Strengthening Mechanism of Polyurea to Anti-Penetration Performance of Spherical Cell Porous Aluminum.

A composite structure containing a metallic skeleton and polyurea elastomer interpenetrating phase was fabricated, and its anti-penetration performance for low-velocity large mass fragments was experimentally studied. The protection capacity of three polyurea was compared based on the penetration resistance force measurement. Results show that the polyurea coating layer at the backside improves the performance of the polyurea-filled spherical cell porous aluminum (SCPA) plate due to its backside support effect and phase transition effect, which are accompanied by a large amount of energy absorption. The frontal-side-coated polyurea layer failed to shear and provided a very limited strengthening effect on the penetration resistance of the interpenetrating phase composite panel. The filling polyurea in SCPA increased the damage area and formed a compression cone for the backside coating layer, leading to a significant stress diffusion effect. The anti-penetration performance was synergistically improved by the plug block effect of the interpenetrating phase composite and the backside support effect of the PU coating layer. Compared with SCPA, the initial impact failure strength and the average resistance force of the composite plate were improved by 120-200% and 108-274%, respectively.

Distribution Pattern and Influencing Factors of Heavy Metal Resistance Genes in the Yellow River Sediments of Henan Section.

The transformation of heavy metal resistance genes (MRGs) in the environment has attracted increasing attention in recent years. However, few studies have reported the MRG content in the Yellow River, one of the main irrigation water sources in the North China Plain. In this study, we quantified MRG abundance by a metagenomic approach, and assessed the influence on MRGs of both bioavailable and total heavy metal (HM) content. The results indicate that Cu-resistant genes are the most common genes, and the prevalence of arsM needs more attention. Comamonadaceae is the dominant family in the Yellow River, and the presence of organic pollutants may contribute to the prevalence of Vicinamibacteraceae, Nocardioidaceae, and Flavobacteriacea. The results of the Mantel test and Spearman analysis indicate that both the bioavailable fractions and total content of HMs could have little influence on MRGs. Network analysis results indicate that some dominant bacteria could be the potential hosts of some prevalent MRGs, which may exert an adverse impact on human health.

The role of long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (NEAT1) in chronic periodontitis progression.

Long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) is a novel pro-inflammatory factor in severe human diseases. Since inflammatory plays important roles in periodontitis progression, we aimed to explore the role of NEAT1 in chronic periodontitis (CP) in vitro. We established a periodontitis cell model was established by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS)-induced periodontal ligament cells (PDLCs). Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to detect the expression of NEAT1, microRNA (miR)-200c-3p, and tumor necrosis factor receptor-associated factor 6 (TRAF6). Cell viability, inflammatory factors, and protein expression of Bcl-2, Bax, and TRAF6 were analyzed by MTT, enzyme-linked immunosorbent assay, and Western blot. The target relationships among NEAT1, miR-200c-3p, and TRAF6 were predicted by the StarBase/TargetScan software, and further validated by dual-luciferase reporter assay. In this research, NEAT1 is up-regulated in CP tissues and periodontitis model group. Silencing of NEAT1 and over-expression of miR-200c-3p enhanced cell viability and repressed apoptosis in the periodontitis model group. NEAT1 targets miR-200c-3p, and miR-200c-3p further targets TRAF6. MiR-200c-3p inhibitor or over-expression of TRAF6 reversed the promoting effect of NEAT1 knockdown on cell viability, and the inhibiting effects on inflammatory cytokines and cell apoptosis. Consequently, the silencing of NEAT1 inhibits inflammation and apoptosis via targeting miR-200c-3p/TRAF6 axis, thereby contributing to alleviate the progression of CP. This finding could provide an underlying target for the treatment of CP.

Clinicopathological Features of Programmed Cell Death-ligand 1 Expression in Patients with Oral Squamous Cell Carcinoma.

