874 research outputs found
Single shot temporal measurement of short x-ray pulses using very fast photoconductive detectors
This report gives the status of the development of picosecond photoconductive detectors. The main application of these devices is the single shot temporal measurement of picosecond X-ray, U.V. or visible light pulses. We compare different materials, describe the X-ray autocorrelator and the single shot sampler developed by LETI/SCSI, Grenoble, France
Activation of the GLP-1 Receptor Signalling Pathway: A Relevant Strategy to Repair a Deficient Beta-Cell Mass
Recent preclinical studies in rodent models of diabetes suggest that exogenous GLP-1R agonists and DPP-4 inhibitors have the ability to increase islet mass and preserve beta-cell function, by immediate reactivation of beta-cell glucose competence, as well as enhanced beta-cell proliferation and neogenesis and promotion of beta-cell survival. These effects have tremendous implication in the treatment of T2D because they directly address one of the basic defects in T2D, that is, beta-cell failure. In human diabetes, however, evidence that the GLP-1-based drugs alter the course of beta-cell function remains to be found. Several questions surrounding the risks and benefits of GLP-1-based therapy for the diabetic beta-cell mass are discussed in this review and require further investigation
Facing Counterfeit Medications in Sexual Medicine. A Systematic Scoping Review on Social Strategies and Technological Solutions
Introduction: The counterfeit phenomenon is a largely under-reported issue, with potentially large burden for healthcare. The market for counterfeit drugs used in sexual medicine, most notably type 5 phosphodiesterase inhibitors (PDE5i), is rapidly growing.Aims: To report the health risks associated with the use of counterfeit medications, the reasons driving their use, and the strategies enacted to contain this phenomenon.Methods: A systematic scoping review of the literature regarding counterfeit PDE5i was carried between January and June 2021, then updated in August 2021.Main Outcome Measure: We primarily aimed to clarify the main drivers for counterfeit PDE5i use, the health risks associated, and the currently available strategies to fight counterfeiters.Results: One hundred thirty-one records were considered for the present scoping review. Production of fake PDE5i is highly lucrative and the lacking awareness of the potential health risks makes it a largely exploitable market by counterfeiters. Adulteration with other drugs, microbial contamination and unreliable dosages make counterfeit medications a cause of worry also outside of the sexual medicine scope. Several laboratory techniques have been devised to identify and quantify the presence of other compounds in counterfeit medications. Strategies aimed at improving awareness, providing antitampering packaging and producing non-falsifiable products, such as the orodispersible formulations, are also described.Clinical implications: Improving our understanding of the PDE5i counterfeit phenomenon can be helpful to promote awareness of this issue and to improve patient care.Strengths & Limitations: Despite the systematic approach, few clinical studies were retrieved, and data concerning the prevalence of counterfeit PDE5i use is not available on a global scale.Conclusion: The counterfeit phenomenon is a steadily growing issue, with PDE5i being the most counterfeited medication with potentially large harmful effects on unaware consumers. Copyright (C) 2021, International Society of Sexual Medicine. Published by Elsevier Inc
Review: Pancreatic β-Cell Neogenesis Revisited
β-cell neogenesis triggers the generation of new β-cells
from precursor cells. Neogenesis from duct epithelium is the
most currently described and the best documented process
of differentiation of precursor cells into β-cells. It is contributes
not only to β-cell mass expansion during fetal and
nonatal life but it is also involved in the maintenance of the
β-cell mass in adults. It is also required for the increase in
β-cell mass in situations of increase insulin demand (obesity,
pregnancy). A large number of factors controlling the differentiation
of β-cells has been identified. They are classified
into the following main categories: growth factors, cytokine
and inflamatory factors, and hormones such as PTHrP and
GLP-1. The fact that intestinal incretin hormone GLP-1
exerts a major trophic role on pancreatic β-cells provides
insights into the possibility to pharmacologically stimulate
β-cell neogenesis. This could have important implications
for the of treatment of type 1 and type 2 diabetes. Transdifferentiation,
that is, the differentiation of already differentiated
cells into β-cells, remains controversial.However, more
and more studies support this concept. The cells, which can
potentially “transdifferentiate” into β-cells, can belong to
the pancreas (acinar cells) and even islets, or originate from
extra-pancreatic tissues such as the liver. Neogenesis from intra-islet precursors also have been proposed and subpopulations
of cell precursors inside islets have been described
by some authors. Nestin positive cells, which have been considered
as the main candidates, appear rather as progenitors
of endothelial cells rather than β-cells and contribute to
angiogenesis rather than neogenesis. To take advantage of
the different differentiation processes may be a direction for
future cellular therapies. Ultimately, a better understanding
of the molecular mechanisms involved in β-cell neogenesis
will allow us to use any type of differentiated and/or undifferentiated
cells as a source of potential cell precursors
A basal ganglia inspired model of action selection evaluated in a robotic survival task.
