Genotoxic Effects of the Cooked - Food - Related Mutagens IQ and Trp - p - 2 in Drosophila

Lee, Won Ho,Yoo, Mi Ae,Park, Tae Dong,Choo, Jong Kil 한국유전학회 1987 Genes & Genomics Vol.9 No.4

The heterocyclic amines, IQ and Trp-p-2 are the cooked-food-related carcinogens. To know genotoxic effects of IQ and Trp-p-2 in Drosophila, sensitivity to killing, somatic gene mutations and somatic chromosome mutations were measured in repair-deficient strain and repair-proficient strain after larval treatment. Gene mutations were detected with eye-color spot test system and chromosome mutations with wing spot test system. The relative potency of these two compounds in Drosophila will be discussed with the different response of mammalian system and Salmonella system.

Mechanically Robust, Stretchable Solar Absorbers with Submicron-Thick Multilayer Sheets for Wearable and Energy Applications

Lee, Hye Jin,Jung, Dae-Han,Kil, Tae-Hyeon,Kim, Sang Hyeon,Lee, Ki-Suk,Baek, Seung-Hyub,Choi, Won Jun,Baik, Jeong Min American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.21

<P>A facile method to fabricate a mechanically robust, stretchable solar absorber for stretchable heat generation and an enhanced thermoelectric generator (TEG) is demonstrated. This strategy is very simple: it uses a multilayer film made of titanium and magnesium fluoride optimized by a two-dimensional finite element frequency-domain simulation, followed by the application of mechanical stresses such as bending and stretching to the film. This process produces many microsized sheets with submicron thickness (similar to 500 nm), showing great adhesion to any substrates such as fabrics and polydimethylsiloxane. It exhibits a quite high light absorption of approximately 85% over a wavelength range of 0.2-4.0 mu m. Under 1 sun illumination, the solar absorber on various stretchable substrates increased the substrate temperature to approximately 60 degrees C, irrespective of various mechanical stresses such as bending, stretching, rubbing, and even washing. The TEG with the absorber on the top surface also showed an enhanced output power of 60%, compared with that without the absorber. With an incident solar radiation flux of 38.3 kW/m(2), the output power significantly increased to 24 mW/cm(2) because of the increase in the surface temperature to 141 degrees C.</P>

Endoscopy and Imaging Modalities/Basic Science of Gastrointestinal Disorders/Miscellaneous : The Usefulness Of CT Colonography As Postoperative Follow-Up Surveillance Study In Stomach Cancer Patients

( Won Seok Kang ),( Joon Seok Lim ),( Jae Hee Cheon ),( Yong Chan Lee ),( Won Ho Kim ),( Sang Kil Lee ) 대한소화기학회 2007 SIDDS Vol.9 No.-

Background/Aims: Stomach cancer is the most common from of cancer, and is the second leading cause of cancer related death in Korea. 3.4% of stomach cancer patients have synchronous of metachronous cancer with colorectal cancer as the most common type (0.6%). Patients with stomach cancer might carry a high risk for colorectal cancer that requires surveillance colonoscopy. CT colonography (CTC) provides for effective and relatively noninvasive risk stratification as a method for colon cancer screening. This study aims at determining the usefulness of CTC as a postoperative follow-up surveillance study after stomach cancer surgery. Methods: From May 2006 to April 2007, contrast-enhanced CTC was performed in Yonsei University severance Hospital for detection of recurrent lesions in 410 consecutive patients (275 male, 135 female) who have had surgery for stomach cancer CTC interpretation was performed with primary three-dimensional polyp detection. Patients with polyp(s) measuring 6mm or larger were referred for optical colonoscopy (OC). Results: Of 410 stomach cancer postoperative patients, recurrence of stomach cancer was not noted and 45 colorectal polyp(s) were detected on CTC in 36 (8.8%) patients. OC was recommended in these patients and concordant lesions were identified in 27 (60.0%) of 45 polyps. Eighty-six polyps were detected on OC in 31 patients, and no polyps were detected on OC in 5 patients. Four colorectal carcinomas were detected in 4 patients CTC. Sensitivity and positive predicitive value of CTC for polyp detection were 60.0% and 62.8%, respectively. Total 46 polyps were missed on CTC. The most common site of missed polyps was sigmoid colon. Eighteen (39.1%) were larger than 6 mm and 1 carcinoma was included in the missed polyps. Conclusion: For patients who have undergone surgical treatment for stomach cancer, CTC is clinically useful as their follow-up surveillance study. However, more efforts are needed to find the ways to improve the low sensitivity of CTC.

