319 research outputs found

    Gas geochemistry for the Los Azufres (Michoacán) geothermal reservoir, México

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    Gas data of the Los Azufres geothermal field were analyzed using a method based on equilibrium of the Fischer- Tropsch (FT) reaction: CH4 + 2H2O = 4H2 +CO2 and on the combined pyrite-hematite-magnetite (HSH2) reactions: 5/4 H2 +3/2 FeS2 +3/4 Fe2O3 + 7/4 H2O = 3 H2S +Fe3O4 in order to estimate reservoir temperature and excess steam. The solution of equilibrium equations produces a grid (FT-HSH2). This method is suitable for reservoirs with relatively high H2S but low H2 and NH3 concentrations in the fluid as is the case of the Los Azufres well discharges. Reservoir temperature and reservoir excess steam values were estimated for initial and present conditions in representative wells of the field to study the evolution of fluids, because of exploitation and waste fluids reinjection. This method was very useful in estimating reservoir temperatures in vapor wells, while in two-phase wells it was found that as the well produces a smaller fraction of water, the reservoir temperature estimation agrees qualitatively with results from cationic or silica geothermometers. For liquid-dominated wells the reservoir temperature estimations agree with temperatures obtained from the well simulator WELFLO. This indicates that FT-HSH2 results provide the temperature of the fluid entering the well where the last equilibrium occurs. Results show a decrease in reservoir temperatures in the southern zone of the field where intensive reinjection takes place. With exploitation, it was also noted that the deep liquid phase in the reservoir is changing to two-phase increasing the reservoir steam fraction and the non-condensable gases in well discharges

    MicroRNAs and drinking: association between the Pre-miR-27a rs895819 polymorphism and alcohol consumption in a Mediterranean population

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    Recently, microRNAs (miRNA) have been proposed as regulators in the different processes involved in alcohol intake, and differences have been found in the miRNA expression profile in alcoholics. However, no study has focused on analyzing polymorphisms in genes encoding miRNAs and daily alcohol consumption at the population level. Our aim was to investigate the association between a functional polymorphism in the pre-miR-27a (rs895819 A>G) gene and alcohol consumption in an elderly population. We undertook a cross-sectional study of PREvención con DIeta MEDiterránea (PREDIMED)-Valencia participants (n = 1007, including men and women aged 67 ± 7 years) and measured their alcohol consumption (total and alcoholic beverages) through a validated questionnaire. We found a strong association between the pre-miR-27a polymorphism and total alcohol intake, this being higher in GG subjects (5.2 ± 0.4 in AA, 5.9 ± 0.5 in AG and 9.1 ± 1.8 g/day in GG; padjusted = 0.019). We also found a statistically-significant association of the pre-miR-27a polymorphism with the risk of having a high alcohol intake (>2 drinks/day in men and >1 in women): 5.9% in AA versus 17.5% in GG; padjusted < 0.001. In the sensitivity analysis, this association was homogeneous for sex, obesity and Mediterranean diet adherence. In conclusion, we report for the first time a significant association between a miRNA polymorphism (rs895819) and daily alcohol consumption

    Somatostatin subtype-2 receptor-targeted metal-based anticancer complexes

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    Conjugates of a dicarba analogue of octreotide, a potent somatostatin agonist whose receptors are overexpressed on tumor cells, with [PtCl 2(dap)] (dap = 1-(carboxylic acid)-1,2-diaminoethane) (3), [(η 6-bip)Os(4-CO 2-pico)Cl] (bip = biphenyl, pico = picolinate) (4), [(η 6-p-cym)RuCl(dap)] + (p-cym = p-cymene) (5), and [(η 6-p-cym)RuCl(imidazole-CO 2H)(PPh 3)] + (6), were synthesized by using a solid-phase approach. Conjugates 3-5 readily underwent hydrolysis and DNA binding, whereas conjugate 6 was inert to ligand substitution. NMR spectroscopy and molecular dynamics calculations showed that conjugate formation does not perturb the overall peptide structure. Only 6 exhibited antiproliferative activity in human tumor cells (IC 50 = 63 ± 2 μ in MCF-7 cells and IC 50 = 26 ± 3 μ in DU-145 cells) with active participation of somatostatin receptors in cellular uptake. Similar cytotoxic activity was found in a normal cell line (IC 50 = 45 ± 2.6 μ in CHO cells), which can be attributed to a similar level of expression of somatostatin subtype-2 receptor. These studies provide new insights into the effect of receptor-binding peptide conjugation on the activity of metal-based anticancer drugs, and demonstrate the potential of such hybrid compounds to target tumor cells specifically. © 2012 American Chemical Society

