9,493 research outputs found
On the variable capacity property of CC/DS-CDMA systems
A complete complementary code based direct sequence code
division multiple access (CC/DS-CDMA) system has been proposed recently
as a potential candidate for beyond third generation (B3G) wireless
communications. This paper addresses the issues that design of efficient
code assignment schemes should be based on a flexible physical layer
support, which is extremely important for emerging cross-layer designs
in future wireless applications. The study in this paper considers a
CC/DS-CDMA system with multiple time slots, three traffic classes and
two dynamic code-flock assignment schemes, namely random assignment
(RA) and compact assignment (CA). Simulation results show that the
CC/DS-CDMA system has variable capacity property (VCP), which is
sensitively affected by different code-flock assignment schemes. In general,
CA can offer lower blocking probability, whereas RA can offer a larger
mean system capacity and higher throughput when offered traffic is heavy
Correlation between the cyclin A and p53 gene expression in oral carcinogenesis
published_or_final_versio
First observation of psi(2S)-->K_S K_L
The decay psi(2S)-->K_S K_L is observed for the first time using psi(2S) data
collected with the Beijing Spectrometer (BESII) at the Beijing Electron
Positron Collider (BEPC); the branching ratio is determined to be
B(psi(2S)-->K_S K_L) = (5.24\pm 0.47 \pm 0.48)\times 10^{-5}. Compared with
J/psi-->K_S K_L, the psi(2S) branching ratio is enhanced relative to the
prediction of the perturbative QCD ``12%'' rule. The result, together with the
branching ratios of psi(2S) decays to other pseudoscalar meson pairs
(\pi^+\pi^- and K^+K^-), is used to investigate the relative phase between the
three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.Comment: 5 pages, 4 figures, 2 tables, submitted to Phys. Rev. Let
Unique pattern of infections in chronic granulomatous disease – The Asian experience
Conference Theme: Inflammatory Basis of Perinatal and Childhood DiseasesSymposium 40: InfectionBackground: Chronic granulomatous disease (CGD) is a phagocytic disorder
caused by defective NADPH oxidase activity. Affected individuals are susceptible
to bacterial infections, mycosis and hyperinflammatory complications. Variations
in the epidemiology of infectious diseases across geographical regions can lead
to distinct clinical phenotypes.
Objective: To identify the unique clinical characteristics of a large cohort of CGD
patients in China and Southeast Asia referred for genetic studies from 2003 to
2012.
Methods: 53 patients with genetically-confirmed CGD were included and their
clinical features were analyzed. CYBB and CYBA mutations were studied by
Sanger sequencing, and NCF1 ‘GT’ deletion hotspot mutation was studied on
genomic DNA by GeneScan.
Results: 44 patients with X-CGD had CYBB mutations (missense[n=16];
nonsense[n=8]; deletion[n=9]; insertion[n=2]; intron mutation[n=9]). Nine
patient had AR-CGD (CYBA[n=5]; NCF1 75_76delGT[n=4]). The median age at
presentation and diagnosis was higher in AR-CGD (7m and 66m) compared with
X-CGD (3m and 22m). The commonest presentations were pneumonia (58%), skin and perianal abscess (49%), lymphadenitis (42%) and recurrent diarrhea (30%).
Aspergillosis and salmonellosis occurred at a frequency similar to published
studies (13% and 19% respectively), but the commonest infection was BCG (43%)
and 11% had disseminated BCG. 21% of patients had tuberculosis. Fulminant
melioidosis and Chromobacterium violaceum infections occurred in 3 patients
and two of their male siblings. Hyperinflammatory conditions included polyarthritis
(n=3) and pulmonary granuloma (n=2). Death was recorded in 8 patients (15%).
