Solvent free synthesis of hydrazine carbothioamide derivatives as a precursor in the preparation of new mononuclear Mn(II), Cu(II), and Zn(II) complexes: Spectroscopic characterizations

ABSTRACT. Over the last few years considerable attention has been devoted to the study of Schiff base complexes of metal(II) containing nitrogen, oxygen and sulfur donor ligands due to their diverse biological activities. Therefore, the Schiff base thiosemicarbazone derivatives of 2-(2-hydroxy-3-methoxybenzylidene) hydrazine carbothioamide (HL1) and 2-(4-bromo-2-hydroxy-3-methoxybenzylidene) hydrazine carbothioamide (HL2) were synthesized with solvent free technique using silica gel as material support for the reaction. The structures of the precursor’s organic products confirmed with their 1H, 13C NMR, IR and microanalysis data. Six new manganese(II), copper(II), and zinc(II) complexes of HL1 and HL2 2-(2-hydroxy-3-methoxybenzylidene) hydrazinecarbothioamide derivatives with the general formulation [ML1Cl] and [ML2Cl], where M = Mn2+, Cu2+, and Zn2+ were prepared and well discussed by using elemental analyses, magnetic moments, molar conductance, infrared and electronic spectral techniques. The assignments data of spectroscopic analysis confirm that the synthesized thiosemicarbazone Schiff bases of acts as a tridentate ligand as sulfur-oxygen-nitrogen donating atoms. The values of magnetic moments agreed with the data of electronic spectra which both suggested a four-coordination geometry of the synthesized complexes.                     KEY WORDS: Schiff base, Thiosemicarbazone, Manganese(II) complex, Copper(II) complex, Zinc(II) complex   Bull. Chem. Soc. Ethiop. 2021, 35(2), 413-424. 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

In situ acetonitrile/water mixed solvents: An ecofriendly synthesis and structure Explanations of Cu(II), Co(II), and Ni(II) complexes of thioxoimidazolidine

ABSTRACT. The bidentate oxoacetate derivative of 4-oxo-2-thiazolidine 4ligand (L1) synthesized by the reaction of 1-(1-(Pyridin-3-yl)ethylideneamino)-2-thioxoimidazolidin-4-one 3 with diethyl oxalate with both traditional and microwave irradiation methods. The metal ion complexes of mixed ligands L1 and L2 (acetonitrile) were prepared by condensation a solution mixture of Co(II) Ni(II), and Cu(ІІ) metal chloride salts with the ligands (L1 and L2) in distilled water with stirring. The complexes were characterized by the micro analysis (C, H, N), chloride content, FT-IR, UV-Vis spectra, thermal gravimetric analysis (TGA), molar conductivity as well as magnetic susceptibility measurement. According to the obtained data the suggested coordination geometries of these complexes were suggested as octahedral structure. All the synthesized complexes were found to be electrolyte due to the presence of chloride ions outside the coordination sphere. The antibacterial activity of the L1 ligand and their metal ion complexes have been studied by screening against various microorganisms, G+ bacteria (Bacillus subtillis, Streptococcus pneumonia, and Staphyloccoccus aurease), G-bacteria (E. coli, and Pesudomonas Sp.) and fungi (Aspergillus nigaer, and Penicillium Sp.). The metal ion complexes gave the formulae: [M(L1)(L2)2(H2O)2]Cl2where M = Co(II) Ni(II), and Cu(ІІ).                     KEY WORDS: Imidazolidine, Microwave irradiation, Transition metals complexes, Biological activity   Bull. Chem. Soc. Ethiop. 2021, 35(2), 351-364. DOI: https://dx.doi.org/10.4314/bcse.v35i2.1

Synthesis, characterization and microstructural evaluation of ZnO nanoparticles by William-Hall and size-strain plot methods

