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In the hohlraum used in laser indirect-drive inertial confinement fusion experiments, hydrodynamic processes of radiation-ablated high-Z plasma have a great effect on laser injection efficiency, radiation uniformity, and diagnosis of hohlraum radiation field from diagnostic windows (DW). To study plasma filling in the DWs, a laser-irradiated Ti disk was used to generate 2-5 keV narrow energy band X-ray as the intense backlighter source, and laser-produced X-ray in a hohlraum with low-Z foam tamper was used to heat a small hole surrounded by gold wall with 150 μm in diameter and 100 μm deep. The hydrodynamic movement of the gold plasma in the small hole was measured by an X-ray framing camera and the results are analyzed. Quantitative measurement of the plasma areal density distribution and evolution in the small hole can be used to assess the effect of plasma filling on the diagnosis from the DWs. [ABSTRACT FROM AUTHOR]

Radiation flow through gold-doped hydrocarbon foam is investigated and a model is presented to calculate effective opacity for an inhomogeneous, pressure-equilibrated gold/foam mixture based on the Levermore-Pomraning method for binary stochastic media. The effective opacity dependance on the size of the gold particles and the foam temperature are studied. The results suggest that when the mixture temperature is lower than 250 eV, the opacity difference between the 5 &mgr;m particle mix case and the atomic mix case is large enough to induce a significant discrepancy in radiation transport, which is confirmed by the hydrodynamic simulation. [ABSTRACT FROM AUTHOR]

X-ray streak cameras are extensively used to study transient x-ray processes in experiments carried out on various laser facilities at the Research Center of Laser Fusion. Precise calibration and clear description of the sweep speed of the x-ray streak camera are vital for obtaining precise temporal information to understand the fast physics phenomena. An x-ray streak camera named wide-slit x-ray streak camera has been calibrated using a small-scale laser facility with pulse duration of 8 ps. Sweep speeds on most part of the output screen (charge coupled device) are obtained. These calibration results can be used to correct the nonlinearity of sweep speed in measurement of temporal processes. [ABSTRACT FROM AUTHOR]

As an important x-ray source, enhancement of x-ray emissions from laser-produced plasmas is significant for various applications. Due to less expanding kinetic loss, gold foam with low initial density can have an enhanced x-ray conversion efficiency compared with solid-density gold. However, low-Z impurities within gold foam targets will diminish the enhancement remarkably, and should be tightly controlled. This paper presents an experimental study of a high brightness laser plasma soft x-ray source, based on a g gold foam target with negligible impurities irradiated by nanosecond laser pulses with power density around 3  ×  10 W at the Shenguang II laser facility. A conversion efficiency, from multi-eV to multi-keV, of % is achieved in the x-ray emissions—about 21% relative enhancement compared with a solid-density gold target, and the highest conversion efficiency for Au foam planar targets yet. Good agreement has been achieved between the semi-analytical model prediction and the experimental results. [ABSTRACT FROM AUTHOR]

Fluorescence imaging of surrogate Si-doped CH targets has been used to provide a measurement for drive condition of high-energy x-ray (i.e. M-band x-ray) drive symmetry upon the capsule in hohlraum on Shenguang-II laser facility. A series of experiments dedicated to the study of photo-pumping and fluorescence effect in Si-plasma are presented. To investigate the feasibility of fluorescence imaging in Si-plasma, an silicon plasma in Si-foil target is pre-formed at ground state by the soft x-ray from a half-hohlraum, which is then photo-pumped by the K-shell lines from a spatially distinct laser-produced Si-plasma. The resonant Si photon pump is used to improve the fluorescence signal and cause visible image in the Si-foil. Preliminary fluorescence imaging of Si-ball target is performed in both Si-doped and pure Au hohlraum. The usual capsule at the center of the hohlraum is replaced with a solid Si-doped CH-ball (Si-ball). Since the fluorescence is proportional to the photon pump upon the Si-plasma, high-energy x-ray drive symmetry is equal to the fluorescence distribution of the Si-ball. [ABSTRACT FROM AUTHOR]

The K-shell emission spectra of laser-produced aluminum plasma are measured by a space-resolved spectrometer consisting of a flat crystal spectrometer with a 20 um wide space-resolved slit. By using the approximation of the steady collisional-radiative equilibrium model, the interstage line intensity ratios of Ly-a resonance line to He-a resonance line are given as a function of electron temperature. The spectra profiles are decomposed to resonance line and the overlapped high-order satellites manifold. Thus reliable electron temperature is deduced from the interstage line intensity ratios of the decomposed resonance lines. The results of spaced-resolved temperature are compared with the hydrodynamic simulations. The diagnostics of electron temperature for laser-produced plasma is developed. [ABSTRACT FROM AUTHOR]

