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  1. Article ; Online: Effect of electron blocking layer on the efficiency of AlGaN mid-ultraviolet light emitting diodes.

    Pandey, A / Shin, W J / Liu, X / Mi, Z

    Optics express

    2019  Volume 27, Issue 12, Page(s) A738–A745

    Abstract: The performance of AlGaN-based mid and deep ultraviolet light emitting diodes (LEDs) is severely limited by electron overflow and by the poor hole injection into the device active region. We have studied the effect of various electron blocking layers on ... ...

    Abstract The performance of AlGaN-based mid and deep ultraviolet light emitting diodes (LEDs) is severely limited by electron overflow and by the poor hole injection into the device active region. We have studied the effect of various electron blocking layers on the performance of AlGaN LEDs operating at ~280 nm. It is observed that, compared to conventional p-type electron blocking layer, the incorporation of an n-type AlN/AlGaN superlattice electron blocking layer before the active region can significantly improve the device performance by reducing electron overflow without compromising hole injection. Direct on-wafer measurement showed an external quantum efficiency ~4.4% and wall-plug efficiency ~2.8% by optimizing the design of n-type AlN/AlGaN superlattice electron blocking layer, which is nearly a factor of five to ten times better than identical devices but with the incorporation of a conventional p-type electron blocking layer.
    Language English
    Publishing date 2019-06-27
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.27.00A738
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Ultrasonographic optic nerve sheath diameter is correlated with arterial carbon dioxide concentration during reperfusion in liver transplant recipients.

    Seo, H / Kim, Y-K / Shin, W J / Hwang, G S

    Transplantation proceedings

    2013  Volume 45, Issue 6, Page(s) 2272–2276

    Abstract: Background: Cerebral blood flow and intracranial pressure (ICP) has been known to be increased after graft reperfusion during liver transplantation, which was correlated with arterial carbon dioxide concentration (PaCO2). Ultrasonographic measurement of ...

    Abstract Background: Cerebral blood flow and intracranial pressure (ICP) has been known to be increased after graft reperfusion during liver transplantation, which was correlated with arterial carbon dioxide concentration (PaCO2). Ultrasonographic measurement of optic nerve sheath diameter (ONSD) is a simple and noninvasive method for evaluating ICP. We investigated the correlation between ONSD and the PaCO2 during reperfusion in liver transplant recipients.
    Methods: Twenty liver transplant recipients with end-stage liver disease were enrolled. We measured ONSD and PaCO2 at 6 time points: preinduction, preanhepatic phase, anhepatic phase, 5 minutes after reperfusion, 30 minutes after reperfusion, and neohepatic phase. Pearson correlation analysis and receiver operating characteristics (ROC) curve analysis were performed.
    Results: ONSD measured 5 minutes after reperfusion was significantly higher compared with the other time points. Differences in ONSD between the anhepatic phase and 5 minutes after reperfusion demonstrated significant correlations with both PaCO2 at the anhepatic phase and 5 minutes after reperfusion (both P < .001). On the ROC curve analysis, PaCO2 of 35 mm Hg at the anhepatic phase could be used to indicate ≥20% changes in ONSD after reperfusion. There were significant increases in ONSD after graft reperfusion in liver transplant recipients with PaCO2 ≥ 35 mm Hg at the anhepatic phase (P = .004).
    Conclusion: ONSD was increased just after reperfusion, which demonstrated good correlation with PaCO2 during reperfusion in liver transplant recipients. This finding suggests that the carbon dioxide can play a key role in increasing ONSD during hepatic graft reperfusion.
    MeSH term(s) Adult ; Biomarkers/blood ; Carbon Dioxide/blood ; Cerebrovascular Circulation ; End Stage Liver Disease/diagnosis ; End Stage Liver Disease/physiopathology ; End Stage Liver Disease/surgery ; Female ; Humans ; Intracranial Pressure ; Liver Transplantation/methods ; Male ; Middle Aged ; Monitoring, Intraoperative/methods ; Myelin Sheath/diagnostic imaging ; Optic Nerve/diagnostic imaging ; Perfusion ; Predictive Value of Tests ; Prospective Studies ; ROC Curve ; Time Factors ; Ultrasonography
    Chemical Substances Biomarkers ; Carbon Dioxide (142M471B3J)
    Language English
    Publishing date 2013-07
    Publishing country United States
    Document type Journal Article ; Observational Study
    ZDB-ID 82046-5
    ISSN 1873-2623 ; 0041-1345
    ISSN (online) 1873-2623
    ISSN 0041-1345
    DOI 10.1016/j.transproceed.2012.12.032
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Serial monitoring of B-type natriuretic Peptide in management of heart failure after liver transplantation in a patient with Budd-Chiari syndrome: case report.

