806 research outputs found
On the KreinâMilman Property and the Bade Property
AbstractThroughout this paper a study on the KreinâMilmam Property and the Bade Property is entailed reaching the following conclusions: If a real topological vector space satisfies the KreinâMilmam Property, then it is Hausdorff; if a real topological vector space satisfies the KreinâMilmam Property and is locally convex and metrizable, then all of its closed infinite dimensional vector subspaces have uncountable dimension; if a real pseudo-normed space has the Bade Property, then it is Hausdorff as well but could allow closed infinite dimensional vector subspaces with countable dimension. On other hand, we show the existence of infinite dimensional closed subspaces of ââ with the Bade Property that are not the space of convergence associated to any series in a real topological vector space. Finally, we characterize unconditionally convergent series in real Banach spaces by means of a new concept called uniform convergence of series
S wave velocity structure below central Mexico using high-resolution surface wave tomography
Shear wave velocity of the crust below central Mexico is estimated using surface wave dispersion measurements from regional earthquakes recorded on a dense, 500 km long linear seismic network. Vertical components of regional records from 90 well-located earthquakes were used to compute Rayleigh-wave group-velocity dispersion curves. A tomographic inversion, with high resolution in a zone close to the array, obtained for periods between 5 and 50 s reveals significant differences relative to a reference model, especially at larger periods (>30 s). A 2-D S wave velocity model is obtained from the inversion of local dispersion curves that were reconstructed from the tomographic solutions. The results show large differences, especially in the lower crust, among back-arc, volcanic arc, and fore-arc regions; they also show a well-resolved low-velocity zone just below the active part of the Trans Mexican Volcanic Belt (TMVB) suggesting the presence of a mantle wedge. Low densities in the back arc, inferred from the low shear wave velocities, can provide isostatic support for the TMVB
Effectiveness of Romanomermis culicivorax (Nematoda, Mermithidae) in Anopheles pseudopunctipennis and Culex quinquefasciatus (Diptera, Culicidae) in Mexico
Isolation of entomopathogenic nematodes and control of Phyllophaga vetula Horn in Oaxaca, Mexico
This study aimed to isolate native entomopathogenic nematodes (EPN) in the Central Valleys of Oaxaca and to determine their potential for control of white grub (Phyllophaga vetula Horn). Fifty-five (55) soil samples were collected in 13 communities in the period August to October 2008 and 29.1% of these were found positive for EPN. Five isolates were selected for their apparent pathogenicity to third instar Galleria mellonella; two of the genus Steinernema and three Heterorhabditis. After evaluating these five isolates for control of white grubs, the Heterorhabditidae EPN presented the lowest values for both lethal dosages and lethal times. Using polymerase chain reaction (PCR) procedures, the species Heterorhabditis mexicana, Steinernema carpocapsae and Steinernema feltiae were identified. We concluded that H. mexicana was the most effective isolate for control of P. vetula larvae.Key words: Entomopathogenic nematodes, Steinernema, Heterorhabditis, bioassays, lethal dosages
Weak-antilocalization signatures in the magnetotransport properties of individual electrodeposited Bi Nanowires
We study the electrical resistivity of individual Bi nanowires of diameter 100 nm fabricated by electrodeposition using a four-probe method in the temperature range 5-300 K with magnetic fields up to 90 kOe. Low-resistance Ohmic contacts to individual Bi nanowires are achieved using a focused ion beam to deposit W-based nanocontacts. Magnetoresistance measurements show evidence for weak antilocalization at temperatures below 10 K, with a phase-breaking length of 100 nm
Apoptosis of peritoneal leucocytes during early stages of Fasciola hepatica infections in sheep
