• Korean Journal of Microbiology
• /
• v.46 no.3
• /
• pp.233-239
• /
• 2010

Four genes (yqfR, yfmL, ydbR, deaD) were identified as putative DEAD-box RNA helicase genes in the genomic sequence of Bacillus subtilis by homology search. To understand the function of these genes, each of the genes was deleted and the constructed strains were tested for their growth charateristics at different temperatures. The growth rate of ydbR deletion mutant ($T_d$=53 min) was a little bit reduced at $37^{\circ}C$ as compared to that of wild type strain (CU1065). But the growth rate of other three (yqfR, yfmL, deaD) deletion mutants ($T_d$=30-40 min) is nearly equal to the growth rate of wild type ($T_d$=32 min). On the other hands, the growth rate of deletion mutants were reduced at $22^{\circ}C$ in order of yqfR ($T_d$=151 min), yfmL ($T_d$=214 min), ydbR ($T_d$=343 min), which showed cold-sensitive phenotype. The deletion mutant of deaD ($T_d$=109 min) grew equally as compared to the growth rate ($T_d$=102 min) of the wild type at $22^{\circ}C$ and did not show cold-sensitive growth. Double, triple and quadruple deletion mutants of these genes were constructed, and growth rate of these mutants were measured at various temperature conditions ($22^{\circ}C$, $37^{\circ}C$, $42^{\circ}C$) using LB broth. Multiple deletion mutations showed more severe cold-sensitive growth than single deletion mutations, and double deletion of ydbR and yfmL ($T_d$=984 min) showed most cold-sensitive growth than any other double mutants. Such a cold-sensitive growth of these mutations is quite similar to the result of csdA or srmB deletion in E. coli and suggested that physiological role of ydbR and yfmL is related with ribosome assembly.

• Journal of Korean Society of Transportation
• /
• v.19 no.1
• /
• pp.139-148
• /
• 2001

본 연구는 교통사고 야기 자들의 운전정밀적성검사기록과 해당 교통사고기록을 비교하여 특정 운전적성상의 결손이 교통사고와 특정유형의 교통사고에 미치는 영향을 계량적으로 분석하는 것을 목적으로 하였다. 본 연구를 위하여 우리나라에서 가장 빈발하는 인적요인에 의한 교통사고 유형 중에서 교통상충이 빈발하는 지점에서 발생하는 차-대-차 사고를 조사분석대상으로 삼았다. 이와 같이 분석대상사고를 선정한 이유는 교통상충이 교통사고로 발전하는 과정에서 사고 제1당사자의 운전적성의 역할을 파악하고자하는 목적에서이다. 따라서 본 연구의 대상이 되는 교통사고 유형을 1. 교차로 진입부에서의 추돌사고, 2. 교차로내 충추돌사고, 3. 단일로상의 추돌사고로 선정하였다. 판별력이 의문시되는 4개 항목을 제외한 조사분석결과에서 하나의 항목을 제외하고 사고 야기자와 일반인의 운전적성상에 통계적으로 분명한 차이가 있으며 각 항목의 결손자 집단에서의 사고자 비율이 일반운전자 집단에 비해 교통사고를 경험한 확률이 2배 내지 4배 가량 높았다. 또한 특정 유형 사고 야기자와 사고 야기자 전체, 일반운전자 집단간 비교에서도 항목별 결손율이 분명한 다른 형태를 갖고 있다는 사실을 확인했으며, 특정유형의 결손(조합)자 집합에서 특정 교통사고 유형을 야기시켰을 확률이 일반인 집단에 비해 많게는 13배 적게는 3, 4배 정도 높다고 추정되었다.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.28 no.3
• /
• pp.369-373
• /
• 2001

The congenital missing of mandibular second premolars is among the common dental anomaly in children. When a second premolar is diagnosed as congenitally missed, we should consider many factors influencing the treatment plan such as patient's age, states of roots of 2nd primary molar, degree of crowding, skeletal growth pattern, facial profile, procumbency of the incisor and lower facial height, etc. The mineralization of the second premolars begins in the majority of cases at the age of $2\sim2\frac{1}{2}$ years, but this period varies more widely than those for other permanent teeth. Also, mandibular second premolars show the greatest variations in differentiation and calcification. For this reason, aplasia of this group of teeth cannot be diagnosed at early age and with the same degree of certainty. From the clinical studies with 2 cases and some literature review on late development of second premolars, it could be summarized as follows : 1. The 2 cases showed marked delay in the development of mandibular second premolars. 2. After the crypt formation, the speed of calcification seemed nearly normal, suggesting that the delay was due to differentiation rather than calcification. 3. When one is encountered with similar conditions, it would be desirable to consider the possibility of delayed tooth development.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.13 no.1
• /
• pp.30-36
• /
• 1991

Various nerves from many areas of body can be used as a donor of autogenous nerve graft in the microneurosurgical repair of the oral and maxillofacial region. In the grafting procedure of nerve repair, the best results will be achieved with a maximum approximation of fascicular surface at both the porximal and the distal stumps. Therefore, appropriate selection of donor nerve will bring out the best results. The sural nerve has been used as one of the most popular donor nerve in the microneurosurgical repair of the oral and maxillofacial region. The authors examined the fascicular characteristics of the human sural nerve microscopically and compare this results with our previous report of the greater auricular nerve and that of the inferior alveolar nerve.