    Shin, W J / Kim, Y K / Hwang, G S

    Transplantation proceedings

    2010  Volume 42, Issue 7, Page(s) 2791–2793

    Abstract: Liver transplantation (LT) is an effective treatment option in patients with Budd-Chiari syndrome and end-stage liver disease. However, the procedure may lead to a sudden increase in cardiac preload, which in turn may cause heart failure. Although assays ...

    Abstract Liver transplantation (LT) is an effective treatment option in patients with Budd-Chiari syndrome and end-stage liver disease. However, the procedure may lead to a sudden increase in cardiac preload, which in turn may cause heart failure. Although assays of B-type natriuretic peptide (BNP) are increasingly used in diagnosis, management, and prediction of heart failure, the role of BNP after LT has not been well defined. Herein, we describe the case of a 56-year-old woman with Budd-Chiari syndrome who underwent LT and in whom heart failure was successfully managed using serial monitoring of BNP concentrations. The BNP concentration increased to 1735 pg/mL on postoperative day 4, and decreased to 180 pg/mL on postoperative day 19, at which time inotropic agents were discontinued.
    MeSH term(s) Blood Pressure ; Budd-Chiari Syndrome/surgery ; Cardiotonic Agents/therapeutic use ; Female ; Heart Failure/drug therapy ; Heart Failure/physiopathology ; Heart Failure/therapy ; Heart Rate ; Humans ; Liver Cirrhosis/surgery ; Liver Function Tests ; Liver Transplantation/adverse effects ; Middle Aged ; Monitoring, Physiologic/methods ; Natriuretic Peptide, Brain/blood ; Vascular Resistance
    Chemical Substances Cardiotonic Agents ; Natriuretic Peptide, Brain (114471-18-0)
    Language English
    Publishing date 2010-09
    Publishing country United States
    Document type Case Reports ; Journal Article
    ZDB-ID 82046-5
    ISSN 1873-2623 ; 0041-1345
    ISSN (online) 1873-2623
    ISSN 0041-1345
    DOI 10.1016/j.transproceed.2010.04.063
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Pretransplant Resting Heart Rate and Its Association With All-Cause Mortality in Liver Transplant Recipients.

    Kwon, H-M / Jun, I-G / Jung, K-W / Moon, Y-J / Shin, W-J / Song, J-G / Hwang, G-S

    Transplantation proceedings

    2017  Volume 49, Issue 5, Page(s) 1092–1096

    Abstract: Background: The importance of heart rate (HR) measurement as a prognostic factor has been recognized in many clinical conditions, such as hypertension, coronary artery disease, or heart failure. Patients with liver cirrhosis tend to have increased ... ...

    Abstract Background: The importance of heart rate (HR) measurement as a prognostic factor has been recognized in many clinical conditions, such as hypertension, coronary artery disease, or heart failure. Patients with liver cirrhosis tend to have increased resting HR as consequence of hyperdynamic circulation. In the current study, we examined whether pretransplant resting increased HR is associated with overall mortality in cirrhotic patients following liver transplantation (LT).
    Patients and methods: We retrospectively collected and analyzed the data of 881 liver recipients who underwent LT surgery between October 2009 and September 2012. Patients were categorized into 3 groups by tertile of resting HR as follows: tertile 1 group, HR ≤ 65 beats per minute (bpm); tertile 2 group, HR 66 to 80 bpm; and tertile 3 group, HR > 80 bpm.
    Results: Kaplan-Meier analysis showed that the all-cause mortality rate was significantly different according to tertiles of HR (P = .016, log-rank test). The multivariate Cox regression analysis showed that tertile 3 group was significantly associated with higher risk for all-cause mortality (hazard ratio 1.83, 95% confidence interval, 1.10-3.07; P = .021) compared with tertile 1 group, after adjusting for clinically significant variables in univariate analysis.
    Conclusions: Our results demonstrate that pretransplant resting tachycardia can identify patients at high risk of death in cirrhotic patients following LT, suggesting that further study will be need to clarify relationship between HR burden and sympathetic cardiac neuropathy.
    Language English
    Publishing date 2017-06
    Publishing country United States
    Document type Journal Article
    ZDB-ID 82046-5
    ISSN 1873-2623 ; 0041-1345
    ISSN (online) 1873-2623
    ISSN 0041-1345
    DOI 10.1016/j.transproceed.2017.03.043
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Pretransplant Left Ventricular Dysfunction Adversely Affects Perioperative Outcomes in Pediatric Liver Transplantation: A Retrospective Observational Study.

