Evaluation of Hot Deformation and Dynamic Recrystallization Behaviors of Advanced Reduced-Activated Alloy (ARAA)

Sang‑Wook Kim,Hyeon‑Woo Son,Taek‑Kyun Jung,Young‑Bum Chun,Yi‑Hyun Park,Ji‑Woon Lee,Soong‑Keun Hyun 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

The hot deformation behavior of advanced reduced-activation alloy (ARAA) was investigated using hot torsion tests. Thefl ow stress decreased as deformation temperature increased and as strain rate decreased. The fl ow behavior demonstratedthe typical dynamic recrystallization (DRX). Based on the constitutive analysis of peak stress, the activation energy for hotdeformation was found to be 330.3 kJ mol −1 . Peak stress was analyzed as a function of the Zener–Hollomon parameter, andcalculated and experimental values were in good agreement. A DRX kinetic model for ARAA was derived with deformationconditions based on the Avrami-type model. It was confi rmed that the volume fraction of dynamically recrystallized grainsincreased as deformation temperature increased and as strain rate decreased. The necklace structure and grain boundarybulging were observed in the deformed microstructure of ARAA. The suggested DRX mechanism for ARAA during hotworking is discontinuous DRX.

산업단지 및 일반생활 지역의 공기 중 톨루엔에 대한 개인노출 및 생체시료의 상관성 분석

이병준(Byoungjun Lee),허 정(Jung Heo),정다영(Dayoung Jung),김순신(Sunshin Kim),류현수(Hyeon-Su Ryu),최민지(Min-Ji Choi),솨이지엔페이(Jian-Fei Shuai),임성국(Sung-Guk Im),양원호(Wonho Yang) 한국환경보건학회 2017 한국환경보건학회지 Vol.43 No.4

Objectives: The purpose of this study was to assess the correlation relationship between personal exposure and urinary hippuric acid in biological monitoring for airborne toluene in an industrial complex and in general environments. Methods: Personal exposure to toluene and its metabolite, hippuric acid, in urine were simultaneously measured in occupational environments area near an industrial complex and in general environments. The study subjects were divided into three types: 137 workers who use organic solvents in the workplace, 210 residents living near a dyeing industrial complex, and 379 residents living in general environments. The toluene exposures of workers and residents were measured by a passive sampler for four days. The urine of participants was sampled when the passive samplers of personal exposure were collected. Results: The toluene and hippuric acid concentrations of workers were the highest, followed by the concentrations of residents living near a dyeing industrial complex and residents living in general environments. The coefficient of correlation between the concentrations of toluene and hippuric acid among workers was 0.749 (p<0.01) in the workplace. On the contrary, correlations between the concentrations of toluene and hippuric acid among residents living near a dyeing industrial complex and residents living in general environments were all not significant. The relationship between the concentrations of hippuric acid and toluene in three types could be described by the exponential growth model. Conclusions: This study analyzed the relationships between toluene exposure and the concentrations of hippuric acid in urine in high, middle, and low exposure environments, and could be described by the exponential growth model.

Nanogenerators: Fully Rollable Transparent Nanogenerators Based on Graphene Electrodes (Adv. Mater. 19/2010)

Choi, Dukhyun,Choi, Min-Yeol,Choi, Won Mook,Shin, Hyeon-Jin,Park, Hyun-Kyu,Seo, Ju-Seok,Park, Jongbong,Yoon, Seon-Mi,Chae, Seung Jin,Lee, Young Hee,Kim, Sang-Woo,Choi, Jae-Young,Lee, Sang Yoon,Kim, Jo WILEY-VCH Verlag 2010 ADVANCED MATERIALS Vol.22 No.19

<B>Graphic Abstract</B> <P>The cover shows an image of fully rollable transparent nanogenerators synthesized using chemical vapor deposition grown large-scale graphene sheets as transparent electrodes and piezoelectric ZnO nanorod arrays. Sang-Woo Kim, Jae-Young Choi, and co-workers report on p. 2187 the electrical and structural stability of the nanogenerators, with excellent charge scavenging performance under external mechanical loads such as bending and rolling. This study shows that graphene-based nanogenerators are very promising for self-powered rollable transparent device applications. <img src='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content.gif' alt='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content'> </P>

