Rapid Hydrothermal Synthesis of Zinc Oxide Nanowires by Annealing Methods on Seed Layers

Well-aligned zinc oxide (ZnO) nanowire arrays were successfully synthesized on a glass substrate using the rapid microwave heating process. The ZnO seed layers were produced by spinning the precursor solutions onto the substrate. Among coatings, the ZnO seed layers were annealed at 100°C for 5 minutes to ensure particle adhesion to the glass surface in air, nitrogen, and vacuum atmospheres. The annealing treatment of the ZnO seed layer was most important for achieving the high quality of ZnO nanowire arrays as ZnO seed nanoparticles of larger than 30 nm in diameter evolve into ZnO nanowire arrays. Transmission electron microscopy analysis revealed a single-crystalline lattice of the ZnO nanowires. Because of their low power (140 W), low operating temperatures (90°C), easy fabrication (variable microwave sintering system), and low cost (90% cost reduction compared with gas condensation methods), high quality ZnO nanowires created with the rapid microwave heating process show great promise for use in flexible solar cells and flexible display devices

Theoretical Estimation of Cannulation Methods for Left Ventricular Assist Device Support as a Bridge to Recovery

Left ventricular assist device (LVAD) support under cannulation connected from the left atrium to the aorta (LA-AA) is used as a bridge to recovery in heart failure patients because it is non-invasive to ventricular muscle. However, it has serious problems, such as valve stenosis and blood thrombosis due to the low ejection fraction of the ventricle. We theoretically estimated the effect of the in-series cannulation, connected from ascending aorta to descending aorta (AA-DA), on ventricular unloading as an alternative to the LA-AA method. We developed a theoretical model of a LVAD-implanted cardiovascular system that included coronary circulation. Using this model, we compared hemodynamic responses according to various cannulation methods such as LA-AA, AA-DA, and a cannulation connected from the left ventricle to ascending aorta (LV-AA), under continuous and pulsatile LVAD supports. The AA-DA method provided 14% and 18% less left ventricular peak pressure than the LA-AA method under continuous and pulsatile LVAD conditions, respectively. The LA-AA method demonstrated higher coronary flow than AA-DA method. Therefore, the LA-AA method is more advantageous in increasing ventricular unloading whereas the AA-DA method is a better choice to increase coronary perfusion

Transjugular insertion of biliary stent in patients with malignant biliary obstruction complicated by ascites with/without coagulopathy: a prospective study of 12 patients

PURPOSEIn patients with malignant biliary obstruction complicated by massive ascites, when endoscopy fails, safe routes for biliary decompression are needed as an alternative to percutaneous approach. We aimed to evaluate the safety and effectiveness of transjugular insertion of biliary stent (TIBS) in patients with malignant biliary obstruction complicated by massive ascites with or without coagulopathy.METHODSFrom March 2012 to December 2017, a total of 12 consecutive patients with malignant biliary obstructions treated with TIBS were enrolled in this study. Five patients had jaundice and cholangitis, while seven had jaundice only. Clinical parameters including technical and clinical success rates and complications following TIBS were evaluated. Overall survival and stent occlusion-free survival were assessed using Kaplan-Meier analysis.RESULTSThe indications for transjugular approach were massive ascites with (n=2) or without (n=10) coagulopathy. TIBS was technically successful in 11 of 12 patients. Clinical success was defined as successful internal drainage and was achieved in eight patients. The mean serum bilirubin level was initially 13.9±6.3 mg/dL and decreased to 4.9±5.3 mg/dL within 1 month after stent placement (P = 0.037). Two patients had procedure-related complications (hemobilia). During the follow-up period (mean, 30 days; range, 1–146 days), all 12 patients died of disease progression. The median overall survival and stent occlusion-free survival times were 19 days (95% confidence interval [CI], 16–22 days) and 19 days (95% CI, 12–26 days), respectively. There was no stent dysfunction in the eight patients that had successful internal drainage.CONCLUSIONTIBS appears to be safe, technically feasible, and clinically effective for patients with malignant biliary obstruction complicated by massive ascites with or without coagulopathy

Prediction of Plaque Progression in Coronary Arteries Based on a Novel Hemodynamic Index Calculated From Virtual Stenosis Method

