Preparation of 3D flexible SERS substrates by mixing gold nanorods in hydrogels for the detection of malachite green and crystal violet.

A simple and cost-effective fabrication method of gold nanorods (AuNRs) nanoparticles hybridized with polyvinyl alcohol hydrogel (AuNR/PVA) for SERS substrate is described. The AuNR/PVA achieves the control of inter-particle nanogap by modulating the density of gold nanorods, and inter-particle nanogap by the spatial deformation of the hydrogel, and the reduction of the gap between the AuNRs deposited on hydrogel makes the SERS enhancement. In addition, the AuNR/PVA substrate maintains high SERS activity after more than 100 cycles of bending and storage in air for 30 days, and the substrate possesses high sensitivity and high reproducibility. Combining a flexible and transparent surface-enhanced Raman spectroscopy (SERS) substrate for in situ detection with a small portable Raman can be applied to scenarios such as environmental detection and hazardous materials detection. The substrate showed excellent SERS activity against malachite green (MG) and crystal violet (CV) with limits of detection of 1.18 × 10-13 M and 7.17 × 10-12 M, respectively. The usability of the proposed SERS substrate was demonstrated by detecting the above contaminants in aquatic water. This work not only utilizes a cost-effective method for mass production but also provides a reliable and convenient platform for the preparation of other noble metal flexible substrates.

Environmental carrying capacity and ecological risk assessment of pesticides under different soil use types in the Central Plains Urban Agglomeration (CPUA), China.

Soil environmental safety has received much attention during the past few decades due to its significance in agricultural production and human health. Special attention is required for soil pesticide residues and ecological risks. This study examined 197 soil samples from industrial, residential and agricultural areas for the presence of 12 organophosphorus pesticides (OPPs) and 8 synthetic pyrethroids (SYPs) in the 16 cities in Henan Province, and the center of CPUA, based on the Central Plains Urban Agglomeration (CPUA) concept proposed by China. The total average concentrations of ∑12OPPs in industrial, residential and agricultural soils were 194, 217, 267 ng/g dry weight, and those of ∑8SYPs were 26.8, 35.7, 25.5 ng/g dry weight, respectively. The two pollutants with the greatest concentrations in the soils were malathion and fenpropathrin, respectively, the dominant components of OPPs and SYPs. The soil environmental carrying capacity (SECC) analysis, representing the maximum residual load that can be supported, shows that acephate and cyhalothrin were overloaded, with a predicted period of over 500 years. Among the 16 cities of CPUA, a higher frequency of high ecological risk could be observed only in Shangqiu. The OPPs in children had total non-carcinogenic risk values of more than 1.0. Similarly, the non-carcinogenic risks of SYPs in adults and children in the residential areas were more than 1.0. The study provides knowledge on how to effectively manage soil safety in Henan Province, which is the center of the CPUA, with a large population and grain province to protect ecosystems and reduce the risks of soil pesticide residues in humans.

The effect of dual-task training on cognitive ability, physical function, and dual-task performance in people with dementia or mild cognitive impairment: A systematic review and meta-analysis.

OBJECTIVE: To summarize the effect of dual-task training on cognitive, physical function, and dual-task performance in people with mild cognitive impairment or dementia. DATA SOURCES: Embase, PEDro, PsycINFO, PubMed, CINAHL, The Cochrane Library, and a forward search conducted via Web of Science have been searched from inception to July 2023. REVIEW METHODS: Good-quality randomized controlled trials compared dual-task training with no/placebo intervention or single-task training among people with a primary diagnosis of mild cognitive impairment or dementia were included. The PEDro scale was used to evaluate the methodological quality of individual studies. The Grading of Recommendations, Assessment, Development and Evaluations system was adopted to appraise the quality of evidence for each outcome. RESULTS: Eighteen trials (1325 participants) were included, and 17 provided data for meta-analysis. Comparing with no intervention, dual-task training led to significant improvements on attention (mean difference (MD) = -20.66, 95%CI [-39.42, -1.90]), functional mobility (MD = -2.73; 95%CI [-3.98, -1.49]). Compared with single-task training, dual-task training had greater effects on overall cognitive function (standardized mean difference (SMD) = 0.29, 95%CI [0.09, 0.49]), balance (SMD = 0.78, 95%CI [0.40, 1.15]) and functional mobility (MD = -1.17; 95%CI [-1.77, -0.58]). Its effect on dual-task performance remains inconclusive due to the inconsistent results reported. CONCLUSION: Low- to moderate-quality evidence supports that dual-task training has beneficial effects on cognitive function and physical function in individuals with dementia or mild cognitive impairment. The optimal training protocol of dual-task training on cognitive and physical functions, and dual-task performance remains uncertain. Well-designed, randomized studies with large enough sample sizes are warranted.

