• 제목/요약/키워드: structural alterations

검색결과 125건 처리시간 0.031초

Histological Responses of the Antarctic Bivalve Laternula elliptica to a Short-term Sublethal-level Cd Exposure

  • Choi, Hee-Seon, J.;Ahn In-Young;Lee, Yong-Suk;Kim, Ko-Woon;Jeong, Kye-Heon
    • Ocean and Polar Research
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    • 제25권2호
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    • pp.147-154
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    • 2003
  • To develop fast and sensitive biomarkers for metal exposures in Antarctic marine organisms we examined histological alterations of an Antarctic sentinel bivalve species Laternula elliptica following a short-term exposure to a sublethal-level of Cd. Distinct histological alterations of tissues and cells of the gills, kidneys, and digestive glands were observed after 8-to 16-hours of exposure to Cd while an increase of Cd concentrations in tissues was not detectable. Most alterations were highly localized in the epithelium of the three tissues; epithelia were found to be detached from the remaining tissue parts. In addition ultra-structural changes such as cytosolic vacuolization, dilation of nucleus and rER membranes were detected in all three tissues, which suggested that the clams are subject to sublethal stresses. Thus, histological and ultrastructural changes on localized tissue parts were rapid and sensitive, suggesting that they may serve biomarkers for Cd exposures. Linkages between the shown ulrastructural changes and higher biological organization level responses are to be established by longer-term exposure experiments.

도시 가구의 주거 과밀 지각과 주거 적응 행동에 관한 연구 (Residential Crowding and Adoptation Behavior of the Urban Households)

  • 문숙재;이경희
    • 가정과삶의질연구
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    • 제4권1호
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    • pp.109-125
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    • 1986
  • In recent years, conoeptualizations of the residential crowding phenomena have developed form deterministic approaches to functionalistic ones which emphasize the interaction of environmental , social, and personal variables. The influences of each variables which are believed to mediate the crowding perception have been tested. This study examines the association of the influence of socio-demographic variables, residential setting and previous residential experience with the residential crowding. Futhermore, the residential adoptation behavior in response to the crowding phenomena is analyzed. The results of a survey are as follows; 1)The most important variables which influence residential crowding are the residential setting variables such as the floor space and the measure of persons per room. Also the household income and the family structure influence the residential crowding. No previous residential experience effects were found. 2)The residential adoptation behavior is influenced by sex, age and socio-economic status of the family. Female and the age group of 20s and 30s tend to prefer such alternatives as moving or residential alterations and additions. On the other hand, male and the age group of 40s and 50s tend to prefer staying without nay alternatives or structural family adoptation. The group of higher socio- economic status tend to show higher preference to moving and alterations, and the lower ones tend to stay or take the alternative of the structural family adoptation. Years of education and the family structure do not influence the residential adopation behavior.

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Vascular health late after Kawasaki disease: implications for accelerated atherosclerosis

  • Cheung, Yiu-Fai
    • Clinical and Experimental Pediatrics
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    • 제57권11호
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    • pp.472-478
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    • 2014
  • Kawasaki disease (KD), an acute vasculitis that primarily affects young children, is the most common acquired paediatric cardiovascular disease in developed countries. While sequelae of arterial inflammation in the acute phase of KD are well documented, its late effects on vascular health are increasingly unveiled. Late vascular dysfunction is characterized by structural alterations and functional impairment in term of arterial stiffening and endothelial dysfunction and shown to involve both coronary and systemic arteries. Further evidence suggests that continuous low grade inflammation and ongoing active remodeling of coronary arterial lesions occur late after acute illness and may play a role in structural and functional alterations of the arteries. Potential importance of genetic modulation on vascular health late after KD is implicated by associations between mannose binding lectin and inflammatory gene polymorphisms with severity of peripheral arterial stiffening and carotid intima-media thickening. The changes in cholesterol and lipoproteins levels late after KD further appear similar to those proposed to be atherogenic. While data on adverse vascular health are less controversial in patients with persistent or regressed coronary arterial aneurysms, data appear conflicting in individuals with no coronary arterial involvements or only transient coronary ectasia. Notwithstanding, concerns have been raised with regard to predisposition of KD in childhood to accelerated atherosclerosis in adulthood. Until further evidence-based data are available, however, it remains important to assess and monitor cardiovascular risk factors and to promote cardiovascular health in children with a history of KD in the long term.

