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Abstract: Dense phase pneumatic conveying experiment of rice husk powder and blendings of rice husk and coal was carried out at the pressure of up to 4.0MPa in an experimental facility. Effects of operation conditions and mixing ratios of rice husk and coal on conveying behaviours were investigated. Results indicated that superficial gas velocity increased as total conveying differential pressure and supplemental gas flow rate increased, respectively. Solid loading ratio increased with increasing total conveying differential pressure, but decreased with increasing supplemental gas flow rate. Under the same operation conditions, superficial gas velocity decreased with the increasing in content of coal in blendings, while solid loading ratio increased gradually. The flow stability analysis results indicated that conveyings of blendings were more stable than that of pure rice husk, the flow stability was improved by adding coal. Characteristics of pressure drops in horizontal pipe, vertical pipe, horizontal bend and vertical bend were presented. Empirical correlations of additional pressure drop coefficients and pressure drops of vertical pipe, horizontal pipe, vertical bend and horizontal bend were proposed. [Copyright &y& Elsevier]

Background: Geographic differences exist in the antibiotic resistance patterns of Helicobacter pylori. Personalized treatment regimens based on local or individual resistance data are essential. We evaluated the current status of H. pylori resistance in Ningxia, analyzed resistance‐related factors, and assessed the concordance of phenotypic and genotypic resistance. Methods: Strains were isolated from the gastric mucosa of patients infected with H. pylori in Ningxia and relevant clinical information was collected. Phenotypic antibiotic susceptibility assays (Kirby–Bauer disk diffusion) and antibiotic resistance gene detection (Sanger sequencing) were performed. Results: We isolated 1955 H. pylori strains. The resistance rates of H. pylori to amoxicillin, levofloxacin, clarithromycin, and metronidazole were 0.9%, 42.4%, 40.4%, and 94.2%, respectively. Only five tetracycline‐resistant and one furazolidone‐resistant strain were identified. Overall, 3.3% of the strains were sensitive to all six antibiotics. Multidrug‐resistant strains accounted for 22.9%, of which less than 20% were from Wuzhong. Strains isolated from women and patients with nonulcerative disease had higher rates of resistance to levofloxacin and clarithromycin. Higher rates of resistance to metronidazole, levofloxacin, and clarithromycin were observed in the older age group than in the younger age group. The kappa coefficients of phenotypic resistance and genotypic resistance for levofloxacin and clarithromycin were 0.830 and 0.809, respectively, whereas the remaining antibiotics showed poor agreement. Conclusion: H. pylori antibiotic resistance is severe in Ningxia. Therefore, furazolidone, amoxicillin, and tetracycline are better choices for the empirical therapy of H. pylori infection in this region. Host sex, age, and the presence of ulcerative diseases may affect antibiotic resistance of the bacteria. Personalized therapy based on genetic testing for levofloxacin and clarithromycin resistance may be a future direction for the eradication therapy of H. pylori infection in Ningxia. [ABSTRACT FROM AUTHOR]

The structural, electronic, and magnetic properties of two-dimensional (2D) manganese dibromide (MnBr2) and manganese diiodide (MnI2) are investigated using first principles calculations. The dynamical and thermal stabilities of 2D MnBr2 and MnI2 have been illustrated from the phonon dispersion and molecular dynamic calculations. From the phonon dispersion, three Raman-active and three infrared-active vibration modes are found. The calculated formation energies and cleavage energies indicate that 2D MnBr2 and MnI2 are energetically stable and could be potentially obtained by exfoliation. The hybrid functional theory is employed to discover that 2D MnBr2 and MnI2 are wide gap semiconductors. The magnetic frustration is revealed by the calculation of magnetic exchange interaction and magnetocrystalline anisotropy interaction. By analyzing different magnetic orders, the relatively weak magnetic exchange is attributed to the competition of the direct exchange and the superexchange interaction. [ABSTRACT FROM AUTHOR]

