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Результаты 4511-4520 из 7,292
Synergistic effects of glyphosate- and 2,4-D-based pesticides mixtures on Rhinella arenarum larvae Полный текст
2022
Peluso, Julieta | Furió Lanuza, Agustina | Pérez Coll, Cristina S. | Aronzon, Carolina M.
Glyphosate and 2,4-D are two herbicides commonly used together. Since there is little information about the interactions between these pesticides, the aim of this study was to evaluate the single and joint lethal toxicity of the glyphosate-based herbicide (GBH) ATANOR® (43.8% of glyphosate, isopropylamine salt) and the 2,4-D-based herbicide (2,4-DBH) Así Max 50® (602000 mg/L of 2,4-D) on Rhinella arenarum larvae. Equitoxic and non-equitoxic mixtures were prepared according to the recommendation for their combination and analyzed with a fixed ratio design at different exposure times and levels of lethality (LC10, LC50, and LC90). GBH (504h-LC50=38.67 mg ae/L) was significantly more toxic than 2,4-DBH (504h-LC50=250.31 mg ae/L) and their toxicity was time-dependent. At 48h, the equitoxic mixture toxicity was additive and from the 96h was antagonistic at LC10 and LC50 effect level. The non-equitoxic mixture toxicity was additive at LC10 effect level from the 48h to the 168h, and synergistic from the 240h. At LC50 and LC90 effect level, the mixture interaction resulted synergistic for all exposure times. This is the first study to report the synergistic interactions between GBH and 2,4-DBH on amphibians, alerting about its negative impact on aquatic ecosystems.
Показать больше [+] Меньше [-]Identification and characterization of eight metallothionein genes involved in heavy metal tolerance from the ectomycorrhizal fungus Laccaria bicolor Полный текст
2022
Liu, Binhao | Dong, Pengcheng | Zhang, Xinzhe | Feng, Zhihang | Wen, Zhugui | Shi, Liang | Xia, Yan | Chen, Chen | Shen, Zhenguo | Lian, Chunlan | Chen, Yahua
Metallothioneins (MTs) are small, cysteine-rich, heavy metal-binding proteins involved in metal homeostasis and detoxification. The increasing numbers of available genomic sequences of ectomycorrhizal (ECM) fungi enable deeper insights into the characteristics of MT genes in these fungi that form the most important symbiosis with the host trees in forest ecosystems. The aim of this study was to establish a comprehensive, genome-wide inventory of MT genes from the ECM fungus Laccaria bicolor. Eight MT genes in L. bicolor were cloned, and the expression patterns of their transcripts at various developmental stages based on expressed sequence tag (EST) counts were analyzed. The expression levels of four MTs were significantly increased during symbiosis stages. Quantitative real-time PCR (qRT-PCR) analysis revealed that transcripts of LbMT1 were dominant in free-living mycelia and strongly induced by excessive copper (Cu), cadmium (Cd), and hydrogen peroxide (H₂O₂). To determine whether these eight MTs functioned as metal chelators, we expressed them in the Cu- and Cd-sensitive yeast mutants, cup1∆ and yap1∆, respectively. All LbMT proteins provided similar levels of Cu(II) or Cd(II) tolerance, but did not affect by H₂O₂. Our findings provide novel data on the evolution and diversification of fungal MT gene duplicates, a valuable resource for understanding the vast array of biological processes in which these proteins are involved.
