MEKKAOUI FARIDA, Menkad S.
CLASSES OF OPERATORS ASSOCIATED WITH (f,g)-ALUTHGE TRANSFORMS. Asia Pacific Journal of Mathematics [Internet]. 2025;12 (57).
Publisher's VersionAbstract
Let T ∈ B(H) be a bounded linear operator on a Hilbert space H with the polar decomposition T =U|T|. The(f,g)-Aluthge transform of the operator T, denoted by ∆f,g(T), is defined as ∆f,g(T) = f(|T|)Ug(|T|), wheref andg botharenon-negativecontinuousfunctionson[0,∞[suchthatf(x)g(x) = x, for all x ≥ 0. In this paper, firstly, we investigate the relationship between this transform and several classes of operators as quasi-normal, normal, positive, nilpotent and closed range operators. Secondly, we show that under some conditions the (f,g)-Aluthge transform possesses the polar decomposition. Lastly, we provide a characterization of binormal operators from the viewpoint of the polar decomposition and the (f, g)-Aluthge transform. 2020 Mathematics Subject Classification. 47A05; 47B49. Key words and phrases. (f,g)-Aluthge transform; quasinormal operato; Polar decomposition; binormal operators.
MEKKAOUI FARIDA, Menkad S.
CLASSES OF OPERATORS ASSOCIATED WITH (f,g)-ALUTHGE TRANSFORMS. Asia Pacific Journal of Mathematics [Internet]. 2025;12 (57).
Publisher's VersionAbstract
Let T ∈ B(H) be a bounded linear operator on a Hilbert space H with the polar decomposition T =U|T|. The(f,g)-Aluthge transform of the operator T, denoted by ∆f,g(T), is defined as ∆f,g(T) = f(|T|)Ug(|T|), wheref andg botharenon-negativecontinuousfunctionson[0,∞[suchthatf(x)g(x) = x, for all x ≥ 0. In this paper, firstly, we investigate the relationship between this transform and several classes of operators as quasi-normal, normal, positive, nilpotent and closed range operators. Secondly, we show that under some conditions the (f,g)-Aluthge transform possesses the polar decomposition. Lastly, we provide a characterization of binormal operators from the viewpoint of the polar decomposition and the (f, g)-Aluthge transform. 2020 Mathematics Subject Classification. 47A05; 47B49. Key words and phrases. (f,g)-Aluthge transform; quasinormal operato; Polar decomposition; binormal operators.
Bouali A, Bendjama E, Cherak Z, Mennaai M, Kassah-Laouar A, Rolain J-M, Loucif L.
Distribution of carbapenemase-producing and colistin resistant Acinetobacter baumannii isolates in Batna hospitals, Algeria. BMC Infectious Diseases [Internet]. 2025;25.
Publisher's VersionAbstract
Objective The aim of this study was to investigate the distribution and genetic determinants of carbapenemase production and colistin resistance among Acinetobacter baumannii isolates recovered from three health care facilities in the city of Batna, Algeria.
Methods A prospective study was conducted between 2021 and 2022 on 46 Acinetobacter baumannii clinical isolates, which were collected and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility testing was performed using the disk diffusion method and colistin minimum inhibitory concentrations (MICs) were determined by broth microdilution method. Carbapenemase and colistin resist ance determinants were detected by qPCR.
Results The 46 clinical isolates were mainly from the intensive care unit (52.17%) and the burns unit (17.39%). The strains were collected primarily from pus samples (34.78%) and blood samples (17.39%). Eleven strains were classified as colistin-resistant, with MICs ranging from 4 to 128 μg/mL. The blaOXA-24 gene was detected in 63.04% of the isolates, followed by the blaOXA-23 gene (43.47%). Nine strains were positive for both blaOXA-23-like and blaOXA-24-like genes. The blaNDM gene was detected in eight isolates (17.39%), including two which co-expressed a blaOXA-24 gene. In contrast, all strains were negative for the plasmid-mediated colistin resistance mcr-1 to mcr-5 and mcr-8.
Conclusion Here, we report a high prevalence of carbapenemases-producing A. baumannii isolates in Batna hospi tals. Notably, this study is the first to identify A. baumannii isolates co-producing OXA-24 and NDM carbapenemases and to report the first detection of colistin-resistant A. baumannii co-producing OXA-24 and OXA-23 carbapenemases from a patient in Algeria.
Keywords Acinetobacter baumannii, blaOXA-23, blaOXA-24, blaNDM, Algeri
Bouali A, Bendjama E, Cherak Z, Mennaai M, Kassah-Laouar A, Rolain J-M, Loucif L.