Comparative Outcome after Treatment for Synchronous vs. Metachronous Colorectal Cancer Liver Metastasis

Sang Min Youn,Jin Seok Heo,Dong Wook Choi,Seong Hyeon Yun,Ho Kyung Chun,Woo Yong Lee,Seong Ho Choi,Hee Cheol Kim,Yong Bum Cho 한국간담췌외과학회 2010 한국간담췌외과학회지 Vol.14 No.3

Purpose: This study was designed to compare outcomes in patients who underwent hepatectomy or radiofrequency thermal ablation (RFA) for synchronous or metachronous colorectal liver metastases (CLM). Methods: One hundred twenty-two patients who underwent hepatectomy or RFA for their first CLM between 2001 and 2004 were enrolled in this study. The patients were divided into two groups (synchronous [N=77] and metachronous [N=45] CLM). Patient characteristics, clinicopathologic features, long-term outcomes, and prognostic factors were analyzed retrospectively. Results: There were no significant differences in the 5-year disease-free and overall survival rates between the synchronous and metachronous CLM groups (36.2% vs. 37.2%, p=0.78; and 53.0% vs. 54.4%, p=0.82, respectively). Patients in the synchronous CLM group underwent more bilobar hepatic resections, intra-operative RFA, or co-modality treatments than the metachronous CLM group (p=0.035). The surgical resection group had a longer disease-free survival, but not overall survival than the RFA group. Greater N stage and female gender were associated with a worse prognosis in overall survival; N0 stage and surgical resection were good prognostic factors for disease-free survival. N stage and surgical resection were also statistically significant prognostic factors based on multivariate analysis. Conclusion: The synchronicity of CLM is not a significant prognostic factor, but the clinicopathologic characteristics that reflect more disseminated disease than metachronous metastasis are significant prognostic factors. Tumor characteristics and aggressiveness may be more important for prognosis than chronology.

Age-dependent alteration in the expression of oligodendrocyte-specific protein in the gerbil hippocampus

Lee, Hyang-Ah,Park, Joon Ha,Kim, Dae Won,Lee, Choong-Hyun,Hwang, In Koo,Kim, Hyeyoung,Shin, Myoung Cheol,Cho, Jun Hwi,Lee, Jae-Chul,Noh, Yoohun,Kim, Sung-Su,Won, Moo-Ho,Ahn, Ji Hyeon SPANDIDOS PUBLICATIONS 2018 MOLECULAR MEDICINE REPORTS Vol.17 No.3

<P>Oligodendrocytes are myelin-forming cells in the central nervous system. Research into the effects of aging on oligodendrocyte protein expression remains limited. The present study aimed to determine the alterations in oligodendrocyte-specific protein (OSP) expression in the gerbil hippocampus at 1, 2, 3, 4, 6 and 24 months of age with western blot and immunohistochemistry analyses. OSP expression levels in the hippocampus were highest at 6 months of age. OSP immunoreactivity was identified in numerous cell bodies at 1 month, although the number of OSP immunoreactive cells was different according to hippocampal subregion. The number of OSP immunoreactive cells significantly decreased at 2 months and, thereafter, numbers decreased gradually. The detection of OSP immunoreactive fibers was negligible in all layers in the hippocampal subregions until 4 months. OSP immunoreactive fibers were abundant at 6 and 24 months, although the fiber distribution patterns in the CA1-3 areas and dentate gyrus were different. The results demonstrated that OSP expression in the gerbil hippocampus was age-dependent. The detection of OSP immunoreactive cell bodies and fibers was significantly different according to the layers of hippocampal subregions, indicating that myelination may be continuously altered in the hippocampus during normal aging.</P>

Letter to the Editor : A Case of Capecitabine and Cisplatin-induced Cutaneous Hyperpigmentation

( Sang Hyeon Hwang ),( Ji Hye Park ),( Chong Won Choi ),( Ga Young Lee ),( Won Serk Kim ) 대한피부과학회 2014 大韓皮膚科學會誌 Vol.52 No.3

