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Evaluating the usefulness of BinkieRTTM (oral positioning stent) for Head and Neck Radiotherapy (두경부암 환자 방사선 치료 시 BinkieRTTM(구강용 고정장치)에 대한 유용성 평가)

  • GyeongJin Lee;SangJun Son;GyeongDal Lim;ChanYong Kim;JeHee Lee
    • The Journal of Korean Society for Radiation Therapy
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    • v.34
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    • pp.21-30
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    • 2022
  • Purpose: The purpose of this study is to evaluate the effectiveness of oral positioning stent, the BinkieRTTM in radiation treatment for head and neck cancer patients in terms of tongue positions reproducibility, tongue doses and material properties. Materials and Methods: 24 cases using BinkieRTTM during radiation treatments were enrolled. The tongue was contoured on planning CT and CBCT images taken every 3 days during treatment, and then the DSC and center of tongue shift values were analyzed to evaluate the reproducibility of the tongue. The tongue dose was compared in terms of dose distribution when using BinkieRTTM and different type of oral stents (mouthpiece, paraffin wax). Randomly selected respective 10 patients were measured tongue doses of initial treatment plan for nasal cavity and unilateral parotid cancer. Finally, In terms of material evaluation, HU and relative electron density were identified in RTPS. Results: As a result of DSC analysis, it was 0.8 ± 0.07, skewness -0.8, kurtosis 0.61, and 95% CI was 0.79~0.82. To analyze the deviation of the central tongue shift during the treatment period, a 95% confidence interval for shift in the LR, SI, and AP directions were indicated, and a one-sample t-test for 0, which is an ideal value in the deviation(n=144). As a result of the t-test, the mean and SD in the LR and SI directions were 0.01 ± 0.14 cm (p→.05), 0.03 ± 0.25 cm (p→.05), and -0.08 ± 0.25 cm (p ←.05) in the AP direction. In the case of unilateral parotid cancer patients, the Dmean to the tongue of patients using BinkieRTTM was 16.92% ± 3.58% compared to the prescribed dose, and 23.99% ± 10.86% of patients with Paraffin Wax, indicating that the tongue dose was relatively lower when using BinkieRTTM (p←.05). On the other hand, among nasal cavity cancer patients, the Dmean of tongue dose for patients who used BinkieRTTM was 4.4% ± 5.6%, and for those who used mouthpiece, 5.9% ± 6.8%, but it was not statistically significant (p→.05). The relative electron density of Paraffin Wax, BinkieRTTM and Putty is 0.94, 0.99, 1.26 and the mass density is 0.95, 0.99 and 1.32 (g/cc), Transmission Factor is 0.99, 0.98, 0.96 respectively. Conclusion: The result of the tongue DSC analysis over the treatment period was about 0.8 and Deviation of the center of tongue shifts were within 0.2 cm, the reproducibility was more likely excellent. In the case of unilateral head and neck cancer patients, it was found that the use of BinkieRTTM rather than Paraffin Wax or Putty can reduce the unnecessary dose irradiated to the tongue. This study might be useful to understand of BinkieRTTM's properties and advantages. And also it could be another considered option as oral stent to keep the reproducibility of tongue and reducing dose during head and neck radiation treatments.

The Precision Test Based on States of Bone Mineral Density (골밀도 상태에 따른 검사자의 재현성 평가)

