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Search Results: 1 - 10 of 554058 matches for " Teresa; Méndez-Gómez Humaran "
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Prevalence of folate and vitamin B12 deficiency in Mexican children aged 1 to 6 years in a population-based survey
Cuevas-Nasu,Lucía; Mundo-Rosas,Verónica; Shamah-Levy,Teresa; Méndez-Gómez Humaran,Ignacio; ávila-Arcos,Marco Antonio; Rebollar-Campos,Ma. del Rosario; Villalpando,Salvador;
Salud Pública de México , 2012, DOI: 10.1590/S0036-36342012000200007
Abstract: objective: to describe the magnitude and distribution of folate and vitamin b12 deficiency in mexican children. materials and methods: folate and vitamin b12 serum concentrations were measured in a probabilistic sample of 2 099 children. adjusted prevalence, mean concentrations and relevant associations were calculated based on series of logistic and linear regression models. results: the overall prevalence of folate and vitamin b12 deficiency were 3.2% and 7.7%, respectively. the highest prevalence of folate was found in the 2-year-old (7.9%), and of vitamin b12 in the 1 year-old (9.1%) groups. being a beneficiary of the fortified milk program liconsa was protectively associated with serum folate (p=0.001) and daily intake of milk with vitamin b12 (p=0.002) concentrations. conclusions: we describe the magnitude of folate and vitamin b12 deficiencies in mexican children. the deficiency of both vitamins in children under 2 years old is a moderate public health problem in mexico.
Nutritional causes of anemia in Mexican children under 5 years: results from the 2006 National Health and Nutrition Survey
De la Cruz-Góngora,Vanessa; Villalpando,Salvador; Rebollar,Rosario; Shamah-Levy,Teresa; Méndez-Gómez Humarán,Ignacio;
Salud Pública de México , 2012, DOI: 10.1590/S0036-36342012000200006
Abstract: objective: to describe the frequency and severity of anemia and the nutritional variables associated to hemoglobin levels (hb) in children <5 years of age. materials and methods: we studied 981 children measuring hemoglobin and serum concentrations of ferritin, soluble transferrin receptors (stfr), c-reactive protein (crp), zinc, iron, copper, magnesium, folate and vitamin b12. ordinal logit or multiple regression models were constructed to assess the risk for anemia and the associations among nutritional variables. results: the overall prevalence of anemia was 20.6%, of which 14% were mild cases and 6.38% moderate. anemia was associated with iron deficiency (id) in 42.17% of the cases, whereas id coexisted with either folate or vitamin b12 deficiency in 9%. only 2% of cases of anemia were associated with either folate or vitamin b12 deficiencies. crp (coef: 0.17 g/dl) and third tertile of s-copper (coef: -0.85 g/dl) were associated to unexplained anemia (p<0.05). conclusions: id is the main cause of anemia in children <5 y. folate and vitamin b12 concentrations were associated with anemia. crp was associated to unexplained anemia. however, vitamin a deficiency, which is associated with anemia, was not studied.
Magnetoabsorption and magnetic hysteresis in Ni ferrite nanoparticles
Hernández-Gómez P.,Mu?oz J. M.,Valente M. A.,Torres C.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134017003
Abstract: Nickel ferrite nanoparticles were prepared by a modified sol-gel technique employing coconut oil, and then annealed at different temperatures in 400-1200 °C range. This route of preparation has revealed to be one efficient and cheap technique to obtain high quality nickel ferrite nanosized powder. Sample particles sizes obtained with XRD data and Scherrer’s formula lie in 13 nm to 138 nm, with increased size with annealing temperature. Hysteresis loops have been obtained at room temperature with an inductive method. Magnetic field induced microwave absorption in nanoscale ferrites is a recent an active area of research, in order to characterize and explore potential novel applications. In the present work microwave magnetoabsorption data of the annealed nickel ferrite nanoparticles are presented. These data have been obtained with a system based on a network analyzer that operates in the frequency range 0 - 8.5 GHz. At fields up to 400 mT we can observe a peak according to ferromagnetic resonance theory. Sample annealed at higher temperature exhibits different absorption, coercivity and saturation magnetization figures, revealing its multidomain character.
