Surface Chemistry and Work Function of Irradiated and Nanoscale Thin Films Covered Indium Tin Oxides

In this study, we used UV-ozone Ar sputtering, X-ray photoelectron and ultra-violet photoelectron spectroscopies and sputtering based depositions of RuO2 and Se nano-layers on indium tin oxides (ITOs). We elucidated the effect of Ar sputtering on the composition and chemistry of Sn rich ITO surface. We demonstrated that while a combination of UV-ozone radiation and Ar sputtering removes most of the hydrocarbons responsible for degrading the work function of ITO, it also removes significant amount of the segregated SN at the ITO surface that's responsible for its reasonable work function of 4.7eV. We also demonstrated for the first time that sputtering cleaning ITO surface leads to the reduction of the charge state of Sn from Sn4+ to Sn2+ that adds to the degradation of the work function. For the nano-layers coverage of ITO studies, we evaluated both RuO2 and Se. For RuO2 coated ITO, XPS showed the formation of a Ru-Sn-O ternary oxide. The RuO2 nano-layer reduced the oxidation state of Sn in the Sn-rich surface of ITO from +4 to +2. The best work function obtained for this system is 4.98eV, raising the effective work function of ITO by more than 0.5 eV. For the Se coated ITO studies, a systematic study of the dependence of the effective work function on the thickness of Se overage and its chemistry at the Se/ITO interface was undertaken. XPS showed that Se reacts with Sn at the Sn-rich surface of ITO determined the presence of both negative and positive oxidation state of Se at the Se/ITO interface. The Se also reduced the oxidation state of Sn from Sn4+ to Sn2+ in the Sn-rich ITO surface. The highest effective work function obtained for this system is 5.06eV. A combination of RuO2/Se nanoscale coating of optimally cleaned ITO would be a good alternative for device applications that would provide work function tuning in addition to their potential ability to act as interface stabilizers and a barrier to reaction and inter-diffusion at ITO/active layers interfaces responsible for long term stability of devices and especially organic solar cells and organic light emitting diodes

Effects of caffeoylxanthiazonoside on airway inflammation in an allergic asthma mice model

Purpose: To investigate the inhibitory effects of caffeoylxanthiazonoside (CYT) on airway inflammation in mice and its mechanism of action. Methods: An allergic asthma mice model was established by intraperitoneal injection and aerosol nebulization with ovalbumin (OVA). After treatment with CYT, the blood and bronchoalveolar lavage fluid (BALF) were collected from the mice. The leukocytes were classified and counted with Giemsa solution. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of IgE, and IL-4, IL-5, IL-13 and IFN-γ in the BALF of mice. Lung tissues were obtained from the mice and MUC5AC protein expression was measured by western blot. Results: CYT significantly decreased the serum level of IgE in asthmatic mice. Inflammatory cells in BALF of mice were markedly reduced (p < 0.05) by CYT treatment at varying doses (10, 20, and 40 mg/kg). Treatment with CYT also significantly suppressed the cytokines of IL-4, IL-5 and IL-13 and increased the IFN-γ in the BLAF of OVA-induced allergic asthma mice (p < 0.05). Western blot results indicate that CYT treatment significantly decreased the expression of MUC5AC protein in the lung tissues of asthmatic mice. In addition, no significant effects on the body weight of the mice were found after CYT treatment. Conclusion: Caffeoylxanthiazonoside inhibits airway inflammation in allergic asthma mice by altering Th1/Th2 via re-balancing of related cytokines and downregulation of lung MUC5AC protein expression. Therefore, this compound can potentially be developed for the therapeutic management of inflammation in allergic asthma

Synthesis Of Open-Shell Iron Oxide-Polyelectrolyte-Silica Nanocomposite For Water Treatment Application

A open shell structure of silica-polyelectrolyte-iron oxide nanocomposite is synthesized via layer-by-layer assembly. Here, silica colloid is synthesized by Stöber process and iron oxide nanoparticles (IONPs) is synthesized by co-precipitation method. The successful assembly of silica, polyelectrolyte and IONPs into unified nanocomposite was monitored with dynamic light scattering (DLS) and electrophoretic mobility. The core-shell morphology of the nanocomposite was confirmed under the examination of Transmission Electron Microscope (TEM). The final structure showed good colloidal stability up to 10 hours under the monitoring of DLS. The nanocomposite was more magnetically responsive than the bare IONPs with shorten collection time after their exposure to low magnetic field gradient. The interfacial phenomena, which is the conformation of the particles-polymeric structure was monitored by Quartz Crystal Microbalance with Dissipation (QCM-D). The loosely bound and flexible nature of polyelectrolyte promoted larger IONPs deposited amount compared to the bare silica surface without a pre-adsorbed polyelectrolyte. Increasing the initial IONPs concentration (20 to 500 ppm) suppressed the polyelectrolyte layer, giving rise to a stiffer particles-polymeric structure. By increasing the solution ionic strength (0.1 to 100 mM) within critical coagulation concentration up to 50 mM NaCl (obtained by DLS and Derjaguin-Landau-Verwey-Overbeek theory), the particles-polymeric structure became more flexible, leading to the greater amount of deposited IONPs. The open shell structure of the nanocomposite was varied with different polyelectrolyte hierarchy, nature and architecture. From DLS, QCM-D, TEM and AFM (Atomic Force Microscope), it was observed that the deposition of greater amount of IONPs and pollutants molecules into polymeric network was attributed by: (1) the flexible structure conserved by the single layer rather than multilayers of polyelectrolyte, (2) the more extended structure constructed by higher molecular weight than the lower molecular weight of polyelectrolyte, and (3) the branched chain compared to linear chain of polyelectrolyte. Mean field and scaling approximations showed that the protruding side chains of branched PEI contributed to the thicker adsorbed layer (16.14 nm) with more ramified structure compared to linear PDDA (0.19 nm). By taking cationic Methylene Blue, anionic Methyl Orange dyes and Amoxicillin antibiotic as the model system, the performance of nanocomposite can be compared with the silica, silica-polyelectrolyte and bare IONPs. With the ability to facilitate Fenton and Fenton-like reaction with the presence of hydrogen peroxide, nanocomposite achieved highest pollutant removal efficiency among the synthesized nanoparticles. The easiness of magnetic recollection enabled nanocomposite to be recycled for subsequent pollutant removal runs. Nanocomposite retained high pollutant removal efficiency for total 5 recycled runs without significant dissolution of the IONPs from the nanocomposite. The pollutant removal process by nanocomposite can be well illustrated using Langmuir isotherm and pseudo-second-order kinetic model