The sudden appearance of multiple hyperpigmentation lesions on palms and soles is a rare phenomenon. We here report a case of focal acral hyperpigmentation in a patient undergoing chemotherapy with capecitabine and cisplatin. A 70-year-old man undergoing chemotherapy with capecitabine and cisplatin for metastatic gastric cancer was referred to our department with several pigmented macules and patches on the palms and soles (Fig. 1). The lesions appeared suddenly after the first cycle of treatment (cumulative dose, 35 g of capecitabine and 80 mg of cisplatin). Histopathological examination of the pigmented macules revealed melanocytes and melanin in the basal layer (Fig. 2). We care- fully followed the patient for any changes in color, size, and shape of the lesions, but the pigmented lesions persisted without any change until the patient died of pneumonia after sixth cycles of chemotherapy. Capecitabine is an oral antineoplastic agent, which is converted to 5-fluorouracil (5-FU) in the body. A well-known side effect of 5-FU on the skin is the hand-foot syndrome (HFS) or palmar-plantar erythrodysaesthesia1. However, acral hyperpigmentation is rarely reported. A previous report of capecitabine-induced hyperpigmentation noted a similar, but more generalized, distribution of the pigmented macules seen in this case2. Conversely, cisplatin-induced hyperpigmentation is rarely reported, and the predilection sites, such as the periungual areas, are prone to repeated irritation3. It has been proposed that a combination of altered immune surveillance and certain anatomic trophic factors present in the skin of the palms and soles play a role in the development of palmoplantar pigmented lesions4. In this case, it is thought that capecitabine contributed more to the development of the lesions on the palms and soles, although both capecitabine and cisplatin may be responsible for the development of hyperpigmentation. This case report adds novel information to the data available on capecitabine and cisplatin-induced cutaneous hyperpigmentation. Although cutaneous hyperpigmentation is not a common side effect in capecitabine and cisplatin treatment 2, 3, hyperpigmentation due to these medications may be more common than reported, and clinicians should hence be aware of this focal cutaneous adverse effect.

Usefulness of dermoscopy for diagnosis of pigmented spindle cell nevus

( Sang Hwa Han ),( Kang Hoon Lee ),( Joon Hee Kim ),( Myeong Hyeon Yang ),( Min Soo Jang ),( Kee Suck Suh ) 대한피부과학회 2015 대한피부과학회 학술발표대회집 Vol.67 No.1

Pigmented spindle cell nevus (PSCN), also known as Reed nevus, is a melanocytic lesion clinically characterized by well circumscribed hyperpigmented flat macule. PSCN should be differentiated from Spitz nevus, dysplastic nevus, and malignant melanoma. Histologically, symmetrical proliferation and linear band-like arrangement of pigmented melanophages in the papillary dermis can be seen. And uniform, narrow, elongated, and spindle shaped cells were vertically oriented in the dermal-epidermal junction. A 27-year-old male presented with solitary well demarcated 4 x 5 mm sized blackish macule on the left arm. On dermoscopy, blackish homogenous pattern and partially distributed starburst pattern were found. Histopathologic findings showed symmetrical proliferation and linear band-like arrangement of pigmented melanophages in the papillary dermis. And uniform, narrow, elongated pigmented spindle cells were vertically oriented in dermal-epidermal junction. On the basis of these clinical, dermoscopic, and histological findings, the diagnosis of PSCN was made. Dermoscopy allows one to see surface and subsurface skin structures not easily detected by the naked eye. The typical dermoscopic findings of PSCN were reported as starburst, homogenous, globular, or peripheral reticular patterns. Herein, we report a case of PSCN for whom dermoscopy was used as an helpful diagnostic tool.

Metformin Suppresses Systemic Autoimmunity in <i>Roquin^san/san</i> Mice through Inhibiting B Cell Differentiation into Plasma Cells via Regulation of AMPK/mTOR/STAT3

Lee, Seon-Yeong,Moon, Su-Jin,Kim, Eun-Kyung,Seo, Hyeon-Beom,Yang, Eun-Ji,Son, Hye-Jin,Kim, Jae-Kyung,Min, Jun-Ki,Park, Sung-Hwan,Cho, Mi-La American Association of Immunologists 2017 Journal of Immunology Vol. No.

