Modular supersonic nozzle for the stable laser-driven electron acceleration.

The sharp density down-ramp injection (shock injection) mechanism produces the quasi-monoenergetic electron beam with a bunch duration of tens of femtoseconds via laser wakefield acceleration. The stability of the accelerated electron beam strongly depends on the stability of the laser beam and the shock structure produced by the supersonic gas nozzle. In this paper, we report the study of a newly designed modular supersonic nozzle with a flexible stilling chamber and a converging-diverging structure. The performance of the nozzle is studied both numerically and experimentally with the computational fluid dynamics simulation and the Mach-Zehnder interferometry method. The simulation results and the experimental measurements are well consistent, and both prove the effectiveness of the stilling chamber in stabilizing the gas flow.

Magnetic field amplification driven by the gyro motion of charged particles.

Spontaneous magnetic field generation plays important role in laser-plasma interactions. Strong quasi-static magnetic fields affect the thermal conductivity and the plasma dynamics, particularly in the case of ultra intense laser where the magnetic part of Lorentz force becomes as significant as the electric part. Kinetic simulations of giga-gauss magnetic field amplification via a laser irradiated microtube structure reveal the dynamics of charged particle implosions and the mechanism of magnetic field growth. A giga-gauss magnetic field is generated and amplified with the opposite polarity to the seed magnetic field. The spot size of the field is comparable to the laser wavelength, and the lifetime is hundreds of femtoseconds. An analytical model is presented to explain the underlying physics. This study should aid in designing future experiments.

Dynamic mitigation of the tearing mode instability in a collisionless current sheet.

Dynamic mitigation for the tearing mode instability in the current sheet in collisionless plasmas is demonstrated by applying a wobbling electron current beam. The initial small amplitude modulations imposed on the current sheet induce the electric current filamentation and the reconnection of the magnetic field lines. When the wobbling or oscillatory motion is added from the electron beam having a form of a thin layer moving along the current sheet, the perturbation phase is mixed and consequently the instability growth is saturated remarkably, like in the case of the feed-forward control.

Enhanced photon emission from a double-layer target at moderate laser intensities.

In this paper we study photon emission in the interaction of the laser beam with an under-dense target and the attached reflecting plasma mirror. Photons are emitted due to the inverse Compton scattering when accelerated electrons interact with a reflected part of the laser pulse. The enhancement of photon generation in this configuration lies in using the laser pulse with a steep rising edge. Such a laser pulse can be obtained by the preceding interaction of the incoming laser pulse with a thin solid-density foil. Using numerical simulations we study how such a laser pulse affects photon emission. As a result of employing a laser pulse with a steep rising edge, accelerated electrons can interact directly with the most intense part of the laser pulse that enhances photon emission. This approach increases the number of created photons and improves photon beam divergence.

Intense, directional and tunable γ-ray emission via relativistic oscillating plasma mirror.

A mechanism for high energy γ-photon generation based on laser-plasma accelerator is proposed. The laser pulse with a peak intensity of 1022W/cm2 accelerates the electron beam to GeV by the laser wakefield effect. A solid Aluminium target serves as a plasma mirror which is located at the rear side of a gas jet and reflects the laser pulse. High order harmonics are generated due to the Doppler effect experienced by the incident laser. The collisions of the reflected attosecond pulses and the energetic electron beam provide a large cross section for nonlinear Compton scattering and produce a collimated γ-photon flux. The mechanism generates GeV photons with a pulse duration given by the duration of the electron beam.

[MIG7 Regulates the Vasculogenic Mimicry Formation in Hepatocellular Carcinoma then Effects the Metastasis Potential of HCC].

