Treatment of industrial wastewater containing Congo Red and Naphthol Green B using low-cost adsorbent

The present work investigates the potential use of metal hydroxides sludge (MHS) generated from hot dipping galvanizing plant for adsorption of Congo Red and Naphthol Green B dyes from aqueous solutions. Characterization of MHS included infrared and X-ray fluorescence analysis. The effect of shaking time, initial dye concentration, temperature, adsorbent dosage and pH has been investigated. The results of adsorption experiments indicate that the maximum capacity of Congo Red and Naphthol Green B dyes at equilibrium (q _e) and percentage of removal at pH 6 are 40 mg/g, 93 %, and 10 mg/g, 52 %, respectively. Some kinetic models were used to illustrate the adsorption process of Congo Red and Naphthol Green B dyes using MHS waste. Thermodynamic parameters such as (ΔG, ΔS, and ΔH) were also determined.     

Aging-independent and size-dependent genotoxic response induced by titanium dioxide nanoparticles in mammalian cells

Titanium dioxide nanoparticles(TiO_2 NPs) are subjected to various transformation processes(chemical, physical and biological processes) in the environment, potentially affecting their bioavailability and toxic properties. However, the size variation of TiO_2 NPs during aging process and subsequent effects in mammalian cells are largely unknown. The aim of this study was to illustrate the adverse effects of TiO_2 NPs in different sizes(5, 15 and 100 nm) during aging process on human-hamster hybrid(A_L) cells. There was an aging-time dependent enhancement of average hydrodynamic size in TiO_2 NPs stock suspensions. The cytotoxicity of fresh TiO_2 NPs increased in a size-dependent manner; in contrast, their genotoxicity decreased with the increasing sizes of NPs. No significant toxicity difference was observed in cells exposed to either fresh or 60 day-aged TiO_2 NPs. Both Fresh and aged TiO_2 NPs efficiently induced mitochondrial dysfunction and activated Caspase-3/7 in a size-dependent manner.Using mitochondrial-DNA deficient(ρ~0) ALcells, we further discovered that mitochondrial dysfunction made significant contribution to the size-dependent toxicity induced by TiO_2 NPs during the aging process. Taken together, our data indicated that TiO_2 NPs could significantly induced the cytotoxicity and genotoxicity in an aging time-independent and size-dependent manner, which were triggered by mitochondrial dysfunction. Our study suggested the necessity to include size as an additional parameter for the cautious monitoring of TiO_2 NPs disposal before entering the environment.     

基于测试数据的室内超宽带信道建模研究

基于室内超宽带信道测量研究建立了基于簇的时延抽头模型以及与距离和载频有关的新颖的路径损耗模型,建立了路径损耗同时与距离和频率的依赖关系.同时,研究发现视距和非视距接收信号幅度分别满足莱斯和瑞利分布.该模型对超宽带无线系统仿真和设计有重要的指导意义.     

Purification and biochemical characterization of recombinant alcohol dehydrogenase from the psychrophilic bacterium <Emphasis Type="Italic">Pseudomonas</Emphasis><Emphasis Type="Italic">frederiksbergensis</Emphasis>

