A well-known hazardous metal and top contaminant in wastewater is hexavalent chromium. The two forms of most commonly found chromium are chromate ( CrO 4 2− ) and dichromate ( Cr 2 O 7 2− ). Leather tanning, cooling t...A well-known hazardous metal and top contaminant in wastewater is hexavalent chromium. The two forms of most commonly found chromium are chromate ( CrO 4 2− ) and dichromate ( Cr 2 O 7 2− ). Leather tanning, cooling tower blow-down, plating, electroplating, rinse water sources, anodizing baths etc. are the main sources of Cr (VI) contamination. The Cr (VI) is not only non-biodegradable in the environment but also carcinogenic to living population. It is still difficult to treat Cr contaminated waste water effectively, safely, eco-friendly, and economically. As a result, many techniques have been used to treat Cr (VI)-polluted wastewater, including adsorption, chemical precipitation, coagulation, ion-exchange, and filtration. Among these practices, the most practical method is adsorption for the removal of Cr (VI) from aqueous solutions, which has gained widespread acceptance due to the ease of use and affordability of the equipment and adsorbent. It has been revealed that Fe-based adsorbents’ oxides and hydroxides have high adsorptive potential to lower Cr (VI) content below the advised threshold. Fe-based adsorbents were also discovered to be relatively cheap and toxic-free in Cr (VI) treatment. Fe-based adsorbents are commonly utilized in industry. It has been discovered that nanoparticles of Fe-, Ti-, and Cu-based adsorbents have a better capacity to remove Cr (VI). Cr (VI) was effectively removed from contaminated water using mixed element-based adsorbents (Fe-Mn, Fe-Ti, Fe-Cu, Fe-Zr, Fe-Cu-Y, Fe-Mg, etc.). Initial findings suggest that Cr (VI) removal from wastewater may be accomplished by using magnesium ferrite nanomaterials as an efficient adsorbent.展开更多
乳腺癌(Breast cancer, BC)于2020年在全球新增癌症病例成为了最常见癌症,且发病率逐年升高。胶原蛋白是构成细胞外基质(Extracellular Matrix, ECM)的主要成分,近年来的研究发现III型胶原蛋白(Collagen Type III, COLIII)在乳腺癌的发...乳腺癌(Breast cancer, BC)于2020年在全球新增癌症病例成为了最常见癌症,且发病率逐年升高。胶原蛋白是构成细胞外基质(Extracellular Matrix, ECM)的主要成分,近年来的研究发现III型胶原蛋白(Collagen Type III, COLIII)在乳腺癌的发生、发展过程中发挥重要作用,并对肿瘤微环境(Tumor micro-environment, TME)的维持有重要意义。其中,癌症相关成纤维细胞(Cancer-associated fibroblasts, CAFs)在建立和重塑ECM结构中扮演关键角色,调控肿瘤细胞通过TME入侵的进程。但由于该体系庞大,通过分泌细胞因子和趋化因子与癌细胞相互作用的机制复杂,各成分及其亚型在癌症进展中的角色尚存争议。本文基于TME在乳腺恶性肿瘤中的研究现状以及作为ECM中重要成分的COLIII的性质结构、形态分布,分析COLIII通过改变ECM的机械力与刚度影响乳腺癌行为的机制,同时充分讨论特殊结构、来源的COLIII在微环境中的不同功能及作用方式,评估其应用于癌症治疗的可能性。展开更多
Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various ...Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various types of hazardous elements are required. Among such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future challenge. Different industrial ways to treat phosphate rock are currently being practised, and we have here studied how chromium behaves when using the nitro-phosphate process. The reduction mechanism of Cr (VI) in nitric acid and phosphoric acid solutions was investigated by measuring redox potential and UV-VIS spectra. The results show that Cr (VI) is not stable in strong nitric acid solutions. Reduction of Cr (VI) species decreased with decreasing temperature, NO<sub>2</sub> concentration, ionic strength and absence of light. These findings support the proposed reduction reaction:The reduction rate was observed proportional to the nitric acid decomposition: .展开更多
Metal trace elements (MTE) are among the most harmful micropollutants of natural waters. Eliminating them helps improve the quality and safety of drinking water and protect human health. In this work, we used mango ke...Metal trace elements (MTE) are among the most harmful micropollutants of natural waters. Eliminating them helps improve the quality and safety of drinking water and protect human health. In this work, we used mango kernel powder (MKP) as bioadsorbent material for removal of Cr (VI) from water. Uv-visible spectroscopy was used to monitor and quantify Cr (VI) during processing using the Beer-Lambert formula. Some parameters such as pH, mango powder, mass and contact time were optimized to determine adsorption capacity and chromium removal rate. Adsorption kinetics, equilibrium, isotherms and thermodynamic parameters such as ΔG˚, ΔH˚, and ΔS˚, as well as FTIR were studied to better understand the Cr (VI) removal process by MKP. The adsorption capacity reached 94.87 mg/g, for an optimal contact time of 30 min at 298 K. The obtained results are in accordance with a pseudo-second order Freundlich adsorption isotherm model. Finally FTIR was used to monitor the evolution of absorption bands, while Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to evaluate surface properties and morphology of the adsorbent.展开更多
Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly fo...Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly formation of a trivalent G-quadruplex/hemin DNAzyme for colorimetric detection of Hg^(2+).A hairpin DNA(Hr)was designed with thymine-Hg^(2+)-thymine pairs that catalyzed by Exo III is prompted to happen upon binding Hg^(2+).A released DNA fragment triggers the catalytic assembly of other three hairpins(H1,H2,and H3)to form many trivalent G-quadruplex/hemin DNA enzymes for signal output.The developed sensor shows a dynamic range from 2 pM to 2μM,with an impressively low detection limit of 0.32 pM for Hg^(2+)detection.Such a sensor also has good selectivity toward Hg^(2+)detection in the presence of other common metal ions.This strategy shows the great potential for visual detection with portable type.展开更多
目的:研究分析中青年视网膜静脉阻塞(Retinal Vein Occlusion, RVO)患者同型半胱氨酸(Homocysteine, Hcy)及抗凝血酶III (Antithrombin III, AT-III)水平,两者是否作为致病危险因素参与RVO发病。分析视网膜中央静脉阻塞(CRVO)和视网膜...目的:研究分析中青年视网膜静脉阻塞(Retinal Vein Occlusion, RVO)患者同型半胱氨酸(Homocysteine, Hcy)及抗凝血酶III (Antithrombin III, AT-III)水平,两者是否作为致病危险因素参与RVO发病。分析视网膜中央静脉阻塞(CRVO)和视网膜分支静脉阻塞(BRVO)危险因素的差异,为治疗和预防该病提供客观依据。方法:1) 所有研究对象选自2021年10月至2023年12月期间就诊于内蒙古自治区人民医院眼科的年龄 P > 0.05)。三组患者之间在Hcy、AT-III、胆固醇(CHOL)、叶酸、维生素B12、D-二聚体(D-D)、纤维蛋白降解产物(FDP)水平差异均有统计学意义(P P P < 0.001)。结论:1) Hcy水平升高和AT-III活性缺乏为中青年CRVO和BRVO的危险因素。2) 相对于BRVO患者,CRVO组中Hcy水平升高和AT-III缺乏的值更为显著。展开更多
A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement wi...A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement with 1, 2, 5, 8 Tetrahydroxyanthraquinone, (Quinalizarin, QINZ) at pH 1.5. The European Directive (2003/53/EC) limits the use of cements so that it contains no more than 2 mg.Kg-1 of water-soluble Cr (VI). The absorbance at 565 nm due to Cr (VI)-QINZ complex is recommended for the determination of water-soluble Cr (VI) in Portland cement. The quantification of Cr (VI) released from cement when mixed with water is performed according to TRGS 613 (Technical Rules of Hazardous Substances). The validity of the method is thoroughly examined and the proposed method gives satisfactory results. A derivative spectrophotometric method has been developed for the determination of total Cr (VI) in Portland cement in the presence of Fe (III) and Ti (IV). The hexavalent chromium complex formed at pH 1.5 allows precise and accurate determination of chromium (VI) over the concentration range 0.05 to 3.0 mg.L-1of chromium (VI). The validity of the method was examined by analyzing several Standard Reference Material (SRM) Portland cement samples. The MDL (at 95% confidence level) was found to be 25 ng/mL for chromium (VI) in National Institute of Standards and Technology (NIST) cement samples using the proposed method.展开更多
Acute chromium (III) toxicity in relation to Daphnia similis, most appropriate for Brazilian environment has been evaluated. The preliminary toxicity test showed that the median effective concentration was 10 mg/l. Af...Acute chromium (III) toxicity in relation to Daphnia similis, most appropriate for Brazilian environment has been evaluated. The preliminary toxicity test showed that the median effective concentration was 10 mg/l. After having performed the final test, the immobility percentage was calculated for each concentration in relation to the total number of the used organisms within the chosen pH range. It was shown that the proposed methodology rendered realistic results and the 48-h CE50 value under the test conditions is 3.24 mg/l. The minimum concentration that did not show any toxicity to Daphnia similis was 2.5 mg of chromium (III) per liter. The obtained level is superior to the maximum limit recommended by the Brazilian norms, 0.5 mg/l.展开更多
