2,290 research outputs found

    Susceptibility in vitro of canine methicillin-resistant and -susceptible staphylococcal isolates to fusidic acid, chlorhexidine and miconazole: opportunities for topical therapy of canine superficial pyoderma

    Get PDF
    OBJECTIVES: Increasing multidrug resistance amongst canine pathogenic staphylococci has renewed interest in topical antibacterial therapy for skin infections in the context of responsible veterinary prescribing. We therefore determined the activity in vitro of three clinically relevant topical agents and synergism between two of them against Staphylococcus pseudintermedius and Staphylococcus aureus. METHODS: The MICs of fusidic acid (n = 199), chlorhexidine (n = 198), miconazole (n = 198) and a 1:1 combination of miconazole/chlorhexidine (n = 198) were determined for canine isolates [50 MRSA and 49 methicillin-resistant S. pseudintermedius (MRSP), 50 MSSA and 50 methicillin-susceptible S. pseudintermedius (MSSP)] collected from the UK and Germany using an agar dilution method (CLSI VET01-A4). Fractional inhibitory concentration (FIC) indices were calculated to assess the interaction of miconazole with chlorhexidine. RESULTS: MICs of each drug/combination were significantly (P < 0.0005) higher for S. aureus when compared with S. pseudintermedius. Most strains (n = 172) had an MIC of fusidic acid of ≤0.03 mg/L (MIC ≥64 mg/L, n = 5 MRSA). All strains had MICs of chlorhexidine of 0.5–4 mg/L, except for one MRSA (MIC = 8 mg/L). All but four strains had MICs of miconazole of 1–4 mg/L (MIC = 16 mg/L, n = 3; MIC = 256 mg/L, n = 1). Miconazole/chlorhexidine (1:1 ratio) had a synergistic effect against 49/50 MRSA, 31/50 MSSA, 12/49 MRSP and 23/49 MSSP. CONCLUSIONS: Since the majority of these staphylococci, including methicillin-resistant isolates, had MICs that should be readily exceeded by topical skin application of these agents, their therapeutic efficacy for canine superficial pyoderma should be assessed. The synergistic interaction shown in vitro supports further clinical evaluation of miconazole/chlorhexidine combination therapy for staphylococcal infection

    Using Simulated Micrometeoroid Impacts to Understand the Progressive Space Weathering of the Surface of Mercury

    Get PDF
    The surfaces of airless bodies such as Mercury are continually modified by space weathering, which is driven by micrometeoroid impacts and solar wind irradiation. Space weathering alters the chemical composition, microstructure, and spectral properties of surface regolith. In lunar and ordinarychondritic style space weathering, these processes affect the reflectance properties by darkening (lowering of reflectance), reddening (increasing reflectance with increasing wavelength), and attenuation of characteristic absorption features. These optical changes are driven by the production of nanophase Febearing particles (npFe). While our understanding of these alteration processes has largely been based on data from the Moon and near-Earth S-type asteroids, the space weathering environment at Mercury is much more extreme. The surface of Mercury experiences a more intense solar wind flux and higher velocity micrometeoroid impacts than its planetary counterparts at 1 AU. Additionally, the composition of Mercurys surface varies significantly from that of the Moon. Most notably, a very low albedo unit has been identified on Mercurys surface, known as the low reflectance material (LRM). This unit is enriched with up to 4 wt.% carbon, likely in the form of graphite, over the local mean. In addition, the surface concentration of Fe across Mercurys surface is low (<2 wt.%) compared to the Moon. Our understanding of how these low-Fe and carbon phases are altered as a result of space weathering processes is limited. Since Fe plays a critical role in the development of space weathering features on other airless surfaces (e.g., npFe), its limited availability on Mercury may strongly affect the space weathering features in surface materials. In order to understand how space weathering affects the chemical, microstructural, and optical properties of the surface of Mercury, we can simulate these processes in the laboratory [7]. Here we used pulsed laser irradiation to simulate the short duration, high temperature events associated with micrometeoroid impacts. We used forsteritic olivine, likely present on the Mercurian surface, with varying FeO contents, each mixed with graphite, in our experiments. We then performed reflectance spectroscopy and electron microscopy to investigate the spectral, chemical, and microstructural changes in these samples

