• Title/Summary/Keyword: long term effects

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Comparative Study on the Viability of Frozen-thawed Primordial Germ Cells using Vitrification in Chicken Breed (초자화 동결법을 이용한 닭 품종간의 원시생식세포 동결성적의 비교)

  • Kim, Hyun;Kim, Dong Hun;Han, Jae Yong;Choi, Sung Bok;Ko, Yeoung Gyu;Do, Yoon Jung;Seong, Hwan Hoo;Kim, Sung Woo
    • Korean Journal of Poultry Science
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    • v.40 no.3
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    • pp.207-216
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    • 2013
  • This study was conducted to establish the method for preserving PGCs that enables long-term storage in liquid nitrogen for developmental engineering or preservation of species. The purpose of this study is to clarify the effects of freeze-thaw treatment on viability of PGCs in chickens. PGCs were collected separately from a germinal gonad of an early embryo of 5.5~6 day (stage 28) of Isa brown, Korean Oge (KO), White Leghorn and Commercial breeds. PGCs separated from a germinal gonad of an early embryo of 5.5~6 day (stage 28) are suspended in a freezing medium containing a freezing and protecting agents (e.g. dimethyl sulfoxide (DMSO), ethylene glycol (EG) and glycerol). The PGCs were then purified using magnetic activated cell sorting (MACS) method. The viability of PGCs after thawing was $87.4{\pm}0.4%$ and $89.4{\pm}0.2%$ with the 10% EG treatments with no significant difference between the Isa brown and Commercial breeds. The viability of PGCs after freeze- thawing was significantly higher for Isa brown ($87.4{\pm}0.4%$) and Commercial breeds ($89.4{\pm}0.2%$) than Korean Oge (KO) ($77.6{\pm}1.1%$) and White Leghorn ($76.2{\pm}0.9%$)(p<0.05) using 10% EG cryoprotectant. This study established a method for pre- serving chicken PGCs that enables systematic storage and labeling of cryopreserved PGCs in liquid ($LN_2$) at agermplasm repository and ease of entry into a data base. In the future, the importance for this new technology is that poultry lines can be conserved while work is being conducted on improving the production of germline chimeras.

Evaluation of the testicular toxicity caused by 2-bromopropane in rats (랫드에 있어서 2-bromopropane에 의해 유발된 정소독성의 평가)

  • Kim, Jong-choon;Lee, Hyun-sook;Yun, Hyo-in;Chung, Moon-koo
    • Korean Journal of Veterinary Research
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    • v.40 no.2
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    • pp.361-371
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    • 2000
  • It has been recently reported that 2-bromopropane (2-BP) induces male reproductive toxicity in both human and experimental animals. However, delayed effects of 2-BP on male reproductive system have not been investigated in detail. The present study was conducted to investigate the testicular toxicity of 2-BP and to determine the recovery of normal spermatogenesis in Sprague-Dawley rats. Male rats aged 5 weeks were administered 1,000mg/kg 2-BP by gavage daily for 4 weeks and sacrificed sequentially at 1, 2, 3, 4 and 12 weeks after initiation of 2-BP treatment. Testicular toxicity was evaluated qualitatively by histopathological examinations and quantitatively by reproductive organ weights, spermatid head count, and repopulation index. In the 2-BP treated rats, the body weights was significantly suppressed and the weights of testes and epididymides were also decreased in a time-dependent manner. On histopathological examination, spermatogonia in stages I-VI and preleptotene and leptotene spermatocytes in stages VII-IX were strongly depleted at 1 week of dosing. Spermatogonia were depleted extensively in all spermatogenic stages at 2 weeks. Continuing with the evolution of spermatogenic cycle, zygotene spermatocytes, pachytene spermatocytes, and round spermatids were sequentially depleted at 2, 3, and 4 weeks of dosing due to the depletion of their precursor cells. Vacuolization of Sertoli cells and spermatid retention were also observed at all time points, suggesting that 2-BP induced Sertoli cell dysfunction. At 12 weeks, after 8 weeks recovery, most of the tubules appeared severely atrophic and were lined by Sertoli cells only. Leydig cell hyperplasia in the interstitial tissue was also found. In addition, dramatic reductions in the number of spermatid heads and repopulation index were observed, indicating that 2-BP-induced testicular injury is irreversible. These results indicate that 4 weeks repeated-dose of 1,000mg/kg 2-BP results in a progressive germ cell loss due to the depletion of spermatogonia followed by long-term testicular atrophy in SD rats.

