• 아동학회지
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• 제26권6호
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• pp.393-409
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• 2005

This study examined effects of self-perceived obesity, peer victimization, stress, and maternal child rearing behaviors on self-esteem in an obese group(OG) and a normal weight group(NWG) of elementary school children. Subjects were 1,501 elementary school children in the 4th to the 6th grades in Seoul, Busan, Daegu, Gwangju, and Andong and their mothers. Major findings were that maternal child rearing behaviors and stress related to parents and home environments influenced children's self esteem only in the NWG; school-related stress was an influential variable on children's self esteem in both the NWG and OG. Peer victimization influenced children's self-esteem in both NWG and OG. Self-perceived obesity influenced some domains of children's self-esteem, especially in girls.

• Computers and Concrete
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• 제16권3호
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• pp.449-466
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• 2015

This paper aims to study the local bond stress-slip behavior of reinforcing bars embedded in lightweight aggregate concrete (LWAC). The experimental variables of the local bond stress-slip tests include concrete strength (20, 40 and 60 MPa), deformed steel bar size (#4, #6 and #8) and coarse aggregate (normal weight aggregate, reservoir sludge lightweight aggregate and waterworks sludge lightweight aggregate). The test results show that the ultimate bond strength increased with the increase of concrete compressive strength. Moreover, the larger the rib height to the diameter ratio ($h/d_b$) of the deformed steel bars is, the greater the ultimate bond stress is. In addition, the suggestion value of the CEB-FIP Model Code to the LWAC specimen's ultimate bond stress is more conservative than that of the normal weight concrete.

• Computers and Concrete
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• 제15권3호
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• pp.337-355
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• 2015

In this scientific work, an improved analytical solution for adhesive stresses in a concrete beam bonded with the FRP plate is developed by including the effect of the adherend shear deformations. The analysis is based on the deformation compatibility approach where both the shear and normal stresses are assumed to be invariant across the adhesive layer thickness. The shear stress distribution is supposed to be parabolic across the depth of the adherends in computing the adhesive shear stress and Timoshenko's beam theory is employed in predicting adhesive normal stress to consider the shear deformation. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of adhesive stress distributions.

• Steel and Composite Structures
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• 제38권4호
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• pp.355-363
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• 2021

The present paper attempts to investigate the propagation of plane waves in an isotropic elastic medium under the effect of initial stress and temperature-dependent properties. The modulus of elasticity is taken as a linear function of the reference temperature. The formulation is applied under the thermoelasticity theory with dual-phase-lag; the normal mode analysis is used to obtain the expressions for the displacement components, the temperature, the stress, and the strain components. Numerical results for the field quantities are given in the physical domain and illustrated graphically. Comparisons are made with the results predicted by different theories (Lord-Shulman theory, the classical coupled theory of thermoelasticity and the dual-phase-lag model) in the absence and presence of the initial stress as well as the case where the modulus of elasticity is independent of temperature.

• 한국임상약학회지
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• 제21권2호
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• pp.131-137
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• 2011

The purpose of this study was to evaluate the clinical efficacy of a standardized special ethanol extract from Gynostemma pentaphyllum as a management for anxiety and stress of normal population. This is a two-arm, parallelgroup, randomized, double blind clinical trial comparing Gynostemma pentaphyllum extract 200 mg bid (GP-EX, n=48) or placebo bid (n=54). The main outcome measures were the decrease in anxiety sensitivity index (ASI), the State version (S-STAI) of the Stait-Trait Anxiety Inventory (STAI) and the Trait version (T-STAT) of the STAI from baseline over a 6 weeks treatment period. In more anxious group (S-STAI50 or ASI19), the anxiety in group with GP-EX was decreased significantly than one in normal population with placebo [S-STAI50: T-STAI = from $57.7{\pm}6.5$ ($mean{\pm}S.D.$) to $46.8{\pm}11.2$ in normal population with GP-EX, p=0.002 vs. from $54.1{\pm}9.9$ to $49.0{\pm}9.6$ in normal population with placebo, p>0.05; ASI19: T-STAI = from $47.2{\pm}12.0$ to $42.4{\pm}11.1$ in normal population with GP-EX, p=0.022 vs. from $48.7{\pm}11.5$ to $46.0{\pm}10.4$ in normal population with placebo, p>0.05]. The most frequently reported adverse reactions considered possibly related to treatment were mild gastrointestinal events. GP-EX is more effective than placebo and is well tolerated as a therapy for anxiety and stress of normal population.

• Journal of applied mathematics & informatics
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• 제5권2호
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• pp.277-284
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• 1998

The reliability and an estimate for it are derived for series-parallel and parallel-deries stress-strength model under assumption that all components are subjected to a common stress. We also obtain the asymptotic normal distribution of the estimate.

• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.467-476
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• 2016

In the present study, we examined the effect of pertussis toxin (PTX) administered centrally in a variety of stress-induced blood glucose level. Mice were exposed to stress after the pretreatment of PTX (0.05 or 0.1 mg) i.c.v. or i.t. once for 6 days. Blood glucose level was measured at 0, 30, 60 and 120 min after stress stimulation. The blood glucose level was increased in all stress groups. The blood glucose level reached at maximum level after 30 min of stress stimulation and returned to a normal level after 2 h of stress stimulation in restraint stress, physical, and emotional stress groups. The blood glucose level induced by cold-water swimming stress was gradually increased up to 1 h and returned to the normal level. The intracerebroventricular (i.c.v.) or intrathecal (i.t.) pretreatment with PTX, a $G_i$ inhibitor, alone produced a hypoglycemia and almost abolished the elevation of the blood level induced by stress stimulation. The central pretreatment with PTX caused a reduction of plasma insulin level, whereas plasma corticosterone level was further up-regulated in all stress models. Our results suggest that the hyperglycemia produced by physical stress, emotional stress, restraint stress, and the cold-water swimming stress appear to be mediated by activation of centrally located PTX-sensitive G proteins. The reduction of blood glucose level by PTX appears to due to the reduction of plasma insulin level. The reduction of blood glucose level by PTX was accompanied by the reduction of plasma insulin level. Plasma corticosterone level up-regulation by PTX in stress models may be due to a blood glucose homeostatic mechanism.

