• Title/Summary/Keyword: and delay

Search Result 12,818, Processing Time 0.053 seconds

A Study on Air Operator Certification and Safety Oversight Audit Program in light of the Convention on International Civil Aviation (시카고협약체계에서의 항공안전평가제도에 관한 연구)

  • Lee, Koo-Hee;Park, Won-Hwa
    • The Korean Journal of Air & Space Law and Policy
    • /
    • v.28 no.1
    • /
    • pp.115-157
    • /
    • 2013
  • Some contracting States of the Convention on International Civil Aviation (commonly known as the Chicago Convention) issue FAOC(Foreign AOC and/or Operations Specifications) and conduct various safety audits for the foreign operators. These FAOC and safety audits on the foreign operators are being expanded to other parts of the world. While this trend is the strengthening measure of aviation safety resulting in the reduction of aircraft accident, it is the source of concern from the legal as well as economic perspectives. FAOC of the USA doubly burdens the other contracting States to the Chicago Convention because it is the requirement other than that prescribed by the Chicago Convention of which provisions are faithfully observed by almost all the contracting States. The Chicago Convention in its Article 33 stipulates that each contracting State recognize the validity of the certificates of airworthiness and licenses issued by other contracting States as long as they meet the minimum standards of the ICAO. Consequently, it is submitted that the unilateral action of the USA, China, Mongolia, Australia, and the Philippines issuing the FOAC to the aircraft of other States is against the Convention. It is worry some that this breach of international law is likely to be followed by the European Union which is believed to be in preparation for its own unilateral application. The ICAO established by the Chicago Convention to be in charge of safe and orderly development of the international civil aviation has been in hard work to both upgrade and emphasize the safe operation of aircraft. As the result of these endeavors, it prepared a new Annex 19 to the Chicago Convention with the title of "Safety Management" and with the applicable date 14 November 2013. It is this Annex and other ICAO documents relevant to the safety that the contracting States to the Chicago Convention have to observe. Otherwise, it is the economical burden due to probable delay in issuing the FOAC and bureaucracies combined with many different paperworks and regulations depending on where the aircraft is flown. It is exactly to avoid this type of confusion and waste that the Chicago Convention aimed at when it was adopted in 1944. The State of the operator shall establish a system for both the certification and the continued surveillance of the operator in accordance with ICAO SARPs to ensure that the required standards of operations are maintained. Certainly the operator shall meet and maintain the requirements established by the States in which it operate. The authority of a State stops where the authority of another State intervenes or where the former has yielded its power by an international agreement for the sake of international cooperation. Hence, it is not within the realm of the State to issue FAOC towards foreign operators for the reason that these foreign operators are flying in and out of the State. Furthermore, there are other safety audits such as ICAO USOAP, IATA IOSA, FAA IASA, and EU SAFA that assure the safe operation of the aircraft, but within the limit of their power and in compliance with the ICAO SARPs. If the safety level of any operator is not satisfactory, the operator could be banned to operate in the contracting States with watchful eyes until the ICAO SARPs are met. This time-honoured practice has been applied without any serious problems. Besides, we have the new Annex 19 to strengthen and upgrade with easy reference for contracting States. We don't have no reason to introduce additional burden to the States by unilateral actions of some States. These actions have to be corrected. On the other hand, when it comes to the carriage of the Personal or Pilot Log Book, the Korean regulation requiring it is in contrast with other relevant provisions of USA, USOAP, IOSA, and SAFA. The Chicago Convention requires in its Articles 29 and 34 only the carriage of the Journey Log Book and some other certificates, but do not mention the Personal Log Book at all. Paragraph 5.1.1.1 of Annex 1 to the Chicago Convention even makes it clear that the carriage in the aircraft of the Personal Log Book is not required on international flights. The unique Korean regulation in this regards giving the unnecessary burden to the national flag air carriers has to be lifted at once.

