대장암 근치적 절제술후 재발양상에 관한 임상적 연구

이길연,홍성화,고석환,윤충,고영관,이기형,박주철 대한대장항문학회 1996 Annals of Coloproctolgy Vol.12 No.2

산업장 소음에 노출된 근로자들의 활동 중 혈압과 심박동수

김영기,차태준,변주현,고광욱,이용환 大韓産業醫學會 2000 대한직업환경의학회지 Vol.12 No.1

목적 : 산업장 근무 근로자들에 있어서 소음 노출이 혈압과 심박동수에 미치는 영향을 조사하고자 하였다. 방법 : 부산시 소재 한 주물공장 근무 근로자로서 소음 작업장에 근무하는 102명에 대하여 1998년 3-6월, 1999년 3-6월에 걸쳐 안정시 혈압과 청력손실정도, 일반적 특성이 조사되었다. 소음노출 정도는 noise dosimeter를 사용하여 오전 8시-오후 4시까지 8시간동안 측정하여 평가하였고, 활동 중 혈압과 심박동수는 ambulatory blood pressure로 오전 8 시-오후 10시까지 30분 단위로 측정하였다. 결과 : 연령과 흡연, 신체비만지수의 영향을 고려하였을 때 저연령층에서 85dBA이상의 고소음에 노출된 군에서 소음과 수축기 혈압간에는 유의한 양의 상관관계가 있었으나, 이완기 혈압과 심박등수에서는 유의한 결과를 얻지 못하였다. 연령의 구분없이 상관관계를 구하였을 때에는 수축기 혈압에서만 소음수준과 유의한 상관성이 있었다. 오전 8시-오후 10시까지 측정한 활동 중 혈압과 심박동수의 일일 변화는 40세미만의 저연령층에서는 심박동수에서만 근무후의 오후시간부터 감소하는 양상이 있었고 수축기 혈압과 이완기 혈압에서는 뚜렷한 변화를 발견할 수 없었다. 40세이상군에서는 수축기혈압과 이완기 혈압, 심박동수 모두 근무 중에는 비교적 높은 값을 유지하다가 오후부터는 감소하는 추세를 보이고 있었다. 각 연령군별 소음노출수준에 따른 활동 중 혈압과 심박동수의 비교에서는 40세미만의 연령층에서만 85dBA이상의 고소음군에서 심박동수가 유의하게 더 높은 결과를 얻었다. 결론 : 저연령층인 40세피만에서 85dBA이상의 고소음에 지속적으로 노출될 경우 수축기 혈압이 증가되어 있을 수 있음을 확인하였다. Objectives : This study was carriel out to evaluate the effects of Industrial noise on blood pressure and heart rate. Methods Resting blood pressure, hearing loss, and general characteristics of the 102 subjects who were engaged In a factory in Pusan were measured from March to June for two years, in 1998 and 1999. With noise dosimeter, noise exposure level was measured from 8 A.M. to 4 P.M. Ambulatory blood pressure and heart rate were also measured every 30 minutes from 8 A. M. to 10 p. M. Results : Controlling for age, smoking, and Quetelet's index, in subjects of under 40 years old exposed to higher than 85dBA, noise exposure and systolic blood pressure had astatistically significant correlation, and the same result was obtained in all subjects. The daily variability of ambulatory blood pressure and heart rate were observed in older than 40 years old group, but only heal·t rate in under 40 years old. Conclusions : The blood pressure and heart 1·ate would be elevated when the workers exposed to noise. And in under 40 years old, the systolic blood pressure was elevated to the workers exposed to higher than 85dBA.

