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[en] AIM: To present the findings of uterine artery embolization (UAE) in the management of obstetric haemorrhage. MATERIALS AND METHODS: From October 1999 to February 2003, 10 women with postpartum haemorrhage (n=7) and post-abortion haemorrhage with placenta accreta (n=3), were referred to our department for pelvic angiography and possible arterial embolization. RESULTS: Angiography revealed engorged and tortuous uterine arteries in all patients; and contrast medium extravasation in three patients. Eight patients (three with and five without detectable active bleeding) then underwent bilateral UAE. Medium-sized (250-355 μm) polyvinyl alcohol particles were injected via a coaxial catheter into the uterine arteries, followed by gelatin sponge pieces via a 4 F Cobra catheter. Microcoil devascularization was also performed in the two patients with visible, active bleeding. The vaginal bleeding resolved in all patients, without any ischaemic complications. At follow-up, all patients who underwent UAE had normal menstruation; three of them subsequently gave birth to full-term healthy babies. CONCLUSION: Selective UAE by the coaxial method is safe and effective to control obstetric haemorrhage, with the potential to preserve fertility
[en] Reaction of recoil 38Cl atoms with o-dichlorobenzene in the presence of carbon tetrachloride or iodine has been studied by using radio-high performance liquid chromatography. The major products were detected by a 4-channel-wavelengths spectrophotometric detector. The radioactivity of 38Cl compounds including minor products was measured with a NaI(Tl) scintillation detector. The main products found were 38Cl labeled HCl/Cl2, CHCl3, CCl4, o-, p-, m-C6H6Cl2 and polymer,, whereas only miner products such as HCl/CR2, C2,Cl6, C6H3Cl3, and polymer were found in the radio-chromatogram. The reaction mechanisms of recoil 38Cl atom are briefly described. (author) 9 refs.; 5 figs.; 3 tabs
[en] In order to avoid the highly concentrated electric field induced beneath the sharp tip, the technique using a top coating electrode in the piezoresponse force microscopy (PFM) has been developed to detect the piezoelectric coefficients. Reliable theory should be erected to explain the broadly reported top electrode size effects and relate the responses with material constants. In this paper, the surface displacement, electric potential inside the film, electric charge and effective piezoelectric coefficient are expressed as a set of integral equations. Analytical solutions are obtained for two limiting cases, i.e., half space (HS) and infinitely thin film (IT). The effective piezoelectric coefficient of the HS case is proved to be the same as that from the PFM of a piezoelectric half plane without a top coating. For the IT case, it is identical to the well-known piezoelectric coefficient result of piezoelectric thin film clamped between flat rigid electrodes subject to homogeneous external electric field. For PZT4 thin layer, numerical results reveal that the surface displacement obviously decreases and the electric potential distributions inside the film become more and more homogeneous as the electrode radius to film thickness ratio (a/t) enlarges. The electric charge dramatically increases while the effective piezoelectric coefficient evidently decreases and they both transfer from the HS solutions to the IT results when a/t varies from 0.001 to 20. The transition occurs at about a/t = 1 in agreement with the experimental observations. A critical top electrode size, i.e., a/t > 10, is obtained and applicable to other piezoelectric materials. Under such circumstances, one can readily gain the piezoelectric coefficients e 33, d 33 and the dielectric coefficient if other mechanical coefficients and one piezoelectric constant are known a prior. (paper)
[en] In the Standard Model of particle physics, quarks and anti-quarks have fractional charges equal to ±1/3 or ±2/3 of the electron's charge. There has been a large number of experiments searching for fractional charge particles using a variety of methods, including dE/dx ionization energy loss measurements in e+e− collisions, but no evidence has been found to confirm existence of free fractional charge particles, which leads to the quark confinement theory. In this paper, a proposal to search for fractional charge particles is presented, which is based on the conservation law of four-momentum and the Lorentz force law. To show the power of the new strategy, a fully BESIII detector simulated signal sample mixed with a fully simulated background sample is analyzed and lower signal cross section limits to discover 5σ signal as a function of quark mass are estimated for the background. The analysis result shows that in comparison with ionization energy loss measurements, the advantage of the strategy is that it can identify fractional charge particles without using any theoretical or empirical formulae to calculate any expected observation values.
