Microstructure design for blended feedstock and its thermal durability in lanthanum zirconate based thermal barrier coatings

The effects of microstructure design on the lifetime performance of lanthanum zirconate (La2Zr2O7; LZO)-based thermal barrier coatings (TBCs) were investigated through various thermal exposure tests, such as furnace cyclic thermal fatigue, thermal shock, and jet engine thermal shock. To improve the thermal durability of LZO-based TBCs, composite top coats using two feedstock powders of LZO and 8 wt.% yttria-doped stabilized zirconia (8YSZ) were prepared by mixing in different volume ratios (50:50 and 25:75, respectively). In addition, buffer layers were introduced in layered LZO-based TBCs deposited using an air-plasma spray method. The TBC with the double buffer layer showed the best thermal cycle performance among all samples in all tests. For applications with relatively slow cooling rates, the thermal durability in single-layer TBCs is more effectively enhanced by controlling a composition ratio in the blended powder, better than introducing a single buffer layer. For applications with relatively fast cooling rates, the thermal durability can be effectively improved by introducing a buffer layer than controlling a composition in the top coat, since the buffer layer provides fast localized stress relief due to its high strain compliance. These research findings allow us to control the TBC structure, and the buffer layer is efficient in improving thermal durability in cyclic thermal environments

Cell density-dependent differential proliferation of neural stem cells on omnidirectional nanopore-arrayed surface

112Ysciescopu

A standardized extract of Rhynchosia volubilis Lour. exerts a protective effect on benzalkonium chloride-induced mouse dry eye model

ETHNOPHARMACOLOGICAL RELEVANCE In contrast to other leguminous plants generally used as food, Rhynchosia volubilis Loureiro, a small soybean with a black seed coat, has been used as a traditional oriental remedy for various human diseases in Eastern Asia. In this study, we demonstrated the protective effect of R. volubilis against dry eye disease. AIM OF THE STUDY We aimed to investigate whether a standardized ethanol extract of R. volubilis (EERV) can protect the cornea in a benzalkonium chloride (BAC)-induced mouse dry eye model. MATERIALS AND METHODS Experimental dry eye was induced by the instillation of 0.2% BAC on mouse cornea. A standardized ethanol extract of R. volubilis (EERV) was orally administered following BAC treatment. The positive control group was treated with commercial eye drops. Fluorescein staining, tear break-up time (BUT), and hematoxylin and eosin staining were evaluated on the ocular surface. Squamous metaplasia and apoptosis in the corneal epithelial layer were detected by immunostaining. Furthermore, the protein expression of cytochrome c, Bcl-2, and Bax was determined. RESULTS EERV treatment significantly improved fluorescein scoring, BUT, and smoothness in the cornea compared to the vehicle group. In addition, EERV inhibited squamous metaplasia and apoptosis in the cornea. The expression of cytochrome c and Bax was upregulated, while that of Bcl-2 was downregulated in the vehicle group compared with that in the control group. However, EERV treatment inhibited the expression of cytochrome c and Bax, while that of Bcl-2 was improved. CONCLUSION Standardized EERV could be a beneficial candidate for the treatment of dry eye disease

Surgical Outcomes and Post-Operative Changes in Patients with Significant Aortic Stenosis and Severe Left Ventricle Dysfunction

Little is known regarding long-term survival and changes in systolic function following surgery after the occurrence of a severe left ventricular (LV) dysfunction in patients with severe aortic stenosis. Inclusion criteria were an aortic valve area less than 1 cm2 and an LV ejection fraction (EF) less than 35%. Between January 1990 and July 2007, 41 (male: 30) patients were identified. The pre-operative mean EF and mean aortic valve area were 26.7±6.1% and 0.54±0.2 cm2, respectively. Concomitant coronary artery bypass surgery was performed in 8 patients (19.6%). Immediate post-operative echocardiogram showed to be much improved in LV EF (27.2±5.5 vs. 37.4±11.3, P<0.001), LV mass index (244.2±75.3 vs. 217.5±71.6, P=0.006), and diastolic LV internal diameter (62.5±9.3 vs. 55.8±9.6, P<0.001). Post-operative LV changes were mostly complete by 6 months, and were maintained thereafter. There was one in-hospital mortality (2.4%) and 12 late deaths including one patient diagnosed with malignancy in whom LV function was normal. Multivariate analysis showed pre-operative atrial fibrillation and NYHA FC IV to be significant risk factors for cardiac-related death. Aortic valve replacement in patients with significant aortic stenosis and severe LV dysfunction showed acceptable surgical outcomes. Moreover, LV function improved significantly in many patients