Search

• The concept of continuous printing filament hypothesis is proposed through mesoscopic analysis. • A novel progressive failure model is established to predict the intra-layer failure process of FFF 3D printing GFRP. • Mechanical parameters of FFF 3D printing GFRP are determined by designing specific specimens and tests. • The distribution and regularities of intra-layer failure of FFF 3D printing GFRP are explored experimentally. The deficiency of failure analysis methods severely hinders the civil engineering application of Fused Filament Fabrication (FFF) 3D printing composites. In order to comprehensively investigate the failure process, this paper innovatively proposes the concept of continuous printing filament hypothesis based on mesoscopic analysis. This hypothesis serves to characterize the interconnection status between glass fiber reinforced polymer (GFRP) filaments during FFF 3D printing. Building upon this hypothesis, a progressive failure model is established, which can predict the intra-layer failure process under axial quasi-static load accurately. In the failure model, both Mode-2D and Mode-3D failure criteria are employed to pinpoint intra-layer damage initiation, while damage evolution is depicted using a stiffness reduction mode based on the fracture energy criterion. Simultaneously, the fundamental orthotropic mechanical parameters are examined, and 24 variations of printing laminates are meticulously designed. The ultimate tensile strengths (UTS), encompassing both cross-stacking (2/8, 4/6, 5/5) and angle-stacking (30°, 45°, 60°), are tested and simulated using the progressive failure method established during this study. Experimental results show that the lower layers of composites exhibit stronger ultimate resistance due to their layer-by-layer characteristics. Compared to the experimental results, all the relative errors of UTS predicted by Mode-3D are less than 15%. Therefore, the accuracy and predictive capacity of the progressive failure model are affirmed by the experimental data. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of myrislignan (MYR) on the apoptosis of gastric cancer cell line and its relationship with phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway., Methods: The gastric cells (SGC-7901) were treated with MYR at different concentrations, i.e., 0, 25, 50, 100, and 200 μmol/L, for 48 h and 72 h and the effect of MYR on the proliferation of SGC-7901 cells was measured by CCK-8 assay. Then, SGC-7901 cells were treated with different concentrations of MYR at 50, 100, and 200 μmol/L for 48 h. Meanwhile, a normal control group and a dimethyl sulfoxide (DMSO) solvent control group (0.1% DMSO) were established. Flow cytometry was used to determine the apoptosis rate of SGC-7901 cells. The protein expression levels of PI3K, AKT, Bcl-2-associated X protein (BAX), cysteine-dependent aspartate-specifc protease-3 (Caspase-3), and Caspase-9 were determined by Western blot. Then, PI3K activator (20 μmol/mL) was used to treat SGC-7901 cells for 48 h in 4 groups, the control group, 0.1% DMSO group, MYR group, and MYR+PI3K activator group, and the effect on MYR's induction of apoptosis and regulation of the protein expression levels of PI3K, AKT, BAX, Caspase-3, and Caspase-9 in SGC-7901 cells., Results: Compared with the control group, MYR at 50, 100 and 200 μmol/L inhibited the proliferation of gastric cancer cells, increased the apoptosis rate, down-regulated the protein expression levels of PI3K and AKT, and up-regulated the protein expression levels of BAX, Caspase-3, and Caspase-9 in a dose-dependent manner ( P <0.05). However, PI3K activator attenuated MYR-induced apoptosis in gastric cancer cells and MYR's regulation of PI3K, AKT, BAX, Caspase-3, and Caspase-9 protein expression ( P <0.05)., Conclusion: MYR induces the expression of BAX, Caspase-3, and Caspase-9 proteins by inhibiting the PI3K/AKT signaling pathway, thereby promoting the apoptosis of gastric cancer cells., (Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).)

