Development of phosphate rock integrated with iron amendment for simultaneous immobilization of Zn and Cr(VI) in an electroplating contaminated soil

Publication date: September 2017
Source:Chemosphere, Volume 182
Author(s): Ling Zhao, Zhenliang Ding, Jingke Sima, Xiaoyun Xu, Xinde Cao
This study aims to develop an amendment for simultaneous immobilization of Zn and Cr(VI) in an abandoned electroplating contaminated soil. Nature phosphate rock was first activated with oxalic acid (O-PR) and then combined with FeSO4 or zero-valent iron (ZVI) for immobilization of Zn and Cr(VI) from aqueous solutions. Finally, the optimized approach showing the highest immobilization ability in solution was applied in an electroplating contaminated soil. The O-PR combined with FeSO4 was more effective in simultaneously removing Zn and Cr(VI) than the O-PR integrated with ZVI within the tested solution pH range of 5.5–8.5. Both O-PR with FeSO4 and with ZVI removed over 95% of Zn from the solution; however, only 42–46% of Cr(VI) was immobilized by O-PR with ZVI, while O-PR with FeSO4 almost precipitated all Cr(VI). Moreover, there were 75–95% Zn and 95–100% Cr(VI) remaining in the exhausted O-PR with FeSO4 solid after toxicity characteristic leaching test (TCLP) while the exhausted O-PR with ZVI solid only retained 44–83% Zn and 32–72% Cr(VI). Zinc was immobilized mainly via formation of insoluble Fe-Zn phosphate co-precipitates, while iron-induced reduction of Cr(VI) into stable Cr(OH)3 or CrxFe(1-x)(OH)3 was responsible for Cr(VI) immobilization. Application of the O-PR integrated with FeSO4 in the electroplating contaminated soil rapidly reduced the TCLP extractable Zn and Cr(VI) to below the standard limits, with decrease by 50% and 94%, respectively. This study revealed that combination of oxalic acid activated phosphate rock with FeSO4 could be an effective amendment for remediation of Zn and Cr(VI) contaminated soil.

Graphical abstract

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Effects of reheating and subsequent rapid cooling on microstructural evolution and semisolid forming behaviors of extruded Mg–8.20Gd–4.48Y–3.34Zn–0.36Zr alloy

Publication date: September 2017
Source:Journal of Materials Processing Technology, Volume 247
Author(s): Yi Meng, Qiang Chen, Sumio Sugiyama, Jun Yanagimoto
Reheating and rapid cooling experiments, and semisolid compression tests were conducted on extruded Mg–8.20Gd–4.48Y–3.34Zn–0.36Zr alloy using a multistage hot compression test machine. Affected by reheating temperature, heating rate and isothermal holding time, dissolution of eutectic compounds and partial melting occurred during reheating, dynamic arrangement of alloying elements and phase transformation took place during subsequent rapid cooling. These microstructural behaviors not only changed the anisotropy in microstructural morphology of the extruded Mg–8.20Gd–4.48Y–3.34Zn–0.36Zr alloy, but also affected the anisotropy in forming properties of it. When this alloy was reheated to 580°C with a heating rate of 20°C/s and held isothermally for 20s, semisolid slurry without anisotropy in microstructural morphology and forming properties, exhibiting a homogeneous spherical microstructure was obtained.



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Epigenetic alterations in chronic disease focusing on Behçet’s disease: Review

