Induced pluripotent stem cells, a giant leap for mankind therapeutic applications

Induced pluripotent stem cells (iPSC) technology has propelled the field of stem cells biology, providing new cells to explore the molecular mechanisms of pluripotency, cancer biology and aging. A major advantage of human iPSC, compared to the pluripotent embryonic stem cells, is that they can be generated from virtually any embryonic or adult somatic cell type without destruction of human blastocysts. In addition, iPSC can be generated from somatic cells harvested from normal individuals or patients, and used as a cellular tool to unravel mechanisms of human development and to model diseases in a manner not possible before. Besides these fundamental aspects of human biology and physiology that are revealed using iPSC or iPSC-derived cells, these cells hold an immense potential for cell-based therapies, and for the discovery of new or personalized pharmacological treatments for many disorders. Here, we review some of the current challenges and concerns about iPSC technology. We introduce the potential held by iPSC for research and development of novel health-related applications. We briefly present the efforts made by the scientific and clinical communities to create the necessary guidelines and regulations to achieve the highest quality standards in the procedures for iPSC generation, characterization and long-term preservation. Finally, we present some of the audacious and pioneer clinical trials in progress with iPSC-derived cells.info:eu-repo/semantics/publishedVersio

The double dipole model of theta rhythm generation: Simulation of laminar field potential profiles in dorsal hippocampus of the rat

A set of compartmental models of CA1 pyramidal, granular and polymorph cells of the dorsal hippocampus have been used to simulate membrane potentials generated by synaptic activation at various levels along these cells. From the membrane potential distributions the field potentials in dorsal CA1 and the dorsal blade of the dentate area have been simulated using a model based on volume conduction theory. Field potential profiles similar to laminar profiles, found experimentally in the dorsal hippocampus during theta rhythm, could only be simulated by assuming (almost) simultaneous synaptic excitation of the 3 cell types at given sites. The results lead to 2 alternative models for the simultaneous excitation of CA1 pyramidal cells and dentate granular cells during theta rhythm. Other electrophysiological evidence favours the model in which the two neuronal populations are activated distally near the fissure

Situação formativa : um instrumento de gestão do currículo capaz de promover literacia científica

Com este trabalho pretende-se apresentar os resultados obtidos na primeira fase de um estudo que visa conhecer as potencialidades do instrumento de planificação e gestão curricular “Situação Formativa” para promover, em dois grupos de professores do Ensino Básico (um em inicio de carreira e outro com cerca de 11 anos de serviço), percepções adequadas sobre a Ciência, a Tecnologia e suas relações com a Sociedade (CTS). Para além do enquadramento do trabalho, apresentam-se a metodologia e os instrumentos adoptados, exemplo de dados recolhidos e sua análise, bem como algumas conclusões

Contexts for questioning: Two zones of teaching and learning in undergraduate science

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Springer Science+Business Media B.V. 2012.Higher education institutions are currently undertaking a challenging process in moving from teacher-orientated to student-focused approaches. Students’ ability to asking questions is fundamental to developing critical reasoning, and to the process of scientific enquiry itself. Our premise is that questioning competences should become a central focus of current reforms in higher education. This study, part of a broader naturalistic research project, aims at developing a theoretical framework for conceptualizing different contexts for questioning, illustrating the application of the proposed framework (contextual questioning zones) and reflecting about some of the dimensions of teaching and learning, for overcoming some of the challenges that higher education institutions are facing presently. The discussion of two ‘opposite’ contexts of enquiry is based on qualitative data, gathered through close collaboration with four teachers of undergraduate biology at a Portuguese university. These teachers were observed during their ‘daily activity’ during an academic year. Data was also gathered by interviewing these teachers and 8 selected students, at the end of the year, and used to sustain the argumentation. The paper concludes with some reflections and suggestions to promote authentic enquiry-based learning experiences.Portuguese Fundação para a Ciência e a Tecnologi

Non-Gaussian velocity distributions - The effect on virial mass estimates of galaxy groups

We present a study of 9 galaxy groups with evidence for non-Gaussianity in their velocity distributions out to 4R200. This sample is taken from 57 groups selected from the 2PIGG catalog of galaxy groups. Statistical analysis indicates that non-Gaussian groups have masses significantly higher than Gaussian groups. We also have found that all non-Gaussian systems seem to be composed of multiple velocity modes. Besides, our results indicate that multimodal groups should be considered as a set of individual units with their own properties. In particular, we have found that the mass distribution of such units are similar to that of Gaussian groups. Our results reinforce the idea of non-Gaussian systems as complex structures in the phase space, likely corresponding to secondary infall aggregations at a stage before virialization. The understanding of these objects is relevant for cosmological studies using groups and clusters through the mass function evolution.Comment: 5 pages, 4 figures and 2 tables. Accepted for publication in the MNRA

Pulsating Spectrum of Subdwarf Star PG 1605+072: Comparative Time-Frequency Analysis via Wavelet Packet and Local Sine Packet Transforms of an Interrupted Light Curve

We present the time-frequency analysis of an interrupted light-curve time series of the pulsating subdwarf B (sdB) star PG 1605+072. From the data of a eight-night observational run we have determined the pulsating spectrum of PG 1605+072. We used both wavelet packet transform (WPTs) and localized sine packet transform (LSPTs) analysis to compare frequency determinations with previous results based on Fourier methods and their typical modeling of signals by strictly harmonic contributions. The procedures adopted here allow the determination of the pulsating spectrum of the combined night runs of data with a reduction of the usual alias peaks produced by the daytime observing gaps, thus providing a clean and compact spectrum. We also use various compression techniques to study signal reconstruction under WPT

Unfriendly customer behaviors and employees’ psychological capital: the role of health symptoms and positive humor events

This study examined the indirect effect and moderators that may explain the link between unfriendly customer behaviors and workers’ psychological capital with a sample of 380 employees. We hypothesized that perceived health symptoms would have an indirect effect on the link between unfriendly customer behaviors and psychological capital. We also hypothesized a moderated mediation model, in which positive humor events would moderate the indirect effect. Results show that the negative association between unfriendly customer behaviors with psychological capital was due to an increased level of perceived health symptoms. Moreover, positive humor events moderated the link between unfriendly customer behaviors and perceived health symptoms, such that the link was stronger when the frequency of positive humor events was low to moderate. This study addresses a major gap in the positive psychology literature by attempting to examine why unfriendly customer behaviors relate to decreased psychological capital and what factors influence in this relation. Practical implications are further discussed.info:eu-repo/semantics/acceptedVersio

Performing edge detection by difference of Gaussians using q-Gaussian kernels

In image processing, edge detection is a valuable tool to perform the extraction of features from an image. This detection reduces the amount of information to be processed, since the redundant information (considered less relevant) can be unconsidered. The technique of edge detection consists of determining the points of a digital image whose intensity changes sharply. This changes are due to the discontinuities of the orientation on a surface for example. A well known method of edge detection is the Difference of Gaussians (DoG). The method consists of subtracting two Gaussians, where a kernel has a standard deviation smaller than the previous one. The convolution between the subtraction of kernels and the input image results in the edge detection of this image. This paper introduces a method of extracting edges using DoG with kernels based on the q-Gaussian probability distribution, derived from the q-statistic proposed by Constantino Tsallis. To demonstrate the method's potential, we compare the introduced method with the traditional DoG using Gaussians kernels. The results showed that the proposed method can extract edges with more accurate details.Comment: 5 pages, 5 figures, IC-MSQUARE 201