BackgroundDespite the large number of drug-resistant tuberculosis (TB) cases in China, few studies have comprehensively analyzed the drug resistance-associated gene mutations and genotypes in relation to the clinical characteristics of M. tuberculosis (Mtb) isolates.Methodology/Principal FindingsWe thus analyzed the phenotypic and genotypic drug resistance profiles of 115 Mtb clinical isolates recovered from a tuberculosis referral hospital in Beijing, China. We also performed genotyping by 28 loci MIRU-VNTR analysis. Socio-demographic and clinical data were retrieved from medical records and analyzed. In total, 78 types of mutations (including 42 previously reported and 36 newly identified ones) were identified in 115 Mtb clinical isolates. There was significant correlation between phenotypic and genotypic drug resistance rates for first-line anti-TB drugs (P<0.001). Genotyping revealed 101 MIRU-VNTR types, with 20 isolates (17.4%) being clustered and 95 isolates (82.6%) having unique genotypes. Higher proportion of re-treatment cases was observed among patients with clustered isolates than those with unique MIRU-VNTR genotypes (75.0% vs. 41.1%). Moreover, clinical epidemiological links were identified among patients infected by Mtb strains belonging to the same clusters, suggesting a potential of transmission among patients.Conclusions/SignificanceOur study provided information on novel potential drug resistance-associated mutations in Mtb. In addition, the genotyping data from our study suggested that enforcement of the implementation of genotyping in diagnostic routines would provide important information for better monitor and control of TB transmission.

A 2 D CFD model was established to simulate sawdust gasification in an entrained flow gasifier using Ansys Fluent software. Syngas composition, syngas yield and syngas LHV were evaluated. The simulated syngas compositions were in agreement with the experiment results. The relative errors of syngas yield and LHV varied in the ranges of 2-15% and 1-9%, respectively. The results showed that the numerical model established in this study can be applied to simulate biomass gasification in entrained flow gasifier.

A new wide band k-distribution model has been developed and used to investigate infrared radiation signatures of liquid rocket plume in some detectors’ working spectrum regions, in which the temperature and the gas molar concentration fields are solved using engineering empirical formulations. Based on the line parameters in HITEMP database, absorption coefficient variables of water vapor and carbon dioxide corresponding to 12-point Gauss-Lobatto quadrature points are derived and expressed as a simple formulation. The absorption coefficient variables of mixture are obtained by summing the absorption coefficient variables of individual gas species under the hypothesis that the k-distributions are statistically uncorrelated. Its validity for the numerical prediction of liquid rocket plume radiation is verified by comparison with line-by-line approach (LBL). Compared with line-by-line calculations, the maximum relative errors of the new band model are less than 10 % in the detectors’ working spectrum regions, while the computational time of the new band model is less than 1/1000 of LBL. The effects of fly parameter on infrared radiation signatures of liquid rocket plume are studied using the new model. The results showed that the integral radiation intensities of liquid rocket plume increase with the nozzle exit temperature, Mach number and the ratio of nozzle exit pressure to atmospheric pressure. The radiation intensity variation trend for liquid rocket plume with altitude is different for different detectors’ working spectrum regions.

In the present study, we use direct numerical simulation to investigate the density-driven convection in a two-dimensional anisotropic heterogeneous porous media associated with significant laminated formation. At first, the heterogeneous porous media are randomly generated to represent laminated structure, in which the horizontal correlation length of permeability field is much longer than the vertical counterpart. Then, a highly accurate pseudo-spectral method and compact finite difference scheme with higher order of accuracy are employed to numerically reproduce the convection flow in the laminated porous media. The results show that the laminated structures restrict interactions among the downward plumes of heavier fluid. The plumes tend to descend more straightly in a laminated porous medium associated with a slower growth rate. As a result, the laminated distribution of permeability is considered having an inhibiting effect on the convection flow.