Показать больше [+] Меньше [-]Effect of temperature on PTEs deportment and ecological risks of the biochars obtained from sewage sludge Полный текст
2022
Kong, Lulu | Zhang, Xuhu | Wang, Xinyou | Han, Ming | Shan, Qiang | Jin, Changlin | Tian, Xizhao
Sewage sludge-derived biochars (SSBCs) were obtained at temperatures of 300, 500, and 700 °C to investigate the potentially toxic elements (PTEs) behaviors and assess the environmental acceptability for the possible application in the environment. Results indicated that PTEs exhibited diversely in the distribution of chemical speciation, while all elements tended to be immobilized in biochar matrix and the total amount elevated during the pyrolysis. The risk assessment of biochars implied a low degree of environmental risk for the utilization of SSBCs prepared at high temperatures. In addition, higher pyrolysis temperature alleviated the inhibition on the early seedling growth of Triticum aestivum L., with root elongation more sensitive to the biochar addition. PTEs, especially Cr, contributed much to the phytotoxicity of biochars as revealed by the principle component analysis (PCA) and leaner correlation analysis. Findings from this work illustrated that SSBCs prepared at higher temperatures might be more conductive to a wide range of applications with acceptable environmental risk.
Показать больше [+] Меньше [-]Effect of infection control training course on knowledge and practices of medical interns in a large academic hospital in Egypt: an intervention study Полный текст
2022
El Sebaey, Aya Farag | Atlam, Samir Abd El Mageed | El Kafas, El Sayed Abd El Rahman | Zayed, Hanaa Abdelaziz
Health care-associated infections are reported among the top causes of hospital deaths worldwide. Their prevention is a first priority for patient safety in acute care hospitals. Education and training is recommended as a core component for effective infection prevention and control programs. This study aimed to assess the effect of an infection control training course on the knowledge and practices of medical interns in a large academic hospital in Egypt. The study included 268 medical interns who were getting their practical training at Tanta University Hospitals, Egypt during the study period. Knowledge and practices regarding infection control measures were assessed using a predesigned questionnaire sheet and an observational checklist before and after intervention by infection control training course based on Egyptian national guide for infection control. The data have been analyzed through the application of descriptive frequency, percentages, mean of scores, and the inferential analysis that includes paired t test and Monte Carlo test. The level of statistical significance was adopted at p≤0.05. There was a statistically significant (p < 0.0001) increase in total knowledge score (65.4±13.9 versus 80.2 ±13.2) and total practices score (65±11.3 versus 108±7.9) of infection control measures among studied participants before intervention compared with after intervention. A significant strong positive correlation was detected (r= 0.8, p= 0.0001) between total knowledge and practice scores after intervention by training course. There is a strong positive correlation between knowledge and practices so intervention by infection control training course using teaching multimedia and role play significantly improves the knowledge and practice levels of the studied medical interns.
Показать больше [+] Меньше [-]Association between non-optimal temperature and hospitalizations for gout in Anqing, China: a time-series analysis Полный текст
2022
He, Yi-Sheng | Wang, Gui-Hong | Wu, Zheng-Dong | Sam, Napoleon Bellua | Chen, Yue | Tao, Jin-Hui | Fang, Xin-Yu | Xu, Zhiwei | Pan, Hai-Feng
Previous studies have found that non-optimal temperature influences the development of gout, but the results have been inconsistent. The present study aimed to explore the effects of high temperature and high temperature variation on hospitalizations for gout in Anqing, China. We collected daily data on air pollutants, meteorological factors, and hospitalizations for gout between 1January 2016 and 31 December 2020 in Anqing City, China. We used Poisson generalized linear regression model and a distributed lag non-linear model (DLNM) to explore the relationship of high temperature, diurnal temperature range (DTR), and temperature change between neighboring days (TCN) with hospitalizations for gout. Stratified analysis by gender (male, female) and age (<65 years, ≥65 years) was conducted. Hospitalizations for gout attributed to high temperature, high DTR, and high TCN were also quantified. A total of 8675 hospitalized patients with gout were reported during the study period. We observed that exposure to high temperature was linked with an increased risk of hospitalizations for gout (lag 0, RR: 1.081, 95% confidence interval (CI): 1.011, 1.155). Exposure to high DTR was also associated with increased risk of hospitalizations for gout (lag9, RR: 1.017, 95% CI: 1.001,1.035). A large drop in temperature between neighboring days was associated an increased risk of hospitalizations for gout (lag 0–2 days, RR: 1.234, 95% CI: 1.017, 1.493). Stratified analysis results revealed that older adults and men were more sensitive to high-level DTR exposure than their counterparts. Nearly 15% of hospitalizations for gout could be attributable to high temperature (attributable fraction: 14.93%, 95% CI: 5.99%, 22.11%). This study suggests that high temperature and high temperature variation may trigger hospitalizations for gout, indicating that patients with gout need to take proactive actions in the face of days with non-optimal temperature.