A technique of flat crystal x-ray spectrometer for quantitative spectral measurement is described. For the flat crystal spectrograph geometry, the quantitative reduction of relating the CCD counts back to the photon flux from the x-ray source is established. The absolute calibrations of the integral diffraction coefficients of the crystal and the CCD sensitivity make it possible to measure absolute photons flux within the energy range of 2000-5000 eV. The uncertainty analysis of the calibrations is carried out to obtain the energy resolved uncertainties of crystal and CCD. Thus, the experimental spectra with spectral resolved intensity uncertainties are available. Then, a performing experiment of laser-produced Ti plasma is carried out and the absolute x-ray spectra with intensity uncertainty less than 8.5% are obtained. The technique is promising for absolute spectral measurement of high temperature plasmas in a kilo-electron-volt region. [ABSTRACT FROM AUTHOR]

Integral diffraction coefficients of the crystal are the essential data of a crystal spectrometer which is extensively used to measure quantitative x-ray spectra of high temperature plasmas in kilo-electron-volt region. An experimental method has been developed to measure the integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility. The integral diffraction coefficients of several crystals including polyethylene terephthalate (PET), thallium acid phthalate (TlAP) and rubidium acid phthalate (RAP) crystals have been measured in the x-ray energy range 2100-5600 eV and compared with the calculations of the 'Darwin Prins' and the 'Mosaic' models. It is shown that the integral diffraction coefficients of these crystals are between the calculations of the 'Darwin Prins' and the 'Mosaic' models, but more close to the 'Darwin Prins' model calculations. [ABSTRACT FROM AUTHOR]

Background: Betatrophin is a novel adipokine that provokes pancreatic β-cell proliferation and is involved in lipid metabolism. Aims: This study aims to evaluate the role of serum betatrophin in metabolic syndrome (MetS). Methods: A hospital-based, age-/gender-matched case control study was conducted. The serum betatrophin level was evaluated by enzyme- linked immunosorbent assay. Serum concentrations of 12 adipokines were measured to assess their associations with serum betatrophin, using commercial Adipokine Magnetic Bead Panel kits. Statistical analyses included bivariate correlation, receiver operating characteristic (ROC) curve, and multivariate stepwise linear regression. Results: Serum betatrophin showed a higher level in MetS patients (997.36 ± 475.92 pg/ml, p = 0.001) compared with controls (735.35 ± 526.51 pg/ml). Compared with the lowest tertile, the highest tertile of serum betatrophin level indicated an association with higher risk of MetS (adjusted odds ratio = 3.521, 95% confidence interval [CI] [1.191-10.413], p = 0.023). ROC curve of betatrophin was developed to predict the presence of MetS (area under ROC = 0.682 [95% CI, 0.597-0.767], p < 0.001). Furthermore, betatrophin correlated with several parameters, e.g. age (r = 0.286, p < 0.001), body mass index (r = 0.160, p = 0.046), waist-to-hip ratio (r = 0.241, p = 0.002), high-density lipoprotein cholesterol (r = -0.167, p = 0.037), low-density lipoprotein cholesterol (r = -0.195, p = 0.015), fasting plasma glucose (r = 0.266, p = 0.001), hemoglobin A1C (r = 0.314, p < 0.001), homeostasis model assessment of insulin resistance (r = 0.272, p = 0.001), and various adipokines, e.g. resistin (r = 0.571, p < 0.001), interleukin-8 (r = 0.435, p < 0.001), tumor necrosis factor-α (r = 0.295, p = 0.011) and lipocalin-2 (r = 0.346, p = 0.003). Conclusions: This study supports that serum betatrophin plays an important role in MetS, involving the regulations of glucose and lipid metabolism and inflammation. [ABSTRACT FROM AUTHOR]