    Circulating Adiponectin and Its Association with Metabolic Traits and Type 2 Diabetes: Gene-Diet Interactions Focusing on Selected Gene Variants and at the Genome-Wide Level in High-Cardiovascular Risk Mediterranean Subjects

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    Adiponectin is gaining renewed interest since, in addition to its possible protective role against insulin resistance and arteriosclerosis, recent studies suggest other additional favorable effects. However, the influence of gene-diet interactions on plasma adiponectin levels is still little understood. We analyzed the association between plasma adiponectin levels and various metabolic traits in a high-cardiovascular risk Mediterranean population, as well as the genetic effect of four candidate single-nucleotide polymorphisms (SNPs) in the adiponectin gene (ADIPOQ) and their interactions with the Mediterranean dietary pattern. Additionally, we explored, at the genome-wide level, the SNPs most associated with plasma adiponectin levels, as well as gene-diet interactions with the Mediterranean diet. In the 954 participants studied (aged 55-80 years), plasma adiponectin levels were strongly associated with plasma HDL-C concentrations (p = 6.6 × 10-36) and inversely related to triglycerides (p = 4.7 × 10-18), fasting glucose (p = 3.5 × 10-16) and type 2 diabetes (p = 1.4 × 10-7). Of the four pre-selected ADIPOQ candidate SNPs, the one most associated with plasma adiponectin was the -11391G > A (rs17300539) promoter SNP (p = 7.2 × 10-5, in the multivariable adjusted model). No significant interactions with the Mediterranean diet pattern were observed for these SNPs. Additionally, in the exploratory genome-wide association study (GWAS), we found new SNPs associated with adiponectin concentrations at the suggestive genome-wide level (p < 1 × 10-5) for the whole population, including the lead SNP rs9738548 (intergenic) and rs11647294 in the VAT1L (Vesicle Amine Transport 1 Like) gene. We also found other promising SNPs on exploring different strata such as men, women, diabetics and non-diabetics (p = 3.5 × 10-8 for rs2850066). Similarly, we explored gene-Mediterranean diet interactions at the GWAS level and identified several SNPs with gene-diet interactions at p < 1 × 10-5. A remarkable gene-diet interaction was revealed for the rs2917570 SNP in the OPCML (Opioid Binding Protein/Cell Adhesion Molecule Like) gene, previously reported to be associated with adiponectin levels in some populations. Our results suggest that, in this high-cardiovascular risk Mediterranean population, and even though adiponectin is favorably associated with metabolic traits and lower type 2 diabetes, the gene variants more associated with adiponectin may be population-specific, and some suggestive gene-Mediterranean diet interactions were detected

    Estimación de la repetibilidad y factores que afectan el peso al nacer y al destete en ganado bovino cebú brahman

