• Title/Summary/Keyword: cold exposure

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Experimental and Numerical Study of Fire Resistance of Composite Beams (무피복 합성보의 내화성능에 대한 실험 및 해석적 연구)

  • Ahn, Jae Kwon;Lee, Cheol Ho
    • Journal of Korean Society of Steel Construction
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    • v.27 no.2
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    • pp.143-153
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    • 2015
  • In this paper, the standard fire resistance test under load and associated numerical study were carried out to evaluate the fire resistance of unprotected partially encased beams and slimfloor beams. The temperature evolution and the deflection increase of the composite beam specimens were investigated and the effects of the key behavioral parameters including the load ratio, the reinforcement, and the fire exposure were analyzed. The test results showed that the temperature rise of the partially encased beams and slimfloor beams is considerably slow compared to the conventional H-shape composite beams. Up to at least 90 minutes, the reinforcements in the partially encased composite beams maintained below the temperature at which the cold steel strength is sustained. Unprotected partially encased beams and slimfloor beams in the experimental program achieved the fire resistance more than 2 hours according to the limiting deflection criteria. This implies that unprotected partially encased beams and slimfloor beams can be very promising alternatives to enhancing the fire resistance of steel beams. This study also conducted the fully coupled thermal-stress analysis by using the commercial code ABAQUS to the thermal and structural behaviour of composite beams in fire. The numerical predictions provide acceptable correlations with the experimental results.

Proposed Treatment Protocol for Frostbite: A Retrospective Analysis of 17 Cases Based on a 3-Year Single-Institution Experience

  • Woo, Eun-Kyung;Lee, Jong Wook;Hur, Gi-Yeun;Koh, Jang-Hyu;Seo, Dong-Kook;Choi, Jai-Ku;Jang, Young-Chul
    • Archives of Plastic Surgery
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    • v.40 no.5
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    • pp.510-516
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    • 2013
  • Background This paper discusses the treatment protocol for patients with frostbite. Methods We performed a retrospective analysis of a series of 17 patients with second- and higher-degree frostbite who had been treated at our medical institution between 2010 and 2012. Results Our clinical series of patients (n=17) included 13 men and four women, whose mean age was $42.4{\pm}11.6$ years (range, 22-67 years). The sites of injury include the foot in six patients (35.3%), the hand in six patients (35.3%) and the facial region in five patients (29.4%). Seven patients with second-degree frostbite were completely cured with only conservative treatment during a mean period of $12.7{\pm}3.3$ days (range, 8-16 days). Of the five patients with third-degree frostbite, two underwent skin grafting following debridement, and the remaining three achieved a complete cure with conservative treatment during a mean period of $35{\pm}4.3$ days (range, 29-39 days). Five patients with fourth-degree frostbite were treated with surgical procedures including amputation. Conclusions With the appropriate conservative management in the early stage of onset, surgeons should decide on surgery after waiting for a sufficient period of time until the demarcation of the wound. Continuous management of patients is also needed to achieve functional recovery after a complete cure has been achieved. This should also be accompanied by patient education for the avoidance of re-exposure to cold environments.

Temporal and Spatial Variations of Size-structured Phytoplankton in the Asan Bay (아산만 식물플랑크톤 크기구조의 시.공간적 변동)

  • Hyun Bong-Kil;Sin Yong-Sik;Park Chul;Yang Sung-Ryull;Lee Young-Joon
    • Korean Journal of Environmental Biology
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    • v.24 no.1 s.61
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    • pp.7-18
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    • 2006
  • Samples were collected from five stations monthly from October 2003 to September 2004 to investigate seasonal variation of size structure of phytoplankton and relationship between size-fractionated phytoplankton and environmental factors in the Asan Bay. The contribution of large cells (microphytoplankton, $>20\;{\mu}m$) to total concentrations of chlorophyll $\alpha$ was higher than small cells (nanophytoplankton, $3\sim20\;{\mu}m$; picophytoplankton, $<3\;{\mu}m$) during the sampling period. Especially, large cells contributed 80% to the total chlorophyll a from February, 2004 to April 2004 when chlorophyll $\alpha$ concentrations were high. The size structure of phytoplankton shifted from micro-size class to nano-size class and picophytoplankton rapidly increased when phytoplankton biomass decreased in May 2004. Microphytoplankton exhibited a high biomass in the upper region during winter-spring season whereas nano- and picophytoplankton showed two peaks in the middle-lower regions (Station 3,5) during spring and summer. Microphytoplankton are most likely controlled by water temperature and nutrient supply during the cold season whereas nano- and picophytoplankton may be affected by stratification, light exposure during the warm season.

