Hotspots Of Activity Research Articles

Io’s polar volcanic thermal emission indicative of magma ocean and shallow tidal heating models

The distribution of Io’s volcanic activity probably reflects the position and magnitude of internal tidal heating, but full mapping of the moon has not been possible due to a lack of polar coverage. Here we use new observations of Io’s polar regions by the Juno spacecraft Jovian Infrared Auroral Mapper to complete near-infrared coverage, revealing the global distribution and magnitude of thermal emission from Io’s currently erupting volcanoes. We show that the distribution of volcanic heat flow from 266 active hot spots is consistent with the presence of a global magma ocean and/or shallow asthenospheric heating. We find that Io’s polar volcanoes are less energetic but approximately the same in number per unit area than those at lower latitudes. We also find that volcanic heat flow in the north polar cap is greater than that in the south. The low volcanic advection seen at Io’s poles is therefore at odds with measurements of background temperature, showing that Io’s poles are anomalously warm. We suggest that the differences in volcanic thermal emission from Io’s poles compared with those at lower latitudes are indicative of lithospheric dichotomies that inhibit volcanic advection towards Io’s poles, particularly in the south polar region.

Taxonomic distribution of metabolic functions in bacteria associated with Trichodesmium consortia.

Colonies of the cyanobacteria Trichodesmium act as a biological hotspot for the usage and recycling of key resources such as C, N, P, and Fe within an otherwise oligotrophic environment. While Trichodesmium colonies are known to interact and support a unique community of algae and particle-associated microbes, our understanding of the taxa that populate these colonies and the gene functions they encode is still limited. Characterizing the taxa and adaptive strategies that influence consortium physiology and its concomitant biogeochemistry is critical in a future ocean predicted to have increasingly resource-depleted regions.

Recent seismicity on the Kerguelen islands

The Kerguelen archipelago, one of the largest oceanic archipelagos in the world, was built by an active hotspot interacting with a ridge between 110 and 40 million years ago; since then, the ridge has migrated over 1000~km away and the archipelago's volcanic activity has been steadily decreasing. Despite the lack of recent active tectonics and the quiescent volcanism of the Kerguelen archipelago, there have been several observations of seismic events of unknown origin in its vicinity. The only seismic instrument within 1000~km of the archipelago was installed on Kerguelen's main island in the 1980's. In this study we apply modern earthquake detection techniques to the continuous waveforms recorded by this seismometer over the past 20 years. We reveal that the Kerguelen archipelago islands hosts an abundant seismicity. This seismicity exhibits swarm-like characteristics in several clusters while at other locations the earthquakes appear more steady over time. We locate most events near the largest icecap of the main island. We speculate that the origin of the earthquakes can be linked to residual volcanic, magmatic, or hydrothermal activity at depth, all of which can be favored by flexural stress caused by the documented fast retreat of icecap. This seismicity may also indicate that the Kerguelen hotspot shows signs of unrest.

An algorithm for extracting similar segments of moving target trajectories based on shape matching

Trajectory similarity analysis of moving target is the foundation for mining high-value and regular behavioral information such as motion preferences, activity hotspots and frequent paths. Unlike most trajectory similarity analysis methods aimed at discovering correlations of target activities in time, space or spatio-temporal domains, this paper focuses on the shape matching of target trajectories. If some specific shapes frequently appear in historical trajectories, extracting these local shapes would be beneficial for analyzing the target motion templates and behavior modes. Trajectory segments with similar shapes may not have spatio-temporal correlation, and the shapes also have geometric transformation characteristics such as rotation, scaling and translation. Since the existing trajectory similarity analysis methods cannot be directly applied, an algorithm for extracting similar segments based on shape matching is proposed. First, a new shape descriptor based on signed barycenter distance (SBD) is established. It describes a trajectory as a one-dimensional shape feature sequence, which has the advantage of low computational complexity. Then, the distributed nearest neighbor search strategy is used in the particle swarm optimization (PSO) method, which aims to accelerate the retrieval of trajectory segments with similar shapes and improve the matching accuracy. Experiments on MPEG-7, handwritten character and maneuvering target simulation trajectory data sets show that compared with the existing typical shape descriptors, SBD shape descriptor has advantages in accuracy and noise insensitivity, and the improved PSO method can efficiently and accurately obtain the local shape matching results.

