978 resultados para cornea: basic science
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Inspired by natural structures, great attention has been devoted to the study and development of surfaces with extreme wettable properties. The meticulous study of natural systems revealed that the micro/nano-topography of the surface is critical to obtaining unique wettability features, including superhydrophobicity. However, the surface chemistry also has an important role in such surface characteristics. As the interaction of biomaterials with the biological milieu occurs at the surface of the materials, it is expected that synthetic substrates with extreme and controllable wettability ranging from superhydrophilic to superhydrophobic regimes could bring about the possibility of new investigations of cellâ material interactions on nonconventional surfaces and the development of alternative devices with biomedical utility. This first part of the review will describe in detail how proteins and cells interact with micro/nano-structured surfaces exhibiting extreme wettabilities.
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Neural stem cells (NSCs) and mesenchymal stem cells (MSCs) share few characteristics apart from self-renewal and multipotency. In fact, the neurogenic and osteogenic stem cell niches derive from two distinct embryonary structures; while the later originates from the mesoderm, as all the connective tissues do, the first derives from the ectoderm. Therefore, it is highly unlikely that stem cells isolated from one niche could form terminally differentiated cells from the other. Additionally, these two niches are associated to tissues/systems (e.g., bone and central nervous system) that have markedly different needs and display diverse functions within the human body. Nevertheless they do share common features. For instance, the differentiation of both NSCs and MSCs is intimately associated with the bone morphogenetic protein family. Moreover, both NSCs and MSCs secrete a panel of common growth factors, such as nerve growth factor (NGF), glial derived neurotrophic factor (GDNF), and brain derived neurotrophic factor (BDNF), among others. But it is not the features they share but the interaction between them that seem most important, and worth exploring; namely, it has already been shown that there are mutually beneficially effects when these cell types are co-cultured in vitro. In fact the use of MSCs, and their secretome, become a strong candidate to be used as a therapeutic tool for CNS applications, namely by triggering the endogenous proliferation and differentiation of neural progenitors, among other mechanisms. Quite interestingly it was recently revealed that MSCs could be found in the human brain, in the vicinity of capillaries. In the present review we highlight how MSCs and NSCs in the neurogenic niches interact. Furthermore, we propose directions on this field and explore the future therapeutic possibilities that may arise from the combination/interaction of MSCs and NSCs.
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In the celebration of the Oswaldo Cruz Institute centenary, we wanted to stress our concern with the relationship between two of its missions: research and education. What are the educational bases required for science and technology activities on health sciences for the future years? How can scientists collaborate to promote the popularization of academic knowledge and to improve a basic education for citizenship in an ethic and humanistic view? In this article we pointed out to need of commitment, even in the biomedical post-graduation level, of a more integrated philosophy that would be centered on health education, assuming health as a dynamic biological and social equilibrium and emphasizing the need of scientific popularization of science in a cooperative construction way, instead of direct transfer of knowledge, preserving also macro views of health problems in the development of very specific studies. The contemporary explosion of knowledge, particularly biological knowledge, imposes a need of continuous education to face the growing illiteracy. In order to face this challenge, we think that the Oswaldo Cruz Institute honors his dialectic profile of tradition and transformation, always creating new perspectives to disseminate scientific culture in innovated forms.
