19672 research outputs found
Sort by
Induction of apoptosis by pinostrobin in human cervical cancer cells: Possible mechanism of action
No full textPinostrobin (PN) is a naturally occurring dietary bioflavonoid, found in various medicinal herbs/plants. Though anti-cancer potential of many such similar constituents has been demonstrated, critical biochemical targets and exact mechanism for their apoptosis-inducing actions have not been fully elucidated. The present study was aimed to investigate if PN induced apoptosis in cervical cancer cells (HeLa) of human origin. It is demonstrated that PN at increasing dose effectivity reduced the cell viability as well as GSH and NO2- levels. Condensed nuclei with fragmented chromatin and changes in mitochondrial matrix morphology clearly indicated the role of mitochondria in PN induced apoptosis. A marked reduction in mitochondrial membrane potential and increased ROS production after PN treatment showed involvement of free radicals, which in turn further augment ROS levels. PN treatment resulted in DNA damage, which could have been triggered by an increase in ROS levels. Decrease in apoptotic cells in the presence of caspase 3 inhibitor in PN-treated cells suggested that PN induced apoptosis via caspase dependent pathways. Additionally, a significant increase in the expression of proteins of extrinsic (TRAIL R1/DR4, TRAIL R2/DR5, TNF RI/TNFRSF1A, FADD, Fas/TNFRSF6) and intrinsic pathway (Bad, Bax, HTRA2/Omi, SMAC/Diablo, cytochrome C, Pro-Caspase-3, Cleaved Caspase-3) was observed in the cells exposed to PN. Taken together, these observations suggest that PN efficiently induces apoptosis through ROS mediated extrinsic and intrinsic dependent signaling pathways, as well as ROS mediated mitochondrial damage in HeLa cells
A case-control study and meta-analysis confirm glucokinase regulatory gene rs780094 is a risk factor for gestational diabetes mellitus
No full textBackground: Although the influence of a common variant in the glucokinase regulatory gene (GCKR rs780094) in type 2 diabetes mellitus has been well documented, less data however, is available of its role in gestational diabetes mellitus (GDM). We carried out a case control study to assess the association between GCKR rs780094 and GDM in the Asian, and also a meta-analysis to further assess the strength of the association. Methods: Demographic, clinical and genotype data were determined for 1122 women (267 cases and 855 controls) recruited from the University of Malaya Medical Centre in the Klang Valley, Kuala Lumpur. Relevant articles were identified from Pubmed, Embase, MEDLINE, and Web of Science. Extraction of data was carried out and summary estimates of the association between rs780094 and GDM were examined. Results: The frequency of risk allele C was significantly higher in the cases than controls (OR 1.34, 95% CI 1.09–1.66, P = 0.006). The C allele was also associated with increased level of random 2-hour fasting plasma glucose and pregravid body mass index. Meta-analysis further confirmed the association of the GCKR rs780094 with GDM (OR 1.32, 95% CI 1.14–1.52, P = 0.0001). Conclusion: This study strongly suggests that GCKR rs780094-C is associated with increased risk of GDM
Integrated geoelectrical resistivity and hydrogeochemical methods for delineating and mapping heavy metal zone in aquifer system
No full textA novel study on using geoelectrical resistivity, soil property, and hydrogeochemical analysis methods for delineating and mapping of heavy metal in aquifer system is presented in this paper. A total of 47 surveys of geoelectrical resistivity with Wenner configuration were conducted to determine the subsurface and the groundwater characteristics. The groundwater sample from 53 existing wells and 2 new wells has been analyzed to derive their water chemical content. The chemical analysis was done on the soil sample obtained from new two wells and from selected locations. The water and soil chemical analysis results from the new two wells were used as calibration in resistivity interpretation. The occurrence of heavy metal in aquifer system was expected to detect using the geoelectrical resistivity survey for the whole study area. The result of groundwater analysis shows that the groundwater sample contains a relatively low concentration of Fe (< 0.3 mg/L) elongating from the south up to the middle region. While in the middle and the northwestern, Fe concentration is relatively high (around 12 mg/L). Chemical analysis of soil sample shows that in the lower resistivity zone (< 18 Ωm), Al and Fe concentrations are comparatively high with an average of 68,000 and 40,000 mg/kg, respectively. Starting from the middle to the northwestern zone, the resistivity value appears to be low. It is definitely caused by higher Al and Fe concentration within the soil, and it is supported also by lower total anion content in the groundwater. While the resistivity value of more than 40 Ωm in aquifers is obtained in the zone which Fe concentration is relatively lower in the soil but not present in the groundwater. Correlation Fe concentration in the soil and Fe concentration in the groundwater sample shows the trend of positively linear; however, the Al concentration in soil has no correlation with Al content in groundwater. Finally, the probability of high heavy metal zone in the aquifer system is easily delineated by the distribution of geoelectrical resistivity presented in depth slice shapes which extend from the Boundary Range Composite Batholith in the north to the northwest
