48 research outputs found
TiO2 nanotubes decorated by silver nanocubes: Extraction of high field emission current density
No full textPositive and Negative Ion Electrospray Tandem Mass Spectrometry (ESI MS/MS) of Boc-Protected Peptides Containing Repeats of L-Ala-γ4Caa/γ4Caa-L-Ala: Differentiation of Some Positional Isomeric Peptides
No full textHigh-resolution electrospray ionization (ESI) quadrupole time-of-flight and ion trap tandem mass spectrometry has been used to distinguish the positional isomers of a new class of N-blocked hybrid peptides containing repeats of the amino acids, L-Ala-γ4Caa (l)/γ4Caa(l)-L-Ala [Caa(l) = Carbo (lyxose) amino acid, derived from D-mannose]. Both MS/MS and MS3 of protonated isomeric peptides produce characteristic fragmentation involving the peptide backbone, Boc-group, and the side-chain. It is interesting to observe that the abundant yn+ ions are formed when the corresponding amide −NH does not participate in the helical structures in solution phase and relatively low abundance yn+ ions resulted when the amide −NH involves in the H-bonding. Thus, it was possible to identify the amide −NH hydrogens that participate in the helical structures through H-bonding in solution phase. Further, negative ion ESI MS/MS has also been found to be useful for differentiating these isomeric peptide acids
Frequencies of hepatitis B and C infections among haemodialysis and peritoneal dialysis patients in Asia-Pacific countries: analysis of registry data
No full textBackground: The impact of dialysis modality on the rates and types of infectious complications has not been well studied. The aim of the present investigation was to evaluate the rates of hepatitis C virus (HCV) and hepatitis B virus (HBV) infections in peritoneal dialysis (PD) and haemodialysis (HD) patients in the Asia-Pacific region. Methods: The study included the most recent period-prevalent data recorded in the national or regional dialysis registries of the 10 Asia-Pacific countries/areas (Australia, New Zealand, Japan, China, Taiwan, Korea, Thailand, Hong Kong, Malaysia and India), where such data were available. Longitudinal data were also available for all incident Australian and New Zealand patients commencing dialysis between 1 April 1995 and 31 December 2005. Rates of HCV and HBV infections were compared by chi-square, Poisson regression and Kaplan–Meier survival analyses, as appropriate. Results: Data were obtained on 201 590 patients (HD 173 788; PD 27 802). HCV seroprevalences ranged between 0.7% and 18.1% across different countries and were generally higher in HD versus PD populations (7.9% ± 5.5% versus 3.0% ± 2.0%, P = 0.01). Seroconversion rates on dialysis were also significantly higher in HD patients (incidence rate ratio PD versus HD 0.33, 95% CI 0.13–0.75). HCV infection was highly predictive of mortality in Japan (relative risk 1.37, 95% CI 1.15–1.62, P = 0.003) and in Australia and New Zealand (adjusted hazards ratio 1.29, 95% CI 1.05–1.58). HBV infection data were limited, but less clearly influenced by dialysis modality. Conclusions: Dialysis modality selection significantly influences the risk of HCV infection experienced by end-stage renal failure patients in the Asia-Pacific region. No such association could be identified for HBV infection.David W. Johnson, Hannah Dent, Qiang Yao, Anders Tranaeus, Chiu-Chin Huang, Dae-Suk Han, Vivekanand Jha, Tao Wang, Yoshindo Kawaguchi and Jiaqi Qian
A green synthesis of isoquinolines using Ru(II)/PEG-400 as homogeneous recyclable catalyst via C-H/N-N bond activation
Get PDF842-849A novel and green synthesis of 1-phenyl isoquinoline derivatives has been developed by using Ru(II)/PEG-400 as homogeneous recyclable catalyst via C-H/N-N bond activation via C-H/N-N functionalization of 1-(diphenylmethylene) hydrazine and aryl substituted acetylenes. In order to realize the proposed protocol, Cu(OAc)2 and AgSbF6 are used as oxidant and additive respectively in PEG-400 biodegradable solvent. This protocol has a simple extraction procedure, uses biodegradable solvent, affords high atom economy, employs a reusable catalytic system, provides wide substrate scope with high yield of product, for the synthesis of isoquinoline derivatives
