Receipt of lump-sum distributions from retirement plans

Gupta, Shamlall University of Minnesota 1993 해외박사

Digital X-ray Source Based on Carbon Nanotube Field Emitters; a Paradigm Shift in Medical X-ray Technology

GUPTA AMAR PRASAD 경희대학교 대학원 2023 국내박사

The art of Physics is understanding the phenomena and offering the new inventions to a real world problem. Continuously, driven by the question of HOW, WHY AND WHAT, the modern day Physicists do not just sit down and solves the equations of universe on paper, rather they raise from the chair and strive to invent things better than engineers could. This dissertation complies the series of works that offers and alternative solution to conventional X-ray source, which is more efficient, novel and well-suited with this generation of time. Since X-rays were discovered more than a century ago, most of the engineering techniques used to make X-ray sources haven't changed much. There haven't been many important technological improvements since the invention of thermionic electron sources, which are still utilized in practically all X-ray applications due to their ease of fabrication. However, nanomaterials and their efficient ways of fabrication have made it possible to replace traditional thermionic devices with cold cathode electron sources (field electron emission). The thermionic process of electron emission is inefficient because of the lagging time between heating up the filament and producing electrons. Thus, the filament-based thermionic emission is called analogue as the perfect pulses of electrons cannot be generated. Nanomaterials such as CNTs, composites of CNTs with other elements, metal tips, graphene, nanodiamond, silicon tips or any other nanostructure with high aspect ratio can be utilized to make cold cathode X-ray source based on field electron emission (FEE) process. In field emission-based cold cathode X-ray source, free electrons are usually extracted from the tips of nanostructure (cathode) inside a vacuum due to localized high electric field produced by an external voltage from gate or extractor. Because of the voltage dependence of the FEE process, the X-ray source can be digitalized with perfect pulses while using less power than filament-based X-ray sources. The smaller, lighter X-ray machines can be built with the digitalized X-ray system, which also emits less radiation. The fact that digital X-ray sources have rapid response times and precise radiation dose pulses is one of their most crucial features. Additionally, digital X-ray sources based on nanomaterials offer a significant opportunity for the effective integration of distributed X-ray sources into a single system. For these above reasons, researchers and engineers from all around the world are looking for a stable cold cathode electron emitter that can replace the hot filament inside the X-ray source. The work in my dissertation tries to find a way to connect the making and optimizing of X-ray source based on Carbon Nanotubes for high-speed radiographic imaging, especially with the goal of transforming the medical X-ray technology. This dissertation research includes the growth of carbon nanotubes on metal substrate for easier and economic way to mass produce the electron emitters. It also shades light on how metal substrate will advent the race of 3D field emitter. Using these field emitters and filament, open-type and closed type X-ray tubes are fabricated for medical purposes. Finally, I summarize this work's findings and outline the subsequent actions that will be taken to build the foundation for a new paradigm of X-ray source.

Exploring the role of hypoxia and propyl hydroxylases in modulating type 2 immunity

