A Differential Current-to-Time Converter for ISFET Biosensors

Chang-Su Won,Won-Sup Chung 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7

The differential current-to-time converter consists of a ramp voltage generator, an ISFET biosensor, a reference FET (REFET), two gain-adjustable current amplifiers, two current-tunable Schmitt triggers, and two logic gates. The design principle is to apply a ramp voltage to each input of the two current-tunable Schmitt triggers whose threshold voltages are proportional to the drain current values of the ISFET biosensors. A proposed circuit converts a current change in the ISFET biosensor into its equivalent pulse width change. A prototype circuit built using discrete components exhibit a conversion sensitivity amounting to 645.54 ㎲/pH s μ over pH variation range of 1-14 and a linearity error less than 0.001 %.

Fluoxetine과 Haloperidol의 병합투여시 정신병리 및 추체외로 증상의 변화

이민수,한창수,김제원,원경식,곽동일,Lee, Min-Soo,Han, Chang-Su,Kim, Jae-Won,Won, Kyung-Sik,Kwak, Dong-Il 대한생물정신의학회 1997 생물정신의학 Vol.4 No.1

본 연구는 정신분열증 환자 38명을 대상으로 하여 haloperidol과 fluoxetine을 8주간 병합투여 하였고, PANSS, CGI, Simpson-Angus 척도를 투여전과 투여후 2, 4, 6, 8주에 시행하여 임상증상 및 추체외로 부작용을 평가하였다. 결과는 다음과 같다. 1) 8주간의 연구기간동안 양성, 음성증상의 유의한 변화가 없었다. 2) 8주의 연구기간동안 추체외로 부작용의 증가가 나타나지 않았다. 이는 기존 연구에서 fluoxetine에 의해 haloperidol의 혈중농도가 증가하여 효과 및 부작용이 증가한다는 연구보고와는 다르며, 이 결과는 haloperidol과 fluoxetine의 병합사용을 안전하게 할 수 있다는 것을 의미한다고 하겠다. Objectives : The authors have intended to know the drug interaction of fluoxetine and haloperidol when coadministering two drugs to the chronic schizophrenics by assessing the changes of positive, negative symptoms and extrapyramidal symptoms. Method : We selected 38 patients, the chronic schizophrenics with no physical problems. they are randomly assigned to placebo group and drug group. And then, placebo or fluoxetine 20mg were administered to the subjects of each group during 8 week period. We have assessed their psychopatholgy and extrapyramidal symptoms using Positive and Negative Syndrome Scale(PANSS), Clinical Global Impression(CGI), Simpson-Angus Scale at 0, 2, 4, 6, 8 week during the period. Results : 38 patients have completed the study during 8 weeks. 1) PANSS, CGI : no significant difference between groups and no significant change according to the times. 2) Simpson-Angus Scale : no significant changes. Conclusion : When co-administering fluoxetine and haloperidol, there were no significant changes of psychopathology and extrapyramidal symptoms. These results suggest that it is safe to coadminister fluoxetine to schizophrenic patients with haloperidol treatmemt.

만성 골수성 백혈병(Chronic Myelogenous Leukemia) 치료 중 인터페론-알파(Interferon-α)에 의한 용혈성 요독 증후군 1예

장재원,김유미,서장원,최귀숙,유수진,지현숙,유종우,박수길 대한신장학회 2002 Kidney Research and Clinical Practice Vol.21 No.2

Interferon-alpha is an established therapy for the patients with myeloproliferative disease. Unusual immune- mediated side effects have been reported during treatment. Among them, renal and cardiac toxicities are rare complications. Recently we experienced a case of hemolytic uremic syndome found in a 40-year old male undergoing interferon-alpha therapy for chronic myelogenous leukemia, chronic phase. On admission, his chief complaints were generalized edema and azotemia. Bone marrow biopsy revealed transformation into accelerated phase. bcl/abl gene was positive. Peripheral blood smear showed hemolytic anemia. Despite prompt diagnosis, institution of plasmapheresis, and steroid, his renal function did not recover, as expected. Hemolytic uremic syndrome was a chronic form of renal toxicity due to interferon- alpha. In this case, renal function did not recovered to normal level. However, early detection of renal toxicity such as proteinuria or acute tubular necrosis, and the discontinuation of interferon-alpha could achieve the recovery of normal renal function. Therefore, periodic examination of renal function should be performed in the patients with the use of long-term interferon-alpha. (Korean J Nephrol 2002; 21(2):341-347)

