Gadd45蛋白家族在肿瘤发生发展中的作用

Gadd45蛋白是一种响应环境的应激蛋白,在DNA修复、细胞周期调控及衰老、基因毒性应激反应等多种细胞功能中起着重要的调节作用,该类蛋白包括α,β和γ三种亚型。大量研究结果显示,它们在肿瘤细胞中参与了多种信号通路的调控,与肿瘤的发生及发展关系密切,其表达改变与肿瘤预后息息相关。本文就近年来Gadd45蛋白家族与肿瘤发生发展的研究进展进行简要介绍与阐述。

BOPPPS教学模式下的高校“遗传学”课程线上教学设计

2020年初由于新型冠状病毒的蔓延,全国各高校宣布延迟开学,开展网络课程。但缺少课堂教学,独立的线上教学面临学生难以进入学习状态、师生间缺乏及时互动、教学效果评价不够准确等问题。BOPPPS教学模式由bridge-in(导入)、objective(学习目标)、pre-assessment(前测)、participatory learning(互动教学)、post-assessment(后测)和summary(总结)6个环节构成。其导入、学习目标、前测环节有助于学生快速进入学习状态,师生间多步骤的交流可以增强互动,同时也丰富了教学评价方式。因此将其引入遗传学线上教学不失为一种解决问题的有益方法。本文以BOPPPS教学模式为指导,设计了"基因工程概论"的教学方案,细化了各个教学实施环节,讨论了实际应用中可能遇到的问题,以期为线上教学、网络课程的发展提供新的方向和思路。

Field girth weldability evaluation of X70 UOE pipeline

Based on API STD 1104-2005 and CSA Z662-2007, field girth welding tests and girth weldability evaluations were executed for three types of wall thickness X70 UOE pipeline, in which the most popular main line girth welding method, single-wire automatic gas metal arc welding （GMAW）, was used. The welding procedure specification was optimized to achieve a good quality and cold-crack-free girth weld joint without preheating or post-weld heat treatment. In addition ,porosities ,inclusions ,and incomplete fusion defects were avoided. The tensile strength,bending ,Vickers hardness,Charpy V-notch impact toughness, and crack tip opening displacement fracture toughness of the girth weld joint were evaluated, and the field girth weldability of Baosteel＇ s X70 UOE pipeline is joint exhibited good mechanical performance. Thus, the excellent for automatic GMAW.

Girth welding procedure and weldability evaluation of coal seam gas transmission UOE pipeline

According to the requirements of Queensland Gas Company Ltd. （QGC）, the operator of the Queensland Curtis LNG （QCLNG） pipeline project in Australia, girth welding experiments and weldability evaluations have been carded out for three X70 UOE pipes from Baosteel based on API 1104 standards. Shielded metal arc welding （SMAW） and gas- shielded flux-cored wire arc welding （FCAW-G） have been applied, and the girth weld joint quality and mechanical performance were evaluated. It was found that the field girth weldability of Baosteel＇ s XT0 UOE pipes was excellent under the conditions used here and satisfied the requirements of the QCLNG project for field girth welding construction. Furthermore,Baosteel has offered a solution to the QCLNG project for pipeline girth welding in which the girth welding joint design, selection of welding processes and consumables, welding procedures, techniques and joint inspections are included. Such research provides important guidance for the difficult tie-in welding applications for the construction of the QCLNG pipelines in the field.

Application of a sintered flux in UOE pipe manufacturing

Submerged arc welding is one of the main processes used in the manufacture of UOE welded pipes. It determines directly the quality of the pipes. In the submerged arc welding process, flux plays a very important role ;it not only affects the performance of the weld seam but also has a significant impact on the generation and prevention of weld defects. It is important to use a sintered flux for UOE pipe production. To meet the high-quality requirements on UOE welded pipes, the flux should be chosen such that it can resist high current and high speed, and help the weld achieve low H and O contents. At the same time, storage and management of a flux also require stringent monitoring. Domestic enterprises generally use sintered fluxes for the production of welded pipes.

Automatic girth welding and performance evaluation of the joints of hot-induction-bend and line pipes with different wall thickness

During the process of laying long-distance oil and gas transmission pipelines, the hot-induction-bend method is extensively used when the direction has to be changed. By considering the pipeline＇ s ongoing processing and loading states during service, the pipeline that is generally used exhibits thicker walls than those that are observed in the line pipe. As such, during pipeline construction, hot-induction-bend and line pipes with different wall thickness are girth-welded. The chemical composition of hot-induction-bend and line pipes differs, with the carbon content being particularly higher in the hot-induction-bend pipe;it also depicts a higher carbon equivalent, which makes it possible to modify the girth of the pipe. In this study, using Baosteel＇ s standard X70M UOE hot- induction-bend and line pipes, solid-wire automatic gas-metal-arc girth welding was performed and the performance of the girth-welded joint was evaluated. Furthermore,the weldability of the pipeline girth and the microstructure of the girth-welded joint were analyzed. The results reveal that Baosteel＇ s standard UOE hot-induction-bend and line pipes exhibit good girth weldability, and their technical quality can be guaranteed in case of consumer field- construction applications.

Preface

As the most important material joining technology in the manufacturing industry, welding has attracted extensive attention all along, and is called the dressmaker of the iron and steel industry. As the foundation for steel applications, welding technologies and procedures are directly related to the quality and level of manufacture, and furthermore to the function and safety of large equipment and projects. As soon as the Research Institute was constituted in Baosteel, a special welding research division was established with the support of the company. From then on, researches on welding technologies for new materials have been conducted, including welding procedure studies, welding consumable development and engineering application. Welding has become a strong support for new product development and market expansion. Through long-time efforts, Baosteel has kept ahead in China in the development of new welding consumables and new welding technologies matching with new kinds of steel for many fields, such as engineering machinery, pipeline, pressure vessels, railway vehicles and special manufacturing. The welding consumables and welding procedures developed by Baosteel have been widely used, part of which have been brought into industry standards. With the fast pace of new product development at Baosteel, especially the development of high-strength steel, extra-high-strength steel and high-alloy steel（e. g. new-type nickel-based alloy, etc. ）, great challenges have appeared in the welding technology field. Therefore, all of the welding technology researchers in Baosteel have been committed to such a mission： how to weld new kinds of steel, thereby offering integrated solutions to customers. Meanwhile, researches on customer application technologies should play an important role in the transformation of Baosteel from manufacturing to service. As Baosteel and the whole iron and steel industry are facing a rigorous situation, this welding technology special issue has been published in order to call attention of all welding technology researchers and thereby help achieve the strategic object of Baosteel to transform from manufacturing to service.