The differential risk of oral contraceptives: the impact of full exposure history*

Previous discussions have indicated that the small increases of risk of venous thromboembolism (VTE) associated with newer combined oral contraceptives (third generation, containing desogestrel and gestodene) may be attributed to bias due to cohort effects. In a case-control analysis, this may produce an overestimate of risk of newer preparations. In 10 centres in Germany and the UK, the Transnational Study analysed data from 502 women aged 16-44 years with VTE, and from 1864 controls matched for 5-year age group and region. Information on lifetime exposure history from all subjects was added to the dataset used in previous analyses and entered into a Cox regression model with time-dependent covariates. Based on 17 622 continuous exposure episodes comprising 47 914 person-years of observation, the adjusted hazard ratio (equivalent to odds ratio, OR) of VTE for the comparison of current users of third-generation versus current users of second-generation (primarily levonorgestrel compounds) combined oral contraceptives was 0.8 (0.5 to 1.3). The OR obtained in standard case-control analysis had been 1.5 (1.1 to 2.1). Adjustment for past exposures includes more information and appears more valid than the standard cross-sectional analysis. Using this approach, the Transnational Study data show no evidence for an increased risk of VTE with third- compared with second-generation combined oral contraceptive

Effect of sample treatment methods for PAH4 determination in cocoa

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and some have been reported to be present in cocoa. Therefore, PAHs determination in cocoa is very important. In this study, a simple procedures based on maceration extraction, solid phase extraction (SPE), saponification and high-performance liquid chromatography with fluorescence detection (HPLC-FLD) were presented for rapid PAH4 (sum of four different PAHs; benzo (a) anthracene, chrysene, benzo (b) fluoranthene, and benzo (a) pyrene) determination in cocoa samples (cocoa bean, cocoa nib and cocoa shell). The effect of using different sample extractions (different type of solvents and extraction time) and purification methods (different SPE treatments) were investigated. The most satisfactory recoveries (59.83 – 116.99% at concentration levels; 1.00, 5.00 and 10.00 µ/kg) and clean extracts were obtained by extracting the cocoa samples (cocoa nib, cocoa shell and whole cocoa bean) with hexane for two hours and purification with SPE using silica cartridge (cyclohexane as elution solvent). In this study, detection limit was in the range of 3.36 – 13.90 ng/kg thus, the method meets the Commission Regulation (EU) No. 836/2011 and may be useful to be applied for assessment of cocoa beans quality

Physiological levels of nitrate support anoxic growth by denitrification of Pseudomonas aeruginosa at growth rates reported in cystic fibrosis lungs and sputum

© 2014 Line, Alhede, Kolpen, Kuhl, Ciofu, Bjarnsholt, Moser, Toyofuku, Nomura, H0i'by and Jensen. Chronic Pseudomonas aeruginosa lung infection is the most severe complication in patients with cystic fibrosis (CF). The infection is characterised by the formation of biofilm surrounded by numerous polymorphonuclear leukocytes (PMNs) and strong O2 depletion in the endobronchial mucus. We have reported that O2 is mainly consumed by the activated PMNs, while O2 consumption by aerobic respiration is diminutive and nitrous oxide (N2O) is produced in infected CF sputum. This suggests that the reported growth rates ofP. aeruginosa in lungs and sputum may result from anaerobic respiration using denitrification. The growth rate of P. aeruginosa achieved by denitrification at physiological levels (~400 μM) of nitrate (NO3-) is however, not known. Therefore, we have measured growth rates of anoxic cultures of PAO1 and clinical isolates (n = 12) in LB media supplemented with NO3- and found a significant increase of growth when supplementing PAO1 and clinical isolates with > 150 μM NO3- and 100 μM NO3-, respectively. An essential contribution to growth by denitrification was demonstrated by the inability to establish a significantly increased growth rate by a denitrification deficient ΔnirS-N mutant at <1 mM of NO3-. Activation of denitrification could be achieved by supplementation with as little as 62.5 μM of NO3- according to the significant production of N2O by the nitrous oxide reductase deficient ΔnosZ mutant. Studies of the promoter activity, gene transcripts and enzyme activity of the four N-oxide reductases in PAO1 (Nar, Nir, Nor, Nos) further verified the engagement of denitrification, showing a transient increase in activation and expression and rapid consumption of NO3- followed by a transient increase of NO2-. Growth rates obtained by denitrification in this study were comparable to our reported growth rates in the majority of P. aeruginosa cells in CF lungs and sputum. Thus, we have demonstrated that denitrification is required for P. aeruginosa growth in infected endobronchial CF mucus

Bionic 3D printed corals.

Corals have evolved as optimized photon augmentation systems, leading to space-efficient microalgal growth and outstanding photosynthetic quantum efficiencies. Light attenuation due to algal self-shading is a key limiting factor for the upscaling of microalgal cultivation. Coral-inspired light management systems could overcome this limitation and facilitate scalable bioenergy and bioproduct generation. Here, we develop 3D printed bionic corals capable of growing microalgae with high spatial cell densities of up to 109 cells mL-1. The hybrid photosynthetic biomaterials are produced with a 3D bioprinting platform which mimics morphological features of living coral tissue and the underlying skeleton with micron resolution, including their optical and mechanical properties. The programmable synthetic microenvironment thus allows for replicating both structural and functional traits of the coral-algal symbiosis. Our work defines a class of bionic materials that is capable of interacting with living organisms and can be exploited for applied coral reef research and photobioreactor design