Effect of chlorination and ultraviolet on the adsorption of pefloxacin on polystyrene and polyvinyl chloride.

During the water treatment process, chlorination and ultraviolet (UV) sterilization can modify microplastics (MPs) and alter their physicochemical properties, causing various changes between MPs and other pollutants. In this study, the impact of chlorination and UV modification on the physicochemical properties of polystyrene (PS) and polyvinyl chloride (PVC) were investigated, and the adsorption behavior of pefloxacin (PEF) before and after modification was examined. The effect of pH, ionic strength, dissolved organic matter, heavy metal ions and other water environmental conditions on adsorption behavior was revealed. The results showed that PS had a higher adsorption capacity of PEF than PVC, and the modification increased the presence of O-containing functional groups in the MPs, thereby enhancing the adsorption capacity of both materials. Chlorination had a more significant impact on the physicochemical properties of MPs compared to UV irradiation within the same time period, leading to better adsorption performance of chlorination. The optimal pH for adsorption was found to be 6, and NaCl, sodium alginate and Cu2+ would inhibit adsorption to varying degrees, among which the inhibition caused by pH was the strongest. Chlorination and UV modification would weaken the inhibitory effect of environmental factors on the adsorption of PEF by MPs. The main mechanisms of adsorption involved electrostatic interaction and hydrogen bonding. The study clarified the effects of modification on the physicochemical properties of MPs, providing reference for subsequent biotoxicity analysis and environmental protection studies.

A review of research on tire burst and vehicle stability control.

Tire burst is an accidental occurrence that poses a serious threat to the driving stability and road safety of vehicles. Therefore, it is of great practical significance to investigate early warning systems for tire burst and develop stability and safety control measures after burst incidents. The development of an accurate model that can effectively represent the impact of tire burst on vehicle dynamics is crucial for the design of control systems and the development of stability control strategies. Most of the existing research on tire burst models is based on static tire tests, the effectiveness of these models still needs to be further verified. The main approach to studying the impact of burst tires on vehicle performance is to embed a burst tire model into a vehicle dynamics model. Understanding the impact of tire burst on vehicle performance is essential for identifying burst incidents and developing stability control strategies. The research on burst identification primarily focuses on early warning systems and estimating vehicle state parameters after burst incidents, while the current research on stability control strategies focuses on enabling vehicles to continue running safely after burst incidents through braking, active steering, and collaborative control. Currently, there is no comprehensive review of research on vehicle tire burst stability control. Therefore, this paper primarily reviews five aspects: (a) the causes and prevention of tire burst, (b) the impact of tire burst on vehicle performance, (c) burst identification, (d) stability control strategies for burst incidents, and (e) future prospects for tire burst research.

Melatonin Attenuates Diabetic Retinopathy by Regulating EndMT of Retinal Vascular Endothelial Cells via Inhibiting the HDAC7/FOXO1/ZEB1 Axis.

Diabetic retinopathy (DR) is characterized as a microvascular disease. Nonproliferative diabetic retinopathy (NPDR) presents with alterations in retinal blood flow and vascular permeability, thickening of the basement membrane, loss of pericytes, and formation of acellular capillaries. Endothelial-mesenchymal transition (EndMT) of retinal microvessels may play a critical role in advancing NPDR. Melatonin, a hormone primarily secreted by the pineal gland, is a promising therapeutic for DR. This study explored the EndMT in retinal microvessels of NPDR and its related mechanisms. The effect of melatonin on the retina of diabetic rats was evaluated by electroretinogram (ERG) and histopathologic slide staining. Furthermore, the effect of melatonin on human retinal microvascular endothelial cells (HRMECs) was detected by EdU incorporation assay, scratch assay, transwell assay, and tube formation test. Techniques such as RNA-sequencing, overexpression or knockdown of target genes, extraction of cytoplasmic and nuclear protein, co-immunoprecipitation (co-IP), and multiplex immunofluorescence facilitated the exploration of the mechanisms involved. Our findings reveal, for the first time, that melatonin attenuates diabetic retinopathy by regulating EndMT of retinal vascular endothelial cells via inhibiting the HDAC7/FOXO1/ZEB1 axis. Collectively, these results suggest that melatonin holds potential as a therapeutic strategy to reduce retinal vascular damage and protect vision in NPDR.

Lifestyle deterioration linked to elevated inflammatory cytokines over a two-month follow-up.

