Impact of built environment on urban surface temperature based on multi-source data at the community level in Beilin District, Xi'an, China.

With the global warming and rapid urbanization in China, the urban built environment has undergone rapid changes, and the land surface temperatures (LSTs) of urban communities have obvious spatial heterogeneity. To explore the key driving factors of community LSTs, the multi-source data and spatial statistical methods being jointly used to analyze the spatial characteristics and main influencing factors of LST at the community level in the Beilin District of Xi'an City, China. The results are as follows: (1) Compared with communities dominated by construction land, communities with large area of green space and water bodies have lower LST. (2) According to the Akaike's information criterion (AICc) and maximum of adjusted R2, and other parameters, the No.1236 model was selected as the optimal model to analyze the influencing factors of community LST by exploratory data analysis, including building density (BD), building height standard deviation (BHS), percentage of public administration and public services land (PASL), percentage of green space and square land (PGSL), population density (POPD), normalized difference impervious surface index (NDISI), and perimeter-area fractal dimension (PAFRAC). (3) For each increase of one unit in NDISI and BHS when other factors remain unchanged, the LST will increase by 0.569 °C and decrease by 0.478 °C, respectively. (4) From the spatial stability and distribution of Local-R2, the warming factors of community LST are mainly NDISI, PAFRAC, BD, and PASL, while the cooling factors are BHS and PGSL. The spatial heterogeneity of community LST is not only related to the change of underlying surface properties but is also affected by intra-urban architectural morphology. Therefore, reasonable planning of urban built environment is of great significance for mitigating heat islands.

A binary composite La(OH)3@Ni(OH)2 nanomaterial on carboxyl graphene for an efficient hybrid supercapacitor electrode.

In this work, we present a binary composite of La(OH)3@Ni(OH)2 on carboxyl graphene (La@Ni/CG) as an electrode material. The layered La@Ni/CG double hydroxides (LDHs) were synthesized by a simple electrodeposition method in which La(OH)3 nanoparticles were first adsorbed onto carboxyl graphene and then coated with Ni(OH)2, with different particle shapes due to the large pH change near the cathodic region. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) were used to characterise the as-prepared La@Ni/CG composite. These results showed that the La@Ni/CG composite exhibited improved electrochemical properties, including large specific capacitance (1334.7 F g-1 at 1.4 A g-1) and capacity retention of 90.6% even after 3000 cycles, and excellent rate capability. The improved electrochemical performance of the composite can be attributed to the synergistic effect of surface adsorption and conductive pathways provided by the multiple active species (Ni, La and C) in the La@Ni/CG composite. The results presented in this work provide advances in the efficient design of nanomaterial based electrochemical energy storage devices.

Spatiotemporal variation of ozone pollution and health effects in China.

With the rapid urbanization and industrialization in China, ozone pollution has become increasingly serious and poses a greater threat to human health. In this study, the spatiotemporal distribution of ozone pollution in China's cities and urban agglomerations from 2015 to 2019 was analyzed. The health effects and health economic costs of ozone pollution in China were estimated by applying the environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) model. The results are as follows: (1) ozone pollution was more serious in Chinese urban agglomerations from 2015 to 2019; (2) the hot spots of ozone concentration mainly distributed in the North China Plain, expanding from north to south; the cold spots decreased year by year and were located in the northeast, northwest, and southwest of China, shifting from northwest to southwest; (3) the seasonal average of ozone concentration in China was the highest in summer, followed by spring and autumn, and the lowest in winter; (4) the number of all-cause premature deaths of ozone pollution in China increased slowly from 2015 to 2019, and the average of urban agglomerations was significantly higher than cities, with similar spatial distribution characteristics as ozone concentration; (5) the health economic costs of ozone pollution from 2015 to 2019 slowly expanded to surrounding cities with Beijing, Shanghai, Xi'an, and Chongqing as the centers of high values, while the low value areas decreased year by year and were mainly concentrated in southwest and northeast China. The health economic costs of ozone pollution at urban agglomerations scale were higher in the eastern coastal regions and lower in the northwest inland regions. Thus, this study presents policy recommendations to provide decision-making reference for realizing the inter-regional prevention and control of ozone pollution.

Highly Efficient Low-Concentration Phosphate Removal from Effluents by Recoverable La(OH)3/Foamed Nickel Adsorbent.

Lanthanum-based materials have attained increasing attention because of their high adsorption property of phosphate ions and their environmental harmlessness. However, challenges still remain to improve the phosphate adsorption capacity and find suitable materials for the lanthanum attachment substrate. Nickel foam with characteristics such as excellent uniformity, large specific surface area, high porosity, and low conductivity is considered to be the alternative for the preparation of lanthanum-based adsorption materials. An efficient adsorbent foamed nickel-based La (OH)3 nanowire was first prepared with a facile one-step electrodeposition method. The batch static adsorption tests of simulative wastewater (e.g., coexisting ions and solution pH values) were employed to investigate the phosphate adsorption kinetics and solution matrix effects of the materials. The results indicate that the composite exhibits fast adsorption kinetics within 30 min and high selectivity to phosphate under interference from competing ions. The pH value of wastewater has great influence on the absorption of phosphate, and optimal adsorption capacity can be achieved over a pH 4-6 range. Various findings revealed that the adsorption behavior of lanthanum hydroxide/foamed nickel [La(OH)3/Ni] followed inner-sphere adsorption through the ligand-exchange mechanism. The prepared material is expected to be an enormous potential candidate for the removal of low-concentration phosphorus from effluents.

