Exploring the interference mechanisms of surface and aqueous complexes with groundwater arsenate and arsenite adsorption.

Ca2+, Mg2+, and HCO3- are extremely common coexisting ions with arsenic (As) in geogenic As-polluted groundwaters. Although extensive research has improved our knowledge of groundwater As removal techniques and mechanisms, there is still a lack of a definite explanation of the distinct influences of Ca2+ and Mg2+ on As immobilization. Furthermore, the question of whether the occurrence of metal-As aqueous complexes has positive or detrimental effects on As adsorption is still open, which hinders our ability to predict the effectiveness of groundwater As removal. The goal of our present work was to investigate the molecular-level interference mechanisms of Ca2+, Mg2+, and HCO3- on arsenic adsorption with batch/column filtration experiments and spectroscopic techniques. The results showed that the co-presence of Ca2+ and As significantly increased As(V) and As(III) adsorption by 22.1 and 12.2% in batch studies and by 20.1 and 16.7% in column adsorptive filtrations, which could be explained by forming a ternary Ca-As-TiO2 complex. Without the surface complex, Mg2+ only had a slightly positive effect on As removal. Co-existence of Ca2+ and HCO3- prevented the generation this surface complex, which significantly decreased the elimination of As(III). Inversely, the As(V) ternary complex and adsorption were not interfered by HCO3-. Moreover, an aqueous Ca-As(V) complex was detected without surface, which facilitated generation of the surface complex and As(V) adsorption. The results of this work clarified the distinct effects of Ca2+ and Mg2+ and As(V) and As(III) adsorption, which was critical in predicting the As adsorption efficiency in column filtration processes.

Optofluidic zoom system with increased field of view and less chromatic aberration.

Imaging systems are widely used in many fields. However, there is an inherent compromise between field of view (FOV) and resolution. In this paper, we propose an optofluidic zoom system with increased FOV and less chromatic aberration, which can realize switching between large FOV and high resolution. The proposed system consists of a liquid prism, a zoom objective, an image sensor and image processing module, which can realize optical zoom and deflection. The proposed system achieves non-mechanical optical zoom from f = 40.5 mm to f = 84.0 mm. Besides, the angular resolution of zoom objective is up to 26"18 at f = 84.0 mm. The deflection range is ±10°, and the whole FOV of proposed system can reach up to 30.3°. The proposed system is compact and easy to machine. In addition, we reduce chromatic aberration produced by the liquid prism significantly. The proposed system can be used in monitor system, target tracking system, telescope system and so on.

Effect of aeration/micro-aeration on lignocellulosic decomposition, maturity and seedling phytotoxicity during full-scale biogas residues composting.

With the accelerated construction of biogas plants, the amount of biogas residues are expanding. Composting has been widely implemented to deal with biogas residues. Aeration regulation is the main factor affecting the post-composting treatment of biogas residues as high-quality fertilizer or soil amendment. Therefore, this study aimed to investigate the impact of different aeration regulations on full-scale biogas residues compost maturity by controlling oxygen concentration under micro-aeration and aeration conditions. Results showed that micro-aerobic extended the thermophilic stage of 17 days at above 55 ℃ and facilitated the mineralization process of organic nitrogen into nitrate nitrogen to retain higher N nutrition levels compared to aerobic treatment. For biogas residues with high moisture, aeration should be regulated at different full-scale composting stages. Total organic carbon (TOC), NH4+-N, NO3--N, total potassium (TK), total phosphorus (TP) and the germination index (GI) could be used to evaluate stabilization, fertilizer efficiency and phytotoxicity of compost with frequent monitoring times. However, seedling growth trials were still necessary in full-scale composting plants when changing of composting process or biogas residues feedstock.

Low-molecular-weight organic acid-mediated tolerance and Pb accumulation in centipedegrass under Pb stress.