  • Yoo, Jae-Sook;Kim, Eun-Hye;Kim, Ho-Seong;Shin, Sang-Ki;Cho, Si-Man
    • The Korean Journal of Nuclear Medicine Technology
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    • v.13 no.1
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    • pp.67-72
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    • 2009
  • Purpose: ISCD (International Society for Clinical Densitometry) requests that users perform mandatory Precision test to raise their quality even though there is no recommendation about patient selection for the test. Thus, we investigated the effect on precision test by measuring reproducibility of 3 bone density groups (normal, osteopenia, osteoporosis). Materials and Methods: 4 users performed precision test with 420 patients (age: $57.8{\pm}9.02$) for BMD in Asan Medical Center (JAN-2008 ~ JUN-2008). In first group (A), 4 users selected 30 patient respectively regardless of bone density condition and measured 2 part (L-spine, femur) in twice. In second group (B), 4 users measured bone density of 10 patients respectively in the same manner of first group (A) users but dividing patient into 3 stages (normal, osteopenia, osteoporosis). In third group (C), 2 users measured 30 patients respectively in the same manner of first group (A) users considering bone density condition. We used GE Lunar Prodigy Advance (Encore. V11.4) and analyzed the result by comparing %CV to LSC using precision tool from ISCD. Check back was done using SPSS. Results: In group A, the %CV calculated by 4 users (a, b, c, d) were 1.16, 1.01, 1.19, 0.65 g/$cm^2$ in L-spine and 0.69, 0.58, 0.97, 0.47 g/$cm^2$ in femur. In group B, the %CV calculated by 4 users (a, b, c, d) were 1.01, 1.19, 0.83, 1.37 g/$cm^2$ in L-spine and 1.03, 0.54, 0.69, 0.58 g/$cm^2$ in femur. When comparing results (group A, B), we found no considerable differences. In group C, the user_1's %CV of normal, osteopenia and osteoporosis were 1.26, 0.94, 0.94 g/$cm^2$ in L-spine and 0.94, 0.79, 1.01 g/$cm^2$ in femur. And the user_2's %CV were 0.97, 0.83, 0.72 g/$cm^2$ L-spine and 0.65, 0.65, 1.05 g/$cm^2$ in femur. When analyzing the result, we figured out that the difference of reproducibility was almost not found but the differences of two users' several result values have effect on total reproducibility. Conclusions: Precision test is a important factor of bone density follow up. When Machine and user's reproducibility is getting better, it’s useful in clinics because of low range of deviation. Users have to check machine's reproducibility before the test and keep the same mind doing BMD test for patient. In precision test, the difference of measured value is usually found for ROI change caused by patient position. In case of osteoporosis patient, there is difficult to make initial ROI accurately more than normal and osteopenia patient due to lack of bone recognition even though ROI is made automatically by computer software. However, initial ROI is very important and users have to make coherent ROI because we use ROI Copy function in a follow up. In this study, we performed precision test considering bone density condition and found LSC value was stayed within 3%. There was no considerable difference. Thus, patient selection could be done regardless of bone density condition.

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Problems in the Korean National Family Planning Program (한국가족계획사업(韓國家族計劃事業)의 문제점(問題點))

