Characteristics of urban network and city functions in the Yangtze River Delta Region: A multi-scale perspective.

The development of cities and regions emerges from the complex associations at various spatial levels, highlighting the importance of a multi-scale approach to analyzing regional urban networks. This study attempts to establish a new analysis framework encompassing national, regional, and local dimensions by employing a population flow network in the Yangtze River Delta in China. It explores the inter-city connections and spatial structures of regional urban networks as well as the correlations and differentiations of urban functions under multi-scale interaction. The results indicate that: (1) Regional network demonstrates notable multi-scale interactions with an explicit hierarchical structure; (2) The roles and positions of different cities vary significantly across scales due to economic, administrative, locational, and transportation differences; (3) Different city types can drive their evolution by navigating through rescaling in a diverse multi-scale environment; (4) A positive correlation is observed when comparing the functional behaviors of cities across various scales. This study provides insights for cities to identify their strategic roles and adapt development strategies within the wider network framework, offering theoretical and practical contributions to multi-scale urban networks analysis.

Julichrome derivatives and gliotoxin from a soil derived Streptomyces sp.

Six julichrome derivatives including a new monomeric julichrome named as julichrome Q10 (1), and previous reported julichrome Q6 (2), julichrome Q6.6 (4), julichrome Q3.5 (5), julichrome Q5.6 (6), julichrome Q2.3 (7), along with a diketopiperazine gliotoxin (3) were isolated from a soil derived strain Streptomyces sp. The structures of these compounds were identified by HR-ESI-MS, UV, IR and NMR methods. The isolated compounds were tested for their in vitro cytotoxicity against human hepatocarcinoma HepG-2 and SMMC-7721 cell lines, human breast cancer MCF-7 and MDA-MB-231 cell lines, and human normal heptical LO2 cell line. Gliotoxin (3) showed the most cytotoxic activity against the tested tumor cell lines, with IC50 values ranging from 0.11 to 1.45 µM. Julichrome Q6.6 (4) displayed selective cytotoxic activity against SMMC-7721, MCF-7 and MDA-MB-231 cell lines.

Identification and expression analysis of an olfactory receptor gene family in green plant bug Apolygus lucorum (Meyer-Dür).

Olfactory receptors are believed to play a central role in insects host-seeking, mating, and ovipositing. On the basis of male and female antennal transcriptome of adult Apolygus lucorum, a total of 110 candidate A. lucorum odorant receptors (AlucOR) were identified in this study including five previously annotated AlucORs. All the sequences were validated by cloning and sequencing. Tissue expression profiles analysis by RT-PCR indicated most AlucORs were antennal highly expressed genes. The qPCR measurements further revealed 40 AlucORs were significantly higher in the antennae. One AlucOR was primarily expressed in the female antennae, while nine AlucORs exhibited male-biased expression patterns. Additionally, both the RPKM value and RT-qPCR analysis showed AlucOR83 and AlucOR21 were much higher abundant in male antennae than in female antennae, suggesting their different roles in chemoreception of gender. Phylogenetic analysis of ORs from several Hemipteran species demonstrated that most AlucORs had orthologous genes, and five AlucOR-specific clades were defined. In addition, a sub-clade of potential male-based sex pheromone receptors were also identified in the phylogenetic tree of AlucORs. Our results will facilitate the functional studies of AlucORs, and thereby provide a foundation for novel pest management approaches based on these genes.

Determination of water content in organic solvents by naphthalimide derivative fluorescent probe.

A new fluorescence dye, N-amino-4-(2-hydroxyethylamino)-1,8-naphthalimide (AHN), based on 4-bromo-1,8-naphthalic anhydride was synthesized as a fluorescence probe for determining water content in organic solvents. Changing from a non-polar to a polar solvent increases the solvent interaction with excitation spectrum and emission spectrum shifts to longer wavelengths. The fluorescence intensity of the probe decreased with the increasing concentration of water. In the range of 0.00-4.00% (v/v), the AHN fluorescence intensity changed as a linear function of water content. The detection limits were 0.019, 0.038, and 0.060% for dioxane, acetonitrile and ethanol, respectively.