Preparation, spectroscopic, thermal and molecular docking studies of covid-19 protease on the manganese(II), iron(III), chromium(III) and cobalt(II) creatinine complexes

ABSTRACT. Creatinine biomolecule has three different coordination modes through the (exocyclic O(5) and ring N(1)), (imine N(2) and ring N(1)) or as monodentate ligand via exocyclic O(1)). The FTIR and electronic spectra of the synthesized manganese(II), iron(III), chromium(III), and cobalt(II) complexes consistent with the coordinated behavioral derived from the structural analyses. Thermogravimetric data agree with the stoichiometry and proposed formulas [Mn(C4H7N3O)2(Cl)2]4H2O, [Fe(C4H7N3O)2(Cl)2]Cl.6H2O, [Cr(C4H7N3O)2(Cl)2]Cl.6H2O, and [Co(C4H7N3O)2(Cl)2]6H2O. Four new transition metal complexes derived from the reaction of creatinine chelate and metal salt (MnCl2.4H2O, FeCl3.6H2O, CrCl3.6H2O, and CoCl2.6H2O), were prepared with 1:2 (metal: ligand) stoichiometry, isolated and well characterized by a different spectral and analytical techniques including FTIR, UV/Vis, magnetic susceptibility, molar conductance, elemental analysis, and TGA/DrTGA/DTA. The solid complexes were formed with the binding of the creatinine ligand through exocyclic O(5) and ring N(1) and presented as an octahedral geometry. In addition molecular docking calculations have been performed between complexes of manganese(II), iron(III), chromium(III) and cobalt(II) with creatinine biomolecule ligand with the Covid-19 protease (6LU7) to determine the best binding site and its inhibitory effect.                     KEY WORDS: Creatinine, Coordination, Transition metals, TGA/DTA, Octahedral geometry   Bull. Chem. Soc. Ethiop. 2021, 35(2), 399-412. DOI: https://dx.doi.org/10.4314/bcse.v35i2.1

Synthesis, characterization, thermal analysis and biological study of new thiophene derivative containing o-aminobenzoic acid ligand and its Mn(II), Cu(II) and Co(II) metal complexes

New ligand containing 2-(2,4-dioxo-4-thiophen-2-yl-butyrylamino)-benzoic acid (HL) merged moiety was synthesized and characterized by FT-IR, elemental analyses, mass spectra and 1H-NMR spectral. In the present study, the attempts were carried to form complexes of HL ligand with some transition metal ions (MnII, CuII and CoII) of well-defined at the (1:1) ratio of the components in the dimethyl sulfoxide (DMSO) solvent. All complexes have been studied by FTIR spectra, elemental analyses, thermal analysis, molar conductivity, electronic spectra and magnetic moment. The HL ligand produced as a bidentate chelate with interactive metal ions. All the results suggested octahedral geometry to complexes and have the formulae [M(HL)(Cl)2(H2O)2].nH2O where M = Mn(II), Cu(II) and Co(II). The IR spectra of the complexes were assigned and compared with the data in literature. The kinetic and thermodynamic results such as E*, ΔH*, ΔS* and ΔG* were calculated based o the TGA/DTG curves using Coats and Redfern and Horowitz and Metzger approximation methods. Furthermore, the resultant complexes were evaluated for the anti-bacterial and anti-fungal potential.                     KEY WORDS: 2-(2,4-Dioxo-4-thiophen-2-yl-butyrylamino)-benzoic acid, Transition metal complexes, FTIR, TGA, Antimicrobial test   Bull. Chem. Soc. Ethiop. 2021, 35(1), 129-140. DOI: https://dx.doi.org/10.4314/bcse.v35i1.1

Design and Development of Defect Rich Titania Nanostructure for Efficient Electrocatalyst for Hydrogen Evolution Reaction in an Acidic Electrolyte

Cost-effective, efficient and stable electrocatalyst for water splitting in the acidic electrolyte medium has been developed. The acidic electrolyte could be a support for the high purity hydrogen production via water splitting. Accordingly, we have prepared the defect-rich titania nanostructure via electrochemical anodization and cathodization routes using the titanium plate, which showed highly effective and durable electrocatalyst of hydrogen evolution reaction (HER) in an acidic medium. This hybrid compound showed a low onset potential of −0.17 V for HER with a current density of −150 mA cm−2 in 1 M H2SO4. Moreover, the stability test has been performed with the defect-rich titania nanostructure as cathode for 6 h in the two electrodes system. © 2021 The Author(s).The authors extend their appreciation to the Deanship of Scientific Research, King Saud University for funding this work through Research Group no RG-1441-043 and funded by the Taif University Researchers Supporting Project number (TURSP-2020/04), Taif University, Taif, Saudi Arabia. One of the author Dr G. Murugadoss would like to thank Chancellor, President and Vice Chancellor, Sathyabama Institute of Science and Technology, Chennai for providing lab facilities and encouragement

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

Synthesis of well-organised carbon nanotube membranes from non-degradable plastic bags with tuneable molecular transport: towards nanotechnological recycling

This study presents a nanotechnological approach to convert commercially available and non-degradable grocery plastic bags into well-organised carbon nanotube membranes with tuneable molecular transport properties. In this nanotechnological process, plastic bags are used as a carbon source while carbon nanotubes (CNTs) are produced by a catalyst/solvent-free chemical vapour deposition (CVD) approach. Furthermore, CNTs are grown inside nanoporous anodic alumina membranes (NAAMs) featuring hexagonally arranged nanopores, which enable the control over the nanotubes' organisation and geometry. The transport performance of the resulting CNTs-NAAMs is tested by several dye molecules with positive, negative and neutral charge. These results demonstrate the ability of these membranes to selectively tune molecular transport as a function of the interaction between molecules and inner surface of CNTs. This study proves that an environmentally non-degradable wastematerial as commercial plastic bags can be directly used to produce such sophisticated nanodevices as CNTs membranes. © 2013 Elsevier Ltd. All rights reserved.Tariq Altalhi, Tushar Kumeria, Abel Santos, 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