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  • Author: Qian Ma x
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Abstract

This study was aimed to develop a quick detection method to test aldehydes and ketones in textiles in order to control the quality of automotive textiles in the development process from fabric production to end-use in vehicles. In this study, a pretreatment of samples was applied to simulate the actual environment of textiles used in vehicles. Collected volatiles were reacted with 2,4-dinitrophenylhydrazine and then eluted with acetonitrile tetrahydrofuran. The eluent was analyzed with high-performance liquid chromatography. Findings showed more than 90% volatiles could be detected in the established method; the lowest determination limit was 0.0297 mg/mL; and the lowest quantification limit was 0.0991 mg/mL, which meant sensitivity and capability of the method were high. Regression coefficients of linear models between volatile concentrations and chromatographic peak characteristics were >0.995, indicating that the method could effectively and efficiently determine the contents of volatiles in automotive textiles.

Abstract

Prebiotics can play an important role in functional foods. In this paper, casein and five probiotics were selected to study the effects on ACE inhibitory peptides in fermented milk of L. bulgaricus LB6 through Plackett-Burman design, so as to improve the production of ACE inhibitory peptides. The results showed that xylooligosaccharides (XOS), fructosaccharide (FOS) and inulin had the most significant effect on the yield of ACE inhibitory peptides. Optimization added the amount of the three prebiotics added, that is, the amount of XOS added was 0.7%, the amount of FOS added was 1.1%, and the amount of inulin added was 0.7%. It provides a basis for subsequent optimization experiments.

Abstract

Background: Single lung Fontan procedure has been performed in patients with a congenital heart disease and a single functional lung. The procedure has not been reported in China.

Objective and Methods: We reported on the case of a 6-year-old child who had a single functional right ventricle, and an atretic left pulmonary artery, who underwent a successful Fontan operation into the single right pulmonary artery. The literature of Fontan procedure in the presence of a single lung is reviewed.

Results: The patient to relate the procedure well and had uneventful recovery. The patient has been followed up for more than two years with reasonable hemodynamics.

Conclusion: The single lung Fontan operation is possible with good outcomes. More patients and longer follow up will be required to standardize the strategies and to document utility of this procedure.

Abstract

The quasi-static tensile damage behavior of one type of layer-to-layer 3-Dimensional Angle-interlock Woven Composite (3DAWC) was tested and analyzed in this paper. Incorporated with the acoustic emission (AE) events monitoring, the mechanical behavior of the 3DAWC under tensile loading condition was characterized. The Load-Extension curve, Load/AE events-Time curves occurred during the entire testing process and tensile damage modes were recorded to characterize and summarize the mechanical properties and damage mechanism of the 3DAWC subjected to tensile loading. It was found that the tensile damage of the 3DAWC could be summarized into 3 steps. And each step has a distinct primary damage mode. Moreover, the resin cracks, resin-yarn interface debonding and yarn breakages were the main damage modes for the 3DAWC.

Abstract

The most attractive structural feature of the three-dimensional (3D) angle-interlock woven structure is that the straight weft yarns are bundled by the undulated warp yarns, which induces the overall good structural stability and a stable fabric structure. Thus the 3-D angle-interlock woven composite (3DAWC) prepared by the vacuum-assisted resin transfer molding (VARTM) curing process has excellent mechanical properties by using the fabric and epoxy resin as the reinforcement and matrix, respectively. The low-velocity impact damage properties of the composites under different drop-weight energies (70, 80, and 100 J) were tested experimentally. The load–displacement curves, energy–time curves, and the ultimate failure modes were obtained to analyze the performance of resistance to low-velocity impact, as well as the impact energy absorption effect and failure mechanism, especially the structural damage characteristics of the 3DAWC subjected to the low-velocity impact of drop weight. By analyzing the obtained experimental results, it is found that the fabric reinforcement is the primary energy absorption component and the impact energy mainly propagates along the longitudinal direction of the yarns, especially the weft yarn system, which is arranged in a straight way. In addition, as the impact energy increases, the energy absorbed and dissipated by the composite increases simultaneously. This phenomenon is manifested in the severity of deformation and damage of the material, i.e., the amount of deformation and size of the damaged area.

Abstract

Three-dimensional angle-interlock woven composites (3DAWCs) are widely used for their excellent mechanical properties. The most significant feature is the existence of the undulated warp yarns along the thickness direction, which makes it interesting to study the mechanical properties in the warp direction. The quasi-static tensile behavior of a layer-to-layer 3DAWC along the undulated warp direction was studied by experimental and finite element analysis (FEA) methods. Based on the experimental results, the typical failure mode involving fibers, resin, and their interfaces was found. According to the FEA results, the stress concentration effect, key structural regions, and microstructural (yarn and resin) damage mechanism were obtained, which provided effective guidance for structural optimization design of the 3DAWC with stronger tensile resistance performance. In addition, the three-step progressive failure process of the 3DAWC under quasi-static tensile load was also described at the “yarn–resin” microstructural level.

Abstract

The aim of this study was to identify an effective flavonoid that could improve the intracellular accumulation of ritonavir in human brain-microvascular endothelial cells (HBMECs). An in vivo experiment on Sprague-Dawley rats was then designed to further determine the flavonoid’s impact on the pharmacokinetics and tissue distribution of ritonavir. In the accumulation assay, the intracellular leve l of ritonavir was increased in the presence of 25 mmol L−1 of flavonoids in HBMECs. Quercetin showed the strongest effect by improving the intracellular accumulation of ritonavir by 76.9 %. In the pharmacokinetic study, the presence of quercetin in the co-administration group and in the pretreatment group significantly decreased the area under the plasma concentration-time curve (AUC 0–t) of ritonavir by 42.2 % (p < 0.05) and 53.5 % (p < 0.01), and decreased the peak plasma concentration (c max) of ritonavir by 23.1 % (p < 0.05) and 45.8 % (p < 0.01), respectively, compared to the control group (ritonavir alone). In the tissue distribution study, the ritonavir concentration in the brain was significantly increased 2-fold (p < 0.01), during the absorption phase (1 h) and was still significantly higher (p < 0.05) during the distribution phase (6 h) in the presence of quercetin.