Laccase biosensor based on electrospun copper/carbon composite nanofibers for catechol detection.

The study compared the biosensing properties of laccase biosensors based on carbon nanofibers (CNFs) and copper/carbon composite nanofibers (Cu/CNFs). The two kinds of nanofibers were prepared by electrospinning and carbonization under the same conditions. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy were employed to investigate the morphologies and structures of CNFs and Cu/CNFs. The amperometric results indicated that the Cu/CNFs/laccase(Lac)/Nafion/glass carbon electrode (GCE) possessed reliable analytical performance for the detection of catechol. The sensitivity of the Cu/CNFs/Lac/Nafion/GCE reached 33.1 µA/mM, larger than that of CNFs/Lac/Nafion/GCE. Meanwhile, Cu/CNFs/Lac/Nafion/GCE had a wider linear range from 9.95 × 10(-6) to 9.76 × 10(-3) M and a lower detection limit of 1.18 µM than CNFs/Lac/Nafion/GCE. Moreover, it exhibited a good repeatability, reproducibility, selectivity and long-term stability, revealing that electrospun Cu/CNFs have great potential in biosensing.

Effect of CSA concentration on the ammonia sensing properties of CSA-doped PA6/PANI composite nanofibers.

Camphor sulfonic acid (CSA)-doped polyamide 6/polyaniline (PA6/PANI) composite nanofibers were fabricated using in situ polymerization of aniline under different CSA concentrations (0.02, 0.04, 0.06, 0.08 and 0.10 M) with electrospun PA6 nanofibers as templates. The structural, morphological and ammonia sensing properties of the prepared composite nanofibers were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), four-point probe techniques, X-ray diffraction (XRD) and a home-made gas sensing test system. All the results indicated that the CSA concentration had a great influence on the sensing properties of CSA-doped PA6/PANI composite nanofibers. The composite nanofibers doped with 0.02 M CSA showed the best ammonia sensing properties, with a significant sensitivity toward ammonia (NH3) at room temperature, superior to that of the composite nanofibers doped with 0.04-0.10 mol/L CSA. It was found that for high concentrations of CSA, the number of PANI-H+ reacted with NH3 would not make up a high proportion of all PANI-H+ within certain limits. As a result, within a certain range even though higher CSA-doped PA6/PANI nanofibers had better conductivity, their ammonia sensing performance would degrade.

Design of large-bandwidth single-mode operation waveguides in silicon three-dimensional photonic crystals using two guided modes.

We report on the design of silicon three-dimensional (3D) photonic crystal (PC) waveguides with a combination of acceptor-type and donor-type line defects. Tuning the width of the acceptor-type line defect allows the waveguide to support two guided modes, which enable single-mode propagation over 98.7% of the complete photonic bandgap (cPBG). In addition, we demonstrate that the frequency ranges for single-mode propagation can be extended to the entire range of the cPBG by further tuning the thickness of the layers in which the donor-type line defects are located. The wide ranges of available frequencies for single mode propagation enable flexible design of 3D PC components and will provide a route towards future 3D photonic circuits.

Downregulation of CASTOR1 Inhibits Heat-Stress-Induced Apoptosis and Promotes Casein and Lipid Synthesis in Mammary Epithelial Cells.

Heat stress is one of the most important factors limiting the milk yields of dairy animals. This decline can be attributed to the heat-stress-induced apoptosis of mammary epithelial cells (MECs). The cytosolic arginine sensor for mTORC1 subunit 1 (CASTOR1) is a crucial upstream regulator of the mechanistic target of rapamycin complex 1 (mTORC1) signaling, which has close connections with apoptosis. However, the specific roles of CASTOR1 in regulating the apoptosis and lactation of MECs are still obscure. In the present study, we found that heat stress promotes apoptosis and CASTOR1's expression in HC11 cells. Downregulation of CASTOR1 inhibits heat-stress-induced apoptosis through a ROS-independent pathway. In addition, silencing of CASTOR1 promotes cell proliferation, cell cycle progression, and milk component synthesis, and overexpressing of CASTOR1 reverses these observations. Furthermore, we found that silencing of CASTOR1 contributes to the nuclear transport of SREBP1 and promotes lipid synthesis. This study demonstrates the pivotal roles of CASTOR1 in heat-stress-induced apoptosis and milk component synthesis in MECs.

