An Unsaturated Four-Coordinate Dimethyl Dimolybdenum Complex with a Molybdenum–Molybdenum Quadruple Bond

We describe the synthesis and the molecular and electronic structures of the complex [Mo2Me2{μ‐HC(NDipp)2}2] (2; Dipp=2,6‐iPr2C6H3), which contains a dimetallic core with an Mo–Mo quadruple bond and features uncommon four‐coordinate geometry and has a fourteen‐electron count for each molybdenum atom. The coordination polyhedron approaches a square pyramid, with one of the molybdenum atoms nearly co‐planar with the basal square plane, in which the trans coordination position with respect to the Mo−Me bond is vacant. The other three sites are occupied by two trans nitrogen atoms of different amidinate ligands and the methyl group. The second Mo atom occupies the apex of the pyramid and forms an Mo–Mo bond of length 2.080(1) Å, consistent with a quadruple bond. Compound 2 reacts with tetrahydrofuran (THF) and trimethylphosphine to yield the mono‐adducts [Mo2Me(μ‐Me){μ‐HC(NDipp)2}2(L)] (3⋅THF and 3⋅PMe3, respectively) with one terminal and one bridging methyl group. In contrast, 4‐dimethylaminopyridine (dmap) forms the bis‐adduct [Mo2Me2{μ‐HC(NDipp)2}2(dmap)2] (4), with terminally coordinated methyl groups. Hydrogenolysis of complex 2 leads to the bis(hydride) [Mo2H2{μ‐HC(NDipp)2}2(thf)2] (5⋅THF) with elimination of CH4. Computational, kinetic, and mechanistic studies, which included the use of D2 and of complex 2 labelled with 13C (99 %) at the Mo–CH3 sites, supported the intermediacy of a methyl‐hydride reactive species. A computational DFT analysis of the terminal and bridging coordination of the methyl groups to the Mo≣Mo core is also reported.Ministerio de Ciencia e Innovación CTQ2010-15833, CTQ2013-42501-P, CTQ2014-52769-C3-3-R, CTQ2015-64579-C3-1-P, Consolider-Ingenio 2010 CSD2007-00006Junta de Andalucía FQM-119, P09-FQM-5117Ministerio de Educación AP-4193Ministerio de Ciencia e Innovación BES-2011-04764

Effect of Yb concentration on the resistivity and lifetime of CdTe:Ge:Yb codoped crystals

The resistivity and electron lifetime of CdTe:Ge:Yb crystals are reported, demonstrating that the effect of Yb concentration is crucial for accurate electrical compensation. It is also demonstrated that the codoping of CdTe with Ge as deep donor and with Yb as rare-earth element could be a promising way to obtain semiinsulating CdTe crystals with good transport properties. High resistivity 5 10 9 cm and lifetime 9 s were obtained, thus confirming the beneficial effect of rare-earth dopingThis work has been partly supported by the projects CAM SENSORCDT S-0505/MAT/0209, CAM FOTOFLEX S-0505/ENE-123, and EU FP6 PHOLOGIC 017158. E.S. also acknowledges the Spanish MEC for the fellowship FPU 2003-1388.Peer reviewe

Psychological distress during the COVID-19 pandemic in the population of Argentina

In addition to the implications that this pandemic has had on physical health, there are other circumstances that threaten the mental health of the population, such as lockdown measures to prevent the spread of the virus, uncertainty, and the increase in infections and deaths. For this reason, this study explored indicators of psychological distress in the Argentine population, as well as its relationship with sociodemographic and health variables. Cross-sectional observational study, with data collection from May to August 2020. A total of 1112 people over the age of 18 who responded to various measurement instruments through an online questionnaire participated. A bivariate analysis and logistic regression were carried out in order to determine predictive factors of psychological distress. The data revealed that 60.9% of the sample presented psychological distress. A greater number with this condition was observed in women, apart from younger people, with a greater number of symptoms associated with the disease and with worse self-perceived health. There was no evidence of association between psychological distress and contact with people infected with coronavirus disease 2019 or with material suspicious of being infected. This research provided an overview of the mental health status of a significant population sample in Argentina, months after the onset of the coronavirus disease 2019 pandemic. These findings complement those found in other national and international studies, allowing the accumulation of evidence that states the need to demand to draw attention to the mental health of the population, especially the most vulnerable groups, on behalf of the public authoritie