Lead (Pb) is one of the most harmful, toxic pollutants to the ecological environment and humans. Centipedegrass, a fast-growing warm-season turfgrass, is excellent for Pb pollution remediation. Exogenous low-molecular-weight organic acid (LMWOA) treatment is a promising approach for assisted phytoremediation. However, the effects of this treatment on the tolerance and Pb accumulation of centipedegrass are unclear. This study investigated these effects on the physiological growth response and Pb accumulation distribution characteristics of centipedegrass. Applications of 400 µM citric acid (CA), malic acid (MA) and tartaric acid (TA) significantly reduced membrane lipid peroxidation levels of leaves and improved biomass production of Pb-stressed plants. These treatments mainly increased peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) activities and enhanced free protein (Pro), ascorbic acid (AsA) and phytochelatins (PCs) contents, ultimately improving the Pb tolerance of centipedegrass. Their promoting effects decreased as follows: TA>CA>MA. All the treatments decreased root Pb concentrations and increased stem and leaf Pb concentrations, thus increasing total Pb accumulation and TF values. MA had the best and worst effects on Pb accumulation and Pb transportation, respectively. CA had the best and worst effects on Pb transportation and Pb accumulation, respectively. TA exhibited strong effects on both Pb accumulation and transport. Furthermore, all treatments changed the subcellular Pb distribution patterns and distribution models of the chemical forms of Pb in each tissue. The root Pb concentration was more highly correlated with the Pb subcellular fraction distribution pattern, while the stem and leaf Pb concentrations were more highly correlated with the distribution models of the chemical forms of Pb. Overall, TA improved plant Pb tolerance best and promoted both Pb absorption and transportation well and is considered the best candidate for Pb-contaminated soil remediation with centipedegrass. This study provides a new idea for Pb-contaminated soil remediation with centipedegrass combined with LMWOAs.

Electrochemical activation of peroxymonosulfate (PMS) by carbon cloth anode for sulfamethoxazole degradation.

Electrochemical activation of peroxymonosulfate (PMS) at carbon cloth anode (E (Carbon cloth Anode)/PMS system) was investigated for sulfamethoxazole (SMX) degradation. The results indicated that PMS could be activated at carbon cloth anode during electrolysis, resulting in the improvement of SMX degradation. The degradation efficiency of SMX was facilitated with the higher PMS concentration and current density, respectively. The degradation rate constant of SMX increased with the rising pH from 3.6 to 6.0, and reached the highest value at pH 6.0, and then decreased with further increasing pH to 8.0. The presence of chloride ion (Cl-, 5-100 mM) significantly enhanced SMX degradation, while addition of humic acid (HA, 1-5 mgC L-1) inhibited SMX degradation. Addition of carbonate (HCO3-, 5-20 mM) had a negligible impact on SMX degradation. Small amounts of phosphate (PO43-, 0-5 mM) could promote degradation, while a large amount of PO43- (10-20 mM) inhibited the degradation. Moreover, the quenching experiments demonstrated that sulfate radical (SO4·-), hydroxyl radical (·OH) and singlet oxygen (1O2) contributed to SMX degradation in E (Carbon cloth Anode)/PMS system. The degradation intermediates of SMX were identified by LC-MS/MS and the degradation pathways were deduced to be hydroxylation, the cleavage of S-N bond, and oxidation of aniline group. Moreover, the micronucleus test of Vicia faba root tips indicated that the E (Carbon Cloth Anode)/PMS system could reduce the genetic toxicity of SMX contaminated water to some extent.

NTA-assisted mineral element and lead transportation in Eremochloa ophiuroides (Munro) Hack.

Lead (Pb) is one of the most toxic and harmful pollutants to the environment and human health. Centipedegrass (Eremochloa ophiuroides (Munro) Hack.), an excellent ground cover plant for urban plant communities, exhibits the outstanding lead tolerance and accumulation. Nitrilotriacetic acid (NTA) is an environmentally friendly chelating agent that strengthens phytoremediation. This study explored the effects of different NTA concentrations on the absorption and transportation of mineral elements and Pb in centipedegrass. Following exposure to Pb (500 µM) for 7 days in hydroponic nutrient solution, NTA increased root Mg, K, and Ca concentrations and shoot Fe, Cu, and Mg concentrations and significantly enhanced the translocation factors of mineral elements to the shoot. Although NTA notably decreased root Pb absorption and accumulation, it significantly enhanced Pb translocation factors, and the Pb TF value was the highest in the 2.0 mM NTA treatment. Furthermore, the shoot translocation of Pb and mineral elements was synergistic. NTA can support mineral element homeostasis and improve Pb translocation efficiency in centipedegrass. Regarding root radial transport, NTA (2.0 mM) significantly promoted Pb transport by the symplastic pathway under the treatments with low-temperature and metabolic inhibitors. Meanwhile, NTA increased apoplastic Pb transport at medium and high Pb concentrations (200-800 µM). NTA also enhanced the Pb radial transport efficiency in roots and thus assisted Pb translocation. The results of this study elucidate the effects of NTA on the absorption and transportation of mineral elements and Pb in plants and provide a theoretical basis for the practical application of the biodegradable chelating agent NTA in soil Pb remediation.