Modulation of Apoptosis and Differentiation by the Treatment of Sulfasalazine in Rabbit Articular Chondrocytes

Won Kil Lee,Jin Seok Kang 한국독성학회 2016 Toxicological Research Vol.32 No.2

This study was conducted to examine the cellular regulatory mechanisms of sulfasalazine (SSZ) in rabbit articular chondrocytes treated with sodium nitroprusside (SNP). Cell phenotype was determined, and the MTT assay, Western blot analysis and immunofluorescence staining of type II collagen was performed in control, SNP-treated and SNP plus SSZ (50~200 μg/mL) rabbit articular chondrocytes. Cellular proliferation was decreased significantly in the SNP-treated group compared with that in the control (p < 0.01). SSZ treatment clearly increased the SNP-reduced proliferation levels in a concentration-dependent manner (p < 0.01). SNP treatment induced significant dedifferentiation and inflammation compared with control chondrocytes (p < 0.01). Type II collagen expression levels increased in a concentration-dependent manner in response to SSZ treatment but were unaltered in SNP-treated chondrocytes (p < 0.05 and < 0.01, respectively). Cylooxygenase-2 (COX-2) expression increased in a concentration-dependent manner in response to SSZ treatment but was unaltered in SNP-treated chondrocytes (p < 0.05). Immunofluorescence staining showed that SSZ treatment increased type II collagen expression compared with that in SNP-treated chondrocytes. Furthermore, phosphorylated extracellular regulated kinase (pERK) expression levels were decreased significantly in the SNP-treated group compared with those in control chondrocytes (p < 0.01). Expression levels of pERK increased in a concentration-dependent manner by SSZ but were unaltered in SNP-treated chondrocytes. pp38 kinase expression levels increased in a concentrationdependent manner by SSZ but were unaltered in control chondrocytes (p < 0.01). In summary, SSZ significantly inhibited nitric oxide-induced cell death and dedifferentiation, and regulated extracellular regulated kinases 1 and 2 and p38 kinase in rabbit articular chondrocytes.

Effect of Substrate Temperature on the Electrochromic Properties and Cyclic Durability of Nickel Oxide Film

Kil Dong Lee,Won Chae Jung 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.2

Electrochromic NiO lms were prepared by using an electron-beam deposition method. The in uence of the preparation conditions, especially the substrate temperature, on the cyclic durability and the properties of the lms were investigated. The optical properties and the cyclic durability of as-deposited lms strongly depended on the substrate temperature during deposition. The NiO lms deposited with substrate temperatures of 150 200 C showed excellent electrochromism and stable durability characteristics after 5000 cycles. The charge left in the lms for these samples was a minimum. The best electrochromic parameters after 5000 cycles were obtained for samples prepared with a substrate temperature of 150 C. The obtained electrochromic parameters were

Poster Session : PS 1047 ; Gastroenterology (Gastrointestinal Tract) ; Hematoma in Esophageal Duplication Cyst Masquerading Submucosal Tumor

( Won Il Park ),( Dae Hyeon Cho ),( Ji Eun Oh ),( Hyun Chin Cho ),( Kwang Min Kim ),( Kil Jong Yu ),( Hyoun Soo Lee ),( Man Je Park ),( Sang Goon Shim ),( Chang Uk Jeong ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Esophageal duplication cysts account for a very small percentage of benign esophageal tumor that is usually diagnosed in childhood, but very rare cases remain asymptomatic until adolescence. They may be asymptomatic or present with complications like infection, bleeding, or mass effect. A 19-years-women visited our hospital presenting chest pain and dysphagia. Contrast enhanced computed tomography of the chest showed a heterogeneous density of mass in left lateral wall of distal thoracic esophagus. On endoscopic ultrasound, a heterogeneously echotextured lesion with anechoic components present and no vascular component in Doppler sonogram at intramural location in the lower esophagus was noted. In view of symptoms of dysphagia and possibility of esophageal submucosal tumor, surgical excision through posterolateral thoracotomy was performed. In gross fi nding, a mass measurred 4. 0 x 4. 0 x 2. 0 cm and formed cyst with hematoma formation in it. Histopathologically the cyst was lined by pseudostratifi ed ciliated columnar epithelium surrounded by inner circular and outer longitudinal smooth muscle layers without cartilage. So it was diagnosed as a complicated esophageal duplication cyst with hematoma formation. Esophageal duplication cyst represent rare benign tumor of congenital foregut anomalies. Up to 80% of these cysts are diagnosed in childhood, less than 7% remain asymptomatic until adolescence. Pain and dysphagia are the most common symptoms in adults. Complications may be infections, rupture or bleeding. Diagnosis is usually made by computed tomography and endoscopic ultrasound. The only defi nite treatment is surgical excision. Pathologically, the cyst is covered with nonkeratinizing squamous or ciliated columnar epithelium, and the cyst wall contains two layers of smooth muscle. These fi ndings, accompanied by a lack of cartilage in the cyst wall, can differentiate an esophageal duplication cyst from a bronchogenic cyst.