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Study on Analysis of the Proper Ratio and the Effects of Low Impact Development Application to Sewage Treatment District (하수처리구역 내 LID 적용에 대한 적정비율 및 효과분석 연구)

  • Shin, Hyun Suk;Kim, Mi Eun;Kim, Jae Moon;Jang, Jong Kyung
    • Journal of Korea Water Resources Association
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    • v.46 no.12
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    • pp.1193-1207
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    • 2013
  • Increase of impervious area caused by overdevelopment has led to increase of runoff and then the problem of flooding and NPS were brought up. In addition, as decrease of base flow made groundwater level to decline, a stream that dries up is issued. low impact development (LID) method which is possible to mimic hydrological water cycle, minimize the effect of development, and improve water cycle structure is proposed as an alternative. As introduction of LID in domestic increases, the study on small watershed is in process mainly. Also, analysis of property of hydrological runoff and load on midsize watershed, like sewage treatment district, is required, the study on it is still insufficient. So, area applying LID practices from watershed of Dongrae stream is pinpointed and made the ratio and then expand it to watershed of Oncheon stream. Among low impact development practices, Green Roof, Porous Pavement, and Bio- retention are selected for the application considering domestic situations and simulated with SWMM-LID model of each watershed and improvement of water cycle and reduction of non-point pollution loads was analysed. Improvement of water cycle and reduction of non-point pollution loads were analyzed including the property of rainfall and soil over long term simulation. The model was executed according to scenario based on combination of LID as changing conductivity in accordance with soil type of the watershed. Also, this study evaluated area of LID application that meets the efficiency of conventional management as a criteria for area of LID practices applying to sewer treatment district by comparing the efficiency of LID application with that of conventional method.

Caregivers' adherence factors affecting maintenance treatment in children with well-controlled asthma : A qualitative analysis through in-depth interview (천식 조절 상태 환아의 유지 치료에 대한 보호자 순응 요인: 심층 면담을 통한 질적 분석)

  • Choi, Ic Sun;Cho, Saeng Koo;La, Kyong Suk;Byeon, Jung Hye;Song, Dae Jin;Yoo, Young;Choung, Ji Tae
    • Clinical and Experimental Pediatrics
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    • v.53 no.3
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    • pp.364-372
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    • 2010
  • Purpose : Good adherence of caregivers is essential for successful health outcomes in the treatment of childhood asthma. The purpose of this study was to identify the factors contributing to good adherence of maintenance treatment in children with well-controlled asthma. Methods : Children with well-controlled asthma being treated with a daily controller for at least 3 months in Korea University Anam Hospital were selected. Their caregivers who had good adherence to maintenance treatment were recruited. Qualitative study through in-depth interviews was conducted with 18 caregivers who agreed to the study. Results : The 18 caregivers (mean age, 40.0 years) consisted of 15 mothers, 2 grandmothers, and 1 father. The resulting consensus were identified and grouped into 2 domains: the caregiver/patient aspect with 8 theme factors and the treatment aspect with 4 theme factors. The main theme factors in the caregiver/patient aspect were enabling participation in physical activities and exercise (77.8%), perceptions regarding asthma and the need for long-term treatment (50.0%), and perceived value of the medications outweighing the risk of side effects (38.9%). The main theme factors in the treatment aspect were trust in the physician (77.8%), general satisfaction with the manner and attitude of the physician (77.8%) and verification of the necessity of further treatment by performing tests (38.9%). Conclusion : Efforts to improve caregivers' adherence to the treatment of childhood asthma must include a range of factors related to both caregiver/patient aspects and treatment aspects. Among all of these factors, it may be most important to establish a physician-caregiver partnership.

DIRECT PULP CAPPING WITH BONDING RESIN (접착용 레진을 이용한 유치의 직접 치수복조술에 관한 연구)

