Enhanced hemocompatibility and antibacterial activity of biodegradable poly(ester-urethane) modified with quercetin and phosphorylcholine for durable blood-contacting applications.

This work developed innovative poly(ester-urethane) materials double-modified by quercetin (QC) and phosphorylcholine (PC) with improved antibacterial activity and hemocompatibility. The functional monomer of PC-diol was first synthesized via a click reaction between 2-methacryloyloxyethyl phosphorylcholine and α-thioglycerol; the NCO-terminated prepolymer was subsequently prepared by a one-pot condensation method of PC-diol, poly(ε-caprolactone) diol, and excess isophorone diisocyanate; finally, the prepolymer was chain-extended with QC to produce the linear products (PEU-PQs). 1H NMR, FT-IR, and XPS techniques confirmed the successful introduction of PC and QC, and the in-depth characterization of the cast PEU-PQ films was carried out. Although a low crystallinity was demonstrated by XRD and thermal analysis, the films exhibited excellent tensile stress and stretchability due to the interchain multiple hydrogen bonds. The introduction of PC groups enhanced the surface hydrophilicity, water absorption, and the in vitro hydrolytic degradation rate of the film materials. Inhibition zone tests presented that the QC-based PEU-PQs had effective antibacterial activity against E. coli and S. aureus. The biological evaluations of the materials were performed in vitro by protein absorption, platelet adhesion, and cytotoxic test and in vivo by subcutaneous implantation, which demonstrated superior surface hemocompatibility and biocompatibility. Collectively, the PEU-PQ biomaterials hold a prospective application in durable blood-contacting devices.

Review on Vehicle Detection Technology for Unmanned Ground Vehicles.

Unmanned ground vehicles (UGVs) have great potential in the application of both civilian and military fields, and have become the focus of research in many countries. Environmental perception technology is the foundation of UGVs, which is of great significance to achieve a safer and more efficient performance. This article firstly introduces commonly used sensors for vehicle detection, lists their application scenarios and compares the strengths and weakness of different sensors. Secondly, related works about one of the most important aspects of environmental perception technology-vehicle detection-are reviewed and compared in detail in terms of different sensors. Thirdly, several simulation platforms related to UGVs are presented for facilitating simulation testing of vehicle detection algorithms. In addition, some datasets about UGVs are summarized to achieve the verification of vehicle detection algorithms in practical application. Finally, promising research topics in the future study of vehicle detection technology for UGVs are discussed in detail.

Facile Method for Surface-Grafted Chitooligosaccharide on Medical Segmented Poly(ester-urethane) Film to Improve Surface Biocompatibility.

In the paper, the chitooligosaccharide (CHO) was surface-grafted on the medical segmented poly(ester-urethane) (SPU) film by a facile two-step procedure to improve the surface biocompatibility. By chemical treatment of SPU film with hexamethylene diisocyanate under mild reaction condition, free -NCO groups were first introduced on the surface with high grafting density, which were then coupled with -NH2 groups of CHO to immobilize CHO on the SPU surface (SPU-CHO). The CHO-covered surface was characterized by FT-IR and water contact angle test. Due to the hydrophilicity of CHO, the SPU-CHO possessed higher surface hydrophilicity and faster hydrolytic degradation rate than blank SPU. The almost overlapping stress-strain curves of SPU and SPU-CHO films demonstrated that the chemical treatments had little destruction on the intrinsic properties of the substrate. In addition, the significant inhibition of platelet adhesion and protein adsorption on CHO-covered surface endowed SPU-CHO an outstanding surface biocompatibility (especially blood compatibility). These results indicated that the CHO-grafted SPU was a promising candidate as blood-contacting biomaterial for biomedical applications.

The influence of wind speed on airflow and fine particle transport within different building layouts of an industrial city.

In atmospheric environment, the layout difference of urban buildings has a powerful influence on accelerating or inhibiting the dispersion of particle matters (PM). In industrial cities, buildings of variable heights can obstruct the diffusion of PM from industrial stacks. In this study, PM dispersed within building groups was simulated by Reynolds-averaged Navier-Stokes equations coupled Lagrangian approach. Four typical street building arrangements were used: (a) a low-rise building block with Height/base H/b = 1 (b = 20 m); (b) step-up building layout (H/b = 1, 2, 3, 4); (c) step-down building layout (H/b = 4, 3, 2, 1); (d) high-rise building block (H/b = 5). Profiles of stream functions and turbulence intensity were used to examine the effect of various building layouts on atmospheric airflow. Here, concepts of particle suspension fraction and concentration distribution were used to evaluate the effect of wind speed on fine particle transport. These parameters showed that step-up building layouts accelerated top airflow and diffused more particles into street canyons, likely having adverse effects on resident health. In renewal old industry areas, the step-down building arrangement which can hinder PM dispersion from high-level stacks should be constructed preferentially. High turbulent intensity results in formation of a strong vortex that hinders particles into the street canyons. It is found that an increase in wind speed enhanced particle transport and reduced local particle concentrations, however, it did not affect the relative location of high particle concentration zones, which are related to building height and layout. IMPLICATIONS: This study has demonstrated the height variation and layout of urban architecture affect the local concentration distribution of particulate matter (PM) in the atmosphere and for the first time that wind velocity has particular effects on PM transport in various building groups. The findings may have general implications in optimization the building layout based on particle transport characteristics during the renewal of industrial cities. For city planners, the results and conclusions are useful for improving the local air quality. The study method also can be used to calculate the explosion risk of industrial dust for people who live in industrial cities.