34 research outputs found

    Liquid Phase Hydrodechlorination of Dieldrin and DDT over Pd/C and Raney-Ni

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    Selectivity and product distribution of hydrodechlorination (HDCl) of dieldrin and DDT are studied in different liquid phase systems, namely in: (1) in ethanol; and (2) in the supported ionic liquid heterogeneous catalytic system (multiphase system), composed by the organic phase and aqueous KOH, a quaternary ammonium ionic liquid promoter (Aliquat 336), and a metal catalyst, e.g. 5% Pd/C, 5% Pt/C, or Raney-Ni. At 50 8C and atmospheric pressure of hydrogen, a quantitative hydrodechlorination of DDT in the biphasic system with ionic liquid layer is achieved in 40 min and in 4 h with Raney-Ni and Pd/C, respectively, while the reaction on Pt/C or on Pd/C without Aliquat 336 is slow. Dieldrin undergoes partial dechlorination, with high selectivity achievable only for its mono- and bi-dechlorination products. Dechlorination pathways and reactivity of different types of organic chlorine atoms versus the catalyst nature and other conditions are discussed

    Seasonal and spatial variability in plankton production and respiration in the Subtropical Gyres of the Atlantic Ocean

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    Euphotic zone plankton production (P) and respiration (R) were determined from the in vitro flux of dissolved oxygen during six latitudinal transects of the Atlantic Ocean, as part of the Atlantic Meridional Transect (AMT) programme. The transects traversed the North and South Atlantic Subtropical Gyres (N gyre, 18–38°N; S gyre, 11–35°S) in April–June and September–November 2003–2005. The route and timing of the cruises enabled the assessment of the seasonal variability of P, R and P/R in the N and S gyres, and the comparison of the previously unsampled N gyre centre with the more frequently sampled eastern edge of the gyre. Mean euphotic zone integrated rates (±SE) were P=63±23 (n=31), R=69±22 (n=30) mmol O2 m-2 d-1 in the N gyre; and P=58±26 (n=30), R=62±24 (n=30) mmol O2 m-2 d-1 in the S gyre. Overall, the N gyre was heterotrophic (R>P) and it was more heterotrophic than the S gyre, but the metabolic balance of both gyres changed with season. Both gyres were net heterotrophic in autumn, and balanced in spring. This seasonal contrast was most pronounced for the S gyre, because it was more autotrophic than the N gyre during spring. This may have arisen from differences in nitrate availability, because spring sampling in the S gyre coincided with periods of deep mixing to the nitracline, more frequently than spring sampling within the N gyre. Our results indicate that the N gyre is less heterotrophic than previous estimates suggested, and that there is an apparent decrease in R from the eastern edge to the centre of the N gyre, possibly indicative of an allochthonous organic carbon source to the east of the gyre

    Reporting animal research:Explanation and elaboration for the ARRIVE guidelines 2.0

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    Improving the reproducibility of biomedical research is a major challenge. Transparent and accurate reporting is vital to this process; it allows readers to assess the reliability of the findings and repeat or build upon the work of other researchers. The ARRIVE guidelines (Animal Research: Reporting In Vivo Experiments) were developed in 2010 to help authors and journals identify the minimum information necessary to report in publications describing in vivo experiments. Despite widespread endorsement by the scientific community, the impact of ARRIVE on the transparency of reporting in animal research publications has been limited. We have revised the ARRIVE guidelines to update them and facilitate their use in practice. The revised guidelines are published alongside this paper. This explanation and elaboration document was developed as part of the revision. It provides further information about each of the 21 items in ARRIVE 2.0, including the rationale and supporting evidence for their inclusion in the guidelines, elaboration of details to report, and examples of good reporting from the published literature. This document also covers advice and best practice in the design and conduct of animal studies to support researchers in improving standards from the start of the experimental design process through to publication

    Children must be protected from the tobacco industry's marketing tactics.

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    Tropical Data: Approach and Methodology as Applied to Trachoma Prevalence Surveys

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    PURPOSE: Population-based prevalence surveys are essential for decision-making on interventions to achieve trachoma elimination as a public health problem. This paper outlines the methodologies of Tropical Data, which supports work to undertake those surveys. METHODS: Tropical Data is a consortium of partners that supports health ministries worldwide to conduct globally standardised prevalence surveys that conform to World Health Organization recommendations. Founding principles are health ministry ownership, partnership and collaboration, and quality assurance and quality control at every step of the survey process. Support covers survey planning, survey design, training, electronic data collection and fieldwork, and data management, analysis and dissemination. Methods are adapted to meet local context and needs. Customisations, operational research and integration of other diseases into routine trachoma surveys have also been supported. RESULTS: Between 29th February 2016 and 24th April 2023, 3373 trachoma surveys across 50 countries have been supported, resulting in 10,818,502 people being examined for trachoma. CONCLUSION: This health ministry-led, standardised approach, with support from the start to the end of the survey process, has helped all trachoma elimination stakeholders to know where interventions are needed, where interventions can be stopped, and when elimination as a public health problem has been achieved. Flexibility to meet specific country contexts, adaptation to changes in global guidance and adjustments in response to user feedback have facilitated innovation in evidence-based methodologies, and supported health ministries to strive for global disease control targets

    Bilateral tibial tuberosity advancement and medial patellar luxation repair in a one-year-old mixed breed dog

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    A one-year-old spayed female mixed breed dog presented to the Cornell University Hospital for Animals Orthopedics service in January 2012, for left hind limb lameness. The lameness had begun suddenly one month earlier while the patient was playing with other dogs, and it recurred after exercise or long periods of rest. She also had a three-month history of medial patellar luxation in her right hind limb that had never previously been treated. On presentation, the patient was ambulatory on all four limbs with no gait abnormalities or visible lameness. Orthopedic examination revealed bilateral positive cranial drawer signs, bilateral tibial thrust, bilateral Ortolani signs, a grade 2 medial patellar luxation in her right hind limb, and a grade 1 medial patellar luxation in her left hind limb. Lateral stifle radiographs were obtained but revealed no abnormalities. However, based on physical examination, bilateral cranial cruciate ligament rupture and bilateral medial patellar luxation were presumptively diagnosed. The patient’s owner elected to pursue surgical treatment rather than attempting conservative management. Bilateral tibial tuberosity transposition advancement with lateral imbrication was performed to simultaneously correct the medial patellar luxation and presumptive cranial cruciate ligament rupture. This paper will discuss the diagnosis, surgical treatment, recovery, and prognosis of both cranial cruciate ligament rupture and medial patellar luxation

    Treatment coverage surveys as part of a trachoma control programme

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    One of the pillars of the SAFE strategy for trachoma control is the use of mass drug administration (MDA) using azithromycin (Zithromax®) donated by Pfizer Inc. Azithromycin is very effective for curing infections with ocular Chlamydia trachomatis with a single oral dose. Unusually for the administration of antibiotics, MDA is offered to all members of a defined population without first making an individual diagnosis for each recipient. This is done, in part, because the clinical signs of trachoma do not always mean that C. trachomatis is present and an accurate test for infection is costly and time-consuming to conduct. As a result, members of a defined population (the ‘target population’) are offered treatment whether they have a confirmed current infection or not
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