2,332 research outputs found
Fractional Schr\"odinger equation and time dependent potentials
We investigate the solutions for a time dependent potential by considering
two scenarios for the fractional Schr\"odinger equation. The first scenario
analyzes the influence of the time dependent potential in the absence of the
kinetic term. We obtain analytical and numerical solutions for this case by
considering the Caputo fractional time derivative, which extends Rabi's model.
In the second scenario, we incorporate the kinetic term in the Schr\"odinger
equation and consider fractional spatial derivatives. For this case, we analyze
the spreading of the Gaussian wave package under the action of the time and
spatial fractional differential operators
Maternal neurofascin-specific autoantibodies bind to structures of the fetal nervous system during pregnancy, but have no long term effect on development in the rat
Neurofascin was recently reported as a target for axopathic autoantibodies in patients with multiple sclerosis (MS), a response that will exacerbate axonal pathology and disease severity in an animal model of multiple sclerosis. As transplacental transfer of maternal autoantibodies can permanently damage the developing nervous system we investigated whether intrauterine exposure to this neurofascin-specific response had any detrimental effect on white matter tract development. To address this question we intravenously injected pregnant rats with either a pathogenic anti-neurofascin monoclonal antibody or an appropriate isotype control on days 15 and 18 of pregnancy, respectively, to mimic the physiological concentration of maternal antibodies in the circulation of the fetus towards the end of pregnancy. Pups were monitored daily with respect to litter size, birth weight, growth and motor development. Histological studies were performed on E20 embryos and pups sacrificed on days 2, 10, 21, 32 and 45 days post partum. Results: Immunohistochemistry for light and confocal microscopy confirmed passively transferred anti-neurofascin antibody had crossed the placenta to bind to distinct structures in the developing cortex and cerebellum. However, this did not result in any significant differences in litter size, birth weight, or general physical development between litters from control mothers or those treated with the neurofascin-specific antibody. Histological analysis also failed to identify any neuronal or white matter tract abnormalities induced by the neurofascin-specific antibody. Conclusions: We show that transplacental transfer of circulating anti-neurofascin antibodies can occur and targets specific structures in the CNS of the developing fetus. However, this did not result in any pre- or post-natal abnormalities in the offspring of the treated mothers. These results assure that even if anti-neurofascin responses are detected in pregnant women with multiple sclerosis these are unlikely to have a negative effect on their children
MAPfastR: Quantitative Trait Loci Mapping in Outbred Line Crosses
MAPfastR is a software package developed to analyze quantitative trait loci data from inbred and outbred line-crosses. The package includes a number of modules for fast and accurate quantitative trait loci analyses. It has been developed in the R language for fast and comprehensive analyses of large datasets. MAPfastR is freely available at: http://www.computationalgenetics.se/?page_id=7.Swedish Foundation for Strategic Research (Future Research Leader program), European Science Foundation (EURYI Award)
Ambiguity in a masculine world: Being a BRCA1/2 mutation carrier and a man with prostate cancer.