사염화탄소 투여 흰쥐에서 간섬유화 진행에 따른 Propranolol 의 약동학적 지표들의 변화

이민호,강주섭,강문수,윤병철,이오영,함준수,변재원,윤창옥 대한간학회 2001 Clinical and Molecular Hepatology(대한간학회지) Vol.7 No.2

Background/Aims : This study was designed to determine the effect of hepatic fibrotic severity on pharmacokinetics of propranolol in CC1q - treated rats. Methods - 1 mL/kg of 10% CC14 in olive oil was injected intramuscularly to rats twice weekly for 4, 6, 8 and 10 weeks, respectively (n=6). Control (n=6) was a sham - injected equal dose of olive oil for 10 weeks. After intravenous bolus injection of 2 mg/kg propranolol to rats, the serum propranolol concentrations were analyzed for 4 hours at various time points by a HPLC - fluorimetric system, and pharmacokinetic parameters such as Co, MRT, AUC, Vdss, tl/2(p) and CLp were determined. Then, a small amount of hepatic tissue was obtained and subjected to determination of the hepatic 4 - hydroxyproline content, which confirmed the hepatic fibrotic severity. Results : The serum concentrations of propranolol at 0.5, 1, 2 and 4 hours were significantly increased in CC1q-treated rats (p$lt;0.01). In proportion to the duration of CC4 treatment, Co and AUC were significantly increased, and Vdss and CLp were significantly decreased (p$lt;0.001). But MRT and t1/2(β) were not significantly changed. The hepatic 4 -hydroxyproline content was gradually increased in CC4-treated rats (p$lt;0.001). Conclusion - Gradual changes in pharmacokinetic parameters of propranolol were seen to be dependent on the hepatic fibrotic severity. We suggest that gradual dosage modification, according to their hepatic fibrotic severity, is necessary for many drugs administered to patients with chronic liver disease.(Korean J Hepatol 2001;7:181-188)

pH-LAPS의 제작 및 그 특성

장수원,고광락,강신원 경북대학교 센서기술연구소 1997 센서技術學術大會論文集 Vol.8 No.1

A silicon-based light addressable potentiometric sensor (LAPS) to detect the pH changes was developed. The pH-LAPS structure is Si_(3)N_(4)/SiO_(2)/Si layers, and SiO_(2) layer and Si_(3)N_(4) thin flim which is used as a pH-sensing layer had been grown by dry oxidation and LPCVD method, respectively. We excited photocurrent in the pH-LAPS device by illuminating 10kHz alternative light upon the back of it. The phtocurrent changes according to the potential change, varied by the pH, on the interface between electrolyte and insulator. The fabricated pH-LAPS shows good sensitivity(about 56mV/pH) and lineality in the range from pH 2 to pH 11.

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

항-E 항체에 의한 급성 신부전을 동반한 지연성 용혈성 수혈 부작용 1례

강문수,변재원,윤창옥,김인순 大韓輸血學會 1999 大韓輸血學會誌 Vol.10 No.2

Comparison of changes in retentive force of three stud attachments for implant overdentures

Su-Min Kim,Jae-Won Choi,Young-Chan Jeon,Chang-Mo Jeong,Mi-Jung Yun,So-Hyoun Lee,Jung-Bo Huh 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.4

PURPOSE The aim of this study was to compare the changes in retentive force of stud attachments for implant overdentures by in vitro 2-year-wear simulation. MATERIALS AND METHODS Three commercially available attachment systems were investigated: Kerator blue, O-ring red, and EZ lock. Two implant fixtures were embedded in parallel in each custom base mounting. Five pairs of each attachment system were tested. A universal testing machine was used to measure the retentive force during 2500 insertion and removal cycles. Surface changes on the components were evaluated by scanning electron microscopy (SEM). A Kruskal-Wallis test, followed by Pairwise comparison, was used to compare the retentive force between the groups, and to determine groups that were significantly different (α<.05). RESULTS A comparison of the initial retentive force revealed the highest value for Kerator, followed by the O-ring and EZ lock attachments. However, no significant difference was detected between Kerator and O-ring (P>.05). After 2500 insertion and removal cycles, the highest retention loss was recorded for O-ring, and no significant difference between Kerator and EZ lock (P>.05). Also, Kerator showed the highest retentive force, followed by EZ lock and O-ring, after 2500 cycles (P<.05). Based on SEM analysis, the polymeric components in O-ring and Kerator were observed to exhibit surface wear and deformation. CONCLUSION After 2500 insertion and removal cycles, all attachments exhibited significant loss in retention. Mechanism of retention loss can only be partially explained by surface changes.