    Jang, D-M / Jun, I-G / Moon, Y-J / Shin, W-J / Song, J-G / Hwang, G-S

    Transplantation proceedings

    2016  Volume 48, Issue 10, Page(s) 3328–3335

    Abstract: Background: Although left ventricular diastolic dysfunction (LVDD) is a pronounced feature of adult cirrhotic cardiomyopathy and a major predictor of poor outcomes following liver transplantation (LT), little is known about if pretransplant cardiac ... ...

    Abstract Background: Although left ventricular diastolic dysfunction (LVDD) is a pronounced feature of adult cirrhotic cardiomyopathy and a major predictor of poor outcomes following liver transplantation (LT), little is known about if pretransplant cardiac dysfunction affects perioperative outcomes in pediatric LT.
    Methods: We retrospectively evaluated pretransplant clinical and Doppler echocardiographic data for 45 consecutive pediatric LT recipients who were treated between 2007 and 2013 (median age = 15 months; interquartile range = 9 to 78 months). LVDD was defined according to the cirrhotic cardiomyopathy criteria, and the myocardial performance index (MPI) was measured using tissue Doppler imaging. Intraoperative data and hospitalization days following LT were compared.
    Results: LVDD and MPI ≥0.5 (defined as a z score ≥2) were observed in 13% and 27% of patients, respectively. Patients with an MPI ≥0.5 demonstrated the increased accumulation of lactate at the end of their LT operation (mean = 2.48 vs 0.82; P = .026) compared with patients with an MPI <0.5. The hospital stay was longer in patients with LVDD (median = 46 days vs 30 days; P = .041) and patients with an MPI ≥0.5 (median = 38 days vs 29 days; P = .014) compared with patients without LVDD and MPI <0.5, respectively.
    Conclusions: LVDD might be less prevalent (13%) in pediatric patients compared with adults. However, pretransplant cardiac dysfunction in patients with LVDD and an MPI ≥0.5 adversely affects perioperative outcomes, necessitating that such pediatric LT recipients be cautiously observed perioperatively.
    MeSH term(s) Child ; Child, Preschool ; Echocardiography, Doppler ; Female ; Humans ; Infant ; Length of Stay ; Liver Transplantation/adverse effects ; Male ; Postoperative Complications/epidemiology ; Postoperative Complications/etiology ; Preoperative Period ; Prevalence ; Retrospective Studies ; Severity of Illness Index ; Ventricular Dysfunction, Left/complications ; Ventricular Dysfunction, Left/physiopathology
    Language English
    Publishing date 2016-12
    Publishing country United States
    Document type Journal Article ; Observational Study
    ZDB-ID 82046-5
    ISSN 1873-2623 ; 0041-1345
    ISSN (online) 1873-2623
    ISSN 0041-1345
    DOI 10.1016/j.transproceed.2016.08.049
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: The distance effects of environmental variables on older African American women's physical activity in Texas

    Shin, W.-H. / Kweon, B.-S. / Shin, W.-J.

    Landscape and urban planning

    2011  Volume 103, Issue 2, Page(s) 217

    Language English
    Document type Article
    ZDB-ID 742504-1
    ISSN 0169-2046
    Database Current Contents Nutrition, Environment, Agriculture

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  7. Article ; Online: Polypoidal choroidal vasculopathy and late geographic hyperfluorescence on indocyanine green angiography.

    Kang, S W / Chung, S E / Shin, W J / Lee, J-H

    The British journal of ophthalmology

    2009  Volume 93, Issue 6, Page(s) 759–764

    Abstract: Background/aims: To report the clinical significance of late geographic hyperfluorescence (LGH) on indocyanine green angiography (ICGA) in cases of polypoidal choroidal vasculopathy (PCV).: Methods: The medical records of 43 eyes with PCV, all of ... ...

