• International Journal of Oral Biology
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• v.38 no.3
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• pp.111-119
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• 2013

Objective. To investigate the effects of the hypoxia inducible factor-1 (HIF-1) activation-mimicking agent cobalt chloride ($CoCl_2$) on the osteogenic differentiation of human mesenchymal stem cells (hMSCs) and elucidate the underlying molecular mechanisms. Study design. The dose and exposure periods for $CoCl_2$ in hMSCs were optimized by cell viability assays. After confirmation of $CoCl_2$-induced HIF-$1{\alpha}$ and vascular endothelial growth factor expression in these cells by RT-PCR, the effects of temporary preconditioning with $CoCl_2$ on hMSC osteogenic differentiation were evaluated by RT-PCR analysis of osteogenic gene expression, an alkaline phosphatase (ALP) activity assay and by alizarin red S staining. Results. Variable $CoCl_2$ dosages (up to $500{\mu}M$) and exposure times (up to 7 days) on hMSC had little effect on hMSC survival. After $CoCl_2$ treatment of hMSCs at $100{\mu}M$ for 24 or 48 hours, followed by culture in osteogenic differentiating media, several osteogenic markers such as Runx-2, osteocalcin and osteopontin, bone sialoprotein mRNA expression level were found to be up-regulated. Moreover, ALP activity was increased in these treated cells in which an accelerated osteogenic capacity was also verified by alizarin red S staining. Conclusions. The osteogenic differentiation potential of hMSCs could be preserved and even enhanced by $CoCl_2$ treatment.

• The KIPS Transactions:PartA
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• v.10A no.2
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• pp.137-140
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• 2003

Recently, CG (Conjugate Gradient) scheme for the optimization of the Rayleigh quotient has been proven a very attractive and promising technique for interior eigenvalues for the following eigenvalue problem, Ax＝λx (1) The given matrix A is assummed to be large and sparse, and symmetric. Also, the method is very amenable to parallel computations. A proper choice of the preconditioner significantly improves the convergence of the CG scheme. We compare the parallel preconditioners for the computation of the interior eigenvalues of a symmetric matrix by CG-type method. The considered preconditioners are Point-SSOR, ILU (0) in the multi-coloring order, and Multi-Color Block SSOR (Symmetric Succesive OverRelaxation). We conducted our experiments on the CRAY­T3E with 128 nodes. The MPI (Message Passing Interface) library was adopted for the interprocessor communications. The test matrices are up to $512{\times}512$ in dimensions and were created from the discretizations of the elliptic PDE. All things considered the MC-BSSOR seems to be most robust preconditioner.

• YAKHAK HOEJI
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• v.41 no.6
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• pp.829-836
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• 1997

Studies on the effect of quinones on cardiac function has been conducted with normal hearts. But not with injured hearts, I.e. ischemia/reperfusion-injured heart. Quinone compounds are known to produce oxygen free radicals during metabolism, and for this reason, quinones are implicated in the aggravation of ischemia/reperfusion injury or cardioprotection, as in the case of ischemic preconditioning depending on the experimental conditions. The present study was carried out to examine the effect of 2-chloro-3-(4-cyanophenylamino)-1.4-naphthoquinone (NQ-Y15) on cardiac function of ischemic/reperfused and normal rat hearts. In isolated perfused hearts, various functional parameters such as left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (EDP) and maximum positive and negative dP/dt ($[\pm}dP/dt_{max}$), time to contracture, heart rate (HR) and coronary flow rate (CFR) were measured before and 30 min after dosing and following 25 min ischemia/30min reperfusion. NQ-Y15 increased LVDP, +dP/$d_{max}$and -dP/$dt_{min}$ by 18%. 30%, and 40%, respectively. There were no significant changes in other haemodynamic parameters. After ischemia/reperfusion injury, pretreatment with NQ-Y15 induced a significant decrease in LVDP and $[\pm}dP/dt_{max}$, but an increase in EDP. LDH-release was not significantly increased. These results suggested that NQ-Y15 may augment the ventricular contractility but it makes hearts more vulnerable to ischemia/reperfusion injury.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.6
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• pp.48-58
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• 2013

Characteristics of thermophysical properties and flow structures in a swirl injector at supercritical pressure have been investigated using the kerosene surrogate consisting of four species and various ideal and real gas equations of state. The quantitative comparisons of thermophysical properties for equations of state have been performed. Also, a large eddy simulation and preconditioning technique for getting an effective convergence rate are applied to analyze turbulent flow in a swirl injector. The flow characteristics in the injector has significantly different behaviors depending on the equations of state due to the different thermophysical properties in the injector. The Redlich-Kwong-Peng-Robinson equation of state provides the most suitable results in the wide range of temperature.

