Chelant-enhanced washing of CCA-contaminated soil: Coupled with selective dissolution or soil stabilization

Beiyuan, Jingzi,Lau, Abbe Y.T.,Tsang, Daniel C.W.,Zhang, Weihua,Kao, Chih-Ming,Baek, Kitae,Ok, Yong Sik,Li, Xiang-Dong Elsevier 2018 Science of the Total Environment Vol.612 No.-

<P><B>Abstract</B></P> <P>Remediation of CCA-contaminated soil (Cr, Cu, and As) by biodegradable chelant-enhanced washing (EDDS, <I>S,S</I>-ethylene-diamine-disuccinic-acid) needs further enhancement. This study investigated the effectiveness of coupling with pre-treatment by selective dissolution and post-treatment by soil amendments, respectively. Three groups of reagents (reductants, alkaline solvents, and organic ligands) were adopted in the pre-treatment to dissolve the oxide minerals before EDDS extraction. In the post-treatment, soil amendments (coal fly ash (CFA), acid mine drainage sludge (AMDS), green waste compost (GWC)), and their mixtures) were used for a 2-month stabilization after 2-h EDDS washing. Multi-endpoint evaluation was performed by assessing the chemical state, leachability, mobility, bioaccessibility, and plant-availability of residual metal(loid)s as well as the cytotoxicity, enzyme activities, and available nutrients of the treated soils. Pre-treatment by dithionite-citrate-bicarbonate significantly enhanced extraction efficiency, but also increased the leachability of As and Cr and bioaccessibility of Cr in the treated soils. While sodium hydroxide removed the majority of As without increasing its leachability and bioaccessibility, it increased the cytotoxicity and inhibited the acid phosphatase activity. Post-treatment with AMDS and CFA effectively controlled the mobility and leachability of residual As and Cr after EDDS washing. However, destabilized Cu was only marginally immobilized by GWC due to strong Cu-EDDS complexation. The bioaccessibility and phytoavailability of Cu was primarily reduced by EDDS washing, while those of As and Cr could be attenuated by AMDS and CFA. This study indicates that coupling chemical extraction with subsequent soil amendment plays complementary roles in mitigating effects of residual metal(loid)s and improving environmental quality.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Selective dissolution improved the removal efficiency of Cr, Cu, and As. </LI> <LI> Leachability and bioaccessibility of residual metal(loid)s were increased. </LI> <LI> NaOH washing boosted cytotoxicity and inhibited acid phosphatase activity. </LI> <LI> Mobility and leachability of residual metal(loid)s were curbed by CFA and AMDS. </LI> <LI> In contrast, bioaccessibility and plant-availability were reduced only by EDDS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Combined application of EDDS and EDTA for removal of potentially toxic elements under multiple soil washing schemes

Beiyuan, Jingzi,Tsang, Daniel C.W.,Valix, Marjorie,Baek, Kitae,Ok, Yong Sik,Zhang, Weihua,Bolan, Nanthi S.,Rinklebe, Jö,rg,Li, Xiang-Dong Elsevier 2018 CHEMOSPHERE - Vol.205 No.-

