Effect of microwave heating time on the gel properties of chicken myofibrillar proteins and their formation mechanism

The present work was conducted to illustrate the mechanism of gel formation of myofibrillar proteins (MPs) under different microwave heating times. The results showed that the denaturation enthalpy (ΔH) of the MPs significantly decreased when the heating time increased from 3 to 9 s and then completely disappeared as the heating time progressed, indicating that the MPs gradually denatured and subsequently aggregated with increasing heating time, which was further verified by the changes in the secondary structure, electrophoretic bands, and gel properties (e.g., water holding capacity and textural profiles) of the MPs. Microstructural images indicated that the MP gel formed under 12 s had the most compact network, indicating that extended microwave heating time could induce quality deterioration of MP gels. Moreover, the hydrophobic forces, electrostatic forces, and disulphide bonds of the MPs gradually intensified with increasing microwave heating time, suggesting that both non-covalent and covalent bonds could promote molecular denaturation and subsequent aggregation of MPs. In addition, correlation analysis revealed that the changes in the molecular conformation of MPs induced by different microwave heating times could effectively regulate the formation of MP gels and their related properties.     

泸县6.0级地震文化遗产震害调查与分析

2021年9月16日，四川省泸县发生6.0级地震，对当地的文化遗产造成了不同程度的损坏。为掌握文化遗产在此次地震中的破坏情况，对古建筑、古桥、渡槽、摩崖造像、古遗址以及可移动文物进行震害调查，分析破坏原因，提出不同文化遗产的震害等级，并统计其在此次地震中破坏占比。研究结果表明：古建筑中木结构的震害较轻，砖木结构和石木结构的损伤较为严重，表现为墙体开裂、倾斜、倒塌和屋面损毁等破坏；古桥的桥面板产生裂缝和起壳，桥头堡基石发生移位；摩崖造像发生开裂、石像脱落，部分岩石发生坠落；古遗址的原有缝隙增大，石砌墙歪闪或倾斜；可移动文物与陈列台连接的金属卡件在地震下崩落。根据震害调查结果，将文化遗产的震害划分为4个等级，并对古建筑的维修与加固、摩崖造像的一体化监测、古桥的维护与应急抢险、可移动文物的隔震保护提出几点建议，为我国文化遗产的抗震保护提供参考。     

Cloning,sequencing and structural analysis of membrane-bound polyphenol oxidase from Granny Smith apples (Malus × domestica Borkh)

The gene sequence coding for the membrane-bound polyphenol oxidase (mPPO) with a length of 1761 bp was cloned by PCR method and shown to contain one highly conserved sequence encoding a di-copper-binding region. The predicted three-dimensional structure of mPPO indicated that the active site was located near two copper ions and composed of a typical bundle of four α-helices. Each of the two catalytic copper ions was coordinated with three histidine residues in the hydrophobic pocket, yielding His 180, His 201, His 210, His 332, His 336 and His 366. Docking studies showed that 4-methylcatechol and chlorogenic acid have different binding models due to different ligand sizes and binding sites in the active centre, and it was found that the smaller compound exhibited a higher affinity for mPPO. Molecular dynamic simulation results indicated that Phe 353 is important in controlling enzymatic activity through influencing substrate coordination in the active site.     

Reaction Mechanism of Lithium-Ion Battery Fire Extinguishing Agent-Perfluorinated Hexanone Oxidizes Metal-Al

Fire Technology - The use of perfluorinated hexanone as a fire extinguishing agent for lithium-ion batteries (LIBs) has been steadily increasing in China in recent years. It successfully handles...     

Special Issue on Artificial Intelligence and Technology: Trend,Challenges, and Opportunities

Mobile Networks and Applications -     

Fabrication of high-efficiency Yb:Y2O3 laser ceramics without photodarkening

High-efficiency Yb:Y₂O₃ laser ceramics were fabricated using the vacuum-sintering plus hot isostatic pressing (HIP) without sintering additives. High-purity well-dispersed nanocrystalline Yb:Y₂O₃ powder was synthesized using a modified co-precipitation method in-house. The green bodies were first vacuum sintered at a temperature as low as 1430°C and then HIPed at 1450°C. Finally, the samples were air annealed at 800°C for 10 h. Although no sintering aids were used, full density of the samples with excellent optical homogeneity and an inline transmission of 80% at 400 nm could be obtained. Moreover, photodarkening phenomenon was not detected in the ceramics. Preliminary laser experiment with the fabricated ceramics in a two-mirror cavity has demonstrated 32 W continuous-wave (CW) output at ∼1077 nm with an optical-to-optical conversion efficiency of 58.2%. To the best of our knowledge, this is so far the highest CW output power and optical-to-optical conversion efficiency achieved with the Yb³⁺-doped sesquioxide ceramics in a simple two-mirror cavity.     

Improved thermal stability of the near-infrared Al-modulated Zn3Ga2GeO8: Cr3+ phosphors for plant growth applications

The exploration of the high thermal stability near-infrared (NIR) phosphors is significantly crucial for the development of plant lighting. However, NIR phosphors suffer from the poor chemical and thermal stability, which severely limits their long-term operation. Here, the successful improvement of luminous intensity (149.5%) and thermal stability at 423 K of Zn₃Ga₂GeO₈ (ZGGO): Cr³⁺ phosphors is achieved for the introduction of Al³⁺ ions into the host. The release of carriers in deep traps inhibits the emission loss for the thermal disturbance. Furthermore, an NIR light emitting diodes (LEDs) lamp is explored by combining the optimized Zn₃Ga_1.1675Al_0.8GeO₈: 0.0325Cr³⁺ phosphors with a commercial 460 nm blue chip, and the emission band can match well with the absorption bands of photosynthetic pigments and the phytochrome (P_R and P_FR) of plants. The explored LEDs lamp further determines the growth and the pheromone content of the involved plants for the participation of the NIR emission originated from Cr³⁺ ions. Our work provides a promising NIR lamp as plant light with improved thermal stability for long-term operation.     

GM-CSF及CBS在肝损伤中的研究进展

肝损伤(liver injury)是指基因遗传或外部原因诱发的肝脏功能异常性疾病.临床表现为食欲不振、乏力、恶心、黄疸、疲乏等,严重者将出现肝功能衰竭,致死风险极高.在交通肇事、暴力犯罪及意外事件中,肝由于体积大、位置固定、质地脆弱、血运丰富等原因,往往是最容易发生损伤的器官之一,肝损伤后的死亡率可高达10.5％～25％[1].随着时间的变化,肝损伤的程度、病理改变、GM-CSF等相关细胞因子及CBS等相关酶的表达水平也会进一步变化.肝损伤后,由于肝内部环境稳态的破坏,器官的状态、结构、各种蛋白的转录水平、蛋白及细胞因子的表达变化水平也会发生一定程度的改变.因此定性定量地分析这些变化,找到时间相关性强的特异性指标,对于指导法医学的实践具有重要的作用.因此在法医学鉴定中,通过肝脏损伤及病变程度的改变,明确肝损伤病变与死亡时间的关系有利于判断事件或案件性质,并有助于进一步对责任方的认定.     

NeuCrowd: neural sampling network for representation learning with crowdsourced labels

Knowledge and Information Systems - Representation learning approaches require a massive amount of discriminative training data, which is unavailable in many scenarios, such as healthcare, smart...