Dispersive Filter Research Articles

Competitive exclusion drives termite community assembly process on islands

ContextAbiotic filtering, including environmental and dispersal filtering, is frequently observed resulting in reduced diversity and more similar species assemblages following habitat fragmentation. Nonetheless, the significance of competitive exclusion is often underestimated.ObjectivesWe investigated the dominant assembly process among termite communities on land-bridge islands, focusing on species known for their high territoriality. We hypothesized that competitively superior species tend to dominate more favorable habitats, such as larger and less isolated islands. Consequently, we anticipated lower diversity and greater similarity in species assemblages than would be expected.MethodsTermite communities were surveyed using standardized transects on 24 islands. We quantified the standardized effects of island area and isolation on taxonomic, phylogenetic and functional diversity by comparing observed patterns with randomly generated communities (i.e., stochastic process). A phylogenetic generalized linear mixed model (PGLMM) was conducted to examine species-specific responses to environmental factors and competition intensity (i.e., heterospecific abundance).ResultsWe found that taxonomic, phylogenetic and functional diversity were lower than expected on larger and less isolated islands, suggesting that competitive exclusion was the dominant mechanism shaping termite communities in TIL. PGLMM showed that two fungus-growing species with larger body sizes increased with competition intensity, while other species exhibited negative responses. Notably, the abundance of fungus-growing species showed sharper increase with island area and decrease with isolation compared to other feeding groups. These findings demonstrate that competitively superior species prefer high-quality habitats and are more sensitive to habitat fragmentation.ConclusionsOur study highlights the significance of competitive exclusion in shaping termite communities and emphasizes the need to consider both competitive and niche difference among species or functional groups when predict changes in community structure and biodiversity loss resulting from habitat fragmentation.

Molecularly imprinted resin modified with ionic liquid for dispersive filter extraction and determination of perfluoroalkyl acids in eggs

Perfluoroalkyl acids (PFAAs) are emerging pollutants that endangers food safety. Developing methods for the selective determination of trace PFAAs in complex samples remains challenging. Herein, an ionic liquid modified porous imprinted phenolic resin-dispersive filter extraction-liquid chromatography-tandem mass spectrometry (IL-PIPR−DFE−LC-MS/MS) method was developed for the determination of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in eggs. The new IL-PIPR adsorbent was prepared at room temperature, which avoids the disorder and instability of the template at high temperatures. The imprinting factor of IL-PIPR for PFOA and PFOS exceeded 7.3. DFE, combined with IL-PIPR (15 mg), was used to extract PFOA and PFOS from eggs within 15 min. The established method exhibits low limits of detection (0.01–0.02 ng/g) and high recoveries (84.7%–104.7%), which surpass those of previously reported methods. This work offers a new approach to explore advanced imprinted adsorbents for PFAAs, efficient sample pretreatment technique, and analytical method for pollutants in foods.

Rapid determination of polyhalogenated carbazoles in water chestnut based on vortex assisted solvent extraction coupled with dispersive filter extraction followed by gas chromatography-tandem mass spectrometry

Polyhalogenated carbazoles (PHCZs), originating from the production and use of halogenated indigo dyes, photoelectric materials, and p-chloraniline structure herbicides, pose a threat to water environments, aquatic products, and consequently human health. Therefore, establishing an accurate detection method for PHCZs in aquatic products is of paramount importance. In this study, trace PHCZs (36-CCZ, 36-BCZ, and 1368-BCZ) in water chestnut were detected for the first time using the prepared polyvinyl alcohol-functionalized graphene aerogel (PGA) as a novel adsorbent for dispersive filter extraction (DFE), coupled with vortex assisted solvent extraction (VASE), followed by gas chromatography-tandem mass spectrometry (GC–MS/MS). The extraction process (VASE-DFE) has the advantages of good purification effect, short extraction time (<15 min), and low adsorbent dosage (1.0 mg). This method demonstrated excellent linearity in the range of 0.10/0.50/1.00–200 ng/g for the three PHCZs (R2 ≥ 0.9995), and the recoveries at three spiked levels (2, 20, 100 ng/g) ranged from 82 % to 93 %, with relative standard deviations (RSDs) ≤ 7.4 %. Notably, the method outperforms previously reported adsorbents in terms of RSDs, adsorbent dosage, and extraction time. The VASE-DFE-GC–MS/MS method provides a new approach for the detection of trace pollutants in complex samples, introduces a novel technology for environmental and food safety monitoring, and contributes to enhancing food safety supervision.

