Chemische Triebkräfte : Von der Verbrennung zum Herzschlag

Was hat eine einfache chemische Verbrennung mit dem Herzschlag zu tun? Diese Frage soll im Rahmen einer physikalisch-chemischen Experimentalvorlesung beantwortet werden. Dabei fügen sich anscheinend weit voneinander entfernte Phänomene in ein klar strukturiertes Bild. Es wird deutlich, dass der menschliche Körper aus thermodynamischer Sicht eine biologische \u27Wärmekraftmaschine\u27 ist, deren Wirkungsgrad höher als der Wirkungsgrad mechanische Wärmekraftmaschinen (\u27Dampfmaschinen\u27). Spröde anmutende thermodynamische Sätze füllen sich mit Leben - die Begriffe \u27Energie, Wärme, Entropie\u27 werden anschaulich. Anhand einfacher Demonstrationsexperimente wird ein Bogen über 250 Jahre Forschung im Bereich der chemischen Energiewandlung gespannt

Дисульфідні зв’язки у структурно-функціональній організації протеїнів

Обговорюються сучасні уявлення про роль дисульфідного зв’язку в забезпеченні структурно-функціональних властивостей протеїнів плазми крові. Узагальнюються нові підходи до можливостей рефолдингу рекомбінантних і секреторних протеїнів. Розглянуто проблему окисного фолдингу та значення дисульфідного зв’язку для посттрансляційного «дозрівання» секреторних протеїнів у порожнині ендоплазматичного ретикулума з участю редуктазної системи ензимів.Обсуждаются современные представления о роли дисульфидной связи в обеспечении структурно-функциональних свойств протеинов плазмы крови. Обобщаются новые подходы к возможностям рефолдинга рекомбинантных и секреторных протеинов. Рассмотрены проблема окислительного фолдинга и значение дисульфидной связи для посттрансляционного «созревания» секреторных протеинов в эндоплазматическом ретикулуме с участием редуктазной системы энзимов.Modern vision about disulfide bonds role in light of providing the structural and functional properties of blood plasma proteins is proposed. New approaches concerning recombinant and secretory proteins refolding are generalized. A problem concerning oxidative folding and disulfide bonds significance for secretory protein posttranslation ripening inside of endoplasmic reticulum with reductase enzyme system participation is discussed

Multisystem proteinopathy due to a homozygous p.Arg159His VCP mutation : a tale of the unexpected

ObjectiveTo assess the clinical, radiologic, myopathologic, and proteomic findings in a patient manifesting a multisystem proteinopathy due to a homozygous valosin-containing protein gene (VCP) mutation previously reported to be pathogenic in the heterozygous state.MethodsWe studied a 36-year-old male index patient and his father, both presenting with progressive limb-girdle weakness. Muscle involvement was assessed by MRI and muscle biopsies. We performed whole-exome sequencing and Sanger sequencing for segregation analysis of the identified p.Arg159His VCP mutation. To dissect biological disease signatures, we applied state-of-the-art quantitative proteomics on muscle tissue of the index case, his father, 3 additional patients with VCP-related myopathy, and 3 control individuals.ResultsThe index patient, homozygous for the known p.Arg159His mutation in VCP, manifested a typical VCP-related myopathy phenotype, although with a markedly high creatine kinase value and a relatively early disease onset, and Paget disease of bone. The father exhibited a myopathy phenotype and discrete parkinsonism, and multiple deceased family members on the maternal side of the pedigree displayed a dementia, parkinsonism, or myopathy phenotype. Bioinformatic analysis of quantitative proteomic data revealed the degenerative nature of the disease, with evidence suggesting selective failure of muscle regeneration and stress granule dyshomeostasis.ConclusionWe report a patient showing a multisystem proteinopathy due to a homozygous VCP mutation. The patient manifests a severe phenotype, yet fundamental disease characteristics are preserved. Proteomic findings provide further insights into VCP-related pathomechanisms

The neglected influence of zinc oxide light-soaking on stability measurements of inverted organic solar cells

Although zinc oxide (ZnO) is one of the most commonly used materials for electron transport layers in organic solar cells (OSCs), it also comes with disadvantages such as the so-called light-soaking issues, i.e., its need for exposure to UV light to reach its full potential in OSCs. Here, the impact of ZnO light-soaking issues on stability measurements of OSCs is investigated. It is found that in the absence of UV light a reversible degradation occurs, which is independent of the used active layer material and accelerates at higher temperatures but can be undone with a short UV exposure. This reversible aging is attributed to the re-adsorption of oxygen, which for manufacturing reasons is trapped at the interface of ZnO, even in an oxygen-free environment. This oxygen can be removed with a UV pretreatment of the ZnO but at the expense of device efficiency and production that has to take place in an oxygen-free environment. This study establishes that stability measurements of ZnO-containing OSCs must be performed exclusively with a light source including a UV part since the usage of a simple white light source - as often reported in the literature - can lead to erroneous results

Role of Excess Bi on the Properties and Performance of BiFeO₃ Thin-Film Photocathodes

BiFeO3 (BFO) has recently been identified as a promising photocathode material for photoelectrochemical (PEC) water splitting due to its light absorption and photoelectrochemical properties. The performance-limiting factors, in particular the impact of stoichiometry on the performance, still need to be understood. The effect of the ratio of Bi/Fe in the precursor solution for sol-gel synthesis on the properties and performance of BFO thin films is investigated in this study. Thin films with a stoichiometric Bi/Fe ratio and with a 10% excess of Bi are prepared on fluorine-doped tin-oxide substrates. While bulk characterization techniques show the formation of phase-pure BFO, surface characterization techniques indicate Bi enrichment on the surface. Light absorption and band gap do not change with excess Bi, whereas the current density is two times higher for Bi excess films compared to stoichiometric films at 0.6 V vs RHE. Electrochemical impedance spectroscopy attributes this improved performance of excess Bi thin films to a lower recombination rate and a lower charge transfer resistance. The lower recombination rate is attributed to fewer Bi and O vacancies, which can act as recombination centers. Therefore, adjusting the Bi/Fe ratio is an effective strategy to enhance the PEC performance of BFO photocathodes.</p

