539 research outputs found

    Body temperature and body mass of hibernating little brown bats Myotis lucifugus in hibernacula affected by white-nose syndrome

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    Populations of hibernating bats in the northeastern USA are being decimated by white-nose syndrome (WNS). Although the ultimate cause of death is unknown, one possibility is the premature depletion of fat reserves. The immune system is suppressed during hibernation. Although an elevated body temperature (Tb) may facilitate an immune response, it also accelerates the depletion of fat stores. We sought to determine if little brown bats Myotis lucifugus Le Conte 1831 hibernating in WNS-affected hibernacula have an elevated Tb and reduced fat stores, relative to WNSunaffected Indiana bats Myotis sodalis Miller and Allen 1928 from Indiana. We found that WNS-affected M. lucifugus maintain a slightly, but significantly, higher skin temperature (Tskin), relative to surrounding rock temperature, than do M. sodalis from Indiana. We also report that WNS-affected M. lucifugus weigh significantly less than M. lucifugus from a hibernaculum outside of the WNS region. However, the difference in Tskin is minimal and we argue that the elevated Tb is unlikely to explain the emaciation documented in WNS-affected bats.The Indiana State University Center for North American Bat Research and Conservationhttp://acta.zbs.bialowieza.pl/ab201

    Following Guidelines for Drug-Resistant Tuberculosis: “Yes, it’s a challenge”

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    BACKGROUND: Drug-resistant tuberculosis (DR-TB) is a major contributor to antimicrobial resistance (AMR) globally and is projected to be responsible for up to a quarter of AMR-associated deaths in the future. Management of DR-TB is increasingly decentralised to primary healthcare settings, and simultaneously becoming more complex due to a growing range of treatment options (e.g. novel agents, shorter regimens). This is reflected in the numerous recent updates to international guidelines and as such understanding the barriers and enablers to how healthcare workers access and use guidelines is vital. MATERIAL AND METHODS: We used an established psychological framework – the theoretical domains framework (TDF) – to construct and analyse an online survey and focus groups to explore healthcare workers current use of DR-TB guidelines in South Africa. We aimed to identify barriers and enablers with which to direct future attempts at improving guideline use. RESULTS: There were 19 responses to the online survey and 14 participants in two focus groups. 28% used the most up-to-date national guidelines, 79% accessed guidelines primarily on electronic devices. The TDF domains of ‘Social Influences’ (mean Likert score = 4.3) and ‘Beliefs about Consequences’ (4.2) were key enablers, with healthcare workers encouraged to use guidelines and also recognising the value in doing so. ‘Environmental Resources’ (3.7) and ‘Knowledge’ (3.3) were key barriers with limited, or variable access to guidelines and lack of confidence using them being notable issues. This was most noted for certain subgroups: children, HIV co-infected, pregnant women (2.7). DISCUSSION: Current use of DR-TB guidelines in South Africa is suboptimal. Planned interventions should focus on overcoming the identified key barriers and might include an increased use of digital tools

    Frequency distribution of post race urine pH from Standardbreds compared with Thoroughbreds: research and regulatory significance

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    The concentration of drugs and drug metabolites in urine samples of racing horses is strongly influenced by urine pH(Tobin, 1981), depending on whether the drugs are weak acids or weak bases. Drugs that are weak acids tend to concentrate in besic urine. In contrast, drugs that are weak bases tend to concentrate in acidic urine. These relationships have a well-established theoretical basis (the Henderson-Hasselbalch relationship) and have been demonstrated repeatedly in experimental animals and man (Tobin, 1981). More recently, evidence suggests that these relationships also occur with clinically and forensically significant agents in equine urine (Wood, et al. 1990; Gerken et al.1991.

