Promoted Reaction Reversibility by Dual-Effect 15-Crown-5 Ether Additive for High-Performance Li-O2 Batteries.

The practical application of lithium-oxygen batteries (LOBs) with ultrahigh theoretical energy density faces the problems of poor kinetics and deficient reversibility. The electrolyte is of vital significance to the electrochemical stability and reaction pathway of LOBs due to the formation of soluble products. Here, a 15-crown-5 ether (15C5) is employed to regulate the solvation structure of Li+ and manipulate the reaction mechanism through regulating the binding ability toward Li+. The promoted dissociation of LiNO3 by 15C5 increases the catalytical active anions in the electrolyte and stabilizes the Li-containing reduced oxygen species to promote the solution pathway of discharge product growth. Besides, 15C5 also facilitates the kinetics of the electrochemical decomposition of Li2O2 and prolongs the cycle life to 178 cycles. This work inspires a novel approach to improve the battery performance through electrolyte component design.

Biogenic volatile organic compounds in forest therapy base: A source of air pollutants or a healthcare function?

Air pollution poses a significant threat to public health, while biogenic volatile organic compounds (BVOCs) play a crucial role in both aspects. However, the unclear relationship between BVOCs and air pollutants in the under-canopy space limits the accuracy of air pollution control and the exploitation of forest healthcare functions. To clarify the variation of BVOCs in forest therapy bases, and their impacts on ozone (O3) and fine particulate matter (PM2.5) at nose height, total VOCs (TVOCs) in the forest were collected during typical sunny days, while air pollutants and meteorological factors were observed simultaneously. The results showed that the branch-level emissions of P. tabuliformis were dominated by healthcare-effective monoterpenoids, with only α-pinene having relative air concentrations of over 5 % in forest air samples. The correlation between concentrations of under-canopy TVOCs and emission rates of BVOCs from P. tabuliformis was weak (p > 0.09) in all seasons. However, the correlation between concentrations of TVOCs and the concentrations of O3 and PM2.5 showed clear seasonal differences. In spring, TVOCs only showed a significant negative correlation with PM2.5 in the forest (p < 0.01). In summer and autumn, TVOCs were significantly negatively correlated with both O3 (p < 0.001) and PM2.5 (p < 0.01). Specifically, the negative linear relationships were more pronounced for O3 and oxygenated VOCs in autumn (R2 = 0.40, p < 0.001) than for other relationships. The relationship between air pollutant concentrations inside and outside the forest also showed significant seasonal differences, generally characterized by a weaker correlation between them during seasons of strong emissions. Therefore, BVOCs in coniferous forests are health functions as they can provide healthcare effects and mitigate the concentration of air pollutants in the forest, and the establishment of forest therapy bases in rural areas with low NOx can be a sensible approach to promote good health, well-being, and sustainable development.

The Fitting of the OJ Phase of Chlorophyll Fluorescence Induction Based on an Analytical Solution and Its Application in Urban Heat Island Research.

Chlorophyll (Chl) fluorescence induction (FI) upon a dark-light transition has been widely analyzed to derive information on initial events of energy conversion and electron transfer in photosystem II (PSII). However, currently, there is no analytical solution to the differential equation of QA reduction kinetics, raising a doubt about the fitting of FI by numerical iteration solution. We derived an analytical solution to fit the OJ phase of FI, thereby yielding estimates of three parameters: the functional absorption cross-section of PSII (σPSII), a probability parameter that describes the connectivity among PSII complexes (p), and the rate coefficient for QA- oxidation (kox). We found that σPSII, p, and kox exhibited dynamic changes during the transition from O to J. We postulated that in high excitation light, some other energy dissipation pathways may vastly outcompete against excitation energy transfer from a closed PSII trap to an open PSII, thereby giving the impression that connectivity seemingly does not exist. We also conducted a case study on the urban heat island effect on the heat stability of PSII using our method and showed that higher-temperature-acclimated leaves had a greater σPSII, lower kox, and a tendency of lower p towards more shade-type characteristics.

Ecological transformation is the key to improve ecosystem health for resource-exhausted cities: A case study in China based on future development scenarios.