    Abstract Background/aims: To report the clinical significance of late geographic hyperfluorescence (LGH) on indocyanine green angiography (ICGA) in cases of polypoidal choroidal vasculopathy (PCV).
    Methods: The medical records of 43 eyes with PCV, all of which had undergone at least 12 months of follow-up, 40 eyes with exudative age-related macular degeneration (AMD) and 20 eyes of age-matched normal subjects were retrospectively analysed. The incidence of LGH, defined as a well-demarcated geographic hyperfluorescent lesion on late phase ICGA, was compared in each respective group. The natural course of the LGH and its changes after photodynamic therapy (PDT) were analysed.
    Results: LGH was noted in all of the eyes with PCV, whereas LGH was noted in three eyes (7.5%) of the eyes with exudative AMD and was not noted in any of the normal subjects (p<0.01). Of the 27 eyes (62.8%) with PCV, LGH was matched to the total area of the branching vascular network and polyps. The extent of LGH was enlarged over time in approximately one-half of the cases. As compared with the eyes demonstrating persistent LGH after PDT, the eyes with fading or disappearing LGH evidenced a lower recurrence of active PCV (p<0.05).
    Conclusion: LGH is a highly sensitive and specific ICGA finding for the diagnosis of PCV. Increased surveillance should be implemented in eyes in which LGH persists after PDT.
    MeSH term(s) Adult ; Aged ; Aged, 80 and over ; Choroid/blood supply ; Choroid Diseases/diagnosis ; Choroid Diseases/drug therapy ; Choroidal Neovascularization/diagnosis ; Choroidal Neovascularization/drug therapy ; Coloring Agents ; Diagnosis, Differential ; Female ; Fluorescein Angiography/methods ; Humans ; Indocyanine Green ; Macular Degeneration/diagnosis ; Male ; Middle Aged ; Photochemotherapy ; Polyps/diagnosis ; Polyps/drug therapy ; Recurrence ; Retrospective Studies ; Treatment Outcome
    Chemical Substances Coloring Agents ; Indocyanine Green (IX6J1063HV)
    Language English
    Publishing date 2009-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 80078-8
    ISSN 1468-2079 ; 0007-1161
    ISSN (online) 1468-2079
    ISSN 0007-1161
    DOI 10.1136/bjo.2008.145862
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Does stroke volume variation predict intraoperative blood loss in living right donor hepatectomy?

    Kim, Y K / Shin, W J / Song, J G / Jun, I G / Hwang, G S

    Transplantation proceedings

    2011  Volume 43, Issue 5, Page(s) 1407–1411

    Abstract: Background: Although stroke volume variation (SVV) is a valuable index of preload responsiveness, there is limited information about the association between low SVV and increased hepatectomy-related bleeding. We therefore evaluated whether SVV predicts ... ...

    Abstract Background: Although stroke volume variation (SVV) is a valuable index of preload responsiveness, there is limited information about the association between low SVV and increased hepatectomy-related bleeding. We therefore evaluated whether SVV predicts blood loss during living donor hepatectomy.
    Methods: We evaluated 93 adult liver donors undergoing right hepatectomy for transplantation. Arterial blood pressure, heart rate, body temperature, central venous pressure, SVV, cardiac output, and systemic vascular resistance were measured. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to determine independent factors and optimal cutoff values of hemodynamic parameters for predicting intraoperative blood loss ≥ 700 mL.
    Results: Of these 93 donors, 36 (38.7%) had blood loss ≥ 700 mL. Univariate logistic regression analysis showed that factors associated with blood loss ≥ 700 mL included heart rate, SVV, cardiac output, and systemic vascular resistance. Multivariate logistic regression analysis revealed that only SVV was an independent predictor of blood loss ≥ 700 mL. ROC curve analysis showed that the optimal cutoff value for SVV predicting blood loss ≥ 700 mL was 6% (area under the curve = 0.64).
    Conclusions: SVV is a significant independent predictor of blood loss ≥ 700 mL during donor hepatectomy, suggesting that low SVV may provide useful information on intraoperative bleeding in donors undergoing right hepatectomy.
    MeSH term(s) Adult ; Blood Loss, Surgical ; Blood Pressure ; Body Temperature ; Female ; Heart Rate ; Humans ; Liver Transplantation ; Living Donors ; Male ; ROC Curve ; Stroke Volume
    Language English
    Publishing date 2011-06
    Publishing country United States
    Document type Journal Article
    ZDB-ID 82046-5
    ISSN 1873-2623 ; 0041-1345
    ISSN (online) 1873-2623
    ISSN 0041-1345
    DOI 10.1016/j.transproceed.2011.02.056
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Book ; Online: Dissolved inorganic carbon export from carbonate and silicate catchments estimated from carbonate chemistry and δ13CDIC

    Shin, W. J. / Chung, G. S. / Lee, D. / Lee, K. S.

    eISSN: 1607-7938

    2011  

    Abstract: This work presents a study of the dissolved inorganic carbon (DIC) exchange associated with groundwater discharge and stream flow from two upstream catchments with distinct basement lithologies (silicate vs. carbonate). The effects of catchment lithology ...

