220 research outputs found

    Chemical characteristics of Groundwater in the Akatsi and Ketu Districts of the Volta Region, Ghana

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    The physico-chemical characteristics of the groundwater at Akatsi and Ketu districts were investigated. Water samples were collected from 34 boreholes in the Akatsi District and 27 boreholes in the Ketu District and analysed for their quality parameters, using appropriate certified and acceptable international standard methods. Most of the water quality variables measured were within the WHO and GWCL guidelines for drinking water. The results showed that groundwater in the two districts are soft but slightly acidic with ranges 5.75–7.39 pH units and 5.14–7.15 pH units for Akatsi and Ketu districts, respectively, and mean 6.73 pH units for Akatsi and 6.5 pH units for Ketu. Groundwater in both districts were also mineralized with conductivity ranges 170–6440 mS/cm and 420-5180 mS/cm for Akatsi and Ketu districts, respectively, and mean 1450.9 mS/cm for Akatsi and 1737.1 mS/cm for Ketu. SO4 2- and Cl- ion concentrations in some boreholes in both districts were at such elevated levels that serious health effects and risks might arise after prolonged and continuous intake. The NO3-N concentrations in some of the boreholes in the two districts were present at elevated levels (far above the critical value of 10 mg/l) and might cause cyanosis, a potential health risk in infants

    Cost-effectiveness of different human papillomavirus vaccines in Singapore

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    <p>Abstract</p> <p>Background</p> <p>Human papillomavirus (HPV) vaccines are widely available and there have been studies exploring their potential clinical impact and cost-effectiveness. However, few studies have compared the cost-effectiveness among the 2 main vaccines available - a bivalent vaccine against HPV 16/18, and a quadrivalent vaccine against 6/11/16/18. We explore the cost-effectiveness of these two HPV vaccines in tropical Singapore.</p> <p>Methods</p> <p>We developed a Markov state-transition model to represent the natural history of cervical cancer to predict HPV infection, cancer incidence, mortality, and costs. Cytologic screening and treatment of different outcomes of HPV infection were incorporated. Vaccination was provided to a cohort of 12-year old females in Singapore, followed up until death. Based on available vaccines on the market, the bivalent vaccine had increased effectiveness against a wider range of HPV types, while the quadrivalent vaccine had effectiveness against genital warts. Incremental cost-effectiveness ratios (ICER) compared vaccination to no-vaccination, and between the two vaccines. Sensitivity analyses explored differences in vaccine effectiveness and uptake, and other key input parameters.</p> <p>Results</p> <p>For the no vaccination scenario, 229 cervical cancer cases occurred over the cohort's lifetime. The total discounted cost per individual due to HPV infection was SGD275with28.54discountedlifeyears.With100275 with 28.54 discounted life-years. With 100% vaccine coverage, the quadrivalent vaccine reduced cancers by 176, and had an ICER of SGD12,866 per life-year saved. For the bivalent vaccine, 197 cancers were prevented with an ICER of 12,827perlifeyearsaved.Comparingthebivalenttothequadrivalentvaccine,theICERwas12,827 per life-year saved. Comparing the bivalent to the quadrivalent vaccine, the ICER was 12,488 per life-year saved. However, the cost per QALY saved for the quadrivalent vaccine compared to no vaccine was 9,071,whileitwas9,071, while it was 10,392 for the bivalent vaccine, with the quadrivalent vaccine dominating the bivalent vaccine due to the additional QALY effect from reduction in genital warts. The overall outcomes were most sensitive to vaccine cost and coverage.</p> <p>Conclusion</p> <p>HPV vaccination is a cost-effective strategy, and should be considered a possible strategy to reduce the impact of HPV infection.</p

    Analyses of zebrafish and Xenopus oocyte maturation reveal conserved and diverged features of translational regulation of maternal cyclin B1 mRNA