Numerous cities are currently grappling with the challenge of ecological transformation, especially those categorized as resource-exhausted cities. In these urban areas, land use change is a highly scrutinized issue, as different land use strategies can lead to varied outcomes, impacting the ecological environment in multiple dimensions. Assessing ecosystem health reflects the quality of the regional ecological environment and serves as a comprehensive indicator for evaluating the sustainability and stability of urban ecosystems. To this end, a multi-objective optimization model was constructed to predict land use changes under four future development scenarios (four ecological transformation modes), using Shizuishan City (China), a resource-exhausted city situated in an ecologically fragile area, as an example. The "vigor-organization-resilience" assessment framework was employed to evaluate the ecosystem health conditions in each scenario from three dimensions. The study results showed: (1) The ranking of the average ecological health levels in Shizuishan City for 2022 and different future development scenarios is as follows: Low-Carbon Economic Development Scenario (0.302) > Ecological-Economic Coordinated Development Scenario (0.291) > Baseline Scenario (0.290) > Economic Development Scenario (0.281) > 2022 (0.248). (2) Compared to 2022, the ecosystem health levels under the four ecological transformation modes had all improved, with improvement areas accounting for over 60 %, highlighting the urgent necessity of ecological transformation in Shizuishan City. Among them, the Low-Carbon Economic Development Scenario exhibited the largest improvement area, reaching 75.81 %. (3) Ecological system vitality was identified as the dominant dimension influencing the ecological health in this region. This study emphasized multi-objective development needs and provided an integrated ecosystem health assessment method for assessing the comprehensive ecological effects of future ecological transformation modes in resource-exhausted cities.

Exosomes-mediated drug delivery for the treatment of myocardial injury.

Cardiovascular disease has become a major cause of death worldwide. Myocardial injury (MI) caused by myocardial infarction, myocarditis, and drug overdose can lead to impaired cardiac function, culminating in serious consequences such as angina pectoris, arrhythmias, and heart failure. Exosomes exhibit high biocompatibility and target specificity, rendering them an important non-cellular therapy for improving MI. Exosomes are diminutive vesicles that encapsulate nucleic acids and proteins. Exosomes derived from cardiac stem cells themselves have therapeutic effects, and they can also serve as carriers to deliver therapeutic drugs to recipient cells, thereby exerting a therapeutic effect. The molecules within exosomes are encapsulated in a lipid bilayer, allowing them to stably exist in body fluids without being affected by nucleases. Therefore, the utilization of exosomes as drug delivery systems (DDS) for disease treatment has been extensively investigated and is currently undergoing clinical trials. This review summarizes the therapeutic effects of exosomes on MI and provides an overview of current research progress on their use as DDS in MI.

Effectiveness of Medication Reconciliation in a Chinese Hospital: A Pilot Randomized Controlled Trial.

Background: Implementing medication reconciliation (MR) was complex and challenging because of the variability in the guidance provided for conducting. The processes of MR adopted in China were different from that recommended by the World Health Organization. A pilot study to inform the design of a future randomized controlled trial to determine the effectiveness of these two workflows was undertaken. Methods: Patients taking at least one home/regular medication for hypertension, diabetes, or coronary heart disease were recruited at admission, and then were randomized using a computer-generated random number in a closed envelope. In the study group, the pharmacist reviewed electronic medical record systems before communication with patients. In the control group, pharmacists communicated with patients at patient's admission. The time investment of pharmacists for MR process, the number of unintended medication discrepancies, and physician acceptance were tested as outcome measures. Results: One hundred and forty adult patients were randomized, of which 66 patients in the intervention received MR within 24 hours, while 58 patients in control received MR at some point during admission. The most common condition in the study group was hypertension (coronary heart disease in the control group). The workflow of the study group can save an average 7 minutes per patient compared with the WHO recommended process [17.5 minutes (IQR 14.00, 28.25) vs 24.5 minutes (IQR17.75, 35.25), p = 0.004]. The number of unintended discrepancies was 42 in the study group and 34 in the control group (p = 0.33). Physicians' acceptance in the study and control groups were 87.5% and 92.3%, respectively (p = 0.87). Conclusion: The results suggest that changes in outcome measures were in the appropriate direction and that the time limit for implementing MR can be set within 48 hours. A future multi-centre RCT study to determine the effectiveness of MR is feasible and warranted.

Exposed anthocyanic leaves of Prunus cerasifera are special shade leaves with high resistance to blue light but low resistance to red light against photoinhibition of photosynthesis.