Metabolomics analysis and membrane damage measurement reveal the antibacterial mechanism of lipoic acid against Yersinia enterocolitica.

Yersinia enterocolitica is a pathogenic microorganism that can cause food-borne diseases. Lipoic acid (LA) has been used as an antioxidant against bacteria, but its antibacterial mechanism is rarely reported. This study aims to explore the antibacterial mechanism of LA and its effect on the metabolites of Y. enterocolitica through membrane damage and metabolomics analysis. The results showed that the minimum inhibitory concentration (MIC) of LA against Y. enterocolitica was 2.5 mg mL-1. The membrane potential was depolarized, and intracellular pH (pHin) and ATP were significantly reduced, indicating that LA destroys the cell membrane structure. Confocal laser scanning microscopy (CLSM) and field emission scanning electron microscopy (FESEM) further confirmed LA-induced cell membrane damage. The metabolic profile of Y. enterocolitica following LA treatment was analyzed by liquid chromatography-mass spectrometry (LC-MS). In the metabolome evaluation, 6209 differential metabolites were screened, including 3394 up-regulated and 2815 down-regulated metabolites. Fifteen metabolic pathways of Y. enterocolitica exhibited significant changes after LA treatment, including the pathways important for amino acid and nucleotide metabolism. The results show that LA is a bacteriostatic substance with potential application value in the food industry.

Sex-Specific Differences in the Clinical Profile Among Patients with Tracheobronchial Tuberculosis: A Hospital-Based Cross-Sectional Study in Shenzhen, China.

Purpose: Tracheobronchial tuberculosis (TBTB) has been proposed to occur more commonly in female patients. However, to date, studies that systematically delineate differences between female and male patients with TB infection are lacking. We aimed to comprehensively assess the sex-specific differences in clinical manifestation, bronchoscopy performance, bacteriological examination, and imaging of TBTB in Shenzhen, China. Methods: All patients with diagnosed TBTB from August 1, 2018 to July 31, 2021 at The Third People's Hospital of Shenzhen were enrolled in the present study. Demographic information, clinical manifestations, blood tests, chest computed tomography, and bronchoscopic findings were collected, and assessed their sex-specific differences. Results: Of these 331 patients, 238 patients (71.9%) were female, and 93 patients (28.1%) were male, with an overall average age of 37.3 years. The average age of male patients with TBTB was more than 5 years older than that of female patients. The prevalence of lymph fistula and diabetes mellitus was significantly higher in male patients than female patients (8.6% vs 1.7%, P = 0.005; 17.2% vs 2.1%, P < 0.001). The positive proportion of sputum smear was higher in male patients (27.9%) than in female patients (16.7%, P = 0.026). Moreover, the mean monocyte-to-lymphocyte ratio, serum CRP, and IL-6 levels were significantly higher in male patients than in female patients (P < 0.05). Conclusion: In summary, in patients with TBTB diagnosis, male sex was associated with a high prevalence of diabetes mellitus, lymph fistula, and smear-positive ratio, as well as high inflammation levels. The management of young female and male patients with diabetes mellitus and high inflammation levels should be strengthened. Furthermore, to reduce the burden of TBTB, we must pay attention to the risk of TBTB in past tuberculosis patients, especially male patients under 45 years old and female patients over 45 years old.

Evaluation of gallic acid on membrane damage of Yersinia enterocolitica and its application as a food preservative in pork.

This study was aimed to examine the membrane damage mechanism of gallic acid (GA) on Yersinia enterocolitica BNCC 108930, and to explore whether GA can prolong the shelf life of pork. The minimal inhibitory concentration (MIC) of GA against Y. enterocolitica was determined by adopting the broth microdilution method. Second, an investigation was conducted on the morphological and physiological variations of Y. enterocolitica after the GA treatment. Finally, a response surface approach was used to establish the growth inhibition model of GA against Y. enterocolitica in pork. The MIC of GA against Yersinia enterocolitica BNCC 108930 was 2.5 mg/mL. GA affects the membrane integrity of Y. enterocolitica, as demonstrated by a significant decrease in intracellular ATP and pH. The results showed that the number of Y. enterocolitica in pork meat containing 5 mg/g of GA decreased by 2 logarithmic cycles during storage at 4 °C for 3 days. According to the obtained findings, GA could be used as a food preservative to prolong the shelf life of pork.

The AhR ligand phthiocol and vitamin K analogs as Pseudomonas aeruginosa quorum sensing inhibitors.