Показать больше [+] Меньше [-]Synthesis of Ag/BiOBr/CeO2 composites with enhanced photocatalytic degradation for sulfisoxazole Полный текст
2022
Wang, Yaqiao | Xia, Xunfeng | Gao, Shengwang | Zhao, Xingpeng | Wang, Guoying | Han, Xue
A novel Ag/BiOBr/CeO₂ composite was successfully prepared for the first time, which had excellent performance in degrading sulfisoxazole (SSX) under visible light irradiation. The as-prepared samples were characterized by SEM, XRD, UV–vis DRS and BET et al. The composite of 10% Ag/BiOBr/CeO₂ showed the best photocatalytic activity and more than 99.5% SSX can be removed within 20 min. It exhibited the highest k value of 0.2428 min⁻¹, which was about 39.7 times higher than pure BiOBr (6.11 × 10⁻³ min⁻¹) and 22.1 times higher than BiOBr/CeO₂ (1.09 × 10⁻² min⁻¹), respectively. The addition of Ag significantly improved the absorption rate of visible light and the separation rate of photogenerated electron–hole pairs. The initial pH and dosage of samples could have an influence on the photocatalytic activity. The radical trapping experiments proved that ·O₂⁻ and h⁺ were the main active species involved in photocatalytic degradation. Finally, the synthesized catalyst maintained excellent photocatalytic activity after 5 repeated cycles, which indicated the extraordinary stability and recyclability of Ag/BiOBr/CeO₂.
Показать больше [+] Меньше [-]Effect of the green synthesized rGO and Mg/rGO nanocomposites on the phytochemical assay, toxicity, and metabolism of Mentha longifolia in vitro cultures Полный текст
2022
Jafarirad, Saeed | Kosari‑Nasab, Morteza | Aminpour, Monireh | Rezaei, Zahra
Reduced graphene oxide (rGO) and Mg/rGO nanocomposites (NCs) were prepared by an eco-friendly technique using Rosa canina fruit extract. Physicochemical properties and cytotoxicity to Mentha longifolia in vitro cultures of these nanomaterials were examined by using XRD, FESEM, EDX, FT-IR, DLS/zeta potential, UV–Visible, and GC–MS techniques. The characterization techniques confirmed the synthesis of rGO and Mg/rGO NCs with particle sizes less than 20 nm (based on FESEM). In accordance to the biological measurements, rGO showed in vitro cytotoxicity to M. longifolia shoot cultures. Mg/rGO NCs showed no significant difference in the growth parameters except for a decrease in the shoot number at the concentrations of 50 and 150 mg/L and a decrease in the length of the tallest root at the concentrations of 100 and 150 mg/L, however efficiently improved the photosynthetic pigment contents. The phytochemical assay depicted that the total content of volatile compounds was increased in the treated cultures with 25, 50, and 100 mg/L of rGO and Mg/rGO NCs in comparison to the control. Generally, the more oxygenated and hydrocarbon sesquiterpenes were observed in the cultures treated with 25 and 100 mg/L of rGO and 25 and 50 mg/L of Mg/rGO NCs.
