• Title/Summary/Keyword: internal control method

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Real-time Body Surface Motion Tracking using the Couch Based Computer-controlled Motion Phantom (CBMP) and Ultrasonic Sensor: A Feasibility Study (CBMP (Couch Based Computer-Controlled Motion Phantom)와 초음파센서에 기반한 실시간 체표면 추적 시스템 개발: 타당성 연구)

  • Lee, Suk;Yang, Dae-Sik;Park, Young-Je;Shin, Dong-Ho;Huh, Hyun-Do;Lee, Sang-Hoon;Cho, Sam-Ju;Lim, Sang-Wook;Jang, Ji-Sun;Cho, Kwang-Hwan;Shin, Hun-Joo;Kim, Chul-Yong
    • Progress in Medical Physics
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    • v.18 no.1
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    • pp.27-34
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    • 2007
  • Respiration sating radiotherapy technique developed In consideration of the movement of body surface and Internal organs during respiration, is categorized into the method of analyzing the respiratory volume for data processing and that of keeping track of fiducial landmark or dermatologic markers based on radiography. However, since these methods require high-priced equipments for treatment and are used for the specific radiotherapy. Therefore, we should develop new essential method whilst ruling out the possible problems. This study alms to obtain body surface motion by using the couch based computer-controlled motion phantom (CBMP) and US sensor, and to develop respiration gating techniques that can adjust patients' beds by using opposite values of the data obtained. The CBMP made to measure body surface motion is composed of a BS II microprocessor, sensor, host computer and stopping motor etc. And the program to control and operate It was developed. After the CBMP was adjusted by entering random movement data, and the phantom movements were acquired using the sensors, the two data were compared and analyzed. And then, after the movements by respiration were acquired by using a rabbit, the real-time respiration gating techniques were drawn by operating the phantom with the opposite values of the data. The result of analysing the acquisition-correction delay time for the data value shows that the data value coincided within 1% and that the acquistition-correction delay time was obtained real-time $(2.34{\times}10^{-4}sec)$. And the movement was the maximum movement was 6 mm In Z direction, In which the respiratory cycle was 2.9 seconds. This study successfully confirms the clinical application possibility of respiration gating techniques by using a CBWP and sensor.

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The Change of The Effect on The Subcutaneous Fat Area and Visceral Fat Area by The Functional Electrical Stimulation and Aerobic Exercise (기능적 전기 자극과 유산소 운동이 복부비만의 피하지방과 내장지방에 미치는 효과)