    Abstract This work presents a study of the dissolved inorganic carbon (DIC) exchange associated with groundwater discharge and stream flow from two upstream catchments with distinct basement lithologies (silicate vs. carbonate). The effects of catchment lithology were evident in the spring waters showing lower δ 13 C DIC and alkalinity (−16.2 ± 2.7 ‰ and 0.09 ± 0.03 meq l −1 , respectively) in the silicate and higher values (−9.7 ± 1.5 ‰ and 2.0 ± 0.2 meq l −1 ) in the carbonate catchment. The streams exhibited relatively high δ 13 C DIC , −6.9 ± 1.6 ‰ and −7.8 ± 1.5 ‰, in silicate and carbonate catchments, respectively, indicating CO 2 degassing during groundwater discharge and stream flow. The catchment lithology affected the pattern of DIC export. The CO 2 degassing from stream and groundwater could be responsible for 8–55 % of the total DIC export in the silicate catchment, whereas the proportion is comparatively low (0.4–5.6 %) in the carbonate catchment. Therefore, the dynamic carbon exchange occurring at headwater regions and its possible variability with catchment lithology need to be examined for a more reliable carbon budget in river systems.
    Subject code 333 ; 550
    Language English
    Publishing date 2011-08-16
    Publishing country de
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Factors affecting intraoperative changes in regional cerebral oxygen saturation in patients undergoing liver transplantation.

    Jun, I-G / Shin, W-J / Park, Y-S / Song, J-G / Kim, Y-K / Hwang, G-S

    Transplantation proceedings

    2013  Volume 45, Issue 1, Page(s) 245–250

    Abstract: Background: Regional oxygen saturation (rSO(2)) is a sensitive marker of cerebral hypoperfusion during liver transplantation. However, bilirubin absorbs near-infrared light, resulting in falsely low rSO(2) values. We sought to determine whether rSO(2) ... ...

    Abstract Background: Regional oxygen saturation (rSO(2)) is a sensitive marker of cerebral hypoperfusion during liver transplantation. However, bilirubin absorbs near-infrared light, resulting in falsely low rSO(2) values. We sought to determine whether rSO(2) values vary in response to bilirubin concentrations during liver transplantation and to assess whether rSO(2) changes were associated with factors reflecting cerebral oxygen delivery in patients with hyperbilirubinemia.
    Methods: Measurements of rSO(2) values continuous cardiac output (CO), mean arterial pressure, central venous pressure, body temperature, arterial blood gas analysis, and laboratory parameters were simultaneously performed at 1 hour after the surgical incision (baseline) and at 3 predetermined times during the anhepatic and neohepatic phases in 95 end-stage liver disease patients including 67 males of Child A/B/C/29/29/37 categories respectively. Relationships between changes in parameters were evaluated by correlation and multivariate regression analyses.
    Results: The 273 measurements revealed changes in rSO(2) (range, -18% to 40%) to correlate significantly with alterations in hemoglobin (Hb), serum glucose, lactate, prothrombin time, pH, partial arterial CO(2) pressure (PaCO(2)), and CO, but not with serum total bilirubin (TB). Multivariate linear regression analysis revealed that changes in Hb, CO, PaCO(2), and pH were independent of rSO(2) changes during liver transplantation.
    Conclusions: Our findings showed that rSO(2) changes were independently associated with factors reflecting cerebral oxygen delivery, such as Hb, CO, PaCO(2), and pH, whereas rSO(2) values did not correlate with changes in bilirubin concentrations, indicating that rSO(2) changes reveal cerebral oxygen balance regardless of TB levels among patients undergoing liver transplantation.
    MeSH term(s) Adult ; Aged ; Cardiac Output ; Cerebrovascular Circulation/physiology ; Female ; Humans ; Hydrogen-Ion Concentration ; Hyperbilirubinemia/metabolism ; Liver Failure/surgery ; Liver Transplantation/methods ; Magnetic Resonance Angiography ; Male ; Medical Records Systems, Computerized ; Middle Aged ; Oxygen/metabolism ; Perfusion ; Regression Analysis ; Spectroscopy, Near-Infrared
    Chemical Substances Oxygen (S88TT14065)
    Language English
    Publishing date 2013-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 82046-5
    ISSN 1873-2623 ; 0041-1345
    ISSN (online) 1873-2623
    ISSN 0041-1345
    DOI 10.1016/j.transproceed.2012.10.025
    Database MEDical Literature Analysis and Retrieval System OnLINE

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