19672 research outputs found
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Advanced glycation end products-related modulation of cathepsin L and NF-κB signalling effectors in retinal pigment epithelium lead to augmented response to TNFα
No full textThe retinal pigment epithelium (RPE) plays a central role in neuroretinal homoeostasis throughout life. Altered proteolysis and inflammatory processes involving RPE contribute to the pathophysiology of age-related macular degeneration (AMD), but the link between these remains elusive. We report for the first time the effect of advanced glycation end products (AGE)—known to accumulate on the ageing RPE's underlying Bruch's membrane in situ—on both key lysosomal cathepsins and NF-κB signalling in RPE. Cathepsin L activity and NF-κB effector levels decreased significantly following 2-week AGE exposure. Chemical cathepsin L inhibition also decreased total p65 protein levels, indicating that AGE-related change of NF-κB effectors in RPE cells may be modulated by cathepsin L. However, upon TNFα stimulation, AGE-exposed cells had significantly higher ratio of phospho-p65(Ser536)/total p65 compared to non-AGEd controls, with an even higher fold increase than in the presence of cathepsin L inhibition alone. Increased proportion of active p65 indicates an AGE-related activation of NF-κB signalling in a higher proportion of cells and/or an enhanced response to TNFα. Thus, NF-κB signalling modulation in the AGEd environment, partially regulated via cathepsin L, is employed by RPE cells as a protective (para-inflammatory) mechanism but renders them more responsive to pro-inflammatory stimuli
Board independence, state ownership and stock return volatility during Chinese state enterprise reform
No full textPurpose: This study aimed at investigating the influence of corporate governance on firm risk during the Chinese state enterprise reform. The purposes of this study are to examine the effects of board independence, state ownership and other governance variables on firm risk and to check the influence of controlling shareholder types on firm risk. Design/methodology/approach: This study uses the dynamic and static panel model to estimate the effects of board independence, state ownership and other governance factors on return volatility. To examine the influence of controlling shareholder types on corporate risk-taking, this study further used the treatment effect model (or sample selection model) to analyze the effect of private, state-owned enterprise (SOE) entity, central government and local government controls on corporate risk-taking. Findings: It was found that the enforcement of board independence significantly increases firm risk. The strategy of decentralizing state enterprises (from central government to local government) is a good way to achieve stable stock returns. Originality value: This study contributes to existing knowledge in several ways. First, it focused on independent directors rather than on the size of the corporate board. Second, it highlighted the impacts of state ownership and control on corporate risk. Instead of treating all types of state ownership as homogenous, SOEs are further classified into directly controlled and indirectly controlled, in line with prior studies
Sera of patients with systemic lupus erythematosus cross-neutralizes dengue viruses
No full textDengue is the most prevalent mosquito-borne disease in Southeast Asia, where the incidence of systemic lupus erythematosus (SLE) is approximately 30 to 53 per 100,000. Severe dengue, however, is rarely reported among individuals with SLE. Here, whether sera of patients with SLE cross-neutralize dengue virus (DENV) was investigated. Serum samples were obtained from individuals with SLE who were dengue IgG and IgM serology negative. Neutralization assays were performed against the three major DENV serotypes. Of the dengue serology negative sera of individuals with SLE, 60%, 61% and 52% of the sera at 1/320 dilution showed more than 50% inhibition against dengue type-1 virus (DENV-1), DENV-2 and DENV-3, respectively. The neutralizing capacity of the sera was significantly greater against DENV-1 (P < 0.001) and DENV-3 (P < 0.01) than against DENV-2 (P < 0.05). Neutralization against the DENV correlated with dengue-specific IgG serum titers below the cut-off point for dengue positivity. Depletion of total IgG from the sera of patients with SLE resulted in significant decreases of up to 80% in DENV inhibition, suggesting that IgG plays an important role. However, some of the SLE sera was still able to neutralize DENV, even with IgG titers <0.1 OD absorbance. Our findings suggest that sera of patients with SLE contain IgG, and possibly other type of antibodies, that can cross-neutralize DENV, which may explain the rarity of severe dengue in individuals with SLE. Further studies, are needed to further substantiate this finding and to elucidate the specific neutralizing epitopes recognized by the sera of individuals with SLE
Studies of Ag/TiO2 plasmonics structures integrated in side polished optical fiber used as humidity sensor
