• 제목/요약/키워드: Delayed potential

검색결과 293건 처리시간 0.027초

동해안 냉해풍지역의 벼 생육환경 연구 (Study on Rice Growing Environment Against Cold Sea Wind in Eastern Coastal Area of Korean Peninsula)

  • 김정일;이지윤;박동수;박노봉;권오덕;장재기;이지훈;김상열;강항원
    • 한국작물학회지
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    • 제55권2호
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    • pp.133-138
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    • 2010
  • 동해연안지역의 벼 생육부진 및 수량감소의 주된 요인분석을 위하여 해안으로부터 1, 2,3, 5 km의 4개 지점의 기상, 토양 및 벼 생육반응을 조사 분석한 결과는 다음과 같다. 1. 해안거리별 일 평균기온은 차이가 거의 없었으나, 냉수대 출현에 따른 냉해풍 발생시 온도변화는 뚜렷하여 5km에서보다 1 km지점에서 $8^{\circ}C$, 2 km지점 $7^{\circ}C$, 3 km지점 $4^{\circ}C$까지 온도가 낮아졌으며 냉해풍은 하루에도 수차례 발생하였음. 2. 해안거리별 토양특성은 해안에 가까울수록 모래성분이 많고 미사 및 점토성분은 적었으며, 양이온 치환용량이 적어서 작물이 비료성분을 섭취할 수 있는 흡착력이 낮아졌음. 3. 해안에 가까운 재배지역일수록 초장은 작아지고 경수는 적었으며, 출수기는 3~4일 지연되었고, 벼 건물중 및 임실율은 낮아졌음. 4. 수량은 5km보다 1 km지점에서 27~36% 감수되어, 해안에 가까운 재배지역일수록 감수폭이 더 컸으며, 주된 감수요인은 주당수수의 감소가 가장 크게 영향을 미쳤고, 해안 2 km지점에서 90%이상의 수량성을 나타낸 품종은 냉해풍지역의 적응품종인 삼덕벼였음.

목탄을 이용한 친환경 건축자재 이용기술(I) - 목탄으로 제조된 건축자재의 특성 평가 - (Utilization of Charcoal as an Environmentally Friendly Building Materials (I) - Characterization of Building Materials Prepared with Charcoal -)

  • 안병준;조태수;이성숙;백기현;김선익
    • Journal of the Korean Wood Science and Technology
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    • 제37권6호
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    • pp.537-545
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    • 2009
  • 본 연구는 일반 페인트 및 건조시멘트에 목탄을 첨가하여 제조된 건축자재의 제반 물리 화학적 특성 조사를 바탕으로 하여 목탄의 친환경 건축자재 혼합제로서의 활용 가능성을 모색하기 위한 목적으로 수행되었다. 목탄을 포함한 액상몰탈의 물리 화학적 물성 시험결과, 목탄 20% 이상을 포함한 액상몰탈의 경우, 점도에 대한 저항치인 주도와 불휘발분이 품질기준에 적합하였다. 목탄 첨가량이 증가할수록 건조시간은 지연되었으나, 모든 처리구에서 품질기준인 60분 이내에서 건조가 완료되었다. 기타 제반 물성에서는 모든 처리구에서 품질기준을 충족하였다. 이 결과로 볼 때, 액상 몰탈에 대한 적정 목탄 함량은 25%로 판단된다. 건조 시멘트 몰탈에 대한 압축강도는 목탄 5% 첨가구에서 가장 우수하였으며, 20% 이상 첨가구에서는 KS 기준치에 비해 낮은 것으로 조사되었다. 또한 목탄 첨가량 증가로 보수성은 지속적으로 증가하며, 암모니아가스 탈취율의 경우 일반 시멘트 몰탈이 59.5%, 목탄 10% 첨가 시멘트 몰탈은 71.6%의 암모니아를 흡착하였다.

