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• This is a polyp segmentation framework with advanced performance on five datasets. • A Multi-scale attention module is designed to extract detail information. • It fuses high-level features and mitigates semantic conflicts. • We construct a module to fuse same-level features and improve decoder. Clinically, automated polyp segmentation techniques have the potential to significantly improve the efficiency and accuracy of medical diagnosis, thereby reducing the risk of colorectal cancer in patients. Unfortunately, existing methods suffer from two significant weaknesses that can impact the accuracy of segmentation. Firstly, features extracted by encoders are not adequately filtered and utilized. Secondly, semantic conflicts and information redundancy caused by feature fusion are not attended to. To overcome these limitations, we propose a novel approach for polyp segmentation, named MLFF-Net, which leverages multi-level feature fusion and attention mechanisms. Specifically, MLFF-Net comprises three modules: Multi-scale Attention Module (MAM), High-level Feature Enhancement Module (HFEM), and Global Attention Module (GAM). Among these, MAM is used to extract multi-scale information and polyp details from the shallow output of the encoder. In HFEM, the deep features of the encoders complement each other by aggregation. Meanwhile, the attention mechanism redistributes the weight of the aggregated features, weakening the conflicting redundant parts and highlighting the information useful to the task. GAM combines features from the encoder and decoder features, as well as computes global dependencies to prevent receptive field locality. Experimental results on five public datasets show that the proposed method not only can segment multiple types of polyps but also has advantages over current state-of-the-art methods in both accuracy and generalization ability. [ABSTRACT FROM AUTHOR]