Radiation impacts gene redundancy and biofilm regulation of cryoconite microbiomes in Northern Hemisphere glaciers

BackgroundGlaciers harbor diverse microorganisms adapted to extreme conditions with high radiation, fluctuating temperature, and low nutrient availability. In glacial ecosystems, cryoconite granules are hotspots of microbial metabolic activity and could influences the biogeochemical cycle on glacier surface. Climate change could influence glacier dynamics by changing regional meteorological factors (e.g., radiation, precipitation, temperature, wind, and evaporation). Moreover, meteorological factors not only influence glacier dynamics but also directly or indirectly influence cryoconite microbiomes. However, the relationship of the meteorological factors and cryoconite microbiome are poorly understood.ResultsHere, we collected 88 metagenomes from 26 glaciers distributed in the Northern Hemisphere with corresponding public meteorological data to reveal the relationship between meteorological factors and variation of cryoconite microbiome. Our results showed significant differences in taxonomic and genomic characteristics between cryoconite generalists and specialists. Additionally, we found that the biogeography of both generalists and specialists was influenced by solar radiation. Specialists with smaller genome size and lower gene redundancy were more abundant under high radiation stress, implying that streamlined genomes are more adapted to high radiation conditions. Network analysis revealed that biofilm regulation is a ubiquitous function in response to radiation stress, and hub genes were associated with the formation and dispersion of biofilms.ConclusionThese findings enhance our understanding of glacier cryoconite microbiome variation on a hemispheric scale and indicate the response mechanisms to radiation stress, which will support forecasts of the ecological consequences of future climate change.3hvtG_8RFcL8puNgr6T9zaVideo

The Occurrence, Variability, and Potential Drivers of Submesoscale Eddies in the Southern California Bight Based on a Decade of High‐Frequency Radar Observations

AbstractSubmesoscale eddies form an important component of the circulation of the Southern California Bight (SCB). Despite their acknowledged significance in influencing ocean physics, biology, and ecological processes, submesoscale eddies have been exceptionally hard to study and observe because of the technical challenges posed by both field and remote platforms. Here, using a decade of high‐frequency radar surface current observations, we describe submesoscale eddies in the SCB. Between 2012 and 2021, a total of ∼235,000 eddies were detected, averaging 452 ± 116 eddies per week. Recurring eddies in certain locations over time, formed hotspots of eddy activity, largely in association with topographical features. On seasonal scales, eddies were more numerous in the summer and early fall. At inter‐annual scales, eddy counts increased by 40% in association with the 2014–2015 marine heatwave and the 2015–2016 El Niño. A domain‐wide diurnal cycle was observed in the formation of eddies and the normalized vorticity. To determine the relative contributions of tides and diurnal winds, an analysis of spectral components and their spatial distribution along the SCB was conducted. The results revealed that while diurnal tides may exert some influence on the diurnal variations, their effect is comparatively minor when compared to diurnal winds. This conclusion was reached by considering the prevalence of the S1 frequency, which is a meteorological tide known to be associated with motions induced by sea‐land breeze. Overall, diurnal variability was more prominent in the southern SCB and less significant toward the north.