  • Cho, Hae-Sung;Choi, Yeong-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.33 no.2
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    • pp.165-172
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    • 2006
  • A direct pulp capping with different medicaments has been attempted for a long time. The most commonly used among those is the calcium hydroxide. In primary teeth, however, a success rate of direct pulp capping with calcium hydroxide has been reported to be lower than that of pulpotomy. The disappointing results of calcium hydroxide have prompted the search for other capping materials. Lately, several researchers suggested an application of adhesive resin-based composite systems as a capping material. They claimed that when an exposed vital pulp is capped directly with bonding resin, the pulp tissue is free of inflammation or necrosis without clinical symptoms. The aim of this study was to compare short-term effects of the bonding resin which was applied on the mechanically exposed vital pulp tissue and those of direct pulp capping with calcium hydroxide. The second objective was to compare success rates of the primary teeth which already underwent physiologic root resorption and those of the teeth which had not undergone physiologic root resorption yet, in each capping material groups. The vital, healthy pulp of forty-one primary teeth were exposed mechanically during a cavity preparation. They were divided into two groups: Group 1(n=21) underwent capping with bonding resin, and group 2(n=20) underwent capping with calcium hydroxide. Then these two groups were subdivided into two groups in each : the teeth which show physiologic root resorption and the teeth without root resorption. All of the sample teeth were restored with composite resin. Clinical evaluations such as percussion test, ice test, EPT, were recorded and also before- and after- standard x-ray films were compared and evaluated to decide whether the case was successful or not. Evaluation was performed at least 3 months after the capping materials. The results were as follows 1. There was no difference in success rate between group 1 and group 2. 2. Success rate of the teeth with physiologic root resorption was higher than that of the teeth without physiologic root resorption in group 1 and group 2. 3. There was no difference in success rate between anterior teeth and posterior teeth.

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Characteristics of Physiological Variables(EDR, EMG) in Biofeedback Treatment (바이오피이드백 치료에서 나타나는 신체변수(EDR, EMG)의 특성)

  • Seo, Man-Kil;Han, Woo-Sang;Lee, Kyung-Kyu;Yu, Bum-Hee;Lee, Yu-Ri;Kim, E-Yong;Kim, Hyun-Woo
    • Sleep Medicine and Psychophysiology
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    • v.6 no.1
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    • pp.38-45
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    • 1999
  • Objectives: We explored the characteristics of physiological variables such as electrodermal response(EDR) and electromyography(EMG) in patients with insomnia, panic disorder, and other anxiety disorders. we aimed to decide the minimum sessions in biofeedback treatment to make the treatment effective and examine the effects of long-term biofeedback treatment by measuring the physiological variables. Methods: Thirty seven outpatients who received biofeedback treatment were divided into 3 groups according to the number of biofeedback sessions(patients who received 4-5 sessions, who received 6-9 sessions, and who received more than 10 sessions). We measured mean and delta values of EDR and EMG levels, and the Hamilton Anxiety Rating Scale(HARS), and Slef-Relaxation Inventory(SRI) in all patients. Data were analyzed by t-test and repeated measures analysis of variance. Results: The mean and delta values of EDR and EMG levels were not different among the 3 groups during the first 4 biofeedback sessions. However, patients who received more than 10 biofeedback sessions had higher baseline mean EDR value(F=2.233, p=0.036) in the first session, compared with other patients. In patients who received more than 10 biofeedback sessions, mean EDR was significantly reduced after $5^{th}$ session(F=10.41, p<0.01). They showed significant improvement in SRI scores at 12th biofeedback session(t=2.726, p<0.05) and in HARS scores at $6^{th}$(t=3.10, p<0.05) and $12^{th}$ biofeedback session(t=10.93, p<0.001). Conclusions: Wesuggest that patients should receive more than 5 biofeedback sessions to experience internal cues and get a good clinical response to biofeedback treatment.

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A Feasibility Study on the Use of Liner and Cover Materials Using Sewage Sludge (하수슬러지의 차수재 및 복토재로의 이용타당성에 관한 연구)

  • 유남재;김영길;박병수;정하익
    • Journal of the Korean Geotechnical Society
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    • v.15 no.2
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    • pp.43-71
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    • 1999
  • This research is an experimental work of developing a construction material using municipal wastewater sludge as liner and cover materials for waste disposal landfill. Weathered granite soil and flyash, produced as a by-product in the power plant, were used as the primary additives to improve geotechnical engineering properties of sludge. For secondary additives, bentonite and cement were mixed with sludge to decrease the permeability and to increase the shear strength, respectively. Various laboratory test required to evaluate the design criteria for liner and cover materials, were carried out by changing the mixing ratio of sludge with the additives. Basic soil properties such as specific gravity, grain size distribution, liquid and plastic limits were measured to analyze their effects on permeability, compaction, compressibility and shear strength properties of mixtures. Laboratory compaction tests were conducted to find the maximum dry densities and the optimum moisture contents of mixtures, and their effectiveness of compaction in field was consequently evaluated. Permeability tests of variable heads with compacted samples, and the stress-controlled consolidation tests with measuring permeabilities of samples during consolidation process were performed to obtain permeability, and to find the compressibility as well as consolidational coefficients of mixtures, respectively. To evaluate the long term stability of sludges, creep tests were also conducted in parallel with permeability tests of variable heads. On the other hand, for the compacted sludge decomposed for a month, permeability tests were carried out to investigate the effect of decomposition of organic matters in sludges on its permeability. Direct shear tests were performed to evaluate the shear strength parameters of mixed sludge with weathered granite, flyash and bentonite. For the mixture of sludge with cement, unconfined compression tests were carried out to find their strength with varying mixing ratio and curing time. On the other hand, CBR tests for compacted specimen were also conducted to evaluate the trafficability of mixtures. Various test results with mixtures were assessed to evaluate whether their properties meet the requirements as liner and cover materials in waste disposal landfill.

