基于p–y曲线法分析隧道开挖条件下邻近桩基的水平反应

在分析隧道开挖条件下邻近桩基的水平反应时,基于考虑桩土界面非线性的p–y曲线,引入统一极限桩土相互作用力的概念,利用有限差分方法通过迭代求解给出隧道开挖与邻近单桩相互作用的弹塑性解答。在群桩计算中引入考虑群桩效应的p–因子(fm),从而得到群桩中各单桩的p–y曲线,进而通过有限差分方法求得考虑轴力情况下群桩中各单桩的变形、转角、弯矩和剪力。同时通过已有试验和实测数据对本文方法进行验证分析,结果表明:本文方法与试验与实测结果得到了较好的一致性;分析隧道开挖条件下邻近桩基的水平反应时,群桩中的第一排桩与同位置处的单桩性质相似,后排桩由于群桩效应的存在受到的影响将明显小于前排桩。

Dibenzocyclooctadiene Lignans with Platelet-Activating Factor (PAF) Antagonist Activity from Kadsura heteroclita

Seven known dibenzocyclooctadiene lignans,tigloylgomisin P(1), angeloylgomisin P(2),gomisin A(3),Schizandrin(4),angeloylgomisin H(5),gomisin B(6) and R(+)-gomisin M_1(7)were isolated from Kadsura heteroclita.The conformation of tiglolylgomisin P(1)was established by 2D NMR techniques.Using[~3H]platelet activating factor(PAF)binding to human platelet membrane assay,(1),(2)and(7)showed PAF receptor antagonistic activities.

An Intelligent Early Warning Method of Press-Assembly Quality Based on Outlier Data Detection and Linear Regression

Focusing on controlling the press-assembly quality of high-precision servo mechanism,an intelligent early warning method based on outlier data detection and linear regression is proposed.Linear regression is used to deal with the relationship between assembly quality and press-assembly process,then the mathematical model of displacement-force in press-assembly process is established and a qualified press-assembly force range is defined for assembly quality control.To preprocess the raw dataset of displacement-force in the press-assembly process,an improved local outlier factor based on area density and P weight(LAOPW)is designed to eliminate the outliers which will result in inaccuracy of the mathematical model.A weighted distance based on information entropy is used to measure distance,and the reachable distance is replaced with P weight.Experiments show that the detection efficiency of the algorithm is improved by 5.6 ms compared with the traditional local outlier factor(LOF)algorithm,and the detection accuracy is improved by about 2%compared with the local outlier factor based on area density(LAOF)algorithm.The application of LAOPW algorithm and the linear regression model shows that it can effectively carry out intelligent early warning of press-assembly quality of high precision servo mechanism.

Astragalus polysaccharides can regulate cytokine and P-glycoprotein expression in H22 tumor-bearing mice

