1,946 research outputs found
Beauty mesons in lattice QCD with exact chiral symmetry
We present the first study of treating b, c, and s quarks as Dirac fermions
in lattice QCD with exact chiral symmetry. For 100 gauge configurations
generated with single-plaquette action at beta = 7.2 on the 32^3 x 60 lattice,
we compute point-to-point quark propagators for 33 quark masses in the range
0.01 < m_q a < 0.85, and measure the time-correlation function of
(pseudo-)scalar, (pseudo-)vector, and tensor mesons, for symmetric and
asymmetric quark masses respectively. The lowest-lying mass spectra of mesons
with quark contents b_bbar, c_bbar, s_bbar, and c_cbar are determined, together
with the pseudoscalar decay constants. Our results are sumarized in Tables 1-5.
Furthermore, we also determine the b and c quark masses in the MS_bar scheme,
m_b = 4.65(5) GeV, and m_c = 1.16(4) GeV.Comment: 12 page
Pseudoscalar Meson in Two Flavors QCD with the Optimal Domain-Wall Fermion
We perform hybrid Monte Carlo (HMC) simulatons of two flavors QCD with the
optimal domain-wall fermion (ODWF) on the 16^3 x 32 lattice (with lattice
spacing a ~ 0.1 fm), for eight sea-quark masses corresponding to pion masses in
the range 228-565 MeV. We calculate the mass and the decay constant of the
pseudoscalar meson, and compare our data with the chiral perturbation theory
(ChPT). We find that our data is in good agreement with the sea-quark mass
dependence predicted by the next-to-leading order (NLO) ChPT, and provides a
determination of the low-energy constants \bar{l}_3 and \bar{l}_4, the pion
decay constant, the chiral condensate, and the average up and down quark mass.Comment: 12 pages, v2: updated results with full statistic
Outcomes in Neonates with Pulmonary Atresia and Intact Ventricular Septum Underwent Pulmonary Valvulotomy and Valvuloplasty Using a Flexible 2-French Radiofrequency Catheter
Purpose : Outcomes in 6 neonates with pulmonary atresia and intact ventricular septum (PAIVS) Undergoing radiofrequency pulmonary valvulotomy and valvuloplasty (RPVV) were reported to identify the factors favorable for RPVV as the treatment of choice. Materials and Methods: From May 2000 to January 2008, 6 patients with PAWS were included in this retrospective study. They were aged I day to 90 days old. Study modalities included review of recordings of presentations and profiles of chest radiography, electrocardiography, echocardiography, and cardiac catheterization with angiography. Hemodynamic profiles from the echocardiography and the cardiac catheterization were analyzed. Results: Echocardiography showed severe tricuspid regurgitation, membranous atresia of the pulmonary valve, intact ventricular septum, patent ductus arteriosus, and hypoplastic right ventricle in 6 patients. The pulmonary valve annulus were 4.2 to 6.9 mm in diameters, and those of the tricuspid valve were 7.1 to 10.1 mm. Elevated serum level of cardiac enzymes were found in 1 patient with ventriculocoronary communication (VCC). At cardiac catheterization, the ratio of systolic pressure of the right ventricle to that of the left ventricle ranged from 1.43 to 2.33 before RPVV, and from 0.54 to 1.15 after RPVV ((p=0. 027). The pressure gradients ranged from 76 to 136 mmHg before RPVV, and from 15 to 39 mmHg after RPVV (p=0.028). The echocardiographic gradients ranged from 16 to 32 mmHg within 24 hours after RPVV, and from 15 to 50 mmHg at the follow-ups. Conclusion: RPVV can be a treatment of choice for neonates with PAIVS, if there is patent infundibulum, no right-ventricular dependent coronary circulation, and adequate tricuspid valve and pulmonary valve
New Plasma Separation Glucose Oxidase-based Glucometer in Monitoring of Blood With Different PO2 Levels
BackgroundThe PalmLab glucometer is a newly designed plasma separation glucose oxidase (GO)-based glucometer. Past studies have shown that the accuracy of GO-based glucometers is compromised when measurements are taken in patients with high PO2 levels. We performed a two-arm study comparing the fitness of the PalmLab blood glucometer with that of a standard glucose analyzer in monitoring blood glucose levels in pediatric patients, especially when arterial partial pressure of oxygen (PO2) was high.MethodsIn the first arm of the study, arterial blood samples from pediatric patients were measured by the PalmLab blood glucometer and the YSI 2302 Plus Glucose/Lactate analyzer. In the second arm of the study, venous blood samples from adult volunteers were spiked with glucose water to prepare three different levels of glucose (65, 150, and 300mg/dL) and then oxygenated to six levels of PO2 (range, 40–400mmHg). The biases of the PalmLab glucometer were calculated.ResultsA total of 162 samples were collected in the first arm of the study. Results of linear regression showed that the coefficient of determination (R2) between PalmLab glucometer and standard glucose analyzer was 0.9864. Error grid analysis revealed that all the results were within Zone A (clinically accurate estimate zone). The biases between the two systems were low at different PO2 levels. In the second arm of the study, the results were also unaffected by changes in PO2.ConclusionThe PalmLab glucometer provides accurate results in samples with high PO2 and is suitable for measuring arterial glucose levels in pediatric patients
