The deterministic Kermack-McKendrick model bounds the general stochastic epidemic

We prove that, for Poisson transmission and recovery processes, the classic Susceptible $\to$ Infected $\to$ Recovered (SIR) epidemic model of Kermack and McKendrick provides, for any given time $t>0$, a strict lower bound on the expected number of suscpetibles and a strict upper bound on the expected number of recoveries in the general stochastic SIR epidemic. The proof is based on the recent message passing representation of SIR epidemics applied to a complete graph

Monocyte urokinase expression: modulation by interleukins

This study delineates the regulatory effect of interleukin‐1 (IL‐1) and interleukin‐2 (IL‐2) on monocyte plasminogen activator (PA) activity. Mononuclear phagocytes regulate net PA activity by modulating the expression of urokinase‐type PA (uPA) and a specific plasminogen activator inhibitor, PA1‐2. To understand the regulation of mononuclear phagocyte PA activity, it is important to compare the expression of uPA and PAI‐2. In this study, we determined the relative abundance of secreted PA and PA inhibitor activity in human monocyte‐conditioned medium after stimulation with human recombinant IL‐1 or IL‐2. In agreement with our previous description of tumor necrosis factor‐α and interferon‐ γ stimulation of mononuclear phagocytes, we found no detectable PA activity in conditioned medium. Both IL‐1 and IL‐2 had dose‐dependent effects, significantly up‐ regulating PA inhibitor activity in monocyte‐conditioned medium (up to 11‐fold). To further investigate the mechanism underlying this effect, Northern blot analysis was done to measure steady‐state mRNA for uPA and PAI‐2. Consistent with the increase in secreted PA inhibitor activity, we found that both IL‐1 and IL‐2 significantly increased steady‐state mRNA for PAI‐2. In addition, however, both IL‐1 and IL‐2 increased steady‐state mRNA for uPA. IL‐1 appears to increase mRNA for uPA to a greater extent than does IL‐2. We conclude that IL‐1 and IL‐2 modulate monocyte proteolytic activity by increasing expression of uPA and PAI‐2 with a resultant predominance of PAI‐2. We further conclude that cytokine‐specific regulation of plasminogen activity is achieved partly by varying the proportionate expression of uPA and PAI‐2.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141561/1/jlb0598.pd

Effect of HIV-1 infection on T-Cell-based and skin test detection of tuberculosis infection

RATIONALE: Two forms of the IFN-gamma release assay (IFNGRA) to detect tuberculosis infection are available, but neither has been evaluated in comparable HIV-infected and uninfected persons in a high tuberculosis incidence environment. OBJECTIVE: To compare the ability of the T-SPOT.TB (Oxford Immunotec, Abingdon, UK), QuantiFERON-TB Gold (Cellestis, Melbourne, Australia), and Mantoux tests to identify latent tuberculosis in HIV-infected and uninfected persons. METHODS: A cross-sectional study of 160 healthy adults without active tuberculosis attending a voluntary counseling and testing center for HIV infection in Khayelitsha, a deprived urban South African community with an HIV antenatal seroprevalence of 33% and a tuberculosis incidence of 1,612 per 100,000. MEASUREMENTS AND MAIN RESULTS: One hundred and sixty (74 HIV(+) and 86 HIV(-)) persons were enrolled. A lower proportion of Mantoux results was positive in HIV-infected subjects compared with HIV-uninfected subjects (p < 0.01). By contrast, the proportion of positive IFNGRAs was not significantly different in HIV-infected persons for the T-SPOT.TB test (52 vs. 59%; p = 0.41) or the QuantiFERON-TB Gold test (43 and 46%; p = 0.89). Fair agreement between the Mantoux test (5- and 10-mm cutoffs) and the IFNGRA was seen in HIV-infected people (kappa = 0.52-0.6). By contrast, poor agreement between the Mantoux and QuantiFERON-TB Gold tests was observed in the HIV-uninfected group (kappa = 0.07-0.30, depending on the Mantoux cutoff). The pattern was similar for T-SPOT.TB (kappa = 0.18-0.24). Interpretation: IFNGRA sensitivity appears relatively unimpaired by moderately advanced HIV infection. However, agreement between the tests and with the Mantoux test varied from poor to fair. This highlights the need for prospective studies to determine which test may predict the subsequent risk of tuberculosis