Global research trends of immunosenescence: A bibliometric study

BackgroundImmunosenescence, an age-related deficit in immunity, associated with multiple disorders and making the successful aging a challenge. Although nearly 4000 articles have been published, only few review articles have summarized the research status. In order to better understand the most recent advances, hotspots and development trends in immunosenescence, it is very necessary to conduct a comprehensive bibliometric analysis. Hence, commonly used bibliometric analysis software CiteSpace and VOSviewer were employed to conduct a quantitative analysis and critical evaluation of publications in this study. MethodsImmunosenescence publications were screened from the Web of Science Core Collection (WoSCC). Microsoft Excel 2021, CiteSpace 5.8.R3, and VOSviewer 1.6.17 were used for bibliometric study. ResultsA total of 3875 publications were retrieved from WoSCC. After screening by document type (article or review) (352 publications were excluded) and language of English (85 were excluded), 3438 studies were finally used for bibliometric analysis. The literature on immunosenescence had been continuously growing since 1991, and by 2020 it has skyrocketed 312 publications from 240 in 2019. USA (1111 publications, 35.01%) was the leading country of publications, followed by ITALY (379, 11.94%) and ENGLAND (366, 11.53%). Of the authors, Pawelec G from the Tubingen University of GERMANY contributed the greatest articles (93 publications). All the keywords could be divided into five clusters, and additional potent visualization bursts revealed that “gut microbiota,” “health,” “dysfunction,” and “nivolumab” were the active hotspots presently. ConclusionBased on the current data, we firstly concluded that there will be a dramatically rising publications on immunosenescence, and research teams from USA or GERMANY might be the best chooses for collaboration. Moreover, We particularly emphasized the development potential of mechanism and intervening strateges like “gut microbiota” and “nivolumab” in immunosenescence. We hope to provide new ideas for promoting the basic research and clinical application of immunosenescence.

Restoring the mind: A neuropsychological investigation of university campus built environment aspects for student well-being

This study explored the role of the built environment of an academic campus in influencing students' perception of mental restoration and well-being, who are constantly at risk of stress and psychological distress. A survey of 429 college students was conducted to identify activity hotspots on campus, and a neuropsychological study involving mobile EEG and Perceived Restorativeness Scale (PRS) was conducted on 22 students at these hotspots to investigate the role of built environment aspects on restorative approach/neglect behavior and perception of built environment. The study relies on four prominent theoretical constructs in the area, namely Attention Restoration Theory (ART), Stress Reduction Theory (SRT), Arousal Theory, and Prospect & Refuge Theory, to develop combinatory mechanism-based hypotheses for identifying aspects of a mentally resilient campus built-environment. The study's statistical analyses reveal that certain environmental aspects, such as vegetation, novelty/uncertainty, acoustic ambience, and expansive vistas, are positively associated with favourable approach behaviours and normalized average alpha brain waves, while other elements, such as presence of high density of buildings may be related to avoidance behaviours. Greenery and Sky had the most positive relationship with the Normalized Alpha (β = 0.487 and β = 0.352, respectively) while the presence of buildings revealed a negative relationship (β = −0.291), indicating that a stronger building density was linked to a weaker level of normalized alpha waves. The study also shows that natural components such as grass, sky, and filtered and diffused light boost people's perceptions of an environment's restorative characteristics. The findings of the study have the potential to impact campus design and planning strategies that prioritize student well-being and create more hospitable environments for students to thrive, resulting in improved mental health and academic accomplishment.

Campus node-based wastewater surveillance enables COVID-19 case localization and confirms lower SARS-CoV-2 burden relative to the surrounding community

Wastewater-based surveillance (WBS) has been established as a powerful tool that can guide health policy at multiple levels of government. However, this approach has not been well assessed at more granular scales, including large work sites such as University campuses. Between August 2021 and April 2022, we explored the occurrence of SARS-CoV-2 RNA in wastewater using qPCR assays from multiple complimentary sewer catchments and residential buildings spanning the University of Calgary's campus and how this compared to levels from the municipal wastewater treatment plant servicing the campus. Real-time contact tracing data was used to evaluate an association between wastewater SARS-CoV-2 burden and clinically confirmed cases and to assess the potential of WBS as a tool for disease monitoring across worksites. Concentrations of wastewater SARS-CoV-2 N1 and N2 RNA varied significantly across six sampling sites – regardless of several normalization strategies – with certain catchments consistently demonstrating values 1–2 orders higher than the others. Relative to clinical cases identified in specific sewersheds, WBS provided one-week leading indicator. Additionally, our comprehensive monitoring strategy enabled an estimation of the total burden of SARS-CoV-2 for the campus per capita, which was significantly lower than the surrounding community (p≤0.001). Allele-specific qPCR assays confirmed that variants across campus were representative of the community at large, and at no time did emerging variants first debut on campus. This study demonstrates how WBS can be efficiently applied to locate hotspots of disease activity at a very granular scale, and predict disease burden across large, complex worksites.

