No abstract

Bone-marrow-derived human MSCs (mesenchymal stem cells) support repair when administered to animals with TBI (traumatic brain injury) in large part through secreted trophic factors. We directly tested the ability of the culture medium (or secretome) collected from human MSCs under normoxic or hypoxic conditions to protect neurons in a rat model of TBI. Concentrated conditioned medium from cultured human MSCs or control medium was infused through the tail vein of rats subjected to TBI. We have demonstrated that MSCs cultured in hypoxia were superior to those cultured in normoxia in inducing expression of both HGF (hepatocyte growth factor) and VEGF (vascular endothelial growth factor) in the cultured medium. We showed further that rats treated with the secretome from both normoxic- and hypoxic-preconditioned MSCs performed significantly better than the controls in both motor and cognitive functional test. Subsequent post-mortem evaluation of brain damage at the 4-day time point confirmed that both normoxic- and hypoxic-preconditioned MSC secretome-treated rats had significantly greater numbers of newly forming neurons, but significantly less than the controls in brain damaged volume and apoptosis. The TBI rats treated with hypoxic-preconditioned MSC secretome performed significantly better in both motor and cognitive function tests and neurogenesis, and had significantly less brain damage than the TBI rats treated with the normoxic-preconditioned MSC secretome. Collectively, these findings suggest that MSCs secrete bioactive factors, including HGF and VEGF, that stimulate neurogenesis and improve outcomes of TBI in a rat model. Hypoxic preconditioning enhances the secretion of these bioactive factors from the MSCs and the therapeutic potential of the cultured MSC secretome in experimental TBI.

Solution processable planar heterojunction perovskite solar cell is a very promising new technology for low cost renewable energy. One of the most common cell structures is FTO/TiO2/CH3NH3PbI3-xClx/spiro-OMeTAD/Au. The main issues of this type of solar cell are the poor coverage and morphology control of the perovskite CH3NH3PbI3-xClx film on TiO2. For the first time, we demonstrate that the problems can be easily resolved by using a polymer additive in perovskite precursor solution during the film formation process. A 25% increase in power conversion efficiency at a value of 13.2% is achieved by adding 1 wt % of poly(ethylene glycol) in the perovskite layer using a 150 °C processed TiO2 nanoparticle layer. The morphology of this new perovskite was carefully studied by SEM, XRD, and AFM. The results reveal that the additive controls the size and aggregation of perovskite crystals and helps the formation of smooth film over TiO2 completely. Thus, the Voc and Jsc are greatly increased for a high efficiency solar cell. The amount of additive is optimized at 1 wt % due to its insulating characteristics. This research provides a facile way to fabricate a high efficiency perovskite solar cell by the low temperature solution process (<150 °C), which has the advancement of conserving energy over the traditional high temperature sintering TiO2 compact layer device.

We demonstrate high-performance, air-stable, low-temperature processed (≦100 °C) semitransparent (ST) perovskite solar cells (PSCs) by the applications of atomic layer deposition (ALD) technology to deposit ZnO and Al 2 O 3 films as cathode buffer layer (CBL) and encapsulation layer, respectively. The application of ALD ZnO film as CBL in PSCs deliver several remarkable features, including fine tunability of the work function of the electrode, low deposition temperature (80 °C), high charge selectivity, good electron-transporting ability (filed-effect mobility = 16.1 cm 2 V -1 s -1 ), and excellent film coverage. With these desired interfacial properties, the device with opaque Ag electrode delivers high power conversion efficiency (PCE) up to 16.5%, greatly outperforming the device with state-of-the-art CBL ZnO nanoparticles film (10.8%). For ST PSCs employing Ag nanowires as transparent top electrode, a remarkable PCE of 10.8% with a corresponding average visible transmittance (AVT) of 25.5% are demonstrated, which represents the highest PCE ever reported for ST PSCs with similar AVT. More significantly, the insufficient ambient stability of ST device is significantly improved by employing excellent gas-barrier performance of ALD Al 2 O 3 -based encapsulation layer, with an oxygen transmission rate of 1.9×10 -3 cm 3 m -2 day -1 and a water vapor transmittance rate of 9.0×10 -4 g m -2 day -1 .

Purpose – The purpose of this paper is to investigate the influences of natural content, food safety concern, health consciousness, and subjective knowledge on attitudes towards organic food and purchase intentions. Design/methodology/approach – Samples are collected in Taiwan from April to May 2014 with a total of 252 returned effective questionnaires. The data are analyzed by structural equation modeling. Findings – The results show that food safety concern and subjective knowledge have a significantly positive impact on attitudes towards organic food and purchase intentions, and natural content has a significantly positive effect on attitudes towards organic food. Moreover, it also shows that health consciousness and attitudes towards organic food have a significantly positive effect on purchase intentions. This study has found that subjective knowledge of organic food, health consciousness, and food safety concern are important factors impacting organic food purchase intentions. Practical implications – This study provides organic industry to understand the consumer’s demand from the consumers’ perspective and as a basis for the future development of organic food. Originality/value – The study results will provide a reference for the agricultural department of the government and the organic food promotion and education of organic food producers.