5,292 research outputs found

    Impacts of Co-Solvent Flushing on Microbial Populations Capable of Degrading Trichloroethylene

    Get PDF
    With increased application of co-solvent flushing technologies for removal of nonaqueous phase liquids from groundwater aquifers, concern over the effects of the solvent on native microorganisms and their ability to degrade residual contaminant has also arisen. This study assessed the impact of ethanol flushing on the numbers and activity potentials of trichloroethylene (TCE)-degrading microbial populations present in aquifer soils taken immediately after and 2 years after ethanol flushing of a former dry cleaners site. Polymerase chain reaction analysis revealed soluble methane monooxygenase genes in methanotrophic enrichments, and 16S rRNA analysis identified Methylocystis parvus with 98% similarity, further indicating the presence of a type II methanotroph. Dissimilatory sulfite reductase genes in sulfate-reducing enrichments prepared were also observed. Ethanol flushing was simulated in columns packed with uncontaminated soils from the dry cleaners site that were dosed with TCE at concentrations observed in the field; after flushing, the columns were subjected to a continuous flow of 500 pore volumes of groundwater per week. Total acridine orange direct cell counts of the flushed and nonflushed soils decreased over the 15-week testing period, but after 5 weeks, the flushed soils maintained higher cell counts than the nonflushed soils. Inhibition of methanogenesis by sulfate reduction was observed in all column soils, as was increasing removal of total methane by soils incubated under methanotrophic conditions. These results showed that impacts of ethanol were not as severe as anticipated and imply that ethanol may mitigate the toxicity of TCE to the microorganisms

    Mapping Atlantic rainforest degradation and regeneration history with indicator species using convolutional network

    Get PDF
    The Atlantic rainforest of Brazil is one of the global terrestrial hotspots of biodiversity. Despite having undergone large scale deforestation, forest cover has shown signs of increases in the last decades. Here, to understand the degradation and regeneration history of Atlantic rainforest remnants near São Paulo, we combine a unique dataset of very high resolution images from Worldview-2 and Worldview-3 (0.5 and 0.3m spatial resolution, respectively), georeferenced aerial photographs from 1962 and use a deep learning method called U-net to map (i) the forest cover and changes and (ii) two pioneer tree species, Cecropia hololeuca and Tibouchina pulchra. For Tibouchina pulchra, all the individuals were mapped in February, when the trees undergo mass-flowering with purple and pink blossoms. Additionally, elevation data at 30m spatial resolution from NASA Shuttle Radar Topography Mission (SRTM) and annual mean climate variables (Terraclimate datasets at ∼ 4km of spatial resolution) were used to analyse the forest and species distributions. We found that natural forests are currently more frequently found on south-facing slopes, likely because of geomorphology and past land use, and that Tibouchina is restricted to the wetter part of the region (southern part), which annually receives at least 1600 mm of precipitation. Tibouchina pulchra was found to clearly indicate forest regeneration as almost all individuals were found within or adjacent to forests regrown after 1962. By contrast, Cecropia hololeuca was found to indicate older disturbed forests, with all individuals almost exclusively found in forest fragments already present in 1962. At the regional scale, using the dominance maps of both species, we show that at least 4.3% of the current region’s natural forests have regrown after 1962 (Tibouchina dominated, ∼ 4757 ha) and that ∼ 9% of the old natural forests have experienced significant disturbance (Cecropia dominated)

    Different Imaging Strategies in Patients With Possible Basilar Artery Occlusion Cost-Effectiveness Analysis

    Get PDF
    Background and Purpose-This study evaluated the cost-effectiveness of different noninvasive imaging strategies in patients with possible basilar artery occlusion. Methods-A Markov decision analytic model was used to evaluate long-term outcomes resulting from strategies using computed tomographic angiography (CTA), magnetic resonance imaging, nonenhanced CT, or duplex ultrasound with intravenous (IV) thrombolysis being administered after positive findings. The analysis was performed from the societal perspective based on US recommendations. Input parameters were derived from the literature. Costs were obtained from United States costing sources and published literature. Outcomes were lifetime costs, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios, an

    Adherence to Tuberculosis Therapy among Patients Receiving Home-Based Directly Observed Treatment: Evidence from the United Republic of Tanzania.

