310 research outputs found

    On spectra and Brown's spectral measures of elements in free products of matrix algebras

    Full text link
    We compute spectra and Brown measures of some non self-adjoint operators in (M_2(\cc), {1/2}Tr)*(M_2(\cc), {1/2}Tr), the reduced free product von Neumann algebra of M_2(\cc) with M_2(\cc). Examples include ABAB and A+BA+B, where A and B are matrices in (M_2(\cc), {1/2}Tr)*1 and 1*(M_2(\cc), {1/2}Tr), respectively. We prove that AB is an R-diagonal operator (in the sense of Nica and Speicher \cite{N-S1}) if and only if Tr(A)=Tr(B)=0. We show that if X=AB or X=A+B and A,B are not scalar matrices, then the Brown measure of X is not concentrated on a single point. By a theorem of Haagerup and Schultz \cite{H-S1}, we obtain that if X=AB or X=A+B and X≠λ1X\neq \lambda 1, then X has a nontrivial hyperinvariant subspace affiliated with (M_2(\cc), {1/2}Tr)*(M_2(\cc), {1/2}Tr).Comment: final version. to appear on Math. Sca

    Discovery of Novel Insulin Sensitizers: Promising Approaches and Targets

    Get PDF
    Insulin resistance is the undisputed root cause of type 2 diabetes mellitus (T2DM). There is currently an unmet demand for safe and effective insulin sensitizers, owing to the restricted prescription or removal from market of certain approved insulin sensitizers, such as thiazolidinediones (TZDs), because of safety concerns. Effective insulin sensitizers without TZD-like side effects will therefore be invaluable to diabetic patients. The specific focus on peroxisome proliferator-activated receptor γ- (PPARγ-) based agents in the past decades may have impeded the search for novel and safer insulin sensitizers. This review discusses possible directions and promising strategies for future research and development of novel insulin sensitizers and describes the potential targets of these agents. Direct PPARγ agonists, selective PPARγ modulators (sPPARγMs), PPARγ-sparing compounds (including ligands of the mitochondrial target of TZDs), agents that target the downstream effectors of PPARγ, along with agents, such as heat shock protein (HSP) inducers, 5′-adenosine monophosphate-activated protein kinase (AMPK) activators, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) selective inhibitors, biguanides, and chloroquines, which may be safer than traditional TZDs, have been described. This minireview thus aims to provide fresh perspectives for the development of a new generation of safe insulin sensitizers

    Effect of amber powder on endometrial ultrastructure and MAPK pathway in endometriosis model rats

    Get PDF
    Purpose: To explore the therapeutic role of amber powder in endometriosis by investigating its effect on endometrial ultrastructure, ERK1/2, p38MAPK, and NF-κB mRNA pathways and CSRC/EFR/ERK1/2 proteins. Methods: Sprague Dawley (SD) rats were randomly divided into blank group, disease model group (untreated), amber powder high-dose group, amber powder medium-dose group, amber powder lowdose group and danazol group. Morphological changes in endometrial cells were studied using transmission electron microscopy. The expression of ERK1/2, p38MAPK, and NF-κB mRNA in endometrial tissues of each group was determined using quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemistry was utilized for the measurement of C-SRC/EFR/ERK1/2 pathway protein expression. Results: The endometriosis rats treated with a high-, medium- and low-dose amber powder showed a decrease in the volume of ectopic lesions, compared with the untreated disease model group. The expressions of ERK1/2, p38MAPK, NF-κB mRNA, and C-SRC/EFR/ERK1/2 protein were higher in the eutopic and ectopic endometrial tissues in untreated disease group than those in normal control group. Moreover, treatment of endometriosis rats with amber powder revealed a reduction in the expressions of ERK1/2, p38MAPK, NF-κB mRNA and C-SRC/EFR/ERK1/2 proteins in eutopic and ectopic endometrium tissues. Conclusion: Amber powder reduces ectopic lesions and slows down the development of endometriosis, probably via inhibition of MAPK pathway genes in eutopic and ectopic endometrial tissues

    Franck-Condon Factors and Radiative Lifetime of the A^{2}\Pi_{1/2} - X^{2}\Sigma^{+} Transition of Ytterbium Monoflouride, YbF

    Full text link
    The fluorescence spectrum resulting from laser excitation of the A^{2}\Pi_{1/2} - X^{2}\Sigma^{+} (0,0) band of ytterbium monofluoride, YbF, has been recorded and analyzed to determine the Franck-Condon factors. The measured values are compared with those predicted from Rydberg-Klein-Rees (RKR) potential energy curves. From the fluorescence decay curve the radiative lifetime of the A^{2}\Pi_{1/2} state is measured to be 28\pm2 ns, and the corresponding transition dipole moment is 4.39\pm0.16 D. The implications for laser cooling YbF are discussed.Comment: 5 pages, 5 figure

