C2 Superior Facetal Osteotomy: A Novel Technique in Complex Craniovertebral Junction Surgery for C1 Lateral Mass Screw Placement

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.

Radioprotective and Antioxidant Activity of Fractionated Extracts of Berries of Hippophae rhamnoides

Rakesh Kumar Sharma,Raman Chawla,Rajesh Arora,Shikha Singh,Ravinder Kumar Sagar,Raj Kumar,Ashok Sharma,Manju L. Gupta,Surender Singh,Jagdish Prasad,Haider A. Khan,Anand Swaroop,A.K. Sinha,A.K. Gupta,R 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.1

Plants are an abundant source of medicinal compounds, some of which are useful in combating free radical-1002 (flavonoid-poor fraction) of Hippophae rhamnoideswere screened on the basis of their reducing power in the aqueousphase. REC-1001 was selected for further study, since it exhibited 27.38 times higher antioxidant activity than REC-1002.REC-1001 also showed significant (P. .05) membrane protection potential at 50 .g/mL, which was attributed to its abilityto scavenge peroxyl radicals (64.82. 1.25% scavenging within 1,440 min). A significant (P. .05) difference of 67.02% infree radical scavenging activity at 1,000 ng/mL between REC-1001 and vitamin E demonstrated the extract fraction’s worthc-tion. Further, REC-1001 was found to be nontoxic up to 200 mg/kg of body weight. This research suggests that the REC-1001 fraction of H. rhamnoidesextract is a safe and effective antioxidant nutraceutical product.

In-situ braking torque and temperature analysis of two-wheeler drum brake in friction braking

Rakesh Kumar Singh,Chiranjit Sarkar 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

Generally, two-wheelers consist of a drum brake on the rear wheel. The performance of the brake deteriorates drastically due to the continuous use of brakes during driving. Thus, studying brake performance in the worst conditions, where brakes are applied back to back after a fixed time interval, becomes essential. To fulfill this, the in-situ braking torque behavior of the two-wheeler drum brake is studied experimentally, and the in-situ thermal behavior is studied experimentally and numerically in the present paper. A new test rig is designed using a motor, torque sensor, data acquisition system, and drum brake of the twowheeler. The effect of speed and braking cycles on the torque and thermal behavior of drum brake is studied. The torque required for approximately the same deceleration is dependent on the speed of drum and brake cycles. Similarly, results are found for thermal analysis, and drum surface temperature depends on the speed of the drum. Moreover, the drum surface temperature increases steadily with the increase of brake cycles.

Propagation of Ao Mode through the Front Edge of a Delamination: Numerical and Experimental Studies

Rakesh Kumar Singh,Ramadas Chennamsetti 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

Numerical and experimental studies carried out on the propagation of ultrasonic Lamb wave and its interaction with the front edgeof a delamination in a cross-ply and unidirectional composite laminates are presented in this paper. When the fundamental antisymmetricLamb mode (Ao) is incident at the leading (front) edge of a delamination, it undergoes reflection and transmission into thesub-laminates. Numerical simulations carried out on the interaction of the Ao mode with the edge of a semi-infinite delaminationrevealed that during this interaction, So mode is generated and propagate as AoSo (propagation of the So mode due to the incidentAo mode) mode in the top and bottom sub-laminates along with the incident Ao mode, which propagates as AoAo (propagation of theAo mode due to the incident Ao mode) mode. Transmission factors and power transmission coefficients of AoAo and AoSo modes onan assortment of excitation frequencies – 150 kHz, 175 kHz, 200 kHz and 225 kHz, and thickness ratios were computed. Experimentalvalidation of results arrived through numerical simulations, was also carried out employing air-coupled ultrasonic transducers.

Analysis of Various COVID-19 Prediction Techniques

Rakesh Kumar Arora,Manoj Kumar Gupta,Bhoopesh Singh Bhati 대한전자공학회 2021 IEIE Transactions on Smart Processing & Computing Vol.10 No.4

There is no precise treatment available for COVID-19, but treatment of a number of signs/symptoms is possible. This treatment is provided in accordance with the clinical position of the patient. Furthermore, supplementary care is proven as efficient for infected people. COVID-19 prediction techniques follow various steps, which include dataset collection, pre-processing, feature extraction, and classification. Numerous COVID-19 prediction techniques have been proposed in the literature. In this paper, various techniques are systematically reviewed on the basis outcomes, advantages, and disadvantages.

