Investigating the V(IV)/V(V) electrode reaction in a vanadium redox flow battery – A distribution of relaxation times analysis

Due to the worldwide increasing energy demand and the urgency to act due to climate change, new energy storage technologies are required to balance the intermittent power supply of renewable energy sources. While the vanadium redox flow battery (VRFB) must still overcome lifetime and efficiency challenges, the technology is a promising candidate for large-scale energy storage. Thus, conducting experiments in a setup that closely mimics the operating conditions is vital for gaining new insights into the reactions and transport processes in a VRFB. We developed a novel 3D printed flow cell to study the individual half cell reactions of a VRFB under precisely controlled operating conditions. Using electrochemical impedance spectroscopy combined with the distribution of relaxation times analysis, we could identify the processes occurring in the half cell with the V(IV)/V(V) redox reaction by varying experimental parameters. We assigned peaks in different frequency ranges to the electrochemical reaction, the transport processes through the porous electrode structure, and the ion transport. This information is essential in the search for optimized operating conditions to improve the VRFB efficiency

Экспериментальное исследование процесса влагоудаления из различных типов древесной хвойной биомассы при подготовке к получению тепловой энергии.

В результате эксперимента получены результаты изменения массовой скорости испарения, коэффициента аккомодации и парциального давления для хвойных пород древесины. Получены зависимости массовой скорости испарения от температуры, массовой скорости испарения от времени испарения, а также проведен расчет коэффициента аккомодации.As a result of the experiment, the results of changes in the mass evaporation rate, accommodation coefficient and partial pressure for coniferous wood species were obtained. Dependences of the mass evaporation rate on temperature, mass evaporation rate on evaporation time, and calculation of the accommodation coefficient are obtained

Recruiting young pre-symptomatic children for a clinical trial in type 1 diabetes: insights from the Fr1da insulin intervention study

Background: Although detection of children at high risk of developing type 1 diabetes and diagnosis of early stages is possible, up to now there exists no approved therapy to delay or prevent type 1 diabetes. Thus it is vital to develop evidence-based interventions. For this a sufficient number of trial participants is crucial but difficult to obtain especially in asymptomatic children. Aim: Identifying family characteristics that lead to or impede trial participation and analyze reasons stated by families for non-participation. Methods: Participants for the Fr1da Insulin Intervention study are recruited from the Fr1da study, a population based screening for early stage type 1 diabetes in Bavaria. Families with eligible children were invited to enroll. We analyzed sex and age of the child, distance of the family to the study center in Munich and the existence of a first degree family member with type 1 as possible influential factors for study participation. We also analyzed reasons stated by families who declined study participation in a phone interview. Results: Of 146 eligible children 77 (53%) were enrolled into the trial. None of the tested family characteristics differed significantly between the enrolling and the families not participating, but in general enrolling families lived closer to the study site than families not participating. This is also reflected in the reasons given by non-participating families. The most frequent reason stated were time restrictions. The second most frequent reason was the venous blood draw. Conclusion: The factors for non-participation identified in this project need be taken into account for the design of future trials in young children to ensure proper recruitment and thus to generate valid results for medical treatment of children. More research on the reason of participation and non-participation in clinical trials is needed. Keywords: Type 1 diabetes, Trial recruitment, Trial enrollment, Infants, Children, Asymptomati

The chaperonin ATPase cycle: Mechanism of allosteric switching and movements of substrate-binding domains in GroEL

AbstractChaperonin-assisted protein folding proceeds through cycles of ATP binding and hydrolysis by the large chaperonin GroEL, which undergoes major allosteric rearrangements. Interaction between the two back-to-back seven-membered rings of GroEL plays an important role in regulating binding and release of folding substrates and of the small chaperonin GroES. Using cryo-electron microscopy, we have obtained three-dimensional reconstructions to 30 Å resolution for GroEL and GroEL–GroES complexes in the presence of ADP, ATP, and the nonhydrolyzable ATP analog, AMP-PNP. Nucleotide binding to the equatorial domains of GroEL causes large rotations of the apical domains, containing the GroES and substrate protein–binding sites. We propose a mechanism for allosteric switching and describe conformational changes that may be involved in critical steps of folding for substrates encapsulated by GroES