58 research outputs found

    Longitudinal study of the immune response and memory following natural bovine respiratory syncytial virus infections in cattle of different age

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    Human and bovine respiratory syncytial virus (HRSV and BRSV) are closely genetically related and cause respiratory disease in their respective host. Whereas HRSV vaccines are still under development, a multitude of BRSV vaccines are used to reduce clinical signs. To enable the design of vaccination protocols to entirely stop virus circulation, we aimed to investigate the duration, character and efficacy of the immune responses induced by natural infections. The systemic humoral immunity was monitored every two months during two years in 33 dairy cattle in different age cohorts following a natural BRSV outbreak, and again in selected individuals before and after a second outbreak, four years later. Local humoral and systemic cellular responses were also monitored, although less extensively. Based on clinical observations and economic losses linked to decreased milk production, the outbreaks were classified as moderate. Following the first outbreak, most but not all animals developed neutralising antibody responses, BRSV-specific IgG1, IgG2 and HRSV F- and HRSV N-reactive responses that lasted at least two years, and in some cases at least four years. In contrast, no systemic T cell responses were detected and only weak IgA responses were detected in some animals. Seronegative sentinels remained negative, inferring that no new infections occurred between the outbreaks. During the second outbreak, reinfections with clinical signs and virus shedding occurred, but the signs were milder, and the virus shedding was significantly lower than in naĂŻve animals. Whereas the primary infection induced similar antibody titres against the prefusion and the post fusion form of the BRSV F protein, memory responses were significantly stronger against prefusion F. In conclusion, even if natural infections induce a long-lasting immunity, it would probably be necessary to boost memory responses between outbreaks, to stop the circulation of the virus and limit the potential role of previously infected adult cattle in the chain of BRSV transmission

    Can precursors improve the transmission of energy at optical frequencies?

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    The recent interest in precursors has been fuelled by the possibility of using them for the efficient transmission of information through absorbing media at radio or optical frequencies. Here we demonstrate that the low attenuation experienced by the Brillouin precursor is attributed to the inherently low absorption of dispersive media near DC, a characteristic already exploited with communications systems using the extremely low frequency (ELF) band. Pulses, regardless of their temporal width and carrier frequency, always obey Beer's law as long as they propagate in the linear time invariant regime. We conclude with an FDTD simulation of the Maxwell–Bloch equations that shows how optical coherent bleaching effects, which take place in the linear time variant regime of the Lorentz oscillator model, can cause sustained deviations from Beer's law over relatively long distances of water

    Multilevel Maxwell-Bloch simulations in inhomogeneously broadened media

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    A compact numerical method for simulating ultrafast pulse interaction with inhomogeneously broadened multi-level media is reported. We use a low-dispersion pseudospectral scheme with fourth order time stepping for Maxwell’s equations, and a weakly coupled operator splitting method for the Bloch equations where inhomogeneous broadening and relaxations are also taken into account. The underlying physics is briefly discussed with emphasis on the formalism used

    Fully Distributed Ubiquitous Information Sharing on a Global Scale for the Internet-of-Things

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    The Internet-of-Things will require ubiquitous informationsharing between connected things on a global scale, whichexisting systems do not offer. Most current efforts focus on solutionsfor information dissemination, which induce single pointsof failure and introduce unnecessary communication delays. Tothis end we propose the SensibleThings platform, which is afully distributed open source architecture for Internet-of-Thingsbased applications. This article describes the major problems thatInternet-of-Things platforms must address, our technical solutionto these problems, and an evaluation thereof. We also present thecurrent progress and a series of demonstrators, which show thewide range of applications enabled by the platform. Finally, wepresent how the platform will be used in our future research andpotential spin off companies

    Annoyance and performance during the experimental chemical challenge of subjects with multiple chemical sensitivity.