OBJECTIVES: To investigate the expression of migration-inducing gene 7 (MIG7) in different HCC lines and its relationship with vasculogenic mimicry (VM) formation and metastatic potentiality. METHODS: Employing immunostaining to detect MIG7 protein expression and VM formation in 40 matched pairs of primary and metastatic HCC specimens from 40 patients, and investigating the correlation of VM formation with MIG7 protein expression. Detecting VM formation in HCC lines with different metastatic ability (MHCC-97H, MHCC-97L, Huh-7) and human normal hepatocyte line (L-02) through three-dimensional culture, and detecting MIG7 mRNA expression with RT-PCR, investigating the correlation of MIG7 protein expression with VM formation and HCC metastatic potentiality with Western blot assay; screening the HCC cell line with high MIG7 expression. RESULTS: In 40 matched pairs of HCC tissue, there was a significant positive correlation between MIG7 protein expression and VM formation ( rs=0.595, P<0.01). The capability of VM formation of MHCC-97H with high metastatic potentiality was stronger than that of MHCC-97L with low metastatic potentiality and Huh-7 with non-metastatic potentiality, and there was no VM formation in L-02. The result of RT-PCR and Western blot assay indicated the same. CONCLUSIONS: MIG7 expression in HCC tissue is high and correlated positively with VM formation. MIG7 expression in different HCC cell lines is coincident with theirs VM formation, invasion and metastasis. MIG7 is a potential target for inhibiting the invasion and metastasis of HCC.

Functional human TSHß splice variant produced by plasma cell may be involved in the immunologic injury of thyroid in the patient with Hashimoto's thyroiditis.

Hashimoto's Thyroiditis (HT) is the most common cause of hypothyroidism in areas of the world where iodine levels are sufficient. However, the pathogenesis of HT has not been completely elucidated. The first functional human TSHß splice variant was supposed to be involved in the pathology of Hashimoto's thyroiditis. The question remains as to which kind of intrathyroid cells expresses functional TSHß splice variant and whether there are expression variations of functional TSHß splice variant in the injured thyroid of patient with HT. For the answer to this question, immune-injured thyroids were obtained from 30 patients with HT. Localization study of functional TSHß splice variant in injured thyroid was done by immunofluorescence double staining. Transcription and translation level of functional TSHß splice variant were detected by using qRT-PCR and semi-quantitative immunohistochemistry method, respectively. The correlation between expression level of functional TSHß splice variant and degree of thyroid follicles damage was assessed. It was firstly identified that functional TSHß splice variant was predominately expressed by plasma cells infiltrated around follicles and germinal center in injured thyroid of patient with HT. Of particular interest, the TSHß splice variant was expressed at significantly higher levels in the thyroid tissues of patients with HT than that in the normal thyroid tissues, furthermore, expression level of TSHß splice variant was positive related with the degree of follicles damage in thyroid of patient with HT. These findings defined the immune-derived functional TSHß splice variant that resided in the thyroid of patient with HT, which exerted the unique effects on the pathogenesis of HT, meanwhile, we considered these findings to have significant implications for understanding immune-endocrine interactions in a number of ways.

Laser ion acceleration toward future ion beam cancer therapy - Numerical simulation study -.

BACKGROUND: Ion beam has been used in cancer treatment, and has a unique preferable feature to deposit its main energy inside a human body so that cancer cell could be killed by the ion beam. However, conventional ion accelerator tends to be huge in its size and its cost. In this paper a future intense-laser ion accelerator is proposed to make the ion accelerator compact. SUBJECTS AND METHODS: An intense femtosecond pulsed laser was employed to accelerate ions. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching and the ion particle energy control. In the study particle computer simulations were performed to solve the issues, and each component was designed to control the ion beam quality. RESULTS: When an intense laser illuminates a target, electrons in the target are accelerated and leave from the target; temporarily a strong electric field is formed between the high-energy electrons and the target ions, and the target ions are accelerated. The energy efficiency from the laser to ions was improved by using a solid target with a fine sub-wavelength structure or by a near-critical density gas plasma. The ion beam collimation was realized by holes behind the solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching were successfully realized by a multi-stage laser-target interaction. CONCLUSIONS: The present study proposed a novel concept for a future compact laser ion accelerator, based on each component study required to control the ion beam quality and parameters.

[Human endostatin antiangiogenic gene therapy mediated by recombinant adeno-associated virus vector in nude mouse with endometriosis].

