Optimizing Epoxy Interfacial Bonding Properties and Failure Mechanism between Carbon Textile-Reinforced Mortar Composites and Concrete Substrates.

Textile-reinforced mortar (TRM) composites have been extensively utilized in building reinforcement due to their exceptional mechanical properties. The weakest link in the entire structure is the interface between the TRM composites and the concrete; however, it plays a crucial role in effectively transferring stress. Researchers have taken measures to improve the strength of the interface, but the results are relatively scattered. In this paper, the surface treatment of the substrate, the thickness of the surfactant, and the physical doping of the surfactant on the interfacial bonding strength of the concrete were comparatively studied. The results demonstrate that the sandblasting treatment on the surface of the concrete enhances the bonding area between the mortar and the concrete of the reinforcement layer, leading to a 50% increase in the bending resistance of the structure. When the surfactant thickness increases to 0.5 kg/m2, more surfactants penetrate the mortar and concrete. This significantly inhibits the occurrence of cracks in the structure. The addition of 2.5% Al2O3 nanomaterials to the surfactant diminishes the shrinkage rate of the curing process, enhances the impact toughness, and improves the flexural and compressive properties of the bonding layer. The ultimate load of the structure increases by 65%. Physical doping of the surfactant is the most effective measure with the most apparent improvement result. It significantly enhances the bonding strength of the interface and can be widely used in construction.

Interface Bonding Properties and Mechanism of Steel Fiber and Hot Melt Adhesive via Interface Design Engineering.

Steel fiber textile, which is composed of steel fibers and glass fibers, has a support layer impregnated with hot melt adhesive (HMA). During long-term service, the bonding force between the steel fiber/HMA system interfaces is poor. In order to improve the bond strength and durability of the interface, this paper introduced sandblasting, acid-etching, and phosphating treatments on the surface of the steel fibers. Also, the effects of these three pretreatment methods on the bond strength of the steel fiber/HMA interface were investigated. The results indicate that the interfacial bond strength of composites made from steel fibers is improved via surface treatment. Under a hydrothermal and simulated concrete pore solution environment, the durability of the steel fiber/HMA interface after sandblasting and acid-etching pretreatment is not as good as that after phosphating pretreatment. The mechanical properties of the phosphating/HMA composite were maintained at 4.56 and 2.24 times compared to those of the untreated/HMA composite, respectively. This is because the pinning effect formed by the phosphating film on the surface of steel fibers at the interface of steel fiber/HMA can serve as a physical barrier against corrosion, preventing the invasion of chloride ions and water vapor and improving the durability of the interface.

Targeted Elimination of Surface Defects in Carbon Fibers: Formation of a Hybrid Structure Combining Rigidity with Flexibility from Sonochemical-Induced Directional Growth of Nano-ZIF-8 and Subsequent Annealing.

Currently, the mechanical performance of carbon fibers (CFs) has yet to fully realize its theoretical potential. This is predominantly attributed to the significant constraints posed by surface defects, greatly impeding the widespread application of carbon fibers. In order to address this issue, we employed a sonochemical-induced approach in this study to achieve in situ growth of nanoscale zeolitic imidazolate framework-8 (ZIF-8) at the surface defects of carbon fibers. After high-temperature treatment, the structure of ZIF-8 decomposed into ZnO and inorganic carbon, reinforcing the carbon fiber structure from both flexible and rigid aspects. Our research indicates that when the temperature reaches 500 °C, a substantial portion of ZIF-8 undergoes thermal decomposition, giving rise to zinc oxide and inorganic carbon. The flexible inorganic carbon and rigid ZnO form a meshlike structure, which welds to the surface defects of carbon fibers, resulting in strong interactions and contributing to the delay of fiber fracture. Compared to unmodified carbon fibers, the mechanical performance increased by approximately 15.86%. Based on the aforementioned analysis, this method can be considered a direct and effective approach for reinforcing carbon fiber structures, presenting a novel approach for the precise elimination of surface defects on carbon fibers.

A Case of Central Venous Catheter-Related Bacteremia Caused by Enterococcus gallinarum.

A chicken farmer with cirrhosis and renal failure presented with an unusual case of catheter-related bacteremia. Testing with the VITEK® 2 Compact system, MALDI-TOF mass spectrometry, and 16S rDNA sequencing identified the pathogen as E. gallinarum. This case demonstrates the importance of maintaining a high level of contextual awareness in patients exposed to avian species to make an informed diagnosis and provide prompt treatment.

Analysis of Intestinal Short-Chain Fatty Acid Metabolism Profile After Probiotics and GLP-1 Treatment for Type 2 Diabetes Mellitus.