• 대한한의학회지
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• 제25권2호
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• pp.194-206
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• 2004

Objectives : JiaoTeng-Yuan(교등원) is said to be a prescription for preservation of health in $\ulcorner$HuaTuo.ZhongZangJing (화타.중장경)$\lrcorner$. It is known to have the effect of Bu-Shen (보신: strengthening kidney) and Yi-Shou (익수: prolonging the span of one's life). This study investigates whether JTY is effective on inhibition of oxidation stress. Methods : Sprague-Dawley rats (12-week-old, weight $300{\pm}20g$) were divided into 3 groups. The normal group (n=8) was injected with PBS (1ml/body, s.c) subcutaneously behind the neck. The control group (n=8) was injected with D-galactose (50mg/kg, 1ml PBS/body, s.c) to induce pathological animals. The JTY group was injected with the same treatment as the control group, and fed containing JTY (10%). All groups were treated 1 time per day for 6 weeks. After the rats were sacrificed anti-oxidant enzyme (SOD, CAT, G-px) activity, GSH quantity of RBC and tissue (heart, liver and kidney), and plasma Vit-C quantity were examined. Also, the MDA levels of liver and kidney, lipofuscin of heart and endurance of erythrocyte membrane were measured. Results : In the JTY group, RBC's SOD activity decline was halted by 21 % of the normal level, compared to the control group, G-px activity (unit/g of Hb) increased significantly, compared to the normal group, and the level of Vit-C in plasma increased by 16%. Heart's SOD activity was kept at the same level as that of the normal group; and CAT activity decline was halted by 26%. Kidney's CAT and G-px activities were kept at the same level as that shown in the normal group, implying the existence of a halting effect. Liver also showed a slight halting effect against the decline of anti-oxidant ability, but the effect was not significant (${\alpha}=0.05$). A comparison between the levels of peroxide in SD rats showed that the level of TBARS in plasma increased significantly in the control group and that it was normal in the JTY group. The livers in the JTY group, compared to those in the control group, showed 36% halting effect of the normal level while their kidney's indicated the level significantly lower than the normal level. Heart's lipofuscin increased significantly in the control group, but was alike in both the JTY and the normal groups. Endurance of erythrocyte membrane (%) decreased significantly in the control group while it was kept at the similar level in both the JTY and the normal groups, indicating the halting effect. Conclusions : This study suggests that JTY is effective to defend oxidation stress caused by D-galactose in the animals. It showed that the anti-oxidant ability was maintained and strengthened. On the other hand, it reduced the level of peroxide in animals. In sum, JTY appeared to have the equilibrium normal physiological function in SD rat.

• 동력기계공학회지
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• 제16권2호
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• pp.43-48
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• 2012

Generally accelerated life test is well known as one method to reduce reliability qualification test period. This test is conducted under the higher stress condition than normal condition. So it can save the test time by calculating the acceleration factor from the relationship between the worst stress condition and normal condition. This paper investigates the worst stress condition for the accelerated life test to increase the acceleration factor. Especially, we focused on the method to obtain effective acceleration factors under the worst stress condition. Moreover, we considered how to decide the worst stress condition by looking for the operating limit of this system. The acceleration factor can be estimated from the ratio of the kinematic viscosity in the normal condition and the worst stress condition, the lowest temperature, by using Arrhenius relationship. Through some experiments for a refrigerator's compressor, we were able to confirm how to increase acceleration factors and how to reduce the reliability qualification test period with minimum samples.

• The Journal of Korean Physical Therapy
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• 제24권1호
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• pp.15-21
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• 2012

Purpose: The purpose of this study was to investigate the influence of adolescent's scoliosis on the stress level and study-attitude, to inform the public that there exist an important correlation between adolescent's scoliosis and stress, as well as, study-attitude, using a questionnaire. Methods: For this study, questionnaires were distributed to elementary school in G city from May 10 through May 31, 2011. This study measured a primary scoliosis-test by a scoliometer with 300 elementary school students and a secondary test by Cobb's angle using an X-ray. The subjects were divided into 2 groups (normal group (n=20), scoliosis group (n=20)). The collected data were analyzed by a t-test and Pearson analysis. Results: As a result of this study, the Cobb's angle showed significant difference between the scoliosis group and the normal group (p<0.001). Also, it tended to have a greater stress level in the scoliosis group than the relationship between scoliosis and the stress or study-attitude compared to the normal group (p<0.05). The correlation of stress according to Cobb's angle showed a positive relationship (r=0.36), and the correlation of study-attitude to Cobb's angle showed a negative relationship (r=-0.04). Conclusion: In conclusion, this study showed that scoliosis affects stress and study-attitude. We hope that this result would help diagnose adolescent's scoliosis in anearly stage and prevent any phychologic and social problems relating to it.