Exploring usage pattern variation of free-floating bike-sharing from a night travel perspective.

Free-floating bike sharing (FFBS) attracts increasing research focusing on usage patterns, determining factors, and integrated transportation. However, existing researchers tend to overlook the variation in usage characteristics over various time ranges, particularly the usage pattern at night. This paper is conducted to fill the gap through a series of analysis approaches on FFSB in Beijing. The characteristics of the usage pattern, including time-varying usage and traveling distance distributions, are initially illustrated. Subsequently, the spatial patterns of FFBS are visualized and thoroughly analyzed in different time ranges and origin-destination (O-D) flows. A statistical model evaluating the environmental effects of FFBS trips revealed the source of FFBS usage. In addition to focusing on the nighttime, the usage patterns varying day and night are compared through the analysis. The findings explain the usage pattern variation and the unique pattern at night, providing valuable insight for improving the management of the FFBS system.

MiR-18a affects hypoxia induced glucose metabolism transition in HT22 hippocampal neuronal cell line through the Hif1a gene.

Hypoxia can cause a variety of diseases, including ischemic stroke and neurodegenerative diseases. Within a certain range of partial pressure of oxygen, cells can respond to changes in oxygen. Changes in oxygen concentration beyond a threshold will cause damage or even necrosis of tissues and organs, especially for the central nervous system. Therefore, it is very important to find appropriate measures to alleviate damage. MiRNAs can participate in the regulation of hypoxic responses in various types of cells. MiRNAs are involved in regulating hypoxic responses in many types of tissues by activating the hypoxia-inducible factor (HIF) to affect angiogenesis, glycolysis and other biological processes. By analyzing differentially expressed miRNAs in hypoxia and hypoxia-related studies, as well as the HT22 neuronal cell line under hypoxic stress, we found that the expression of miR-18a was changed in these models. MiR-18a could regulate glucose metabolism in HT22 cells under hypoxic stress by directly regulating the 3'UTR of the Hif1a gene. As a small molecule, miRNAs are easy to be designed into small nucleic acid drugs, so this study can provide a theoretical basis for the research and treatment of nervous system diseases caused by hypoxia.

Activities of Family 18 Chitinases on Amorphous Regenerated Chitin Thin Films and Dissolved Chitin Oligosaccharides: Comparison with Family 19 Chitinases.

Changes in mass and viscoelasticity of chitin layers in fungal cell walls during chitinase attack are vital for understanding bacterial invasion of and human defense against fungi. In this work, regenerated chitin (RChitin) thin films mimicked the fungal chitin layers and facilitated studies of degradation by family 18 chitinases from Trichoderma viride (T. viride) and family 19 chitinases from Streptomyces griseus (S. griseus) that possessed chitin-binding domains (CBDs) that were absent in the family 18 chitinases. Degradation was monitored via a quartz crystal microbalance with dissipation monitoring (QCM-D) in real time at various pH and temperatures. Compared to substrates of colloidal chitin or dissolved chitin derivatives and analogues, the degradation of RChitin films was deeply affected by chitinase adsorption. While the family 18 chitinases had greater solution activity on chitin oligosaccharides, the family 19 chitinases exhibited greater surface activity on RChitin films, illustrating the importance of CBDs for insoluble substrates.

Hypoxia-Induced Downregulation of miR-29 in Renal Tumor Cells Affects Collagen IV Subunit Expression through Multiple Sites.

Multiple tumor exacerbations and treatment procedures, such as extracellular matrix remodeling, metabolic reprogramming, immunological evasion, and resistance to chemotherapy and radiotherapy, are influenced by intratumoral hypoxia. It is becoming increasingly clear how hypoxia interacts with the extracellular matrix and how this affects the growth of cancer. We analyzed the published sequencing results of hypoxia-stressed mouse kidney tumor cells and found that the expression of miR-29b was significantly downregulated. There are several sites that are complementary to the miR-29 seed sequence in the 3' non-coding regions (3'UTRs) of various extracellular matrix-related genes, including collagen IV. We analyzed the sequences of the 3'UTRs of different subunits of collagen IV in different species and constructed the corresponding phylogenetic trees. We found that the 3'UTRs of Col4a1 and Col4a4 may have been subjected to particular evolutionary pressures. By cloning the 3'UTRs of collagen IV subunits into the psiCHECKTM-2 vector, we found that seven of the eight sites in the Col4a3-Col4a6 gene complementary to miR-29 were significantly repressed by miR-29a, b (except for the 7774-7781 of Col4a3 gene). The inhibitory efficiency of miR-29a, b on these seven sites was between 27% and 57%. The research on the regulation of miR-29 and extracellular matrix by hypoxia can provide a theoretical basis for tumor and fibrosis research and treatment.

Microwave-assisted preparation of poly(ionic liquids)-modified polystyrene magnetic nanospheres for phthalate esters extraction from beverages.

The fabrication of novel poly(ionic liquids)-modified polystyrene (PSt) magnetic nanospheres (PILs-PMNPs) by a one-pot miniemulsion copolymerization reaction was achieved through an efficient microwave-assisted synthesis method. The morphology, structure, and magnetic behavior of the as-prepared magnetic materials were characterized by using transmission electron microscopy, vibrating sample magnetometry, etc. The magnetic materials were utilized as sorbents for the extraction of phthalate esters (PAEs) from beverage samples followed by high-performance ultrafast liquid chromatography analysis. Significant extraction parameters that could affect the extraction efficiencies were investigated particularly. Under optimum conditions, good linearity was obtained in the concentration range of 0.5-50 (dimethyl phthalate), 0.3-50 (diethyl phthalate), 0.2-50 (butyl benzyl phthalate), and 0.4-50 µg/L (di-n-butyl phthalate), with correlation coefficients R2  > 0.9989. Limits of detection were in the range 125-350 pg. The proposed method was successfully applied to determine PAEs from beverage samples with satisfactory recovery ranging from 77.8 to 102.1% and relative standard deviations ranging from 3.7 to 8.4%. Comparisons of extraction efficiency with PSt-modified MNPs as sorbents were performed. The results demonstrated that PILs-PMNPs possessed an excellent adsorption capability toward the trace PAE analytes.

Preparation of novel ionic-liquid-modified magnetic nanoparticles by a microwave-assisted method for sulfonylurea herbicides extraction.

Ionic liquids immobilized on magnetic nanoparticles were prepared by an efficient microwave-assisted synthesis method, and the properties of the ionic liquids were tuned based on the aromatic functional modification of its anion through a simple metathesis reaction. The novel as-synthesized magnetic materials were characterized by various instrumental techniques. The magnetic nanoparticles have been utilized as adsorbents for the extraction of four sulfonylurea herbicides in tea samples, in combination with high-performance liquid chromatography analysis. Significant extraction parameters, including type and volume of desorption solvent, extraction time, amount of adsorbent, and ionic strength were investigated. Under the optimum conditions, good linearity was obtained in the concentration range of 1-150 µg/L for metsulfuron-methyl and bensulfuron-methyl, and 3-150 µg/L for sulfometuron-methyl and chlorimuron-ethyl, with correlation coefficients R2 > 0.9987. Low limits of detection were obtained ranging from 0.13 to 0.81 µg/L. The relative standard deviations were 1.8-3.9%. Comparisons of extraction efficiency with conventional solid-phase extraction equipped with a commercial C18 cartridge were performed. Results indicated that magnetic solid-phase extraction is simple, time-saving, efficient and inexpensive with the reusability of adsorbents. The proposed method has been successfully used to determine sulfonylurea herbicides from tea samples with satisfactory recoveries of 80.5-104.2%.