A network of biological traits: Profiling consumer-resource interactions

Trophic interactions can be both ephemeral and difficult to document, rendering their sampling often incomplete and context-dependent, which makes construction, analysis, and comparison of food webs challenging. Biological traits are central in determining co-occurrence of species (through dispersal, environmental, and interaction filters), as well as the potential for species interactions (through trait matching). Thereby, supplementing empirical, taxonomy-based information on trophic links with trait-based inference may help us build more realistic and adaptable food webs. Here, we go beyond taxonomy to document (i) how traits (e.g., body size, metabolic category and feeding strategy) contribute to local food web structure, and (ii) how associations of consumer-resource traits are structured. We built a trophic-link based trait-interaction network—or trait web—by combining multivariate approaches and network analysis. We found that consumer-resource associations organize into trait profiles that reflect the general vertical structure of the food web, as well as identify groups of limited sets of highly interacting traits. Finally, we discuss the implications of the findings for generating comprehensive and adaptive food webs.

Equivalent roles of marine subsidies and island characteristics in shaping island bird communities

AbstractAimSpecies distributions across islands are shaped by dispersal limitations, environmental filters and biotic interactions but the relative influence of each of these processes has rarely been assessed. Here, we examine the relative contributions of island characteristics, marine subsidies, species traits, and species interactions on avian community composition.LocationCentral Coast region of British Columbia, Canada.TaxonTerrestrial breeding birds.MethodsWe observed 3610 individuals of 32 bird species on 89 islands that spanned multiple orders of magnitude in area (0.0002–3 km2). We fit a spatially explicit joint species distribution model to estimate the relative contributions of island physical characteristics, island‐specific inputs of marine subsidies, species' traits, and biotic interactions on species distributions. Biogeographic characteristics included island area, isolation, and habitat heterogeneity, while marine influence was represented by forest‐edge soil δ15N, wrack biomass, shoreline substrate, and distance to shore. This approach also allowed us to estimate how much variation in distributions resulted from species' biological traits (i.e. body mass, feeding guild, feeding height, and nesting height).ResultsBird species distributions were determined almost equivalently by island biogeographic characteristics (23.5% of variation explained) and marine influence (24.8%). We detected variation in species‐specific responses to both island biogeographic characteristics and marine influence, but no significant effect of any biological trait examined. Additionally, we found evidence that habitat preferences were a more important driver than competitive interactions.Main ConclusionsAlthough most island biogeographic studies focus only on islands' physical characteristics, we found evidence for an equivalent role of marine subsidy in structuring island bird communities. Our study suggests that for small islands, disentangling the effects of island biogeographic characteristics, marine inputs, and biotic interactions is a useful next step in understanding species distributions.

Applying community assembly theory to restoration: overcoming dispersal and abiotic filters is key to diversifying California grassland

Ecologists have explored community assembly through the framework of ecological filters, which predicts that species must overcome a series of challenges (i.e. pass through “filters”) to successfully establish in a given community. In the context of restoration, these filters (dispersal, abiotic, and biotic) can be manipulated to alter the resulting plant community by favoring native species or disadvantaging non‐native invasive species. We conducted two studies manipulating assembly filters at two California grassland sites previously dominated by non‐native species. At Site 1, we explored how variations in sequential seeding of native grasses and forbs (to overcome dispersal and biotic filters caused by priority effects) influenced the resulting community. At Site 2, we explored how thatch removal (to overcome the abiotic filter of light limitation) and herbicide‐based weed control (to overcome the biotic filter of competition from non‐native species) influenced the addition of native forbs into a partially restored grassland. Native forbs at Site 1 did not suffer from arriving after grasses, but native grasses benefited when given 1 year priority over forbs. At Site 2, dethatching increased native forb cover in a high rainfall year. Herbicide application reduced non‐native grass cover in dethatched plots without negatively affecting native cover. Native forb and grass cover were significant predictors of non‐native grass cover. However, they accounted for only 29% of the variation observed, suggesting there are other influential factors not considered in this study. Our results suggest that forbs can be incorporated into established native grasslands more successfully after dethatching.