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Policy Change and Innovation of Textile Industry in Daegu·Kyungbuk Region (대구·경북지역 섬유산업의 정책변화와 혁신과제)

  • Shin, Jin-Kyo;Kim, Yo-Han
    • Management & Information Systems Review
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    • v.31 no.3
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    • pp.223-248
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    • 2012
  • This study analyses support policy and structural change of textile industry in Daegu Kyungbuk region, and suggests major issues for textile industry's innovation. In Daegu Kyungbuk, it was 1999 that a policy, so called Milano Project, in order to promote a textile industry was devised. In 2004, the Regional Industrial Promotion Plan was devised. The plan was born from a view point of establishing a regional innovation system and of promoting the innovative clusters under a knowledge based economy. After then, the Regional Industry Promotion Project or Regional Strategic Industry Promotion Project became a core of regional textile industrial policy. Research results indicated that the first stage Milano project (1999-2003) showed both positive and negative effects. There were no long-term development plan, clear vision and strategy. But, core industrial infrastructure for differentiated product development, such as New product Development Support Center and Dyeing Design Practical Application Center, was constructed. The second stage Daegu Textile Industry Promotion Plan (2004-2008) displayed a significant technological performance and new product sales with the assistance of Kyungbuk province. Also, textile industry revealed positive fruits such as financial structure, productivity, and profitability as a result of strong restructuring. In industrial structure, there was a important change from clothe textile material to industry textile material. Most of textile companies did not showed high capability in CEO's technology innovation intention, entrepreneurship, R&D and human resource competency in compare with other industry. We suggested that Daegu Kyungbuk has to select and concentrate on the high-tech textile material and living textile for sustainable development and competitiveness. We also proposed a confidence and cooperation based innovation network and company oriented innovation cluster.

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

Synthesis Gas Production via Partial Oxidation, CO2 Reforming, and Oxidative CO2 Reforming of CH4 over a Ni/Mg-Al Hydrotalcite-type Catalyst

  • Song, Hoon Sub;Kwon, Soon Jin;Epling, William S.;Croiset, Eric;Nam, Sung Chan;Yi, Kwang Bok
    • Clean Technology
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    • v.20 no.2
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    • pp.189-201
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    • 2014
  • Partial oxidation, $CO_2$ reforming and the oxidative $CO_2$ reforming of $CH_4$ to produce synthesis gas over supported Ni hydrotalcite-type ($Ni_{0.5}Ca_{2.5}Al$ catalyst) catalysts were carried out and the effects of metal supports (i.e.; Mg and Ca) on the formation of a stable double-layer structure on the catalysts were evaluated. The $CH_4$ reforming stability was determined to be affected by the differences in the interaction strength between the active Ni ions and support metal ions. Only a Ni-Mg-Al composition produced a highly stable hydrotalcite-type double-layered structure; while the Ni-Ca-Al-type composition did not. Such structure provides excellent stability for the catalyst (-80% efficiency) as confirmed by the long-term $CO_2$ reforming test (-100 h), while the Ni-Ca-Al catalyst exhibited deactivation phases starting at the beginning of the reaction. The interaction strength between the active metal (Ni) and the supporting components (Mg and Al) was determined by temperature-programed reduction (TPR) analyses. The affinity was also confirmed by the TPR temperature because the Ni-Mg-Al catalyst required a higher temperature to reduce the Ni relative to the Ni-Ca-Al catalyst. The highest initial activity for synthesis gas production was observed for the $Ni_{0.5}Ca_{2.5}Al$ catalyst; however, this activity decreased quickly due to coke formation. The $Ni_{0.5}Ca_{2.5}Al$ catalyst exhibited a high reactivity and was more stable than the other catalysts because it had a higher resistance to coke formation.