  • Oh Sung-tae;Lee Mun-hwan;Park Rae-Joon
    • The Journal of Korean Physical Therapy
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    • v.16 no.1
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    • pp.85-123
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    • 2004
  • Back ground : Subcutaneous fat area is the main factor involved in replacement disease and arteriosclerosis. Simple weight control is the appropriate medical treatment. It's understood that weight reduction does not only reduce the fat concentrations in blood but also reduces blood pressure, improves glucose levels in diabetes patients and reduces incidents of heart disease. there are several methods for reducing fat in the abdominal region but their effectiveness is not folly understood. one method is electrical stimulation of the problem areas. Method : From May 1st 2002 to October 31st. The 15 subjects who received medical examination were aged between 25 and 53 and were of mixed gender. The subjects were divided into two groups one to received functional electrical stimulation and the other a control group. Using Broca's criterion for judging fat grades. I analysed the differences between the two groups before and after the treatment. Subjects received functional electrical stimulation on the abdominal muscle intensity 50Hz. They received this treatment 4 days a week for 40 minutes a day. In the case of aerobic exercise, at the Treadmill, we used it with the intensity of $75\%$ maximum heart rate (220-age). Result 1)After functional electrical stimulation in the case of male subjects, the weight was reduced 1.93kg, obesity $2.60\%$, fat mass 2.73kg, Percent body fat $4.40\%$, waist circumference 6.53cm, circumference of hips 5.53cm. On the other side, the quality of muscle was increased at the rate of 1.03kg, but it's not attentional level. The subcutaneous fat area was reduced by $26.63cm^2$, the visceral fat area was reduced by $43.00cm^2$, In the female subjects, we can see the reduction of fat grade by $26.63cm^2$, the quantity of body fat by 1.5kg, percent body fat by $1.77\%$, circumference of waist by 4.02cm, circumference of hips by 3.67cm, weight by 1.40kg but was increased 0.72kg at the quantity of muscles. We can see the reduction also in the subcutaneous fat area $24.03cm^2$, the visceral fat area by $25.36cm^2$. 2)After aerobic exercise, on the male subjects, we can see reduction of weight by 3.36kg, obesity by $4.00\%$, fat mass by 2.83kg and we can see increase at the soft lean mass by 2.96kg, but we can see reduction, the percent body fat by $3.03\%$, fat distribution by $0.023\%$, circumference of waist by 3.10cm, circumference of hips by 2.23cm. The female subjects show a reduction in the weight by 2.48kg, percent body fat by $2.20\%$, show an increase in the soft lean mass by 1.54kg. We can see a reduction in the quantity of fat mass by 2.32kg, the percent body fat by $2.80\%$, the circumference of waist by 2.16cm, the circumference of hips by 2.68cm, the fat distribution by $0.016\%$, the subcutaneous fat area by $15.25cm^2$ the visceral fat area by $11.52cm^2$. After aerobic exercise, we can't see the attentional change at the total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol. 3)After the application of functional electrical stimulation and aerobic exercise, in result of measurement on the body ingredient, we could see the weight reduction and increase the quantity of muscle with the male group who exercised aerobic. We can see the attentional rate on the electrical stimulation about abdominal fat rate, circumference of waist, circumference of hips. The other hand, I couldn't see the attentional differences between the two groups in the rate of fatness and quantity of body fat and the rate of body fat. There isn't any attentional difference in the area of fat under skin, on the contrary, There is attentional difference in the fat in the internal organs area at the electrical stimulation site. We can't see the attentional change of total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol between electrical stimulation and aerobic exercise. 4)After execution of functional electrical stimulation and aerobic exercise, in result of measurement on change of body ingredient among female objects, We could see weight reduction, increase at muscle quantity in the aerobic exercise group. We could see the attentional differences in the rate of fatness, the rate of abdominal region, the circumference which received electrical stimulation. But, we couldn't see the attentional differences between two groups in the quantity of body fatness, the circumference of hips. The subcutaneous fat area doesn't show the attentional differences. On the Contrary, we could see lots of differences in the visceral fat area of the electrical stimulation group. Conclusion The results show that functional electrical stimulation and aerobic exercise have insignificant differences when if comes to total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol. Though there is affirmative change in body ingredient after both electrical stimulation and aerobic exercise. Functional electrical stimulation is more effective on the subcutaneous fat area and in changing visceral fat area. There fore. It is concluded that the physical therapy is more effective in the treatment of abdominal fatness.

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Role of Growth Factors and Cytokines on Bleomycin Induced Pulmonary Fibrosis (Bleomycin 유도 폐 섬유화에 있어서 성장인자 및 Cytokine의 역할)

