86 research outputs found

    One-step synthesis of PEG-coated gold nanoparticles by rapid microwave heating

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    Polyethylene Glycol- (PEG-) coated gold nanoparticles (PEG-AuNPs) are synthesized by a one-step route with rapid microwave heating. Homogeneous nucleation of the primary gold particles is enhanced by increasing the applied microwave power during the initial stage of the synthesis, increasing the temperature ramping rate (R r) and resulting in decreased size and improved uniformity of the synthesized PEG-AuNPs. Using rapid microwave heating, we successfully produce uniform colloidal PEG-AuNPs with an average diameter of 14.3 ± 2.5 nm within a few minutes. By appropriate tuning of the growth parameters, microwave synthesis can produce largely colloidal PEG-AuNPs with high uniformity. © 2013 Seung Kwon Seol et al.Link_to_subscribed_fulltex

    Meniscus-Guided Micro-Printing of Prussian Blue for Smart Electrochromic Display

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    Using energy-saving electrochromic (EC) displays in smart devices for augmented reality makes cost-effective, easily producible, and efficiently operable devices for specific applications possible. Prussian blue (PB) is a metal-organic coordinated compound with unique EC properties that limit EC display applications due to the difficulty in PB micro-patterning. This work presents a novel micro-printing strategy for PB patterns using localized crystallization of FeFe(CN)(6) on a substrate confined by the acidic-ferric-ferricyanide ink meniscus, followed by thermal reduction at 120 degrees C, thereby forming PB. Uniform PB patterns can be obtained by manipulating printing parameters, such as the concentration of FeCl3 center dot K3Fe(CN)(6), printing speed, and pipette inner diameter. Using a 0.1 M KCl (pH 4) electrolyte, the printed PB pattern is consistently and reversibly converted to Prussian white (CV potential range: -0.2-0.5 V) with 200 CV cycles. The PB-based EC display with a navigation function integrated into a smart contact lens is able to display directions to a destination to a user by receiving GPS coordinates in real time. This facile method for forming PB micro-patterns could be used for advanced EC displays and various functional devices

    The Prevalence of Chronic Diseases among Migrants in Korea According to Their Length of Stay and Residential Status

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    Background: Migrant health is becoming public health issues, as the migrant populations are increasing and their length of stayis prolonged. This study aims to analyze the differences in prevalence of chronic diseases among migrants according to length ofstay and residential status.Methods: An initial population pool were 3,024 who were assessed with health screening programs by Migrant Health Association.2,459 migrants were selected for final analysis. Via Stata 10 we conducted univariate logistic regression analysis to examine theeffects of their length of stay and residential status on the prevalence of hypertension, diabetes, dyslipidemia, and obesity. In thefinal analysis, the result of each sex was adjusted for age, nationality, length of stay, and residential status via multiple logisticregression analysis.Results: Longer length of stay tends to increase the prevalence of hypertension in male; 4-6 year stay-duration groupdemonstrated statistically significant excess compared to 1 year or less stay-duration group (adjusted odds ratio [OR], 1.39;confidence interval [CI], 1.01 to 1.92). After adjustment, male migrants stayed more than 7 year showed considerably higherdyslipidemia than male migrants stayed less than 1 year (adjusted OR, 1.95; CI, 1.05 to 3.64). Compared to the group with 1 yearor less stay-duration, the prevalence of obesity in male was significantly higher among 4-6 year (adjusted OR, 1.65; CI, 1.17 to 2.32)and 7 year or more stay-duration group (adjusted OR, 1.65; CI, 1.11 to 2.45).Conclusion: Longer length of stay correlated to higher prevalence of hypertension, dyslipidemia, and obesity among somepopulation of migrants. So more researches and new developing policies are needed for this problem.OAIID:oai:osos.snu.ac.kr:snu2012-01/102/0000052039/7SEQ:7PERF_CD:SNU2012-01EVAL_ITEM_CD:102USER_ID:0000052039ADJUST_YN:YEMP_ID:A077862DEPT_CD:801CITE_RATE:0FILENAME:52 The Prevalence of Chronic Diseases among Migrants in Korea According.pdfDEPT_NM:의학과EMAIL:[email protected]_YN:NCONFIRM:

    Two-year Clinical Outcomes of Patients with Long Segments Drug-Eluting Stents: Comparison of Sirolimus-Eluting Stent with Paclitaxel-Eluting Stent

