• Title/Summary/Keyword: stress recovery

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The clinical study on 2 cases of patients with head and face symptoms of stress (Stress로 인한 두면부(頭面部) 증상(症狀) 치료(治療) 2례(例)에 대한 증례보고(證例報告))

  • Park, Jung-Hyeun;Lee, Hyun
    • Journal of Haehwa Medicine
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    • v.15 no.1
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    • pp.71-78
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    • 2006
  • Objective : The purpose of this study is to report to treat two patients who had symptoms on head and face because of stress. Methods : The changes in symptoms of heat on right bucca, spasm of upp. er lip, left parietal pain, in individual expression were described as they were treated with acupuncture therapy named An-sim-bang(安心方), moxibustion and herb medicine. Results : Symptoms of heat on right bucca, spasm of upp. er lip, left parietal pain at admission improved and disapp eared gradually with acupuncture therapy named An-sim-bang(安心方), moxibustion and herb medicine. The patients could discharge with favorable recovery. Conclusion : In oriental medicine, stress is mainly treated by taking down flaring-up of heart fire, removing depression of Ki and fulling up deficiency of Yin of the kidneys. We experienced that these treatments by acupuncture therapy named An-sim-bang(安心方), moxibustion and herb medicine have the effect treating symptoms on head and face because of stress.

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High Temperature Deformation Behavior of SiCp/2124Al Metal Matrix Composites

  • Tian, Y.Z.;Cha, Seung I.;Hong, Soon H.
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2002.05a
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    • pp.69-72
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    • 2002
  • The high temperature deformation behavior of SiCp/2124Al composite and 2124Al alloy was investigated by hot compression test in a temperature ranged $400~475^{\circ}C$ over a strain rate ranged $10^{-3}~1s^{-1}$. The billets of 2124Al alloy and SiCp/2124Al composite were fabricated by vacuum hot pressing process. The stress-strain curve during high temperature deformation exhibited a peak stress, and then the flow stress decreased gradually into a steady state stress with increasing the strain. It was found that the flow-softening behavior was attributed to the dynamic recovery, local dynamic recrystallization and dynamic precipitation during the deformation. The precipitation phases were identified as S' and S by TEM diffraction pattern. Base on the TEM inspection, the relationship between the Z-H parameter and subgrain size was found based on the experiment data. The dependence of flow stress on temperature and strain rate could be formulated well by a hyperbolic-sinusoidal relationship using the Zener-Hollomon parameter.

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Low Cycle Fatigue Behaviour of AISI 304L Austenitic Stainless Steel Weldment (AISI 304L 오오스테나이트 스테인레스 강 용접부 의 Low Cycle Fatigue 거동에 관한 연구)

  • 김환태;황선효;남수우
    • Journal of Welding and Joining
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    • v.2 no.1
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    • pp.49-57
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    • 1984
  • The influence of weld defect, residual stress and microstructure on the Low Cycle Fatigue(L. C. F.) behaviour of AISI 304L austenitic stainless steel weldment has been studied. The specimens were welded by shielded metal are welding process, post weld heat treated(PWHT) at 900.deg.C for 1.5hrs, and tested under total strain controlled condition at room temperature. The results of the experiment showed that weld defect affected the L.C.F. behaviour of weldment deleteriously compared to the residual stress or microstructure, and it reduced the L.C.F. life about 70-80%. The PWHT exhibited beneficial effect on the L.C.F. behaviour and increased the L.C.F. life about 120%. This enhancement by PWHT was attributed to the removal of residual stress and recovery of weld metal ductility. The cyclic stress flow of as welded specimens showed intermediate cyclic softening, whereas those of heat treated specimens showed continuous cyclic hardening, and this difference was explained in terms of the residual stress removal and dislocation behaviour. Scanning electron microscopy studies of fatigue fracture surface showed that weld defects of large size and near weld surface were detrimental to the L.C.F. behaviour of weldment.

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The Effect of Light on Amorphous Silicon Thin Film Transistors based on Photo-Sensor Applications

  • Ha, Tae-Jun;Park, Hyun-Sang;Kim, Sun-Jae;Lee, Soo-Yeon;Han, Min-Koo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.953-956
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    • 2009
  • We have investigated the effect of light on amorphous silicon thin film transistors based photo-sensor applications. We have analyzed the instability caused by electrical gate bias stresses under the light illumination and the effect of photo-induced quasi-annealing on the instability. Threshold voltage ($V_{TH}$) under the negative gate bias stress with light illumination was more decreased than that under the negative gate bias stress without light illumination even though $V_{TH}$ caused by the light-induced stress without negative gate bias was shifted positively. These results are because the increase of carrier density in a channel region caused by the light illumination has the enhanced effect on the instability caused by negative gate bias stress. The prolonged light illumination led to the recovery of shifted VTH caused by negative gate bias stress under the light illumination due to the recombination of trapped hole charges.