DDC,MEA,WR-2721의 放射線 防護效果에 關한 硏究

柳星烈,陳秀一,鄭鉉佑,鄭引溶,高柱煥,고경환 대한방사선 방어학회 1986 방사선방어학회지 Vol.11 No.2

放射線障害 豫防藥劑의 人體適用은 副作用으로 臨床的 利用이 되지 못한 實情으로서 生理學的 및 藥理學的 毒性, 物理學的 諸性質, 藥劑의 作用機轉究明 및 臨床的 技術開發이 未洽하여 放射線 障害者에 對한 治療는 對症療法에 不過한 實情이다. 著者들은 放射線에 依한 人體障害豫防에 必要한 基礎資料를 얻기 위하여 現在까지 比較的 毒性이 적고 化學的으로 安定하며 藥效가 優秀하다고 알려진 DDC, MEA, WR-2721을 選定하여 實驗動物 非近交系 Swiss Webster(NIH-GP)마우스에 利用한 放射線 防護作用에 關한 實驗結果는 다음과 같다. 1) 各種 放射線 防護劑(DDC, MEA, WR-2721)의 마우스에 대한 適定 投與量은 各各 DDC; 1,000, MEA; 200, WR-2721; 400mg/kg이었다. 2) 實驗動物에 放射線 反致死線量 LD50/10에 對한 藥劑의 防護效果을SMS DDC;1.2, MEA; 1.4, WR-2721; 1.9이었고 LD50/30에 對 한 DMF는 DDC; 1.7, MEA; 1.8, WR-2721; 2.5이었다. 3) 空腹 小?腺(Jejunum crypt)의 放射線平均致死線量(Do)에 對한 防護效果 DMF는 DCC; 1.07, MEA; 1.21, WR-2721; 1.76이었고, 小?腺細胞의 致死線 平均致死線量에 對한 DMF는 DDC; 1.04, MEA; 1.08, WR-2721; 1.38이었다. 4) 以上으로 上記 3種의 放射線 防護劑中 WR-2721의 放射線 防護效果가 가장 優秀하였고 이 結果는 向後 臨床的 適用에 關한 硏究의 基礎資料가 될 것으로 思料된다. At present, the treatments of the radiation-induced diseases are only performing by the palliative treatment technique. Moreover, radiation protective agents are a little toxic for human being and this seriously limits their applicability with various complications in clinical uses. Accordingly, as a part of the aim of gain of the basic data for protective roles of some radioprotectors, the present investingation was carried out to evaluate the comparative radioprotective effects by the administration of DDC, MEA, WR-2721. Results are shown for statistically significant analysis and correlation with each group as follows; 1. The proper doses of the radioprotectors were DDC; 1,550mg/kg, MEA; 450mg/kg, WR-2721; 780mg/kg of the mouse body weight. 2. DMF(Dose modification factor) of LD50/10 and LD50/30 for whole body irradiation was DDC; 1.2, MEA; 1.4, WR-2721; 1.9 and DDC; 1.7, MEA; 1.8 and WR-2721; 2.5 respectively. 3. DMF for radiation reaction of jejunal crypt was DDC; 1.07, MEA; 1.21 and WR-2721; 1.76 and that of jejunal crypt cell was DDC; 1.04, MEA; 1.08 and WR-2721; 1.38 respectively. 4. Conclusively, WR-2721 was the most effective drung among the three radioprotectors and this result must be a supportive data for further study for clinical application.

Prediction of the glass transition temperature of semicrystalline polymer/salt complexes

Koh, Joo Hwan,Park, Jung Tae,Koh, Jong Kwan,Kim, Jong Hak Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of polymer science. Part B, Polymer physic Vol.47 No.8

<P>An explicit expression based on the configurational entropy model, the Flory-Huggins theory and Guggenheim's form of Debye-Hückel theory has been derived for predicting the glass transition temperatures (T<SUB>g</SUB>) of binary semicrystalline polymer/salt complexes. The proposed configurational entropy (S<SUB>c</SUB>) of polymer/salt systems consists of the disorientation entropy of polymer 1 (S<SUB>diso-1</SUB>), the dissociation entropy of salt (S<SUB>diss-2</SUB>), the mixing entropy (S<SUB>mix-12</SUB>) and the specific interaction entropy (S<SUB>spe-12</SUB>). In particular, the effect of crystalline segments was accounted for by the current model. The prediction of the proposed T<SUB>g</SUB> model is in good agreement with experimental data. Our results demonstrate that the small change of the T<SUB>g</SUB> in semicrystalline polymer/salt complexes compared to amorphous systems is mostly attributable to the reduced configurational entropy due to the presence of crystalline segments. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 793–798, 2009</P>

Fabrication of 3D interconnected porous TiO₂ nanotubes templated by poly(vinyl chloride-<i>g</i>-4-vinyl pyridine) for dye-sensitized solar cells

Koh, Joo Hwan,Koh, Jong Kwan,Seo, Jin Ah,Shin, Jong-Shik,Kim, Jong Hak IOP Pub 2011 Nanotechnology Vol.22 No.36

