On Iron Metabolism and Its Regulation

Iron is a critical metal for several vital biological processes. Most of the body’s iron is bound to hemoglobin in erythrocytes. Iron from senescent red blood cells is recycled by macrophages in the spleen, liver and bone marrow. Dietary iron is taken up by the divalent metal transporter 1 (DMT1) in enterocytes and transported to portal blood via ferroportin (FPN), where it is bound to transferrin and taken up by hepatocytes, macrophages and bone marrow cells via transferrin receptor 1 (TfR1). While most of the physiologically active iron is bound hemoglobin, the major storage of most iron occurs in the liver in a ferritin-bound fashion. In response to an increased iron load, hepatocytes secrete the peptide hormone hepcidin, which binds to and induces internalization and degradation of the iron transporter FPN, thus controlling the amount of iron released from the cells into the blood. This review summarizes the key mechanisms and players involved in cellular and systemic iron regulation.     

Interplay between Coumarin Accumulation,Iron Deficiency and Plant Resistance to Dickeya spp.

Coumarins belong to a group of secondary metabolites well known for their high biological activities including antibacterial and antifungal properties. Recently, an important role of coumarins in plant resistance to pathogens and their release into the rhizosphere upon pathogen infection was discovered. It is also well documented that coumarins play a crucial role in the Arabidopsis thaliana growth under Fe-limited conditions. However, the mechanisms underlying interplay between plant resistance, accumulation of coumarins and Fe status, remain largely unknown. In this work, we investigated the effect of both mentioned factors on the disease severity using the model system of Arabidopsis/Dickeya spp. molecular interactions. We evaluated the disease symptoms in Arabidopsis plants, wild-type Col-0 and its mutants defective in coumarin accumulation, grown in hydroponic cultures with contrasting Fe regimes and in soil mixes. Under all tested conditions, Arabidopsis plants inoculated with Dickeya solani IFB0099 strain developed more severe disease symptoms compared to lines inoculated with Dickeya dadantii 3937. We also showed that the expression of genes encoding plant stress markers were strongly affected by D. solani IFB0099 infection. Interestingly, the response of plants to D. dadantii 3937 infection was genotype-dependent in Fe-deficient hydroponic solution.     

Preparation of Iron Filler-Based Photocomposites and Application in 3D Printing

The introduction of metallic fillers to polymers via the photopolymerization approach can endow the composite materials with some unique properties, but the relevant research is still scarce due to the issue of light penetration and inner filter effect. Herein, for the first time the fabrication of photocomposites based on fine iron powder (i.e., a typical kind of metallic filler) is reported in this work. The free radical polymerization of two different acrylate monomers, poly(ethylene glycol) diacrylate and trimethylolpropane triacrylate, is performed in the presence of iron filler under mild conditions (i.e., light emitting diode (LED)@405 nm irradiation at room temperature under air). And the real-time Fourier transform infrared spectroscopy reveals remarkable photopolymerization kinetics of acrylates with high final conversions and fast polymerization rates despite the increasing contents of iron filler in the composites. Interestingly, the 3D printing technique is applied to the iron filler-based composites to produce tridimensional patterns with excellent spatial resolution. This work not only paves the way for the investigation of photocomposites based on metallic fillers through photochemical methods, but also broadens the potential application prospects.     

常规两段浸出法提高锌焙烧矿中铜回收率的研究

分析了不同湿法炼锌工艺锌焙烧矿中回收铜的工艺,发现各工艺都存在不同的工艺缺点。借鉴国内锌冶炼企业开展的常规两段浸出法提高铜回收率的生产经验,进行了锌焙烧矿中铜、铁、硅的浸出机理研究,并且根据该机理提出了常规两段浸出法的改进工艺流程,按照该工艺流程开展了试验研究,将铜的回收率提高到了76.41%。     

机械活化条件下超细铁矿粉氢基还原特性及机制

摘要：通过热重法研究了不同机械活化程度的铁矿粉氢基还原特性,并分析和探讨了其还原反应机制。实验结果表明,机械活化对氢气还原铁矿粉有促进作用,机械活化时间越长,还原特征温度越低,还原反应所需的活化能也越低,但反应机制未发生变化,反应的限制性环节是其界面反应。机械活化明显影响到超细铁矿粉的逐级反应,对于未经活化的铁矿粉而言,逐级反应层次极不明显,而对于活化后铁矿粉的逐级反应层次随着活化时间的增加越发分明。     

低锰高铁矿直接还原-熔分制备富锰渣试验研究

摘要：试验以锰品位27.7%,铁品位18.1%的低锰高铁矿为研究对象还原制备富锰渣,生产得到的富锰渣可用于冶炼硅锰合金,以达到高效利用低品位锰矿的目的。根据该矿的成分分析、XRD分析和粒度检测分析结果,采用还原 熔分法对低锰矿进行还原制备富锰渣试验,试验结果表明：单因素试验下各参数对低锰高铁矿的还原-熔分后渣中Mn、Fe元素的含量和Mn元素的回收率均有较大影响,同时结合Box-Behnke原理设计方案,选取温度、碱度以及配碳量3个试验因素,通过响应曲面法研究各因素交互作用下对Mn元素回收率的影响规律,对试验因素进行优化分析,建立相应的多项式模型。模拟优化得到最优的工艺条件为：还原温度1402℃,碱度0.10,配碳量10.04%,Mn元素回收率为97%。在最佳条件下做验证试验得出Mn元素回收率为95.80%,误差1.24%,证明响应曲面法预测模型具有可靠性,同时对低锰高铁矿的应用有重要指导意义。     

合金元素P,Cu含量对铸铁短纤维结合剂组织和性能的影响

本文研究了合金元素磷和铜对铸铁短纤维烧结体显微组织和性能的影响。结果表明，合金元素磷可显著提高铸铁短纤维烧结体的密度、致密化系数和压强度。磷与铜的共同加入可进一步提高烧结体的压溃强度和硬度，同时，铜的加入可抑制由磷引起的烧结体的急剧。烧结机理随磷、铜含量的增加逐渐由固相烧结＋瞬态液烧结转变为液相烧结。     

Use of electron microscopy on microstructure characterization of high chromium cast irons

The physical metallurgy underlying the development of cast microstructures in abrasion resistant high chromium cast irons, and their structural modification by thermal treatments is relatively complex. Structural characterisation via electron microscopy therefore has a key role to play in furthering our understanding of the phase transformations that control the microstructures and hence the service performances of these irons as wear parts. This paper shows how both scanning and especially transmission electron microscopy can provide valuable information on the nature of eutectic and secondary carbides and on the matrix structures in these irons. Particular attention is given to current characterisation research on conventionally cast 30%Cr irons that are used for applications involving corrosive wear e.g. slurry pumps and on a semi-solid cast 27%Cr iron that has a potential for applications in industry.     

扫描速度对硼铸铁气缸套表面钨极氩弧硬化效果的影响

研究了钨极氩弧扫描速度对硼铸铁表面硬化效果的影响规律。结果表明：扫描速度增加,硬化层宽度、深度减小,而硬度提高,裂纹率增大；硬化层硬度沿层深的分布是从表及里由高而低,在过渡区下降缓慢；沿层宽的分布是层中心最高,向两侧逐渐降低,直至硼铸铁基体达到最低值；在保证不出现裂纹的条件下,硬化层表面的最高硬度值可达61．4HRC,硬化层最高显微硬度值可达1156．4HV0．1；硼铸铁材料采用氩弧热源淬火时,淬硬层与基体之间过渡区明显,硬化区组织为莱氏体,过渡区为马氏体、残余奥氏体和少量石墨。