High performance supercapattery incorporating ternary nanocomposite of multiwalled carbon nanotubes decorated with Co 3 O 4 nanograins and silver nanoparticles as electrode material
No full textCobalt oxide (Co3O4) nanograins were in situ grown on chemically activated multiwall carbon nanotubes (MWCNT) and anchored with silver (Ag) nanoparticles to form a ternary nanocomposite (MWCNT-Co3O4-Ag) by simple single step hydrothermal route. The structural crystallinity and successful synthesis of MWCNT-Co3O4-Ag nanocomposite were confirmed by X-ray diffraction. The surface morphology, homogeneity, specific surface area and crystallinity were evaluated by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy with mapping, Brunauer Emmett Teller and X-ray diffraction analysis, respectively. Cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy were conducted in 1 M KOH electrolyte to analyze electrochemical performance of the prepared samples as an electrode material for supercapattery. The MWCNT-Co3O4-Ag nanocomposite witnessed the maximum specific capacity of 83.88 Cg-1 at 0.6 Ag-1 which is substantially higher than MWCNT-Co3O4 (55.33 Cg-1) and Co3O4 nanograins (39.24 Cg-1) in standard three electrode cell system. The remarkable electrochemical performance of ternary nanocomposite was associated with the effect of Co3O4 nanograins, conductive platform provided by the MWCNT and synergistic effect of Ag nanoparticles. The supercapattery devices were fabricated in a configuration of MWCNT-Co3O4-Ag//activated carbon. The hybrid device was capable to operate in stable potential window of 1.5 V even at higher scan rates. It was observed that the fabricated supercapattery showed an energy density of 16.5 Whkg−1 with power density of 297.5 Wkg-1 at current density of 0.2 Ag-1. Additionally, life cycle test revealed that supercapattery was highly stable and lost only 6.4% of its initial capacity after 3000 cycles
Statistical feature extraction method for wood species recognition system
No full textA cascaded wood species recognition system using simple statistical properties of the wood texture is presented where a total of 24 statistical features are extracted from each wood sample. They are mainly vessel features that allow a broad initial grouping of wood texture using fuzzy logic. Then, a neural network classifier is used to refine the broad grouping into the final wood species classification. The proposed system emulates the classification approach normally taken by human experts when analyzing wood species based on texture. A comprehensive set of experiments was performed on a database composed of 3000 macroscopic images of 30 different wood species to evaluate the effectiveness of the system. Finally, its performance is compared with previous works in terms of classification accuracy
Gastronomy, Tourism, and the Soft Power of Malaysia
No full textThis review article examines the link between tourism and soft power in view of five (four proposed by Ooi) interlinked ways (approaches). It also looks whether Malaysia (as a case study) by using the soft power approaches has achieved the desired outcomes or not. The article found that Ooi’s approach is adequate to analyze a country’s tourism policy, strategies, tourists’ perceptions, and the outcomes of tourism. However, it has ignored the independent role of gastronomy, the business-enabling environment, recognition of the cultural and natural sites as world heritage, and methodological approach to address negative stereotypes against other nationalities. The article also maintains that Malaysia has efficiently used the soft power approach and maximally received benefits from it without the use of coercive powers. This research offers insight into different power tools applied in a variety of contexts which shape the image of the country
Mobile experience evaluation of an e-reader app
No full textIn recent years, there is a tremendous proliferation and growth in the development of mobile applications. An important aspect in the advancement of this technology is the usability evaluation of these mobile applications. In this study, a laboratory-based mobile usability assessment was conducted on the Amazon Kindle e-book reader app using 15 users who performed five tasks on the mobile app. A post-test questionnaire was administered to capture users' perception of the mobile usability of the app. The outcomes show that most of the participants were satisfied and delighted with the services offered by the app. On all the four user experience factors evaluated, that is, perceived ease-of-use, perceived visibility, perceived enjoyability, and perceived efficiency, the outcome shows that the participants had an excellent mobile experience with the app