    Get PDF
    \ud \ud Non-adherence to tuberculosis (TB) treatment is the leading contributor to the selection of drug-resistant strains of Mycobacterium tuberculosis and subsequent treatment failure. Tanzania introduced a TB Patient Centred Treatment (PCT) approach which gives new TB patients the choice between home-based treatment supervised by a treatment supporter of their own choice, and health facility-based treatment observed by a medical professional. The aim of this study was to assess the extent and determinants of adherence to anti-TB therapy in patients opting for home-based treatment under the novel PCT approach. In this cross-sectional study, the primary outcome was the percentage of patients adherent to TB therapy as detected by the presence of isoniazid in urine (IsoScreen assay). The primary analysis followed a non-inferiority approach in which adherence could not be lower than 75%. Logistic regression was used to examine the influence of potentially predictive factors. A total of 651 new TB patients were included. Of these, 645 (99.1%) provided urine for testing and 617 patients (95.7%; 90%CI 94.3-96.9) showed a positive result. This result was statistically non-inferior to the postulated adherence level of 75% (p<0.001). Adherence to TB therapy under home-based Directly Observed Treatment can be ensured in programmatic settings. A reliable supply of medication and the careful selection of treatment supporters, who preferably live very close to the patient, are crucial success factors. Finally, we recommend a cohort study to assess the rate of adherence throughout the full course of TB treatment

    Seksueel overdraagbare aandoeningen, waaronder HIV, in Nederland in 2007

    Get PDF
    Net als in 2006 was chlamydia in 2007 de meest gediagnosticeerde bacterikle geslachtsziekte in de soacentra, vooral bij jongeren. Het percentage positieve chlamydiatesten nder heteroseksuele mannen en vrouwen daalde enigszins, voor het eerst sinds vier jaar (van 10,6% naar 10,1%). In 2006 stabiliseerde dit percentage bij mannen die seks hebben met mannen (MSM), en die trend zette door in 2007. Het percentage positieve gonorroe-, syfilis- en hivtesten nam net als voorgaande jaren af in 2007 (respectievelijk 2,4%, 0,9% en ,5%). Deze infecties werden het meest gediagnosticeerd bij MSM. In 2007 zijn er 306 nieuwe hivdiagnoses gesteld in de soacentra, ongeveer een derde van de 864 hivpositieven die dat jaar landelijk in de hivcentra zijn gemeld. Eind 2007 waren in totaal 14.019 personen in Nederland met hiv geregistreerd. Het aandeel van MSM onder de nieuw hivinfecties nam in 2007 verder toe. Net als eerdere jaren werd in de soacentra bij MSM die bekend zijn met hun positieve hivstatus vaak nog een andere geslachtsziekte gevonden (45%). In deze groep is sinds 2004 regelmatig LGV, een agressieve variant van chlamydia, en sinds 2007 hepatitis C gediagnosticeerd. Versterkte surveillance en innovatieve interventies zijn nodig om verdere verspreiding onder MSM en naar andere groepen te voorkomen. Onder bepaalde migrantengroepen in Nederland (onder andere afkomstig uit Suriname, de Nederlandse Antillen en Aruba) komen hiv, chlamydia, gonorroe en syfilis relatief vaker voor dan onder autochtone Nederlanders. Ook deze constatering vraagt om vernieuwende maatregelen die op de bevolkingsgroepen zijn toegespitst. De soacentra bieden soazorg aan hoogrisicogroepen. In 2007 hebben ruim 78.000 personen zich daar laten testen, een toename van 13% ten opzichte van 2006. Net als in 2006 was chlamydia in 2007 de meest gediagnosticeerde bacterikle geslachtsziekte in de soacentra, vooral bij jongeren. Het percentage positieve chlamydiatesten onder heteroseksuele mannen en vrouwen daalde enigszins, voor het eerst sinds vier jaar (van 10,6% naar 10,1%). In 2006 stabiliseerde dit percentage bij mannen die seks hebben met mannen (MSM), en die trend zette door in 2007. Het percentage positieve gonorroe-, syfilis- en hivtesten nam net als voorgaande jaren af in 2007 (respectievelijk 2,4%, 0,9% en 0,5%). Deze infecties werden het meest gediagnosticeerd bij MSM.In 2007, chlamydia was the most common bacterial sexually transmitted infection (STI) diagnosed in Dutch STI centres. Similar to previous years, infections were reported especially in young heterosexuals. The proportion of positive chlamydia tests among heterosexual men and women decreased slightly for the first time in four years (from 10.6% to 10.1%). In 2006, this proportion had stabilized in men who have sex with men (MSM) with the trend continuing in 2007. The positivity rate for gonorrhoea (2.4%), syphilis (0.9%) and HIV (0.5%) continued to decrease in 2007. These infections were most frequently diagnosed in MSM. In 2007, 306 new positive HIV cases were diagnosed in STI centres in the Netherlands. This number amounts to about one third of the total number of 864 positive HIV cases registered nationally. At the end of 2007, a total of 14,019 HIV cases in care were registered in the Netherlands. The proportion of MSM among new HIV cases rose further in 2007. In line with previous years, concurrent STIs were diagnosed very frequently among MSM visiting STI centres (45%) who had known HIV positive status. In this group of men, Lymphogranuloma Venereum (LGV) an aggressive type of chlamydia, has been reported frequently since 2004; this has also been the case for hepatitis C since 2007. In this group of men, strengthened surveillance and innovative interventions are warranted in order to prevent further transmission both among MSM and to other population groups. In some specific migrant groups in the Dutch population -- for example, people from Surinam, the Netherlands Antilles and Aruba -- HIV, chlamydia, gonorrhoea and syphilis are more common than in the autochthonous Dutch population. This indicates the need for targeted intervention by risk profile. The specialised STI centres in the Netherlands offer STI testing and care targeted at high risk groups. In 2007, approximately 78,000 people used this service amounting to a rise of 13% compared to 2006