<P><B>Abstract</B></P> <P>Chelant-enhanced soil washing, such as EDTA (ethylenediaminetetraacetic acid) and biodegradable EDDS ([<I>S,S</I>]-ethylene-diamine-disuccinic acid), has been widely studied, however, EDTA is persistent under natural conditions while EDDS has a low efficiency for Pb extraction. Therefore, we investigated the efficacy of mixed chelants (EDDS and EDTA mixture at 1:1 M ratio) for the removal of Cu, Zn, and Pb from a field-contaminated soil using various washing schemes (multi-pulse, step-gradient chelant, and continuous washing schemes). Speciation modelling of the target metals, mineral elements, and EDDS/EDTA was performed, while the leachability and bioaccessibility of residual metals in the treated soils were also assessed. Our results suggested that the combined use of EDDS and EDTA reached equivalent extraction efficiency of the target metals as EDTA, i.e., 50% reduction in the dosage of EDTA was made possible. This was accomplished by selective extraction of Cu by EDDS and Pb by EDTA, which was supported by the results of speciation calculation. Multi-pulse washing scheme with intermittent water rinsing steps removed entrapped metal-chelant complexes and free chelants, therefore reducing the leachability and bioaccessibility of residual metals in the treated soils. Step-gradient chelant washing with the maximum dosage of chelants in the first washing step only achieved marginal improvement but undesirably promoted Pb bioaccessibility. Continuous washing for 24 h enhanced metal extraction but promoted mineral dissolution, together with a large amount of uncomplexed chelants and increase in Cu leachability. Thus the combined use of EDDS and EDTA in multi-pulse washing is recommended for further studies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mixture of EDDS and EDTA extracted comparable amount of PTEs as EDTA washing. </LI> <LI> Mixed chelants allowed complementary metal complexation and higher efficiency. </LI> <LI> Multi-pulse washing better utilized chelants and reduced leachability/bioaccessibility. </LI> <LI> Step-gradient chelant dosage hardly improved extraction but increased bioaccessible Pb. </LI> <LI> Continuous washing increased amounts of uncomplexed chelants and dissolved minerals. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Tunable magnetic properties of double perovskite La₂Fe_2-xCo_xO₆

Wang, Weihua,Feng, Wuwei,Yuan, Jiangyan,Pang, Ning,Zhao, Xiaoxue,Li, Meiyun,Bao, Zhidi,Zhu, Kun,Odkhuu, Dorj Elsevier 2018 PHYSICA B-CONDENSED MATTER - Vol.540 No.-

<P><B>Abstract</B></P> <P>Double perovskite La<SUB>2</SUB>Fe<SUB>2-x</SUB>Co<SUB>x</SUB>O<SUB>6</SUB> was prepared and studied. Orthorhombic and trigonal structures were obtained depend on the molar ratio of Fe to Co. Fe-rich sample demonstrate ferrimagnetic properties; with increasing content of Co, trigonal structure is favored and the net magnetic moment of sample decrease gradually to zero. Our experimental results were further supported by first-principle theoretical calculations and demonstrate that La<SUB>2</SUB>Fe<SUB>2-x</SUB>Co<SUB>x</SUB>O<SUB>6</SUB> is a new high <I>T</I> <SUB> <I>c</I> </SUB> ferromagnetic semiconductor with tunable magnetic properties and is thus a promising material for spintronics devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phase-pure double perovskite La2Fe2-xCoxO6 was prepared. </LI> <LI> Orthorhombic and trigonal structures were obtained depending on the ratio of Fe to Co. </LI> <LI> La2Fe2-xCoxO6 is a new high Tc ferromagnetic semiconductor with tunable magnetic properties. </LI> <LI> Theoretical ab initio calculations further support our experimental results. </LI> </UL> </P>

Phylogenetic and functional analysis of TGF-β/Smad2 pathway genes in cotton bollworm, Helicoverpa armigera

Li Yan,Lu Qin,Luo Hailing,Xia Shunchao,Li Haiyin,Xu Weihua 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.4

Transforming growth factor-beta (TGF-β) signaling pathway plays important roles in embryonic development, cell proliferation and tissue differentiation in vertebrates. Our previous studies demonstrated that TGF-β signal activates Smad1-POU-TFAM and PP2A-Akt pathways to regulate pupal diapause in Helicoverpa armigera. In this study, we investigated the function of TGF-β activates Smad2 pathway in H. armigera. Phylogenetic analysis of H. armigera TGF-β receptor I (TGFβRI), Smad2, Smad4 genes showed high conservation across species. In vitro experiments showed that TGFβRI was localized in the cell membrane where it binds Smad2 leading to the phosphorylation of Smad2. Smad4 was mainly localized in the cytoplasm, and bind to Smad2. Protein expression analysis showed that expression of TGFβRI, Smad4, Smad2, p-Smad2 were lower in diapause-destined pupae compared with nondiapause-destined pupae. Notably, treatment with 20-hydroxyecdysone (20E) increased expression of the above proteins. Inhibition of TGF-β/Smad2 signaling pathway delayed pupal development. These findings indicate that TGF-β/Smad2 pathway is involved in pupal development or diapause in H. armigera.