  • PDF

Clinical Study on Thoracic Actinomycosis (흉부 방선균종의 임상적 고찰)

  • Hong, Sang-Bum;Kim, Woo-Sung;Lee, Jae-Hwan;Bang, Sung-Jo;Shim, Tae-Son;Lim, Chae-Man;Lee, Sang-Do;Koh, Youn-Suck;Lee, In-Chul;Kim, Dong-Soon;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
    • /
    • v.45 no.5
    • /
    • pp.1058-1066
    • /
    • 1998
  • Background: Actinomycotic infection is uncommon and primary actinomycosis of the lung and chest wall has been less frequently reported. This disease may present as chronic debilitating illness with radiologic manifestation simulating lung tumor, pulmonary infiltrating lesion, or chronic suppuration. Diagnosis of choice was not definded yet and role of bronchoscopy on diagnosis was not described yet. Methods: From 1989 to 1998, we experienced 17 cases of thoracic actinomycosis. We have reviewed the case notes of 17 patients with thoracic actinomycosis. The mean age at presentation was $53{\pm}13$ years, 11 were male. Results: Cough, hemoptysis, sputum production, chest pain and weight loss were the commonest symptoms. The mean delay between presentation and diagnosis was $6.6{\pm}7.8$ months. There were six patients who presented with a clinical picture of a suppurative lesion and eleven patients were suspected of having primary lung tumor initially. In no cases was made an accurate diagnosis at the time of hospital admission. Associated diseases were emphysema (1 case), bronchiectasis (2 cases) and tuberculosis (2 cases). Bronchoscopic findings were mucosal swelling and stenosis(n=4), mucosal swelling, stenosis and necrotic covering (n=2), mass (n=3), mass and necrotic covering (n=1) and normal(n=6). Radiologic findings were mass lesion(n=8), pneumonitis(n=3), atelectasis(n=3), pleural effusion(n=2), and normal(n=3). Final diagnosis was based on percutaneous needle aspiration and biopsy (n=3), bronchoscopic biopsy specimens (n=9), mediastinoscopic biopsy (n=1) and histologic examination of resected tissue in the remaining patients(n=4) who received surgical excision. Among 17 patients, 13 were treated medically and the other 4 received surgical intervention followed by antibiotic treatment. Regarding the surgically treated patients, suspected malignancy is the most common indication for operation. However. both medically and surgically treated patients achieved good clinical results. Conclusion: Thoracic actinomycosis is rare. but should still be considered in the differential diagnosis of a chrinic, localized pulmonary lesion. Thoracic actinomycosis may co-exist with pulmonary tuberculosis or lung cancer. If the lesion is located in the central of the lung. the bronchoscopy is recommanded for the diagnosis.

  • PDF

Study on the Short-Term Hemodynamic Effects of Experimental Cardiomyoplasty in Heart Failure Model (심부전 모델에서 실험적 심근성형술의 단기 혈역학적 효과에 관한 연구)

