Search

Abstract: We have developed double layer-type (catalyst layer/current collecting layer) oxygen electrodes (DLE) for reversible SOFCs. As the catalyst layer (cathode for SOFC and anode for steam electrolysis) interfaced with a samaria-doped ceria [(CeO2)0.8(SmO1.5)0.2, SDC] interlayer/YSZ solid electrolyte, mixed conducting La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and SDC particles were employed. The current collecting porous LSCF layer was formed on the catalyst layer. By controlling the SDC content, as well as the thickness and porosity of the catalyst layer, the gas diffusion rate and the conduction networks for electrons and oxide ions were optimized, resulting in a marked reduction of the overpotential. The LSCF+SDC/LSCF DLE exhibited higher performance than single-layer electrodes of LSCF+SDC or LSCF; the IR-free anode potential vs. an air reference electrode was 0.12V (corresponding to an overpotential of 0.08V) at 0.5Acm−2 and 900°C under an atmosphere of O2 (1atm). [Copyright &y& Elsevier]

Gelation of sulfolane-based highly concentrated electrolytes using a partially fluorinated polymer enhances the Li-ion transference number of the electrolytes because acidic protons surrounded by fluorine atoms in the polymer network trap anions, and the high Li + transference number is effective in suppressing the concentration polarization in Li batteries.

Cardiac arrhythmias stemming from abnormal sinoatrial node (SAN) function can lead to sudden death. Developing a biological pacemaker device for treating sick sinus syndrome (SSS) could offer a potential cure. Understanding SAN differentiation is crucial, yet its regulatory mechanism remains unclear. We reanalyzed published RNA-seq data and identified Odz4 as a SAN-specific candidate. In situ hybridization revealed Odz4 expression in the cardiac crescent and throughout the cardiac conduction system (CCS). To assess the role of Odz4 in CCS differentiation, we utilized a Tet-Off inducible system for its intracellular domain (ICD). Embryonic bodies (EBs) exogenously expressing Odz4-ICD exhibited an increased propensity to develop into pacemaker-like cells with enhanced automaticity and upregulated expression of SAN-specific genes. CellChat and GO analyses unveiled SAN-specific enrichment of ligand-receptor sets, especially Ptn-Ncl, and extracellular matrix components in the group exogenously expressing Odz4-ICD. Our findings underscore the significance of Odz4 in SAN development and offer fresh insights into biological pacemaker establishment., (© 2024 The Author(s). FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Background: Skeletal muscles possess unique abilities known as adaptation or plasticity. When exposed to external stimuli, such as mechanical loading, both myofiber size and myonuclear number increase. Muscle stem cells, also known as muscle satellite cells (MuSCs), play vital roles in these changes. HeyL, a direct target of Notch signaling, is crucial for efficient muscle hypertrophy because it ensures MuSC proliferation in surgically overloaded muscles by inhibiting the premature differentiation. However, it remains unclear whether HeyL is essential for MuSC expansion in physiologically exercised muscles. Additionally, the influence of myofiber type on the requirement for HeyL in MuSCs within exercised muscles remains unclear., Methods: We used a voluntary wheel running model and HeyL-knockout mice to investigate the impact of HeyL deficiency on MuSC-derived myonuclei, MuSC behavior, muscle weight, myofiber size, and myofiber type in the running mice., Results: The number of new MuSC-derived myonuclei was significantly lower in both slow-twitch soleus and fast-twitch plantaris muscles from exercised HeyL-knockout mice than in control mice. However, expect for the frequency of Type IIb myofiber in plantaris muscle, exercised HeyL-knockout mice exhibited similar responses to control mice regarding myofiber size and type., Conclusions: HeyL expression is crucial for MuSC expansion during physiological exercise in both slow and fast muscles. The frequency of Type IIb myofiber in plantaris muscle of HeyL-knockout mice was not significantly reduced compared to that of control mice. However, the absence of HeyL did not affect the increased size and frequency of Type IIa myofiber in plantaris muscles. In this model, no detectable changes in myofiber size or type were observed in the soleus muscles of either control or HeyL-knockout mice. These findings imply that the requirement for MuSCs in the wheel-running model is difficult to observe due to the relatively low degree of hypertrophy compared to surgically overloaded models., (© 2024. The Author(s).)

The sensitivity to protein inhibitors is altered by modifications or protein mutations, as represented by drug resistance. The mode of stable drug binding to the protein pocket has been experimentally clarified. However, the nature of the binding of inhibitors with reduced sensitivity remains unclear at the atomic level. In this study, we analyzed the thermodynamics and kinetics of inhibitor binding to the surface of wild-type and mutant dihydrofolate reductase (DHFR) using molecular dynamics simulations combined with Markov state modeling. A strong inhibitor of methotrexate (MTX) showed a preference for the active site of wild-type DHFR with minimal binding to unrelated (secondary) sites. Deletion of a side-chain fragment in MTX largely destabilized the active site-bound state, with clear evidence of binding to secondary sites. Similarly, the F31V mutation in DHFR diminished the specificity of MTX binding to the active site. These results reveal the presence of multiple-bound states whose stabilities are comparable to or higher than those of the unbound state, suggesting that a reduction in the binding affinity for the active site significantly elevates the fractions of these states. This study presents a theoretical model that more accurately interprets the altered drug sensitivity than the traditional two-state model.