만성신부전 환자에서 혈액투석 전후의 P300 인지유발전위검사 (Event-related Potentials of Pre- and Post-Hemodialysis in Patients with Chronic Renal Failure)

  • 배재천;이상무
    • Annals of Clinical Neurophysiology
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    • 제3권2호
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    • pp.136-142
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    • 2001
  • Background : Nervous system dysfunction is a major complication of end stage renal disease. Although severe neurologic symptoms are partially or completely reversed by adequate hemodialysis, even optimally dialyzed patients will usually not return to normal neurocognitive function. To investigate the influence of chronic renal failure and hemodialysis on higher cognitive function electrophysiologically, we studied auditory P300 event-related potentials in 14 hemodialysis patients and 14 age- and sex-matched normal healthy controls. Methods : The subjects consisted of 14 patients(M: 6, F: 8) with chronic renal failure(CRF) for 1 to 10 years and 14 age- and sex-matched healthy controls(M: 5, F: 9). For the reliability of study, patients with diabetes mellitus, abnormal brain CT findings, or low mini-mental state score(below 20) were excluded. Event related potentials(ERPs) for hemodialysis patients were performed at pre- and post-hemodialysis. To obtain ERPs, subjects underwent 2-tone auditory discrimination test(oddball paradigm). Results : Although the age(control: $48.79{\pm}10.31years$, CRF: $51.21{\pm}7.61years$) and mini-mental state score(control: $27.00{\pm}1.71points$, predialysis CRF: $25.07{\pm}3.58points$) were not different in normal control and CRF groups significantly(P>0.05), P300 latencies at Cz(control: $288.11{\pm}17.36msec$, predialysis CRF: $332.35{\pm}42.34msec$) were significantly delayed(P<0.05)and the duration of Trail making test A was significantly prolonged(control: $64.2{\pm}24.2sec$, CRF: $118.9{\pm}101sec$) in CRF group. P300 latencies between pre- and post-hemodialysis CRF patients(predialysis CRF: $332.35{\pm}42.34msec$, postdialysis CRF: $325.82{\pm}38.69msec$) were not significantly different. The P300 latency was not related with the duration of CRF(Spearman's correlation test, r=0.25, P>0.05) and the frequency of hemodialysis(Spearman's correlation test, r=0.28, P>0.05). Conclusions : From these results, we suggest that P300 latency is valuable in evaluating cognitive brain dysfunction in patients with CRF and hemodialysis does not have a significant effect on cognitive brain dysfunction in patients with CRF.

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Differential Scanning Calorimetry에 의(依)한 고무의 가황발열특성(加黃發熱特性)에 관(關)한 연구(硏究) (Studies on the Characteristics of Rubber Vulcanization Exotherm by Differential Scanning Calorimetry.)

  • 최세영;백남철
    • Elastomers and Composites
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    • 제19권1호
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    • pp.13-31
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    • 1984
  • The purposes of this dissertation are to demonstrate that DSC theromoanaytical methods of vulcanization can provide useful informations on the vulcanization characteristics of industrial formulations and also provides the potential basis for a rapid and complete method of sulfur and vulcanizing accelerator analysis for quality control. The influences of those factors such as heating rate, scan temperature, vucanizing accelerator's type and concentration upon vulcanization exotherm in NR and NBR compounds in the presence of vulcanizing accelerators such as TMTD,MBTS,DPG,TMTM,CBS, and MBT were evaluated by means of DSC. In order to examine the credibility in the DSC method, the same samples which were used for DSC method were studied to compare the DSC results with the ODR (Oscillating Disk Rheometer) data. The results obtained were as follows 1. In the DSC dynamic experiments, the observed enthalpy results from vulcanization depends upon the heating rate; In the range of 2 to $20^{\circ}C/min$ of heating rate, as the heating rate was increased the enthalpy change was also increased. However, over the heating rate of $30^{\circ}C/min$ it was observed that the enthalpy change was decreased as the heating rate was further increased. Without regard to the change of enthalpy, tremendous instantaneous heat evolving was observed in the range of high heating rates. 2. For the samples which are added with various vulcanizing accelerators, the activation energies of vulcanization were as follows; 3. Regarding to the influences of vulcanizining accelerator's types upon the characteristics of vulcanization exotherm, NR and NBR compounds in the presence of thiuramsulphide compounds type accelerators such as TMTD, TMTM, were exhibited sharper and higher vulclanization exotherm than others. From the resuts of DSC thermograms which was distributed in even shape in the broad temperature range, it was clearly shown that the guanidine compounds type accelerator such as DPG acts as a delayed acting accelerator. 4. In the comparison of DSC and ODR results, the dependency of temperature in the cure rate and the observed conversions show good agreements between two results. 5. In the same curatives, by the comparison of glass transition temperatures, it was possible to predict relative values of maximum torques. Consequently, from the present studies, it is shown that the DSC thermoanalytical method can provide an alternate new method for rapid and complete quality control analysis of rubber industry.