RationalePredicting the sites in coronary arteries that are susceptible to plaque deposition is essential for the development of clinical treatment strategies and prevention. However, to date, no physiological biomarkers for this purpose have been developed. We hypothesized that the possibility of plaque deposition at a specific site in the coronary artery is associated with wall shear stress (WSS) and fractional flow reserve (FFR).Background and ObjectiveWe proposed a new biomarker called the stenosis susceptibility index (SSI) using the FFR and WSS derived using virtual stenosis method. To validate the clinical efficacy of this index, we applied the method to actual pilot clinical cases. This index non-invasively quantifies the vasodilation effects of vascular endothelial cells relative to FFR variation at a specific coronary artery site.Methods and ResultsUsing virtual stenosis method, we computed maximum WSS and FFR according to the variation in stenotic severity at each potential stenotic site and then plotted the variations of maximum WSS (y-axis) and FFR (x-axis). The slope of the graph indicated a site-specific SSI value. Then we determined the most susceptible sites for plaque deposition by comparing SSI values between the potential sites. Applying this method to seven patients revealed 71.4% in per-patient basis analysis 77.8% accuracy in per-vessel basis analysis in percutaneous coronary intervention (PCI) site prediction.ConclusionThe SSI index can be used as a predictive biomarker to identify plaque deposition sites. Patients with relatively smaller SSI values also had a higher tendency for myocardial infarction. In conclusion, sites susceptible to plaque deposition can be identified using the SSI index

Isolated Left Ventricular Noncompaction Cardiomyopathy Accompanied by Severe Mitral Regurgitation

Isolated left ventricular noncompaction cardiomyopathy (IVNC) is a cardiomyopathy thought to be caused by arrest of normal embryogenesis of the endocardium and myocardium. This abnormality is often associated with other congenital cardiac defects. A 21-year-old man presented to the emergency department with worsening exertional dyspnea during the previous 2 months. Two-dimensional and Doppler echocardiography revealed an enlarged left atrium (LA) and a markedly dilated left ventricle (LV) with preserved LV systolic function, severe mitral valve regurgitation, and prolapse due to chordae rupture. The myocardium of the LV and right ventricle (RV) had excessively prominent trabeculations and deep intertrabecular recesses. He is the first patient in Korea who has undergone mitral valve replacement surgery because of severe mitral valve regurgitation and prolapse due to chordae rupture accompanied by IVNC

Interlayer orientation-dependent light absorption and emission in monolayer semiconductor stacks

Two-dimensional stacks of dissimilar hexagonal monolayers exhibit unusual electronic, photonic and photovoltaic responses that arise from substantial interlayer excitations. Interband excitation phenomena in individual hexagonal monolayer occur in states at band edges (valleys) in the hexagonal momentum space; therefore, low-energy interlayer excitation in the hexagonal monolayer stacks can be directed by the two-dimensional rotational degree of each monolayer crystal. However, this rotation-dependent excitation is largely unknown, due to lack in control over the relative monolayer rotations, thereby leading to momentum-mismatched interlayer excitations. Here, we report that light absorption and emission in MoS2/WS2 monolayer stacks can be tunable from indirect- to direct-gap transitions in both spectral and dynamic characteristics, when the constituent monolayer crystals are coherently stacked without in-plane rotation misfit. Our study suggests that the interlayer rotational attributes determine tunable interlayer excitation as a new set of basis for investigating optical phenomena in a two-dimensional hexagonal monolayer system.open115850sciescopu

Takayasu's Arteritis Treated by Percutaneous Transluminal Angioplasty with Stenting in the Descending Aorta

A 17-yr-old young woman was referred to our hospital with a 2-yr history of claudication of the lower extremities and severe arterial hypertension. Physical examination revealed significantly different blood pressures between both arms (160/92 and 180/95 mmHg) and legs (92/61 and 82/57 mmHg). The hematological and biochemical values were within their normal ranges, except for the increased erythrocyte sedimentation rate (83 mm/hr) and C-reactive protein (6.19 mg/L). On 3-dimensional computed tomographic angiography, the ascending aorta, the aortic arch and its branches, and the thoracic and, descending aorta, but not the renal artery, were shown to be stenotic. The diagnosis of type IIb Takayasu's arteritis was made according to the new angiographic classification of Takayasu's arteritis, Takyasu conference 1994. Percutaneous transluminal angioplasty with stenting was performed on the thoracic and abdominal aorta. After the interventional procedures, the upper extremity blood pressure improved from 162/101 mmHg to 132/85 mmHg, respectively. She has been free of claudication and there have been no cardiac events during 2-yr of clinical follow-up