801 research outputs found

    Identification of Escherichia coli from broiler chickens in Jordan, their antimicrobial resistance, gene characterization and the associated risk factors

    Get PDF
    Avian pathogenic Escherichia coli (APEC) is the principle cause of colibacillosis affecting poultry. The main challenge to the poultry industry is antimicrobial resistance and the emergence of multidrug resistant bacteria that threaten the safety of the food chain. Risk factors associated with emergence of antimicrobial resistance among avian pathogenic E. coli were correlated with the inappropriate use of antimicrobials along with inadequate hygienic practices, which encourages the selection pressure of antimicrobial resistant APEC. The aim of this study was to isolate, identify, serogroup and genotype APEC from broilers, assess their antibiotic resistance profile, expressed genes and the associated risk factors

    Second-Order Coherence Across the Brillouin Lasing Threshold

    Full text link
    Brillouin-Mandelstam scattering is one of the most accessible nonlinear optical phenomena and has been widely studied since its theoretical discovery one hundred years ago. The scattering mechanism is a three-wave mixing process between two optical fields and one acoustic field and has found a broad range of applications spanning microscopy to ultra-narrow-linewidth lasers. Building on the success of utilizing this nonlinearity at a classical level, a rich avenue is now being opened to explore Brillouin scattering within the paradigm of quantum optics. Here, we take a key step in this direction by employing quantum optical techniques yet to be utilized for Brillouin scattering to characterize the second-order coherence of Stokes scattering across the Brillouin lasing threshold. We use a silica microsphere resonator and single-photon counters to observe the expected transition from bunched statistics of thermal light below the lasing threshold to Poissonian statistics of coherent light above the threshold. Notably, at powers approaching the lasing threshold, we also observe super-thermal statistics, which arise due to instability and a ``flickering'' in and out of lasing as the pump field is transiently depleted. The statistics observed across the transition, including the ``flickering'', are a result of the full nonlinear three-wave mixing process and cannot be captured by a linearized model. These measurements are in good agreement with numerical solutions of the three-wave Langevin equations and are well demarcated by analytical expressions for the instability and the lasing thresholds. These results demonstrate that applying second-order-coherence and photon-counting measurements to Brillouin scattering provides new methods to advance our understanding of Brillouin scattering itself and progress toward quantum-state preparation and characterization of acoustic modes.Comment: Main (8 pages, 2 figures) + Supplementary (6 pages, 1 figures), Submitte

    Delayed evaluation of combat-related penetrating neck trauma

    Get PDF
    ObjectiveThe approach to penetrating trauma of the head and neck has undergone significant evolution and offers unique challenges during wartime. Military munitions produce complex injury patterns that challenge conventional diagnosis and management. Mass casualties may not allow for routine exploration of all stable cervical blast injuries. The objective of this study was to review the delayed evaluation of combat-related penetrating neck trauma in patients after evacuation to the United States.MethodFrom February 2003 through April 2005, a series of patients with military-associated penetrating cervical trauma were evacuated to a single institution, prospectively entered into a database, and retrospectively reviewed.ResultsSuspected vascular injury from penetrating neck trauma occurred in 63 patients. Injuries were to zone II in 33%, zone III in 33%, and zone I in 11%. The remaining injuries involved multiple zones, including the lower face or posterior neck. Explosive devices wounded 50 patients (79%), 13 (21%) had high-velocity gunshot wounds, and 19 (30%) had associated intracranial or cervical spine injury. Of the 39 patients (62%) who underwent emergent neck exploration in Iraq or Afghanistan, 21 had 24 injuries requiring ligation (18), vein interposition or primary repair (4), polytetrafluoroethylene (PTFE) graft interposition (1), or patch angioplasty (1). Injuries occurred to the carotid, vertebral, or innominate arteries, or the jugular vein. After evacuation to the United States, all patients underwent radiologic evaluation of the head and neck vasculature. Computed tomography angiography was performed in 45 patients (71%), including six zone II injuries without prior exploration. Forty (63%) underwent diagnostic arteriography that detected pseudoaneurysms (5) or occlusions (8) of the carotid and vertebral arteries. No occult venous injuries were noted. Delayed evaluation resulted in the detection of 12 additional occult injuries and one graft thrombosis in 11 patients. Management included observation (5), vein or PTFE graft repair (3), coil embolization (2), or ligation (1).ConclusionsPenetrating multiple fragment injury to the head and neck is common during wartime. Computed tomography angiography is useful in the delayed evaluation of stable patients, but retained fragments produce suboptimal imaging in the zone of injury. Arteriography remains the imaging study of choice to evaluate for cervical vascular trauma, and its use should be liberalized for combat injuries. Stable injuries may not require immediate neck exploration; however, the high prevalence of occult injuries discovered in this review underscores the need for a complete re-evaluation upon return to the United States

