Variation In Composition Research Articles

Effect of gastrointestinal digestion on the stability, antioxidant activity, and Caco-2 cellular transport of pigmented grain polyphenols.

Grain polyphenols are known to possess several health properties. However, their digestive stability and intestinal absorption have not been fully elucidated. This study investigated the fate of pigmented grain polyphenols in the digestive system. Purple rice, purple barley, purple wheat, and blue wheat extracts were subjected to simulated gastric and intestinal phase digestion, followed by Caco-2 cellular transport. Phenolic profiling and antioxidant activity were determined using benchtop assays and an ultra-high-performance liquid chromatography-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid free radical) (UHPLC-ABTS•+) system. The results demonstrated a decrease in the total phenolic content of extracts after digestion, with purple rice extract retaining the highest phenolic content (79%) and ABTS•+antioxidant activity (31%). Antioxidant activity was retained the most during the gastric phase; however, dominant antioxidant compounds were not detected after intestinal digestion. Significant variations in phenolic composition and radical scavenging activity were detected after digestion. Protocatechuic acid, vanillic acid, apigenin, and chrysoeriol were all transported across the intestinal barrier. The findings of this study provide novel insights into the in vitro stability and antioxidant activity of cereal grain polyphenols after simulated digestion.

Unpredictable Chemical Diversity of Essential Oils in Cinnamomum burmanni (Lauraceae) Living Collections: Beyond Maternally Inherited Phylogenetic Relationships.

The genus Cinnamomum encompasses diverse species with various applications, particularly in traditional medicine and spice production. This study focuses on Cinnamomum burmanni, specifically on a high-D-borneol-content chemotype, known as the Meipian Tree, in Guangdong Province, South China. This research explores essential oil diversity, chemotypes, and chloroplast genomic diversity among 28 C. burmanni samples collected from botanical gardens. Essential oils were analyzed, and chemotypes classified using GC-MS and statistical methods. Plastome assembly and phylogenetic analysis were conducted to reveal genetic relationships. Results showed distinct chemotypes, including eucalyptol and borneol types, with notable variations in essential oil composition. The chloroplast genome exhibited conserved features, with phylogenetic analysis revealing three major clades. Borneol-rich individuals in clade II suggested a potential maternal inheritance pattern. However, phylogenetic signals revealed that the composition of essential oils is weakly correlated with plastome phylogeny. The study underscores the importance of botanical gardens in preserving genetic and chemical diversity, offering insights for sustainable resource utilization and selective breeding of high-yield mother plants of C. burmanni.

Temporal variations of stable isotopic compositions in atmospheric water vapor on the Southeastern Tibetan Plateau and their controlling factors

Stable isotopic compositions in atmospheric water vapor (δ18OV, δDV and d-excessV) are effective tracers that provide new insights into the local and regional hydrological cycle on the Tibetan Plateau. One-year continuous measurements of the isotopic compositions in near-surface atmospheric water vapor on the Southeastern Tibetan Plateau are reported. Our results demonstrated the relative impacts of moisture source shifts, large scale moisture transport, and local processes on the variability of the isotopic compositions in atmospheric water vapor. The observed seasonal variations in δ18OV and d-excessV exhibit low values in the monsoon period and high values in the non-monsoon period due to the predominance of large-scale atmospheric circulations. Local processes significantly modulate diurnal cycles of δ18OV and d-excessV. The sharp decrease in δ18OV and increase in d-excessV is related to the synoptic process. Moreover, the seasonality of moisture sources and transport, including moisture uptake and upstream rainout strongly affects the atmospheric moisture and the isotopes. These findings will improve our understanding of the regional hydrological cycle on the Southeastern Tibetan Plateau and provide reference to validate the simulated stable water isotopes.