    The estimated burden of fungal disease in South Africa

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    Background. With a population of 56.5 million, over 7 million persons living with HIV, one of the world’s highest rates of tuberculosis (TB) and a large proportion of the population living in poverty, South Africa (SA)’s fungal disease burden is probably substantial and broad in scope.Objectives. To estimate the burden of fungal disease in SA.Methods. Using total and at-risk populations and national, regional and occasionally global data, we estimated the incidence and prevalence of the majority of fungal diseases in SA.Results. Estimates for the annual incidence of HIV-related life-threatening fungal disease include cryptococcal meningitis (8 357 cases), Pneumocystis pneumonia (4 452 cases) and endemic mycoses (emergomycosis, histoplasmosis and blastomycosis, with 100, 60 and 10 cases per year, respectively). We estimate 3 885 cases of invasive aspergillosis annually. The annual burden of candidaemia and Candida peritonitis is estimated at 5 421 and 1 901 cases, respectively. The epidemic of pulmonary TB has probably driven up the prevalence of chronic pulmonary aspergillosis to 99 351 (175.8/100 000), perhaps the highest in the world. Fungal asthma probably affects >100 000 adults. Mucosal candidiasis is common, with an annual prevalence estimated at 828 666 and 135 289 oral and oesophageal cases, respectively, complicating HIV infection alone (estimates in other conditions not made), and over a million women are estimated to be affected by recurrent vulvovaginal candidiasis each year. Tinea capitis in children is common and conservatively estimated at >1 000 000 cases. The inoculation mycoses sporotrichosis, chromoblastomycosis and eumycetoma occur occasionally (with 40, 40 and 10 cases estimated, respectively). Overall, we estimate that over 3.2 million South Africans are afflicted by a fungal disease each year (7.1% of the population).Conclusions. Significant numbers of South Africans are estimated to be affected each year by fungal infections, driven primarily by the syndemics of HIV, TB and poverty. These estimates emphasise the need for better epidemiological data, and for improving the diagnosis and management of these diseases

    A GC-MS Method for the Determination of Isoxsuprine in Biological Fluids of the Horse Utilizing Electron Impact Ionization

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    Isoxsuprine is used to treat navicular disease and other lower-limb problems in the horse. Isoxsuprine is regulated as a class 4 compound by the Association of Racing Commissioners, International (ARCI) and, thus, requires regulatory monitoring. A gas chromatography-mass spectrometry method utilizing electron impact ionization was developed and validated for the quantitation of isoxsuprine in equine plasma or equine urine. The method utilized robotic solid-phase extraction and tri-methyl silyl ether products of derivatization. Products were bis-trimethylsilyl (TMS) isoxsuprine and tris-TMS ritodrine, which released intense quantifier ions m/z 178 for isoxsuprine and m/z 236 for ritodrine that were products of C-C cleavage. To our knowledge, this procedure is faster and more sensitive than other methods in the literature. Concentrations in urine and plasma of isoxsuprine were determined from a calibrator curve that was generated along with unknowns. Ritodrine was used as an internal standard and was, therefore, present in all samples, standards, and blanks. Validation data was also collected. The limit of detection of isoxsuprine in plasma was determined to be 2 ng/mL, the limit of quantitation of isoxsuprine in plasma was determined to be \u3c 5 ng/mL. The mean coefficient of determination for the calibrator curves for plasma was 0.9925 ± 0.0052 and for calibrator curves for urine 0.9904 ± 0.0075. The recovery efficiencies at concentrations of 50, 200, and 300 ng/mL were 76%, 73%, and 76%, respectively, in plasma and 92%, 89% and 91% in urine

    A method to assess the relevance of nanomaterial dissolution during reactivity testing

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    The reactivity of particle surfaces can be used as a criterion to group nanoforms (NFs) based on similar potential hazard. Since NFs may partially or completely dissolve over the duration of the assays, with the ions themselves inducing a response, reactivity assays commonly measure the additive reactivity of the particles and ions combined. Here, we determine the concentration of ions released over the course of particle testing, and determine the relative contributions of the released ions to the total reactivity measured. We differentiate three classes of reactivity, defined as being A) dominated by particles, B) additive of particles and ions, or C) dominated by ions. We provide examples for each class by analyzing the NF reactivity of Fe2O3, ZnO, CuO, Ag using the ferric reduction ability of serum (FRAS) assay. Furthermore, another two reactivity tests were performed: Dichlorodihydrofluorescin diacetate (DCFH2‑DA) assay and electron paramagnetic resonance (EPR) spectroscopy. We compare assays and demonstrate that the dose‑response may be almost entirely assigned to ions in one assay (CuO in DCFH2‑DA), but to particles in others (CuO in EPR and FRAS). When considering this data, we conclude that one cannot specify the contribution of ions to NF toxicity for a certain NF, but only for a certain NF in a specific assay, medium and dose. The extent of dissolution depends on the buffer used, particle concentration applied, and duration of exposure. This culminates in the DCFH2‑DA, EPR, FRAS assays being performed under different ion‑to‑particle ratios, and differing in their sensitivity towards reactions induced by either ions or particles. If applied for grouping, read‑across, or other concepts based on the similarity of partially soluble NFs, results on reactivity should only be compared if measured by the same assay, incubation time, and dose range