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    Objective of this research was to estimate the repetibility for birth weight and weaning weight in Zebu Brahman cattle and the factors that influence these traits, 432 productive records was analyzed of the years 2001 to 2007 of the cattle company Inversions Mundo Nuevo, San Onofre's municipality (Sucre - Colombia). Was using the statistical program SAS MIXED (2001) to obtained variance components between and inside cow, with which was calculate the repetivility of the characteristics in studying. In the analysis of variance the effects season (birth or weaning), year (birth or weaning), order of calving and sex of the calf were considered. The mean for the birth weight was 35 + 3 kg with coefficient of variation of 9 %. The sources of variation considered in the model were not significant to birth weight. The average for the weaning weight was 241 + 30, with a coefficient of variation of 13 %, effect year was significant for this variable, and not significantly the effects sex, season and order of calving. The estimates of repetibility were 0.11 + 0.05 and 0.19 + 0.04 for birth weight and weaning weight, respectively.Con el objeto de obtener estimativos de repetibilidad para peso al nacer y al destete en ganado cebù Brahman y los factores que influyen sobre éstos, se analizaron 432 datos provenientes de 140 vacas registrados durante los años 2001 hasta 2007 de la empresa ganadera Inversiones Mundo Nuevo, Municipio de San Onofre (Sucre-Colombia). Usando modelos mixtos, se obtuvieron los componentes de varianza entre y dentro de vaca con los cuales se calculo la repetibilidad de las características en estudio. En el análisis de varianza se consideraron los efectos época (nacimiento o destete), año (nacimiento o destete), orden de partos y sexo del becerro. La media general para el peso al nacer fue de 35 ± 3 kg con coeficiente de variación de 9%. Las fuentes de variación consideradas en el modelo resultaron no significativas para peso al nacer. La media para el peso al destete fue 241 ± 30, con coeficiente de variación de 13 %, resultando significativo sobre esta variable el efecto de año, y no significativo los efectos de sexo, época y orden de parto. Los estimativos de repetibilidad fueron 0,11 + 0,05 y 0,19 + 0,04 para peso al nacer y al destete, respectivamente

    K2-137 b: an Earth-sized planet in a 4.3-hour orbit around an M-dwarf

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    We report the discovery from K2 of a transiting terrestrial planet in an ultra-short-period orbit around an M3-dwarf. K2-137 b completes an orbit in only 4.3 hours, the second-shortest orbital period of any known planet, just 4 minutes longer than that of KOI 1843.03, which also orbits an M-dwarf. Using a combination of archival images, AO imaging, RV measurements, and light curve modelling, we show that no plausible eclipsing binary scenario can explain the K2 light curve, and thus confirm the planetary nature of the system. The planet, whose radius we determine to be 0.89 +/- 0.09 Earth radii, and which must have a iron mass fraction greater than 0.45, orbits a star of mass 0.463 +/- 0.052 Msol and radius 0.442 +/- 0.044 Rsol.Comment: 12 pages, 9 figures, accepted for publication in MNRA

    Genome-Wide Association Study for Serum Omega-3 and Omega-6 Polyunsaturated Fatty Acids: Exploratory Analysis of the Sex-Specific Effects and Dietary Modulation in Mediterranean Subjects with Metabolic Syndrome