Healthy lifestyle reduces the risk of inflammation-related diseases. This study assessed how lifestyle changes affect inflammatory cytokines over 2 months. Involving 179 apparently healthy participants recruited from community, collecting data on lifestyles (smoking, alcohol, BMI, daily activity, sleep, diet) and measured inflammatory cytokines (TNF-α, IL-1ß, IL-17A, CRP, IL-8, IL-18, IFN-γ) plus pepsinogens (PG I, PG II) at the baseline and 2-month follow-up. The combined adverse lifestyle score is the sum of scores across six lifestyles, with higher scores indicating more adverse lifestyle factors. Use multiple linear regression and mixed linear models to analyze the relationship between the changes in lifestyle and inflammatory cytokines (follow-up values minus baseline values). For every 1-point increase in combined adverse lifestyle score, IL-17A increased by 0.98 (95% CI 0.23, 1.73) pg/mL, IFN-γ increased by 1.79 (95% CI 0.39, 3.18) pg/mL. Decreased changes in daily activity were associated with higher IL-17A (ß = 1.83, 95% CI 0.53, 3.13) and IFN-γ (ß = 2.59, 95% CI 0.9, 4.98). Excluding daily activity, changes in combined adverse lifestyle scores were not associated with changes in inflammatory cytokines. Lifestyle improvements at 2-month intervals may reduce TNF-α, IL-17A and IFN-γ, with daily activity making the greatest contribution.

Histone deacetylases: Regulation of vascular homeostasis via endothelial cells and vascular smooth muscle cells and the role in vascular pathogenesis.

Histone deacetylases (HDACs) are proteases that play a key role in chromosome structural modification and gene expression regulation, and the involvement of HDACs in cancer, the nervous system, and the metabolic and immune system has been well reviewed. Our understanding of the function of HDACs in the vascular system has recently progressed, and a significant variety of HDAC inhibitors have been shown to be effective in the treatment of vascular diseases. However, few reviews have focused on the role of HDACs in the vascular system. In this study, the role of HDACs in the regulation of the vascular system mainly involving endothelial cells and vascular smooth muscle cells was discussed based on recent updates, and the role of HDACs in different vascular pathogenesis was summarized as well. Furthermore, the therapeutic effects and prospects of HDAC inhibitors were also addressed in this review.

A computational mechanistic study on the formation of aryl sulfonyl fluorides via Bi(III) redox-neutral catalysis and further rational design.

Sulfonyl fluorides hold significant importance as highly valued intermediates in chemical biology due to their optimal balance of biocompatibility with both aqueous stability and protein reactivity. The Cornella group introduced a one-pot strategy for synthesizing aryl sulfonyl fluorides via Bi(III) redox-neutral catalysis, which facilitates the transmetallation and direct insertion of SO2 into the BiC(sp2) bond giving the aryl sulfonyl fluorides. We report herein a comprehensive computational investigation of the redox-neutral Bi(III) catalytic mechanism, disclose the critical role of the Bi(III) catalyst and base (i.e., K3PO4), and uncover the origin of SO2 insertion into the Bi(III)C(sp2) bond. The entire catalysis can be characterized via three stages: (i) transmetallation generating the Bi(III)-phenyl intermediate IM3 facilitated by K3PO4. (ii) SO2 insertion into IM3 leading to the formation of Bi(III)-OSOAr intermediate IM5. (iii) IM5 undergoes S(IV)-oxidation yielding the aryl sulfonyl fluoride product 4 and liberating the Bi(III) catalyst for the next catalytic cycle. Each stage is kinetically and thermodynamically feasible. Moreover, we explored other some small molecules (NO2, CO2, H2O, N2O, etc.) insertion reactions mediated by the Bi(III)-complex, and found that NO2 insertions could be easily achieved due to the low insertion barriers (i.e., 17.5 kcal/mol). Based on the detailed mechanistic study, we further rationally designed additional Bi(III) and Sb(III) catalysts, and found that some of which exhibit promising potential for experimental realization due to their low barriers (<16.4 kcal/mol). In this regard, our study contributes significantly to enhancing current Bi(III)-catalytic systems and paving the way for novel Bi(III)-catalyzed aryl sulfonyl fluoride formation reactions.

Monitoring Soil Copper in Urban Land Using Visibale and Near-Infrared Spectroscopy with Spatially Nearby Samples.