OBJECTIVE: Programmed cell death-ligand 1 (PD-L1) expression has been shown to play important roles in various types of cancer. However, the role of PD-L1 expression has not been conclusively reported in patients with oral squamous cell carcinoma (OSCC). Accordingly, in this meta-analysis, we investigated the clinicopathological value of PD-L1 expression in patients with OSCC. METHODS: Google Scholar, PubMed, EMBASE, and CNKI databases were searched to find relevant studies published through to September 16, 2019. The relationships between PD-L1 expression in patients with OSCC and clinicopathological features were assessed using risk ratio (RR) and 95% confidence intervals (CIs). RESULTS: Sixteen studies including 1989 participants were included. The results indicated that high PD-L1 expression was correlated with sex (RR = 1.28, 95% CI: 1.16-1.42, P < 0.001), N stage (RR = 1.19, 95% CI: 1.06-1.33, P = 0.003), M stage (RR = 1.64, 95% CI: 1.01-2.66, P = 0.044), low differentiation (RR = 1.16, 95% CI: 1.01-1.33, P = 0.034), and human papilloma virus infection (RR = 1.38, 95% CI: 1.14-1.68, P = 0.001), but unrelated to TNM stage or T stage. There was no significant publication bias in the studies included in this analysis. CONCLUSIONS: This meta-analysis revealed that high PD-L1 expression in patients with OSCC was correlated with clinicopathological features. Further large-scale studies are necessary to confirm our results.

Effects of downregulated expression of microRNA-187 in gastric cancer.

microRNAs (miRNAs) are involved in cancer development and progression, and have regulatory roles as tumor suppressors or oncogenes. Although aberrant expression of miR-187 has been observed in several types of cancer, its pathophysiological role and relevance to tumorigenesis in gastric cancer (GC) remains unknown. In the present study, the expression and biological role of miR-187 was investigated in 32 specimens of GC tissues and their adjacent non-tumorigenic controls, and the association between miR-187 expression and clinical features of GC were analyzed further. Kaplan-Meier survival curves determined the clinical significance of miR-187 expression in GC. Following transfection with miR-187 mimics, the biological functions of miR-187 were determined by cell proliferation and cell cycle assays. Moreover, following transfection with miR-187 mimics, the targets regulated by miR-187 were investigated using western blotting. Luciferase reporter assays confirmed whether miR-187 regulated MAD2 mitotic arrest deficient-like 2 (MAD2L2) and stomatin (EPB72)-like 2 (STOML2) expression. The data of the present study revealed that miR-187 was significantly downregulated in GC compared with adjacent non-tumorigenic counterparts. Furthermore, decreased expression of miR-187 correlated with cell differentiation (P<0.05), TNM staging (P<0.05) and poor prognosis in GC patients. Functional studies indicated that miR-187 overexpression evidently inhibited MGC-803 cell proliferation in vitro and altered the cell cycle by arresting cells in the G0/G1 phase. In addition, the luciferase assay and western blotting revealed that MAD2L2 and STOML2 were targeted by miR-187. In conclusion, it is suggested that miR-187 functions as a tumor suppressor in GC, and is important in the development and progression of GC. Moreover, miR-187 may be a potential biomarker and therapeutic target in GC.

[Application of low intensity ultrasound in the extraction of totally impacted mandibular third molars].

PURPOSE: To observe the clinical effects of low intensity ultrasound in extraction of totally impacted third molars. METHODS: 40 patients with totally impacted third molars on both sides of the mandible verified by X-ray were selected. After extraction of the teeth, the socket on one side was treated with low intensity ultrasound while the other side underwent no treatment. Statistical analysis was performed with SPSS 10.0 on all patients in form of pain, swelling, dry socket and bone healing. RESULTS: In the experimental group, 4 patients complained of severe pain while 16 patients in the control group (P < 0.05). Moderate or severe swelling were not uncommon in both experimental and control groups (P > 0.05); No patients suffered from dry socket in the experimental group and 4 patients suffered from dry socket in the control group (P < 0.05); There were 35 patients with complete bone healing in the experimental group while 21 patients with complete bone healing in the control group (P < 0.01). CONCLUSIONS: The use of low intensity ultrasound in extraction of totally impacted mandibular third molars reduced the severity of post-operative pain and the incidence dry socket, and it also stimulated bone healing, but it showed no effect on relieving post-operative swelling.