2,338 research outputs found

    Asymptotic distributions of the signal-to-interference ratios of LMMSE detection in multiuser communications

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    Let sk=1N(v1k,...,vNk)T,{\mathbf{s}}_k=\frac{1}{\sqrt{N}}(v_{1k},...,v_{Nk})^T, k=1,...,Kk=1,...,K, where {vik,i,k\{v_{ik},i,k =1,...}=1,...\} are independent and identically distributed random variables with Ev11=0Ev_{11}=0 and Ev112=1Ev_{11}^2=1. Let Sk=(s1,...,sk1,{\mathbf{S}}_k=({\mathbf{s}}_1,...,{\mathbf{s}}_{k-1}, sk+1,...,sK){\mathbf{s}}_{k+1},...,{\mathbf{s}}_K), Pk=diag(p1,...,{\mathbf{P}}_k=\operatorname {diag}(p_1,..., pk1,pk+1,...,pK)p_{k-1},p_{k+1},...,p_K) and \beta_k=p_k{\mathbf{s}}_k^T({\mathb f{S}}_k{\mathbf{P}}_k{\mathbf{S}}_k^T+\sigma^2{\mathbf{I}})^{-1}{\math bf{s}}_k, where pk0p_k\geq 0 and the βk\beta_k is referred to as the signal-to-interference ratio (SIR) of user kk with linear minimum mean-square error (LMMSE) detection in wireless communications. The joint distribution of the SIRs for a finite number of users and the empirical distribution of all users' SIRs are both investigated in this paper when KK and NN tend to infinity with the limit of their ratio being positive constant. Moreover, the sum of the SIRs of all users, after subtracting a proper value, is shown to have a Gaussian limit.Comment: Published at http://dx.doi.org/10.1214/105051606000000718 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Application of stratified emulsion splitting technology in highly hard nuclear cataract surgery

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    AIM:To explore safety and effectiveness of stratified emulsion splitting technology in highly hard nuclear cataract ultrasonic emulsification. METHODS: Totally 43 cases(47 eyes)of highly hard nuclear cataract was performed cataract extraction combined IOL implantation with stratified emulsion splitting cataract ultrasonic emulsification technology. RESULTS:Postoperative visual acuity 1 day, 1 week and 1 month best-corrected visual acuity ≥0.5 was accounted for 70.21%, 87.23% and 89.36%. Intraoperative capsule rupture was found in 2 eyes. Corneal mild edema was found in 7 eyes(14.89%)after the first l day post-operation. CONCLUSION:Stratified emulsion splitting technique has a practical application with little tissue damage, low capsular rupture rate and few complications for highly hard nuclear cataract patients and can bring a desirable outcome

    Portal Vein Thrombosis in Liver Cirrhosis

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    In liver cirrhosis, portal vein thrombosis (PVT), which is defined as thrombosis that occurs within the main portal vein and intrahepatic portal branches, is one of the most common complications. High incidence of PVT in the setting of liver cirrhosis is mainly due to hypercoagulable state and altered dynamic of blood flow in the portal vein. The clinical manifestations of PVT are variable among different patients, so the diagnosis of PVT is mainly dependent on the imaging examinations, like ultrasound, computed tomography and magnetic resonance imaging. The overall goal of treatment for PVT can be summarized as reducing risk factors of PVT, thus to prevent further expansion of thrombus and maintain portal patency and prevent and treat the symptoms of PVT by anticoagulants, local thrombolysis, transjugular intrahepatic portosystemic shunt and/or surgery. In future, due to the progress in vascular imaging and innovation in clinical anti-thrombotic drug, PVT could be prevented and cured effectively

    Miniaturization of Branch-Line Coupler Using Composite Right/Left-Handed Transmission Lines with Novel Meander-shaped-slots CSSRR

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    A novel compact-size branch-line coupler using composite right/left-handed transmission lines is proposed in this paper. In order to obtain miniaturization, composite right/left-handed transmission lines with novel complementary split single ring resonators which are realized by loading a pair of meander-shaped-slots in the split of the ring are designed. This novel coupler occupies only 22.8% of the area of the conventional approach at 0.7 GHz. The proposed coupler can be implemented by using the standard printed-circuit-board etching processes without any implementation of lumped elements and via-holes, making it very useful for wireless communication systems. The agreement between measured and stimulated results validates the feasible configuration of the proposed coupler

    Unusual Compression Behavior of Columbite TiO2 via First-Principles Calculations

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    The physical mechanisms behind the reduction of the bulk modulus of a high-pressure cubic TiO2 phase are confirmed by first-principles calculations. An unusual and abrupt change occurs in the dependence of energy on pressure at 43 GPa, indicating a pressure-induced phase transition from columbite TiO2 to a newly-identified modified fluorite TiO2 with a Pca21 symmetry. Oxygen atom displacement in Pca21 TiO2 unexpectedly reduces the bulk modulus by 34% relative to fluorite TiO2. This discovering provides a direct evidence for understanding the compressive properties of such groups of homologous materialsComment: [email protected] or [email protected]

    Sulforaphane Rescues Ethanol-Suppressed Angiogenesis through Oxidative and Endoplasmic Reticulum Stress in Chick Embryos

