Emergent behaviour in a chlorophenol-mineralising three-tiered microbial `food web'

Anaerobic digestion enables the water industry to treat wastewater as a resource for generating energy and recovering valuable by-products. The complexity of the anaerobic digestion process has motivated the development of complex models. However, this complexity makes it intractable to pin-point stability and emergent behaviour. Here, the widely used Anaerobic Digestion Model No. 1 (ADM1) has been reduced to its very backbone, a syntrophic two-tiered microbial food chain and a slightly more complex three-tiered microbial food web, with their stability analysed as function of the inflowing substrate concentration and dilution rate. Parameterised for phenol and chlorophenol degradation, steady-states were always stable and non-oscillatory. Low input concentrations of chlorophenol were sufficient to maintain chlorophenol- and phenol-degrading populations but resulted in poor conversion and a hydrogen flux that was too low to sustain hydrogenotrophic methanogens. The addition of hydrogen and phenol boosted the populations of all three organisms, resulting in the counterintuitive phenomena that (i) the phenol degraders were stimulated by adding hydrogen, even though hydrogen inhibits phenol degradation, and (ii) the dechlorinators indirectly benefitted from measures that stimulated their hydrogenotrophic competitors; both phenomena hint at emergent behaviour.Comment: 19 pages, 8 figure

The tap test- an accurate First-line test for fetal lung maturity testing

Objective. To determine the accuracy of near-patient and laboratory- based fetal lung maturity tests in predicting the need for neonatal ventilation.Design. A prospective descriptive study. Subjects. One hundred high-risk obstetric patients where confirmation of fetal lung maturity would initiate delivery.Methods. Fetal weight estimation, placental maturity grading, and amniocentesis were performed. The investigators examined the amniotic fluid visually, and performed the tap test and shake test. Laboratory technicians estimated the lecithin-sphingomyelin (L/S) ratio, determined the presence of a phosphatidyl glycerol (PG) band on gel electrophoresis, and the optical density at 650 nm. Neonates delivered within 1 week of amniocentesis were included in the analysis. The primary end-point was the ability of the lung maturity tests to predict the need for neonatal ventilation.Results. Twelve of 100 neonates required ventilation. The tap test and optical density (OD) shift at 650 nm predicted the need for neonatal ventilation with the greatest accuracy.Conclusion. The tap test is a rapid, easy and accurate predictor of the need for neonatal ventilation. The OD shift at 650 nm is the laboratory-based test with the greatest accuracy in our setting

Pre-validation of the WHO organ dysfunction based criteria for identification of maternal near miss

<p>Abstract</p> <p>Background</p> <p>To evaluate the performance of the WHO criteria for defining maternal near miss and identifying deaths among cases of severe maternal morbidity (SMM) admitted for intensive care.</p> <p>Method</p> <p>Between October 2002 and September 2007, 673 women with SMM were admitted, and among them 18 died. Variables used for the definition of maternal near miss according to WHO criteria and for the SOFA score were retrospectively evaluated. The identification of at least one of the WHO criteria in women who did not die defined the case as a near miss. Organ failure was evaluated through the maximum SOFA score above 2 for each one of the six components of the score, being considered the gold standard for the diagnosis of maternal near miss. The aggregated score (Total Maximum SOFA score) was calculated using the worst result of the maximum SOFA score. Sensitivity, specificity, positive and negative predictive values of these WHO criteria for predicting maternal death and also for identifying cases of organ failure were estimated.</p> <p>Results</p> <p>The WHO criteria identified 194 cases of maternal near miss and all the 18 deaths. The most prevalent criteria among cases of maternal deaths were the use of vasoactive drug and the use of mechanical ventilation (≥1 h). For the prediction of maternal deaths, sensitivity was 100% and specificity 70.4%. These criteria identified 119 of the 120 cases of organ failure by the maximum SOFA score (Sensitivity 99.2%) among 194 case of maternal near miss (61.34%). There was disagreement in 76 cases, one organ failure without any WHO criteria and 75 cases with no failure but with WHO criteria. The Total Maximum SOFA score had a good performance (area under the curve of 0.897) for prediction of cases of maternal near miss according to the WHO criteria.</p> <p>Conclusions</p> <p>The WHO criteria for maternal near miss showed to be able to identify all cases of death and almost all cases of organ failure. Therefore they allow evaluation of the severity of the complication and consequently enable clinicians to build a plan of care or to provide an early transfer for appropriate reference centers.</p

Parametric Analysis of an Active Winglet Concept for High Aspect Ratio Wing Using CFD/CSM Computations