Distribution of carbapenemase-producing and colistin resistant Acinetobacter baumannii isolates in Batna hospitals, Algeria. BMC Infectious Diseases [Internet]. 2025;25.
Publisher's VersionAbstract
Objective The aim of this study was to investigate the distribution and genetic determinants of carbapenemase production and colistin resistance among Acinetobacter baumannii isolates recovered from three health care facilities in the city of Batna, Algeria.
Methods A prospective study was conducted between 2021 and 2022 on 46 Acinetobacter baumannii clinical isolates, which were collected and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility testing was performed using the disk diffusion method and colistin minimum inhibitory concentrations (MICs) were determined by broth microdilution method. Carbapenemase and colistin resist ance determinants were detected by qPCR.
Results The 46 clinical isolates were mainly from the intensive care unit (52.17%) and the burns unit (17.39%). The strains were collected primarily from pus samples (34.78%) and blood samples (17.39%). Eleven strains were classified as colistin-resistant, with MICs ranging from 4 to 128 μg/mL. The blaOXA-24 gene was detected in 63.04% of the isolates, followed by the blaOXA-23 gene (43.47%). Nine strains were positive for both blaOXA-23-like and blaOXA-24-like genes. The blaNDM gene was detected in eight isolates (17.39%), including two which co-expressed a blaOXA-24 gene. In contrast, all strains were negative for the plasmid-mediated colistin resistance mcr-1 to mcr-5 and mcr-8.
Conclusion Here, we report a high prevalence of carbapenemases-producing A. baumannii isolates in Batna hospi tals. Notably, this study is the first to identify A. baumannii isolates co-producing OXA-24 and NDM carbapenemases and to report the first detection of colistin-resistant A. baumannii co-producing OXA-24 and OXA-23 carbapenemases from a patient in Algeria.
Keywords Acinetobacter baumannii, blaOXA-23, blaOXA-24, blaNDM, Algeri
Bouali A, Bendjama E, Cherak Z, Mennaai M, Kassah-Laouar A, Rolain J-M, Loucif L.
Distribution of carbapenemase-producing and colistin resistant Acinetobacter baumannii isolates in Batna hospitals, Algeria. BMC Infectious Diseases [Internet]. 2025;25.
Publisher's VersionAbstract
Objective The aim of this study was to investigate the distribution and genetic determinants of carbapenemase production and colistin resistance among Acinetobacter baumannii isolates recovered from three health care facilities in the city of Batna, Algeria.
Methods A prospective study was conducted between 2021 and 2022 on 46 Acinetobacter baumannii clinical isolates, which were collected and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility testing was performed using the disk diffusion method and colistin minimum inhibitory concentrations (MICs) were determined by broth microdilution method. Carbapenemase and colistin resist ance determinants were detected by qPCR.
Results The 46 clinical isolates were mainly from the intensive care unit (52.17%) and the burns unit (17.39%). The strains were collected primarily from pus samples (34.78%) and blood samples (17.39%). Eleven strains were classified as colistin-resistant, with MICs ranging from 4 to 128 μg/mL. The blaOXA-24 gene was detected in 63.04% of the isolates, followed by the blaOXA-23 gene (43.47%). Nine strains were positive for both blaOXA-23-like and blaOXA-24-like genes. The blaNDM gene was detected in eight isolates (17.39%), including two which co-expressed a blaOXA-24 gene. In contrast, all strains were negative for the plasmid-mediated colistin resistance mcr-1 to mcr-5 and mcr-8.
Conclusion Here, we report a high prevalence of carbapenemases-producing A. baumannii isolates in Batna hospi tals. Notably, this study is the first to identify A. baumannii isolates co-producing OXA-24 and NDM carbapenemases and to report the first detection of colistin-resistant A. baumannii co-producing OXA-24 and OXA-23 carbapenemases from a patient in Algeria.
Keywords Acinetobacter baumannii, blaOXA-23, blaOXA-24, blaNDM, Algeri
Bouali A, Bendjama E, Cherak Z, Mennaai M, Kassah-Laouar A, Rolain J-M, Loucif L.
Distribution of carbapenemase-producing and colistin resistant Acinetobacter baumannii isolates in Batna hospitals, Algeria. BMC Infectious Diseases [Internet]. 2025;25.