BACKGROUND AND AIMS: The photoprotective role of foliar anthocyanins has long been ambiguous: exacerbating, being indifferent to or ameliorating the photoinhibition of photosynthesis. The photoinhibitory light spectrum and failure to separate photo-resistance from repair, as well as the different methods used to quantify the photo-susceptibility of the photosystems, could lead to such a discrepancy. METHODS: We selected two congeneric deciduous shrubs, Prunus cerasifera with anthocyanic leaves and Prunus triloba with green leaves, grown under identical growth conditions in an open field. The photo-susceptibilities of photosystem II (PSII) and photosystem I (PSI) to red light and blue light, in the presence of lincomycin (to block the repair), of exposed leaves were quantified by a non-intrusive P700+ signal from PSI. Leaf absorption, pigments, gas exchange and Chl a fluorescence were also measured. KEY RESULTS: The content of anthocyanins in red leaves (P. cerasifera) was >13 times greater than that in green leaves (P. triloba). With no difference in maximum quantum efficiency of PSII photochemistry (Fv/Fm) and apparent CO2 quantum yield (AQY) in red light, anthocyanic leaves (P. cerasifera) showed some shade-acclimated suites, including lower Chl a/b ratio, lower photosynthesis rate, lower stomatal conductance and lower PSII/PSI ratio (on an arbitrary scale), compared with green leaves (P. triloba). In the absence of repair of PSII, anthocyanic leaves (P. cerasifera) showed a rate coefficient of PSII photoinactivation (ki) that was 1.8 times higher than that of green leaves (P. triloba) under red light, but significantly lower (-18 %) under blue light. PSI of both types of leaves was not photoinactivated under blue or red light. CONCLUSIONS: In the absence of repair, anthocyanic leaves exhibited an exacerbation of PSII photoinactivation under red light and a mitigation under blue light, which can partially reconcile the existing controversy in terms of the photoprotection by anthocyanins. Overall, the results demonstrate that appropriate methodology applied to test the photoprotection hypothesis of anthocyanins is critical.

The unrelenting global expansion of the urban heat island over the last century.

The past century has seen dramatic increases in global temperatures and mounting urbanization. As a result of these events, the urban heat island (UHI) effect has received growing attention in scientific research worldwide. A global search was initially conducted using a scientific literature database to collect all available relevant publications to understand how the UHI has been expanding worldwide and affecting more cities across different latitudes and altitudes. Subsequently, a semantic analysis was performed to extract city names. The literature search and analysis combined resulted in 6078 publications in which UHI was investigated in 1726 cities worldwide in the 1901 to 2022 time period. The cities were grouped into 'first appearance' and 'recurrent appearance'. Results show that UHI was studied in only 134 cities during the 90-year period from 1901 to 1992, with a remarkable growth over time in the number of cities where interest in UHI increased. Interestingly, the number of first appearances was always notably higher than the number of recurrent appearances. The Shannon evenness index was employed to identify the spatial locations (hotspots) across the globe where UHI-related research has been concentrated in multiple cities over the last 120 years. Finally, Europe was selected as a testbed for conducting an analysis to shed light on how economic, demographic, and environmental factors can impact UHI. Our study is unique for having demonstrated not only the rapid growth of cities affected by UHI globally but also the increasing and unrelenting expansion of UHI occurrences across different latitudes and altitudes over time. These novel findings will undoubtedly be of interest to scientists investigating the UHI phenomenon and its trends. Stakeholders will acquire a broader perspective and deeper understanding of UHI in order to engage in more effective urban planning to offset and mitigate the phenomenon's adverse effects in the context of increasing climate change and urbanization.

Urban park use and self-reported physical, mental, and social health during the COVID-19 pandemic: An on-site survey in Beijing, China.

The COVID-19 pandemic created unprecedented challenges for people's health. Studies have demonstrated the positive impact of urban green spaces, particularly urban parks, on physical and mental health. However, few studies have evaluated social health, which is a component of human health, and more understanding of the relationship between urban parks and human health during the COVID-19 pandemic is required. This study examined the effects of urban parks on people's health using a canonical correlation model. Physical, mental, and social health were the dependent health variables, and five factors related to urban parks were the independent variables. This study investigated 22 urban parks inside the Forth Ring Road in Beijing, China using a questionnaire survey. The results demonstrated a positive association between urban parks and human health during the pandemic. Distance to the parks, park area, and park size were positively correlated with physical, mental, and social health. Furthermore, frequency and duration of visits to urban parks were positively associated with mental health and contact with neighbors. The health effects of urban park use varied with park types and locations' urbanization background. These findings can provide insights for health-oriented urban park planning and construction.