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Development of the Korean Developmental Screening Test for Infants and Children (K-DST)

  • Chung, Hee Jung;Yang, Donghwa;Kim, Gun-Ha;Kim, Sung Koo;Kim, Seoung Woo;Kim, Young Key;Kim, Young Ah;Kim, Joon Sik;Kim, Jin Kyung;Kim, Cheongtag;Sung, In-Kyung;Shin, Son Moon;Oh, Kyung Ja;Yoo, Hee-Jeong;Yu, Hee Joon;Lim, Seoung-Joon;Lee, Jeehun;Jeong, Hae-Ik;Choi, Jieun;Kwon, Jeong-Yi;Eun, Baik-Lin
    • Clinical and Experimental Pediatrics
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    • 제63권11호
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    • pp.438-446
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    • 2020
  • Background: Most developmental screening tools in Korea are adopted from foreign tests. To ensure efficient screening of infants and children in Korea, a nationwide screening tool with high reliability and validity is needed. Purpose: This study aimed to independently develop, standardize, and validate the Korean Developmental Screening Test for Infants and Children (K-DST) for screening infants and children for neurodevelopmental disorders in Korea. Methods: The standardization and validation conducted in 2012-2014 of 3,284 subjects (4-71 months of age) resulted in the first edition of the K-DST. The restandardization and revalidation performed in 2015-2016 of 3.06 million attendees of the National Health Screening Program for Infants and Children resulted in the revised K-DST. We analyzed inter-item consistency and test-retest reliability for the reliability analysis. Regarding the validation of K-DST, we examined the construct validity, sensitivity and specificity, receiver operating characteristic curve analysis, and a criterion-related validity analysis. Results: We ultimately selected 8 questions in 6 developmental domains. For most age groups and each domain, internal consistency was 0.73-0.93 and test-retest reliability was 0.77-0.88. The revised K-DST had high discriminatory ability with a sensitivity of 0.833 and specificity of 0.979. The test supported construct validity by distinguishing between normal and neurodevelopmentally delayed groups. The language and cognition domain of the revised K-DST was highly correlated with the K-Bayley Scales of Infant Development-II's Mental Age Quotient (r=0.766, 0.739), while the gross and fine motor domains were highly correlated with Motor Age Quotient (r=0.695, 0.668), respectively. The Verbal Intelligence Quotient of Korean Wechsler Preschool and Primary Scales of Intelligence was highly correlated with the K-DST cognition and language domains (r=0.701, 0.770), as was the performance intelligence quotient with the fine motor domain (r=0.700). Conclusion: The K-DST is reliable and valid, suggesting its good potential as an effective screening tool for infants and children with neurodevelopmental disorders in Korea.

코로나 바이러스 대유행에 따른 치과 의료 관리 가이드라인 (Guidelines for dental clinic infection prevention during COVID-19 pandemic)

  • 김진
    • 대한치과의료관리학회지
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    • 제8권1호
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    • pp.1-7
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    • 2020
  • Dental settings have unique characteristics that warrant specific infection control considerations, including (1) prioritizing the most critical dental services and provide care in a way that minimizes harm to patients due to delayed care, or harm to personnel from potential exposure to persons infected with the COVID-19 disease, and (2) proactively communicate to both personnel and patients the need for them to stay at home if sick. For health care, an interim infection prevention and control recommendation (COVID-19) is recommended for patients suspected of having coronavirus or those whose status has been confirmed. SARS-CoV-2, which is the virus that causes COVID-19, is thought to be spread primarily between people who are in close contact with one another (within 6 feet) through respiratory droplets that are produced when an infected person coughs, sneezes, or talks. Airborne transmission from person-to-person over long distances is unlikely. However, COVID-19 is a new disease, and there remain uncertainties about its mode of spreads and the severity of illness it causes. The virus has been shown to persist in aerosols for several hours, and on some surfaces for days under laboratory conditions. COVID-19 may also be spread by people who are asymptomatic. The practice of dentistry involves the use of rotary dental and surgical instruments, such as handpieces or ultrasonic scalers, and air-water syringes. These instruments create a visible spray that can contain particle droplets of water, saliva, blood, microorganisms, and other debris. While KF 94 masks protect the mucous membranes of the mouth and nose from droplet spatter, they do not provide complete protection against the inhalation of airborne infectious agents. If the patient is afebrile (temperature <100.4°F)* and otherwise without symptoms consistent with COVID-19, then dental care may be provided using appropriate engineering and administrative controls, work practices, and infection control considerations. It is necessary to provide supplies for respiratory hygiene and cough etiquette, including alcohol-based hand rub (ABHR) with 60%~95% alcohol, tissues, and no-touch receptacles for disposal, at healthcare facility entrances, waiting rooms, and patient check-ins. There is also the need to install physical barriers (e.g., glass or plastic windows) in reception areas to limit close contact between triage personnel and potentially infectious patients. Ideally, dental treatment should be provided in individual rooms whenever possible, with a spacing of at least 6 feet between the patient chairs. Further, the use of easy-to-clean floor-to-ceiling barriers will enhance the effectiveness of portable HEPA air filtration systems. Before and after all patient contact, contact with potentially infectious material, and before putting on and after removing personal protective equipment, including gloves, hand hygiene after removal is particularly important to remove any pathogens that may have been transferred to the bare hands during the removal process. ABHR with 60~95% alcohol is to be used, or hands should be washed with soap and water for at least 20 s.