Responses of Bacteria to TNT: Cells′Survival, SDS-PAGE and 2-D Electrophoretic Analyses of Stress-Induced Proteins (TNT에 대한 세균의 반응기작: 생존율, 스트레스 유도단백질의 SDS-PAGE 및 2-D 전기영동 분석)

  • 오계헌;장효원;강형일;김승일
    • Korean Journal of Microbiology
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    • v.38 no.2
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    • pp.67-73
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    • 2002
  • The cellular responses of soil-borne bacterium, Pseudomonas sp. HK-6 to explosive 2,4,6-trinitrotoluene (TNT) were examined. Two stress shock proteins (SSPs), approximately 70-kDa DnaK and a 60-kDa GroEL were found in HK-6 cells in response to TNT. Analyses of SDS-PAGE and Western blot using anti-DnaK and GroEL revealed that SSPs were induced in HK-6 cells exposed to 0.5 M of TNT far 6-12 hrs. The maximum induction of proteins was achieved at 8-hr incubation point after HK-6 cells'exposure to TNT. Similar SSPs were found to be induced in HK-6 cells by heat shock (shift of temperature, from $30^{\circ}C$ to $42^{\circ}C$) or cold shock (shift of temperature,$30^{\circ}C$ to $4^{\circ}C$).2D-PAGE of soluble protein tractions from the culture of Pseudomonas sp. HX-6 exposed to TNT demonstrated that approximately 450 spots were observed on the silver stained gels ranging from pH 3 to pH 10. Among them, 12 spots significantly induced and expressed in response to TNT were selected and analyzed. Approximately 60-kDa protein, which was assumed highly expressed on the gel, was used for amino acid sequencing. N-terminal microsequencing with in-gel digestion showed that N-terminal sequence of the TNT-induced protein, <$^1XXAKDVKFGDSARKKML^17$, shared extensive similarity with $^1XXAKDVKFGDSARKKML^17$, N-terminal sequence of (P48216) GroEL of Pseudomonas putida.

Introduction of Dental X-ray Imaging with New Concept - intra Oral x-ray Tube (신개념 치과용 X-선 영상장치 소개 - 강내형 X-선 튜브)

  • Cho, Sung-Ho;Kim, Dong-Young;Baek, Kwang-Woo;Lee, Re-Na
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.48 no.4
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    • pp.94-101
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    • 2011
  • Various kinds of medical imaging devices have been studied to develop periapical radiography. However, there are some problems such as high x-ray exposure rate and pains for patients because of the problems caused by intra-oral sensor based radiography system. In this study, a new concept of periapical radiography, intra oral X-ray tube and detector system, is introduced to solve these problems. This system is made up of miniature X-ray tube based on subminiature thermal electron or cold electron, CMOS based detector, and a body including automatic position and system control devices. In order to confirm the possibility of proposed new concept to periapical radiography, miniature x-ray tube from XOFT corporation is used to develop new x-ray system, and the performance evaluation of this system is performed according to collimator. Also, dental images are compared after acquiring both images from existing system versus new concept of system. As a result, new concept of system showed excellent image. Thus, it is considered that new concept of system will have a significant effect on medical imaging technology.

Thermal Insulation Effect of Inflatable Life Vest on the Drowned Individual estimated by Numerical Analysis (익수자 체온 저하에 미치는 팽창식 구명동의의 단열효과 수치 분석)

  • Kim, Sung Chan;Lee, Kyung Hoon;Hwang, Se Yun;Lee, Jin Sung;Lee, Jang Hyun
    • Journal of Navigation and Port Research
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    • v.39 no.4
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    • pp.285-291
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    • 2015
  • Exposure to cold sea water can be life-threatening to the drowned individual. Although appropriate life jacket can be usually be provided for the buoyance at the drowning accident, heat loss can make the drowned individual experience the hypothermia. Inflatable life jackets filled with inflatable air pocket can increase the thermal protection as well as the buoyancy force. Because it is important to know how the human body behaves unde the different life jacket, present study compares the thermal insulation capacity of solid type life jacket with that of inflatable life jacket. In order to represent the insulation capacity of life jacket, thermal resistance is estimated based on the assumption of steady-state. Also, a transient three-dimensional thermal distribution of the thigh is analyzed by using finite element method implementing the Pennes bioheat equation. The finite element model is a segmental, multi-layered representation of the body section which considers the heat conduction within tissue, bone, fat and local blood flow rate.

