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Abstract The main protease (Mpro) of SARS-CoV-2 is critical for viral function and a key drug target. Mpro is only active when reduced; turnover ceases upon oxidation but is restored by re-reduction. This suggests the system has evolved to survive periods in an oxidative environment, but the mechanism of this protection has not been confirmed. Here, we report a crystal structure of oxidized Mpro showing a disulfide bond between the active site cysteine, C145, and a distal cysteine, C117. Previous work proposed this disulfide provides the mechanism of protection from irreversible oxidation. Mpro forms an obligate homodimer, and the C117-C145 structure shows disruption of interactions bridging the dimer interface, implying a correlation between oxidation and dimerization. We confirm dimer stability is weakened in solution upon oxidation. Finally, we observe the protein’s crystallization behavior is linked to its redox state. Oxidized Mpro spontaneously forms a distinct, more loosely packed lattice. Seeding with crystals of this lattice yields a structure with an oxidation pattern incorporating one cysteine-lysine-cysteine (SONOS) and two lysine-cysteine (NOS) bridges. These structures further our understanding of the oxidative regulation of Mpro and the crystallization conditions necessary to study this structurally.

为探究云南引种美国山核桃品种之间的品质差异，为其深加工和品种选育奠定理论基础，选择9个有代表性的美国山核桃品种，测定其种仁的粗蛋白质、粗脂肪、维生素E、微量元素含量和脂肪酸组成，并对各指标进行相关性分析。结果表明：9个品种的美国山核桃种仁粗蛋白质含量在437~7.96 g/100 g之间，平均值为5.88 g/100 g；粗脂肪含量在53.21%~74.91%之间，平均值为65.90%；维生素E含量在0.89~1.22 mg/g之间，平均值为1.04 mg/g；9个品种美国山核桃种仁Zn、Fe、Ca含量平均值分别为0.068、0.118、0.514 mg/g，Pb含量平均值为0.115 μg/g，低于国标限值；9个品种美国山核桃种仁脂肪酸组成基本一致，主要为油酸、亚油酸、棕榈酸、硬脂酸、亚麻酸等；相关性分析表明各指标间均存在不同程度的正相关或负相关。不同品种美国山核桃在基本营养成分、脂肪酸组成及微量元素含量方面各有侧重，在精深加工过程中需要根据成品、配料、加工工艺等有针对性地选择，在品种培育方面，也可以根据各品种特点进行定向培养。In order to explore the quality differences among the main varieties of Carya illinoinensis introduced in Yunnan, and lay a theoretical foundation for their further processing and variety breeding, 9 representative varieties of Carya illinoinensis were selected, and the contents of crude protein, crude fat, vitamin E, microelements and fatty acid composition of the kernel were determined, and correlation analysis on various indicators was conducted. The results showed that the crude protein content of 9 varieties of Carya illinoinensis was 4.37-7.96 g/100 g, with an average value of 5.88 g/100 g; the crude fat content was 53.21%-74.91%, with an average value of 65.90%; the content of vitamin E was 089-1.22 mg/g, with an average value of 1.04 mg/g. The average values of Zn, Fe and Ca contents were 0.068, 0.118 mg/g and 0.514 mg/g, respectively; the average value of Pb content was 0.115 μg/g, lower than the national standard limit value. The fatty acids composition of 9 varieties of Carya illinoinensis was basically the same, and the order of their contents was oleic acid, linoleic acid, palmitic acid, stearic acid, linolenic acid, etc. Correlation analysis showed that there was varying degrees of positive or negative correlation between various indicators. Different varieties of Carya illinoinensis have their own emphasis on basic nutritional composition，fatty acid composition, and microelements content. In the process of deep processing of Carya illinoinensis, targeted selection of different varieties is required based on the finished product, ingredients, processing technology, etc. In terms of variety cultivation, targeted cultivation can also be carried out based on the characteristics of each variety.

Abstract Background The prognostic value of triglyceride-glucose (TyG) index in general type 2 diabetes mellitus (T2DM) patients is still unclear. Therefore, we aimed to determine the associations between TyG and all-cause/cause-specific death in a T2DM cohort and explore whether such associations would be modified by age. Methods A total of 3,376 patients with T2DM from the National Health and Nutrition Examination Survey (NHANES) 1999–2018 were selected and divided into the younger group (

Implantable collamer lens(ICL)and toric ICL(TICL)are clinically common types of posterior chamber phakic intraocular lenses, they are mainly used to correct high myopia and low-to-moderate myopia of eyes whose corneal conditions are not suitable for corneal laser surgery. Accurate preoperative measurement, safe intraoperative implantation and appropriate postoperative location of lenses are critical to ensure the outcome of ICL implantable, and the appearance of V4c ICL with a central hole ensures the safety of this surgery to a greater extent. However, the intraocular position of both ICL and TICL is not invariable. Some studies have shown that the vault has a trend of decreasing year by year after ICL surgery, but its reason is unknown. And spontaneous rotation may occur after the TICL surgery, thereby causing visual loss, which is one of the main causes of TICL replacement. And postoperative changes in the position of the central hole also need attention. In addition, the visual quality of the operated eye will change after ICL/TICL implantation, but whether the change of intraocular positions of implanted lenses will affect the postoperative visual quality is also a problem that needs to be paid attention to and explored. Therefore, this paper reviewed the postoperative changes in vault, TICL axis, position of the central hole and their causes, as well as the effects of these changes on postoperative visual quality, offering valuable clinical guidance for accurate preoperative selection of ICL/TICL and surgical design, so as to improve the effectiveness and stability of ICL implantation in correction of myopic refractive error.