  • Jeong, Yoon-Seop;Youm, Wook;Lee, Chang-Ha;Kim, Wook-Seong;Lee, Young-Tak;Kim, Won-Gon
    • Journal of Chest Surgery
    • /
    • v.32 no.3
    • /
    • pp.224-236
    • /
    • 1999
  • Background: To evaluate the short-term effect of dynamic cardiomyoplasty on circulatory function and detect the related factors that can affect it, experimental cardiomyoplasties were performed under the state of normal cardiac function and heart failure. Material and Method: A total of 10 mongrel dogs weighing 20 to 30kg were divided arbitrarily into two groups. Five dogs of group A underwent cardiomyoplasty with latissimus dorsi(LD) muscle mobilization followed by a 2-week vascular delay and 6-week muscle training. Then, hemodynamic studies were conducted. In group B, doxorubicin was given to 5 dogs in an IV dose of 1 mg/kg once a week for 8 weeks to induce chronic heart failure, and simultaneous muscle training was given for preconditioning during this period. Then, cardiomyoplasties were performed and hemodynamic studies were conducted immediately after these cardiomyoplasties in group B. Result: In group A, under the state of normal cardiac function, only mean right atrial pressure significantly increased with the pacer-on(p<0.05) and the left ventricular hemodynamic parameters did not change significantly. However, with pacer-on in group B, cardiac output(CO), rate of left ventricular pressure development(dp/dt), stroke volume(SV), and left ventricular stroke work(SW) increased by 16.7${\pm}$7.2%, 9.3${\pm}$3.2%, 16.8${\pm}$8.6%, and 23.1${\pm}$9.7%, respectively, whereas left ventricular end-diastole pressure(LVEDP) and mean pulmonary capillary wedge pressure(mPCWP) decreased by 32.1${\pm}$4.6% and 17.7${\pm}$9.1%, respectively(p<0.05). In group A, imipramine was infused at the rate of 7.5mg/kg/hour for 34${\pm}$2.6 minutes to induce acute heart failure, which resulted in the reduction of cardiac output by 17.5${\pm}$2.7%, systolic left ventricular pressure by 15.8${\pm}$2.5% and the elevation of left ventricular end-diastole pressure by 54.3${\pm}$15.2%(p<0.05). With pacer-on under this state of acute heart failu e, CO, dp/dt, SV, and SW increased by 4.5${\pm}$1.8% and 3.1${\pm}$1.1%, 5.7${\pm}$3.6%, and 6.9${\pm}$4.4%, respectively, whereas LVEDP decreased by 11.7${\pm}$4.7%(p<0.05). Comparing CO, dp/dt, SV, SW and LVEDP that changed significantly with pacer-on, both under the state of acute and chronic heart failure, augmentation widths of these left ventricular hemodynamic parameters were significantly larger under the state of chronic heart failure(group B) than acute heart failure(group A)(p<0.05). On gross inspection, variable degrees of adhesion and inflammation were present in all 5 dogs of group A, including 2 dogs that showed no muscle contraction. No adhesion and inflammation were, however, present in all 5 dogs of group B, which showed vivid muscle contractions. Considering these differences in gross findings along with the following premise that the acute heart failure state was not statistically different from the chronic one in terms of left ventricular parameters(p>0.05), the larger augmentation effect seen in group B is presumed to be mainly attributed to the viability and contractility of the LD muscle. Conclusion: These results indicate that the positive circulatory augmentation effect of cardiomyoplasty is apparent only under the state of heart failure and the preservation of muscle contractility is important to maximize this effect.

  • PDF

Considerable Aspects for Technical and Vocational Training in Forestry (임업기술(林業技術) 및 직업훈련(職業訓練)에 고려(考慮)되어야 할 사항(事項))

  • Ma, Sang Kyu
    • Journal of Korean Society of Forest Science
    • /
    • v.51 no.1
    • /
    • pp.56-65
    • /
    • 1981
  • The training of forest ranger level and forest worker level to push the sound forest management and to increase the employment effects in forestry will be done without delay as soon as possible. So several opinions to be considered are here discussed. 1. The ranger level will be at first completely trained with the technics developed and modernized, to process really the sound forest management based on the concept of ecological and economical technic. 2. The organization of vocational training and it's systematical training method will be newly adopted to increase the labour efficiency in forestry. The case of fulltime worker level should be more intensively trained and part-time worker or forest famer level should be trained by the forest ranger and skilled worker with visiting circularly their working place. And the daily employed workers and village people for working should be done by the skilled workers. 3. The training subjects for them at the beginning step will be exploited by the instructors and concerned experts with studying their current conditions. Their practical training is more reasonable to do in the practically managing forest and to carry out under the responsible of leader of this forest. 4. The instructors included rangers of training forest will get specially certain intensive training through the aids of outside experts or through the group instruction with them. 5. The training fields and their reasons to be learned by them are discussed in this paper from the basic knowledge to the skill technics. 6. In oder to systematize and mordernize more rapidly our forest technics that need for training them and also applying directly in the forest management, a total effort of certain type by scientists and technicians scattered individually all over the country is now earnestly demanded to synthesize their knowledge, technic and experience. So to do like this, the establishment of certain organization through which can do their total efforts together will be considered and assisted by the concerned authority. 7. For better lieving of full-time workers, the whole-round year working amount have to be supplied though the work technic-and working plan development. And under the conditions that the timber harvesting work is still not so enough and it has a bad climatic season, the in-side working system and side - job aids will be developed for their sound lieving. 8. The organization of labour management will be soon introduced in the concerning administrativ authority to solve the forest labour problems and to increase the employing effects in forestry in future. 9. The supply programm of improved and trained tools and maschines for forest work is also considered to use by the trained persons. If not to do so, the training results will return to the original condition and will get nothing any more.

