5,436 research outputs found

    How Do Consumers Use Nutrition Labels on Food Products in the United States?

    Get PDF
    This study examined how consumers use food labels in the United States. Based on the results from the cluster analysis, eight nutrition label questions from the Health and Diet Survey fell into 2 categories of label usage: for shopping or for dietary decisions. Survey respondents reported equal or more consideration of nutrition-label information for dietary choices than for shopping decisions in 2008 compared with prior survey years. Female consumers, frequent label users, well-educated, consumers aged 50 to 59, or consumers with any health issues were significantly more likely to use food labels for all kinds of purposes than their corresponding counterparts

    Reliability modelling of PEM fuel cells with hybrid Petri nets

    Get PDF
    In this paper, a novel model for dynamic reliability analysis of a PEM fuel cell system is developed using Modelica language in order to account for multi-state dynamics and aging. The modelling approach constitutes the combination of physical and stochastic sub-models with shared variables. The physical model consist of deterministic calculations of the system state described by variables such as temperature, pressure, mass flow rates and voltage output. Additionally, estimated component degradation rates are also taken into account. The non-deterministic model, on the other hand, is implemented with stochastic Petri nets which represent different events that can occur at random times during fuel cell lifetime. A case study of effects of a cooling system on fuel cell performance was investigated. Monte Carlo simulations of the process resulted in a distribution of system parameters, thus providing an estimate of best and worst scenarios of a fuel cell lifetime

    Differential activation of DNA-PK based on DNA strand orientation and sequence bias

    Get PDF
    DNA-PKcs and Ku are essential components of the complex that catalyzes non-homologous end joining (NHEJ) of DNA double-strand breaks (DSBs). Ku, a heterodimeric protein, binds to DNA ends and facilitates recruitment of the catalytic subunit, DNA-PKcs. We have investigated the effect of DNA strand orientation and sequence bias on the activation of DNA-PK. In addition, we assessed the effect of the position and strand orientation of cisplatin adducts on kinase activation. A series of duplex DNA substrates with site-specific cisplatin–DNA adducts placed in three different orientations on the duplex DNA were prepared. Terminal biotin modification and streptavidin (SA) blocking was employed to direct DNA-PK binding to the unblocked termini with a specific DNA strand orientation and cisplatin–DNA adduct position. DNA-PK kinase activity was measured and the results reveal that DNA strand orientation and sequence bias dramatically influence kinase activation, only a portion of which could be attributed to Ku-DNA binding activity. In addition, cisplatin–DNA adduct position resulted in differing degrees of inhibition depending on distance from the terminus as well as strand orientation. These results highlight the importance of how local variations in DNA structure, chemistry and sequence influence DNA-PK activation and potentially NHEJ

    Retrospective Cohort Study of Antenatal Care and Pregnancy Outcomes in Kadjebi District of Ghana

    Get PDF
    Antenatal care is essential strategy for improving maternal and pregnancy outcome. We determined the association between antenatal attendance and pregnancy outcome using low birth weight and preterm birth. We conducted retrospective cohort study using data from antenatal and delivery records of all the maternity units in Kadjebi District from October 2012 to January 2013. The study subjects were a cohort of women who delivered in maternity units in the district from 1st January to 31st December 2011.The study participants were 663 pregnant women with mean age of 25.8 years, ranging between 15-45 years. Most of the women, 53.9% were between 20-29 years and 16.2% were teenagers. The mean parity of the women was 2.1. Almost all the pregnant women, 99.2% had at least one antenatal care but only 48.2% of them made the optimum antenatal visits recommended by WHO. About 55.5% of the deliveries were preterm. Pregnant women with height <145cm were most likely to have good antenatal attendance (LR, OR:  0.65, CI: 0.45-0.95, P= 0.0246). Preterm delivery was more among Sickling positive pregnant women (LR, OR: 4.37, CI: 1.55-12.33, P: 0.0052). Low birth weight was most common among the unemployed (OR: 5.17, CI: 1.72-15.60, P: 0.0035). Early antenatal registration was protective against low birth weight (OR: 0.27, CI: 0.07-0.95, P: 0.0415). Analysis of data collected in the antenatal and delivery registers can yield valuable information for public health action. Antenatal attendance was almost universal however, optimum antennal visits was undesirably lower than expected. Early registration for antenatal care would reduce low birth weight and improve pregnancy outcome. Keywords: Ghana, Antenatal care, Prenatal care, Retrospect cohort study, pregnancy outcom

