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Transparent Al2O3ceramics with grains aligned to the c-axis were prepared by adding platelets with a low aspect ratio into fine equiaxed particles. The mixed powders were formed into green bodies using spontaneous coagulation casting and sintered by pressureless sintering and hot-isostatic pressure sintering. Zeta potentials and rheological behavior of the slurries, relative densities of green bodies, and orientation and optical properties of sintered bodies were investigated and discussed. The platelet with a high aspect ratio suppressed densification more seriously during sintering than the one with a low aspect ratio. An excellent oriented structure was obtained when 5 wt% platelets with a low aspect ratio were added, and transparent Al2O3ceramics with grains aligned to c-axis were successfully prepared; the in-line transmittance was 78.4% at 600 nm, which is the highest one in the currently reported literature.

BACKGROUND:: Corneal disease is second only to cataract considered as the leading cause of blindness in the world, with high morbidity. Construction of corneal substitutesin vitroby tissue engineering technology to achieve corneal regeneration has become a research hotspot in recent years. We conducted in-depth research on the biocompatibility, physicochemical and mechanical properties of rat bone marrow mesenchymal stem cells (rBM-MSCs)-seeded gelatin methacrylate (GelMA) as a bioengineered cornea. METHODS:: Four kinds of GelMA with different concentrations (7, 10, 15 and 30%) were prepared, and their physic-chemical, optical properties, and biocompatibility with rBM-MSCs were characterized. MTT, live/dead staining, cell morphology, immunofluorescence staining and gene expression of keratocyte markers were performed. RESULTS:: 7%GelMA hydrogel had higher equilibrium water content and porosity, better optical properties and hydrophilicity. In addition, it is more beneficial to the growth and proliferation of rBM-MSCs. However, the 30%GelMA hydrogel had the best mechanical properties, and could be more conducive to promote the differentiation of rBM-MSCs into keratocyte-like cells. CONCLUSION:: As a natural biological scaffold, GelMA hydrogel has good biocompatibility. And it has the ability to promote the differentiation of rBM-MSCs into keratocyte-like cells, which laid a theoretical and experimental foundation for further tissue-engineered corneal stromal transplantation, and provided a new idea for the source of seeded cells in corneal tissue engineering.

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The A2B2O7series of ternary oxides are derivatives of fluorite structure over a wide range of rA/rB. Competing by two rare-earths the A-site, La2-xLuxZr2O7ceramics were found transparent only in pore-free microstructures with similar grain sizes of pyrochlore (PY) and defective fluorite (DF) phases. Mutual solubilities of Lu and La in both phases were found by imaging and energy-dispersive spectroscopy analysis in scanning electron microscope. The dual-phase microstructures were developed with liquid-phase resulted from the exothermal reactions, creating a miscibility gap between two structures to moderate their competing grain growth. Change in grain growth behaviors in liquid-phase is described by a nucleation line in La2Zr2O7‒Lu2Zr2O7phase diagram. Variations of solution levels in DF grains and co-existing of dual-phase grain clusters in common orientation were revealed in transparent ceramics by electron backscattered diffraction, resulted by epitaxial relation of two phases promoted by the liquid-phase. Oxygen vacancies and various hole states common in both phases were revealed by characteristic cathodoluminescence peaks. The collective effects of pores, phase and grain boundaries, oxygen vacancies on scattering or absorption of visible light enables to establish a hierarchical microstructure‒transparency relationship in such complex oxide ceramics, which could be tailored or further optimized by controllable sintering.

In this study, a terbium(Ш) complex, Tb(SSA)4(SSA = sulfosalicylate), was synthesized and employed to detect toxic chromate anion (CrO42−) as a visually identifiable probe. Luminescence investigations confirmed that the Tb complex is an excellent probe with high selectivity, high sensitivity (I0/I100 μM= 9.5), and a low detection limit (2.8 × 10−8M), targeting CrO42−in aqueous solution. The simple fluorescence‐based probe can be quickly and easily prepared, and enables the reliable, visual detection of CrO42−ion in daily applications.