    Estimation of the solubility parameters of model plant surfaces and agrochemicals: a valuable tool for understanding plant surface interactions

    Get PDF
    Background Most aerial plant parts are covered with a hydrophobic lipid-rich cuticle, which is the interface between the plant organs and the surrounding environment. Plant surfaces may have a high degree of hydrophobicity because of the combined effects of surface chemistry and roughness. The physical and chemical complexity of the plant cuticle limits the development of models that explain its internal structure and interactions with surface-applied agrochemicals. In this article we introduce a thermodynamic method for estimating the solubilities of model plant surface constituents and relating them to the effects of agrochemicals. Results Following the van Krevelen and Hoftyzer method, we calculated the solubility parameters of three model plant species and eight compounds that differ in hydrophobicity and polarity. In addition, intact tissues were examined by scanning electron microscopy and the surface free energy, polarity, solubility parameter and work of adhesion of each were calculated from contact angle measurements of three liquids with different polarities. By comparing the affinities between plant surface constituents and agrochemicals derived from (a) theoretical calculations and (b) contact angle measurements we were able to distinguish the physical effect of surface roughness from the effect of the chemical nature of the epicuticular waxes. A solubility parameter model for plant surfaces is proposed on the basis of an increasing gradient from the cuticular surface towards the underlying cell wall. Conclusions The procedure enabled us to predict the interactions among agrochemicals, plant surfaces, and cuticular and cell wall components, and promises to be a useful tool for improving our understanding of biological surface interactions

    The WASh Trial: water-assisted sigmoidoscopy in the English Bowel Scope Screening Programme: study protocol for a randomized multicenter trial