Background and aims: Phosphate-solubilizing bacteria (PSB) possess significant potential for enhancing soil phosphorus bioavailability, but their efficacy may be constrained by carbon and nitrogen availability. Algae exhibit synergistic interactions with bacteria through producing active organic carbon. However, the influence of algae and PSB together on phosphorus bioavailability under varying nitrogen levels remains unclear.We conducted a microcosm experiment to explore the effects of applying Chlorella-Bacillus biofertilizer, along with various nitrate addition amounts, on both soil microbial community composition and phosphorus bioavailability. In addition, we employed a co-culture of Chlorella and Bacillus with different nitrogen concentrations to investigate the possible effects of nitrate addition on the production of organic anions and phosphatases of the Chlorella-Bacillus communities by using metabolomic analysis.Chlorella-Bacillus biofertilizer significantly increased soil Olsen-P concentration via strong interactive effects correlating with the various nitrate addition amounts in the microcosm experiment. These effects were due mainly to reducing the algal diversity, soil pH, and changing dissolved organic matter (DOM) characteristics, especially increasing the humification index (HIX). The metabolomic analyses of co-culture confirm that pathways related to the biosynthesis of fatty acids and phosphatases production are enhanced when nitrogen levels are high.Chlorella-Bacillus biofertilizer has significantly interactive effects with nitrate addition on soil phosphorus bioavailability by influencing soil DOM, pH and production of organic anions and phosphatases. These insights are useful for optimizing bio-fertilizer-nitrate combinations for increasing phosphorus bioavailability thereby reducing chemical fertilizer requirements.Methods: Phosphate-solubilizing bacteria (PSB) possess significant potential for enhancing soil phosphorus bioavailability, but their efficacy may be constrained by carbon and nitrogen availability. Algae exhibit synergistic interactions with bacteria through producing active organic carbon. However, the influence of algae and PSB together on phosphorus bioavailability under varying nitrogen levels remains unclear.We conducted a microcosm experiment to explore the effects of applying Chlorella-Bacillus biofertilizer, along with various nitrate addition amounts, on both soil microbial community composition and phosphorus bioavailability. In addition, we employed a co-culture of Chlorella and Bacillus with different nitrogen concentrations to investigate the possible effects of nitrate addition on the production of organic anions and phosphatases of the Chlorella-Bacillus communities by using metabolomic analysis.Chlorella-Bacillus biofertilizer significantly increased soil Olsen-P concentration via strong interactive effects correlating with the various nitrate addition amounts in the microcosm experiment. These effects were due mainly to reducing the algal diversity, soil pH, and changing dissolved organic matter (DOM) characteristics, especially increasing the humification index (HIX). The metabolomic analyses of co-culture confirm that pathways related to the biosynthesis of fatty acids and phosphatases production are enhanced when nitrogen levels are high.Chlorella-Bacillus biofertilizer has significantly interactive effects with nitrate addition on soil phosphorus bioavailability by influencing soil DOM, pH and production of organic anions and phosphatases. These insights are useful for optimizing bio-fertilizer-nitrate combinations for increasing phosphorus bioavailability thereby reducing chemical fertilizer requirements.Results: Phosphate-solubilizing bacteria (PSB) possess significant potential for enhancing soil phosphorus bioavailability, but their efficacy may be constrained by carbon and nitrogen availability. Algae exhibit synergistic interactions with bacteria through producing active organic carbon. However, the influence of algae and PSB together on phosphorus bioavailability under varying nitrogen levels remains unclear.We conducted a microcosm experiment to explore the effects of applying Chlorella-Bacillus biofertilizer, along with various nitrate addition amounts, on both soil microbial community composition and phosphorus bioavailability. In addition, we employed a co-culture of Chlorella and Bacillus with different nitrogen concentrations to investigate the possible effects of nitrate addition on the production of organic anions and phosphatases of the Chlorella-Bacillus communities by using metabolomic analysis.Chlorella-Bacillus biofertilizer significantly increased soil Olsen-P concentration via strong interactive effects correlating with the various nitrate addition amounts in the microcosm experiment. These effects were due mainly to reducing the algal diversity, soil pH, and changing dissolved organic matter (DOM) characteristics, especially increasing the humification index (HIX). The metabolomic analyses of co-culture confirm that pathways related to the biosynthesis of fatty acids and phosphatases production are enhanced when nitrogen levels are high.Chlorella-Bacillus biofertilizer has significantly interactive effects with nitrate addition on soil phosphorus bioavailability by influencing soil DOM, pH and production of organic anions and phosphatases. These insights are useful for optimizing bio-fertilizer-nitrate combinations for increasing phosphorus bioavailability thereby reducing chemical fertilizer requirements.Conclusion: Phosphate-solubilizing bacteria (PSB) possess significant potential for enhancing soil phosphorus bioavailability, but their efficacy may be constrained by carbon and nitrogen availability. Algae exhibit synergistic interactions with bacteria through producing active organic carbon. However, the influence of algae and PSB together on phosphorus bioavailability under varying nitrogen levels remains unclear.We conducted a microcosm experiment to explore the effects of applying Chlorella-Bacillus biofertilizer, along with various nitrate addition amounts, on both soil microbial community composition and phosphorus bioavailability. In addition, we employed a co-culture of Chlorella and Bacillus with different nitrogen concentrations to investigate the possible effects of nitrate addition on the production of organic anions and phosphatases of the Chlorella-Bacillus communities by using metabolomic analysis.Chlorella-Bacillus biofertilizer significantly increased soil Olsen-P concentration via strong interactive effects correlating with the various nitrate addition amounts in the microcosm experiment. These effects were due mainly to reducing the algal diversity, soil pH, and changing dissolved organic matter (DOM) characteristics, especially increasing the humification index (HIX). The metabolomic analyses of co-culture confirm that pathways related to the biosynthesis of fatty acids and phosphatases production are enhanced when nitrogen levels are high.Chlorella-Bacillus biofertilizer has significantly interactive effects with nitrate addition on soil phosphorus bioavailability by influencing soil DOM, pH and production of organic anions and phosphatases. These insights are useful for optimizing bio-fertilizer-nitrate combinations for increasing phosphorus bioavailability thereby reducing chemical fertilizer requirements. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Periphyton had sustainable pollutant removal capacity despite toxic effects of TiO 2 -NPs. • Community and metabolism changes are critical in maintaining functional sustainability. • EPS especially protein was overproduced to bind or aggregate NPs to reduce nanotoxicity. • Exposure duration is important for evaluating nanotoxicity on microbial community. Abstract Responses of microbial communities to nanotoxicity in aquatic ecosystems are largely unknown, particularly with respect to relationship between community dynamics and functions. Here, periphytic biofilms were selected as a model of species-rich microbial communities to elucidate their responses when exposed to titanium dioxide nanoparticles (TiO 2 -NPs). Especially, the relationships between the functions (e.g. organic matter and Cu2+ removal) and community dynamics after long-term exposure to TiO 2 -NPs were assessed systematically. After 5 days exposure to TiO 2 -NPs (5 mg L−1), periphytic biofilms showed sustainable functions in pollutant removal and strong plasticity in defensing the toxic disturbance of TiO 2 -NPs, including photosynthesis and carbon metabolic diversity. The sustainable pollutant removal functions of periphytic biofilms were attributed to their functional redundancy. Specifically, periphytic biofilms altered their composition with cyanobacteria, Sphingobacteriia and Spirochaetes being the newly dominant taxa, and changed the carbon substrate utilization pattern to maintain high photosynthesis and metabolic rates. Moreover, extracellular polymeric substances (EPS) especially proteins were overproduced to bind the NPs and thereby reduce the nanotoxicity. The information obtained in this study may greatly help to understand the interactions between microbial community dynamics and function under NPs exposure conditions and functional redundancy is an important mechanism of periphytic biofilms to maintain sustainable functions. [ABSTRACT FROM AUTHOR]

