• 제목/요약/키워드: Adjusting p-value

검색결과 83건 처리시간 0.031초

간세포암종의 재발 위험과 관련된 한 예후인자로서의 종양의 크기의 범주화 (Categorizing tumor size as a prognostic factor for risk of relapse of hepatocellular carcinoma)

  • 김선우;박철근
    • 응용통계연구
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    • 제15권1호
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    • pp.1-8
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    • 2002
  • 예후인자의 범주화는 질병의 진단, 치료법 결정 및 임상시험의 참여기준 설정 등에 매우 유용하다. 예후인자의 범주화 방법으로는 생물학적 이론에 따라 경계값을 정하는 방법, 자료의 그래프를 이용하는 방법, 모든 가능한 경계 값들을 적용해보는 최소 유의확률 방법 등이 있다. 또한 최소 유의확률 방법의 다중검정문제를 보완한 몇 가지 방법들이 있다. 본 연구에서는 우리 나라에서 높은 발생률을 보이는 간세포암종의 절제술을 받은 환자들에 있어서 간 절제술 후 재발위험이 높은 군을 구별하는 한 근거로 종양의 크기를 범주화하기 위한 경계값을 결정하고자 하였다.

Electrostatic Properties of N-Acetyl-Cysteine-Coated Gold Surfaces Interacting with ZrO2 Surfaces

  • Park, Jin-Won
    • Bulletin of the Korean Chemical Society
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    • 제33권9호
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    • pp.2855-2860
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    • 2012
  • The coating N-acetyl cysteine (NAC) on gold surfaces may be used to design the distribution of either gold particle adsorbed to the $ZrO_2$ surface or vice versa by adjusting the electrostatic interactions. In this study, it was performed to find out electrostatic properties of the NAC-coated-gold surface and the $ZrO_2$ surface. The surface forces between the surfaces were measured as a function of the salt concentration and pH value using the AFM. By applying the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to the surface forces, the surface potential and charge density of the surfaces were quantitatively acquired for each salt concentration and each pH value. The dependence of the potential and charge density on the concentration was explained with the law of mass action, and the pH dependence was with the ionizable groups on the surface.

Electrostatic Properties of N-Acetyl-Cysteine-Coated Gold Surfaces Interacting with TiO2 Surfaces

  • Park, Jin-Won
    • Bulletin of the Korean Chemical Society
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    • 제30권4호
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    • pp.902-906
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    • 2009
  • It is found that that the coating N-acetyl cysteine (NAC) on gold surfaces may be used to design the distribution of either gold particle adsorbed to the $TiO_2$ surface or vice versa by adjusting the electrostatic interactions. In this study, we investigated electrostatic properties of the NAC-coated-gold surface and the $TiO_2$ surface. The surface forces between the surfaces were measured as a function of the salt concentration and pH value using the AFM. By applying the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to the surface forces, the surface potential and charge density of the surfaces were quantitatively acquired for each salt concentration and each pH value. The surface potential and charge density dependence on the salt concentration was explained with the law of mass action, and the pH dependence was with the ionizable groups on the surface.

성인 남성 근로자에서 비만 지표의 변화와 혈청지질치 변화와의 관련성 (The Relationship between Change in Obesity Indices and Change in Serum Lipids in Adult Male Workers)