Molecular characterization of typing and subtyping of Staphylococcal cassette chromosome SCCmec types I to V in methicillin-resistant Staphylococcus aureus from clinical isolates from COVID-19 patients
Get PDFBackground and Objectives: Methicillin resistance is acquired by the bacterium due to mecA gene which codes for penicillin-binding protein (PBP2a) having low affinity for β-lactam antibiotics. mecA gene is located on a mobile genetic element called staphylococcal cassette chromosome mec (SCCmec). SCCmec genomic island comprises two site-specific recombinase genes namely ccrA and ccrB [cassette chromosome recombinase] accountable for mobility. Currently, SCCmec elements are classified into types I, II, III, IV and V based on the nature of the mec and ccr gene complexes and are further classified into subtypes according to variances in their J region DNA. SSCmec type IV has been found in community-acquired isolates with various genetic backgrounds. The present study was undertaken to categorize the types of SCCmec types and subtypes I, II, III, IVa, b, c, d, and V and PVL genes among clinical MRSA isolates from COVID-19 confirmed cases.
Materials and Methods: Based on the Microbiological and Molecular (mecA gene PCR amplification) confirmation of MRSA isolated from 500 MRSA SCCmec clinical samples, 144 cultures were selected for multiplex analysis. The multiplex PCR method developed by Zhang et al. was adapted with some experimental alterations to determine the specific type of these isolates.
Results: Of the total 500 MRSA, 144 MRSA (60 were CA-MRSA and 84 were HA-MRSA) were selected for characterization of novel multiplex PCR assay for SSCmec Types I to V in MRSA. Molecular characterization of multiplex PCR analysis revealed results compare to the phenotypic results. Of the 60 CA-MRSA; in 56 MRSA strains type IVa was found and significantly defined as CA-MRSA while 4 strains showed mixed gens subtypes. Type II, III, IA, and V were present in overall 84 HA-MRSA. Molecular subtyping was significantly correlated to define molecularly as CA-MRSA and HA-MRSA however 15 (10%) strains showed mixed genes which indicates the alarming finding of changing epidemiology of CA-MRSA and HA-MRSA as well.
Conclusion: We have all witnessed of COVID-19 pandemic, and its mortality was mostly associated with co-morbid conditions and secondary infections of MDR pathogens. Rapid detections of causative agents of these superbugs with their changing epidemiology by investing in typing and subtyping clones are obligatory. We have described an assay designed for targeting SSCmec types and subtypes I, II, III, IVa,V according to the current updated SCCmec typing system. Changing patterns of molecular epidemiology has been observed by this newly described assay
ChemInform Abstract: Application Progress of Recent Advances in Some Copper Catalyzed Coupling Reactions
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12/10‐ and 11/13‐Mixed Helices in α/γ‐ and β/γ‐Hybrid Peptides Containing C‐Linked Carbo‐γ‐amino Acids with Alternating α‐ and β‐Amino Acids.
No full textA green synthesis of isoquinolines using Ru(II)/PEG-400 as homogeneous recyclable catalyst via C-H/N-N bond activation
Get PDFA novel and green synthesis of 1-phenyl isoquinoline derivatives has been developed by using Ru(II)/PEG-400 as homogeneous recyclable catalyst via C-H/N-N bond activation via C-H/N-N functionalization of 1-(diphenylmethylene) hydrazine and aryl substituted acetylenes. In order to realize the proposed protocol, Cu(OAc)2 and AgSbF6 are used as oxidant and additive respectively in PEG-400 biodegradable solvent. This protocol has a simple extraction procedure, uses biodegradable solvent, affords high atom economy, employs a reusable catalytic system, provides wide substrate scope with high yield of product, for the synthesis of isoquinoline derivatives
