Genetic heterogeneity of CTX-M type extended-spectrum ß-lactamase producing Escherichia coli strains from diverse sources in Saudi Arabia

Background: The rise of CTX-M extended spectrum β-lactamase (ESBLs)-producing E. coli in non-human sources is a growing concern of public health. Understanding the extent of public health risk attributed to CTX-M type ESBLs-producing strains from different sources is critical for effective control.Objective: This study focuses on detection and molecular typing of CTX-M type ESBL-producing E. coli isolated from various sources in Taif, Western Saudi Arabia. Material and Methods: A total of 24 E. coli ESBLs-producing isolates from multiple sources were assessed for the presence of CTX-M groups gene by PCR, and subsequently their clonal relatedness by random amplifid of polymorphic DNA (RAPD) analysis. Isolates were selected according to a resistance phenotype consistent with production of ESBL-type beta-lactamase using double disk diffusion method.Results: A CTX-M gene was detected in all 24 isolates. RAPD typing of E. coli isolates bearing CTX-M gene showed 24 patterns verifid into two major clusters (A, B) and three sub-clusters (A1 – A3). Phylogenetic analysis indicating a degree of similarity among clustering isolates from human, sheep and raw milk origins. Identical profie was observed between three isolates obtained from pet bird and chicken

Electrochemically Induced Mesomorphism Switching in a Chlorpromazine Hydrochloride Lyotropic Liquid Crystal

The discovery of electrochemical switching of the Lα phase of chlorpromazine hydrochloride in water is reported. The phase is characterized using polarizing microscopy, X-ray scattering, rheological measurements, and microelectrode voltammetry. Fast, heterogeneous oxidation of the lyotropic liquid crystal is shown to cause a phase change resulting from the disordering of the structural order in a stepwise process. The underlying molecular dynamics is considered to be a cooperative effect of both increasing electrostatic interactions and an unfolding of the monomers from "butterfly"-shaped in the reduced form to planar in the oxidized form

Current Trends in Nanoporous Anodized Alumina Platforms for Biosensing Applications

Pristine aluminum (Al) has received great deal of attention on fabrication of nanoporous anodized alumina (NAA) with arrays of nanosized uniform pores with controllable pore sizes and lengths by the anodization process. There are many applications of NAA in the field of biosensors due to its numerous key factors such as ease of fabrication, high surface area, chemical stability and detection of biomolecules through bioconjugation of active molecules, its rapidness, and real-time monitoring. Herein, we reviewed the recent trends on the fabrication of NAA for high sensitive biosensor platforms like bare sensors, gold coated sensors, multilayer sensors, and microfluidic device supported sensors for the detection of various biomolecules. In addition, we have discussed the future prospectus about the improvement of NAA based biosensors for the detection of biomolecules

Hydrogen and Carbon Nanotubes from Pyrolysis-Catalysis of Waste Plastics: A Review

More than 27 million tonnes of waste plastics are generated in Europe each year representing a considerable potential resource. There has been extensive research into the production of liquid fuels and aromatic chemicals from pyrolysis-catalysis of waste plastics. However, there is less work on the production of hydrogen from waste plastics via pyrolysis coupled with catalytic steam reforming. In this paper, the different reactor designs used for hydrogen production from waste plastics are considered and the influence of different catalysts and process parameters on the yield of hydrogen from different types of waste plastics are reviewed. Waste plastics have also been investigated as a source of hydrocarbons for the generation of carbon nanotubes via the chemical vapour deposition route. The influences on the yield and quality of carbon nanotubes derived from waste plastics are reviewed in relation to the reactor designs used for production, catalyst type used for carbon nanotube growth and the influence of operational parameters

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Reflective interference study of binding nikelions on nitrilotriacetic (nta) nanoporous alumina chips for detections of his-tagged proteins

In this report, the application of a label-free reflectometric interference spectroscopy (RIfS) using nanoporous anodic aluminium oxide (AAO) to study of binding kinetics of nickel ions to self-assembled monolayers (SAMs) of nitrilotriacetic (NTA) chelates is presented. Highly ordered nanoporous AAO fabricated by electrochemical anodization of aluminium foil was used as the RIfS sensing platform. SAM of alkanethiol (C2) terminated with NTA functional group that specifically binds to Ni2+ ions was covalently attached to gold coated AAO surface using simple self-assembly process. The binding of Ni2+ ions to NTA-Au-AAO chip using different concentrations (0.1 mM to 100 mM) was monitored by RIfS spectroscopy in a steady state conditions. Our results show that RIfS optical system using functionalised nanopore AAO arrays is capable of detecting real-time binding and binding kinetics of Ni2+ ions on NTA ligands. This optical method shows a great promise to be used as generic method for studying molecular binding kinetics for other analytes including metal ions, proteins, DNA and antibodies. Furthermore, the approach can be easily translated into a rapid and cost-effective biosensing device for the detection and purification of histidine tagged genetically engineered proteins relevant to proteomics.Tushar Kumeria, Tariq Altalhi and Dusan Losi

Outstanding adsorption performance of graphene-carbon nanotube aerogels for continuous oil removal

Abstract not availableShervin Kabiri, Diana N.H. Tran, Tariq Altalhi, Dusan Losi

Facile and controllable route for nitrogen doping of carbon nanotubes composite membranes by catalyst-free chemical vapour deposition

Abstract not availableMohammed Alsawat, Tariq Altalhi, Abel Santos, Dusan Losi

Carbon nanotubes-nanoporous anodic alumina composite membranes: influence of template on structural, chemical, and transport properties

This work presents the synthesis of carbon nanotubes−nanoporous anodic alumina composite membranes (CNTs−NAAMs) with controllable geometric features by a template-assisted catalyst-free chemical vapor deposition (CVD) approach using a mixture of toluene and ethanol as a carbon precursor. NAAMs templates were prepared by anodization of aluminum substrates in different electrolytes containing sulfuric, oxalic, and phosphoric acids with the aim of establishing the template effect on the CNTs growth. The deposition time during the CVD process was systematically modified to determine the formation mechanism of CNTs inside the pores of NAAMs without using metal catalysts. The structural features, chemical composition, and graphitic structures of the resulting CNTs−NAAMs composites were characterized by different techniques to provide a comprehensive understanding of the effect of the template on the formation of these carbon-based nanostructures. CNTs−NAAMs with inner pore diameters ranging from 15 to 180 nm were used. Our results reveal that the electrolyte type used to prepare NAAMs and the deposition time during the CVD process have a direct impact on the structural, chemical, and graphitic structural features of CNTs−NAAMs. The molecular transport properties of CNTs−NAAMs composite membranes featuring different geometries and chemical compositions were evaluated via the diffusion process of Rose Bengal, a dye model molecule. The obtained results show that the diffusional flux of the dye molecules can be controlled by tuning the inner pore diameter of CNTs deposited inside NAAMs, and the smaller the diameter of the nanotubes the faster the transport of dye molecules is. Our results provide novel insights into the fabrication of different CNTs composite membranes, establishing for the first time the influence of three common types of NAAMs templates on the properties of the resulting CNTs composite membranes. Our study enables the precise engineering of advanced CNTs composite membranes with controlled physical and chemical properties suitable for specific applications.Mohammed Alsawat, Tariq Altalhi, Abel Santos, and Dusan Losi