Spectrometric characterization of amorphous silicon PIN detectors

During the last years, much interest has been dedicated to the use of amorphous silicon PIN diodes as particle and radiation detectors for medical applications. This work presents the spectrometric characterization of PECVD high deposition rate diodes fabricated at our laboratory, with thickness up to 17.5 μm. Results show that the studied devices detect the Am^(241) alpha particles and the medical X-rays generated by a mammograph model Senographe 700T from General Electric. Possible reasons of the observed energy losses are discussed in the lest. Using the SRIM2000 program, the transit of 5.5 MeV alpha particles through a diode was simulated, determining the optimum thickness for these particles to deposit their energy in the intrinsic layer of the diode

Tsunami generation potential of a strike slip fault tip in the westernmost Mediterranean

Tsunamis are triggered by sudden seafloor displacements, and usually originate from seismic activity at faults. Nevertheless, strike-slip faults are usually disregarded as major triggers, as they are thought to be capable of generating only moderate seafloor deformation; accordingly, the tsunamigenic potential of the vertical throw at the tips of strike-slip faults is not thought to be significant. We found the active dextral NW–SE Averroes Fault in the central Alboran Sea (westernmost Mediterranean) has a historical vertical throw of up to 5.4 m at its northwestern tip corresponding to an earthquake of Mw 7.0. We modelled the tsunamigenic potential of this seafloor deformation by Tsunami-HySEA software using the Coulomb 3.3 code. Waves propagating on two main branches reach highly populated sectors of the Iberian coast with maximum arrival heights of 6 m within 21 and 35 min, which is too quick for current early-warning systems to operate successfully. These findings suggest that the tsunamigenic potential of strike-slip faults is more important than previously thought, and should be taken into account for the re-evaluation of tsunami early-warning systems.Versión del edito

AGRONOMIC EVALUATION AND CHEMICAL COMPOSITION OF AFRICAN STAR GRASS (Cynodon plectostachyus) IN THE SOUTHERN REGION OF THE STATE OF MEXICO

African Star Grass is one of the forage resources most commonly used by farmers in regions with warm-humid climates. This study was carried out to determine the nutritional and agronomic characteristics of African Star Grass (Cynodon plectostachyus) through the following variables: crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), organic matter digestibility (OMD), net forage accumulation (NFA), stem:leaf ratio, and live:dead matter ratio in the three pastures evaluated. The work took place from April 2007 to March 2008, with evaluations carried out on a monthly basis. The data were analyzed in a randomized block design in which the blocks were the pastures, and the treatments were the months of evaluation. There were no differences between the pastures evaluated for the NDF, ADF or OMD (P>0.05). Differences were found, however, in CP, while in the monthly evaluation, differences were found between the periods evaluated (P<0.05) for these variables. Differences were also found in the agronomic evaluation of pastures (P<0.05) among height of pasture, net forage accumulation (NFA), live matter, dead matter, leaf and stem, both among pastures and in the monthly evaluations. African Star Grass can therefore be considered a good choice for milk production systems in the southern region of the state of Mexico, due to its nutritional and agronomic characteristics

Analysis of the growth of Chetumal grass established in a tropical climate

Objective: To evaluate the growth of Chetumal grass (Urochloa humidicola CIAT 679), in order to determine the optimal moment for the first harvest. Design/Methodology/Approach: A completely randomized experimental block design, with measurements repeated over time, and three repetitions was used. Morphological composition (MC), growth rate (GR), plant height (PH), intercepted radiation (IR), leaf:stem ratio (L:S), leaf:no-leaf ratio (L:NL), and aerial biomass (AB) —as well as leaf biomass (LB), stem biomass (SB), dead material (DM), net growth (NG), and total biomass (TB)— were evaluated every fifteen days, except for the two first samplings, which were carried out on a monthly basis. Data were analyzed using the GLM procedure of the SAS software and Tukey’s mean comparison test (α£0.05). Results: The morphological composition (MC) of the Chetumal grass was statistically different (p&lt;0.05), during the different growth ages. The maximum accumulation of total biomass (TB) (13,324 kg DM ha-1), leaf biomass (LB) (2,569 kg DM ha-1), and growth rate (GR) (99 kg DM ha-1 d-1) was reached at 135 DAS. On that day, the prairie reached a 68 cm plant height (PH) and 100% intercepted radiation (IR). The L:S ratio decreased from 1.62 to 0.31, while L:NL ratio changed from 1.62 to 0.22. Study Limitations/Implications: The Brachiaria humidicola cv. Chetumal grass reached its highest potential during the rainy season. Findings/Conclusions: The first cut of the Urochloa humidicola cv. Chetumal grass can be carried out at 135 DAS, when the highest accumulation of total biomass (TB), leaf biomass (LB), and growth rate (GR) is recorded

A Broad Assessment of Factors Determining Culicoides imicola Abundance: Modelling the Present and Forecasting Its Future in Climate Change Scenarios

