Aquatic Biofilms Romani, Anna M; Guasch, Helena; Balaguer, M. Dolors ...
2016, 2016-01-31
eBook
This book is a concise review of the current knowledge on aquatic biofilms with an emphasis on the characteristics and ecology of biofilms in natural ecosystems and a focus on biofilm applications ...linked to water pollution problems. The volume is divided into three sections: Biofilms Mode of Life; Biofilms and Pollution; and New Technologies using Biofilms. In the first section the aquatic biofilm mode of life is described and reviewed. Key aspects covered include the three-dimensional structure and cell to cell communication of biofilms, their dynamic prokaryotic diversity and their vital role in biogeochemical cycles. In the second part of the book the use of biofilms in water quality is comprehensively covered. Chapters discuss biofilms in water quality, environmental risk assessment, monitoring and ecotoxicological approaches. Further topics include biofilm development in sewage pipes and the potential for microbial transformations in these systems. The final section focuses on important examples of novel technologies based on biofilms for water treatment, including the biodegradation of pollutants, the application of bioelectrogenic biofilms, and the biofilm capacity for nitrogen removal. With contributions from ecologists, engineers and microbiologists this book presents scientists and technicians with up-to-date knowledge and a clear understanding of aquatic biofilms from different and complementary points of view. An essential reference book for anyone working with biofilms.
Abstract Decision making in acute chest pain remains challenging despite normal (<99th percentile) high-sensitivity troponin (hs-cTn). Some studies suggest that undetectable hs-cTn, far below the ...99th percentile, might rule out acute coronary syndrome. We investigated clinical data in comparison to undetectable hs-cTnT. The study comprised of 682 patients (November 2010/September 2011) presenting at the emergency department with chest pain and normal hs-cTnT (<14 ng/L). The main endpoint was major adverse cardiac events (MACE: death, myocardial infarction, readmission for unstable angina or revascularization) at a 4-year median follow-up; secondary endpoint was 30-day MACE. A clinical score was built by assigning points according to hazard ratios of the independent predictive variables: 1 point (male and effort-related pain), and 2 points (recurrent pain and prior ischemic heart disease).The negative predictive values of the clinical score and undetectable hs-cTnT (<5 ng/L), were tested. A total of 72 (10.6%) patients suffered long-term MACE. The C-statistics of the clinical score for long-term (0.75) and 30-day (0.88) MACE were higher than with the TIMI risk (0.68, 0.77) or GRACE (0.50, 0.47) scores. Likewise, the negative predictive values of score= 0 (97.5%, 100%) and ≤1 point (95.9%, 100%) were higher than using undetectable hs-cTnT (91.9%, 98.1%). Both a clinical score of 0 and ≤1 classified better patients at risk of MACE (p=0.0001, log rank test) than hs-cTnT<5 ng/L (p=0.06). In conclusion, clinical data can guide decision making and perform at least equally well as undetectable hs-cTnT, in patients presenting at the emergency department with chest pain and normal hs-cTnT.
Colorectal cancer(CRC)is one of the most frequent neoplasms and an important cause of mortality in the developed world.This cancer is caused by both genetic and environmental factors although 35%of ...the variation in CRC susceptibility involves inherited genetic differences.Mendelian syndromes account for about5%of the total burden of CRC,with Lynch syndrome and familial adenomatous polyposis the most common forms.Excluding hereditary forms,there is an important fraction of CRC cases that present familial aggregation for the disease with an unknown germline genetic cause.CRC can be also considered as a complex disease taking into account the common diseasecommom variant hypothesis with a polygenic model of inheritance where the genetic components of common complex diseases correspond mostly to variants of low/moderate effect.So far,30 common,low-penetrance susceptibility variants have been identified for CRC.Recently,new sequencing technologies including exomeand whole-genome sequencing have permitted to add a new approach to facilitate the identification of new genes responsible for human disease predisposition.By using whole-genome sequencing,germline mutations in the POLE and POLD1 genes have been found to be responsible for a new form of CRC genetic predisposition called polymerase proofreading-associated polyposis.
