The combustion characteristics and stable carbon isotopic compositions of irradiated organic matter: implications for terrestrial and extraterrestrial sample analysis

Exposure to ionizing radiation causes the mean combustion temperature of naturally occurring, solid, terrestrial organic matter, derived from the radiation-induced polymerization of methane, to increase

Optimization and cost estimation of microalgal lipid extraction using ozone-rich microbubbles for biodiesel production

Harvesting and extracting lipids from the microalgal biomass are the most expensive processes in biodiesel production. This study focuses on reducing the lipid extraction cost using ozone-rich microbubbles technique. The lipid extraction of Dunaliella salina slurry with methanol (1:2 v/v) was performed in a 0.2 L bioreactor at room temperature with direct ozonation (8 mg L−1). When the temperature was increased (60 ̊C) and smaller bubbles were introduced during extraction, the concentration of products increased significantly to around 156%, 88.9% and 150% for 6,10,14-trimethylpentadecan-2-one, palmitic acid and stearic acid, respectively. The energy usage for extracting D. salina lipid with ozone has been estimated to be around 2.16 MJ kg−1 dry algae (36% energy) which is a small fraction of the energy that is used in the production of biodiesel, unlike centrifugation and solvent extraction methods, which consume more than 90% of the energy

Relationship of glucose to prevalence of ECG abnormalities at baseline and to 6-yr mortality in Scottish males aged 45-64 yr

A community study of more than 3000 persons screened in the Burgh of Renfrew, Scotland, included 1134 men age 45-64 whose baseline casual glucose level was measured in 1972 and who were followed for 6 yr to determine mortality rate. A positive association was found, in univariate analysis, between baseline glucose level and prevalence of ECG abnormalities as defined both by the London Whitehall Study and the U.S. Pooling Project Study. In multivariate analyses of these cross-sectional data, an association was seen for Whitehall but not Pooling Project abnormalities. No association was found between asymptomatic hyperglycemia and coronary mortality at 6 yr, either in univariate, bivariate or multivariate analyses. The clinically-observed excess in coronary mortality among those with symptomatic diabetes mellitus was not in evidence among those with asymptomatic hyperglycemia in this group of middle-aged men.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23750/1/0000723.pd

Coupled dynamics of voltage and calcium in paced cardiac cells

We investigate numerically and analytically the coupled dynamics of transmembrane voltage and intracellular calcium cycling in paced cardiac cells using a detailed physiological model and its reduction to a three-dimensional discrete map. The results provide a theoretical framework to interpret various experimentally observed modes of instability ranging from electromechanically concordant and discordant alternans to quasiperiodic oscillations of voltage and calcium

The effects of ozone on immune function.

A review of the literature reveals that ozone (O3) exposure can either suppress or enhance immune responsiveness. These disparate effects elicited by O3 exposure depend, in large part, on the experimental design used, the immune parameters examined as well as the animal species studied. Despite the apparent contradictions, a general pattern of response to O3 exposure can be recognized. Most studies indicate that continuous O3 exposure leads to an early (days 0-3) impairment of immune responsiveness followed, with continued exposures, by a form of adaptation to O3 that results in a re-establishment of the immune response. The effects of O3 exposure on the response to antigenic stimulation also depend on the time at which O3 exposure occurred. Whereas O3 exposure prior to immunization is without effect on the response to antigen, O3 exposure subsequent to immunization suppresses the response to antigen. Although most studies have focused on immune responses in the lung, numerous investigators have provided functional and anatomical evidence to support the hypothesis that O3 exposure can have profound effects on systemic immunity

Free radical activity of industrial fibers: role of iron in oxidative stress and activation of transcription factors.

We studied asbestos, vitreous fiber (MMVF10), and refractory ceramic fiber (RCF1) from the Thermal Insulation Manufacturers' Association fiber repository regarding the following: free radical damage to plasmid DNA, iron release, ability to deplete glutathione (GSH), and activate redox-sensitive transcription factors in macrophages. Asbestos had much more free radical activity than any of the man-made vitreous fibers. More Fe3+ was released than Fe2+ and more of both was released at pH 4.5 than at pH 7.2. Release of iron from the different fibers was generally not a good correlate of ability to cause free radical injury to the plasmid DNA. All fiber types caused some degree of oxidative stress, as revealed by depletion of intracellular GSH. Amosite asbestos upregulated nuclear binding of activator protein 1 transcription factor to a greater level than MMVF10 and RCF1; long-fiber amosite was the only fiber to enhance activation of the transcription factor nuclear factor kappa B (NF kappa B). The use of cysteine methyl ester and buthionine sulfoximine to modulate GSH suggested that GSH homeostasis was important in leading to activation of transcription factors. We conclude that the intrinsic free radical activity is the major determinant of transcription factor activation and therefore gene expression in alveolar macrophages. Although this was not related to iron release or ability to deplete macrophage GSH at 4 hr, GSH does play a role in activation of NF kappa B

Cord blood transplantation recapitulates fetal ontogeny with a distinct molecular signature that supports CD4+ T-cell reconstitution

Omission of in vivo T-cell depletion promotes rapid, thymic-independent CD4+-biased T-cell recovery after cord blood transplant. This enhanced T-cell reconstitution differs from that seen after stem cell transplant from other stem cell sources, but the mechanism is not known. Here, we demonstrate that the transcription profile of naive CD4+ T cells from cord blood and that of lymphocytes reconstituting after cord blood transplantation is similar to the transcription profile of fetal CD4+ T cells. This profile is distinct to that of naive CD4+ T cells from peripheral blood and that of lymphocytes reconstituting after T-replete bone marrow transplantation. The transcription profile of reconstituting naive CD4+ T cells from cord blood transplant recipients was upregulated in the T-cell receptor (TCR) signaling pathway and its transcription factor activator protein-1 (AP-1). Furthermore, a small molecule inhibitor of AP-1 proportionally inhibited cord blood CD4+ T-cell proliferation (P < .05). Together, these findings suggest that reconstituting cord blood CD4+ T cells reflect the properties of fetal ontogenesis, and enhanced TCR signaling is responsible for the rapid restoration of the unique CD4+ T-cell biased adaptive immunity after cord blood transplantation

Genetic variance for behavioural 'predictability' of stress response.

Genetic factors underpinning phenotypic variation are required if natural selection is to result in adaptive evolution. However, evolutionary and behavioural ecologists typically focus on variation among individuals in their average trait values and seek to characterize genetic contributions to this. As a result, less attention has been paid to if and how genes could contribute towards within-individual variance or trait 'predictability'. In fact, phenotypic 'predictability' can vary among individuals, and emerging evidence from livestock genetics suggests this can be due to genetic factors. Here, we test this empirically using repeated measures of a behavioural stress response trait in a pedigreed population of wild-type guppies. We ask (a) whether individuals differ in behavioural predictability and (b) whether this variation is heritable and so evolvable under selection. Using statistical methodology from the field of quantitative genetics, we find support for both hypotheses and also show evidence of a genetic correlation structure between the behavioural trait mean and individual predictability. We show that investigating sources of variability in trait predictability is statistically tractable and can yield useful biological interpretation. We conclude that, if widespread, genetic variance for 'predictability' will have major implications for the evolutionary causes and consequences of phenotypic variation.This work was supported by the Biotechnology and Biological Sciences Research Council (grant BB/L022656/1) and by a BBSRC studentship to PMP