Objective Increased risk of prostate cancer (PCa) is observed in men with BRCA1/BRCA2 mutations. Sex and gender are key determinants of health and disease although unequal care exists between the sexes. Stereotypical male attitudes are shown to lead to poor health outcomes.Methods Men with BRCA1/2 mutations and diagnosed with PCa were identified and invited to participate in a qualitative interview study. Data were analysed using a framework approach. "Masculinity theory" was used to report the impact of having both a BRCA1/2 mutation and PCa.Results Eleven of 15 eligible men were interviewed. The umbrella concept of "Ambiguity in a Masculine World" was evident. Men's responses often matched those of women in a genetic context. Men's BRCA experience was described, as "on the back burner" but "a bonus" enabling familial detection and early diagnosis of PCa. Embodiment of PCa took precedence as men revealed stereotypical "ideal" masculine responses such as stoicism and control while creating new "masculinities" when faced with the vicissitudes of having 2 gendered conditions.Conclusion Health workers are urged to take a reflexive approach, void of masculine ideals, a belief in which obfuscates men's experience. Research is required regarding men's support needs in the name of equality of care
Predicting cell types and genetic variations contributing to disease by combining GWAS and epigenetic data
Genome-wide association studies (GWASs) identify single nucleotide polymorphisms (SNPs) that are enriched in individuals suffering from a given disease. Most disease-associated SNPs fall into non-coding regions, so that it is not straightforward to infer phenotype or function; moreover, many SNPs are in tight genetic linkage, so that a SNP identified as associated with a particular disease may not itself be causal, but rather signify the presence of a linked SNP that is functionally relevant to disease pathogenesis. Here, we present an analysis method that takes advantage of the recent rapid accumulation of epigenomics data to address these problems for some SNPs. Using asthma as a prototypic example; we show that non-coding disease-associated SNPs are enriched in genomic regions that function as regulators of transcription, such as enhancers and promoters. Identifying enhancers based on the presence of the histone modification marks such as H3K4me1 in different cell types, we show that the location of enhancers is highly cell-type specific. We use these findings to predict which SNPs are likely to be directly contributing to disease based on their presence in regulatory regions, and in which cell types their effect is expected to be detectable. Moreover, we can also predict which cell types contribute to a disease based on overlap of the disease-associated SNPs with the locations of enhancers present in a given cell type. Finally, we suggest that it will be possible to re-analyze GWAS studies with much higher power by limiting the SNPs considered to those in coding or regulatory regions of cell types relevant to a given disease
Factors associated with severe dry eye in primary Sjögren´s syndrome diagnosed patients
Introduction Primary Sjögren?s syndrome (pSS) is an autoimmune disease, characterized by lymphocytic infiltration of exocrine glands and other organs, resulting in dry eye, dry mouth and extraglandular systemic findings. Objective To explore the association of severe or very severe dry eye with extraocular involvement in patients diagnosed with primary Sjögren?s syndrome. Methods SJOGRENSER registry is a multicenter cross-sectional study of pSS patients. For the construction of our main variable, severe/very severe dry eye, we used those variables that represented a degree 3?4 of severity according to the 2007 Dry Eye Workshop classification. First, bivariate logistic regression models were used to identify the effect of each independent variable on severe/very severe dry eye. Secondly, multivariate analysis using regression model was used to establish the independent effect of patient characteristics. Results Four hundred and thirty-seven patients were included in SJOGRENSER registry; 94% of the patients complained of dry eye and 16% developed corneal ulcer. Schirmer?s test was pathological in 92% of the patients; 378 patients presented severe/very severe dry eye. Inflammatory articular involvement was significantly more frequent in patients with severe/very severe dry eye than in those without severe/very severe dry eye (82.5 vs 69.5%, p = 0,028). Inflammatory joint involvement was associated with severe/very severe dry eye in the multivariate analysis, OR 2.079 (95% CI 1.096?3.941). Conclusion Severe or very severe dry eye is associated with the presence of inflammatory joint involvement in patients with pSS. These results suggest that a directed anamnesis including systemic comorbidities, such as the presence of inflammatory joint involvement or dry mouth in patients with dry eye, would be useful to suspect a pSS
Efecto de los diluyentes Ley-Leygo y Triladyl y de dos tiempos de equilibrio en la congelación de semen de verraco
