• 제목/요약/키워드: cold exposure

검색결과 184건 처리시간 0.029초

Lack of Sunlight Exposure Influence on Primary Glioblastoma Survival

  • Mutlu, Hasan;Akca, Zeki;Erden, Abdulsamet;Aslan, Tuncay;Ucar, Kadir;Kaplan, Bunyamin;Buyukcelik, Abdullah
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권10호
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    • pp.4165-4168
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    • 2014
  • Background: The prognosis of primary glioblastoma (GBM) is poor. Approximately 2/3 of primary brain tumor diagnoses are GBM, of which 95% are primary lesions. In this study, we aimed to evaluate whether more sunlight exposure has an effect on survival of patients with primary GBM. Materials and Methods: A total of 111 patients with primary GBM were enrolled from Kayseri in inner Anatolia which has a cold climate (n: 40) and Mersin in Mediterranean region with a warm climate and more sunlight exposure (n: 71). The patients with primary GBM were divided into two groups as Kayseri and Mersin and compared for progression free survival (PFS) and overall survival (OS).Results: The PFS values were 7.0 and 4.7 months for Kayseri and Mersin groups, respectively (p=0.10) and the repsective OS values were 13.3 and 9.4 months (p=0.13). We did not found any significant difference regarding age, sex, comorbidity, smoking, surgery, resurgery, adjuvant chemoradiotherapy and palliative chemotherapy between the groups. Conclusions: We found that more sunlight exposure had no impact on prognosis of patients with primary GBM, adding inconsistency to the literature about the relationship between sunlight and GBM.

배추좀나방 월동 조건과 야외 월동집단의 유전적 변이 (Overwintering Conditions of the Diamondback Moth and Genetic Variation of Overwintering Populations)

  • 김은성;최봉기;박영진;차욱현;정충렬;이대원;김광호;김용균
    • 한국응용곤충학회지
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    • 제53권4호
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    • pp.355-365
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    • 2014
  • 배추좀나방(Plutella xylostella)이 국내에서 월동이 가능한 지 명확하지 않았다. 본 연구는 배추좀나방의 내한성에 기초한 야외 노출 실험을 실시하여 월동 환경 조건을 결정하고, 동계 야외 지역의 배추좀나방 유충 서식지 관찰 및 성페로몬을 이용한 성충 모니터링을 통해 월동이 가능한 지 조사하였다. 또한 이들 월동집단의 유래를 추적하기 위해 다형유전좌위를 이용한 집단 분석을 실시하였다. 배추좀나방의 체내빙결점 보다 높은 $-5^{\circ}C$로 처리한 결과 모든 미성숙 발육태에서 뚜렷한 생존력 저하를 보여 직접적 냉해 피해를 주었다. 여기서 유충발육태는 가장 낮은 냉해 피해를 받았다. 그러나 $5^{\circ}C$로 장기간(4 주) 처리한 결과 냉해 피해는 없었지만, 유충의 경우 먹이가 없는 상태에서 치사율이 증가했다. 모든 발육태의 배추좀나방을 대상으로 겨울 기간 동안 야외조건에 노출시킨 결과 모든 발육태에서 생존력 저하를 나타냈다. 그러나 비가온 실내조건에서 저온 피해를 줄였으며 유충의 경우 먹이가 공급되면 생존력이 뚜렷하게 증가하였다. 동계 성페로몬 모니터링 결과 2014년도 최초의 성충발생일은 유사한 시기에 서로 다른 지역(약 260 Km 거리)에서 나타났으며 월동집단의 성충은 4월 상순까지 포획되었다. 지역간 이들 월동집단의 유전적 거리는 다형분자마커를 이용하여 분석되었으며 이들 월동집단들 사이에 뚜렷한 유전적 분화가 있는 것을 나타냈다. 본 연구는 배추좀나방의 국내 월동이 남쪽 지역 또는 기주 식물이 있는 시설재배지에서 가능한 것으로 제시하고 있다.