  • PDF

Methylenetetrahydrofolate Reductase C677T Polymorphism in Gastric Cancer (위암에서 Methylenetetrahydrofolate Reductase C677T의 유전자 다형성)

  • Seo Won;Park Won Cheol;Lee Jeong Kyun;Kim Jeong Jung
    • Journal of Gastric Cancer
    • /
    • v.5 no.1
    • /
    • pp.10-15
    • /
    • 2005
  • Purpose: Recently the role of vitamins, folate in particular, has been emphasized in the maintenance of health. Folate deficiency is known to give rise to developmental delay, immature vascular disease, neural tube defect, acute leukemia, atherosclerotic vascular disease, delivery defects, breast cancer, and particularly gastrointestinal neoplasia. Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in folate metaboism, and influences DNA synthesis and DNA methylation. Generally, folate deficiency is associated with gastrointestinal neoplasms. The amino-acid- changing and enzyme-activity-reducing nucleotide polymorphism (766C$\rightarrow$T/ Ala222Val) has been described in the MTHFR polymorphism and leads to low enzyme activity that may reduce the capacity of DNA methylation and possibly uracil mis-incorporation into DNA. These processes may be critical in the oncogenic transformation of human cells, especially in colorectal carcinomas. We investigated the relationship between the MTHFR polymorphism in gastric cancer and the tumor site, the smoking history, and the alcoholic history. Materials and Methods: Ninety-six (96) individuals with gastric cancer and 287 healthy persons were analyzed. Blood sampling was performed, PCR-RFLP was analyzed, and MTHFR polymorphism genotypes of C/C, C/T, and T/T were obtained and analyzed statistically for their correlation. Results: In the gastric cancer group there were 69 ($72\%$) males and 27 ($28\%$) females. There were also 58 cases ($60\%$) involving the gastric lower body, 20 cases ($21\%$) the gastric mid-body, and 18 cases ($19\%$) the gastric upper body. In the control group there were 169 ($59\%$) males and 118 ($41\%$) females. Among the gastric cancer, 56 ($61\%$) smoking patients, 40 ($39\%$) non-smoking patients, 45($47\%$) alcoholic patients, 51 ($53\%$) non-alcoholic patients. In the gastric cancer group, MTHER polymorphisms were C/C in 18 ($19\%$) cases, C/T in 59 ($61\%$) cases, T/T in 19 ($20\%$) cases. In the control group polymorphisms were C/C 116 ($40\%$) cases, C/T 103 ($36\%$) cases, and T/T 68 ($24\%$) cases (P=0.045). In cases of lower gastric body cancer, polymorphisms were C/C in 16 ($24\%$) C/C in 16 ($24\%$) cases and C/T or T/T in 42 ($72\%$) cases. In cases of upper and mid-body cancer, polymorphisms were C/C in 2 ($5\%$) cases and C/T or T/T 36 ($95\%$) cases (P=0.006). In the non-smoking patient group, polymorphisms were C/C in 5 (12%) cases and C/T or T/T in 35 ($88\%$) cases. In the smoking patient group, C/C in 13 ($23\%$) cases and C/T or T/T in 43 ($77\%$) cases (P=0.189). In the non-alcoholic patient group, polymorphisms were C/C in 6 ($12\%$) cases and C/T or T/T in 45 ($88\%$) cases. In the alcoholic patient group, polymorphisms were C/C in 12 ($26\%$) cases and C/T or T/T in 33 ($74\%$) cases (P=0.063) Conclusion: MTHFR polymorphisms are associated with gastric cancer and tumor site, but not with smoking and alcohol drinking.