Chromium oxide nanoparticles were synthesized by the reduction of potassium dichromate solution with Mukia Maderaspatana plant extract. In electrochemical methods, Cr2O3 nanoparticles were synthesized by two ways, usi...Chromium oxide nanoparticles were synthesized by the reduction of potassium dichromate solution with Mukia Maderaspatana plant extract. In electrochemical methods, Cr2O3 nanoparticles were synthesized by two ways, using platinum (Pt) electrodes and K2Cr2O7 solution with H2SO4 as medium in the first case. And chromium doped platinum electrode (Pt/Cr) in presence of NaHCO3 solution in second case. The resulting Cr2O3 nanoparticles were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-VIS absorption and Fourier-transform infrared (FTIR) spectroscopy. The enhancing influence of Cr2O3 nanoparticles as a catalyst for the decomposition of KMnO4 has been studied. The antibacterial effect of Cr2O3 nanoparticles against E. coli was investigated. These particles were shown to have an effective bactericide.展开更多
The possibility of determining of chromium (III, VI) ions was investigated in this paper. It is shown that the electrode on а basis of heаzlewoodite has high selectivity to chromium (III) ions. Also the stability co...The possibility of determining of chromium (III, VI) ions was investigated in this paper. It is shown that the electrode on а basis of heаzlewoodite has high selectivity to chromium (III) ions. Also the stability constants of complexes, forming in system “Cr3+-Mohr’s salt-Ca(OH)2-PVA ÷ PAA” were determined by potentiometric titration with ion-selective electrode.展开更多
The extraction of chromium(III) from a model waste solution and also from a waste solution of an Indian tannery with Amberlite IR 120 resin is described, and the performance of this resin is compared with other simila...The extraction of chromium(III) from a model waste solution and also from a waste solution of an Indian tannery with Amberlite IR 120 resin is described, and the performance of this resin is compared with other similar resins. The parameters that were optimized include effect of mixing time, pH, loading and elution behaviours of chromium(III) for this resin. Sorption of chromium(III) on Amberlite IR 120 followed Freundlich isotherm and Langmuir isotherm model, and the maximum sorption capacity was determined to be 142.86 mg Cr(III)/g of the resin. Higher Freundlich constant (Kf) values (6.30 and 13.46 for aqueous feed of 500 and 1000 ppm Cr(III)) indicated strong chemical interaction through ion exchange mechanism of the metal ion with the resin. The kinetic data showed good fit to the Lagergren first order model for extraction of chromium(III). Desorption of chromium(III) from the loaded resin increased with the increase in concentration of eluent (5-20% H2SO4). With 20% (v/v) sulphuric acid solution 94% chromium(III) was eluted in three stages. Elution of the Cr(III) in the column experiments was however, found to be lower (82%) than that of the shake flask data. In case of Indian tannery’s waste solution, it was observed that almost total chromium was extracted in four stages with Amberlite IR 120.展开更多
文摘A well-known hazardous metal and top contaminant in wastewater is hexavalent chromium. The two forms of most commonly found chromium are chromate ( CrO 4 2− ) and dichromate ( Cr 2 O 7 2− ). Leather tanning, cooling tower blow-down, plating, electroplating, rinse water sources, anodizing baths etc. are the main sources of Cr (VI) contamination. The Cr (VI) is not only non-biodegradable in the environment but also carcinogenic to living population. It is still difficult to treat Cr contaminated waste water effectively, safely, eco-friendly, and economically. As a result, many techniques have been used to treat Cr (VI)-polluted wastewater, including adsorption, chemical precipitation, coagulation, ion-exchange, and filtration. Among these practices, the most practical method is adsorption for the removal of Cr (VI) from aqueous solutions, which has gained widespread acceptance due to the ease of use and affordability of the equipment and adsorbent. It has been revealed that Fe-based adsorbents’ oxides and hydroxides have high adsorptive potential to lower Cr (VI) content below the advised threshold. Fe-based adsorbents were also discovered to be relatively cheap and toxic-free in Cr (VI) treatment. Fe-based adsorbents are commonly utilized in industry. It has been discovered that nanoparticles of Fe-, Ti-, and Cu-based adsorbents have a better capacity to remove Cr (VI). Cr (VI) was effectively removed from contaminated water using mixed element-based adsorbents (Fe-Mn, Fe-Ti, Fe-Cu, Fe-Zr, Fe-Cu-Y, Fe-Mg, etc.). Initial findings suggest that Cr (VI) removal from wastewater may be accomplished by using magnesium ferrite nanomaterials as an efficient adsorbent.