Melatonin-assisted phytoremediation of Pb-contaminated soil using bermudagrass.

Exogenous application of melatonin to plants is a promising approach for assisted phytoremediation of soil lead (Pb). In this study, we investigated the effects of foliar applications of melatonin to mature bermudagrass (Cynodon dactylon (L.) Pers.), a fast-growing perennial with potential as a non-hyperaccumulator plant for Pb phytoremediation. Following exposure to Pb (3000 mg kg-1) for 30 days, decreases in biomass and chlorophyll production, degradation of thylakoid membranes, reduced photosynthesis and PSII (reaction center of photosystem II) efficiency, and elevated oxidative stress were found. Foliar applications of melatonin to Pb-stressed bermudagrass mitigated these negative effects, restoring photosynthetic pigments and chloroplast ultrastructure, subsequently improving photosynthesis and photochemistry efficiency of PSII. Exogenous melatonin also eliminated the excessive accumulations of reactive oxygen species (ROS) and methylglyoxal (MG) which associated with cellular redox homeostasis by improving ascorbic acid (AsA) and reduced glutathione (GSH) contents, redox status of GSH/GSSG (oxidative glutathione), and key enzymes activities in both AsA-GSH and glyoxalase systems. Ultimately, treating bermudagrass plants with exogenous melatonin elevated biomass production and disproportionally greater Pb translocation to roots and senescent leaves. This collectively resulted in 21% greater recovery of Pb compared to Pb-stressed bermudagrass lacking melatonin application. Overall, results from this study demonstrated the beneficial roles of melatonin for improving the effectiveness of bermudagrass as a non-hyperaccumulator plant for soil Pb phytoremediation.

Zn2+ adsorption from wastewater using a chitosan/ß-cyclodextrin-based composite membrane.

In this study, a ß-cyclodextrin polymer (ß-CDP) was synthesized by pretreating ß-cyclodextrin (ß-CD) with citric acid (CA), and then, chitosan (CTS) and ß-CDP were cross-linked to prepare a biomass-based (CTS/ß-CDP) composite membrane. The effects of the preparation conditions in sodium hydroxide on the adsorption amount and adsorption rate of zinc ions (Zn2+ ) from simulated wastewater were investigated. The results showed that a maximum adsorption amount 123.7 µg/g and adsorption rate 94.14% of Zn2+ were obtained when the reaction between CTS and ß-CDP was performed at 50°C, the concentration of acetic acid was 2%, dissolving ß-CDP water dosage was 30 ml, and the soaking time in sodium hydroxide was 1 hr. Comparative studies on the adsorption of CTS membranes, ß-CD, ß-CDP, and CTS/ß-CDP composite membrane showed that the CTS/ß-CDP composite membrane had the highest Zn2+ adsorption efficiency. The CTS/ß-CDP composite membrane was characterized by FTIR, SEM, and XRD. Characteristic absorption peaks of CTS and ß-CDP appeared in the FTIR spectra of the CTS/ß-CDP composite membrane, confirming its synthesis. The SEM images showed that the surface of the composite membrane was rougher than the porous CTS membrane, which increased the number of adsorption sites and the adsorption efficiency. XRD patterns showed that the CTS/ß-CDP composite membrane was amorphous, indicating that ß-CDP changed the crystal structure of the CTS. The swelling degree and transmittance of the CTS/ß-CDP composite membrane were lower than the CTS membrane, which should be conducive to recycling after wastewater treatment. PRACTICAL APPLICATIONS: Industrial wastewater often contains heavy metal ions such as Zn2+ , which are difficult to degrade and are highly toxic, and direct wastewater discharge can greatly harm the ecosystems and humans. In this study, CTS and ß-CD were cross-linked to synthesize a biomass membrane for adsorbing Zn2+ to reduce the Zn2+ content in wastewater via adsorption.The results show that the CTS/ß-CDP composite membrane can be applied to small-scale wastewater treatment fields such as food and chemical industry. After the Zn2+ -containing wastewater underwent pretreatment, the composite membrane was placed into the wastewater for effective adsorption, which could achieve high adsorption efficiency. The process played a major role in effectively treating Zn2+ and other difficult to degrade heavy metal ions; thereby, simplifying Zn2+ -containing wastewater. The treatment process reduces the investment and operating costs of sewage treatment, and at the same time, has a significant removal effect, and hence, can meet the requirements of environmental protection discharge.