The Determinants of Knowledge Sharing Intention in Professional Virtual Communities: An Integrative Model

The growing use of information technology and the Internet has led to the emergence of professional virtual communities (PVCs). Why are PVC members willing to spend time and energy to provide valuable knowledge to others? This study extended Icek Ajzen’s(1991) theory of planned behavior (TPB) to analyze what determines PVC members’ willingness to share knowledge. Empirical data were collected from three IT-related PVCs in Taiwan, and the structural equation modeling (SEM) was performed to verify the fit of the proposed model. Based on 423 usable samples were obtained, the results showed that knowledge sharing intentions would be significantly affected by, in order of importance, attitude toward knowledge sharing, perceived behavioral control of knowledge sharing, and subjective norm of knowledge sharing. The factors affecting attitude toward knowledge sharing were, in order of importance, perceived ease of use, perceived usefulness, enjoyment in helping others, knowledge self-efficacy, compatibility, and trust. The major factor that affected the subject norm of knowledge sharing was peer influence. Factors that affected perceived behavioral control of knowledge sharing were, in order of importance, knowledge self-efficacy, resource availability, and perceived ease of use

The inter-comparison of AATSR aerosol optical depth retrievals from various algorithms

The project aerosol-CCI as part of European Space Agency (ESA) Climate Change Initiative (CCI) has provided three aerosol retrieval algorithms for the Advanced Along-Track Scanning Radiometer (AATSR) aboard on ENVISAT. For the purpose of estimating different performance of these three algorithms in Asia, in this paper we compared the Aerosol Optical Depth (AOD) of L2 data (10km×10km) including FMI AATSR Dual-view ADV algorithm, the Oxford RAL Aerosol and Cloud retrieval (ORAC) algorithm and the Swansea University AATSR retrieval (SU) algorithm with the AErosol RObotic NETwork (AERONET) and the China Aerosol Remote Sensing Network (CARSNET) data separately. The result shows that the algorithms of ADV and SU have good performance on the retrieval of AOD, and the ORAC algorithm has relative lower precision than other two algorithms

Harmine Ameliorates Cognitive Impairment by Inhibiting NLRP3 Inflammasome Activation and Enhancing the BDNF/TrkB Signaling Pathway in STZ-Induced Diabetic Rats

Diabetes mellitus (DM) is considered a risk factor for cognitive dysfunction. Harmine not only effectively improves the symptoms of DM but also provides neuroprotective effects in central nervous system diseases. However, whether harmine has an effect on diabetes-induced cognitive dysfunction and the underlying mechanisms remain unknown. In this study, the learning and memory abilities of rats were evaluated by the Morris water maze test. Changes in the nucleotide-binding oligomerization domain-containing protein (NOD)-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome and brain-derived neurotrophic factor (BDNF)/TrkB signaling pathway were determined in both streptozotocin (STZ)-induced diabetic rats and high glucose (HG)-treated SH-SY5Y cells by western blotting and histochemistry. Herein, we found that harmine administration significantly ameliorated learning and memory impairment in diabetic rats. Further study showed that harmine inhibited NLRP3 inflammasome activation, as demonstrated by reduced NLRP3, ASC, cleaved caspase-1, IL-1β, and IL-18 levels, in the cortex of harmine-treated rats with DM. Harmine was observed to have similar beneficial effects in HG-treated neuronal cells. Moreover, we found that harmine treatment enhanced BDNF and phosphorylated TrkB levels in both the cortex of STZ-induced diabetic rats and HG-treated cells. These data indicate that harmine mitigates cognitive impairment by inhibiting NLRP3 inflammasome activation and enhancing the BDNF/TrkB signaling pathway. Thus, our findings suggest that harmine is a potential therapeutic drug for diabetes-induced cognitive dysfunction