• Contact surface boundary conditions between the two surfaces of the vertical crack were considered to study contact acoustic nonlinearity (CAN) from the breathing contact crack in conjunction with the modal decomposition method, Fourier transform, and variational principle-based algorithm. • The clapping effects when the crack closed due to the different ratios of incident wave amplitude to crack width with the contact boundary conditions between the crack surfaces were studied and analyzed to get the quantitative correlation between analytical calculations and FE simulation. • When the crack state was modulated at a low frequency (much lower than the one of the probing ultrasonic waves), the related mode conversion coefficients were modulated accordingly both in the fundamental frequency and harmonic frequency. To characterize fatigue crack, an analytical calculation and finite element (FE) simulation of Lamb wave propagating through the region of a breathing crack in a two-dimensional(2D) isotropic plate were studied. Contact surface boundary conditions between the two surfaces of the vertical crack were considered to study contact acoustic nonlinearity (CAN) from the breathing contact crack in conjunction with the modal decomposition method, Fourier transform, and variational principle-based algorithm. Reflection and transmission coefficients in the fundamental frequency and second harmonic frequency were calculated and analyzed quantitatively. Different ratios of incident wave amplitude to crack width were studied to calculate CAN results related to micro-crack width. In addition, a low-frequency (LF) vibration(10 Hz) excitation was introduced to perturb the free surface vertical crack to close, and an interrogating Lamb wave(1 MHz) was used to study crack-related CAN in different conditions for interpreting the modulation mechanism. The contact boundary conditions between two surfaces of vertical crack were set which were dynamically changed due to the low frequency modulation. The clapping effects when the crack closed due to the modulation of the contact boundary conditions between the crack surfaces were studied and analyzed to get the quantitative correlation between CAN and LF modulation. The results obtained from the analytical model were compared with those from the FE simulation, showing good consistency. Knowledge of these effects is essential to correctly gauge the severity of surface cracks in the plate, which can be spotlighted in its application to quantitative evaluation of micro fatigue cracks in structural health monitoring(SHM). [ABSTRACT FROM AUTHOR]

Objectives: This study on human papillomavirus (HPV) testing in China's largest independent laboratory accredited by the international Laboratory Accreditation Program of the College of American Pathologists extends previous reports on cervical screening test results from this Chinese facility.Methods: A retrospective laboratory database search from 2007 to 2014 documented high-risk HPV test results using either Hybrid Capture 2 (HC2; Qiagen, Hilden, Germany) or multiplex polymerase chain reaction fluorescence testing (MPFT) methods.Results: During the study period, HPV testing steadily increased, with 643,702 HC2 and 27,641 MPFT HPV tests performed. The mean ages of the tested women were 35.0 years using HC2 and 38.3 years using MPFT. The HC2 HPV-positive rate was 21.7%, significantly higher than 15.7% with MPFT (P < .0001), with bimodal peak incidence in adolescents and women aged 60 to 69 years.Conclusions: Use of HPV testing in cervical screening is increasing in China. HC2 HPV-positive rates around 20% in all age groups from more than 500,000 tested Chinese women are consistent with previous reports from China and significantly higher than published HC2 HPV-positive rates in populations with more widespread cervical screening. MPFT HPV-positive rates were slightly lower in every age group. The high HPV-positive rate likely reflects limited routine cervical screening and high cervical cancer incidence in China. [ABSTRACT FROM AUTHOR]

Abstract: Hexagonal phase NaYF4:Yb3+ 20mol%/Er3+ 1mol% microcrystals that exhibit intense green emission were successfully synthesized via a facile hydrothermal method. The factors including the NaF/Ln (Ln=Y+Yb+Er) molar ratio, pH value of the precursor solution, and the ethylenediaminetetraacetic acid (EDTA)/Ln molar ratio, were well studied in the influences on the crystal structures, morphologies, and sizes of final products. The experimental results indicate that the NaF/Ln ratio and pH value play key roles in crystal structure and morphology of the product. Photoluminescence measurements demonstrate that the relative up-conversion photoluminescence intensity of as-prepared products strongly depends on the crystal structures, crystallization degrees, morphologies, and sizes. [Copyright &y& Elsevier]