Magneto-transport Properties of La_(0.80)Sr_(0.20)Mn_(1−x)Cu_xO_3 Thin Films Fabricated by Using Spray Pyrolysis

Pawan Kumar,Rakesh Kumar Dwivedi,Pawan Kumar,Ravikant Prasad,Praveen Kumar Siwach,Hari Krishna Singh 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.1

Thin films of La_(0.80)Sr_(0.20)Mn_(1−x)Cu_xO_3 with x = 0.00, 0.04, 0.08, 0.10, 0.15, and 0.20 were deposited on single-crystal LaAlO_3 (100) (LAO) substrates at 250 ± 10 ℃ by using a nebulized spray pyrolysis technique. Structural, surface, and transport characterizations were done by X-ray diffraction (XRD), atomic force microscopy (AFM) and the standard four probe technique, respectively. XRD patterns revealed the formation of single-phase polycrystalline films with a rhombohedral crystal structure. Cu substitution resulted in a uniform decrease in the metal insulator transition (T_(IM)) temperature up to x = 0.10, followed by a drastic decrease in T_(IM) for x = 0.15. Finally, the metal-insulator transition vanished for higher Cu concentrations (x = 0.20) in the observed temperature range. The variation in T_(IM) with the amount of added Cu is explained on the basis of the double exchange mechanism. Cu substitution has been found to perturb the Mn^(3+)-O-Mn^(4+) network and has a strong influence on T_(IM). The variation in resistivity maxima with temperature for different Cu concentrations showed a systematic trend up to x ∼ 0.10. We also explored the electrical conduction at T > T_(IM) in the framework of small polaron hopping in the adiabatic limit. The activation energy showed a strong dependence on the Cu concentration. The maximum magneto-resistance (MR) up to 10%, was observed for x = 0.15 at low temperatures.

Anomalous Weak Ferromagnetism in Electron-doped Nd_(1−x)Sr_xMnO_3 (0.50 ≤ x ≤ 0.62) Thin Films

Pawan Kumar,Ravikant Prasad,Hari Krishna Singh,Rakesh Kumar Dwivedi,Avanish Kumar Srivastava,Mangala Prasad Singh 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.4

In the present work we demonstrate that an anomalous weak ferromagnetism occurs in the composition range 0.50 ≤ x ≤ 0.62 in nanostructured thin films of Nd_(1−x)Sr_xMnO_3 (NSMO). Nanocrystalline thin films of overdoped manganite Nd_(1−x)Sr_xMnO_3 (<I>x</I> ∼ 0.50, 0.55, 0.60 and 0.62) on single crystal LaAlO_3 (001) substrates are grown by nebulized chemical spray pyrolysis technique. These single phase films possess average crystallite size ∼15 nm and the width of the grain boundaries is ∼1 - 2 nm. In the composition range 0.50 ≤ x ≤ 0.62, the ground state of NSMO is A-type antiferromagnetic (AFM) metallic. However, in the present films a broad paramagnetic (PM) to ferromagnetic (FM) transition is observed in all the compositions at T_C ∼ 226 K for x = 0.50 and 235 K for rest of the samples. All the films show a well-defined M-H hysteresis loop at 5 K. The coercivity (H_C) of these films is much larger than those having composition range 0.35 < x < 0.45. For x = 0.50 (0.62) film H_C = -1210 (-1484) Oe and +1162 (+1476) Oe. The asymmetry in coercivity suggests the presence of weak exchange bias effect in these films. It is observed that the FM ground state in these films have smaller magnetic moment per Mn atom than the expected full moment using the rigid model, we term this as a weak ferromagnetic (WFM) state arising due to the destabilization of the AFM ordering. We propose a possible scenario based on the combined effect of spin reorganization and enhanced orbital disordering in nanosized manganites, to explain the observed anomalous weak ferromagnetism in the A-type AFM spin ordered regime.