Publication date: July 2017
Source:Biomedicine & Pharmacotherapy, Volume 91
Author(s): Shahriar Alipour, Mohammad Nouri, Ebrahim Sakhinia, Nasser Samadi, Neda Roshanravan, Abed Ghavami, Alireza Khabbazi
Objective'Epigenetics' is specified as the inheritable changes in gene expression with no alterations in DNA sequences. Epigenetics is a rapidly overspreading scientific field, and the study of epigenetic regulation in chronic disease is emerging. This study aims to evaluate epigenetic changes including DNA methylation, histone modification, and non-coding RNAs (ncRNAs) in inflammatory disease, with focus on Behçet's disease. In this review, first we describe the history and classification of epigenetic changes, and then the role of epigenetic alterations in chronic diseases is explained.MethodsSystematic search of MEDLINE, Embase, and Cochrane Library was conducted for all comparative studies since 2000 to 2015 with the limitations of the English language.ResultsFor a notable period of time, researchers have mainly focused on the epigenetic pathways that are involved in the modulation of inflammatory and anti-inflammatory genes. Recent studies have proposed a central role for chronic inflammation in the pathogenesis of chronic disease, including Behçet's disease.ConclusionStudies have been reported on the epigenetic of BD showed the role of alterations in the methylation level of IRS elements; histone modifications such as H3K4me27 and H3K4me3; up regulation of miR-182 and miR-3591-3p; down regulation of miR-155, miR-638 and miR-4488 in the pathogenesis of the disease.



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A comparison of PM exposure related to emission hotspots in a hot and humid urban environment: Concentrations, compositions, respiratory deposition, and potential health risks

Publication date: 1 December 2017
Source:Science of The Total Environment, Volumes 599–600
Author(s): Siming You, Zhiyi Yao, Yanjun Dai, Chi-Hwa Wang
Particle number concentration, particle size distribution, and size-dependent chemical compositions were measured at a bus stop, alongside a high way, and at an industrial site in a tropical city. It was found that the industry case had 4.93×10⁷–7.23×10⁷ and 3.44×10⁴–3.69×10⁴#/m³ higher concentration of particles than the bus stop and highway cases in the range of 0.25–0.65μm and 2.5–32μm, respectively, while the highway case had 6.01×10⁵ and 1.86×10³#/m³ higher concentration of particles than the bus stop case in the range of 0.5–1.0μm and 5.0–32μm, respectively. Al, Fe, Na, and Zn were the most abundant particulate inorganic elements for the traffic-related cases, while Zn, Mn, Fe, and Pb were abundant for the industry case. Existing respiratory deposition models were employed to analyze particle and element deposition distributions in the human respiratory system with respect to some potential exposure scenarios related to bus stop, highway, and industry, respectively. It was shown that particles of 0–0.25μm and 2.5–10.0μm accounted for around 74%, 74%, and 70% of the particles penetrating into the lung region, respectively. The respiratory deposition rates of Cr and Ni were 170 and 220 ng/day, and 55 and 140ng/day for the highway and industry scenarios, respectively. Health risk assessment was conducted following the US EPA supplemented guidance to estimate the risk of inhalation exposure to the selected elements (i.e. Cr, Mn, Ni, Pb, Se, and Zn) for the three scenarios. It was suggested that Cr poses a potential carcinogenic risk with the excess lifetime cancer risk (ELCR) of 2.1–98×10⁻⁵ for the scenarios. Mn poses a potential non-carcinogenic risk in the industry scenario with the hazard quotient (HQ) of 0.98. Both Ni and Mn may pose potential non-carcinogenic risk for people who are involved with all the three exposure scenarios.

Graphical abstract

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Retrograde Parotidectomy and facial nerve outcomes: A case series of 44 patients

The most common surgical method to remove benign parotid tumors remains the prograde approach. We examined if a retrograde surgical technique offers better outcomes than historical prograde controls.

http://ift.tt/2pQ3olx

A sustained increase of plasma fibrinogen in sudden sensorineural hearing loss predicts worse outcome independently

A number of etiologies of idiopathic sudden sensorineural hearing loss (ISSNHL) have been proposed. Vascular disturbance is one cause of ISSNHL and has been reported to be associated with fibrinogen. We aimed to determine whether hyperfibrinogenemia is associated with poor outcome and whether a serial change in fibrinogen level is associated with outcome.

http://ift.tt/2pPWpsN

Decreased clinic visits for acute respiratory infections following an adult tonsillectomy: A population-based study

This study attempted to investigate the effects of a tonsillectomy on utilization of medical resources for acute respiratory infections by comparing numbers and costs of clinic visits within 1year before and after a tonsillectomy.

http://ift.tt/2pQCTdW