Generation of attosecond gigawatt soft x-ray pulses through coherent Thomson backscattering.

Collision between relativistic electron sheets and counterpropagating laser pulses is recognized as a promising way to produce intense attosecond x rays through coherent Thomson backscattering (TBS). In a double-layer scheme, the electrons in an ultrathin solid foil are first pushed out by an intense laser driver and then interact with the laser reflected off a second foil to form a high-density relativistic electron sheet with vanishing transverse momentum. However, the repulsion between these concentrated electrons can increase the thickness of the layer, reducing both its density and subsequently the coherent TBS. Here, we present a systematic study on the evolution of the flying electron layer and find that its resulting thickness is determined by the interplay between the intrinsic space-charge expansion and the velocity compression induced by the drive laser. How the laser driver, the target areal density, the reflector, and the collision laser intensity affect the properties of the produced x rays is explored. Multidimensional particle-in-cell simulations indicate that employing this scheme in the nonlinear regime has the potential to stably produce soft x rays with several gigawatt peak power in hundreds of terawatt ultrafast laser facilities. The pulse duration can be tuned to tens of attoseconds. This compact and intense attosecond x-ray source may have broad applications in attosecond science.

Optimization of magnetic coupling mechanism of dynamic wireless power transfer based on NSGA-II algorithm.

Optimization of magnetic coupling mechanism is an important way to improve the performance of a dynamic wireless power transfer system. Inspired by the common radial magnetic core for circular coils, a new radial magnetic core for rectangular coils is adopt. Through simulation and experimental results comparison, which has higher coupling coefficient with the same core area. Combined with the magnetic circuit analysis, the magnetic flux leakage and conduction regions are divided into magnetic fluxes with different shapes, which magnetic resistances are calculated respectively. Based on the simulation results, parameter distributions of fluxes under different conditions are obtained. Therefore, the expressions of the coupling coefficient k of the adopt magnetic cores and coils and the design parameters of coils and cores are obtained. Taking the maximum k and the minimum rate of change of coupling coefficient with 100 mm displacement as the optimization objectives, a multi-objective optimization solution is carried out by using NSGA-II algorithm. The coil optimization scheme is obtained and verified by experiments. k and Δk are 0.442 and 6.8% respectively, and the errors are less than 5%. In the optimization process, there is no simulation model constructed. The optimization modeling combined of magnetic field segmentation method and parameter fitting has lower complexity and calculation time of optimization.

Optimization of the Fermentative Production of Rhizomucor miehei Lipase in Aspergillus oryzae by Controlling Morphology.

Morphology plays an important role in the fermentation bioprocess of filamentous fungi. In this study, we investigated the controlling strategies of morphology that improved the efficiency of Rhizomucor miehei lipase (RML) production using a high-yield Aspergillus oryzae. First, the inoculated spore concentrations were optimized in seed culture, and the RML activity increased by 43.4% with the well-controlled mycelium pellets in both ideal sizes and concentrations. Then, the initial nitrogen source and agitation strategies were optimized to regulate the morphology of Aspergillus oryzae in a 5 L bioreactor, and the established stable fermentation system increased the RML activity to 232.0 U/mL, combined with an increase in total RML activity from 98,080 U to 487,179 U. Furthermore, the optimized fermentation strategy was verified by a high-yield Aspergillus oryzae and achieved an additional improvement of RML activity, up to 320.0 U/mL. Moreover, this optimized fermentation bioprocess was successfully scaled up to a 50 L bioreactor, and the RML activity reached 550.0 U/mL. This work has established a stable precision fermentation bioprocess for RML production by A. oryzae in bioreactors, and the controlling strategy developed in this study could potentially be extended to an industrial scale for RML production with high efficiency.

Knockdown of lncRNA PVT1 inhibits retinoblastoma progression by sponging miR-488-3p.

Emerging evidence suggests that long non-coding RNAs (lncRNAs) play a regulatory role in the pathogenesis and progression of retinoblastoma (RB). lncRNA plasmacytoma variant translocation 1 (PVT1) is highly expressed in a plenty of tumors, and is believed to serve as an oncogene. However, the expression, roles, and action mechanisms of PVT1 in the carcinogenesis and progression of RB are still largely unknown. In this study, we found that PVT1 was upregulated in RB tissues and cell lines. PVT1 levels correlated with optic nerve invasion, and intraocular international retinoblastoma classify (IIRC) stage. In addition, the results demonstrated that patients with RB who showed higher expression of PVT1 had worse overall survivals. In WERI-Rb1 and Y79 cells, PVT1 silencing significantly inhibited cell proliferation, migration, invasion, and cell cycle progression and induced cell apoptosis in vitro. Moreover, in vivo xenograft assay indicated that PVT1 knockdown suppressed the tumor volume and tumor weight. The analysis of the mechanisms of action revealed that the reduction of PVT1 inhibited the expression of notch2 by upregulating miR-488-3p. In general, our results demonstrated that PVT1 may be a novel biomarker for prognosis and a new target for the treatment of RB.