Bluetongue (BT) is still present in Europe and the introduction of new serotypes from endemic areas in the African continent is a possible threat. Culicoides imicola remains one of the most relevant BT vectors in Spain and research on the environmental determinants driving its life cycle is key to preventing and controlling BT. Our aim was to improve our understanding of the biotic and abiotic determinants of C. imicola by modelling its present abundance, studying the spatial pattern of predicted abundance in relation to BT outbreaks, and investigating how the predicted current distribution and abundance patterns might change under future (2011–2040) scenarios of climate change according to the Intergovernmental Panel on Climate Change. C. imicola abundance data from the bluetongue national surveillance programme were modelled with spatial, topoclimatic, host and soil factors. The influence of these factors was further assessed by variation partitioning procedures. The predicted abundance of C. imicola was also projected to a future period. Variation partitioning demonstrated that the pure effect of host and topoclimate factors explained a high percentage (>80%) of the variation. The pure effect of soil followed in importance in explaining the abundance of C. imicola. A close link was confirmed between C. imicola abundance and BT outbreaks. To the best of our knowledge, this study is the first to consider wild and domestic hosts in predictive modelling for an arthropod vector. The main findings regarding the near future show that there is no evidence to suggest that there will be an important increase in the distribution range of C. imicola; this contrasts with an expected increase in abundance in the areas where it is already present in mainland Spain. What may be expected regarding the future scenario for orbiviruses in mainland Spain, is that higher predicted C. imicola abundance may significantly change the rate of transmission of orbiviruses

Differential Role of Human Choline Kinase α and β Enzymes in Lipid Metabolism: Implications in Cancer Onset and Treatment

11 pages, 6 figures, 1 table.Background The Kennedy pathway generates phosphocoline and phosphoethanolamine through its two branches. Choline Kinase (ChoK) is the first enzyme of the Kennedy branch of synthesis of 1phosphocholine, the major component of the plasma membrane. ChoK family of proteins is composed by ChoKα and ChoKβ isoforms, the first one with two different variants of splicing. Recently ChoKα has been implicated in the carcinogenic process, since it is over-expressed in a variety of human cancers. However, no evidence for a role of ChoKβ in carcinogenesis has been reported. Methodology/Principal Findings Here we compare the in vitro and in vivo properties of ChoKα1 and ChoKβ in lipid metabolism, and their potential role in carcinogenesis. Both ChoKα1 and ChoKβ showed choline and ethanolamine kinase activities when assayed in cell extracts, though with different affinity for their substrates. However, they behave differentially when overexpressed in whole cells. Whereas ChoKβ display an ethanolamine kinase role, ChoKα1 present a dual choline/ethanolamine kinase role, suggesting the involvement of each ChoK isoform in distinct biochemical pathways under in vivo conditions. In addition, while overexpression of ChoKα1 is oncogenic when overexpressed in HEK293T or MDCK cells, ChoKβ overexpression is not sufficient to induce in vitro cell transformation nor in vivo tumor growth. Furthermore, a significant upregulation of ChoKα1 mRNA levels in a panel of breast and lung cancer cell lines was found, but no changes in ChoKβ mRNA levels were observed. Finally, MN58b, a previously described potent inhibitor of ChoK with in vivo antitumoral activity, shows more than 20-fold higher efficiency towards ChoKα1 than ChoKβ. Conclusion/Significance This study represents the first evidence of the distinct metabolic role of ChoKα and ChoKβ isoforms, suggesting different physiological roles and implications in human carcinogenesis. These findings constitute a step forward in the design of an antitumoral strategy based on ChoK inhibition.This work has been supported by grants to JCL from Comunidad de Madrid (GR-SAL-0821-2004), Ministerio de Ciencia e Innovación (SAF2008-03750, RD06/0020/0016), Fundación Mutua Madrileña, and by a grant to ARM from Fundación Mutua Madrileña.Peer reviewe

Antiviral mode of action of bovine dialyzable leukocyte extract against human immunodeficiency virus type 1 infection

<p>Abstract</p> <p>Background</p> <p>Bovine dialyzable leukocyte extract (bDLE) is derived from immune leukocytes obtained from bovine spleen. DLE has demonstrated to reduce transcription of Human Immunodeficiency Virus Type 1 (HIV-1) and inactivate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway. Therefore, we decided to clarify the mode of antiviral action of bDLE on the inhibition of HIV-1 infection through a panel of antiviral assays.</p> <p>Results</p> <p>The cytotoxicity, HIV-1 inhibition activity, residual infectivity of bDLE in HIV-1, time of addition experiments, fusion inhibition of bDLE for fusogenic cells and the duration of cell protection even after the removal of bDLE were all assessed in order to discover more about the mode of the antiviral action.</p> <p>HIV-1 infectivity was inhibited by bDLE at doses that were not cytotoxic for HeLa-CD4-LTR-β-gal cells. Pretreatment of HIV-1 with bDLE did not decrease the infectivity of these viral particles. Cell-based fusion assays helped to determine if bDLE could inhibit fusion of Env cells against CD4 cells by membrane fusion and this cell-based fusion was inhibited only when CD4 cells were treated with bDLE. Infection was inhibited in 80% compared with the positive (without EDL) at all viral life cycle stages in the time of addition experiments when bDLE was added at different time points. Finally, a cell-protection assay against HIV-1 infection by bDLE was performed after treating host cells with bDLE for 30 minutes and then removing them from treatment. From 0 to 7 hours after the bDLE was completely removed from the extracellular compartment, HIV-1 was then added to the host cells. The bDLE was found to protect the cells from HIV-1 infection, an effect that was retained for several hours.</p> <p>Conclusions</p> <p>bDLE acted as an antiviral compound and prevented host cell infection by HIV-1 at all viral life cycle stages. These cell protection effects lingered for hours after the bDLE was removed. Interestingly, bDLE inhibited fusion of fusogenic cells by acting only on CD4 cells. bDLE had no virucidal effect, but could retain its antiviral effect on target cells after it was removed from the extracellular compartment, protecting the cells from infection for hours.</p> <p>bDLE, which has no reported side effects or toxicity in clinical trials, should therefore be further studied to determine its potential use as a therapeutic agent in HIV-1 infection therapy, in combination with known antiretrovirals.</p