The Homeobox Gene Gsx2 Regulates the Self-Renewal and Differentiation of Neural Stem Cells and the Cell Fate of Postnatal Progenitors
Héctor R. Méndez-Gómez, Carlos Vicario-Abejón
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0029799
Abstract: The Genetic screened homeobox 2 (Gsx2) transcription factor is required for the development of olfactory bulb (OB) and striatal neurons, and for the regional specification of the embryonic telencephalon. Although Gsx2 is expressed abundantly by progenitor cells in the ventral telencephalon, its precise function in the generation of neurons from neural stem cells (NSCs) is not clear. Similarly, the role of Gsx2 in regulating the self-renewal and multipotentiality of NSCs has been little explored. Using retroviral vectors to express Gsx2, we have studied the effect of Gsx2 on the growth of NSCs isolated from the OB and ganglionic eminences (GE), as well as its influence on the proliferation and cell fate of progenitors in the postnatal mouse OB. Expression of Gsx2 reduces proliferation and the self-renewal capacity of NSCs, without significantly affecting cell death. Furthermore, Gsx2 overexpression decreases the differentiation of NSCs into neurons and glia, and it maintains the cells that do not differentiate as cycling progenitors. These effects were stronger in GESCs than in OBSCs, indicating that the actions of Gsx2 are cell-dependent. In vivo, Gsx2 produces a decrease in the number of Pax6+ cells and doublecortin+ neuroblasts, and an increase in Olig2+ cells. In summary, our findings show that Gsx2 inhibits the ability of NSCs to proliferate and self-renew, as well as the capacity of NSC-derived progenitors to differentiate, suggesting that this transcription factor regulates the quiescent and undifferentiated state of NSCs and progenitors. Furthermore, our data indicate that Gsx2 negatively regulates neurogenesis from postnatal progenitor cells.
Patterns and architecture of genomic islands in marine bacteria
Fernández-Gómez Beatriz,Fernàndez-Guerra Antonio,Casamayor Emilio O,González José M
BMC Genomics , 2012, DOI: 10.1186/1471-2164-13-347
Abstract: Background Genomic Islands (GIs) have key roles since they modulate the structure and size of bacterial genomes displaying a diverse set of laterally transferred genes. Despite their importance, GIs in marine bacterial genomes have not been explored systematically to uncover possible trends and to analyze their putative ecological significance. Results We carried out a comprehensive analysis of GIs in 70 selected marine bacterial genomes detected with IslandViewer to explore the distribution, patterns and functional gene content in these genomic regions. We detected 438 GIs containing a total of 8152 genes. GI number per genome was strongly and positively correlated with the total GI size. In 50% of the genomes analyzed the GIs accounted for approximately 3% of the genome length, with a maximum of 12%. Interestingly, we found transposases particularly enriched within Alphaproteobacteria GIs, and site-specific recombinases in Gammaproteobacteria GIs. We described specific Homologous Recombination GIs (HR-GIs) in several genera of marine Bacteroidetes and in Shewanella strains among others. In these HR-GIs, we recurrently found conserved genes such as the β-subunit of DNA-directed RNA polymerase, regulatory sigma factors, the elongation factor Tu and ribosomal protein genes typically associated with the core genome. Conclusions Our results indicate that horizontal gene transfer mediated by phages, plasmids and other mobile genetic elements, and HR by site-specific recombinases play important roles in the mobility of clusters of genes between taxa and within closely related genomes, modulating the flexible pool of the genome. Our findings suggest that GIs may increase bacterial fitness under environmental changing conditions by acquiring novel foreign genes and/or modifying gene transcription and/or transduction.
Shock Dynamics In Relativistic Jets
J. Cantó,S. Lizano,M. Fernández-López,R. F. González,A. Hernández-Gómez
Physics , 2013, DOI: 10.1093/mnras/stt072
Abstract: We present a formalism of the dynamics of internal shocks in relativistic jets where the source has a time-dependent injection velocity and mass-loss rate. The variation of the injection velocity produces a two-shock wave structure, the working surface, that moves along the jet. This new formalism takes into account the fact that momentum conservation is not valid for relativistic flows where the relativistic mass lost by radiation must be taken into account, in contrast to the classic regime. We find analytic solutions for the working surface velocity and radiated energy for the particular case of a step function variability of the injection parameters. We model two cases: a pulse of fast material and a pulse of slow material (with respect to the mean flow). Applying these models to gamma ray burst light curves, one can determine the ratio of the Lorentz factors gamma_2 / gamma_1 and the ratio of the mass-loss rates dot{m_2} / dot{m_1} of the upstream and downstream flows. As an example, we apply this model to the sources GRB 080413B and GRB 070318 and find the values of these ratios. Assuming a Lorentz factor gamma_1=100, we further estimate jet mass-loss rates between dot{m_1} ~ 10^{-5}-1 Msun.yr^{-1}. We also calculate the fraction of the injected mass lost by radiation. For GRB 070318 this fraction is ~7%. In contrast, for GRB 080413B this fraction is larger than 50%; in this case radiation losses clearly affect the dynamics of the internal shocks.