Particle size distribution mathematical models and properties of suspended solids in a typical freshwater pond.

Many countries, such as China, today are facing the scarcity and pollution issues of freshwater resources. Suspended solids, as wastewater contaminants, may contain components such as nitrogen, phosphorus, heavy metals and pathogens that are harmful to the environment and human health, it is essential to know the size distribution regularity of the solids with a view to guiding the management of freshwater resources for sustainability. Particle size distribution (PSD) mathematical models and properties of suspended solids in a typical freshwater pond were investigated in this study. Particle size was measured using a laser particle size analyzer (measurement range: 0.01-3500 µm). The power law model and the variable-ß model were tested for their ability to fit the numeric distribution of suspended solids; Gaussian (i.e., normal) distribution and log-normal distribution models were used to evaluate the volumetric distribution of suspended solids. The results showed that: by number, about 80% of the particles contributed to only 10% of total particle volume, while the remaining 20% contributed about 90% of the total volume. For numeric distribution, the variable-ß model (R2 = 0.975 ±â€¯0.011) was better than the power law model (R2 = 0.899 ±â€¯0.033); for the volumetric distribution, the log-normal distribution model (R2 = 0.968 ±â€¯0.020) clearly outperformed the Gaussian distribution model (R2 = 0.655 ±â€¯0.093). Overall, the variable-ß model and log-normal distribution were shown to accurately describe the numerical and volumetric distribution of pond water suspended solids, respectively. PSD model parameters can be related to some compositions in the wastewater and can provide guidance for suspended solids further treatment, be it physical, biological, chemical or synthetic methods.

Synthesis and properties of a clean and sustainable deicing additive for asphalt mixture.

A clean and sustainable deicing additive was prepared via the adsorption of acetate anions (Ac-) by magnesium (Mg) and aluminum (Al) calcined layered double hydroxide (Mg/Al-CLDH). Fourier transform infrared spectroscopy spectrums proved that Ac- had intercalated into LDH structure. X-ray diffraction patterns, scanning electron microscopy and transmission electron microscopy images showed that the intercalation spacing and platelet thickness of Mg and Al layered double hydroxide containing Ac- anions (Mg/Al-Ac- LDH) had been enlarged due to substitution of divalent CO32- anions by a larger quantity of monovalent Ac- anions. Differential scanning calorimetry tests testified that the insoluble Mg2/Al-Ac- LDH evidently decreased the freeze point (FP) of water to -10.68°C. X-ray photoelectron spectroscopy analyses confirmed that the Ac- were strongly confined by the metal layers of LDHs. FP test of asphalt mixtures confirmed that Mg/Al-Ac- LDHs reduced FP to -5.5°C. Immersion test results indicated that Mg/Al-Ac- LDH had a good deicing durability and Ac- did not released from asphalt mixture. Snow melting observation was conducted further testified that Mg/Al-Ac- LDH melted snow or ice sustainably.

PASPA: a web server for mRNA poly(A) site predictions in plants and algae.

MOTIVATION: Polyadenylation is an essential process during eukaryotic gene expression. Prediction of poly(A) sites helps to define the 3' end of genes, which is important for gene annotation and elucidating gene regulation mechanisms. However, due to limited knowledge of poly(A) signals, it is still challenging to predict poly(A) sites in plants and algae. PASPA is a web server for P: oly( A: ) S: ite prediction in P: lants and A: lgae, which integrates many in-house tools as add-ons to facilitate poly(A) site prediction, visualization and mining. This server can predict poly(A) sites for ten species, including seven previously poly(A) signal non-characterized species, with sensitivity and specificity in a range between 0.80 and 0.95.