Objective: To investigate the therapeutic effect of artesunate (ART) on influenza A viral pneumonia., Methods: A total of 36 mice were evenly and randomly assigned to six groups, a normal control group (C group), a solvent control group (M group, 10% DMSO), a positive drug group (P group, oseltamivir, 1.25 mg/kg/day), ART high-dose group (ART-G group, 120 mg/kg/day), ART medium-dose group (ART-Z group, 60 mg/kg/day), and ART low-dose group (ART-D group, 30 mg/kg/day). Except for group C, which did not receive any influenza A virus intervention or intraperitoneal injection, mice in the five other groups were infected with influenza A virus through intranasal drip. Then, after 12 hours, mice in the five other groups received intraperitoneal injection of the assigned drugs and dosage once a day. The signs, body weight, and survival of the mice were observed over the course of treatment. After 7 days of treatment, the lung tissue of the mice was collected and weighed, and the lung index was calculated accordingly. HE staining was performed to observe the pathological changes in the lung tissue. The mRNA and protein expression levels of Toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB [p65]), tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and IL-1β were examined with RT-qPCR and Western blot, respectively., Results: Compared with those in C group, mice in the M group had worse physical signs and lower body mass and survival, increased lung index, severe pathological changes in lung tissue, and increased levels of TLR4, NF-κB (p65), TNF-α, IL-6 and IL-1β mRNA and protein expression in their lung tissue ( P <0.05). Compared with those in M group, the mice in the ART groups had better physical signs, higher body mass and survival rate, decreased lung index, improvement of pathological changes in the lung tissue, and decreased levels of level of TLR4, NF-κB (p65), TNF-α, IL-6 and IL-1β mRNA and protein expression in the lung tissue ( P <0.05). Furthermore, the most prominent changes in these indexes were observed in the ART-G group., Conclusion: ART has therapeutic effects on influenza A viral pneumonia, and the mechanisms are related to the inhibition of TLR4/p65 signaling pathway activation and anti-inflammation., (Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).)

Metal-free catalyzed intermolecular tandem Michael addition/cyclization has been developed for the synthesis of benzo[4,5]imidazo[1,2- a ]pyridines from α-bromocinnamaldehyde and 2-substituted benzimidazoles. The reaction promoted by a simple inorganic base displays moderate to good yields and good functional group tolerance. The optical properties of some typical products have been investigated. We found that, due to the presence of the benzene ring at the C1-position of benzo[4,5]imidazo[1,2- a ]pyridines which restricts intramolecular motion, as a new type of aggregation-induced emission (AIE) luminogen (AIEgen), they show very good solid-state fluorescence with quantum yields up to 88.80%. Importantly, the AIE performance of compound 3b can be useful to detect the nitroaromatic explosive picric acid (PA) with a detection limit and quenching constant of 42.5 nM and 7.27 × 10 4 M -M , respectively.

Objective: To prepare the specific monoclonal antibody against the N-terminal specific epitope peptide of anti-mullerian hormone (AMH) and to identify its specificity., Methods: Using bioinformatics analysis software to predict the specific peptide fragment of AMH. Then synthesized four antigenic epitope peptide segments of mature N-terminal region of AMH as the screening target antigen. Synthesized AMH wholegene.Using the prokaryotic expression system to abtain recombinant AMH protein. Immunized BALB/c mice with the recombinant AMH, and prepared mouse spleen cells for fusing with SP/20 cells. Preparation of AMH monoclonal antibody by hybridoma technology. The monoclonal antibodies against AMH were screened by using four N-terminal epitope peptides (1: 439-451 RGRDPRGPGRAQ, 2: 273-285 PPRPSAELEESPP, 3: 42-54 DLDWPPGSPQEPL, 4: 494-506 WPQSDRNPRYGNH) as antigens, and indirect ELISA and Western blot were used to identify the antigen binding characteristics of the selected monoclonal antibodies., Results: Two hybridoma cell lines with stable anti-AMH-1 and anti-AMH-2 antibody activities were screened. The two antibodies were named anti-AMH-1 and anti-AMH-2 respectively. The antibody titers were 1∶12 000 and 1∶1 600 after purification. Western blot confirmed that the two McAbs recognized different antigens. Anti-AMH-1 could not only recognize the N-terminal 439-451 epitope peptide of AMH, but also recognize the amino acid sequence of recombinant AMH, as well as the ovarian tissue. Anti-AMH-2 could recognize recombinant AMH and ovarian tissue., Conclusion: Two monoclonal antibodies against N-terminal specific epitopes of human AMH were successfully constructed., (Copyright© by Editorial Board of Journal of Sichuan University (Medical Science Edition).)

