Cardiovascular Neurons Mediating Somatosympathetic Reflex in Rostral Ventrolateral Medulla

Goo,Yong-Sook,Kim,Sang-Jeong,Kim,Jun,Sung,Ho-Kyung 대한생리학회 1993 대한생리학회지 Vol.27 No.2

The rostral ventrolateral medulla (RVLM) includes vasopressor neurons, which transmit activation signals to the intermediolateral nucleus (IML) of the spinal cord, where the preganglionic sympathetic nucleus is located, to raise arterial blood pressure (BP). However, controversy exists as to the possible depressor area in the RVLM and the pathway involved. The present study persued evidence far the location of depressor neurons and the pathway by simultaneously observing changes in BP and the firing rate (FR) of cardiovascular neurons (CVNs) in the RVLM during the somatosympathetic reflex (SSR) elicited by peripheral nerve stimulation, since CVNs are known to contribute to the generation of the sympathetic nerve discharge. In 42 cats, anaesthetized with α-chloralose, single unit recording was performed, using carbon filament electrodes inserted into the RVLM, enabling estimation of the post R wave unit histogram (PR-UNlT) and the spike triggered average of sympathetic nerve discharge (STA-SND), allowing identification of CVNs. Antidromic stimulation of spinal T₂ segment was followed to determine whether the identified CVN projects axonal endings to the spinal cord (reticulospinal neuron). The sciatic nerve was electrically stimulated at AΔ-intensity (1 mA, 0.1 ms), 1 Hz and C-intensity (10 mA, 0.5 ms), 20 Hz to elicit the depressor, and pressor responses of the SSR, respectively. Simultaneous measurement of CVN firing rate was made. Experimental results are summarized as follows. 1) 20 out of 98 CVNs had axonal projections to the spinal cord and 17 out of 98 CVNs showed FR changes during SSR. 2) Response patterns of FR and BP during SSR were classified into 8 types. 3) These 8 different response patterns could be further classified into those from pressor and depressor neurons. These results demonstrate that some CVNs were identifiable as reticulospinal neurons responding to anti-dromic stimulation and that CVNs operating as depressor neurons as well as pressor neurons exist in the RVLM, both of which are involved with SSR mediation. Therefore, evidence was found that an independent depressor pathway might be involved in the mediation of SSR.

Passive Sampler에 의한 질소산화물에 대한 오염지도 작성

김창환,정창훈,조정구,최금찬 동아대학교 환경문제연구소 1998 硏究報告 Vol.21 No.1

NO₂ concentrations were investigated by NO₂ filter badge sampler for the urban area. Passive Sampler can be a useful method to evaluate polluted urban area which was not covered total area. In this study, the difference between filter badge sampling data and monitoring network data was about 15% and R value was 0.918294 by statistic analysis which was resulted a favorable correlation. Distribution of NO₂ concentration in Seoul, Pusan, and Kwangju was showed in figures, and NO₂ concentration in Seoul area was the highest among other cities.

직무스트레스와 감기와의 관련성

김동현,박신구,김환철,이의철,김정훈,임종한 大韓産業醫學會 2008 대한직업환경의학회지 Vol.20 No.2

목적: 국내외를 통해 직무스트레스와 감기 등과 같은 감염질환과의 관련성에 대한 연구는 많지 않으며, 특히 국내에서의 연구는 거의 전무한 실정이다. 이에 직무스트레스와 감기와의 관련성을 확인하고자 한다. 방법: 일개 대학병원의 산업의학과에서 보건관리대행을 이행하고 있는 83개의 사업장, 근로자 6,699명에 대해 한국형직무스트레스-단축형(KOSS-SF) 설문지를 배부하였고 회수된 4,637명의 설문지 중 부적절한 응답과 다른 호흡기와 관련한 폐질환을 앓고 있는 237명을 제외한 최종분석 근로자 4,400명(65.7%)의 설문자료를 근거로 연구를 시행하였다. 결과: 감기 경험과의 단변량분석에서 유의한 차이를 보인 요인들과 일상생활 스트레스를 보정한 후 시행한 직무스트레스와 감기 경험과의 로지스틱 희귀분석 결과 직무 자율성 결여를 제외한 직무스트레스 하부 영역 전반(직무요구, 관계갈등, 직무불안정, 조직체계, 보상부적절, 직장문화)에 걸쳐 통계적으로 유의한 차이를 보여주었다. 또한 직무스트레스와 감기 경협 첫수와의 관련성을 확인하기위한 다중회귀분석에서도 비슷한 양상을 보였다. 결론: 직무자율성 결여를 제의한 한국형 직무스트레스 요인 전체가 감기와 관련성을 나타내었다. Objectives: To investigate the relationship between job stress and the common cold which is one of the most common infectious disease. Methods: A KOSS (Korean Occupational Stress Scale)-based questionnaire survey was conducted targeting 6,699 workers, of which 4,637 questionnaires were returned and the data for 237 were excluded due to poor response and having pulmonary disease other than common cold. Consequently, 4,400 (65.7%) returned questionnaires were analyzed. Multiple logistic regression analysis and multiple linear regression, adjusted for daily life stress, confounding variables and both, were used to evaluate the relationship between job stress and the common cold. Results: After adjustment for confounding variables and daily life stress, most of the subscales of job stress contributed to an increased risk of common cold. Conclusions: These results indicated that job stress may play a significant role in increasing the risk of the common cold and that further preventive efforts and studies are needed to reduce job stress and address infectious disease caused by job stress among Korean employees.