Nonpoint source (NPS) pollution produced by human activities in rural areas has induced excessive nutrient input into surface waters and the decline of water quality. The essence of NPS pollution is the transport of nutrients between soil and water. Traditional NPS pollution control strategies, however, are mainly based on the solid and liquid phases, with little focus on the bio-phase between water and soil. The pollutants produced from NPS can be regarded as a resource if recycled or reused in an appropriate way in the agricultural ecosystem. This mini review proposes novel strategies for NPS pollution control based on three phases (liquid, solid and bio-phase) and highlights the regulating services of an agricultural ecosystem by optimizing land use/cover types. [ABSTRACT FROM AUTHOR]

Innovative and cost-effective technologies for advanced nutrient removal from surface water are urgently needed for improving water quality. Conventional biotechnologies, such as ecological floating beds, or constructed wetlands, are not effective in removing nutrients present at low-concentration. However, microalgae-bacteria consortium is promising for advanced nutrient removal from wastewater. Suspended algal-bacterial systems can easily wash out unless the hydraulic retention time is long, attached microalgae-bacteria consortium is more realistic. This critical review summarizes the fundamentals and status of attached microalgae-bacteria consortium for advanced nutrient removal from surface water. Key advantages are the various nutrient removal pathways, reduction of nutrients to very low concentration, and diversified photobioreactor configurations. Challenges include poor identification of functional species, poor control of the community composition, and long start-up times. Future research should focus on the selection and engineering of robust microbial species, mathematical modelling of the composition and functionality of the consortium, and novel photobioreactor configurations. [ABSTRACT FROM AUTHOR]

Periphyton is widely distributed in paddy fields and its interactions with paddy soil and rice growth have been reported rarely. In this study, model paddy ecosystems with different additional soil substrates were simulated under controlled conditions to investigate the effects of periphyton on rice seed germination and seedling growth. Results show that the selected soil substrates had significant effects on the metabolic activities and growth of periphyton in paddy fields. The addition of straw to soil enhances but the addition of biochar leads to attenuation of periphyton growth. The presence of periphyton in the paddy system, especially with straw in soil greatly increased the germination index of rice seed (by maximally 21%). However, the biochar treatment in the presence of periphyton was detrimental for the seed vitality with a decrease of 30%. As a result, the periphyton cover on paddy soil surface significantly inhibited the growth of rice seedling, including rice height, leaf width and biomass. To summarize, this study indicates that the presence of periphyton during seed germination period was detrimental for rice growth, but could be used to control the weed growth. Thus, this study provided insight into understanding the periphyton-plant relationships with different soil-substrates and also new approaches to controlling weeds in paddy fields by regulating the growth of periphyton. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the bioremediation of agricultural solid waste leachates with high-concentrations of Cu (II) and Cd (II) after washing the wastes with water and Na 2 EDTA solution (0.2 M). Results indicate that Cu (II) and Cd (II) are mainly comprised of Cu 2 (OH) 2 2+ , Cu 3 (OH) 4 2+ , CuOH + , Cu(H 2 O) 4 (OH) 2 , Cd 2+ and CdOH + in the water-washed leachates and Cu(EDTA) 2− , Cu(HEDTA) − , Cd(EDTA) 2− and Cd(HEDTA) − in the Na 2 EDTA-washed leachates. Cu (II) removal efficiency by selected native periphyton from the water- and Na 2 EDTA-washed leachates were 80.5% and 68.4% respectively, and for Cd (II) it was 57.1% and 64.6%, because the periphyton was able to maintain a stable pH of the leachates and regulate its microbial composition and carbon metabolic capability to acclimate the chemical conditions of the leachates. This study provides a new biomeasure to treat leachates with high-concentration Cu 2+ and Cd 2+ , and contribute valuable insights into the relationships between periphyton characteristics and heavy metals. [ABSTRACT FROM AUTHOR]