Significado y concepciones de conceptos matemáticos escolares

Este estudio ejemplifica un análisis de contenido según varias componentes de significado de un concepto matemático escolar, desarrollado para tres tópicos diferentes del currículo escolar de matemáticas. El trabajo muestra diversas concepciones inferidas de las respuestas obtenidas a través de la aplicación de cuestionarios semánticos y con tres grupos diferentes de estudiantes y de futuros maestros. Tres conceptos se han elegido: la fracción, como relación parte-todo, las razones trigonométricas, así como los números positivos y negativos. En el trabajo se ejemplifica cada componente semántica diferente con solo uno de ellos. Los resultados muestran el dominio de tales nociones, sus diferentes interpretaciones, cómo han sido expresadas y los modos en que han sido usadas. Dichos resultados también muestran una variabilidad y riqueza de respuestas acerca de cada concepto, que se identifican y describen en términos de los componentes semánticos

Preparation and characterisation of calcined Mg/Al hydrotalcites impregnated with alkaline nitrate and their activities in the combustion of particulate matter

The effect of incorporating alkaline nitrates in hydrotalcites for use in the combustion of particulate matter from diesel emissions has been studied. The catalysts were characterised by X-ray diffraction (XRD), N2 adsorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), elemental analysis (EA), atomic absorption spectrophotometry (AAS) temperature programmed reduction (TPR) and Fourier transform infrared spectroscopy (FTIR). Activity measurements were carried out using a thermobalance in air and using a fixed-bed reactor with a NO/O2 flow. The observed activities decreased in the following order: HTMgAlcCs>HTMgAlcK>HTMgAlcLi>HTMgAlc.Centro de Investigación y Desarrollo en Ciencias Aplicada

Prevalence of metabolic syndrome in scholars from Bucaramanga, Colombia: a population-based study

Background: Obesity and metabolic syndrome are strongly associated with type 2 diabetes mellitus and cardiovascular diseases, thus the increasing trend in their prevalence among children and adolescents from developing countries requires a further understanding of their epidemiology and determinants. Methods and design: A cross-sectional study was designed to determine the prevalence of metabolic syndrome among 6–10 year-old children from Bucaramanga, Colombia. A two-stage random-cluster (neighborhoods, houses) sampling process was performed based on local city maps and local statistics. The study involves a domiciliary survey; including a comprehensive sociodemographic, nutritional and physical activity characterization of the children that participated in the study, followed by a complete clinical examination; including blood pressure, anthropometry, lipid profile determination, fasting glucose and insulin levels. The prevalence of metabolic syndrome will be determined using definitions and specific percentile cut-off points for this population. Finally, the association between components of metabolic syndrome and higher degrees of insulin resistance will be analyzed through a multivariable logistic regression model. This study protocol was designed in compliance with the Helsinki declaration and approved by the local ethics board. Consent was obtained from the children and their parents/guardians. Discussion: A complete description of the environmental and non-environmental factors underlying the burden of metabolic syndrome in children from a developing country like Colombia will provide policy makers, health care providers and educators from similar settings with an opportunity to guide primary and secondary preventive initiatives at both individual and community levels. Moreover, this description may give an insight into the pathophysiological mechanisms mediating the development of cardio-metabolic diseases early in life

Dietary Mg Supplementation Decreases Oxidative Stress, Inflammation, and Vascular Dysfunction in an Experimental Model of Metabolic Syndrome with Renal Failure

whether a dietary Mg supplementation might attenuate vascular dysfunction through the modulation of oxidative stress and inflammation in concurrent MetS and CKD. Methods: A rat model of MetS (Zucker strain) with CKD (5/6 nephrectomy, Nx) was used. Nephrectomized animals were fed a normal 0.1%Mg (MetS+Nx+Mg0.1%) or a supplemented 0.6%Mg (MetS+Nx+Mg0.6%) diet; Sham-operated rats with MetS receiving 0.1%Mg were used as controls. Results: As compared to controls, the MetS+Nx-Mg0.1% group showed a significant increase in oxidative stress and inflammation biomarkers (lipid peroxidation and aortic interleukin-1b and -6 expression) and Endothelin-1 levels, a decrease in nitric oxide and a worsening in uremia and MetS associated pathology as hypertension, and abnormal glucose and lipid profile. Moreover, proteomic evaluation revealed changes mainly related to lipid metabolism and CVD markers. By contrast, in the MetS+Nx+Mg0.6% group, these parameters remained largely similar to controls. Conclusion: In concurrent MetS and CKD, dietary Mg supplementation reduced inflammation and oxidative stress and improved vascular function