Effect of Mesoporous Silica as a Solid Precursor on the Properties of Silicon Oxycarbide Thin Films via Hot Filament Chemical Vapor Deposition

AbstractThis study investigates the impact of mesoporous silica tablets on the synthesis and properties of silicon oxycarbide thin films produced via Hot Filament Chemical Vapor Deposition. Results reveal significant variations in composition and cluster morphology, influenced by the introduction of mesoporous silica tablets. The study demonstrates controlled deposition, consistent synthesis, and the substantial impact of mesoporous silica tablets on the composition, structure, and optical properties of thin films. These findings offer new possibilities for tailor design applications in electronics, optics, and sensors.

Assessing Radiation Effects on Chemo-Treated BT20 and 4T1 Breast Cancer, and Neuroblastoma Cell Lines: A Study of Single and Multiple-Cell Ionization via Infrared Laser Trapping

Background: Our study aimed to assess the radiation sensitivity of BT20, a human breast tumor cell line, using the laser-trapping technique and compare it with N2a and 4T1 cells. Additionally, we investigated the impact of the antitumor compound 2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) on radiation sensitivity. Methods and Materials: We employed laser trapping to calculate both the threshold ionization energy (TIE) and threshold radiation dose (TRD) for BT20, N2a, and 4T1 cells. We assessed the effect of DMDD on BT20 cells’ radiosensitivity and conducted comparisons across these cell lines. Results: Our findings reveal that DMDD significantly enhances the radiosensitivity of BT20 breast carcinoma cells. Moreover, we observed distinct trends in TIE and TRD across the three cell lines, with differences attributed to variations in cell size and composition. When multiple cell ionizations were considered, a notable reduction in TRD was observed, implicating factors such as the chain effect of ionizing radiation and the influence of DMDD. The study found that TIE increased with the number of cells in the trap while TRD consistently decreased across all three cell lines, suggesting comparable radiation sensitivity, and oligostilbene treatment further reduced TRD, presenting the potential for enhancing therapeutic ratios in cancer treatment. Conclusion: The antitumor compound DMDD enhances the radiosensitivity of BT20 breast carcinoma cells, highlighting its potential in cancer treatment. Furthermore, our study underscores the impact of cell size and multiple-cell ionizations on TRD. Leveraging laser trapping techniques, biocompatible nanoparticles, and advanced optical tweezers opens promising avenues for personalized and effective cancer therapy approaches.

Spatial variation in the rocky temperate benthic mesophotic communities of the Wellington region in New Zealand

ABSTRACT Temperate mesophotic ecosystems (TMEs) have only recently been recognised as distinct ecosystems and generally occur between 30 and 150 m at the limit of photosynthetic light penetration. In this study, we surveyed the benthic communities inhabiting rocky deep-water features in two regions at the south of New Zealand’s North Island to assess small (1–2 km) and larger (10–100 km) scale variation in the benthic communities they support: the Wellington South Coast (WSC) and the Kāpiti Coast (KC). We deployed Remotely Operated Vehicles at seventeen sites, three on the WSC and 14 on the KC, covering a depth range of 26 to 72 m. There was significant variation in the benthic community composition between sites, at both spatial scales, and with depth. Across all sites, sponges and bryozoans were by far the most abundant organisms, covering around 30% of the substrate, with all other groups having <5% cover. The sponges and bryozoans created complex three-dimensional structure on the seafloor, providing habitat and refuge for other mobile organisms. Our work provides an important baseline against which any future changes can be compared and will support future spatial management in this region.