ABSTRACT. At various calcination temperatures 450, 550 and 650 °C, zinc oxide nanoparticles were produced. Calcinated ZnO has high surface area as the BET was 119.12 m2g–1 and the average particle radius was calculated to be 1.16 nm. The dimension of crystallites and straining in ZnO nanoparticles' diffraction peaks remained measured. The Williamson–Hall (W–H) technique besides the size–strain approach stayed used. For each of XRD reflection peaks, physical characteristics like strain and stress were computed. Towards regulate the magnitude of crystallites, the Williamson–Hall (W–H) approach besides the size–strain technique are used that is good agreement with the size that determine from SEM as it was 22.6, 26.6 and 32.6 nm for ZnO calcinated at 450, 550 and 650 oC, individually. Using the W–H plot to modify the subversion shape, assuming an unvarying distortion model (UDM), unvarying stress deformation model (USDM), unvarying deformation energy density model (UDEDM), and The size–strain plan (SSP) approach was used to determine this. The SEM and Scherrer methods match well with the crystal size of ZnO NPs determined using W–H plots and the SSP technique.     KEY WORDS: Zinc oxide nanosphere, Calcination, Physical characterization, W–H investigation, SSP technique Bull. Chem. Soc. Ethiop. 2022, 36(4), 815-829.                                                           DOI: https://dx.doi.org/10.4314/bcse.v36i4.8                                                       &nbsp

Efficient adsorption of Rhodamine B using a composite of Fe3O4@zif-8: Synthesis, characterization, modeling analysis, statistical physics and mechanism of interaction

ABSTRACT. The utilization of a metal organic framework (ZIF-8) modified by Fe3O4 nanoparticles was used to accomplish adsorption of Rhodamine B (RB) from aqueous solutions. SEM, XRD, IR, and BET analyses were all used to characterize the composite (Fe3O4@ZIF-8). The surface area of this adsorbent was 478.4 m2/g. X-Ray diffraction spectroscopy was used to detect surface modification utilizing electron microscopy (SEM) scanning with 48 nm in diameter average particle size according to a statistical physics method. Fe3O4@ZIF-8 appears to have dispersive interactions and pore characteristics, according to quantum chemistry simulations. On the adsorption of RB, the influences of contact time, adsorbent quantity, dye concentration, and temperature were studied. The Langmuir and Freundlich adsorption isotherm models were used to study the adsorption isotherms. Anticipated overall adsorption potential was 647.5 mg/g, with a zero-charge point (pHPZC) of 4.3. The adsorption isotherm was fitted using Langmuir whereas pseudo second order was used to match the kinetics. Energy of adsorption (Ea) is 28.7 kJ/mol, indicating a chemisorption phase. The adsorption process is endothermic and unpredictable, according to thermodynamic experiments. It was also looked into using ethanol as a solvent in the desorption of deposited cationic dye.   KEY WORDS: Fe3O4@ZIF-8, Rhodamine B, Adsorption models, Thermodynamics   Bull. Chem. Soc. Ethiop. 2023, 37(1), 211-229.                                                                DOI: https://dx.doi.org/10.4314/bcse.v37i1.17                                                     &nbsp

Measuring the burden of arboviral diseases: the spectrum of morbidity and mortality from four prevalent infections

<p>Abstract</p> <p>Background</p> <p>Globally, arthropod-borne virus infections are increasingly common causes of severe febrile disease that can progress to long-term physical or cognitive impairment or result in early death. Because of the large populations at risk, it has been suggested that these outcomes represent a substantial health deficit not captured by current global disease burden assessments.</p> <p>Methods</p> <p>We reviewed newly available data on disease incidence and outcomes to critically evaluate the disease burden (as measured by disability-adjusted life years, or DALYs) caused by yellow fever virus (YFV), Japanese encephalitis virus (JEV), chikungunya virus (CHIKV), and Rift Valley fever virus (RVFV). We searched available literature and official reports on these viruses combined with the terms "outbreak(s)," "complication(s)," "disability," "quality of life," "DALY," and "QALY," focusing on reports since 2000. We screened 210 published studies, with 38 selected for inclusion. Data on average incidence, duration, age at onset, mortality, and severity of acute and chronic outcomes were used to create DALY estimates for 2005, using the approach of the current Global Burden of Disease framework.</p> <p>Results</p> <p>Given the limitations of available data, nondiscounted, unweighted DALYs attributable to YFV, JEV, CHIKV, and RVFV were estimated to fall between 300,000 and 5,000,000 for 2005. YFV was the most prevalent infection of the four viruses evaluated, although a higher proportion of the world's population lives in countries at risk for CHIKV and JEV. Early mortality and long-term, related chronic conditions provided the largest DALY components for each disease. The better known, short-term viral febrile syndromes caused by these viruses contributed relatively lower proportions of the overall DALY scores.</p> <p>Conclusions</p> <p>Limitations in health systems in endemic areas undoubtedly lead to underestimation of arbovirus incidence and related complications. However, improving diagnostics and better understanding of the late secondary results of infection now give a first approximation of the current disease burden from these widespread serious infections. Arbovirus control and prevention remains a high priority, both because of the current disease burden and the significant threat of the re-emergence of these viruses among much larger groups of susceptible populations.</p

