Generalized Approach towards Secretion-Based Protein Production via Neutralization of Secretion-Preventing Cationic Substrate Residues

Many heterologous proteins can be secreted by bacterial ATP-binding cassette (ABC) transporters, provided that they are fused with the C-terminal signal sequence, but some proteins are not secretable even though they carry the right signal sequence. The invention of a method to secrete these non-secretable proteins would be valuable both for understanding the secretory physiology of ABC transporters and for industrial applications. Herein, we postulate that cationic “supercharged” regions within the target substrate protein block the secretion by ABC transporters. We also suggest that the secretion of such substrate proteins can be rescued by neutralizing those cationic supercharged regions via structure-preserving point mutageneses. Surface-protruding, non-structural cationic amino acids within the cationic supercharged regions were replaced by anionic or neutral hydrophilic amino acids, reducing the cationic charge density. The examples of rescued secretions we provide include the spike protein of SARS-CoV-2, glutathione-S-transferase, streptavidin, lipase, tyrosinase, cutinase, growth factors, etc. In summary, our study provides a method to predict the secretability and a tool to rescue the secretion by correcting the secretion-blocking regions, making a significant step in understanding the physiological properties of ABC transporter-dependent protein secretion and laying the foundation for the development of a secretion-based protein-producing platform.     

铌钒复合微合金化400MPa级钢筋的研制与生产

介绍了采用铌钒复合微合金化技术研制开发HRB400钢筋的工艺和产品性能,分析了冶炼、轧制工艺及合金元素对钢筋性能的影响规律,并应用回归分析方法确定了铌、钒元素对性能影响的经验公式,对开发铌钒微合金钢具有很好的指导意义。实践证明,采用铌钒复合技术生产HRB400钢筋,不仅其机械性能良好,而且具有低成本优势。     

ZLSG-400GD全自动排污滤水器在三峡地下电站中的应用

本文主要介绍了ZLSG-400GD全自动排污滤水器工作原理及其技术特点,以及滤水器在三峡电厂地下电站中的应用,并与三峡左岸、右岸ZLSG-400G型滤水器进行了对比分析。     

HRB400级钢筋钢丝网混凝土梁抗弯性能的试验研究

对 HRB400级钢筋钢丝网混凝土梁进行了正截面抗弯试验研究。试验包括6根在箍筋表面绑扎钢丝网的试件和2根未绑扎钢丝网的对比试件。试验的主要目的是研究采取该施工工艺后,钢丝网对裂缝间距和宽度的影响作用。试验中量测了受弯构件的开裂荷载、极限荷载、钢筋应变、混凝土应变以及跨中挠度。试验结果表明,箍筋表面的钢丝网可以明显地改善构件的抗裂性能,裂缝的间距和宽度明显减小。     

主机业务连续性方案设计

伴随着中国高速发展的经济形势,国内的金融行业竞争也愈来愈明显。这种竞争不光体现在服务内容的竞争,也体现在了服务质量的竞争,谁能为客户提供快捷、方便、稳定的金融服务就能在市场竞争中立于不败之地。计算机系统在金融行业的稳定持续运行,对于金融行业的业务连续性起着至关重要的作用。在努力提高单机的可靠性的同时,一旦故障或灾难发生,如何迅速恢复生产运行也同样至关重要。本文针对IBMAS/400基于OMS的各种业务连续性技术方案进行了探讨。     

Note To The Mixed-Type Splitting Iterative Method For The Positive Real Linear System

In [5] a new iterative method is given for the linear system of equations Au=b , where A is large, sparse and nonsymmetrical and A^{\rm T}+A is symmetric and positive definite (SPD) or equivalently A is positive real. The new iterative method is based on a mixed-type splitting of the matrix A and is called the mixed-type splitting iterative method. The iterative method contains an auxiliary matrix D_1 that is restricted to be symmetric. In this note, the auxiliary matrix is allowed to be more general and it is shown that by proper choice of D 1 , the new iterative method is still convergent. It is also shown that by special choice of D_{1} , the new iterative method becomes the well-known (point) accelerated overrelaxation (AOR) [1] method. Hence, it is shown that the (point) AOR method applied to the positive real system is convergent under the proper choice of the overrelaxation parameters y and .     