Clinical Studies on 254 Cases of Patient with Facial Paralysis (구안와사(口眼喎斜) 환자 254명에 대한 감리적(臨床的) 고찰(考察))

  • Ock, Min-Keun;Lim, Woong-Kyoung;Kim, Chang-Hwan;Park, Soo-Eun
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.18 no.3
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    • pp.75-83
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    • 2005
  • Objective: The purpose of this study is to investigate the clinical studies on 254 cases of patient with facial paralysis. Methods: We examined the sex, age, region, month, season, physical condition, attened symptoms, the period before admission, the period of treatment the times of treatment, the point of the recovery Results: 1. The distribution of sex was male 119 cases, female 125 cases(1.032:1). The distribution of age was disclosed that fifty was the most in 53 cases(20.9%) 2. In distribution of the region of facial palsy, the ratio of the male-left was 27.6%(70 cases), female-left was 24.4%(62cases), male-right was 23.2%(59 cases), female-right was 24.8%(63 cases). 3. In distribution of contributing frequence in month, January was the most in number(29 cases, 11.4%), In distribution of contributing number in season winter was the most in number(76 cases, 29.9%). 4. In distribution of physical condition, fatigue(99 cases, 40.0%), stress(66 cases 26.0%), cold exposure(43 cases, 16.9%) were investigated highly than other conditions. 5. In distribution of attended symptoms, stylomastoid pain(91 cases, 35.8%), tears(40 cases 15.7%). taste paralysis(29 cases, 11.4%) were investigated highly than other symptoms. 6. In distribution of the period before admission in descending order the first under the third day was the most number in 92 cases(62.2%), over two weeks 22 cases(14.9%) 7. In distribution of the period of treatment, over eight weeks was the most number in 91 cases(35.8%), under a week in 50 cases(19.7%). In distribution of the times of treatment under five times was the most number in 56 cases(14.2%). 8. In distribution of the point of the recovery, under two weeks was the most number in 77 cases(52%).

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The +1316 T/T Genotype in the Exon 3 of Uncoupling Protein Gene is Associated with Daily Percent Lay in Korean Native Chicken (한국 재래 닭의 Uncoupling Protein 유전자 Exon 3에서의 +1316 T/T 유전자형이 산란율에 미치는 효과 분석)

  • Oh J. D.;Lee J. H.;Hong Y. S.;Lee S. J.;Lee S. G.;Kong H. S.;Sang B. D.;Choi C. H.;Cho B. W.;Jeon G. J.;Lee H. K.
    • Korean Journal of Poultry Science
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    • v.32 no.4
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    • pp.239-244
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    • 2005
  • Uncoupling protein(UCP) is expressed exclusively in brown adipose tissue(BAT). It is blown to uncouple phosphorylation from oxidation and hence to be involved in energy metabolism and heat production, especially under cold exposure. In the present study, we identified single nucleotide polymorphism(SNP) in exon 3 of avUCP gene in Korean native chicken(KNC) population. It was detected a SNP T+1316C in exon 3 of avUCP gene by sequence analysis in KNC population. For PCR-RFLP analysis of the SNP T+1316C, used by AP III restriction enzyme. The result of PCR-RFLP analysis showed that allele T has two fragments of 255 bp and 86 bp, and allele C has only one fragment of 341 bp. The genotype frequencies were TT type, 0.7875; TC type, 0.1875 and CC type, 0.025; and the frequencies of allele T and C were 0.881 and 0.119, respectively in KNC population. Next study was conducted to investigate the effect of the SNP in avUCP gene on economic traits in the KNC population. The TT genotype had a significant higher daily percent lay(84.61) than CC genotype(p<0.05) in KNC population. This study may be useful for genetic studies of avCUP gene and selection on daily percent lay of KNC.