OBJECTIVE: To study the therapeutic effect of recombinant adeno-associated virus carrying human endostatin gene therapy on endometriosis in mice model. METHODS: Recombinant adeno-associated virus vector carrying human endostatin gene and enhanced green fluorescent proteins gene (rAAV2-endostatin-EGFP) was constructed. Endometrium was from 12 patients with leiomyoma undergoing hysterectomy in Second Hospital, Tianjin Medical University between November and December 2008. Endometriosis models of nude mice were established by transplanting human endometrial fragments intooperitoneal surface. After 1 week, those 60 mice were divided into 3 groups: treatment group including 20 mice injected with rAAV2-endostatin-EGFP to ectopic lesion, control group including 20 mice injected with rAAV2-EGFP to ectopic lesion and blank control group including 20 mice injected with phosphate buffered saline (PBS) to the ectopic lesion. At 1, 2 and 3 weeks after treatment, those mice underwent laparotomy to observe the location and size of ectopic lesion in abdominal cavity. The expression of endostain protein, number of gland, microvessel density (MVD) and vascular endothelial growth factor (VEGF) were measured in ectopic lesions. The serum level of estradiol and progesterone were detected in nude mice among every groups. RESULTS: (1) All endometriosis of nude mice models were established successfully through peritoneum transplanting. After 1 week's treatment, flat lesion nodes, decreased gland number and narrow and atrophy glandular cavity were observed by light microscope. (2) The endostatin gene was transferred into nude mice successfully and expressed effectively. It was observed that endostatin protein expression was shown with enhanced green fluorescent proteins in ectopic lesion. (3) Glands number of ectopic lesion in rAAV2-endostatin-EGFP group (7.8 ± 1.9, 7.0 ± 1.5 and 5.5 ± 1.7) were significantly less than 10.1 ± 1.7, 10.2 ± 2.0 and 9.8 ± 2.4 in rAAV2-EGFP control group and 10.2 ± 2.2, 10.0 ± 2.0 and 9.7 ± 2.2 in PBS control group at 1, 2 and 3 weeks after treatment (all P < 0.05). Glands number of ectopic lesion in rAAV2-endostatin-EGFP group at 3 weeks was significantly less than those at 1 and 2 weeks after treatment (P < 0.05). (4) MVD of ectopic lesion in rAAV2-endostatin-EGFP group (12.2 ± 1.5, 11.4 ± 2.1 and 9.0 ± 1.4) was significantly less than those at rAAV2-EGFP control group (16.5 ± 1.7, 16.5 ± 1.9 and 16.9 ± 1.9) and PBS control group (16.2 ± 1.6, 16.0 ± 1.6 and 16.3 ± 1.7) at 1, 2 and 3 weeks after treatment (all P < 0.05). MVD of ectopic lesion in rAAV2-endostatin-EGFP group at 3 weeks was significantly less than those at 1 and 2 weeks after treatment (P < 0.05). (5) The rate and density of VEGF expression at ectopic lesion in rAAV2-endostatin-EGFP group (35%, 30%, 25% and 1.60 ± 0.43, 1.33 ± 0.30, 1.03 ± 0.36) were significantly less than those at rAAV2-EGFP control group (80%, 75%, 85% and 2.43 ± 0.53, 2.43 ± 0.29, 2.66 ± 0.45) and PBS control group (85%, 90%, 90% and 2.36 ± 0.53, 2.64 ± 0.57, 2.53 ± 0.52) at one 1, 2 and 3 weeks after treatment (all P < 0.05). The expression of VEGF at ectopic lesion in rAAV2-endostatin-EGFP group at 3 weeks was significantly less than those at 1 and 2 weeks after treatment (P < 0.05). (6) The level of estradial and progesterone in serum of nude mice of rAAV2-endostatin-EGFP group [E(2): (48 ± 7) pmol/L, P: (61 ± 8) nmol/L] did not reach statistical difference when compared with those at rAAV2-EGFP control group [E(2): (50 ± 9) pmol/L, P: (60 ± 10) nmol/L] and PBS control group [E(2): (48 ± 7) pmol/L, P: (58 ± 10) nmol/L, P > 0.05]. CONCLUSIONS: The recombinant adeno-associated virus carrying human endostatin gene therapy could inhibit angiogenesis at endometriotic lesions and not influence steroid level. The antiangiogenic gene therapy might become a novel option for endometriosis.