40 research outputs found
Impactos potenciais do fenômeno "fuga de cérebros" no desenvolvimento econômico, científico e tecnológico do Brasil
Orientador: Profa. Dra. Carolina BagattolliMonografia (graduação) - Universidade Federal do Paraná, Setor de Ciências Sociais Aplicadas, Curso de Ciências EconômicasInclui referênciasResumo : Aspectos como tecnologia e inovação integram um processo indutor de crescimento que tem na sua base o capital humano. Profissionais altamente qualificados possuem competências e conhecimentos tácitos fundamentais para o desenvolvimento social e econômico de uma nação. Nesse contexto, a emigração em massa desses indivíduos pode causar desequilíbrios e prejudicar perspectivas de crescimento e produtividade, esse fenômeno é conhecido como "fuga de cérebros". Embora seja uma preocupação também para os países desenvolvidos, a fuga de cérebros é vista como uma séria restrição ao progresso de países emergentes, como é o caso do Brasil. Na conjuntura vigente, o número de profissionais altamente qualificados deixando o país tem aumentado desde 2016, esses deslocamentos podem provocar efeitos significativos para o desenvolvimento futuro do Brasil. Desse modo, o presente estudo objetivou identificar os principais impactos, tanto positivos quanto negativos, que o mais recente movimento de fuga de cérebros brasileiros pode gerar no desenvolvimento econômico, científico e tecnológico de um país emergente como o Brasil, com base na literatura vigente sobre o tema. Para tal propósito, a metodologia utilizada baseou-se na pesquisa bibliográfica e na revisão integrativa de literatura. Ao longo da pesquisa foram analisados os conceitos teóricos desenvolvidos pelos estudiosos da temática, bem como o histórico da ocorrência do fenômeno no país, a dinâmica de atração e retenção de jovens de países emergentes para os países da OCDE, o cenário recente de cortes orçamentários em ciência e tecnologia no Brasil e as políticas públicas que podem ser colocadas em prática no intuito de atenuar os impactos negativos e explorar os possíveis benefícios do fenômeno, levando em consideração as características específicas do Brasil e a experiência vivenciada por outros países emergentes, como China e Índia. Em relação aos efeitos positivos, a literatura destaca os seguintes impactos: (1) Regresso do indivíduo mais bem capacitado; (2) Recebimento de remessas financeiras; (3) Redes de networking internacionais e diásporas intelectuais e (4) Diminuição do desemprego. No que se refere aos efeitos negativos, três impactos principais foram identificados: (1) Perda de
capital humano intelectual; (2) Escassez de inovação e tecnologias disruptivas e (3) Aumento da desigualdade entre centro e periferia
The subgenomic promoter of brome mosaic virus folds into a stem-loop structure capped by a pseudo-triloop that is structurally similar to the triloop of the genomic promoter
Supramolecular & Biomaterials Chemistr
Prevalência de lesões em atletas da seleção brasileira de taekwondo
Objetivo: Identificar a prevalência de lesões em atletas adultos da seleção brasileira masculina de taekwondo. Métodos: Onze atletas com idade média de 24±4,5 anos responderam dois questionários semiestruturados e questões objetivas para investigação dos seguintes aspectos: idade; tempo de prática; graduação; região anatômica afetada em treinos e competições; mecanismos de lesão durante campeonato e treinamento; periodização; duração e frequência de treinos e competições no último ano; e se houve interrupção da prática de taekwondo decorrente das lesões. Resultados: A contusão foi o tipo mais frequente e os membros inferiores os mais acometidos; 27% relataram interrupção do treinamento maior ou igual a 1 dia de treino e/ou competição, em decorrência das lesões. A frequência média de competições; frequência semanal de treinamento e meses de treinamento por ano foram: 6±3 vezes/ano; 5±1 dias/semana e 10±3 meses/ano. Conclusão: A lesão mais prevalente dos atletas da seleção brasileira de taekwondo foi a contusão na coxa e no antebraço decorrente de golpe do adversário durante campeonatos.