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    Limited data are available on the long-term clinical efficacy of drug-eluting stent (DES) in diffuse long lesions. From May 2006 to May 2007, a total of 335 consecutive patients (374 lesions) were underwent percutaneous coronary intervention with implantation of long DES (≥ 30 mm) in real world practice. Eight-month angiographic outcomes and 2-yr clinical outcomes were compared between SES (n = 218) and PES (n = 117). Study endpoints were major adverse cardiac events including cardiac death, myocardial infarction, target-lesion revascularization, target-vessel revascularization and stent thrombosis. Baseline characteristics were similar in the two groups as were mean stent length (44.9 ± 15.2 mm in SES and 47.4 ± 15.9 in PES, P = 0.121). Late loss at 8 months follow-up was significantly lower in SES than in PES group (0.4 ± 0.6 mm in SES vs 0.7 ± 0.8 mm in PES, P = 0.007). Mean follow-up duration was 849 ± 256 days, and 2-yr cumulative major adverse cardiac events were significantly lower in the SES than in the PES group (5.5% in SES vs 15.4% in PES, P = 0.003). In conclusion, long-term DES use in diffuse long coronary lesions is associated with favorable results, with SES being more effective and safer than PES in this real-world clinical experience

    Pharmacogenomic profiling reveals molecular features of chemotherapy resistance in IDH wild-type primary glioblastoma

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    Background Although temozolomide (TMZ) has been used as a standard adjuvant chemotherapeutic agent for primary glioblastoma (GBM), treating isocitrate dehydrogenase wild-type (IDH-wt) cases remains challenging due to intrinsic and acquired drug resistance. Therefore, elucidation of the molecular mechanisms of TMZ resistance is critical for its precision application. Methods We stratified 69 primary IDH-wt GBM patients into TMZ-resistant (n = 29) and sensitive (n = 40) groups, using TMZ screening of the corresponding patient-derived glioma stem-like cells (GSCs). Genomic and transcriptomic features were then examined to identify TMZ-associated molecular alterations. Subsequently, we developed a machine learning (ML) model to predict TMZ response from combined signatures. Moreover, TMZ response in multisector samples (52 tumor sectors from 18 cases) was evaluated to validate findings and investigate the impact of intra-tumoral heterogeneity on TMZ efficacy. Results In vitro TMZ sensitivity of patient-derived GSCs classified patients into groups with different survival outcomes (P = 1.12e−4 for progression-free survival (PFS) and 3.63e−4 for overall survival (OS)). Moreover, we found that elevated gene expression of EGR4, PAPPA, LRRC3, and ANXA3 was associated to intrinsic TMZ resistance. In addition, other features such as 5-aminolevulinic acid negative, mesenchymal/proneural expression subtypes, and hypermutation phenomena were prone to promote TMZ resistance. In contrast, concurrent copy-number-alteration in PTEN, EGFR, and CDKN2A/B was more frequent in TMZ-sensitive samples (Fishers exact P = 0.0102), subsequently consolidated by multi-sector sequencing analyses. Integrating all features, we trained a ML tool to segregate TMZ-resistant and sensitive groups. Notably, our method segregated IDH-wt GBM patients from The Cancer Genome Atlas (TCGA) into two groups with divergent survival outcomes (P = 4.58e−4 for PFS and 3.66e−4 for OS). Furthermore, we showed a highly heterogeneous TMZ-response pattern within each GBM patient usingin vitro TMZ screening and genomic characterization of multisector GSCs. Lastly, the prediction model that evaluates the TMZ efficacy for primary IDH-wt GBMs was developed into a webserver for public usage (http://www.wang-lab-hkust.com:3838/TMZEP) Conclusions We identified molecular characteristics associated to TMZ sensitivity, and illustrate the potential clinical value of a ML model trained from pharmacogenomic profiling of patient-derived GSC against IDH-wt GBMs

    Fabrication of freestanding metallic micro hollow tubes by template-free localized electrochemical deposition

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    [[abstract]]We describe a technique to fabricate three-dimensional (3D), freestanding metallic micro hollow tubes by template-free localized electrochemical deposition. The features of the grown structure are controlled by the field strength distribution in its proximity that depends on the applied voltage and the microelectrode-structure distance (L). The formation of micro hollow tubes is induced by the enhanced electric field at the microelectrode rim for small L values (a few micrometers or less) and high applied voltages.[[fileno]]2060117010082[[department]]工程與系統科學
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