Type 2 diabetes accounts for about 90% of diabetes patients, and the incidence of diabetes is on the rise as people's lifestyles change. Compared with GLP-1 treatment, probiotic treatment can directly regulate homeostasis of the host gut microbe, and thus homeostasis of its metabolites. Currently, the regulatory role of probiotics on intestinal metabolites after treatment of type 2 diabetes mellitus remains unclear. The purpose of this study was to investigate the therapeutic effect of probiotics on type 2 diabetes mellitus and its regulatory effect on short-chain fatty acids, which are metabolites of intestinal microorganisms. I collected feces from 15 patients with diabetes before treatment and 15 patients with type 2 diabetes after treatment with GLP-1 and probiotics. The abundance of short-chain fatty acids in feces was determined by GC-MS. Results Both GLP-1 and probiotics could improve the levels of blood glucose, urine glucose and BMI in patients with type 2 diabetes. After glP-1 treatment, two short-chain fatty acids (butyric acid and valerate acid) in intestine were significantly changed. Propionic acid and isovalerate were significantly changed after probiotic treatment. At the same time, KEGG signal pathway enrichment results showed that probiotics intervention mainly achieved the purpose of treating type 2 diabetes through regulating protein and carbohydrate metabolism. Taken together, our study shows changes in intestinal short-chain fatty acids after probiotics or GLP-1 treatment of type 2 diabetes, which will provide us with new insights into the mechanism of probiotics treatment of type 2 diabetes, as well as potential intervention targets for diabetes treatment.

Exploring the Interfacial Phase and π-π Stacking in Aligned Carbon Nanotube/Polyimide Nanocomposites.

To characterize the interfacial microstructure and interaction at a nanoscale has a significant meaning for the interface improvement of the nanocomposites. In this study, the interfacial microstructure and features of aligned multiwalled carbon nanotube (MWNT) and conjugated polymer polyimide (PI) with three molecular structures were investigated using small-angle X-ray scattering (SAXS), wide-angle x-ray diffraction (WAXD), and fluorescence emission spectroscopy. It was found that aligned MWNT/PI nanocomposites had a nonideal two-phase system with the interfaces belonging to long period stacking ordered structure. Attributed to the π-π stacking effect, MWNT/BTDA-MPD presented the most regular arrangement verified by fractal dimension. By adopting a one-dimension correlation function, each phase dimension in aligned MWNT/PI nanocomposites was calculated and verified by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The π-π stacking was demonstrated to be an important interaction between MWNT and PI via WAXD and fluorescence emission spectroscopy, and it was influenced by the linkage bond between benzene rings in PIs. This work is of significance to reveal the interfacial features between conjugated polymer and carbon nanotubes (CNTs), which is favorable for the interface design of CNT-based high performance nanocomposites.

Propofol activates AMPK to inhibit the growth of HepG2 cells in vitro and hepatocarcinogenesis in xenograft mouse tumor models by inducing autophagy.

BACKGROUND: Hepatocellular carcinoma (HCC) is a fatal malignant tumor with a poor prognosis, and is the third leading cause of cancer-related deaths worldwide. This study aimed to investigate the anti-tumor effect of propofol on the proliferation, apoptosis, and cell cycle of HCC by regulating adenosine monophosphate-activated protein kinase (AMPK) in vivo and in vitro. METHODS: The cell counting Kit-8 (CCK-8) assay was employed to screen the effect of propofol on HepG2 cell viability at various concentrations (0.3, 0.6, 1.2, 2.5, 5, 10, 20, 40, 80 and 160 µM). We selected propofol at concentrations of 5, 10 and 20 µM for subsequent experiments. Flow cytometry was used to examine the apoptosis and cell cycle of HCC. Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) was applied to measure the messenger ribonucleic acid (mRNA) expression levels of proliferating cell nuclear antigen (PCNA) and survivin. Western blotting was applied to measure the protein expression levels of PCNA, survivin, cleaved caspase-3, cleaved caspase-9, p27 (Kip1), and cyclin A. The effects of propofol were evaluated by establishing a xenograft tumor model. RESULTS: After treatment with propofol, the mRNA expression levels of PCNA and survivin were decreased compared with the 0 µM propofol (control) group. The colony formation assay showed that the colony formation rate was obviously down-regulated. Flow cytometry demonstrated that HepG2 cell apoptosis was increased. G0/G1 was enhanced compared with the control group, while G2/M was restrained. The levels of cleaved caspase-3, cleaved caspase-9, p27, phospho-AMP-activated protein kinase α1 (p-AMPKα1), phospho-mammalian target of rapamycin (p-mTOR), and phospho-Unc-51 like autophagy activating kinase 1 (p-ULK1) were notably elevated, while the levels of cyclin A were suppressed. The xenograft tumor volume declined in vivo compared with the HepG2 xenograft group. The expression levels of cell proliferation markers (PCNA) were significantly down-regulated markedly, while the expression levels of cell cycle markers (p27) were notablyup-regulated. Terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining showed that cell apoptosis was increased. The levels of p-AMPKα1 were also up-regulated. CONCLUSIONS: Propofol inhibits the proliferation, apoptosis, and cell cycle of HCC by regulating AMPK in vivo and in vitro.