VAAPA: a web platform for visualization and analysis of alternative polyadenylation.

Polyadenylation [poly(A)] is an essential process during the maturation of most mRNAs in eukaryotes. Alternative polyadenylation (APA) as an important layer of gene expression regulation has been increasingly recognized in various species. Here, a web platform for visualization and analysis of alternative polyadenylation (VAAPA) was developed. This platform can visualize the distribution of poly(A) sites and poly(A) clusters of a gene or a section of a chromosome. It can also highlight genes with switched APA sites among different conditions. VAAPA is an easy-to-use web-based tool that provides functions of poly(A) site query, data uploading, downloading, and APA sites visualization. It was designed in a multi-tier architecture and developed based on Smart GWT (Google Web Toolkit) using Java as the development language. VAAPA will be a valuable addition to the community for the comprehensive study of APA, not only by making the high quality poly(A) site data more accessible, but also by providing users with numerous valuable functions for poly(A) site analysis and visualization.

Comparison of fasting capillary glucose variability between insulin glargine and NPH.

The aim of this study was to compare coefficient of variation of fasting capillary blood glucose (FBG) between insulin glargine and NPH in T2DM with poorly controlled by oral antidiabetic drugs. The results demonstrated that insulin glargine was more potent in improving glycemic control than NPH with stable FBG.

[Effects of leptin on RAAS and nitric oxide production in isolated rat glomeruli].

OBJECTIVE: To investigate the changes in angiotensinogen (AGT), angiotensin II type 1 receptor (AT(1)R), endothelial nitric oxide synthase (eNOS) mRNA and protein expressions and nitric oxide (NO) content in the rat glomeruli in response to leptin stimulation. METHODS: The glomeruli isolated from male SD rats were stimulated with 3 nmol/L leptin for 2 h. Real-time PCR and Western blotting were performed to analyze the mRNA and protein expressions of AGT, AT(1)R and eNOS in the glomeruli, and nitrite concentration in the glomeruli was measured by nitrate reductase assay. RESULTS: In comparison with the control group, exposure to leptin increased the mRNA levels of AGT, ATR(1) and eNOS in the isolated glomeruli by 2.69-/+0.17, 3.77-/+0.16 and 2.56-/+0.29 folds (P=0.024, 0.018 and 0.044), and their protein levels by 2.06-/+0.10, 2.67-/+0.08 and 1.61-/+0.13 folds (P=0.021, 0.015 and 0.032), respectively. The NO production in the glomeruli was also increased by 2.77-/+0.14 folds (P=0.000) following leptin exposure. CONCLUSION: Leptin exposure of isolated rat glomeruli directly causes activation of the internal renal renin-angiotensin system and enhanced NO production, suggesting that leptin plays a role in the pathogenesis of maladaptation in renal hemodynamics in obesity.

[Effects of quercetin and enalapril on amount of PDGF-B and VEGF-1 in kidney of diabetic rats].

This study sought to assess the effects of Quercetin and Enalapril on urinary protein excretion and amount of platelet-derived growth factor-B (PDGF-B) and vascular endothelial growth factor-1 (VEGF-1) in renal tissue of diabetic rats. 29 streptozotocin-induced diabetic rats were divided into 3 groups, diabetic control group (group D, n=12); Enalapril group (group E, n=10); Quercetin group (group Q, n=7). In addition, there was one normal control group (group N, n = 5). The urinary protein excretion of 24 hours was measured at 4, 8, 12 weeks. All rats were sacrificed at 12 weeks. The amounts of PDGF-B and VEGF-1 in renal tissue were measured by immunohistochemical techniques. The 24-h levels of urinary protein excretion of D,Q and E groups were higher than that of N group; the level of Q, E groups were lower than that of D group; there was no difference between Q and E group. The expression levels of PDGF-B and VEGF-1 in renal tissue of D, Q, and E groups were significantly higher than that of N group the levels of Q and E groups were significantly lower than that of D group, no difference was found between Q and E group. The protective role of Quercetin and Enalapril in lowering urinary protein excretion may be related to the decreased amounts of PDGF-B and VEGF-1 in renal tissue.