35 research outputs found

    Toxicity assessment of individual ingredients of synthetic-based drilling muds (SBMs)

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    Synthetic-based drilling muds (SBMs) offer excellent technical characteristics while providing improved environmental performance over other drilling muds. The low acute toxicity and high biodegradability of SBMs suggest their discharge at sea would cause minimal impacts on marine ecosystems, however, chronic toxicity testing has demonstrated adverse effects of SBMs on fish health. Sparse environmental monitoring data indicate effects of SBMs on bottom invertebrates. However, no environmental toxicity assessment has been performed on fish attracted to the cutting piles. SBM formulations are mostly composed of synthetic base oils, weighting agents, and drilling additives such as emulsifiers, fluid loss agents, wetting agents, and brine. The present study aimed to evaluate the impact of exposure to individual ingredients of SBMs on fish health. To do so, a suite of biomarkers [ethoxyresorufin-O-deethylase (EROD) activity, biliary metabolites, sorbitol dehydrogenase (SDH) activity, DNA damage, and heat shock protein] have been measured in pink snapper (Pagrus auratus) exposed for 21 days to individual ingredients of SBMs. The primary emulsifier (Emul S50) followed by the fluid loss agent (LSL 50) caused the strongest biochemical responses in fish. The synthetic base oil (Rheosyn) caused the least response in juvenile fish. The results suggest that the impact of Syndrill 80:20 on fish health might be reduced by replacement of the primary emulsifier Emul S50 with an alternative ingredient of less toxicity to aquatic biota. The research provides a basis for improving the environmental performance of SBMs by reducing the environmental risk of their discharge and providing environmental managers with information regarding the potential toxicity of individual ingredients. © 2011 Springer Science+Business Media B.V

    Challenges to access and provision of palliative care for people who are homeless : a systematic review of qualitative research

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    Background: People who are homeless or vulnerably housed are a marginalized group who often experience high rates of morbidity and die young as a result of complex problems. Access to health care and support can be challenging, with access to palliative care even more so. This review presents a synthesis of published qualitative research exploring from the perspective of homeless people and those working to support them, current challenges to palliative care access and provision, in addition to suggestions for what may improve palliative care for this population. Methods: Systematic review of qualitative research analysed using thematic synthesis. PsycINFO, Medline, Sociological Abstracts, Social Services Abstracts, Science citations index and CINAHL were searched up to September 2016. Thematic synthesis involved a three-step inductive process to develop a deeper understanding of the challenges to and suggestions for the access and provision of palliative care for homeless people. Results: Thirteen qualitative articles, reporting nine studies were identified. The challenges to access and provision to palliative care were drawn from the data covering three broad areas, namely “the chaotic lifestyles sometimes associated with being homeless”, “the delivery of palliative care within a hostel for homeless people” and provision within “mainstream health care systems”. Obstacles were related to homeless persons competing day-to-day priorities, their experience of stigma in mainstream settings, the high burden on hostel staff in supporting residents at the end of life and inflexibility in mainstream health care systems. Suggestions for improving access to palliative care include building trust between homeless persons and health professionals, increasing collaboration between and flexibility within services, and providing more training and support for all professionals. Conclusions: The provision of palliative care can be complicated for all populations, however delivering palliative care for people who are homeless is influenced by a potentially greater and more varied range of factors, on both individual and systemic levels, than providing palliative care for the housed population. Careful consideration and potentially great changes will be needed within health care systems to ensure homeless populations have equitable access to palliative care

    A pragmatic observational feasibility study on integrated treatment for musculoskeletal disorders: design and protocol