  • Lee, Yong-Hee;Jung, Soon-Hee;Ahn, Chul-Min;Kim, Sung-Kyu;Cho, Sang-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.4
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    • pp.871-888
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    • 1997
  • Background : It is now thought that the earliest manifestation of idiopathic pulmonary fibrosis is alveolitis, that is, an accumulation of inflammatory and immune effector cells within alveolar walls and spaces. Inflammatory cells including alveolar macrophages and resident normal pulmonary tissue cells participate through the release of many variable mediators such as inflammatory growth factors and cytokines, which contribute to tissue damage and finally cause chronic pulmonary inflammation and fibrosis. This study was performed to investigate the source and distribution pattern of transforming growth factor-${\beta}_1$(TGF-${\beta}_1$), platelet derived growth factor(PDGF), basic fibroblast growth factor(bFGF), interleukin 1(IL-1), interleukin 6(IL-6), tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and the role of these mediators on bleomycin(BLM)-induced pulmonary injury and fibrosis in rats. Method : Wistar rats were divided into three groups(control group, BLM treated group, BLM and vitamine E treated group). Animals were sacrificed periodically at 1, 2, 3, 4, 5, 7, 14, 21, 28 days after saline or BLM administration. The effects were compared to the results of bronchoalveolar lavage fluid analysis, light microscopic findings, immunohistochemical stains for six different mediators(TGF-${\beta}_1$, PDGF, bFGF, IL-1, IL-6 and TNF-$\alpha$) and mRNA in situ hybridization for TGF-${\beta}_1$. Results : IL-1 and IL-6 are maximally expressed at postbleomycin 1~7th day which are mainly produced by neutrophils and bronchiolar epithelium. It is thought that they induce recruitment of inflammatory cells at the injury site. The expression of IL-1 and IL-6 at the bronchiolar epithelium within 7th day is an indirect evidence of contribution of bronchiolar epithelial cells to promote and maintain the inflammatory and immune responses adjacent to the airways. TNF-$\alpha$ is mainly produced by neutrophils and bronchiolar epithelial cells during 1~5th day, alveolar macrophages during 7~28th day. At the earlier period, TNF-$\alpha$ causes recruitment of inflammatory cells at the injury site and later stimulates pulmonary fibrosis. The main secreting cells of TGF-${\beta}_1$ are alveolar macrophages and bronchiolar epithelium and the target is pulmonary fibroblasts and extracellular matrix. TGF-${\beta}_1$ and PDGF stimulate proliferation of pulmonary fibroblasts and TGF-${\beta}_1$ and bFGF incite the fibroblasts to produce extracellular matrix. The vitamine E and BLM treated group shows few positive cells(p<0.05). Conclusion : After endothelial and epithelial injury, the neutrophils and bronchiolar epithelium secrete IL-1, IL-6, TNF-$\alpha$ which induce infiltration of many neutrophils. It is thought that variable enzymes and $O_2$ radicals released by these neutrophils cause destruction of normal lung architecture and progression of pulmonary fibrosis. At the 7~28th day, TGF-${\beta}_1$, PDGF, bFGF, TNF-$\alpha$ secreted by alveolar macrophages sting pulmonary fibroblasts into proliferating with increased production of extracellular matrix and finally, they make progression of pulmonary fibrosis. TNF-$\alpha$ compares quite important with TGF-${\beta}_1$ to cause pulmonary fibrosis. Vitamine E seems to decrease the extent of BLM induced pulmonary fibrosis.

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Evaluation of the Usefulness of Restricted Respiratory Period at the Time of Radiotherapy for Non-Small Cell Lung Cancer Patient (비소세포성 폐암 환자의 방사선 치료 시 제한 호흡 주기의 유용성 평가)

