Synthesis, structure and reactivity of Pd and Ir complexes based on new lutidine-derived NHC/phosphine mixed pincer ligands

Coordination studies of new lutidine-derived hybrid NHC/phosphine ligands (CNP) to Pd and Ir have been performed. Treatment of the square-planar [Pd(CNP)Cl](AgCl2) complex 2a with KHMDS produces the selective deprotonation at the CH2P arm of the pincer to yield the pyridine-dearomatised complex 3a. A series of cationic [Ir(CNP)(cod)]+ complexes 4 has been prepared by reaction of the imidazolium salts 1 with Ir(acac)(cod). These derivatives exhibit in the solid state, and in solution, a distorted trigonal bipyramidal structure in which the CNP ligands adopt an unusual C(axial)–N(equatorial)–P(equatorial) coordination mode. Reactions of complexes 4 with CO and H2 yield the carbonyl species 5a(Cl) and 6a(Cl), and the dihydrido derivatives 7, respectively. Furthermore, upon reaction of complex 4b(Br) with base, selective deprotonation at the methylene CH2P arms is observed. The, thus formed, deprotonated Ir complex 8b reacts with H2 in a ligand-assisted process leading to the trihydrido complex 9b, which can also be obtained by reaction of 7b(Cl) with H2 in the presence of KOtBu. Finally, the catalytic activity of Ir–CNP complexes in the hydrogenation of ketones has been briefly assessed.CTQ2013-45011-P, CTQ2016-80814-R and CTQ2014 -51912-RE

Equilibration of Concentrated Hard Sphere Fluids

We report a systematic molecular dynamics study of the isochoric equilibration of hard-sphere fluids in their metastable regime close to the glass transition. The thermalization process starts with the system prepared in a non-equilibrium state with the desired final volume fraction {\phi} but with a prescribed non-equilibrium static structure factor S_0(k; {\phi}). The evolution of the {\alpha}- relaxation time {\tau}{\alpha} (k) and long-time self-diffusion coefficient DL as a function of the evolution time tw is then monitored for an array of volume fractions. For a given waiting time the plot of {\tau}{\alpha} (k; {\phi}, tw) as a function of {\phi} exhibits two regimes corresponding to samples that have fully equilibrated within this waiting time ({\phi} \leq {\phi}(c) (tw)), and to samples for which equilibration is not yet complete ({\phi} \geq {\phi}(c) (tw)). The crossover volume fraction {\phi}(c) (tw) increases with tw but seems to saturate to a value {\phi}(a) \equiv {\phi}(c) (tw \rightarrow \infty) \approx 0.582. We also find that the waiting time t^(eq)_w({\phi}) required to equilibrate a system grows faster than the corresponding equilibrium relaxation time, t^(eq)({\phi}) \approx 0.27 \times [{\tau}{\alpha} (k; {\phi})]^1.43, and that both characteristic times increase strongly as {\phi} approaches {\phi}^(a), thus suggesting that the measurement of equilibrium properties at and above {\phi}(a) is experimentally impossible

Hydrogenation of an iridium-coordinated imidazol-2-ylidene ligand fragment

An iridium complex featuring a metalated lutidine-derived CNP ligand reacts with KOt Bu to yield a dimeric species with the two metal centers bound to the opposite ligands through the CHN arms. Furthermore, reaction with H2 in the presence of KOt Bu of the same iridium derivative results in the hydrogenation of the –CHQCH– imidazolylidene moiety of the complex. NMR spectroscopy monitoring of the latter reaction supports the initial formation of a dihydride iridium complex containing an imidazolylidene ligand fragment that is hydrogenated after prolonged reaction time.Ministerio de Economía y Competitividad de España (MINECO) y fondos FEDER de la Unión Europea-CTQ2015-69568-P, CTQ2016-80814-R y CTQ2016- 81797-RED

Lactobacillus acidophilus Contributes to a Healthy Environment for Vaginal Epithelial Cells

