392 research outputs found

    Validation of real-time 2D temperature measurement method using CT tunable diode laser absorption spectroscopy

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    Two dimensional (2D) temperature and concentration distribution plays an important role for the combustion structure and the combustor efficiency in engines, burners, gas turbines and so on. Recently, as a multi-species measurement technique with high sensitivity and high response, tunable diode laser spectroscopy (TDLAS) has been developed and applied to the actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, the theoretical and experimental research has been conducted in order to develop the non-contact and fast response 2D temperature and concentration distribution measurement method. The method is based on a computed tomography (CT) using absorption spectra of water vapor at 1388 nm. The computed tomography tunable diode laser spectroscopy (CT-TDLAS) method was employed in engine exhausts to measure 2D temperature distribution. The measured 2D temperature shows a good agreement with the temperature measured by a thermocouple. The temporal and spatial resolutions of this method have also been discussed to demonstrate its applicability to various types of combustor

    Replication of the genetic effects of IFN regulatory factor 5 (IRF5) on systemic lupus erythematosus in a Korean population

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    Recently, two studies provided convincing evidence that IFN regulatory factor 5 (IRF5) gene polymorphisms are significantly associated with systemic lupus erythematosus (SLE) in several white populations. To replicate the association with SLE in an Asian population, we examined the genetic effects in our SLE cohort from a Korean population. A total of 1,565 subjects, composed of 593 cases and 972 controls, were genotyped using the TaqManĀ® (Applied Biosystems, Foster City, CA, USA) method. The genetic effects of polymorphisms on the risk of SLE were evaluated using Ļ‡2 tests and a Mantelā€“Haenszel meta-analysis. Statistical analysis revealed results in the Korean population were similar to the previous reports from white populations. The rs2004640 T allele had a higher frequency in SLE cases (0.385) than controls (0.321; odds ratio (OR) = 1.32, P = 0.0003). In combined analysis, including all seven independent cohorts from the three studies so far, robust and consistent associations of the rs2004640 T allele with SLE were observed. The estimate of risk was OR = 1.44 (range, 1.34ā€“1.55), with an overall P = 1.85 Ɨ 10-23 for the rs2004640 T allele. The haplotype (rs2004640Tā€“rs2280714T) involved in both the alternative splice donor site and the elevated expression of IRF5 also had a highly significant association with SLE (pooled, P = 2.11 Ɨ 10-16). Our results indicate that the genetic effect on the risk of SLE mediated by IRF5 variants can be generally accepted in both white and Asian populations

    New Signature Scheme Using Conjugacy Problem

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    We propose a new digital signature scheme based on a non-commutative group where the conjugacy search problem is hard and the conjugacy decision problem is feasible. We implement our signature scheme in the braid groups and prove that an existential forgery of the implementation under no message attack gives a solution to a variation of conjugacy search problem. Then we discuss performance of our scheme under suggested parameters

    Palliative radiotherapy in patients with a symptomatic pelvic mass of metastatic colorectal cancer

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    <p>Abstract</p> <p>Background</p> <p>To evaluate the palliative role of radiotherapy (RT) and define the effectiveness of chemotherapy combined with palliative RT (CCRT) in patients with a symptomatic pelvic mass of metastatic colorectal cancer.</p> <p>Methods</p> <p>From August 1995 to December 2007, 80 patients with a symptomatic pelvic mass of metastatic colorectal cancer were treated with palliative RT at Samsung Medical Center. Initial presenting symptoms were pain (68 cases), bleeding (18 cases), and obstruction (nine cases). The pelvic mass originated from rectal cancer in 58 patients (73%) and from colon cancer in 22 patients (27%). Initially 72 patients (90%) were treated with surgery, including 64 complete local excisions; 77% in colon cancer and 81% in rectal cancer. The total RT dose ranged 8-60 Gy (median: 36 Gy) with 1.8-8 Gy per fraction. When the <b>Ī±/Ī² </b>for the tumor was assumed to be 10 Gy for the biologically equivalent dose (BED), the median RT dose was 46.8 Gy<sub>10 </sub>(14.4-78). Twenty one patients (26%) were treated with CCRT. Symptom palliation was assessed one month after the completion of RT.</p> <p>Results</p> <p>Symptom palliation was achieved in 80% of the cases. During the median follow-up period of five months (1-44 months), 45% of the cases experienced reappearance of symptoms; the median symptom control duration was five months. Median survival after RT was six months. On univariate analysis, the only significant prognostic factor for symptom control duration was BED ā‰„40 Gy<sub>10 </sub>(p < 0.05), and CCRT was a marginally significant factor (p = 0.0644). On multivariate analysis, BED and CCRT were significant prognostic factors for symptom control duration (p < 0.05).</p> <p>Conclusions</p> <p>RT was an effective palliation method in patients with a symptomatic pelvic mass of metastatic colorectal cancer. For improvement of symptom control rate and duration, a BED ā‰„ 40 Gy<sub>10 </sub>is recommended when possible. Considering the low morbidity and improved symptom palliation, CCRT might be considered in patients with good performance status.</p