  • Park, So-Yeon;Ahn, Jong-Ho;Suh, Jung-Min;Kim, Yung-Il;Kim, Jin-Man;Choi, Byung-Ki;Pyo, Hong-Ryul;Song, Ki-Won
    • The Journal of Korean Society for Radiation Therapy
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    • v.24 no.2
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    • pp.123-135
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    • 2012
  • Purpose: It is essential to minimize the movement of tumor due to respiratory movement at the time of respiration controlled radiotherapy of non-small cell lung cancer patient. Accordingly, this Study aims to evaluate the usefulness of restricted respiratory period by comparing and analyzing the treatment plans that apply free and restricted respiration period respectively. Materials and Methods: After having conducted training on 9 non-small cell lung cancer patients (tumor n=10) from April to December 2011 by using 'signal monitored-breathing (guided- breathing)' method for the 'free respiratory period' measured on the basis of the regular respiratory period of the patents and 'restricted respiratory period' that was intentionally reduced, total of 10 CT images for each of the respiration phases were acquired by carrying out 4D CT for treatment planning purpose by using RPM and 4-dimensional computed tomography simulator. Visual gross tumor volume (GTV) and internal target volume (ITV) that each of the observer 1 and observer 2 has set were measured and compared on the CT image of each respiratory interval. Moreover, the amplitude of movement of tumor was measured by measuring the center of mass (COM) at the phase of 0% which is the end-inspiration (EI) and at the phase of 50% which is the end-exhalation (EE). In addition, both observers established treatment plan that applied the 2 respiratory periods, and mean dose to normal lung (MDTNL) was compared and analyzed through dose-volume histogram (DVH). Moreover, normal tissue complication probability (NTCP) of the normal lung volume was compared by using dose-volume histogram analysis program (DVH analyzer v.1) and statistical analysis was performed in order to carry out quantitative evaluation of the measured data. Results: As the result of the analysis of the treatment plan that applied the 'restricted respiratory period' of the observer 1 and observer 2, there was reduction rate of 38.75% in the 3-dimensional direction movement of the tumor in comparison to the 'free respiratory period' in the case of the observer 1, while there reduction rate was 41.10% in the case of the observer 2. The results of measurement and comparison of the volumes, GTV and ITV, there was reduction rate of $14.96{\pm}9.44%$ for observer 1 and $19.86{\pm}10.62%$ for observer 2 in the case of GTV, while there was reduction rate of $8.91{\pm}5.91%$ for observer 1 and $15.52{\pm}9.01%$ for observer 2 in the case of ITV. The results of analysis and comparison of MDTNL and NTCP illustrated the reduction rate of MDTNL $3.98{\pm}5.62%$ for observer 1 and $7.62{\pm}10.29%$ for observer 2 in the case of MDTNL, while there was reduction rate of $21.70{\pm}28.27%$ for observer 1 and $37.83{\pm}49.93%$ for observer 2 in the case of NTCP. In addition, the results of analysis of correlation between the resultant values of the 2 observers, while there was significant difference between the observers for the 'free respiratory period', there was no significantly different reduction rates between the observers for 'restricted respiratory period. Conclusion: It was possible to verify the usefulness and appropriateness of 'restricted respiratory period' at the time of respiration controlled radiotherapy on non-small cell lung cancer patient as the treatment plan that applied 'restricted respiratory period' illustrated relative reduction in the evaluation factors in comparison to the 'free respiratory period.

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Comparison of Effects of Normothermic and Hypothermic Cardiopulmonary Bypass on Cerebral Metabolism During Cardiac Surgery (체외순환 시 뇌 대사에 대한 정상 체온 체외순환과 저 체온 체외순환의 임상적 영향에 관한 비교연구)