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.1-16
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• 1993

This paper describes an investigation to determine whether the activated sludge (AS) process could be used for the treatment of wastewater at the Union Carbide Coporation (UCC) plant in Seadrift, Texas. This plant presently utilizes a waste stabilization pond (WSP) system for treatment of the wastewater. The treatment system consists of an in-plant primary WSP and two off-plant WSPs (secondary and tertiary WSPs), run in series. The total hydraulic detention time of the WSP system is approximately 150 days. Several laboratory-based treatability studies have been conducted to evaluate the performace of the WSP system and the degradability of specific chemical compounds. From an additional study, it was determined that the WSP system was stressed and occasionally operating near the limit of its treatment capacity. The existing primary WSP plays an important role in the overall treatmemt system, because it not only functions as a pH and organic-strength equalization basin, but also serves as a "preconditioning" basin by fermenting high strength organic wastes to volatile organic acids for subsequent degradation in the escondary WSP. However, in view of pending RCRA legislatin conerning the "proposed organic toxicity characteristics limits" (40 CFR Part261: Federal Register, July, 1988), it is possible that the primary WSP will have to be abandoned in favor of alternative treatment options. Therefore the main purpose of this study was to perform activated sludge treatability evaluations for the development of an alternative to the existing primary WSP treatment ststem. In addition, another purpose was to determine the degradability of bis(2-chloroethyl)ether (Chlorex or CX) and benzene(BZ) in the activated sludge process. The presence of these two chemicals in the wastewater of the plant prompted the question of whatedether they could be degraded in an activated sludge system.

• Parasites, Hosts and Diseases
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• v.58 no.4
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• pp.461-466
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• 2020

Toxoplasma gondii is an obligate intracellular protozoan parasite that can invade various organs in the host body, including the central nervous system. Chronic intracranial T. gondii is known to be associated with neuroprotection against neurodegenerative diseases through interaction with host brain cells in various ways. The present study investigated the neuroprotective effects of chronic T. gondii infection in mice with cerebral ischemia experimentally produced by middle cerebral artery occlusion (MCAO) surgery. The neurobehavioral effects of cerebral ischemia were assessed by measurement of Garcia score and Rotarod behavior tests. The volume of brain ischemia was measured by triphenyltetrazolium chloride staining. The expression levels of related genes and proteins were determined. After cerebral ischemia, corrected infarction volume was significantly reduced in T. gondii infected mice, and their neurobehavioral function was significantly better than that of the uninfection control group. Chronic T. gondii infection induced the expression of hypoxia-inducible factor 1-alpha (HIF-1α) in the brain before MCAO. T. gondii infection also increased the expression of vascular endothelial growth factor after the cerebral ischemia. It is suggested that chronic intracerebral infection of T. gondii may be a potential preconditioning strategy to reduce neural deficits associated with cerebral ischemia and induce brain ischemic tolerance through the regulation of HIF-1α expression.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.2
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• pp.115-126
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• 2021

Strategic Environmental Impact Assessment (SEA) is a decision-making process taking into account the environmental impact, economic and social impact of policies, plans, and programs at the higher stage prior to the project plan for promoting sustainable development. In this study, we analyzed the process and criteria for selecting appropriate alternatives when establishing development plan in SEA. First, the criteria for estimating changes in ecosystem services following the implementation of development project of industrial complex were presented. Second, alternative evaluations were conducted through an analysis of ecosystem service scenarios to explore suitable alternatives in Anseong. As a result, the environmental quality of selected area as the existing project site deteriorated according to the implementation of the project, and the dimensional reduction technique confirmed that the change in ecosystem service factors in project area was the optimal location. In addition, the results of the scenario assessment to explore suitable alternatives in Anseong City showed that the existing site had large capacity in terms of water quality control services (scenario 1), scenario 2 in terms of preconditioning services, and scenario 3 in terms of water supply services. The guidance of Ecosystem service assessment is expected to be available in decision-making of large-scale strategies (e.g., SEA) and projects by presenting more quantitative criteria for determining the adequacy and location feasibility of development plans and policy plans. This is expected to require various support, including legislation and revision of related laws, believed to be supported by advanced research.