Efficacy of Living Donor Liver Transplantation in Patients with Methylmalonic Acidemia

  • Jang, Jae Guk;Oh, Seak Hee;Kim, Yu Bin;Kim, Seo Hee;Yoo, Han-Wook;Lee, Beom Hee;Namgoong, Jung-Man;Kim, Dae Yeon;Kim, Ki-Hun;Song, Gi-Won;Moon, Deok-Bog;Hwang, Shin;Lee, Sung-Gyu;Kim, Kyung Mo
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • 제24권3호
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    • pp.288-294
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    • 2021
  • Purpose: Despite aggressive medical and nutritional management, patients with methylmalonic acidemia (MMA) often suffer from multi-organ damage. Early deceased donor liver transplantation (DDLT) has emerged as an intervention to prevent disease progression. We investigated the efficacy of living donor LT (LDLT) with a potential carrier of MMA and a small volume of graft in patients with MMA as an alternative to DDLT. Methods: Of five patients (three male, two female; median age 5.7 years; range, 1.3-13.7 years), four underwent carrier LDLT, while one underwent non-carrier auxiliary LDLT. All patients received pre- and post-LT continuous renal replacement therapy and were provided with minimal restriction diet according to serum MMA level after LT. MMA levels in the serum and urine, the incidence of metabolic crisis, and clinical findings before and after LT were compared. Results: The survival rate was 100% during 2.2 years of follow up period after LT. In all five cases, MMA titer in the serum after transplantation decreased with less restrictive diet. Metabolic crisis was not observed during the follow-up period. In addition, no patient showed progression of severe renal impairment requiring hemodialysis. Progression of delayed cognitive development was not observed. Social functioning with improved neuropsychiatric development was observed. Conclusion: This study showed that LDLT achieved improved quality of life with less restrictive diet, therefore it could be a feasible alternative option to DDLT for the treatment of patients with MMA, even with an auxiliary LT.

The Influence of Vacuum Packaging of Hot-Boned Lamb at Early Postmortem Time on Meat Quality during Postmortem Chilled Storage

  • Zhao, Yingxin;Chen, Li;Bruce, Heather L.;Wang, Zhenyu;Roy, Bimol C.;Li, Xin;Zhang, Dequan;Yang, Wei;Hou, Chengli
    • 한국축산식품학회지
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    • 제42권5호
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    • pp.816-832
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    • 2022
  • To evaluate the effects of early postmortem vacuum packaging (VP) on meat quality during postmortem chilled storage, hot-boned lamb was vacuum-packaged at 1, 6, 12, 24, and 48 h postmortem and stored around 2℃ until 168 h postmortem, with lamb packaged in plastic wrap as the control (aerobic packaging). Intramuscular pH decline was delayed when lamb was vacuum packaged at 1, 6, and 12 h postmortem (p<0.05). The lamb vacuum-packaged at 1 h postmortem (VP-1h group) had significantly lower shear force values and purge losses accompanied by lower free thiol group values than other treatments during postmortem storage and was also higher in extractable calpain-1 activity by 6 h postmortem (p<0.05). Free thiol group concentrations were significantly higher after VP at 6 and 12 h postmortem (p<0.05). Packaging lamb under vacuum very early postmortem produced the lowest shear force and purge loss, likely by slowing heat loss and muscle temperature decline, implying that lamb quality is improved by VP when applied very early postmortem. This was at the expense of protein oxidation, which was unrelated to other meat quality measurements, most likely because potential contracture during hot boning confounded its impact. Further research is required to understand the implications of the interaction between protein oxidation, VP, and hot boning on the acceptability of lamb.