Gupta, Anupriya 한림대학교 대학원 2023 국내박사

Type 2 inflammation is a key component of various allergic and inflammatory diseases, including atopic dermatitis (AD) and asthma. AD is a chronic inflammatory skin disease characterized by eczema and itching. The dysregulation of immune responses and altered cellular metabolism play key roles in AD pathogenesis. The mechanistic target of rapamycin complex (mTORC) signaling pathway has recently emerged as a critical regulator of immune responses and a potential target for immunomodulatory therapies. Additionally, the impact of environmental factors, including hypoxia, on AD development remains poorly understood, especially in relation to type 2 inflammation. Using a mouse model of MC903-induced AD-like skin inflammation, we investigated the role of mTORC signaling in AD pathogenesis. Activation of mTORC1, evidenced by the phosphorylation of ribosomal protein S6, was observed upon MC903 treatment. Interestingly, we found dual roles of mTORC1 in regulating type 2 inflammation in AD. Raptor-deficient mice displayed significantly reduced skin inflammation, accompanied by decreased eosinophil recruitment and IL-4 production, suggesting that mTORC1 promotes type 2 immunity and contributes to the pro-inflammatory cascade in AD. Furthermore, we explored the impact of hypoxia and its regulatory mechanisms on AD. Inhibiting prolyl hydroxylase (PHD), an enzyme that stabilizes hypoxia-inducible factor (HIF), using the inhibitor DMOG, attenuated MC903-induced AD-like symptoms. Intriguingly, PHD inhibition led to the downregulation of key mediators of type 2 inflammation, including thymic stromal lymphopoietin (TSLP) and interleukin-33 (IL-33), through the reactive oxygen species (ROS) pathway. These findings suggest that targeting PHD and modulating HIF signaling may provide a novel therapeutic approach for alleviating type 2 inflammation in AD. In conclusion, this study highlights the intricate relationship between mTORC signaling, hypoxia-inducible factor (HIF) regulation, and type 2 inflammation in AD. We demonstrate that mTORC1 promotes type 2 immunity, while inhibiting PHD and suppressing HIF signaling attenuate AD-like symptoms and downregulate type 2 cytokines. These findings shed light on the complex molecular mechanisms underlying AD pathogenesis and offer potential targets for future therapeutic interventions to modulate type 2 inflammation in AD. Further investigations into these pathways are warranted to fully understand their clinical implications and therapeutic potential. 제2형 염증은 아토피 피부염(AD)과 천식을 포함한 다양한 알레르기 및 염증성 질환의 핵심 요소입니다. 아토피 피부염은 습진과 가려움증을 특징으로 하는 만성 염증성 피부 질환입니다. 면역 반응의 조절 장애와 세포 대사의 변화는 AD 발병에 중요한 역할을 합니다. 라파마이신 복합체(mTORC) 신호 전달 경로의 기계적 표적은 최근 면역 반응의 중요한 조절자이자 면역 조절 치료의 잠재적 표적으로 부상하고 있습니다. 또한 저산소증을 포함한 환경 요인이 AD 발병에 미치는 영향은 특히 2형 염증과 관련하여 아직 제대로 이해되지 않고 있습니다. MC903으로 유도된 AD 유사 피부 염증의 마우스 모델을 사용하여 AD 발병에서 mTORC 신호의 역할을 조사했습니다. MC903 처리 시 리보솜 단백질 S6의 인산화에 의해 입증된 mTORC1의 활성화가 관찰되었습니다. 흥미롭게도 알츠하이머병의 2형 염증을 조절하는 데 있어 mTORC1의 이중 역할이 발견되었습니다. 랩터가 결핍된 마우스는 호산구 모집 및 IL-4 생산 감소와 함께 피부 염증이 현저히 감소한 것으로 나타났는데, 이는 mTORC1이 제2형 면역을 촉진하고 AD에서 염증성 캐스케이드에 기여한다는 것을 시사합니다. 또한 저산소증과 그 조절 메커니즘이 알츠하이머병에 미치는 영향을 탐구했습니다. 저산소증 유도 인자(HIF)를 안정화시키는 효소인 프롤릴 하이드 록실라제(PHD)를 억제제 DMOG를 사용하여 억제하면 MC903에 의해 유발된 AD 유사 증상이 약화되었습니다. 흥미롭게도 PHD를 억제하면 활성 산소 종(ROS) 경로를 통해 흉선 간질 림포포이에틴(TSLP)과 인터루킨-33(IL-33)을 포함한 제2형 염증의 주요 매개체가 하향 조절되었습니다. 이러한 연구 결과는 PHD를 표적으로 삼고 HIF 신호를 조절하는 것이 알츠하이머병의 2형 염증을 완화하는 새로운 치료 접근법을 제공할 수 있음을 시사합니다. 결론적으로, 이 연구는 알츠하이머병에서 mTORC 신호, 저산소증 유도 인자(HIF) 조절 및 제2형 염증 사이의 복잡한 관계를 강조합니다. 우리는 mTORC1이 제2형 면역을 촉진하는 반면, PHD를 억제하고 HIF 신호를 억제하면 AD 유사 증상이 약화되고 제2형 사이토카인이 하향 조절된다는 사실을 입증했습니다. 이러한 연구 결과는 알츠하이머병 발병의 기저에 있는 복잡한 분자 메커니즘을 밝히고 알츠하이머병의 2형 염증을 조절하기 위한 향후 치료적 개입의 잠재적 표적을 제공합니다. 이러한 경로의 임상적 의미와 치료 잠재력을 완전히 이해하기 위해서는 이러한 경로에 대한 추가 조사가 필요합니다.