  • Hong, Jong-Kwan
    • Clinical and Experimental Reproductive Medicine
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    • v.2 no.2
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    • pp.27-36
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    • 1975
  • The success of the family planning program in Korea is reflected in the decrease in the growth rate from 3.0% in 1962 to 2.0% in 1971, and in the decrease in the fertility rate from 43/1,000 in 1960 to 29/1,000 in 1970. However, it would be erroneous to attribute these reductions entirely to the family planning program. Other socio-economic factors, such as the increasing age at marriage and the increasing use of induced abortions, definitely had an impact on the lowered growth and fertility rate. Despite the relative success of the program to data in meeting its goals, there is no room for complacency. Meeting the goal of a further reduction in the population growth rate to 1.3% by 1981 is a much more difficult task than any one faced in the past. Not only must fertility be lowered further, but the size of the target population itself will expand tremendously in the late seventies; due to the post-war baby boom of the 1950's reaching reproductive ages. Furthermore, it is doubtful that the age at marriage will continue to rise as in the past or that the incidence of induced abortion will continue to increase. Consequently, future reductions in fertility will be more dependent on the performance of the national family planning program, with less assistance from these non-program factors. This paper will describe various approaches to help to the solution of these current problems. 1. PRACTICE RATE IN FAMILY PLANNING In 1973, the attitude (approval) and knowledge rates were quite high; 94% and 98% respectively. But a large gap exists between that and the actual practice rate, which is only 3695. Two factors must be considered in attempting to close the KAP-gap. The first is to change social norms, which still favor a larger family, increasing the practice rate cannot be done very quickly. The second point to consider is that the family planning program has not yet reached all the eligible women. A 1973 study determineded that a large portion, 3096 in fact, of all eligible women do not want more children, but are not practicing family planning. Thus, future efforts to help close the KAP-gap must focus attention and services on this important large group of potential acceptors. 2. CONTINUATION RATES Dissatisfaction with the loop and pill has resulted in high discontinuation rates. For example, a 1973 survey revealed that within the first six months initial loop acceptance. nearly 50% were dropouts, and that within the first four months of inital pill acceptance. nearly 50% were dropouts. These discontinuation rates have risen over the past few years. The high rate of discontinuance obviously decreases the contraceptive effectiveness. and has resulted in many unwanted births which is directly related to the increase of induced abortions. In the future, the family planning program must emphasize the improved quality of initial and follow-up services. rather than more quantity, in order to insure higher continuation rates and thus more effective contraceptive protection. 3. INDUCED ABORTION As noted earlier. the use of induced abortions has been increase yearly. For example, in 1960, the average number of abortions was 0.6 abortions per women in the 15-44 age range. By 1970. that had increased to 2 abortions per women. In 1966. 13% of all women between 15-44 had experienced at least one abortion. By 1971, that figure jumped to 28%. In 1973 alone, the total number of abortions was 400,000. Besides the ever incre.sing number of induced abortions, another change has that those who use abortions have shifted since 1965 to include- not. only the middle class, but also rural and low-income women. In the future. in response to the demand for abortion services among rural and low-income w~men, the government must provide and support abortion services for these women as a part of the national family planning program. 4. TARGET SYSTIi:M Since 1962, the nationwide target system has been used to set a target for each method, and the target number of acceptors is then apportioned out to various sub-areas according to the number of eligible couples in each area. Because these targets are set without consideration for demographic factors, particular tastes, prejudices, and previous patterns of acceptance in the area, a high discontinuation rate for all methods and a high wastage rate for the oral pill and condom results. In the future. to alleviate these problems of the methodbased target system. an alternative. such as the weighted-credit system, should be adopted on a nation wide basis. In this system. each contraceptive method is. assigned a specific number of points based upon the couple-years of protection (CYP) provided by the method. and no specific targets for each method are given. 5. INCREASE OF STERILIZA.TION TARGET Two special projects. the hospital-based family planning program and the armed forces program, has greatly contributed to the increasing acceptance in female and male sterilization respectively. From January-September 1974, 28,773 sterilizations were performed. During the same time in 1975, 46,894 were performed; a 63% increase. If this trend continues, by the end of 1975. approximately 70,000 sterilizations will have been performed. Sterilization is a much better method than both the loop and pill, in terms of more effective contraceptive protection and the almost zero dropout rate. In the future, the. family planning program should continue to stress the special programs which make more sterilizations possible. In particular, it should seek to add the laparoscope techniques to facilitate female sterilization acceptance rates. 6. INCREASE NUMBER OF PRIVATE ACCEPTORS Among the current family planning users, approximately 1/3 are in the private sector and thus do not- require government subsidy. The number of private acceptors increases with increasing urbanization and economic growth. To speed this process, the government initiated the special hospital based family planning program which is utilized mostly by the private sector. However, in the future, to further hasten the increase of private acceptors, the government should encourage doctors in private practice to provide family planning services, and provide the contraceptive supplies. This way, those do utilize the private medical system will also be able to receive family planning services and pay for it. Another means of increasing the number of private acceptors, IS to greatly expand the commercial outlets for pills and condoms beyond the existing service points of drugstores, hospitals, and health centers. 7. IE&C PROGRAM The current preferred family size is nearly twice as high as needed to achieve a stable poplation. Also, a strong boy preference hinders a small family size as nearly all couples fuel they must have at least one or more sons. The IE&C program must, in the future, strive to emphasize the values of the small family and equality of the sexes. A second problem for the IE&C program to work. with in the: future is the large group of people who approves family planning, want no more children, but do not practice. The IE&C program must work to motivate these people to accept family planning And finally, for those who already practice, an IE&C program in the future must stress continuation of use. The IE&C campaign, to insure highest effectiveness, should be based on a detailed factor analysis of contraceptive discontinuance. In conclusion, Korea faces a serious unfavorable sociodemographic situation- in the future unless the population growth rate can be curtailed. And in the future, the decrease in fertility will depend solely on the family planning program, as the effect of other socio-economic factors has already been maximumally felt. A second serious factor to consider is the increasing number of eligible women due to the 1950's baby boom. Thus, to meet these challenges, the program target must be increased and the program must improve the effectiveness of its current activities and develop new programs.