구조방정식 모델을 이용한 수소충전소 수용에 미치는 요인분석 (The Factor Analysis for Acceptance on Hydrogen Refueling Station Using Structure Equation Model)

  • 이미정;백종배
    • Korean Chemical Engineering Research
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    • 제60권3호
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    • pp.356-362
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    • 2022
  • 수소 기술과 관련된 연구는 전 세계적으로 활발하게 진행되고 있다. 우리나라도 수소경제 강국으로 도약하기 위해 기술개발에 많은 노력을 기울이고 있다. 특히, 세계 수소차 보급률 1위가 그 증거이다. 그러나 수소차의 인프라인 수소충전소 구축이 지연되고 있다. 지연요인은 대중들의 반대가 가장 크다. 이와 같이, 대중들의 지지를 받지 못한 정책은 성공적으로 실현될 수 없고, 지속가능하지 않다. 따라서 이 연구에서는 수소충전소를 찬성하고 반대하는 수용성에 미치는 요인을 분석하고자 한다. 연구방법으로는 선행연구를 검토하여 수용성에 미치는 기초요인을 파악하였고, 설정된 요인을 바탕으로 설문을 설계하고 조사하였다. 설문에 대한 타당도와 신뢰도를 검증하였으며, 상관분석을 통해 가설을 검증하였다. 그리고, 구조방정식 모델링을 사용하여 수소충전소 수용성에 미치는 요인 모델을 개발하였다. 연구 결과로 수용성을 사적수용성과 공적수용성으로 구분하였으며, 사적수용성의 경우에는 환경에 대한 태도와 수소충전소에 대한 지식의 정도가 높을수록, 수소충전소에 대한 위험을 느끼는 정도가 적을수록 수용성이 크다는 것을 확인하였다. 그리고 공적수용성의 경우에는 이익이 많고, 환경에 대한 태도가 좋을수록, 위험을 감수하는 개인의 특성이 적을수록 수용성이 크다는 것을 확인하였다. 이 연구를 통해 수소충전소 등 국가정책 시행 시 주민들의 수용성 제고 방안을 모색하는 기초자료로써 제공하고, 과학적인 소통의 분석자료로 활용될 것을 기대한다.

Hizikia fusiformis 추출물의 in vitro 및 in vivo에서 혈관신생 감소 연구 (Hizikia Fusiformis Hexane Extract Decreases Angiogenesis in Vitro and in Vivo)

  • 제갈명은;한유선;박시영;이지혁;이의연;김영진
    • 생명과학회지
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    • 제33권9호
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    • pp.703-712
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    • 2023
  • 기존 혈관에서 새로운 혈관을 형성하는 혈관 신생은 혈관 신생 조절인자에 의해 조절되는 다단계 과정이며 배아 발달, 만성 염증 및 상처 복구를 포함한 다양한 생리학적 과정에 필수적이다. 혈관 신생의 조절장애는 암, 자가 면역 질환, 류마티스 관절염, 심혈관 질환 및 상처 치유 지연과 같은 많은 질병을 유발한다. 그러나 효과적인 혈관신생 억제 약물은 제한되어 있으며, 최근 연구에서는 천연 자원에서 잠재적인 약물후보를 식별하는 데 중점을 두고 있다. 예를 들어, 해양 천연물은 항암, 항산화, 항염증, 항바이러스 및 상처 치유 효과를 입증했다. 따라서 본 연구에서는 톳(갈조류) 추출물의 혈관 신생 억제 효과를 확인했습니다. H. fusiformis 추출물은 인간 제대 정맥 내피 세포(HUVECs)에서 세포 이동, 침윤 및 관 형성을 억제하며, 동시에 Matrigel 겔 플러그 분석을 통해 생체 내 혈관 신생을 억제를 확인했다. 또한, 톳 추출물 처리 후 VEGF, Erk, Akt의 활성이 감소하는 것을 확인했다. 이 결과를 토대로 H. fusiformis 추출물이 in vitro 및 in vivo 혈관 신생을 억제함을 시사한다.