18,810 research outputs found

    Impact of dye interlayer on the performance of organic photovoltaic devices

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    The influences of buffer interlayer at the donor/acceptor interface on the open circuit voltage (VOC) of typical copper phthalocyanine (CuPc) / C60 organic photovoltaic devices are studied. Six fluorescent dyes with progressively increasing ionization potentials (I P) were used to investigate the factors influencing the VOC. The short-circuit current and fill factor of CuPc/ C60 device incorporating dye interlayer are lower than those of standard bilayer device. On the other hand, the VOC increases linearly with the I P of dye material and falls off when the I P is equal to or greater than 5.6 eV, in which the energy offset between the highest occupied molecular orbitals at the interlayer/ C60 heterojunction is smaller than the C60 exciton binding energy. The findings underscore the importance of energy offsets in photovoltaic responses. © 2009 American Institute of Physics.published_or_final_versio

    The effects of benfotiamine in attenuating hyperglycemia-induced cardiac pathology

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    Type 2 diabetes is a major global health problem. It is also a risk factor for the onset of cardiovascular diseases, the current leading cause of global mortality. The first part of this mini-review describes hyperglycemia-induced cellular alterations and its effects on cardiac function. In particular, we emphasize the role of hyperglycemia-induced oxidative stress in the activation of non-oxidative glucose pathways (NOGPs), that may contribute to cardiac pathology. For the second part, we evaluate the utility of benfotiamine (a vitamin B1 derivative) in treating diabetes-related cardiac pathology. The focus is on its role in activating the pentose phosphate pathway, which may reduce flux though the NOGPs. A possible role for benfotiamine in activating pro-survival signaling and reducing cell death in the heart is also described. We also discuss benfotiamine’s potential cardioprotective role in preventing the diabetic cardiomyopathy, treating myocardial infarction and maintaining the viability of cardiac progenitor cells. These findings warrant further investigation into the therapeutic potential of benfotiamine in treating diabetes-related cardiac complications.Keywords: Diabetes; cardiovascular disease; hyperglycemia; oxidative stress; non-oxidative glucose pathways; benfotiamin

    EZH2-Mediated H3K27me3 Is Involved in Epigenetic Repression of Deleted in Liver Cancer 1 in Human Cancers

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    Enhancer of zeste homolog 2 (EZH2), the histone methyltransferase of the Polycomb Repressive complex 2 catalyzing histone H3 lysine 27 tri-methylation (H3K27me3), is frequently up-regulated in human cancers. In this study, we identified the tumor suppressor Deleted in liver cancer 1 (DLC1) as a target of repression by EZH2-mediated H3K27me3. DLC1 is a GTPase-activating protein for Rho family proteins. Inactivation of DLC1 results in hyper-activated Rho/ROCK signaling and is implicated in actin cytoskeleton reorganization to promote cancer metastasis. By chromatin immunoprecipitation assay, we demonstrated that H3K27me3 was significantly enriched at the DLC1 promoter region of a DLC1-nonexpressing HCC cell line, MHCC97L. Depletion of EZH2 in MHCC97L by shRNA reduced H3K27me3 level at DLC1 promoter and induced DLC1 gene re-expression. Conversely, transient overexpression of GFP-EZH2 in DLC1-expressing Huh7 cells reduced DLC1 mRNA level with a concomitant enrichment of EZH2 on DLC1 promoter. An inverse relation between EZH2 and DLC1 expression was observed in the liver, lung, breast, prostate, and ovarian cancer tissues. Treating cancer cells with the EZH2 small molecular inhibitor, 3-Deazaneplanocin A (DZNep), restored DLC1 expression in different cancer cell lines, indicating that EZH2-mediated H3K27me3 epigenetic regulation of DLC1 was a common mechanism in human cancers. Importantly, we found that DZNep treatment inhibited HCC cell migration through disrupting actin cytoskeleton network, suggesting the therapeutic potential of DZNep in targeting cancer metastasis. Taken together, our study has shed mechanistic insight into EZH2-H3K27me3 epigenetic repression of DLC1 and advocated the significant pro-metastatic role of EZH2 via repressing tumor and metastasis suppressors.published_or_final_versio

    Enhanced photocatalytic degradation of VOCs using Ln??-TiO?catalysts for indoor air purification