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The Ability of Anti-tumor Necrosis Factor Alpha(TNF-${\alpha}$) Antibodies Produced in Sheep Colostrums

  • Yun, Sung-Seob
    • 한국유가공학회:학술대회논문집
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    • 2007.09a
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    • pp.49-58
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    • 2007
  • Inflammatory process leads to the well-known mucosal damage and therefore a further disturbance of the epithelial barrier function, resulting abnormal intestinal wall function, even further accelerating the inflammatory process[1]. Despite of the records, etiology and pathogenesis of IBD remain rather unclear. There are many studies over the past couple of years have led to great advanced in understanding the inflammatory bowel disease(IBD) and their underlying pathophysiologic mechanisms. From the current understanding, it is likely that chronic inflammation in IBD is due to aggressive cellular immune responses including increased serum concentrations of different cytokines. Therefore, targeted molecules can be specifically eliminated in their expression directly on the transcriptional level. Interesting therapeutic trials are expected against adhesion molecules and pro-inflammatory cytokines such as TNF-${\alpha}$. The future development of immune therapies in IBD therefore holds great promises for better treatment modalities of IBD but will also open important new insights into a further understanding of inflammation pathophysiology. Treatment of cytokine inhibitors such as Immunex(Enbrel) and J&J/Centocor(Remicade) which are mouse-derived monoclonal antibodies have been shown in several studies to modulate the symptoms of patients, however, theses TNF inhibitors also have an adverse effect immune-related problems and also are costly and must be administered by injection. Because of the eventual development of unwanted side effects, these two products are used in only a select patient population. The present study was performed to elucidate the ability of TNF-${\alpha}$ antibodies produced in sheep colostrums to neutralize TNF-${\alpha}$ action in a cell-based bioassay and in a small animal model of intestinal inflammation. In vitro study, inhibitory effect of anti-TNF-${\alpha}$ antibody from the sheep was determined by cell bioassay. The antibody from the sheep at 1 in 10,000 dilution was able to completely inhibit TNF-${\alpha}$ activity in the cell bioassay. The antibodies from the same sheep, but different milkings, exhibited some variability in inhibition of TNF-${\alpha}$ activity, but were all greater than the control sample. In vivo study, the degree of inflammation was severe to experiment, despite of the initial pilot trial, main trial 1 was unable to figure out of any effect of antibody to reduce the impact of PAF and LPS. Main rat trial 2 resulted no significant symptoms like characteristic acute diarrhea and weight loss of colitis. This study suggested that colostrums from sheep immunized against TNF-${\alpha}$ significantly inhibited TNF-${\alpha}$ bioactivity in the cell based assay. And the higher than anticipated variability in the two animal models precluded assessment of the ability of antibody to prevent TNF-${\alpha}$ induced intestinal damage in the intact animal. Further study will require to find out an alternative animal model, which is more acceptable to test anti-TNF-${\alpha}$ IgA therapy for reducing the impact of inflammation on gut dysfunction. And subsequent pre-clinical and clinical testing also need generation of more antibody as current supplies are low.

