Boundedness of some convolution-type operators on metric measure spaces

We explore boundedness properties of some natural operators of convolution type in the context of metric measure spaces. Their study is suggested by certain transformations used in computer visionPID2019-106870GB-I0

A Fischer type decomposition theorem from the apolar inner product

We continue the study initiated by H. S. Shapiro on Fischer decompositions of entire functions, showing that such decomposition exist in a weak sense (we do not prove uniqueness) under hypotheses regarding the order of the entire function f to be expressed as f= P· q+ r , the polynomial P, and bounds on the apolar norm of homogeneous polynomials of degree m. These bounds, previously used by Khavinson and Shapiro, and by Ebenfelt and Shapiro, can be interpreted as a quantitative, asymptotic strengthening of Bombieri’s inequality. In the special case where both the dimension of the space and the degree of P are two, we characterize for which polynomials P such bounds hol

Isolation as a strategy for controlling the transmission of hepatitis C virus (HCV) infection in haemodialysis units.

BACKGROUND: The hepatitis C virus (HCV) infection affects about 2% of the world's population and can cause chronic liver infection and persistent long-term sequelae such as cirrhosis and liver cancer.The prevalence of HCV infection among people on haemodialysis is often higher than the general population. The virus is easily transmitted parenterally, and blood transfusions have previously played a significant role in transmission; however, erythropoietin therapy has reduced the need for transfusions, and coupled with improved screening of donated blood, has significantly decreased transmission by transfusion. Although control of hospital-acquired infection has improved with the advent of biosafety measures, stopping HCV transmission in haemodialysis units remains challenging.Isolating people infected with HCV involves physical separation from others to limit direct or indirect transmission and includes a number of strategies during dialysis. The evidence for isolating people infected with HCV during haemodialysis is sparse with some inconsistencies. OBJECTIVES: To evaluate the benefits and harms of isolation of HCV-infected patients during haemodialysis on the transmission of HCV to other patients. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Specialised Register to 26 November 2015 through contact with the Information Specialist using search terms relevant to this review. We also searched the Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to 2015), Web of Science Conference Proceedings Citation Index-Science (CPCI-S, 1990 to 2015), ProQuest Dissertations & Theses Database (1990 to 2015), and Open Grey (1990 to 2015). SELECTION CRITERIA: We included randomised controlled trials (RCTs), quasi-RCTs and cluster RCTs evaluating the clinical benefits and harms of isolating HCV-infected patients during haemodialysis on the transmission of HCV to other patients. We considered incidence of dialysis-acquired HCV infection, all-cause mortality, and adverse effects associated with isolation as the primary outcomes. DATA COLLECTION AND ANALYSIS: Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. MAIN RESULTS: Only one study, which included 12 centres was identified: four centres used dedicated haemodialysis machines for HCV-infected patients and eight centres used non-dedicated machines. The total number of patients enrolled was 593. One centre was excluded after randomisation. Random sequence generation was not described and allocation concealment was not performed. Participants and personnel were not blinded and blinding of outcome assessors was not reported. Only 74.5% of the patients were followed for 9 months; and 47.3% were followed for an additional 9 months. The authors only reported one outcome, measuring the difference in the incidence of HCV in both groups. The authors did not consider the exposure time, to determine the adjusted rate of seroconversion risk/patient-year. The study reported that the incidence of HCV infection during the first follow-up period (9 months) was 1.6% in the dedicated group, and 4.7% in the non-dedicated one (446 patients analysed out of 593 randomised; RR 0.34, 95% CI 0.11 to 1.07). During the second follow-up period (18 months) the incidence was 1.3% in the dedicated group and 5.8% in the control (281 patients analysed out of 593 randomised; RR 0.22, 95% CI 0.05 to 1.02). Therefore, we found no differences in terms of the number of participants developing HCV infection when comparing the dedicated group with the usual care. Moreover, the evidence was of very low quality, which means that we have very little confidence in the effect estimate. AUTHORS' CONCLUSIONS: The benefits and harms of isolation of HCV-infected patients during haemodialysis on the transmission of HCV to other patients are uncertain. Evidence from one short-duration cluster-randomised study with a high risk of bias did not find differences in terms of the number of participants developing HCV infection when comparing the use of dedicated haemodialysis machines for HCV infected patients with the use of non-dedicated machines.post-print398 K

Estudio del aprovechamiento termoquímico de residuos textiles.

La industria textil es uno de los sectores industriales más extensos e importantes del mundo. La moda rápida y el incremento de consumo de la sociedad ha supuesto un desarrollo más rápido de esta industria, lo que ha llevado a una producción masiva de textiles. Esto implica un gran problema, no solo por su producción, que muchas veces es poco sostenible sino también por los residuos que se generan. La solución más acertada ante este gran problema se basa en la economía circular: reducir, reutilizar y reciclar. Actualmente, podemos encontrar diferentes métodos de reciclaje de residuos textiles, pero no todos son útiles cuando estos residuos corresponden a diferentes mezclas de materiales. Este Trabajo de Fin de Grado se ha enfocado en el estudio de la posible aplicación de los procesos termoquímicos como solución a mezclas complejas de residuos textiles. De esta forma, se convierten estos residuos en un producto de valor añadido o combustibles. Los procesos termoquímicos que se han analizado son: la pirólisis, la torrefacción, la gasificación y la carbonización. Además, no solo se ha centrado en mezcla de textiles, sino que también se ha estudiado en fibras específicas: algodón, poliéster, viscosa y lana, ya que la mayor parte de las mezclas residuales están compuestas por diferentes porcentajes de estos materiales. Inicialmente, se ha realizado un estudio bibliográfico para conocer con detalle el estado del arte en el aprovechamiento termoquímico de estos residuos, presentándose unas tablas a modo de resumen con la información más destacada encontrada, y posteriormente se han analizado sus desarrollos, sus características y los productos generados. Finalmente, se ha centrado el trabajo en la gasificación de estos materiales, elaborándose una aplicación en EES que incorpora un modelo de gasificación, realizándose la simulación del procesado de diferentes fibras textiles y mezclas, y analizándose los resultados, y productos generados.<br /

