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We study mechanisms that can produce an increase of biomass production in batch processes when considering mixed cultures, compared to pure cultures. We show that growth thresholds or variable yields can produce 'overyielding', while this is not possible in the classical batch model with multiple species. We give sufficient conditions on the characteristics of the species to obtain overyielding, and illustrate these theoretical results with numerical simulations. This work provides new insights on species complementary in models of mixed cultures, without having to consider direct interactions terms between species as, for instance in the well known Generalized Lotka-Volterra model.

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OBJECTIVE: To assess the efficacy of doubling the 30 mg dose of iron in women with iron deficiency anemia (IDA) in singleton pregnancies. STUDY DESIGN: Prospective randomized controlled trial. Iron-deficient women were randomized during the second trimester to receive one or two capsules of daily iron supplement, containing 34 mg of ferrous sulfate, from 17 weeks until 6 weeks postpartum. The primary outcome was hemoglobin (Hgb) at 35 weeks. Secondary outcomes included ferritin at 35 weeks, Hgb during pregnancy and postpartum, birth weights, preterm birth rate, gastrointestinal side effects, intravenous iron administration and compliance. RESULTS: In all, 160 women were randomized to receive one capsule and 164 received two capsules. Both groups had similar Hgb (10.1 g dl-1) and ferritin (9.3 and 9.4 ng l-1) at allocation. Hgb concentration in both groups was similar at 35 weeks (10.8 g dl-1). There were no significant differences in any of the secondary outcomes. CONCLUSION: In IDA pregnant women, a single dose of iron is as effective as a double dose.

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We study a chemostat model in which two microbial species grow on a single resource. We show that species coexistence is possible when the species which would normally win the exclusive competition aggregates in flocs. Our mathematical analysis exploits the fact that flocculation is fast compared to biological growth, a common hypothesis in floc models. A numerical study shows the validity of this approach in a large parameter range. We indicate how our model yields a mechanistic justification for the so-called density-dependent growth.

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A robust regulation law is applied to the stabilization of a class of biochemical reactors exhibiting partially known highly nonlinear dynamic behavior. An uncertain environment with the presence of unknown inputs is considered. Based on some structural and operational conditions, this regulation law is shown to exponentially stabilize the aforementioned bioreactors around a desired set-point. This approach is experimentally applied and validated on a pilot-scale (1 m3) anaerobic digestion process for the treatment of raw industrial wine distillery wastewater where the objective is the regulation of the chemical oxygen demand (COD) by using the dilution rate as the manipulated variable. Despite large disturbances on the input COD and state and parametric uncertainties, this regulation law gave excellent performances leading the output COD towards its set-point and keeping it inside a pre-specified interval.

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This paper concentrates on the state observation in bioprocesses when there is uncertainty on the process parameters and/or the process inputs. An interval observer is designed on the basis of the cooperativity properties of the model for a standard stirred tank bioreactor model with a single microbial growth and a kinetic model depending on the substrate concentration. Further assumptions are the (lower and upper) boundedness of the specific growth rate and the inlet substrate concentration. Mathematical analysis of the stability and convergence of the interval observer is performed both in absence and in presence of uncertainty on the measurements. It is shown in particular that when the process inputs are known, the static observation error on the unknown state is inversely proportional to one of the observer gains. The performance of the interval observer are also illustrated through numerical simulation.

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This paper presents the practical implementation of a new robust interval observer on a 1 m3 continuous fixed bed anaerobic reactor used for the treatment of industrial wine distillery wastewater. This interval observer is able to generate guaranteed intervals for the unmeasured variables (i.e. acidogenic and methanogenic bacteria, alkalinity and chemical oxygen demand) from few on-line measurements (i.e. input liquid flow rate, CO2 gaseous flow rate, volatile fatty acids and total inorganic carbon). The main advantage of this approach is its independance with respect to disturbances and uncertainty in the initial conditions, in the kinetics and, last but not least, in the process inputs.

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Inositol is a key metabolite in the phosphatidylinositol cycle, which is a second messenger system for serotonin-2 receptors that have been implicated in the pathophysiology of schizophrenia. Cerebrospinal fluid inositol levels were measured in 20 schizophrenic patients and 19 age- and sex-matched controls and no difference was found. However, the patients were all neuroleptic-treated. A controlled double-blind crossover trial of 12 g daily of inositol for a month in 12 anergic schizophrenic patients, twice the dose given before in schizophrenia, did not show any beneficial effects. However, the number of patients studied was small and the length of time of inositol administration may not have been sufficient.

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Too little is known about the nature and extent of physical impairment suffered by adolescents. A recent study in Israel points the way towards more systematic data gathering and analysis, so that the necessary care can be provided.

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Inositol is a key precursor for synthesis of phosphatidylinositol in a major second messenger signalling system. It is biologically active in syndromes such as respiratory distress syndrome but has been thought to be excluded from CNS by the blood-brain barrier. Oral inositol treatment of 8 patients is shown to significantly increase CSF inositol by almost 70%, suggesting possible CNS therapeutic applications of this compound and possible CNS side-effects of systemic therapy.

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Four young patients who developed weight gain induced by carbamazepine therapy are described. The patients received the carbamazepine as anticonvulsant treatment, and soon after starting the drug, abruptly developed an increase in appetite with a concomitant increase in food intake. During a period of 2 months the patients' weights rose by between 7 and 15 kg. Dietary restriction during the carbamazepine treatment was ineffective in promoting weight loss, and loss of the excess weight was achieved only when the drug was discontinued. These patients demonstrate an as yet unpublished adverse effect of carbamazepine. In carbamazepine-induced weight gain, overeating and fat deposition must be taken into consideration as a differential diagnosis to the hitherto described water retention and edema.

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The utilization of 162 PTFE grafts for angio access in 131 patients over a three year period is reported. One hundred and three new PTFE arterio-venous fistulae were constructed in addition to 59 patch and tube incorporations into pre-existing graft fistulae. At three years, the cumulative patency of newly constructed grafts was 85%. Seventy four per cent of the grafts have had no thrombosis and are functioning up to 38 months following insertion. An aggressive approach was adopted towards the 15% of grafts that had at least one episode of thrombosis prior to flow being successfully restored. Graft occlusion which occurred up to 18 months following insertion, represented 11% of the group in this series. PTFE has provided an important advance in angio access for chronic renal failure with high patency and excellent durability after three years.

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