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Studies on a Factor Affecting Composts Maturity During Composting of SWine Manure (돈분 퇴비화 중 부숙도에 미치는 영향인자 구명)

  • Kim, T.I.;Song, J. I.;Yang, C.B.;Kim, M.K.
    • Journal of Animal Science and Technology
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    • v.46 no.2
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    • pp.261-272
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    • 2004
  • This study was conducted to investigate indices affecting composts maturity for swine manure compost produced in a commercial composting facility with air-forced from the bottom. The composting was made of swine manure mixed with puffing rice hull(6: 4) and turned by escalating agitator twice a day. Composting samples were collected periodically during a 45-d composting cycle at that system, showing that indices of Ammonium-N to Nitrate-N ratio were sensitive indicators of composting quality. Pile temperature maintained more than 62$^{\circ}C$ and water contents decreased about 20% for 25days of composting. A great variety and high numbers of aerobic thermophilic heterotropic microbes playing critical roles in stability of composts have been examined in the final composts, sbowing that they were detected $10^8$ to $10^{10}$ $CFUg^{-1}$ in mesophilic bacteria, $10^3$ - $10^4$ in fungi and $10^6$ - $10^8$ in actinomycetes, respectively. The results of this study for detennining a factor affecting compost stability evaluations based on composting steps were as follows; 1. Ammonium-N concentrations were highest at the beginning of composting, reaching approximately 421mg/kg. However Ammonium-N concentrations were lower during curing, reaching approximately l04mg/kg just after 45 day. The ratio between $NH_4-N$ and $NO_3-N$ was above II at the beginning of composting and less than 2 at the final step(45 day). 2. Seed germination Index was dependent upon the compost phytotoxicity and its nutrition. The phytotocity caused the GI to low during the period of active composting(till 25 days of composting time) depending on the value of the undiluted. After 25 days of composting time, the GI was dependent upon compost nutrition. The Gennination index of the final step was calculated at over 80 without regard to treatments. 3. E4: E6 ratio in humic acid of composts was correlatively decreased from 8.86 to 6.76 during the period of active composting. After 25 days of composting time, the E4: E6 was consistently decreased from 6.76 to 4.67($r^2$ of total composting period was 0.95). 4. Water soluble carbon had a tendency to increase from 0.54% to 0.78%during the period of active composting. After 25 days of composting time, it was consistently decreased from 0.78% to 0.42%. Water soluble nitrogen increased from 0.22% to 0.32% during the period of 15 days after initial composting while decreased from 0.32% to 0.21% after 15days of composting. In consequence, the correlation coefficient($r^2$) between water soluble carbon and water soluble nitrogen was 0.12 during the period of active composting mule was 0.50 after 25 days of composting time

Clinical significance of loss of p16 protein by immunohistochemical staining in acute lymphoblastic leukemia (급성림프구성백혈병에서 면역조직화학염색에 의한 p16 단백질 소실의 의의)

  • Jin, Hye Young;Kang, Kyoung In;Kim, Sun Young;Youn, You Sook;Kang, Joon Won;Jo, Deog Yeon;Kwon, Kye Chul;Park, Kyung Duk
    • Clinical and Experimental Pediatrics
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    • v.51 no.1
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    • pp.73-77
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    • 2008
  • Purpose : p16 gene, mapped to the 9p21 chromosomal region, has emerged as a candidate tumor suppressor gene in human neoplasm. It is an inhibitor of cyclin-dependent kinase and inhibits Rb phosphorylation. In a variety of tumors including childhood acute lymphoblastic leukemia (ALL), deletion and/or mutation of the p16 gene has been found. Despite their high frequency, the prognostic importance of p16 alterations is still controversial in ALL and has been reported to be either unfavorable or similar to that of other patients. We studied the correlation between loss of p16 protein confirmed by immunohistochemical staining and clinical outcomes of patients diagnosed as ALL. Methods : We performed an immunohistochemical staining for p16 protein in 74 cases of bone marrow biopsy slide initially diagnosed as ALL between January 1998 and December 2006. We reviewed the clinical manifestations, laboratory findings, treatment outcomes retrospectively. Results : Of 74 slides, 12 were negative for p16 protein. Seven were males and 5 were females with a median age at diagnosis was 5.8 (1.3-18.8) years. Initial WBC were 17,225 $(500-403,300)/{\mu}L$. By immunologic surface marker analysis, 7 patients were early pre-B CALLA (+) and 5 patients were T-cell ALL. Two patients of intermediate risk group had relapsed and died. Three patients had family history of breast cancer. Four patients died and overall survival rates were $53.5{\pm}18.7%$. Conclusion : Loss of p16 protein is supposed to be an independent risk factor of childhood ALL associated with poor outcomes. In clinical setting, the clinician must take into account p16 status, not only at the genomic but also at the protein level. Further clinical experience on thoroughly investigated cases will help a better understanding between p16 status and clinical outcomes.