Planted floating treatment bed (FTB) is an innovative technique of removing nutrients from polluted water but limited in deep water and cold seasons. Periphyton was integrated into FTB for a hybrid floating treatment bed (HFTB) to improve its nutrient removal capacity. To assess its potential for treating nutrient-polluted rivers, HFTB was up-scaled from 5 L laboratory tanks to 350 L outdoor tanks and then to a commercial-scale 900 m section of polluted river. Plants and periphyton interacted in HFTB with periphyton limiting plant root growth and plants having shading effects on periphyton. Non-overlapping distribution of plants and periphyton can minimize the negative interactions in HFTB. HFTB successfully kept TN and TP of the river at less than 2.0 and 0.02 mg L −1 , respectively. This study indicates that HFTB can be easily up-scaled for nutrients removal from polluted rivers in different seasons providing a long-term, environmentally-friendly method to remediate polluted ecosystems. [ABSTRACT FROM AUTHOR]

Benthic filamentous algae have evident advantages in wastewater treatment over unicellular microalgae, including the ease in harvesting and resistance to predation. To assess the potentials of benthic filamentous algae in treating horticultural wastewater under natural conditions in Belgium, three strains and their mixture with naturally wastewater-borne microalgae were cultivated in 250 ml Erlenmeyer flasks in laboratory as well as in 1 m 2 scale outdoor Algal Turf Scrubber (ATS) with different flow rates. Stigeoclonium competed well with the natural wastewater-borne microalgae and contributed to most of the biomass production both in Erlenmeyer flasks and outdoor ATS at flow rates of 2–6 L min −1 (water velocity 3–9 cm s −1 ), while Klebsormidium was not suitable for growing in horticultural wastewater under the tested conditions. Flow rate had great effects on biomass production and nitrogen removal, while phosphorus removal was less influenced by flow rate due to other mechanisms than assimilation by algae. [ABSTRACT FROM AUTHOR]

Bioremediation techniques based on microorganisms have been widely applied to treat polluted surface water, but the efficiencies have been limited, especially in deep and static waters. Microbial aggregates, known as periphyton, were introduced into a tank bioreactor to improve pollutants removal and a periphyton bioreactor with an 84 cm column was built to investigate microbe–wastewater interactions. Periphyton greatly improved water quality and produced a distinct stratification in the water column into five redox zones with slight overlaps. From top to bottom these were: oxygen reduction, nitrate reduction, iron reduction, sulfate reduction and methanogenic zone. Periphyton communities had high species diversities (767–947 OTUs) with the facultative zone (middle layer) having higher species richness and functional diversity than the aerobic (top layer) and anaerobic zones (bottom layer). A good knowledge of interactions between periphyton and water column stratification could benefit from integration of periphyton to improve bioremediation of deep and static water. [ABSTRACT FROM AUTHOR]

Although benthic filamentous algae are interesting targets for wastewater treatment and biotechnology, relatively little is known about their biochemical composition and variation in response to growth conditions. Fatty acid composition of four benthic filamentous green algae was determined in different culture conditions. Although the response was partly species-dependent, increasing culture age, nitrogen deprivation and dark exposure of stationary phase greatly increased both total fatty acid content (TFA) from 12–35 to 40–173 mg g −1 dry weight (DW) and the relative proportion of polyunsaturated fatty acids (PUFAs) from 21–58% to 55–87% of TFA, with dark exposure having the greatest effect. However, the main variation in fatty acid composition was between species, with Uronema being rich in C16:0 (2.3% of DW), Klebsormidium in C18:2ω6 (5.4% of DW) and Stigeoclonium in C18:3ω3 (11.1% of DW). This indicates the potential of the latter two species as potential sources of these PUFAs. [ABSTRACT FROM AUTHOR]