Susceptibility of rat hippocampal neurons to hypothermia during development

  • Seo, Kyung Ah;Kim, Sehhyun;Lee, Na Mi;Chae, Soo Ahn
    • Clinical and Experimental Pediatrics
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    • 제56권10호
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    • pp.446-450
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    • 2013
  • Purpose: This study evaluated the extent of damage due to hypothermia in the mature and immature brain. Methods: Hippocampal tissue cultures at 7 and 14 days in vitro (DIV) were used to represent the immature and mature brain, respectively. The cultures were exposed at $25^{\circ}C$ for 0, 10, 30, and 60 minutes (n=30 in each subgroup). Propidium iodide fluorescent images were captured 24 and 48 hours after hypothermic injury. Damaged areas of the cornu ammonis 1 (CA1), CA3, and dentate gyrus (DG) were measured using image analysis. Results: At 7 DIV, the tissues exposed to cold injury for 60 minutes showed increased damage in CA1 (P<0.001) and CA3 (P=0.005) compared to the control group at 48 hours. Increased damage to DG was observed at 24 (P=0.008) and 48 hours (P=0.011). The 14 DIV tissues did not demonstrate any significant differences compared with the control group, except for the tissues exposed for 30 minutes in which DG showed less damage at 48 hours than the control group (P=0.048). In tissues at 7 DIV, CA1 (P=0.040) and DG (P=0.013) showed differences in the duration of cold exposure. Conclusion: The immature brain is more vulnerable to hypothermic injury than the mature brain.

양생온도 변화 및 버블시트 두께변화에 따른 콘크리트의 온도이력특성 (Temperature History of Concrete Corresponding to Various Bubble Sheets Layer and Curing Temperature)

  • 홍석민;백대현;한민철;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2008년도 추계 학술논문 발표대회
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    • pp.21-25
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    • 2008
  • In this paper, the temperature history and the strength development of concrete corresponded to various bubble sheets layer and curing temperature. Based on the results, In case of the test temperature of -5℃, concrete subject in the exposure condition, result in a frost damage at initial stage by a fall of below zero temperature. In case of the combination of PE film and non woven fabric was after 36 hour, and combination of bubble sheet over double, a tremendous insulating effect of bubble sheet over double is confirmed due to the temperature of concrete fall of below zero temperature after 60 hours. Meanwhile, regarding the -15℃ of temperature, special measure for insulation curing is necessary to secure stability against early frost damage because frost damage was not affected by the lapping thickness of bubble sheet subjected to severe cold weather condition.

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Delayed-type retrobulbar hematoma caused by low temperature after reconstruction of inferior blow-out fracture

  • Lee, Da Woon;Kim, Tae Hyung;Choi, Hwan Jun;Wee, Syeo Young
    • 대한두개안면성형외과학회지
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    • 제22권2호
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    • pp.110-114
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    • 2021
  • Retrobulbar hemorrhage is a disastrous condition that can lead to permanent blindness. As such, rapid diagnosis and treatment are critical. Here, we report a patient who presented with retrobulbar hemorrhage following an orbital floor fracture. Restoration of inferior orbital wall with porous polyethylene implant was underwent. Four days after the orbital floor reconstruction, the patient smoked a cigarette outdoors in -3℃ weather. Cold temperature and smoking caused an increase in his systemic blood pressure. The elevated blood pressure increased intraorbital pressure to the extent of causing central retinal artery occlusion and exacerbated oozing. During exploratory surgery, 3 mL of hematoma and diffuse oozing without arterial bleeding were observed. Prompt diagnosis and treatment prevented vision impairment. Few studies have reported on the risk factors for retrobulbar hemorrhage. This case showed that daily activities, such as exposure to cold weather or tobacco smoking, could be risk factors for retrobulbar hemorrhage.