Effect of substrate proximity on luminescence yield from Si nanocrystals

The influence of the proximity of a high refractive index substrate on the luminescence of Si nanocrystals was investigated by time-integrated and time-resolved photoluminescence. The luminescence yield was found to be ∼2.5 times larger for emitters distanced from the substrate compared to those in proximity with the substrate, while luminescence decay measurements revealed only a slight increase in the luminescence lifetime (∼15%). Results are discussed in terms of local density of optical modes surrounding a pointlike light emitter with important implications for the collection efficiency of luminescence and the estimation of internal quantum efficiency for a quantum dot.Support for this work was provided by the Swedish Research Council VR and the Australian Research Council ARC

Effect of Time of Access to Pasture and the Provision of a Total Mixed Ration on the Performance and Methane Production of High Yielding Dairy Cows

Allowing cows to spend time on pasture may improve their welfare, although high yielding cows are unable to consume sufficient amounts of grass to maintain milk yield and require supplementation (Charlton et al. 2011). The inclusion of grass in the diet of high yielding cows may have benefits as grass contains polyunsaturated fatty acids which can reduce methane production (Martin et al. 2008). Additionally, the soluble carbohydrate content in grass is higher in the afternoon which may increase intake (Trevaskis et al. 2004). The aim of the experiment was to determine the effects of timing of pasture access and the provision of access to total mixed ration (TMR) when at grass on the performance and methane production of high yielding dairy cows

Feeding behaviour, risk-sensitivity and response control:Effects of 5-HT2C receptor manipulations

People, like animals, tend to choose the variable option when given the choice between a fixed and variable delay to reward where, in the variable delay condition, some rewards are available immediately (Laura-Jean et al. 2019 Phil. Trans. R. Soc. B374, 20180141. (doi:10.1098/rstb.2018.0141)). This bias has been suggested to reflect evolutionary pressures resulting from food scarcity in the past placing a premium on obtaining food quickly that can win out against the risks of sometimes sustaining longer delays to food. The psychologies mediating this effect may become maladaptive in the developed world where food is readily available contributing, potentially, to overeating and obesity. Here, we report our development of a novel touchscreen task in mice allowing comparisons of the impact of food delay and food magnitude across species. We show that mice exhibit the typical preference, as shown by humans, for variable over fixed delays to rewards but no preference when it comes to fixed versus variable reward amounts and further show that this bias is sensitive to manipulations of the 5-HT2C receptor, a key mediator of feeding and impulse control. We discuss the data in terms of the utility of the task to model the psychologies and underlying brain mechanisms impacting on feeding behaviours. This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’

Population tailored modification of tuberculosis specific interferon-gamma release assay

Objectives: Blood-based Interferon-Gamma Release Assays (IGRA) identify Mycobacterium tuberculosis (MTB) sensitisation with increased specificity, but sensitivity remains impaired in human immunodeficiency virus (HIV) infected persons. The QuantiFERON-TB Gold In-Tube test contains peptide 38e55 of Rv2654c, based on data indicating differential recognition between tuberculosis patients and BCG vaccinated controls in Europe. We aimed to fine map the T cell response to Rv2654c with the view of improving sensitivity. Methods: Interferon-gamma ELISpot assay was used in HIV uninfected persons with latent and active tuberculosis to map peptide epitopes of Rv2654c. A modified IGRA was tested in two further groups of 55 HIV uninfected and 44 HIV infected persons, recruited in South Africa. Results: The most prominently recognised peptide was between amino acids 51e65. Using p51-65 to boost the QuantiFERON-TB Gold In-Tube assay, the quantitative performance of the modified IGRA increased from 1.83 IU/ml (IQR 0.30e7.35) to 2.83 (IQR 0.28e12.2; p Z 0.002) in the HIV uninfected group. In the HIV infected cohort the percentage of positive responders increased from 57% to 64% but only after 3 months of ART (p Z ns)

Blood ethanol concentrations during and following constant‐rate intravenous infusion of alcohol

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117025/1/cpt1976192213.pd

Computational Complexity of Iterated Maps on the Interval (Extended Abstract)

The exact computation of orbits of discrete dynamical systems on the interval is considered. Therefore, a multiple-precision floating point approach based on error analysis is chosen and a general algorithm is presented. The correctness of the algorithm is shown and the computational complexity is analyzed. As a main result, the computational complexity measure considered here is related to the Ljapunow exponent of the dynamical system under consideration

Diagnosis of childhood tuberculosis and host RNA expression in Africa

Improved diagnostic tests for tuberculosis in children are needed. We hypothesized that transcriptional signatures of host blood could be used to distinguish tuberculosis from other diseases in African children who either were or were not infected with the human immunodeficiency virus (HIV