AIM:To investigate the adjunct anticancer effect of Astragalus polysaccharides in H22 tumor-bearing mice.METHODS:To establish a solid tumor model,5.0 × 10 6 /mL H22 hepatoma cells were inoculated subcutaneously into the right armpit region of Kunming mice(6-12 wk old,18-22 g).When the tumors reached a size of 100 mm 3,the animals were treated as indicated,and the mice were randomly assigned to seven groups(n = 10 each).After ten days of treatment,blood samples were collected from mouse eyes,and serum was harvested by centrifugation.Mice were sacrificed,and the whole body,tumor,spleen and thymus were weighed immediately.The rate of tumor inhibition and organ indexes were calculated.The expression levels of serum cytokines,P-glycoprotein(P-GP) and multidrug resistance(MDR) 1 mRNA in tumor tissues were detected using enzyme-linked immunosorbent assay,Western blotting,and quantitative myeloid-derived suppressor cells reverse transcription-polymerase chain reaction,respectively.RESULTS:The tumor inhibition rates in the treatment groups of Adriamycin(ADM) + Astragalus polysaccharides(APS)(50 mg/kg),ADM + APS(100 mg/kg),and ADM + APS(200 mg/kg) were significantly higher than in the ADM group(72.88% vs 60.36%,P = 0.013;73.40% vs 60.36%,P = 0.010;77.57% vs 60.36%,P = 0.001).The spleen indexes of the above groups were also significantly higher than in the ADM group(0.65 ± 0.22 vs 0.39 ± 0.17,P = 0.023;0.62 ± 0.34 vs 0.39 ± 0.17,P = 0.022;0.67 ± 0.20 vs 0.39 ± 0.17,P = 0.012),and the thymus indexes of the ADM + APS(100 mg/kg) and ADM + APS(200 mg/kg) groups were significantly higher than in the ADM group(0.20 ± 0.06 vs 0.13 ± 0.04,P = 0.029;0.47 ± 0.12 vs 0.13 ± 0.04,P = 0.000).APS was found to exert a synergistic antitumor effect with ADM and to alleviate the decrease in the sizes of the spleen and thymus induced by AMD.The expression of interleukin-1α(IL-1α),IL-2,IL-6,and tumor necrosis factor-α(TNF-α) was significantly higher in the ADM + APS(50 mg/kg),ADM + APS(100 mg/kg) and ADM + APS(200 mg/kg) groups than in the ADM group;and IL-10 was significantly lower in the above groups than in the ADM group.APS could increase IL-1α,IL-2,IL-6,and TNF-α expression and decrease IL-10 levels.Compared with the ADM group,APS treatment at a dose of 50-200 mg/kg could downregulate MDR1 mRNA expression in a dose-dependent manner(0.48 ± 0.13 vs 4.26 ± 1.51,P = 0.000;0.36 ± 0.03 vs 4.26 ± 1.51,P = 0.000;0.21 ± 0.04 vs 4.26 ± 1.51,P = 0.000).The expression level of P-GP was significantly lower in the ADM + APS(200 mg/kg) group than in the ADM group(137.35 ± 9.20 mg/kg vs 282.19 ± 20.54 mg/kg,P = 0.023).CONCLUSION:APS exerts a synergistic anti-tumor effect with ADM in H22 tumor-bearing mice.This may be related to its ability to enhance the expression of IL1α,IL-2,IL-6,and TNF-α,decrease IL-10,and downregulate MDR1 mRNA and P-GP expression levels.

Ten1p promotes the telomeric DNA-binding activity of Cdc13p： implication for its function in telomere length regulation

In Saccharomyces cerevisiae, the essential gene CDC13 encodes a telomeric single-stranded DNA-binding protein that interacts with Stnlp and Tenlp genetically and physically, and is required for telomere end protection and telomere length control. The molecular mechanism by which Tenl participates in telomere length regulation and chromosome end protection remains elusive. In this work, we observed a weak interaction of Cdc13p and Tenlp in a gelfiltration analysis using purified recombinant Cdc13p and Tenlp. Tenlp itself exhibits a weak DNA-binding activity, but enhances the telomeric TG1-3 DNA-binding ability of Cdc13p. Cdc13p is communoprecipitated with Tenlp. In the mutant ten1-55 or ten1-66 cells, the impaired interaction between Tenlp and Cdc13p results in much longer telomeres, as well as a decreased association of Cdc13p with telomeric DNA. Consistently, the Ten1-55 and Ten1-66 mutant proteins fail to stimulate the telomeric DNA-binding activity of Cdc13p in vitro. These results suggest that Tenlp enhances the telomeric DNA-binding activity of Cdc13p to negatively regulate telomere length.

Regulatory effects of insulin-like growth factor-1 on the expression of sensory neuropeptide mRNAs in cultured dorsal root ganglion neurons with excitotoxicity induced by glutamate