Scientific Knowledge Graph of Dysmenorrhea: A Bibliometric Analysis from 2001 to 2021.

This study aims to help researchers master the most active hotspots and trends quickly through bibliometric analysis in the field of dysmenorrhea. We retrieved literature on Web of Science from 2001 to 2021, and bibliometric analysis software CiteSpace was used in combination with VOSviewer. We finally acquired 944 papers and an upward trend in articles continued in this field overall. Through the map, China contributed the most, followed by the USA and Turkey. For institutions, Beijing University of Chinese Medicine in China contributed the most, followed by National Yang-Ming University in Taiwan, China. Hsieh JC and Hellman KM were both the most prolific authors with 14 articles. Five major research groups, respectively, with Hsieh JC, Hellman KM, Zhu J, Liang F and Dun W were the key group. Dawood MY was the most dominant author and most frequently cited author. The Cochrane Database of Systematic Reviews Journal was the most productive, and the Fertility and Sterility Journal was the most cited. Advances in pathogenesis and management for primary dysmenorrhea written by Dawood MY was most cited and influential. Pathophysiology, the potential central mechanism, syndrome, evaluation index, diagnosis of adenomyosis-associated dysmenorrhea, treatment, etc., were the main trends and hotspots. Dysmenorrhea research has received a lot of attention from scholars. Strengthening international cooperation may promote the development of this field. The pathophysiology of dysmenorrhea, its impact on public health and its treatment are current research hotspots and are likely to be the focus of future study.

Bio-converted organic wastes shape microbiota in maize rhizosphere: Localization and identification in enzyme hotspots

Organic fertilizers increase soil fertility, microbial diversity and heterogeneity of microbial activity hotspots. Black soldier fly (Hermetia illucens L.) frass (BSFF) derived from organic waste composts has been extensively marketed as organic fertilizer, but its effects on rhizosphere microbiota remain unknown. We compared the effects of BSFF from three organic wastes (straw, manure, and kitchen waste) on maize growth in acidic soils. Sufficient P, an optimal soil pH, and a satisfactory soil C/N ratio, as provided by the straw-derived frass, increased the maize growth more than the other frass types. Maize growth increased due to nutrient mobilization by active rhizosphere microbiota, which was localized using in situ soil zymography and identified through DNA amplicon sequencing and quantitative PCR. Specifically, the area of hotspots of acid phosphatase activity along the maize roots increased for 2.8 times after straw-derived frass application compared to unamended soils. Microbial diversity raised within these enzyme activity hotspots and was accompanied by the increased abundances of plant growth-promoting microbial taxa like Luteibacter, Chrysosporium, and Cladorrhinum. Microorganisms formed efficient and mutualistic networks within the rhizosphere hotspots induced by straw-derived frass to accelerate organic P mineralization, as inferred by random forest analysis and the quantitative of phoC and phoD genes. Concluding, the straw-derived frass benefits maize growth on acidic soils through abiotic (soil physico-chemical properties) and biotic (active rhizosphere microbiota) stimuli.

Is the Northern Goshawk an Efficient Bioindicator of Avian Abundance and Species Richness in Urban Environments?

Monitoring of biodiversity in expanding urban areas is an essential part of wildlife conservation. There is evidence that raptors, such as Northern Goshawks (Accipiter gentilis), are effective bioindicator species in urban areas, however, their relationship with other bird populations is not clearly established. We asked whether activity patterns of Goshawks are a reliable indicator of wintering bird abundance and diversity in urban ecosystems. We tracked the movement of eight GPS-tagged Goshawks in the city of Tartu (Estonia) and analysed the numbers and diversity of birds in the same area using direct mapping and occasional data obtained from birdwatchers. The direct mapping approach revealed that the number of birds and avian species richness were higher in Goshawk activity hotspots than at random sites in 2022, however, no such differences were detected in 2023. Analysis of occasional citizen-collected data showed no effect of avian abundance nor species richness on the distribution of Goshawk activity. These results suggested that the movements of Goshawks may indicate the abundance and diversity of its prey, however, this relationship depends on the detection methodology. Hence, raptors are a promising bioindicator in urban environments, but results should be interpreted with caution, particularly when using citizen-collected data.

