186 research outputs found

    Assessing the Impacts of Increasing the Availability of Non-Automobile Modes of Transportation on Carbon Emissions and Accessibility in Worcester

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    Over-reliance on cars in Worcester, Massachusetts represents a significant barrier to the introduction of accessible and ecologically sound modes of transportation. Through increases in frequency, accessibility, and service area, bus transportation in Worcester can offer a viable alternative to personal vehicle usage. In conjunction with the changes to buses, improvements to infrastructure for non-motorist transportation modes such as cycling, walking and assistive equipment will further reduce reliance on personal motor vehicles. Additional policies discouraging the use of motor vehicles is also suggested, with limited traffic zones and vehicle weight restrictions being implemented. With the developments and policy outlined within this paper, Worcester’s reliance on the motor vehicle can be reduced resulting in not only a reduced carbon output, but a rejuvenated and accessible mixed use city

    The Role Of Secondary Vaccine Failure In Measles outbreaks

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    ABSTRAK An outbreak of measles in 1985-1986 in a community where measles vaccine trials had been carried out from 1974-1976 allowed the assessment of the role of secondaryvaccine failures in previously immunized children. A total of 188 children from the vaccine trial were followed. Of these, 175 seroconverted initially while 13 (6 percent) required re-immunization (primary failure). A total of 13 cases of measles, eight of which were laboratory and/or physician-confirmed, were reported in this cohort. Of these, nine cases occurred in the 175 subjects who had hemagglutination inhibition (HI) and neutralizing antibody responses following the initial immunization. These nine cases represent secondary vaccine failures. An additional four cases occured in the 13 subjects with primary vaccine failure. We conclude that secondary vaccine failures occur and that while primary failures account for most cases, secondary vaccine failures contribute to the occurrence of measles cases in an epidemic. A booster dose of measles vaccine may be necessary to reduce susceptibility to a sufficiently low level to allow the goal of measles elimination to be achieved. Key word : vaccin

    Human skeletal muscle nitrate and nitrite in individuals with peripheral arterial disease: effect of inorganic nitrate supplementation and exercise

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    Skeletal muscle may act as a reservoir for N-oxides following inorganic nitrate supplementation. This idea is most intriguing in individuals with peripheral artery disease (PAD) who are unable to endogenously upregulate nitric oxide. This study analyzed plasma and skeletal muscle nitrate and nitrite concentrations along with exercise performance, prior to and following 12-weeks of exercise training combined with oral inorganic nitrate supplementation (EX+BR) or placebo (EX+PL) in participants with PAD. Non-supplemented, at baseline, there were no differences in plasma and muscle nitrate. For nitrite, muscle concentration was higher than plasma (+0.10 nmol.g−1). After 12 -weeks, acute oral nitrate increased both plasma and muscle nitrate (455.04 and 121.14 nmol.g−1, p < 0.01), which were correlated (r = 0.63, p < 0.01), plasma nitrate increase was greater than in muscle (p < 0.01). Nitrite increased in the plasma (1.01 nmol.g−1, p < 0.05) but not in the muscle (0.22 nmol.g−1) (p < 0.05 between compartments). Peak walk time (PWT) increased in both groups (PL + 257.6 s;BR + 315.0 s). Six-minute walk (6 MW) distance increased only in the (EX+BR) group (BR + 75.4 m). We report no substantial gradient of nitrate (or nitrite) from skeletal muscle to plasma, suggesting a lack of reservoir-like function in participants with PAD. Oral nitrate supplementation produced increases in skeletal muscle nitrate, but not skeletal muscle nitrite. The related changes in nitrate concentration between plasma and muscle suggests a potential for inter-compartmental nitrate “communication”. Skeletal muscle did not appear to play a role in within compartment nitrate reduction. Muscle nitrate and nitrite concentrations did not appear to contribute to exercise performance in patients with PAD

    The remnants of galaxy formation from a panoramic survey of the region around M31

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    In hierarchical cosmological models, galaxies grow in mass through the continual accretion of smaller ones. The tidal disruption of these systems is expected to result in loosely bound stars surrounding the galaxy, at distances that reach 10−10010 - 100 times the radius of the central disk. The number, luminosity and morphology of the relics of this process provide significant clues to galaxy formation history, but obtaining a comprehensive survey of these components is difficult because of their intrinsic faintness and vast extent. Here we report a panoramic survey of the Andromeda galaxy (M31). We detect stars and coherent structures that are almost certainly remnants of dwarf galaxies destroyed by the tidal field of M31. An improved census of their surviving counterparts implies that three-quarters of M31's satellites brighter than MV<−6M_V < -6 await discovery. The brightest companion, Triangulum (M33), is surrounded by a stellar structure that provides persuasive evidence for a recent encounter with M31. This panorama of galaxy structure directly confirms the basic tenets of the hierarchical galaxy formation model and reveals the shared history of M31 and M33 in the unceasing build-up of galaxies.Comment: Published in Nature. Supplementary movie available at https://www.astrosci.ca/users/alan/PANDAS/Latest%20news%3A%20movie%20of%20orbit.htm