  • 하영애;천병렬;감신;이성국;예민해
    • Journal of Preventive Medicine and Public Health
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    • 제29권3호
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    • pp.439-449
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    • 1996
  • 성인 남성 근로자들에 있어서 비만지표의 변화와 혈청지질치 변화와의 관련성을 평가하기 위하여, 대구시에 소재한 1개 회사의 남성 근로자 208명을 연구 대상자로 선정하였다. 1995년 7월에 신장, 체중, 허리둘레, 엉덩이둘레를 재고 혈압을 측정하였으며, 혈청 총 콜레스테롤, 중성지방, HDL-콜레스테롤 등을 검사하고 LDL-콜레스테롤, 심근경색지수를 계산하였다. 이를 1991년도에 검사된 기초 자료들과 비교하였다. 1. 4년간 체중이 1.63kg, 허리둘레가 3.61cm, 엉덩이둘레가 4.23cm, BMI가 $0.52kg/m^2$, Katsura 지수는 0.02만큼 유의하게 증가했지만, 허리 엉덩이둘레비는 0.021만큼 유의한 감소가 있었다(p<0.01). 총 콜레스테롤은 15.09mg/이, 중성지방 20.43mg/dl, HDL-콜레스테롤 9.40mg/dl, 그리고 심근경색지수는 2.87mg/dl 만큼 유의하게 증가하였다. (p<0.01). LDL-콜레스테롤은 3.50mg/dl 만큼 증가하였으나 유의하지는 않았다. 2. BMI 변화 및 Katsura 지수의 변화와 총 콜레스테롤의 변화(r=0.174, p<0.05), BMI 변화와 중성지방의 변화(r=0.374, p<0.01), 그리고 체중의 변화와 심근경색지수의 변화(r=-0.173, p<0.05)가 상대적으로 강한 상관성을 보였다. 허리 엉덩이둘레비 변화는 총 콜레스테롤 변화량과 양의 상관관계(r=0.162, p<0.05)를 보였지만 다른 혈청지질치들과는 유의한 관련성이 없었다. 3. 생활습관의 변화를 보정하고도 중성지방은 체중 (r=0.262, p<0.01), BMI(r=0.267, p<0.01) Katsura 지수(r=0.258, p<0.01)와 유의한 관련성이 있었다. 심근경색지수의 변화는 체중(r=-0.143, p<0.05), BMI(r=-0.158, p<0.05), Katsura 지수(r=-0.144, p<0.05)와 유의한 음의 관련성이 있었다. 이 중 BMI가 가장 큰 상관계수 값을 보였다. 4. 1991년의 허리 엉덩이둘레비로 분류한 경우, 상체형 비만군이 그렇지 않은 군에 비해 HDL-콜레스테롤과 심근경색지수의 증가폭이 유의하게 더 낮았다(p<0.05). Katsura 지수의 경우도 유사한 결과를 보였다. BMI로 분류한 경우에도 역시 비만군이 그렇지 않은 군에 비해 HDL-콜레스테롤, 심근경색지수 값들의 증가폭이 유의하게 낮았다(p<0.05 또는 p<0.01). 중성지방은 BMI로 분류한 경우 비만한 군의 증가폭이 유의하게 높았다(p<0.05). 이상의 결과로 보아, 성인 남성 근로자들에서 혈청 지질치 변화에 대한 비만도의 지표로는 BMI가 허리 엉덩이둘레비나 Katsura 지수보다 더 적절할 것으로 생각된다.

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The Study on the Electrical Characteristics of the Pulse Generator adopted Cascading Technique

  • Joung, Jong-Han;Kim, Moon-Hwan
    • Journal of Power Electronics
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    • 제4권2호
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    • pp.112-116
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    • 2004
  • The pulsed power systems have been widely used many other countries and their new applications have been developed by many researchers, such as E/P(Electrostatic Precipitator) to remove the industrial dust, DeNOx/DeSOx power systems, ozone generators and power sources of the laser beam, etc. In this paper, we studied the cascading technique as a new technology consisted of two pulse transformers and obtained their experimental data and results. To obtain the high pulsed voltage adopted cascading technique, we designed our compact pulse generator and tested by adjusting the value of the load resistors to obtain high pulsed voltage with steep rising time and duration time. We explained their experimental results that obtained by adopting cascading technique. Also, we compared theoretical value with measured value obtained by using the cascading method.

