• 대한수학회논문집
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• 제37권3호
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• pp.705-718
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• 2022

In this paper, for bounded linear operators A, B, C satisfying [AB, B] = [BC, B] = [AB, BC] = 0 we study the Drazin invertibility of the sum of products formed by the three operators A, B and C. In particular, we give an explicit representation of the anti-commutator {A, B} = AB + BA. Also we give some conditions for which the sum A + C is Drazin invertible.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3164-3170
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• 2021

The increasing interest that GEANT4 is gaining nowadays, because of its special capabilities, prompted us to address its reliability in neutronic calculation for the realistic and complex spallation target MEGAPIE of the Paul Scherrer Institute of Switzerland. In this paper we have specifically addressed the neutronic characterization of the active zone of this target. Three physical quantities are evaluated: neutron flux spectra and total neutron fluxes on target's z-axis, and the neutron yield as a function of the target's altitude and radius. Comparison of the obtained results with those of the MCNPX reference code and some experimental measurements have confirmed the impact of the geometrical and proton beam models on the neutron fluxes. It has also allowed to reveal the intrinsic influence of the code type. The resulting differences reach a factor of ~2 for the beam model and 4-18% for the other parameters cumulated. The analysis of the neutron yield has led us to conclude that: 1) Increasing the productivity of the MEGAPIE target cannot be achieved simply by increasing the thickness of the target, if the irradiation parameters are not modified. 2) The size of the spallation area needs to be redefined more precisely.

• Molecules and Cells
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• 제45권12호
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• pp.883-885
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• 2022

• 대한수학회논문집
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• 제35권2호
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• pp.455-468
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• 2020

An element in a ring R with identity is called invo-clean if it is the sum of an idempotent and an involution and R is called invoclean if every element of R is invo-clean. Let C(R) be the center of a ring R and g(x) be a fixed polynomial in C(R)[x]. We introduce the new notion of g(x)-invo clean. R is called g(x)-invo if every element in R is a sum of an involution and a root of g(x). In this paper, we investigate many properties and examples of g(x)-invo clean rings. Moreover, we characterize invo-clean as g(x)-invo clean rings where g(x) = (x-a)(x-b), a, b ∈ C(R) and b - a ∈ Inv(R). Finally, some classes of g(x)-invo clean rings are discussed.

• Journal of Information Technology Applications and Management
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• 제19권3호
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• pp.1-18
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• 2012

The present study highlights the conflict management levels in Indian manufacturing and Information Technology (IT) sectors. Nearly 110 samples from different organizations of manufacturing and IT have been collected using convenient sampling technique. Standardised scale on Organisational Conflict developed by Dhar U. and Dhar S. [2003] has been used which consists of twenty items on a four point scale. The study has shown that miscommunication at organizational level has been a reason for conflict in manufacturing organizations whereas intrinsic motivation at organizational as well as individual level has been found a reason for conflict in IT sector. The study bears implications for HR managers to develop policies and conflict management strategies so as to deal with the situations constructively at a particular level of conflict.

• 대한수학회논문집
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• 제33권1호
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• pp.157-164
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• 2018

A $C_0$-semigroup ${\tau}=(T_t)_{t{\geq}0}$ on a Banach space X is called subspace-supercyclic for a subspace M, if $\mathbb{C}Orb({\tau},x){\bigcap}M=\{{\lambda}T_tx\;:\;{\lambda}{\in}\mathbb{C},\;t{\geq}0\}{\bigcap}M$ is dense in M for a vector $x{\in}M$. In this paper we characterize the notion of subspace-supercyclic $C_0$-semigroup. At the same time, we also provide a subspace-supercyclicity criterion $C_0$-semigroup and offer two equivalent conditions of this criterion.

• 대한수학회보
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• 제56권5호
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• pp.1219-1233
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• 2019

Let $E{\rightarrow}M$ be an arbitrary vector bundle of rank k over a Riemannian manifold M equipped with a fiber metric and a compatible connection $D^E$. R. Albuquerque constructed a general class of (two-weights) spherically symmetric metrics on E. In this paper, we give a characterization of locally symmetric spherically symmetric metrics on E in the case when $D^E$ is flat. We study also the Einstein property on E proving, among other results, that if $k{\geq}2$ and the base manifold is Einstein with positive constant scalar curvature, then there is a 1-parameter family of Einstein spherically symmetric metrics on E, which are not Ricci-flat.