Consanguinity and reproductive health among Arabs

Consanguineous marriages have been practiced since the early existence of modern humans. Until now consanguinity is widely practiced in several global communities with variable rates depending on religion, culture, and geography. Arab populations have a long tradition of consanguinity due to socio-cultural factors. Many Arab countries display some of the highest rates of consanguineous marriages in the world, and specifically first cousin marriages which may reach 25-30% of all marriages. In some countries like Qatar, Yemen, and UAE, consanguinity rates are increasing in the current generation. Research among Arabs and worldwide has indicated that consanguinity could have an effect on some reproductive health parameters such as postnatal mortality and rates of congenital malformations. The association of consanguinity with other reproductive health parameters, such as fertility and fetal wastage, is controversial. The main impact of consanguinity, however, is an increase in the rate of homozygotes for autosomal recessive genetic disorders. Worldwide, known dominant disorders are more numerous than known recessive disorders. However, data on genetic disorders in Arab populations as extracted from the Catalogue of Transmission Genetics in Arabs (CTGA) database indicate a relative abundance of recessive disorders in the region that is clearly associated with the practice of consanguinity

Infection and Transmission of Rift Valley Fever Viruses Lacking the NSs and/or NSm Genes in Mosquitoes: Potential Role for NSm in Mosquito Infection

Rift Valley fever virus is transmitted mainly by mosquitoes and causes disease in humans and animals throughout Africa and the Arabian Peninsula. The impact of disease is large in terms of human illness and mortality, and economic impact on the livestock industry. For these reasons, and because there is a risk of this virus spreading to Europe and North America, it is important to develop a vaccine that is stable, safe and effective in preventing infection. Potential vaccine viruses have been developed through deletion of two genes (NSs and NSm) affecting virus virulence. Because this virus is normally transmitted by mosquitoes we must determine the effects of the deletions in these vaccine viruses on their ability to infect and be transmitted by mosquitoes. An optimal vaccine virus would not infect or be transmitted. The viruses were tested in two mosquito species: Aedes aegypti and Culex quinquefasciatus. Deletion of the NSm gene reduced infection of Ae. aegypti mosquitoes indicating a role for the NSm protein in mosquito infection. The virus with deletion of both NSs and NSm genes was the best vaccine candidate since it did not infect Ae. aegypti and showed reduced infection and transmission rates in Cx. quinquefasciatus

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

AMP-Activated Kinase Restricts Rift Valley Fever Virus Infection by Inhibiting Fatty Acid Synthesis

The cell intrinsic innate immune responses provide a first line of defense against viral infection, and often function by targeting cellular pathways usurped by the virus during infection. In particular, many viruses manipulate cellular lipids to form complex structures required for viral replication, many of which are dependent on de novo fatty acid synthesis. We found that the energy regulator AMPK, which potently inhibits fatty acid synthesis, restricts infection of the Bunyavirus, Rift Valley Fever Virus (RVFV), an important re-emerging arthropod-borne human pathogen for which there are no effective vaccines or therapeutics. We show restriction of RVFV both by AMPK and its upstream activator LKB1, indicating an antiviral role for this signaling pathway. Furthermore, we found that AMPK is activated during RVFV infection, leading to the phosphorylation and inhibition of acetyl-CoA carboxylase, the first rate-limiting enzyme in fatty acid synthesis. Activating AMPK pharmacologically both restricted infection and reduced lipid levels. This restriction could be bypassed by treatment with the fatty acid palmitate, demonstrating that AMPK restricts RVFV infection through its inhibition of fatty acid biosynthesis. Lastly, we found that this pathway plays a broad role in antiviral defense since additional viruses from disparate families were also restricted by AMPK and LKB1. Therefore, AMPK is an important component of the cell intrinsic immune response that restricts infection through a novel mechanism involving the inhibition of fatty acid metabolism