세라믹 가공 장비(MCT)의 구조 안정화 설계 (Stability Design of a Machining Center for Ceramic Materials)

  • 윤재훈;한대성;윤현진;이일환
    • 반도체디스플레이기술학회지
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    • 제18권3호
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    • pp.133-139
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    • 2019
  • The utilizations of ceramics in the modern industries are increasing due to the desirable combinations of electrical, mechanical and physical properties found in ceramics. Ceramic materials are brittle, hard, strong in compression, weak in shearing and tension which is prone to affect the defects such as scratch, crack and breakage during the machining. Generally, the defects of the ceramic machining are generated from the structural vibrations of the machine. In this study, the dynamic characteristics of a machining center for ceramic machining were investigated to analyze the structural vibrations for the improved stability. Frequency response test and computer simulation have been conducted for the analysis and the design improvement. The improved design is suggested to suppress vibrations for the higher stability of the machine and further to reduce vibrations. And the result shows that simple design alterations without any change of major parts of the machine can reduce the vibration of the machine effectively.

가공 제품 품질 향상을 위한 면취장비의 설계 개선 (Design Alterations of a Chamfering Machine Structure for the Improved Surface Quality)

  • 이일환;노승훈;한대성;김영조;길사근;박인규
    • 반도체디스플레이기술학회지
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    • 제18권1호
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    • pp.117-122
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    • 2019
  • Pipes are widely used in various industries such as automobile, anti-vibration devices, factories and ship building. Chamfering is one of the most critical processes in pipe manufacturing which removes burrs of the pipes for better surface quality. In most cases, the defects of the chamfered surface are originated from the structural vibrations of the chamfering machine. In this study, the dynamic characteristics of a chamfering machine have been analyzed though the experiment and the computer simulation. And the effects of the design parameters affecting the stability of the machine have been investigated to stabilize the machine structure and further to reduce structural vibrations. The result shows that design alterations to stabilize the machine can suppress the defects of the machined surface as well as the vibrations during chamfering.

In-silico and structure-based assessment to evaluate pathogenicity of missense mutations associated with non-small cell lung cancer identified in the Eph-ephrin class of proteins

  • Shubhashish Chakraborty;Reshita Baruah;Neha Mishra;Ashok K Varma
    • Genomics & Informatics
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    • 제21권3호
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    • pp.30.1-30.13
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    • 2023
  • Ephs belong to the largest family of receptor tyrosine kinase and are highly conserved both sequentially and structurally. The structural organization of Eph is similar to other receptor tyrosine kinases; constituting the extracellular ligand binding domain, a fibronectin domain followed by intracellular juxtamembrane kinase, and SAM domain. Eph binds to respective ephrin ligand, through the ligand binding domain and forms a tetrameric complex to activate the kinase domain. Eph-ephrin regulates many downstream pathways that lead to physiological events such as cell migration, proliferation, and growth. Therefore, considering the importance of Eph-ephrin class of protein in tumorigenesis, 7,620 clinically reported missense mutations belonging to the class of variables of unknown significance were retrieved from cBioPortal and evaluated for pathogenicity. Thirty-two mutations predicted to be pathogenic using SIFT, Polyphen-2, PROVEAN, SNPs&GO, PMut, iSTABLE, and PremPS in-silico tools were found located either in critical functional regions or encompassing interactions at the binding interface of Eph-ephrin. However, seven were reported in nonsmall cell lung cancer (NSCLC). Considering the relevance of receptor tyrosine kinases and Eph in NSCLC, these seven mutations were assessed for change in the folding pattern using molecular dynamic simulation. Structural alterations, stability, flexibility, compactness, and solvent-exposed area was observed in EphA3 Trp790Cys, EphA7 Leu749Phe, EphB1 Gly685Cys, EphB4 Val748Ala, and Ephrin A2 Trp112Cys. Hence, it can be concluded that the evaluated mutations have potential to alter the folding pattern and thus can be further validated by in-vitro, structural and in-vivo studies for clinical management.