In silico ADMET, molecular docking and molecular simulation-based study of glabridin’s natural and semisynthetic derivatives as potential tyrosinase inhibitors

Arti Kumari,Rakesh kumar,Gira Sulabh,Pratishtha Singh,Jainendra Kumar,Vijay Kumar Singh,Krishna Kumar Ojha 경희대학교 융합한의과학연구소 2023 Oriental Pharmacy and Experimental Medicine Vol.23 No.3

Hyper-pigmentation conditions may develop due to erroneous melanogenesis cascade which leads to excess melanin production. Recently, inhibition of tyrosinase is the main focus of investigation as it majorly contributes to melanin production. This inhibition property can be exploited in medicine, agriculture, and in cosmetics. Present study aims to find a natural and safe alternative molecule as tyrosinase inhibitor. In this study, human tyrosinase enzyme was modelled due to unavailability of its crystal structure to look into the degree of efficacy of glabridin and its 15 derivatives as tyrosinase inhibitor. Docking was performed by Autodock Vina at the catalytic core enzyme. Glabridin effects on melanoma cell lines was also elucidated by analysing cytotoxicity and effect on melanin production. Computational ADME analysis was done by SwissADME. Molecular dynamic simulation was also performed to further evaluate the interaction profile of these molecules and kojic acid (positive inhibitor) with respect to apo protein. Notably, four derivatives 5′-formylglabridin, glabridin dimer, 5′-prenyl glabridin and R-glabridin exhibited better binding affinity than glabridin. Glabridin effectively inhibited melanin production in a dose dependent manner. Among these, 5′-formylglabridin displayed highest binding affinity with docking score − 9.2 kcal/mol. Molecular properties and bioactivity analysis by Molinspiration web server and by SwissADME also presented these molecules as potential drug candidates. The study explores the understanding for the development of suitable tyrosinase inhibitor/s for the prevention of hyperpigmentation. However, a detailed in vivo study is required for glabridin derivatives to suggest these molecules as anti-melanogenic compound.

Design, Synthesis, In Silico Screening, and Antiproliferative Activity of Novel 1,2,3-Triazole Tethered Dibenzosuberane Conjugates

Ravi Kant,Keshav Kumar Saini,Ravindra Kumar Upadhyay,Yogender Singh,Y. Veera Manohara Reddy,Shishu Pal Singh,M. Abdul Kareem,K. R. Dasegowda,H. Prabhavati,Rakesh Kumar,박종필,Lalita S. Kumar 한국생물공학회 2023 Biotechnology and Bioprocess Engineering Vol.28 No.5

To explore novel and potent compounds with anticancer activity, two series of 1H-1,2,3-triazole tethered dibenzosuberane conjugates (5a-i and 5j-n) were synthesized using a linear and convergent approach. The synthesized novel compounds were screened for their in vitro antiproliferative activity against HepG2 cell lines using the MTT assay to explore their binding interactions with the 5EQG protein. IC50 values revealed that the most active combination against HepG2 cell lines was triazole tethered with an ortho chloro-substituted aryl ring (5g) (IC50: 99.64 μg/mL). The other compounds in the series exhibited comparable cytotoxic activities against HepG2 cell lines. The results were substantiated by molecular docking studies. The majority of the compounds demonstrated high binding affinity for the active site of the targeted protein. In addition, in silico drug-likeness prediction by the ADMET method has been explored with these compounds. All synthesized novel derivatives were characterized by mass spectrometry, infrared spectroscopy, 1H-nuclear magnetic resonance (NMR) spectroscopy, and 13C-NMR spectroscopy.

Complete Bony Segment Flap Failure without Skin Paddle Compromise in Fibular Free Flap: A Case Report of a Rare Early Complication

Singh Hardeep,Jain Ankit,Jain Rahul,Mahendru Sanjay,Khazanchi Rakesh Kumar 대한창상학회 2023 Journal of Wound Management and Research Vol.19 No.1

The free fibula flap is sometimes associated with partial flap loss. A 62-year-old man with squamous carcinoma of the lower alveolus underwent anterior arch resection and reconstruction with a fibula osteocutaneous flap containing three bony segments. There were two perforators in the skin flap; the first perforator was proximal to the bony segments and the other perforator was at the level of the middle segment. Atherosclerosis was observed in the anastomotic vessels. During surgery, thrombosis occurred in the arterial anastomosis, but was revised before the operation was over. The patient’s early postoperative course was uneventful. In the second week, purulent discharge was observed from the drains. Flap exploration showed devascularization of bony segments and periosteum, but the skin paddle was viable. The peroneal vessel had thrombosed distal to the takeoff of the proximal perforator and the viable skin paddle perfused by proximal perforators falsely indicated the well-being of underlying bones. The de-vascularized bones and sloughed periosteum were removed at the time of exploration, after which the skin paddle was reoriented for coverage of the defect. The patient completed chemoradiation without any bony reconstruction afterwards. This is the only reported case of early total bony flap portion loss with a viable skin paddle in free fibula flap transfer.