• Title/Summary/Keyword: stress resistance

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Antioxidant Action of Ginseng : An hypothesis (인삼의 항산화 작용)

  • Lee, D.W.;Sohn, H.O.;Lim, H.B.;Lee, Y.G.;Aprikian, A.G.;Aprikian, G.V.
    • Journal of Ginseng Research
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    • v.19 no.1
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    • pp.31-38
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    • 1995
  • Antioxidant effect of Korean ginseng (Panax ginseng C.A. Meyer) was investigated in rats. Long-term administration of ginseng water extract protected the activity of liver cytosotic SOD, catalase and glutathione peroxidase from being significantly decreased with advancing age (p<0.05). It was more effective toward glutathione peroxidase than other antioxidant enzymes. However, the level of sulfhydryl compounds and its related enzymes such as glutathione reductase and glutathione-5-transferase was not significantly changed by the administration of ginseng. Liver microsomal formation of reactive oxygen species such as superoxide and hydrogen peroxide did not show a significant difference between two groups although it was slightly decreased with age, but lipid peroxidizability of microsomal membrane induced by a prooxidant was slightly lower in ginseng-treated rats. Interestingly, antioxidant capacity of plasma from ginseng treated rats on autooxidation of ok-brain homogenates was much higher than that of normal ones. However, resistance of RBC membrane against oxidative stress showed a similar tendency. The content of serum TBA reactive substances lowered consistently in the rats treated with r ginseng at all corresponding age and a significant difference between two groups was found at 24 months of age (p<0.05). Ginseng extract protected lipid peroxidation in brain and liver. This protection was more effective in the stressed rats imposed by immobilization than normal ones. In conclusion, ginseng water extract protected the age related deterioration of major antioxidant enzymes, and this effect was more striking with increasing duration of treatment. This comprehensive antioxidant action of ginseng seems to be bra certain action of ginseng other than a direct antioxidant action, which might be a long term normalizing effect through the harmony of various components.

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Genome-Based Insights into the Thermotolerant Adaptations of Neobacillus endophyticus BRMEA1T

  • Lingmin Jiang;Ho Le Han;Yuxin Peng;Doeun Jeon;Donghyun Cho;Cha Young Kim;Jiyoung Lee
    • Research in Plant Disease
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    • v.29 no.3
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    • pp.321-329
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    • 2023
  • The bacterium Neobacillus endophyticus BRMEA1T, isolated from the medicinal plant Selaginella involvens, known as its thermotolerant can grow at 50℃. To explore the genetic basis for its heat tolerance response and its potential for producing valuable natural compounds, the genomes of two thermotolerant and four mesophilic strains in the genus Neobacillus were analyzed using a bioinformatic software platform. The whole genome was annotated using RAST SEED and OrthVenn2, with a focus on identifying potential heattolerance-related genes. N. endophyticus BRMEA1T was found to possess more stress response genes compared to other mesophilic members of the genus, and it was the only strain that had genes for the synthesis of osmoregulated periplasmic glucans. This study sheds light on the potential value of N. endophyticus BRMEA1T, as it reveals the mechanism of heat resistance and the application of secondary metabolites produced by this bacterium through whole-genome sequencing and comparative analysis.

Shear Load-Transfer Function of Rock-Socketed Drilled Shafts Considering Borehole Roughness (굴착면 거칠기를 고려한 암반 근입 현장타설말뚝의 주면 하중전이함수 제안)

  • Seol, Hoon-Il;Woo, Sang-Yoon;Han, Keun-Taek;Jeong, Sang-Seom
    • Journal of the Korean Geotechnical Society
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    • v.22 no.7
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    • pp.23-35
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    • 2006
  • Shear load transfer characteristics of rock-socketed drilled shafts were analyzed. The constant normal stiffness (CNS) direct shear tests were performed to identify the major influencing factors of shaft resistance, i.e., unconfined compressive strength, borehole roughness, normal stiffness, initial confining stress, and material properties. Based on the CNS tests, shear load transfer function of drilled shafts in rocks is proposed using borehole roughness and the geological strength index (GSI), which indicates discontinuity and surface condition of rock mass in Hoek-Brown criterion (1997). The proposed load-transfer function was verified by the load test results of seven rock-socketed drilled test shafts subjected to axial loads. Through comparisons of the results of load tests, it is found that the load-transfer function by the present study is in good agreement with the general trend observed by in situ measurements, and thus represents a significant improvement in the prediction of load transfer of drilled shafts.

