Elimination of Cu (II) and Zn (II) ions in mono-element and the bi-element aqueous solutions by adsorption on natural clay of Bikougou (Gabon)

This work was undertaken to evaluate the potential of the clay of Bikougou to remove copper (II) and zinc (II) ions (Cu2+ and Zn2+) in  mono-element and binary aqueous solutions. The experiments werecarried out by employing the batch technique through the variations of pH, clay mass, ionic strength, concentration in metal, temperature and contact time. The quantity of ions coppers (II) or zinc (II) adsorbed increases when the pH increases up to pH=5 and beyond, there is precipitation of the metal hydroxides; the quantity of metal ions adsorbed decreases when the clay mass or the ionic force increases. The average adsorption energies of copper (II) and zinc (II) ions are indicative of endothermic reactions. The modeling of the experimental results is better achieved by application ofFreundlich adsorption isotherm and Langmuir adsorption isotherm  concerning the adsorption of Cu (II) ions with correlation coefficients of 0.98 and 0.93, respectively. The Langmuir adsorption isotherm and Freundlich adsorption isotherm are all applicable for describing the experimental result of isotherm adsorption of Zn (II) ions with correlation coefficient respectively, 0.99 and 0.96. The kinetic which shows more clearly the observed phenomenon is that of the pseudo-second order with the coefficients of correlation close to 0.99. In the binary system copper (II) - zinc (II) the adsorption of copper (II) is favoured compared to that of zinc (II). All these results have shown efficiency as adsorbent of theclay from Bikougou to eliminate Cu2+and zinc (II) ions in mono-element or bi-element aqueous solutions. In the mono-element solution, the adsorption rate varied from 98.59 to 94.41% for the Cu(II) ions and from 86.76 to 53.80% for Zn (II) ions.Key words: System of bi-element, copper and zinc, adsorption, technique in batch, natural clay mixture

Examining outcomes following thrombolysis in an increasingly older and dependent stroke population

We are grateful for the support of the nurses from Chest, Heart and Stroke Scotland for assisting in obtaining follow-up functional status at three months.Peer reviewedPublisher PD

Co-designing adaptation decision support: meeting common and differentiated needs

As exposure to climate change increases, there is a growing need for effective adaptation decision support products across public, private and community sectors and at all scales (local, regional, national, international). Numerous guidance products have been developed, but it is not clear to what extent they meet end-user needs, especially as development has been fragmented and many products lack continuing support, learning and improvement. It is timely to address the development of more intentional and coordinated support strategies that draw on the experience to date and what end-users themselves say they need. We have taken such an approach to co-design future support strategies for Australia at national and sub-national (sectoral, locational and/or jurisdictional) levels. Several supporting frameworks are introduced to assist in the clarification of common needs (e.g. incorporation of leading adaptation practices) versus differentiated needs across sectors (e.g. a ‘decision entry points’ framework) and individual organisations (e.g. a ‘decision domains’ framework). The collaborative process also identified key principles that should underpin national and sub-national support strategies and product development. A comparison with international experience indicates that the findings and principles should also be relevant to other nations, and to international and sub-national agencies developing adaptation support strategies and products.The Leading Adaptation Practices and Support program was funded by the NCCARF (first phase) and the federal Department of Environment and CSIRO (second phase)

The Land-Potential Knowledge System (LandPKS): mobile apps and collaboration for optimizing climate change investments

Massive investments in climate change mitigation and adaptation are projected during coming decades. Many of these investments will seek to modify how land is managed. The return on both types of investments can be increased through an understanding of land potential: the potential of the land to support primary production and ecosystem services, and its resilience. A Land-Potential Knowledge System (LandPKS) is being developed and implemented to provide individual users with point-based estimates of land potential based on the integration of simple, geo-tagged user inputs with cloud-based information and knowledge. This system will rely on mobile phones for knowledge and information exchange, and use cloud computing to integrate, interpret, and access relevant knowledge and information, including local knowledge about land with similar potential. The system will initially provide management options based on long-term land potential, which depends on climate, topography, and relatively static soil properties, such as soil texture, depth, and mineralogy. Future modules will provide more specific management information based on the status of relatively dynamic soil properties such as organic matter and nutrient content, and of weather. The paper includes a discussion of how this system can be used to help distinguish between meteorological and edaphic drought

Extraction of parabens from cosmetic and environmental water samples coupled with uv-visible spectroscopy