Publisher's VersionAbstract
Objective The aim of this study was to investigate the distribution and genetic determinants of carbapenemase production and colistin resistance among Acinetobacter baumannii isolates recovered from three health care facilities in the city of Batna, Algeria.
Methods A prospective study was conducted between 2021 and 2022 on 46 Acinetobacter baumannii clinical isolates, which were collected and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility testing was performed using the disk diffusion method and colistin minimum inhibitory concentrations (MICs) were determined by broth microdilution method. Carbapenemase and colistin resist ance determinants were detected by qPCR.
Results The 46 clinical isolates were mainly from the intensive care unit (52.17%) and the burns unit (17.39%). The strains were collected primarily from pus samples (34.78%) and blood samples (17.39%). Eleven strains were classified as colistin-resistant, with MICs ranging from 4 to 128 μg/mL. The blaOXA-24 gene was detected in 63.04% of the isolates, followed by the blaOXA-23 gene (43.47%). Nine strains were positive for both blaOXA-23-like and blaOXA-24-like genes. The blaNDM gene was detected in eight isolates (17.39%), including two which co-expressed a blaOXA-24 gene. In contrast, all strains were negative for the plasmid-mediated colistin resistance mcr-1 to mcr-5 and mcr-8.
Conclusion Here, we report a high prevalence of carbapenemases-producing A. baumannii isolates in Batna hospi tals. Notably, this study is the first to identify A. baumannii isolates co-producing OXA-24 and NDM carbapenemases and to report the first detection of colistin-resistant A. baumannii co-producing OXA-24 and OXA-23 carbapenemases from a patient in Algeria.
Keywords Acinetobacter baumannii, blaOXA-23, blaOXA-24, blaNDM, Algeri
Bouali A, Bendjama E, Cherak Z, Mennaai M, Kassah-Laouar A, Rolain J-M, Loucif L.
Distribution of carbapenemase-producing and colistin resistant Acinetobacter baumannii isolates in Batna hospitals, Algeria. BMC Infectious Diseases [Internet]. 2025;25.
Publisher's VersionAbstract
Objective The aim of this study was to investigate the distribution and genetic determinants of carbapenemase production and colistin resistance among Acinetobacter baumannii isolates recovered from three health care facilities in the city of Batna, Algeria.
Methods A prospective study was conducted between 2021 and 2022 on 46 Acinetobacter baumannii clinical isolates, which were collected and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility testing was performed using the disk diffusion method and colistin minimum inhibitory concentrations (MICs) were determined by broth microdilution method. Carbapenemase and colistin resist ance determinants were detected by qPCR.
Results The 46 clinical isolates were mainly from the intensive care unit (52.17%) and the burns unit (17.39%). The strains were collected primarily from pus samples (34.78%) and blood samples (17.39%). Eleven strains were classified as colistin-resistant, with MICs ranging from 4 to 128 μg/mL. The blaOXA-24 gene was detected in 63.04% of the isolates, followed by the blaOXA-23 gene (43.47%). Nine strains were positive for both blaOXA-23-like and blaOXA-24-like genes. The blaNDM gene was detected in eight isolates (17.39%), including two which co-expressed a blaOXA-24 gene. In contrast, all strains were negative for the plasmid-mediated colistin resistance mcr-1 to mcr-5 and mcr-8.
Conclusion Here, we report a high prevalence of carbapenemases-producing A. baumannii isolates in Batna hospi tals. Notably, this study is the first to identify A. baumannii isolates co-producing OXA-24 and NDM carbapenemases and to report the first detection of colistin-resistant A. baumannii co-producing OXA-24 and OXA-23 carbapenemases from a patient in Algeria.
Keywords Acinetobacter baumannii, blaOXA-23, blaOXA-24, blaNDM, Algeri
Bouali A, Bendjama E, Cherak Z, Mennaai M, Kassah-Laouar A, Rolain J-M, Loucif L.
Distribution of carbapenemase-producing and colistin resistant Acinetobacter baumannii isolates in Batna hospitals, Algeria. BMC Infectious Diseases [Internet]. 2025;25.
Publisher's VersionAbstract
Objective The aim of this study was to investigate the distribution and genetic determinants of carbapenemase production and colistin resistance among Acinetobacter baumannii isolates recovered from three health care facilities in the city of Batna, Algeria.
Methods A prospective study was conducted between 2021 and 2022 on 46 Acinetobacter baumannii clinical isolates, which were collected and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility testing was performed using the disk diffusion method and colistin minimum inhibitory concentrations (MICs) were determined by broth microdilution method. Carbapenemase and colistin resist ance determinants were detected by qPCR.