Soil heavy metal contamination in urban land can affect biodiversity, ecosystem functions, and the health of city residents. Visible and near-infrared (Vis-NIR) spectroscopy is fast, inexpensive, non-destructive, and environmentally friendly compared to traditional methods of monitoring soil Cu, a common heavy metal found in urban soils. However, there has been limited research on using spatially nearby samples to build the Cu estimation model. Our study aims to investigate how spatially nearby samples influence the Cu estimation model. In our study, we collected 250 topsoil samples (0-20 cm) from China's third-largest city and analyzed their spectra (350-2500 nm). For each unknown validation sample, we selected its spatially nearby samples to construct the Cu estimation model. The results showed that compared to the traditional method (Rp2 = 0.75, RMSEP = 8.56, RPD = 1.73), incorporating nearby samples greatly improved the model (Rp2 = 0.93, RMSEP = 4.02, RPD = 3.89). As the number of nearby samples increased, the performance of the Cu estimation model followed an inverted U-shaped curve-initially increasing and then declining. The optimal number of nearby samples is 125 (62.5% of the total), and the mean distance between validation and calibration samples is 17 km. Therefore, we conclude that using nearby samples significantly enhances the Cu estimation model. The optimal number of nearby samples should strike a balance, covering a moderate area without there being too few or too many.

A Click Chemistry Strategy Toward Spin-Polarized Transition-Metal Single Site Catalysts for Dynamic Probing of Sulfur Redox Electrocatalysis.

Catalytic conversion of lithium polysulfides (LiPSs) is a crucial approach to enhance the redox kinetics and suppress the shuttle effect in lithium-sulfur (Li-S) batteries. However, the roles of a typical heterogenous catalyst cannot be easily identified due to its structural complexity. Compared with the distinct sites of single atom catalysts (SACs), each active site of single site catalysts (SSCs) is identical and uniform in their spatial energy, binding mode, and coordination sphere, etc. Benefiting from the well-defined structure, iron phthalocyanine (FePc) is covalently clicked onto CuO nanosheet to prepare low spin-state Fe SSCs as the model catalyst for Li-S electrochemistry. The periodic polarizability evolution of Fe-N bonding is probed during sulfur redox reaction by in situ Raman spectra. Theoretical analysis shows the decreased d-band center gap of Fe (Δd) and delocalization of dxz/dyz after the axial click confinement. Consequently, Li-S batteries with Fe SSCs exhibit a capacity decay rate of 0.029% per cycle at 2 C. The universality of this methodological approach is demonstrated by a series of M SSCs (M = Mn, Co, and Ni) with similar variation of electronic configuration. This work provides guidance for the design of efficient electrocatalysis in Li-S batteries.

Nematicidal effects of silencing arginine kinase in the pine wood nematode, Bursaphelenchus xylophilus, determined using a dsRNA-like siRNA assembly.

The pine wood nematode Bursaphelenchus xylophilus is a highly invasive species responsible for the widespread pine wilt disease. Double-stranded RNA (dsRNA) biopesticides represent a novel strategy for controlling plant-parasitic nematodes. The B. xylophilus arginine kinase (BxAK) features a conserved ATP-binding domain and exhibits nematode-specific divergence in the phylogenetic tree. Notably, whole-mount in situ hybridization signals are evident in the nematode head and middle sections, particularly in the juvenile stage before sex differentiation. In this study, we developed a novel dsRNA-like small interfering RNA (siRNA) assembly that specifically targets BxAK and presents highly nematicidal effects. The RNA interference (RNAi) efficiency achieved a 95.9 % reduction in second-stage juveniles. In bioassays, the median lethal concentrations of this siRNA assembly against B. xylophilus were 168.5 ng/µl for juveniles and 603.8 ng/µl for adults within 48 h. Moreover, transcriptomic results revealed significantly downregulated expression levels of genes related to metabolism and development, suggesting that the mode of action of BxAK silencing is related to disruptions in energy homeostasis and juvenile development. In conclusion, BxAK is a molecular target for controlling B. xylophilus, and our siRNA assembly significantly enhances RNAi efficiency and lowers the lethal concentration required, making it a promising candidate for future biocontrol applications.

[Research progress of electrospinning polyurethane fiber in the field of biomedical tissue engineering].