An indirect competitive assay-based method for the sensitive determination of tetracycline residue using a real-time fluorescence-based quantitative polymerase chain reaction.

Tetracycline (TC) is an effective antibiotic used to treat humans and livestock, but its inappropriate use imposes toxic effects, including pollution, on environmental ecology and food. Currently, sensitive, accurate, and cost-effective methods that can detect lower concentrations of TC residues in environmental and food samples are needed. In this study, a novel indirect competitive assay-based aptamer method was developed for detecting TC residues through signal amplification by real-time fluorescence-based quantitative polymerase chain reaction. The response surface methodology was introduced to optimize the optimal concentrations (influencing factors) of the three types of single-stranded DNA in the competitive assay process. The optimal conditions for the three types of ssDNA were 112 nM for the specific aptamer of TC (Apt40), 115 nM for the signal DNA, and 83 nM for the DNA catcher. As expected, under optimal conditions, the Ct value was linearly related to the logarithm of TC concentration. The calibration curve equation was Ct = -0.34516 log[TC] + 9.9345 (R2 = 0.998) in the range of 10-3-103 ng mL-1, and the limit of detection was 7.02 × 10-5 ng mL-1. The new method was effectively applied to detect TC residues in wastewater, honey, and milk samples. It achieved an average recovery rate of 101.19% with a small variation of 5.16%. The validation was carried out using an enzyme-linked immunosorbent assay. This approach demonstrates high sensitivity and selectivity, making it well suited for detecting leftover antibiotics in food when using suitable aptamers.

Heavy metals pollution of soil in central plains urban agglomeration (CPUA), China: human health risk assessment based on Monte Carlo simulation.

The present study conducted the concentration evaluation, pollution assessment, source analysis, and risk assessment of heavy metals in the soil of the CPUA, China, to contribute to the smooth construction of urban agglomeration. Elevated levels of mean concentrations of cadmium (Cd), chromium (Cr), and copper (Cu) in the soils were shown compared to background values. Cu and zinc (Zn) and also lead (Pb) and Cd exhibited spatial similarity. Manganese (Mn) and Cr exhibited point source characteristics such as the concentrations at a point much higher than the surrounding area. The potential ecological risk in the northern region belonged to the moderate risk level category. Cd contributed over 90% to the potential ecological risk. The health risk among children was higher than that among adults. The major exposure pathways were different for adults and children. Exposure, as shown using Hazard Index (HI), to adults was mainly through the skin contact route, while to children was through both the skin contact and ingestion route. The primary CR (carcinogenic risk) to adults was through the inhalation route, while that to children was through the ingestion route. In both children and adults, Cr was the main contributor to HI and CR. According to the Monte Carlo simulation results, the cumulative probability of exceeding the critical value of HI for children was approximately 2.8-3.0 times that for adults. According to the sensitivity analysis results, non-carcinogenic risk prevention should begin mainly by reducing exposure duration and skin contact. The cancer risk may be reduced primarily by decreasing the exposure duration and controlling ingestion. The PMF (Positive Matrix Factorization) source analysis revealed that Pb mainly came from transportation sources. In addition, Cu, Pb, and Mn were derived mainly from agricultural sources. Cr was derived mostly from a natural source, and Cd originated mainly from an industrial source.

Biodegradation of di(2-ethylhexyl) phthalate by a new bacterial consortium.

