A survey on reflexivity of abelian topological groups,

a r t i c l e i n f o a b s t r a c t In this survey we deal with results on reflexivity of certain classes of groups, with special emphasis on the smaller class which better reflects the properties of LCA groups, namely that of strongly reflexive groups. A topological abelian group is said to be strongly reflexive if all its closed subgroups and its Hausdorff quotients as well as the closed subgroups and the Hausdorff quotients of its dual group are reflexive

Precompact noncompact reflexive abelian groups

We present a series of examples of precompact, noncompact, reflexive topological Abelian groups. Some of them are pseudocompact or even countably compact, but we show that there exist precompact non-pseudocompact reflexive groups as well. It is also proved that every pseudocompact Abelian group is a quotient of a reflexive pseudocompact group with respect to a closed reflexive pseudocompact subgroup

Strong Reflexivity of Abelian Groups

A reflexive topological group G is called strongly reflexive if each closed subgroup and each Hausdorff quotient of the group G and of itsdua l group isre flexive. In this paper we establish an adequate concept of strong reflexivity for convergence groups. We prove that complete metrizable nuclear groups and products of countably many locally compact topological groupsare BB-strongly reflexive

La oxidación de componentes grasos y formación de hexanal en la curación del salchichón

It has studied formation of alcanals of low weight (C3-C6) during the curing of standard Saucisson manufactured in pilot plant. Aldehydes content have been compared to others obtained in three batches of industrial process (I, II and III). Except to hexanal, present in important amounts, the rest of aldehydes appear in reduced levels even are not detected. Statistical correlation has not been obtained between hexanal content and oxidation levels of lipidic components titrated by peroxides value, T.B.A. number or total carbonyl compounds. However, certain correlation has been found between hexanal content and ratio of oleic/linoleic of each batch of saucisson. Absence of hexanal in all of saucissons of batch II is corresponded by a greater proportion of linoleic acid between their A.G.L. It is proposed determination of hexanal like an useful method to check whether oxidative mechanism of lipids during the curing has been corrected.Se ha estudiado la formación de alcanales de cadena corta (C3-C6) durante el proceso de curación de un salchichón estándar elaborado en planta piloto. Se ha comparado sus contenidos finales con los obtenidos para otros tres lotes de salchichón de fabricación industrial (I, II, III). Con excepción del hexanal, que se encuentra en cantidades importantes, los otros tres aldehídos aparecen en cantidades muy reducidas o incluso no se detectan. No se ha obtenido una correlación estadística entre el contenido en hexanal y los niveles de oxidación de los componentes grasos valorados a través del índice de peróxidos, el número T.B.A. o los compuestos carbonilos totales. Sin embargo, sí existe una cierta correlación entre el contenido en hexanal y las relaciones oleico/linoleico de cada lote de salchichón. La ausencia de hexanal en todos los salchichones del lote II viene correspondida por una mayor proporción de ácido linoleico entre sus AGL. Se propone la determinación de hexanal como un modo útil de comprobar si el mecanismo exudativo de las grasas durante el proceso de curación ha sido correcto

Reduction of motion effects in myocardial arterial spin labeling

Purpose To evaluate the accuracy and reproducibility of myocardial blood flow measurements obtained under different breathing strategies and motion correction techniques with arterial spin labeling. Methods A prospective cardiac arterial spin labeling study was performed in 12 volunteers at 3 Tesla. Perfusion images were acquired twice under breath-hold, synchronized-breathing, and free-breathing. Motion detection based on the temporal intensity variation of a myocardial voxel, as well as image registration based on pairwise and groupwise approaches, were applied and evaluated in synthetic and in vivo data. A region of interest was drawn over the mean perfusion-weighted image for quantification. Original breath-hold datasets, analyzed with individual regions of interest for each perfusion-weighted image, were considered as reference values. Results Perfusion measurements in the reference breath-hold datasets were in line with those reported in literature. In original datasets, prior to motion correction, myocardial blood flow quantification was significantly overestimated due to contamination of the myocardial perfusion with the high intensity signal of blood pool. These effects were minimized with motion detection or registration. Synthetic data showed that accuracy of the perfusion measurements was higher with the use of registration, in particular after the pairwise approach, which probed to be more robust to motion. Conclusion Satisfactory results were obtained for the free-breathing strategy after pairwise registration, with higher accuracy and robustness (in synthetic datasets) and higher intrasession reproducibility together with lower myocardial blood flow variability across subjects (in in vivo datasets). Breath-hold and synchronized-breathing after motion correction provided similar results, but these breathing strategies can be difficult to perform by patients