    Psychometric Properties of the Hypomania Checklist-32 in Korean Patients with Mood Disorders

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    OBJECTIVE The aim of this study was to examine the validity of the Korean version of the Hypomania Checklist-32, second revision (HCL-32-R2) in mood disorder patients. METHODS A total of 454 patients who diagnosed as mood disorder according to Structured Clinical Interview for DSM-IV Axis I Disorders, clinician version (SCID-CV) (bipolar disorder [BD] I, n=190; BD-II, n=72; and major depressive disorder [MDD], n=192) completed the Korean module of the HCL-32-R2 (KHCL-32-R2). RESULTS The KHCL-32-R2 showed a three-factorial structure (eigenvalue ļ¼ž2) that accounted for 43.26% of the total variance. Factor 1 was labeled "active/elated" and included 16 items; factor 2, "irritable/distractible" and included 9 items; and factor 3 was labeled "risk-taking/indulging" and included 9 items. A score of 16 or more on the KHCL-32-R2 total scale score distinguished between BD and MDD, which yielded a sensitivity of 70% and a specificity of 70%. MDD and BD-II also could be differentiated at a cut-off of 15 with maximized sensitivity (0.67) and specificity (0.66). Cronbach's alpha of KHCL-32-R2 and its subsets (factors 1, 2, and 3) were 0.91, 0.89, 0.81 and 0.79, respectively. Correlations between KHCL-32-R2 and Montgomery- Asberg Depression Rating Scale, Young Mania Rating Scale and Korean version of Mood Disorder Questionnaire were -0.66 (p=0.41), -0.14 (p=0.9), and 0.61 (pļ¼œ0.001), respectively. CONCLUSION The KHCL-32-R2 may be a useful tool in distinguishing between bipolar and depressive patients in clinical settings

    The Association between Disturbed Eating Behavior and Socioeconomic Status: The Online Korean Adolescent Panel Survey (OnKAPS)

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    Background: A limited amount of research, primarily conducted in Western countries, has suggested that higher socioeconomic status (SES) is associated with higher risk of eating disorders (EDs). However, little is known about this association in Asian countries. We examined the association of SES with disturbed eating behavior (DEB) and related factors in Korean adolescents. Subjects A nationwide online panel survey was conducted in a sample of adolescents (n = 6,943, 49.9% girls). DEB was measured with the 26-item Eating Attitudes Test (EAT-26). Participants who scored ā‰„20 on the EAT-26 were considered to have DEB. Participantsā€™ SES was determined based on self-reported household economic status. Results: The prevalence of DEB was 12.7%: 10.5% among boys and 14.8% among girls. Both boys and girls with DEB were more likely to perceive themselves as obese, experience higher levels of stress, and have lower academic achievement. The risk for DEB was significantly higher in boys of higher SES than in those of middle SES (OR = 1.45, 95%CI = 1.05ā€“1.99 for high SES; OR = 5.16, 95%CI: 3.50ā€“7.61 for highest SES). Among girls, higher risk of DEB was associated with the highest and lowest SES (OR = 1.52, 95%CI: 1.13ā€“2.06 for lowest SES; OR = 2.22, 95%CI: 1.34ā€“3.68 for highest SES). Conclusions: Despite the lower prevalence of obesity in Korea compared with Western countries, the prevalence of DEB in Korean adolescents was high, especially among girls. Moreover, the association between SES and DEB followed a U-shaped curve for girls and a J-shaped curve for boys