Periphyton-based bioreactors are widely accepted for removing various pollutants from wastewater; however, the slow start-up and low efficiency in widely fluctuating temperatures limit its application. A spiral periphyton bioreactor (SPR) was developed and its COD removal capability and the associated microbial communities were investigated. This SPR can be easily backwashed to stimulate periphyton growth and efficiently remove COD at temperatures ranging from 4 to 30 °C. The species richness and evenness of the periphyton community increased during domestication, while its functional diversity and organic carbon metabolic vitality were higher after 30 days domestication. Cyanobacteria were the main components of the SPR and produced an aerobic environment, while Alphaproteobacteria , Betaproteobacteria , Gammaproteobacteria and Sphingobacteria were the microorganisms responsible for COD removal. This study provides valuable insights into changes in pivotal microorganisms of the periphyton community during domestication, and indicates that SPR is simple to operate and efficient in COD removal. [ABSTRACT FROM AUTHOR]

The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5–15, 7–10 and 7–20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio. [ABSTRACT FROM AUTHOR]

It remains unclear whether periphytic biofilms are beneficial to N cycling in paddy fields. Here, based on a national‐scale field investigation covering 220 rice fields in China, the N accumulation potential of periphytic biofilms was found to decrease from 8.8 ± 2.4 to 4.5 ± 0.7 g/kg and 3.1 ± 0.6 g/kg with increasing habitat latitude and longitude, respectively. The difference in abundant and rare subcommunities likely accounts for their geo‐difference in N accumulation potential. The N cycling pathways involved in periphytic biofilms inferred that soil N and N2 were two potential sources for N accumulation in periphytic biofilms. Meanwhile, some of the accumulated N may be lost via N2, N2O, NO, or NH3 outputs. Superficially, periphytic biofilms are double‐edged swords to N cycling by increasing soil N through biological N fixation but accelerating greenhouse gas emissions. Essentially, augmented periphytic biofilms increased change of TN (ΔTN) content in paddy soil from −231.9 to 31.9 mg/kg, indicating that periphytic biofilms overall benefit N content enhancement in paddy fields. This study highlights the contribution of periphytic biofilms to N cycling in rice fields, thus, drawing attention to their effect on rice production and environmental security. [ABSTRACT FROM AUTHOR]

• Ag+ released from AgNPs has heavier impact on photosynthesis than intact AgNPs. • Ag+ blocks electron transport and damages phycobilisome of algae in periphyton. • Energy absorption is increased to maintain electron transfer in photosynthesis. • PSII and PSI work in complement to cope with stress by intact AgNPs and Ag+. Silver nanoparticles (AgNPs) including a mix of intact nanoparticle-Ag and 'free' Ag+ pose high risks to benthic photoautotrophs, but the photosynthetic responses of benthic microbial aggregates to AgNPs still remain largely unknown. Here, periphyton and Nostoc were used to elucidate the photosynthetic responses of benthic algae community to intact nanoparticle-Ag and Ag+. During exposure, both intact nanoparticle-Ag and Ag+ imposed negative effects on photosynthesis of benthic algae, but via different pathways. Specifically, Ag+ had stronger effects on damaging the oxygen-evolving complex (OEC) and thylakoid membrane than intact nanoparticle-Ag. Ag+ also suppressed electron transfer from Q A to Q B , and impaired phycobilisome. Intact nanoparticle-Ag inhibited the expression of PsbD and PsbL in PSII, but prompted the ROS scavenging capacity. In response to the stress of AgNPs, the benthic algae increased light energy absorption to maintain the electron transport efficiency, and up-regulated PSI reaction center protein (PsaA) to compensate the degraded PSII. These results reveal how intact nanoparticle-Ag and Ag+ influence electron transport, energy conversion and protein expression in the photosynthesis of periphyton, and provide deep insights into the responses of benthic photoautotrophs to different components of AgNPs. [ABSTRACT FROM AUTHOR]