  • PDF

Effects of Planting and Harvest Times on the Forage Yield and Quality of Spring and Summer Oats in Mountainous Areas of Southern Korea (남부산간지에서 봄과 여름 조사료 귀리의 파종과 수확 시기에 따른 조사료 품질과 생산성 변화)

  • Shin, Seonghyu;Lee, Hyunjung;Ku, Jahwan;Park, Myungryeong;Rha, Kyungyoon;Kim, Byeongju
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.66 no.2
    • /
    • pp.155-170
    • /
    • 2021
  • Oats (Avena sativa L.) represent a good forage crop for cultivation in regions with short growing periods and/or cool weather, such as the mountainous areas of southern Korea. In this study, using the Korean elite summer oat varieties 'High speed' and 'Dark horse', we aimed to determine the optimal time to plant and harvest forage oats seeded in spring and summer in a mountainous area. Seeds were planted three times from late February and early August at 9- or 10-days intervals, respectively, and plants were harvested three times from late May to October at 10-day intervals. The experiment was carried out in an upland field (Jangsu-gun Jeonbuk) in 2015 and 2016. We investigated the changes in forage yield (FY) and quality [crude protein (CP) and total digestible nutrient (TDN) contents] based on the time of planting and harvest. Neither the forage quality nor yield of either spring and summer oats was significantly influenced by the time of planting. The CP of spring oats harvested three times at 10-day intervals from late May was 12.0%, 8.2%, and 6.5%, thereby indicating a reduction with a delay in the time of harvest. In summer oats, CP ranged from 8.4% to 8.7%, although unlike CP in spring oats, was not significantly influenced by the time of harvest. For both forage types, harvest time had no significant effect on TDN. The FY of spring oats harvested in late May and early and mid-June was 10.2, 18.7, and 19.5 ton ha-1, respectively, with that of oats harvested on the latter two dates being significantly increased by 83% and 91%, respectively, compared with that in late May. Similarly, the FY of spring oats harvested in late October and early and mid-November was 7.1, 12.5, and 12.1 ton ha-1, respectively, with that of oats harvested on the latter two dates being significantly increased by 75% and 71%, respectively, compared with that in late October. Taking into consideration forage yield and quality (not less than 8% CP), it would be profitable to plant spring oats in the mountainous areas of southern Korea until March 15 and harvest around June 10, whereas summer oats could be beneficially planted until August 25 and harvested from early November.

Effect of Cooling Timing in the Root Zone on Substrate Temperature and Physiological Response of Sweet Pepper in Summer Cultivation (여름 파프리카 수경재배에서 근권 냉방 시간이 근권 온도와 생리적 반응에 미치는 영향)