중소규모 사업장 근로자의 직무스트레스로 인한 결근, 조퇴 현황과 한국형직무스트레스 하부요인과의 관련성

김정훈,박신구,김동현,김환철,임종한,이의철,이동훈,이지영 大韓産業醫學會 2009 대한직업환경의학회지 Vol.21 No.2

목적: 중소규모 사업장 근로자들의 직무 스트레스로 인한 결근, 조퇴의 현황과 한국형 직무 스트레스 하부 요인과의 관련성을 알아보고자 하였다. 방법: 중소규모 사업장 83곳 근로자들에 대해 한국형 직무스트레스요인 평가도구-단축형(KOSS-SF)과 사회 일반적 특성, 직업적 특정 및 직무스트레스로 인한 결근이나 조퇴 경험여부 등을 묻는 구조화된 자가 기입식 설문을 실시하였고, 응답한 4,350명에 대해 최종 분석을 시행하였다. 직무스트레스로 인한 결근, 조퇴와 한국형 직무스트레스 하부 요인들과의 관련성을 확인하기 위하여 로지스틱 회귀분석을 시행 하였다. 결과: 직무 스트레스로 인한 결근, 조퇴를 한 근로자는 남자에서 7%(196명), 여자에서 8%(113명) 로 조사되었고 한국형 직무 스트레스 하부요인과의 관련성에서는 남, 여 모두 직무요구, 관계갈등, 조직체계, 보상부적절, 직장문화 영역의 스트레스가 높은 군에서 통계적으로 의미있게 직무스트레스로 인한 결근, 조퇴율이 증가하였다. 결론: 중소규모 사업장 근로자들의 직무 스트레스로 인한 결근, 조퇴와 한국형 직무 스트레스 하부요인과의 관련성은 남자에서는 조직체계 영역이 가장 높았고, 여자는 직장문화 영역에서 가장 높은 관련성을 보였다. Objective: The aim of this study was to examine the actual conditions of absence and early leave due to job stress of 4,350 workers in 83 small and medium scale industries, and its relationship to job stress factors using Korean Occupational Stress Scale-Short Form (KOSS-SF). Methods: A structured self-reported questionnaire was used to assess each respondent's Sociodemographics, job stress, experience of absence and early leave due to job stress. Seven KOSS-SF domains of job stress were used. We estimated the relation of absence and early leave due to job stress and job stress factors using logistic regression analyses. Results: Absence or early leave due to job stress occurred in 7% of male workers and 8% of female workers. Multiple regression analysis revealed a significantly positive association job stress-related absence/early leave and job demand, interpersonal conflict, organizational system, lack of rewards and occupational climate. Conclusions: Absence and early leave due to job stress is significantly attributed to organizational System and lack of reward for men, and occupational climate and organizational system for women.

화상 환자에서 발생한 외과적 중재술을 요하는 감염성 심내막염 2예

김근숙,이태유,정연손,최창순,최민호,류제헌,김철홍,조구영,우흥정 대한감염학회 2003 감염과 화학요법 Vol.35 No.3

감염성 심내막염은 화상 후에 발생할 수 있는 치명적인 합병증이다. 임상 증상은 일반적으로 없는 경우가 대부분이고 지속되는 발열과 양성 혈액 배양 검사가 유일하다. 감염의 다른 확실한 원인 없이 발열과 양성 혈액 배양 검사가 있을 때는 감염성 심내막염을 강력하게 의심해야 하며 심장 초음파로 진단 가능하다. 감염성 심내막염은 사망률은 높지만 초기에 진단하면 항생제 정주를 지속하는 것으로 치료할 수 있다. 저자들은 화상환자에서 발생한 수술적 처치를 필요로 하는 감염성 심내막염 2예를 경험하였기에 보고하는 바이다. Infective endocarditis is a rare but fatal complication following burn injury. The clinical presentation is silent, but with persistent fever and positive blood culture. The manipulation of clinical care as well as the burn wound itself and immunosuppression caused by extensive bums puts the burn patients at risk of bacteremia. Staphylococcus aureus and Gram-negative bacilli are most common pathogens of infective endocarditis following burns. We report herein two cases of infective endocarditis in the burn patients who requires surgical intervention. The first case was caused by Pseudomonas aeruginosa with complication of multifocal pneumonia, and the second case by coagulase-negative stapylococcus with cerebral hemorrhage.