Phototrophic biofilms are distributed widely at the sediment/soil-water interfaces (SWI) in paddy fields, where they immobilize phosphorus, thereby reducing its runoff loss. However, how soil carbon, nutrient availability and nutrient ratios drive the phototrophic biofilm community and its contribution to phosphorus cycling is largely unknown. A large scale field investigation in Chinese paddy fields reported here shows that soil organic carbon (SOC) and soil total nitrogen (STN) contents rather than soil total phosphorus (STP) triggered phosphorus immobilization of paddy biofilms, as they changed algal diversity and EPS production. High C: P and N: P ratios favored phosphorus immobilization in biofilm biomass via increasing the abundance of green algae. The C: N ratio on the other hand had only a weak effect on phosphorus immobilization, being counteracted by SOC or STN. Results from this study reveal how the in-situ interception of phosphorus in paddy fields is driven by soil carbon, nutrient availability and nutrient ratios and provide practical information on how to reduce runoff losses of phosphorus by regulating SOC and STN contents. Image 1 • Soil organic carbon, nitrogen, C/P and N/P are central in driving P immobilization. • Soil organic carbon and nitrogen counteract the effect of C/N on P immobilization. • Green algae and extracellular polymeric substances are vital in P immobilization. [ABSTRACT FROM AUTHOR]

With the continuous development of human life and society, the medical field is constantly improving. However, modern medicine still faces many limitations, including challenging and previously unsolvable problems. In these cases, artificial intelligence (AI) can provide solutions. The research and application of generative adversarial networks (GAN) are a clear example. While most researchers focus on image augmentation, there are few one-dimensional data augmentation examples. The radiomics feature extracted from RT and CT images is one-dimensional data. As far as we know, we are the first to apply the WGAN-GP algorithm to generate radiomics data in the medical field. In this paper, we input a portion of the original real data samples into the model. The model learns the distribution of the input data samples and generates synthetic data samples with similar distribution to the original real data, which can solve the problem of obtaining annotated medical data samples. We have conducted experiments on the public dataset Heart Disease Cleveland and the private dataset. Compared with the traditional method of Synthetic Minority Oversampling Technique (SMOTE) and common GAN for data augmentation, our method has significantly improved the AUC and SEN values under different data proportions. At the same time, our method has also shown varying levels of improvement in ACC and SPE values. This demonstrates that our method is effective and feasible. [ABSTRACT FROM AUTHOR]

Allelopathy among aquatic organisms, especially microorganisms, has received growing attention in recent years for its role in shaping interactions with bloom-forming algae. Many studies have shown that allelopathy occurs and increases under nutrient limiting conditions. However, to date there is no reported direct evidence to indicate that allelopathy occurs under the condition of constant high nutrient supply. Here we report the allelopathic action of periphytic biofilm on bloom-forming cyanobacteria (Microcystis aeruginosa), which was triggered by the stress of high nutrient conditions, and continues while nutrients are maintained at high levels (trophic state index at 159 and 171). The experimental evidence indicates that the electron transport from photosystem II (PS II) to photosystem I (PS I) in M. aeruginosa is interrupted by the identified allelochemicals, (9Z)-Octadec-9-enoic acid and (9Z)-Hexadec-9-enoic acid, leading to the failure of photosynthesis and the subsequent death of M. aeruginosa. Our findings indicate that the nutrient stress of constant high nutrient supply may be a newly recognized trigger causing allelopathy between microbial competitors, and therefore opening a new direction for the better management of ecological processes in cyanobacteria-dominated and hyper-eutrophic waters. [ABSTRACT FROM AUTHOR]