Polyurethane materials have good biocompatibility, blood compatibility, mechanical properties, fatigue resistance and processability, and have always been highly valued as medical materials. Polyurethane fibers prepared by electrostatic spinning technology can better mimic the structure of natural extracellular matrices (ECMs), and seed cells can adhere and proliferate better to meet the requirements of tissue repair and reconstruction. The purpose of this review is to present the research progress of electrostatically spun polyurethane fibers in bone tissue engineering, skin tissue engineering, neural tissue engineering, vascular tissue engineering and cardiac tissue engineering, so that researchers can understand the practical applications of electrostatically spun polyurethane fibers in tissue engineering and regenerative medicine.

Ene-Reductase-Catalyzed Aromatization of Simple Cyclohexanones to Phenols.

Direct aromatization of cyclohexanones to synthesize substituted phenols represents a significant challenge in modern synthetic chemistry. Herein, we describe a novel ene-reductase (TsER) catalytic system that converts substituted cyclohexanones into the corresponding phenols. This process involves the successive dehydrogenation of two saturated carbon-carbon bonds within the six-membered ring of cyclohexanones and utilizes molecular oxygen to drive the reaction cycle. It demonstrates a versatile and efficient approach for the synthesis of substituted phenols, providing a valuable complement to existing chemical methodologies.

Phytochemical constituents, bioactivities, and applications of custard apple (Annona squamosa L.): A narrative review.

Annona squamosa L. (Annonaceae) is a versatile tree with an edible fruit showing abundant medicinal and industrial applications. The nutritional values of this plant are due to carbohydrates, proteins, amino acids, and vitamins. Ethnopharmacological uses referred to treatment of dysentery, headlice, cancer sores, purgative, and tonic effects. The main reported biological activities for A. squamosa L. were cytotoxic, antidiabetic, antimicrobial, antiparasitic, antioxidant, antimalarial, molluscidal, anthelmintic and insecticidal activities, and its chemical classes encompassed alkaloids, diterpenes, acetogenins, and cyclopeptides. The nutritional content of A. squamosa L. and their main chemical components, biological effects, and the different applications were discussed in this review. This comprehensive review strived to compile all the relevant data in the period between 1990 and 2023 covering databases PubMed, ScienceDirect, Web of Science, Googlescholar and Reaxys concerning A. squamosa L. different parts with their reported phytochemical constituents and biological activities to integrate a better understanding of the medicinal values.

Relationship between changes in the triglyceride glucose-body mass index and frail development trajectory and incidence in middle-aged and elderly individuals: a national cohort study.

BACKGROUND: Insulin resistance is linked to an increased risk of frailty, yet the comprehensive relationship between the triglyceride glucose-body mass index (TyG-BMI), which reflects weight, and frailty, remains unclear. This relationship is investigated in this study. METHODS: Data from 9135 participants in the China Health and Retirement Longitudinal Study (2011-2020) were analysed. Baseline TyG-BMI, changes in the TyG-BMI and cumulative TyG-BMI between baseline and 2015, along with the frailty index (FI) over nine years, were calculated. Participants were grouped into different categories based on TyG-BMI changes using K-means clustering. FI trajectories were assessed using a group-based trajectory model. Logistic and Cox regression models were used to analyse the associations between the TyG-BMI and FI trajectory and frail incidence. Nonlinear relationships were explored using restricted cubic splines, and a linear mixed-effects model was used to evaluate FI development speed. Weighted quantile regression was used to identify the primary contributing factors. RESULTS: Four classes of changes in the TyG-BMI and two FI trajectories were identified. Individuals in the third (OR = 1.25, 95% CI: 1.10-1.42) and fourth (OR = 1.83, 95% CI: 1.61-2.09) quartiles of baseline TyG-BMI, those with consistently second to highest (OR = 1.49, 95% CI: 1.32-1.70) and the highest (OR = 2.17, 95% CI: 1.84-2.56) TyG-BMI changes, and those in the third (OR = 1.20, 95% CI: 1.05-1.36) and fourth (OR = 1.94, 95% CI: 1.70-2.22) quartiles of the cumulative TyG-BMI had greater odds of experiencing a rapid FI trajectory. Higher frail risk was noted in those in the fourth quartile of baseline TyG-BMI (HR = 1.42, 95% CI: 1.28-1.58), with consistently second to highest (HR = 1.23, 95% CI: 1.12-1.34) and the highest TyG-BMI changes (HR = 1.58, 95% CI: 1.42-1.77), and those in the third (HR = 1.10, 95% CI: 1.00-1.21) and fourth quartile of cumulative TyG-BMI (HR = 1.46, 95% CI: 1.33-1.60). Participants with persistently second-lowest to the highest TyG-BMI changes (ß = 0.15, 0.38 and 0.76 respectively) and those experiencing the third to fourth cumulative TyG-BMI (ß = 0.25 and 0.56, respectively) demonstrated accelerated FI progression. A U-shaped association was observed between TyG-BMI levels and both rapid FI trajectory and higher frail risk, with BMI being the primary factor. CONCLUSION: A higher TyG-BMI is associated with the rapid development of FI trajectory and a greater frail risk. However, excessively low TyG-BMI levels also appear to contribute to frail development. Maintaining a healthy TyG-BMI, especially a healthy BMI, may help prevent or delay the frail onset.