    The Green Bank Northern Celestial Cap Pulsar Survey - I: Survey Description, Data Analysis, and Initial Results

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    We describe an ongoing search for pulsars and dispersed pulses of radio emission, such as those from rotating radio transients (RRATs) and fast radio bursts (FRBs), at 350 MHz using the Green Bank Telescope. With the Green Bank Ultimate Pulsar Processing Instrument, we record 100 MHz of bandwidth divided into 4,096 channels every 81.92 μs\mu s. This survey will cover the entire sky visible to the Green Bank Telescope (δ>40\delta > -40^\circ, or 82% of the sky) and outside of the Galactic Plane will be sensitive enough to detect slow pulsars and low dispersion measure (<<30 pccm3\mathrm{pc\,cm^{-3}}) millisecond pulsars (MSPs) with a 0.08 duty cycle down to 1.1 mJy. For pulsars with a spectral index of -1.6, we will be 2.5 times more sensitive than previous and ongoing surveys over much of our survey region. Here we describe the survey, the data analysis pipeline, initial discovery parameters for 62 pulsars, and timing solutions for 5 new pulsars. PSR J0214++5222 is an MSP in a long-period (512 days) orbit and has an optical counterpart identified in archival data. PSR J0636++5129 is an MSP in a very short-period (96 minutes) orbit with a very low mass companion (8 MJM_\mathrm{J}). PSR J0645++5158 is an isolated MSP with a timing residual RMS of 500 ns and has been added to pulsar timing array experiments. PSR J1434++7257 is an isolated, intermediate-period pulsar that has been partially recycled. PSR J1816++4510 is an eclipsing MSP in a short-period orbit (8.7 hours) and may have recently completed its spin-up phase.Comment: 18 pages, 10 figures, 5 tables, accepted by Ap

    Development of a method for the detection and confirmation of the alpha-2 agonist amitraz and its major metabolite in horse urine

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    Amitraz (N′-(2,4-dimethylphenyl)-N-[[(2,4-dimethylphenyl)imino] methyl]-N-methyl-methanimidamide) is an alpha-2 adrenergic agonist used in veterinary medicine primarily as a scabicide- or acaricide-type insecticide. As an alpha-2 adrenergic agonist, it also has sedative/tranquilizing properties and is, therefore, listed as an Association of Racing Commissioners International Class 3 Foreign Substance, indicating its potential to influence the outcome of horse races. We identified the principal equine metabolite of amitraz as N-2,4-dimethylphenyl-N′-methylformamidine by electrospray ionization(+)-mass spectrometry and developed a gas chromatographic-mass spectrometric (GC-MS) method for its detection, quantitation, and confirmation in performance horse regulation. The GC-MS method involves derivatization with t-butyldimethylsilyl groups; selected ion monitoring (SIM) of m/z 205 (quantifier ion), 278, 261, and 219 (qualifier ions); and elaboration of a calibration curve based on ion area ratios involving simultaneous SIM acquisition of an internal standard m/z 208 quantifier ion based on an in-house synthesized d6 deuterated metabolite. The limit of detection of the method is approximately 5 ng/mL in urine and is sufficiently sensitive to detect the peak urinary metabolite at 1 h post dose, following administration of amitraz at a 75-mg/horse intraveneous dose

    Quantum polarization tomography of bright squeezed light

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    We reconstruct the polarization sector of a bright polarization squeezed beam starting from a complete set of Stokes measurements. Given the symmetry that underlies the polarization structure of quantum fields, we use the unique SU(2) Wigner distribution to represent states. In the limit of localized and bright states, the Wigner function can be approximated by an inverse three-dimensional Radon transform. We compare this direct reconstruction with the results of a maximum likelihood estimation, finding an excellent agreement.Comment: 15 pages, 5 figures. Contribution to New Journal of Physics, Focus Issue on Quantum Tomography. Comments welcom
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