Objective. To evaluate the effect of hemp cotton sanitary pads on the vaginal microecology. Methods. A randomized controlled field trial was used to recruit 1002 community-based women of childbearing age. The women were randomly divided into experimental and control groups. The experimental group used hemp cotton sanitary pads, while the control group used two types of cotton sanitary randomly chosen from the top five sanitary pads in terms of market share in China. The vaginal microecology was compared between the two groups after three months. Results. According to the vaginal microecologic examination results at baseline, 1002 women were included in 3 groups: normal vaginal microecologic, vaginal microecological disorders, and suspected vaginal infections. The number of patients in three groups were 39 (3.9%), 652 (65.1%), and 311 (31%), respectively. Three months later, the vaginal microecologic status and vaginal pH value of the suspected vaginal infection group were not significantly different between the experimental group and control group. The experimental group outperformed the control group with respect to vaginal cleanliness and vaginal microecology status in the women without a vaginal infection (normal vaginal microecology or microecological disorders group). The rate of abnormal cleanliness in the experimental group was lower than the control group (31.95% [108/338] vs. 43.62% [154/353]). The incidence of suspected vaginitis in the experimental group was lower than the control group (15.29% [51/338] vs. 23.51% [83/353]). Conclusion. For women without vaginal inflammation, the use of hemp cotton sanitary pads during menstruation can help maintain the balance of the vaginal microecology to prevent reproductive tract infections. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • UCPs were first used to stimulate nitrogen removal of periphytic biofilms. • UCPs optimized the microbial community structure of periphytic biofilms. • Periphytic biofilms simulated by UCPs could adapt to nitrogen fluctuation. Abstract The application of periphytic biofilm in removing nitrogen from water is limited by the fluctuating nitrogen concentration. Here, we delineate a novel approach to enhance periphytic biofilm performance in nitrogen removal via upconversion luminescence of upconversion phosphors (UCPs). Nitrogen removal rates (14 d) in high nitrogen wastewater (26 mg/L) were significantly improved to 58.6% and 61.4% by UCPs doped with Pr3+ and Li+ and UCPs doped with Pr3+, respectively, and to 95.1% and 95.9% in low nitrogen surface water (2 mg/L), respectively. The stimulation of UCPs optimized the microbial community structure in the periphytic biofilms, and also resulted in good acclimation to use different carbon sources. The enhanced synergic action of cyanobacterial biomass, ratio of Gram +ve to Gram −ve bacteria and carbon source metabolic capacity contributed to the improved nitrogen removal. This novel approach is promising in nitrogen removal from wastewater and surface water with fluctuating initial nitrogen concentration. [ABSTRACT FROM AUTHOR]

The toxic effects of nanoparticles on individual organisms have been widely investigated, while few studies have investigated the effects of nanoparticles on ubiquitous multicommunity microbial aggregates. Here, periphyton as a model of microbial aggregates, was employed to investigate the responses of microbial aggregates exposed continuously to Fe2O3 nanoparticles (5.0 mg L-1) for 30 days. The exposure to Fe2O3 nanoparticles results in the chlorophyll (a, b, and c) contents of periphyton increasing and the total antioxidant capacity decreasing. The composition of the periphyton markedly changes in the presence of Fe2O3 nanoparticles and the species diversity significantly increases. The changes in the periphyton composition and diversity were due to allelochemicals, such as 3-methylpentane, released by members of the periphyton which inhibit their competitors. The functions of the periphyton represented by metabolic capability and contaminant (organic matter, nitrogen, phosphorus and copper) removal were able to acclimate to the Fe2O3 nanoparticles exposure via self-regulation of morphology, species composition and diversity. These findings highlight the importance of both physiological and ecological factors in evaluating the long-term responses of microbial aggregates exposed to nanoparticles. [ABSTRACT FROM AUTHOR]

The insufficient supply of electron donor in surface water contaminated with nitrate leads to its incomplete reduction in natural or constructed wetlands. Although the addition of organic matter (represented as chemical oxygen demand, COD) can stimulate N removal by denitrification, direct supplementation of COD creates unacceptable risks to effluent quality. An alternative for stimulating denitrification is supplying hydrogen gas (H 2 ) as an inorganic electron donor. We evaluate an innovative means to do H 2 -based denitrification of surface waters in a wetland setting: the in-situ membrane biofilm reactor (isMBfR), in which H 2 is delivered to a biofilm of denitrifying bacteria on demand based on the presence of nitrate. We carried out a proof-of-concept study in which an upper “photo zone” and a lower “MBfR root zone” were combined to remove nitrate and COD from simulated surface water. Employing mass-balances for H 2 , COD, nitrate, and oxygen, we documented nearly complete removals of nitrate and COD, except when the H 2 supply was intentionally shut off. All nitrate removal was accomplished in the “MBfR root zone,” where H 2 delivery supplemented the COD supply (as needed) and provided the large majority of electron equivalents to reduce nitrate to N 2 . [ABSTRACT FROM AUTHOR]