Ecomorphological groups in oribatid mite communities shift with time after topsoil removal – Insight from multi-trait approaches during succession in restored heathlands

Restoration of nutrient-enriched heathlands and similar dry habitats via topsoil removal requires the re-assembly of above and belowground communities to attain fully functional ecosystems. Top-soil removal provides unique opportunities to study the assembly processes, but research has traditionally focused on succession of the aboveground part of the ecosystem. Oribatid mites are a dominant group of soil mesofauna in the belowground part of heathlands. They possess attributes for bioindication and have shown high sensitivity to environmental changes during succession. However, few studies have focused on changes in functional community profiles and the factors shaping them with time. We sampled heathlands of different restoration ages located in East Belgium, studied traits of oribatid mite communities of a chronosequence, and assessed the interaction between traits and abiotic variables using community weighted means (CWM) and an iterative co-correlation analysis between abiotic parameters, species trait attributes and species abundances (iterative RLQ analysis). Our study suggests that moisture preferences, concealability (i.e. defence mechanism against desiccation and predation), and body length were the dominant traits structuring the oribatid mite communities. We found that both dispersal and environmental filters shape the assembly of oribatid mite communities, but these drivers dominate different stages of succession. Moreover, trait assemblages deriving from three well-defined eco-morphological groups closely followed these constraints in time. Thus, the shifting dominance of specific groups provides valuable insight on the soil community functioning in a changing environment.

Soil fertility and landscape surrounding former arable fields drive the ecological resilience of Mediterranean dry grassland plant communities

IntroductionSemi-natural dry grasslands are among the species-richest and most diverse habitats in Europe especially in the Mediterranean Basin. They evolved with long-term severe environmental constraints, either biotic (e.g., grazing or mowing) or abiotic (e.g., dryness or oligotrophy). Their recovery after sever anthropogenic disturbance, such as cultivation is often very slow and incomplete. A deeper understanding of the processes driving the recovery would be of great benefit to better restore or conserve these grasslands. We used the filter model as a framework to assess the relative importance of dispersion, abiotic and biotic filters as drivers of this recovery.MethodsWe studied the medium-term dynamics of 37 Mediterranean dry grassland plant communities after an episode of cultivation in the plain of La Crau (Southern France) by two census: after 25 years of abandonment, and revisited 10 years later (35 years of abandonment). Our aims were to characterize the temporal medium-term dynamics of these communities, to measure their taxonomic resilience and to identify the drivers. We performed structural equation modeling to measure the importance of the various drivers, with cover of remnant dry grasslands surrounding each studied community as a proxy for the dispersion filter, soil pH and phosphorus content as proxies for the abiotic filter and cover of the most dominant species as a proxy for the biotic filter.Results and DiscussionOur results show that former arable field vegetation do not recover after more than 40 years. The three filters drive the recovery of dry grassland vegetation: former arable fields that have lower phosphorus content (abiotic filter) have a lower cover of dominant species (biotic filter), a higher species richness and a higher similarity with remnant dry grassland plant communities, especially if the former arable fields are surrounded by remnant dry grasslands (dispersion filter).

Noise suppression of FMCW lidar

Aiming at the problem that the ranging accuracy of the frequency-modulated continuous wave (FMCW) lidar decreases in the strong noise environment, experiments are carried out to verify the feasibility of the Faraday anomalous dispersion filter (FADOF) in the FMCW lidar system. The transmitter of the system uses the potassium atom vapor cell to stabilize the frequency and uses the field programmable gate array (FPGA) as the servo system. K-FADOF is used to suppress the additive noise at the receiving end of the lidar system. The results of this experiment show that the use of FADOF can successfully eliminate the interference of noise at the receiver. This experiment verifies the effectiveness of FADOF in suppressing noise in the field of FMCW lidar.