<P>Circulating autoantibodies and immune complex deposition are pathological hallmarks of systemic lupus erythematosus (SLE). B cell differentiation into plasma cells (PCs) and some T cell subsets that function as B cell helpers can be therapeutic targets of SLE. Mechanistic target of rapamycin (mTOR) signaling is implicated in the formation of B cells and germinal centers (GCs). We assessed the effect of metformin, which inhibits mTOR, on the development of autoimmunity using Roquin(san/san) mice. Oral administration of metformin inhibited the formation of splenic follicles and inflammation in kidney and liver tissues. It also decreased serum levels of anti-dsDNA Abs without affecting serum glucose levels. Moreover, metformin inhibited CD21(high) CD23(low) marginal zone B cells, B220(+)GL7(+) GC B cells, B220(-)CD138(+) PCs, and GC formation. A significant reduction in ICOS+ follicular helper T cells was found in the spleens of the metformin-treated group compared with the vehicle-treated group. In addition, metformin inhibited Th17 cells and induced regulatory T cells. These alterations in B and T cell subsets by metformin were associated with enhanced AMPK expression and inhibition of mTOR-STAT3 signaling. Furthermore, metformin induced p53 and NF erythroid-2-related factor-2 activity in splenic CD4(+) T cells. Taken together, metformin-induced alterations in AMPK-mTOR-STAT3 signaling may have therapeutic value in SLE by inhibiting B cell differentiation into PCs and GCs.</P>

Prediction of Future Osteoporotic Fracture Occurrence by Genetic Profiling: A 6-Year Follow-Up Observational Study

Lee, Seung Hun,Cho, Eun-Hee,Ahn, Seong Hee,Kim, Hyeon-Mok,Lim, Kyeong-Hye,Kim, Beom-Jun,Kim, Sang-Wook,Kim, Tae-Ho,Kim, Shin-Yoon,Kim, Ghi Su ENDOCRINE SOCIETY 2016 The Journal of clinical endocrinology & metabolism Vol.101 No.3

<P>Context: Heredity is an important risk factor for osteoporotic fracture, but it remains unclear whether genetic factors improve the predictability of future fracture occurrence. Objective: To compare an integration model of genetic profiling with the current model for predicting future fracture occurrence. Design and Setting: A retrospective observational cohort study. Participants: Postmenopausal women aged 45-93 years who were untreated (n = 117), hormone-treated (n = 491), or bisphosphonate (BP)-treated (n = 415), with a mean 6.1-year follow-up. Main Outcomes Measures: The main outcome was incident fractures. Ninety-five single nucleotide polymorphisms were genotyped. We calculated the Korean-specific genetic risk score 35 (GRS35) from 35 single nucleotide polymorphisms associated with osteoporosis-related traits at the baseline visit. Results: Osteoporotic fracture occurred more frequently in the highest GRS35 tertile group than in the lower two tertile groups after adjustments for confounders (hazard ratio [HR], 1.73; 95% confidence interval [CI], 1.17-2.55). The associations of the GRS35 with incident fracture were only significant in the BP group (HR, 2.25; 95% CI, 1.28-3.95) and not in the untreated (HR, 1.26; 95% CI, 0.34-4.66) and hormone-treated (HR, 1.21; 95% CI, 0.62-2.36) groups. Integration of the GRS35 into the current model further improved its predictability for incident fracture occurrence by 6.3% (P = .010). Conclusions: Genetic profiling can more accurately predict future fracture risk, especially in individuals taking BPs.</P>

Redox-Sensitive Facet Dependency in Etching of Ceria Nanocrystals Directly Observed by Liquid Cell TEM

Sung, Jongbaek,Choi, Back Kyu,Kim, Byunghoon,Kim, Byung Hyo,Kim, Joodeok,Lee, Donghoon,Kim, Sungin,Kang, Kisuk,Hyeon, Taeghwan,Park, Jungwon American Chemical Society 2019 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.141 No.46

<P>Defining the redox activity of different surface facets of ceria nanocrystals is important for designing an efficient catalyst. Especially in liquid-phase reactions, where surface interactions are complicated, direct investigation in a native environment is required to understand the facet-dependent redox properties. Using liquid cell TEM, we herein observed the etching of ceria-based nanocrystals under the control of redox-governing factors. Direct nanoscale observation reveals facet-dependent etching kinetics, thus identifying the specific facet ({100} for reduction and {111} for oxidation) that governs the overall etching under different chemical conditions. Under each redox condition, the contribution of the predominant facet increases as the etching reactivity increases.</P> [FIG OMISSION]</BR>