文摘Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various types of hazardous elements are required. Among such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future challenge. Different industrial ways to treat phosphate rock are currently being practised, and we have here studied how chromium behaves when using the nitro-phosphate process. The reduction mechanism of Cr (VI) in nitric acid and phosphoric acid solutions was investigated by measuring redox potential and UV-VIS spectra. The results show that Cr (VI) is not stable in strong nitric acid solutions. Reduction of Cr (VI) species decreased with decreasing temperature, NO<sub>2</sub> concentration, ionic strength and absence of light. These findings support the proposed reduction reaction:The reduction rate was observed proportional to the nitric acid decomposition: .
文摘Metal trace elements (MTE) are among the most harmful micropollutants of natural waters. Eliminating them helps improve the quality and safety of drinking water and protect human health. In this work, we used mango kernel powder (MKP) as bioadsorbent material for removal of Cr (VI) from water. Uv-visible spectroscopy was used to monitor and quantify Cr (VI) during processing using the Beer-Lambert formula. Some parameters such as pH, mango powder, mass and contact time were optimized to determine adsorption capacity and chromium removal rate. Adsorption kinetics, equilibrium, isotherms and thermodynamic parameters such as ΔG˚, ΔH˚, and ΔS˚, as well as FTIR were studied to better understand the Cr (VI) removal process by MKP. The adsorption capacity reached 94.87 mg/g, for an optimal contact time of 30 min at 298 K. The obtained results are in accordance with a pseudo-second order Freundlich adsorption isotherm model. Finally FTIR was used to monitor the evolution of absorption bands, while Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to evaluate surface properties and morphology of the adsorbent.
基金Supported by The Science and Technology Project of General Administration of Quality Supervision,Inspection and Quarantine (2015IK126)The Science and Technology Project of Changsha City of Hunan Province of China (KQ1602124).
文摘Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly formation of a trivalent G-quadruplex/hemin DNAzyme for colorimetric detection of Hg^(2+).A hairpin DNA(Hr)was designed with thymine-Hg^(2+)-thymine pairs that catalyzed by Exo III is prompted to happen upon binding Hg^(2+).A released DNA fragment triggers the catalytic assembly of other three hairpins(H1,H2,and H3)to form many trivalent G-quadruplex/hemin DNA enzymes for signal output.The developed sensor shows a dynamic range from 2 pM to 2μM,with an impressively low detection limit of 0.32 pM for Hg^(2+)detection.Such a sensor also has good selectivity toward Hg^(2+)detection in the presence of other common metal ions.This strategy shows the great potential for visual detection with portable type.