Soil Enzyme Activity Response to Substrate and Nutrient Additions on Undisturbed Forest Subsoil Samples

Previous studies have found that C turnover is bound to hotspots of microbial activity. The objective of this study was to analyze the effects of pure energy substrate (glucose), nutrient (mineral N or P) and combined substrate and nutrient (glucose + N, glucose + P, sterile DOC, artificial root exudate extract) additions to enzyme activity inside and outside hotspots as a proxy for microbial C turnover in a subsoil. By means of different substrate and nutrient additions, we tested how the limitations of our site were distributed on a small scale and depth-dependently to contribute to an increase in knowledge of subsoil mechanistics. The study site is a sandy Dystric Cambisol under an over 100-year-old beech forest stand in Lower Saxony, Germany. Forty-eight undisturbed soil samples from two depth increments (15–27 cm and 80–92 cm) of three profiles were sprayed homogeneously with easily available C, N and P sources to investigate the impacts of substrates and nutrients on three enzyme activities (acid phosphatase, β-glucosidase and N-acetylglucosaminidase) by using the soil zymography approach. Comparisons of upper and lower subsoils showed significantly fewer and smaller hotspots in the lower subsoil but with a high degree of spatial variation in comparison to the upper subsoil. Different patterns of enzyme distribution between upper and lower subsoil suggest microbial communities with a lower diversity are found in deeper soil regions of the site. Both substrate and nutrient additions stimulated enzyme activities significantly more outside the initial hotspots than within. Because of this, we conclude that microorganisms in the initial hotspots are less limited than in the surrounding bulk soil. Changes in enzyme activities owing to both substrate and nutrient addition were stronger in the lower subsoil than in the upper subsoil, showing differences in limitations and possible changes in microbial community structure with increasing depth. The results of our study emphasize the need to consider spatial factors in microbial turnover processes, especially in lower subsoil regions where stronger substrate and nutrient limitations occur.

Efficient site-specific integration in CHO-K1 cells using CRISPR/Cas9-modified donors.

Conventional methods applied to develop recombinant CHO (rCHO) cell line as a predominant host for mammalian protein expression are limited to random integration approaches, which can prolong the process of getting the desired clones for months. CRISPR/Cas9 could be an alternative by mediating site-specific integration into transcriptionally active hotspots, promoting homogenous clones, and shortening the clonal selection process. However, applying this approach for the rCHO cell linedevelopment depends on an acceptable integration rate and robust sites for the sustained expression. In this study, we aimed at improving the rate of GFP reporter integration to the Chromosome 3 (Chr3) pseudo-attP site of the CHO-K1 genome via two strategies; these include the PCR-based donor linearization and increasing local concentration of donor in the vicinity of DSB site by applying the monomeric streptavidin (mSA)-biotin tethering approach. According to the results, compared to the conventional CRISPR-mediated targeting, donor linearization and tethering methods exhibited 1.6- and 2.4-fold improvement in knock-in efficiency; among on-target clones, 84% and 73% were determined to be single copy by the quantitative PCR, respectively. Finally, to evaluate the expression level of the targeted integration, the expression cassette of hrsACE2 as a secretory protein was targeted to the Chr3 pseudo-attP site by applying the established tethering method. The generated cell pool reached 2-fold productivity, as compared to the random integration cell line. Our study suggested reliable strategies for enhancing the CRISPR-mediated integration, introducing Chr3 pseudo-attP site as a potential candidate for the sustained transgene expression, which might be applied to promote the rCHO cell linedevelopment.

