173 research outputs found
Codes cross-correlation analysis and data/pilot code pairs optimization for Galileo E1 OS and GPS L1C
AbstractThe Galileo E1 open service (OS) and the global positioning system (GPS) L1C are intending to use the multiplexed binary offset carrier (MBOC) modulation in E1/L1 band, including both pilot and data components. The impact of data and pilot codes cross-correlation on the distortion of the discriminator function (i.e., the S-curve) is investigated, when only the pilot (or data) components of MBOC signals are tracked. It is shown that the modulation schemes and the receiver configuration (e.g., the correlator spacing) strongly affect the S-curve bias. In this paper, two methods are proposed to optimize the data/pilot code pairs of Galileo E1 OS and GPS L1C. The optimization goal is to obtain the minimum average S-curve bias when tracking only the pilot components a the specific correlator spacing. Figures of merit, such as S-curve bias, correlation loss and code tracking variance have been adopted for analyzing and comparing the un-optimized and optimized code pairs. Simulation results show that the optimized data/pilot code pairs could significantly mitigate the intra-channel codes cross-correlation, and then improve the code tracking performance of MBOC signals
Diversified pattern of the human colorectal cancer microbiome
BACKGROUND: The aim of this study is to expand existing knowledge about the CRC-associated microbiome among Han Chinese, and to further discover the variation pattern of the human CRC microbiome across all population. FINDINGS: Using pyrosequencing-based molecular monitoring of bacterial 16S rRNA gene from eight tumor/normal tissue pairs of eight Chinese CRC patients, we analyzed and characterized the basic features of the CRC-associated microbiome. Firstly, we discovered an increasing diversity among tumor-associated bacterial communities. Secondly, in 50% of Chinese CRC patients, we found a significant increase of Roseburia (P = 0.017), and a concurrent decrease of both Microbacterium (P = 0.009) and Anoxybacillus (P = 0.009) in tumor tissue. CONCLUSIONS: We discovered a novel CRC microbiome pattern in Chinese. Both the over-represented Roseburia bacteria at tumor sites and the over-represented Microbacterium and Anoxybacillus bacteria away from tumor sites were both closely related in Chinese CRC patients. Across several populations reported in this study and previously, we observed both common and distinctive patterns of human CRC microbiome’s association with a high-risk of CRC
Toward Success of 2 + 2 Collaborative Program In School of Engineering Between UB and China
In 2013, the University of Bridgeport (UB) in the United States (U.S.) and the Wuhan University of Science and Technology (WUST) in People’s Republic of China (China) agreed on an undergraduate collaborative program in electrical engineering. Students admitted by Department of Electrical Engineering (EE) of WUST will study in China for 2 years, then students can be transferred to the same program of UB in the U.S. for the remaining academic requirements at UB. Upon the completion of all graduation requirements at UB, students will receive a Bachelor of Science in EE from UB. Students who stay all four years at WUST or transferred to UB after two years, will be granted a Certificate of Graduation and a Bachelor’s degree from WUST if they are subject to satisfactory completion of the program
Atomic oxygen adsorption and incipient oxidation of the Pb(111) surface: A density-functional theory study
We study the atomic oxygen adsorption on Pb(111) surface by using
density-functional theory within the generalized gradient approximation and a
supercell approach. The atomic and energetic properties of purely on-surface
and subsurface oxygen structures at the Pb(111) surface are systematically
investigated for a wide range of coverages and adsorption sites. The fcc and
tetra-II sites (see the text for definition) are found to be energetically
preferred for the on-surface and subsurface adsorption, respectively, in the
whole range of coverage considered. The on-surface and subsurface oxygen
binding energies monotonically increase with the coverage, and the latter is
always higher than the former, thus indicating the tendency to the formation of
oxygen islands (clusters) and the higher stability of subsurface adsorption.
The on-surface and subsurface diffusion-path energetics of atomic oxygen, and
the activation barriers for the O penetration from the on-surface to the
subsurface sites are presented at low and high coverages. In particular, it is
shown that the penetration barrier from the on-surface hcp to the subsurface
tetra-I site is as small as 65 meV at low coverage (=0.25). The other
properties of the O/Pb(111) system, including the charge distribution, the
lattice relaxation, the work function, and the electronic density of states,
are also studied and discussed in detail, which consistently show the gradually
stabilizing ionic O-Pb bond with increase of the oxygen coverage.Comment: 31 pages, 16 figure
Solution of the ultimate bearing capacity at the tip of a pile in inclined rocks based on the Hoek-Brown criterion
To investigate the bearing mechanism of piles in inclined slope, this paper proposed an analytical method through geometric transformation to calculate the ultimate bearing capacity at the tip of a pile in inclined rocks based on the characteristic line method. It was found that there were five failure modes for piles in inclined rocks depending on the embedment ratios, slope angles, average overburden load and tensile strength parameter of the rock mass. When the pile failure mode was under the modes of deep pile with minor overburden (DL) and deep pile with major overburden (DH), the ultimate bearing capacity had no change as the slope angle and the pile embedment ratio changed. When the pile was under the failure modes of semi-deep pile with minor overburden (SL), semi-deep pile with major overburden (SH) or shallow pile (SS), the ultimate bearing capacity decreased with an increasing rate as the slope angles increased; and to get the same ultimate bearing capacity at the pile tip, the pile embedment ratio should increase. The proposed analytical method can be served as an efficient method to estimate the bearing capacity of piles in inclined slope with small slope angle (typically less than 40°)