In-syringe dispersive solid phase filter extraction cleanup followed by liquid chromatography-triple quadrupole mass spectrometry for fast determination of colchicine in plasma/urine

As an effective treatment for acute gouty arthritis and cardiovascular disease, colchicine is also a toxic alkaloid and may cause poisoning or even death in overdose. The study of colchicine elimination and the diagnosis of poisoning etiology need the rapid and accurate quantitative analysis method in biological matrix. An analytical method was developed for colchicine in plasma and urine by in-syringe dispersive solid phase extraction (DSPE) followed by liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). Sample extraction and protein precipitation were proceeded with acetonitrile. The extract was cleaned by in-syringe DSPE. An XBridge™ BEH C18 column（100 mm × 2.1 mm, 2.5 µm）was used to separate colchicine by gradient elution with mobile phase of 0.01% (v/v) ammonia-methanol. The amount and filling sequence of magnesium sulfate (MgSO4) and primary secondary amine (PSA) suitable for in-syringe DSPE were studied. Scopolamine was screened as the quantitative internal standard (IS) for colchicine analysis according to the consistency of recovery rate, chromatographic retention time and matrix effects. The limits of detection for colchicine in plasma and urine were both 0.06 ng mL−1 and the limits of quantitation were both 0.2 ng mL−1. The linear range was 0.04 – 20 ng mL−1 (Equivalent to 0.2–100 ng mL−1 in plasma or urine) with a correlation coefficient r > 0.999. By IS calibration, the average recoveries at three spiking levels in plasma and urine were 95.3–102.68% and 93.9–94.8% with the relative standard deviations (RSDs) of 2.9–5.7% and 2.3–3.4%, respectively. The matrix effects, stability, dilution effects and carryover for determination of colchicine in plasma and urine were also evaluated. The elimination of colchicine within 72–384 h post-ingestion was studied for a poisoning patient with the doses of 1 mg d−1 for 39 days and then 3 mg d−1 for 15 days).

Taxon-dependent effects of dispersal limitation versus environmental filters on bryophyte assemblages-Multiple perspective studies in land-bridge islands.

To explore the taxon-dependent contribution of dispersal limitation versus environmental filters to bryophyte assemblages. We investigated bryophytes and six environmental variables on 168 islands in the Thousand Island Lake,China. We compared the observed beta diversity with the expected values based on six null models (EE, EF, FE, FF, PE, and PF), detected the partial correlation of beta diversity with geographical distances. We quantified the contributions of spatial versus environmental variables and island isolation per se to species composition (SC) using variance partitioning. We modeled the species-area relationships (SARs) for bryophytes and the other eight biotas. To explore the taxon-dependent effects of spatial versus environmental filters on bryophytes, 16 taxa including five categories (total bryophytes, total mosses, liverworts, acrocarpous, and pleurocarpous mosses) and 11 species-richest families were included in the analyses. The observed beta diversity values were significantly different from the predicted values for all 16 taxa. For all five categories, the observed partial correlations between beta diversity and geographical distance after controlling environmental effects were not only positive, but also significantly different from the predicted values based on the null models. Spatial eigenvectors are more important in shaping SC than environmental variables for all 16 taxa except Brachytheciaceae and Anomodontaceae. Spatial eigenvectors contributed more to SC variation in liverworts than in mosses and in pleurocarpous mosses than in acrocarpous mosses. The effects of island isolation on SC were significant for all five categories, highly varied at the family level. The z values of the SARs for the five bryophyte categories were all larger than those of the other eight biotas. In subtropical fragmented forests, dispersal limitation exerted significant, taxon-dependent effects on bryophyte assemblages. It was dispersal limitation rather than environmental filtering that predominantly regulated the SC patterns of bryophytes.

Environmental Filtering Drives Fungal Phyllosphere Community in Regional Agricultural Landscapes.

