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The variogram method is used to investigate the effect of non-stationarity, heterogeneity, scale-related parameters and anisotropy on roughness quantification of a natural rock joint of size 1 m × 1 m. The methodology quantifies two parameters to capture the stationary roughness. The effect of the non-stationarity of the used profiles was found to be negligible on the computed fractal parameters. Calculated fractal parameter values reflected significant heterogeneity on one part of the roughness surface compared to the rest of the surface studied in the paper. Effect of joint size was found to be negligible on the calculated fractal parameter values. The authors believe that the controversial findings appear in the literature on scale effects have resulted from roughness heterogeneity, which has not been investigated in detail in the literature in quantifying roughness. Rock discontinuity surface showed major anisotropy with respect to roughness. Roughness in the direction along the axis of ridges and troughs (X-direction) of the joint surface was found to be significantly less compared to that in the direction perpendicular to the direction of axis of ridges and troughs. Thus, it agreed with the intuition that the discontinuity resulted from a shear fracture with the main shearing direction approximately parallel to the X direction. [ABSTRACT FROM AUTHOR]

Tuberculosis caused by Mycobacterium tuberculosis remains a major global health concern; M. tuberculosis drug resistance and persistence further fueled the situation. Nutrient supportive therapy was intensively pursued to complement the conventional treatment, as well as their synergy with current antibiotics. To explore whether l-alanine can synergize with fluoroquinolones against M. tuberculosis, M. smegmatis was used as a surrogate in this study. We found that l-alanine can boost the bactericidal efficacy of fluoroquinolones, increasing the production of intracellular reactive oxygen species. This effect is very significant for persisters. Accelerated tricarboxylic acid cycle and/or nucleotide metabolism were observed after the addition of l-alanine. M. smegmatis MSMEG2660 is a homolog of the alanine dehydrogenase (Rv2780, MSMEG2659) negative regulator Rv2779c and involved in the l-alanine potentiation of fluoroquinolone via funneling more alanine into tricarboxylic acid. Deletion mutant of the MSMEG2660 (∆Ms2660) became more susceptible, and more readily revived from persistence. We firstly found that l-alanine can synergize with fluoroquinolones against Mycobacterium, especially the persisters via promoting metabolism. This will inspire new avenue to eliminate Mycobacterium persisters. [ABSTRACT FROM AUTHOR]

Bacterial toxin-antitoxin (TA) systems are emerging important regulators of multiple cellular physiological events and candidates for novel antibiotic targets. To explore the role of Mycobacterium tuberculosis function, unknown toxin gene Rv2872 was heterologously expressed in Mycobacterium smegmatis (MS_Rv2872). Upon induction, MS_Rv2872 phenotype differed significantly from the control, such as increased vancomycin resistance, retarded growth, cell wall, and biofilm structure. This phenotype change might result from the RNase activity of Rv2872 as purified Rv2872 toxin protein can cleave the products of several key genes involved in abovementioned phenotypes. In summary, toxin Rv2872 was firstly reported to be a endonuclease involved in antibiotic stress responses, cell wall structure, and biofilm development. [ABSTRACT FROM AUTHOR]

A 15-layer composite plate was developed. The microstructure and mechanical properties were characterized by scanning electron microscopy, Vickers microhardness, tensile, and bending tests. Particularly, the effects of hot-rolling at different rolling temperatures of 1130, 1180, 1250, and 1300 °C on the microstructure and mechanical properties of the 2Cr13/316L/9Cr18MoV composite plates were investigated in detail. The results indicated that, with the increase in the rolling temperature, the tensile strength was first decreased and then slightly increased by the coarsening of grains and the increase in the ferrite content in the 2Cr13 layers. The highest tensile elongation of 12.5% and tensile strength of 958.1 MPa were obtained for the composite plate manufactured with the rolling temperature of 1180 °C. The 2Cr13/316L/9Cr18MoV composite plates with rolling temperatures of 1130 and 1180 °C obtained by hot-rolling processes withstood larger bending deformations, showing only local cracks after the bending process because of their strong combined interfaces. However, during the bending to 130° of specimens fabricated with the rolling temperature of 1250 and 1300 °C, the specimens experienced direct fracture at very low bending displacements. [ABSTRACT FROM AUTHOR]