838 research outputs found

    Effects of Toxic Cyanobacteria (Microcystis Aeruginosa) on the Feeding and Reproduction Ecology of the Copepod Eurytemora Affinis from Green Bay, Lake Michigan

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    Toxic Cyanobacteria is known to be a bad food source to consumers as well as a main contributor to harmful algal blooms. This study investigates the feeding relationship between an invasive copepod in the Great Lakes system, Eurytemora affinis, and a toxic strain of cyanobacteria, Microcystis aeruginosa. E.affinis has been shown to feed on toxic cyanobacteria. By measuring the filtering rate, ingestion rate, egg production and offspring size between three different food conditions, we hope to gain insight into the effects of toxic cyanobacteria on the feeding and reproduction of this copepod. Food sources include a good green algal food source of Scenedesmus quadricauda, a mixture of the good food source and the toxic M. aeruginosa, and a mixture of the good food source and cyanobacteria filtrate. Results indicated significant differences in the filtering and ingestion rates between the filtrate treatment and the other two food treatments. On the other hand, there were no differences found in egg number or nauplius size

    State detection using coherent Raman repumping and two-color Raman transfers

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    We demonstrate state detection based on coherent Raman repumping and a two-color Raman state transfer. The Raman coupling during detection selectively eliminates unwanted dark states in the fluorescence cycle without compromising the immunity of the desired dark state to off-resonant scattering. We demonstrate this technique using 137Ba+^{137}\mathrm{Ba}^+ where a combination of Raman coupling and optical pumping leaves the D3/2D_{3/2} F"=3,mF"=3\ket{F"=3,m_F"=3} metastable state optically dark and immune to off-resonant scattering. All other states are strongly coupled to the upper P1/2P_{1/2} levels. We achieve a single shot state-detection efficiency of 89.6(3)89.6(3)% in a 1ms1\mathrm{ms} integration time, limited almost entirely by technical imperfections. Shelving to the F"=3,mF"=3\ket{F"=3,m_F"=3} state before detection is performed via a two-color Raman transfer with a fidelity of 1.00(3)1.00(3)

    Predicting The Effect of Moisture Content On The Flexural Properties of Douglas-Fir Dimension Lumber

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    Current procedures for adjusting estimates of the mechanical properties of lumber for changes in moisture content are based on trends in the observed means. The present study was initiated to develop analytical procedures for adjusting estimates of the flexural properties of 2-inch-thick Douglas-fir dimension lumber that would be applicable to all levels of the flexural properties. Equations are derived for adjusting modulus of rupture (MOR), modulus of elasticity (MOE), moment capacity (RS = MOR x section modulus), and flexural stiffness (EI = MOEX moment of inertia) for changes in moisture content. The best of these equations are found to be significantly more accurate than current procedures for adjusting estimates of strength properties such as MOR and RS. Because MOE and EI are less affected by changes in moisture content, most of the equations work well for these properties

    Understanding pregnancy planning in a low-income country setting: validation of the London measure of unplanned pregnancy in Malawi

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    This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: The London Measure of Unplanned Pregnancy (LMUP) is a new and psychometrically valid measure of pregnancy intention that was developed in the United Kingdom. An improved understanding of pregnancy intention in low-income countries, where unintended pregnancies are common and maternal and neonatal deaths are high, is necessary to inform policies to address the unmet need for family planning. To this end this research aimed to validate the LMUP for use in the Chichewa language in Malawi.Methods: Three Chichewa speakers translated the LMUP and one translation was agreed which was back-translated and pre-tested on five pregnant women using cognitive interviews. The measure was field tested with pregnant women who were recruited at antenatal clinics and data were analysed using classical test theory and hypothesis testing.Results: 125 women aged 15-43 (median 23), with parities of 1-8 (median 2) completed the Chichewa LMUP. There were no missing data. The full range of LMUP scores was captured. In terms of reliability, the scale was internally consistent (Cronbach's alpha = 0.78) and test-retest data from 70 women showed good stability (weighted Kappa 0.80). In terms of validity, hypothesis testing confirmed that unmarried women (p = 0.003), women who had four or more children alive (p = 0.0051) and women who were below 20 or over 29 (p = 0.0115) were all more likely to have unintended pregnancies. Principal component analysis showed that five of the six items loaded onto one factor, with a further item borderline. A sensitivity analysis to assess the effect of the removal of the weakest item of the scale showed slightly improved performance but as the LMUP was not significantly adversely affected by its inclusion we recommend retaining the six-item score.Conclusion: The Chichewa LMUP is a valid and reliable measure of pregnancy intention in Malawi and can now be used in research and/or surveillance. This is the first validation of this tool in a low-income country, helping to demonstrate that the concept of pregnancy planning is applicable in such a setting. Use of the Chichewa LMUP can enhance our understanding of pregnancy intention in Malawi, giving insight into the family planning services that are required to better meet women's needs and save lives. © 2013 Hall et al.; licensee BioMed Central Ltd.Dr Hall’s Wellcome Trust Research Training Fellowship, grant number 097268/Z/11/Z

    Molecular Responses to Thermal and Osmotic Stress in Arctic Intertidal Mussels (Mytilus edulis): The Limits of Resilience.