ABSTRACT. Injurie’s prevalence in athletes of the Brazilian national team of taekwondo. Objective: Identify the prevalence of injuries in male adults’ athletes of the Brazilian team of taekwondo. Methods: Eleven athletes aged 24±4.5 years answered two semi-structured questionnaires and questions for investigation of the following aspects: age; time practicing; taekwondo’s graduation; anatomical region injured during training and/or competitions; injury mechanisms during competitions and training; periodization; duration and frequency of training and competitions in the last year; and if there was interruption of taekwondo practice due to injuries. Results: The contusion was the most frequent injury, and the lower limbs were most affected, 27% reported discontinuation of training and/or competition greater than or equal to 1 day due to injuries. The mean frequency of competitions; training days per week and training months per year were: 6±3 times/year; 5±1 days/week and 10±3 months/year. Conclusion: The most prevalent injury of athletes from the Brazilian team of taekwondo was the contusion in the thigh and forearm during competitions
Newly characterized interaction stabilizes DNA structure: oligoethylene glycols stabilize G-quadruplexes CH–π interactions
Oligoethylene glycols are used as crowding agents in experiments that aim to understand the effects of intracellular environments on DNAs. Moreover, DNAs with covalently attached oligoethylene glycols are used as cargo carriers for drug delivery systems. To investigate how oligoethylene glycols interact with DNAs, we incorporated deoxythymidine modified with oligoethylene glycols of different lengths, such as tetraethylene glycol (TEG), into DNAs that form antiparallel G-quadruplex or hairpin structures such that the modified residues were incorporated into loop regions. Thermodynamic analysis showed that because of enthalpic differences, the modified G-quadruplexes were stable and the hairpin structures were slightly unstable relative to unmodified DNA. The stability of G-quadruplexes increased with increasing length of the ethylene oxides and the number of deoxythymidines modified with ethylene glycols in the G-quadruplex. Nuclear magnetic resonance analyses and molecular dynamics calculations suggest that TEG interacts with bases in the G-quartet and loop via CH-pi and lone pair-pi interactions, although it was previously assumed that oligoethylene glycols do not directly interact with DNAs. The results suggest that numerous cellular co-solutes likely affect DNA function through these CH-pi and lone pair-pi interactions
Solution-state structure of a fully alternately 2′-F/2′-OMe modified 42-nt dimeric siRNA construct
A high-resolution solution structure of a stable 42-nt RNA dimeric construct has been derived based on a high number of NMR observables including nuclear overhauser effects (NOEs), J-coupling constants and residual dipolar couplings (RDCs), which were all obtained with isotopically unlabeled molecules. Two 21-nt siRNA that efficiently hybridize consist of ribose units that were alternately substituted by 2′-fluoro or 2′-methoxy groups. Structure calculations utilized a set of H-F RDC values for all 21 2′-fluoro modified nucleotides under conditions of weak alignment achieved by Pf1 phages. A completely 2′-F/2′-OMe modified dimeric RNA construct adopts an antiparallel double-helical structure consisting of 19 Watson–Crick base pairs with additional 3′ UU overhangs and a 5′ phosphate group on the antisense strand. NMR data suggest that the stability of individual base pairs is not uniform throughout the construct. While most of the double helical segment exhibits well dispersed imino resonances, the last three base pairs either display uncharacteristic chemical shifts of imino protons or absence of imino resonances even at lower temperatures. Accessibility of imino protons to solvent exchange suggests a difference in stability of duplex ends, which might be of importance for incorporation of the guide siRNA strand into a RISC
SINEUP non-coding RNAs rescue defective frataxin expression and activity in a cellular model of Friedreich's Ataxia
Friedreich's ataxia (FRDA) is an untreatable disorder with neuro- and cardio-degenerative progression. This monogenic disease is caused by the hyper-expansion of naturally occurring GAA repeats in the first intron of the FXN gene, encoding for frataxin, a protein implicated in the biogenesis of iron-sulfur clusters. As the genetic defect interferes with FXN transcription, FRDA patients express a normal frataxin protein but at insufficient levels. Thus, current therapeutic strategies are mostly aimed to restore physiological FXN expression. We have previously described SINEUPs, natural and synthetic antisense long non-coding RNAs, which promote translation of partially overlapping mRNAs through the activity of an embedded SINEB2 domain. Here, by in vitro screening, we have identified a number of SINEUPs targeting human FXN mRNA and capable to up-regulate frataxin protein to physiological amounts acting at the post-transcriptional level. Furthermore, FXN-specific SINEUPs promote the recovery of disease-associated mitochondrial aconitase defects in FRDA-derived cells. In summary, we provide evidence that SINEUPs may be the first gene-specific therapeutic approach to activate FXN translation in FRDA and, more broadly, a novel scalable platform to develop new RNA-based therapies for haploinsufficient diseases