Temporal dynamics of invertebrate community assembly in Lake Victoria since the late Pleistocene based on chitinous remains

Abstract Preserved assemblages of invertebrate remains in lacustrine sediment reveal temporal variations of community composition and environmental conditions. However, records for large tropical lakes are scarce. Lake Victoria, the largest tropical lake, has a dynamic history of changes in water level, biogeochemistry and fish community composition over the past ~17,000 cal yr BP. In order to quantify changes in the invertebrate assemblage of Lake Victoria from the late Pleistocene throughout the Holocene, we examined chitinous remains of Cladocera and larval dipterans (Chironomidae and Chaoboridae) from a sediment core (37 m water depth) dated from ~13,700 cal yr BP to present. We identified four major phases in the invertebrate assemblage throughout this period of lake history. Firstly, Chironomidae and Chaoboridae appeared at low abundances during the earliest stages of lake inundation in the late Pleistocene, at a time when Cladocera were notably absent. Secondly, chaoborids and chironomids increased in abundance during the mid‐Holocene, which coincided with high diatom production toward the end of the Holocene African Humid Period. Thirdly, starting ~4,700 cal yr BP, Alona, a predominantly littoral cladoceran genus, consistently appeared in the invertebrate assemblage alongside changes in mixing regimes and persisted throughout the late Holocene to the present. Fourthly, the arrival of both Chydorus and Bosmina longirostris marked the establishment of an abundant cladoceran assemblage at ~1,350 cal yr BP. The assemblage then gradually shifted toward the increasing dominance of B. longirostris, a planktonic cladoceran. Several of the observed changes in the invertebrate assemblage occurred concurrently with changes in climatic conditions in East Africa and diatom productivity that have been previously recorded in Lake Victoria. This multi‐millennial record of sedimentary invertebrate assemblages in Lake Victoria elucidates some of the temporal development of these communities throughout most of the dynamic modern history of the ecosystem.

Spatiotemporal distribution patterns of soil ciliate communities in the middle reaches of the Yarlung Zangbo River

Introduction: Soil ciliates, as protozoa, play a crucial role in biogeochemical cycling and the soil food web, yet they are highly sensitive to environmental fluctuations in soil conditions. The diversity and biogeographic characteristics of soil ciliates in the Tibetan Plateau remain poorly understood. As part of a regional survey focused on soil ciliate diversity, we investigated the composition and spatiotemporal variations of soil ciliate communities along the Yarlung Zangbo River, a representative soil habitat in the Tibetan Plateau.Methods: A total of 290 soil samples were collected from four habitat types of grassland, shrubland, forestland and wetland in the middle reaches of the Yarlung Zangbo River during the wet and dry seasons, and 138 species of ciliates were identified.Results: Soil ciliate diversity exhibited greater variation across habitat types than seasons. Moreover, soil ciliate diversity was higher during the wet season compared to the dry season, with the wetland habitat showing the highest diversity and the grassland habitat displaying the lowest. We observed spatiotemporal heterogeneity in the composition of soil ciliate communities across different seasons and habitat types. Notably, Litostomatea, Karyorelictea, and Prostomatea predominated in ciliate communities during the wet season and in grassland habitat. Phyllopharyngers dominated during dry seasons and in forested regions, while Spirotrichea species were prevalent in wetland and forested areas. The co-occurrence network analysis showed that soil ciliate community was more complex in wet season than in dry season, and the stability of soil ciliate community in wet season was higher than that in dry season. The stability of soil ciliate community in wetland was higher than that in forestland, shrubland and grassland, and the anti-interference ability was stronger. Soil temperature (ST), Total nitrogen (TN), Soil organic matter (SOM) and Soil water content (SWC) are important factors affecting the structure of soil ciliate community. By influencing the metabolic rate and nutrient acquisition of soil ciliates, the distribution pattern of soil ciliate community diversity in the middle reaches of Yarlung Zangbo River is shaped.Discussion: In summary, this study revealed the distribution pattern of soil ciliate community diversity in the Yarlung Zangbo River Basin, and the key factors affecting the spatial and temporal differences and stability of the community, enhancing our understanding of how ciliates adapt to environmental conditions in soil habitats across the Tibetan Plateau.

The Impact of Marangoni and Buoyancy Convections on Flow and Segregation Patterns during the Solidification of Fe-0.82wt%C Steel.