The basal ganglia system has been proposed as a possible neural substrate for action selection in the vertebrate brain. We describe a robotic implementation of a model of the basal ganglia and demonstrate the capacity of this system to generate adaptive switching between several acts when embedded in a robot that has to "survive" in a laboratory environment. A comparison between this brain-inspired selection mechanism and classical "winner-takes-all" selection highlights some adaptive properties specific to the model, such as avoidance of dithering and energy-saving. These properties derive, in part, from the capacity of simulated basal ganglia-thalamo-cortical loops to generate appropriate "behavioral persistence"
Infância - educação e psicanálise: a (im)possibilidade de diálogo?!
O texto apresenta um breve histórico sobre o conceito de infância, tendo como referência pensadores como Ariès que caracteriza o infante como "não–falante", não existente. Destaca as transformações influenciadas pelos iluministas, em especial por Rousseau iniciando um processo de direito à fala, à palavra; e o infans para Lacan ocupando um lugar marcado pelo desejo materno, alienando-se na imagem de um Outro. Busca a relação entre psicanálise e educação, a necessidade do professor rever seus conceitos e postura ética para se utilizar dos conhecimentos psicanalíticos em sua prática educativa, num encontro com as diferenças, sendo o conhecimento o objeto de desejo que circula entre professor e aluno e a subjetividade dessa relação entre professor-aluno-conhecimento. Traz a discussão sob a perspectiva do sujeito "que não aprende", que é "des" qualquer coisa, "des-interessado, des-motivado" e no endereçamento ao professor que é um suposto-saber. Defende uma educação que pensa em "sujeitos" e não em "massas uniformizadas" dentro de uma sala de aula, que respeite a singularidade de cada aluno, apesar do constrangimento e insegurança gerados pelo convívio com as diferenças. Reflete sobre a escola enquanto instituição normativa e a importância da construção do trabalho em grupo.The text presents a historical briefing about infancy concept, having as reference philosophers, such as Ariès that describe infant as "non-talker", does not existing. It shows the transformations influenced by the illuminists, in special Rousseau initiating a process of right to the speech, the word and infants for Lacan occupying a place marked for the maternal desire, becoming alienated of one image to Another one. It search’s the relation between psychoanalysis and education, the necessity of the professor to review its concepts and ethical position to use itself of the psychoanalysis knowledge in educative practical its, in a meeting with the differences, being the knowledge the desire object that circulates between professor and pupil and in the subjectivity of this relation between professor-pupil-knowledge. It brings the quarrel under the perspective of the citizen "does not learn" that any thing is "not-interested, not-motivated" and addressing to the professor who is the presumption of knowledge. It defends an education that thinks about "citizens" and not in "group of people" inside of a classroom, that respects the singularity of each pupil, although the constrain and insecurity generated by the relationship with the differences. It reflects on the school as a normative institution and in the importance of the construction of the work in-group
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