<P>Porous TiO<SUB>2</SUB> nanotube arrays with three-dimensional (3D) interconnectivity were prepared using a sol–gel process assisted by poly(vinyl chloride-<I>graft</I>-4-vinyl pyridine), PVC-<I>g</I>-P4VP graft copolymer and a ZnO nanorod template. A 7 µm long ZnO nanorod array was grown from the fluorine-doped tin oxide (FTO) glass via a liquid phase deposition method. The TiO<SUB>2</SUB> sol–gel solution templated by the PVC-<I>g</I>-P4VP graft copolymer produced a random 3D interconnection between the adjacent ZnO nanorods during spin coating. Upon etching of ZnO, TiO<SUB>2</SUB> nanotubes consisting of 10–15 nm nanoparticles were generated, as confirmed by wide-angle x-ray scattering (WAXS), energy-filtering transmission electron microscopy (EF-TEM) and field-emission scanning electron microscopy (FE-SEM). The ordered and interconnected nanotube architecture showed an enhanced light scattering effect and increased penetration of polymer electrolytes in dye-sensitized solar cells (DSSC). The energy conversion efficiency reached 1.82% for liquid electrolyte, and 1.46% for low molecular weight (<I>M</I><SUB>w</SUB>) and 0.74% for high <I>M</I><SUB>w</SUB> polymer electrolytes. </P>

Self-assembled structures of hydrogen-bonded poly(vinyl chloride-<i>g</i>-4-vinyl pyridine) graft copolymers

Koh, Joo Hwan,Seo, Jin Ah,Koh, Jong Kwan,Kim, Jong Hak IOP Pub 2010 Nanotechnology Vol.21 No.35

<P>An amphiphilic graft copolymer of poly(vinyl chloride-<I>graft</I>-4-vinyl pyridine), i.e., PVC-<I>g</I>-P4VP was synthesized via atom transfer radical polymerization (ATRP) and modified by introducing 1,5-dihydroxynaphthalene (DHN) as a hydrogen bonding donor to form hydrogen-bonded macromolecules. The PVC-<I>g</I>-P4VP graft copolymer prepared from a selective solvent for PVC, i.e., tetrahydrofuran (THF) exhibited a well-organized micellar morphology consisting of a P4VP core and a PVC corona. However, the graft copolymer prepared from a good solvent for both domains, i.e., <I>N</I>, <I>N</I>-dimethylformamide (DMF) showed a less-organized, random microphase-separated morphology. Upon the introduction of DHN, a more spherical morphology and a more-organized ‘bicontinuous-like’ morphology was observed in THF and DMF, respectively. This results from strong segregation between the two domains due to the enhanced interfacial energy by DHN. When DHN was removed by methanol, nanoporous films with versatile pore sizes and shapes were generated. </P>

Polystyrene-b-Poly(oxyethylene methacrylate) 블록 공중합체 막을 이용한 은 나노입자 생성

Joo Hwan Koh,Jin Ah Seo,Dong Kyu Roh,Jong Hak Kim 한국막학회 2010 멤브레인 Vol.20 No.1

원자전달 라디칼 중합을 이용하여 polystyrene-b-poly(oxyethylene methacrylate) (PS-b-POEM) 블록 공중합체를 합성하고, FT-IR을 통해 중합이 성공적으로 이루어졌음을 확인하였다. 또한 자기 조립된 블록 공중합체 막을 제조한 후, 전구체 AgCF3SO3 도입과 UV 조사를 통해 고체상에서 은 나노입자를 성장시켰다. TEM 전자현미경과 UV-visible 분광학 분석을 통해 블록 공중합체 막의 내부에 은 나노입자가 형성된 것을 확인하였고, 또한 친수성 POEM 영역의 함량을 조절함으로써 나노입자의 크기를 조절할 수 있었다. 금속 나노입자를 제조하는 데 있어서 POEM 함량이 적은 블록 공중합체가 더 효과적임을 확인하였다. A diblock copolymer of polystyrene-b-poly(oxyethylene methacrylate) (PS-b-POEM) was synthesized via atom transfer radical polymerization (ATRP), as revealed by FT-IR spectroscopy. The self-assembled block copolymer membrane was prepared and used to template the growth of silver nanoparticles in the solid state by the introduction of AgCF3SO3 precursor and UV irradiation process. Transmission electron microscopy (TEM) and UV-visible spectroscopy confirmed the in situ formation of silver nanoparticles within the block copolymer membranes, and the size of nanoparticles were controlled by adjusting the moiety of hydrophilic POEM domains. PS-b-POEM block copolymer with a lower POEM content was effective in generating smaller size of metal nanoparticles.