Due to the high computational costs of the Eulerian multiphase model, which solves the conservation equations for each considered phase, a two-phase mixture model is proposed to reduce these costs in the current study. Only one single equation for each the momentum and enthalpy equations has to be solved for the mixture phase. The Navier-Stokes and energy equations were solved using the 3D finite volume method. The model was used to simulate the liquid-solid phase transformation of a Fe-0.82wt%C steel alloy under the effect of both thermocapillary and buoyancy convections. The alloy was cooled in a rectangular ingot (100 × 100 × 10 mm3) from the bottom cold surface to the top hot free surface by applying a heat transfer coefficient of h = 600 W/m2/K, which allows for heat exchange with the outer medium. The purpose of this work is to study the effect of the surface tension on the flow and segregation patterns. The results before solidification show that Marangoni flow was formed at the free surface of the molten alloy, extending into the liquid depth and creating polygonized hexagonal patterns. The size and the number of these hexagons were found to be dependent on the Marangoni number, where the number of convective cells increases with the increase in the Marangoni number. During solidification, the solid front grew in a concave morphology, as the centers of the cells were hotter; a macro-segregation pattern with hexagonal cells was formed, which was analogous to the hexagonal flow cells generated by the Marangoni effect. After full solidification, the segregation was found to be in perfect hexagonal shapes with a strong compositional variation at the free surface. This study illuminates the crucial role of surface-tension-driven Marangoni flow in producing hexagonal patterns before and during the solidification process and provides valuable insights into the complex interplay between the Marangoni flow, buoyancy convection, and solidification phenomena.

Seasonal variation and human impacts of the river biofilm bacterial communities in the Shiting River in southeastern China.

Bacterial communities in epilithic biofilm plays an important role in biogeochemistry processes in freshwater ecosystems. Nevertheless, our understanding of the geographical and seasonal variations of the composition of bacterial communities in the biofilm of gravels on river bed is still limited. Various anthropogenic activities also influence the biofilm bacteria in gravel rivers. By taking the Shiting River in the upper Yangtze River basinin Sichuan Province as an example, we studied the geographical and seasonal variations of epilithic bacteria and the impacts of weirs and other human activities (e.g., sewage pollution). The river has experienced severe degradation since the Ms 8.0 Wenchuan Earthquake, and weirs were constructed to prevent bed erosion.We collected epilithic biofilms samples at 17 sites along ~ 30km river reach of the Shiting River in the autumn of 2021 and the summer of 2022, respectively. We applied 16S rRNA gene high-throughput sequencing technology and Functional Annotation of Prokaryotic Taxa (FAPROTAX) to analyze the seasonal and biogeographic patterns and potential functions of the biofilm bacterial communities. The results showed that epilithic bacteria from the two surveys exhibited variation in community composition, bacterial diversity and potential functions. The bacteria samples collected in the autumn have much higher alpha diversity and richness than those collected in the summer. Bacterial richness and diversity were lower downstream of the weirs than upstream. Low diversity was observed at a sampling site influenced by sewage inflow, which contains high level of nitrogen-related chemicals.