Effect of Ice accretion on the aerodynamic characteristics of wind turbine blades

  • Sundaresan, Aakhash;Arunvinthan, S.;Pasha, A.A.;Pillai, S. Nadaraja
    • Wind and Structures
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    • 제32권3호
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    • pp.205-217
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    • 2021
  • Cold regions with high air density and wind speed attract wind energy producers across the globe exhibiting its potential for wind exploitation. However, exposure of wind turbine blades to such cold conditions bring about devastating impacts like aerodynamic degradation, production loss and blade failures etc. A series of wind tunnel tests were performed to investigate the effect of icing on the aerodynamic properties of wind turbine blades. A baseline clean wing configuration along with four different ice accretion geometries were considered in this study. Aerodynamic force coefficients were obtained from the surface pressure measurements made over the test model using MPS4264 Simultaneous pressure scanner. 3D printed Ice templates featuring different ice geometries based on Icing Research Tunnel data is utilized. Aerodynamic characteristics of both the clean wing configuration and Ice accreted geometries were analysed over a wide range of angles of attack (α) ranging from 0° to 24° with an increment of 3° for three different Reynolds number in the order of 105. Results show a decrease in aerodynamic characteristics of the iced aerofoil when compared against the baseline clean wing configuration. The key flow field features such as point of separation, reattachment and formation of Laminar Separation Bubble (LSB) for different icing geometries and its influence on the aerodynamic characteristics are addressed. Additionally, attempts were made to understand the influence of Reynolds number on the iced-aerofoil aerodynamics.

한냉에 노출된 인체의 냉각과 총지방량 및 S/V 비율 사이의 관계 (Relationship between Total Body Fat and S/V Ratio and Body Cooling for Two Hours at $15^{\circ}C$)

  • 정관옥;남기용
    • The Korean Journal of Physiology
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    • 제3권1호
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    • pp.19-28
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    • 1969
  • Skin temperatures on 10 sites and rectal temperature at every 10 minutes, oxygen consumption at every 20 minutes were measured on 18 male subjects (ages between 14 and 47 years) after exposure to cold air at $15^{\circ}C$ for two hours in a climatic room. Total body fat measured by means of a skinfold method and ratio of body surface area (S) to body volume (V), S/V, were utilized as basis of observations. Surface area was calculated after DuBois equation and body volume was calculated by our original formula. In influencing on the heat loss from the body core to the cold environment, % fat showed inverse relations, whereas, S/V ratio showed direct relations. Thus these two factors acted antagonistically on the body heat loss. Local skin temperatures showed negative correlations with skinfold thickness on the same site, nemaly, on chest, r=-.567; on back, r=-.507; and on upper arm, r=-.353. The other 7 skin sites showed low correlations with % fat. Minimum mean weighted skin temperature (MWST) showed a negative correlation (r=-.443) with % fat, and showed no correlation with S/V ratio. Oxygen consumption in the cold air at $15^{\circ}C$ increased from the first measurement at 20 minutes after exposure and maintained the same increasing trend up to 120 minutes. ${\Delta}T_R$ was greater in tile lean subjects who showed a greater % change in oxygen consumption. The antagonistic actions of % fat and S/V ratio on the heat loss were manifested by observations as follows: minimum rectal temperature was higher In fat subjects (r=.600) and lower in subjects with a greater S/V ratio (=-.582), ${\Delta}T_R$ was smaller in fat subjects (r=-.738) and greater in subjects with a greater S/V ratio (r=.618). Temperature difference between body core and skin surface (minimum rectal temperature minus minimum MWST) showed a positive correlation with % fat (r=.600) and a negative correlation with S/V ratio (r=-.881). Decrease in the mean body temperature and heat debt, respectively, showed negative correlations with % fat and positive correlations with S/V ratio.