Professional Desires and Career Decisions: Effects of Professional Interests, Role Models, and Internship in Lower Secondary School

Context: Following the social cognitive career theory of Lent, Brown, and Hackett (1994), the current study examines the effect of role models’ professions and practical internship experiences on the choice of professional environment independent of professional interests. Embedded in the Swiss context with its strong vocational training system, the paper outlines to what extent the desired professional environment is realized in the chosen apprenticeship two years later and how this realization can be predicted. The theoretical model proposes that students form direct professional experiences during their first internship(s). If those experiences are positive, students choose an apprenticeship in the same professional environment. Students have indirect (vicarious) professional experiences through their role models. If those experiences are positive, students choose an apprenticeship in the role model’s professional environment. The study examined whether, independent of professional interests, direct experiences in internships and indirect experiences through role models’ professions predict the realization of a desired professional environment in an apprenticeship. Method: The longitudinal sample consists of N = 348 seventh- and ninth-grade students from four German-speaking Swiss cantons. Professional interests and environments were measured using standardized questionnaires. The professional environments of the desired professions, the chosen apprenticeships, the role model’s professions, and the internship’s professions were coded using Holland’s (1997) interest types: realistic, investigative, artistic, social, enterprising, and conventional (RIASEC). Results: In 53% of the cases, students chose an apprenticeship in the professional environment they desired. In 53% of the cases, the chosen professional environment corresponded with the professional environment of the student’s two most important role models. In 39% of the cases, those role models were their parents. By means of logistic regression analyses, we can show that role models’ professional environments and the professional environment of the first internship influenced the realization of the desired professional environment at the end of lower secondary school, independent of the effect of the individuals’ interests. Conclusions: Results show that direct professional experiences in internships and indirect experiences of role models influence the realization of the desired professional environment, independent of professional interests. In a contextual approach, career counselling should include the role model’s profession and how it corresponds with the client’s interests and professional desires. Moreover, role models, especially parents, have a responsibility to reflect on how their goals influence students’ career choice processes

Fabrication of nanocrystalline high-entropy oxide CoNiFeCrMnOₓ thin film electrodes by dip-coating for oxygen evolution electrocatalysis

The variation of calcination conditions allows for adjusting the oxidation states and coordination sites of near-surface elements in sol–gel-derived high-entropy oxides. Optimized synthesis conditions resulted in fabrication of nanocrystalline CoNiFeCrMnOₓ thin films with 1–2 nm pores, showing low OER overpotentials of 258 mV vs. RHE at 10 mA cm⁻²

Enhancing the electrocatalytic activity of 2H-WS2 for hydrogen evolution via defect engineering

Transition metal dichalcogenides (TMDs), such as MoS2 and WS2, are promising alternative non-noble metal catalysts to drive the electrocatalytic H2 evolution reaction (HER). However, their catalytic performance is inherently limited by the small number of active sites as well as their poor electrical conductivity. Here, we grow vertically aligned 2H-WS2 on different substrates to expose their edge sites for the HER and introduce a scalable approach to tune these active sites via defect engineering. In a thermal hydrogen treatment procedure, sulfur vacancies and metallic tungsten nanoparticles are formed. The extent of desulfurization, and thus the HER activity, can be tuned via controlling the H2 annealing conditions. The obtained W/WS2-x electrocatalysts are evaluated experimentally and theoretically to arrive at a better understanding of how to modify the inherently inert 2H-WS2 for more efficient HER.</p

[Pd(2‐pymo)₂]n/Al₂O₃ as MOF Single Site Catalyst for the Selective Hydrogenation of Acetylene

Despite the great potential of metal-organic frameworks (MOFs) in catalysis, industrial applications are still scarce. This is mainly due to a lack of performance when changing from idealized lab conditions towards realistic conditions of the actual application. In this work, we demonstrate the applicability and outstanding catalytic performance of an alumina-supported [Pd(2-pymo)₂]n MOF catalyst in the selective hydrogenation of acetylene to ethylene under industrial front-end conditions. It shows a competitive performance to an industrial benchmark catalyst and even exceeds it in terms of ethane selectivity due to the combination of well-defined isolated Pd active sites and synergies due to MOF-support-interactions. The high stability was proven for up to 60 h time-on-stream and supported by XPS and XRD structural analysis

Divalent Cations and Redox Conditions Regulate the Molecular Structure and Function of Visinin-Like Protein-1

The NCS protein Visinin-like Protein 1 (VILIP-1) transduces calcium signals in the brain and serves as an effector of the non-retinal receptor guanylyl cyclases (GCs) GC-A and GC-B, and nicotinic acetyl choline receptors (nAchR). Analysis of the quaternary structure of VILIP-1 in solution reveals the existence of monomeric and dimeric species, the relative contents of which are affected but not exclusively regulated by divalent metal ions and Redox conditions. Using small-angle X-ray scattering, we have investigated the low resolution structure of the calcium-bound VILIP-1 dimer under reducing conditions. Scattering profiles for samples with high monomeric and dimeric contents have been obtained. The dimerization interface involves residues from EF-hand regions EF3 and EF4