Ojective: To construct the engineering bacteria with recombinant plasmid expressing the multi-epitope vaccine which composed of Helicobacter pylori urea membrane channel protein (UreI), Helicobacter pylori urease B subunit (UreB) and cholera toxin B subunit (CTB), and then to study it's microbiological characteristics., Methods: The sequence contains some dominant epitopes of Helicobacter pylori UreI and UreB was designed, and ctB was added at the N-terminal, all the sequence were linked by flexible linkers. Codon optimization was done according to Escherichia coli (E. coli) BL21 (DE3) bias, the optimized sequence was designated BIB. BIB sequence was synthesized and cloned into plasmid pET28a(+). The recombinant plasmid was confirmed by restriction enzyme digestion and DNA sequencing. The recombinant protein BIB was expressed in E. coli BL21 (DE3) and analyzed by Western blot., Results: The plasmid of pET28a(+)/BIB was constructed successfully, confirmed by restriction enzyme digestion and DNA sequencing. The recombinant protein BIB with relative molecular mass about 33 x 10(3) could be produced by E. coli BL21 (DE3) and was detected by Western blot. The relative molecular mass and N-terminal amino acid sequence of BIB were 100% identity with the design., Conclution: The engineering bacteria with recombinant plasmid expressing the multi-epitope vaccine against Helicobacter pylori was constructed successfully. The recombinant protein BIB can be identified by anti-Sydney strain 1 of Helicobacter pylori (H. pylori SS1) polyclonal antibody and anti-CTB monoclonal antibody, which demonstrated that BIB has the expected antigenicity.

In order to study the feasibility of the identification of Chinese herbal medicines based on terahertz spectroscopy, the optical characteristic of astragalus, angelica, eucommia and three kinds of astragalus samples with different impurities in the frequency range 0.2-2.2 THz were researched by terahertz time-domain spectroscopy (THz-TDS), and their time-domain spectra, the frequency spectra and the absorption spectra were obtained at room temperature. The results indicated that the time-domain spectra, frequency-domain spectra and absorption spectra of astragalus, angelica, and eucommia have large differences in such a frequency range, the frequency-domain spectra and absorption spectra of three kinds of astragalus samples with different impurities are similar but there exists distinct difference. These researches proved that it is feasible to use terahertz time-domain spectroscopy to identify Chinese herbal medicine and provided a new method for Chinese herbal medicine quality control.

Objective: To construct the multi epitope prokaryotic expression plasmid and appropriate engineering bacteria expressing the multi-epitope fusion protein of urea membrane channel protein (UreI), urease B subunit (UreB) and adhesin (HpaA) of Helicobacter pylori, then study its microbiological characteristics., Methods: The target sequence contains multi epitope gene sequence of Helicobacter pylori were designed and synthesized, subsequently; it was subcloned into the expression vector pET28a (+), confirmed by restriction enzyme digestion and DNA sequencing. The fusion protein rIBA was expressed in E. coli Rosseta (DE3) and analyzed by Western blot., Results: The plasmid of pET28a(+)/IBA was constructed successfully, confirmed by endonuclease digestion and sequence analyze. The expressed rIBA protein with relative molecular mass about 40 x 10(3) and can be detected by Western blot., Conclusion: The prokaryotic engineering bacteria expression multi-epitope of the Helicobacter pylori was constructed successfully. The recombinant protein rIBA expressed by the engineering bacteria can be identified by Sydney strain 1 of Helicobacter pylori (H. pylori SS1) specific antibody IgY, which demonstrated that the rIBA has high correlation with H. pylori SS1.

With solvent extraction, a total of four fractions were separated from 75% alcohol extract of Monochoria vaginalis, and their antioxidative activities were measured by iodine method. The results showed that among the fractions, n-butanol fraction exhibited the highest antioxidative activity, which was not only significantly higher than CK (water), but also equivalent to the natural antioxidant tea polyphenols and synthetic antioxidant butylated hydroxyl toluene (BHT). A compound was isolated from the n-butanol fraction by using column chromatography, and identified as stigmasterol 3-O-beta-D-glucopyranoside. Its antioxidative activity estimated by the determination of the percentage of scavenged free radicals indicated that this compound exhibited a higher activity than BHT in scavenging free radicals.