The efficacy of cell-assisted versus conventional lipotransfer: A systematic review and meta-analysis.

Autologous lipotransfer is an essential component of soft tissue reconstruction. However, it is not widely applied or accepted by surgeons due to its unstable survival rate and uncertain efficacy. The cell-assisted fat transfer (CAL) is a promising technique that increases the fat survival rate. However, it is controversial based on various clinical studies. Here, we assessed the fat survival and complication rates of CAL, compared to the conventional autologous lipotransfer. To conduct our research, two reviewers independently screened related articles published in Medicine (via PubMed), EMBASE, Cochrane Library, and Web of Science. The combined effect estimates for efficacy evaluation was performed by the Review Manager software (RevMan 5.4.1). In total, 14 articles were included in our analysis (n = 722). Based on our analysis, the survival rate of the fat graft in CAL was significantly higher than the conventional fat grafting group (non-CAL group) (SMD = 2.81, 95%CI [1.54, 4.08], P < 0.01). In the subgroup, the fat retention of CAL in the facial filling was higher than the conventional one (SMD = 3.01, 95%CI [1.68, 4.33], P < 0.01). After breast augmentation, however, the difference between the experimental and control group was not statistically significant (SMD = 1.80, 95%CI [-0.31, 3.91], P = 0.09). Moreover, the CAL group exhibited comparable complications as the non-CAL group. Based on our analysis, the CAL group was significantly better than the conventional lipotransfer in terms of fat survival, particularly, during facial filling. However, it failed to reduce the complication rate, compared to the non-CAL group.

The Protective Role of Non-Photochemical Quenching in PSII Photo-Susceptibility: A Case Study in the Field.

Non-photochemical quenching (NPQ) has been regarded as a safety valve to dissipate excess absorbed light energy not used for photochemistry. However, there exists no general consensus on the photoprotective role of NPQ. In the present study, we quantified the Photosystem II (PSII) photo-susceptibilities (mpi) in the presence of lincomycin, under red light given to five shade-acclimated tree species grown in the field. Photosynthetic energy partitioning theory was applied to investigate the relationships between mpi and each of the regulatory light-induced NPQ [Y(NPQ)], the quantum yield of the constitutive nonregulatory NPQ [Y(NO)] and the PSII photochemical yield in the light-adapted state [Y(PSII)] under different red irradiances. It was found that in the low to moderate irradiance range (50-800 µmol m-2 s-1) when the fraction of open reaction centers (qP) exceeded 0.4, mpi exhibited no association with Y(NPQ), Y(NO) and Y(PSII) across species. However, when qP < 0.4 (1,500 µmol m-2 s-1), there existed positive relationships between mpi and Y(NPQ) or Y(NO) but a negative relationship between mpi and Y(PSII). It is postulated that both Y(NPQ) and Y(NO) contain protective and damage components and that using only Y(NPQ) or Y(NO) metrics to identify the photo-susceptibility of a species is a risk. It seems that qP regulates the balance of the two components for each of Y(NPQ) and Y(NO). Under strong irradiance, when both protective Y(NPQ) and Y(NO) are saturated/depressed, the forward electron flow [i.e. Y(PSII)] acts as the last defense to resist photoinhibition.

Long-Cycling All-Solid-State Batteries Achieved by 2D Interface between Prelithiated Aluminum Foil Anode and Sulfide Electrolyte.