Quantum blockade and loop current induced by a single lattice defect in graphene nanoribbons
We investigate theoretically the electronic transport properties in narrow
graphene ribbons with an adatom-induced defect. It is found that the lowest
conductance step of a metallic graphene nanoribbon may develop a dip even down
to zero at certain values of the Fermi energy due to the defect. Accompanying
the occurrence of the conductance dip, a loop current develops around the
defect. We show how the properties of the conductance dip depend on the
parameters of the defect, such as the relative position and severity of the
defect as well as the width and edges of the graphene ribbons. In particular,
for metallic armchair-edges graphene nanoribbons, whether the conductance dip
appears or not, they can be controlled by choosing the position of the single
defect.Comment: 6 pages, 6 figure
Hemoglobin level is negatively associated with sarcopenia and its components in Chinese aged 60 and above
Introduction: Sarcopenia and low hemoglobin level are common in older adults. Few studies have evaluated the association between hemoglobin level and sarcopenia and with inconsistent findings. The multifaceted effects of sarcopenia on the human body and the high prevalence of anemia in the Chinese population make it necessary to explore the association between the two. Methods: Using the China Health and Retirement Longitudinal Study (CHARLS), we explored the association between hemoglobin with sarcopenia and its components in the Chinese population aged 60 and above. Multivariate logistic and Cox proportional hazards models were constructed to examine the association of hemoglobin level with sarcopenia and sarcopenia components in individuals aged 60 years or above. The subgroup analysis covered residence, body mass index level, drinking status, and smoking status were conducted. The possible difference of associations between sexes was also explored. Results: With a total of 3,055 people, the hemoglobin concentration in people without sarcopenia, possible sarcopenia, and sarcopenia are 14.34 ± 2.22, 14.64 ± 2.27, and 13.58 ± 2.02 g/dl, respectively. Cross-sectional analysis showed strong evidence that hemoglobin was negatively associated with sarcopenia [Odds Ratio (OR) = 0.95, 95% Confidence Interval (CI): 0.90–0.99] and low height-adjusted appendicular skeletal muscle mass (OR = 0.91, 95% CI: 0.86–0.97). On average, a per 1 g/dl higher hemoglobin level was associated with 5% lower odds of sarcopenia (OR = 0.95, 95% CI: 0.90–0.98). The cohort study of 1,022 people demonstrated a statistically significant negative association of hemoglobin level with low physical performance [Hazard Ratio (HR) = 0.92, 95% CI: 0.85–0.99], merely with sarcopenia (HR = 0.92, 95% CI: 0.84–1.00) and skeletal muscle mass (HR = 0.95, 95% CI: 0.80–1.00). Sex-specific analysis suggested hemoglobin's association with sarcopenia, muscle mass, and physical performance in all sexes, with weaker magnitudes in females. Hemoglobin in urban residents and people with high body mass index (BMI) has a larger magnitude of the negative association with sarcopenia. Discussion: Hemoglobin level associates with sarcopenia, muscle mass, and physical performance in the Chinese population aged 60 and above, with sex-specific, residence-specific, and BMI-specific effects
SLIT2/ROBO1-miR-218-1-RET/PLAG1: a new disease pathway involved in Hirschsprung\u27s disease.
Hirschsprung\u27s disease (HSCR) is a rare congenital disease caused by impaired proliferation and migration of neural crest cells. We investigated changes in expression of microRNAs (miRNAs) and the genes they regulate in tissues of patients with HSCR. Quantitative real-time PCR and immunoblot analyses were used to measure levels of miRNA, mRNAs, and proteins in colon tissues from 69 patients with HSCR and 49 individuals without HSCR (controls). Direct interactions between miRNAs and specific mRNAs were indentified in vitro, while the function role of miR-218-1 was investigated by using miR-218 transgenic mice. An increased level of miR-218-1 correlated with increased levels of SLIT2 and decreased levels of RET and PLAG1 mRNA and protein. The reductions in RET and PLAG1 by miR-218-1 reduced proliferation and migration of SH-SY5Y cells. Overexpression of the secreted form of SLIT2 inhibited cell migration via binding to its receptor ROBO1. Bowel tissues from miR-218-1 transgenic mice had nerve fibre hyperplasia and reduced numbers of gangliocytes, compared with wild-type mice. Altered miR-218-1 regulation of SLIT2, RET and PLAG1 might be involved in the pathogenesis of HSCR
Real-time monitoring for road-base quality with the aid of buried piezoelectric sensors
The road-base usually deteriorate during service time due to factors such as cyclical traffic loads and road-base fouling. Currently the monitoring method for road-base quality is quite limited. This paper proposes a real-time Monitoring method for Road-Base Quality (MRBQ) based on a soil dynamic model and piezoelectric sensors buried in road-base. The soil dynamic model was extended with a piezoelectric equation to calculate the voltage in the road-base generated by a moving traffic load. Then, a model test was conducted to measure the output voltage of the piezoelectric sensors buried in the road-base. Finally, the road-base modulus was back-calculated through the soil dynamic model with the measured voltage. The back-calculated modulus was compared with the modulus measured by resonance column test (RCT) to validate this method. The unique relationship between the peak voltage and the road-base modulus at various depths was identified for different traffic load amplitudes and speeds, and the feasibility and accuracy of the MRBQ was demonstrated. This study reveals that the sensitivity of the piezoelectric sensors can reach 2 V/MPa, and the error to measure the road-base modulus is less than 20%. The proposed MRBQ demonstrates a good application potential in health monitoring of transportation facilities
A Comparative Investigation on Various Platinum Nanoparticles Decorated Carbon Supports for Oxygen Reduction Reaction
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