Reactors for microbial electrobiotechnology

From the first electromicrobial experiment to a sophisticated microbial electrochemical process - it all takes place in a reactor. Whereas the reactor design and materials used strongly influence the obtained results, there are no common platforms for MES reactors. This is a critical convention gap, as cross-comparison and benchmarking among MES as well as MES vs. conventional biotechnological processes is needed. Only knowledge driven engineering of MES reactors will pave the way to application and commercialization. In this chapter we first assess the requirements on reactors to be used for bioelectrochemical systems as well as potential losses caused by the reactor design. Subsequently, we compile the main types and designs of reactors used for MES so far, starting from simple H-cells to stirred tank reactors. We conclude with a discussion on the weaknesses and strengths of the existing types of reactors for bioelectrochemical systems that are scored on design criteria and draw conclusions for the future engineering of MES reactors. [GRAPHICS]

Asymmetrische Polanordnung als fertigungsoptimierte Methode der Nutrastmomentreduzierung am Beispiel eines permanentmagnetisch erregten Synchrongenerators für Kleinwindenergieanlagen

In diesem Beitrag wird eine fertigungsoptimierte Methode der Nutrastmomentreduzierung durch Magnetverschiebung am Beispiel eines Synchrongenerators für Kleinwindenergieanlagen mit in die Läuferoberfläche eingelassenen Permanentmagneten vorgestellt. Auf Grundlage der Drehfeldtheorie wird ein analytisches Berechnungsmodell unter Einbezug der Magnetverschiebung zur Bestimmung des Nutrastmoments entwickelt und mit FEM-Simulationen verifiziert. Durch experimentelle Untersuchung eines gefertigten Prototyps wird der optimierende Effekt der Magnetverschiebung nachgewiesen und mit einem Referenzläufer mit ungeschrägt, symmetrisch verteilten Polen verglichen. Abschließend werden mögliche Ursachen für die verbleibenden Abweichungen identifiziert und Ansätze für die weiteren Betrachtungen abgeleitet.A production-optimized method of reducing cogging torque by magnet shifting using the example of a synchronous generator for small wind turbines with a rotor with inset surface magnets is proposed in this paper. On the basis of rotating field theory an analytical calculation model is developed taking into account the magnet shifting for determination of cogging torque. The analytical results are verified with FEM simulations. By experimental investigation of a manufactured prototype, the optimizing effect of magnet shifting is verified and compared to a rotor with symmetrically distributed poles. Finally, possible reasons for remaining discrepancies are identified and approaches for further considerations are presented

Application of gas diffusion electrodes in bioeconomy: An update

The transition of today's fossil fuel based chemical industry toward sustainable production requires improvement of established production processes as well as development of new sustainable and bio-based synthesis routes within a circular economy. Thereby, the combination of electrochemical and biotechnological advantages in such routes represents one important keystone. For the electrochemical generation of reactants from gaseous substrates such as O2 or CO2, gas diffusion electrodes (GDE) represent the electrodes of choice since they overcome solubility-based mass transport limitations. Within this article, we illustrate the architecture, function principle and fabrication of GDE. We highlight the application of GDE for conversion of CO2 using abiotic catalysts for subsequent biosynthesis as well as the application of microbial catalysts at GDE for CO2 conversion. The reduction of oxygen at GDE is summarized for the application of oxygen depolarized cathodes in microbial fuel cells and generation of H2O2 to drive enzymatic reactions. Finally, engineering aspects such as scale-up and the modeling of GDE-based processes are described. This review presents an update on the application of GDE in bio-based production systems and emphasizes their large potential for sustainable development of new pathways in bioeconomy

Physician antipsychotic overprescribing letters and cognitive, behavioral, and physical health outcomes among people with dementia: a secondary analysis of a randomized clinical trial

