The antibiotic batumin, produced by Pseudomonas batumici, has been shown to be highly active against 123 type and reference strains and clinical isolates of 30 Staphylococcus species (including MRSA and small colony v...The antibiotic batumin, produced by Pseudomonas batumici, has been shown to be highly active against 123 type and reference strains and clinical isolates of 30 Staphylococcus species (including MRSA and small colony variants—(SSCVs) of S. aureus, S. epidermidis and S. haemolyticus). Batumin activity against these bacteria did not depend on the species, origin or resistance to other antibiotics and its MIC was 0.0625 - 0.5 mg/ml. Batumin influence on biofilm formation was studied in clinical isolates of S. aureus, S. epidermidis and S. intermedius. Addition of batumin at a concentration of half of the MIC in the broth, i.e. 0.125 μg/ml, decreased the biofilm of 16 out of 20 S. aureus strains to varying degrees. Batumin was more effective against Staphylococcus strains with strong biofilm formation. Using atomic-force microscopy, it could be shown that batumin reduced the number of S. aureus ATCC 25923 adherent cells more than fourfold. The adherent cells of staphylococci were visualized as monolayers of separate islets. A detailed study of the surface of bacterial cells treated with batumin allowed to establish significant reduction of their roughness values. Observed values were typical for planktonic S. aureus cells. The obtained data explain one of the mechanisms of the antimicrobial activity of batumin, which is based оn preventing the formation of S. aureus biofilm. As such, batumin could be considered as an agent offering opportunities for the treatment of staphylococcal biofilm-associated infections.展开更多
Image-based rock typing(IBRT)is an effective way to understand the pore scale heterogeneity of the reservoir samples.IBRT is aimed at segmenting a rock sample's image into different regions where each region repre...Image-based rock typing(IBRT)is an effective way to understand the pore scale heterogeneity of the reservoir samples.IBRT is aimed at segmenting a rock sample's image into different regions where each region represents a homogeneous porous medium,also known as rock type.Currently,the phase-field rock typing method has attracted more attention due to its impressive performance in classifying the heterogeneous rock images with highly irregular pore structures.In this paper,a modified specific surface CV(SSCV)model is proposed to realize the IBRT.In the SSCV model,the specific surface of a pixel is calculated within a given size neighborhood to distinguish different rock types,and the iterative convolution-thresholding method(ICTM)is applied as the classifier.Compared to the LHFCV method,an existing phase-field rock typing method,the proposed SSCV is capable of processing the images with more than two rock types and can be solved by ICTM which has higher computational efficiency.The proposed SSCV method has demonstrated remarkable performance in the segmentation of various images of both synthetic and natural rock samples.展开更多
文摘The antibiotic batumin, produced by Pseudomonas batumici, has been shown to be highly active against 123 type and reference strains and clinical isolates of 30 Staphylococcus species (including MRSA and small colony variants—(SSCVs) of S. aureus, S. epidermidis and S. haemolyticus). Batumin activity against these bacteria did not depend on the species, origin or resistance to other antibiotics and its MIC was 0.0625 - 0.5 mg/ml. Batumin influence on biofilm formation was studied in clinical isolates of S. aureus, S. epidermidis and S. intermedius. Addition of batumin at a concentration of half of the MIC in the broth, i.e. 0.125 μg/ml, decreased the biofilm of 16 out of 20 S. aureus strains to varying degrees. Batumin was more effective against Staphylococcus strains with strong biofilm formation. Using atomic-force microscopy, it could be shown that batumin reduced the number of S. aureus ATCC 25923 adherent cells more than fourfold. The adherent cells of staphylococci were visualized as monolayers of separate islets. A detailed study of the surface of bacterial cells treated with batumin allowed to establish significant reduction of their roughness values. Observed values were typical for planktonic S. aureus cells. The obtained data explain one of the mechanisms of the antimicrobial activity of batumin, which is based оn preventing the formation of S. aureus biofilm. As such, batumin could be considered as an agent offering opportunities for the treatment of staphylococcal biofilm-associated infections.
基金supported by the Hong Kong Polytechnic University(Grant Nos.G-UAEY,4-ZZLS)the CAS AMSS-PolyU Joint Laboratory of Applied Mathematics(Grant No.1-ZVA8)+1 种基金the King Abdullah University of Science and Technology(Grant Nos.BAS/1/1351-01,URF/1/4074-01,URF/1/3769-01)the Maths4DL program(Grant No.EP/V026259/1).
文摘Image-based rock typing(IBRT)is an effective way to understand the pore scale heterogeneity of the reservoir samples.IBRT is aimed at segmenting a rock sample's image into different regions where each region represents a homogeneous porous medium,also known as rock type.Currently,the phase-field rock typing method has attracted more attention due to its impressive performance in classifying the heterogeneous rock images with highly irregular pore structures.In this paper,a modified specific surface CV(SSCV)model is proposed to realize the IBRT.In the SSCV model,the specific surface of a pixel is calculated within a given size neighborhood to distinguish different rock types,and the iterative convolution-thresholding method(ICTM)is applied as the classifier.Compared to the LHFCV method,an existing phase-field rock typing method,the proposed SSCV is capable of processing the images with more than two rock types and can be solved by ICTM which has higher computational efficiency.The proposed SSCV method has demonstrated remarkable performance in the segmentation of various images of both synthetic and natural rock samples.