Application of Photoactive Diruthenium Catalyst for New Organic Reactions: Syntheses of Imines, Isoquinolines, and Vinylstannanes

Gupta, Sreya POSTECH 2014 국내박사

Light had the potential to serve as an inexpensive, abundant, renewable, and nonpolluting reagent for chemical transformations. Thus developing new methodologies by employing metal-catalyst activated by visible light is the pivotal interest in the field of organic synthesis. In this thesis, we investigated important chemical transformation catalyzed by carbonyl bridged diruthenium complexes which is activated by visible light source. In chapter 1, Ru-catalyzed synthesis of N-unsubstituted imines from easily available alkyle azides under the photolytic condition has described. N-unsubstituted imines were generated by removal of N2 gas from azide precursors and subsequent migration of hydrogen atom under the house hold fluorescent light. This novel protocol has shown broad synthetic scope to construct various N-unprotected imines including unprecedented enolizable substrates. Mild reaction conditions used in this protocol even allowed obtaining fundamental physical parameters of N-unprotected imines, such as, existence of dynamic geometric isomers in the solution phase and dissociation energy of imino N-H bond. This novel synthetic route was successfully applied in one-pot imine generation/allylation sequence by using allylboron reagents; directly N-unprotected allylamines were formed without any undesirable side reactions. The above one-pot sequence has shown greater efficiency over prevailing methodologies in terms of enantio- and diastereoselectivity. Furthermore, this protocol also effective to synthesize N-unsubstituted imidates from various azidoethers. This is the first report of imidate synthesis in neutral reaction conditions which allowed constructing imidates having acid-labile functionality. Chapter 2 describes the Ru/Rh-tandem catalysis to synthesize isoquinoline from arylazides and internal alkynes by direct C-H bond activation. N-unsubstituted arylimines generated from the corresponding azides by the ruthenium catalysis were used as a directing group for rhodium-catalyst to activate the C-H bond at ortho-position of aromatic ring. Subsequent addition of various internal alkynes produces N-annulated isoquinolines. The essential merits of this cascade protocol are broad scope of applicable benzylic azides, including those having carbonyl and chiral functionalities. Additionally, this protocol is completely atom-economical as N2-gas is the only the byproduct. Furthermore, N-unsubstituted imidate synthesized by Ru-catalyst II from the corresponding azidoethers, also turned out to be the successful entity for direct synthesis of 1-alkoxyisoquinolines. The mechanism of the above transformation was established through the isolation and characterization (X-ray crystallography structure) of the important unknown intermediates. Previously we reported the hydrosilylation of aldehydes1 by using ruthenium catalyst under fluorescent light condition. We expected this catalyst can activate other metal-hydride species too. In the chapter 3, ruthenium-catalyzed addition of tin hydride to various internal alkynes (hydrostannation) under fluorescent light was described. The reaction was initiated by the formation of ruthenium hydride and tin radical species under the illumination of light. In the termination step, tin-radical and the hydrogen from ruthenium hydride species were added to the alkynes in anti-stereoselective way. In general, control the regio- and setreoselectivity of hydrostannation reaction is the formidable challenge. However, in above ruthenium photocatalyzed system, (Z)-β-selective vinylstannanes were obtained selectively for various internal alkynes and shown better activity over well-known radical initiators such as AIBN (azobisisobutyronitril) or BEt3 (triethylborane). To obtain insight into the hydrostannation mechanism, we conducted various experiments. The outcome of various control experiments strongly suggested the insolvent of radical mechanism and the formation of ruthenium-hydride (VI) as a key intermediate species under the fluorescent light. Additionally, the recyclability of the ruthenium catalyst added extra advantage of this novel methodology. 1 Do, Y.; Han, J.; Rhee, Y. H.; Park. J. Adv. Synth. Catal. 2011, 353, 3363.