Long term prognosis of patients who had a Fontan operation (폰탄 수술을 받은 환아들의 장기적 예후)

  • Kim, Hyun-Jung;Bae, Eun-Jung;Noh, Jung-Il;Choi, Jung-Yun;Yun, Yong-Su;Kim, Wong-Hwan;Lee, Jung-Yeul;Kim, Yong-Jin
    • Clinical and Experimental Pediatrics
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    • v.50 no.1
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    • pp.40-46
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    • 2007
  • Purpose : This study assessed the long term survival rate and long term complications of patients who had a modified Fontan operation for functionally univentricular cardiac anomaly. Methods : Between June 1986 and December 2000, 302 patients with a functional single ventricle underwent surgical interventions and were followed up until February 2006. The mean follow-up period was $8.3{\pm}5.3years$ (range 3.5-18 years). Their median age was 2.4 years at the Fontan operation. The survival rate, the incidence and the risk factor of late complications were evaluated retrospectively. Results : The verall survival rate was 91 percent at 5 years and 87 percent at 10 years. In multivariate analysis, early calendar year of operation and significant regurgitation were risk factors of death. The surviving patients showed NYHA functional class I in 82 percent, class II in 15 percent, and class III in 3 percent. Redo Fontan operations were necessary in 8.8 percent of patients at average $12.8{\pm}3.6years$ after initial Fontan operation. The most common cause of Fontan conversion was atrial arrhythmia. The incidence of thromboembolic events was 9.3% and these complications were associated with the occurrence of atrial tachyarrhythmia. Supraventricular tachycardia including atrial flutter or fibrillation were reported on the follow-up examination by 11.2 percent of survivors after $8.4{\pm}5.6years$. Atriopulmonary connection showed higher rates of late tachycardia than lateral tunnel operation. Conclusions : This study revealed that the recent survival rate of Fontan type operation was satisfactory, but the occurrence of late complications after a Fontan type operation increased with the longer survival. There is a need for strict follow up and early treatment of late complications in patients who had a Fontan operation.

Applying QFD in the Development of Sensible Brassiere for Middle Aged Women (QFD(품질 기능 전개도)를 이용한 중년 여성의 감성 Brassiere 개발)

  • Kim Jeong-hwa;Hong Kyung-hi;Scheurell Diane M.
    • Journal of the Korean Society of Clothing and Textiles
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    • v.28 no.12 s.138
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    • pp.1596-1604
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    • 2004
  • Quality Function Deployment(QFD) is a product development tool which ensures that the voice of the customer needs is heard and translated into products. To develop a sensible brassiere for middle-aged women QFD was adopted. In this study the applicability and usefulness of QFD was examined through the engineering design process for a sensible brassiere for middle-aged women. The customer needs for the wear comfort of brassiere was made by one-on-one survey of 100 women who aged 30-40. The customer competitive assessment was generated by wearing tests of 10 commercial brassieres. The subjective assessment was conducted in the enviornmental chamber that was controlled at $28{\pm}1^{\circ}C,\;65{\pm}3\%RH.$ As a results, we developed twenty-one customer needs and corresponding HOWs for the wear comfort of brassiere. The Customer Competitive Assessment was generated by wearing tests of commercial brassiere. The subjective measurement scale and dimension for the evaluation of sensible brassiere were extracted from factor analysis. Four factors were fitting, aesthetic property, pressure sensation, displacement of brassiere due to movement. The most critical design parameter was wire-related property and second one was stretchability of main material of brassiere. Also, wearing comfort of brassiere was affected by the interaction of initial stretchability of wing and support of strap. Engineering design process, QFD was applicable to the development of technical and aesthetic brassieres.

