Numerical Investigation on Gas Bubbling Assisted Inclusion Transport and Removal in Multistrand Tundish

Vipul Kumar Gupta,Pradeep Kumar Jha,Pramod Kumar Jain 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

In continuous casting, the molten metal quality in the mold is affected by flow pattern, temperature distribution and inclusiontransport in the multistrand tundish. Natural convection due to thermal buoyancy directly influences these parameters andwith gas bubbling, further improvisation can be made. In the present work, numerical investigation of the effect of thermalbuoyancy is carried out to examine the flow field, temperature distribution and inclusion trajectories. Further, gas bubblingcurtain modeling using the Euler-Euler approach is performed for the different locations on the bottom wall of the tundishand quantitative analysis of tundish performance is presented using residence time distribution (RTD) curves. The resultsshow that big circulation loop generated due to thermal buoyancy assists in inclusion removal and mixing at each outlet. Gas bubbling increases the molten metal flow velocity in the central region of tundish, leading to a decrease in the dimensionlessnumber Gr/Re2 near the outlets which are far away from the inlet of the tundish i.e. outlet 2 and outlet 3. Hence, thedominance of natural convection decreases. The inclusion removal rate is found to increase significantly as the circulationloop formed at each side of the curtain forces them upward direction. However, the reported inclusion removal rate in gasbubbling cases is found to be independent of particle size and curtain location.

Delayed diagnosis of bronchobiliary fistula complicating a pediatric living donor liver transplantation: a case report

Vipul Gautam,Vikram Kumar,Shaleen Agarwal,Subhash Gupta 대한이식학회 2023 Korean Journal of Transplantation Vol.37 No.4

Bronchobiliary fistula (BBF) is a very rare condition in children. Only a few pediatric BBF cases have been reported, in the context of a ruptured hydatid cyst or liver abscess. BBF after living donor liver transplantation (LDLT) has not been reported in the pediatric literature. We report a 7-year-old female child with Wilson disease, who developed BBF post-LDLT. She had a clinically uneventful course in the immediate post-transplant period. She was readmitted on postoperative day (POD) 75 with a productive cough and respiratory difficulty, which was diagnosed as bilioptysis secondary to BBF. Endoscopic retrograde cholangiopancreaticography was attempted but failed. Exploratory laparotomy showed a fistula from the strictured biliary anastomotic site to the right thoracic cavity; it was excised, and a Roux-en-Y hepaticojejunostomy was performed. She tolerated the procedure well and remained clinically well on follow-up through POD 185. BBF is extremely rare in children. This is the first case report of BBF in a child following LDLT. BBF requires a high index of suspicion for a timely intervention to prevent subsequent complications.

Exploring the Potential of Natural Products as FoxO1 Inhibitors: an In Silico Approach

Gupta Anugya,Haldhar Rajesh,Agarwal Vipul,Rajput Dharmendra Singh,Chun Kyung-Soo,Han Sang Beom,Raj Vinit,Lee Sangkil 한국응용약물학회 2024 Biomolecules & Therapeutics(구 응용약물학회지) Vol.32 No.3

FoxO1, a member of the Forkhead transcription factor family subgroup O (FoxO), is expressed in a range of cell types and is crucial for various pathophysiological processes, such as apoptosis and inflammation. While FoxO1’s roles in multiple diseases have been recognized, the target has remained largely unexplored due to the absence of cost-effective and efficient inhibitors. Therefore, there is a need for natural FoxO1 inhibitors with minimal adverse effects. In this study, docking, MMGBSA, and ADMET analyses were performed to identify natural compounds that exhibit strong binding affinity to FoxO1. The top candidates were then subjected to molecular dynamics (MD) simulations. A natural product library was screened for interaction with FoxO1 (PDB ID- 3CO6) using the Glide module of the Schrödinger suite. In silico ADMET profiling was conducted using SwissADME and pkCSM web servers. Binding free energies of the selected compounds were assessed with the Prime-MMGBSA module, while the dynamics of the top hits were analyzed using the Desmond module of the Schrödinger suite. Several natural products demonstrated high docking scores with FoxO1, indicating their potential as FoxO1 inhibitors. Specifically, the docking scores of neochlorogenic acid and fraxin were both below -6.0. These compounds also exhibit favorable drug-like properties, and a 25 ns MD study revealed a stable interaction between fraxin and FoxO1. Our findings highlight the potential of various natural products, particularly fraxin, as effective FoxO1 inhibitors with strong binding affinity, dynamic stability, and suitable ADMET profiles.