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PURPOSE: When treating peripheral ectatic disease-like pellucid marginal degeneration (PMD), corneal cross-linking with UV-A and riboflavin (CXL) must be applied eccentrically to the periphery of the lower cornea, partly irradiating the corneal limbus. Here, we investigated the effect of standard and double-standard fluence corneal cross-linking with riboflavin and UV-A (CXL) on cornea and corneal limbus in the rabbit eye in vivo. METHODS: Epithelium-off CXL was performed in male New Zealand White rabbits with two irradiation diameters (7 mm central cornea, 13 mm cornea and limbus), using standard fluence (5.4 J/cm(2)) and double-standard fluence (10.8 J/cm(2)) settings. Controls were subjected to epithelial removal and riboflavin instillation, but were not irradiated with UV-A. Following CXL, animals were examined daily until complete closure of the epithelium, and at 7, 14, 21, and 28 days. Animals were killed and a corneoscleral button was excised and processed for light microscopy and immunohistochemistry. RESULTS: For both irradiation diameters and fluences tested, no signs of endothelial damage or limbal vessel thrombosis were observed, and time to re-epithelialization was similar to untreated controls. Histological and immunohistochemical analysis revealed no differences in the p63 putative stem cell marker expression pattern. CONCLUSIONS: Even when using fluence twice as high as the one used in current clinical CXL settings, circumferential UV-A irradiation of the corneal limbus does not alter the regenerative capacity of the limbal epithelial cells, and the expression pattern of the putative stem cell marker p63 remains unchanged. This suggests that eccentric CXL may be performed safely in PMD.
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As a thorough aggregation of probability and graph theory, Bayesian networks currently enjoy widespread interest as a means for studying factors that affect the coherent evaluation of scientific evidence in forensic science. Paper I of this series of papers intends to contribute to the discussion of Bayesian networks as a framework that is helpful for both illustrating and implementing statistical procedures that are commonly employed for the study of uncertainties (e.g. the estimation of unknown quantities). While the respective statistical procedures are widely described in literature, the primary aim of this paper is to offer an essentially non-technical introduction on how interested readers may use these analytical approaches - with the help of Bayesian networks - for processing their own forensic science data. Attention is mainly drawn to the structure and underlying rationale of a series of basic and context-independent network fragments that users may incorporate as building blocs while constructing larger inference models. As an example of how this may be done, the proposed concepts will be used in a second paper (Part II) for specifying graphical probability networks whose purpose is to assist forensic scientists in the evaluation of scientific evidence encountered in the context of forensic document examination (i.e. results of the analysis of black toners present on printed or copied documents).
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Iowa Department of Education surveyed Iowa’s 15 community colleges to gain information about each institution’s basic skill assessment requirements for placement into courses and programs. The survey asked what basic skill assessment(s) each institution uses, whether developmental course placement was mandatory, and what scores students needed to obtain to avoid being required or urged to take developmental courses in math, science, and reading. Additionally, staff members at each college were asked what the testing requirements are for students’ enrolled full time in high school that are taking community college classes.
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Over the past two decades, soil ecotoxicologists have made strides in utilizing the basic concepts and advancements in soil zoology and ecology. They have applied the existing tools, and developed new ones to investigate how chemical contamination can affect soil ecosystems, including the degradation or destruction of soil quality and habitats or the diminishment of belowground biodiversity. Soil ecotoxicologists are applying a suite of standard protocols, originally developed as laboratory tests with single chemicals (e.g., pesticides), and further enhancing both the approaches and protocols for the assessment of contaminated lands. However, ecological relevance of some approaches remains unresolved. The authors discuss the main challenges for a coherent ecotoxicological assessment of soil ecosystems amid contaminated lands, and provide recommendations on how to integrate the effects of physical and chemical soil properties, the variations in the diversity of soil invertebrates, and the interactions among organisms of various trophic levels. The review examines new international approaches and test methods using examples from three continents (in particular research conducted in Brazil), and provides recommendations for improving ecological relevance of ecotoxicological investigations of contaminated lands.