Protective Effect of Caffeic Acid on Paclitaxel Induced Anti-Proliferation and Apoptosis of Lung Cancer Cells Involves NF-κB Pathway
Caffeic acid (CA), a natural phenolic compound, is abundant in medicinal plants. CA possesses multiple biological effects such as anti-bacterial and anti-cancer growth. CA was also reported to induce fore stomach and kidney tumors in a mouse model. Here we used two human lung cancer cell lines, A549 and H1299, to clarify the role of CA in cancer cell proliferation. The growth assay showed that CA moderately promoted the proliferation of the lung cancer cells. Furthermore, pre-treatment of CA rescues the proliferation inhibition induced by a sub-IC50 dose of paclitaxel (PTX), an anticancer drug. Western blot showed that CA up-regulated the pro-survival proteins survivin and Bcl-2, the down-stream targets of NF-κB. This is consistent with the observation that CA induced nuclear translocation of NF-κB p65. Our study suggested that the pro-survival effect of CA on PTX-treated lung cancer cells is mediated through a NF-κB signaling pathway. This may provide mechanistic insights into the chemoresistance of cancer calls
The effect of exercise on the risk of metabolic syndrome associated with sleep insufficiency: a cross-sectional study
IntroductionSleep disturbance and insufficient sleep have been linked to metabolic syndrome, increasing cardiovascular disease and mortality risk. However, few studies investigate the joint effect of sleep and exercise on metabolic syndrome. We hypothesized that regular exercise can mitigate the exacerbation of metabolic syndrome by sleep insufficiency.ObjectiveThe aim of this study was to investigate whether exercise can attenuate or eliminate the relationship between sleep insufficiency and metabolic syndrome.MethodA total of 6,289 adults (mean age = 33.96 years; women: 74.81%) were included in the study, a cross-sectional study conducted based on the results of employee health screening questionnaires and databases from a large healthcare system in central Taiwan. Participants reported sleep insufficiency or not. Self-reported exercise habits were classified into 3 levels: no exercise, exercise <150 min/week, and exercise ≧150 min/week. Multiple logistic regression and sensitivity analyses were conducted to understand the joint associations of sleep patterns and exercise with metabolic syndrome with exposure variables combining sleep duration/disturbances and PA.ResultsCompared with the reference group (sufficient sleep), individuals with sleep insufficiency had a higher risk for metabolic syndrome [adjusted odds ratio (AOR) = 1.40, 95% confidence interval (95% CI): 1.01–1.94, p < 0.05] in females aged 40–64 years, but not in other populations. Sleep insufficiency was not associated with the risk of metabolic syndrome among individuals achieving an exercise level of <150 min/week, and in particular among those achieving ≧150 min/week in all populations in our study.ConclusionSleep insufficiency was related to a higher risk of metabolic syndrome in female healthcare staff aged 40–64 years. Being physically active with exercise habits in these individuals, the risk of metabolic syndrome was no longer significant
Identification of genes related to the development of bamboo rhizome bud
Bamboo (Phyllostachys praecox) is one of the largest members of the grass family Poaceae, and is one of the most economically important crops in Asia. However, complete knowledge of bamboo development and its molecular mechanisms is still lacking. In the present study, the differences in anatomical structure among rhizome buds, rhizome shoots, and bamboo shoots were compared, and several genes related to the development of the bamboo rhizome bud were identified. The rice cross-species microarray hybridization showed a total of 318 up-regulated and 339 down-regulated genes, including those involved in regulation and signalling, metabolism, and stress, and also cell wall-related genes, in the bamboo rhizome buds versus the leaves. By referring to the functional dissection of the homologous genes from Arabidopsis and rice, the putative functions of the 52 up-regulated genes in the bamboo rhizome bud were described. Six genes related to the development of the bamboo rhizome bud were further cloned and sequenced. These show 66–90% nucleotide identity and 68–98% amino acid identity with the homologous rice genes. The expression patterns of these genes revealed significant differences in rhizome shoots, rhizome buds, bamboo shoots, leaves, and young florets. Furthermore, in situ hybridization showed that the PpRLK1 gene is expressed in the procambium and is closely related to meristem development of bamboo shoots. The PpHB1 gene is expressed at the tips of bamboo shoots and procambium, and is closely related to rhizome bud formation and procambial development. To our knowledge, this is the first report that uses rice cross-species hybridization to identify genes related to bamboo rhizome bud development, and thereby contributes to the further understanding of the molecular mechanism involved in bamboo rhizome bud development
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