  • 조광현;박경택;김경현;최석철;최국렬;황윤호
    • Journal of Chest Surgery
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    • v.35 no.6
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    • pp.420-429
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    • 2002
  • Moderate hypothermic cardiopulmonary bypass (CPB) has commonly been used in cardiac surgery. Several cardiac centers recently practice normothermic CPB in cardiac surgery, However, the clinical effect and safety of normothermic CPB on cerebral metabolism are not established and not fully understood. This study was prospectively designed to evaluate the clinical influence of normothermic CPB on brain metabolism and to compare it with that of moderate hypothermic CPB. Material and Method: Thirty-six adult patients scheduled for elective cardiac surgery were randomized to receive normothermic (nasopharyngeal temperature >34.5 $^{\circ}C$, n=18) or hypothermic (nasopharyngeal temperature 29~3$0^{\circ}C$, n=18) CPB with nonpulsatile pump. Middle cerebral artery blood flow velocity (VMCA), cerebral arteriovenous oxygen content difference (CAVO$_{2}$), cerebral oxygen extraction (COE), modified cerebral metabolic rate for oxygen (MCMRO$_{2}$), cerebral oxygen transport (TEO$_{2}$), cerebral venous desaturation (oxygen saturation in internal jugular bulb blood$\leq$50 %), and arterial and internal jugular bulb blood gas analysis were measured during six phases of the operation: Pre-CPB (control), CPB-10 min, Rewarm-1 (nasopharyngeal temperature 34 $^{\circ}C$ in the hypothermic group), Rewarm-2 (nasopharyngeal temperature 37 $^{\circ}C$ in the both groups), CPB-off and Post-CPB (skin closure after CPB-off). Postoperaitve neuropsychologic complications were observed in all patients. All variables were compared between the two groups. Result: VMCA at Rewarm-2 was higher in the hypothermic group (153.11$\pm$8.98%) than in the normothermic group (131.18$\pm$6.94%) (p<0.05). CAVO$_{2}$ (3.47$\pm$0.21 vs 4.28$\pm$0.29 mL/dL, p<0.05), COE (0.30$\pm$0.02 vs 0.39$\pm$0.02, p<0.05) and MCMRO$_{2}$ (4.71 $\pm$0.42 vs 5.36$\pm$0.45, p<0.05) at CPB-10 min were lower in the hypothermic group than in the normothermic group. The hypothermic group had higher TEO$_{2}$ than the normothermic group at CPB-10 (1,527.60$\pm$25.84 vs 1,368.74$\pm$20.03, p<0.05), Rewarm-2 (1,757.50$\pm$32.30 vs 1,478.60$\pm$27.41, p<0.05) and Post-CPB (1,734.37$\pm$41.45 vs 1,597.68$\pm$27.50, p<0.05). Internal jugular bulb oxygen tension (40.96$\pm$1.16 vs 34.79$\pm$2.18 mmHg, p<0.05), saturation (72.63$\pm$2.68 vs 64.76$\pm$2.49 %, p<0.05) and content (8.08$\pm$0.34 vs 6.78$\pm$0.43 mL/dL, p<0.05) at CPB-10 were higher in the hypothermic group than in the normothermic group. The hypothermic group had less incidence of postoperative neurologic complication (delirium) than the normothermic group (2 vs 4 patients, p<0.05). Lasting periods of postoperative delirium were shorter in the hypothermic group than in the normothermic group (60 vs 160 hrs, p<0.01). Conclusion: These results indicate that normothermic CPB should not be routinely applied in all cardiac surgery, especially advanced age or the clinical situations that require prolonged operative time. Moderate hypothermic CPB may have beneficial influences relatively on brain metabolism and postoperative neuropsychologic outcomes when compared with normothermic CPB.

Physico-chemical Properties and Utilization of Sarcoplasmic Proteins for the Determination of End-point Cooking Temperatures of Ground Pork Hams Containing Salt and Fat (식염 및 지방을 함유한 분쇄돈육의 이화학적 성상 및 최종가열온도 측정을 위한 근장단백질의 이용)

  • Kang, S.M.;Chin, K.B.;Cho, S.H.;Lee, J.M.
    • Journal of Animal Science and Technology
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    • v.46 no.1
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    • pp.83-90
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    • 2004
  • Processed meals, such as a ground meat and hamburger patty, are required to ensure that no pathogens remain in the final products. However, there was no rapid method available to verify that the recommended end-point cooking temperature(EPT) was reached. Thus, the objective of this study was to rapidly determine EPT of ground pork hams using sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SOS-PAGE), based on the disappearance of sarcoplasmic proteins after cooking. Fresh pork hams were added two levels of salt(0, 2%) and fat(15, 25%) combinations, and stored in refrigerator overnight, and cooked to internal cooking temperatures of $64^{\circ}C$ to $74^{\circ}C$ with $2^{\circ}C$ increments. Cooked pork hams were measured cooking loss(CL, %), protein solubility(PS) and SOS-PAGE. CL(%) was reduced with the addition of 2% salt, as compared to the control, regardless of fat contents. It was also increased with increasing eooking temperature. Protein solubility was affected by the cooking temperature, resulting in reduced PS up to $64^{\circ}C$(P < 0.05), but remained constant higher than $68^{\circ}C$. In SOS-PAGE analysis, protein bands with the molecular weights of 36 and 66 kDa were affected by the addition of salt and fat combinations. regardless of treatments. These protein fractions were decreased gradually with increased cooking temperatures up to $68^{\circ}C$ ${\sim}$ $70^{\circ}C$ and might be good indicators for the determination of EPT in ground pork hams.