Efficient Rhodium-catalyzed multicomponent reaction for the synthesis of novel propargylamines

[{Rh(μ-Cl)(H)2(IPr)}2] (IPr = 1,3-bis-(2,6-diisopropylphenyl)imidazole-2-ylidene) was found to be an efficient catalyst for the synthesis of novel propargylamines by a one-pot three-component reaction between primary arylamines, aliphatic aldehydes, and triisopropylsilylacetylene. This methodology offers an efficient synthetic pathway for the preparation of secondary propargylamines derived from aliphatic aldehydes. The reactivity of [{Rh(μ-Cl)(H)2(IPr)}2] with amines and aldehydes was studied, leading to the identification of complexes [RhCl(CO)IPr(MesNH2)] (MesNH2 = 2,4,6-trimethylaniline) and [RhCl(CO)2IPr]. The latter shows a very low catalytic activity while the former brought about reaction rates similar to those obtained with [{Rh(μ-Cl)(H)2(IPr)}2]. Besides, complex [RhCl(CO)IPr(MesNH2)] reacts with an excess of amine and aldehyde to give [RhCl(CO)IPr{MesN[DOUBLE BOND]CHCH2CH(CH3)2}], which was postulated as the active species. A mechanism that clarifies the scarcely studied catalytic cycle of A3-coupling reactions is proposed based on reactivity studies and DFT calculations.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO/FEDER) (CONSOLIDER INGENIO CSD2009-0050, CTQ2011-27593, CTQ2012-35665 and CTQ2013-42532-P projects) and the DGA/FSE-E07. The support from KFUPM-University of Zaragoza research agreement and the Centre of Research Excellence in Petroleum Refining & KFUPM is gratefully acknowledged. V. P. thankfully acknowledges the resources from the supercomputer >Memento>, technical expertise and assistance provided by BIFI-ZCAM (Universidad de Zaragoza). L.R.-P thanks to CONACyT for a postdoctoral fellowship (204033).Peer Reviewe

Novel homogeneous Ir-catalysts: Ligand design, applications and mechanisms

Resumen del trabajo presentado a la 2nd World Chemistry Conference and Exhibition (WCCE), celebrada en Valencia (España) del 9 al 11 de julio de 2018.This presentation will deal with two main subjects: (i) the preparation ofthe frrst PCP-type ligand based on an N-heterocyclic olefm (NHO) scaffold, accompanied by an evaluation of the impact of this type of ligand in the activity of iridium complexes in several relevant catalytic processes; and (ii) the development of well- defined Ir-NHC complexes as catalysts for the dehydrogenative silylation of aromatic C-H bonds. (i) A great variety of pincer complexes has been reported in the literature. In particular, transition metal complexes containing PCP pincer ligands have shown remarkable activities in relevant catalytic processes. Recent work by us on this subject has resulted in the preparation of an ewPCP-type ligand based on an N- heterocyclic olefin (NHO) scaffold. The flexibille coordination of this NHO-based PCP-ligand can be attributed to the dual nature (ylide-olefm) oftbe NHO. Iridium(I) complexes featuring this ligand show excellent activities in transfer hydrogenation reactions. The active species ([Ir(KP,C,P'-NHO-PPh2)(iPrO)]), formed via COD dissociation and subsequent isopropoxide coordination, features an NHO moiety that behaves as a hemilabile ligand, which allows the catalyst to adopt stabJe square planar geometries in the transition states, thus reducing the energetic barrier of the process. More recently, we have tested the activity ofthese complexes in the dehydrogenation of formic acid, showing outstanding activities in water and in neat formicacid. (ii) The preparation of fine chernicals by the catalytic functionalization of C-H bonds has seen an outstanding development in recent years, with borylation and silylation reactions being prominent examples of this chemistry. In this regard, the versatility of oganosilicon compounds can be attributed to the low cost and non-toxic nature of silicon reagents, together with their straight forward functionalization by various reactions. Moreover, conjugated organosilicon materials are attractive targets per se owing to their unique properties, which permit a widespread applicability in the field of organic electronics and photonics. Most of the catalysts employed so far for this reaction are generated >in situ> from commercial metal precursors and ligands. Hence, we have focused on the development of well-defined organometallic catalysts bearing appropriate ligands in order to improve the efficiency of current silylation catalysts. In particular, the use of NHC-Ir (III) complex [Ir(H)2(IPr)(py)3][BF4] (IPr = 1 ,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene) as a catalyst has allowed for the preparation of a wide range of aryl- and heteroarylsilanes. The directed and non-directed functionalization of C-H bonds has been accomplisbed successfully using the areneas tbe limiting reagent and a variety of hydrosilanes, including Et3SiH, Ph2MeSiH, PhMe2SiH, Ph3SiH and(Et0)3SiH.Peer Reviewe

Poesía

Contiene: Amparo Amorós "El Descendimiento". Jesús Munárriz "Monólogo del renegado". Jaime Siles "Himno a Venus". Kasterns Mikoll "Uni-Versos", "Metáforas volátiles". Felipe R. Altuzarra "Los paces... y... las penes", "(Ir)radiaciones". Luis Martínez de Mingo "Passing-Shock". Antonio Crespo Massieu "Despedida", "Otoño", "Perfil del tiempo"