Reducing traffic violations in the online food delivery industry-A case study in Xi'an City, China.

Online food delivery (OFD) is one of the top industries in the Online-to-offline (O2O) commerce sector. Deliverymen need to complete a large number of delivery orders in limited default time every day, which cause high working stress to them. Therefore, a high level of traffic violations and crashes by deliverymen and corresponding negative impact on public safety are observed.

[Pollution and Source Analysis of Heavy Metal in Surface Dust from Xi'an University Campuses].

Surface dust samples were collected from university campuses in Xi'an, and X-ray fluorescent spectrometry was used to determine the contents of nine heavy metals (Mn, As, Pb, Cr, Co, Ni, Cu, V, and Zn). Enrichment factors were subsequently used to determine the enrichment degree of each element and the preliminary determination of the pollution sources. The R programming language and SPSS were used for cluster analysis and principal components analysis to identify the pollution sources.

[Source Identification and Pollution Characteristics of Heavy Metals in Suspended Particles of Urban Road Dust from Xingtai City].

Fifty dust samples were collected from Xingtai City to study the source characteristics of heavy metals in suspended particles of urban road dust from industrial enterprise transformation cities. The contents of Cr, Mn, Co, Ni, Cu, Zn, As, and Pb in particles of urban road dust smaller than 100 μm were determined by X-ray fluorescence spectrometry, and their pollution levels were assessed by enrichment factor. The possible sources of heavy metals measured in the dust were identified by multivariate statistical analysis methods including correlation analysis, principal component analysis, and cluster analysis.

[Assessment of Pollution, Sources, and Risks of Polycyclic Aromatic Hydrocarbons in Soil from Urban Parks in Xi'an City, China].

A total of seventeen surface soil samples were collected from urban parks in Xi'an city. The concentration of sixteen priority polycyclic aromatic hydrocarbons (PAHs) were analyzed by high performance liquid chromatography (HPLC). In addition, the composition, source, pollution level and a risk assessment of PAHs in surface soil of park were evaluated.

[Source Apportionment of Soil Heavy Metals in City Residential Areas Based on the Receptor Model and Geostatistics].

The soils from residential areas of Xi'an city were selected as a case area. The absolute principal component scores-multivariate linear regression (APCS-MLR) model and the ordinary kriging interpolation were combined to identify and apportion the pollution sources of soil heavy metals (As, Ba, Co, Cu, Mn, Ni, Pb, Sr, Zn,V), the percentage of contribution of every source for every element, and the spatial distribution characteristics of contribution rates. Compared with the background values of cinnamon, which is the main soil type in Xi 'an, the accumulation levels of Pb, Cu, Sr, Co, Zn, Ba, Ni, As, Mn, V in soil of urban residential areas in Xi'an city decreased in turn.

[Contamination Levels and Source Analysis of Heavy Metals in the Finer Particles of Urban Road Dust from Xi'an, China].

Road dust samples were collected from four different functional areas in Xi'an City, i.e., an educational area, a residential area, a park area, and a traffic area, to study the influence of intensive human activities on local urban environmental quality.

Copper-Catalyzed Functionalizations of C with Amino Alcohols.

CuI-catalyzed diverse functionalizations of C with amino alcohols with aerobic oxygen as the sole oxidant have been explored. For 2-/3-amino alcohols, an aminooxygenation reaction occurs to generate fulleromorpholine and fullerooxazepane derivatives. When a tethered furan ring exists, a further intramolecular [4 + 2] reaction with the neighboring double bond occurs to furnish the cis-1 products.

[Distribution, Source and Human Exposure of Phthalic Acid Esters (PAEs) in Surface Dust in Urban Area of Xi'an City, China].

A total of 58 surface dust samples were collected in urban area of Xi'an City. High Performance Liquid Chromatography (HPLC) was used to analyze the concentrations of six phthalic acid esters (PAEs) listed as priority pollutants by United States Environmental Protection Agency (U.S.

[Distribution Characteristics and Source Analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Dust of Xi'an City, China].

A total of 58 surface dust samples were collected from Xi'an city. The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were analyzed by gas chromatography with a flame ionization detector (GC-FID). At the same time, the distribution and sources of PAHs in surface dust were studied.

Cu(OAc)2-promoted reaction of [60]fullerene with primary amines or diamines.

The Cu(OAc)2-promoted reaction of C60 with easily available primary amines allows the concise preparation of aziridinofullerenes. Both alkyl and aryl amines are suitable in this reaction. Moreover, the Cu(OAc)2-promoted reaction of C60 with diamines affords C60-fused cyclic 1,2-diaminated fullerenes.

[DNA aptamer selection in vitro for determining ketamine by FluMag-SELEX].