Epidemiologic and Clinical Impact of Acinetobacter baumannii Colonization and Infection: A Reappraisal

Acinetobacter baumannii is one of the most important antibiotic-resistant nosocomial bacteria. We investigated changes in the clinical and molecular epidemiology of A. baumannii over a 10-year period. We compared the data from 2 prospective multicenter cohort studies in Spain, one performed in 2000 (183 patients) and one in 2010 (246 patients), which included consecutive patients infected or colonized by A. baumannii. Molecular typing was performed by repetitive extragenic palindromic polymerase chain reaction (REP-PCR), pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). The incidence density of A. baumannii colonization or infection increased significantly from 0.14 in 2000 to 0.52 in 2010 in medical services (p<0.001). The number of non-nosocomial health careassociated cases increased from 1.2% to 14.2%, respectively (p<0.001). Previous exposure to carbapenems increased in 2010 (16.9% in 2000 vs 27.3% in 2010, p¼0.03). The drugs most frequently used for definitive treatment of patients with infections were carbapenems in 2000 (45%) and colistin in 2010 (50.3%). There was molecular-typing evidence of an increase in the frequency of A. baumannii acquisition in non-intensive care unit wards in 2010 (7.6% in 2000 vs 19.2% in 2010, p¼0.01). By MSLT, the ST2 clonal group predominated and increased in 2010. This epidemic clonal group was more frequently resistant to imipenem and was associated with an increased risk of sepsis, although not with severe sepsis or mortality. Some significant changes were noted in the epidemiology of A. baumannii, which is increasingly affecting patients admitted to conventional wards and is also the cause of non-nosocomial health care-associated infections. Epidemic clones seem to combine antimicrobial resistance and the ability to spread, while maintaining their clinical virulence.Ministerio de Ciencia e InnovaciónInstituto de Salud Carlos IIIEuropean Development Regional Fund “A way to achieve Europe” ERDFSpanish Network for the Research in Infectious Diseases REIPI RD06/0008FIS PI 10/00056 and PI 11/0204

Application of Pulsed Electric Fields for Obtaining Antioxidant Extracts from Fish Residues

Fish processing has serious economic and environmental costs in the food supply chain. It is necessary to find new ways to convert fish residue to added-value products, especially for main aquaculture species. In this study, a pulsed electric field (PEF) process for antioxidant extract production from three residues (gills, bones, and heads) of two commercial species (sea bream and sea bass) was tested. Three methods of extraction using two solvents (water and methanol) and a water extraction assisted by PEF were assessed. Chemical and mineral compositions, as well as amino acid profile of the by-products, were determined. In addition, four in vitro antioxidant methods, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), 2,2-azinobis-(3-ethyl-benzothiazoline-6-sulphonate radical (ABTS), ferric reducing antioxidant power assay (FRAP), and oxygen radical absorbance capacity assay (ORAC), were used to evaluate the extracts. Antioxidant activity was confirmed by DPPH and ABTS and FRAP tests, obtaining the highest values for residues from the sea bream species. ORAC values were higher in methanol than in water solvent. In general, gills were the residues with the greatest antioxidant activity for the four antioxidant assays employed. For DPPH assay, the extracts of water assisted by PEF from heads, bones, and gills yielded significant increases of 35.8%, 68.6%, and 33.8% for sea bream and 60.7%, 71.8%, and 22.1% for sea bass, respectively, with respect to water extracts. Our results suggest that PEF would be an environmentally friendly and economic choice for antioxidant-extract production from low-value by-products from fish processingHis research received external funding by the EU Commission through the BBI-JU H2020 Project AQUABIOPRO-FIT “Aquaculture and agriculture biomass side stream proteins and bioactives for feed, fitness and health promoting nutritional supplements” (Grant Agreement no. 790956). Authors would like to acknowledge to GAIN (Axencia Galega de Innovación, Xunta de Galicia, Spain) for supporting this review (grant number IN607A2019/01). Paulo E.S. Munekata acknowledges postdoctoral fellowship support from the Ministry of Economy and Competitiveness (MINECO, Spain) “Juan de la Cierva” program (FJCI-2016-29486)S