Microbial nutrient limitation along a 2-million-year dune chronosequence

Long-term ecosystem development is characterized by a switch from nitrogen (N) to phosphorus (P) limitation of plant communities as soils age, which leads to changes in plant biomass, diversity, and foliar nutrient concentrations. Similar effects occur belowground, although the extent to which nutrient availability is the primary driver of long-term changes in soil microbial communities remains uncertain. To investigate this, we assessed proxies for soil microbial nutrient limitation along the Jurien Bay dune chronosequence in Western Australia, where a long-term decline in P availability is reflected in strong variation in plant and microbial community composition over 2 million years of soil development. We quantified carbon (C), N, and P in the soil microbial biomass, assayed soil enzymes involved in the acquisition of those nutrients from soil organic matter, and used microbial stoichiometric ratios and vector analysis of enzyme activities to assess whether long-term changes in soil nutrient availability are reflected in nutrient demand by soil microbes. Concentrations of microbial nutrients peaked in Holocene soils (1–6.5 ky), although differences in microbial P were not significant. There were no significant differences in microbial nutrient ratios (C:N, C:P, and N:P) along the chronosequence. Acid phosphatase activity increased continually throughout the chronosequence, while the activities of leucine aminopeptidase and β-glucosidase were greatest in Holocene soils and declined with increasing soil age. Corresponding vector lengths indicated greater investment in C-degrading enzymes in Holocene soils (≤6.5 ky), while vector angles indicated greater investment in the acquisition of P compared with N in Pleistocene soils (≥120 ky). Overall, these findings show that changes in nutrient availability during long-term pedogenesis at Jurien Bay are reflected in microbial investment in nutrient acquisition, but that the soil microbial biomass exhibits a remarkable degree of homeostasis despite major shifts in nutrient availability and community composition over 2 million years of ecosystem development.

Analyzing the Mechanical and Durability Characteristics of Steel Slag-Infused Asphalt Concrete in Roadway Construction

Steel slag is a solid byproduct of the steelmaking process, widely generated in the metallurgical industry. Due to its alkaline nature and excellent adhesive properties with asphalt, it represents a potential road construction material with outstanding road performance, making it well-suited for utilization in highway construction. This paper conducts a systematic analysis of the physical and chemical properties of steel slag, specifically South Steel Electric Furnace slag, and compares it with natural basalt and limestone aggregates. The aim is to establish a foundation for the application of steel slag in asphalt mixtures. Building upon this foundation, we carry out proportioning design for AC-13C and SMA-13 steel slag asphalt mixtures, followed by a comprehensive study of their high-temperature stability, low-temperature stability, water stability, and fatigue performance. Our research reveals variations in the chemical composition of different steel slags, with CaO, SiO2, and Fe2O3 being the primary components. The content of harmful elements varies depending on the steelmaking raw materials and additives used. Notably, the optimum asphalt-to-aggregate ratios for AC-13C and SMA-13 significantly surpass the specified requirements. The freeze–thaw splitting strength ratio and residual stability of steel slag AC-13C and SMA-13 asphalt mixtures exceed the specified requirements, with AC-13C demonstrating the highest water stability, boasting a freeze–thaw splitting strength ratio of 94.07%, and a residual stability of 93.8%. In terms of fatigue characteristics, SMA-13 exhibits a longer fatigue life than AC-13C, indicating superior fatigue performance for steel slag SMA-13. Steel slag enhances the abrasion resistance and rutting resistance of asphalt pavement surface layers, fully meeting the performance requirements for high-grade road surface layers.

Investigation of sensing performances of thick-film resistors sintered on fluorophlogopite glass-ceramic substrates

Strain gauges made of thick-film resistors (TFRs) offer a promising solution for monitoring the structural health of civil engineering projects, owing to their exceptional durability and stability. To address the issue of strain mismatch between alumina substrates and concrete materials, fluorophlogopite glass-ceramic (FGC), which has a low elastic modulus and good machinability, was utilized as a substrate for thick-film resistors. Compatibility between resistor pastes and substrates should be considered, as the substrate can significantly impact the performance of thick-film resistors. TFRs with varying concentrations of RuO2 were screen printed and fired at different temperatures on both FGC and 96% Al2O3 (as a control) substrates. The sheet resistivity, temperature coefficient of resistance (TCR), and gauge factor (GF) of TFRs were evaluated. The strain sensing performances of TFRs on FGC evaluated under compressive loading. The results indicate that TFRs on FGC substrates exhibit higher hot TCRs, lower sheet resistivities, and lower gauge factors than those on Al2O3 substrates under typical firing conditions of 850°C for 10 minutes. As the concentration of RuO2 increases, the differences in properties between TFRs on the two substrates become less pronounced. Microstructural analyses of the interface between the resistor layer and substrate indicate that changes in properties of TFRs on FGC substrates are primarily attributed to variations in RuO2 concentration and glass phase composition, which result from interactions between the resistor layer and FGC substrate. The interaction between the FGC substrate and the resistor layer can be significantly alleviated by lowering the firing temperature from 850°C to 750°C, resulting in TFRs on FGC substrates with properties comparable to those on alumina substrates. The TFRs on FGC exhibit favorable sensitivity, linearity, repeatability, and hysteresis within the input compression strain range of 0–3043με, thus showcasing significant potential for application in structural health monitoring (SHM) in civil engineering.