Optimal Medium Composition of Cauliflower Mushroom (Sparassis latifolia) Cultivation Using Douglas Fir Wood Chip and Comparison of The β-glucan Contents of The Fruiting Body (미송톱밥을 이용한 꽃송이버섯 재배의 최적 배지 조성과 버섯의 β-glucan 함량 비교)

  • Wang, Seung-Jin;Kim, Hyun-Seok;Wi, An-Jin;Yoon, Byung-Sun;Park, Whoa-Shig;Park, Hyeong-Ho;Oh, Deuk-Sil
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.4
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    • pp.428-438
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    • 2014
  • Functional effects of cauliflower mushroom (Sparassis latifolia) have been magnified by various media and internal and external research papers, recently. So, optimum condition of wood chip particle size and cultivation method of high ${\beta}$-glucan content for bulk cultivation generalization of cauliflower mushroom farms researched. As a result, T7 (1~2 mm 25%, 2~4 mm 50%, over 4 mm 25%) media as mixed media of certain ratio of particle size, showed excellent growth at $11.5{\pm}1.0$ cm / 44 days. Also, production of fruit body found higher than control and marketable pileus part took 85% ratio. The ${\beta}$-glucan content at media composition condition showed 1.4~2.4 times higher content in stipe part than pileus part. Also, PCF300 medium found 59.5% highest ${\beta}$-glucan content in stipe part. While ${\beta}$-glucan content showed 33.0% low content in pileus part. Therefore it needed additional study that ${\beta}$-glucan content improved in pileus part. In conclusion, production of high ${\beta}$-glucan content cauliflower mushroom was possible by T7 condition (wood chip particle size: 1~2 mm 25%, 2~4 mm 50% and over 4 mm 25%, composition: corn powder, flour and 300 ppm yeast).

PSYCHOPATHOLOGY IN ADOLESCENTS WITH PARENT ABUSE (부모학대 청소년의 정신병리)

  • Kwak, Young-Sook;Bang, Hyun-Soog
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.9 no.1
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    • pp.13-25
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    • 1998
  • Aim:We think that the most important etiology in parent abuse is the psychodynamic and psychopathology in the family. So, we investigated the adolescents being admitted in SNMH, whose chief complaints were parent abuse. We were trying to explore families psychodynamic and psychopathology, especially mother-child interaction and to differentiate them in according to developmental psychopathology. Method:Our objects were the adolescent patients admitted in SNMH from 1987 to 1997 because they attacked parents verbally and physically. We examined 21 adolescents except those with psychosis, organic mental disorder, autism and mental retardation by means of interview or chart review. Result and Conclusion:The number of male patients was 14 and the number of female patients was 7. The most common diagnosis was conduct disorder and borderline personality disorder. The mean age was in the mid-teens. We observed 4 subgroups that were divided developmentally in object relation. 1) Symbiotic group with mother:(1) They did not separate and remain in symbiotic relationships with their mothers based on insecure attachment. Fathers were abscent emotionally and physically, and their mothers were prominent in close relationships with the patients in their family , where as the patients were the only man in the family. Adolescents entered the second separation-individuation. They expressed anger and internal tension involved with the close attachment with their mothers and also attempted separation from their mothers through physically attacking them. (2) These patients had suffered from physical illness and developmental delay since birth. Therefore the parents overprotected their children. The children had persistent infantile omnipotence and fantasies of power, so they could not deal with unrealistic states, adapt to reality, and depended on their parents overtly. They easily acted out unless their demands were fulfilled. 2) Borderline personality disorder:We observed deficiencies in care taking. Their parents had personality problems and immaturity. They coulden’t help their children to be separated in the rapproachment phase. Their conflict about dependence-independence was revived in the second separation-individuation adolescent period. We understand parent abuse as an attempt to overcome the conflict. 3) Conduct disorder:They did not build up basic attachment with their parents. They think of their parents as only a means of fulfilling their needs. When patients’ need were not fulfilled and remained in a conflicted state, they attacked their parents, unable to control their aggressions and impulses.