  • Choi, Ki Young;Ko, Ji Yeon;Yoo, Hyung Joo;Choi, Eun Young;Rhee, Han Cheol;Lee, Yong-Beom
    • Horticultural Science & Technology
    • /
    • v.32 no.1
    • /
    • pp.53-59
    • /
    • 2014
  • This study aimed to determine an appropriate cooling timing in the root zone for lowering substrate temperature and its effect on physiological response of sweet pepper (Capsicum annum L. 'Orange glory') grown on coir substrate in summer, from the July 16 to October 15, 2012. Daily temperature of substrate, root activity, leaf water potential, first flowering date, and the number of fruits were measured by circulating cool water through a XL pipe in the root zone during either all day (all-day) or only night time (5 p.m. to 3 a.m.; night) from the July 23 to September 23, 2012. For comparison, no cooling (control) was also applied. Between the $23^{rd}$ of July and $31^{st}$ of August (hot temperature period), daily average temperatures in substrates were $25.6^{\circ}C$, $26.1^{\circ}C$, and $29.1^{\circ}C$ for the all-day and night treatment, and control respectively. About 1.8 to $5^{\circ}C$ lower substrate temperature was observed in both treatments compared to that of control. In sunny day ($600-700 W{\cdot}m^{-2}{\cdot}s^{-1}$), the highest temperature of substrate was measured between 4 p.m. and 5 p.m. under both the all-day and night treatments, whereas it was measured between 7 p.m. and 8 p.m. under the control. Substrate temperatures during the day (6 a.m. to 8 p.m.) and night (8 p.m. to 6 a.m.) differed depending on the treatments. During the day and night, averaged substrate temperature was lower about $3.3^{\circ}C$ and $4.0^{\circ}C$ for the all-day, and $2.1^{\circ}C$ and $3.4^{\circ}C$ for the night treatment, compared to that of control. In the all-day and night treatment, the TD [TD = temperature of (control)] was greater in bottom than that of other regions of the substrate. Between the day and night, no different TD values were observed under the all-day treatment, whereas under the night treatment there was difference with the greatest degree in the bottom of the substrate. During the hot temperature period, total numbers of days when substrate temperature was over $25^{\circ}C$ were 40, 23 and 27 days for the control, all-day, and night treatment, respectively, and the effect of lowering substrate temperature was therefore 42.5% and 32.5% for the all-day and night treatment, respectively, compared to that for the control. Root activity and leaf water potential of plants grown under the all-day treatment were significantly higher than those under the night treatment. The first flowering date in the all-day treatment was similar to that in the night treatment, but 4-5 day faster than in the control. Also, the number of fruits in both treatments was significantly higher than that in the control. However, there was no effect of root zone cooling on eliminating delay in fruiting caused by excessively higher air temperature (> $30^{\circ}C$), although the substrate temperature was reduced $18^{\circ}C$ to $5^{\circ}C$. These results suggest that the method of cooling root zone temperature need to be incorporated into the lowering growing temperature for growth and fruit set of health paprika.

Meteorological Constraints and Countermeasures in Rice Breeding -Breeding for cold tolerance- (기상재해와 수도육종상의 대책 - 내냉성품종육성방안-)

  • Mun-Hue Heu;Young-Soo Han
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.27 no.4
    • /
    • pp.371-384
    • /
    • 1982
  • Highly cold tolerant varieties are requested not only at high latitute cool area but also tropical high elevated areas, and the required tolerance is different from location to location. IRRI identified 6 different types of cold tolerance required in the world for breeding purpose; a) Hokkaido type, b) Suweon type, c) Taipei 1st season type, d) Taipei 2nd season type, e) Tropical alpine type and, f) Bangladesh type. The cold tolerance requested in Korea is more eargent in Tongil group cultivars and their required tolerance is the one such as the physiological activities at low temperature are as active as in Japonica group cultivars at least during young seedling stage and reproduction stage. With conventional Japonica cultivars, such cold tolerant characters are requested as short growth duration but stable basic vegetative growth, less sensitive to high temperature and less prolonged growth duration at low temperature. The methods screening for cold tolerance were developed rapidly after the Tongil cultivar was reliesed. The facilities of screening for cold tolerance, such as, low temperature incubator, cold water tank, growth cabinet, phytotron, cold water nursery in Chuncheon, breeding nursery located in Jinbu, Unbong and Youngduk, are well established. Foreign facilities such as, cold water tank with the rapid generation advancement facilities, cold nurseries located in Banaue, Kathmandu and Kashimir may be available for the screening of some limitted breeding materials. For the reference, screening methods applied at different growth stages in Japan are introduced. The component characters of cold tolerance are not well identified, but the varietal differences in a) germinability, b) young seedling growth, c) rooting, d) tillering, e) discolation, f) nutrition uptake, g) photosynthesis rate, h) delay in heading, i) pollen sterility, and j) grain fertility at low temperature are reported to be distinguishable. Relationships among those traits are not consistent. Reported studies on the inheritance of cold tolerance are summarized. Four or more genes are controlling low temperature germinability, one or several genes are controlling seedling tolerance, and four or more genes are responsible for the pollen fertility of the rice treated with cold air or grown in the cold water nursery. But most of those data indicate that the results may come out in different way if those were tested at different temperature. Many cold tolerant parents among Japonicas, Indicas and Javanicas were identified as the results of the improvement of cold tolerance screening techniques and IRTP efforts and they are ready to be utilized. Considering a) diversification of germ plasm, b) integration of resistances to diseases and insects, c) identification of adaptability of recommending cultivars and, d) systematic control of recommending cultivars, breeding strategies for short term and long term are suggested. For short term, efforts will be concentrated mainly to the conventional cultivar group. Domestic cultivars will be used as foundation stock and ecologically different foreign introductions such as from Hokkaido, China or from Taiwan, will be used as cross parents for the adjustment of growth durations and synthsize the prototype of tolerances. While at the other side, extreme early waxy Japonicas will be crossed with the Indica parents which are identified for their resistances to the diseases and insects. Through the back corsses to waxy Japonicas, those Indica resistances will be transfered to the Japonicas and these will be utilized to the crosses for the improvement of resistances of prototype. For the long term, efforts will be payed to synthsize all the available tolerances identified any from Japonicas, Indicas and Javanicas to diversify the germ plasm. The tolerant cultivars newly synthsized, should be stable and affected minimum. to the low temperature at all the growing stages. The resistances to the diseases and insects should be integrated also. The rapid generation advancement, pollen culture and international cooperations were emphasized to maximize the breeding efficiency.