Lactic Acid Bacteria Isolated from Fermented Doughs in Spain Produce Dextrans and Riboflavin

Many lactic acid bacteria (LAB) produce metabolites with applications in the food industry, such as dextran-type exopolysaccharides (EPS) and riboflavin (vitamin B2). Here, 72 bacteria were isolated from sourdoughs made by Spanish bread-makers. In the presence of sucrose, colonies of 22 isolates showed a ropy phenotype, and NMR analysis of their EPS supported that 21 of them were dextran producers. These isolates were identified by their random amplified polymorphic DNA (RAPD) patterns and their rrs and pheS gene sequences as LAB belonging to four species (Weissella cibaria, Leuconostoc citreum, Leuconostoc falkenbergense and Leuconostoc mesenteroides). Six selected strains from the Leuconostoc (3) and Weissella (3) genera grew in the absence of riboflavin and synthesized vitamin B2. The EPS produced by these strains were characterized as dextrans by physicochemical analysis, and the L. citreum polymer showed an unusually high degree of branching. Quantification of the riboflavin and the EPS productions showed that the W. cibaria strains produce the highest levels (585–685 μg/and 6.5–7.4 g/L, respectively). Therefore, these new LAB strains would be good candidates for the development of fermented foods bio-fortified with both dextrans and riboflavin. Moreover, this is the first report of riboflavin and dextran production by L. falkenbergense.This research was funded by the Spanish Ministry of Science, Innovation and Universities, (grants RTI2018-097114-B-I00 and PCIN-2017-075), by the Basque Government Industry and Education Department (grant PIBA_2020_1_0032) and by the University of the Basque Country (General Grant to Research Groups (GIU 19/014))

Lactic Acid Bacteria Isolated from Fermented Doughs in Spain Produce Dextrans and Riboflavin

Many lactic acid bacteria (LAB) produce metabolites with applications in the food industry, such as dextran-type exopolysaccharides (EPS) and riboflavin (vitamin B2). Here, 72 bacteria were isolated from sourdoughs made by Spanish bread-makers. In the presence of sucrose, colonies of 22 isolates showed a ropy phenotype, and NMR analysis of their EPS supported that 21 of them were dextran producers. These isolates were identified by their random amplified polymorphic DNA (RAPD) patterns and their rrs and pheS gene sequences as LAB belonging to four species (Weissella cibaria, Leuconostoc citreum, Leuconostoc falkenbergense and Leuconostoc mesenteroides). Six selected strains from the Leuconostoc (3) and Weissella (3) genera grew in the absence of riboflavin and synthesized vitamin B2. The EPS produced by these strains were characterized as dextrans by physicochemical analysis, and the L. citreum polymer showed an unusually high degree of branching. Quantification of the riboflavin and the EPS productions showed that the W. cibaria strains produce the highest levels (585–685 μg/and 6.5–7.4 g/L, respectively). Therefore, these new LAB strains would be good candidates for the development of fermented foods bio-fortified with both dextrans and riboflavin. Moreover, this is the first report of riboflavin and dextran production by L. falkenbergense.This research was funded by the Spanish Ministry of Science, Innovation and Universities, (grants RTI2018-097114-B-I00 and PCIN-2017-075), by the Basque Government Industry and Education Department (grant PIBA_2020_1_0032) and by the University of the Basque Country (General Grant to Research Groups (GIU 19/014))