A Study on Vibratory Behavior of Steel Sheet Pile Installed in Sand Ground (모래지반에 대한 강널말뚝의 진통항타거동 연구)

  • Lee, Seung-Hyun;Lee, Jong-Ku;Yoo, Wan-Kyu;Kim, Byoung-Il
    • Journal of the Korean Geotechnical Society
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    • v.23 no.4
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    • pp.79-90
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    • 2007
  • Behaviors of instrumented steel sheet piles which are installed in sand ground by vibratory hammer were investigated. Especially, stresses acting on the pile during vibratory driving, efficiency factor which reflects differences between theoretical driving force and actually delivered acting force, justifiability of rigidity of steel sheet pile, dynamic resistance characteristics of soil and penetration characteristics of sheet pile were analysed. According to the field test results it is justifiable that steel sheet pile behaves as a rigid body during vibratory driving. And it can be seen that maximum stress acting on sheet pile section is far less than tensile strength of the material. Value of the maximum section force at sheet pile head was 72% of that estimated from theoretical equation. Magnitudes of displacement amplitudes computed from displacement-time history curve corresponding to four penetration depths were in the range of 16 $\sim$ 75% of that specified by manufacturer.

Estimation of Undrained Shear Strength for Clays Using Effective Cone Factor (유효콘계수를 이용한 포화점토의 비배수전단강도 평가)

  • Kim, Chang-Dong;Kim, Soo-Il;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.24 no.11
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    • pp.133-141
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    • 2008
  • In this study, a new method for estimating the undrained shear strength $s_u$ of saturated clays using piezocone penetration test (CPTu) result is proposed. This is to develop more effective CPTu-based $s_u$ estimation method at lower cost with less uncertainty. For this purpose, a marine clay deposit is selected and tested through extensive experimental testing program including both in-situ and fundamental laboratory tests. The proposed method is based on a correlation between the undrained shear strength $s_u$ and the cone resistance $q_t$, without introduction of the total overburden stress into the $s_u-q_t$ correlation. As a result, no additional testing procedure for collecting undisturbed soils samples is required, which can reduce overall testing cost. To verify the proposed method, 4 test sites, which consist of a variety of soil conditions, are selected and used for comparison between measured and predicted undrained shear strength. From comparison, it is seen that predicted values of $s_u$ using the proposed method match well those from measured results.

Turbidity Calibration of Borehole Roughness Measurement System (BKS-LRPS) Usable in Water (수중에서 사용가능한 굴착공 벽면거칠기 측정 시스템(BKS-LRPS)의 굴착공 내 혼탁도 보정에 관한 연구)

  • Park, Bong-Geun;Choi, Yong-Kyu;Kim, Myung-Hak;Kwon, Oh-Kyun;Nam, Moon-S.
    • Journal of the Korean Geotechnical Society
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    • v.24 no.10
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    • pp.25-32
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    • 2008
  • Based on recent studies, the side resistance of rock socketed drilled shafts was affected by unconfined compressive strength of rock, socket roughness, rock types and joints, and initial normal stress. Especially, the socket roughness was affected by rock types and joints, drilling methods, and diameters of pile. In this study, a new roughness measurement system (BKS-LRPS, Backyoung-KyungSung Laser Roughness Profiling System) usable in water was developed. Based on the laboratory model tests, an EMD (Effective Measurement Distances) according to various turbidity was proposed as $EMD=1149.2{\times}T_{b}^{-0.64}$.

Calibration of Borehole Roughness Measurement System for Large Diameter Drilled Shafts in Water (수중에서 적용가능한 대구경 현장타설말뚝의 굴착공 벽면거칠기 측정장치의 보정에 관한 연구)

  • Park, Bong-Geun;Nam, Moon-S.;Choi, Yong-Kyu
    • Journal of the Korean Geotechnical Society
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    • v.25 no.8
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    • pp.5-21
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    • 2009
  • Based on recent studies on rock socketed drilled shafts, it was found that the side resistance of rock socketed drilled shafts is affected by unconfined compressive strength of rock, socket roughness, rock types and joints, and initial normal stress. Especially, the socket roughness is affected by rock types and joints, drilling methods, and diameters. Since existing roughness measurement systems could be conducted only in the air, a new roughness measurement system, which can measure rock socket roughness in the air and also in the water, is needed. However, the development of new roughness measurement system fur civil engineers has been faced with difficulties of electrical applications. In this study, the laboratory verification system far BKS-LRPS (Backyoung-KyungSung Laser Roughness Profiling System) was developed, which can be applied both in the water and air. Based on the laboratory verification, it was found that the improved BKS-LRPS could define effective measurement distances for the conditions reflecting the apparatus and in-situ situations.