Di(2-ethylhexyl) phthalate (DEHP) with continuous high concentration was used as the sole carbon and energy source to isolate a new bacterial consortium (K1) from agricultural soil covered with plastic film for a long time. Unclassified Comamonadaceae, Achromobacter, and Pseudomonas in K1 were identified as major genera of the consortium by high-throughput sequencing, and unclassified Commanadaceae was first reported to be related to DEHP degradation. Response surface method (RSM) showed that the optimum conditions for K1 to degrade DEHP were 31.4 °C, pH 7.3, and a concentration of 420 mg L-1. K1 maintains normal cell viability and stable DEHP degradation efficiency in the range of 10-3000 mg L-1 DEHP concentration, which is superior to existing research. The biodegradation of DEHP followed first-order kinetics when the initial concentration of DEHP was between 100 and 3,000 mg L-1. GC-MS analysis of different treatment groups showed that DEHP was degraded by the consortium group through the de-esterification pathway, and treatment effect was significantly better than that of the single bacteria treatment group. The subsequent substrate utilization experiment further confirmed that K1 could quickly mineralize DEHP. In addition, K1 has high degradation capacity for the most common phthalate acid esters in the environment.

Bacterial cellulose loaded with silver nanoparticles as a flexible, stable and sensitive SERS-active substrate for detection of the shellfish toxin DTX-1.

Diarrheal shellfish toxins are considered one of the most lethal red tide algae toxins in the worldwide. In this work, we propose an Ag NPs-loaded bacterial cellulose membrane (BCM) surface-enhanced Raman scattering (SERS) sensor based on an aptamer (Apt) for the ultrasensitive detection of dinophysistoxin (DTX-1), a type of diarrheal shellfish toxin. During drying, Ag NPs can be further densified on "gel-like" BCM to form high-density SERS "hot spots". We developed the "Apt-SH@Ag NPs@BCM" SERS sensor and used the competition of DTX-1 and complementary base (Cob) in the process of base complementary pairing to achieve SERS detection of DTX-1, with a minimum detection limit of 9.5 × 10-10 mol/L. Sample assays showed DTX-1 recovery rates ranging from 95.8% and 108.2% and the detection results were comparable to those obtained by LC-MS. Therefore, this work holds great potential for detecting of toxic substances in shellfish products, especially for the oyster (portuguese oyster) and mussel (blue mussel).

Enhanced degradation of phthalate esters (PAEs) by biochar-sodium alginate immobilised Rhodococcus sp. KLW-1.

In this study, a new strain of bacteria, named Rhodococcus sp. KLW-1, was isolated from farmland soil contaminated by plastic mulch for more than 30 years. To improve the application performance of free bacteria and find more ways to use waste biochar, KLW-1 was immobilised on waste biochar by sodium alginate embedding method to prepare immobilised pellet. Response Surface Method (RSM) predicted that under optimal conditions (3% sodium alginate, 2% biochar and 4% CaCl2), di (2-ethylhexyl) phthalate (DEHP) degradation efficiency of 90.48% can be achieved. Under the adverse environmental conditions of pH 5 and 9, immobilisation increased the degradation efficiency of 100 mg/L DEHP by 16.42% and 11.48% respectively, and under the high-stress condition of 500 mg/L DEHP concentration, immobilisation increased the degradation efficiency from 71.52% to 91.56%, making the immobilised pellets have strong stability and impact load resistance to environmental stress. In addition, immobilisation also enhanced the degradation efficiency of several phthalate esters (PAEs) widely existing in the environment. After four cycles of utilisation, the immobilised particles maintained stable degradation efficiency for different PAEs. Therefore, immobilised pellets have great application potential for the remediation of the actual environment.

Degradation of tetracycline wastewater by suspended biochar as carriers in moving bed biofilm reactor.