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Vascular dysfunction in patients with type 2 diabetes mellitus

  • Ekta, Khandelwal;Mahaveer Jain;Sumeet Tripathi
    • Annals of Clinical Neurophysiology
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    • v.25 no.1
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    • pp.32-37
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    • 2023
  • Background: Type 2 diabetic mellitus (T2DM) is an emerging global pandemic which is associated with lots of co-morbidities and reported vascular dysfunctions. T2DM associated vascular dysfunctions leads to vasculopathy in the form of altered peripheral vascular dynamics. Cold stress test (CST) is a reliable sympathetic reactivity test used for assessing vascular dysfunctions. In this study we are trying to quantify vascular dysfunctions in T2DM patients non invasively by various parameters of photoplethysmography (PPG) of cold stress test. Methods: Case control study had done in referral health center AIIMS, Raipur. Parameters are recorded by finger-PPG before, during and after CST (1 min) in 2 groups, control (n = 20 healthy volunteers) and case (n = 20 diagnosed T2DM patients). Results: Due to cold stress, PPG parameter peak amplitude was significantly decreased in both healthy and T2DM groups (p <0.001 and p <0.001, respectively). However, recovery trend of amplitude was significantly slow in T2DM compared to healthy subjects. Another PPG parameter peak to peak interval was significantly higher in healthy group compared to T2DM patients. Conclusions: This study showed that T2DM patients has significant deranged pulse volume parameters like amplitude and peak to peak interval can be used to objectively quantify the vasculopathy in T2DM patients by using sympathetic reactivity to cold stress.

Analysis of Springback of Sheet Metal(I): Analytical Model Based on the Residual Differential Strain (박판재의 스프링백 해석(I)-잔류 변형율에 근거한 해석모델)

  • Lee, Jae-Ho;Kim, Dong-Woo;Sohn, Sung-Man;Lee, Mun-Yong;Moon, Young-Hoon
    • Transactions of Materials Processing
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    • v.16 no.7
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    • pp.509-515
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    • 2007
  • As the springback of sheet metal during unloading may cause deviation from a desired shape, accurate prediction of springback is essential for the design of sheet stamping operations. When considering the case of a sheet metal being bent to radius $\rho$ that is such that the maximum stress induced exceed the elastic limit of the material, plastic strain in the outer surface will occur and the material will take a permanent set: but since, on removing the bending moment, the recovery of the material is not uniform across the thickness, springback will occur and the radius $\rho$ will not be maintained. Furthermore, when a tensile load being applied to each end of specimen, the tensile stress due to bending is increased and the compressive stress is decreased or cancelled and eventually the whole specimen may be in varying degree of tension. On the removal of the applied load the specimen loses its elastic strain by contracting around the contour of the block, the radius $\rho$ will be determined by the residual differential strain. Therefore in this study the springback is analytically estimated by the residual differential strains between upper and lower surfaces of greatest radius after elastic recovery, and a springback model based on the bending moment is also analytically derived for comparison purpose.

Salt treatment for recovery of the mud loach, Misgurnus mizolepis from transport stress

  • Yu, Jin-Ha;Kim, Dae-Hyun;Han, Jung-Jo;Park, Sung-Woo
    • Korean Journal of Veterinary Research
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    • v.56 no.4
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    • pp.215-221
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    • 2016
  • Due to the shortage of the fingerling/juvenile mud loach, Misgurnus mizolepis in Korea, these fish have been imported from China. However, the mortality rate during and after their transportation is very high. In this study, we examined various physiological and histological parameters to evaluate the effect of salt treatment on the survival and recovery of mud loaches in holding farms during the quarantine process. Glucose, osmolality, $Na^+$, $Cl^-$, and histological changes were assessed for three different salinities. Non-treated fish (control 0.0%) exhibited lower levels of osmolality, and $Na^+$ and $Cl^-$ concentrations compared with those kept in solar salt solution (0.5% and 1.0%). Glucose levels in control fish were higher than those in fish exposed to 0.5% and 1.0% solar salt solution. Histologically, control fish showed thinner epidermis of skin, branchial hyperplasia and lamellar fusion with an abundance of eosinophilic granule cell-like cells. After solar salt solution treatment, damaged gill structures in the fish almost recovered within 5 days. The present study demonstrates that mud loaches transported from China suffer from skin and gill damage and physiological dysfunction which may increase the mortality and morbidity. Moreover, saline treatment might alleviate the stress responses and ionic/osmotic imbalances, and help heal gill damage.