Path Tracking and Local Obstacle Avoidance for Automated Vehicle Based on Improved Artificial Potential Field

Weihua Li,Yipeng Wang,Junlong Guo,Dianbo Ren,Jianfeng Wang,Shengkai Zhu,Jianping Xiao,Shijuan Chen 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.5

This study proposes an improved artificial potential field (APF) by considering the cooperative control of local obstacle avoidance and path tracking for automated vehicles. We established the path gravitational potential field (GPF) based on the scheduled path (SP), including the lateral and longitudinal GPFs, to enable the automated vehicle to quickly return to the SP and track after obstacle avoidance, while maintaining control of speed for the entire process. To address the local optimal solution problem of the classical APF, we proposed a sub-target-point selection strategy based on the information of obstacles and SP and established the GPF of the sub-target points. Thus, the automated vehicle can avoid obstacles and quickly return to the SP. Furthermore, the relative velocity of the automated vehicle and the obstacle was used to establish the velocity repulsion potential field (RPF), which improved the adaptability of the APF to dynamic obstacles. The simulation results indicate that the improved APF is capable of cooperative control of path tracking and local obstacle avoidance. Code is available at https://github.com/xiaowang617/Improve-APF.

The Up-Regulation of miR-199b-5p in Erythroid Differentiation Is Associated with GATA-1 and NF-E2

Li, Yuxia,Bai, Hua,Zhang, Zhongzu,li, Weihua,Dong, Lei,Wei, Xueju,Ma, Yanni,Zhang, Junwu,Yu, Jia,Sun, Guotao,Wang, Fang Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.3

MicroRNAs (miRNAs) represent a class of small non-coding regulatory RNAs that play important roles in normal hematopoiesis, including erythropoiesis. Although studies have identified several miRNAs that regulate erythroid commitment and differentiation, we do not understand the mechanism by which the crucial erythroid transcription factors, GATA-1and NF-E2 directly regulate and control differentiation via miRNA pathways. In this study, we identified miR-199b-5p as a key regulator of human erythropoiesis, and its expression was up-regulated during the erythroid differentiation of K562 cells. Furthermore, the increase of miR-199b-5p in erythroid cells occurred in a GATA-1- and NF-E2-dependent manner during erythrocyte maturation. Both GATA-1 and NF-E2 bound upstream of the miR-199b gene locus and activated its transcription. Forced expression of miRNA-199b-5p in K562 cells affected erythroid cell proliferation and maturation. Moreover, we identified c-Kit as a direct target of miR-199b-5p in erythroid cells. Taken together, our results establish a functional link among the erythroid transcription factors GATA-1/NF-E2, miR-199b-5p and c-Kit, and provide new insights into the coupling of transcription and post-transcription regulation in erythroid differentiation.

Facile, Efficient Liquid Exfoliated Cyanoethylated Cellulose Nanofibrils and Their Application

Weihua Zhang,Mingjie Li,Chunlin Xu,Chaoxu Li 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

Traditionally, cellulose nanofibers are difficult to disperse in organic solvent and redisperse after drying, and thereby limit their practical applications. Herein, we develop a new, convenient, scalable and energy efficient method for producing cyanoethylated cellulose nanofibers. Through the synergy of mechanical and chemical reaction processes, the produced cyanoethylated cellulose nanofibers are ca. 3 nm wide and several hundred to 1000 nanometers long. Particularly, compared with common TEMPO oxidized cellulose nanofibrils, they show improved hydrophobicity and redispersibility in different organic solvent. In addition, these dispersed CCNFs also exhibit greater potential to construct high-performance structural materials, e.g., transparent ductile nanopapers with large elongation up to 18% and toughness as high as 16.5 MJ/m³.

Air horizontal jets into quiescent water

Weichao Li,Zhaoming Meng,Jianchuang Sun,Weihua Cai,Yandong Hou Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

Gas submerged jet is an outstanding thermohydraulic phenomenon in pool scrubbing of fission products during a severe nuclear accident. Experiments were performed on the hydraulic characteristics in the ranges of air mass flux 0.1-1400 kg/m²s and nozzle diameter 10-80 mm. The results showed that the dependence of inlet pressure on the mass flux follows a power law in subsonic jets and a linear law in sonic jets. The effect of nozzle submerged depth was negligible. The isolated bubbling regime, continuous bubbling regime, transition regime, and jetting regime were observed in turn, as the mass flux increased. In the bubbling regime and jetting regime, the air volume fraction distribution was approximately symmetric in space. Themelis model could capture the jet trajectory well. In the transition regime, the air volume fraction distribution loses symmetry due to the bifurcated secondary plume. The Li correlation and Themelis model showed sufficient accuracy for the prediction of jet penetration length.

