694 research outputs found

    Water quality effects of intermittent water supply in ArraijƔn, Panama

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    Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause waterquality to degrade in the distribution system.In this study,we characterized waterquality in one study zone with continuous supply and three zoneswith intermittentsupply in the drinking waterdistribution network in Arraija!n,Panama.Low orzero pressuresoccurred in allzones,and negative pressuresoccurred in the continuouszone and two ofthe intermittentzones.Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samplescollected atrandom timeswere positive fortotalcoliform bacteria and only one waspositive for E.coli.Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had !0.2 mg/L free chlorine residual.In contrast,water quality was often degraded during the first-flush period (when supply first returned after an outage).Still, routine and first-flush water quality under intermittent supply was much better in Arraija!n than that reported in a previous study conducted in India.Better waterquality in Arraija!n could be due to betterwaterquality leaving the treatmentplant,shortersupply outages,highersupply pressures,a more consistentand higherchlorine residual,and fewercontaminant sourcesnearpipes.The resultsillustrate thatintermittentsupply and itseffectson waterquality can vary greatly between and within distribution networks.The study also demonstrated thatmonitoring techniques designed specifically for intermittentsupply,such as continuous pressure monitoring and sampling the firstflush,can detectwaterquality threats and degradation thatwould notlikely be detected with conventionalmonitoring.Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause waterquality to degrade in the distribution system.In this study,we characterized waterquality in one study zone with continuous supply and three zoneswith intermittentsupply in the drinking waterdistribution network in Arraija!n,Panama.Low orzero pressuresoccurred in allzones,and negative pressuresoccurred in the continuouszone and two ofthe intermittentzones.Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samplescollected atrandom timeswere positive fortotalcoliform bacteria and only one waspositive for E.coli.Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had !0.2 mg/L free chlorine residual.In contrast,water quality was often degraded during the first-flush period (when supply first returned after an outage).Still, routine and first-flush water quality under intermittent supply was much better in Arraija!n than that reported in a previous study conducted in India.Better waterquality in Arraija!n could be due to betterwaterquality leaving the treatmentplant,shortersupply outages,highersupply pressures,a more consistentand higherchlorine residual,and fewercontaminant sourcesnearpipes.The resultsillustrate thatintermittentsupply and itseffectson waterquality can vary greatly between and within distribution networks.The study also demonstrated thatmonitoring techniques designed specifically for intermittentsupply,such as continuous pressure monitoring and sampling the firstflush,can detectwaterquality threats and degradation thatwould notlikely be detected with conventionalmonitoring

    The influence of left ventricular hypertrophyon survival in patients with coronaryartery disease: do race and gender matter?

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    AbstractObjectivesWe sought to determine the overall prognostic importance of left ventricular hypertrophy (LVH) among patients with coronary artery disease (CAD), as well as to determine whether this risk varies as a function of race or gender.BackgroundLeft ventricular hypertrophy is more prevalent among blacks and women than their counterparts. Blacks and women also have higher mortality with coronary disease.MethodsWe studied records of 2,461 patients (19% black, 42% women) diagnosed with CAD at cardiac catheterization between 1990 and 1998 from a single academic center. Left ventricular hypertrophy was defined using standard echocardiographic measures. Cox proportional hazards models were used for adjusted survival analyses. Mean patient follow-up was three years.ResultsPatients with LVH were older (68 vs. 65 years, p < 0.01), more often women (54% vs. 36%, p < 0.01), and black (25% vs. 16%, p < 0.01), and had higher unadjusted three-year mortality rates than patients without LVH (42% vs. 34%, p < 0.01). Left ventricular hypertrophy remained an independent predictor of mortality after adjusting for other clinical risk factors (hazard ratio 1.56, 95% confidence interval 1.35 to 1.80) with prognostic importance equivalent to that of left ventricular ejection fraction. Although the relative risk of LVH did not vary by race or gender, the attributable risk of LVH was greater in blacks and women.ConclusionsClinicians should consider the prognostic importance of LVH when assessing risk in patients with CAD. Because LVH is more common among black and women patients with CAD, it partially accounts for racial and gender differences in survival

    ATP-induced reversed thermal sensitivity of O2 binding in both major haemoglobin polymorphs of the non-endothermic Atlantic cod, Gadus morhua.