Insight into G-DNA Structural Polymorphism and Folding from Sequence and Loop Connectivity through Free Energy Analysis
Stability and kinetics of G-quadruplex structures
In this review, we give an overview of recent literature on the structure and stability of unimolecular G-rich quadruplex structures that are relevant to drug design and for in vivo function. The unifying theme in this review is energetics. The thermodynamic stability of quadruplexes has not been studied in the same detail as DNA and RNA duplexes, and there are important differences in the balance of forces between these classes of folded oligonucleotides. We provide an overview of the principles of stability and where available the experimental data that report on these principles. Significant gaps in the literature have been identified, that should be filled by a systematic study of well-defined quadruplexes not only to provide the basic understanding of stability both for design purposes, but also as it relates to in vivo occurrence of quadruplexes. Techniques that are commonly applied to the determination of the structure, stability and folding are discussed in terms of information content and limitations. Quadruplex structures fold and unfold comparatively slowly, and DNA unwinding events associated with transcription and replication may be operating far from equilibrium. The kinetics of formation and resolution of quadruplexes, and methodologies are discussed in the context of stability and their possible biological occurrence
De invloed van de ruwheid van translerende, elastomere afdichtingen op lekkage en wrijving
Mesure optique de paramètres thermodynamiques et production de radicaux dans des micro-écoulements cavitants
A constriction in the microchannel can be used to establish a two-phase flow, when a sufficient liquid flux is introduced. This is known as hydrodynamic cavitation. The latent heat resulting from the growing and collapsing vapor bubbles makes it interesting to observe the temperature conditions in the flow downstream of the constriction. Using fluorescence microscopy, with the addition of temperature sensitive nano probes into the working fluid, we can determine the temperature at a single point, averaged over the integration time. Coupled with a confocal microscope, we were able to produce two and three dimensional temperature maps of the steady state flow in the microchannel by the use of ratiometric intensity measurements. This technic allows us to observe temperature gradients in two-phase flow as well yielding the void fraction information. Areas of substantial cooling are observed downstream the constriction in the two-phase flow, linked to the bubble growth, while heating regions due to condensations are missing. A complementary, yet less sensitive probe-less technique using the inherent Raman scattering signal of the liquid, was used to confirm the findings. A separate study evaluating a new group of luminescent materials for optical temperature and pressure probes is performed and discussed herein. Finally, the luminol chemiluminescent reaction with radicals produced by the cavitating flow, is used to obtain a corresponding photon yield. By counting the photons produced, an estimate on the radical yield can be obtained. Additionally, rudimentary mapping of the chemiluminescence signal allows the localization of the bubble collapse regionsUne zone de constriction dans un micro-canal fluidique peut générer, si le débit est suffisant, un écoulement bi-phasique. Ceci est l’origine de la cavitation hydrodynamique. Les échanges de chaleur latente générés par l’apparition et l’implosion des bulles impliquent une variabilité importante de la température dans les zones au-delà de la constriction. En ajoutant des sondes de température nanométriques dans le fluide et en utilisant un microscope confocal on peut déterminer la température en un point. Ainsi on a pu établir des cartographies thermiques en 2 et 3 dimensions à l’intérieur d’un écoulement stationnaire bi-phasique. La technique permet en outre d’avoir accès à la quantité de gaz ce qui permet de corréler les gradients de température avec les zones de transitions de phases. Des zones de très forts refroidissements sont observées après la constriction, là où les bulles apparaissent. Par contre on n’observe pas les zones d’échauffement attendu à cause de la condensation. Une méthode complémentaire, moins sensible, utilisant la spectroscopie Raman a aussi été utilisée pour confirmer ce résultat. Par ailleurs une nouvelle classe de matériaux luminescents sensible à la température et la pression a été étudiée. Enfin une étude de la production de radicaux lors de l’implosion des bulles a été menée en utilisant la chimiluminescence du luminol. La technique utilisée par comptage de photons a permis de quantifier cette production et une cartographie de l’émission du luminol a permis d’associer celle-ci avec la zone d’implosion des bulle