게껍질 Chitin 및 Chitosan의 소화관내 기능성에 관한 in vitro 연구

장현주,전동원,이서래 이화여자대학교 생명과학연구소 1994 생명과학연구논문집 Vol.5 No.-

반응 조건을 달리하여 게껍질에서 chitin을 추출하고 이를 탈아세틸화하여 chitosan을 제조하였으며, 이들의 물리, 화학적 특성과 소호관내 기능성을 in vitro법으로 실시하였다. 이들 chitin질의 bulk density는 127~208㎎/㎖, 정도는 0.1% chitin의 경우 80~581 cP, 0.5% chitosan은 80~3,670 cP로 다양한 수치를 나타냈으며, chitosan의 탈아세틸화도는 81~93%로 비교적 높았다. Chitosan 제조시의 알칼리 농도와 반응 온도가 일정할 때 반응 시간이 경과할수록 탈아세틸화도는 증가하였고, 점도는 감소하는 경향을 보였다. Chitin질의 보수력은 온도 상승에 따라 약간 상승하였고, 37℃ 에서 chitosan D가 가장 높았으며, bulk density가 낮을수록 높은 보수력을 나타냈다. Glucose 흡수 억제 효과는 bulk density가 낮고 보수력이 큰 chitin질이 더 컸고 chitosan D가 가장 높은 38%를 나타냈다. Chitin질의 bile acid 흡수억제 효과는 투석 1시간 후에 15~34%를 나타냈고, pectin은 39%, cellulose는 9%를 나타냈으며 chitosan D는 3% 농도에서 34%의 가장 높은 억제 효과를 나타냈다. Chitin and chitosan samples prepard from crab's shells under different conditions were compared for their physicochemical properties and functionality in gastrointestinal tract by in vitro test. Their bulk density was in the range of 127~208 ㎎/㎖, and their viscosity was 80~581 cP in 0.1% chitin and 80~3,670 cP in 0.5% chitosan solution, showing a wide variation. The degree of deacetylation in chitosan samples as determined by IR spectral analysis was relatively high, showing 81~93%. At the same alkali concentration and reaction temperature, a longer reaction period gave an increased degree of deacetylation and lower viscosity. The water holding capacity of chitic substance became greater at higher soaking temperature; chitosan D at 37℃ showed the greatest value. Chitic substance with lower bulk density showed the higher water holding capacity. The retardation effect toward glucose absorption was higher in chitic substances of lower density and higher water holding capacity; chitosan D showed the highest value of 38%. The retardation index toward bile acid absorption after 1 hour dialysis was 15~34% in chitic substances, 39% in pectin and 9% in cellulose. The retarding effect showed the highest value of 34% in chitosan D at 3% concentration.

재조합 BMP-7 유전자가 전달된 HEK 293 세포에 의한 누드 마우스에서의 뼈형성

정수연,장원태,장연실,안면환,김재룡,송인환 영남대학교 의과대학 2003 Yeungnam University Journal of Medicine Vol.20 No.2

To induce bone formation at ectopic site by tissue engineering and gene therapy, we transplanted collagen sponges containing rhBMP-7 transduced HEK 293 cells in the hypodermis of nude mice. Bone formation was investigated by histological and electron microscopic method at 3, 6, and 9 weeks after transplantation. At 9 weeks after transplantation, eosinophilic bony tissue was observed in the implanted collagen sponge and was confirmed as bone tissue by Von Kossa stain. In the transmission electron microscopic observation, the cells in newly formed bone tissue had eccentrically located nucleus and well developed rough endoplasmic reticulum (rER). Therefore, the cells were evaluated as osteoblasts. Those results suggest that it is possible to form a bone tissue in the ectopic site by transplantation of rhBMP-7 transduced HEK 293 cells. This will be contributed to push more advanced gene therapy for bone formation. However, the HEK 293 cell is unable to apply to the clinical gene therapy. Therefore it is worth to find more compatible cells for clinical application. In addition, collagen sponge is considered as an excellent scaffold and/or carrier for gene therapy and a good biomaterial for tissue engineering.