No full textIn this report, we investigate the effects of Ag/TiO2 integrated in side polished optical fiber. Several layers of Ag thickness has been deposited on glass substrates using electron beam (e-beam) evaporation technique in order to determinate the influence of silver with combination of TiO2 on final properties of the sensor. Several thicknesses of Ag NPs were sets to 5 nm, 7 nm, 12 nm, and 16 nm. Another layer of metal oxide, specifically titanium oxide (TiO2) is introduced, covering the Ag layer to study the effect of metal oxides toward the performance of the device. The morphology of the samples was observed using a field-emission scanning electron microscope (FESEM), Raman UV–Vis spectroscopy and Raman photoluminescence (PL) spectroscopy. A CST Microwave used to observe the electric field distribution for all the samples to support the experimental findings. Based on the simulation analysis, two thicknesses of Ag layers (7 nm and 16 nm) were selected to be coated on a side polished optical fiber and tested as a humidity sensor. TiO2 layer was introduced to see the enhancement in the sensing measurements as a suitable material for trapping the photo generated electrons and avoiding charge recombination. From this observation, it can be conclusively shows that the sensitivity of the sensor is improved with integration of Ag NPs and TiO2. Based on the experimental results, the sensor of Ag/TiO2 with 7 nm of Ag layers shows the best characteristics in humidity sensing with good sensitivity and linearity of 0.9201% and 13.4 mW/% RH, respectively
Gel electrolytes with I−/I3− redox mediator based on methylcellulose for dye-sensitized solar cells
No full textA new gel electrolyte comprising methylcellulose (MC), LiBOB and succinonitrile (SN) has been prepared with dimethyl sulfoxide (DMSO) as solvent. The electrolyte with composition 8.73 wt % MC–2.92 wt % LiBOB–1.01 wt % SN–87.34 wt % DMSO exhibits the highest conductivity of 1.18 mS cm-1 at 25 °C. On partially substituting LiBOB with TMAI, the sample designated as TMAI 95 has the highest conducting composition of 8.70 wt % MC–0.14 wt % LiBOB–1.01 wt % SN–2.77 wt % TMAI–0.35 wt % I2–87.03 wt % DMSO. The conductivity is 1.96 mS cm−1. This sample is used to fabricate a dye sensitized photovoltaic cell that converts photons to electricity at an efficiency of 3.46%. The conductivity of this sample has been enhanced to 3.08 mS cm−1 on addition of 1.0 wt % butyl-methyl immidazolium iodide (BMII) ionic liquid and the efficiency of the cell fabricated is 4.63%. Total replacement of LiBOB component in the electrolyte with the same amount of LiI results in a conductivity increase of ∼23.5% and the DSSC exhibits a 5.72% efficiency
Reinforcing information literacy development through a subject-focused resource-based project
No full textThis paper discusses the findings of research investigating the implementation of a resource-based school history project in Malaysian secondary schools. It seeks to understand how the project contributes towards students’ information literacy development. The study took place in selected secondary schools in Kuala Lumpur, Malaysia. A total of 23 students and 5 teachers from four schools participated in the study, employing (a) student focus group interviews, (b) teacher individual interviews, (c) observation, and (d) document analysis as the data collection techniques. In general, although the history project is considered a “research” project by teachers and students, it is found to be a cursory information-gathering and information-compilation type of assignment, which is fully guided by the project guidelines or instructions. While teachers employ a mixture of teaching approaches in the project instruction, the efforts are concentrated on subject matter-related issues such as subject content and project instructions fulfillment. The larger learning experience such as information literacy and learning skills development, as well as research and report writing enhancement, appear to be overlooked in the instructions. The findings also show that (a) information literacy is loosely defined, (b) the “information gathering and information compilation” of the project task is of a superficial nature, and (c) inadequate guidance from teachers has resulted in low information literacy development among students. This study highlights the critical need to address information literacy in the education system, design resource-based assignments with a clear information literacy focus, and the importance of support from teachers for successful development. It provides a foundation for further research on the development of information literacy-focused resource-based school project assignments
A dual fast and slow feature interaction in biologically inspired visual recognition of human action