Up to date a few electroactive bacteria embedded in biofilms are described to catalyze both anodic and cathodic reactions in bioelectrochemical systems (i.e. bidirectional electron transfer). How ...these bacteria transfer electrons to or from the electrode is still uncertain. In this study the extracellular electron transfer mechanism of bacteria within an electroactive biofilm was investigated by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). First, a mature anodic electroactive biofilm was developed from an activated sludge sample (inoculum), acetate as electron donor and a poised electrode (+397mV vs. SHE). Later, this biofilm was “switched” to biocathodic conditions by feeding it with a medium containing nitrates and poising the electrode at −303mV vs. SHE. The electrochemical characterization indicated that both, acetate oxidation and nitrate reduction took place at a similar formal potential of −175±05 and −175±34mV vs. SHE, respectively. The biofilm was predominantly composed by Geobacter sp. at both experimental conditions. Taken together, the results indicated that both processes could be catalyzed by using the same electron conduit, and most likely by the same bacterial consortium. Hence, this study suggests that electroactive bacteria within biofilms could use the same electron transfer conduit for catalyzing anodic and cathodic reactions.
•Growth of electroactive biofilm able to oxidize acetate and reduce nitrate.•Electrochemical characterization of the switchable electroactive biofilm.•Bidirectional catalysis using a redox system located around −175mV vs. SHE.•Biofilm predominantly composed of Geobacter sp.
Biogas upgrading is an expanding field dealing with the increase in methane content of the biogas to produce biomethane. Biomethane has a high calorific content and can be used as a vehicle fuel or ...directly injected into the gas grid. Bioelectrochemical systems (BES) could become an alternative for biogas upgrading, by which the yield of the process in terms of carbon utilisation could be increased. The simulated effluent from a water scrubbing-like unit was used to feed a BES. The BES was operated with the biocathode poised at -800 mV vs.SHE to drive the reduction of the CO sub(2) fraction of the biogas into methane. The BES was operated in batch mode to characterise methane production and under continuous flow to demonstrate its long-term viability. The maximum methane production rate obtained during batch tests was 5.12 plus or minus 0.16 mmol m super(-2) per day with a coulombic efficiency (CE) of 75.3 plus or minus 5.2%. The production rate increased to 15.35 mmol m super(-2) per day (CE of 68.9 plus or minus 0.8%) during the continuous operation. Microbial community analyses and cyclic voltammograms showed that the main mechanism for methane production in the biocathode was hydrogenotrophic methanogenesis by Methanobacteriumsp., and that electromethanogenesis occurred to a minor extent. The presence of other microorganisms in the biocathode, such as Methylocystissp. revealed the presence of side reactions, such as oxygen diffusion from the anode compartment, which decreased the efficiency of the BES. The results of the present work offer the first experimental report on the application of BES in the field of biogas upgrading processes.
Hydrogen represents a promising clean fuel for future applications. The biocathode of a two-chambered microbial electrolysis cell (biotic MEC) was studied and compared with an abiotic cathode ...(abiotic MEC) in order to assess the influence of naturally selected microorganisms for hydrogen production in a wide range of cathode potentials (from −400 to −1800 mV vs SHE). Hydrogen production in both MECs increased when cathode potential was decreased. Microorganisms present in the biotic MEC were identified as Hoeflea sp. and Aquiflexum sp. Supplied energy was utilized more efficiently in the biotic MEC than in the abiotic, obtaining higher hydrogen production respect to energy consumption. At −1000 mV biotic MEC produced 0.89 ± 0.10 m3 H2 d−1 m−3NCC (Net Cathodic Compartment) at a minimum operational cost of 3.2 USD kg−1 H2. This cost is lower than the estimated market value for hydrogen (6 USD kg−1 H2).
•Cathode potential drives hydrogen production.•Energy requirements to produce hydrogen are lower in a biotic than an abiotic MEC.•The feasibility of a cost-effective biocathode was proved (3.2 USD kg−1 H2).•Bacteria present in a biocathode were identified as Aquiflexum sp. and Hoeflea sp.
Les Pyrénées témoignent de la vigueur des échanges : les populations y commercent en toutes circonstances. Les sources font état d’échanges sur chacun des versants et entre le nord et le sud de la ...chaîne, et mettent en évidence un négoce transpyrénéen intéressant des marchés plus larges où la montagne et ses hommes ne participent qu’au transit des produits. Si une première approche permet d’entrevoir globalement le trafic, un certain nombre de questions se pose sur sa nature précise, l’influence des marches de part et d’autre des Pyrénées ou le rôle des marchands. Réunissant des chercheurs venus des deux côtés des Pyrénées, ces journées se fixent comme objectif de tester toutes les approches du sujet sous l’angle de l’histoire économique, sociale, culturelle, anthropologique et juridique.
To determine the effects of behavioural interventions in people with oropharyngeal dysphagia.
Systematic literature searches were conducted to retrieve randomized controlled trials in four different ...databases (CINAHL, Embase, PsycINFO, and PubMed). The methodological quality of eligible articles was assessed using the Revised Cochrane risk-of-bias tool for randomised trials (RoB 2), after which meta-analyses were performed using a random-effects model.