Low Serum Potassium Levels Associated with Disease Severity in Children with Nonalcoholic Fatty Liver Disease

  • Tabbaa, Adam;Shaker, Mina;Lopez, Rocio;Hoshemand, Kazem;Nobili, Valerio;Alkhouri, Naim
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • 제18권3호
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    • pp.168-174
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    • 2015
  • Purpose: Recent studies have suggested that decreased serum potassium level may contribute to various metabolic disorders in adult patients including nonalcoholic fatty liver disease (NAFLD). We aimed to study the correlation between serum potassium levels and the histologic severity of NAFLD in children. Methods: Pediatric patients with biopsy-proven NAFLD were included in this study. Demographic, clinical, and histopathological data were obtained. Multivariable logistic regression analysis was used to assess whether potassium levels are associated with the presence of nonalcoholic steatohepatitis (NASH) or fibrosis after adjusting for possible confounders. A p-value <0.05 was considered statistically significant. Results: Among 125 biopsies, 49.6% (62) had evidence of NASH while 66.4% (83) had some degree of fibrosis (stage 1-3). Mean serum potassium was significantly lower in NASH group as compared to non-NASH group ($4.4{\pm}0.42mmoL/L$ vs. $4.8{\pm}0.21$, p<0.001). Higher potassium level had negative correlation with presence of steatosis, ballooning, lobular inflammation, fibrosis and NAFLD activity score (p<0.05). On multivariable analysis and after adjusting for the metabolic syndrome and insulin resistance, higher potassium level was significantly associated with lower likelihood of having a histological diagnosis of NASH on biopsy (odds ratio [OR], 0.12; 95% confidence interval [95% CI], 0.05-0.28; p<0.001). Similarly, the likelihood of having fibrosis decreases by 76% for every 0.5 mmoL/L increase in potassium (OR, 0.24; 95% CI, 0.11-0.54; p<0.001). Conclusion: Our study shows an inverse relationship between serum potassium levels and the presence of aggressive disease (NASH and fibrosis) in children with NAFLD.

두경부암 방사선 치료 시 Set-Up 조정 Head Holder 장치의 개발 (Development of Adjustable Head holder Couch in H&N Cancer Radiation Therapy)

  • 심재구;송기원;김진만;박명환
    • 대한방사선치료학회지
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    • 제26권1호
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    • pp.43-50
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    • 2014
  • 두경부암 환자의 헤드 홀더를 사용하는 경우 모의 치료 시 환자는 테이블 위에 위치하지만, 방사선 치료를 시행하는 경우 헤드 홀더를 치료 테이블에 걸쳐서 사용하기 때문에 체중 및 여러 가지 요소로 인한 기하학적 불일치로 상, 하, 좌, 우 및 처짐의 현상이 발생할 수 있다. 이러한 환자 Set-Up의 재현성의 불일치를 개선하기 위해 두경부암 전용 헤드 홀더를 자체 고안하여 제작 및 개발하여 유용성을 평가하였다. Alderson Rando Phantom을 이용하여 전산화단층촬영장치(High Advantage, GE, U.S.A)를 통해 이미지를 획득하였고, 광자선 4MV 세기변조 방사선치료(IMRT) 방식을 적용하여 최적화된 치료 계획을 실시하였다. 선형가속기(21EX, Varian, U.S.A)를 이용하여 모의 치료와 동일한 상태에서 환자를 set-up한 후 에 치료기에 장착된 CBCT를 이용하여 각각의 무게(0,15,30Kg)의 차이를 통해 교정 전, 후 X, Y, Z축의 오차를 5회 반복 측정한 결과는 다음과 같다. 0Kg에서 $0.4{\pm}0.8mm$, $0.8{\pm}0.4mm$, 0mm으로 나타났고, 교정 후에는 $0.2{\pm}0.8mm$, $0.4{\pm}0.5mm$, 0으로 나타났다. 15Kg에서 교정 전,후 오차는 $0.2{\pm}0.8mm$, $1.2{\pm}0.4mm$, $2.2{\pm}0.4mm$$0.2{\pm}0.4mm$, $0.4{\pm}0.5mm$, $0.4{\pm}0.5mm$로 나타났다. 30Kg에서 교정 전,후 오차는 $0.8{\pm}0.4mm$, $2.4{\pm}0.5mm$, $4.4{\pm}0.8mm$$0.6{\pm}0.54mm$, $1{\pm}0mm$, $0.6{\pm}0.5mm$로 나타났다. 각각의 교정 전,후의 통계적으로 분석한 결과 15Kg인 경우 Z축에서 p<0.034, 30Kg인 경우 Y, Z축에서 p<0.038, p<0.041 로 유의한 결과를 나타냈다. 두경부암 전용 방향 조절 장치 헤드 홀더가 환자의 set-up오차를 줄여주는 역할을 해주는 것으로 나타났다. 또한 오차를 줄여줌으로써 환자의 재현성이 향상되어 보다 정밀하고 정확한 방사선 치료를 구현할 수 있을 것으로 사료된다.