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    OBJECTIVES: This study explored the subjective reactions and psychological test performance of smell-intolerant subjects during consecutive challenges to chemicals with contrasting neurotoxic properties. METHODS: Women with symptoms compatible with multiple chemical sensitivity (N=10) and healthy referents (N=20) were individually challenged in an exposure chamber. All the subjects attended two separate 2-hour sessions of exposure to n-butyl acetate and toluene, in counterbalanced sequence. After an initial phase without exposure, air concentrations were increased in steps ranging from 3.6 to 57 mg/m3 for n-butyl acetate and from 11 to 180 mg/m3 for toluene. The response measures comprised ratings of annoyance and smell intensity and also neurobehavioral test performance. RESULTS: Both groups showed an increase in annoyance ratings and a decrease in test performance in the initial unexposed chamber phase and also in the first phase of the chemical exposure, these results indicating slight immediate expectancy or "suggestion" effects. During the six chamber phases, the ratings of mucous membrane irritation and fatigue showed a steeper increase in the group with multiple chemical sensitivity than among the referents, while the ratings of smell intensity and smell annoyance were similar in the two groups. A reduction in test performance was observed during the chamber phases, particularly in the group with multiple chemical sensitivity. No relation was found between the ratings or performance and chemical substance. CONCLUSIONS: Stronger immediate expectancy or "suggestion" reactions than normal did not characterize the group with multiple chemical sensitivity. This group showed a stronger than normal gradual build-up of fatigue, mucous membrane irritation, and reduced performance during chemical exposure. The results offer the most support to an irritative basis for multiple chemical sensitivity

    A comparison of neuropsychological tests for the assessment of chronic toxic encephalopathy

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    BACKGROUND: From the viewpoint of the clinical neuropsychologist, it is not evident if the detection of solvent induced toxic encephalopathy (TE) could be optimized by a modification of the traditional test batteries, adding tests covering new dimensions or monitoring further functional domains. METHODS: To clarify this issue, TE patients were re-examined with (a) the tests traditionally used in screening for TE and (b) some tests hitherto less utilized within neurotoxicology, involving complex attention and frontal lobe functioning. RESULTS: The results do not indicate that tests of the latter category would be more sensitive to TE than the tests traditionally used. Using an optimized core battery, compiled of tests from both categories, the sensitivity and specificity levels reached a maximum of around 0.7 when using as criterion the reproduction of a subnormal test profile (TE type 2B). CONCLUSIONS: A combination of several traditional and a few newer tests is suggested to optimize the detection of TE. Repeated assessments over time are also recommended

    Cardiovascular Risk, Cardiac Function, Physical Activity, and Quality of Life with and without Long-Term Growth Hormone Therapy in Adult Survivors of Childhood Acute Lymphoblastic Leukemia.

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    Context: Long-term data are missing in GH-treated acute lymphoblastic leukemia (ALL) patients. GH therapy may result in poorer outcome regarding cardiovascular (CV) and particularly cardiac effects than in patients with hypothalamic-pituitary disease. Objective: Our objective was to evaluate GH therapy on CV risk, cardiac function, physical activity, and quality of life in ALL patients treated with cranial radiotherapy (18-24 Gy) and chemotherapy (anthracycline dose 120 mg/m(2)). Design and Setting: We conducted a 5- and 8-yr open nonrandomized prospective study in a university hospital clinic. Study Participants: Two groups of GH-deficient ALL patients (aged 25 yr; range 19-32 yr) and matched population controls participated. Interventions: One ALL group (n = 16) received GH for 5 yr, and the other ALL group (n = 13) did not receive GH therapy. Main Outcome Measures: We evaluated the prevalence of CV risk factors and metabolic syndrome (International Diabetes Federation consensus), cardiac function (echocardiography), and quality of life and physical activity questionnaires. Results: In comparison with 8 yr without, 5 yr with GH therapy resulted in significant positive changes in plasma glucose (-0.5 vs. 0.6 mmol/liter, P = 0.002), apolipoprotein B/apolipoprotein A1 ratio (-0.1 vs. 0.0, P = 0.03), and high-density lipoprotein-cholesterol (0.20 vs.-0.01 mmol/liter, P = 0.008) and a significant reduction in the prevalence of metabolic syndrome (P = 0.008). No significant difference in the left-ventricular systolic function or in physical activity and quality of life was recorded before and after 5 or 8 yr, respectively (all P > 0.3). Conclusion: GH therapy reduced the CV risk in this young ALL population but resulted in no clear benefit or deterioration in cardiac function

    Quality-of-life and Surgical Outcome 1 Year After Open and Laparoscopic Incisional Hernia Repair: PROLOVE: A Randomized Controlled Trial.

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    Patients suffering from an incisional hernia after abdominal surgery have an impaired quality of life (QoL). Surgery aims to improve QoL with a minimum risk of further complications. The aim was to analyze QoL, predictors for outcome, including recurrence and reoperation rates during the first postoperative year
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