A gram-negative psychrophilic bacterium, with potential for biodegradation of long-chain n-alkanes was isolated from ice samples collected in Spitzbergen, Denmark. On the basis of results of biochemical and morphological tests and sequence analysis of 16S rRNA, the strain was identified as Pseudomonas frederiksbergensis. In this work, a short-chain NAD⁺-dependent alcohol dehydrogenase (alcDH) (Accession number: AAR13804) from the P. frederiksbergensis was cloned and transformed in E. coli BL21 (3DE) competent cells. The alcDH activity was highest in the crude extract of cells induced with 1.0 mM IPTG. The recombinant alcDH enzyme was purified to 93.4% homogeneity using three consecutive purification steps including ammonium sulphate, Q-Sepharose Fast Flow column and gel filtration chromatography employing Superdex 200 10/30 HR column. Enzyme enrichment and yield levels of 31.4 folds and 25.5%, respectively, were achieved. While the subunit molecular mass of the enzyme was determined on SDS-PAGE to be ~38 kDa, the aggregated native form of the enzyme had a molecular mass of ~238 kDa by gel filtration analysis. Reaction conditions optima for the recombinant alcDH were determined with propan-1-ol as the substrate. While the optimum pH was 9, the optimum temperature was 35 °C. The alcDH enzyme exhibited moderate thermal stability with half-lives of 150 min at 55 °C, 27 min at 65 °C and 8 min at 75 °C. Results for kinetic parameters indicated that the apparent K _m value for alcDH with propan-1-ol as the substrate was found to be 1.42 mM and the V _max value was 0.63 mmol mg⁻¹ min⁻¹. Experimental evidence revealed that the recombinant alcDH exhibited a wide range of substrate specificity, with higher levels of specific activity for aliphatic alcohols as compared to secondary alcohols. Taken together, the present study highlights the potential of alcDH as a member of cold-adapted enzymes in several key biotechnological applications including environmental bioremediation and biotransformations. It is envisaged that, with the ongoing screening of microorganisms and metagenomes, directed evolution approaches and the subsequent overexpression of recombinant proteins, more enzymes will be found that are suitable for bioremediation purposes.     

Dual Function of Cellulose Triacetate–Graft–Polymethacrylic Acid Films for Dyes Removal and for High-Dose Radiation Dosimetry

Graft copolymerization of methacrylic acid (MAc) onto cellulose triacetate (CTA) films was conducted by gamma rays. The grafting conditions were optimized. The structure of grafted CTA films was characterized by Fourier transform infra red–attenuated total reflection, scanning electron microscopy, thermal gravimetric analysis, CHNS/O microanalyzer and, surface area and porosity analyzer. The grafted CTA films were exploited in adsorption of ethyl violet (EV) and phenol red (PR) dyes. The adsorption capacity of the grafted CTA films was investigated at various variables. The adsorption isotherms and kinetic study were examined. Further, the dyed grafted CTA films were used in measurements of high dose radiation. The results indicate that the useful dose range extents up to 440 and 300 kGy for EV and PR, respectively. The effects of relative humidity during irradiation, shelf-life, pre- and post-irradiation storage in dark and indirect daylight conditions on dosimeters performance were investigated.     

Hybrid-based Bayesian algorithm and hydrologic indices for flash flood vulnerability assessment in coastal regions: machine learning,risk prediction,and environmental impact

Environmental Science and Pollution Research - Natural hazards and severe weather events are a matter of serious threat to humans, economic activities, and the environment. Flash floods are one of...     

Solomon versus selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome: A systematic review and meta-analysis

This meta-analysis aims to compare the perinatal outcome of twin-twin transfusion syndrome (TTTS) pregnancies undergoing selective versus vascular equator (Solomon) fetoscopic laser photocoagulation (FLP). We performed a systematic search in PubMed and Web of Science from inception up to 25 July 2021. Studies comparing the Solomon and selective techniques of FLP for treatment of TTTS pregnancies were eligible. Random-effects or fixed-effect models were used to pool standardized mean differences (SMD) and log odds ratio. Seven studies with a total of 1664 TTTS pregnancies (n = 671 undergoing Solomon and n = 993 selective techniques) were included. As compared to the selective FLP, Solomon was associated with a lower risk of recurrent TTTS compared to the selective technique (Log odds ratio [OR]: −1.167; 95% credible interval [CrI]: −2.01, −0.33; p = 0.021; I²: 67%). In addition, Solomon was significantly associated with a higher risk of placental abruption than the selective technique (Log [OR]: 1.44; 95% CrI: 0.45, 2.47; p = 0.012; I²: 0.0%). Furthermore, a trend for the higher risk of preterm premature rupture of membranes was observed among those undergoing Solomon (Log [OR]: 0.581; 95% CrI: −0.43, 1.49; p = 0.131; I²: 17%). As compared to selective FLP, the Solomon technique for TTTS pregnancies is associated with a significantly lower recurrence of TTTS; however, it significantly increases the risk of placental abruption.     

Correction to: Multifaceted role of natural sources for COVID-19 pandemic as marine drugs

Environmental Science and Pollution Research -