Long Noncoding RNA GAS5 Suppresses Tumorigenesis by Inhibiting miR-23a Expression in Non-Small Cell Lung Cancer.

Previous studies reported that elevated expression of long noncoding RNA (lncRNA) GAS5 led to the arrest of non-small cell lung cancer (NSCLC) cell growth and a promotion of apoptosis both in vitro and in vivo. However, its underlying molecular mechanism in NSCLC is still unclear. In the present study, we noted that GAS5 was downregulated in NSCLC tissues and cells and was negatively correlated with miR-23a expression. Luciferase reporter assay and qRT-PCR analysis demonstrated that GAS5 directly interacted with miR-23a and reversely regulated its expression. miR-23a overexpression markedly promoted NSCLC cell proliferation and invasion, while GAS5 overexpression dramatically inhibited NSCLC cell proliferation and invasion and promoted apoptosis. Functional analysis indicated that miR-23a overexpression significantly abolished GAS5 overexpression-induced inhibition of proliferation and invasion, as well as promotion of apoptosis in NSCLC cells. Moreover, xenograft experiments further revealed that upregulation of GAS5 notably impaired the growth of transplanted tumors by suppressing miR-23a in nude mice. These results suggested that overexpression of lncRNA GAS5 inhibits tumorigenesis of NSCLC by inhibiting miR-23a in vitro and in vivo, providing a potential therapeutic strategy for patients with NSCLC.

MiR-27a-3p promotes esophageal cancer cell proliferation via F-box and WD repeat domain-containing 7 (FBXW7) suppression.

Emerging evidence has suggested that dysregulation of microRNA-27a-3p (miR-27a-3p) may contribute to tumor development and progression in various types of cancers. However, its role in esophageal cancer is still unknown. In the present study, miR-27a-3p was significantly increased in esophageal squamous cell carcinoma (ESCC) tissues and cell lines. In esophageal cancer Eca109 cells, ectopic overexpression of miR-27a-3p promoted cell proliferation, meanwhile, cell proliferation was reduced by miR-27a-3p inhibition. Further studies showed that down-regulated miR-27a-3p expression could induced cell cycle arrest at the G1/S transition. In exploring mechanisms underlying the promotive role, our results revealed that miR-27a-3p markedly inhibited the expression of F-box and WD repeat domain-containing 7 (FBXW7). FBXW7, a tumor suppressor, exhibited significantly inhibitory effect on Eca109 cell proliferation. Thus our observations suggested that miR-27a-3p functioned as a tumor suppressor by targeting FBXW7. These findings indicated that miR-27a-3p could be considered as a potential therapeutic strategy for ESCC therapy.

Protective effect of resveratrol on lens epithelial cell apoptosis in diabetic cataract rat.

OBJECTIVE: To study the protective effect of resveratrol on lens epithelial cell apoptosis in diabetic cataract rat. METHODS: A total of 84 Wistar rats were divided into 4 groups: 12 in Group A (control group), 24 in Group B (diabetic cataract group), 24 in Group C (therapeutic-dose of resveratrol group) and 24 in Group D (low-dose of resveratrol group). Rats in Group B-D were given with 60 mg/kg streptozotocin through intraperitoneal injection. Rats in Group C were given with 100 mg/kg resveratrol and rats in Group D were given with 20 mg/kg resveratrol. The caspase-3 expression levels and apoptosis ratios of LEC among each group were observed; the degrees of lens opacity in Group B-D after 12 weeks were compared. RESULTS: There were significant differences in caspase-3 expression levels, apoptosis ratios of LEC among groups at 4 w, 8 w and 12 w (P<0.05). After 12 weeks, in Group B the degree of lens opacity was as follow: 0 (0.00%) in grade I, 3 (37.50%) in grade II, 2 (25.00%)in grade III, 2 (25.00%)grade IV, and 1 (12.50%) in grade V; in Group C: 2 (25.00%)in grade I, 4 (50.00%) in grade II, 2 (25.00%)in grade III, 0 (0.00%)grade IV, and 0 (0.00 %) in grade V; in Group D: 1 (12.50%)in grade I, 4 (50.00%) in grade II, 2 (25.00%) in grade III, 1 (12.50%) grade IV, and 0 (0.00%) in grade V. The difference among Group B-D was statistically significant (P<0.05). CONCLUSIONS: Resveratrol has protective effect on lens epithelial cell apoptosis in diabetic cataract rat, and the effect is relative to its dose.