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Being a front-line dentist during the Covid-19 pandemic: a literature review

  • Fallahi, Hamid Reza;Keyhan, Seied Omid;Zandian, Dana;Kim, Seong-Gon;Cheshmi, Behzad
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제42권
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    • pp.12.1-12.9
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    • 2020
  • Coronavirus is an enveloped virus with positive-sense single-stranded RNA. Coronavirus infection in humans mainly affects the upper respiratory tract and to a lesser extent the gastrointestinal tract. Clinical symptoms of coronavirus infections can range from relatively mild (similar to the common cold) to severe (bronchitis, pneumonia, and renal involvement). The disease caused by the 2019 novel coronavirus (2019-nCoV) was called Covid-19 by the World Health Organization in February 2020. Face-to-face communication and consistent exposure to body fluids such as blood and saliva predispose dental care workers at serious risk for 2019-nCoV infection. As demonstrated by the recent coronavirus outbreak, information is not enough. During dental practice, blood and saliva can be scattered. Accordingly, dental practice can be a potential risk for dental staff, and there is a high risk of cross-infection. This article addresses all information collected to date on the virus, in accordance with the guidelines of international health care institutions, and provides a comprehensive protocol for managing possible exposure to patients or those suspected of having coronavirus.

레이노드 증후군의 치료에 있어서 수부 교감신경절제술 (Digital Sympathectomy for Treatment of Raynaud's Syndrome)

  • 이세환;안희창;최승석;김창연
    • Archives of Plastic Surgery
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    • 제32권4호
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    • pp.479-484
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    • 2005
  • Raynaud's syndrome causes discolorization, ischemic claudication(pain) and necrosis of the digits through insufficiency in the circulation which is induced by intermittent spasms of the digital arteries. From January, 2002 to December, 2004, 10 patients were surgically treated for Raynaud's syndrome. 9 patients were female and 1 patient was male. 2 patients showed unilateral involvement, 8 patients were operated on both hands. 6 patients had necrotic changes on the finger tips due to the disease. Ages ranged from 21 to 60 with an average of 39.1. Ischemic pain, discolorization, and cold intolerance of the digits were the common symptoms. All patients were evaluated with color doppler before the surgery. Two different procedures were applied according to the severity of the disease: Patients with decreased circulation received, what we call a limited digital sympathectomy, i.e. stripping of the adventitia of the ulnar, radial and common digital arteries. An extended procedure, radical digital sympathectomy, was performed on patients with a complete block of circulation. Stripping of the adventitia in these patients also involved the proper digital arteries. Symptoms like discolorization, ischemic pain, and cold intolerance improved immediately after the surgery. The patients did not suffer from pain even with exposure to cold weather. We conclude that digital sympathectomy could improve the symptoms in Raynaud's patients who do not respond to conservative treatment such as calcium channel blocker and other vasodilators.

저온 Plasma를 이용한 Poly(ethylene terephthalate)에의 Acrylic Acid의 기상 Graft 공중합 반응(I) (The Graft Polymerization of Acrylic Acid in Vapour Phase onto Poly(ethylene terephthalate) by Cold Plasma Part (I))

  • 천태일;최석철;모상영
    • 한국염색가공학회지
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    • 제1권1호
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    • pp.7-18
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    • 1989
  • The distinguishing characteristic of the glow discharge is that chemical reaction induced by partially ionized gases are limited only to the substrate surface. Most studies have been done on the plasma etching and polymerization. The graft polymerization in vapour phase by cold plasma has been rarely investigated. In this study the system of tub3ar reaction chamber with capacitively coupled electrode of alternative current of 60 Hz was employed for the graft polymerization. The graft polymerization of Acylic Acid(AA) onto the poly (ethylene terephthalate) (PET) was carried out by treatment of PET film and fabric by cold plasma (glow discharge of argon gas), followed by the supply of AA vapour. The graft yield was about 1 wt%. The surface property was determined by contact angle, the surface tension was evaluated by zisman’s plot and equation of surface tension mesurement. The results were as follows: 1. In order to obtain lower contact angle, it was effective to avoid the vicinity of electrodes for a setting position of substrate. 2. Contact angle affected on the monomer pressure and its duration of exposure to the acid vapour. 3. Polymer radical formation was influenced by the changes of the value of current density and plasma treatment time. 4. Total surface tension of plasma grafted PET film increased. With an increase in the carboxylic acid content, the dispersion force decreased, while, the polar force and hydrogen bonding force increased. 5. The contact angle decreased from $75^\circ$ to around $30^\circ$ by plasma grafting. There was no ageing effect on the contact angle after 4 months.

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