    Scalable high-resolution forecasting of sparse spatiotemporal events with kernel methods: a winning solution to the NIJ "Real-Time Crime Forecasting Challenge"

    Get PDF
    We propose a generic spatiotemporal event forecasting method, which we developed for the National Institute of Justice’s (NIJ) RealTime Crime Forecasting Challenge (National Institute of Justice, 2017). Our method is a spatiotemporal forecasting model combining scalable randomized Reproducing Kernel Hilbert Space (RKHS) methods for approximating Gaussian processes with autoregressive smoothing kernels in a regularized supervised learning framework. While the smoothing kernels capture the two main approaches in current use in the field of crime forecasting, kernel density estimation (KDE) and self-exciting point process (SEPP) models, the RKHS component of the model can be understood as an approximation to the popular log-Gaussian Cox Process model. For inference, we discretize the spatiotemporal point pattern and learn a log-intensity function using the Poisson likelihood and highly efficient gradientbased optimization methods. Model hyperparameters including quality of RKHS approximation, spatial and temporal kernel lengthscales, number of autoregressive lags, bandwidths for smoothing kernels, as well as cell shape, size, and rotation, were learned using crossvalidation. Resulting predictions significantly exceeded baseline KDE estimates and SEPP models for sparse events

    Mammals of Spanish Peaks State Wildlife Area, Colorado

    Get PDF
    Habitats and relative abundance of small mammals in the Spanish Peaks State Wildlife Area in western Las Animas Co., Colorado, were assessed. A total of 821 mammals of 20 species was collected in 2750 trapnights between 31 May and 19 August of 1981. Eight additional species of mammals were observed on the wildlife area but not documented. The deer mouse (Peromyscus maniculatus) and rock mouse (P. difficilis) were the most abundant small mammals, accounting for 63 and 16%, respectively, of the total catch. The deer mouse was the only species caught in every habitat sampled. Abert\u27s squirrel (Sciurus abert,) previously has not been recorded in Colorado from as far southeast as the Spanish Peaks State Wildlife Area. The mammalian fauna of Colorado has been the subject of numerous studies since the late 1800s. Early studies were by Cockerell (1890), Warren (1906), Cary (1911), and Warren (1942, published posthumously). More recent investigations include the book by Lechleitner (1969), the exhaustive compilation by Armstrong (1972), and the latilong surveys by Bissell (1978, 1982). In spite of these studies, several regions of Colorado remain poorly represented in collections. Armstrong (1972) noted that certain poorly surveyed parts of the western two-thirds of the state appear to me to be ... significant from the standpoint of zoogeography. Western Las Animas County--the Park Plateau and Culebra Range [of the Sangre de Cristo Mountains]--is such an area. In a later publication, Armstrong et al. (1973) noted that additional field investigations were needed in the vicinity of the Wet Mountains, a biogeographically important region where several species of grassland mammals reach altitudinal extremes and certain southern species reach northern limits. With this in mind, the Colorado Division of Wildlife initiated fieldwork in the Spanish Peaks State Wildlife Area to sample the vertebrate fauna in general and to assess habitat associations and relative abundance of small mammals in particular. This report documents the mammals collected and observed in the Spanish Peaks State Wildlife Area during summer of 1981 and summarizes biological data on mammals obtained at that time.https://scholars.fhsu.edu/fort_hays_studies_series/1067/thumbnail.jp

    High temperature stable separator for lithium batteries based on SiO² and hydroxypropyl guar gum

    Get PDF
    A novel membrane based on silicon dioxide (SiO2_{2}) and hydroxypropyl guar gum (HPG) as binder is presented and tested as a separator for lithium-ion batteries. The separator is made with renewable and low cost materials and an environmentally friendly manufacturing processing using only water as solvent. The separator offers superior wettability and high electrolyte uptake due to the optimized porosity and the good affinity of SiO2_{2} and guar gum microstructure towards organic liquid electrolytes. Additionally, the separator shows high thermal stability and no dimensional-shrinkage at high temperatures due to the use of the ceramic filler and the thermally stable natural polymer. The electrochemical tests show the good electrochemical stability of the separator in a wide range of potential, as well as its outstanding cycle performance
    • …
    corecore