1,012 research outputs found
Lead Exposure Is Associated with Decreased Serum Paraoxonase 1 (PON1) Activity and Genotypes
Lead exposure causes cardiac and vascular damage in experimental animals. However, there is considerable debate regarding the causal relationship between lead exposure and cardiovascular dysfunction in humans. Paraoxonase 1 (PON1), a high-density lipoprotein-associated antioxidant enzyme, is capable of hydrolyzing oxidized lipids and thus protects against atherosclerosis. Previous studies have shown that lead and several other metal ions are able to inhibit PON1 activity in vitro. To investigate whether lead exposure has influence on serum PON1 activity, we conducted a cross-sectional study of workers from a lead battery manufactory and lead recycling plant. Blood samples were analyzed for whole-blood lead levels, serum PON1 activity, and three common PON1 polymorphisms (Q192R, L55M, −108C/T). The mean blood lead level (± SD) of this cohort was 27.1 ± 15 μg/dL. Multiple linear regression analysis showed that blood lead levels were significantly associated with decreased serum PON1 activity (p < 0.001) in lead workers. This negative correlation was more evident for workers who carry the R192 allele, which has been suggested to be a risk factor for coronary heart disease. Taken together, our results suggest that the decrease in serum PON1 activity due to lead exposure may render individuals more susceptible to atherosclerosis, particularly subjects who are homozygous for the R192 allele
Galaxy formation in the Planck cosmology - III. The high-redshift universe
We present high-redshift predictions of the star formation rate distribution function (SFRDF), UV luminosity function (UVLF), galactic stellar mass function (GSMF), and specific star formation rates (sSFRs) of galaxies from the latest version of the Munich semi-analytic model L-GALAXIES. We find a good fit to both the shape and normalization of the SFRDF at z = 4–7, apart from a slight underprediction at the low-SFR end at z = 4. Likewise, we find a good fit to the faint number counts for the observed UVLF at brighter magnitudes our predictions lie below the observations, increasingly so at higher redshifts. At all redshifts and magnitudes, the raw (unattenuated) number counts for the UVLF lie above the observations. Because of the good agreement with the SFR we interpret our underprediction as an overestimate of the amount of dust in the model for the brightest galaxies, especially at high redshift. While the shape of our GSMF matches that of the observations, we lie between (conflicting) observations at z = 4–5, and underpredict at z = 6–7. The sSFRs of our model galaxies show the observed trend of increasing normalization with redshift, but do not reproduce the observed mass dependence. Overall, we conclude that the latest version of L-GALAXIES, which is tuned to match observations at z ≤ 3, does a fair job of reproducing the observed properties of galaxies at z ≥ 4. More work needs to be done on understanding observational bias at high redshift, and upon the dust model, before strong conclusions can be drawn on how to interpret remaining discrepancies between the model and observations
Galaxy formation in the Planck cosmology - I. Matching the observed evolution of star formation rates, colours and stellar masses
We have updated the Munich galaxy formation model to the Planck first-year cosmology, while modifying the treatment of baryonic processes to reproduce recent data on the abundance and passive fractions of galaxies from z = 3 down to z = 0. Matching these more extensive and more precise observational results requires us to delay the reincorporation of wind ejecta, to lower the surface density threshold for turning cold gas into stars, to eliminate ram-pressure stripping in haloes less massive than ∼1014 M⊙, and to modify our model for radio mode feedback. These changes cure the most obvious failings of our previous models, namely the overly early formation of low-mass galaxies and the overly large fraction of them that are passive at late times. The new model is calibrated to reproduce the observed evolution both of the stellar mass function and of the distribution of star formation rate at each stellar mass. Massive galaxies (log M⋆/M⊙ ≥ 11.0) assemble most of their mass before z = 1 and are predominantly old and passive at z = 0, while lower mass galaxies assemble later and, for log M⋆/M⊙ ≤ 9.5, are still predominantly blue and star forming at z = 0. This phenomenological but physically based model allows the observations to be interpreted in terms of the efficiency of the various processes that control the formation and evolution of galaxies as a function of their stellar mass, gas content, environment and time
Imperfection works: Survival, transmission and persistence in the system of Heliothis virescens ascovirus 3h (HvAV-3h), Microplitis similis and Spodoptera exigua
Ascoviruses are insect-specific large DNA viruses that mainly infect noctuid larvae, and are transmitted by parasitoids in the fields. Heliothis virescens ascovirus 3h (HvAV-3h) has been recently isolated from Spodoptera exigua, without parasitoid vector identified previously. Here we report that Microplitis similis, a solitary endoparasitoid wasp, could transmit HvAV-3h between S. exigua larvae in the laboratory. When the female parasitoid wasp acquired the virus and served as a vector, the period of virion viability on the ovipositor was 4.1 ± 1.4 days. Infected host larvae were still acceptable for egg laying by parasitoids, and the parasitoids thereafter transmitted virus to healthy hosts. Virus acquisition occurred only from donor hosts between 3 and 9 days post infection. The peak of virus acquisition (80.9 ± 6.3%) was found when M. similis wasps oviposited in larvae that had been inoculated with the virus 7 days previously. When virus infection of the host took place during the life cycle of the parasitoid wasp, it caused 1- to 4-day-old immature parasitoids death in the host, whilst a small proportion of 5- to 6-day-old and the majority of 7-day-old parasitoids larvae survived from the virus-infected hosts. Viral contamination did not reduce the life span or fecundity of female M. similis
Neutron reflection study of the adsorption of the phosphate surfactant NaDEHP onto alumina from water.