An effective and fast vortex-assisted dispersive liquid–liquid extraction method was developed for the extraction of paraben in cosmetic samples and water samples. The paraben was determined and quantifi ed using ultraviolet-visible (UV-Vis) spectrometry. A response surface methodology (RSM) based on the central composite design was used for the optimization of factors (composition of the extractant, volume of extractant, extraction time, centrifugation time, and centrifugation velocity) affecting the extraction effi ciency of the procedure. The optimum parameters for vortexassisted dispersive liquid–liquid extraction (VA-DLLE) are: chloroform used as the extractant solvent, 5 ml volume of extractant, 3 min extraction time, 5 min centrifugation time, and 2400 rpm centrifugation velocity. The limit of detection (LOD) and the limit of quantifi cation (LOQ) for paraben are 0.0476 and 0.1442 μg/mL, respectively. Spiked cosmetic samples have the extraction recoveries in the range of 81.2–96.8%, whereas spiked water sample extraction recoveries were in the range of 88.8–100.63%. Each sample was repeated (n = 2), with a relative standard deviation of <5.74% for cosmetic samples and <9.03% for water samples. In conclusion, this extraction method is fast and inexpensive for the extraction of paraben

Application of a Colorimetric Assay to Identify Putative Ribofuranosylaminobenzene 5'-Phosphate Synthase Genes Expressed with Activity in Escherichia coli

Tetrahydromethanopterin (H(4)MPT) is a tetrahydrofolate analog originally discovered in methanogenic archaea, but later found in other archaea and bacteria. The extent to which H(4)MPT occurs among living organisms is unknown. The key enzyme which distinguishes the biosynthetic pathways of H(4)MPT and tetrahydrofolate is ribofuranosylaminobenzene 5'-phosphate synthase (RFAP synthase). Given the importance of RFAP synthase in H(4)MPT biosynthesis, the identification of putative RFAP synthase genes and measurement of RFAP synthase activity would provide an indication of the presence of H(4)MPT in untested microorganisms. Investigation of putative archaeal RFAP synthase genes has been hampered by the tendency of the resulting proteins to form inactive inclusion bodies in Escherichia coli. The current work describes a colorimetric assay for measuring RFAP synthase activity, and two modified procedures for expressing recombinant RFAP synthase genes to produce soluble, active enzyme. By lowering the incubation temperature during expression, RFAP synthase from Archaeoglobus fulgidus was produced in E. coli and purified to homogeneity. The production of active RFAP synthase from Methanothermobacter thermautotrophicus was achieved by coexpression of the gene MTH0830 with a molecular chaperone. This is the first direct biochemical identification of a methanogen gene that codes for an active RFAP synthase

Under positive pressure: how stakeholder pressure affects corporate social responsibility implementation

This study tests a model that links stakeholder pressure to the implementation of corporate social responsibility (CSR) activities and market performance. Stakeholder groups and competitors might exert pressure on companies to implement CSR, which could lead to positive effects on market performance. Using structural equation modeling (SEM), the authors find that stakeholders and competitors exert pressure differently. The effect of CSR implementation on market performance is moderated by market dynamism: It affects market performance more in dynamic environments. The authors discuss implications for both companies and stakeholders

Trials of large group teaching in Malaysian private universities: a cross sectional study of teaching medicine and other disciplines

<p>Abstract</p> <p>Background</p> <p>This is a pilot cross sectional study using both quantitative and qualitative approach towards tutors teaching large classes in private universities in the Klang Valley (comprising Kuala Lumpur, its suburbs, adjoining towns in the State of Selangor) and the State of Negeri Sembilan, Malaysia. The general aim of this study is to determine the difficulties faced by tutors when teaching large group of students and to outline appropriate recommendations in overcoming them.</p> <p>Findings</p> <p>Thirty-two academics from six private universities from different faculties such as Medical Sciences, Business, Information Technology, and Engineering disciplines participated in this study. SPSS software was used to analyse the data. The results in general indicate that the conventional instructor-student approach has its shortcoming and requires changes. Interestingly, tutors from Medicine and IT less often faced difficulties and had positive experience in teaching large group of students.</p> <p>Conclusion</p> <p>However several suggestions were proposed to overcome these difficulties ranging from breaking into smaller classes, adopting innovative teaching, use of interactive learning methods incorporating interactive assessment and creative technology which enhanced students learning. Furthermore the study provides insights on the trials of large group teaching which are clearly identified to help tutors realise its impact on teaching. The suggestions to overcome these difficulties and to maximize student learning can serve as a guideline for tutors who face these challenges.</p