성별, 연령별, 월소득차이에 따른 질병발생의 위험성 차이연구;암, 고혈압, 중풍, 당뇨병, 관절염, 심장병을 중심으로 (The Risk of Onset of the Illnesses Based on Gender, Age, and Monthly Income;Focusing on cancer, hypertension, stroke, diabetes, arthritis, cardiac disorders)

  • 이준오;김세진;이선동
    • 대한예방한의학회지
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    • 제12권1호
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    • pp.19-48
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    • 2008
  • In order to verify the risk of onset of the illnesses based on gender, age, and monthly income 1,739 subjects from Hongcheon county, Gangwon province were selected. Questionnaire on demographic sociology, health condition, existence of illnesses(cancer, hypertension, stroke, diabetes, arthritis, cardiac disorders), and usage of public health services was surveyed from October 1, 2006 to October 20, 2006. Following conclusions were reached on the basis of the questionnaire : - For demographic sociological peculiarities, gender, age, occupation, and education level were evenly distributed. Most were under normal marriage(67.38%), health insurance(86.39%), 494(36.0%) individuals with less than monthly income of 1 million won, 494(36.0%) individuals with monthly income between 1 and 2 million won, 219(16.0%) with monthly income between 2 and 3 million won, and 164(12.0%) individuals with more than 3 million won, thus showing relatively low income. - For health status, 1,199(70.28%) individuals are non-smokers, 209(45.63%) individuals smoke $10{\sim}20$ cigarettes a day, 754(44.02%) individuals exercise less than twice a week are the major sector of the population. 1,518(88.10%) individuals have regular checkup more than once and 1,131(65.49%) stated their health condition less than average. - For comparison of existence of illnesses between genders, there was no statistical significance on cancer, stroke, and diabetes. But statistical significance was shown on hypertension(P value 0.025), arthritis(P value 0.000), and cardiac disorders(P value 0.016). Statistical significance was seen in the age comparison, and OR(confidence interval) drastically increased with increase in age. - There was no difference between the primary health clinic(P value 0.000), most visited clinic(P value 0.000), selection criteria(P value 0.000), and satisfaction on efficacy(P value 0.000). There was a tendency preferring hospital than public health center with increase in income. - For correlation between the existence of illnesses among different income levels, except for cancer(P value 0.172), statistical significance was seen in hypertension(P value 0.000), stroke(P value 0.003), diabetes (P value 0.001), arthritis(P value 0.000), and cardiac disorders(P value 0.000). The number of individuals suffering from illnesses and ratio all decreased for all illnesses with increase in income. - After adjusting confounding factors(gender, age, income, marriage, occupation, education) and male (1) as the standard, OR (confidence interval) of cancer, hypertension, stroke, diabetes, arthritis, cardiac disorders were 0.47(0.11${\sim}$2.05), 1.27(0.89${\sim}$1.81), 0.58(0.21${\sim}$1.59), 0.71(0.41${\sim}$1.23), 1.79(1.34${\sim}$2.39, P<0.01), and 1.46(0.72${\sim}$2.96), respectively. Risk of arthritis is significantly high in female and 20's (1) as the standard, OR(confidence interval) of cancer, hypertension, stroke, diabetes, arthritis, cardiac disorders were 1.01(0.96${\sim}$1.07), 1.06(1.04${\sim}$1.07, P<0.01), 1.05(1.01${\sim}$1.10, P<0.01), 1.06(1.03${\sim}$1.08, P<0.01), 1.05(1.03${\sim}$1.06, P<0.01), and 1.06(1.04${\sim}$1.09, P<0.01), respectively. Risk of onset for illnesses significantly increased with yearly aging except for cancer. - For comparison between monthly income after adjusting confounding factors(gender, age, income, marriage, occupation, education), with less than 1 million won (1) as the standard, OR(confidence interval) of cancer for 1 to 2 million won, 2 to 3 million won, and more than 3 million won were 0.23(0.03${\sim}$2.16), 2.53(0.41${\sim}$15.43), and 1.73(0.15${\sim}$19.50), respectively. OR(confidence interval) of hypertension were 1.12(0.76 ${\sim}$1.66), 0.68(0.34${\sim}$1.34), and 2.04(1.08${\sim}$3.86, P<0.01), respectively. OR(confidence interval) of stroke were 0.96(0.30${\sim}$3.08) for 1 to 2 million won, and 0.80(0.08${\sim}$8.46) for 2 to 3 million won. OR(confidence interval) of diabetes were 0.73(0.38${\sim}$1.38), 0.65(0.24${\sim}$1.71), and 0.69(0.24${\sim}$2.01), respectively. The values were 0.76(0.55${\sim}$1.03), 1.14(0.75${\sim}$1.73), and 0.90(0.56${\sim}$1.46), respectively for arthritis. OR(confidence interval) of cardiac disorders were 1.15(0.53${\sim}$2.48), 0.63(0.13${\sim}$3.12), and 1.20(0.28${\sim}$5.14), respectively. Risks of cancer, hypertension, stroke, diabetes, arthritis, and cardiac disorders were dependent of monthly income, and stroke and diabetes decreased with increase in income. Summarizing above data, arthritis was significantly higher in women and increase in age by each year brought significant increase in the chance of onset in hypertension, stroke, diabetes, arthritis, and cardiac disorders except for cancer. Stroke and diabetes decreased with increase in income. Above findings can be applied and reflected in public health policies at the national level, and it can also be applied at the personal level for individual health maintenance and prevention.