To adapt to climate change, several agricultural strategies are currently being explored, including a shift in land use areas. Regional differences in microbiome composition and associated phytopathogens need to be considered. However, most empirical studies on differences in the crop microbiome focused on soil communities, with insufficient attention to the phyllosphere. In this study, we focused on wheat ears in three regions in northeastern Germany (Magdeburger Börde (MBB), Müncheberger Sander (MSA), Uckermärkisches Hügelland (UKH)) with different yield potentials, soil, and climatic conditions. To gain insight into the fungal community at different sites, we used a metabarcoding approach (ITS-NGS). Further, we examined the diversity and abundance of Fusarium and Alternaria using culture-dependent and culture-independent techniques. For each region, the prevalence of different orders rich in phytopathogenic fungi was determined: Sporidiobolales in MBB, Capnodiales and Pleosporales in MSA, and Hypocreales in UKH were identified as taxonomic biomarkers. Additionally, F. graminearum was found predominantly in UKH, whereas F. poae was more abundant in the other two regions. Environmental filters seem to be strong drivers of these differences, but we also discuss the possible effects of dispersal and interaction filters. Our results can guide shifting cultivation regions to be selected in the future concerning their phytopathogenic infection potential.

Phylogenetic divergence and population genetics of the hydrothermal vent annelid genus Hesiolyra along the East Pacific Rise: Reappraisal using multi‐locus data

AbstractAimMaintaining genetic connectivity is crucial for species that inhabit the disjunct and unstable deep‐sea hydrothermal vents. We aimed to re‐assess the connectivity of the annelid genus Hesiolyra distributed at hydrothermal vents along the East Pacific Rise (EPR). A previous study detected a major clade among five Hesiolyra populations spanning from 13°N to 21°S and a minor sympatric southern clade with ~1% divergence from the major clade. However, this study was based on a short locus of 366‐bp COI gene, which might not contain sufficient informative sites.LocationEast Pacific Rise.MethodsWe sequenced 188 specimens of Hesiolyra from five hydrothermal vent fields along the East Pacific Rise for six mitochondrial and two nuclear loci to infer their genetic divergence, population diversity and gene flow.ResultsWe found a minor southern clade (Hesiolyra aff. bergi) which was genetically distinct from Hesiolyra bergi sensu stricto for all gene markers explored except 16S. We also found shared genotypes between H. bergi and H. aff. bergi likely resulted from incomplete lineage sorting. For H. bergi s.s., we found a low but fixed divergence between the north and south EPR populations. We estimated the northern and southern metapopulations of H. bergi s.s. split ~0.45 Mya (HPD: 0.27–0.74 Mya). The northern metapopulation had a higher haplotype diversity than the southern metapopulation, indicating historical gene flow and loss of genetic diversity in the southern clade.Main conclusionsWe confirmed that the equatorial dispersal filter observed previously on several other vent species also applies to H. bergi. Our results highlight the power of the multi‐locus approach in revealing the divergence and population genetic history of marine species with strong dispersal capabilities, indicating that the NEPR and the SEPR should be considered as separate biogeographic regions in environmental management and biological conservation.

Plant community assembly is jointly shaped by environmental and dispersal filtering along elevation gradients in a semiarid area, China.

Environmental filtering (EF) and dispersal filtering (DF) are widely known to shape plant community assembly. Particularly in arid and semi-arid mountainous regions, however, it remains unclear whether EF or DF dominate in the community assembly of different life forms or how they interact along elevational gradients. This research aims to reveal how different ecological processes influence herbaceous and woody community assembly and how they respond to various environmental drivers and elevational gradients. Here we integrated taxonomic diversity (TD), phylogenetic diversity (PD), and ecological drivers across an elevational gradient of 1,420 m in the Helan Mountain Nature Reserve, in typical arid and semi-arid areas of China. This study showed that the TD and PD of herbaceous communities significantly increase linearly with changing elevation gradients, while woody 'TD' showed a unimodal pattern, and there was little relationship between woody 'PD' and elevation. Herbaceous species exhibited significant phylogenetic clustering at low elevations, where they were influenced by climate, aspect, and tree cover. However, woody species exhibited random patterns across elevations. Herbaceous and woody species' taxonomic and phylogenetic beta diversity is governed primarily by spatial turnover rather than nestedness. Spatial turnover is caused primarily by EF and DF's combined influence, but their relative importance differs between herbaceous and woody communities. Therefore, we conclude that the responses of herbaceous and woody plants along elevation gradients in the Helan Mountains are decoupled due to their different adaptation strategies to climate factors in the drylands. These findings are important for understanding the assembly mechanisms driving plant communities in dryland under the context of dramatic increases in drought driven by climate warming.