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    Many early studies presented beneficial effects of polyunsaturated fatty acids (PUFA) on cardiovascular risk factors and disease. However, results from recent meta-analyses indicate that this effect would be very low or nil. One of the factors that may contribute to the inconsistency of the results is that, in most studies, genetic factors have not been taken into consideration. It is known that fatty acid desaturase (FADS) gene cluster in chromosome 11 is a very important determinant of plasma PUFA, and that the prevalence of the single nucleotide polymorphisms (SNPs) varies greatly between populations and may constitute a bias in meta-analyses. Previous genome-wide association studies (GWAS) have been carried out in other populations and none of them have investigated sex and Mediterranean dietary pattern interactions at the genome-wide level. Our aims were to undertake a GWAS to discover the genes most associated with serum PUFA concentrations (omega-3, omega-6, and some fatty acids) in a scarcely studied Mediterranean population with metabolic syndrome, and to explore sex and adherence to Mediterranean diet (MedDiet) interactions at the genome-wide level. Serum PUFA were determined by NMR spectroscopy. We found strong robust associations between various SNPs in the FADS cluster and omega-3 concentrations (top-ranked in the adjusted model: FADS1-rs174547, p = 3.34 × 10-14; FADS1-rs174550, p = 5.35 × 10-14; FADS2-rs1535, p = 5.85 × 10-14; FADS1-rs174546, p = 6.72 × 10-14; FADS2-rs174546, p = 9.75 × 10-14; FADS2- rs174576, p = 1.17 × 10-13; FADS2-rs174577, p = 1.12 × 10-12, among others). We also detected a genome-wide significant association with other genes in chromosome 11: MYRF (myelin regulatory factor)-rs174535, p = 1.49 × 10-12; TMEM258 (transmembrane protein 258)-rs102275, p = 2.43 × 10-12; FEN1 (flap structure-specific endonuclease 1)-rs174538, p = 1.96 × 10-11). Similar genome-wide statistically significant results were found for docosahexaenoic fatty acid (DHA). However, no such associations were detected for omega-6 PUFAs or linoleic acid (LA). For total PUFA, we observed a consistent gene*sex interaction with the DNTTIP2 (deoxynucleotidyl transferase terminal interacting protein 2)-rs3747965 p = 1.36 × 10-8. For adherence to MedDiet, we obtained a relevant interaction with the ME1 (malic enzyme 1) gene (a gene strongly regulated by fat) in determining serum omega-3. The top-ranked SNP for this interaction was ME1-rs3798890 (p = 2.15 × 10-7). In the regional-wide association study, specifically focused on the FADS1/FASD2/FADS3 and ELOVL (fatty acid elongase) 2/ELOVL 5 regions, we detected several statistically significant associations at p < 0.05. In conclusion, our results confirm a robust role of the FADS cluster on serum PUFA in this population, but the associations vary depending on the PUFA. Moreover, the detection of some sex and diet interactions underlines the need for these associations/interactions to be studied in all specific populations so as to better understand the complex metabolism of PUFA

    Chronological Age Interacts with the Circadian Melatonin Receptor 1B Gene Variation, Determining Fasting Glucose Concentrations in Mediterranean Populations. Additional Analyses on Type-2 Diabetes Risk

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    Gene-age interactions have not been systematically investigated on metabolic phenotypes and this modulation will be key for a better understanding of the temporal regulation in nutrigenomics. Taking into account that aging is typically associated with both impairment of the circadian system and a decrease in melatonin secretion, we focused on the melatonin receptor 1B (MTNR1B)-rs10830963 C>G variant that has been associated with fasting glucose concentrations, gestational diabetes, and type-2 diabetes. Therefore, our main aim was to investigate whether the association between the MTNR1B-rs10830963 polymorphism and fasting glucose is age dependent. Our secondary aims were to analyze the polymorphism association with type-2 diabetes and explore the gene-pregnancies interactions on the later type-2 diabetes risk. Three Mediterranean cohorts (n = 2823) were analyzed. First, a cross-sectional study in the discovery cohort consisting of 1378 participants (aged 18 to 80 years; mean age 41 years) from the general population was carried out. To validate and extend the results, two replication cohorts consisting of elderly individuals were studied. In the discovery cohort, we observed a strong gene-age interaction (p = 0.001), determining fasting glucose in such a way that the increasing effect of the risk G-allele was much greater in young (p = 5.9 × 10-10) than in elderly participants (p = 0.805). Consistently, the association of the MTNR1B-rs10830963 polymorphism with fasting glucose concentrations in the two replication cohorts (mean age over 65 years) did not reach statistical significance (p > 0.05 for both). However, in the elderly cohorts, significant associations between the polymorphism and type-2 diabetes at baseline were found. Moreover, in one of the cohorts, we obtained a statistically significant interaction between the MTNR1B polymorphism and the number of pregnancies, retrospectively assessed, on the type-2 diabetes risk. In conclusion, the association of the MTNR1B-rs10830963 polymorphism with fasting glucose is age-dependent, having a greater effect in younger people. However, in elderly subjects, associations of the polymorphism with type-2 diabetes were observed and our exploratory analysis suggested a modulatory effect of the number of past pregnancies on the future type-2 diabetes genetic risk
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