Fluorescence Microscopy Imaging Denoising with Log-Euclidean Priors and Photobleaching Compensation

Fluorescent protein microscopy imaging is nowadays one of the most important tools in biomedical research. However, the resulting images present a low signal to noise ratio and a time intensity decay due to the photobleaching effect. This phenomenon is a consequence of the decreasing on the radiation emission efficiency of the tagging protein. This occurs because the fluorophore permanently loses its ability to fluoresce, due to photochemical reactions induced by the incident light. The Poisson multiplicative noise that corrupts these images, in addition with its quality degradation due to photobleaching, make long time biological observation processes very difficult. In this paper a denoising algorithm for Poisson data, where the photobleaching effect is explicitly taken into account, is described. The algorithm is designed in a Bayesian framework where the data fidelity term models the Poisson noise generation process as well as the exponential intensity decay caused by the photobleaching. The prior term is conceived with Gibbs priors and log-Euclidean potential functions, suitable to cope with the positivity constrained nature of the parameters to be estimated. Monte Carlo tests with synthetic data are presented to characterize the performance of the algorithm. One example with real data is included to illustrate its application.

Changes in nuclear morphology and chromatin texture of basal keratinocytes in melasma

BackgroundThe pathogenesis of melasma and the role of keratinocytes in disease development and maintenance are not completely understood. Dermal abnormalities, the expression of inflammatory mediators, growth factors, epithelial expression of melanocortin and sexual hormones receptors suggest that not only melanocytes, but entire epidermal melanin unit is involved in melasma physiopathology.ObjectivesTo compare nuclear morphological features and chromatin texture between basal keratinocytes in facial melasma and adjacent normal skin.MethodsWe took facial skin biopsies (2mm melasma and adjacent normal skin) from women processed for haematoxylin and eosin. Thirty non-overlapping basal keratinocyte nuclei were segmented and descriptors of area, highest diameter, perimeter, circularity, pixel intensity, profilometric index (Ra) and fractal dimension were extracted using ImageJ software.ResultsBasal keratinocyte nuclei from facial melasma epidermis displayed larger size, irregular shape, hyperpigmentation and chromatin heterogeneity by fractal dimension than perilesional skin.ConclusionBasal keratinocytes from facial melasma display changes in nuclear form and chromatin texture, suggesting that the phenotype differences between melasma and adjacent facial skin can result from complete epidermal melanin unit alterations, not just hypertrophic melanocytes.

Impact of comorbid migraine on the clinical course of bipolar disorder

Background: Recent evidence suggests an association between migraine and bipolar disorder (BD), although the impact of this association in the clinical course of BD is relatively unknown. Objective: This study aimed to compare 2 groups of individuals with BD (with vs without comorbid migraine) and evaluate differences in severity of clinical course. Methods: Three hundred thirty-nine adults with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition defined bipolar or II disorder were enrolled and divided into 2 groups: with and without comorbid migraine. Demographic and clinical data were obtained using standardized interviews. Results: Patients with comorbid migraines had more mood episodes, especially those with depressive polarity. In addition, comorbid migraine was associated with a higher prevalence of psychiatric and general medical comorbidities. Differences between the 2 groups in number of lifetime hospitalizations for depression/mania, rates of rapid cycling, and history of suicide attempts were not observed after Bonferroni correction. Conclusions: Comorbid migraine seems to be associated with poor outcomes in BD. Additional studies should be conducted to investigate shared vulnerabilities and pathophysiologic mechanisms as well as treatment optimization of both illnesses. (C) 2012 Elsevier Inc. All rights reserved.

Pliocene-Pleistocene stack of globally distributed benthic stable oxygen isotope records

We present a 5.3-Myr stack (the ''LR04'' stack) of benthic d18O records from 57 globally distributed sites aligned by an automated graphic correlation algorithm. This is the first benthic delta18O stack composed of more than three records to extend beyond 850 ka, and we use its improved signal quality to identify 24 new marine isotope stages in the early Pliocene. We also present a new LR04 age model for the Pliocene-Pleistocene derived from tuning the delta18O stack to a simple ice model based on 21 June insolation at 65 N. Stacked sedimentation rates provide additional age model constraints to prevent overtuning. Despite a conservative tuning strategy, the LR04 benthic stack exhibits significant coherency with insolation in the obliquity band throughout the entire 5.3 Myr and in the precession band for more than half of the record. The LR04 stack contains significantly more variance in benthic delta18O than previously published stacks of the late Pleistocene as the result of higher resolution records, a better alignment technique, and a greater percentage of records from the Atlantic. Finally, the relative phases of the stack's 41- and 23-kyr components suggest that the precession component of delta18O from 2.7-1.6 Ma is primarily a deep-water temperature signal and that the phase of d18O precession response changed suddenly at 1.6 Ma.

Io. Gottlieb Heineccii... Operum tomus sextus quo continentir I. Elementa iuris ciuilis secundum ordinem Pandectarum, II. Obseruationes theoretico-practicae ad Pandectas.

Grabado xilográfico en la portada.

Theses hebraeo-philologicae

Invocatio: I.N.J.

Decreto rectoral No. 809 : Por el cual se adopta el Reglamento Académico de Postgrados Médico Quirúrgicos de la Facultada de Medicina del Colegio Mayor de Nuestra Señora del Rosario

Por el cual se adopta el Reglamento Académico de Postgrados Médico Quirúrgicos de la Facultada de Medicina del Colegio Mayor de Nuestra Señora del Rosario.

Decreto rectoral No. 839 : Que es necesario modificar algunos artículos del Reglamento Académico Postgrados Médico Quirúrgicos, decreto rectoral número 809 del 10 de mayo de 2004

Que es necesario modificar algunos artículos del Reglamento Académico Postgrados Médico Quirúrgicos, decreto rectoral número 809 del 10 de mayo de 2004.

Servidores públicos del estado con especial protección constitucional. Políticas de prevención del daño antijurídico en relación con su retiro del servicio

El retiro del servicio de los empleados públicos aparece como una facultad reglada en las normas del empleo público que, cuando se da alguna de las hipótesis legales que lo hacen procedente, facultan al nominador para ejercer sus atribuciones legales, persiguiendo, ante todo, razones del servicio: su mejora, renovación, eficiencia y moralidad, entre otras. A partir del concepto de una buena administración del Estado, establecer la procedencia y elementos estructurales de una política de prevención del daño antijurídico en relación con el retiro del servicio de servidores públicos que, conforme al ordenamiento jurídico gozan de una especial protección constitucional. Conocer el concepto, el alcance, la regulación y desarrollo jurisprudencial de esta trascendental atribución para el servicio público, resulta indispensable para la debida aplicación del derecho, del ejercicio de las atribuciones públicas por parte de la Administración, y para la prevención del daño antijurídico.