All-solid-state batteries (ASSBs) with alloy anodes are expected to achieve high energy density and safety. However, the stability of alloy anodes is largely impeded by their large volume changes during cycling and poor interfacial stability against solid-state electrolytes. Here, a mechanically prelithiation aluminum foil (MP-Al-H) is used as an anode to construct high-performance ASSBs with sulfide electrolyte. The dense Li-Al layer of the MP-Al-H foil acts as a prelithiated anode and forms a 2D interface with sulfide electrolyte, while the unlithiated Al layer acts as a tightly bound current collector and ensures the structural integrity of the electrode. Remarkably, the MP-Al-H anode exhibits superior lithium conduction kinetics and stable interfacial compatibility with Li6 PS5 Cl (LPSCl) and Li10 GeP2 S12 electrolytes. Consequently, the symmetrical cells using LPSCl electrolyte can work at a high current density of 7.5 mA cm-2 and endure for over 1500 h at 1 mA cm-2 . Notably, ≈100% capacity is retained for the MP-Al-H||LPSCl||LiCoO2 full cell with high area loadings of 18 mg cm-2 after 300 cycles. This work offers a pathway to improve the interfacial and performance issues for the application of ASSBs.

Thinning can increase shrub diversity and decrease herb diversity by regulating light and soil environments.

Tree thinning affects the light environment, which in turn affects the growth and survival of understory vegetation, thus improving species diversity and nutrient cycling, as well as the ecological habitat factors. However, the response of understory vegetation to the thinning intensity and short-time effects in the temperate broadleaf-conifer mixed forest is not completely clear. In this study, four permanent plots with a total area of 4 hm2 were established in a mixed broadleaf-conifer forest in northeast China, with thinning intensities of 20% (light thinning, LT), 35% (medium thinning, MT), 55% (heavy thinning, HT) and the unthinned plot (CK), respectively, in accordance with the basal area. The responses of species diversity to changes in understory vegetation were conducted by a structural equation model (SEM). The results showed that compared with CK, thinning significantly increased the photosynthetically active radiation (PAR) and the light quality (R/FR) (p < 0.05), while decreased the contents of soil total nitrogen (TN), total phosphorous (TP), organic matter (OM), nitrate nitrogen (NN), ammonia nitrogen (AN) and pH. The degree of fragmentation of light factors among the treatment plots gradually decreased as thinning intensity increased. Among all the thinning treatments, PAR and R/FR were found to be the optimal light condition when the forest thinning intensity was 55%. The light condition was found to have a significant negative correlation with soil TN, TP, OM, and AN. While the soil nutrients were positively correlated with herbaceous layer diversity but negatively correlated with shrub layer diversity. The soil nutrients were lost after thinning in a short time and herb diversity decreased, but shrub diversity increased significantly compared with unthinned plots. For the understory vegetation, the species diversity of shrub and herb layer were showed to be more sensitive to soil nutrients than light environment.

Theoretical and Experimental Understanding of Metal Single-Atom Electrocatalysts for Accelerating the Electrochemical Reaction of Lithium-Sulfur Batteries.

Metal single-atom materials have attracted tremendous attention in the research field of lithium-sulfur (Li-S) batteries because they can effectively improve the reaction kinetics of sulfur cathodes. However, it is still difficult to determine the best metal single-atom catalyst for Li-S batteries, due to the lack of a unified measurement and evaluation method. Herein, a series of metal single-atom- and nitrogen-doped graphene materials (M-NG, M = Fe, Co, Ni, Ir, Ru) have been prepared as the catalysts for promoting the reaction kinetics of the sulfur reduction reaction process. Using rotating disk electrode measurements and density functional theory-based theoretical calculations, Ni-NG was screened out to be the best catalyst. It is found that Ni-NG materials can provide a kinetically favorable pathway for the reversible conversion of polysulfide conversion, thus increasing the utilization of sulfur. By coating the Ni-NG materials on the separator as a multifunctional interlayer, a commercially available sulfur cathode presents a stable specific capacity of 701.8 mAh g-1 at a current rate of 0.5C over 400 cycles. Even with a high sulfur loading of 3.8 mg cm-2, a high areal capacity of 4.58 mAh cm-2 can be achieved. This work will provide a fundamental understanding of efficient single-atom catalyst materials for Li-S batteries.

EQCM Investigation of a Dual-Doped Polymer Electrode for Li-Ion Batteries with Improved Reversible Capacity.