Unveiling the synergistic effects of pH and Sn content for tuning the catalytic performance of Ni0/NixSny intermetallic compounds dispersed on Ce-Zr mixed oxides in the aqueous phase reforming of ethylene glycol

The product distribution in aqueous phase reforming (APR) of polyols is closely tied to the catalytically induced feed cleavage mechanism. Strategic variations in catalyst composition and synergistic effects prompted by reaction conditions, such as pH, can be utilized to tune the product distribution of both liquid and gaseous phases. This study aimed to compare the physicochemical properties of various NixSny/Ce(Zr)O2 catalysts and their performance in batch tests during the APR of a 6%wt. ethylene glycol (EG) solution under both neutral and alkaline conditions. The results show that the progressive addition of tin strongly tunes the activity of the catalysts and the nickel-induced methanation reaction under neutral conditions, albeit decreasing feed conversions. In synergy with tin tuning, the alkaline environment boosts the process by increasing conversions and H2-yields while still minimizing methanation due to the alkali-induced process of Cannizzaro disproportionation of EG into glycolic acid with subsequent reforming thereof.

VARIATIONS OF δ18О AND δ2H VALUES OF PRECIPITATION IN MOSCOW FROM 2017 TO 2019

To reveal variations in the iso topic composition of O and H in the atmospheric precipitation in Moscow and the processes influencing the isotope composition, all events of precipitation in 2017-2019 were sampled at the Meteorological Observatory of the Moscow State University: 158 samples in 2017, 119 samples in 2018 and 143 samples in 2019. The study is a prolongation of continuous measurements of the isotope composition of precipitation, started by authors in 2014. The study of the isotope composition of precipitation at the MSU Meteorological Observatory was supported by the IAEA and became a part of the Global Network of Isotopes in Precipitation (GNIP) database. It has been found that the intra-annual variability of the isotop e composition of precipitation has a pronounced seasonality. The most isotopically heavy precipitation falls from May to August, and the most isotop ically light precipitation at December-February, mainly due to seasonal air temperature variations. The ratio of the average monthly δ18O values in precipitation and air temperature for the study period varied from 0.34 to 0.39‰/°C, which is consistent with the previously obtained data for precipitation in Moscow. The δ2H-δ18O ratio in precipitation was clos e to that of the Global Meteoric Water Line, pointing to the equilibrium conditions during precipitation formation. It was established that in the summer months isotopic composition is significantly influenced by undercloud evaporation. The deuterium excess va lues in precipitation are not markedly seasonal; however, lower dexc values (below the 3-year average of 11‰) are typical for the summer months (July-August). It is most likely due to undercloud evaporation in conditions of low relative humidity and high air temperatures. Higher dexc values (above 11‰) prevailed from October to April.

