Research on Dust Effect for MEMS Thermal Wind Sensors

This communication investigated the dust effect on microelectromechanical system (MEMS) thermal wind sensors, with an aim to evaluate performance in practical applications. An equivalent circuit was established to analyze the temperature gradient influenced by dust accumulation on the sensor’s surface. The finite element method (FEM) simulation was carried out to verify the proposed model using COMSOL Multiphysics software. In experiments, dust was accumulated on the sensor’s surface by two different methods. The measured results indicated that the output voltage for the sensor with dust on its surface was a little smaller than that of the sensor without dust at the same wind speed, which can degrade the measurement sensitivity and accuracy. Compared to the sensor without dust, the average voltage was reduced by about 1.91% and 3.75% when the dustiness was 0.04 g/mL and 0.12 g/mL, respectively. The results can provide a reference for the actual application of thermal wind sensors in harsh environments

Improvement in Mechanical Properties of Al2024 Alloy Using Mechanical Working and Heat Treatment

Extrusion speed has a significant influence on the extrusion temperature, microstructure and mechanical properties of the material in the repetitive continuous extrusion forming (RCEF) process. In this work, the mechanical properties of Al2024 were improved by adjusting the speed (with a general range of 2–10 rpm) of repetitive continuous extrusion and applying subsequent heat treatment. During the RCEF process, an increase in the extrusion speed from 4 to 8 rpm was found to increase the extrusion temperature and then enhance the solid solution function. The grain size was affected by the combined effect of deformation speed and its induced temperature. A high-strength Al2024 (ultimate tensile strength of 497.6 MPa) with good elongation (12.93%) was obtained by increasing the extrusion speed and conducting solid solution and artificial aging treatments. The main strengthening mechanisms could be attributed to finer grain size and a larger amount of S (Al2CuMg) precipitates

Design, synthesis, and antiviral activities of myricetin derivatives containing phenoxypyridine

A series of myricetin derivatives containing phenoxypyridine structure were designed and synthesized on the basis of the natural product myricitrin, which were structurally characterized on NMR and HRMS. The results of antiviral activity tests showed that some of the target compounds exhibited better inhibitory effects. Among them, B19 and B21 showed better curative activity with EC50 values of 195.67 and 173.64 μg/mL, respectively, which were superior to that of the control agent ningnanmycin(NNM) (238.30 μg/mL). B21 showed better protective activity with EC50 value of 236.37 μg/mL, which was better than that of the control agent NNM (269.89 μg/mL). The results of microcalorimetry showed that B1, B19 and B21 had good binding affinity with tobacco mosaic virus capsid protein (TMV-CP), and the Kd values were 0.059, 0.093 and 0.069 μM, which was higher than that of NNM (Kd = 2.78 μM). The molecular docking results showed that the hydrogen bond lengths between B1, B21 and the key amino acid residues of TMV-CP were shorter and with more tightly bound than those of NNM. In B21-treated tobacco leaves, chlorophyll content and superoxide dismutase (SOD) activity were significantly elevated, indicating that B21 can participate in regulating plant photosynthesis as well as defense enzymes and inducing plants to improve disease resistance

Design, synthesis, and antifungal activities of chalcone derivatives containing piperidine and sulfonamide moiety

A series of chalcone derivatives containing piperidine sulfonamide were designed and synthesized from natural chalones, and their structures were characterized on NMR and HRMS. In vitro antifungal activity test results showed that most of the target compounds exhibited good antifungal activities against a variety of fungi in vitro. X17 showed an excellent antifungal activity against S. sclerotiorum, Phomopsis sp, P. capsica with EC50 values of 10.43, 10.78, 12.02 µg/mL, respectively. It was better than those of azoxystrobin (19.34, 18.21, 63.44 µg/mL). In vivo antifungal activity test showed that X17 at the concentration of 200 µg/mL had better curative activities on rape leaves (90.8 %) than that of azoxystrobin (86.6 %). The protective activities on kiwifruits (88.3 %) were better than that of azoxystrobin (86.1 %). Mechanical studies showed that X17 inhibited the normal hypha growth by disrupting the cell membrane of S. sclerotiorum