• Korean Journal of Veterinary Research
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• v.58 no.4
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• pp.211-217
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• 2018

Mesenchymal stem cells (MSCs) are useful candidates for tissue engineering and cell therapy. Physiological cell environment not only connects cells to each other, but also connects cells to the extracellular matrix that provide mechanical support, thus exposing the entire cell surface and activating signaling pathways. Hydrogel is a polymeric material that swells in water and maintains a distinct 3-dimensional (3D) network structure by cross linking. In this study, we investigated the optimized cellular function for canine adipose tissue-derived MSCs (cAD-MSCs) using hydrogel. We observed that the expression levels of Ki67 and proliferating cell nuclear antigen, which are involved in cell proliferation and stemness, were increased in transwell-hydrogel (3D-TN) compared to the transwell-normal (TN). Also, transforming growth factor-${\beta}1$ and SOX9, which are typical bone morphogenesis-inducing factors, were increased in 3D-TN compared to the TN. Collagen type II alpha 1, which is a chondrocyte-specific marker, was increased in 3D-TN compared to the TN. Osteocalcin, which is a osteocyte-specific marker, was increased in 3D-TN compared to the TN. Collectively, preconditioning cAD-MSCs via 3D culture systems can enhance inherent secretory properties that may improve the potency and efficacy of MSCs-based therapies for bone regeneration process.

• Asia-Pacific Journal of Business
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• v.12 no.1
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• pp.41-56
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• 2021

Purpose - This empirical study examined the influence of post-communist countries sociol-political factor of freedom of expression preconditioning, and trust in agency, mediating performance expectancy of social media users representing the citizens' behavioural intention to utilize social media in a post-communist country, the case of Mongolia. Design/methodology/approach - This research collected 403 valid survey data from citizens those who use social media in Mongolia. The study used Partial Least Squire (PLS) analysis with the research conceptual model founded on the UTAUT model. Findings - The study shown that citizens in post-communist, they strongly willing freedom of expression, which driving as a positive precondition factor, and this has an indirect positive influence, and trust in agency mediates to enhance performance expectancy. Social influence, and effort expectancy factors have direct positive influence on the intention to use of social media systems in the public sector domain of Mongolia. Research implications or Originality - This research proposed a new model to test citizens' intention to use social media as a communication tool to engage with public organizations in the pre-adoption stage of post-communist countries. Theoretically, this research builds up to the unique theoretical contribution with social media by examining a new social media-based third-party intercommunication medium, incorporating intent to utilize for citizens with government in post-communist countries. Practically, this article lays out the directions to aid social media usage for government sector with concerning citizens intentions in the post-communist situation.

• Asia-Pacific Journal of Business
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• v.11 no.2
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• pp.61-79
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• 2020

Purpose - This article empirically investigated the effects of the socio-political factor of censorship preconditioning, and organizational support, mediating performance expectancy of public sector officials' behavioural intention to utilise social media in a post-communist country, Mongolia. Design/methodology/approach - This study collected 212 survey data from public sector organisations in Mongolia. Using the Partial Least Squire (PLS) method, this study analyzed the proposal model grounded on the UTAUT model. Findings - There are still communist footprints in the form of censorship, which remained as a negative precondition factor, and this has an indirect negative influence, and organisational support mediates to enhance performance expectancy. Effort expectancy and social influence factors have direct positive influence on the use of social media systems in the government domain of Mongolia Research implications or Originality - This study empirically investigated the model of public employees' intention to examine the post-communist countries' cultural, social, economic, and political systems, government organisational environment of the former communist sphere. The cultural factors, censorship and organisational support, to the existing IT adoption UTAUT model were also identified to test the situation of a post-communist country, Mongolia. This study contributes to the new theoretical involvement with social media by testing a new social media-based third-party intercommunication channel, including intent to use in the public service for post-communist countries. This study practically provides the guidelines to promote social media usage for public sector in the post-communist situation.