Ethylene and Nitric Oxide Involvement in the Regulation of Fe and P Deficiency Responses in Dicotyledonous Plants

Iron (Fe) and phosphorus (P) are two essential elements for plant growth. Both elements are abundant in soils but with poor availability for plants, which favor their acquisition by developing morphological and physiological responses in their roots. Although the regulation of the genes related to these responses is not totally known, ethylene (ET) and nitric oxide (NO) have been involved in the activation of both Fe-related and P-related genes. The common involvement of ET and NO suggests that they must act in conjunction with other specific signals, more closely related to each deficiency. Among the specific signals involved in the regulation of Fe- or P-related genes have been proposed Fe-peptides (or Fe ion itself) and microRNAs, like miR399 (P), moving through the phloem. These Fe- or P-related phloem signals could interact with ET/NO and confer specificity to the responses to each deficiency, avoiding the induction of the specific responses when ET/NO increase due to other nutrient deficiencies or stresses. Besides the specificity conferred by these signals, ET itself could confer specificity to the responses to Fe- or P-deficiency by acting through different signaling pathways in each case. Given the above considerations, there are preliminary results suggesting that ET could regulate different nutrient responses by acting both in conjunction with other signals and through different signaling pathways. Because of the close relationship among these two elements, a better knowledge of the physiological and molecular basis of their interaction is necessary to improve their nutrition and to avoid the problems associated with their misuse. As examples of this interaction, it is known that Fe chlorosis can be induced, under certain circumstances, by a P over- fertilization. On the other hand, Fe oxides can have a role in the immobilization of P in soils. Qualitative and quantitative assessment of the dynamic of known Fe- and P-related genes expression, selected ad hoc and involved in each of these deficiencies, would allow us to get a profound knowledge of the processes that regulate the responses to both deficiencies. The better knowledge of the regulation by ET of the responses to these deficiencies is necessary to properly understand the interactions between Fe and P. This will allow the obtention of more efficient varieties in the absorption of P and Fe, and the use of more rational management techniques for P and Fe fertilization. This will contribute to minimize the environmental impacts caused by the use of P and Fe fertilizers (Fe chelates) in agriculture and to adjust the costs for farmers, due to the high prices and/or scarcity of Fe and P fertilizers. This review aims to summarize the latest advances in the knowledge about Fe and P deficiency responses, analyzing the similarities and differences among them and considering the interactions among their main regulators, including some hormones (ethylene) and signaling substances (NO and GSNO) as well as other P- and Fe-related signals.     

液相法制备磷酸铁锂的研究进展

介绍了锂离子电池正极材料磷酸铁锂（LiFePO4）的晶体结构和充放电特性,评述了固相法和液相法制备LiFePO4。系统介绍了近几年液相法制备LiFePO4的研究进展,包括水热法,溶胶-凝胶法,共沉淀法等。并对LiFePO4正极材料的应用前景做了展望。     

Impact of precursor preparation on density of gadolinium iron garnets synthesized via reactive sintering

Gadolinium iron garnet was obtained from two different precursors, homogenized in isopropyl alcohol and in an aqueous environment with a fixed pH. In the first case, it was a mixture of goethite (FeO(OH)) and gadolinium oxide (Gd₂O₃); in the second, a mixture of GdIP (GdFeO₃) and α-Fe₂O₃. Conditions of homogenization in the aqueous environment were selected based on the zeta (ξ) potential measurements as the function of pH. DSC measurements of the output powder mixtures allowed the identification of the effects observed during the temperature rise. In the case of the material obtained from a mixture of goethite (FeO(OH)) and gadolinium oxide, with the increasing temperature, we observe three effects, the first of which corresponds to the phase transformation of goethite into α-Fe₂O₃, the second corresponds to the reaction of gadolinium iron perovskite (GdIP) formation, and the third to the reaction in which a gadolinium iron garnet (GdIG) is formed. However, in the case of heat treatment of the mixture of GdIP and α-Fe₂O₃, we only observe the effect responsible for a solid state reaction leading to the formation of gadolinium iron garnet. Dilatometric measurements allowed to determine the changes in linear dimensions at various stages of reaction sintering. The resulting materials were sintered at temperatures of 1200, 1300, and 1400 °C. In the case of the material obtained from a mixture of perovskite and iron (III) oxide, already at the temperature of 1300 °C, a density has been obtained at around 95% of the theoretical density, and the temperature of 1400 °C allowed achieving a density of 97% of the theoretical density. Whereas, for the material obtained from a mixture of goethite (FeO(OH)) and gadolinium oxide, a density above 95% of theoretical density was achieved only at 1400 °C.     

Leaching of iron concentrate separated from kiln slag in zinc hydrometallurgy with hydrochloric acid and its mechanism

It is taken as a novel prospective process to treat iron concentrate from hydrometallurgical zinc kiln slag for comprehensive utilization of valuable metals by a hydrochloric acid leaching-spray pyrolysis method. The leaching mechanism of different valuable metals was studied. The results revealed that the leaching rates of Ag, Pb, Cu, Fe, As and Zn were 99.91%, 99.25%, 95.12%, 90.15%, 87.58% and 58.15%, respectively with 6 mol/L HCl and L/S ratio of 10:1 at 60 °C for 120 min. The action of SiO₂ in leaching solution was also studied. The results showed that the precipitation and settlement of SiO₂(amorphous) adsorbed part of metal ions in solution, which greatly inhibited the leaching of Cu, Fe, As and Zn, so it is crucial to control the precipitation of amorphous SiO₂.     