Conclusion: Melioidosis and C. violaceum indigenous to Southeast Asia can cause
life-threatening infections in CGD patients. The high incidence of mycobacterial
infections is associated with universal BCG vaccination and endemicity of
tuberculosis. Such observations emphasize the role of respiratory burst as an
immune defense mechanism against these pathogens. These infections are
seldom reported in Caucasian cohorts, illustrating the importance of regional
collaborative studies to facilitate pattern recognition and early diagnosis of
primary immunodeficiencies.published_or_final_versio
Empirical likelihood estimation of the spatial quantile regression
The spatial quantile regression model is a useful and flexible model for analysis of empirical problems with spatial dimension. This paper introduces an alternative estimator for this model. The properties of the proposed estimator are discussed in a comparative perspective with regard to the other available estimators. Simulation evidence on the small sample properties of the proposed estimator is provided. The proposed estimator is feasible and preferable when the model contains multiple spatial weighting matrices. Furthermore, a version of the proposed estimator based on the exponentially tilted empirical likelihood could be beneficial if model misspecification is suspect
Disentangling astroglial physiology with a realistic cell model in silico
Electrically non-excitable astroglia take up neurotransmitters, buffer extracellular K+ and generate Ca2+ signals that release molecular regulators of neural circuitry. The underlying machinery remains enigmatic, mainly because the sponge-like astrocyte morphology has been difficult to access experimentally or explore theoretically. Here, we systematically incorporate multi-scale, tri-dimensional astroglial architecture into a realistic multi-compartmental cell model, which we constrain by empirical tests and integrate into the NEURON computational biophysical environment. This approach is implemented as a flexible astrocyte-model builder ASTRO. As a proof-of-concept, we explore an in silico astrocyte to evaluate basic cell physiology features inaccessible experimentally. Our simulations suggest that currents generated by glutamate transporters or K+ channels have negligible distant effects on membrane voltage and that individual astrocytes can successfully handle extracellular K+ hotspots. We show how intracellular Ca2+ buffers affect Ca2+ waves and why the classical Ca2+ sparks-and-puffs mechanism is theoretically compatible with common readouts of astroglial Ca2+ imaging
Quantised Vortices in an Exciton-Polariton Fluid
One of the most striking quantum effects in a low temperature interacting
Bose gas is superfluidity. First observed in liquid 4He, this phenomenon has
been intensively studied in a variety of systems for its amazing features such
as the persistence of superflows and the quantization of the angular momentum
of vortices. The achievement of Bose-Einstein condensation (BEC) in dilute
atomic gases provided an exceptional opportunity to observe and study
superfluidity in an extremely clean and controlled environment. In the solid
state, Bose-Einstein condensation of exciton polaritons has now been reported
several times. Polaritons are strongly interacting light-matter
quasi-particles, naturally occurring in semiconductor microcavities in the
strong coupling regime and constitute a very interesting example of composite
bosons. Even though pioneering experiments have recently addressed the
propagation of a fluid of coherent polaritons, still no conclusive evidence is
yet available of its superfluid nature. In the present Letter, we report the
observation of spontaneous formation of pinned quantised vortices in the
Bose-condensed phase of a polariton fluid by means of phase and amplitude
imaging. Theoretical insight into the possible origin of such vortices is
presented in terms of a generalised Gross-Pitaevskii equation. The implications
of our observations concerning the superfluid nature of the non-equilibrium
polariton fluid are finally discussed.Comment: 14 pages, 4 figure
Measurement of the Branching Fraction of J/psi --> pi+ pi- pi0
Using 58 million J/psi and 14 million psi' decays obtained by the BESII
experiment, the branching fraction of J/psi --> pi+ pi- pi0 is determined. The
result is (2.10+/-0.12)X10^{-2}, which is significantly higher than previous
measurements.Comment: 9 pages, 8 figures, RevTex
Hepatitis B Virus Core Promoter Double Mutations (A1762T, G1764A) Are Associated with Lower Levels of Serum Dihydrolipoyl Dehydrogenase
Published by S. Karger AG, BaselObjectives: The aim of this study was to identify serum proteins with differential concentrations between hepatocellular carcinoma (HCC) patients and HBsAg asymptomatic carriers among individuals infected with hepatitis B virus (HBV) with basal core promoter (BCP) double mutations (A1762T, G1764A). Methods: iTRAQ and liquid chromatography-tandem mass spectrometry were used to identify differentially expressed protein, and an ELISA test was used for the validation test. Results: The total number of proteins identified was 1,125, of which 239 showed statistically significant differences in their expression. The relative concentrations of serum dihydrolipoyl dehydrogenase (DLD), which showed the most significant correlation with liver diseases and infection, were significantly lower in HCC patients than asymptomatic HBsAg carriers and individuals negative for HBsAg. However, only the difference between HCC patients with BCP double mutations and HBsAg-negative individuals could be confirmed by ELISA. Meanwhile, we found that the concentrations of serum DLD in those infected with HBV with BCP double mutations were significantly lower than in individuals with the wild-type BCP. However, the difference in the concentrations of serum DLD between individuals with wild-type BCP and those negative for HBsAg was not significant. Conclusions: HBV with BCP double mutations are associated with lower concentrations of serum DLD
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