Modeling of homogeneous catalysis: from dft to qspr approaches

La catálisis es un campo de la ciencia que explora soluciones a los problemas ambientales como la contaminación, la eliminación de los residuos generados en el proceso de síntesis de materiales o la regeneración de los recursos naturales. En la presente Tesis, hemos reportado un estudio de cálculos DFT para la σ activación del enlace NH de amoníaco considerando las especies μ3-alquilidinos de titanio utilizando el complejo modelo [{Ti(η5-C5H5)(μ-O)}3(μ3-CH)]. Posteriormente, con el fin de analizar la hidroformilación asimétrica de estireno catalizada por complejos Rh-Binaphos, se han combinando estudios basados en la aproximación de la determinación del estado de transición y un análisis cualitativo a través de un descriptor molecular recién definido (volumen de distancia ponderada, VW). Usando nuestro conocimiento mecanicista anterior, hemos presentado un estudio QSPR para predecir la actividad y la enantioselectividad de la hidroformilación de estireno catalizada por complejos Rh-difosfinas. También, hemos desarrollado una nueva metodología 3D-QSSR para predecir la enantioselectividad basada en la cuantificación de la representación de diagramas por cuadrantes y aplicándola en el ciclopropanación asimétrica de alquenos catalizadas por complejos de cobre.Catalysis is a field of science that explores solutions to environmental problems such as pollution, elimination of waste generated in the process of materials synthesis or regeneration of natural resources. In the present Thesis, we have reported a DFT study on the N-H σ-bond activation of ammonia by the µ3-alkylidyne titanium species using the [{Ti(η5-C5H5)(µ-O)}3(µ3-CH)] model complex. Afterwards, we have combined the TS-based approach and qualitative analysis through a newly defined molecular descriptor (distance-weighted volume, VW), in order to analyze the asymmetric hydroformylation of styrene catalyzed by Rh-binaphos complexes. Using our previous mechanistic knowledge, we have presented a QSPR study to predict the activity and the enantioselectivity in the hydroformylation of styrene catalyzed by Rh-diphosphane complexes. We have also developed a new methodology to predict enantioselectivity based on the quantitative quadrant-diagram representation of the catalysts and 3D-QSSR modeling; and we have applied it in the asymmetric cyclopropanation of alkenes catalyzed by copper complexes

A Review of the Preservation of Hard and Semi-Hard Cheeses: Quality and Safety

Cheese is a dairy product with potential health benefits. Cheese consumption has increased due to the significant diversity of varieties, versatility of product presentation, and changes in consumers’ lifestyles. Spoilage of hard and semi-hard cheeses can be promoted by their maturation period and/or by their long shelf-life. Therefore, preservation studies play a fundamental role in maintaining and/or increasing their shelf-life, and are of significant importance for the dairy sector. The aim of this review is to discuss the most effective methods to ensure the safety and sensory quality of ripened cheeses. We review traditional methods, such as freezing, and modern and innovative technologies, such as high hydrostatic pressures, chemical and natural vegetable origin preservatives, vacuum and modified atmosphere packaging, edible coatings and films, and other technologies applied at the end of storage and marketing stages, including light pulses and irradiation. For each technology, the main advantages and limitations for industrial application in the dairy sector are discussed. Each type of cheese requires a specific preservation treatment and optimal application conditions to ensure cheese quality and safety during storage. The environmental impact of the preservation technologies and their contribution to the sustainability of the food chain are discussed.Financial support was provided by the Basque Government (Research Groups IT944-16). Vitoria-Gasteiz. Spain

Multifunctional albumin-stabilized gold nanoclusters for the reduction of cancer stem cells

Controlled delivery of multiple chemotherapeutics can improve the effectiveness of treatments and reduce side effects and relapses. Here in, we used albumin-stabilized gold nanoclusters modified with doxorubicin and SN38 (AuNCs-DS) as combined therapy for cancer. The chemotherapeutics are conjugated to the nanostructures using linkers that release them when exposed to different internal stimuli (Glutathione and pH). This system has shown potent antitumor activity against breast and pancreatic cancer cells. Our studies indicate that the antineoplastic activity observed may be related to the reinforced DNA damage generated by the combination of the drugs. Moreover, this system presented antineoplastic activity against mammospheres, a culturing model for cancer stem cells, leading to an efficient reduction of the number of oncospheres and their size. In summary, the nanostructures reported here are promising carriers for combination therapy against cancer and particularly to cancer stem cells.This research was funded by the Spanish Ministry of Economy and Competitiveness (CTQ2016-78454-C2-2-R, SAF2014-56763-R, and SAF2017-87305-R), Comunidad de Madrid (S2013/MIT-2850), Asociación Española Contra el Cáncer, and IMDEA Nanociencia IMDEA Nanociencia acknowledges support from the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (MINECO, Grant SEV-2016-0686

Sulfato de magnesio, ¿un nuevo aliado en el tratamiento del disconfort vesical relacionado con el catéter?

