Dynamic stabilization of ablative Rayleigh-Taylor instability in the presence of a temporally modulated laser pulse.

This paper presents a numeric study of the dynamic stabilization of the ablative Rayleigh-Taylor instability (ARTI) in the presence of a temporally modulated laser pulse. The results show that the specially modulated laser produces a dynamically stabilized configuration near the ablation front. The physical features of the relevant laser-driven parameters in the unperturbed ablative flows have been analyzed to reveal the inherent stability mechanism underlying the dynamically stabilized configuration. A single-mode ARTI for the modulated laser pulse is first compared with that of the unmodulated laser pulse. The results show that the modulated laser stabilizes the surface perturbations and reduces the linear growth rate and enhancement of the cutoff wavelength. For multimode perturbations, the dynamic stabilization effect of the modulated laser pulse contributes to suppress the small-scale structure and reduce the width of the mixing layer. Moreover, the results show that the stabilization effect of the modulated laser pulse decreases as the maximum wavelength increases.

Multiple eigenmodes of the Rayleigh-Taylor instability observed for a fluid interface with smoothly varying density.

In this article, multiple eigen-systems including linear growth rates and eigen-functions have been discovered for the Rayleigh-Taylor instability (RTI) by numerically solving the Sturm-Liouville eigen-value problem in the case of two-dimensional plane geometry. The system called the first mode has the maximal linear growth rate and is just extensively studied in literature. Higher modes have smaller eigen-values, but possess multi-peak eigen-functions which bring on multiple pairs of vortices in the vorticity field. A general fitting expression for the first four eigen-modes is presented. Direct numerical simulations show that high modes lead to appearances of multi-layered spike-bubble pairs, and lots of secondary spikes and bubbles are also generated due to the interactions between internal spikes and bubbles. The present work has potential applications in many research and engineering areas, e.g., in reducing the RTI growth during capsule implosions in inertial confinement fusion.

[The sodium salicylate affects the expression of NMDA receptor and GABAa receptor subunits in spiral ganglion neurons of the cochlea through DA receptor].

Objective:To investigate mRNA expression of dopamine receptor subtypes in the rat cochlear spiral ganglion neurons (SGN) following exposure to the sodium salicylate. In addition, we observed the effect of sodium salicylate on N methyl-D-aspartic acid (NMDA) receptor subunit NR1 and gamma aminobutyric acid (GABA)a receptor subunit GABRα2 mRNA under the circumstance of DR activation or blocking. Moreover, we also focused on the the interaction between receptors mediated by SS.Method:Immunofluorescence techniques were applied to detect DR (DR1 and DR2) expression in cultured rat SGN. Moreover, RT-PCR was performed to assess NR1 and GABRα2 subunit mRNA.Result:Immunofluorescence images showed co-localization of DR1/DR2 and ßⅢ-tubulin protein in SGN bodies and axons. RT-PCR results illustrated that ①DR subtypes of DRd1-5 were detected in the SGN. ②The mRNA expression of all subtypes of DR and GABRα2, NR1 subunits were obviously upregulated except DRd3 after treatment with sodium salicylate. Among them, DRd1 expression increased 34.64%(t=-5.123,P=0.007),DRd2 expression increased 34.60%(t=-5.206,P=0.006),DRd4 expression increased 20.87%(t=-3.337,P=0.029),DRd5 expression increased 26.42%(t=-6.054,P=0.004),GABRα2 expression increased 30.41%(t=-2.839,P=0.047),NR1 expression increased 39.22%(t=-6.243,P=0.003).③After exposure to sodium salicylate (5 mmol/L), dopamine (100 µmol/L), DR1 agonist (SKF38393,20 µmol/L), DR2 agonist (Quinpirole,20 µmol/L), GABRα2 expression increased 21.78%,27.45%,33.02%,33.42% respectively (F=12.399,P=0.001),and NR1 expression increased 28.70%,26.82%,29.03%,35.05%(F=50.395,P=0.000) respectively.④Compared with the group of sodium salicylate treatment alone, both sodium salicylate + DR1 antagonist (SCH23390,20 µmol/L) group and sodium salicylate + DR2 antagonists (Eticlopride,20 µmol/L) group had a suppression on GABRα2 and NR1 mRNA expression.GABRα2 mRNA reduced 29.56%,37.10%(F=22.101,P=0.000) and NR1 mRNA expression decreased 37.62%,32.83% respectively(F=72.933,P=0.000).Conclusion:Most of the DR subtypes mRNA expression in SGN were increased following exposure to sodium salicylate. DR may be involved in the effect of sodium salicylate on GABAaR and NMDAR mRNA expression.

[Correlative study between X-ray type after healing of congenital pseudarthrosis of the tibia in children and postoperative refracture].