Modelling and simulation of local mechanical properties of high silicon solution-strengthened ferritic compacted graphite iron

This study focuses on the modelling and simulation of local mechanical properties of compacted graphite iron cast at different section thicknesses and three different levels of silicon, ranging from about 3.6% up to 4.6%. The relationship between tensile properties and microstructure is investigated using microstructural analysis and statistical evaluation. Models are generated using response surface methodology, which reveal that silicon level and nodularity mainly affect tensile strength and 0.2% offset yield strength, while Young′s modulus is primarily affected by nodularity. Increase in Si content improves both the yield and tensile strength, while reduces elongation to failure. Furthermore, mechanical properties enhance substantially in thinner section due to the high nodularity. The obtained models have been implemented into a casting process simulation, which enables prediction of local mechanical properties of castings with complex geometries. Very good agreement is observed between the measured and predicted microstructures and mechanical properties, particularly for thinner sections.     

动力学分光光度法测定食品中的痕量铁

介绍了一种动力学分光光度测定痕量铁的方法。在ｐＨ＝４．７０的ＨＡｃＮａＡｃ介质中,Ｆｅ（Ⅲ）对Ｈ２Ｏ２氧化番红花Ｔ的反应具有强烈的催化作用,使溶液颜色褪去。该溶液最大吸收波长为５２０ｎｍ,铁含量在３．０８×１０６２．８０×１０５ｇ／Ｌ范围内遵从比尔定律,表观摩尔吸光系数为５．６×１０５Ｌ·ｍｏｌ１·ｃｍ１,回归方程为：ΔＡ＝５．６×１０５ＣＦｅ（Ⅲ）＋０．０２（Ｃ的单位为ｍｏｌ·Ｌ１）,相关系数γ＝０．９９９９,检出限为３．１６×１０６ｇ／Ｌ,同时也研究了多种干扰离子对测定的影响,该方法应用于测定食品如大米、面粉中的痕量铁取得了满意的结果     

Oxidation of polyvinyl alcohol by persulfate activated with heat,Fe, and zero-valent iron

The oxidation of polyvinyl alcohol (PVA) by persulfate (S₂O₈²⁻) activated with heat, Fe²⁺, and zero-valent iron (Fe(0)) was investigated via batch experiments. It was hypothesized that elevated temperature and the addition of Fe²⁺ or Fe(0) into a persulfate-water system could enhance the oxidation of PVA by activated persulfate. Increasing the temperature from 20 to 60 °C or 80 °C accelerated the oxidation rate of PVA, which achieved complete oxidation in 30 and 10 min, respectively. At 20 °C, the addition of Fe²⁺ or Fe(0) to the persulfate-water system significantly enhanced the oxidation of PVA. The optimal persulfate-to-Fe²⁺ or Fe(0) molar ratio was found to be 1:1. Complete oxidation of PVA was obtained by Fe(0)-activated persulfate in 2 h. Synergistic activation of persulfate by heat and Fe²⁺ or Fe(0) was also shown to enhance the oxidation of PVA in the persulfate-water system. By using GC–MS analysis, an oxidation product of PVA was identified as vinyl acetic acid (C₄H₆O₂), which is readily biodegradable. Our results suggest that the oxidative treatment of PVA by activated persulfate is a viable option for the pretreatment of PVA-laden wastewater to enhance its biodegradability.     

钢铁企业循环经济评价指标研究

如何客观地评价钢铁企业循环经济的发展状况是钢铁企业循环经济的一个关键性课题。采用综合评价法，从指标的选取，权重的确定到综合得分，分步阐述，构建一个完整、客观、实用的评价体系。     

Prevention of Internal Cracks in Forward Extrusion by Means of Counter Pressure: A Numerical Treatise

In the context of forward bulk extrusion, where product defects are frequently observed, the effect of counter pressure on damage accumulation materializing a Continuum Damage Mechanics (CDM) approach is presented. A Lemaitre variant damage model accounting for unilateral damage evolution coupled with a multiplicative finite plasticity is utilized for this purpose. After a presentation of the crack governing mechanism, it is demonstrated that application of counter pressure introduces a marked decrease in the central damage accumulation, which in turn increases the formability of the material through keeping the tensile triaxiality in tolerable limits. It is also shown that, for a crack involving process, through systematic increase of the counter pressure, the crack sizes diminish; and at a certain level of counter pressure chevron cracks can be completely avoided.     

As cast acicular ductile aluminum cast iron

 The effects of 2.2% Ni and 0.6% Mo additions on the kinetics, microstructure and mechanical properties of ductile aluminum cast iron were studied in the as-cast and tempered conditions. Test bars machined from cast to size samples, were used for mechanical and metallurgical studies. The results showed that the addition of Ni and Mo to the base iron produces an upper bainitic structure resulting in an increase in strength and hardness. The same trend was shown when the test bars tempered from 300oC in the range of 300 to 400oC. The elongation increased with increasing the temperature from 300 to 400oC. The carbon content of the retained austenite also increased with increasing temperature. The results also showed that the kinetics, microstructure and mechanical properties of this iron are similar to Ni-Mo alloyed silicon ductile iron.