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    <p>Abstract</p> <p>Background</p> <p>Vertebrate development relies on the regulated translation of stored maternal mRNAs, but how these regulatory mechanisms may have evolved to control translational efficiency of individual mRNAs is poorly understood. We compared the translational regulation and polyadenylation of the cyclin B1 mRNA during zebrafish and <it>Xenopus </it>oocyte maturation. Polyadenylation and translational activation of cyclin B1 mRNA is well characterized during <it>Xenopus </it>oocyte maturation. Specifically, <it>Xenopus </it>cyclin B1 mRNA is polyadenylated and translationally activated during oocyte maturation by proteins that recognize the conserved AAUAAA hexanucleotide and U-rich Cytoplasmic Polyadenylation Elements (CPEs) within cyclin B1 mRNA's 3'<b>U</b>n<b>T</b>ranslated <b>R</b>egion (3'<b>UTR</b>).</p> <p>Results</p> <p>The zebrafish cyclin B1 mRNA was polyadenylated during zebrafish oocyte maturation. Furthermore, the zebrafish cyclin B1 mRNA's 3'UTR was sufficient to stimulate translation of a reporter mRNA during zebrafish oocyte maturation. This stimulation required both AAUAAA and U-rich CPE-like sequences. However, in contrast to AAUAAA, the positions and sequences of the functionally defined CPEs were poorly conserved between <it>Xenopus </it>and zebrafish cyclin B1 mRNA 3'UTRs. To determine whether these differences were relevant to translation efficiency, we analyzed the translational activity of reporter mRNAs containing either the zebrafish or <it>Xenopus </it>cyclin B1 mRNA 3'UTRs during both zebrafish and <it>Xenopus </it>oocyte maturation. The zebrafish cyclin B1 3'UTR was quantitatively less effective at stimulating polyadenylation and translation compared to the <it>Xenopus </it>cyclin B1 3'UTR during both zebrafish and <it>Xenopus </it>oocyte maturation.</p> <p>Conclusion</p> <p>Although the factors that regulate translation of maternal mRNAs are highly conserved, the target sequences and overall sequence architecture within the 3'UTR of the cyclin B1 mRNA have diverged to affect translational efficiency, perhaps to optimize levels of cyclin B1 protein required by these different species during their earliest embryonic cell divisions.</p

    Effect of propolis gel on the in vitro reduction of dentin permeability

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    OBJECTIVE: The aim of this study was to evaluate the capacity of potassium oxalate, fluoride gel and two kinds of propolis gel to reduce the hydraulic conductance of dentin, in vitro. MATERIAL AND METHODS: The methodology used for the measurement of hydraulic conductance of dentin in the present study was based on a model proposed in literature. Thirty-six 1-mm-thick dentin discs, obtained from extracted human third molars were divided into 4 groups (n=9). The groups corresponded to the following experimental materials: GI-10% propolis gel, pH 4.1; GII-30% propolis gel; GIII-3% potassium oxalate gel, pH 4,1; and GIV-1.23% fluoride gel, pH 4.1, applied to the dentin under the following surface conditions: after 37% phosphoric acid and before 6% citric acid application. The occluding capacity of the dentin tubules was evaluated using scanning electron microscopy (SEM) at ×500, ×1,000 and ×2,000 magnifications. Data were analyzed statistically by two-way ANOVA and Tukey's test at 5% significance level. RESULTS: Groups I, II, III, IV did not differ significantly from the others in any conditions by reducing in hydraulic conductance. The active agents reduced dentin permeability; however they produced the smallest reduction in hydraulic conductance when compared to the presence of smear layer (P<0.05). The effectiveness in reducing dentin permeability did not differ significantly from 10% or 30% propolis gels. SEM micrographs revealed that dentin tubules were partially occluded after treatment with propolis. CONCLUSIONS: Under the conditions of this study, the application of 10% and 30% propolis gels did not seem to reduce the hydraulic conductance of dentin in vitro, but it showed capacity of partially obliterating the dentin tubules. Propolis is used in the treatment of different oral problems without causing significant great collateral effects, and can be a good option in the treatment of patients with dentin sensitivity