Aerobiology over the Southern Ocean - Implications for bacterial colonization of Antarctica.

Parts of the Antarctic are experiencing dramatic ecosystem change due to rapid and record warming, which may weaken biogeographic boundaries and modify dispersal barriers, increasing the risk of biological invasions. In this study, we collected air samples from 100 locations around the Southern Ocean to analyze bacterial biodiversity in the circumpolar air around the Antarctic continent, as understanding dispersal processes is paramount to assessing the risks of microbiological invasions. We also compared the Southern Ocean air bacterial biodiversity to non-polar ecosystems to identify the potential origin of these Southern Ocean air microorganisms. The bacterial diversity in the air had both local and global origins and presented low richness overall but high heterogeneity, compatible with a scenario whereby samples are composed of a suite of different species in very low relative abundances. Only 4% of Amplicon Sequence Variants (ASVs) were identified in both polar and non-polar air masses, suggesting that the polar air mass over the Southern Ocean can act as a selective dispersal filter. Furthermore, both microbial diversity and community structure both varied significantly with meteorological data, suggesting that regional bacterial biodiversity could be sensitive to changes in weather conditions, potentially altering the existing pattern of microbial deposition in the Antarctic.

Spatial assortment of soil organisms supports the size-plasticity hypothesis

The size-plasticity hypothesis posits that larger size organisms are less plastic in their metabolic rates and, therefore, are more strongly environmental-filtered than smaller organisms. Many studies have supported this hypothesis by evaluating the relative roles of environmental filtration and dispersal for different taxonomic groups of soil organisms. Most observations are made at large spatial scales, which are assumed to have a wide array of varying habitats. However, since urbanization causes habitat fragmentation at smaller regional scales, testing the size-plasticity hypothesis at this scale would help better understand the spatial assortment of urban soil organisms which, in turn, would help to develop improved management and conservation strategies for urban soil health. Here, we used DNA metabarcoding on five groups of soil biota (bacteria, fungi, protists, nematodes, and invertebrates) to assess the relative importance of dispersal and environmental filters to examine the size-plasticity hypothesis at this spatial scale in an urban environment. We observed strong distance-decay of community similarities associated with higher levels of stochastic changes in bacteria, nematode, and protist communities but not fungal or invertebrate communities. Bacterial communities occupied the widest niche followed by protists and nematodes, potentially because of their higher dispersal abilities compared to the larger soil organisms. Null deviation of communities varied with taxonomic groups where bacteria and nematodes were mainly driven by homogenizing dispersal, protists and fungi by drift, and soil invertebrates by environmental selection. We further identified a small percentage of locally-adapted taxa (2.1%) that could be focal taxa for conservation and restoration efforts by, for example, restoring their habitats and enhancing their regional connectivity. These results support the size-plasticity hypothesis at the relatively unexplored regional scale in an urbanization context, and provide new information for improving urban soil health and sustainable city models.

Species‐rich plant communities in interior habitats of small forest fragments: The role of seed dispersal and edge effect

AbstractQuestionsWhat are the effects of environmental and dispersal filters on vegetation in small and species‐rich fragments of temperate forests in which species richness increases along the edge–interior gradient?LocationSmall fragments of thermophilic forests in central Bohemia, Czech Republic.MethodsRepeated vegetation surveys and seed rain samplings were conducted in 71 plots located in 17 forest fragments (0.4 to 255 ha) in an agricultural landscape in Central Europe. A subsequent assessment of seed viability was performed via germination in a greenhouse. We evaluated species richness, composition and the similarities between forest vegetation and viable available seeds, accounting for potentially significant environmental conditions. Particularly, we examined the effects of species with different associations to the forest environment in combination with prevalent dispersal strategies.ResultsSpecies richness and composition of the herb layer vegetation (including tree and shrub seedlings) in small forest fragments reflected seed distribution and, to a lesser extent, seed viability. Plant species composition showed a nested pattern according to the distance from the forest edge; the species at the edge represented a subset of the species in the forest interior. Forest specialist species with spatially limited dispersal consistently achieved the highest species richness in forest interiors (&gt;200 m from the forest edge), although this differed depending on aspect. Species richness of generalists and open‐land species benefitted from higher light quality and vice versa for forest specialists.ConclusionsSmall forest fragments maintain species‐rich herb layer communities confined in area‐limited interior habitats. They do this despite being mostly or entirely under the influence of the edge effect and impoverished of forest specialists. Moreover, the species‐rich interiors of the small forest fragments are likely prone to negative changes in species composition induced either by canopy closure or opening in the future.