Catheter-related bladder discomfort (CRBD) is a clinical syndrome frequently observed in patients undergoing urinary catheterization. The main risk factors are male sex, catheter diameter and type of surgery. There is a wide variety of medications available for the treatment and prevention of this syndrome. The best known are antimuscarinics, which already used for the treatment of overactive bladder. These drugs have the disadvantage of producing adverse effects such as facial flushing and dry mouth. Other drugs, such as antiepileptics and analgesics, have been used for the treatment of this pathology. The last one that could be effective in the management of discomfort related to urinary catheterization is magnesium sulfate. In addition to being useful in treating various pathologies, it can be effective in reducing the incidence and severity of CRBD.El malestar vesical relacionado con el catéter es un síndrome clínico que se observa con frecuencia en pacientes sometidos a cateterismo urinario. Los principales factores de riesgo son el sexo masculino, el diámetro del catéter y el tipo de cirugía. Existe una amplia variedad de medicamentos disponibles para el control y la prevención de este síndrome. Los más conocidos son los antimuscarínicos, que ya han sido administrados para paliar los síntomas de la vejiga hiperactiva. Estos fármacos tienen la desventaja de producir efectos adversos como enrojecimiento facial y sequedad de boca. Los antiepilépticos y analgésicos, también juegan un papel importante en el tratamiento de esta patología. El último que podría ser efectivo en el manejo de las molestias relacionadas con el cateterismo urinario es el sulfato de magnesio. Además de ser útil en el tratamiento de diversas patologías, puede ser eficaz para reducir la incidencia y la gravedad de la CRBD.    

the origin of the enhanced activity of the π-acceptor phosphinine ligand

The factors governing the activity in Rh-catalyzed hydroformylation were investigated using a set of computational tools. We performed DFT calculations on the phosphinine-modified Rh catalyst [HRh(CO)3(PC5H2R3)] and compared it to the phosphane-modified HRh(CO)3(PR3) and HRh(CO)2(PR3)2 complexes. The π-acceptor phosphinine ligand coordinates preferentially at the equatorial site of the pentacoordinated Rh complex with the heterocycle perpendicular to the equatorial plane, although the ligand freely rotates around the Rh–P bond. The overall energy barrier can be divided into the following contributions: alkene complex formation, alkene rotation and alkene insertion. In the absence of steric effects (model systems), the overall barrier correlates with the computed barrier for alkene rotation. This proves that π-acceptor ligands reduce back-donation to the alkene, leading to a lower rotational barrier and, consequently, to a higher activity. The Rh–P donor–acceptor interactions were quantified using a modified version of energy decomposition analysis (EDA). In Rh–phosphinine systems, the efficient directionality of the π-back-donation, rather than the overall acceptor ability, is responsible for the high catalytic activity. Introducing steric effects increases the energy required to coordinate the alkene, increasing the overall barrier. The factors governing the activity in Rh–monophosphane catalysts seem to be related to those derived for Rh–diphosphane during the development of a QSAR model (Catal. Sci. Technol. 2012, 2, 1694). To investigate whether the findings for mono- can be extrapolated to diphosphane ligands, we re-examined our previous QSAR model using the Topological Maximum Cross Correlation (TMACC) method based on easy-to-interpret 2D-descriptors. The TMACC descriptors highlight heteroatoms close to phosphorus as activity-increasing atoms, whereas highly substituted carbon atom groups are highlighted as activity-decreasing groups

Learning of facial responses to faces associated with positive or negative emotional expressions

Subject to file availability and provided the posting includes a prominent statement of the full bibliographical details, a copyright notice in the name of the copyright holder (Cambridge University Press or the sponsoring Society, as appropriate), and a link to the online edition of the journal at Cambridge Journals Online.The possibility that facial expressions of emotion change the affective valence of faces through associative learning was explored using facial electromyography (EMG). In Experiment 1, EMG activity was registered while the participants (N = 57) viewed sequences of neutral faces (Stimulus 1 or S1) changing to either a happy or an angry expression (Stimulus 2 or S2). As a consequence of learning, participants who showed patterning of facial responses in the presence of angry and happy faces, that is, higher Corrugator Supercilii (CS) activity in the presence of angry faces and higher Zygomaticus Major (ZM) activity in the presence of happy faces, showed also a similar pattern when viewing the corresponding S1 faces. Explicit evaluations made by an independent sample of participants (Experiment 2) showed that evaluation of S1 faces was changed according to the emotional expression with which they had been associated. These results are consistent with an interpretation of rapid facial reactions to faces as affective responses that reflect the valence of the stimulus and that are sensitive to learned changes in the affective meaning of faces.This work was supported by Project SEJ2006-01576/PSIC, from the Spanish Ministerio de Ciencia y Tecnología. The participation of Francisco J. Román has been possible thanks to a FPI Grant (PSI2010- 20364) from the Spanish Ministerio de Ciencia y Tecnología

Diagnostic Biomarkers: Are We Moving from Discovery to Clinical Application?