    Measurement of 129 I Radioactivity in Groundwater of Radioactive Waste Disposal Site

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    The investigation of the environmental radioactivity around the radioactive waste disposal site in Gyeongju is being carried out. The radioactivity of 129 I in groundwater and seaweed are to be measured. The analytical method to measure the radioactivity of 129 I in aqueous media was established. This method contains oxidation-reduction reaction, anion-exchange separation and palladium precipitation. The 129 I radioactivity in the PdI 2 precipitates was measured by using low-energy gamma spectrometer. The counts of peak at 39.6 keV of gamma energy were used for determination of 129 I radioactivity. The chemical recovery was determined by the weights of PdI 2 precipitates. The deionized water and groundwater spiked with 129 I tracer were tested. In the case of deionized water, the relative deviations of measured concentration from spiked one are from 1.1 to 10.7%. The relative deviations of measured radioactivity from spiked one in the groundwater experiments are 2.9 and 3.7%. The measured concentration is in good agreement with spiked one. The groundwater sampled from radioactive waste disposal site was tested. The concentrations of 129 I in the groundwater are below minimum detectable activities of 36.7 and 36.6 mBq/L

    Soluble neprilysin and long-term clinical outcomes in patients with coronary artery disease undergoing percutaneous coronary intervention: a retrospective cohort study

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    Background: Neprilysin has an essential role in regulating fluid balance and vascular resistance, and neprilysin inhibitors have shown beneficial effects in patients with heart failure. However, the potential predictive value of neprilysin levels as a biomarker for cardiovascular risk remains unclear. The aim of this study was to assess the prognostic value of soluble neprilysin (sNEP) levels in patients with ischemic heart disease. Methods: Neprilysin levels were measured in 694 consecutive patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI). These patients were classified into two groups according to their serum levels of neprilysin and categorized into the lower neprilysin group (n = 348) and the higher neprilysin group (n = 346). The primary clinical endpoint was all-cause mortality, and the secondary endpoint was a composite of major adverse cardiac events (MACE). Results: The median sNEP level was 76.0 pg/ml. The median sNEP levels were higher in patients with left ventricular ejection fraction (LVEF) ā‰„40% (77.6 pg/ml, interquartile range 46.6ā€“141.3) than in those with LVEF \u3c 40% (70.0 pg/ml, interquartile range 47.1ā€“100.6; P = 0.032). Among all patients, each clinical outcome and MACE did not differ significantly according to the groups divided into median, tertile, or quartile of sNEP levels during a median follow-up of 28.4 months. We did not find a significant relationship between sNEP levels and clinical outcomes in multivariate Cox regression analysis. Among patients with LVEF \u3c 40%, an increased sNEP level was associated with a higher rate of all-cause death (adjusted hazard ratio 2.630, 95% confidence interval 1.049ā€“6.595, P = 0.039). Conclusion: Serum sNEP levels are not associated with long-term mortality or cardiovascular outcomes after PCI in patients with CAD. In the LVEF \u3c 40% group, increased sNEP levels may be associated with a higher risk of all-cause death

    Enhanced efficiency of crystalline Si solar cells based on kerfless-thin wafers with nanohole arrays

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    Several techniques have been proposed for kerfless wafering of thin Si wafers, which is one of the most essential techniques for reducing Si material loss in conventional wafering methods to lower cell cost. Proton induced exfoliation is one of promising kerfless techniques due to the simplicity of the process of implantation and cleaving. However, for application to high efficiency solar cells, it is necessary to cope with some problems such as implantation damage removal and texturing of (111) oriented wafers. This study analyzes the end-of-range defects at both kerfless and donor wafers and ion cutting sites. Thermal treatment and isotropic etching processes allow nearly complete removal of implantation damages in the cleaved-thin wafers. Combining laser interference lithography and a reactive ion etch process, a facile nanoscale texturing process for the kerfless thin wafers of a (111) crystal orientation has been developed. We demonstrate that the introduction of nanohole array textures with an optimal design and complete damage removal lead to an improved efficiency of 15.2% based on the kerfless wafer of a 48 mu m thickness using the standard architecture of the Al back surface field
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