Ternary Oxides in the TiO2-ZnO System as Efficient Electron-Transport Layers for Perovskite Solar Cells with Efficiency over 15.

Perovskite solar cells, which utilize organometal-halide perovskites as light-harvesting materials, have attracted great attention due to their high power conversion efficiency (PCE) and potentially low cost in fabrication. A compact layer of TiO2 or ZnO is generally applied as electron-transport layer (ETL) in a typical perovskite solar cell. In this study, we explored ternary oxides in the TiO2-ZnO system to find new materials for the ETL. Compact layers of titanium zinc oxides were readily prepared on the conducting substrate via spray pyrolysis method. The optical band gap, valence band maximum and conduction band minimum of the ternary oxides varied significantly with the ratio of Ti to Zn, surprisingly, in a nonmonotonic way. When a zinc-rich ternary oxide was applied as ETL for the device, a PCE of 15.10% was achieved, comparable to that of the device using conventional TiO2 ETL. Interestingly, the perovskite layer deposited on the zinc-rich ternary oxide is stable, in sharp contrast with that fabricated on a ZnO layer, which will turn into PbI2 readily when heated. These results indicate that potentially new materials with better performance can be found for ETL of perovskite solar cells in ternary oxides, which deserve more exploration.

Up-regulation of VEGF by retinoic acid during hyperoxia prevents retinal neovascularization and retinopathy.

PURPOSE: Retinopathy of prematurity (ROP) is directly associated with abnormal expression of retinal vascular endothelial growth factor (VEGF) in premature neonates. This study was to investigate whether the systemic administration of retinoic acid (RA) regulates retinal VEGF expression and prevents retinal neovascularization and retinopathy in the oxygen-induced retinopathy (OIR) mouse model. METHODS: C57BL/6 mice were subjected to OIR by exposure to 75% oxygen from postnatal day (P) 7 to 12 of age. RA was intraperitoneally injected daily to pups from P6 to P9. Retinal whole mount staining and image analysis, immunostaining, Western blotting, quantitative RT-PCR, TUNEL assay, and electroretinography were performed to evaluate the effects of RA on VEGF expression, retinal neovascularization, and retinal neuron functions. RESULTS: Systemic administration of RA in OIR mice promoted retinal VEGF mRNA and protein expression in phase I; the stabilized level of VEGF in phase I supported retinal vascular development and counteracted vaso-obliteration in OIR mice. Subsequently, the excessive generation of VEGF in phase II was attenuated; the retinal vascular leakage and apoptotic cells were significantly ameliorated. As a result, RA significantly prevented the development of hypoxia-induced retinal neovascularization and retinopathy in OIR mice and improved the functional recovery of retinal neurons downstream of photoreceptor cells as measured by focal electroretinography. CONCLUSIONS: Systemic administration of RA regulates retinal VEGF expression and supports retinal vascular development in OIR mouse model. We propose that systemic administration of RA to extremely low birth weight, preterm infants during oxygen therapy could potentially be an effective therapeutic approach for the prevention of ROP.

The role of in vivo confocal microscopy in the diagnosis of hidden corneal foreign bodies.

OBJECTIVE: To investigate in vivo confocal microscopy (IVCM) to diagnose hidden corneal foreign bodies. METHODS: Male Kunming mice (n = 25; 12 weeks old) were anaesthetized prior to the insertion of five different materials (spiny wood, rusty iron, sharp stone, sharp glass fragment and human hair fragment) into the cornea by different traumatic processes. A separate mouse was used for each corneal foreign body. The corneas of the mice were scanned 24 h later by a laser scanning IVCM to establish the characteristics (shape, reflectivity and depth in the cornea) of each foreign body. These findings were used to help screen and identify corneal foreign bodies in patients. Corneal smears and scraping cultures were performed in cases of probable corneal infection. RESULTS: Animal models for the five different foreign particles were established successfully, with each showing distinctive characteristics. These animal results were used to diagnose 41 patients with suspected corneal foreign bodies who were negative by slit lamp examination, but positive by IVCM (observational case series). The most prevalent type of hidden foreign body was plant material (51.2%), followed by metal (29.3%). Ten patients with corneal foreign bodies developed fungal keratitis, found using IVCM. CONCLUSIONS: Laser IVCM is an effective and reliable tool for the diagnosis of hidden corneal foreign bodies.

Using bovine pituitary extract to increase proliferation of keratocytes and maintain their phenotype in vitro.

AIM: To investigate the effects of bovine pituitary extract on the proliferation of keratocytes and maintaining the keratocyte phenotype in vitro. METHODS: Single keratocytes were isolated by enzyme digestion for in vitro culture. Three groups were designed according to the different culture media: a bovine pituitary extract (BPE) group, a fetal bovine serum (FBS) group and the control group. The phenotypes and proliferation of cultured cells were evaluated by morphology, immunofluorescent staining and mRNA expression of CD34, Lumican, VSX1, α-SMA and proliferating cell nuclear antigen (PCNA). In the BPE group, cells underwent serial subcultivation, and their phenotypes were identified by immunofluorescent staining. To analyze the proliferation of keratocytes in different concentrations of BPE, six different concentrations were designed to ascertain the most appropriate amount. RESULTS: In the BPE group, the cells spread out and presented dendritic morphology, and their dendrites connected to one another to form networks. On the third passage, most cells maintained their phenotype. In the FBS group, the cells exhibited a dendritic appearance in early cultured stages, but their morphology subsequently changed into a fibroblast-like shape. The number of dendritic cells in BPE group was more than FBS and control groups. Immunofluorescent staining and real-time polymerase chain reaction (PCR) confirmed that few keratocytes underwent fibroblastic transformation in the BPE and control groups, and that proliferation was higher in the BPE group than in the control group. Although the proliferation was higher in the FBS group, many keratocytes underwent fibroblastic transformation. The analysis of cell morphology and mRNA expressions of CD34, PCNA and VSX1 in six group showed that different concentrations of BPE affected the proliferation obviously but didn't affect the keratocyte phenotype, and the concentration of 40µg/mL was the most appropriate one. CONCLUSION: BPE can improve the proliferation of keratocytes and maintain their phenotype in vitro. Many keratocytes can be harvested rapidly and provide seeds for the construction of corneal stroma.