Differences in the relationship between traumatic experiences, self-esteem, negative cognition, and Internet addiction symptoms among North Korean adolescent defectors and South Korean adolescents: A preliminary study

Park, Subin,Lee, Yeeun,Jun, Jin Yong Elsevier/North Holland Biomedical Press 2017 Psychiatry research Vol.257 No.-

<P><B>Abstract</B></P> <P>North Korean adolescent defectors experience adaptation difficulties along with a wide range of psychosocial problems, but no study has yet examined their Internet addiction symptoms. We compared early traumatic experiences, self-esteem, negative cognition, and Internet addiction symptoms, as well as the relationships between these variables, between North Korean adolescent defectors and South Korean adolescents. Fifty-six North Korean adolescent defectors and 112 age- and sex- matched South Korean adolescents participated. The analyses examined the relationship between traumatic experiences and Internet addiction symptoms, with negative automatic thoughts or low self-esteem as mediators of these relations. North Korean adolescent defectors tended to have higher levels of negative automatic thoughts and more severe Internet addiction symptoms, as well as better self-esteem, than did South Korean adolescents. Furthermore, only among North Korean adolescent defectors, traumatic experiences were positively associated with Internet addition symptoms via increasing negative automatic thoughts. North Korean adolescent defectors are more susceptible to Internet addiction, negative cognitions, and early traumatic experiences compared to South Korean adolescents. However, the cross-sectional design of this study precludes consideration of the causality of these relationships. Interventions aiming to correct negative cognitions and increase self-esteem may be helpful for North Korean adolescent defectors with problematic Internet use.</P> <P><B>Highlights</B></P> <P> <UL> <LI> North Korean adolescent defectors had higher trauma and Internet addiction (IA). </LI> <LI> North Korean defectors also had greater self-esteem and negative automatic thoughts. </LI> <LI> Self-esteem and negative thoughts were mediators in the relation of trauma and IA. </LI> <LI> Country of origin (North vs. South Korea) moderated the mediating effects. </LI> </UL> </P>

A compound (DW1182v) protecting high glucose/palmitate-induced glucolipotoxicity to INS-1 beta cells preserves islet integrity and improves hyperglycemia in obese db/db mouse

Lee, S.J.,Choi, S.E.,Hwang, Y.C.,Jung, I.R.,Yi, S.A.,Jung, J.G.,Ku, J.M.,Jeoung, K.,Han, S.J.,Kim, H.J.,Kim, D.J.,Lee, K.W.,Kang, Y. North-Holland ; Elsevier Science Ltd 2012 european journal of pharmacology Vol.696 No.1

Loss of beta cells is a pathogenic cause for the development of type 2 diabetes. High glucose/free fatty acid (HG/FFA)-induced glucolipotoxicity was thought to play a role in the beta cell loss. Thus, application of small molecules capable of preventing HG/FFA-induced glucolipotoxicty to beta cells could be an avenue for a therapeutic intervention for the development of type 2 diabetes. We screened a representative library supplied from Korean Chemical Bank for prevention of high glucose/palmitate (HG/PA)-induced viability reduction of INS-1 beta cells and were able to identify a new small molecule (DW1182v) with a function to protect HG/PA-induced glucolipotoxicity. The protective effect was specific to HG/PA-induced beta cell death since DW1182v did not protect streptozotocin- or cytokine-induced INS-1 cell death. The protective effect by DW1182v was likely due to the reduction of death-promoting endoplasmic reticulum (ER) stress responses such as phospho-C-Jun N-terminal kinase (JNK) and C/EBP homologous protein (CHOP). Treatment of obese diabetic db/db mice with DW1182v preserved islet integrity and thus increased insulin secretion and lowered blood glucose after glucose infusion. These results suggest that a small molecule protecting HG/PA-induced glucolipotoxicity to beta cells can be a new therapeutic candidate to prevent the development of type 2 diabetes.

