Influence of Annealing on Microstructure and Mechanical Properties of Refractory CoCrMoNbTi0.4 High-Entropy Alloy

Metallurgical and Materials Transactions A - A novel refractory CoCrMoNbTi0.4 high-entropy alloy (HEA) was prepared via vacuum arc melting. After annealing treatment at different temperatures, the...     

The planning of microdistricts in post-war North Korea: space,power, and everyday life

In the 1950s, the Soviet Union and other communist countries developed a unique method for allowing socialist ideology to manifest in urban spaces. The theory of the microdistrict was invented to establish self-contained urban units that included both housing and public amenities and resulted in a tremendous change in the planning of communist cities. Because microdistricts satisfied the communities’ social requirements and facilitated mass-produced urban housing, the North Korean regime enthusiastically appropriated the microdistrict concept to fit its own reality. This theory has been applied to the country’s urban projects since 1955, a time when the urban population grew rapidly and construction boomed. The design and construction of microdistricts reflected North Korea’s power relation and substantially impacted everyday life. Thus, to more thoroughly understand post-war North Korean society and its urban planning principles, the microdistrict theory should be carefully examined. In light of this historical background, this paper analyses urban projects that were designed based on this theory and explores the impact of the microdistrict theory on the structure of large cities in North Korea.     

Comparison of different phosphorus‐fertiliser matrices to induce the recovery of phosphorus‐deficient maize plants

BACKGROUND: Previous studies have demonstrated the capacity of a new type of mineral fertiliser, known as rhizosphere‐controlled fertiliser (RCF), to supply adequate nutrition to plants while minimising nutrient losses. This fertiliser family is based on the presence a phosphoric matrix composed of metal–humic–phosphates, soluble not in water but in the rhizospheric acids released by plant roots as an expression of nutritional needs, principally citric acid. The aim of this study is to investigate the capacity of the RCF matrix and other phosphorus‐containing products to induce the recovery of phosphorus‐deficient maize plants. RESULTS: The results showed that RCF‐based P fertilisers were able to facilitate plant recovery, measured by the dry root and shoot weights, to the same extent as a water‐soluble P fertiliser (monopotassium phosphate). This fact was well correlated to both the variation pattern of citric and trans‐aconitic acids in the shoot and roots during the treatment, and P shoot and root contents. Likewise the analysis of the variation of P concentration in the nutrient solution during the treatment indicates that plant recovery is associated with the capacity of the plant to mobilise P from the different fertiliser matrices studied. CONCLUSION: These results confirm the findings obtained in previous in vitro studies and indicate the suitability of RCF strategy for the preparation of mineral fertilisers with a nutrient release pattern more sensitive to plant nutritional needs. Copyright © 2009 Society of Chemical Industry     

含铬废革屑对水体中染料的吸附

研究了含铬废革屑对水体中染料的吸附特性。结果表明 :含铬废革屑对酸性染料和直接染料有较大的吸附量 ,但对碱性染料的吸附量却较低。在酸性嫩黄G的最适吸附pH值为 3 .0的条件下 ,酸性嫩黄G的平衡浓度为 82 9mg/L ,其平衡吸附量达到 2 3 4mg/g ;在直接红棕RN的最适吸附 pH值为 9.0的条件下 ,直接红棕RN的平衡浓度为 1 1 5 7mg/L时 ,其平衡吸附量达到 1 5 2mg/g。含铬废革屑对酸性嫩黄G的吸附平衡符合Langmuir方程 ,而对直接红棕RN的吸附平衡符合Freundlich方程。吸附动力学研究表明 :含铬废革屑对以上 2种染料的吸附 ,符合拟二级速度方程。     

Toxicological assessment of 3-monochloropropane-1,2-diol (3-MCPD) as a main contaminant of foodstuff in three different in vitro models: Involvement of oxidative stress and cell death signaling pathway