Polymer-based materials with the incorporation of redox-active dopants serve as promising electrodes for Li-ion batteries but their use is restricted by the limited doping level and inevitable dissolution behavior of the dopants. Here, we proposed a conjugated polymer-based electrode with an assistant dopant to realize the reversible capacity contribution of a redox-active dopant. By employing phosphate anion (PO) as the assistant dopant to stable the polymer matrix, the reversible capacity was improved by introducing indigo carmine (IC) into the polymer electrode. Based on the real-time monitoring of the electrochemical quartz crystal microbalance toward the mass change, the charge storage behavior of the redox-active dopant IC was observed and the stabilizing effect of the assistant dopant PO was revealed. The modified electrode delivered an increased capacity of 191 mA h g-1, and the reversible capacity remained 56% higher than that of the PO-undoped electrode after 200 cycles. The dual-doping strategy with the assistant dopant and the redox-active dopant is used to develop advanced polymer-based electrodes for high-capacity and long-cycling batteries.

SLCO4A1-AS1 triggers the malignant behaviours of melanoma cells via sponging miR-1306-5p to enhance PCGF2.

Melanoma belongs to cutaneous malignancy. Long non-coding RNAs (lncRNAs) have been suggested as crucial effectors in modulating progression of different malignancies, including melanoma. However, novel lncRNA solute carrier organic anion transporter family member 4A1 antisense RNA 1 (SLCO4A1-AS1) was not reported in melanoma. Herein, SLCO4A1-AS1 was detected to be up-regulated in melanoma cell lines compared with human normal melanocytes (HEM-a). Additionally, proliferation, migration and invasion of melanoma cells were weakened but apoptosis was facilitated due to SLCO4A1-AS1 down-regulation. Subsequently, miR-1306-5p was revealed to be sequestered by SLCO4A1-AS1 and down-regulated in melanoma cells. Functional assays further sustained that overexpressed miR-1306-5p had inhibitory influence on proliferation, migration and invasion and promoting influence on apoptosis of melanoma cells. Polycomb group ring finger 2 (PCGF2) was predicted as the downstream of miR-1306-5p, displaying aberrantly high expression in melanoma cell lines. Furthermore, PCGF2 expression was negatively modulated by miR-1306-5p and positively regulated by SLCO4A1-AS1. Finally, rescue assays demonstrated melanoma cell malignant behaviours suppressed by SLCO4A1-AS1 knockdown could be reversed by overexpressed PCGF2. Our study suggested that SLCO4A1-AS1 promoted the melanoma cell malignant behaviours via targeting miR-1306-5p/PCGF2, which might facilitate the discovery of novel biomarkers for melanoma treatment.

LINC01116 Facilitates Melanoma 1 Progression Via Sequestering miR-3612 and Up-regulating GDF11 and SDC3.

BACKGROUND: Melanoma is the deadliest cutaneous malignant tumor with high risks. Though increasing evidence has widely referred to the involvement of long non-coding RNAs (lncRNAs) in the mechanism of tumor development, including melanoma, the functional roles of most lncRNAs in melanoma remain to be explored. In this study, we focus on disclosing the role of long intergenic non-protein coding RNA 1116 (LINC01116) in melanoma. METHODS: Firstly, we detected LINC01116 expression through RT-qPCR. Functional analysis and animal experiments were carried out to assess the role of LINC01116 in vivo and in vitro. Western blot analysis was employed for detection of important markers regarding epithelial mesenchymal transition (EMT). In addition, RNA pulls down, RIP and luciferase reporter assays were performed to probe into the regulatory mechanism of LINC01116. RESULTS: LINC01116 was significantly up regulated in melanoma cells. LINC01116 deficiency abrogated cell proliferation, migration, invasion and EMT in melanoma. Moreover, LINC01116 enhanced growth differentiation factor 11 (GDF11) and syndecan 3 (SDC3) expression through sponging microRNA-3612 (miR-3612). The oncogenic role of the LINC01116/miR-3612/GDF11/SDC3 axis in melanoma was finally demonstrated. CONCLUSION: Conclusively, LINC01116 sequestered miR-3612 and targeted GDF11 and SDC3 to contribute to the progression of melanoma.

Leaf reflectance and functional traits as environmental indicators of urban dust deposition.