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A study on boron removal for seawater desalination using the combination process of mineral cluster and RO membrane system

  • Cho, Bong-Yeon;Kim, Hye-Won;Shin, Yee-Sook
    • Environmental Engineering Research
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    • 제20권3호
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    • pp.285-289
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    • 2015
  • Complicated and expensive seawater desalination technology is a big challenge in boron removal process. Conventional seawater desalination process of coagulation utilized for pre-treatment is difficult to remove boron. Boron can be removed more effectively in Reverse Osmosis (RO) process than any other processes. In this study, a coagulant with the name Mineral Cluster was examined its boron removal ability. Boron removal efficiency of Mineral Cluster depended on pH value and Mineral Cluster dosage. Desalination process combines the pre-treatment process with Mineral cluster diluted at the ratio of 1:2500 and the RO membrane process. The original sea water could be desalinated to drinking water quality, 1 mg/L, without any pH adjustments. Therefore, if the Mineral cluster is added without any other chemicals for adjusting pH, the desalination process would be much safer, efficient and economical.

매몰채널 pMOSFET소자의 서브쓰레쉬홀드 특성 고찰 (Subthreshold characteristics of buried-channel pMOSFET device)

  • 서용진;장의구
    • E2M - 전기 전자와 첨단 소재
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    • 제8권6호
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    • pp.708-714
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    • 1995
  • We have discussed the buried-channel(BC) behavior through the subthreshold characteristics of submicron PMOSFET device fabricated with twin well CMOS process. In this paper, we have guessed the initial conditions of ion implantation using process simulation, obtained the subthreshold characteristics as a function of process parameter variation such as threshold adjusting ion implant dose($D_c$), channel length(L), gate oxide thickness($T_ox$) and junction depth of source/drain($X_j$) using device simulation. The buried channel behavior with these process prarameter variation were showed apparent difference. Also, the fabricated pMOSFET device having different channel length represented good S.S value and low leakage current with increasing drain voltage.

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