Lactobacillus species in the female genital tract are thought to act as a barrier to infection. Several studies have demonstrated that lactobacilli can adhere to vaginal epithelial cells. However, little is known about how the adherence of lactobacilli to vaginal epithelial cells affects the acidity, cell viability, or proliferation of the lactobacilli themselves or those of vaginal epithelial cells. Lactobacillus acidophilus was co-cultured with immortalized human vaginal epithelial cells (MS74 cell line), and the growth of L. acidophilus and the acidity of the culture medium were measured. MS74 cell density and viability were also assessed by counting cell numbers and observing the cell attachment state. L. acidophilus showed exponential growth for the first 6 hr until 9 hr, and the pH was maintained close to 4.0-5.0 at 24 hr after culture, consistent with previous studies. The growth curve of L. acidophilus or the pH values were relatively unaffected by co-culture with MS74 cells, confirming that L. acidophilus maintains a low pH in the presence of MS74 cells. This co-culture model could therefore potentially be used to mimic vaginal conditions for future in vitro studies. On the other hand, MS74 cells co-cultured with L. acidophilus more firmly attached to the culture plate, and a higher number of cells were present compared to cells cultured in the absence of L. acidophilus. These results indicate that L. acidophilus increases MS74 cell proliferation and viability, suggesting that lactobacilli may contribute to the healthy environment for vaginal epithelial cells

HR Gene Variants Identified in Mexican Patients with Alopecia Areata

Alopecia Areata (AA) is a multifactorial, dermatological disease characterized by non-scarring hair loss. Alterations in candidate genes, such as HR (Hairless), could represent a risk factor for its development. The aim of this study was to search for and analyze variants in exons 3, 15 and 17 of the HR gene in Mexican patients with AA. A total of 30 samples from both AA patients and healthy donors were analyzed in this study. Exons were amplified and sequenced using the Sanger method. Descriptive statistics and χ2 tests were used in the analysis of clinical–demographic characteristics and the comparison of allelic/genotypical frequencies between groups, respectively. The effect on protein function for the non-synonymous variants was determined with three bioinformatics servers. Three gene variants were identified in the HR gene of the evaluated patients. The benign polymorphism c.1010G \u3e A p.(Gly337Asp) (rs12675375) had been previously reported, whereas the variants c.750G \u3e A p.(Gln250Gln) and c.3215T \u3e A (Val1072AGlu) have not been described in other world populations. Both non-synonymous variants proved to be significant (p ≤ 0.05). The variant c.3215T \u3e A p.(Val1072Glu) is of particular interest due to its deleterious effect on the structure and function of the protein; therefore, it could be considered a risk factor for the development of AA

Sistema de riego inteligente utilizando electroválvulas a partir de sensores de visión

En todos los sectores en donde estén involucrados procesos para los sistemas de riego automatizados se enfrentan a un problema único, no se han mejorado para el aprovechamiento óptimo de este vital líquido, el agua, haciendo un gasto innecesario de la misma, estos sectores se dividen en sector agrícola, sector privado y sector público.Para el sector agrícola el sistema es más complejo que en los otros dos, debido a la situación actual del campo en nuestro país y por lo tanto un costo diferente.Para el sector privado el proyecto está enfocado a empresas en zonas industriales y zonas residenciales con requerimientos específicos.Para el sector público el proyecto es más global y con pocos requerimientos que los anteriores siendo de fácil acceso para costear el sistema de riego.El diseñar soluciones para el ahorro de costos y distribución del agua, basadas en nuevas formas de innovación, para dejar las formas convencionales y arcaicas que utilizan los sectores agrícola, privado y público, se busca involucrar un nuevo sector emergente en los últimos años, el de la tecnología, e incorporarlo al desarrollo sustentable en donde se ha descuidado en los últimos tiempos y cada vez se hace de más importancia. No sólo se enfoca a áreas verdes, también a jardines, campos deportivos y recreativos de carácter público y privado.En la actualidad no existe un software ni proceso parecido al sistema de riego inteligente utilizando electroválvulas a partir de sensores de visión, en comparación a productos con aspersores que dan una automatización del riego, este no lo tienen cercano a las necesidades del usuario y menos a las necesidades del gasto de agua.Palabras Claves: Electroválvulas, sensores de visión, sistema de riego inteligente

Effect of yttria addition on the microstructure and mechanical behavior of ODS ferritic alloys processed by High Energy Milling and Spark Plasma Sintering

Oxide dispersion strengthened (ODS) ferritic alloys are structural materials used in nuclear fusion reactors, which exhibit enhanced mechanical properties, as well as corrosion and irradiation resistance. In the present work, ODS ferritic alloys with composition Fe-14Cr-1.5W-0.4Ti-(0, 0.4, 0.8) Y2O3 (in wt.%) were prepared employing high energy milling (HEM) followed by Spark Plasma Sintering (SPS). The particle size distribution (PSD) of the milled powders was characterized by laser diffraction. These powders and the sintered materials produced were characterized using X-ray diffraction (XRD), and scanning electron microscopy (SEM). The sintered materials were also characterized by dilatometry, diametral compression, Vickers microhardness, and corrosion rate tests. The largest Young’s modulus, microhardness, and dimensional shrinkage/expansion were obtained for the 0.8 wt.% Y2O3 alloy. However, this alloy was the least ductile. Furthermore, the 0.8 wt.% Y2O3 alloy was the one with the least dimensional change. According to the potentiodynamic polarization studies, it was found that the protective layer of Cr2O3 formed on the surface of the three alloys studied was less effective for the yttria-free alloy, since in this case the rupture of such protective layer occurred earlier than for the case of the yttria-containing alloys. Based on these results, it is suggested that the 0.8 wt.% Y2O3 alloy having fine microstructure could constitute a potential alternative as a structural material for Gen IV-type reactors

