror DACA aneurysm in a middle aged female with its successful clipping. Patient was admitted with severe headache and altered sensorium. Computed tomography (CT) head was suggestive of anterior inter-hemispheric hematoma. Digital subtraction angiography (DSA) was done which was suggestive of two distal anterior cerebral artery aneurysms located at same anatomical position. It was treated through microsurgical clipping. Mirror image DACA aneurysms are rare occurrence. All patients with ruptured DACA aneurysms should have angiography with 3D reconstruction studies. This aids in determining the aneurysm’s morphology and planning treatment accordingly.
Antimicrobial and docking studies of (-)-catechin derivatives
Kumar, Deepak,Poornima, M.,Kushwaha, R.N.,Won, Tae-Jin,Ahn, Chuljin,Kumar, C. Ganesh,Jang, Kiwan,Shin, Dong-Soo The Korean Society for Applied Biological Chemistr 2015 Applied Biological Chemistry (Appl Biol Chem) Vol.58 No.4
Antimicrobial activities of (-)-catechin derivatives were assayed for their antibacterial and antifungal activities against gram positive, gram negative bacteria, and fungi. Most of the compounds significantly active among which Compounds 1a, 1b, and 1c showed excellent antibacterial for both gram negative and gram positive bacteria, these compounds also exhibited excellent antifungal activity more than the standard drug. Molecular docking studies of Compounds 1a and 1b established good binding affinity with ATP-binding pocket of DNA gyrase and are in favor of the observed biological activity. These data collectively suggest that Compounds 1a and 1b could serve as a novel antimicrobial agent.
MHD Pulsatile Flow and Heat Transfer of Two Immiscible Couple Stress Fluids Between Permeable Beds
Kumar, Deepak,Agarwal, Manju Department of Mathematics 2021 Kyungpook mathematical journal Vol.61 No.2
The present paper addresses magnetohydrodynamic pulsating flow and heat transfer of two immiscible, incompressible, and conducting couple stress fluids between two permeable beds. The flow between the permeable beds is assumed to be governed by Stokes' [28] couple stress fluid flow equations, whereas the dynamics of permeable beds is determined by Darcy's law. In this study, matching conditions were used at the fluid-fluid interface, whereas the B-J slip boundary condition was employed at the fluid-porous interface. The governing equations were solved analytically, and the expressions for velocity, temperature, mass flux, skin friction, and rate of heat transfer were obtained. The analytical expressions were numerically evaluated, and the results are presented through graphs and tables.
Deepak Kumar Jha,Anil Thakur,Mukul Jain,Arvind Arya,Chandrabhushan Tripathi,Rima Kumari,Suman Kushwaha 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.6
Study Design: Prospective clinical study. Purpose: To observe the usefulness of anterior cervical osteophytes as intrinsic markers for spinal level localization (SLL) during sub-axial cervical spinal surgery via the anterior approach. Overview of Literature: Various landmarks, such as the mandibular angle, hyoid bone, thyroid cartilage, first cricoid ring, and C6 carotid tubercle, are used for gross cervical SLL; however, none are used during cervical spinal surgery via the anterior approach. We present our preliminary assessment of SLL over anterior vertebral surfaces (i.e., intrinsic markers) in 48 consecutive cases of anterior cervical spinal surgeries for the disc-osteophyte complex (DOC) in degenerative diseases and granulation or tumor tissue associated with infectious or neoplastic diseases, respectively, at an ill-equipped center. Methods: This prospective study on patients undergoing anterior cervical surgery for various sub-axial cervical spinal pathologies aimed to evaluate the feasibility and accuracy of SLL via intraoperative palpation of disease-related morphological changes on anterior vertebral surfaces visible on preoperative midline sagittal T1/2-weighted magnetic resonance images. Results: During a 3-year period, 48 patients (38 males,10 females; average age, 43.58 years) who underwent surgery via the anterior approach for various sub-axial cervical spinal pathologies, including degenerative disease (n= 42), tubercular infection (Pott’s disease; n=3), traumatic prolapsed disc (n=2), and a metastatic lesion from thyroid carcinoma (n=1), comprised the study group. Intrinsic marker palpation yielded accurate SLL in 79% of patients (n=38). Among those with degenerative diseases (n=42), intrinsic marker palpation yielded accurate SLL in 76% of patients (n=32). Conclusions: Intrinsic marker palpation is an attractive potential adjunct for SLL during cervical spinal surgeries via the anterior approach in well-selected patients at ill-equipped centers (e.g., those found in developing countries). This technique may prove helpful when radiographic visualization is occasionally inadequate.
Synthesis, Antioxidant and Molecular Docking Studies of (-)-Catechin Derivatives
Kumar, Deepak,Kumar, Raj,Ramajayam, R.,Lee, Keun Woo,Shin, Dong-Soo Korean Chemical Society 2021 대한화학회지 Vol.65 No.2
12 kinds of (-)-catechin derivatives were designed and synthesized. The catechin derivatives were evaluated their antioxidant activities using DPPH method. Most of them showed good antioxidant activity, particularly compounds 1d, 1e and 1j exhibited more activity than butylated hydroxytoluene (BHT). Molecular docking studies for compounds 1d, 1e and 1j with STAT1 showed not only sufficent characteristics binding cavity but also agreement with the observed biological activity. Acording to docking results, the compounds showed greater than hydrogen bonding, hydrophobic interactions, electrostatic interactions, and Van der Waals interactions as compared to the reference compound. They formed hydrogen bonds with important residues such as Lys566, His568, Leu570, and Phe644. The compounds showed a novel hydrogen bonding interaction with Arg649, which was not reported previously. Our results might suggest the compounds could serve as a novel anti-oxidant agent.
Kumar, Banothu Kiran,Bhatia, Prateek,Trehan, Amita,Singh, Ajit Pal,Kaul, Deepak,Bansal, Deepak Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.17
DNA ploidy is an important prognostic parameter in paediatric B-ALL, but the significance of the S-phase fraction is unclear. In present study, DNA ploidy was assessed in 40 pediatric B-ALL cases by flow cytometry. The DI (DNA index) and percentage of cells in S-phase were calculated using Modfit software. Aneuploidy was noted in 26/40 (65%) cases. A DI of 1.10-1.6 (hyperdiploidy B) was noted in 20/40 (50%) and 6/40 (15%) had a DI>1.60 (triploid and tetraploid range). Some 14/40 (35%) cases had a diploid DI between 0.90-1.05. None of the cases had a DI <0.90 (hypodiploid) or in the 1.06-1.09 (hyperdiploid A) range. The mean S-phase fraction was 2.6%, with 24/40 (60%) having low and 16/40 (40%) high S-phase fractions. No correlation was noted with standard ALL risk and treatment response factors with DI values or S-phase data, except for a positive correlation of low S-phase with high NCI risk category (p=0.032). Overall frequency of hyperdiploidy in our cohort of B-ALL patients was very high (65%). No correlation between hyperdiploidy B and low TLC or common B-phenotype was observed in our study as 42% cases with DI 1.10-1.6 had TLC> $50{\times}10^9$ and 57.1% CD 10 negativity. The study also highlighted that S-phase fraction analysis does not add any prognostic information and is not a useful parameter for assessment in ALL cases. However, larger studies with long term outcome analysis are needed to derive definitive conclusions.