Показать больше [+] Меньше [-]Recovery of phosphate as hydroxyapatite by fluidized bed homogeneous crystallization technique Полный текст
2022
Divya, Kandethupara Bhaskaran | Ramesh, Srikrishnaperumal Thanga | Lavanya, Addagada | Gandhimathi, Rajan
Phosphorous recovery from aqueous solutions gained substantial attention and this not only secure the food demand but also curtail the pollution of freshwater courses. In the current study, authors employed novel fluidized bed homogeneous crystallization (FBHC) technique to granulate the phosphorous as hydroxyapatite (HAP). FBHC technique nurtures the formation of high pure HAP crystals without seed addition and potential technique to recover phosphorous compared to other techniques. The key operational parameters influencing the HAP crystallization were analyzed prior to FBHC by batch analysis. From the batch study results, the range of pH and calcium to phosphorous molar ratio fixed for FBHC studies. Maximum phosphate removal and granulation efficiencies obtained were 91.25% and 82.55%, respectively, at 500 mg/L phosphate concentration, pH 12, and calcium to phosphorous molar ratio 1.65. Box-Behnken design of response surface methodology was employed for evaluating interaction impact of process parameters on granulation efficiency. Granulation efficiency of 79.74% was attained at pH 11.83, calcium to phosphorous molar ratio 1.637, and reaction time 70.73 h.
Показать больше [+] Меньше [-]New biopolymer from biomass for conditioning and dehydration of sewage sludge: application on the sludge of Bouira WWTP Полный текст
2022
Kebaili, Maya | Djellali, Souad | Drouiche, Nadjib | Lounici, Hakim
Sewage treatment plants in Algeria produce huge quantities of sludge expressed in tons annually. This sludge produced is unfortunately contaminated because of the use of synthetic polyelectrolytes. Recently several kinds of research have been carried out on natural flocculants for sludge conditioning, because of several advantages they present such as their renewable source and their non-toxicity. This work aims to evaluate the potential use of protonated pectin extracted from orange waste of N’GAOUS juice factory as an eco-friendly flocculant in the chemical conditioning of sludge. Protonated pectin effectiveness was compared with synthetic cationic anionic and ionic polyelectrolytes (SUPERFLOC 8396, AF400, NF102). In this context, raw sludge samples from Bouira WWTP were tested. Specific resistance to filtration (SRF), cakes dry solid content were analyzed to determine filterability, dewatering capacity of conditioned sludge, and the optimum dose of each conditioner. So that our goal was to obtain greater dryness, which is the case with the addition of protonated pectin and even the addition of Superfloc, which allowed us to obtain dryness of 33.01% and 29.19%, respectively, for the same doses that gave the lowest SRF. Based on the results found and the analysis of the specific resistance to filtration (SRF) and the dryness, and compared with the values observed for the dewatered sludge by the method used in the Bouira WWTP. Band filters (18–22%) and raw sludge (4.8–5.7%).
Показать больше [+] Меньше [-]Bio-cement-modified construction materials and their performances Полный текст
2022
Yu, Xiaoniu | He, Zhihai | Li, Xianyan
The microbial induced mineral precipitation can be used to modify and improve the performance of construction materials and can partially replace ordinary Portland cement. Microbially induced carbonate precipitation (MICP) mainly uses the urease secreted during the growth of urease-producing bacteria (UPB) to hydrolyze urea produce CO₃²⁻ and reacts with Ca²⁺ to form CaCO₃. Microbially induced struvite precipitation (MISP) mainly uses the urease to decompose urea to produce NH₄⁺. In the presence of hydrogen phosphate and magnesium ions, the struvite can be precipitated. The elemental composition and chemical composition of the precipitates produced by the MICP and MISP processes are analyzed by energy dispersive X-ray spectroscopy (EDS) and powder X-ray diffraction analysis (XRD). The morphology of the precipitates can be observed by scanning electron microscope (SEM). Compared with the initial porosity, the MICP method can reduce the initial porosity of the sand column by 2.98% within 90 min. However, the MISP is only 1.45%. The permeability coefficient of the sand column can be effectively reduced in the MICP process. The total content of cementitious materials is 27.71g and 13.16g in MICP- and MISP-cemented sand columns, respectively. The MICP technology can improve the strength of alkali-activated mortars under different pH values of the UPB solution.
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