Indirect effect of management support on users’ compliance behaviour towards information security policies
No full textBACKGROUND: Health information systems are innovative products designed to improve the delivery of effective healthcare, but they are also vulnerable to breaches of information security, including unauthorised access, use, disclosure, disruption, modification or destruction, and duplication of passwords. Greater openness and multi-connectedness between heterogeneous stakeholders within health networks increase the security risk. OBJECTIVE: The focus of this research was on the indirect effects of management support (MS) on user compliance behaviour (UCB) towards information security policies (ISPs) among health professionals in selected Malaysian public hospitals. The aim was to identify significant factors and provide a clearer understanding of the nature of compliance behaviour in the health sector environment. METHOD: Using a survey design and stratified random sampling method, self-administered questionnaires were distributed to 454 healthcare professionals in three hospitals. Drawing on theories of planned behaviour, perceived behavioural control (self-efficacy (SE) and MS components) and the trust factor, an information system security policies compliance model was developed to test three related constructs (MS, SE and perceived trust (PT)) and their relationship to UCB towards ISPs. RESULTS: Results showed a 52.8% variation in UCB through significant factors. Partial least squares structural equation modelling demonstrated that all factors were significant and that MS had an indirect effect on UCB through both PT and SE among respondents to this study. CONCLUSION: The research model based on the theory of planned behaviour in combination with other human and organisational factors has made a useful contribution towards explaining compliance behaviour in relation to organisational ISPs, with trust being the most significant factor. In adopting a multidimensional approach to management-user interactions via multidisciplinary concepts and theories to evaluate the association between the integrated management-user values and the nature of compliance towards ISPs among selected health professionals, this study has made a unique contribution to the literature
Improvement of product selectivity in bicarbonate reduction into formic acid on a tin-based catalyst by integrating nano-diamond particles
No full textIn this study, the efficiency of electrochemical reduction of bicarbonate into formic acid was improved by using a composite electrode made up of tin (Sn), nanodiamond (ND) and carbon nanotube (CNT). In the absence of ND, a compositional ratio of 10/90 (Sn/CNT) demonstrated the highest current density. However, by adding ND in a compositional ratio of 10/90/100 (Sn/CNT/ND) the highest efficiency towards formate/formic acid was achieved. It was observed that the presence of ND enhanced the selectivity of product for formic acid. The effects of bicarbonate concentration and scan rate have also been studied to understand the reduction mechanism. The peak potential shifted towards larger negative values of applied potential with an increase in the scan rate from 0.01 to 0.1 V/s, confirming the irreversible nature of the reduction process. The linear relationship between the current and the square root of the scan rate (with a slope value of 0.519) suggested that the reaction process is fully diffusion-controlled. Formic acid was produced using both electrodes; however, the electrode containing nano-diamond successfully improved the process yield for formic acid. Electrochemical impedance study revealed a significant difference between Warburg coefficient for oxidation and reduction processes with values of 29.63 × 1012 and 67.4 Ω. S−0.5 for the applied potentials of 0.5 V and −0.4 V, respectively. This difference confirmed a low resistance at the electrode/electrolyte interface for the reduction potentials
Development of catalyst complexes for upgrading biomass into ester-based biolubricants for automotive applications: a review
No full textBiomass-derived oils are recognised as the most promising renewable resources for the production of ester-based biolubricants due to their biodegradable, non-toxic and metal adhering properties. Homogeneous acid catalysts have been conventionally used in catalytic esterification and transesterification for the synthesis of ester-based biolubricants. Although homogeneous acid catalysts encounter difficulty during phase separation, they exhibit superior selectivity and good stereochemistry and regiochemistry control in the reaction. Consequently, transition metal complex catalysts (also known as homogeneous organometallic catalysts) are proposed for biolubricant synthesis in order to achieve a higher selectivity and conversion. Herein, the potential of both homogeneous transition metal complexes and heterogeneous supported metal complexes towards the synthesis of biolubricants, particularly, in esterification and transesterification, as well as the upgrading process, including hydrogenation and in situ hydrogenation-esterification, is critically reviewed