Several immunomodulatory properties have been described in Fasciola hepatica infections. Apoptosis has been shown to be an effective mechanism to avoid the immune response in helminth infections. The aim of the present work was to study apoptosis in peritoneal leucocytes of sheep experimentally infected with F. hepatica during the early stages of infection. Five groups (n = 5) of sheep were used. Groups 2â5 were orally infected with 200 metacercariae (mc) and sacrificed at 1, 3, 9 and 18 days post-infection (dpi), respectively. Group 1 was used as the uninfected control (UC). Apoptosis was detected using three different methods 1) immunocytochemistry (ICC) with a polyclonal antibody anti-active caspase-3; 2) an annexin V flow cytometry assay using the Annexin V-FITC/propidium iodide (PI); and 3) transmission electron microscopy (TEM). The differential leucocyte count revealed that the majority of peritoneal granulocytes were eosinophils, which increased significantly at 9 and 18 dpi with respect to the uninfected controls. The ICC study revealed that the percentage of caspase-3+ apoptotic peritoneal leucocytes increased significantly from 3 dpi onwards with respect to the uninfected controls. The flow cytometry annexin V assay detected a very significant (P < 0.001) increase of apoptotic peritoneal macrophages, lymphocytes and granulocytes, which remained higher than in the UC until 18 dpi. Transmission electron microscopy studies also confirmed the presence of apoptosis in peritoneal eosinophils at 18 dpi. This is the first report of apoptosis induced by F. hepatica in the peritoneal leucocytes of sheep in vivo. The results of this work suggest the importance of apoptosis induction for the survival of the juvenile parasites in the peritoneal migratory stages of infection.This work was supported by EU grants (H2020-635408-PARAGONE) and the Spanish Ministry of Science grant AGL2015-67023-C2-1-R. The TEM studies were carried out by the Central Research Services (SCAI) of the University of CĂłrdobaAccepted manuscriptVeterinari
Distribution of Foxp3+ T cells in the liver and hepatic lymph nodes of goats and sheep experimentally infected with Fasciola hepatica
Foxp3 regulatory T cells (Tregs) are now considered to play a key role in modulation of immune responses during parasitic helminth infections. Immunomodulation is a key factor in Fasciola hepatica infection; however, the distribution and role of Foxp3+ Tregs cells have not been investigated in F. hepatica infected ruminants. The aim of this study was to evaluate the presence of Foxp3+ Tregs in the liver and hepatic lymph nodes from experimentally infected sheep and goats during acute and chronic stages of infection. Three groups of goats (n=6) and three groups of sheep (n=6) were used in this study. Goats in groups 1-2 and sheep in groups 4-5 were orally infected with metacercarie of ovine origin. Groups 1 and 4 were killed during the acute stage of the infection, at nine days post infection (dpi); groups 2 and 5 were killed during the chronic stage, at 15 and19 weeks post infection respectively (wpi). Groups 3 (goats) and 6 (sheep) were left as uninfected controls. Fluke burdens and liver damage were assessed and the avidin-biotin-complex method was used for the immunohistochemical study. At nine dpi in acute hepatic lesions, the number of both Foxp3+ and CD3+ T lymphocytes increased significantly in goats and sheep. In the chronic stages of infection (15-19wpi), the number of Foxp3+ and CD3+ T lymphocytes were also significantly increased with respect to control livers, particularly in portal spaces with severely enlarged bile ducts (response to adult flukes) while the increase was lower in granulomas, chronic tracts and smaller portal spaces (response to tissue damage). Foxp3+ Tregs were increased in the cortex of hepatic lymph nodes of sheep (chronic infection) and goats (acute and chronic infection). The estimated proportion of T cells which were Foxp3+ was significantly increased in the large bile ducts and hepatic lymph node cortex of chronically infected goats but not sheep. This first report of the expansion of Foxp3+ Tregs in acute and chronic hepatic lesions in ruminants suggests that these cells may be involved in both parasite survival and modulation of hepatic damage. Future studies should be focused on the investigation of parasite molecules and cytokines involved in this process.This work was supported by EU grants (H2020-635408-PARAGONE) and the Spanish Ministry of Science grant AGL2015-67023-C2-1-R. TM receives funding from the Scottish Government.Accepted manuscriptVeterinari
Comparative dynamics of peritoneal cell immunophenotypes in sheep during the early and late stages of the infection with Fasciola hepatica by flow cytometric analysis
Background: The peritoneal cell populations (PCP) are thought to play a crucial role during the early immune response
in Fasciola hepatica infection while newly excysted juveniles (NEJ) are migrating in the peritoneal cavity (PC) towards the
liver. In this study, we aimed to determine the immunophenotypes of the PCP and to analyse the dynamics of the
recruitment of the PCP during the early and late stage of the infection in sheep infected with F. hepatica.