  • PDF

THE EFFECTS OF THERMAL STIMULI TO THE FILLED TOOTH STRUCTURE (온도자극이 충전된 치질에 미치는 영향)

  • Baik, Byeong-Ju;Roh, Yong-Kwan;Lee, Young-Su;Yang, Jeong-Suk;Kim, Jae-Gon
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.26 no.2
    • /
    • pp.339-349
    • /
    • 1999
  • The dental structure substituted by restorative materials may produce discomfort resulting from hot or cold stimuli. To investigate the effects of this stimuli on the human teeth, thermal analysis was carried out by calculation of general heat conduction equation in a modeled tooth using numerical method. The method has been applied to axisymmetric and two-dimensional model, analyzing the effects of constant temperature $4^{\circ}C\;and\;60^{\circ}C$. That thermal shock was provided for 2 seconds and 4 seconds, respectively and recovered to normal condition of $20^{\circ}C$ until 10 seconds. The thermal behavior of tooth covered with a crown of gold or stainless steel was compared with that of tooth without crown. At the same time, the effects of restorative materials(amalgam, gold and zinc oxide-eugenol(ZOE)) on the temperature of PDJ(pulpo-dentinal junction) has been studied. The geometry used for thermal analysis so far has been limited to two-dimensional as well as axisymmetric tooth models. But the general restorative tooth forms a cross shaped cavity which is no longer two-dimensional and axisymmetric. Therefore, in this study, the three-dimensional model was developed to investigate the effect of shape and size of cavity. This three-dimensional model might be used for further research to investigate the effects of restorative materials and cavity design on the thermal behavior of the real shaped tooth. The results were as follows; 1. When cold temperature of $4^{\circ}C$ was applied to the surface of the restored teeth with amalgam for 2 seconds and recovered to ambient temperature of $20^{\circ}C$, the PDJ temperature decreased rapidly to $29^{\circ}C$ until 3 seconds and reached to $25^{\circ}C$ after 9 seconds. This temperature decreased rather slowly with stainless steel crown, but kept similar temperature within $1^{\circ}C$ differences. Using the gold as a restorative material, the PDJ temperature decreased very fast due to the high thermal conductivity and reached near to $25^{\circ}C$ but the temperature after 9 seconds was similar to that in the teeth without crown. The effects of coldness could be attenuated with the ZOE situated under the cavity. The low thermal conductivity caused a delay in temperature decrease and keeps $4^{\circ}C$ higher than the temperature of other conditions after 9 seconds. 2. The elapse time of cold stimuli was increased also until 4 seconds and recovered to $20^{\circ}C$ after 4 seconds to 9 seconds. The temperature after 9 seconds was about $2-3^{\circ}C$ lower than the temperature of 2 seconds stimuli, but in case of gold restoration, the high thermal conductivity of gold caused the minimum temperature of $21^{\circ}C$ after 5 seconds and got warm to $23^{\circ}C$ after 9 seconds. 3. The effects of hot stimuli was also investigated with the temperature of $60^{\circ}C$. For 2 seconds stimuli, the temperature increased to $40^{\circ}C$ from the initial temperature of $35^{\circ}C$ after 3 seconds of stimuli and decreased to $30^{\circ}C$ after 9 seconds in the teeth without crown. This temperature was sensitive to surface temperature in the teeth with gold restoration. It increased rapidly to $41^{\circ}C$ from the initial temperature of $35^{\circ}C$ after 2 seconds and decreased to $28^{\circ}C$ after 9 seconds, which showed $13^{\circ}C$ temperature variations for 9 seconds upon the surface temperature. This temperature variations were only in the range of $5^{\circ}C$ by using ZOE in the bottom of cavity and showed maximum temperature of $37^{\circ}C$ after 3 seconds of stimuli.