Ligustrazine Inhibits Cartilage Endplate Hypertrophy via Suppression of TGF-β1

CEP hypertrophy is one of the characteristics of intervertebral disc degeneration (IDD). LIG exerts a protective effect on IDD in animal model. The effect of LIG on CEP hypertrophy is further investigated in the present study. Cells were isolated from hypertrophic samples obtained from patients during vertebral fusion surgery. Cellular proliferation and the expression of type I collagen (Col I) and TGF-β1 were tested. In the bipedal rats, the edges of the CEP and the sizes of noncartilaginous outgrowth, as well as the expression of osteogenic markers, Col1a, ALP, Runx2, and TGF-β1, were detected. Within two passages, the condensed hypertrophic CEP cells exhibited osteogenic capacity by bony-like nodules and ALP positive staining, along with increased expression of Col I and TGF-β1. LIG inhibited proliferation of CEP cells and downregulated the expression of Col I and TGF-β1 in vitro. Furthermore, LIG attenuated CEP hypertrophy on the lumbar spine of bipedal rats by reducing Col1a, ALP, Runx2, and TGF-β1 mRNA expression and TGF-β1 distribution in vivo. We concluded LIG exerted a preventive effect on CEP hypertrophy via suppression of TGF-β1 levels. This information could be used to develop alternative therapeutic methods to treat spinal CEP hypertrophy

Novel flavonoid derivatives containing 1,2,4-triazolo[4,3-a]pyridine as potential antifungal agents: Design, synthesis, and biological evaluation

A series of flavonoid derivatives containing 1,2,4-triazolo[4,3-a]pyridine were designed, synthesized and evaluated for their antifungal activity. Bioactivity tests showed that some target compounds exhibited the strong antifungal activity against Botrytis cinerea (B. cinerea), Sclerotinia sclerotiorum (S. sclerotiorum), and Phomopsis sp. Among them, the half maximal effective concentration (EC50) value of S2 against B. cinerea was 3.3 μg/mL, which was less than that of the control drug azoxystrobin (21.0 μg/mL). The EC50 value of S2 against S. sclerotiorum was 12.7 μg/mL, which was better than that of azoxystrobin (28.1 μg/mL). In addition, the in vivo protective and curative activities of S2 against blueberry were 92.0 and 79.8 % at 200 μg/mL, respectively, which were higher than those of the control drug azoxystrobin (89.4 and 71.7 %). Scanning electron microscopy (SEM) and spore germination experiments showed that S2 could not only cause the mycelium damage but also inhibited the spore germination. Fluorescence microscopy (FM) observation, relative electrical conductivity measurement and cytoplasmic leakage assays indicated that S2 could affect cell membrane integrity by inducing lipid peroxidation and increasing cell membrane permeability as well as causing leakage of cytoplasmic contents. These results show that flavonoid derivatives containing 1,2,4-triazolo[4,3-a]pyridine had excellent inhibitory effects on B. cinerea, providing another supplement for the development of new pesticides

Analysis of the Genetic Diversity and Mating System of the Endangered Plant <i>Keteleeria davidiana</i> var. <i>calcarea</i>

Keteleeria davidiana var. calcarea is an endangered plant endemic to China. It is mainly distributed in the karst areas of the Guangxi and Guizhou Provinces. It is characterized by small populations and intermittent distribution. This study aimed to explore the genetic diversity and mating system of wild populations of Keteleeria davidiana var. calcarea in fragmented habitats. To achieve this, we genotyped 46 maternal trees and 214 progenies from four fragmented populations of Keteleeria davidiana var. calcarea using nine pairs of microsatellite primers. The genetic diversity of Keteleeria davidiana var. calcarea (Ho = 0.68, He = 0.63) was lower than that of the species overall but higher than that of other Keteleeria plants. The incidence of unbiased expected heterozygosity (uHe) and allelic richness (Ar) was higher in the maternal generation than in the progeny. This suggests that the genetic diversity of the progeny was lower than that of the maternal generation. Keteleeria davidiana var. calcarea is divided into four populations, but there is significant genetic exchange between the populations according to STRUCTURE and gene flow analyses. The multilocus mating system analysis (MLTR) results indicate that the multilocus outcrossing rate (tm) was 0.902, the single-locus outcrossing rate (ts) was 0.606, the bimaternal inbreeding coefficient (tm-ts) was 0.295, and the coefficient of inbreeding depression(δ) was 0.904. These results suggest a certain degree of selfing and inbreeding in Keteleeria davidiana var. calcarea. To prevent problems associated with inbreeding and conserve the genetic diversity of Keteleeria davidiana var. calcarea, we recommend establishing seed gardens, using artificial pollination, and employing asexual propagation techniques for conservation intervention