Aim: To analyze the benefits and harms of pancreatic cancer screening in familial high-risk individuals (HRIs)., Methods: Studies were identified by searching PubMed, EBSCO, ClinicalTrials.gov and the Cochrane database from database inception to June 2014. We also obtained papers from the reference lists of pertinent studies and systematic reviews. English-language trials and observational studies were searched. The key words used as search terms were "screening" and "surveillance". Cost-effectiveness, diagnostic rate, survival rate, mortality and adverse events were the outcomes of interest. Age, sex, lifestyle and other confounding factors were also considered. However, anticipating only a few of these studies, we also included observational studies with or without control groups. We also included studies concerning the anxiety associated with pancreatic cancer risk and other psychological changes in familial HRIs. We extracted details on study design, objectives, population characteristics, inclusion criteria, year of enrollment, method of screening, adjusted and unadjusted mortality, cost-effectiveness and adverse events from the included studies. Studies were assessed using the Reporting of Observational studies in Epidemiology (STROBE) checklist., Results: Sixteen studies on pancreatic cancer screening were included. Five studies included control groups, nine were observational studies without control groups, and the other two studies investigated the worry associated with pancreatic cancer risk. We found that pancreatic cancer screening resulted in a high curative resection rate (60% vs 25%, P = 0.011), longer median survival time (14.5 mo vs 4 mo, P < 0.001), and higher 3-year survival rate (20% vs 15.0%, P = 0.624). We also found that familial HRIs had a higher diagnostic rate of pancreatic tumors than controls (34% vs 7.2%, P < 0.001). In patients who underwent regular physical examinations, more stage I pancreatic cancers were observed (19% vs 2.6%, P = 0.001). In addition, endoscopic ultrasonography, which was the main means of detection, diagnosed 64.3% of pancreatic cancers. In comparison, endoscopic retrograde cannulation of the pancreas, magnetic resonance imaging, and computed tomography diagnosed 28.6%, 42.9%, and 21.4%, respectively. For mass lesions, instant surgery was recommended because of the beneficial effects of post-operative chemotherapy. However, in patients with intraductal papillary mucinous neoplasms, we did not find a significant difference in outcome between surgery and follow-up without treatment. Moreover, pancreatic cancer screening in familial HRIs had a greater perceived risk of pancreatic cancer (P < 0.0001), higher levels of anxiety regarding pancreatic cancer (P < 0.0001), and increased economic burden., Conclusion: Pancreatic cancer screening in familial HRIs is associated with a higher detection rate and longer survival, although screening may influence psychological function and increase the economic burden.

Aim: To investigate whether Helicobacter pylori (H. pylori) infection is associated with glycemic control and whether hyperglycemia is modified by eradication therapy., Methods: The databases of PubMed, Cochrane Library, Chinese BioMedicine Web Base and Chinese Science and Technology Journals were searched from inception to June 2014. Studies examining the association between H. pylori infection and glycemic control and/or the effect of eradication treatment on glycemic control in diabetic humans were eligible for inclusion. Meta-analyses were conducted using the Review Manager software version 5.2. The outcome measures are presented as weighed mean differences (WMDs) with 95% confidence intervals (CIs). Statistical heterogeneity was assessed by the Cochran Q test and the I(2) statistic., Results: A total of 21 relevant publications were identified. A meta-analysis of 11 studies with 513 patients with diabetes mellitus (DM) showed significantly lower glycosylated hemoglobin (HbA1c) levels in the H. pylori-negative than H. pylori-positive DM participants (WMD = 0.43, 95%CI: 0.07-0.79; P = 0.02). In children and adolescents with type 1 DM (T1DM), there was a positive association between H. pylori infection and HbA1c level (WMD = 0.35, 95%CI: 0.05-0.64; P = 0.02), but there was no difference in those with type 2 DM (T2DM, WMD = 0.51, 95%CI: -0.63-1.65; P = 0.38). A meta-analysis of six studies with 325 T2DM participants showed a significant difference in the fasting plasma glucose levels between H. pylori-positive and H. pylori-negative participants (WMD = 1.20, 95%CI: 0.17-2.23; P = 0.02). Eradication of H. pylori did not improve glycemic control in the T2DM participants in a three-month follow-up period (HbA1c decrease: WMD = -0.03, 95%CI = -0.14-0.08; P = 0.57; fasting plasma glucose decrease: WMD = -0.06, 95%CI: -0.36-0.23; P = 0.68). Glycemic control was significantly better in T1DM participants who were not reinfected than in those who were reinfected (HbA1c: WMD = 0.72, 95%CI: 0.32-1.13: P = 0.00)., Conclusion: H. pylori infection is associated with poorer glycemic control in T1DM patients, but eradication may not improve glycemic control in DM in a short-term follow-up period.