Despite considerable research investment, moving from biomarker discovery to clinical application has presented unique challenges. We aimed to evaluate progress toward clinical application of a sample of molecular- and “omics”-based diagnostic tests over a 10-year period. METHODS We used Scopus to locate studies, published before the December 31, 2016, citing 107 original-research articles published in 2006 that assessed the diagnostic value of a molecular- or “omics”-based test. We identified diagnostic studies of the same test and disease and determined whether the article represented progress in the validation of the molecular test. We classified the types of progress: (a) clinical validation (measuring diagnostic accuracy in a series of patients similar to the population in which the test will be used in practice), (b) technical improvement, (c) extended diagnostic application (modification of the diagnostic question attended initially by the test), (d) economic evaluation, or (e) clinical use or implementation. RESULTS In the 10-year period analyzed, 4257 articles cited the 107 diagnostic studies; 118 (2.8%) were diagnostic studies of the same test, and of these papers, 25 (21.2%) did not constitute progress toward validation of the test for use in clinical practice (potential research waste). Of the 107 molecular- or “omics”-based tests described in 2006, only 28 (26.2%) appeared to have made progress toward clinical application. Only 4 (9.1%) of 44 proteomics-based tests had made progress toward clinical application. CONCLUSIONS Articles evaluating molecular- or “omics”-based diagnostic tests are numerous in biomedical journals. Few tests have made progress toward clinical application in the 10 years following their discover

Co, Zn and Ag-MOFs evaluation as biocidal materials towards photosynthetic organisms

In the present study, the biocidal activity of three different metal organic frameworks (MOFs) based on Co (Co-SIM1), Zn (Zn-SIM1) and Ag (Ag-TAZ) has been evaluated towards one green alga and two cyanobacteria. These organisms are present in fresh- and seawater and take part in the early stages of the biofouling process. The biocidal activity of these materials was evaluated by measuring chlorophyll a concentration and by inhibition zone testing. After 24 h of exposure the three different MOFs caused > 50% of chlorophyll a concentration inhibition towards both cyanobacteria, however, although the green alga presented a great sensitivity for Ag-TAZ (reaching 90% of chlorophyll a concentration inhibition), it was much more resistant to the rest of MOFs. Bioavailability of these metals was studied using ICP-MS, the chemical speciation program Visual MINTEQ, and a heavy metal bioreporter bioanalytical tool. We have elucidated that the biocidal activity presented by these MOFs was due to the dissolved metals released from them and more exactly, it depended on the bioavailability presented by these metal ions, which was closely related with the free ion concentration. This article highlights the potential use of different MOFs as biocidal material towards photosynthetic organisms and reveals important differences in the sensitivity between these organisms that should be taken into account in order to increase the biocidal spectrum of these materialsThis research was supported by the Spanish Ministry of Economy, CTM2013-45775-C2-1-R and CTM2013-45775-C2-2-

Facile synthesis of an ultramicroporous MOF tubular membrane with selectivity towards CO(2)

International audienceA substituted imidazolate-based MOF (SIM-1) membrane has been crystallized in situ on a tubular asymmetric alumina support that can be exploited for gas separation through preferential adsorption

Optimization of Modified Atmosphere Packaging for Sheep’s Milk Semi-Hard Cheese Wedges during Refrigerated Storage: Physicochemical and Sensory Properties

Modified atmosphere packaging (MAP) has become a good potential strategy to retain quality throughout the shelf life of perishable foods. The aim of this work was to evaluate different packaging atmospheres on semi-hard protected designation of origin Idiazabal cheese wedges. Six different packaging treatments (air, vacuum, and CO2/N2 gas mixtures in the ratio of 20/80, 50/50, 80/20, and 100/0% v/v, respectively) were studied. Changes in gas headspace composition, cheese gross composition, weight loss, pH, acidity, colour, and textural and sensory properties were investigated during 56 days of refrigerated storage at 5 ± 1 °C. MAP was the most effective preserving technique compared to air- and vacuum-packaging treatments. The cheese characteristics with the greatest discriminating weight in the preservation techniques were paste appearance, holes, flavour, a* (redness) and b* (yellowness) colour parameters, and slope to hardness. Air-packaged cheeses, on 35 day, presented a mouldy flavour. Vacuum packaging affected paste appearance (greasy, plastic marks, and non-homogeneous colour) and holes (occluded and unnatural appearance) starting after 14 packaging days. MAP mixtures with CO2 concentration between 50/50 and 80/20% CO2/N2 (v/v) are recommended to ensure sensory quality and stability in the distribution of these raw sheep-milk cheese wedges.The Basque Government (Consolidated Research Group IT944-16 and IT1568-22) provided financial support. Vitoria-Gasteiz, Spain