Importance Antipsychotics, such as quetiapine, are frequently prescribed to people with dementia to address behavioral symptoms but can also cause harm in this population. Objective To determine whether warning letters to high prescribers of quetiapine can successfully reduce its use among patients with dementia and to investigate the impacts on patients’ health outcomes. Design, Setting, and Participants This is a secondary analysis of a randomized clinical trial of overprescribing letters that began in April 2015 and included the highest-volume primary care physician (PCP) prescribers of quetiapine in original Medicare. Outcomes of patients with dementia were analyzed in repeated 90-day cross-sections through December 2018. Analyses were conducted from September 2021 to February 2024. Interventions PCPs were randomized to a placebo letter or 3 overprescribing warning letters stating that their prescribing of quetiapine was high and under review by Medicare. Main Outcomes and Measures The primary outcome of this analysis was patients’ total quetiapine use in days per 90-day period (the original trial primary outcome was total quetiapine prescribing by study PCPs). Prespecified secondary outcomes included measures of cognitive function and behavioral symptoms from nursing home assessments, indicators of depression from screening questionnaires in assessments and diagnoses in claims, metabolic diagnoses derived from assessments and claims, indicators of use of the hospital and other health care services, and death. Outcomes were analyzed separately for patients living in nursing homes and in the community. Results Of the 5055 study PCPs, 2528 were randomized to the placebo letter, and 2527 were randomized to the 3 warning letters. A total of 84 881 patients with dementia living in nursing homes and 261 288 community-dwelling patients with dementia were attributed to these PCPs. There were 92 874 baseline patients (mean [SD] age, 81.5 [10.5] years; 64 242 female [69.2%]). The intervention reduced quetiapine use among both nursing home patients (adjusted difference, –0.7 days; 95% CI, −1.3 to −0.1 days; P = .02) and community-dwelling patients (adjusted difference, −1.5 days; 95% CI, −1.8 to −1.1 days; P < .001). There were no detected adverse effects on cognitive function (cognitive function scale adjusted difference, 0.01; 95% CI, −0.01 to 0.03; P = .19), behavioral symptoms (agitated or reactive behavior adjusted difference, −0.2%; 95% CI −1.2% to 0.8% percentage points; P = .72), depression, metabolic diagnoses, or more severe outcomes, including hospitalization and death. Conclusions and Relevance This study found that overprescribing warning letters to PCPs safely reduced quetiapine prescribing to their patients with dementia. This intervention and others like it may be useful for future efforts to promote guideline-concordant care

Microbial fuel cells: From fundamentals to applications. A review

© 2017 The Author(s) In the past 10–15 years, the microbial fuel cell (MFC) technology has captured the attention of the scientific community for the possibility of transforming organic waste directly into electricity through microbially catalyzed anodic, and microbial/enzymatic/abiotic cathodic electrochemical reactions. In this review, several aspects of the technology are considered. Firstly, a brief history of abiotic to biological fuel cells and subsequently, microbial fuel cells is presented. Secondly, the development of the concept of microbial fuel cell into a wider range of derivative technologies, called bioelectrochemical systems, is described introducing briefly microbial electrolysis cells, microbial desalination cells and microbial electrosynthesis cells. The focus is then shifted to electroactive biofilms and electron transfer mechanisms involved with solid electrodes. Carbonaceous and metallic anode materials are then introduced, followed by an explanation of the electro catalysis of the oxygen reduction reaction and its behavior in neutral media, from recent studies. Cathode catalysts based on carbonaceous, platinum-group metal and platinum-group-metal-free materials are presented, along with membrane materials with a view to future directions. Finally, microbial fuel cell practical implementation, through the utilization of energy output for practical applications, is described

Hybrid cosmic ray measurements using the IceAct telescopes in coincidence with the IceCube and IceTop detectors

IceAct is a proposed surface array of compact (50 cm diameter) and cost-effective Imaging Air Cherenkov Telescopes installed at the site of the IceCube Neutrino Observatory at the geographic South Pole. Since January 2019, two IceAct telescope demonstrators, featuring 61 silicon photomultiplier (SiPM) pixels have been taking data in the center of the IceTop surface array during the austral winter. We present the first analysis of hybrid cosmic ray events detected by the IceAct imaging air-Cherenkov telescopes in coincidence with the IceCube Neutrino Observatory, including the IceTop surface array and the IceCube in-ice array. By featuring an energy threshold of about 10 TeV and a wide field-of-view, the IceAct telescopes show promising capabilities of improving current cosmic ray composition studies: measuring the Cherenkov light emissions in the atmosphere adds new information about the shower development not accessible with the current detectors, enabling significantly better primary particle type discrimination on a statistical basis. The hybrid measurement also allows for detailed feasibility studies of detector cross-calibration and of cosmic ray veto capabilities for neutrino analyses. We present the performance of the telescopes, the results from the analysis of two years of data, and an outlook of a hybrid simulation for a future telescope array

Measuring the Neutrino Cross Section Using 8 years of Upgoing Muon Neutrinos Observed with IceCube

The IceCube Neutrino Observatory detects neutrinos at energies orders of magnitude higher than those available to current accelerators. Above 40 TeV, neutrinos traveling through the Earth will be absorbed as they interact via charged current interactions with nuclei, creating a deficit of Earth-crossing neutrinos detected at IceCube. The previous published results showed the cross section to be consistent with Standard Model predictions for 1 year of IceCube data. We present a new analysis that uses 8 years of IceCube data to fit the ν$_{μ}$ absorption in the Earth, with statistics an order of magnitude better than previous analyses, and with an improved treatment of systematic uncertainties. It will measure the cross section in three energy bins that span the range 1 TeV to 100 PeV. We will present Monte Carlo studies that demonstrate its sensitivity