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    Atlantic cod is a species that is affected by climate change, with some populations being exposed to higher temperatures than others. The two polymorphs of its major haemoglobin type (HbI) show an inverse change in frequency along a latitudinal temperature cline in the North East Atlantic, which has been associated with differences in population performance and behavioural traits. An earlier study at the northern distribution limit of the species reported differential temperature sensitivities of red blood cell oxygen (O2) affinity between the northern cold-water HbI-2 polymorph and its southern, warm-water HbI-1 counter-part, which has since widely been held as adaptive for the species across its distributional range. The present study critically re-examined this hypothesis by comparing the thermal sensitivity of O2 binding in both purified HbI polymorphs from the southern, high-temperature distribution limit of the species under controlled conditions of allosteric modifiers of Hb function. Contrary to the prevailing view, the O2 affinity of the major HbI polymorphs did not differ from each other under any of the tested conditions. Depending on pH and ATP concentration, the temperature-sensitive and temperature-insensitive Hbā€“O2 affinity phenotypes ā€“ previously exclusively ascribed to HbI-1 and HbI-2, respectively ā€“ could be induced in both HbI polymorphs. These results are the first to establish a molecular mechanism behind a reversed temperature dependence of red blood cell O2 affinity in a non-endotherm fish and lay the basis for future studies on alternative mechanisms behind the differences in distribution, performance and behavioural traits associated with the different HbI polymorphs of Atlantic cod

    738ā€“2 The Evolution of Therapy for Single Vessel Disease: A Treatment Comparison of Medicine, Angioplasty and Left Internal Mammary Artery Graft for Proximal Left Anterior Descending Disease

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    Saphenous vein bypass grafting for single vessel disease offers no survival or symptom relief advantage compared to medical therapy. Recent evidence suggests the use of the internal mammary artery or PTCA may be more beneficial than medicine. To examine the outcome of these treatment strategies, a retrospective analysis of prospectively collected data on 23,018 consecutive patients undergoing cardiac catheterization between April 1986 and February 1994 was performed. Of the 6,432 patients with single vessel disease, 1,222 had a proximal left anterior descending (LAD) stenosis&gt;74% and no prior PTCA or CABG. A total of 289 were managed medically, 760 underwent PTCA, and 172 received a left internal mammary artery (LIMA) graft.Baseline demographic data and risk factor profiles were similar except for a higher incidence of diabetes (19 vs 15 vs 11%), history of MI (72 vs 58 vs 48%) CHF (18 vs 7 vs 8%), and total occlusions (44 vs 17 vs 7%) and lower incidence of unstable angina (40 vs 61 vs 64%) in the medical group as compared to PTCA and LIMA graft, respectively.Kaplan-Meier 6-year estimates:EventsMedicinePTCALIMAP-valueā€“unadjusted survival (%)7885910.001ā€“adjusted survival (%)8486900.24ā€“event-free survival (%)5443720.0001ConclusionThere is a trend towards improved long-term survival in proximal LAD disease with a strategy of revascularization, particularly the LIMA graft. Furthermore, event-free survival is significantly improved with the LIMA graft as compared to medical therapy or PTCA

    Haplotype Association Mapping Identifies a Candidate Gene Region in Mice Infected With Staphylococcus aureus

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    Exposure to Staphylococcus aureus has a variety of outcomes, from asymptomatic colonization to fatal infection. Strong evidence suggests that host genetics play an important role in susceptibility, but the specific host genetic factors involved are not known. The availability of genome-wide single nucleotide polymorphism (SNP) data for inbred Mus musculus strains means that haplotype association mapping can be used to identify candidate susceptibility genes. We applied haplotype association mapping to Perlegen SNP data and kidney bacterial counts from Staphylococcus aureus-infected mice from 13 inbred strains and detected an associated block on chromosome 7. Strong experimental evidence supports the result: a separate study demonstrated the presence of a susceptibility locus on chromosome 7 using consomic mice. The associated block contains no genes, but lies within the gene cluster of the 26-member extended kallikrein gene family, whose members have well-recognized roles in the generation of antimicrobial peptides and the regulation of inflammation. Efficient mixed-model association (EMMA) testing of all SNPs with two alleles and located within the gene cluster boundaries finds two significant associations: one of the three polymorphisms defining the associated block and one in the gene closest to the block, Klk1b11. In addition, we find that 7 of the 26 kallikrein genes are differentially expressed between susceptible and resistant mice, including the Klk1b11 gene. These genes represent a promising set of candidate genes influencing susceptibility to Staphylococcus aureus

    Evaluation of the impact of a school gardening intervention on children's fruit and vegetable intake: a randomised controlled trial.