A bill of materials-based approach for end-of-life decision making in design for the environment

Re-use, recycling or remanufacturing of products and components are good alternatives for reducing the environmental problems resulting from the huge amounts of waste currently arriving at landfills. A new approach is proposed in this paper for enhancing these alternatives from the earliest stages of product design. Given the product structure (obtained from its bill of materials (BOM)) and the joining and geometrical relationships among the components (obtained from the three-dimensional, computer-aided design representation), a model is proposed that will determine the EOL (EOL) strategy, i.e. the depth of disassembly inside the structure and the final end (re-use, recycle, remanufacture or disposal) for each disassembled part leading to the highest profit. A scatter search (SS) metaheuristic is used to determine the disassembly cost at each level of the BOM. The model presents a number of major improvements with respect to previous research. It addresses the problems of simultaneously determining both the best EOL strategy and the disassembly sequence, as well as allowing removal of components not only over the two or three Cartesian axes and affording the possibility of modifying the encountered strategy in a further step so as to fulfil other business criteria (such as disassembly time, resources availability or maximum waste generation rate).     

Characterization of stainless steel parts by Laser Metal Deposition Shaping

Laser Metal Deposition Shaping (LMDS) is a new rapid manufacturing technology, which can build fully-dense metal components directly from the information transferred from a computer file by depositing metal powders layer by layer with neither mould nor tool. Typically, performed with stainless steel (SS) 316 powder, the orthogonal experiments combining with the ideal overlapping model were applied to ascertain the optimal processing parameters. Then the characteristics of microstructure, composition and phase of as-deposited cladding layers were analyzed through Scanning Electron Microscope (SEM) and X-ray diffraction (XRD), as well as relative model. Furthermore, the cooling rate and the solidification velocity during LMDS were evaluated based on empirical method. With the optimal parameters, some parts were fabricated without obvious defects, and then the mechanical properties of them were tested. Finally, the influencing regularities of critical parameters on microstructure and properties were concluded by comparison. The results prove that the microstructure of SS 316 deposits is composed of the slender dendrites growing epitaxially from the substrate, the mechanical properties are favorable and anisotropic, and the composition is uniform. Besides, the microstructure morphology and the mechanical properties are affected by the varied processing parameters at different degrees. Among them, the scanning speed shows the most remarkable effects on microstructure morphology, characteristic microscale, mechanical properties, as well as geometric shape of as-deposited parts.     

汉语谐音与语义双关语的认知神经加工差异——ERP证据

该文运用事件相关电位技术,观测汉语谐音双关语与语义双关语两者是否存在认知神经加工上的差异。结果发现,语义双关语的正确率明显低于谐音双关语以及不符合逻辑语篇的正确率。谐音双关语组、语义双关语组和不合逻辑语篇引发的脑电波数据在300～900ms之间存在显著差异。其中,语义双关语和不合逻辑语篇都引发了N400效应。脑电波形图和脑电波地形图显示,前者引发的N400效应略微晚于后者引发的N400效应,但数据统计的结果不显著。在600～900ms,谐音双关语引发了P600效应。研究由此推论: 汉语谐音双关语与语义双关语认知层面的加工差异与双关语的呈现形式和表达效果密切相关。     

Remediation of acid mine drainage using metallurgical slags

In this study basic oxygen and stainless steel slag were both assessed for potential use in treating acid mine drainage. The stainless steel slag was able to effect some pH change but was found to not be suitable. Basic oxygen slag was found to have a significant potential as a remediating agent. For a model acid mine water with a pH of 2.5, sulfate concentration of 5000 mg/L and iron concentration of 1000 mg/L, the slag was able to increase pH to 12.1, reduce the soluble iron by 99.7% and reduce sulfate by 75% in batch experiments. In these batch reactors most reaction was completed within 30 min indicating that this is a rapid process. Additional experiments were conducted with continuous flow reactors to assess the maximum treatment capacity of the slag. These experiments indicated that slag replacement strategies are wholly dependent on the strength of the acid mine drainage, the required residence time and the specified residual concentrations of iron or sulfate and the pH. The data indicate that in particular, basic oxygen furnace slag has significant potential as a replacement reagent for lime in treating acid mine drainage.