A Case of Primary Cutaneous CD30(Ki-1)-positive Large Cell Lymphoma Showing Repetitive Spontaneous Regression and Recurrences

Lee, Bong Kil,Kim, Ji Won,Lee, Suk Keung,Lee, Won Woo Korean Dermatological Association 1999 Annals of Dermatology Vol.11 No.2

A Study of Arsenic Profiles by Chemical Etching and Simulation

Won-Chae Jung,Kil-Dong Lee 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.1

For integrated semiconductor devices, the one-, two-, and three-dimensional impurity distributions are very important for the analyzing the devices. The one-dimensional arsenic proles were measured by using secondary ion mass spectroscopy (SIMS), and simulation data were obtained by using the TSUPREM4 and UT-Marlowe programs. The two-dimensional proles of arsenic were directly measured by using the chemical etching-method, and the measured 2D proles were compared with simulation data obtained from TSUPREM4. A Taurus simulation tool was used to obtain the 3D arsenic proles. The simulated data of UT-Marlowe in 1D agreed very well with the SIMS data. The measured two-dimensional transmission electron microscope (TEM) data obtained by using the chemical etching-method matched very well with the results of the TSUPREM4 simulation. The chemical etching and the TEM measurement methods demonstrated and visualized the two-dimensional impurity distributions and structures of the devices.

Directional Ostwald Ripening for Producing Aligned Arrays of Nanowires

Lee, Hye Jin,Yang, U Jeong,Kim, Kyeong Nam,Park, Soojin,Kil, Kye Hyoung,Kim, Jun Soo,Wodtke, Alec M.,Choi, Won Jun,Kim, Myung Hwa,Baik, Jeong Min American Chemical Society 2019 NANO LETTERS Vol.19 No.7

<P>The remarkable electronic and mechanical properties of nanowires have great potential for fascinating applications; however, the difficulties of assembling ordered arrays of aligned nanowires over large areas prevent their integration into many practical devices. In this paper, we show that aligned VO<SUB>2</SUB> nanowires form spontaneously after heating a thin V<SUB>2</SUB>O<SUB>5</SUB> film on a grooved SiO<SUB>2</SUB> surface. Nanowires grow after complete dewetting of the film, after which there is the formation of supercooled nanodroplets and subsequent Ostwald ripening and coalescence. We investigate the growth mechanism using molecular dynamics simulations of spherical Lennard-Jones particles, and the simulations help explain how the grooved surface produces aligned nanowires. Using this simple synthesis approach, we produce self-aligned, millimeter-long nanowire arrays with uniform metal-insulator transition properties; after their transfer to a polymer substrate, the nanowires act as a highly sensitive array of strain sensors with a very fast response time of several tens of milliseconds.</P> [FIG OMISSION]</BR>

Hydrodynamic design of an underwater hull cleaning robot and its evaluation

Lee, Man Hyung,Park, Yu Dark,Park, Hyung Gyu,Park, Won Chul,Hong, Sinpyo,Lee, Kil Soo,Chun, Ho Hwan The Society of Naval Architects of Korea 2012 International Journal of Naval Architecture and Oc Vol.4 No.4

An underwater hull cleaning robot can be a desirable choice for the cleaning of large ships. It can make the cleaning process safe and economical. This paper presents a hydrodynamic design of an underwater cleaning robot and its evaluation for an underwater ship hull cleaning robot. The hydrodynamic design process of the robot body is described in detail. Optimal body design process with compromises among conflicting design requirements is given. Experimental results on the hydrodynamic performance of the robot are given.