Novel molecularly imprinted phenolic resin–dispersive filter extraction for rapid determination of perfluorooctanoic acid and perfluorooctane sulfonate in milk

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are emerging pollutants that threaten food safety. Herein, a rapid, accurate, and selective method for determination of PFOA and PFOS in milk was established by using new molecularly imprinted phenolic resin (MIP-PR) as the adsorbent of dispersive filter extraction (DFE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). MIP-PR was synthesized at room-temperature using m-aminophenol, glutaraldehyde, and perfluorononanoic acid as the monomers, cross-linkers, and virtual templates, respectively, and exhibited rapid mass transfer (30 s), high selectivity (imprinted factors > 3.7), and large adsorption capacity (>54.6 mg/g). Compared with reported methods, the developed MIP-PR–DFE method is fast, selective, inexpensive, and shows good purification and enrichment efficiency. The proposed MIP-PR–DFE–LC-MS/MS exhibited low limits of detection (0.006–0.022 ng/mL), high recoveries (94.7–109 %), and good precision (RSDs ≤ 9.5 %). This study provides a new idea for the development of imprinted resin adsorbents for perfluorinated compound, and a new method for sample pretreatment for monitoring of PFOA and PFOS in food.

Ultrashort near-infrared pulse generation by non-collinear optical parametric amplification in LiInS2

We demonstrate non-collinear optical parametric amplification (NOPA) in LiInS2 to generate ultrashort near-infrared pulses. White light pulses around 1400 nm generated in yttrium aluminum garnet are amplified by five orders of magnitude up to 1.0 µJ by three-stage NOPA in LiInS2. The dispersion of the amplified pulses is compensated by an acousto-optic programmable dispersive filter, resulting in the pulse compression down to 40 fs, which is 1.1 times the pulse width of the Fourier-transform limited pulse. The successful demonstration of NOPA in LiInS2 indicates the possibility as a new light source to obtain high peak intensity which enables us to access the regime of non-perturbative physics.

ZIF-8@SiO2 based novel dispersive solid-phase filter extraction technique for the purification of laminarin and fucoidan from undaria pinnatifida

Laminarin and fucoidan belong to seaweed polysaccharides, which are abundant in kelp, such as undaria pinnatifida, and have a variety of beneficial pharmacological activities. This study developed a dispersive solid-phase filter extraction (DSPFE) method by combining the high mass transfer efficiency of traditional dispersive solid-phase extraction (DSPE) with the timesaving and convenient advantages of filter solid-phase extraction (FSPE). Although the surface interactions enable ZIF-8 to separate large molecules, the small particle size of ZIF-8 generates ultrahigh pressures during solid-phase extraction (SPE). Hence, a large particle size of ZIF-8@SiO2 can be obtained by growing ZIF-8 on SiO2. Using ZIF-8@SiO2 as the adsorbent for DSPFE combined with high-performance size exclusion chromatography (HPSEC), the conditions of vortex-assisted DSPFE were optimized to realize the economic (adsorbent amount: 5 mg), rapid (extraction time: 10 min), and efficient (recovery: 88.5–91.1%) extraction and analysis of laminarin and fucoidan in undaria pinnatifida. The adsorption process followed Freundlich isotherm (R2 ≥ 0.9792) and pseudo-second-order kinetics (R2 ≥ 0.9870). The proposed method showed good linearity (0.01–2 mg/mL, R2 ≥ 0.9990), limit of detection (0.027–0.114 mg/mL), limit of quantitation (0.089–0.379 mg/mL), accuracy (93.4–104.7%), and precision (2.2–5.6%).