Behaviour of insulin Langmuir monolayers at the air–water interface under various conditions

Bovine insulin (INS) monolayers were spread from dilute HCl solution on aqueous subphases under various conditions of temperature (1525 °C), pH (110) and salt content (NaCl, Na3PO4, ZnCl2), and plots of surface pressure (π) against mean area per amino acid residue (A) were recorded during their compression at fast and slow barrier speeds. Although the characteristics and behaviour of the monolayers were significantly influenced by these variables, under none of the conditions studied did molecules of the film appear to migrate into the subphase. In most of conditions mentioned above, compression of these films seems likely to cause the partial submersion of the insulin molecules in the subphase, but these structural changes are relatively slow and essentially reversible. The formation of a relatively rigid, compact film structure, by molecular association, seems to be favoured by high subphase pH and by the presence of Zn2+ ions, while low pH and the presence of PO43 ions appear to favour the dissociation of oligomers, the extension of the monomers and the total submersion of their A chains in the subphase during compression. The presence of salts in the subphase also reduces the reversibility of the changes occurred under film compression.Ministerio de Ciencia y Tecnología | Ref. BQU2003-00949Xunta de Galici

A panel data toolbox for MATLAB

Panel Data Toolbox is a new package for MATLAB that includes functions to estimate the main econometric methods of balanced and unbalanced panel data analysis. The package includes code for the standard fixed, between and random effects estimation methods, as well as for the existing instrumental panels and a wide array of spatial panels. A full set of relevant tests is also included. This paper describes the methodology and implementation of the functions and illustrates their use with well-known examples. We perform numerical checks against other popular commercial and free software to show the validity of the result

A spatial autoregressive panel model to analyze road network spillovers on production

The production function approach is used to introduce the effect of public infrastructure on economic growth focusing on its spillover effects. We improve the existing literature both from a conceptual and methodological perspective. As regressors we incorporate variables related to the new concepts of internal and imported transport infrastructure capital stocks, which are actually used in commercial flows, calculated by network analysis performed in GIS. The internally used capital stock represents own infrastructure that benefits accessing markets within the region itself, while the imported capital stock captures the spillover effect associated to the use of the infrastructure situated in neighboring regions. From a methodological perspective, we introduce spatial interdependence into these models, applying the most recent spatial econometric techniques based on instrumental variables estimation in spatial autoregressive panel models in comparison with Maximum Likelihood estimation methods. We illustrate the methodology with Spanish provincial panel data for the period 1980–2007. Results support the hypothesis that the imported capital has a positive spillover effect on productio

Does Institutional Quality Matter for Trade? Institutional Conditions in a Sectoral Trade Framework

This article examines the extent to which national institutional quality affects bilateral sectoral trade flows, as well as whether the conditioning role of institutions for trade has been waxing or waning with time. Based on a new trade theory framework, we derive a sectoral gravity equation, including novel variables corresponding to the exporter's labor competitiveness levels, along with importer's price indices and sectoral incomes, and analyze industry-specific bilateral trade flows of 186 countries for the period 1996–2012. We address potential endogeneity and econometric drawbacks by means of the Poisson Pseudo-Maximum Likelihood estimation methods. The results indicate that both the institutional conditions at destination and the institutional distance between exporting and importing countries are relevant factors for bilateral trade. Moreover, the effect associated with institutional conditions at destination moderately increases over time. This is a robust outcome across economic sectors, with higher values for agriculture and raw materials than for manufacturing and service

From Cu(i) and Cu(i)–Cu(ii) mixed-valence clusters to 2D Cu(ii) and Cu(i) coordination polymers supported by a flexible bis-tetrazole organosulfur ligand