Inhibition of Quorum Sensing and Biofilm Formation by Synthetic Quorum Signal Analogues in Pseudomonas aeruginosa (합성된 쿼럼 신호 유사 물질에 의한 녹농균 쿼럼 센싱 및 생물막 형성의 제어)

  • Kim, Soo-Kyoung;Kim, Cheol-Jin;Yoon, Je-Yong;Lee, Joon-Hee
    • Microbiology and Biotechnology Letters
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    • v.39 no.1
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    • pp.29-36
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    • 2011
  • Pseudomonas aeruginosa is an opportunistic pathogen that causes various infections on urinary track, cornea, respiratory track, and burn wound site, and mainly relies on quorum sensing (QS) for its virulence. To control the infectivity of P. aeruginosa, we previously synthesized the structural analogues of a major QS signal, N-3-oxododecanoyl homoserine lactone (3OC12-HSL) to use as a QS inhibitor. Two of them (5b and 5f) had been confirmed to have an inhibitory effect on LasR, a major QS signal receptor of P. aeruginosa in the screening by the recombinant Escherichia coli reporter. To further evaluate these compounds, we tested their efficacy to control the QS and virulence of P. aeruginosa. Unlike the result from E. coli reporter, both 5b and 5f failed to affect the LasR activity in P. aeruginosa, but instead they selectively affected the activity of QscR, another 3OC12-HSL receptor of P. aeruginosa. Interestingly, their effect on QscR was complex and opposite to what we obtained with E. coli system. Both 5b and 5f enhanced the QscR activity at the low concentration range (< 10 ${\mu}m$), but high concentration of 5f (${\approx}$1 mM) strongly inhibited QscR. While 5b and 5f didn't affect the production of proteases, the key virulence factor, they significantly reduced the biofilm formation that is important in mediating chronic infections. Especially, 5f inhibited the initial attachment of P. aeruginosa, rather than the biofilm maturation. Based on our results, we suggest that 5f can be applied for an anti-biofilm agent without increasing virulence of P. aeruginosa.

Rapid Statistical Optimization of Cultural Conditions for Mass Production of Carboxymethylcellulase by a Newly Isolated Marine Bacterium, Bacillus velezensis A-68 from Rice Hulls (통계학적 방법을 사용한 해양미생물 Bacillus velezensis A-68균주의 섬유소 분해효소 생산 조건 최적화)

  • Kim, Bo-Kyung;Kim, Hye-Jin;Lee, Jin-Woo
    • Journal of Life Science
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    • v.23 no.6
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    • pp.757-769
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    • 2013
  • A microorganism producing carboxymethylcellulase (CMCase) was isolated from seawater, identified as Bacillus velezensis by analyses of 16S rDNA and partial sequences of the gyrA, and designated as B. velezensis A-68. The optimal conditions for production of CMCase by B. velezensis A-68 were established using response surface methodology (RSM). The optimal concentrations of rice hulls and yeast extract, and initial pH of the medium for cell growth were 60.2 g/l, 7.38 g/l, and 7.18, respectively, whereas those for production of CMCase were 50.0 g/l, 5.00 g/l, and 7.30. The analysis of variance (ANOVA) implied that the most significant factor for cell growth as well as production of CMCase was yeast extract. The optimal concentrations of $K_2HPO_4$, NaCl, $MgSO_4{\cdot}7H_2O$, and $(NH_4)_2SO_4$ in the medium for cell growth were 7.50, 1.00, 0.10, and 0.80 g/l, respectively, which were the same as those for production of CMCase. The optimal temperatures for cell growth and production of CMCase were 30 and $35^{\circ}C$, respectively. The maximal production of CMCase under optimized conditions was 83.8 U/ml, which was 3.3 times higher than that before optimization. In this study, rice hulls, agro-byproduct, were developed as a substrate for production of CMCase and time for production of CMCase was reduced to 3 days using a newly isolated marine bacterium.