Nanoelectronics: Tunneling current in DNA–Single electron transistor

Rakesh K. Gupta,Vipul Saraf 한국물리학회 2009 Current Applied Physics Vol.9 No.11

Modern silicon-integrated circuit technology has been undoubtedly increasing computing speed every 18 to 24 months according to Moor’s prediction and further, reduction in feature dimensions is not possible without various quantum problems. Despite the fabrication of the molecular junctions (acting as quantum dots), and a CNT field-effect transistor, it is very difficult to connect a single molecule to external leads, thus preventing verification of this idea until recently. Individual molecules can perform functions identical to those of the key components of present day microcircuits. Molecular engineering extends its potential application to manufacture electronic devices at nano scale with much more sophisticated advantages over the modern day microelectronics. The reason behind forming molecular electronics may be that the society at large has a demand for smaller, faster, simpler and better technologies. Bioelectronics is one of the areas of interest that overlaps with biotechnology and includes DNA electronics and cellular computing. Electronic circuit components using single molecules have been proposed since 1974. DNA-based electronic components such as single electron transistors are also being proposed and realized. In this paper, we present the possible tunneling current under different external biasing conditions. DNA–SET model is based on tunneling properties of P-bonds (as tunneling junctions in coulomb blockade regime) in sugar–phosphate backbones of single-strand DNA molecules. Modern silicon-integrated circuit technology has been undoubtedly increasing computing speed every 18 to 24 months according to Moor’s prediction and further, reduction in feature dimensions is not possible without various quantum problems. Despite the fabrication of the molecular junctions (acting as quantum dots), and a CNT field-effect transistor, it is very difficult to connect a single molecule to external leads, thus preventing verification of this idea until recently. Individual molecules can perform functions identical to those of the key components of present day microcircuits. Molecular engineering extends its potential application to manufacture electronic devices at nano scale with much more sophisticated advantages over the modern day microelectronics. The reason behind forming molecular electronics may be that the society at large has a demand for smaller, faster, simpler and better technologies. Bioelectronics is one of the areas of interest that overlaps with biotechnology and includes DNA electronics and cellular computing. Electronic circuit components using single molecules have been proposed since 1974. DNA-based electronic components such as single electron transistors are also being proposed and realized. In this paper, we present the possible tunneling current under different external biasing conditions. DNA–SET model is based on tunneling properties of P-bonds (as tunneling junctions in coulomb blockade regime) in sugar–phosphate backbones of single-strand DNA molecules.

REtrospective Multicenter INdian Study of Derivo Embolization Device (REMIND): Periprocedural Safety

Niranjan Prakash Mahajan,Mudasir Mushtaq,Amit Bhatti,Sukalyan Purkayastha,Nitin Dange,Mathew Cherian,Vipul Gupta,Vikram Huded 대한신경중재치료의학회 2021 Neurointervention Vol.16 No.3

Purpose: The treatment of aneurysms with characteristics such as complex morphology, fusiform, blister-like, wide neck, or large size has been revolutionized with the introduction of flow diverters. Though flow diverters have several advantages over coiling, they also have certain important disadvantages such as the lack of immediate protection against rupture, the risk of ischemic stroke, the need for antiplatelet therapy, and long latency for complete effect. The Derivo Embolization Device (DED) is a second-generation self-expanding device that is claimed to be less thrombogenic than conventional devices. We retrospectively evaluated the periprocedural safety and risks associated with the DED across 5 centers in India. Materials and Methods: This is a multicentric, retrospective, observational study of DED, conducted at 5 high volume endovascular therapy centers in India from May 2018 to June 2020. Periprocedural demographic, clinical, and angiographic data were collected from a retrospective review of patient charts. Results: A total of 96 patients, including 56 (58.3%) females, aged between 16–80 years (60±12.7 years) harboring 106 aneurysms were studied. Seven (7.3%) were noted to harbor multiple aneurysms: 6 had 3 aneurysms each, while 1 patient had 5 aneurysms. The following aneurysm characteristics were noted: average size, 9.8±8.2 mm; average neck size, 6.9±8.5 mm; wide-necked (>4 mm), 63 (59.4%); giant (>25 mm), 8 (7.5%); and anterior circulation location, 98 (92.5%). Eighteen (17%) of these were ruptured. Additional balloon angioplasty was performed in 5 (5.2%) patients. Intraprocedural problems were encountered in 3 (3.1%), of which only 1 had clinical implications, the device fish-mouthing with stent thrombosis resulting in a malignant middle cerebral artery territory infarction. The modified Rankin scale at 3 months was worse in 1 patient. Conclusion: DED is a newer generation flow diverter stent with a low periprocedural complication rate.