Spatiotemporal variations, sources, and atmospheric transformation potential of volatile organic compounds in an industrial zone based on high-resolution measurements in three plants

Industrial emissions are significant sources of volatile organic compounds (VOCs). This study conducted a field campaign at high temporal and spatial resolution to monitor VOCs within three plants in an industrial park in southern China. VOC concentrations showed significant spatial variability in this industrial zone, with median concentrations of 75.22, 40.53, and 29.41 μg/m3 for the total VOCs in the three plants, respectively, with oxygenated VOCs (OVOCs) or aromatics being the major VOCs. Spatial variability within each plant was also significant but VOC-dependent. Seasonal variations in the VOC levels were governed by their industrial emissions, meteorological conditions, and photochemical losses, and they were different for the four groups of VOCs. The temporal and spatial variations in the VOC compositions suggest similar sources of each class of VOCs during different periods of the year in each plant. The diurnal patterns of VOCs (unimodal or bimodal) clearly differed from those at most industrial/urban locations previously, reflecting a dependence on industrial activities. The secondary transformation potential of VOCs also varied temporally and spatially, and aromatics generally made the predominant contributions in this industrial park. The loss rate of OH radicals and ozone formation potential were highly correlated, but the linear relationship substantially changed in summer and autumn due to the intensive emissions of an OVOC species. The lifetime cancer and non-cancer risks via occupational inhalation of the VOCs in the plants were acceptable but merit attention. Taking the secondary transformation potential and health risks into consideration, styrene, xylene, toluene, trichloroethylene, and benzene were proposed to be the priority VOCs regulated in the plants.

The Hirshfeld topological surfaces, volumes, and their voids charge density interplay on radiation shielding properties: A case study of carbide-based ceramics

Transition metal carbides (TMCs) are explored for their potential as radiation shielding materials, with a focus on their γ-ray attenuation properties. These high-density materials, including WC, TaC, HfC, NbC, and VC, are evaluated across an energy range of 0.015–15.0 MeV. Notably, at low incoming photon energy (0.0150 MeV), these TMCs exhibit mass attenuation coefficients (MAC) (TMC, MAC (g/cm2)): (WC, 130.417), (TaC, 125.730), (HfC, 120.873), (NbC, 23.751), and (VC, 32.377) and effective atomic numbers (Zeff) from 22.69 to 73.68. These values surpass those of silicon dioxide (SiO2), highlighting the superior γ-ray attenuation capabilities of TMCs. TMCs exhibit a distinct trend in MAC values, with tungsten carbide (WC) consistently demonstrating the highest MAC values, making it the most efficient γ-ray attenuator. Hafnium carbide (HfC) closely follows, with tantalum carbide (TaC) exhibiting lower MAC values, while niobium carbide (NbC) and vanadium carbide (VC) display the lowest values. These differences can be attributed to variations in material composition and structure. Furthermore, the study delves into the impact of charge density within Hirshfeld voids on LAC values, revealing that as X⁴⁺ … C interactions increase due to higher charge density, LAC values rise. This fine-tuning of topological and charge density distributions within the crystal's voids offers a promising avenue to optimize these materials for enhanced radiation shielding effectiveness. Overall, this research contributes to the understanding of the potential utility of TMCs in radiation shielding applications, showcasing the interplay between crystal structure, composition, and charge distribution as key factors in determining their radiation attenuation capabilities.

Spatiotemporal patterns of microclimatic buffering in relict alpine communities

AbstractQuestionsIn alpine landscapes, topography creates a mosaic of microclimatic niches that might prevent local extinctions, but the influence of this spatial heterogeneity on plant communities is largely unknown. Here we ask (1) how soil microclimatic variation is comparable at temporal and spatial scales, and (2) how such variation influences species composition and local extinctions in relict alpine communities.LocationPicos de Europa National Park, northern Spain.MethodsWe resurveyed permanent plots in four alpine sites following the recording of soil temperatures (temporal survey) for 10 years. We then sampled the spatial variation in species composition and microclimatic temperatures in 80 plots around the permanent plots (spatial survey). We evaluated the variation of six microclimatic indices between the temporal and the spatial surveys, and calculated the temporal trends observed in species cover. We finally predicted local extinction rates under microclimatic scenarios based on the observed microclimate–community relations.ResultsDespite high interannual variation, we found a 10‐year trend of temperature warming on (microridge) fellfields and (microvalley) snowbeds. Microclimatic variation was larger in space than in time, with little temperature variation in snowbeds and extreme low temperatures recorded in fellfields. Species composition was mainly influenced by growing degree days (GDD) and freezing degree days (FDD), which were both related to snow cover duration. Plant cover of 16 species (out of 36 frequent species) showed significant responses to microclimatic variation. Local extinctions were mainly predicted under relatively hotter and more freezing conditions.ConclusionsOur results support the idea that microclimatic spatial heterogeneity can reduce the negative influence of climate change on alpine plant communities. However, a continuous reduction of snow cover will result in a tipping point beyond which the buffer effect of this spatial heterogeneity will not be effective in protected microsites, leading to community homogenization. This process may have started in relict alpine communities where species from snowy microclimates are being outcompeted by species adapted to below‐zero winter temperatures.