Chlorogenic acid ameliorates brain damage and edema by inhibiting matrix metalloproteinase-2 and 9 in a rat model of focal cerebral ischemia

Lee, K.,Lee, J.S.,Jang, H.J.,Kim, S.M.,Chang, M.S.,Park, S.H.,Kim, K.S.,Bae, J.,Park, J.W.,Lee, B.,Choi, H.Y.,Jeong, C.H.,Bu, Y. North-Holland ; Elsevier Science Ltd 2012 european journal of pharmacology Vol.689 No.1

Chlorogenic acid (CGA) has been reported to have various beneficial effects on the cardiovascular and central nervous systems. The purpose of the current study was to investigate whether CGA has protective effects against cerebral ischemia and whether these effects are due to modification of brain edema-related vascular factors. In a rat model of transient middle cerebral artery occlusion (MCAo, 2h of occlusion followed by 22h of reperfusion), we measured infarct volume and performed behavioral test to evaluate the effects of CGA on brain damage and sensory-motor functional deficits. Brain water content and Evans blue extravasation were measured to evaluate brain edema and blood brain barrier (BBB) damage. Lipid peroxidation (LPO) and the expressions and activities of matrix metalloproteinase (MMP)-2 and MMP-9 were measured to investigate the mechanisms of action. Intraperitoneal injection of CGA (3, 10, and 30mg/kg) at 0h and 2h after MCAo dose-dependently reduced infarct volume and sensory-motor functional deficits. It also reduced brain water content and Evans blue extravasation. Mechanistically, CGA reduced LPO and MMPs expressions and activities. These results suggest that CGA reduces brain damage, BBB damage and brain edema by radical scavenging activity and the inhibitory effects on MMP-2 and MMP-9.

Wound-healing effect of ginsenoside Rd from leaves of Panax ginseng via cyclic AMP-dependent protein kinase pathway

Kim, W.K.,Song, S.Y.,Oh, W.K.,Kaewsuwan, S.,Tran, T.L.,Kim, W.S.,Sung, J.H. North-Holland ; Elsevier Science Ltd 2013 european journal of pharmacology Vol.702 No.1

Panax ginseng is considered as one of the most valuable medicinal herbs in traditional medicine, and ginsenoside Rd is one of the main active ingredients in P. ginseng leaf. Although there is significant number of evidences implicated on the beneficial effects of the ginsenosides with diverse associated mechanisms, reports on the skin regeneration by the ginsenoside Rd are not sufficient. Therefore, we examined the mitogenic and protective effects of the ginsenoside Rd in the keratinocyte progenitor cells (KPCs) and human dermal fibroblasts (HDFs). Furthermore, the signaling pathways involved in the activation of KPCs and HDFs were investigated, and wound-healing effect is evaluated in vivo through animal wound models. We found that the ginsenoside Rd significantly increased the proliferation and migration level of KPCs and HDFs in a dose-dependent manner. Additionally, the cell survival was significantly increased in H<SUB>2</SUB>O<SUB>2</SUB> treated KPCs. Moreover, the ginsenoside Rd effectively induced collagen type 1 and down-regulated matrix metalloprotinase-1 (MMP-1) in a dose-dependent manner. All of these beneficial effects are associated with an induction of intracellular cAMP levels and phosphorylated cAMP response element-binding protein expression in nucleus, which both attenuated by adenine 9-β-d-arabinofuranoside, an adenylate cyclase inhibitor. Application of the ginsenoside Rd to an excision wound in mice showed an effective healing process. As skin regeneration is mainly associated with the activation of HDFs and KPCs, P. ginseng leaf, an alternative source of the ginsenoside Rd, can be used as a natural source for skin regeneration.

In-operation modal analysis of containments using ambient vibration

Choi, S.,Park, S.,Hyun, C.H.,Kim, M.S. North-Holland Pub. Co 2013 Nuclear engineering and design Vol.260 No.-

The importance of preserving the structural integrity of a containment can never be overemphasized. Currently the structural integrity of the containment is evaluated periodically via various nondestructive inspection methods. However, these methods can only provide local integrity data, and cannot deliver continuous monitoring information on overall structural integrity. In this paper, the result of a feasibility study on utilizing ambient vibration measurements to monitor the structural integrity of a containment is presented. The ambient vibration testing was selected, because it can avoid the interruption of normal operation of power plants. For the purpose of the study, the ambient vibration of four different containments in Korea, i.e. Ulchin Unit 5, Wolsong Unit 2, Ulchin Unit 1, and Yeonggwang Unit 4, was measured and modal parameters were extracted via frequency domain modal analysis techniques. The experimental modes were then compared to the analytical modes estimated using finite element analysis to examine the correlation, and highly correlated modes were adopted in identifying structural parameters using a system identification method. The structural parameter selected in this study was the elastic modulus of the concrete, and the identified moduli were compared to design values and inspection results. The result shows the ambient vibration can be utilized in monitoring the structural integrity of a containment, though further extensive study needs to be conducted to identify and exclude the effect of ambient conditions such as temperature and humidity on resonant frequencies.