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    Increases in Arctic temperatures have accelerated melting of the Greenland icesheet, exposing intertidal organisms, such as the blue mussel Mytilus edulis, to high air temperatures and low salinities in summer. However, the interaction of these combined stressors is poorly described at the transcriptional level. Comparing expression profiles of M. edulis from experimentally warmed (30 °C and 33 °C) animals kept at control (23‱) and low salinities (15‱) revealed a significant lack of enrichment for Gene Ontology terms (GO), indicating that similar processes were active under all conditions. However, there was a progressive increase in the abundance of upregulated genes as each stressor was applied, with synergistic increases at 33 °C and 15‱, suggesting combined stressors push the animal towards their tolerance thresholds. Further analyses comparing the effects of salinity alone (23‱, 15‱ and 5‱) showed high expression of stress and osmoregulatory marker genes at the lowest salinity, implying that the cell is carrying out intracellular osmoregulation to maintain the cytosol as hyperosmotic. Identification of aquaporins and vacuolar-type ATPase transcripts suggested the cell may use fluid-filled cavities to excrete excess intracellular water, as previously identified in embryonic freshwater mussels. These results indicate that M. edulis has considerable resilience to heat stress and highly efficient mechanisms to acclimatise to lowered salinity in a changing world

    'Transcriptional differentiation of Trypanosoma brucei during in vitro acquisition of resistance to acoziborole

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    Subspecies of the protozoan parasite Trypanosoma brucei are the causative agents of Human African Trypanosomiasis (HAT), a debilitating neglected tropical disease prevalent across sub-Saharan Africa. HAT case numbers have steadily decreased since the start of the century, and sustainable elimination of one form of the disease is in sight. However, key to this is the development of novel drugs to combat the disease. Acoziborole is a recently developed benzoxaborole, currently in advanced clinical trials, for treatment of stage 1 and stage 2 HAT. Importantly, acoziborole is orally bioavailable, and curative with one dose. Recent studies have made significant progress in determining the molecular mode of action of acoziborole. However, less is known about the potential mechanisms leading to acoziborole resistance in trypanosomes. In this study, an in vitro-derived acoziborole-resistant cell line was generated and characterised. The Aco(R) line exhibited significant cross-resistance with the methyltransferase inhibitor sinefungin as well as hypersensitisation to known trypanocides. Interestingly, transcriptomics analysis of Aco(R) cells indicated the parasites had obtained a procyclic- or stumpy-like transcriptome profile, with upregulation of procyclin surface proteins as well as differential regulation of key metabolic genes known to be expressed in a life cycle-specific manner, even in the absence of major morphological changes. However, no changes were observed in transcripts encoding CPSF3, the recently identified protein target of acoziborole. The results suggest that generation of resistance to this novel compound in vitro can be accompanied by transcriptomic switches resembling a procyclic- or stumpy-type phenotype

    Use of bisulfite processing to generate high-β-O-4 content water-soluble lignosulfonates

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    This work was supported by EPSRC grants (EP/1518175), the Industrial Biotechnology Innovation Centre (IBioIC) (DMB Ph.D. studentship) and an EPSRC Doctoral Prize Fellowship (CSL).With lignin-first biorefineries likely to become a reality, controlled depolymerization of high-quality lignin streams to high value products has become a priority. Using bisulfite chemistry, access to a high-β-O-4 content water-soluble lignosulfonate has been achieved, allowing follow-on procedures in water to be conducted. We show that phenolic β-O-4 units preferential-ly react under acidic bisulfite conditions, whilst non-phenolic β-O-4 units react much more slowly. Exploiting this improved chemical understanding and inherent selectivity, a softwood lignosulfonate has been prepared in which phenolic β-O-4 α-sulfonation has occurred leaving significant native β-O-4 content. Use of an O-benzoylation protocol with lignin coupled with advanced 2D NMR methods has allowed detailed analysis of this and other commercial and industrial lignosulfonates. Conversion of the native β-O-4 to benzylic- oxidized β-O-4 units was followed by a selective reductive cleavage to give a premium aromatic monomer in pure form.Publisher PDFPeer reviewe
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