Search

Human activities are the main factors threatening ecosystems, and ecological management should place a strong emphasis on guiding their positive development. More targeted and differentiated ecological preservation strategies can be proposed with research on the regional variability of the interaction between ecosystems and human activities. Utilizing the Vigor-Organization-Resilience-Services (VORS) model and the land surface human activity intensity model, the ecosystem health index (EHI) and human activity intensity (HAI) of the Poyang Lake Ecological Economic Zone (PLEEZ) were evaluated, respectively. Furthermore, their spatial association was investigated using spatial autocorrelation analysis, and the effect of HAI on EHI was analyzed using Geographic Detector and Geographic Weighted Regress. The results revealed that in the PLEEZ, (1) The zones of intensified human activity were highly consistent with the expansion of built-up land, and the EHI here has always been the lowest; (2) The HAI and EHI showed a significant and increasing spatial negative correlation, manifested as high HAI with low EHI clustering in the central plains and the adverse in the peripheral mountainous areas. (3) The HAI has the highest explanatory power on the spatial pattern of EHI, and its influence was greatest at the lower EHI. (4) Natural ecosystems with high EHI were highly sensitive to HAI, while areas with low EHI were less sensitive. The research can offer theoretical guidance for ecological construction in the future. The adverse effects of human activities in PLEEZ can be reduced through strict regulation of natural ecological sources, intensive utilization of human gathering areas, and promotion of green production and lifestyle.

Background: White matter hyperintensity (WMH) burden may lead to poor clinical outcomes after endovascular thrombectomy (EVT). But the relationship between WMH burden and cerebral edema (CED) is unclear. Purpose: To examine the association between WMH burden and CED and functional outcome in patients treated with EVT. Study Type: Retrospective. Subject: 344 patients with acute anterior circulation large‐vessel occlusion stroke who received EVT at two comprehensive stroke centers. Mean age was 62.6 ± 11.6 years and 100 patients (29.1%) were female. Field Strength/Sequence: 3T, including diffusion‐weighted imaging and fluid‐attenuated inversion recovery (FLAIR) images. Assessment: The severity of WMH was evaluated using the Fazekas scale on a FLAIR sequence before EVT. The severity of CED was assessed using CED score (three for malignant cerebral edema [MCE]) and net water uptake (NWU)/time on post‐EVT cranial CT. The impact of WMH burden on MCE, NWU/time, and 3‐month poor outcome (modified Rankin scale >2) after EVT were assessed. Statistical Tests: Pearson's chi‐squared test, Fisher exact test, 2‐tailed t test, Mann–Whitney U test, multivariable logistic regression, multivariate regression analysis, Sobel test. A P value <0.05 was considered statistically significant. Results: WMH burden was not significantly associated with MCE and parenchymal hemorrhage (PH) in the whole population (P = 0.072; P = 0.714). WMH burden was significantly associated with an increased risk of MCE (OR, 1.550; 95% CI, 1.128–2.129), higher NWU/time (Coefficient, 0.132; 95% CI, 0.012–0.240), and increased risk of 3‐month poor outcome (OR, 1.434; 95% CI, 1.110–1.853) in the subset of patients without PH. Moreover, the connection between WMH burden and poor outcome was partly mediated by CED in patients without PH (regression coefficient changed by 29.8%). Data Conclusion: WMH burden is associated with CED, especially MCE, and poor outcome in acute ischemic stroke patients treated with EVT. The association between WMH burden and poor outcome may partly be attributed to postoperative CED. Level of Evidence: 3. Technical Efficacy: Stage 5. [ABSTRACT FROM AUTHOR]