    Excitation functions of natZn(p,x) nuclear reactions with proton beam energy below 18 MeV

    Get PDF
    Introduction We measured the excitation functions of natZn (p,x) reactions up to 17.6 MeV using the stacked-foils activation technique. High-purity natural zinc (and copper) foils were irradiated with proton beams from an 18MeV medical cyclotron, the predominant purpose of which is to provide a routine regional service for clinical PET radiopharmaceuticals. Thick-target integral yields were also deduced from the measured excitation functions of the produced radioisotopes. These results were compared with the literature and were found to be in good agreement with most but not all published reports. Material and Methods The excitation functions of the natZn(p,x) reactions were measured by the well-known stacked foil technique (1). High purity zinc foils (99.99%; Goodfellow Metals Ltd., UK) each thickness 0.025 ± 0.003 mm with isotopic composition 64Zn (48.6 %), 66Zn (27.9 %), 67Zn (4.1 %), 68Zn (18.8 %) and 70Zn (0.6 %) were loaded into a solid targetry system on a 300-mm external beam line utilising helium-gas and chilled water to cool the target body (2). A typical foils stack consisted of repeated units of four Zn foils interleaved with a high purity copper foil (0.025 ± 0.004 mm); the latter for monitoring beam flux using the well documented 63,65Cu(p,n)63,65Zn reactions. Foil stacks were irradiated with a primary beam of energy 17.6 MeV, accounting for beam degradation by an obligatory 0.0250 ± 0.0005 mm-thick Havar® foil beam-line vacuum window. Irradiation was for 3 min at a beam current of 5 µA. Activated foils were measured using cryo high-purity Ge γ-spectroscopy to quantify the product radionuclides 61Cu, 66Ga, 67Ga and 65Zn. Radioactivity of each isotope was corrected to end of bombardment (EOB). Results and Conclusion New cross-sectional data for natZn(p,x) reactions up to 17.6 MeV yielding 61Cu, 66Ga, 67Ga and 65Zn isotopes were measured in independent replicated (N = 3) experiments. Results were generally in good agreement with published data. These isotopes can potentially be used in clinical or preclinical studies, following appropriate chemical separations of the zinc, gallium and copper (3). The FIG. 1 shows thick-target integral yields calculated from excitation functions measured in this study. It can be calculated (for example) that useful activities of 61Cu can be produced using a 100 µm thick natZn target in a beam provided by a standard medium-energy medical cyclotron. For example, an irradiation at 40 µA for 2 hr at 17.6 MeV would produce approximately 1.7 GBq of 61Cu at EOB. Such currents are readily achievable using solid targetry in our laboratory (2)

    Attenuation of Counterregulatory Responses to Recurrent Hypoglycemia by Active Thalamic Inhibition: A Mechanism for Hypoglycemia-Associated Autonomic Failure