[en] ZnO nanocrystals embedded in SiO2 matrix thin films were fabricated on Si (1 0 0) single crystal substrates by plasma enhanced chemical vapour deposition (PECVD) at 230 deg. C. Subsequently, the as-deposited samples were annealed at different temperatures ranging from 500 deg. C to 900 deg. C, respectively. The effects of annealing temperature on optical properties of the thin films were investigated by Raman spectra and photoluminescence spectra. The results indicate that the annealing process can promote crystallinity and optical properties of the thin films, and that the optimized annealing temperature is 800 deg. C. They also suggest that the UV band originates from free exciton recombination, and the wide emission bands located from 2.71 to 2.91 eV are originated from localized trapping levels relating to the interface between ZnO and SiO2
[en] This paper presents a numerical investigation on the three-dimensional interaction between two bow shock waves in two environments, i.e. ground high-enthalpy wind tunnel test and real space flight, using Fluent 15.0. The first bow shock wave, also called induced shock wave, which is generated by the leading edge of a hypersonic vehicle. The other bow shock wave can be deemed objective shock wave, which is generated by the cowl clip of hypersonic inlet, and in this paper the inlet is represented by a wedge shaped nose cone. The interaction performances including flow field structures, aerodynamic pressure and heating are analyzed and compared between the ground test and the real space flight. Through the analysis and comparison, we can find the following important phenomena: 1) Three-dimensional complicated flow structures appear in both cases, but only in the real space flight condition, a local two-dimensional type IV interaction appears; 2) The heat flux and pressure in the interaction region are much larger than those in the no-interaction region in both cases, but the peak values of the heat flux and pressure in real space flight are smaller than those in ground test. 3) The interaction region on the objective surface are different in the two cases, and there is a peak value displacement of 3 mm along the stagnation line. (paper)
[en] Polymer bonded explosives (PBXs) are a kind of rubbery explosives, in which the explosive components are bound together by a polymeric binder. The hydroxyl terminated polybutadiene (HTPB)-based polyurethane binder systems possess a unique combination of properties, including superior adhesion, excellent mechanical properties and have been widely used in rocket propellants, PBXs and other weapons. The cure reaction between HTPB and diisocyanates in the castable PBXs plays an important role in the adjustment of process parameters as well as properties of explosive formulations. In this paper, viscosity measurements were carried out at different temperatures (15oC, 25oC, 35oC, 45oC, 55oC) to a series of systemic studies on the viscosity build-up and rheological reaction rate constant during the curing process of the of HTPB- dioctyl adipate (DOA)-diphenyl methane diisocyanate (MDI) binder system, discovered and explained the phenomenon that the pot-life of the binder system was prolonged when the curing temperature raised and the curing reaction rate was accelerated. And the rheology kinetic model of the HTPB-DOA-MDI binder system was established. (paper)
[en] 1-Methyl-3,5-dinitro-1,2,4-triazole is an insensitive energetic compound that can be prepared by oxidizing the nitrate salt of 1-methylguanazole. The influence of the reaction time, reaction temperature, reactant ratio, feeding method and catalytic oxidation method on the yield were discussed. The results show that the optimum reaction conditions are as follows: mass ratio of sodium tungstate to nitrate salt to 1-methylguanazole, 4:4.4; time, 5.5h; and temperature, 65-75°C. The yield of this oxidation reaction reached 51.36%. (paper)
[en] The Cu-Fe composite oxides were prepared by an epoxide assisted sol-gel route. The structural and magnetic properties of Cu-Fe composite oxides calcinated at different temperatures were determined by X-ray diffraction (XRD), Mössbauer spectroscopy measurements, and magnetic measurements. These results indicated that CuFe2O4 was only formed as calcination temperature increased to 500 °C, and a crystalline phase transformation from c-CuFe2O4 to t-CuFe2O4 occurred in elevating calcination temperature above it. All Cu-Fe oxides had ferromagnetic nature, and the significant superparamagnetic behavior was observed in the results of magnetic and Mössbauer spectroscopy measurements.
[en] Minimal residual disease (MRD) is of the most important factor for predicting prognosis and guiding treatment of acute lymphoblastic leukemia (ALL). In this study, we investigated the prognostic significance of leukemia-associated immunophenotypes (LAIPs) as assessment of index of MRD in 125 adult B-lineage ALL (B-ALL) patients by eight-color flow cytometry. The LAIPs could be identified in 96% and 81.6% of patients with the sensitivity of 10−4 and 10−5, respectively. MRD-negative status could clearly predict a favorable 2-year relapse-free survival (RFS) and overall survival (OS) at the end of induction of complete remission and one cycle of consolidation treatment. Moreover, we identified a group of cases with MRD of 0.001% to <0.01%, which showed significantly higher 2-year relapse rate than those with undetectable one. In multivariate analysis, MRD status was associated with RFS or OS independently. Furthermore, MRD assessed by LAIPs and RQ-PCR assay for patients with BCR-ABL fusion gene yielded concordant results in 89.7% of cases. In conclusion, MRD evaluated by eight-color flow cytometry could provide an important tool to assess treatment response and prognosis precisely in adult B-ALL