  • PDF

Clinical Results and Optimal Timing of OPCAB in Patients with Acute Myocardial Infarction (급성 심근경색증 환자에서 시행한 OPCAB의 수술시기와 검색의 정도에 따른 임상성적)

  • Youn Young-Nam;Yang Hong-Suk;Shim Yeon-Hee;Yoo Kyung-Jong
    • Journal of Chest Surgery
    • /
    • v.39 no.7 s.264
    • /
    • pp.534-543
    • /
    • 2006
  • Background: There are a lot of debates regarding the optimal timing of operation of acute myocardial infarction (AMI). Off pump coronary artery bypass grafting (OPCAB) has benefits by avoiding the adverse effects of the cardio-pulmonary bypass, but its efficacy in AMI has not been confirmed yet. The purpose of this study is to evaluate retrospectively early and mid-term results of OPCAB in patients with AMI according to transmurality and timing of operation. Material and Method: Data were collected in 126 AMI patients who underwent OPCAB between January 2002 and July 2005, Mean age of patients were 61.2 years. Male was 92 (73.0%) and female was 34 (27.2%). 106 patients (85.7%) had 3 vessel coronary artery disease or left main disease. Urgent or emergent operations were performed in 25 patients (19.8%). 72 patients (57.1%) had non-transmural myocardial infarction (group 1) and 52 patients (42.9%) had transmural myocardial infarction (group 2). The incidence of cardiogenic shock and insertion of intra-aortic balloon pump (IABP) was higher in group 2. The time between occurrence of AMI and operation was divided in 4 subgroups (<1 day, $1{\sim}3\;days,\;4{\sim}7\;days$, >8 days). OPCAB was performed a mean of $5.3{\pm}7.1$ days after AMI in total, which was $4.2{\pm}5.9$ days in group 1, and $6,6{\pm}8.3$ days in group 2. Result: Mean distal an-astomoses were 3.21 and postoperative IABP was inserted in 3 patients. There was 1 perioperative death in group 1 due to low cardiac output syndrome, but no perioperative new MI occurred in this study. There was no difference in postoperative major complication between two groups and according to the timing of operation. Mean follow-up time was 21.3 months ($4{\sim}42$ months). The 42 months actuarial survival rate was $94.9{\pm}2.4%$, which was $91.4{\pm}4.7%$ in group 1 and $98.0{\pm}2.0%$ in group 2 (p=0.26). The 42 months freedom rate from cardiac death was $97.6{\pm}1.4%$ which was $97.0{\pm}2.0%$ in group 1 and $98.0{\pm}2.0%$ in group 2 (p=0.74). The 42 months freedom rate from cardiac event was $95.4{\pm}2.0%$ which was $94.8{\pm}2.9%$ in group 1 and $95.9{\pm}2.9%$ in group 2 (p=0.89). Conclusion: OPCAB in AMI not only reduces morbidity but also favors hospital outcomes irrespective of timing of operation. The transmurality of myocardial infarction did not affect the surgical and midterm outcomes of OPCAB. Therefore, there may be no need to delay the surgical off-pump revascularization of the patients with AMI if surgical revascularization is indicated.