The adsorption of a phosphorus analogue of the surfactant AOT, sodium bis(2-ethylhexyl) phosphate (NaDEHP), at the water/alumina interface is described. The material is found to adsorb as an essentially water-free bilayer from neutron reflection measurements. This is similar to the behavior of AOT under comparable conditions, although AOT forms a thicker, more hydrated layer. The NaDEHP shows rather little variation with added salt, but a small thickening of the layer on increasing the pH, in contrast to the behavior of AOT.We thank BP plc and EPSRC for financial support for this work as well as the ISIS and ILL staff and scientists for the allocation of beam time and technical assistance with NR measurements. We also appreciate Chris Sporikou at Department of Chemistry, University of Cambridge, for help with the surfactant synthesis.This is the final version of the article. It first appeared at http://dx.doi.org/10.1021/la504837
Potential-pH Diagrams of Iron in Concentrated Aqueous LiBr Solutions at 25°C
[EN] Potential-pH diagrams of iron are developed in aqueous LiBr solutions with concentrations of 400 g/L, 700 g/L, 850 g/L, and 992 g/L LiBr at 25 degrees C, which are common concentrations in different parts of absorption machines. Comparison of the potential-pH diagrams of iron in the absence and the presence of concentrated aqueous LiBr solutions shows that the corrosion area at acid, neutral, and weak alkaline pH extends to lower potentials and higher pH values with the increase of LiBr concentration, as a result of formation of the aqueous species FeBr2(aq) and FeBr3(aq) and destabilization of the solid species Fe, Fe(OH)(2)(s), Fe3O4, and Fe2O3.The authors acknowledge the "Programa de Apoyo a la Investigacion y Desarrollo (PAID-06-10) de la UPV" for the support of this work, Antonio Juncos for his assistance in plotting the diagrams, and Dr. M. Asuncion Jaime for her translation assistance.Muñoz-Portero, M.; Nachiondo Farinós, TDM.; Blasco-Tamarit, E.; Vicent-Blesa, A.; Garcia-Anton, J. (2018). Potential-pH Diagrams of Iron in Concentrated Aqueous LiBr Solutions at 25°C. Corrosion. 74(10):1102-1116. https://doi.org/10.5006/2865S11021116741
Trans-natural antisense transcripts including noncoding RNAs in 10 species: implications for expression regulation
Natural antisense transcripts are at least partially complementary to their sense transcripts. Cis-Sense/Antisense pairs (cis-SAs) have been extensively characterized and known to play diverse regulatory roles, whereas trans-Sense/Antisense pairs (trans-SAs) in animals are poorly studied. We identified long trans-SAs in human and nine other animals, using ESTs to increase coverage significantly over previous studies. The percentage of transcriptional units (TUs) involved in trans-SAs among all TUs was as high as 4.13%. Particularly 2896 human TUs (or 2.89% of all human TUs) were involved in 3327 trans-SAs. Sequence complementarities over multiple segments with predicted RNA hybridization indicated that some trans-SAs might have sophisticated RNA–RNA pairing patterns. One-fourth of human trans-SAs involved noncoding TUs, suggesting that many noncoding RNAs may function by a trans-acting antisense mechanism. TUs in trans-SAs were statistically significantly enriched in nucleic acid binding, ion/protein binding and transport and signal transduction functions and pathways; a significant number of human trans-SAs showed concordant or reciprocal expression pattern; a significant number of human trans-SAs were conserved in mouse. This evidence suggests important regulatory functions of trans-SAs. In 30 cases, trans-SAs were related to cis-SAs through paralogues, suggesting a possible mechanism for the origin of trans-SAs. All trans-SAs are available at http://trans.cbi.pku.edu.cn/
Protective efficacy of catalytic bioscavenger, paraoxonase 1 against sarin and soman exposure in guinea pigs
Assessment of NER solutions against the first and second CALBC Silver Standard Corpus
Background Competitions in text mining have been used to measure the performance of automatic text processing solutions against a manually annotated gold standard corpus (GSC). The preparation of the GSC is time-consuming and costly and the final corpus consists at the most of a few thousand documents annotated with a limited set of semantic groups. To overcome these shortcomings, the CALBC project partners (PPs) have produced a large-scale annotated biomedical corpus with four different semantic groups through the harmonisation of annotations from automatic text mining solutions, the first version of the Silver Standard Corpus (SSC-I). The four semantic groups are chemical entities and drugs (CHED), genes and proteins (PRGE), diseases and disorders (DISO) and species (SPE). This corpus has been used for the First CALBC Challenge asking the participants to annotate the corpus with their text processing solutions. Results All four PPs from the CALBC project and in addition, 12 challenge participants (CPs) contributed annotated data sets for an evaluation against the SSC-I. CPs could ignore the training data and deliver the annotations from their genuine annotation system, or could train a machine-learning approach on the provided pre-annotated data. In general, the performances of the annotation solutions were lower for entities from the categories CHED and PRGE in comparison to the identification of entities categorized as DISO and SPE. The best performance over all semantic groups were achieved from two annotation solutions that have been trained on the SSC-I. The data sets from participants were used to generate the harmonised Silver Standard Corpus II (SSC-II), if the participant did not make use of the annotated data set from the SSC-I for training purposes. The performances of the participants’ solutions were again measured against the SSC-II. The performances of the annotation solutions showed again better results for DISO and SPE in comparison to CHED and PRGE. Conclusions The SSC-I delivers a large set of annotations (1,121,705) for a large number of documents (100,000 Medline abstracts). The annotations cover four different semantic groups and are sufficiently homogeneous to be reproduced with a trained classifier leading to an average F-measure of 85%. Benchmarking the annotation solutions against the SSC-II leads to better performance for the CPs’ annotation solutions in comparison to the SSC-I
- …