New Coordinative Compounds with 4-(4’-pyridyl)pyridinium Disubstituted Monoylides

The complexes with manganese(II), iron(II), cobalt(II), nickel(II) and copper(II) of 2-(4, 4’-bipyridin-1-ium-1-yl)-1-(4-bromophenylamino)-3-(4-methoxyphenyl)-3-oxo-1-thioxopropan-2-ide (ylide, Y) were synthesized and characterized. The obtained compounds with 1 : 2 metal/ligand ratios have been characterized by FTIR, UV Vis spectroscopy, ESI MS spectrometry, molecular conductance, magnetic measurements and thermal analysis. The ylide ligand forms chelates with metallic (II) ions through their amide nitrogen and oxygen atoms

Synthesis and Characterisation of Ag/SnO2/Clay Nanocomposites with Potential Application as Photocatalysts

This work reported a novel synthesis and characterization of Ag/SnO2/clay nanocomposites. The obtained materials were characterized using techniques such as X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy, particles size distribution, BET analyses and Scanning Electron Microscopy. The Ag/SnO2/clay nanocomposites have been used as efficient and environmentally benign photocatalysts. The protocols developed using this kind of material is advantageous in terms of simple experimentation, reusable catalyst, excellent yields of the products, short reaction time and preclusion of toxic solvents. The synthesized nanosized AgSnO2/clay nanocomposites have been used as photocatalysts for degradation and discoloration of synthetic wastewater containing Eosin Y dye, xanthene fluorescent dye, under solar radiation

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Binding of Molecular Dioxygen to the Cobalt(II) Complexes in Nonaqueous Solution

The Study discusses the possible binding of molecular oxygen to some new Co11 complexes with the Schiff base ligands of the Co(Salen) type. The investigated complexes of Co11 with the Schiff bases are: (bis(5-nitro-salicylaldehyde)ethylenediaminato)cobalt(II), Co-(NSalen); (bis(a-ethylene-salicylaldehyde)ethylenediaminato)cobalt(II), Co(EtSalen); (bis(a-ethylene-3,5-diiode-salicylaldehyde)-ethylenediaminato)cobalt(II), Co(DIEtSalen); (bis(a,5-dimethyl-3-iode-sahcylaldehyde)ethylenediaminato)cobalt(II), Co(DMISalen) and (bis(salicylaldehyde)methylene-p,p\u27-diphenylenediaminato)cobalt(II), Co(Salmbfn). The studies were based on cyclic voltammetry and UV-Vis spectrometry, in DMF solution. Electron-withdrawing substituents on the Schiff bases were found to decrease the affinity of the cobalt Schiff bases for dioxygen. Equilibrium dioxygen uptake measurements over a large range of temperatures provide the ΔH° and ΔS° values of oxygenation that fali in the range -37 to -50 kJ mol-1 for ΔH° and -117 to -157 J mol-1 K-1 for ΔS0, which is in line with the values reported for analogous dioxygen complexes described in literature

Electronic and Steric Effects in Cobalt Schiff Bases Complexes: Synthesis, Characterization and Catalytic Activity of Some Cobalt(II) Tetra-Halogens-Dimethyl Salen Complexes

International audienceThe synthesis, characterization and catalytic activity of a series of tetra-halogeno-dimethyl salen cobalt (II) complexes are reported in this paper. The investigated complexes of cobalt (II) with Schiff bases are: αα'-di-methyl Salen cobalt (II) [Co(dMeSalen)], 3,3',5,5'-tetra chloro α,α'-di-methyl Salen cobalt (II), [Co(tCldMeSalen)], 3,3'-di-bromo 5,5'-di-chloro α,α'-di-methyl Salen cobalt (II), [Co(tBrdMeSalen)], 3,3',5,5'-tetra bromo α,α'-di-methyl Salen cobalt (II), [Co(tBrdMeSalen)] and 3,3',5,5'-tetra iodo α,α'-di-methyl Salen cobalt (II), [Co(tIdMeSalen)] (where Salen is bis(salicylaldehyde)ethylenediamine). The characterization of the complexes was performed by elemental analysis, cyclic voltammetry, UV-Vis, IR and EPR spectroscopies. The study was made in DMF, and pyridine was used for coordination as axial base. The redox potential is influenced by the substituent grafted on aromatic ring and in the azomethynic position and also by the molecules coordinating in axial position (solvent, DMF, or pyridine). The catalytic oxygenation of 2,6-di-tert-butylphenol by these complexes leads to the obtention of benzoquinone and diphenoquinone products. The cobalt (II) complexes form reversible adducts with molecular oxygen

CoFe₂O₄@HaP as Magnetic Heterostructures for Sustainable Wastewater Treatment

The aim of this study was to synthesize a CoFe2O4@HaP nanocomposite (HaP-Hydroxyapatite) through the coprecipitation method in aqueous solution, with the purpose of using it in adsorption processes for the removal of Congo Red dye from aqueous solutions. Fourier Transform Infrared Spectroscopy (FT-IR) was used to characterize the synthesized material, identifying absorption bands specific to the functional groups of cobalt ferrite (Fe-O and Co-O at 603 and 472 cm−1) and hydroxyapatite PO43− at 1035, 962, 603 and 565 cm−1. Powder X-ray diffraction confirmed the cubic spinel structure of cobalt ferrite (S.G Fd-3m) and the hexagonal structure of hydroxyapatite (S.G P63/m). The nanocomposite’s crystallite size was calculated to be 57.88 nm. Nitrogen adsorption/desorption isotherms and BET specific surface area measurements were used to monitor textural parameters, revealing an increase in specific BET surface area when cobalt ferrite nanoparticles (15 m2/g) were introduced into the hydroxyapatite heterostructure (34 m2/g). Magnetic properties were investigated by interpreting hysteresis curves in the ±10 kOe range, with the nanocomposite showing a saturation magnetization of 34.83 emu/g and a coercivity value of 0.03 kOe. The adsorption capacity of the CoFe2O4@HaP nanocomposite is up to 15.25 mg/g and the pseudo-second-order kinetic model (Type 1) fits the data with a high correlation coefficient of 0.9984, indicating that the chemical adsorption determines the rate-determining step of the process. The obtained nanocomposite is confirmed by the analyses, and the absorption measurements demonstrate that it can be utilized to degrade Congo Red dye