    Macrophage transactivation for chemokine production identified as a negative regulator of granulomatous inflammation using agent-based modeling

    Get PDF
    Cellular activation in trans by interferons, cytokines and chemokines is a commonly recognized mechanism to amplify immune effector function and limit pathogen spread. However, an optimal host response also requires that collateral damage associated with inflammation is limited. This may be particularly so in the case of granulomatous inflammation, where an excessive number and / or excessively florid granulomas can have significant pathological consequences. Here, we have combined transcriptomics, agent-based modeling and in vivo experimental approaches to study constraints on hepatic granuloma formation in a murine model of experimental leishmaniasis. We demonstrate that chemokine production by non-infected Kupffer cells in the Leishmania donovani-infected liver promotes competition with infected KCs for available iNKT cells, ultimately inhibiting the extent of granulomatous inflammation. We propose trans-activation for chemokine production as a novel broadly applicable mechanism that may operate early in infection to limit excessive focal inflammation

    A Complete Pathway Model for Lipid A Biosynthesis in Escherichia coli

    Get PDF
    Lipid A is a highly conserved component of lipopolysaccharide (LPS), itself a major component of the outer membrane of Gram-negative bacteria. Lipid A is essential to cells and elicits a strong immune response from humans and other animals. We developed a quantitative model of the nine enzyme-catalyzed steps ofEscherichia colilipid A biosynthesis, drawing parameters from the experimental literature. This model accounts for biosynthesis regulation, which occurs through regulated degradation of the LpxC and WaaA (also called KdtA) enzymes. The LpxC degradation signal appears to arise from the lipid A disaccharide concentration, which we deduced from prior results, model results, and new LpxK overexpression results. The model agrees reasonably well with many experimental findings, including the lipid A production rate, the behaviors of mutants with defective LpxA enzymes, correlations between LpxC half-lives and cell generation times, and the effects of LpxK overexpression on LpxC concentrations. Its predictions also differ from some experimental results, which suggest modifications to the current understanding of the lipid A pathway, such as the possibility that LpxD can replace LpxA and that there may be metabolic channeling between LpxH and LpxB. The model shows that WaaA regulation may serve to regulate the lipid A production rate when the 3-deoxy-D-manno-oct-2-ulosonic acid (KDO) concentration is low and/or to control the number of KDO residues that get attached to lipid A. Computation of flux control coefficients showed that LpxC is the rate-limiting enzyme if pathway regulation is ignored, but that LpxK is the rate-limiting enzyme if pathway regulation is present, as it is in real cells. Control also shifts to other enzymes if the pathway substrate concentrations are not in excess. Based on these results, we suggest that LpxK may be a much better drug target than LpxC, which has been pursued most often

    The heat capacity and thermodynamic functions of crystalline and liquid triptycene

    Full text link
    The heat capacity of the propeller-shaped molecule triptycene (C20H14) was measured from 5 to 550 K. No anomaly other than melting was apparent, and the sample (99.999 per cent pure, as determined by analysis of the melting curve) melted at 527.18 K ([Delta]mS = 13.73 cal mol-1 K-1). The crystal density, determined from X-ray measurements, was 1.227 g cm-3. A comparison of the heat capacity of triptycene with that of bicyclo[2.2.2]octane showed that the two were simply related at low temperatures, but that the comparison was not valid beyond 164.25 K where bicyclo-octane has a transition to a restricted-rotor phase. The values of Cp, So (Ho - H0o)/T, and -(Go - H0o)/T for triptycene at 298.15 K were found to be 67.56, 65.48, 33.23, and -32.25 cal mol-1 K-1.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32841/1/0000217.pd
    • …
    corecore