    Get PDF
    Background and study aims:  The English National Bowel Scope Screening Programme (BSSP) invites 55-year-olds for a one-off, unsedated flexible sigmoidoscopy (FSIG). Data from BSSP participant-reported experience studies shows 1 in 3 participants report moderate or severe discomfort. Water-assisted colonoscopy (WAS) may improve participants' comfort. The primary objective of this study is to ascertain if post-procedural participant-assessed pain is reduced in WAS compared with carbon dioxide (CO 2 ) insufflation, in invitees undergoing FSIG in BSSP. Patients and methods  This is a multicenter, prospective, randomized, two-arm, single-blinded trial designed to evaluate the performance of WAS versus CO 2 insufflation in BSSP. Participants will be randomized to either CO 2 or WAS and will be asked to rate pain post-procedure. Key procedure-related data will be analyzed, including adenoma detection rates (ADR) and degree of sigmoid looping. A cost-effectiveness analysis of WAS versus CO 2 and a discrete choice experiment exploring preferences of participants for attributes of sigmoidoscopy will also be performed. Discussion  This is the first trial in the United Kingdom (UK) to investigate the effects of WAS in a screening setting. If the trial shows WAS either reduces pain or increases ADR, this may result in a practice change to implement WAS in screening and non-screening endoscopic practice directly impacting on 256,000 people a year who will undergo BSSP FSIG by 2020. Trial funding came from National Institute for Health Research (NIHR) Research for Patient Benefit (RfPB) supported by the NIHR Clinical Research Network. The trial is actively recruiting. ID: 35866 ISRCTN: 81466870

    Modelling and simulating change in reforesting mountain landscapes using a social-ecological framework

    Get PDF
    Natural reforestation of European mountain landscapes raises major environmental and societal issues. With local stakeholders in the Pyrenees National Park area (France), we studied agricultural landscape colonisation by ash (Fraxinus excelsior) to enlighten its impacts on biodiversity and other landscape functions of importance for the valley socio-economics. The study comprised an integrated assessment of land-use and land-cover change (LUCC) since the 1950s, and a scenario analysis of alternative future policy. We combined knowledge and methods from landscape ecology, land change and agricultural sciences, and a set of coordinated field studies to capture interactions and feedback in the local landscape/land-use system. Our results elicited the hierarchically-nested relationships between social and ecological processes. Agricultural change played a preeminent role in the spatial and temporal patterns of LUCC. Landscape colonisation by ash at the parcel level of organisation was merely controlled by grassland management, and in fact depended on the farmer's land management at the whole-farm level. LUCC patterns at the landscape level depended to a great extent on interactions between farm household behaviours and the spatial arrangement of landholdings within the landscape mosaic. Our results stressed the need to represent the local SES function at a fine scale to adequately capture scenarios of change in landscape functions. These findings orientated our modelling choices in the building an agent-based model for LUCC simulation (SMASH - Spatialized Multi-Agent System of landscape colonization by ASH). We discuss our method and results with reference to topical issues in interdisciplinary research into the sustainability of multifunctional landscapes

    Interventricular septum hematoma during cineventriculography

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Intraseptal hematoma and subsequent myocardial infarction due to accidental contrast agent deposition complicating diagnostic cineventriculography is a previously undescribed complication of angiography.</p> <p>Case presentation</p> <p>A 61 year old man was admitted at intensive care unit because of unstable angina pectoris 1 hour after coronary angiography. Transthoracic contrast echocardiography showed a non-perfused area in the middle of interventricular septum with an increase of thickening up to 26 mm. Review of cineventriculography revealed contrast enhancement in the interventricular septum after contrast medium injection and a dislocation of the pigtail catheter tip. Follow up by echocardiography and MRI showed, that intramural hematoma has resolved after 6 weeks. After 8 weeks successful stent implantation in LAD was performed and after 6 month the patient had a normal LV-function without ischemic signs or septal thickening demonstrated by stressechocardiography.</p> <p>Conclusion</p> <p>A safe and mobile position of the pigtail catheter during ventriculography in the middle of the LV cavity should be ensured to avoid this potentially life-threatening complication. For assessment and absolute measurement of intramural hematoma contrast-enhanced echocardiography is more feasible than MRI and makes interchangeable results.</p
    corecore