Estimating hidden fishing activity hotspots from vessel transmitted data

Monitoring fishery activity is essential for resource planning and guaranteeing fisheries sustainability. Large fishing vessels constantly and continuously communicate their positions via Automatic Identification System (AIS) or Vessel Monitoring Systems (VMSs). These systems can use radio or Global Positioning System (GPS) devices to transmit data. Processing and integrating these big data with other fisheries data allows for exploring the relations between socio-economic and ecosystem assets in marine areas, which is fundamental in fishery monitoring. In this context, estimating actual fishing activity from time series of AIS and VMS data would enhance the correct identification of fishing activity patterns and help assess regulations' effectiveness. However, these data might contain gaps because of technical issues such as limited coverage of the terrestrial receivers or saturated transmission bands. Other sources of data gaps are adverse meteorological conditions and voluntary switch-offs. Gaps may also include hidden (unreported) fishing activity whose quantification would improve actual fishing activity estimation. This paper presents a workflow for AIS/VMS big-data analysis that estimates potential unreported fishing activity hotspots in a marine area. The workflow uses a statistical spatial analysis over vessel speeds and coordinates and a multi-source data integration approach that can work on multiple areas and multiple analysis scales. Specifically, it (i) estimates fishing activity locations and rebuilds data gaps, (ii) estimates the potential unreported fishing hour distribution and the unreported-over-total ratio of fishing hours at a 0.01° spatial resolution, (iii) identifies potential unreported fishing activity hotspots, (iv) extracts the stocks involved in these hotspots (using global-scale repositories of stock and species observation data) and raises an alert about their possible endangered, threatened, and protected (ETP) status. The workflow is also a free-to-use Web Service running on an open science-compliant cloud computing platform with a Web Processing Service (WPS) standard interface, allowing efficient big data processing. As a study case, we focussed on the Adriatic Sea. We reconstructed the monthly reported and potential unreported trawling activity in 2019, using terrestrial AIS data with a 5-min sampling period, containing ~50 million records transmitted by ~1,600 vessels. The results highlight that the unreported fishing activity hotspots especially impacted Italian coasts and some forbidden and protected areas. The potential unreported activity involved 33 stocks, four of which were ETP species in the basin. The extracted information agreed with expert studies, and the estimated trawling patterns agreed with those produced by the Global Fishing Watch.

Long-term photometric behavior and orbital period variations in the supersoft X-ray source V617 Sgr

V617 Sgr is one of the Galactic counterparts of supersoft X-ray sources as a member of the V Sagittae class, where a massive white dwarf is accreting material from its stellar companion and forming an accretion disk. Since 2014, we have monitored it for about nine years with the 2.15m telescope at CASLEO. It is found that the light curve shows obviously fluctuations and flickering, which imply the presence of active hot-spots on the accretion disk. Meanwhile, the flat-bottomed depressions can be explained by the presence of circumbinary material. By collecting all available eclipse times from the literature together with 149 newly determined times of light minimum, we constructed the O-C diagram and analyzed the variations in the orbital period of the eclipsing binary V617 Sgr. It is confirmed that the orbital period is increasing continuously with a rate of Ṗ=+1.68(3)×10−7 d yr−1. A cyclic variation is detected to be superimposed on the period increase with an amplitude of 4.6 min and a period of 26yr. The continuous period increase is largely due to mass transfer from the donor secondary on its Kelvin–Helmholtz time-scale, while wind mass loss from the accretion disk surrounding the white dwarf may also contribute on the period change. In this case, the mass-transfer rate of V617 Sgr is estimated to be in the range of about 0.575×10−6 to 2.25×10−6M⊙ yr−1 and the mass-accretion rate is less than 1.59×10−6M⊙ yr−1. The cyclic change can be explained by the presence of a third body or magnetic activity cycles of the secondary.

The Study of The Economic Distribution Characteristics of Night Economic Distribution Based on Multi-source Data Fusion

The night economy is an important representation of urban economic development and consumption level. Based on the night lighting, the data of the POI data, the data of the spatial clustering algorithm of DBSCAN、K-means and other spatial clustering algorithms and the study of the profit and loss of supply and demand, the model of the area and the area domain analysis of the night activity hotspot area and night service facility are established. The fusion of multi-source data provides a new perspective for the night economy, which is more rapid, efficient and extensive than the traditional survey data, which is suitable for the large-scale study of the night economy.

Virtual Screening Strategy to Identify Retinoic Acid-Related Orphan Receptor γt Modulators.