서울지역 아파트의 규모별 실내디자인 리모델링에 대한 심층 사례 연구 (A Case Study on the Interior Design Remodeling of Apartment according to the Floors Space in Seoul)

  • 신경주;이지영;장상옥
    • 한국주거학회논문집
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    • 제16권2호
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    • pp.1-10
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    • 2005
  • The purpose of this study is providing useful information for consumer-friendly house plan by investigating remodeling apartments according to the area type and size. In order to achieve this aim, case study was applied. The case study was conducted of five small, medium, and large size apartments through depth-interviews, actual survey, and questionnaires on the remodeling behavior, interior design, and interior atmosphere. The results of the study are as follows: Structural alterations were frequent in communal area, and then in private and household areas. Changing lighting fixtures was frequent in all area types, and especially, in communal areas installing extra decoration was frequently observed. Besides, alterations of doors and window frames were carried out in communal, private, housework and service areas by using wood, aluminum sashes, double-glazing, and paint coating. Finally, in housework areas the material and color of counters were changed into wooden and achromatic.

일체형 컴퓨터의 구조 안정화를 위한 설계 개선 (Design Alteration of a All in One PC for the Improved Stability)

  • 김동욱;노승훈;김건형;양용준
    • 한국기계가공학회지
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    • 제12권6호
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    • pp.109-116
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    • 2013
  • Vibrations are generally recognized as the biggest concern in maintaining part' longevity of an All-in-one PC. The vibrations in PCs originate from excitation sources such as the HDD and the cooling fan. In this study, the vibrations from these sources were investigated in order to analyze the individual effects of the parameters on the structural vibrations of the PC; further, we attempted to establish design alterations that could successfully suppress vibrations, in order to achieve improved stability and part' longevity. The results show that relatively simple design alterations can substantially improve the stability of PCs.

공작기계의 진동억제를 위한 설계개선 효과 (Effects of Design Alterations on the Vibration Suppression of a Machine Tool Structure)

  • 김영조;노승훈;신호범;신윤호;정근섭;남규동
    • 한국기계가공학회지
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    • 제15권3호
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    • pp.122-129
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    • 2016
  • In modern industries, in whichwhere high productivity is one of the most important concerns, machine tools are facing difficulties to satisfy the high high-speed operation, while and at the same time achieve the precision machining. Generally, the vibrations of the structure increase proportionally to the square of the operating speed so that the precision machining is severely damaged with increased speed. which is a must for the high productivity. Therefore, the suppression of the structural vibrations of the machine tools is the a major concern in the machine tool industry in order to achieve the high productivity and the precision machining simultaneously. In this study, the dynamic properties of a machining center structure were analyzed through the experiment and the computer simulations, and furthermore the results from those were compared to confirm the validity of the simulation model. The design alterations were deduced from the analysis and applied to the simulation model to investigate the effects of those alterations to suppress the vibrations of the machine. The result shows that the relatively simple design alterations, without redesigning the main structure of the machine, can suppress the vibrations effectively.

Imipramine Ameliorates Depressive Symptoms by Blocking Differential Alteration of Dendritic Spine Structure in Amygdala and Prefrontal Cortex of Chronic Stress-Induced Mice

  • Leem, Yea-Hyun;Yoon, Sang-Sun;Jo, Sangmee Ahn
    • Biomolecules & Therapeutics
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    • 제28권3호
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    • pp.230-239
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    • 2020
  • Previous studies have shown disrupted synaptic plasticity and neural activity in depression. Such alteration is strongly associated with disrupted synaptic structures. Chronic stress has been known to induce changes in dendritic structure in the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC), but antidepressant effect on structure of these brain areas has been unclear. Here, the effects of imipramine on dendritic spine density and morphology in BLA and mPFC subregions of stressed mice were examined. Chronic restraint stress caused depressive-like behaviors such as enhanced social avoidance and despair level coincident with differential changes in dendritic spine structure. Chronic stress enhanced dendritic spine density in the lateral nucleus of BLA with no significant change in the basal nucleus of BLA, and altered the proportion of stubby or mushroom spines in both subregions. Conversely, in the apical and basal mPFC, chronic stress caused a significant reduction in spine density. The proportion of stubby or mushroom spines in these subregions overall reduced while the proportion of thin spines increased after repeated stress. Interestingly, most of these structural alterations by chronic stress were reversed by imipramine. In addition, structural changes caused by stress and blocking the changes by imipramine were corelated well with altered activation and expression of synaptic plasticity-promoting molecules such as phospho-CREB, phospho-CAMKII, and PSD-95. Collectively, our data suggest that imipramine modulates stress-induced changes in synaptic structure and synaptic plasticity-promoting molecules in a coordinated manner although structural and molecular alterations induced by stress are distinct in the BLA and mPFC.