    SIRT1 Activation by Resveratrol Alleviates Cardiac Dysfunction via Mitochondrial Regulation in Diabetic Cardiomyopathy Mice

    Get PDF
    Background. Diabetic cardiomyopathy (DCM) is a major threat for diabetic patients. Silent information regulator 1 (SIRT1) has a regulatory effect on mitochondrial dynamics, which is associated with DCM pathological changes. Our study aims to investigate whether resveratrol, a SRIT1 activator, could exert a protective effect against DCM. Methods and Results. Cardiac-specific SIRT1 knockout (SIRT1KO) mice were generated using Cre-loxP system. SIRT1KO mice displayed symptoms of DCM, including cardiac hypertrophy and dysfunction, insulin resistance, and abnormal glucose metabolism. DCM and SIRT1KO hearts showed impaired mitochondrial biogenesis and function, while SIRT1 activation by resveratrol reversed this in DCM mice. High glucose caused increased apoptosis, impaired mitochondrial biogenesis, and function in cardiomyocytes, which was alleviated by resveratrol. SIRT1 deletion by both SIRT1KO and shRNA abolished the beneficial effects of resveratrol. Furthermore, the function of SIRT1 is mediated via the deacetylation effect on peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), thus inducing increased expression of nuclear respiratory factor 1 (NRF-1), NRF-2, estrogen-related receptor-α (ERR-α), and mitochondrial transcription factor A (TFAM). Conclusions. Cardiac deletion of SIRT1 caused phenotypes resembling DCM. Activation of SIRT1 by resveratrol ameliorated cardiac injuries in DCM through PGC-1α-mediated mitochondrial regulation. Collectively, SIRT1 may serve as a potential therapeutic target for DCM

    Manganese oxide electrode with excellent electrochemical performance for sodium ion batteries by pre-intercalation of K and Na ions

    Full text link
    Materials with a layered structure have attracted tremendous attention because of their unique properties. The ultrathin nanosheet structure can result in extremely rapid intercalation/de-intercalation of Na ions in the charge-discharge progress. Herein, we report a manganese oxide with pre-intercalated K and Na ions and having flower-like ultrathin layered structure, which was synthesized by a facile but efficient hydrothermal method under mild condition. The pre-intercalation of Na and K ions facilitates the access of electrolyte ions and shortens the ion diffusion pathways. The layered manganese oxide shows ultrahigh specific capacity when it is used as cathode material for sodium-ion batteries. It also exhibits excellent stability and reversibility. It was found that the amount of intercalated Na ions is approximately 71% of the total charge. The prominent electrochemical performance of the manganese oxide demonstrates the importance of design and synthesis of pre-intercalated ultrathin layered materials

    Rapid determination of 103 common veterinary drug residues in milk and dairy products by ultra performance liquid chromatography tandem mass spectrometry

    Get PDF
    A multi-residue method has been developed for the identification and quantification of 103 common veterinary drug residues in milk and dairy Products. This method was based on QuEChERS with dispersive solid-phase where C18 sorbent and anhydrous sodium sulfate were used to sample purification. After evaporation and reconstitution, the samples were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry. The mean recovery results were all higher than 60% except ampicillin, pipemidic acid, enoxacin, and estriol, and the relative standard deviation was <20.0%. The limit of quantification ranged between 0.1 and 5 μg/kg for milk and between 0.5 and 25 μg/kg for milk powder. It was successfully used to detect residues of veterinary drug in real samples. This study proposes a simple and fast analytical method for monitoring multi-class veterinary drug residues to ensure food safety

    Control and Data Flow Execution of Java Programs

    Full text link
    Since decade understanding of programs has become a compulsory task for the students as well as for others who are involved in the process of developing software and providing solutions to open problems. In that aspect showing the problem in a pictorial presentation in a best manner is a key advantage to better understand it. We provide model and structure for Java programs to understand the control and data flow analysis of execution. Especially it helps to understand the static analysis of Java programs, which is an uttermost important phase for software maintenance. We provided information and model for visualization of Java programs that may help better understanding of programs for a learning and analysis purpose. The idea provided for building visualization tool is extracting data and control analysis from execution of Java programs. We presented case studies to prove that our idea is most important for better understanding of Java programs which may help towards static analysis, software debugging and software maintenance
    • …
    corecore