To improve the removal efficiency of antibiotics in moving bed biofilm reactor, suspended biochar block was prepared by the one-pot process and was used as carriers to construct a reaction device to study the treatment effect of antibiotic wastewater. The characteristics of the hanging biofilm in wastewater were investigated. And the mechanism of biochar as a biological carrier has been studied. The results showed that in the 45-day experiment, the maximum number of biofilms for suspended biochar carriers was twice 3.4 times that of the high-density polyethylene carriers. When 10 mg/L tetracycline was added to the reactor, the removal efficiency of the tetracycline removal rate was 71.85% and the chemical oxygen demand (COD), total nitrogen (TN), and NH4+-N removal efficiency reached to 89.95, 61.91 and 85.47% respectively. Suspension biochar carriers can reduce fluctuations in redox potentials, thereby improving the cellular efficiency of microorganisms. Meanwhile, it inhibits the production of soluble microbial products and extracellular polymers, reduces toxic effects, and enhances the adhesion between microorganisms and carriers. The microbial communities of the two carriers were investigated by high-throughput sequencing techniques. Suspended biochar significantly increased the relative abundance of Hydrogenophaga and Comamonas, and improved the ability of nitrification and denitrification. Comamonas could be responsible for tetracycline degradation.

Polycyclic aromatic hydrocarbons in soils of Central Plains Urban Agglomeration, China: The bidirectional effects of urbanization and anthropogenic activities.

To investigate the variations in environmental behavior (levels, distribution, sources, and soil toxicity) of polycyclic aromatic hydrocarbons (PAHs) under the impact of anthropogenic activities during the urbanization process, we collected soil samples from 195 sites in the Central Plains Urban Agglomeration (CPUA), North China, and analyzed 16 U.S. Environmental Protection Agency (EPA) PAH priority pollutants. We divided the sampling sites into three groups (urban area, industrial area, and farmland) and collected soil samples (0-20 cm surface layer). ∑16PAHs concentrations in the soils of the urban area, industrial area, and farmland ranged from 24.2 to 4400 ng/g, 12.3-8780 ng/g, and 20.9-852 ng/g (the average value of 349, 634, and 186 ng/g), respectively. The 4 to 5 ring PAHs were dominant compounds in three soil types, accounting for 65-80% of the ∑16PAHs. The results of the source analysis showed that the PAHs in the soils of CPUA were mainly from energy consumption. PAH levels in urban and industrial soils had a potential low cancer risk. The impact of urbanization on PAHs in the soil was bidirectional. On the one hand, the level of PAHs in the farmland soil might increase due to burning coal and agricultural machinery, which releases diesel or petrol fumes. On the other hand, in the urbanization process, the PAH content in urban soil and industrial soil showed a downward trend due to the implementation of environmental protection policies in China, which have reduced the atmospheric input of PAHs into the soil.

Ultrasensitive detection of PCB77 based on Exonuclease III-powered DNA walking machine.

In view of the urgent need to determine polychlorinated biphenyls (PCBs) in the environment, we report a simple and sensitive electrochemical aptasensor to detect 3,3',4,4'-tetrachlorobiphenyl (PCB77) based on Exonuclease III-powered Deoxyribonucleic Acid (DNA) walking machine using poly (diallyldimethylammonium chloride) (PDDA), which was functionalized hollow porous graphitic carbon nitride/ Ni-Co hollow nanoboxes/ Au-Pd-Pt nanoflowers composite material. Upon the addition of PCB77, the specific binding between PCB77 and the aptamer (Apt) could trigger the Exo III-assisted cyclic amplification process and release unlocking probes to deblock the Swing arm/Blocker duplex. Finally, the hybridized hairpin 3 (HP3), a short oligonucleotide, was left on the electrode via Exo III digestion of hybridized HP2, and thus a strong methylene blue (MB) signal was obtained. As expected, the proposed aptasensor exhibits exceptional PCB77 detection performances with a very low detection limit of 5.13 pg/L and a wide linear range of 0.01-100 ng/L based on the calibration curve. Moreover, the aptasensor presents a high level of selectivity and stability, with an acceptable degree of reproducibility. The results of this study have indicated that the proposed aptasensor has great potential application prospects, as demonstrated by its successful use in real environmental water samples.

The health risk assessment of Heavy Metals (HMs) in road dust based on Monte Carlo simulation and bio-toxicity: a case study in Zhengzhou, China.

