87 research outputs found

    Exploring Sheraoh Island at South-Eastern Qatar: First Distributional Records of Some Inland and Offshore Biota with Annotated Checklist

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    Sheraoh island is the most remote among Qatari islands, nearly 73.5 km south-eastern of the mainland of the peninsula. In March 2010, a preliminary general survey of the species was conducted. Observations were made partly by wading and snorkeling in the intertidal zone and partly by surveying the inland habitats. In total the 31 species were recorded, 4 species of halophyte plants: Halopeplis perfoliata, Suaeda vermiculata, Salsola baryosoma and Zygophyllum qatarense, one unexpected terrestrial mammal: the cape hare Lepus capensis, 2 species of visiting birds: Motacilla flava and Anthus campestus and one species of sea bird. Phalacrocorax nigrogularis, one dolphin species: Sousa chinensis. The largest richness was found in the marine habitats, 3 species of sea weeds: Colpomenia sinusa, Padina boergesenii and Sargassum boveanum, 3 species of corals: Anomastraea irregularis, Platygyra lamellina and Porites harrisoni, 2 species of nudibranchs: Chromodoris cazae and Chromodoris sp. (unidentified)., 4 crab species: Hermit crab (unidentified), Etisus laevimanus, Grapsus albolineatus and Lambrus prensor, 4 species of echinoderms: Pentacentral mammillatus, Ophiothela venusta, Diadema setosum and Echinometra mathaei, 5 species of bony fish: Doryrhamphus sp. (larva), Cypserulus oligolepis, Lethrinus nebulosus, Cephalopholis miniatus and Hemiramphus marginatus, one species of sea snakes: Hydrophis sp. The most striking result is to collect an unknown nudibranch species and to report the cape hare which is unexpected inhabitant. All figures of this study are published for the first time in Qatar.Qatar Universit

    An examination of assessment practices in colleges of business at various Middle East countries compared to the USA

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    This study reports the results of a survey conducted during 2007 which was mailed to deans of schools of business at institutions of higher education located within the USA and the Middle East. Schools of business are now more engaged in assessment activities than a few years ago. Assessment activities are more costly and more emphasis seems to be placed on assessing communication skills, critical thinking, and professional knowledge. Colleges of business are relaying heavily on course-embedded measures, followed by indirect measures of assessment. Curriculum and instructional changes were the top-ranked uses of assessment results. Although almost the same percentage of colleges of business in 2007 has specific curriculum/programme objectives as they did in 1999 (92% in 2007 and 88% in 1999), significantly more US colleges actually assess their objectives. While 65% of the US institutions reported assessment activities annually, only 25% of Middle Eastern universities assessed their curriculum annually

    The role of climatic-design-operational parameters on combined PV/T collector performance: a critical review

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    PV/T technology attracted numerous researchers and professionals during the last decades. There are many review papers in the literature evaluated the R&D aspects of PV/T collectors. In fact, there are abundant of case studies discussed the parameters of climate, design and operational conditions affected the PV/T collector performance. But, a comprehensive compilation of the information of those case studies is still a missing link in the literature. Hence, this paper intended to review thoroughly the information regarding the parameters affecting the PV/T collector performance mainly and PV module performance partially. The parameters are supported with the most available R&D to measure the accurate influence of each parameter on the performance. The outcomes from the study are highlighted in lessons learned section

    Epigenetic associations of type 2 diabetes and BMI in an Arab population

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    Background The prevalence of type 2 diabetes (T2D) and obesity has dramatically increased within a few generations, reaching epidemic levels. In addition to genetic risk factors, epigenetic mechanisms triggered by changing environment are investigated for their role in the pathogenesis of these complex diseases. Epigenome-wide association studies (EWASs) have revealed significant associations of T2D, obesity, and BMI with DNA methylation. However, populations from the Middle East, where T2D and obesity rates are highest worldwide, have not been investigated so far. Methods We performed the first EWAS in an Arab population with T2D and BMI and attempted to replicate 47 EWAS associations previously reported in Caucasians. We used the Illumina Infinium HumanMethylation450 BeadChip to quantify DNA methylation in whole blood DNA from 123 subjects of 15 multigenerational families from Qatar. To investigate the effect of differing genetic background and environment on the epigenetic associations, we further assessed the effect of replicated loci in 810 twins from UK. Results Our EWAS suggested a novel association between T2D and cg06721411 (DQX1; p value = 1.18 × 10−9). We replicated in the Qatari population seven CpG associations with BMI (SOCS3, p value = 3.99 × 10−6; SREBF1, p value = 4.33 × 10−5; SBNO2, p value = 5.87 × 10−5; CPT1A, p value = 7.99 × 10−5; PRR5L, p value = 1.85 × 10−4; cg03078551, intergenic region on chromosome 17; p value = 1.00 × 10−3; LY6G6E, p value = 1.10 × 10−3) and one with T2D (TXNIP, p value = 2.46 × 10−5). All the associations were further confirmed in the UK cohort for both BMI and T2D. Meta-analysis increased the significance of the observed associations and revealed strong heterogeneity of the effect sizes (apart from CPT1A), although associations at these loci showed concordant direction in the two populations. Conclusions Our study replicated eight known CpG associations with T2D or BMI in an Arab population. Heterogeneity of the effects at all loci except CPT1A between the Qatari and UK studies suggests that the underlying mechanisms might depend on genetic background and environmental pressure. Our EWAS results provide a basis for comparison with other ethnicities

    Ki67 expression in invasive breast cancer: the use of tissue microarrays compared with whole tissue sections.