BACKGROUND: How to quickly predict and evaluate urban dust deposition is the key to the control of urban atmospheric environment. Here, we focus on changes of plant reflectance and plant functional traits due to dust deposition, and develop a prediction model of dust deposition based on these traits. RESULTS: The results showed that (1) The average dust deposition per unit area of Ligustrum quihoui leaves was significantly different among urban environments (street (18.1001 g/m2), community (14.5597 g/m2) and park (9.7661 g/m2)). Among different urban environments, leaf reflectance curves tends to be consistent, but there were significant differences in leaf reflectance values (park (0.052-0.585) > community (0.028-0.477) > street (0.025-0.203)). (2) There were five major reflection peaks and five major absorption valleys. (3) The spectral reflectances before and after dust removal were significantly different (clean leaves > dust-stagnant leaves). 695 ~ 1400 nm was the sensitive range of spectral response. (4) Dust deposition has significant influence on slope and position of red edge. Red edge slope was park > community > street. After dust deposition, the red edge position has obviously "blue shift". The moving distance of the red edge position increases with the increase of dust deposition. The forecast model of dust deposition amount established by simple ratio index (y = 2.517x + 0.381, R2 = 0.787, RMSE (root-mean-square error) = 0.187. In the model, y refers to dust retention, x refers to simple ratio index.) has an average accuracy of 99.98%. (5) With the increase of dust deposition, the specific leaf area and chlorophyll content index decreased gradually. The leaf dry matter content, leaf tissue density and leaf thickness increased gradually. CONCLUSION: In the dust-polluted environment, L. quihoui generally presents a combination of characters with lower specific leaf area, chlorophyll content index, and higher leaf dry matter content, leaf tissue density and leaf thickness. Leaf reflectance spectroscopy and functional traits have been proved to be effective in evaluating the changes of urban dust deposition.

Leaf functional traits differentiation in relation to covering materials of urban tree pits.

BACKGROUND: Understanding the ecological strategies of urban trees to the urban environment is crucial to the selection and management of urban trees. However, it is still unclear whether urban tree pit cover will affect plant functional traits. Here, we study the response of urban trees to different tree pit covers, analyzed the effects of different cover types on soil properties and their trade-off strategies based on leaf functional traits. RESULTS: We found that there were obvious differences in the physical properties of the soil in different tree pit covers. Under the different tree pit cover types, soil bulk density and soil porosity reached the maximum under cement cover and turf cover, respectively. We found that tree pit cover significantly affected the leaf properties of urban trees. Leaf thickness, chlorophyll content index and stomatal density were mainly affected by soil bulk density and non-capillary porosity in a positive direction, and were affected by soil total porosity and capillary porosity in a negative direction. Leaf dry matter content and stomata area were mainly negatively affected by soil bulk density and non-capillary porosity, and positively affected by soil total porosity and capillary porosity. Covering materials of tree pits promoted the functional adjustment of plants and form the best combination of functions. CONCLUSION: Under the influence of tree pit cover, plant have low specific leaf area, stomata density, high leaf thickness, chlorophyll content index, leaf dry matter content, leaf tissue density and stomata area, which belong to "quick investment-return" type in the leaf economics spectrum.

Intraspecific differences in plant functional traits are related to urban atmospheric particulate matter.

BACKGROUND: Functional trait-based ecological research has been instrumental in advancing our understanding of environmental changes. It is still, however, unclear how the functional traits of urban plants respond to atmospheric particulate matter, and which trade-off strategies are shown. In order to explore the variation of plant functional traits with the gradient of urban atmospheric particulate matter, we divided atmospheric particulate matter into three levels according to road distance, and measured the variation of six essential leaf functional traits and their trade-off strategies. RESULTS: Here, we show that the functional traits of plants can be used as predictors of plant response to urban atmospheric particulate matter. Within the study, leaf thickness, leaf dry matter content, leaf tissue density, stomatal density were positively correlated with atmospheric particulate matter. On the contrary, chlorophyll content index and specific leaf area were negatively correlated with atmospheric particulate matter. Plants can improve the efficiency of gas exchange by optimizing the spatial distribution of leaf stomata. Under the atmospheric particulate matter environment, urban plants show a trade-off relationship of economics spectrum traits at the intraspecific level. CONCLUSION: Under the influence of urban atmospheric particulate matter, urban plant shows a "slow investment-return" type in the leaf economics spectrum at the intraspecific level, with lower specific leaf area, lower chlorophyll content index, ticker leaves, higher leaf dry matter content, higher leaf tissue density and higher stomatal density. This finding provides a new perspective for understanding the resource trades-off strategy of plants adapting to atmospheric particulate matter.