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    Our previous study showed that ethanol exposure inhibited embryonic angiogenesis mainly due to the excessive stimulation of reactive oxygen species (ROS) production. In this study, we investigated whether sulforaphane (SFN), a known dietary bioactive compound, could ameliorate ethanol-suppressed angiogenesis using chick embryo angiogenesis models. Using chick yolk sac membrane (YSM) and chorioallantoic membrane (CAM) models, we demonstrated that administration of low concentrations of SFN (2.5–10 μM) alone increased angiogenesis, but high concentrations of SFN (20–40 μM) inhibited angiogenesis. SFN administration alleviated ethanol-suppressed angiogenesis and angiogenesis-related gene expression in both angiogenesis models. Ethanol exposure caused cell apoptosis in chick CAM, and the cell apoptosis could be remitted by administration of SFN. Subsequently, we demonstrated that the ethanol-induced increase in production of ROS and reduction of antioxidant enzymes’ activity were partially rescued by SFN. Similar results were obtained in endoplasmic reticulum (ER) stress determination, indicated by ATF6 and GRP78 expression or thapsigargin-induced ER stress in the presence or absence of SFN. Taken together, our experiments show that SFN administration can ameliorate ethanol-suppressed embryonic angiogenesis, and this is mainly achieved by alleviating excessive ROS production and ER stress. This study suggests that SFN, in appropriate concentrations, could be a potential candidate compound for preventing the negative impact of alcohol on angiogenesis

    Sulforaphane Rescues Ethanol-Suppressed Angiogenesis through Oxidative and Endoplasmic Reticulum Stress in Chick Embryos

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    Our previous study showed that ethanol exposure inhibited embryonic angiogenesis mainly due to the excessive stimulation of reactive oxygen species (ROS) production. In this study, we investigated whether sulforaphane (SFN), a known dietary bioactive compound, could ameliorate ethanol-suppressed angiogenesis using chick embryo angiogenesis models. Using chick yolk sac membrane (YSM) and chorioallantoic membrane (CAM) models, we demonstrated that administration of low concentrations of SFN (2.5–10 μM) alone increased angiogenesis, but high concentrations of SFN (20–40 μM) inhibited angiogenesis. SFN administration alleviated ethanol-suppressed angiogenesis and angiogenesis-related gene expression in both angiogenesis models. Ethanol exposure caused cell apoptosis in chick CAM, and the cell apoptosis could be remitted by administration of SFN. Subsequently, we demonstrated that the ethanol-induced increase in production of ROS and reduction of antioxidant enzymes’ activity were partially rescued by SFN. Similar results were obtained in endoplasmic reticulum (ER) stress determination, indicated by ATF6 and GRP78 expression or thapsigargin-induced ER stress in the presence or absence of SFN. Taken together, our experiments show that SFN administration can ameliorate ethanol-suppressed embryonic angiogenesis, and this is mainly achieved by alleviating excessive ROS production and ER stress. This study suggests that SFN, in appropriate concentrations, could be a potential candidate compound for preventing the negative impact of alcohol on angiogenesis

    Zc(3900)Z_c(3900) as a DDˉD\bar{D}^* molecule from the pole counting rule

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    A comprehensive study on the nature of the Zc(3900)Z_c(3900) resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a unified description to all the relevant experimental data available, including the J/ψπJ/\psi\pi and ππ\pi\pi invariant mass distributions from the e+eJ/ψππe^+e^-\to J/\psi\pi\pi process, the hcπh_c\pi distribution from e+ehcππe^+e^-\to h_c\pi\pi and also the DDˉD\bar D^{*} spectrum in the e+eDDˉπe^+e^-\to D\bar D^{*}\pi process. After fitting the unknown parameters to the previous data, we search the pole in the complex energy plane and find only one pole in the nearby energy region in different Riemann sheets. Therefore we conclude that Zc(3900)Z_c(3900) is of DDˉD\bar D^* molecular nature, according to the pole counting rule method~[Nucl.~Phys.~A543, 632 (1992); Phys.~Rev.~D 35,~1633 (1987)]. We emphasize that the conclusion based upon the pole counting method is not trivial, since both the DDˉD\bar D^{*} contact interactions and the explicit ZcZ_c exchanges are introduced in our analyses and they lead to the same conclusion.Comment: 21 pages, 9 figures. To match the published version in PRD. Additional discussion on the spectral density function is include

    Determination of berberine and berberrubine in rabbit plasma by capillary electrophoresis with amperometric detection and its application to pharmacokinetic study

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    A simple and selective method based on capillary electrophoresis with amperometric detection has been developed for the separation and determination of berberine (BB) and berberrubine (BBR) in rabbit plasma. The working electrode was a 150 μm diameter platinum microelectrode at a detection potential of +1.1 V (versus Ag/AgCl). The analytes could be well separated within 6 min in a 50 cm length fused-silica capillary at a separation voltage of 15 kV in a 50 mmol/L phosphate buffer (pH 6.0). Calibration curve was linear over the range of 0.002-20 μg/mL. The detection limits (S/N = 3) were 1.0 and 0.8 ng/mL for BB and BBR, respectively. Relative standard deviations (R.S.D.) of not more than 6.0 % were obtained for both migration times and electrophoretic peak area. The proposed method was successfully used to analyze the drugs in samples of rabbit plasma for pharmacokinetic study.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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