    Daily Dosing of Rifapentine Cures Tuberculosis in Three Months or Less in the Murine Model

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    Eric Nuermberger and colleagues found that after two months of treatment, mice with lung cultures positive for tuberculosis that received daily doses of rifapentine- and moxifloxacin-containing regimens converted to negative lung cultures. This finding could make possible the development of shorter treatment regimens for humans

    The nucleoid-associated proteins H-NS and FIS modulate the DNA supercoiling response of the pel genes, the major virulence factors in the plant pathogen bacterium Dickeya dadantii

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    Dickeya dadantii is a pathogen infecting a wide range of plant species. Soft rot, the visible symptom, is mainly due to the production of pectate lyases (Pels) that can destroy the plant cell walls. Previously we found that the pel gene expression is modulated by H-NS and FIS, two nucleoid-associated proteins (NAPs) modulating the DNA topology. Here, we show that relaxation of the DNA in growing D. dadantii cells decreases the expression of pel genes. Deletion of fis aggravates, whereas that of hns alleviates the negative impact of DNA relaxation on pel expression. We further show that H-NS and FIS directly bind the pelE promoter and that the response of D. dadantii pel genes to stresses that induce DNA relaxation is modulated, although to different extents, by H-NS and FIS. We infer that FIS acts as a repressor buffering the negative impact of DNA relaxation on pel gene transcription, whereas H-NS fine-tunes the response of virulence genes precluding their expression under suboptimal conditions of supercoiling. This novel dependence of H-NS effect on DNA topology expands our understanding of the role of NAPs in regulating the global bacterial gene expression and bacterial pathogenicity

    Can modeling of HIV treatment processes improve outcomes? Capitalizing on an operations research approach to the global pandemic

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    <p>Abstract</p> <p>Background</p> <p>Mathematical modeling has been applied to a range of policy-level decisions on resource allocation for HIV care and treatment. We describe the application of classic operations research (OR) techniques to address logistical and resource management challenges in HIV treatment scale-up activities in resource-limited countries.</p> <p>Methods</p> <p>We review and categorize several of the major logistical and operational problems encountered over the last decade in the global scale-up of HIV care and antiretroviral treatment for people with AIDS. While there are unique features of HIV care and treatment that pose significant challenges to effective modeling and service improvement, we identify several analogous OR-based solutions that have been developed in the service, industrial, and health sectors.</p> <p>Results</p> <p>HIV treatment scale-up includes many processes that are amenable to mathematical and simulation modeling, including forecasting future demand for services; locating and sizing facilities for maximal efficiency; and determining optimal staffing levels at clinical centers. Optimization of clinical and logistical processes through modeling may improve outcomes, but successful OR-based interventions will require contextualization of response strategies, including appreciation of both existing health care systems and limitations in local health workforces.</p> <p>Conclusion</p> <p>The modeling techniques developed in the engineering field of operations research have wide potential application to the variety of logistical problems encountered in HIV treatment scale-up in resource-limited settings. Increasing the number of cross-disciplinary collaborations between engineering and public health will help speed the appropriate development and application of these tools.</p

    Structure-Based Exploration and Exploitation of the S4 Subsite of Norovirus 3CL Protease in the Design of Potent and Permeable Inhibitors

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    Human noroviruses are the primary cause of epidemic and sporadic acute gastroenteritis. The worldwide high morbidity and mortality associated with norovirus infections, particularly among the elderly, immunocompromised patients and children, constitute a serious public health concern. There are currently no approved human vaccines or norovirus-specific small-molecule therapeutics or prophylactics. Norovirus 3CL protease has recently emerged as a potential therapeutic target for the development of anti-norovirus agents. We hypothesized that the S4 subsite of the enzyme may provide an effective means of designing potent and cell permeable inhibitors of the enzyme. We report herein the structure-guided exploration and exploitation of the S4 subsite of norovirus 3CL protease in the design and synthesis of effective inhibitors of the protease
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