• Communications of Mathematical Education
• /
• v.12
• /
• pp.103-124
• /
• 2001

수학은 계통성이 강한 학문이다. 이러한 수학의 특성은 학습의 결손이 있거나 학습속도가 느린 학생들에게 수학을 학습하는 데 어려움의 근원이 된다. 특히 중학교 수학에서는 처음으로 형식적인 수학이 도입되기 때문에, 중학교 1학년에서 수학을 제대로 이해하지 못할 경우 그 학생은 수학 장애아, 수학부진아로 전락할 가능성이 있다. 그러나 학교에서의 개별지도는 어려운 실정이다. 따라서 수학 부진아를 선정하여 수학학습에서의 어려움을 진단하고, 학생의 오개념과 오류를 분석한 후, 그 학생에게 맞는 학습전략을 선택하여 처방 지도하고자 한다. 이를 통해 학생의 이해와 사고과정을 알아보고 태도변화를 고찰하는 것을 목적으로 한다.

• Journal of the Society of Naval Architects of Korea
• /
• v.39 no.3
• /
• pp.41-47
• /
• 2002

Turbulent wake behind a ship propeller has been investigated using the adaptive hybrid 2-frame PTV(Particle Tracking Velocimetry). 400 instantaneous velocity fields were measured according to 4 different blade phases and ensemble-averaged to investigate the spatial evolution of the vortical structure of near wake within one propeller diameter downstream. The phase averaged mean velocity fields show the potential wake and the viscous wake formed by the boundary layers developed on the blade surfaces. As the tip vortex evolves downstream, the slipstream is contracted and the turbulent intensity is decreased with viscous dissipation and turbulent diffusion.

• Journal of Veterinary Clinics
• /
• v.27 no.6
• /
• pp.735-739
• /
• 2010

An 8 month old female Maltese (body weight 3.6 kg) was referred with primary complaints of dyspnea and exercise intolerance. Diagnostic imaging studies revealed marked cardiomegaly and prominent main pulmonary trunk dilation on thoracic radiography, abnormally arisen aortic roots (toward right ventricle) with left-to right shunted perimembraneous ventricular septal defect located underneath of aortic root, aortic root was located to predominantly to the right ventricle and pulmonary regurgitation (peak velocity 4.7 m/s, pressure gradient ~88 mmHg) from pulmonary over-circulation and hypertension on echocardiography, indicating double outlet right ventricle (DORV). The dog was treated with furosemide (1 mg/kg, BID) for reducing volume overload at right ventricle, spironolatcone (1 mg/kg) and enalapril (0.5 mg/kg) for minimizing deleterious cardiac remodeling, and sildenafil (1 mg/kg) for lessening pulmonary over-circulation and hypertension. The clinical condition of this dog was improved after 1 week of medical treatment. The dog is currently survived and regularly monitored.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.661-667
• /
• 2001

This paper is concerned with the effects of periodically approaching upstream wakes on cascade-flow and loss. The reduced frequency of the periodic wakes was varied in the narrow range from 0.5 to 0.7. According to a wake-passing through the cascade, two velocity deficits appear near the boundary layer contour in the downstream from about 60% chord-length. The first velocity deficit is caused by a periodic wake and the second one appears after some delayed time. The second velocity deficit may be interpreted as the results of reattachment of flow-separation. The higher reduced frequency decreases the duration time of separation appearance and the lesser loss of aerofoil is resulted.

• 한국정보교육학회:학술대회논문집
• /
• 2008.01a
• /
• pp.236-241
• /
• 2008

수학과 수 연산 영역의 학습 부진 현상은 논리적 위계성이 뚜렷한 수학과의 특성상 이전 학년에서 발생된 학습 결손이나 이해의 부족이 다음 학년에서의 학습 방해나 장애로 이어지며, 이러한 과정의 반복은 학습 부진을 증대시켜 학습 불능에까지 이르게 되는 등 심각한 문제가 되고 있다. 수 연산 능력은 수학 학습의 가장 기초 기능일 뿐 아니라 우리 주변의 생활 속에서 문제 해결력을 키우고 다시 생활 속에 자연스럽게 활용할 수 있는 수학적인 힘을 기르는데 반드시 갖추어야 할 기본 능력이다. 이를 위해 본 연구에서는 수학과 학습부진아의 특성 및 지도에 관한 문헌을 검토 분석하고, 수학과 기초학력을 진단 및 부진 요인을 탐색하여 단계형 수준별 개별화 학습 프로그램을 설계하였으며, 이를 효과적으로 적용할 수 있는 방법을 탐색하였다. 그리고 학업성취도 및 수학 학습 태도에 대한 프로그램의 효과를 검증하였다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.2
• /
• pp.219-226
• /
• 2002

This paper is concerned with the effects of periodically approaching upstream wakes on cascade-flow and loss. The reduced frequency of the periodic wakes was varied in the narrow range from 0.5 to 0.7 Corresponding to a wake-passing through the cascade, two velocity deficits appeared near the boundary layer contour in the downstream from about 60% chord-length. The first velocity deficit was caused by a periodic wake and the second one appeared after some delayed time. The second velocity deficit was interpreted as the results of reattachment of flow-separation. The higher reduced frequency decreased the duration time of separation appearance and the lesser losses of blade were resulted.