    European Competition Policy in International Markets

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    International audienceChanges in the institutional, technological and economic environment raise new challenges to the European competition policy. In this context, it is timely for European authorities to appraise the external dimension of the European competition policy as well as its articulation with current internal reforms. Globalisation can increase the costs of monitoring and seriously reduce the ability of European authorities to tackle cross-border anti-competitive conducts. In addition, conflicts are exacerbated by industrial policy motivations. As it is unlikely that the sole application of the territoriality and extraterritoriality principles to competition rules could yield an optimal international competition system, globalisation calls for higher levels and types of cooperation. Given that bilateral cooperation and especially the implementation of comity principles could be of no value when laws or interests are sources of international conflicts, three main paths could be therefore encouraged: The continuous harmonization of rules through the joint action of OECD and ICN; the higher cooperation in the confidential information exchange; the establishment of global anti-trust institutions. Although WTO is legitimate in judging questions related market access and entry barriers, it is less equipped to assess international hard core cartels or M&A reviews. As a substitute for WTO, a multilevel system, like the EU system, could be promoted. For political and pragmatic reasons, it could be composed in a first step of a hard core of countries like the EU, Japan and the U.S. It could be associated with the creation of an international Court of Justice for competition. In addition to these external reforms, some internal reforms could be required. Competition authorities have to develop further competition advocacy to give a higher priority to competition issues in other EU policies and national regulation. A parallel and complementary reform could consist in making the European competition agency independent from State Members' interference

    Myc-regulated microRNAs attenuate embryonic stem cell differentiation

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    Myc proteins are known to have an important function in stem cell maintenance. As Myc has been shown earlier to regulate microRNAs (miRNAs) involved in proliferation, we sought to determine whether c-Myc also affects embryonic stem (ES) cell maintenance and differentiation through miRNAs. Using a quantitative primer-extension PCR assay we identified miRNAs, including, miR-141, miR-200, and miR-429 whose expression is regulated by c-Myc in ES cells, but not in the differentiated and tumourigenic derivatives of ES cells. Chromatin immunoprecipitation analyses indicate that in ES cells c-Myc binds proximal to genomic regions encoding the induced miRNAs. We used expression profiling and seed homology to identify genes specifically downregulated both by these miRNAs and by c-Myc. We further show that the introduction of c-Myc-induced miRNAs into murine ES cells significantly attenuates the downregulation of pluripotency markers on induction of differentiation after withdrawal of the ES cell maintenance factor LIF. In contrast, knockdown of the endogenous miRNAs accelerate differentiation. Our data show that in ES cells c-Myc acts, in part, through a subset of miRNAs to attenuate differentiation

    The use of mesenchymal stem cells for cartilage repair and regeneration: a systematic review.

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    BACKGROUND: The management of articular cartilage defects presents many clinical challenges due to its avascular, aneural and alymphatic nature. Bone marrow stimulation techniques, such as microfracture, are the most frequently used method in clinical practice however the resulting mixed fibrocartilage tissue which is inferior to native hyaline cartilage. Other methods have shown promise but are far from perfect. There is an unmet need and growing interest in regenerative medicine and tissue engineering to improve the outcome for patients requiring cartilage repair. Many published reviews on cartilage repair only list human clinical trials, underestimating the wealth of basic sciences and animal studies that are precursors to future research. We therefore set out to perform a systematic review of the literature to assess the translation of stem cell therapy to explore what research had been carried out at each of the stages of translation from bench-top (in vitro), animal (pre-clinical) and human studies (clinical) and assemble an evidence-based cascade for the responsible introduction of stem cell therapy for cartilage defects. This review was conducted in accordance to PRISMA guidelines using CINHAL, MEDLINE, EMBASE, Scopus and Web of Knowledge databases from 1st January 1900 to 30th June 2015. In total, there were 2880 studies identified of which 252 studies were included for analysis (100 articles for in vitro studies, 111 studies for animal studies; and 31 studies for human studies). There was a huge variance in cell source in pre-clinical studies both of terms of animal used, location of harvest (fat, marrow, blood or synovium) and allogeneicity. The use of scaffolds, growth factors, number of cell passages and number of cells used was hugely heterogeneous. SHORT CONCLUSIONS: This review offers a comprehensive assessment of the evidence behind the translation of basic science to the clinical practice of cartilage repair. It has revealed a lack of connectivity between the in vitro, pre-clinical and human data and a patchwork quilt of synergistic evidence. Drivers for progress in this space are largely driven by patient demand, surgeon inquisition and a regulatory framework that is learning at the same pace as new developments take place
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