A total of 37 studies were included. Overall, a significant, large pre-post interventions effect size was found. To compare different types of interventions, all behavioural interventions and conventional dysphagia treatment comparison groups were categorised into compensatory, rehabilitative, and combined compensatory and rehabilitative interventions. Overall, significant treatment effects were identified favouring behavioural interventions. In particular, large effect sizes were found when comparing rehabilitative interventions with no dysphagia treatment, and combined interventions with compensatory conventional dysphagia treatment. When comparing selected interventions versus conventional dysphagia treatment, significant, large effect sizes were found in favour of Shaker exercise, chin tuck against resistance exercise, and expiratory muscle strength training.
Behavioural interventions show promising effects in people with oropharyngeal dysphagia. However, due to high heterogeneity between studies, generalisations of meta-analyses need to be interpreted with care.
To assess the effects of brain neurostimulation (i.e., repetitive transcranial magnetic stimulation rTMS and transcranial direct current stimulation tDCS) in people with oropharyngeal dysphagia (OD).
...Systematic literature searches were conducted in four electronic databases (CINAHL, Embase, PsycINFO, and PubMed) to retrieve randomised controlled trials (RCTs) only. Using the Revised Cochrane risk-of-bias tool for randomised trials (RoB 2), the methodological quality of included studies was evaluated, after which meta-analysis was conducted using a random-effects model.
In total, 24 studies reporting on brain neurostimulation were included: 11 studies on rTMS, 9 studies on tDCS, and 4 studies on combined neurostimulation interventions. Overall, within-group meta-analysis and between-group analysis for rTMS identified significant large and small effects in favour of stimulation, respectively. For tDCS, overall within-group analysis and between-group analysis identified significant large and moderate effects in favour of stimulation, respectively.
Both rTMS and tDCS show promising effects in people with oropharyngeal dysphagia. However, comparisons between studies were challenging due to high heterogeneity in stimulation protocols and experimental parameters, potential moderators, and inconsistent methodological reporting. Generalisations of meta-analyses need to be interpreted with care. Future research should include large RCTs using standard protocols and reporting guidelines as achieved by international consensus.
Background Serrated cancers account for 10% to 20% of all colorectal cancers (CRC) and more than 30% of interval cancers. The presence of proximal serrated polyps and large (≥10 mm) serrated polyps ...(LSP) has been correlated with colorectal neoplasia. Objective To evaluate the prevalence of serrated polyps and their association with synchronous advanced neoplasia in a cohort of average-risk population and to assess the efficacy of one-time colonoscopy and a biennial fecal immunochemical test for reducing CRC-related mortality. This study focused on the sample of 5059 individuals belonging to the colonoscopy arm. Design Multicenter, randomized, controlled trial. Setting The ColonPrev study, a population-based, multicenter, nationwide, randomized, controlled trial. Patients A total of 5059 asymptomatic men and women aged 50 to 69 years. Intervention Colonoscopy. Main Outcome Measurements Prevalence of serrated polyps and their association with synchronous advanced neoplasia. Results Advanced neoplasia was detected in 520 individuals (10.3%) (CRC was detected in 27 0.5% and advanced adenomas in 493 9.7%). Serrated polyps were found in 1054 individuals (20.8%). A total of 329 individuals (6.5%) had proximal serrated polyps, and 90 (1.8%) had LSPs. Proximal serrated polyps or LSPs were associated with male sex (odds ratio OR 2.08, 95% confidence interval CI, 1.76-4.45 and OR 1.65, 95% CI, 1.31-2.07, respectively). Also, LSPs were associated with advanced neoplasia (OR 2.49, 95% CI, 1.47-4.198), regardless of their proximal (OR 4.15, 95% CI, 1.69-10.15) or distal (OR 2.61, 95% CI, 1.48-4.58) locations. When we analyzed subtypes of serrated polyps, proximal hyperplasic polyps were related to advanced neoplasia (OR 1.61, 95% CI, 1.13-2.28), although no correlation with the location of the advanced neoplasia was observed. Limitations Pathology criteria for the diagnosis of serrated polyps were not centrally reviewed. The morphology of the hyperplasic polyps (protruded or flat) was not recorded. Finally, because of the characteristics of a population-based study carried out in average-risk patients, the proportion of patients with CRC was relatively small. Conclusion LSPs, but not proximal serrated polyps, are associated with the presence of synchronous advanced neoplasia. Further studies are needed to determine the risk of proximal hyperplastic polyps.
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