700 research outputs found

    Hard sphere colloidal dispersions: Mechanical relaxation pertaining to thermodynamic forces

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    The complex viscosity of sterically stabilized (hard) silica spheres in cyclohexane has been measured between 80 Hz and 170 kHz with torsion pendulums and a nickel tube resonator. The observed relaxation behaviour can be attributed to the interplay of hydrodynamic and thermodynamic forces. The validity of the Cox-Merz rule is checked

    Evaluation of the epidemiological importance of classical swine fever infected, E2 sub-unit marker vaccinated animals with RT-nPCR positive blood samples

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    &lt;p&gt;It has been demonstrated that pigs that have been double vaccinated with an E2 sub-unit marker vaccine and that are infected with classical swine fever virus (CSFV) through a natural contact infection may react positive in a CSFV detecting RT-nPCR test, whereas no virus could be isolated by using the conventional virus isolation (VI) technique. To evaluate whether these vaccinated and infected pigs may spread the virus, three experiments were set up. In the first, susceptible pigs were inoculated with serum originating from vaccinated RT-nPCR positive pigs. In the second, vaccinated RT-nPCR positive pigs were brought into contact with sentinel animals. In the third, vertical transmission was evaluated in RT-nPCR positive vaccinated pregnant gilts. In the first two experiments, no proof of virus transmission was found, whereas in the third vertical transmission was observed. The conclusion is that in vaccinated pigs that are positive in RT-nPCR but negative in VI, the level of circulating virus is probably not high enough for horizontal transmission, whereas vertical transmission of the virus is possible.&lt;/p&gt;</p

    Adhesive Hard-Sphere Colloidal Dispersions. A Small-Angle Neutron-Scattering Study of Stickiness and the Structure Factor

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    Small-angle neutron-scattering structure factor measurements were made on sterically stabilized silica spheres dispersed in benzene up to volume fractions of 0.30. Benzene is only a marginal solvent for the stabilizing layer on the surface of the particles. The particles are made attractive by lowering temperature. This attraction is modeled by a square well potential, the depth of which varies with temperature. At the highest temperature studied, our experimental system behaved effectively as an assembly of hard spheres, whereas at the lowest temperature the system approaches a spinodal. Using Baxter's theory we were able to evaluate the interaction parameters and to calculate the structure factor. Experimental structure factors were satisfactorily reproduced over the entire temperature range studied

    Quantification of the spread of Salmonella and the effect of 2 feed additives

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    The aim of this experiment was to quantify the spread of Salmonella Typhimurium in weaned piglets by calculating R0 values. In addition, the effect of 2 feed additives, AROMABIOTIC“ and Shiitake mushroom, on the spread of Salmonella Typhimurium was evaluated. Fifty-nine piglets were allocated to 4 groups: AROMABIOTIC“ (A, n=16), Shiitake mushroom (B, n=16), positive (C, n=16) and negative controls (D, n=11). Half of the piglets of group A, B and C were experimentally inoculated with Salmonella Typhimurium, other piglets were used as susceptibles. Based on Salmonella isolation in faecal swabs, R0 values (95% C.I.) were 4.26 (1.40-34.69), 1.83 (0.86-9.38) and 4.29 (1.09-13.71) for group A, B and C, respectively. None of the measured parameters did indicate significant differences between the groups. Mortality rate was high in all 4 groups, what makes it necessary to repeat the experiment

    Using the behavior change wheel to identify and understand key facilitators and barriers for lifestyle care for postmenopausal breast cancer survivors:A delphi-study

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    BackgroundOptimal approaches to promote sustained adherence to lifestyle and bodyweight recommendations in postmenopausal breast cancer (PMBC) survivors are lacking.PurposeThis Delphi-study aims to identify and understand expert-opinion on potential barriers and facilitators for promoting adherence to these lifestyle and bodyweight recommendations in (clinical) care for PMBC survivors, and to determine potential effective intervention strategies.MethodsThe expert panel consisted of oncology Health Care Professionals (HCPs) (N = 57), patient advocates (N = 5), and PMBC survivors (N = 38). They completed three questionnaires: Q1—idea generation; Q2—validation and prioritization; Q3—ranking. The Behavior Change Wheel was used as theoretical framework for analysis. Thematic analysis was applied to identify key overarching themes based on the top-ranked facilitators and barriers. Potential Behavior Change Techniques (BCTs) and intervention strategies were identified using the Behavior Change Technique Taxonomy version 1 and the Behavior Change Wheel.ResultsEleven core categories of key barriers/facilitators for the promotion of adherence to recommendations for lifestyle and bodyweight among PMBC survivors were identified. For each core category, relevant BCTs and practical potential intervention strategies were selected based on suggestions from the expert panel. These included: increasing knowledge about the link between lifestyle and cancer; enabling self-monitoring of lifestyle behaviors followed by evaluation; offering group lifestyle counseling for PMBC survivors, enhancing social support for favorable lifestyle behaviors; and stimulating multidisciplinary collaboration among HCPs.ConclusionsFindings provide valuable insight for the development of interventions changing behavior of PMBC survivors and HCPs toward increased healthy lifestyle (support) behavior

    The interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons

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    We have studied the interaction of polyaromatic hydrocarbons (PAHs) with the basal plane of graphite using thermal desorption spectroscopy. Desorption kinetics of benzene, naphthalene, coronene and ovalene at sub-monolayer coverages yield activation energies of 0.50 eV, 0.85 eV, 1.40 eV and 2.1 eV, respectively. Benzene and naphthalene follow simple first order desorption kinetics while coronene and ovalene exhibit fractional order kinetics owing to the stability of 2-D adsorbate islands up to the desorption temperature. Pre-exponential frequency factors are found to be in the range 101410^{14}-1021s−110^{21} s^{-1} as obtained from both Falconer--Madix (isothermal desorption) analysis and Antoine's fit to vapour pressure data. The resulting binding energy per carbon atom of the PAH is 52±52\pm5 meV and can be identified with the interlayer cohesive energy of graphite. The resulting cleavage energy of graphite is 61±561\pm5~meV/atom which is considerably larger than previously reported experimental values.Comment: 8 pages, 4 figures, 2 table

    Procalcitonin as a potent marker of bacterial infection in febrile Afro-Caribbean patients at the emergency department

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    Procalcitonin (PCT) has been shown to be of additional value in the work-up of a febrile patient. This study is the first to investigate the additional value of PCT in an Afro-Caribbean febrile population at the emergency department (ED) of a general hospital. Febrile patients were included at the ED. Prospective, blinded PCT measurements were performed in patients with a microbiologically or serologically confirmed diagnosis or a strongly suspected diagnosis on clinical grounds. PCT analysis was performed in 93 patients. PCT levels differentiated well between confirmed bacterial and confirmed viral infection (area under the curve [AUC] of 0.82, sensitivity 85%, specificity 69%, cut-off 0.24 ng/mL), between confirmed bacterial infection and non-infectious fever (AUC of 0.84, sensitivity 90%, specificity 71%, cut-off 0.21 ng/mL) and between all bacterial infections (confirmed and suspected) and non-infectious fever (AUC of 0.80, sensitivity 85%, specificity 71%, cut-off 0.21 ng/mL). C-reactive protein (CRP) levels were shown to be less accurate when comparing the same groups. This is the first study showing that, in a non-Caucasian febrile population at the ED, PCT is a more valuable marker of bacterial infection than CRP. These results may improve diagnostics and eventually decrease antibiotic prescriptions in resource-limited settings
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