Objective: To select specific DNA aptamer for determining ketamine by FluMag-SELEX.

Methods: Based on magnetic beads with tosyl surface modification as solid carrier and ketamine as target, a random ssDNA library with total length of 78 bp in vitro was compounded. After 13 rounds screening, DNA cloning and sequencing were done.

Lewis base-catalyzed reaction of aziridinofullerene with ureas for the preparation of fulleroimidazolidinones.

The Lewis base-catalyzed double nucleophilic substitution reaction of N-tosylaziridinofullerene with various ureas allows the easy preparation of fulleroimidazolidinones with a high tolerance for functional groups. Alkyl-substituted ureas show better reactivity than aryl-substituted ureas.

Hypervalent iodine reagent mediated diamination of [60]fullerene with sulfamides or phosphoryl diamides.

A hypervalent iodine-promoted intermolecular diamination reactions of C60 with sulfamides or phosphoryl diamides affords two classes of novel C60-fused cyclic sulfamide or phosphoryl diamide derivatives. The reaction between C60 and sulfamides can be effectively controlled to selectively synthesize diamination products or azafulleroids under PhIO/I2 or PhI(OAc)2/I2 conditions, respectively. Moreover, phosphoryl diamides were first used as an amine source in the diamination of alkenes.

BF3·Et2O- or DMAP-catalyzed double nucleophilic substitution reaction of aziridinofullerenes with sulfamides or amidines.

BF3·Et2O-catalyzed double nucleophilic substitution reaction of N-tosylaziridinofullerene with sulfamides has been exploited for the easy preparation of cyclic sulfamide-fused fullerene derivatives. Moreover, the Lewis base catalyzed double amination of N-tosylaziridinofullerene, with amidines as the diamine source, is demonstrated for the first time. The present methods provide new routes to cyclic 1,2-diaminated [60]fullerenes.

Hypervalent iodine reagent mediated reaction of [60]fullerene with amines.

The hypervalent iodine reagent mediated reaction of C60 with various readily available amines for the easy preparation of iminofullerenes has been developed. The reaction between C60 and sulfonamides can be effectively controlled to selectively synthesize azafulleroids or aziridinofullerenes under PhI(OAc)2/I2 or PhIO/I2/CuCl/lutidine conditions, respectively. For phosphamide and urea, only one isomer is obtained.

I(2)-catalyzed direct α-hydroxylation of β-dicarbonyl compounds with atmospheric oxygen under photoirradiation.

An I2-catalyzed hydroxylation of β-dicarbonyl moieties using air as the oxidant under photoirradiation has been developed for the easy preparation of α-hydroxy-β-dicarbonyl compounds. The transformation was completed with only 1 mol % of I2. With α-unsubstituted malonates, the hydroxylated dimerization product was afforded as the predominant product along with a minor product, α,α-dihydroxyl malonate.

[Correlativity study of the distribution of soil magnetic susceptibility and the heavy metal contents in Xi'an City].

The magnetic susceptibility and the concentrations of Co, Cr, Cu, Pb, Sn, Sr and Ba in topsoil samples from Xi'an City were measured to study their spatial distribution and their correlation in this study. The results show that the concentrations of all measured heavy metals are higher than their background values in Cinnamon topsoil, which is the main soil type of Xi'an City. The heavy metals concentrations and the magnetic susceptibility of the studied samples display moderate variance.

[Content, source and speciation of heavy metal elements of street dusts in Baoji City].

Heavy metal concentrations in street dust of Baoji City were investigated by using X-Ray fluorescence spectrometry (XRF) and atomic adsorption spectrometry (AAS). The results show that the mean concentrations of Cu, Pb, Zn, Mn, Co, Ni, Cr and Cd are 123.2, 408.

[Sources and potential risk of heavy metals in roadside soils of Xi' an City].

Based on the X-Ray fluorescence spectroscopic measurement of heavy metals concentration in roadside soil samples from Xi' an City, and by the methods of principal component analysis, cluster analysis, and correlation analysis, this paper approached the possible sources of heavy metals in the roadside soils of the City. In the meantime, potential ecological risk index was used to assess the ecological risk of the heavy metals. In the roadside soils, the mean concentrations of Co, Cr, Cu, Mn, Ni, Pb, and Zn were higher than those of the Shaanxi soil background values.

[Effects of Azone of different concentrations on percutaneous absorption of baicalin in vitro].

Objective: To study the effects of azone on the percutaneous absorption of baicalin in vitro.

Methods: Using the skin of nude mice as the cutaneous barrier, the rate constants of percutaneous absorption of baicalin at various concentrations of Azone were determined.

Results: The rate constants were 76.