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    BACKGROUND: Although the prognostic value of Ki67 in breast cancer is well documented, using optimal cut-points for patient stratification, reproducibility of the scoring and interpretation of the results remains a matter of debate particularly when using tissue microarrays (TMAs). This study aims to assess Ki67 expression assessed on TMAs and their matched whole tissue sections (WTS). Moreover, whether the cut-off used for WTS is reproducible on TMA in BC molecular classes and the association between Ki67 expression cut-off, assessed on TMAs and WTS, and clinicopathological parameters and patient outcome were tested. METHOD: A large series (n = 707) of primary invasive breast tumours were immunostained for Ki67 using both TMA and WTS and assessed as percentage staining and correlated with each other, clinicopathological parameters and patient outcome. In addition, MKI67 mRNA expression was correlated with Ki67 protein levels on WTS and TMAs in a subset of cases included in the METABRIC study. RESULTS: There was moderate concordance in Ki67 expression between WTS and TMA when analysed as a continuous variable (Intraclass correlation coefficient = 0.61) and low concordance when dichotomised (kappa value = 0.3). TMA showed low levels of Ki67 with mean percentage of expression of 35 and 22% on WTS and TMA, respectively. MKI67 mRNA expression was significantly correlated with protein expression determined on WTS (Spearman Correlation, r = 0.52) and to a lesser extent on TMA (r = 0.34) (p < 0.001). Regarding prediction of patient outcome, statistically significant differences were detected upon stratification of patients with tumours expressing Ki67 at 10, 15, 20, 25 or 30% in TMA. Using TMA, ≥20% Ki67 provided the best prognostic cut-off particularly in triple-negative and HER2-positive classes. CONCLUSION: Ki67 expression in breast cancer can be evaluated using TMA although different cut-points are required to emulate results from WTS. A cut-off of ≥20% for Ki67 expression in BC provides the best prognostic correlations when TMAs are used

    CXCR4 Mediated Chemotaxis Is Regulated by 5T4 Oncofetal Glycoprotein in Mouse Embryonic Cells

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    5T4 oncofetal molecules are highly expressed during development and upregulated in cancer while showing only low levels in some adult tissues. Upregulation of 5T4 expression is a marker of loss of pluripotency in the early differentiation of embryonic stem (ES) cells and forms an integrated component of an epithelial-mesenchymal transition, a process important during embryonic development and metastatic spread of epithelial tumors. Investigation of the transcriptional changes in early ES differentiation showed upregulation of CXCL12 and down-regulation of a cell surface protease, CD26, which cleaves this chemokine. CXCL12 binds to the widely expressed CXCR4 and regulates key aspects of development, stem cell motility and tumour metastasis to tissues with high levels of CXCL12. We show that the 5T4 glycoprotein is required for optimal functional cell surface expression of the chemokine receptor CXCR4 and CXCL12 mediated chemotaxis in differentiating murine embryonic stem cells and embryo fibroblasts (MEF). Cell surface expression of 5T4 and CXCR4 molecules is co-localized in differentiating ES cells and MEF. By contrast, differentiating ES and MEF derived from 5T4 knockout (KO) mice show only intracellular CXCR4 expression but infection with adenovirus encoding mouse 5T4 restores CXCL12 chemotaxis and surface co-localization with 5T4 molecules. A series of chimeric constructs with interchanged domains of 5T4 and the glycoprotein CD44 were used to map the 5T4 sequences relevant for CXCR4 membrane expression and function in 5T4KO MEF. These data identified the 5T4 transmembrane domain as sufficient and necessary to enable CXCR4 cell surface expression and chemotaxis. Furthermore, some monoclonal antibodies against m5T4 can inhibit CXCL12 chemotaxis of differentiating ES cells and MEF which is not mediated by simple antigenic modulation. Collectively, these data support a molecular interaction of 5T4 and CXCR4 occurring at the cell surface which directly facilitates the biological response to CXCL12. The regulation of CXCR4 surface expression by 5T4 molecules is a novel means to control responses to the chemokine CXCL12 for example during embryogenesis but can also be selected to advantage the spread of a 5T4 positive tumor from its primary site
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