Comprehensive pan-cancer analysis of ACSS3 as a biomarker for prognosis and immunotherapy response.

Background: ACSS3 (acyl-CoA synthetase short-chain family member 3) is found in numerous tissues and is linked to tumor cell type development and metastasis. Methods: We conducted a comprehensive pan-cancer analysis of ACSS3. The TCGA (Cancer Genome Atlas), CPTAC (Clinical Proteomic Tumor Analysis Consortium), and HPA databases were used to ascertain the connection between ACSS3 and various types of tumors. Genes in the TCGA database would be identified using cBioPortal queries, and their transcriptome expression would then be verified using GEO data. ACSS3 expression and cellular localization in various tumor tissues of most cancer types were analyzed using single-cell sequencing data from the TISCH database. According to HPA and CPTAC databases, we analyzed and evaluated protein expression levels. Predictive analysis based on precise survival data of ACSS3 expression levels for 26 cancer types predicted using the TCGA database. Furthermore, we investigated the relationship between ACSS3 and immune microenvironments in different tumor tissues using the TIMER and TISCH databases. CellMiner, GDSC, and CTRP data would clarify the relationship between ACSS3 and drug resistance and explore the chemicals that affect ACSS3 expression. The final part of our study explored and validated the role ACSS3 played in glioma proliferation, migration, and invasion. Results: ACSS3 is differentially expressed in various tumors and exhibits early diagnostic value. ACSS3 expression is associated with clinical features, and high ACSS expression anticipates a worse prognosis in multiple tumors and may impact drug sensitivity. The changes in the immunosuppressive microenvironment of gliomas are closely related to the upregulation of ACSS3. Conclusions: ACSS3 is a novel biomarker for forecasting different human cancer prognoses, as it can influence the biological process by modulating the immune microenvironment. ACSS3 is a critical prognostic factor for glioma and is related to its proliferation, migration, and invasion.

Near-field coupling between topological corner states.

In this Letter, we investigate the near-field coupling between topological corner states. As a proof of concept, we build a higher-order topological photonic structure with a square lattice, based on the 2D Su-Schrieffer-Heeger (SSH) model. It is demonstrated that the topological corner state can be hosted at a corner via engineering its two boundaries, whereupon the near-field coupling between two corner states is investigated by bringing them close together. Numerical and theoretical results show that the near-field coupling between two corner states results in hybridized local resonances and significant enhancement of density of states, which are similar to the plasmonic resonances and Mie resonances. Moreover, the extraordinary advantage of the coupled corner states is verified via enhancing third-harmonic generation. Our results may provide insight into studying topological photonics with multimodes as well as an effective approach for manipulation of light.

Calcium leakage involved in nematotoxic effects of the Conidiobolus obscurus CytCo protein on the pine wood nematode, Bursaphelenchus xylophilus.