Results The 46 clinical isolates were mainly from the intensive care unit (52.17%) and the burns unit (17.39%). The strains were collected primarily from pus samples (34.78%) and blood samples (17.39%). Eleven strains were classified as colistin-resistant, with MICs ranging from 4 to 128 μg/mL. The blaOXA-24 gene was detected in 63.04% of the isolates, followed by the blaOXA-23 gene (43.47%). Nine strains were positive for both blaOXA-23-like and blaOXA-24-like genes. The blaNDM gene was detected in eight isolates (17.39%), including two which co-expressed a blaOXA-24 gene. In contrast, all strains were negative for the plasmid-mediated colistin resistance mcr-1 to mcr-5 and mcr-8.
Conclusion Here, we report a high prevalence of carbapenemases-producing A. baumannii isolates in Batna hospi tals. Notably, this study is the first to identify A. baumannii isolates co-producing OXA-24 and NDM carbapenemases and to report the first detection of colistin-resistant A. baumannii co-producing OXA-24 and OXA-23 carbapenemases from a patient in Algeria.
Keywords Acinetobacter baumannii, blaOXA-23, blaOXA-24, blaNDM, Algeri
Bouali A, Bendjama E, Cherak Z, Mennaai M, Kassah-Laouar A, Rolain J-M, Loucif L.
Distribution of carbapenemase-producing and colistin resistant Acinetobacter baumannii isolates in Batna hospitals, Algeria. BMC Infectious Diseases [Internet]. 2025;25.
Publisher's VersionAbstract
Objective The aim of this study was to investigate the distribution and genetic determinants of carbapenemase production and colistin resistance among Acinetobacter baumannii isolates recovered from three health care facilities in the city of Batna, Algeria.
Methods A prospective study was conducted between 2021 and 2022 on 46 Acinetobacter baumannii clinical isolates, which were collected and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility testing was performed using the disk diffusion method and colistin minimum inhibitory concentrations (MICs) were determined by broth microdilution method. Carbapenemase and colistin resist ance determinants were detected by qPCR.
Results The 46 clinical isolates were mainly from the intensive care unit (52.17%) and the burns unit (17.39%). The strains were collected primarily from pus samples (34.78%) and blood samples (17.39%). Eleven strains were classified as colistin-resistant, with MICs ranging from 4 to 128 μg/mL. The blaOXA-24 gene was detected in 63.04% of the isolates, followed by the blaOXA-23 gene (43.47%). Nine strains were positive for both blaOXA-23-like and blaOXA-24-like genes. The blaNDM gene was detected in eight isolates (17.39%), including two which co-expressed a blaOXA-24 gene. In contrast, all strains were negative for the plasmid-mediated colistin resistance mcr-1 to mcr-5 and mcr-8.
Conclusion Here, we report a high prevalence of carbapenemases-producing A. baumannii isolates in Batna hospi tals. Notably, this study is the first to identify A. baumannii isolates co-producing OXA-24 and NDM carbapenemases and to report the first detection of colistin-resistant A. baumannii co-producing OXA-24 and OXA-23 carbapenemases from a patient in Algeria.
Keywords Acinetobacter baumannii, blaOXA-23, blaOXA-24, blaNDM, Algeri
Nezzar S, Kada M, MENNOUNI ABDELAZIZ.
New findings and improvements regarding the robustness of descriptor systems. Nonlinear Studies (NS) [Internet]. 2025;32 (2).
Publisher's VersionAbstract
This study defines and analyzes the stability radii of stochastic descriptor systems. We utilize generalized Lyapunov
techniques to establish necessary and sufficient conditions for exponential stability. Additionally, the paper aims
to explore robust stability by characterizing the stability radius through generalized Lyapunov equations. To the best of our knowledge, this research is the first to investigate robust stability using the infinite-dimensional
generalized Lyapunov equation.
Nezzar S, Kada M, MENNOUNI ABDELAZIZ.
New findings and improvements regarding the robustness of descriptor systems. Nonlinear Studies (NS) [Internet]. 2025;32 (2).
Publisher's VersionAbstract
This study defines and analyzes the stability radii of stochastic descriptor systems. We utilize generalized Lyapunov
techniques to establish necessary and sufficient conditions for exponential stability. Additionally, the paper aims
to explore robust stability by characterizing the stability radius through generalized Lyapunov equations. To the best of our knowledge, this research is the first to investigate robust stability using the infinite-dimensional
generalized Lyapunov equation.