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    Background: Musculoskeletal disorders (MSD) comprise a wide range of conditions, associated with an enormous pain and impaired mobility, and are affecting people's lives and work. Management of musculoskeletal disorders typically involves a multidisciplinary team approach. Positive findings have been found in previous studies evaluating the effectiveness of complementary therapies, though little attention has been paid to evaluating of the effectiveness of integrated packages of care combining conventional and complementary approaches for musculoskeletal conditions in a National Health Service (NHS) setting. Objective: To determine the feasibility of all aspects of a pragmatic observational study designed: (1) to evaluate the effectiveness and cost effectiveness of integrated treatments for MSDs in an integrated NHS hospital in the UK; (2) to determine the acceptability of the study design and research process to patients; (3) to explore patients' expectation and experience of receiving integrated treatments. Methods: This is an observational feasibility study, with 1-year recruitment and 1-year follow-up, conducted in Royal London Hospital for Integrated Medicine, University College London Hospital Trust, UK. All eligible patients with MSDs newly referred to the hospital were included in the study. Interventions are integrated packages of care (conventional and complementary) as currently provided in the hospital. SF-36™ Health Survey, short form Brief Pain Inventory, Visual Analogue Scale, and modified Client Service Receipt Inventory will be assessed at 4/5 time points. Semi-structured interview/focus group will be carried out before treatment, and 1 year after commence of treatment. Discussion: We intend to conduct a pragmatic observational study of integrated medical treatment of MSDs at a public sector hospital. It will inform the design of a future trial including recruitment, retention, suitability of the outcome measures and patients experiences

    Vascular development in plants: specification of xylem and phloem tissues

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    The plant vascular system is a complicated network of conducting tissues that interconnects all organs and transports water, minerals, organic compounds, and various signaling molecules throughout the entire organism. This system is composed of two major tissue types - xylem and phloem - that originate from the vascular meristem, i.e., the procambium. Recently, combined applications of molecular genetics and genomics tools have provided significant insights into the underlying mechanisms by which specification of these two types are regulated. They include 1) the asymmetric patterning of xylem and phloem in the vascular bundle that arises through antagonistic functioning between the HD-ZIP III and KANADI transcription factors, 2) control of vascular cell proliferation by brassinosteroids (BRs) and the HD-ZIP III transcription factors, and 3) regulation of vascular tissue identity by the MYB transcription factor APL and the NAC transcription factors VND6 and VND7. These findings define an emerging developmental framework for the control of vascular tissue specification.N

    The Internal Critical Level Concept of Nonspecific Toxicity

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    miR398 and miR408 are up-regulated in response to water deficit in Medicago truncatula

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    Plant microRNAs have been implicated in various abiotic stress responses. We identified several conserved microRNAs that showed differential expression in Medicago truncatula plants subjected to water deficit: miR169 is down-regulated only in the roots and miR398a/b and miR408 are strongly up-regulated in both shoots and roots. Down-regulation of miR169 in the roots did not correlate with accumulation of its target MtHAP2-1 transcripts, suggesting that its regulation may not occur at the mRNA level or may depend on other regulatory mechanisms, which do not involve this miRNA, in water-deficit conditions. The up-regulation of miR398a/b and miR408 and the clear down-regulation of their respective target genes, which encode the copper proteins COX5b (subunit 5b of mitochondrial cytochrome c oxidase) and plantacyanin, highlight the involvement of these miRNAs in response to water deprivation in M. truncatula. Also, miR398 up-regulation is inversely correlated with the down-regulation of copper superoxide dismutase, CSD1, during water deficit. The regulation of genes encoding copper proteins by miR398a/b and miR408 suggests a link between copper homeostasis and M. truncatula adaptation to progressive water deficit

    An Arabidopsis gene regulatory network for secondary cell wall synthesis

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    The plant cell wall is an important factor for determining cell shape, function and response to the environment. Secondary cell walls, such as those found in xylem, are composed of cellulose, hemicelluloses and lignin and account for the bulk of plant biomass. The coordination between transcriptional regulation of synthesis for each polymer is complex and vital to cell function. A regulatory hierarchy of developmental switches has been proposed, although the full complement of regulators remains unknown. Here we present a protein–DNA network between Arabidopsis thaliana transcription factors and secondary cell wall metabolic genes with gene expression regulated by a series of feed-forward loops. This model allowed us to develop and validate new hypotheses about secondary wall gene regulation under abiotic stress. Distinct stresses are able to perturb targeted genes to potentially promote functional adaptation. These interactions will serve as a foundation for understanding the regulation of a complex, integral plant component
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