Geographical distribution and species variation of gut microbiota in small rodents from the agro-pastoral transition ecotone in northern China.

The gut microbiota of rodents is essential for survival and adaptation and is susceptible to various factors, ranging from environmental conditions to genetic predispositions. Nevertheless, few comparative studies have considered the contribution of species identity and geographic spatial distance to variations in the gut microbiota. In this study, a random sampling survey encompassing four rodent species (Apodemus agrarius, Cricetulus barabensis, Tscherskia triton and Rattus norvegicus) was conducted at five sites in northern China's farming-pastoral ecotone. Through a cross-factorial comparison, we aimed to discern whether belonging to the same species or sharing the same capture site predominantly influences the composition of gut microbiota. Notably, the observed variations in microbiome composition among these four rodent species match the host phylogeny at the family level but not at the species level. The gut microbiota of these four rodent species exhibited typical mammalian characteristics, predominantly characterized by the Firmicutes and Bacteroidetes phyla. As the geographic distance between populations increased, the number of shared microbial taxa among conspecific populations decreased. We observed that within a relatively small geographical range, even different species exhibited convergent α-diversity due to their inhabitation within the same environmental microbial pool. In contrast, the composition and structure of the intestinal microbiota in the allopatric populations of A. agrarius demonstrated marked differences, similar to those of C. barabensis. Additionally, geographical environmental elements exhibited significant correlations with diversity indices. Conversely, host-related factors had minimal influence on microbial abundance. Our findings indicated that the similarity of the microbial compositions was not determined primarily by the host species, and the location of the sampling explained a greater amount of variation in the microbial composition, indicating that the local environment played a crucial role in shaping the microbial composition.

The gut microbiome modulates the susceptibility to traumatic stress in a sex-dependent manner.

Post-traumatic stress disorder (PTSD), a psychological condition triggered by exposure to extreme or chronic stressful events, exhibits a sex bias in incidence and clinical manifestations. Emerging research implicates the gut microbiome in the pathogenesis of PTSD and its roles in stress susceptibility. However, it is unclear whether differential gut microbiota contribute to PTSD susceptibility in male and female rats. Here, we utilized the single prolonged stress animal model and employed unsupervised machine learning to classify stressed animals into stress-susceptible subgroups and stress-resilient subgroups. Subsequently, using 16S V3-V4 rDNA sequencing, we investigated the differential gut microbiota alterations between susceptible and resilient individuals in male and female rats. Our findings revealed distinct changes in gut microbiota composition between the sexes at different taxonomic levels. Furthermore, the abundance of Parabacteroides was lower in rats that underwent SPS modeling compared to the control group. In addition, the abundance of Tenericutes in the stress-susceptible subgroup was higher than that in the control group and stress-resilient subgroup, suggesting that Tenericutes may be able to characterize stress susceptibility. What is particularly interesting here is that Cyanobacteria may be particularly associated with anti-anxiety effects in male rats. This study underscores sex-specific variations in gut microbiota composition in response to stress and sex differences should be taken into account when using macrobiotics for neuropsychiatric treatment, highlighting potential targets for PTSD therapeutic interventions.