Compound stress response in stomatal closure: a mathematical model of ABA and ethylene interaction in guard cells
Mariano Beguerisse-D?az, Mercedes C Hernández-Gómez, Alessandro M Lizzul, Mauricio Barahona, Radhika Desikan
BMC Systems Biology , 2012, DOI: 10.1186/1752-0509-6-146
Abstract: Toshed light on this unexplained behaviour, we have collected time course measurements of stomatal aperture and hydrogen peroxide production in Arabidopsis thaliana guard cells treated with abscisic acid, ethylene, and a combination of both. Our experiments show that stomatal closure is linked to sustained high levels of hydrogen peroxide in guard cells. When treated with a combined dose of abscisic acid and ethylene, guard cells exhibit increased antioxidant activity that reduces hydrogen peroxide levels and precludes closure. We construct a simplified model of stomatal closure derived from known biochemical pathways that captures the experimentally observed behaviour.Our experiments and modelling results suggest a distinct role for two antioxidant mechanisms during stomatal closure: a slower, delayed response activated by a single stimulus (abscisic acid ‘or’ ethylene) and another more rapid ‘and’ mechanism that is only activated when both stimuli are present. Our model indicates that the presence of this rapid ‘and’ mechanism in the antioxidant response is key to explain the lack of closure under a combined stimulus.Stomata are tiny pores located mainly in the lower epidermis of plant leaves. Each stoma is formed by two guard cells attached to each other by their extremes. When the guard cells are turgid, due to their vacuoles being full of water, the pore opens (Figure 1A). When the vacuoles are emptied and water exits the cells, the guard cells become flaccid and the pore closes (Figure 1B) [1]. Loss of turgor pressure (and the resulting closure of the stomatal pore) is a consequence of the efflux of ions out of the cell. Ion efflux may be caused by a variety of stimuli including different light conditions and atmospheric carbon dioxide (CO2) levels, or signalling hormones such as abscisic acid (ABA) and ethylene [2,3]. Open pores allow the plant to absorb CO2 from the air to perform photosynthesis and to release oxygen and water into the atmosphere. If the por
The Laughter of Ticklishness Is a Darwinian Feature Related to Empathy in Both Genders: Self-Esteem in Men and Sexism in Women  [PDF]
Verónica Juárez-Ramos, Elvira Salazar-López, María ángeles Rodríguez Artacho, K. Chmielowiec, A. Riquelme, J. Fernández-Gómez, A. I. Fernández-Ramirez, A. Vicente de Haro, A. Miranda, M. Caballero, B. Machado, Antonio González Hernández, Emilio Gómez Milán
Open Journal of Medical Psychology (OJMP) , 2014, DOI: 10.4236/ojmp.2014.31002
Abstract: The theory of false alarm for laughter could explain the involuntary laugh when someone is tickled. To put this hypothesis to the test, we handed out a questionnaire (180 items) with two hundred university students. Our main results are: In women who like being tickled, we discover components related to pleasure, erotism, feeling of affection, arousal, uncontrollability, domination, sexism and Darwinian (golden ratio) and psychological traits (empathy, low schizotypy and external locus of control) that are not present in the laughter at a stumble. The relation of both types of laughter with sense of humor is also differential. In men who like being tickled, we discover components related to masturbation, sexual fantasies, erotism, arousal, domination, sexist humour and Darwinian (square chin, feeling of masculinity) and psychological traits (empathic stress, low schizotypy, external locus of control and overall self-esteem). The relationship between being tickled and self-esteem shows a double aspect in men: It is positive in men who like being tickled and negative in men who do not like being tickled. For women there is not a relationship between self-esteem and tickling. Our conclusion is that laughter of ticklishness is a Darwinian feature related to empathy.


The physical activity level of Mexican children decreases upon entry to elementary school
Jáuregui,Alejandra; Villalpando,Salvador; Rangel-Baltazar,Eduardo; Castro-Hernández,Jessica; Lara-Zamudio,Yaveth; Méndez-Gómez-Humarán,Ignacio;
Salud Pública de México , 2011, DOI: 10.1590/S0036-36342011000300007
Abstract: objective: to compare the physical activity patterns of a cohort of mexican children in kindergarten (k), first (1es) and second grade (2es) of elementary school. material and methods: the physical activity of 217 children (123 girls and 94 boys) aged 5-6 years was measured (five full-day triaxial accelerometry) annually.weekday and weekend moderate/ vigorous physical activity (mvpa) and school and off-school mvpa was calculated. comparisons between surveys were made using longitudinal multilevel generalized linear models. results: weekday mvpa was 22 and 37 min/d lower for 1es (p=0.06) and 2es (p<0.01), respectively, compared to k. school mvpa for 1es and 2es was 37 (-5.0 min/h) and 40% (-5.5 min/h) (p<0.001) lower, respectively, compared to k. no differences were found between weekend and off-school mvpa among school stages (p>0.5). conclusion: mvpa was significantly reduced from k to es,in part because of a decline in mvpa during school activities. interventions targeted to school environment modifications should be promoted.
Matrix Metalloproteinases and Bladder Cancer: What is New?
O. Rodriguez Faba,J. Palou-Redorta,J. M. Fernández-Gómez,F. Algaba
ISRN Urology , 2012, DOI: 10.5402/2012/581539
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