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    Background: Current academic literature suggests that school gardening programmes can provide an interactive environment with the potential to change childrenā€™s fruit and vegetable intake. This is the first cluster randomised controlled trial (RCT) designed to evaluate whether a school gardening programme can have an effect on childrenā€™s fruit and vegetable intake. Methods: The trial included children from 23 schools; these schools were randomised into two groups, one to receive the Royal Horticultural Society (RHS)-led intervention and the other to receive the less involved Teacher-led intervention. A 24-hour food diary (CADET) was used to collect baseline and follow-up dietary intake 18 months apart. Questionnaires were also administered to evaluate the intervention implementation. Results: A total of 641 children completed the trial with a mean age of 8.1 years (95% CI: 8.0, 8.4). The unadjusted results from multilevel regression analysis revealed that for combined daily fruit and vegetable intake the Teacher-led group had a higher daily mean change of 8 g (95% CI: āˆ’19, 36) compared to the RHS-led group -32 g (95% CI: āˆ’60, āˆ’3). However, after adjusting for possible confounders this difference was not significant (intervention effect: āˆ’40 g, 95% CI: āˆ’88, 1; pā€‰=ā€‰0.06). The adjusted analysis of process measures identified that if schools improved their gardening score by 3 levels (a measure of school gardening involvement - the scale has 6 levels from 0 ā€˜no gardenā€™ to 5 ā€˜community involvementā€™), irrespective of group allocation, children had, on average, a daily increase of 81 g of fruit and vegetable intake (95% CI: 0, 163; pā€‰=ā€‰0.05) compared to schools that had no change in gardening score. Conclusions: This study is the first cluster randomised controlled trial designed to evaluate a school gardening intervention. The results have found very little evidence to support the claims that school gardening alone can improve childrenā€™s daily fruit and vegetable intake. However, when a gardening intervention is implemented at a high level within the school it may improve childrenā€™s daily fruit and vegetable intake by a portion. Improving childrenā€™s fruit and vegetable intake remains a challenging task

    Molecular Russian dolls

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    The host-guest recognition between two macrocycles to form hierarchical non-intertwined ring-in-ring assemblies remains an interesting and challenging target in noncovalent synthesis. Herein, we report the design and characterization of a box-in-box assembly on the basis of host-guest radical-pairing interactions between two rigid diradical dicationic cyclophanes. One striking feature of the box-in-box complex is its ability to host various 1,4-disubstituted benzene derivatives inside as a third component in the cavity of the smaller of the two diradical dicationic cyclophanes to produce hierarchical Russian doll like assemblies. These results highlight the utility of matching the dimensions of two different cyclophanes as an efficient approach for developing new hybrid supramolecular assemblies with radical-paired ring-in-ring complexes and smaller neutral guest molecules

    Can agricultural cultivation methods influence the healthfulness of crops for foods

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    The aim of the current study was to investigate if there are any health eļ¬€ects of long-term consumption of organically grown crops using a rat model. Crops were retrieved over two years from along-term ļ¬eld trial at three diļ¬€erent locations in Denmark, using three diļ¬€erent cultivation systems(OA, organic based on livestock manure; OB, organic based on green manure; and C, conventional with mineral fertilizers and pesticides)with two ļ¬eld replicates. The cultivation system had an impact on the nutritional quality, aļ¬€ecting Ī³-tocopherol, some amino acids, and fatty acid composition. Additionally, the nutritional quality was aļ¬€ected by harvest year and location. However, harvest year and location rather than cultivation system aļ¬€ected the measured health biomarkers. In conclusion, the diļ¬€erences in dietary treatments composed of ingredients from diļ¬€erent cultivation systems did not lead to signiļ¬cant diļ¬€erences in the measured health biomarkers, except for a signiļ¬cant diļ¬€erence in plasma IgGl evels
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