3-Monochloropropane-1,2-diol (3-MCPD) as a main source of food contamination has always been known as a carcinogenic agent. Kidney, liver, testis, and heart seem to be the main target organs for 3-MCPD. Because oxidative stress and mitochondrial dysfunction have been realized to be involved in 3-MCPD-induced cytotoxicity, the present study aimed to investigate the probable toxicity mechanisms of 3-MCPD in isolated mitochondria, HEK-293 cell line, and cell isolated from the rats’ liver and kidney through measuring multiparametric oxidative stress assay. Based on the data indicating no significant difference between 3-MCPD-treated groups and control group, metabolites of 3-MCPD have a key role in organ toxicity caused by them. To further investigating the suggested hypothesis, the effect of 3-MCPD toxicity on HEK-293 cell line was examined. Although the proliferation declined after exposure to a low dose of 3-MCPD (10 to 200 µM), controversial responses in higher concentration (2 to 10 mM) have led to studies on the effect of oxidative stress and cell death signaling on isolated kidney and liver cells. Treatment of the isolated kidney and liver cells with 3-MCPD resulted in an increase in the level of reactive oxygen species (ROS), the collapse of mitochondrial membrane potential (MMP), and activation of cell death signaling without creating any significant difference in the amount of reduced glutathione. In fact, 3-MCPD can disrupt the mitochondrial electron transfer in isolated cells, which is correlated with the impairment of mitochondrial oxidative phosphorylation system, the rise of ROS level, and the failure of MMP, leading to the release of cytochrome c from mitochondria to cytosol and finally the activation of cell death signaling.     

Short communication: Technological and seasonal variations of vitamin D and other nutritional components in donkey milk

Vitamin D is an essential nutrient that plays a crucial role in calcium homeostasis and bone metabolism and also acts as a hormone. Although several studies on the content of vitamin D in bovine milk have been conducted, little information is available regarding donkey milk. In the context of the nutritional assessment of donkey milk, the aim of this study was to assess the vitamin D content in donkey milk and its chemical profile, with particular reference to seasonal and technological modifications after pasteurization. The study was conducted on a dairy farm that produces donkey milk for human consumption located in central Italy. At sampling time, an aliquot of total bulk milk production was sampled before and after pasteurization (63°C for 30 min without homogenization) with a total of 20 raw and 20 pasteurized milk samples. The samples were collected for 10 mo, every 15 d, from May to February 2017. All the samples were analyzed for the chemical composition and vitamin D₂ and D₃ content by HPLC after saponification. The donkey milk analyzed showed a higher average vitamin D content (raw milk: vitamin D₂ = 1.68, vitamin D₃ = 0.60 μg/100 mL; pasteurized milk: vitamin D₂ = 1.38, vitamin D₃ = 0.30 μg/100 mL) than reported for bovine and human milk. The results of the effect of pasteurization on milk did not highlight significant differences in the total content of vitamin D. However, vitamin D₃ has a poor thermal stability, which led to a significant reduction in content in pasteurized milk compared with raw milk. The total vitamin D content of donkey milk did not show significant variations between seasons; however, a higher concentration of vitamin D₃ was found in spring and summer. In conclusion, raw and pasteurized donkey milk showed a high content of vitamin D, which could be useful in meeting the deficiencies of this vitamin in humans. Further investigations are needed to improve the vitamin D content in donkey milk by increasing its endogenous synthesis or its transfer in milk and to clarify other variability factors.     

Characterization of the rheological and mechanical properties of shear thickening fluid-coated Twaron® composite

The effects of the weight fraction (concentration) and silica particle size on steady and dynamic rheological responses of shear thickening fluids (STFs) and the quasi-static (QS) penetration resistance of Twaron®/STF composites have been investigated. The STFs have been made by mechanically dispersing 12 or 60 nm silica particles in polyethylene glycol with molecular weight of 400 gr/mol at three different concentrations. Rheological results indicate that with the increase in the concentration of silica in the STF, the critical shear rate (onset of shear thickening) diminish, the initial, critical, and ultimate viscosities increase and the slope of the shear thinning and shear thickening regions tend to be more steeper. Regarding STFs with larger particle sizes, critical shear rate, the initial, critical, and ultimate viscosities as well as the viscoelastic modules diminish. Addressing the Twaron®/STF composite, the increase in STF concentration and reduction in the silica particles size contribute to considerable increase in the puncture characteristics. The most noticeable puncture characteristics turn out in the case of 35 wt. % STF/Twaron® composites containing 12 nm particles in which the maximum bearable load and the maximum absorption energy are nearly 3.6 and 2.3 times larger than those of the neat Twaron®.