A simple and effective strategy for designing a ratiometric fluorescent nanosensor was described. A carbon dots (CDs) based dual-emission nanosensor for chromium speciation analysis was developed by coating CDs on the surface of dye-doped silica nanoparticles. The fluorescence of the resulting dual-emission silica nanoparticles was quenched in acetic acid through potassium bromate (KBr[O.sub.3]) oxidation. Cr(VI) was able to catalyze KBr[O.sub.3] oxidation, resulting in ratiometric fluorescence accelerated quenching response of the dual-emission silica nanoparticles. Several important parameters affecting the nanosensor performance, including acid type, concentrations of KBr[O.sub.3], and reaction temperature and time were examined. Under the optimized conditions, the detection limit of the nanosensor towards Cr(VI) reached 1.3 ng [mL.sup.-1] and pretty good linearity was obtained between 20 to 500 ng [mL.sup.-1]. More importantly, the sensor was found suitable for speciation analysis of both Cr(III) and Cr(VI) in different water samples with satisfactory results. Key words: ratiometric fluorescent probe, speciation analysis, Cr(VI), silica nanoparticles, water samples analysis. Nous presentons une strategie simple et efficace pour elaborer un nanocapteur fluorescent ratiometrique. Nous avons mis au point un nanocapteur a double emission a base de points de carbone pour l'analyse de speciation du chrome en recouvrant les points de carbone a la surface de nanoparticules de silice dopees par un pigment. Nous avons observe dans l'acide acetique une extinction de fluorescence de ces nanoparticules de silice a double emission par oxydation du bromate de potassium (KBr[O.sub.3]). Le Cr(VI) a catalyse l'oxydation du KBr[O.sub.3], ce qui s'est traduit par une extinction acceleree de la fluorescence des nanoparticules de silice a double emission. Nous avons evalue plusieurs parametres ayant une influence importante sur la performance du nanocapteur, dont le type d'acide, les concentrations de KBr[O.sub.3], ainsi que la temperature et le temps de reaction. En conditions optimisees, le nanocapteur a presente une limite de detection du Cr(VI) atteignant 1,3 ng [mL.sup.-1] et une linearite satisfaisante dans l'intervalle de 20 a 500 ng [mL.sup.-1]. Notons que le capteur a permis de realiser de maniere satisfaisante l'analyse de speciation, tant du Cr(III) que du Cr(VI), dans differents echantillons d'eau. [Traduit par la Redaction] Mots-cles : sonde fluorescente ratiometrique, analyse de speciation, Cr(VI), nanoparticules de silice, analyse d'echantillons d'eau., Introduction During the last decades, the release of effluents containing high amounts of chromium and other heavy metals increased as anthropogenic activities rose. Ore dressing, leather tanning, and metal plating [...]

A simple and effective strategy for designing a fluorescent probe for bromate was described in this work. Organosilane modified carbon dots were prepared by pyrolysis of citric acid in N-([beta]-aminoethyl)-[gamma]-aminopropyl methyldimethoxysilane solvent at 230 [degrees]C and further doped onto silica nanoparticles by a silylation reaction. The fluorescence of carbon dot doped silica nanoparticles was quenched by bromate in acidic medium. By utilizing this property, the nanoparticle could be used as a sensor to detect bromate. The parameters affecting the performance of the sensor probe such as types of acid medium, acid concentration, reaction temperature, and time were investigated and optimized. The detection limit of the sensor was found to be 1.1 ng [mL.sup.-1], with a linear range from 8 to 400 ng [mL.sup.-1] and relative standard deviation of 2.0% (150 ng [mL.sup.-1], n = 9). The method was successfully applied to the determination of bromate in drinking water samples, and the recoveries were in the range of 96.3%-103.7%. Key words: carbon dots, bromate, silica nanoparticles, drinking water sample. Dans le cadre des presents travaux, nous avons decrit une strategie simple et efficace pour la conception d'une sonde fluorescente capable de detecter le bromate. Nous avons prepare par pyrolyse de l'acide citrique dans le N-([beta]-aminoethyl)-[gamma]-aminopropylmethyldimethoxysilane comme solvant a 230 [degrees]C des points quantiques de carbone modifies par des organosilanes, que nous avons utilises pour doper des nanoparticules de silice par reaction de silylation. L'extinction de la fluorescence des nanoparticules de silice dopees par les points quantiques de carbone s'est produite en presence du bromate en milieu acide. En exploitant cette propriete, il est possible d'utiliser cette nanoparticule comme capteur pour detecter le bromate. Nous avons etudie et optimise les parametres qui influent sur la performance de la sonde de detection, tels que le milieu acide, la concentration de l'acide ainsi que la temperature et le temps de reaction. Le capteur a revele une limite de detection de 1,1 ng [mL.sup.-1] dans un intervalle lineaire de8a 400 ng [mL.sup.-1], avec un ecart-type de 2,0 % (150 ng [mL.sup.-1], n = 9). En appliquant cette methode, nous avons reussi a doser le bromate dans des echantillons d'eau potable avec des taux de recuperation variant de 96,3 a 103,7 %. [Traduit par la Redaction] Mots-cles : points quantiques de carbone, bromate, nanoparticules de silice, echantillon d'eau potable., Introduction Ozone is a strong oxidizing agent that can oxidize organic and inorganic substances in water (1,2) and is commonly used as a disinfectant. Ozone reacts with bromide to produce [...]