• 한국초지학회:학술대회논문집
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• 한국초지조사료학회 2002년도 제27회 정기총회, 제40회 학술발표회
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• pp.19.1-19
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• 2002

• Nutrition Research and Practice
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• 제12권6호
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• pp.535-540
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• 2018

BACKGROUND/OBJECTIVES: Propolis has a rich source of bioactive compounds and has renal and hepatic protective properties. The purpose of this study was to investigate the beneficial effect of hydro-ethanolic extract of propolis against paracetamol-induced liver damage and impairment of kidney function, as well as hematological changes in rats. MATERIALS/METHODS: Six groups of rats were used; the first group was served as a control; the second and third groups were treated by propolis extract at a dose of 50 and 100 mg/kg.B.WT. respectively; the fourth group was treated by paracetamol (200 mg/kg.B.WT.); the fifth group was treated by propolis (50 mg/kg.B.WT.) for eight days and then received similar dose of propolis for following seven days with paracetamol at a dose of 200 mg/kg.B.WT. daily for the seven days; and the sixth group was treated with propolis (100 mg/kg.B.WT.) for eight days and then received similar dose of propolis for following seven days with paracetamol at a dose of 200 mg/kg.B.WT. daily for the seven days. All the animals were treated for a period of 15 days. At the end of the experimental period, blood samples were collected for measurement of the liver enzymes, serum albumin, protein and creatinine, blood urea nitrogen, hematological parameters, and urine volume, protein and albumin. RESULTS: Paracetamol over dose significantly lowered hemoglobin, serum total protein, albumin, and uric acid, while it significantly increased blood creatinine, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase activities, white blood cells, and platelet count as compared to the control. However, these alterations were significantly attenuated by the use of propolis extract and the effect was dose dependent. Interestingly, propolis prevented paracetamol induced proteinuria, low hemoglobin and body weight loss. CONCLUSIONS: Propolis significantly prevented paracetamol induced renal, hepatic and hematological toxicity and might be useful in the management of liver and renal diseases particularly proteinuria.

• Journal of Plant Biology
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• 제38권1호
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• pp.47-54
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• 1995

본 연구는 $H_2O_2$ 축적이 수반되는 잎의 노쇠현상과 관련하여 세포질내 ascorbate-glutathione 회로의 역할 가능성과 이때 benzyladenine(BA)의 효과를 밝히기 위하여 노쇠중인 밀 잎에서 시토졸 ascorbate peroxidase(APX) isozyme 분리 및 발달양상과 ascorbate-glutathione 회로 구성효소들의 활성도 변화를 조사하였다. 성숙한 밀 제1엽 절편을 4일간 암배양하는 동안 증가된 엽록소 분해 및 $H_2O_2$ 축적으로 규정되는 잎의 노쇠발달중 대조구 잎에서는 시토졸 APX 활성도의 유의성 있는 증가가 관찰되지 않았으며 dehydroascorbate reductase(DHAR)의 활성도는 급격히 감소되었고, glutathione reductase(GR) 활성도는 완만하게 증가하였다. 그러나 BA로 처리된 잎에서는 시토졸 APX 활성도가 현저하게 증가하였으며 DHAR 활성도의 감소가 지연되어 나타났고 GR 활성도의 증가는 대조구에 비해 증진되었으며 내재성 ascorbate 함량의 감소율과 H2O2 축적이 억제되었다. 3개의 시토졸 APX isozyme이 native-PAGE법에 의해 노쇠중인 밀 잎에서 발견되었으며 그 중 2개 isozyme은 높은 활성도를 보였다. 시토졸 APX isozyme의 발달양상의 경우 4일간의 암배양 동안 대조구 잎에서는 단지 2개의 isozyme band("a"와 "b")가 거의 같은 활성도를 지닌 채 출현하였으나 BA로 처리된 잎에서는 추가로 1개의 약한 isozyme band("c")가 더 나타났으며 "b" isozyme의 활성도가 약간 촉진되었다 그러나 "a" isozyme 활성도는 대조구 잎에 비해 암배양시간 경과에 따라 현저하게 발달하였다. 대조구 잎과 비교시 BA로 처리된 잎에서는 시토졸 APX isozyme의 발달 및 APX, DHAR, GR의 전체 활성도가 함께 증진되어 그 결과 $H_2O_2$ 제거능력이 증대된 본 실험의 결과는 ascorbate-glutathione 회로가 밀 잎의 노쇠과정에 중요하게 작용하고 있음을 제시하였다.