The procyanidin trimer C1 induces macrophage activation via NF-κB and MAPK pathways, leading to Th1 polarization in murine splenocytes

Sung, N.Y.,Yang, M.S.,Song, D.S.,Byun, E.B.,Kim, J.K.,Park, J.H.,Song, B.S.,Lee, J.W.,Park, S.H.,Park, H.J.,Byun, M.W.,Byun, E.H.,Kim, J.H. North-Holland ; Elsevier Science Ltd 2013 european journal of pharmacology Vol.714 No.1

Numerous studies have shown various relationships between foods with a high nutritional value and a robust immune response, particularly studies that have focused on host protection and cytokine networks. This study aimed to clarify the role played by the procyanidin trimer C1 in innate and adaptive immunity. Procyanidin C1 did not exert cytotoxicity at concentrations ranging from 7.8 to 62.5μg/ml in macrophage cells; therefore, concentration of 62.5μg/ml was used as the maximum dose of procyanidin C1 throughout subsequent experiments. Procyanidin C1 enhanced inducible nitric oxide synthase-mediated nitric oxide production in a concentration-dependent manner. In addition, procyanidin C1 functionally induced macrophage activation by augmenting the expression of cell surface molecules (CD80, CD86, and MHC II) and proinflammatory cytokine production (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6) via activation of mitogen-activated protein kinase (MAPK), e.g., p38, ERK, and JNK and nuclear factor (NF)-κB signaling pathways. Interestingly, procyanidin C1 effectively polarized T helper type 1 (Th1) by secreting Th1-mediated cytokines (interferon-γ, IL-12p70, and IL-2) and inducing splenocyte proliferation, indicating that procyanidin C1 contributes to Th1 polarization of the immune response. Accordingly, these findings confirms that the procyanidin C1 induces macrophage activation via NF-κB and MAPK pathways, leading to Th1 polarization in murine splenocytes, which suggests that procyanidin C1 regulates innate and adaptive immunity by macrophage activation and Th1 polarization.

Neuroprotective effect of 3-morpholinosydnonimine against Zn²⁺-induced PC12 cell death

An, J.M.,Moon, S.A.,Hong, S.Y.,Kang, J.W.,Seo, J.T. North-Holland ; Elsevier Science Ltd 2015 european journal of pharmacology Vol.748 No.-

Excessive intracellular accumulation of zinc (Zn<SUP>2+</SUP>) is neurotoxic and contributes to a number of neuropathological conditions. Here, we investigated the protective effect of 3-morpholinosydnonimine (SIN-1) against Zn<SUP>2+</SUP>-induced neuronal cell death in differentiated PC12 cells. We found that Zn<SUP>2+</SUP>-induced PC12 cell death was reduced in a concentration-dependent manner by pretreatment with SIN-1. The intracellular accumulation of Zn<SUP>2+</SUP> was not affected by pretreatment with SIN-1, indicating that SIN-1-induced neuroprotection was not attributable to reduced influx of Zn<SUP>2+</SUP> into cells. SIN-1C, the stable decomposition product of SIN-1, failed to prevent Zn<SUP>2+</SUP>-induced cell death. Furthermore, the protective effect of SIN-1 against Zn<SUP>2+</SUP>-induced PC12 cell death was almost completely abolished by uric acid, a free radical scavenger, suggesting that reactive oxygen and nitrogen species generated by SIN-1 may contribute to the protective effect. SIN-1 prevented the inactivation of glutathione reductase (GR) and the increase in the ratio of oxidized glutathione/total glutathione (GSSG/total GSH) induced by Zn<SUP>2+</SUP>. Addition of membrane permeable GSH ethyl ester (GSH-EE) to PC12 cells prior to Zn<SUP>2+</SUP> treatment significantly increased cell viability. We therefore conclude that SIN-1 may exert neuroprotective effect against Zn<SUP>2+</SUP>-induced cell death in differentiated PC12 cells by preventing inhibition of GR and increase in GSSG/total GSH ratio.