A SPECTROPHOTOMETRIC STUDY ON DISCOLORATION OF RESTORATIVE COMPOSITE RESINS IN COFFEE AND ARTIFICIAL SALIVA (분광광도계를 이용한 커피와 인공타액에서의 수복용 복합레진의 변색에 대한 연구)

  • Eom, Seung-Hee;Cho, Hyo-Sun;Lee, Chung-Sik
    • Restorative Dentistry and Endodontics
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    • v.21 no.2
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    • pp.530-545
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    • 1996
  • The purpose of this study was to investigate by spectrophotometry the changes in color parameters of composite resins after exposure to distilled water, filtered coffee, and artificial saliva. Five kinds of fine particle composite resin in experiment 1, and six kinds of composite resin in experiment 2 were used. In experiment 1, each group of composite resin was stored in distilled water at $4^{\circ}C$, $50^{\circ}C$, and filtered coffee solution at $4^{\circ}C$, $50^{\circ}C$. And then each specimen was measured by spectrophotometer. Measurements were repeated in 1 hour, 2 hours, 4 hours, 8 hours, 16 hours, 24 hours, and 48 hours. In experiment 2, all specimens of each brand were stored in distilled water at $37^{\circ}C$, artificial saliva not contained mucin at $37^{\circ}C$, and artificial saliva contained mucin at $37^{\circ}C$. All specimens of each brand were measured by spectrophotormeter in 1 week, 2 weeks, 4 weeks, 8 weeks, and up to 12 weeks. The results were as follows : 1. In cold coffee, five of fine particle composite resins showed ${\Delta}E{^*}_{ab}$ values less than 2. However, in hot coffee ${\Delta}E{^*}_{ab}$ values of Amelogen Universal and Prisma TPH were higher than those of Conquest Crystal, ${\AE}$litefil and Z100. 2. Z100 and ${\AE}$litefil had better cleansibility of extrinsic coffee staining than Amelogen Universal, Conquest Crystal and Prisma TPH. 3. In distilled water and artificial saliva not contained mucin, five of fine particle composite resin showed ${\Delta}E{^*}_{ab}$ values less than 2 up to 12 weeks. However, Silux Plus showed higher than ${\Delta}E{^*}_{ab}$ values of fine particle composite resin. 4. As an immersion solution for discoloration experiment, artificial saliva not contained mucin showed similar appearance as distilled water. However, artificial saliva contained mucin had different appearance from the others. 5. In artificial saliva contained mucin, ${\AE}$litefil, Prisma TPH and Z100 showed ${\Delta}E{^*}_{ab}$ values less than 1 up to 12 weeks. However, Silux Plus, Amelogen Universal and Conquest Crystal showed ${\Delta}E{^*}_{ab}$ values more than 1 up to 12 weeks. But, Conquest Crystal showed different characteristics of chromacity difference value(less chromatic) and lightness difference value(lighter) from Silux Plus and Amelogen Universal.

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Exposure to Atmospheric Particulates and Associated Respirable Deposition Dose to Street Vendors at the Residential and Commercial Sites in Dehradun City

  • Prabhu, Vignesh;Gupta, Sunil K.;Madhwal, Sandeep;Shridhar, Vijay
    • Safety and Health at Work
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    • v.10 no.2
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    • pp.237-244
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    • 2019
  • Background: Street vendors spend relatively more time near roadways and are vulnerable to air pollution related health disorders. However, there is limited information on the quality of the air they breathe. The objectives of this present study were to calculate the mass concentration of atmospheric particulate matter (PM) in eight size fractions ($PM_{0.4-0.7}$, $PM_{0.7-1.1}$, $PM_{1.1-2.1}$, $PM_{2.1-3.3}$, $PM_{3.3-4.7}$, $PM_{4.7-5.8}$, $PM_{5.8-9.0}$, and $PM_{9.0--0{\mu}m}$) at commercial (CML) and residential site (RSL) in Dehradun city from November 2015 to May 2016. To estimate the corresponding respiratory deposition dose (RDDs) in alveolar (AL), tracheobronchial (TB), and head airway (HD) region on street vendors working at CML and RSL. To find the association of atmospheric PM with RDDs and the incidence of respiratory related disorders among street vendors. Methods: Andersen cascade impactor was employed for calculating the PM mass concentration. Questionnaire based health survey among street vendors were carried out through personal interview. Results: A significant difference (p < 0.05; t-test) between the mean $PM_{0.4-10{\mu}m}$ mass concentration at CML and RSL was observed with ($mean{\pm}SD$) $84.05{\pm}14.5$ and $77.23{\pm}11.7{\mu}g\;m^{-3}$, respectively. RDDs in AL, TB and HD region at CML was observed to be 9.9, 7.8, and 7.3% higher than at RSL, respectively. Health survey revealed 1.62, 0.96, 0.04, and 0.57 times higher incidence of cold, cough, breathlessness, and chest pain, respectively with street vendors at CML compared to RSL. Conclusion: The site characteristics plays a major role in the respiratory health status of street vendors at Dehradun.