Methods: Thirty-seven sheep were divided into three groups: Group 1 (n = 20) and 2 (n = 10) were challenged with
F. hepatica, Group 3 (n = 7) was not infected and remained as uninfected control (UC). After the slaughtering, peritoneal
lavages were carried out to isolate peritoneal cell populations at 1, 3, 9 and 18 days post-infection (dpi) for Group 1 and
at 14 weeks post-infection (wpi) for Group 2 and 3. Flow cytometry was conducted to assess the dynamics of peritoneal
cavity cell populations.
Results: TCD4 cells showed a significant decrease at 1 and 18 dpi when compared to UC; no statistical differences were
detected for TCD8 and WC1+
γΎ during the early stage of the infection with respect to the UC. CD14 cells exhibited a
decreasing trend, with a significant decrease at 9 and 18 dpi when compared to the UC. The dynamics of MHCII and
CD83 cells showed a similar increasing pattern from 3 to 18 dpi. During the chronic stage, both TCD4 and TCD8 cells
showed no significant differences when compared to the UC, although a slight but statistically significant higher level of
WC1+
γΎ cells was observed. A lower percentage of antigen-presenting cells (APCs) was detected with respect to the UC.
Conclusions: The recruitment of the lymphocytes subsets did not show a significant increase during the course of the
infection and only WC1+
γΎ cells displayed a significant increase at the chronic stage. For the CD14, a decreasing trend
was observed during the early stage, which was statistically significant at the chronic stage of the infection. Peritoneal
CD83 and MHCII cells developed an increasing trend during the early stage of infection, and showed a significant
decrease at the late stage of the infection.This study was funded by the European Union Grant H2020-635408- PARAGONE and by National Grant AGL2015-67023-C2-1-R. RPC was supported by an FPU grant of the Spanish Ministry of Education, Culture and Sport. Funding bodies were neither involved in the design of the study nor in analysis and interpretation of the dataVeterinari
Fasciola hepatica induces eosinophil apoptosis in the migratory and biliary stages of infection in sheep
The aim of the present work was to evaluate the number of apoptotic eosinophils in the livers of sheep experimentally infected with Fasciola hepatica during the migratory and biliary stages of infection. Four groups (n = 5) of sheep were used; groups 1â3 were orally infected with 200 metacercariae (mc) and sacrificed at 8 and 28 days post-infection (dpi), and 17 weeks post-infection (wpi), respectively. Group 4 was used as an uninfected control. Apoptosis was detected using immunohistochemistry with a polyclonal antibody against anti-active caspase-3, and transmission electron microscopy (TEM). Eosinophils were identified using the Hansel stain in serial sections for caspase-3, and by ultrastructural features using TEM. At 8 and 28 dpi, numerous caspase-3+ eosinophils were mainly found at the periphery of acute hepatic necrotic foci. The percentage of caspase -3+ apoptotic eosinophils in the periphery of necrotic foci was high (46.1â53.9) at 8 and 28 dpi, respectively, and decreased in granulomas found at 28 dpi (6%). Transmission electron microscopy confirmed the presence of apoptotic eosinophils in hepatic lesions at 8 and 28 dpi. At 17 wpi, apoptotic eosinophils were detected in the infiltrate surrounding some enlarged bile ducts containing adult flukes. This is the first report of apoptosis induced by F. hepatica in sheep and the first study reporting apoptosis in eosinophils in hepatic inflammatory infiltrates in vivo. The high number of apoptotic eosinophils in acute necrotic tracts during the migratory and biliary stages of infection suggests that eosinophil apoptosis may play a role in F. hepatica survival during different stages of infection.This work was supported by EU grants (FPVII-265862-PARAVAC, H2020-635408-PARAGONE) and the Spanish Ministry of Science grant AGL2009-08726. TEM studies were carried out by the Central Services for Research of the University of CĂłrdoba (SCAI)Veterinari
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