It is widely accepted that cell fate determination in the cochlea is tightly controlled by different transcription factors (TFs) that remain to be fully defined. Here, we show that Sox9, initially expressed in the entire sensory epithelium of the cochlea, progressively disappears from differentiating hair cells (HCs) and is finally restricted to supporting cells (SCs). By performing ex vivo electroporation of E13.5-E14.5 cochleae, we demonstrate that maintenance of Sox9 expression in the progenitors committed to HC fate blocks their differentiation, even if co-expressed with Atoh1, a transcription factor necessary and sufficient to form HC. Sox9 inhibits Atoh1 transcriptional activity by upregulating Hey1 and HeyL antagonists, and genetic ablation of these genes induces extra HCs along the cochlea. Although Sox9 suppression from sensory progenitors ex vivo leads to a modest increase in the number of HCs, it is not sufficient in vivo to induce supernumerary HC production in an inducible Sox9 knockout model. Taken together, these data show that Sox9 is downregulated from nascent HCs to allow the unfolding of their differentiation program. This may be critical for future strategies to promote fully mature HC formation in regeneration approaches.

We demonstrate that tetra-arm poly(ethylene glycol) gels containing highly concentrated sulfolane-based electrolytes exhibit high Li + transference numbers. The low polymer concentration and homogeneous polymer network in the gel electrolyte are useful in achieving both mechanical reliability and high Li + transport ability.

Electrolytes that transport only Li ions play a crucial role in improving rapid charge and discharge properties in Li secondary batteries. Single Li-ion conduction can be achieved via liquid materials such as Li ionic liquids containing Li + as the only cations because solvent-free fused Li salts do not polarise in electrochemical cells, owing to the absence of neutral solvents that allow polarisation in the salt concentration and the inevitably homogeneous density in the cells under anion-blocking conditions. However, we found that borate-based Li ionic liquids induce concentration polarisation in a Li/Li symmetric cell, which results in their transference (transport) numbers under anion-blocking conditions ( t abcLi) being well below unity. The electrochemical polarisation of the borate-based Li ionic liquids was attributed to an equilibrium shift caused by exchangeable B-O coordination bonds in the anions to generate Li salts and borate-ester solvents at the electrode/electrolyte interface. By comparing borate-based Li ionic liquids containing different ligands, the B-O bond strength and extent of ligand exchange were found to be directly linked to the t abcLi values. This study confirms that the presence of dynamic exchangeable bonds causes electrochemical polarisation and provides a reference for the rational molecular design of Li ionic liquids aimed at achieving single-ion conducting liquid electrolytes.

In Saccharomyces cerevisiae, class II gene promoters have been divided into two subclasses, TFIID- and SAGA-dominated promoters or TFIID-dependent and coactivator-redundant promoters, depending on the experimental methods used to measure mRNA levels. A prior study demonstrated that Spt3, a TBP-delivering subunit of SAGA, functionally regulates the PGK1 promoter via two mechanisms: by stimulating TATA box-dependent transcriptional activity and conferring Taf1/TFIID independence. However, only the former could be restored by plasmid-borne SPT3. In the present study, we sought to determine why ectopically expressed SPT3 is unable to restore Taf1/TFIID independence to the PGK1 promoter, identifying that this function was dependent on the construction protocol for the SPT3 taf1 strain. Specifically, simultaneous functional loss of Spt3 and Taf1 during strain construction was a prerequisite to render the PGK1 promoter Taf1/TFIID-dependent in this strain. Intriguingly, genetic approaches revealed that an as-yet unidentified trans-acting factor reprogrammed the transcriptional mode of the PGK1 promoter from the Taf1/TFIID-independent state to the Taf1/TFIID-dependent state. This factor was generated in the haploid SPT3 taf1 strain in an Hsp104-dependent manner and inherited meiotically in a non-Mendelian fashion. Furthermore, RNA-seq analyses demonstrated that this factor likely affects the transcription mode of not only the PGK1 promoter, but also of many other class II gene promoters. Collectively, these findings suggest that a prion or biomolecular condensate is generated in a Hsp104-dependent manner upon simultaneous functional loss of TFIID and SAGA, and could alter the roles of these transcription complexes on a wide variety of class II gene promoters without altering their primary sequences. Therefore, these findings could provide the first evidence that TFIID dependence of class II gene transcription can be altered epigenetically, at least in Saccharomyces cerevisiae., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Iwami et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)