Templated synthesis of silver nanoparticles in amphiphilic poly(vinylidene fluoride-co-chlorotrifluoroethylene) comb copolymer

Koh, Joo Hwan,Kim, Yong Woo,Park, Jung Tae,Kim, Jong Hak Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of polymer science Part B, Polymer physics Vol.46 No.7

<P>In this study, poly(vinylidene fluoride-co-chlorotrifluoroethylene)-graft-poly(oxyethylene methacrylate), P(VDF-co-CTFE)-g-POEM, an amphiphilic comb copolymer with hydrophobic P(VDF-co-CTFE) backbone and hydrophilic POEM side chains at 73:27 wt % was synthesized. The POEM side chains were grafted from the P(VDF-co-CTFE) mainchain backbone via atom transfer radical polymerization (ATRP) using direct initiation of the chlorine atoms in CTFE units. Synthesis of microphase-separated P(VDF-co-CTFE)-g-POEM comb copolymer was successful, as confirmed by nuclear magnetic resonance (<SUP>1</SUP>H NMR), FTIR spectroscopy, and transmission electron microscopy (TEM). Nanocomposite films were prepared using the comb copolymer as a template film and the in situ reduction of AgCF<SUB>3</SUB>SO<SUB>3</SUB> precursor to silver nanoparticles under UV irradiation. Silver nanoparticles with 4–8 nm in average size were in situ created in the solid state template film, as revealed by TEM, UV–visible spectroscopy, and wide angle X-ray scattering (WAXS). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) presented the selective incorporation and the in situ growth of silver nanoparticles within the hydrophilic POEM domains of microphase-separated comb copolymer film. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 702–709, 2008</P>

Amphiphilic polymer electrolytes consisting of PVC-g-POEM comb-like copolymer and LiCF₃SO₃

Koh, Joo Hwan,Lee, Kyung Ju,Seo, Jin Ah,Kim, Jong Hak Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of polymer science. Part B, Polymer physic Vol.47 No.15

<P>An amphiphilic comb-like copolymer consisting of a poly(vinyl chloride) (PVC) backbone and poly((oxyethylene)<SUB>9</SUB> methacrylate) (POEM) side chains, PVC-graft-POEM was synthesized via atom transfer radical polymerization. This comb copolymer was complexed with LiCF<SUB>3</SUB>SO<SUB>3</SUB> to form a solid polymer electrolyte. FTIR and FT-Raman spectroscopy indicate that lithium salts are dissolved in the ion conducting POEM domains of microphase-separated graft copolymer up to 10 wt % of salt concentration. Microphase-separated structure of the materials and the selective interaction of lithium ions with POEM domains were revealed by transmission electron microscopy, wide angle X-ray scattering, and differential scanning calorimetry. The maximum ionic conductivity of 4.4 × 10<SUP>−5</SUP> S/cm at room temperature was achieved at 10 wt % of salt concentration, above which salts are present as less mobile species such as ion pairs and higher order ionic aggregates, as characterized by FT-Raman spectroscopy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1443–1451, 2009</P>

Preparation of nanoporous films from self-assembled poly(vinyl chloride-g-methyl methacrylate) graft copolymer

Joo Hwan Koh,김종학,Su Jin Byun,Won Seok Chi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.7

We report on the preparation of nanoporous films based on an amphiphilic graft copolymer of poly(vinyl chloride-graft-methyl methacrylate), i.e., PVC-g-PMMA. The PVC-g-PMMA graft copolymer was synthesized via atom transfer radical polymerization (ATRP), as confirmed by nuclear magnetic resonance spectroscopy (1H NMR),Fourier transform-infrared (FT-IR) spectroscopy, and gel permeation chromatography (GPC) analysis. The PVC-g-PMMA graft copolymer molecularly self-assembled into nanophase domains of PVC main chains and PMMA side chains, as revealed by wide angle X-ray scattering (WAXS) and transmission electron microscopy (TEM). The graft copolymer film prepared from tetrahydrofuran (THF), a good solvent for both chains, had a random microphase-separated morphology. However, when prepared from dimethyl sulfoxide (DMSO), a solvent selectively good for PVC,the film exhibited a micellar morphology consisting of a PMMA core and a PVC corona. Nanoporous films with different pore sizes and shapes were prepared through the selective etching of PMMA chains using a combined process of UV irradiation and acetic acid treatment.