No full textComputational neuroscience studies have examined the human visual system through functional magnetic resonance imaging (fMRI) and identified a model where the mammalian brain pursues two independent pathways for recognizing biological movement tasks. On the one hand, the dorsal stream analyzes the motion information by applying optical flow, which considers the fast features. On the other hand, the ventral stream analyzes the form information with slow features. The proposed approach suggests that the motion perception of the human visual system comprises fast and slow feature interactions to identify biological movements. The form features in the visual system follow the application of the active basis model (ABM) with incremental slow feature analysis (IncSFA). Episodic observation is required to extract the slowest features, whereas the fast features update the processing of motion information in every frame. Applying IncSFA provides an opportunity to abstract human actions and use action prototypes. However, the fast features are obtained from the optical flow division, which gives an opportunity to interact with the system as the final recognition is performed through a combination of the optical flow and ABM-IncSFA information and through the application of kernel extreme learning machine. Applying IncSFA into the ventral stream and involving slow and fast features in the recognition mechanism are the major contributions of this research. The two human action datasets for benchmarking (KTH and Weizmann) and the results highlight the promising performance of this approach in model modification
Clinico-pathological features of oropharyngeal squamous cell carcinomas in Malaysia with reference to HPV infection
No full textBackground: The incidence of oropharyngeal squamous cell carcinoma (OPSCC) has been rising in Western countries and this has been attributed to human papillomavirus (HPV) infection. p16 expression is a marker for HPV infection and p16 positive OPSCC is now recognized as a separate disease entity. There are only limited data available regarding HPV-related OPSCC in Asian countries and no data from Malaysia. Methods: We identified 60 Malaysian patients with OPSCC over a 12-year period (2004-2015) from four different hospitals in two major cities, Kuala Lumpur and Penang. The detection of HPV was carried out using p16 immunohistochemistry and high risk HPV DNA in situ hybridisation. Results: Overall, 15 (25%) tumours were p16 positive by immunohistochemistry, 10 of which were also positive for high risk HPV DNA by in situ hybridisation. By comparison, a matched cohort of UK patients had a p16 positive rate of 49%. However, between 2009 and 2015, where cases were available from all four hospitals, 13 of 37 (35%) cases were p16 positive. In our Malaysian cohort, 53% of patients were of Chinese ethnicity and 80% of the p16 positive cases were found in these patients; no Indian patients had p16 positive disease, despite representing 35% of the total cohort. Conclusion: The proportion of OPSCCs associated with HPV in Malaysia appears to be lower than in European and American cohorts and could possibly be more prevalent amongst Malaysians of Chinese ethnicity. Further, our data suggests that the burden of HPV-related OPSCC could be increasing in Malaysia. Larger cross-sectional studies of Malaysian patients are required to determine the public health implications of these preliminary findings
Electronic Medical Records in Greece and Oman: A Professional’s Evaluation of Structure and Value
No full textAn Electronic Medical Record (EMR) is a patient’s database record that can be transmitted securely. There are a diversity of EMR systems for different medical units to choose from. The structure and value of these systems is the focus of this qualitative study, from a medical professional’s standpoint, as well as its economic value and whether it should be shared between health organizations. The study took place in the natural setting of the medical units’ environments. A purposive sample of 40 professionals in Greece and Oman, was interviewed. The study suggests that: (1) The demographics of the EMR should be divided in categories, not all of them accessible and/or visible by all; (2) The EMR system should follow an open architecture so that more categories and subcategories can be added as needed and following a possible business plan (ERD is suggested); (3) The EMR should be implemented gradually bearing in mind both medical and financial concerns; (4) Sharing should be a patient’s decision as the owner of the record. Reaching a certain level of maturity of its implementation and utilization, it is useful to seek the professionals’ assessment on the structure and value of such a system
Nanocrystalline K-F zeolite from rice husk silica as an eco-friendly solid base catalyst for the synthesis of jasminaldehyde under microwave irradiation
No full textNanocrystalline aluminosilicate F-type zeolite (K-F, EDI-type structure) was synthesized in an organic template-free system using rice husk ash (RHA) silica source and microwave energy. The morphology, crystallite size, chemical composition, crystallographic and basicity properties of the nanocrystals were studied by using various characterization techniques. The results showed that fully crystalline K-F zeolite (Si/Al ratio = 1.26) with flattened cuboid-like shaped could be obtained within 2 min of crystallization which was considerably very fast. In addition, K-F zeolite nanocrystals was also tested as a solid base catalyst in the microwave-enhanced Aldol condensation reaction of heptanal with benzaldehyde and the six catalytic parameters were studied and optimized. The nanosized K-F zeolite crystals showed good catalytic performance in the studied reaction with 77.1% heptanal conversion and 69.5% jasminaldehyde selectivity under optimum reaction condition. The nanocatalyst was reusable and no significant loss in its catalytic reactivity was observed even after five consecutive reaction cycles