Objective: To investigate the relationship between postoperative X-ray type in 2 years after healing of congenital pseudarthrosis of the tibia(CPT) and refracture of CPT in children. Methods: A retrospective study was performed on 67 children patients with Crawford type Ⅳ CPT who were treated with combined surgeries from December 2007 to August 2012.There were 46 male and 21 female patients with 37 cases with left CPT and 30 cases with right CPT. There were 12 cases with proximal tibia dysplasia, 56 cases with neurofibromatosis type 1. The median age when operation was 2.8 years(from 0.6 to 11.2 years). The patients were divided into three groups, CPT with hypertrophic group, CPT with mediate group and CPT with atrophic group, on the basis of ratio of healing cross-sectional area and transition zone in pseudarthrosis.The incidence of refracture in the three groups were investigated. Results: The refracture rates of three groups were 13%(5/38), 14%(3/21), 5/8, respectively.The refracture rate difference between CPT with hypertrophic group and CPT with mediate group was not statistically significant(P=0.590). The refracture rate of CPT with atrophic group was statistically significant lower than that of CPT with hypertrophic group and CPT with mediate group(P=0.007, 0.019). In addition, the refracture-free cumulative survival rate of CPT with hypertrophic group or CPT with mediate group was higher than that of CPT with atrophic group with the statistically significant difference(both P<0.05). And the refracture-free cumulative survival rate in CPT with hypertrophic group was lower than that in CPT with mediate group, the difference was not significant(P>0.05). Conclusion: After the union of CPT, patients with hypertrophic, mediate type X ray characteristic showed lower incidence of refracture than those with atrophic type.

[Expression of annexin A7 and its clinical significance in gastric carcinoma].

OBJECTIVE: To investigate the expression of annexin A7 (ANXA7) in the differentiation and lymphatic metastasis of gastric cancer (GC), and to investigate the relationship between ANXA7 and biological characteristics of GC. METHODS: The clinicopathological data of 124 patients with gastric cancer who underwent surgical treatment in our hospital were retrospectively reviewed and analyzed. Immunohistochemical staining and Western blot were performed to analyze the expression of ANXA 7 in primary GC tissues. Logistic regression analysis was conducted to evaluate the association between ANXA7 expression level and differentiation of the GC. RESULTS: A total of 124 GC patients were enrolled in this study, and the expression rate of ANXA7 was 65.3% in the GC. The survival rate of ANXA7-positive patients was significantly lower than that in the patients with negative expression (P<0.001). The results of Cox regression analysis showed that the positive expression of ANXA7, submucosal confinement and pathological stage of GC were associated with poor clinical outcomes. The ratio of pixel density value of primary GC tissues with lymph node metastasis was significantly higher than those in the tissues without lymph node metastasis (0.51±0.07 vs. 0.39±0.06, P<0.001). ROC analysis showed a high area under the curve for the ratio of pixel density value of annexin A7 in the primary GC tissues. At a cut-off level of >0.419, the ratio of pixel density value of ANXA7 exhibited a sensitivity of 91.2% and a specificity of 72.7% for detecting lymph node metastasis of GC. CONCLUSION: High annexin A7 expression is associated with poor differentiation of gastric cancer, and it may become a predictor for lymphatic metastasis of GC.

Nonlinear Rayleigh-Taylor instability of rotating inviscid fluids.

It is demonstrated theoretically that the nonlinear stage of the Rayleigh-Taylor instability can be retarded at arbitrary Atwood numbers in a rotating system with the axis of rotation normal to the acceleration of the interface between two uniform inviscid fluids. The Coriolis force provides an effective restoring force on the perturbed interface, and the uniform rotation will always decrease the nonlinear saturation amplitude of the interface at any disturbance wavelength.

[Effects of 6,7-dimethoxycoumarin on experimental arrhythmia].

By using the arrhythmic animal models, the effect of 6,7-dimethoxycoumarin (DMOC) on arrhythmia was investigated. The arrhythmia in anaesthetized rat were induced by iv aconitine 20 micrograms.kg-1 or CaCl2 5 mg.kg-1. The arrhythmia in anesthetized guinea pigs was induced by iv ouabain 3.6 micrograms.kg-1.min-1. Procainamide (PA) was used as a positive control. DMOC (33-500 mg.kg-1, ig) and PA (100-800 mg.kg-1, ig) in anaesthetized rats could delay the time of onset of arrhythmia induced by aconitine. The ED50 of DMOC and PA for postponing the occurrence of ventricular extrasystole (VE) were 88 mg.kg-1 (95% confidence interval was 43-165 mg.kg-1) and 183 mg.kg-1 (95% confidence interval was 109-304 mg.kg-1), respectively. The results suggested that the anti-arrhythmia potency of DMOC was higher than that of PA (P < 0.01).

[Mechanism of treating rheumatoid arthritis with polyglycosides of Tripterygium wilfordii Hook (T II). III. Study on inhibitory effect of T II on in vitro Ig secreted by peripheral blood mononuclear cells from normal controls and RA patients].

The in vitro effects of polyglycosides of Tripterygium wilfordii Hook (T II) on immunoglobulin (Ig) production by peripheral blood mononuclear cells (PB-MC) from seventeen healthy persons and eight rheumatoid arthritis (RA) patients were studied. PBMCs, monocytes and lymphocytes were treated separately with different doses of T II for different periods of time. Cells in different combinations were cultured for two weeks under pokeweed mitogen (PWM) stimulation and the IgG and IgM content of culture supernatants were determined using the double antibody solid-phase immunoradiometric assay. There was no difference in the inhibitory effect of T II on in vitro IgM and IgG production by PB-MCs either between the two types of Ig or between healthy individuals and RA patients. T II acts both on monocytes and lymphocytes, but more strongly on the latter. This observation appears to differ from the reported actions of gold and penicillamine. The results obtained in this study correlate well with those of clinical trials, suggesting that the therapeutic effect of T II is associated with its immunosuppressive activity.