Molecular docking is a key method used in virtual screening (VS) campaigns to identify small-molecule ligands for drug discovery targets. While docking provides a tangible way to understand and predict the protein-ligand complex formation, the docking algorithms are often unable to separate active ligands from inactive molecules in practical VS usage. Here, a novel docking and shape-focused pharmacophore VS protocol is demonstrated for facilitating effective hit discovery using retinoic acid receptor-related orphan receptor gamma t (RORγt) as a case study. RORγt is a prospective target for treating inflammatory diseases such as psoriasis and multiple sclerosis. First, a commercial molecular database was flexibly docked. Second, the alternative docking poses were rescored against the shape/electrostatic potential of negative image-based (NIB) models that mirror the target's binding cavity. The compositions of the NIB models were optimized via iterative trimming and benchmarking using a greedy search-driven algorithm or brute force NIB optimization. Third, a pharmacophore point-based filtering was performed to focus the hit identification on the known RORγt activity hotspots. Fourth, free energy binding affinity evaluation was performed on the remaining molecules. Finally, twenty-eight compounds were selected for in vitro testing and eight compounds were determined to be low μM range RORγt inhibitors, thereby showing that the introduced VS protocol generated an effective hit rate of ~29%.

Effect of polylactic acid microplastics on soil properties, soil microbials and plant growth

Biodegradable plastic is considered one of the most promising alternatives to agricultural mulch. However, the impact of biodegradable microplastics on agricultural ecosystems is still lacking. We conducted a controlled experiment with polylactic acid microplastics (PLA MPs) to examine the effects of biodegradable plastic on soil properties, corn growth, the microbial community and hotspots of enzyme activity. The results showed that PLA MPs in soil significantly reduced the soil pH value but increased the soil C:N ratio. High levels of PLA MPs significantly reduced the biomass of plant shoots and roots as well as chlorophyll, leaf C and N and root N contents. PLA MPs increased bacterial abundance but decreased the abundance of dominant fungal taxa. As the level of PLA MPs increased, the soil bacterial community structure became more complex, while the fungal community became more singular. The results of the in situ zymogram showed that low levels of PLA MPs increased the hotspots of enzyme activity. The effect of PLA MPs on enzyme activity hotspots was regulated by a combination of soil properties and microbial diversity. Generally, the addition of PLA MPs at high concentrations will have a negative impact on soil characteristics, soil microbials and plant growth in a short period of time. Therefore, we should be aware of the potential risks of biodegradable plastic to agricultural ecosystems.

Electrochemical Synthesis of a WO3/MoSx Heterostructured Bifunctional Catalyst for Efficient Overall Water Splitting

Photo-/electrochemical water splitting can be a suitable method to produce “green” hydrogen and oxygen by utilizing renewable energy or even direct sunlight. In order to carry out photoelectrochemical (PEC) water splitting, a photoanode based on transition metal oxides, which absorbs photons and produces photoexcited electron–hole pairs, is needed. The positively charged holes can then participate in the water oxidation reaction. Meanwhile, a cathodic hydrogen evolution reaction (HER) can occur more efficiently with electrocatalytic materials that enhance the adsorption of H+, such as MoS2. In this study, it was shown that WO3/MoSx heterostructured materials can be synthesized by an electrochemical method called plasma electrolytic oxidation (PEO). During this process, many micro-breakdowns of the oxide layer occur, causing ionization of the oxide and electrolyte. The ionized mixture then cools and solidifies, resulting in crystalline WO3 with incorporated MoSx. The surface and cross-sectional morphology were characterized by SEM-FIB, and the coatings could reach up to 3.48 μm thickness. Inclusion of MoSx was confirmed by EDX as well as XPS. Synthesis conditions were found to have an influence on the band gap, with the lowest value being 2.38 eV. Scanning electrochemical microscopy was used to map the local HER activity and correlate the activity hotspots to MoSx’s content and surface topography. The bifunctional catalyst based on a WO3/MoSx heterostructure was evaluated for PEC and HER water-splitting activities. As a photoanode, it could reach up to 6% photon conversion efficiency. For HER in acidic media, a Tafel slope of 42.6 mV·dec−1 can be reached.