Thermotolerance Inhibits Various Stress-induced Apoptosis in NIH3T3 Cells

  • Park, Jun-Eui;Lee, Kong-Joo;Kim, Choon-Mi
    • Archives of Pharmacal Research
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    • v.21 no.1
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    • pp.46-53
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    • 1998
  • When NIH3T3 cells were exposed to mild heat and recovered at $37^{\circ}C$ for various time intervals, they were thermotolerant and resistant to subsequent stresses including heat, oxidative stresses, and antitumor drug methotrexate which are apoptotic inducers. The induction kinetics of apoptosis by stresses were determined by DNA fragmentation and protein synthesis using $[35^S]$methionine pulse labeling. We investigated the hypothesis that thermotolerant cells were resistant to apoptotic cell death compared to control cells when both cells were exposed to various stresses inducing apoptosis. The cellular changes in thermotolerant cells were examined to determine which components are involved in this resistance. At first, the degree of resistance correlates with the extent of heat shock protein synthesis which were varied depending on the heating times at $45^{\circ}C$ and recovery times at $37^{\circ}C$after heat shock. Secondly, membrane permeability change was observed in thermotolerant cells. When cells prelabeled with $[^{3}H]$thymidine were exposed to various amounts of heat and recovered at $37^{\circ}C$ for 1/2 to 24 h, the permeability of cytosolic $[^{3}H]$thymidine in thermotolerant cells was 4 fold higher than that in control cells. Thirdly, the protein synthesis rates in thermotolerant and control cells were measured after exposing the cells to the same extent of stress. It turned out that thermotolerant cells were less damaged to same amount of stress than control cells, although the recovery rates are very similar to each other. These results demonstrate that an increase of heat shock proteins and membrane changes in thermotolerant cells may protect the cells from the stresses and increase the resistance to apoptotic cell death, even though the exact mechanism should be further studied.

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Expression of the Heat Shock Protein Genes in Response to Thermal Stress in the Silkworm Bombyx mori

  • Velu, Dhanikachalam;Ponnuvel, Kangayam. M.;Qadri, Syed. M. Hussaini
    • International Journal of Industrial Entomology and Biomaterials
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    • v.16 no.1
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    • pp.21-27
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    • 2008
  • The expression of heat shock protein genes (Hsp 70, Hsp 40, Hsp 20.8 and Hsp 20.4) against thermal stress in silkworm Bombyx mori was performed through semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Upon exposure of silkworm to two temperature regimes ($38^{\circ}C$ and $42^{\circ}C$), significant change in the expression of Hsp gene was observed as compared to the control. Hsp 70 and Hsp 40 showed increased expression than the small heat shock protein genes Hsp 20.8 and Hsp 20.4. The Hsp 70 showed increased expression during the recovery period as compared to 1 hr thermal treatments ($38^{\circ}C$/1 hr and $42^{\circ}C$/1 hr). Whereas, Hsp 40, Hsp 20.8 and Hsp 20.4 genes showed higher expression level at initial stages that later gradually decrease during recovery period. Tissue specific expression of Hsp 70 showed variation in the level of expression amongst the tissues. The mid gut and fat body tissues showed higher expression than the cuticle and silk gland tissue. The Hsp 70, Hsp 40 gene expression was analyzed in thermotolerant (Nistari) and thermo susceptible silk worm strain (NB4D2) and results showed significant variation in their expression level. The Nistari showed higher expression of Hsp 70 and Hsp 40 genes than the NB4D2. These findings provide a better understanding of cellular protection mechanisms against environmental stress such as heat shock, as these Hsps are involved in an organism thermotolerance.

Computational analysis of the electromechanical performance of mitral valve cerclage annuloplasty using a patient-specific ventricular model

  • Lee, Kyung Eun;Kim, Ki Tae;Lee, Jong Ho;Jung, Sujin;Kim, June-Hong;Shim, Eun Bo
    • The Korean Journal of Physiology and Pharmacology
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    • v.23 no.1
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    • pp.63-70
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    • 2019
  • We aimed to propose a novel computational approach to predict the electromechanical performance of pre- and post-mitral valve cerclage annuloplasty (MVCA). Furthermore, we tested a virtual estimation method to optimize the left ventricular basement tightening scheme using a pre-MVCA computer model. The present model combines the three-dimensional (3D) electromechanics of the ventricles with the vascular hemodynamics implemented in a lumped parameter model. 3D models of pre- and post-MVCA were reconstructed from the computed tomography (CT) images of two patients and simulated by solving the electromechanical-governing equations with the finite element method. Computed results indicate that reduction of the dilated heart chambers volume (reverse remodeling) appears to be dependent on ventricular stress distribution. Reduced ventricular stresses in the basement after MVCA treatment were observed in the patients who showed reverse remodeling of heart during follow up over 6 months. In the case who failed to show reverse remodeling after MVCA, more virtual tightening of the ventricular basement diameter than the actual model can induce stress unloading, aiding in heart recovery. The simulation result that virtual tightening of the ventricular basement resulted in a marked increase of myocardial stress unloading provides in silico evidence for a functional impact of MVCA treatment on cardiac mechanics and post-operative heart recovery. This technique contributes to establishing a pre-operative virtual rehearsal procedure before MVCA treatment by using patient-specific cardiac electromechanical modeling of pre-MVCA.