    Get PDF
    Hypoglycemia, the limiting factor in the glycemic management of diabetes, is the result of the interplay of therapeutic insulin excess and compromised glycemic defenses. The key feature of the latter is an attenuated sympathoadrenal response to hypoglycemia that typically follows an episode of recent antecedent iatrogenic hypoglycemia, a phenomenon termed hypoglycemia-associated autonomic failure (HAAF) in diabetes. We investigated the role of cerebral mechanisms in HAAF by measuring regional brain activation during recurrent hypoglycemia with attenuated counterregulatory responses and comparing it to initial hypoglycemia in healthy individuals

    A self-consistent, multivariate method for the determination of gas-phase rate coefficients, applied to reactions of atmospheric VOCs and the hydroxyl radical

    Get PDF
    Gas-phase rate coefficients are fundamental to understanding atmospheric chemistry, yet experimental data are not available for the oxidation reactions of many of the thousands of volatile organic compounds (VOCs) observed in the troposphere. Here, a new experimental method is reported for the simultaneous study of reactions between multiple different VOCs and OH, the most important daytime atmospheric radical oxidant. This technique is based upon established relative rate concepts but has the advantage of a much higher throughput of target VOCs. By evaluating multiple VOCs in each experiment, and through measurement of the depletion in each VOC after reaction with OH, the OH + VOC reaction rate coefficients can be derived. Results from experiments conducted under controlled laboratory conditions were in good agreement with the available literature for the reaction of 19 VOCs, prepared in synthetic gas mixtures, with OH. This approach was used to determine a rate coefficient for the reaction of OH with 2,3-dimethylpent-1-ene for the first time; k =  5.7 (±0.3)  ×  10⁻¹¹ cm³ molecule⁻¹ s⁻¹. In addition, a further seven VOCs had only two, or fewer, individual OH rate coefficient measurements available in the literature. The results from this work were in good agreement with those measurements. A similar dataset, at an elevated temperature of 323 (±10) K, was used to determine new OH rate coefficients for 12 aromatic, 5 alkane, 5 alkene and 3 monoterpene VOC + OH reactions. In OH relative reactivity experiments that used ambient air at the University of York, a large number of different VOCs were observed, of which 23 were positively identified. Due to difficulties with detection limits and fully resolving peaks, only 19 OH rate coefficients were derived from these ambient air samples, including 10 reactions for which data were previously unavailable at the elevated reaction temperature of T =  323 (±10) K

    The UK Burden of Injury Study – a protocol. [National Research Register number: M0044160889]

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Globally and nationally large numbers of people are injured each year, yet there is little information on the impact of these injuries on people's lives, on society and on health and social care services. Measurement of the burden of injuries is needed at a global, national and regional level to be able to inform injured people of the likely duration of impairment; to guide policy makers in investing in preventative measures; to facilitate the evaluation and cost effectiveness of interventions and to contribute to international efforts to more accurately assess the global burden of injuries.</p> <p>Methods/Design</p> <p>A prospective, longitudinal multi-centre study of 1333 injured individuals, atttending Emergency Departments or admitted to hospital in four UK areas: Swansea, Surrey, Bristol and Nottingham. Specified quotas of patients with defined injuries covering the whole spectrum will be recruited. Participants (or a proxy) will complete a baseline questionnaire regarding their injury and pre-injury quality of life. Follow up occurs at 1, 4, and 12 months post injury or until return to normal function within 12 months, with measures of health service utilisation, impairment, disability, and health related quality of life. National estimates of the burden of injuries will be calculated by extrapolation from the sample population to national and regional computerised hospital in-patient, emergency department and mortality data.</p> <p>Discussion</p> <p>This study will provide more detailed data on the national burden of injuries than has previously been available in any country and will contribute to international collaborative efforts to more accurately assess the global burden of injuries. The results will be used to advise policy makers on prioritisation of preventive measures, support the evaluation of interventions, and provide guidance on the likely impact and degree of impairment and disability following specific injuries.</p

    Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

    Get PDF
    One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions
    corecore