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Stabilization and Release Behavior of W1/O/W2-Type Multiple Emulsions Using Various Block Copolymer Emulsifier and Stabilizer (다양한 Block Copolymer를 유화제 및 안정화제로 사용한 W1/O/W2-Type 다중에멀젼의 방출거동 및 안정성)

  • Haw, Jung-Rim;Kim, Cheol-Hun
    • Applied Chemistry for Engineering
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    • v.8 no.4
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    • pp.560-567
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    • 1997
  • A new approach to obtain stable $W_1/O/W_2$ multiple emulsions has been studied ; The basis of the interfacial interaction between a PCL-PEO-PCL triblock copolymer and a lipophilic emulsifier in the dispersed oil phase was examined. $W_1/O/W_2$ multiple emulsions were prepared by the two-step method. Arlacel P-l35 was used as a liphophilic emulsifier and Synperonic PE/F 127 as a hydrophilic one. Eutanol-G was used as an oil phase. NaCl was encapsulated within the multiple emulsion droplets as the internal marker and its release rate studies were carried out. The suability of the multiple emulsions have been assessed by measuring Separation Ratios(%) and microscopic observations. The release of NaCl was significantly reduced in $W_1/O/W_2$ multiple emulsions containing PCL-PEO-PCL triblock copolymer(2k-4k-2k or 6k-4k-6k) in the oil phase. It may be concluded that the copolymer and the emulsifier form effective interfacial complex to enhance stability and to control the release rate. The effective diffusion coefficients of the NaCl were estimated as $2.64{\times}10^{-15}s$and $3.23{\times}10^{-16}gcm^2/s$ for the $W_1/O/W_2$ multiple emulsion containing 1.2 wt % of PCL-PEO-PCL triblock copolymers with compositions of 2k-4k-2k and 6k-4k-2k, respectively. The rate of release decreased with the increase of the initial concentration of NaCl. The results were examined in view of Higuchi mechanism. A kinetic model which is similar to the model for release of dispersed drugs from a polymeric matrix was found to be suitable for the release of NaCl from $W_1/O/W_2$ multiple emulsions.

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Effect of Humidified High Flow CO2 Gas Insufflation on the Coronary Endothelium (가습화한 고유량의 이산화탄소가스 통기가 관상동맥 내피세포층에 미치는 영향)

  • 최재성;김준성;서정욱;김기봉
    • Journal of Chest Surgery
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    • v.37 no.2
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    • pp.131-138
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    • 2004
  • High-flow gas insufflation to get a bloodless field during off-pump coronary artery bypass may have adverse effects on the coronary endothelium. This study was designed (1) to elucidate the effect of carbon dioxide gas insufflations on the coronary endothelium at different flow rates and (2) to assess the protective effect of humidifcation against the coronary endothelial damage. Material and Method: In nine pigs, the left anterior descending coronary artery (LAD) was exposed after a median sternotomy. The LAD was divided into 4 segments and a coronary arteriotomy was made in each LAD segment in the beating heart. The far distal arteriotomy was exposed to room air for 10 minutes and was harvested as a control. Non-humidified carbon dioxide gas at a continuous flow rate of 5 L/min (Group I), humidified carbon dioxide gas at a continuous flow rate of 5 L/min (Group II), and humidified carbon dioxide gas at a continuous flow rate of 10 L/min (Group III) were insufflated for 10 minutes on each coronary arteriotomy site, respectively. After harvesting the coronary segments, hematoxylin-eosin staining, elastic fiber staining, and immunostaining with a CD34 monoclonal antibody were performed to evaluate the depth of endothelial damage and to count the residual endothelial cells, Result: In all three groups (Group I, II, and III), internal elastic laminae were preserved, however, the endothelial layers were significantly damaged by carbon dioxide gas insufflation. The mean percentages of remaining endothelial cells were 20,9$\pm$16.7%, 39.3$\pm$19.6%, and 6.8$\pm$5.3%, in groups I, II, and III, respectively. The percentages of remaining cells were significantly higher in group II than in groups I and III (p=0.008). The percentages of remaining cells were significantly higher in group I than in group III (p=0.008). Conclusions: The harmful effect of carbon dioxide gas insufflation on the coronary endothelium was dependent on the flow rate. The addition of humidification did not protect the coronary endothelium from denudation injury caused by high flow carbon dioxide gas insufflations.