This paper presents a parametric analysis of an active winglet concept applied to a high aspect ratio wing. The technology studied here only consists in a single degree of freedom wing-tip whose only the cant angle deflection can be controlled. The main parameters under study are the hinge line location and its orientation with respect to the longitudinal axis of the aircraft. High-fidelity aerodynamic and structural computations are used to assess the impact of the device on both drag and loads. The influence of cant angle deflections on flutter characteristics is also evaluated. First a "wing only" configuration is studied and the results are compared with complete aircraft computations to take into account the contributions due to the trim. It is shown that the hinge line parameters highly influence the drag evolution with cant angle but with limited impact on the minimum area - in which we are interested in. Loads are significantly impacted by both cant variations and hinge line geometry. Regarding dynamic characteristics, the mode sequence is dependent on the cant deflection and massively impacts flutter onset

Development of an improved blood-stage malaria vaccine targeting the essential RH5-CyRPA-RIPR invasion complex

Reticulocyte-binding protein homologue 5 (RH5), a leading blood-stage Plasmodium falciparum malaria vaccine target, interacts with cysteine-rich protective antigen (CyRPA) and RH5-interacting protein (RIPR) to form an essential heterotrimeric “RCR-complex”. We investigate whether RCR-complex vaccination can improve upon RH5 alone. Using monoclonal antibodies (mAbs) we show that parasite growth-inhibitory epitopes on each antigen are surface-exposed on the RCR-complex and that mAb pairs targeting different antigens can function additively or synergistically. However, immunisation of female rats with the RCR-complex fails to outperform RH5 alone due to immuno-dominance of RIPR coupled with inferior potency of anti-RIPR polyclonal IgG. We identify that all growth-inhibitory antibody epitopes of RIPR cluster within the C-terminal EGF-like domains and that a fusion of these domains to CyRPA, called “R78C”, combined with RH5, improves the level of in vitro parasite growth inhibition compared to RH5 alone. These preclinical data justify the advancement of the RH5.1 + R78C/Matrix-M™ vaccine candidate to Phase 1 clinical trial

Reduction of Severe Acute Maternal Morbidity and Maternal Mortality in Thyolo District, Malawi: The Impact of Obstetric Audit

BACKGROUND: Critical incident audit and feedback are recommended interventions to improve the quality of obstetric care. To evaluate the effect of audit at district level in Thyolo, Malawi, we assessed the incidence of facility-based severe maternal complications (severe acute maternal morbidity (SAMM) and maternal mortality) during two years of audit and feedback. METHODOLOGY/PRINCIPAL FINDINGS: Between September 2007 and September 2009, we included all cases of maternal mortality and SAMM that occurred in Thyolo District Hospital, the main referral facility in the area, using validated disease-specific criteria. During two- to three-weekly audit sessions, health workers and managers identified substandard care factors. Resulting recommendations were implemented and followed up. Feedback was given during subsequent sessions. A linear regression analysis was performed on facility-based severe maternal complications. During the two-year study period, 386 women were included: 46 died and 340 sustained SAMM, giving a case fatality rate of 11.9%. Forty-five cases out of the 386 inclusions were audited in plenary with hospital staff. There was a reduction of 3.1 women with severe maternal complications per 1000 deliveries in the district health facilities, from 13.5 per 1000 deliveries in the beginning to 10.4 per 1000 deliveries at the end of the study period. The incidence of uterine rupture and major obstetric hemorrhage reduced considerably (from 3.5 to 0.2 and from 5.9 to 2.6 per 1000 facility deliveries respectively). CONCLUSIONS: Our findings indicate that audit and feedback have the potential to reduce serious maternal complications including maternal mortality. Complications like major hemorrhage and uterine rupture that require relatively straightforward intrapartum emergency management are easier to reduce than those which require uptake of improved antenatal care (eclampsia) or timely intravenous medication or HIV-treatment (peripartum infections)

Non-beneficial pediatric research : individual and social interests

Biomedical research involving human subjects is an arena of conflicts of interests. One of the most important conflicts is between interests of participants and interests of future patients. Legal regulations and ethical guidelines are instruments designed to help find a fair balance between risks and burdens taken by research subjects and development of knowledge and new treatment. There is an universally accepted ethical principle, which states that it is not ethically allowed to sacrifice individual interests for the sake of society and science. This is the principle of precedence of individual. But there is a problem with how to interpret the principle of precedence of individual in the context of research without prospect of future benefit involving children. There are proposals trying to reconcile non-beneficial research involving children with the concept of the best interests. We assert that this reconciliation is flawed and propose an interpretation of the principle of precedence of individual as follows: not all, but only the most important interests of participants, must be guaranteed; this principle should be interpreted as the secure participant standard. In consequence, the issue of permissible risk ceiling becomes ethically crucial in research with incompetent subjects