Finite element limit loads for non-idealized through-wall cracks in thick-walled pipe

Shim, D.J.,Han, T.S.,Huh, N.S. North-Holland Pub. Co 2013 Nuclear engineering and design Vol.265 No.-

The present paper provides plastic limit loads for non-idealized through-wall cracks in thick-walled pipe. These solutions are based on detailed 3-dimensional finite element (FE) analyses which can be used for structural integrity assessment of nuclear piping. To cover a practical range of interest, the geometric variables and loading conditions affecting the plastic limit loads of thick-walled pipe with non-idealized through-wall cracks were systematically varied. In terms of crack orientation, both circumferential and axial through-wall cracks were considered. As for loading conditions, axial tension, global bending, and internal pressure were considered for circumferential cracks, whereas only internal pressure was considered for axial cracks. Furthermore, the values of geometric factor representing shape characteristics of non-idealized through-wall cracks were also systematically varied. In order to provide confidence in the present FE analyses results, plastic limit loads of un-cracked, thick-walled pipe resulting from the present FE analyses were compared with the theoretical solutions. Finally, correction factors to the idealized through-wall crack solutions were developed to determine the plastic limit loads of non-idealized through-wall cracks in thick-walled pipe.

Thermal-fluidic characteristics of a high temperature heater in an experimental helium loop for VHTR simulations

Yoon, C.,Hong, S.D.,Noh, J.M.,Kim, Y.W.,Chang, J. North-Holland Pub. Co 2013 Nuclear engineering and design Vol.264 No.-

A medium-scale helium loop for simulating a VHTR (Very High Temperature Reactor) is now under construction in KAERI (Korea Atomic Energy Research Institute). Two electric heaters of the test helium loop heat the helium fluid up to 950<SUP>o</SUP>C at a pressure of 1-9MPa. To optimize the design specifications of the experimental helium loop, conjugate heat transfer in the high-temperature helium heater was analyzed using CFD (Computational Fluid Dynamics) simulations. The main factors tested in this CFD analysis were the effects of turbulence, radiation, gravity, and geometrical configuration of the heater. From the analysis results, the optimum design configuration was selected confirming that the thermal characteristics of the heater meet the design requirements well. In this study, the interrelated effects of buoyancy forces and radiation heat transfer on the geometrical configuration were closely investigated. It was concluded that the buoyancy effects on the helium flows of the heater would be suppressed by the radiation heat transfer inside the heating channel. Various emissivity values of the reflector materials were also tested. Gravity had greater effect on the temperature distribution for a lower emissivity, but the maximum temperature variations due to the emissivity changes from 0.1 to 0.9 were limited to within a few tens of degrees. Finally, more detailed analyses on the HTH (high temperature heater) of the medium scale helium loop including the spacers were performed, and it was confirmed that the thermal-fluidic characteristics of the HTH satisfied the design requirements.

Evolutionary developments of advanced PWR nuclear fuels and cladding materials

North-Holland Pub. Co 2013 Nuclear engineering and design Vol.263 No.-

The evolutionary developments of advanced PWR fuels and cladding materials are explained with outstanding design features of nuclear fuel assembly components and zirconium-base cladding materials. The advanced PWR fuel and cladding materials development processes are also provided along with verification tests, which can be used as guidelines for newcomers planning to develop an advanced fuel for the first time. The up-to-date advanced fuels with the advanced cladding materials may provide a high level of economic utilization and reliable performance even under current and upcoming aggressive operating conditions. To be specific, nuclear fuel vendors may achieve high fuel burnup capability of between 45,000 and 65,000MWD/MTU batch average, overpower thermal margin of as much as 15% and longer cycle length up to 24 months on the one hand and fuel failure rates of around 10<SUP>-6</SUP> on the other hand. However, there is still a need for better understanding of grid-to-rod fretting wear mechanisms leading to major PWR fuel defects in the world and subsequently a driving force for developing innovative spacer grid designs with zero fretting wear-induced fuel failure.