A2B2O7system compounds, which usually present three phase structures mainly based on the ionic radius ratios of rAand rB(rA/rB), have been studied for potential applications in many fields, such as thermal barrier coatings, luminescence powders, fast-ion conductors, photocatalysts, and matrices for immobilization of highly active radionuclides. Since 2005, La2Hf2O7was fabricated into transparent ceramics and much more attentions were paid on A2B2O7transparent ceramics for new applications. In this review, the development of A2B2O7system transparent ceramics was described. The structure characteristics, powder synthesis method, and sintering techniques of the final A2B2O7transparent ceramics were summarized. After that, the mostly reported A2Hf2O7, A2Zr2O7, and A2Ti2O7system transparent ceramics were systematically introduced. The potential application fields and future development trends were also discussed, focusing on scintillators, optical elements, and other luminescent materials

To quantify the oxygen content in molten salts, we examined the performance of an yttria-stabilized zirconia solid electrolyte oxygen sensor with a Bi/Bi2O3reference electrode, focusing on its output accuracy. When the above sensor was tested in a flow of gas with known oxygen partial pressure, $$p_{O_2}$$pO2, a linear relationship between $$lgp_{O_2}$$lgpO2and the electromotive force (EMF) was observed, and the correlation slope exhibited a positive deviation from Nernstian behavior. EMF measurements performed in molten NaCl–KCl indicated that the oxygen content of this salt mixture increased with increasing oxygen partial pressure in the covering gas, in agreement with Henry’s law. Moreover, the EMF exhibited a linear decrease with increasing melt temperature of molten NaCl–KCl, in agreement with the theoretical model. Finally, a relationship between the structure of molten NaCl–KCl and its oxygen diffusion behavior was established. As a result, the developed sensor was demonstrated to be well suited for determining the oxygen content of molten salts.

Aluminum nitride ceramic sheets were formed for the first time by a novel and simple method, namely gel-tape-casting process, where only two additives were used to prepare the slurries. PIBM (a water-soluble copolymer of isobutylene and maleic anhydride) acted as both dispersant and gelling agent, and PEG (polyethylene glycol) acted as plasticizer. Combining the advantages of gel-casting and tape-casting processes, flexible and uniform green tapes were obtained. The rheological properties of AlN slurries were studied to optimize the PIBM content and solids loading. After drying and debinding, the green sheets were sintered at 1840 °C in N2atmosphere. Homogeneous microstructure with average grain size of about 7 μm was observed in the final AlN ceramics. Thermal conductivity of the AlN ceramics was 161 W/(m·K).

To evaluate the optical coherence tomography (OCT) angiography features in patients with idiopathic macular hole (IMH) before and after vitrectomy.This prospective study included 25 patients diagnosed with IMH in Shanxi eye hospital from August 2019 to December 2021. The study was divided into 3 groups: IMH eyes, fellow eyes and normal eyes. All unilateral IMH eyes underwent vitrectomy.There were significant differences in superficial retinal blood flow density (SRBFD, P< .001) and choroidal blood flow density (CBFD) between IMH and healthy control eyes before operation (P< .05). There was significant difference in SRBFD between fellow eyes and normal eyes (P= .038). The changes of SRBFD and CBFD in IMH eyes before and after operation were statistically significant (P< .05). The CBFD at 6 months after operation is negatively correlated with LogMAR visual acuity, and the CBFD of the fellow eye is also negatively correlated with LogMAR visual acuity. The SRBFD and CBFD had no correlation with the diameter of macular hole before and after operation.SRBFD and CBFD increased after vitrectomy, indicating that the blood supply of retina and choroid were partially restored after vitrectomy. There was no correlation between SRBFD, CBFD and hole diameter, but there was correlation between choroidal blood flow and LogMAR visual acuity.

Poyang Lake is one of the first Ramsar sites in China; it has plenty of natural resources that support the survival of local residents. However, local fisherman have encountered a livelihood dilemma, as natural resources have declined, obviously because of the change in the ecological environment and anthropic disturbance. We seek to explain what lead to livelihood dilemma to the local fishermen, so semi-structured interviews, questionnaire surveys, Geographic information system (GIS), Remote sensing (RS), Global position system (GPS), and department data were used to analyze the internal and external factors for these dilemmas. The results explained the external factors including the exhaustion of natural resources, the drying up of wetlands, landscape fragmentation, water contamination, and disturbance through anthropic behavior; the internal factors included the ageing of fishermen, poor cultural quality, conservative ideas, and unreasonable fishing practices. Eco-compensation, industry transformation, and capacity innovation may help to resolve livelihood dilemmas for the local fisherman of the Poyang Lake wetlands.