Advanced asymmetric supercapacitors with a squirrel cage structure Fe3O4@carbon nanocomposite as a negative electrode.

Carbon materials have been used as negative electrodes for supercapacitor applications; nevertheless, owing to the low capacitance, they have limited ability to enhance the supercapacitor electrochemical properties. Here, we employ a facile chemical precipitation method for preparing a squirrel cage structure Fe3O4@carbon nanocomposite. In this architecture, the carbonized crosslinked bovine serum albumin (C) will play critical roles, serving as a skeleton for the deposition of Fe3O4 and a transportation pathway like "high-speed rail" for electrons, maintaining the structural stability as well as accommodating the volume expansion of Fe3O4 and facilitating electron transportation and the electrolyte ion diffusion. The iron oxide nanoparticles (Fe3O4) exhibit superior reversible redox characteristics, hence increasing the supercapacitor performance. Benefiting from a stable structure, an aqueous asymmetric supercapacitor using a CNT@Ni(OH)2 positive electrode (cathode) and Fe3O4@C negative electrode (anode) has also been assembled, which presents a high energy density of 17.3 W h kg-1 at a power density of 700 W kg-1. The strategy for choice of Fe3O4@C composites will provide new opportunities for future supercapacitors with superior cyclability and high power density.

Low-Crystalline FeOOH Nanoflower Assembled Mesoporous Film Anchored on MWCNTs for High-Performance Supercapacitor Electrodes.

Crystalline iron oxides/hydroxides are generally preferred as supercapacitor electrode materials instead of the low-crystalline structure, despite the fact that an amorphous phase could have a comprehensive electrochemical performance owing to its structural disorder. Herein, we present a facile and scalable method for preparing amorphous FeOOH nanoflowers@multi-walled carbon nanotubes (FeOOH NFs@MWCNTs) composites. The resulting hybrid nanoflowers hold a distinctive heterostructure composed of a self-assembled amorphous FeOOH nanofilm on the MWCNTs surface. The low-crystalline 1FeOOH NFs@1MWCNTs composites at pH 8 exhibit a high comprehensive capacitive performance, which may be attributed to the advantageous structural features. In a -0.85 to 0 V vs Ag/AgCl potential window, the prepared hybrid electrode delivers a high specific capacitance of 345 F g-1 at a current density of 1 A g-1, good cycling stability (76.4% capacity retention over 5000 consecutive cycles), and outstanding rate performance (167 F g-1 at 11.4 A g-1). This work may trigger the possibilities of these nanomaterials for further application in supercapacitor electrodes, specifically low-crystalline oxide/hydroxide-based electrode materials.

Sensitive detection of CD147/EMMPRIN and its expression on cancer cells with electrochemical technique.

Cluster of differentiation 147 (CD147), also known as extracellular matrix metalloproteinase inducer (EMMPRIN), plays an essential role in tumor progression and metastasis, the expression of which on cell surface is a critical clinical testing index for cancer therapy. In this work, an electrochemical method to assay CD147/EMMPRIN expression on tumor cell surface is proposed. While the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) catalyzed by horseradish peroxidase (HRP) can be employed for electrochemical measurement, the signal enhancement amplified by gold nanoparticles (GNPs) can be also utilized in this study. Therefore, under optimized conditions, the fabricated biosensor responds linearly to the CD147/EMMPRIN concentration from 125 to 1000 pg/mL with a detection limit as low as 52 pg/mL. High sensitivity can also be achieved for the quantification of breast cancer cells in a linear range from 6.2 × 10(4) to 6.25 × 10(5) cells/mL. Moreover, the CD147/EMMPRIN expressed on a single breast cancer cell can be calculated as 2.57 × 10(4) molecules/cell. The proposed strategy in this study is considerably potential for monitoring the dynamic protein expression on cancer cells and for the effective cancer diagnosis and treatment in the future.

An electrochemical biosensor for the direct detection of oxytetracycline in mouse blood serum and urine.

Oxytetracycline (OTC), a broad-spectrum antibiotic, has been extensively used as a food additive for livestock. Its extensive use has greatly increased the risk of chronic drug abuse and has also increased the risk of the resulting diseases. Therefore, in light of this emerging situation, the detection of OTC in both food and livestock is very important to reduce the risks and for diagnosis purposes . In this work, we have proposed an electrochemical aptasensor to quantify OTC. The biosensor shows considerable sensitivity and selectivity, and it can be easily operated and regenerated. Furthermore, for the first time, we have shown that an electrochemical aptasensor can be directly used to detect OTC in mouse blood serum and urine. This biosensor has the potential to aid in the analysis of residual OTC levels, as well as providing more pharmacokinetic information in the future.