Usos y conocimiento tradicional de las gimnospermas en el noreste de Oaxaca, México

Background and Aims: Approximately 156 gymnosperm species divided into six families occur naturally in Mexico. Oaxaca has a high richness of gymnosperms, with 45 species, and its inhabitants have an ancient knowledge about the traditional use of this group. The present study contributes to the documentation of traditional knowledge of the gymnosperms in Oaxaca, to evaluate the importance of plant families as useful resources, to understand the relationships between ethnic groups and richness of useful species, as well as to compare our records of gymnosperms with those at state and national levels.Methods: This study was carried out in 84 municipalities within three Priority Terrestrial Regions in the northeast of Oaxaca. The ethnobotanical data were collected through participant observation, ethnobotanical fieldtrips, content-free interviews of the local guides, and botanical specimens were collected. All data were analyzed qualitatively to integrate ethnofloristic and traditional knowledge, as well as ecological aspects of species studied.Key results: We recorded 30 species belonging to the families Cupressaceae, Pinaceae, Podocarpaceae and Zamiaceae. The largest number of useful species (16) registered belongs to Pinaceae. Among the Zapotecs, uses were found for 16 different species, the Mixes use ten and the Mazatec nine. All taxa registered with any use have a common name, 71% in the local language and 97% in Spanish. The most common uses were timber, construction, ornamental and fuel. The montane cloud forest is the vegetation type with the largest number of useful gymnosperms, with 15 species. Forty-five percent of the registered taxa are endemic to Mexico, six species of Pinaceae and eight of Zamiaceae are considered endemic to Oaxaca.Conclusions: This research contributes to increase records of useful gymnosperms in the state of Oaxaca. It is necessary to reconsider and understand the local value of species within the ethnic worldview in order to preserve traditional uses and promote sustainable management programs.Antecedentes y Objetivos: En México existen alrededor de 156 especies de gimnospermas nativas pertenecientes a seis familias. Para el estado de Oaxaca, se registran 45 especies de gimnospermas y sus habitantes poseen un sobresaliente conocimiento ancestral en el uso tradicional de este grupo taxonómico. El presente estudio contribuye al registro y documentación del conocimiento tradicional de las gimnospermas en Oaxaca, a evaluar la importancia de las familias botánicas como fuente de recursos, analizar las relaciones existentes entre los grupos étnicos y la riqueza de especies útiles, así como a comparar los registros obtenidos con el número de gimnospermas a nivel nacional y estatal.Métodos: El estudio se realizó en 84 municipios en tres Regiones Terrestres Prioritarias al noreste de Oaxaca. Los datos etnobotánicos fueron recopilados mediante observación participante moderada, caminatas etnobotánicas, entrevista libre a guías locales y colecta de ejemplares botánicos. Los datos se analizaron cualitativamente para integrar el conocimiento tradicional, etnoflorístico y los aspectos ecológicos de las especies.Resultados clave: Se registraron 30 especies de las familias Cupressaceae, Pinaceae, Podocarpaceae y Zamiaceae. El mayor número de especies útiles (16) registradas pertenece a Pinaceae. Entre los zapotecos se encontraron usos para 16 diferentes especies, los mixes utilizan diez y los mazatecos nueve. Todos los taxa registrados tienen nombre común, 71% en lengua local y 97% en español. Los usos más frecuentes fueron el maderable, la construcción, el ornamental y el combustible. El bosque mesófilo de montaña es el tipo de vegetación del área estudiada que contiene el mayor número de gimnospermas útiles, con 15 especies. De los taxa registrados 45% son endémicos de México, seis especies de Pinaceae y ocho de Zamiaceae se consideran endémicos de Oaxaca.Conclusiones: Este estudio incrementa los registros sobre gimnospermas útiles en el estado de Oaxaca. Se requiere reconsiderar y entender el valor local de estas especies dentro de la cosmovisión étnica, para preservar los usos tradicionales y promover programas de manejo sostenible