Three coordination compounds from the reaction of copper(II) bromide with the flexible bis-tetrazole organosulfur ligand, 1,2-bis(1-methyl-1H-tetrazole-5-ylthio)ethane (bmtte) have been isolated and characterised. The identification of polymeric 2Cu2Br4 (bmtte) (1), trinuclear [Cu3Br4(bmtte)2] (2) and tetra-nuclear [Cu2Br2(bmtte)]2 (3) compounds shows that the reaction conditions have a significant influence on the structure of the complexes formed. Moreover, two polymorphs of the 2D Cu(II )-coordination polymer 1 have been isolated and these crystallise in the monoclinic C2/m (1m) and the triclinic P1¯ (1t) space groups. The thermal stabilities and behaviour in aqueous media of compounds 1–3 were investigated along with the reactivity of compound 2 with CuBr2 and KI. The solid-state reaction between mixed-valence compound 2 with KI or the direct reaction of CuI and bmtte under microwave irradiation allowed the preparation of the polymeric 2 1Cu4 I4 (bmtte)2 (4). The redox behaviour of complexes 2 and 3 was analysed by cyclic voltammetry.Agencia Estatal de Investigación | Ref. PID2019-110218RB-I00Agencia Estatal de Investigación | Ref. PID2020-115004RB-I00Fundación CajaCanarias | Ref. 2021ECO11Xunta de GaliciaUniversidad de La Lagun

Synthesis and characterization of several rhenium(I) complexes of 2-acetylpyridine and ferrocenyl carbaldehyde derivatives of 2-hydroxybenzoic acid hydrazide

The rhenium(I) carbonyl halide (X = Cl and Br) complexes, [ReX(CO)3{H2(py)L2}] (1a, 1b) and [ReX(CO)3{H2(Fc)L2}] (2a, 2b), of the ligands derived from 2-acetylpyridine and ferrocenyl carbaldehyde derivatives of 2-hydroxybenzoic acid hydrazide [H2(py)L2 and H2(Fc)L2, respectively] have been prepared in good yield. The complexes have been characterized by elemental analysis, MS, IR, UV–Vis and 1H NMR spectroscopic methods and their structures have been elucidated by X-ray diffraction. The ligand forms a five-membered chelate ring but in H2(py)L2 it is Npyridine,N′-bidentate while it is O,N-bidentate in H2(Fc)L2 complexes. Reaction of complex 1a with copper(II) nitrate yields the unexpected aqua complex [Re{H(py)L2}(H2O)(CO)3] (3) where the ligand is monodeprotonated but maintains the coordination mode observed in 1a, as shown by X-ray diffraction. However, reaction of 1b with glycine yields a conformational polymorph of the original compound, 1b′. The X-ray study shows that the orientation of the O–H phenol group against the carbonyl amide group is the main differenceMinisterio de Educación y Ciencia | Ref. CTQ2006-05642/BQ

Evaluación de la calidad ambiental de ecosistemas acuáticos en el entorno del Parque Nacional de Doñana

Resumen de la comunicación presentada al XX Congreso de la Sociedad Española de Mutagénesis Ambiental – Córdoba 201

Optical and electrochemical properties of spirobifluorene iridanaphthalene complexes

Three new spirobifluorene iridaaromatic compounds bearing electron-withdrawing or electron-donor substituents or another iridanaphthalene moiety have been synthesized and structurally characterized. Thorough experimental and theoretical evaluation revealed that these novel systems present a high thermal, air and electrochemical stability as well as low optical and electronic energy gap values with a significant redshift of the absorption maximum in the UV-Vis spectra and predicted remarkably higher first hyperpolarizabilities compared to their organic counterparts. Therefore, the combination of a metallaaromatic system with a spirobifluorene moiety leads to the design and development of new spirobifluorene derivatives. These new systems have shown interesting optical and electronic properties making them of interest for future applications in optoelectronics.Xunta de Galicia | Ref. GRC2019/2

Omic approaches in environmental risk assessment

Resumen de la comunicación presentada al XX Congreso de la Sociedad Española de Mutagénesis Ambiental – Córdoba 201