Objective To determine the effects of insulin-like growth factor-1 （IGF-1） on the expression of preprotachykinin （PPT） mRNA encoding substance P （SP） and calcitonin gene-related peptide （CGRP） mRNA in cultured dorsal root ganglion （DRG） neurons with excitotoxicity induced by glutamate （Glu）. Methods DRGs were dissected from embryonic day 15 Wistar rats. DRG neurons were dissociated and cultured for 48 h and then exposed to Glu （0.2 mmol/L） or Glu （0.2 mmol/L） plus IGF- 1 （5 nmol/L, 10 nmol/L and 20 nmol/L） for 12 h. The DRG neurons in control group were exposed to only growth media throughout the experiment. After that, the living DRG neurons were observed under inverted phase contrast microscope and microphotographs were taken. The expression levels of PPT and CGRP mRNAs were detected by reverse transcriptionpolymerase chain reaction （RT-PCR）. Results IGF-1 could inhibit Glu-induced shortening of neurite. Besides, IGF-1 could significantly increase the levels ofPPT mRNA and CGRP mRNA in primary cultured DRG neurons with Glu-induced excitotoxicity, in a dose-dependent manner. Conclusion IGF-1 may exert neuroprotective effects on DRG neurons against Glu-induced excitotoxicity, probably through regulating the expression levels of PPT and CGRP mRNAs.

Effect of substance P on gene expression of transforming growth factor β-1 and its receptors in rat's fibroblasts

Objective: To investigate the effect of substance P (SP) on gene expression of transforming growth factor β-1 (TGFβ-1), transforming growth factor receptor-1 (TGFR-1) and transforming growth factor receptor-2 (TGFR-2) in fibroblasts cultured in vitro from rat’s granulation tissues. Methods: The fibroblasts from the granulation tissues in the skeletal muscle of rat’s hind limbs injured by formaldehyde were cultured in vitro. When different concentrations (10 -9-10 -5 mol/L) of SP were added into the culture medium, the changes of gene expression of TGFβ-1, TGFR-1 and TGFR-2 in the cultured fibroblasts were observed with reverse transcription polymerase chain reaction at different intervals (0, 3, 6, 12 and 24 hours after incubation). Results: The gene expression of TGFβ-1, TGFR-1 and TGFR-2 in the fibroblasts cultured from rat’s granulation tissues was up-regulated by SP. The peak level of the mRNA expression was found at 10 -8 mol/L SP and the up-regulation effect was not found at 10 -5 mol/L and 10 -6 mol/L. The peak levels of gene expression of TGFβ-1, TGFR-1 and TGFR-2 in the fibroblasts treated with SP were achieved at 6 and 12 hours, respectively. Conclusions: SP has up-regulation effect on the gene expression of TGFβ-1, TGFR-1 and TGFR-2 in fibroblasts from rat’s granulation tissues in vitro, and the effect is related to different stimulating concentrations of SP. It may be concerned with proliferation and differentiation of fibroblasts and formation of scar tissues during wound healing.

Use of cationic microbubbles targeted to P-selectin to improve ultrasound-mediated gene transfection of hVEGF_(165) to the ischemic myocardium

Gene therapies have been applied to the treatment of cardiovascular disease, but their use is limited by the need to deliver them to the right target. We have employed targeted contrast ultrasound-mediated gene transfection （TCUMGT） via ultrasound-targeted microbubble destruction （UTMD） to transfer therapeutic genes to specific anatomic and pathological targets. Phospholipid microbubbles （MBs） with pcDNA3.l-human vascular endothelial growth factor 165 （pcDNA3.I-hVEGFls5） plasmids targeted to P-selectin （MB＋P＋VEGFp） were created by conjugating monoclonal antibodies against P-selectin to the lipid shell. These microbubbles were divided into four groups： microbubble only （MB）, microbubble＋P-selectin （MB＋P）, microbubble＋pcDNA3.l-hVEGF185 plasmid （MB＋VEGFp）, and microbubbie＋ P-selectin＋pcDNA3.1-hVEGF185 piasmid （MB＋P＋VEGFp）. The reverse transcription polymerase chain reaction （RT-PCR） and enzyme-linked immunosorbent assay （ELISA） results showed that the VEGF gene was successfully transfected by TCUMGT and the efficiency is increased with P-selectin targeting moiety. UTMD-mediated delivery of VEGF increased myocardial vascular density and improved cardiac function, and MB＋P＋VEGFp delivery showed greater improvement than MB＋VEGFp. This study drew support from TCUGMT technology and took advantage of targeted ultrasound contrast agent to identify ischemic myocardium, release pcDNA3.1-hVEGF165 recombinant plasmid, and improve the myocardial microenvironment, so promoting the restoration of myocardial function.