Interactions among microbes determine the prevalence of harmful algal blooms that threaten water quality. These interactions can be indirectly mediated by shared resources or consumers, or through interference by the production of allelochemicals. Allelopathic interactions and resource competition have been shown to occur among algae and associated microbes. However, little work has considered seasonal influences on ecosystem structure and function. Here, we report results of our investigations on seasonal changes in the interactions between benthic microbial assemblies and the bloom forming cyanobacterium Microcystis aeruginosa. We show that phosphorus (P) competition and allelopathy by the microbial assembly vary seasonally and inhibit growth of M. aeruginosa. The interactions per unit biomass of the microbial assembly are stronger under winter than summer conditions and inhibit the recruitment of the cyanobacteria, thereby preventing the reoccurrence of cyanobacterial blooms in the following summer. The seasonality of these interactions correlates with changes in composition, metabolic activity and functional diversity of the microbial assembly. Our findings highlight the importance of competitive and allelopathic interactions in regulating the occurrence of harmful algal blooms. Our results also imply that seasonal variation of competition and allelopathy of the microbial assembly might be beneficial to adjust aquatic ecosystem structure and function. [ABSTRACT FROM AUTHOR]

Production of sulfide and methane due to anaerobic biological transformations in sewer pipes causes serious problems to sewer maintenance. For gravity sewers, enhancing ventilation is a practical method that reduces the production of both sulfide and methane. This study aimed to determine the effectiveness of a new method, Upstream Natural Pulsed Ventilation (UNPV), to control sulfide and methane production in gravity sewers. Two lab-scale reactors simulating the gravity sewer pipe with and without ventilation were set up to assess the effectiveness. The results show that compared with the gravity sewer pipe without ventilation, under the UNPV condition, the total sulfide concentration reduced by 39.08% and 58.74%, and the methane concentration reduced by 42.29% and 35.70% in the upstream and downstream sewer pipe, respectively. High-throughput sequencing analysis showed that the UNPV method could inhibit the proliferation of sulfate-reducing bacteria and stimulate the proliferation of sulfur-oxidizing bacteria within the whole sewer pipe. The composition of methanogenic archaea that are responsible for methane production was changed by ventilation. The increased oxidation-reduction potential and organic carbon transportation in wastewater under ventilation may be responsible for the microbial community changes. The findings of this study may provide new insight to reduce sulfide and methane production in gravity sewers. Unlabelled Image • A simple method to control harmful gas in sewer by ventilation was proposed. • Sulfide emissions were reduced by ≈60% during upstream ventilation. • Methane emissions were reduced by ≈40% during upstream ventilation. • The biofilm community under ventilation was elucidated. [ABSTRACT FROM AUTHOR]

• IAA less than 10 mg/L inhibits the growth of periphytic biofilm. • IAA more than 50 mg/L stimulates growth of periphytic biofilm. • The removal rate of IAA by periphytic biofilm is 95%–100%. • IAA more than 50 mg/L stimulates the capacity of periphytic biofilm to remove IAA. Due to its extensive application in agriculture as a germinating agent and growth promoter, indole acetic acid (IAA) is present in a variety of aquatic ecosystems. To explore the response of microbial aggregates to exogenous IAA in aquatic ecosystems, periphytic biofilm, a typical microbial aggregate, was exposed to IAA at different concentrations. Results reveal an unexpected concentration-dependent effect of IAA on periphytic biofilm. Concentrations of IAA less than 10 mg/L inhibit periphytic growth, but stimulate growth when the IAA concentration exceeds 50 mg/L. Periphytic biofilm adapts to different IAA concentrations by antioxidant enzyme activation, community structure optimization and carbon-metabolism pattern change, and promotes bioremediation of IAA contaminated water in the process. The removal rates of IAA reached up to 95%–100%. This study reveals the capacity of periphytic biofilm for IAA removal in practice. [ABSTRACT FROM AUTHOR]