VDACs Post-Translational Modifications Discovery by Mass Spectrometry: Impact on Their Hub Function

VDAC (voltage-dependent anion selective channel) proteins, also known as mitochondrial porins, are the most abundant proteins of the outer mitochondrial membrane (OMM), where they play a vital role in various cellular processes, in the regulation of metabolism, and in survival pathways. There is increasing consensus about their function as a cellular hub, connecting bioenergetics functions to the rest of the cell. The structural characterization of VDACs presents challenging issues due to their very high hydrophobicity, low solubility, the difficulty to separate them from other mitochondrial proteins of similar hydrophobicity and the practical impossibility to isolate each single isoform. Consequently, it is necessary to analyze them as components of a relatively complex mixture. Due to the experimental difficulties in their structural characterization, post-translational modifications (PTMs) of VDAC proteins represent a little explored field. Only in recent years, the increasing number of tools aimed at identifying and quantifying PTMs has allowed to increase our knowledge in this field and in the mechanisms that regulate functions and interactions of mitochondrial porins. In particular, the development of nano-reversed phase ultra-high performance liquid chromatography (nanoRP-UHPLC) and ultra-sensitive high-resolution mass spectrometry (HRMS) methods has played a key role in this field. The findings obtained on VDAC PTMs using such methodologies, which permitted an in-depth characterization of these very hydrophobic trans-membrane pore proteins, are summarized in this review.     

Ausmelt吹炼炉泡沫渣发生的成因与对策

通过Ausmelt吹炼炉的反应机理分析了Ausmelt吹炼炉发生泡沫渣的成因,并针对制约气体逸出速度和烟气生成速度过快的原因提出了相应的对策。     

转炉钢水过氧化原因分析及危害

莱钢120t氧气顶底复吹转炉存在钢水过氧化、终点[C]命中率低等问题,钢水过氧化导致炉渣黏度降低,不利于溅渣护炉,钢坯夹杂物增多,影响铸坯质量,增加钢铁料消耗和冶炼成本。导致钢水过氧化的原因主要是原材料条件差,操作不当,生产组织不协调以及铁水资源不足、废钢用量大等工艺制度的局限。     

The Effects of Moisture in Low‐Voltage Organic Field‐Effect Transistors Gated with a Hydrous Solid Electrolyte

The concept of using ion conducting membranes (50–150 μm thick) for gating low‐voltage (1 V) organic field‐effect transistors (OFETs) is attractive due to its low‐cost and large‐area manufacturing capabilities. Furthermore, the membranes can be tailor‐made to be ion conducting in any desired way or pattern. For the electrolyte gated OFETs in general, the key to low‐voltage operation is the electrolyte “insulator” (the membrane) that provides a high effective capacitance due to ionic polarization within the insulator. Hydrous ion conducting membranes are easy to process and readily available. However, the role of the water in combination with the polymeric semiconductor has not yet been fully clarified. In this work electrical and optical techniques are utilized to carefully monitor the electrolyte/semiconductor interface in an ion conducting membrane based OFET. The main findings are that 1) moisture plays a major part in the transistor operation and careful control of both the ambient atmosphere and the potential differences between the electrodes are required for stable and consistent device behavior, 2) the obtained maximum effective capacitance (5 μF cm^?2) of the membrane suggests that the electric double layer is distributed over a broad region within the polyelectrolyte, and 3) electromodulation spectroscopy combined with current–voltage characteristics provide a method to determine the threshold gate voltage from an electrostatic field‐effect doping to a region of (irreversible) electrochemical perturbation of the polymeric semiconductor.     

钢水过氧化原因分析及危害

从溅渣护炉操作、产品质量、冶炼成本三方面阐述了钢水过氧化现象带来的危害，并就造成过氧化现象的原因进行了较为系统的分析，指出原材料供给、生产组织、工艺路线及工艺制度存在的局限性，提出了相应看法和改进措施。     

Tuning Oxygen Redox Chemistry in Li‐Rich Mn‐Based Layered Oxide Cathodes by Modulating Cation Arrangement

Li‐rich Mn‐based oxides (LRMO) are promising cathode materials to build next‐generation lithium‐ion batteries with high energy density exceeding 400 W h kg^?1. However, due to a lack of in‐depth understanding of oxygen redox chemistry in LRMO, voltage decay is not resolved thoroughly. Here, it is demonstrated that the oxygen redox chemistry could be tuned by modulating cation arrangement. It declares that the materials with Li/Ni disorder and Li vacancies can inhibit the formation of O? O dimers. Because of the high chemical activity, O? O dimers could accelerate lattice oxygen release and NiO/spinel formation. The samples without forming O? O dimers show improved performance in suppressing oxygen overoxidation and mitigating cation dissolution. As a result, the optimized cathode exhibits a high capacity over 280 mA h g^?1 at 0.1 C and a high plateau voltage of 3.58 V with a very low voltage decay of 1.6% after 150 cycles at 1 C. This study opens an attractive path in designing Li‐rich electrodes with stabilized redox chemistry.