Heavy metals (HMs) in road dust pose a significant threat to human health. The analysis of human health risks of HMs is an important theoretical basis for risk screening and management. The chemical forms and characteristics of HMs in road dust were analyzed. Based on the bio-toxicity of the different fractions of the HMs and Monte Carlo, three assessment models, including the health risk assessment based on bio-toxicity, the health risk assessment based on the Monte Carlo simulation, and the health risk assessment based on the Monte Carlo simulation and bio-toxicity, were established. Under the Traditional Model, the non-carcinogenic risks were only harmful to children, while the carcinogenic risks were not harmful to adults and children. Under the M-Traditional Model, the probability of non-carcinogenic risks being harmful to children's health was 83.17%. The probability that carcinogenic risks pose a threat to children's health was 28.61%. Considering the bio-toxicity of HMs in different chemical forms, non-carcinogenic risks and carcinogenic risks under the B-Traditional Model were all less than the corresponding critical values, indicating that the HMs in the road dust did no harm to both the adults and children. Based on the MB-Traditional Model, the chance of non-carcinogenic risks being harmful to children's health is 15.43%. Among different HMs, the non-carcinogenic risks of As are highest and the carcinogenic risks of Cr were the highest, so As and Cr should be listed as priority control contamination. MB-Traditional Model established in this study simultaneously considered bio-toxicity and random simulation and obtained more accurate results, which could provide a theoretical basis for risk analysis and management.

[Assessment model for heavy metal pollution in sediment based on trapezoidal fuzzy numbers and case study].

Due to the practical shortcomings of the classical deterministic pollution assessment model, the theory of trapezoidal fuzzy numbers was introduced to the environmental assessment system. A fuzzy risk assessment model was built based on the geoaccumulation index and biotoxicity coefficients of heavy metals. Using the fuzzy pollution risk assessment model, the risk of heavy metal pollution was evaluated for the surface sediment of Dongting Lake. The results showed that the pollution risk in a descending order was Hg > Cd > Pb > Cu > Cr > Zn > As, with Hg,Cd and Pb being the priority pollutants in Dongting Lake. Both the intervals of possible values for the geoaccumulation indexes of heavy metals and their credible levels were calculated using this model. Compared with the results of the deterministic assessment model, the fuzzy pollution risk assessment model gave a better characetriztaion of the actual pollution status and spatial distribution difference of the heavy metals in the sediment of the studied region which is more objective and comprehensive.

Quantitative evaluation of heavy metals' pollution hazards in liquefaction residues of sewage sludge.

Liquefaction residues (LR) are the main by-products of sewage sludge (SS) liquefaction. This study quantitatively evaluates the potential ecological risk and pollution degrees of heavy metals (Pb, Zn, Cu, Cd, Cr and Ni) in LR versus SS. The leaching rates (R1) of heavy metals in LR were much lower than those in SS, revealing that the mobility/leachability of heavy metals was well suppressed after liquefaction. Geo-accumulation index (Igeo) indicated that the liquefaction process significantly weakened the contamination degrees of heavy metals. Potential ecological risk index (RI) demonstrated that overall risks caused by heavy metals were obviously lowered from 1093.56 (very high risk) in SS to 4.72 and 1.51 (low risk) in LR1 and LR2, respectively. According to the risk assessment code (RAC), each tested heavy metal had no or low risk to the environments after liquefaction. In a word, the pollution hazards of heavy metals in LR were markedly mitigated.

Total concentrations and chemical speciation of heavy metals in liquefaction residues of sewage sludge.

The risk (including bioavailability and eco-toxicity) of heavy metals (Pb, Zn, Cu, Cd, Cr and Ni) in liquefaction residues (LR) of sewage sludge (SS) was estimated, according to both the speciation of heavy metals and the local environmental characteristics. The amount of organic matters in LR was lower than that in SS, resulting in a smaller calorific value, while the total content of heavy metals in LR nearly doubled. High residual rates of heavy metals (about 80%) indicated that the heavy metals in SS were concentrated into LR after liquefaction. The comparisons of sequential extraction results between SS and LR showed that after liquefaction, the mobile and easily available heavy metal fractions (acid soluble/exchangeable and reducible fractions) were mainly transformed into the relatively stable heavy metal fractions (oxidizable and residual fractions). The bioavailability and eco-toxicity of heavy metals in LR were relieved, though the total concentrations of heavy metals increased.