Effects of High-Frequency Treatment using Radiofrequency on Autonomic Nervous System and Pain in Women with Dysmenorrhea

  • Sungeon Park;Seungwon Lee;Inok Kim
    • Physical Therapy Rehabilitation Science
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    • v.11 no.4
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    • pp.493-501
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    • 2022
  • Objective: The purpose of this study is to present basic data for appropriate therapeutic intervention by confirming changes in the autonomic nervous system and pain by applying high-frequency deep diathermy to the lower abdomen in patients with primary dysmenorrhea. Design: A randomized controlled clinical trial. Methods: Thirty-eight women aged 18-50 years who complained of regular menstrual cycles (24-32 days) and primary dysmenorrhea symptoms were randomly assigned to a high-frequency therapy group (5, 7, or 9 mins) and a superficial heat therapy group (20 min). High frequency treatment group: The subject was in a supine position, and radio frequency was applied to the lower abdomen below the umbilicus. The radio frequency therapy device used in this study uses a 300 kHz capacitive electrode and a 500 kHz resistive electric transfer to deliver deep heat. Superficial heat treatment Group: Subjects applied a hot pack to the lower abdomen for 20 minutes while lying on their back. Evaluations were made of Heart rate variability and Visual Analogue Scale. Results: In subjects with menstrual pain, there was a significant difference in pain between the high-frequency therapy group and the superficial heat therapy group (p=0.026). However, there was no significant difference between the autonomic nervous system and the stress resistance (p>0.05). Conclusions: As a result of this study, high-frequencytreatment using radiofrequency was effective in relieving pain because it can penetrate deeper tissues than conventional hot packs using superficial heat. In particular, it was found that the optimum effect was obtained when high frequency was applied forfive-seven minutes.

Study of the Soilnail-Slope Design Method Considering Bending Resistance of Soilnail (휨저항을 고려한 쏘일네일보강사면의 해석에 관한 연구)

  • Joo, Yong-Sun;Kim, Nak-Kyung;Kim, Sung-Kyu;Park, Jong-Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.6C
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    • pp.331-338
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    • 2008
  • Soil nailing is used as a method of slope stabilization and excavation support. The design method of soil nail are based on experience or assumption of interaction between soil and reinforcement. Most design methods simply considers the tension of reinforcement for analysis of slope stabilization. Soil nails interact with soils under combined loading of shear and tension. Jewell & Pedley suggested a design equation of shear force with bending stiffness and discussed that the magnitude of the maximum shear force is small in comparison with the maximum axal force. However, they have used a very conservative limiting bearing stress on nails. This paper discusses that the shear strength of soil nails should not be disregarded with proper bearing stresses on nails. The modified FHWA design method was proposed by considering shear forces on nails with bending stiffness.

Current Status of International Standardization for Durability Test Methods in Smart Clothing and Future Challenges in Enhancing Product Reliability and Quality Control (스마트 의류의 사용환경 내구성 시험에 대한 국제 표준화 현황과 제품의 신뢰성 향상 및 품질 관리를 위한 향후 과제)

  • Siyeon Kim;Ga-Young Lim;Sukyung Kim;Junghyun Lee
    • Fashion & Textile Research Journal
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    • v.25 no.3
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    • pp.398-408
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    • 2023
  • Smart clothing products can experience a decrease in performance and reliability due to various mechanical, biological, and chemical stress factors that occur throughout their life cycle. These issues can hinder consumer acceptance of the products. This study aims to enhance the reliability of smart clothing and facilitate quality control by analyzing and identifying the current status of international standardization for smart clothing and electronic textiles (e-textiles). The focus of this analysis was on the durability test methods in the use environment. Furthermore, similar standards published by different standardization organizations for durability tests were compared in depth. The study showed that a total of 27 international standards have been developed or are currently under development. The current standardization efforts mainly aim to develop functionality and durability test methods for smart clothing and e-textile products. A detailed comparison was made between two international standards (IEC 63023-204-1:2023 and AATCC TM210:2019) specifically in relation to the washing durability test method and the electrical resistance measurement standards (BS EN 16812:2016 vs AATCC EP13-2021), before and after the environmental exposure tests. Based on this comparison, several suggestions have been made and discussed for the future revision of these international standards.