BACKGROUND: The pine wood nematode Bursaphelenchus xylophilus, a severe invasive species, is responsible for causing widespread pine wilt disease. The CytCo protein, a pore-forming toxin derived from Conidiobolus obscurus, exhibits nematotoxicity towards B. xylophilus. RESULTS: Our present study reveals the expression variation of a range of gene products in B. xylophilus that respond to the effects of CytCo using the isobaric tags for relative and absolute quantification proteomics technology. Functional enrichment analysis indicates that many differentially expressed proteins are linked to calcium signaling system, proteasome, energy production and conversion, and the determination of adult lifespan. It suggests that the dysregulation of calcium homeostasis, energy metabolism, and apoptosis contribute to the CytCo nematotoxicity. Using the calcium ion (Ca2+)-indicator calcein, we detected changes in Ca2+ levels in B. xylophilus, with a significantly increase in fluorescence in the nematode's intestine and pseudocoelom following CytCo treatments. Meanwhile, the apoptosis and reactive oxygen species (ROS) assays showed an enhancement of fluorescence in B. xylophilus cells, with increased CytCo concentrations. CONCLUSION: The protein toxin CytCo triggers Ca2+ leakage, disrupts Ca2+ balance in B. xylophilus, and induces apoptosis and ROS outburst, thereby intensifying its nematotoxic effects. This finding facilitates our understanding of the modes of action of nematotoxic proteins, and contributes to the development of innovative nematode control strategies. © 2024 Society of Chemical Industry.

Chemo-, regio-, and stereoselective tetrafunctionalization of fluoroalkynes enables divergent synthesis of 5-7-membered azacycles.

Alkyne annulation has been widely used in organic synthesis for the construction of azacycles with unique structural and physicochemical properties. However, the analogous transformation of fluoroalkynes remains a challenge and has seen limited progress. Herein we report a 1,2,3,4-tetrafunctionalization of polyfluoroalkynes for the divergent construction of 5-7-membered (E)-1,2-difluorovinyl azacycles. The use of the fluorine atom as a detachable "activator" not only obviates the use of any transition metal catalysts and oxidizing reagents, but also ensures the [3-5 + 2]-annulation and defluorinative functionalization of fluoroalkynes with high chemo-, regio-, and stereoselectivities. This method exhibits a broad substrate scope, good functional group tolerance, and excellent scalability, providing a modular platform for accessing fluorinated skeletons of medicinal and biological interest. The late-stage modification of complex molecules, the multi-component 1,2-diamination of fluoroalkyne, and the synthesis of valuable organofluorides from the obtained products further highlight the real-world utility of this fluoroalkyne annulation technology.

Leucosceptrane sesterterpenoids from Tibetan Leucosceptrum canum and their immunosuppressive activity.

Phytochemical investigation on the leaves of Tibetan Leucosceptrum canum, a Chinese medicinal herb, led to the isolation of seven new leucosceptrane sesterterpenoids (1-7) and five known analogs (8-12). Comprehensive spectroscopic analysis (including 1D and 2D NMR, and HRMS), quantum chemistry computations, and single crystal X-ray crystallographic analysis were applied to elucidate their structures. Compounds 1-3 and 6 were the first examples of the leucosceptrane sesterterpenoids with rare C-2 oxidation. Compound 2 exhibited immunosuppressive activities via suppressing the secretion of cytokines IL-6 and TNF-α in LPS-induced macrophages RAW264.7 with IC50 values of 13.39 and 19.34 µM, respectively.

Spatial patterning and species coexistence: A case study using concentric circular vegetation patches in saline land.

Spatial patterns in plant community structures within stressed ecosystems have drawn much attention in the field of ecology. However, the mechanisms underlying spatial formation and its impact on species coexistence and diversity remain controversial. In this study, we investigated concentric circular vegetation patches in coastal saline land, and analysed the spatial patterning of plant communities and associated soil physicochemical properties. Thereafter, we tested how the soil conditioned by plant communities from different locations within the vegetation patches influence the species growth and inter-specific competition. Our results show soil salinity enlarges in a centrifugal manner in horizontal direction in all patches. Soil salinity decreased and species diversity increased along with the increase of patch size. In addition, we found significant shifts in both the composition of plant communities and in soil physicochemical properties from outer to center. The results indicate that the pioneer species Suaeda salsa facilitated the subsequent species. However Suaeda salsa was inhibited and became inferior competitor in the soil conditioned by the subsequent species. We infer that the less-visible spatial patterns of soil physicochemical properties at small scales create ecological niches for specialized species, allowing them to coexist but not mix. We suggest that a trade-off between tolerance to salt stress and competitive ability under ameliorated conditions may underlie mechanisms of pattern formation in small scale. Our findings lend support to the idea that soil stress constraints community assembly and triggers spatial patterns, which, in turn, buffer the stress on plant communities and enhance species diversity.