The aim of this study was to evaluate the effect of Ley-Leygo and Triladyl® extenders and two equilibrium times on individual motility (IM), plasma membrane integrity (PMI), mitochondrial activity (MA) and intact acrosome (IA) in frozen-thawed boar semen. A rich fraction of a total of 20 ejaculates from five boars of a commercial line was used. All ejaculates had a minimum of 80% motility and 85% normal spermatozoa. Each ejaculate was divided into four aliquots: Ley-Leygo and Triladyl® extenders and two equilibrium times (0 and 1 h). The semen samples were thawed at 37 °C for 20 s. The results of the IM and the PMI did not have significant effects for the factors evaluated (p>0.05). There was a significant difference for MA (p<0.05) between the Ley-Leygo (43.57%) and Triladyl® (51.7%) diluents. The IA was 46% for Ley-Leygo and 25% for Triladyl® (p<0.05). The percentage of IA with the equilibration time of 1 h was greater than that of 0 h (p<0.05). It is concluded that the Triladyl® diluent improved the MA and the equilibration time of 1 h improved the percentage of IA.El objetivo del estudio fue evaluar el efecto de los diluyentes Ley-Leygo y Triladyl® y de dos tiempos de equilibrio sobre la motilidad individual (MI), integridad de la membrana plasmática (IMP), actividad mitocondrial (AM) y acrosoma intacto (AI) del semen congelado-descongelado de cerdo. Se utilizó una fracción rica de un total de 20 eyaculados de cinco verracos de una lÃnea comercial, considerados aptos para la congelación con un mÃnimo de 80% de motilidad y 85% de espermatozoides normales. Cada eyaculado se dividió en cuatro alÃcuotas: diluyentes Ley-Leygo y Triladyl® y dos tiempos de equilibrio (0 y 1 h). Las muestras de semen se descongelaron a 37 °C durante 20 s. Los resultados de la MI y la IMP no tuvieron efectos significativos para los factores evaluados (p>0.05). Hubo diferencia significativa para la AM (p<0.05) entre los diluyentes de Ley- Leygo (43.57%) y Triladyl® (51.7%). El porcentaje de AI fue de 46% para Ley- Leygo y de 25% para Triladyl® (p<0.05). El porcentaje de AI con el tiempo de equilibrio de 1 h fue mayor que el de 0 h (p<0.05). Se concluye que el diluyente Triladyl® mejoró la AM y el tiempo de equilibrio de 1 h mejoró el porcentaje de AI
Effects of temperature on thick branes and the fermion (quasi-)localization
Following Campos's work [Phys. Rev. Lett. 88, 141602 (2002)], we investigate
the effects of temperature on flat, de Sitter (dS), and anti-de Following
Campos's work [Phys. Rev. Lett. \textbf{88}, 141602 (2002)], we investigate the
effects of temperature on flat, de Sitter (dS), and anti-de Sitter (AdS) thick
branes in five-dimensional (5D) warped spacetime, and on the fermion
(quasi-)localization. First, in the case of flat brane, when the critical
temperature reaches, the solution of the background scalar field and the warp
factor is not unique. So the thickness of the flat thick brane is uncertain at
the critical value of the temperature parameter, which is found to be lower
than the one in flat 5D spacetime. The mass spectra of the fermion Kaluza-Klein
(KK) modes are continuous, and there is a series of fermion resonances. The
number and lifetime of the resonances are finite and increase with the
temperature parameter, but the mass of the resonances decreases with the
temperature parameter. Second, in the case of dS brane, we do not find such a
critical value of the temperature parameter. The mass spectra of the fermion KK
modes are also continuous, and there is a series of fermion resonances. The
effects of temperature on resonance number, lifetime, and mass are the same
with the case of flat brane. Last, in the case of AdS brane, {the critical
value of the temperature parameter can less or greater than the one in the flat
5D spacetime.} The spectra of fermion KK modes are discrete, and the mass of
fermion KK modes does not decrease monotonically with increasing temperature
parameter.Comment: 24 pages, 15 figures, published versio
Liposomes as a model for the biological membrane : studies on daunorubicin bilayer interaction
In this study the interaction of the antitumoral drug daunorubicin with egg phosphatidylcholine (EPC) liposomes, used as a cell membrane model, was quantified by determination of the partition coefficient (Kp). The liposome/aqueous-phase Kp of daunorubicin was determined by derivative spectrophotometry and measurement of the zeta-potential. Mathematical models were used to fit the experimental data, enabling determination of Kp. In the partition of daunorubicin within the membrane both superficial electrostatic and inner hydrophobic interactions seem to be involved. The results are affected by the two types of interaction since spectrophotometry measures mainly hydrophobic interactions, while zeta-potential is affected by both interpenetration of amphiphilic charged molecules in the bilayer and superficial electrostatic interaction. Moreover, the degree of the partition of daunorubicin with the membrane changes with the drug concentration, due mainly to saturation factors. Derivative spectrophotometry and zeta-potential variation results, together with the broad range of concentrations studied, revealed the different types of interactions involved. The mathematical formalism applied also allowed quantification of the number of lipid molecules associated with one drug molecule
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