KOREAN FDI ININDIA : AN ASSESSMENT OF PERFORMANCE AND CHALLENGES

Gupta, Dhiraj Kumar Graduate school of international studies, Korea un 2009 국내석사

India's increasing openness to FDI, especially after the New Industrial Policy in 1991, has contributed importantly to its exceptional growth performance. The paper examines the Korean?s FDI in India experience with FDI since 1991 and looks for the way to promote the FDI inflows in India, from Korean perspectives. Since the New Industrial Policy in 1991, Korean companies also increased FDI in India and formed joint ventures with Indian companies or Greenfield investment in automobiles, consumer goods industry and so on. With the case study of Samsung, LG, Hyundai and POSCO, we could understand that industrial clusters are pl aying an important role in economic activity. This is particularly true in technology intensive industries like IT, automobiles, electronics etc. Further detailed empirical studies on FDI with industrial clusters are necessary to understand more about the spillovers of FDI in India.

New freedoms, new dependencies : new reproductive technologies, women's health and autonomy

Gupta, Jyotsna Agnihotri Rijksuniversiteit te Leiden 1996 국내박사

A study of cavities and waveguides containing anisotropic media

Gupta, Radha R University Microfilms International 1965 국내박사

Effekte der nicht-depolarisierenden Muskelrelaxanzien Pancuronium, Vecuronium, Pipecuronium und Atracurium auf den Katecholaminhaushalt des Ventrikelmyokards

Gupta, Robin Sen Universit¨at Hamburg 1997 국내박사

Gut-Liver axis in patients with alcoholic liver disease : modulation of microbiota and natural killer cell

Gupta, Haripriya 한림대학교 2020 국내박사

The current study provides a description of the compositional changes associated with ALD and changes in metagenomics and immunomodulatory functions of gut microbiome in relation with probiotics. Alcohol intake is the preliminary and important driving factor for dysbiosis in patients with ALD. Our study indicated that increase and decrease in relative abundance of phylum Proteobacteria and Bacteroidetes, respectively, is the driving culprit for the progression of ALD leading to SIBO and disrupting the harmonious balanced relationship between gut microbiome. Butyrate producing bacterial families, Ruminococcaceae and Lachnospiraceae from class Clostridiales were more enriched in HNC and HAC compared with AH & ASH and AC suggesting disruption of gut barrier integrity leading to bacterial endotoxins translocation in systemic circulation and activation of proinflammatory and immune response. On contrary to this, relative overgrowth of pathogenic family Enterobacteriaceae, Lactobacillaceae, Streptococcaceae and Staphylococcaceae were associated with progression of ALD. This result was consistent with the studies demonstrated by Bajaj et al showing a change towards pathogenic bacterial community in advancement of ALD as described previously. As a novel finding from this study, Christensenellaceae, another butyrate-producing bacteria shown to be decreased significantly in ALD patients. While another study provided evidence that supplementation with sodium butyrate enriched this beneficial bacteria in high fat diet induced non-alcoholic fatty liver disease. Seven-day of supplementation with Lactobacillus rhamnosus R0011 and Lactobacillus acidophilus R0052 was associated with restoration of gut microbiome and probiotics might be effective in the treatment of alcoholic hepatitis by regulation gut-liver axis. PCR-DGGE analysis indicates probiotic modulation in E. coli and Enterobacteria showing decrease band density while increased Ruminococcaceae and Bacteroidetes band density. Metagenomics study demonstrated significant enrichment in Ruminococcaceae, Lachnospiraceae, Prevotellaceae and Christensenellaceae and decrease in relative abundance was observe in order Pseudomonadales from phylum Proteobacteria. Moreover, an increase in Fusobacteria in large amount of alcohol consuming population was observe[7, 9] was in accordance with placebo group from our study and was found to be decreased after probiotics treatment. These finding supporting the notion that probiotic are potentially strong candidate for therapeutic treatment for patients with ALD. In addition to that, it was evident from our experiment that cytotoxic cell population of NK cell was decreased in patients with AH & ASH and AC. Relating NK cell function with microbiome suggests decrease in beneficial microbiome has shown to decrease cytotoxic function of NK cells. Decrease in cytotoxic population of NK despite an overall NK cell population in circulation was indication of inhibitory responses promoting disease progression in ALD patients. For future point of view, we still need further studies to better understand the physiological and pathophysiological functions and mechanism of microbiome in this study since we had small no. of analyzed patients stool samples in probiotic treatment and short-term administration only. Also the mechanism associated with immunomodulatory function of probiotics in human need to be further explored.

Aggregation issues in product costing

Gupta, Mahendra R Stanford University 1990 해외박사