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    Author name used in this publication: F. B. LiAuthor name used in this publication: X. Z. LiAuthor name used in this publication: C. H. AoAuthor name used in this publication: S. C. Lee2004-2005 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Factors influencing project delay : a case study of the Vale Malaysia Minerals Project (VMMP)

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    Delays are one of the biggest problems faced by the construction industry. The delays in construction projects have significant financial and social impact to parties involved in the projects. The main objective of this study is to explore the causes of delay in the Vale Malaysia Minerals Project (VMMP) in Lumut, Perak. This study was conducted by using a qualitative approach. A series of face to face interviews were conducted with an expert from construction organization and VMMP staff. Responses were analysed qualitatively using content analysis and a comprehensive interpretation was developed. The results revealed that several factors that contribute to the delay in VMMP completion, i.e. communication, delayed in material delivery, and poor management on site, etc. Time and cost overrun were the common effects of delays in construction project. The findings of this study will help the project manager or the client to take necessary measures and to use of supply chain management to avoid delays of project completion in a construction project

    A critical review of fragmentation issues in the construction industry

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    The construction industry has generally been regarded as one of the least productive sectors worldwide, with issues ranging from the more common problems, such as delays and cost overruns, to more inter-connected and complex, such as conflicts, safety, client satisfaction, quality, value for money and many more. These poor performances have been closely attributed to the fragmentation that surrounds construction industry practices, whereby construction processes often take place in a sequential manner, and parties typically work in isolation with minimal interfaces between them. This fragmented scenario has ensued the industry as unable to perform efficiently and as being synonymous with problems. This paper therefore aims to critically review past research and literatures towards identifying the fragmentation issues that have been surrounding the construction industry worldwide. The result: 46 factors were compiled from 27 sources, thus indicating that fragmentation is indeed a significant and universal problem within the construction industry. The findings in this paper is expected to provide a platform for effective solutions to be strategized in future towards improving productivity rates in construction

    Photocatalytic conversion of NO using TiO?-NH?catalysts in ambient air environment

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    Author name used in this publication: F. B. LiAuthor name used in this publication: X. Z. LiAuthor name used in this publication: C. H. AoAuthor name used in this publication: S. C. Lee2004-2005 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Phosphorylation of nucleophosmin at threonine 234/237 is associated with HCC metastasis

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    Hepatocellular carcinoma (HCC) is frequently complicated by the occurrence of intrahepatic and extrahepatic metastases, leading to poor prognosis. To improve the prognosis for HCC patients, there is an urgent need to understand the molecular mechanisms of metastasis in HCC. Since protein Serine/Threonine phosphorylation emerges to be an important posttranslational modification critical in signaling process associated with cell proliferation, survival and metastasis, we employed a pair of primary tumor-derived and corresponding lung-metastatic counterparts (PLC/PRF/5-PT and PLC/PRF/5-LM) and aimed to identify these changes using CelluSpot Serine/Threonine kinase peptide array. Upon analysis, we found phosphorylated level of nucleophosmin (NPM) at Threonine 234/237 (p-NPM-Thr234/237) had remarkably high level in metastatic HCC cells (PLC-LM) than the corresponding primary HCC cell line (PLC-PT). Similar observation was observed in another match primary and their metastatic counterparts (MHCC-97L and MHCC-97H). By immunohistochemical staining, p-NPM-Thr234/237 was consistently found to be preferentially expressed in metastatic HCCs when compared with primary HCC in 28 HCC cases (p < 0.0001). By overexpressing Flag-tagged NPM and its phosphorylation site mutant (Thr234/237A) into low p-NPM-Thr234/237 expressing cells (Hep3B and Huh7) using a lentiviral based approach, we demonstrated that p-NPM-Thr234/237 is critical in invasion and migration of HCC cells, and this effect was mediated by cyclin-dependent kinase 1 (CDK1). Wild-type NPM was found to physically interact with a metastatic gene, ROCK2, and defective in Thr234/237 phosphorylation decreased its binding affinity, resulting in decrease in ROCK2 mediated signaling pathway. Identification of CDK1/p-NPM/ROCK2 signaling pathway provides a novel target for molecular therapy against HCC metastasis.published_or_final_versio
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