文摘目的:研究分析中青年视网膜静脉阻塞(Retinal Vein Occlusion, RVO)患者同型半胱氨酸(Homocysteine, Hcy)及抗凝血酶III (Antithrombin III, AT-III)水平,两者是否作为致病危险因素参与RVO发病。分析视网膜中央静脉阻塞(CRVO)和视网膜分支静脉阻塞(BRVO)危险因素的差异,为治疗和预防该病提供客观依据。方法:1) 所有研究对象选自2021年10月至2023年12月期间就诊于内蒙古自治区人民医院眼科的年龄 P > 0.05)。三组患者之间在Hcy、AT-III、胆固醇(CHOL)、叶酸、维生素B12、D-二聚体(D-D)、纤维蛋白降解产物(FDP)水平差异均有统计学意义(P P P < 0.001)。结论:1) Hcy水平升高和AT-III活性缺乏为中青年CRVO和BRVO的危险因素。2) 相对于BRVO患者,CRVO组中Hcy水平升高和AT-III缺乏的值更为显著。
文摘A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement with 1, 2, 5, 8 Tetrahydroxyanthraquinone, (Quinalizarin, QINZ) at pH 1.5. The European Directive (2003/53/EC) limits the use of cements so that it contains no more than 2 mg.Kg-1 of water-soluble Cr (VI). The absorbance at 565 nm due to Cr (VI)-QINZ complex is recommended for the determination of water-soluble Cr (VI) in Portland cement. The quantification of Cr (VI) released from cement when mixed with water is performed according to TRGS 613 (Technical Rules of Hazardous Substances). The validity of the method is thoroughly examined and the proposed method gives satisfactory results. A derivative spectrophotometric method has been developed for the determination of total Cr (VI) in Portland cement in the presence of Fe (III) and Ti (IV). The hexavalent chromium complex formed at pH 1.5 allows precise and accurate determination of chromium (VI) over the concentration range 0.05 to 3.0 mg.L-1of chromium (VI). The validity of the method was examined by analyzing several Standard Reference Material (SRM) Portland cement samples. The MDL (at 95% confidence level) was found to be 25 ng/mL for chromium (VI) in National Institute of Standards and Technology (NIST) cement samples using the proposed method.
文摘Acute chromium (III) toxicity in relation to Daphnia similis, most appropriate for Brazilian environment has been evaluated. The preliminary toxicity test showed that the median effective concentration was 10 mg/l. After having performed the final test, the immobility percentage was calculated for each concentration in relation to the total number of the used organisms within the chosen pH range. It was shown that the proposed methodology rendered realistic results and the 48-h CE50 value under the test conditions is 3.24 mg/l. The minimum concentration that did not show any toxicity to Daphnia similis was 2.5 mg of chromium (III) per liter. The obtained level is superior to the maximum limit recommended by the Brazilian norms, 0.5 mg/l.
文摘Chromium oxide nanoparticles were synthesized by the reduction of potassium dichromate solution with Mukia Maderaspatana plant extract. In electrochemical methods, Cr2O3 nanoparticles were synthesized by two ways, using platinum (Pt) electrodes and K2Cr2O7 solution with H2SO4 as medium in the first case. And chromium doped platinum electrode (Pt/Cr) in presence of NaHCO3 solution in second case. The resulting Cr2O3 nanoparticles were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-VIS absorption and Fourier-transform infrared (FTIR) spectroscopy. The enhancing influence of Cr2O3 nanoparticles as a catalyst for the decomposition of KMnO4 has been studied. The antibacterial effect of Cr2O3 nanoparticles against E. coli was investigated. These particles were shown to have an effective bactericide.
文摘The possibility of determining of chromium (III, VI) ions was investigated in this paper. It is shown that the electrode on а basis of heаzlewoodite has high selectivity to chromium (III) ions. Also the stability constants of complexes, forming in system “Cr3+-Mohr’s salt-Ca(OH)2-PVA ÷ PAA” were determined by potentiometric titration with ion-selective electrode.
文摘The extraction of chromium(III) from a model waste solution and also from a waste solution of an Indian tannery with Amberlite IR 120 resin is described, and the performance of this resin is compared with other similar resins. The parameters that were optimized include effect of mixing time, pH, loading and elution behaviours of chromium(III) for this resin. Sorption of chromium(III) on Amberlite IR 120 followed Freundlich isotherm and Langmuir isotherm model, and the maximum sorption capacity was determined to be 142.86 mg Cr(III)/g of the resin. Higher Freundlich constant (Kf) values (6.30 and 13.46 for aqueous feed of 500 and 1000 ppm Cr(III)) indicated strong chemical interaction through ion exchange mechanism of the metal ion with the resin. The kinetic data showed good fit to the Lagergren first order model for extraction of chromium(III). Desorption of chromium(III) from the loaded resin increased with the increase in concentration of eluent (5-20% H2SO4). With 20% (v/v) sulphuric acid solution 94% chromium(III) was eluted in three stages. Elution of the Cr(III) in the column experiments was however, found to be lower (82%) than that of the shake flask data. In case of Indian tannery’s waste solution, it was observed that almost total chromium was extracted in four stages with Amberlite IR 120.