The aryl hydrocarbon receptor (AhR) protein senses microbial-secreted metabolites to trigger the host's innate immune system. The Pseudomonas quinolone signal (PQS) and Mycobacterium tuberculosis (MTb) metabolite phthiocol (Pht) are both ligands of AhR with similar chemical structures. As PQS is an essential quorum-sensing molecule that regulates a wide range of virulence factors in Pseudomonas aeruginosa, we hypothesized that Pht and its analogs are potential P. aeruginosa quorum-sensing inhibitors (QSIs) with immune-modulating functions. In this study, we demonstrated that Pht was able to inhibit the P. aeruginosa pqs QS system and reduce both biofilm formation and the production of pyocyanin. Molecular docking analysis suggested that Pht competes with PQS at the binding site of its receptor, PqsR. An electrophoretic mobility shift assay confirmed the Pht-PqsR interaction and showed that Pht attenuated PqsR from binding to the pqsA promoter. Proteomic analysis showed that synthesis of the key pqs QS proteins decreased upon the addition of Pht to the bacterial cultures. Furthermore, Pht analogs vitamins K1 (Phylloquinone), K2 (Menaquinones), and K3 (Menadione) were also showed to inhibit the P. aeruginosa pqs QS system while able to activate the AhR signaling pathways. Our study suggests that the AhR ligands Pht and its vitamin K analogs are promising QSIs for the alternative treatment of P. aeruginosa infections.

Processing and characterization of phosphate glass fiber/polylactic acid commingled yarn composites for commercial production.

This study investigated the production of phosphate glass fiber/polylactic acid (PGF/PLA) commingled yarns, textiles and composites for biomedical applications. The PGF volume contents of the composites investigated were 25% and 40%. Plain weave textiles with yarn counts of 10 warp/cm and 6 weft/cm were produced using a commercial weaving machine. An orthogonal array design (OAD) was employed as a statistical method to investigate the effects of compression molding parameters (processing temperature, preheating time, compression time, and pressure) on flexural strength and porosity of PGF/PLA textile composites. Processing temperature showed the most significant effect in achieving maximum laminate flexural strength and molecular weight of PLA. Processing models were developed using regression techniques to predict the laminate flexural strength and the molecular weight of PLA. Composites with fiber contents of 25 and 40 vol% produced using optimized processing conditions identified by the processing models, provided flexural strengths of 236 MPa and 293 MPa, respectively.

Effects of temperature, oxygen and steam on pore structure characteristics of coconut husk activated carbon powders prepared by one-step rapid pyrolysis activation process.

Activated carbon powders made from coconut husk (CHCs) were prepared by one-step rapid pyrolysis activation process. Effects of temperature, oxygen and steam on the pore structure of CHCs were investigated. Results showed that high temperature, oxygen and steam all motivated the development of the CHCs pore structure. High temperature accelerated the evaporation of volatiles and led to more micropore structures. Oxygen promoted the development of both micropores and mesopores. CHCs' porosity separately presented a linear and a logarithmic growth with the increase of the preparation temperature and oxygen content. CHCs prepared under 1000 â„ƒ with activation agents of 6% oxygen and 20% steam exhibited the largest specific surface area and total pore volume of 415.85 m2/g and 0.1748 cm3/g. Steam can diffuse into the CHC matrix and enhance the formation of more mesopores. Steam over 20% would over-burn the substance and lead to the collapse of some pore structures.

Sonochemical synthesis of ordered SnO2/CMK-3 nanocomposites and their lithium storage properties.

In this study, we successfully prepare SnO(2) nanoparticles inside the pore channels of CMK-3 ordered mesoporous carbon via sonochemical method. The content of SnO(2) is 17 wt % calculated according to the energy-dispersive X-ray spectroscopy (EDS) result. CMK-3 with 17 wt % loading of SnO(2) nanoparticles has a large specific surface area and pore volume. Electrochemical performance demonstrates that the ordered SnO(2)/CMK-3 nanocomposites electrode possesses higher reversible capacity and cycling stability than that of original CMK-3 electrode. Moreover, the ordered SnO(2)/CMK-3 nanocomposites electrode also exhibits high capacity at higher charge/discharge rate. The improved electrochemical performance is attributed to the nanometer-sized SnO(2) formed inside CMK-3 and the large surface area of the mesopores (3.4 nm) in which the SnO(2) nanoparticles are formed.