염산 메트폴민을 함유하는 경구방출제어형 제제의 제조 및 용출특성

구본철,김정수,이계원,지웅길 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

Metformin is an antihyperglycemic agent of the biguanide class used in the treatment of non-in-sulin-dependent diabetes mellitus. Metformin hydrochloride has intrinsically poor permeability in the lower portion of the GI-tract leading to absorption almost exclusively in the upper part of the GI-tract. Its oral bioavailability is in the range of 50 to 60%. It also has a very high water solubility. In this study, we prepared sustained release matrix system containing metformin hydrochloride using various characteristics of polyethylene oxide (PEO). The metformin hydrochloride matrix tablets were prepared by direct compressed method and wet granulation compressed method with various molecular weight of PEO. Even though the molecular weights of PEOs used were 900K, 2,000K, and 5,000K. Moreover, three types of matrix tablets were formulated compositions were same, the hardness was different. The release kinetics were studied for 9 hours in pH 1.2 simulated gastric fluid and pH 6.8 simulated intestinal fluid, using a dissolution tester at 37.5℃, 50 rpm. As the molecular weight of PEO increased, the release rate decreased due to the slower swelling and dissolution of PEO. For the effect of hardness of matrix tablets, the rate of drug release was decreased with increasing hardness.

잡음 및 오프셋전압 감소를 위한 종형 홀소자의 교류구동

김정헌,류지구,송명희 釜慶大學校 1998 釜慶大學校 論文集 Vol.3 No.2

In this paper, the Alternating Current(AC) driving method of Vertical Hall Device(VHD) which is sensitive to the magnetic field parallel to the surface of the chip is presented. This system consists of the phase inverting circuit and Low Pass Filter(LPF) ect. for the amplification of Hall voltage and reduction of offset voltage and noise. When this system was operated, the offset voltage and noise could be reduced effetively. Also, the output voltage of VHD was ±74.0〔mV〕 in the low magnetic field ranges of ±100〔Gauss〕, the linearity of output voltage were good, and the magnetic field resolucation was 0.74〔mv/Gauss〕.

DC/DC 승압 컨버터의 출력 특성 개선을 위한 스너버 회로 설계

김성종,김인혁,정구종,손영익,한병문 明知大學校 産業技術硏究所 2009 産業技術硏究所論文集 Vol.28 No.-

Applications of DC!DC boost converters are increasing recently in many industrial areas including renewable energy sources. High switching frequency of the power semiconductor devices including MOSFET, IGBT causes the EMI noise owing to the large values of dv/dt and di/dt. Since the EMI noises degrade power efficiency and reliability of the system many researches have been made to reduce the noise. This paper presents a passive snubber circuit to improve the tum-on and turn-off transients of the pulsewidth modulated (PWM) DC/DC boost converters. The noises in the output voltage of the DC!DC converter are reduced by adding a resistor and an inductor to the circuit. Experimental results show the effectiveness of the proposed snubber circuit to improve the output characteristics of the boost converter.

제7차 교육과정에 따른 초등학교 3, 4학년 과학 교과서의 체제와 내용에 대한 인식 조사

김정애,노석구 한국초등과학교육학회 2003 초등과학교육 Vol.22 No.1

The purpose of this study was to develop the quality of the textbook and to find out reasonable selection and structure by examining and analyzing the cognition of teacher and students on the structure and contents of elementary science textbook in the 7th curriculum. The findings of this study were as follows: First, as a result of the students' cognition , their interest level of the learning contents was high and the degree of the difficulty of the learning contents was low on the whole. Second, as a result of the teachers' cognition of contents of the textbook, teachers who taught third graders understood that the third graders have relatively much contents to be studied and the lev디 of the contents of the textbook was high. On the other hand, fourth graders' teachers recognized that contents to be studied and the level of the contents were appropriate. And they understood that there were much work to be studied in the units which were difficult and there were difference between contents to be studied and the degree of the difficulty in some units such as life or the earth field. Third, as a result of the teachers' cognition of structure of the textbook, teachers were very affirmative to reduce school hours. They understood that current numbers and scale of the unit were appropriate. Teachers were satisfied with the structure of elementary science textbook in the 7th curriculum on the whole.

Directed Diffusion을 이용한 등산객 경로추적 시스템 설계 및 성능 분석

김광호,이구연,정충교 江原大學校 産業技術硏究所 2007 産業技術硏究 Vol.27 No.B

In this paper, we propose a design of the implementation for a search and rescue system for mountain climbers and evaluate the performance of the system. Search and rescues of people in emergency situations in mountain areas have been difficult due to lack of information about their location, In the proposed design, several small and commonly-available RF-based sensors, some amount of storage and processing devices are used. Infestations offer geographically intermittent coverage at high speeds. The proposed mountain climber tracking system use the directed diffusion scheme combined with infostation system. We also analyze the performance of the proposed system with NS-2 simulation package. From the performance analysis results, we expect that the proposed system will be very useful to early detect climbers' locations in emergency situations in Korea mountain areas.