Electrophysiological and behavioral responses of Asian and European honeybees to pear flower volatiles

Ma Weihua,Long Denglong,Wang Yi,Li Xinyu,Huang Jiaxing,Shen Jinshan,Su Wenting,Jiang Yusuo,Li Jie 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

Honeybee pollination behavior is influenced by flower volatiles, which honeybees sense via olfactory receptors. Honeybees are only weakly attracted to pear flowers. To investigate the potential reasons, we extracted and determined the floral volatile compounds from three pear cultivars (Su, Ya, and Xuehua) using headspace solidphase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC–MS). The effects of pear flower volatiles on the Asian honeybee (Apis cerana cerana Fabricius) and the European honeybee (Apis mellifera ligustica Spinola) were determined by electroantennogram (EAG) assays and behavioral tests in a three-arm olfactometer. Among the 76 flower volatiles detected with GC–MS, 21 were found in all three pear cultivars, accounting for approximately 70% of the total volatile content. 3-Methyl-1-butanol and (+)-limonene volatiles had the highest relative content. Five compounds elicited strong EAG responses in both bee species: 2-methylbu tyraldehyde, 1-nonanal, 6-methyl-5-hepten-2-one, 3-methyl-1-butanol, and (+)-limonene. Neither bee species showed positive taxis to these volatiles. In behavioral tests, A. mellifera ligustica showed a low preference for 6-methyl-5-hepten-2-one (20%, 400 µg/µL) and 2-phenethyl alcohol (16.7%, 400 µg/µL). Apis cerana cerana showed a low preference for 6-methyl-5-hepten-2-one (6.7%, 400 µg/µL) and 1-nonanal (10%, 400 µg/µL), whereas its preferences for 3-methyl-1-butanol (43.3%, 400 µg/µL) and α-farnesene (40%, 400 µg/µL) were similar to that for the control. Therefore, a lack of attractive volatile compounds could explain why honeybees are only weakly attracted to pear flowers. Therefore, to achieve acceptable pollination in pear orchards, we suggest using flower-scent sugar syrup feeding and a saturation pollination strategy.

The Up-Regulation of miR-199b-5p in Erythroid Differentiation Is Associated with GATA-1 and NF-E2

Yuxia Li,Hua Bai,Zhongzu Zhang,Weihua li,Lei Dong,Xueju Wei,Yanni Ma,Junwu Zhang,Jia Yu,Guotao Sun,Fang Wang 한국분자세포생물학회 2014 Molecules and cells Vol.37 No.3

MicroRNAs (miRNAs) represent a class of small non-co-ding regulatory RNAs that play important roles in normal hematopoiesis, including erythropoiesis. Although studies have identified several miRNAs that regulate erythroid commitment and differentiation, we do not understand the mechanism by which the crucial erythroid transcription factors, GATA-1and NF-E2 directly regulate and control differentiation via miRNA pathways. In this study, we identified miR-199b-5p as a key regulator of human erythropoiesis, and its expression was up-regulated during the erythroid differentiation of K562 cells. Furthermore, the increase of miR-199b-5p in erythroid cells occurred in a GATA-1- and NF-E2-dependent manner during erythrocyte maturation. Both GATA-1 and NF-E2 bound upstream of the miR-199b gene locus and activated its transcription. Forced expression of miRNA-199b-5p in K562 cells affected erythroid cell proliferation and maturation. Moreover, we identified c-Kit as a direct target of miR-199b-5p in erythroid cells. Taken together, our results establish a functional link among the erythroid transcription factors GATA-1/NF-E2, miR-199b-5p and c-Kit, and provide new insights into the coupling of transcription and post-transcription regulation in erythroid differentiation.