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Tutkielman tavoitteena on selvittää minkälaista kulttuurienvälistä kompetenssia Lappeenrannan teknillisestä yliopistosta vastavalmistuneilla kauppatieteenmaistereilla sekä diplomi-insinööreillä tulisi olla työnantajien näkökulmasta. Tutkimuksen tarkoituksena on myös tarkastella, että voidaanko kaikkia Lappeenrannan teknillisestä yliopistosta valmistuvia kutsua Kansainvälisiksi Huippuosaajiksi sekä kuinka Lappeenrannan teknillinen yliopisto voisi parantaa vastavalmistuvien kulttuurienvälistä kompetenssia. Teoreettinen osa tarkastelee kulttuurienvälisen kommunikaation tärkeimpiä elementtejä, kulttuurienvälistä kompetenssia ja vastavalmistuneiden kauppatieteenmaistereiden sekä diplomi-insinöörien tarvitsemaa ammatillista osaamista. Empiria koostuu kymmenen työnantajien teemahaastattelun tuloksista. Lopuksi johtopäätöksissä empirian tuloksia verrataan teorian löydöksiin. Tulokset osoittavat että kulttuurienvälinen kompetenssi koostuu kolmesta dimensiosta: henkilökohtaisista ominaisuuksista, tiedosta ja kommunikointikyvystä. Henkilökohtaisiin ominaisuuksiin sisältyvät empaattisuus, epävarmuuden sietokyky sekä avoin ja utelias asenne. Tieto - ulottuvuus koostuu yleisestä ja erityisestä kulttuuritiedosta, kielitaidosta sekä ammatillisesta osaamisesta. Kommunikointikykyyn puolestaan sisältyvät hyvät vuorovaikutustaidot. Työnantajat olettavat nykyään vastavalmistuneilla olevan ammatillisen osaamisen ja kielitaidon lisäksi, kulttuuritietoutta sekä kansainvälistä kokemusta. Lappeenrannan teknillinen yliopisto voisi parantaa vastavalmistuneiden kulttuurienvälistä kompetenssia tarjoamalla kulttuurienvälisen kommunikaation opetusta.
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Biotechnology has been recognized as the key strategic technology for industrial growth. The industry is heavily dependent on basic research. Finland continues to rank in the top 10 of Europe's most innovative countries in terms of tax-policy, education system, infrastructure and the number of patents issued. Regardless of the excellent statistical results, the output of this innovativeness is below acceptable. Research on the issues hindering the output creation has already been done and the identifiable weaknesses in the Finland's National Innovation system are the non-existent growth of entrepreneurship and the missing internationalization. Finland is proven to have all the enablers of the innovation policy tools, but is lacking the incentives and rewards to push the enablers, such as knowledge and human capital, forward. Science Parks are the biggest operator in research institutes in the Finnish Science and Technology system. They exist with the purpose of speeding up the commercialization process of biotechnology innovations which usually include technological uncertainty, technical inexperience, business inexperience and high technology cost. Innovation management only internally is a rather historic approach, current trend drives towards open innovation model with strong triple helix linkages. The evident problems in the innovation management within the biotechnology industry are examined through a case study approach including analysis of the semi-structured interviews which included biotechnology and business expertise from Turku School of Economics. The results from the interviews supported the theoretical implications as well as conclusions derived from the pilot survey, which focused on the companies inside Turku Science Park network. One major issue that the Finland's National innovation system is struggling with is the fact that it is technology driven, not business pulled. Another problem is the university evaluation scale which focuses more on number of graduates and short-term factors, when it should put more emphasis on the cooperation success in the long-term, such as the triple helix connections with interaction and knowledge distribution. The results of this thesis indicated that there is indeed requirement for some structural changes in the Finland's National innovation system and innovation policy in order to generate successful biotechnology companies and innovation output. There is lack of joint output and scales of success, lack of people with experience, lack of language skills, lack of business knowledge and lack of growth companies.
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When discussing the traditional and new missions of higher education (1996 Report to UNESCO of the International Commission on Education for the 21st Century) Jacques Delors stated that "Excessive attraction to social sciences has broken equilibrium of available graduates for workforce, thus causing doubts of graduates and employers on the quality of knowledge provided by higher education". Likewise, when discussing the progress of science and technology, the 1998 UNESCO World Conference on Higher Education concluded that "Another challenge concerts the latest advancements of Science, the sine qua non of sustainable development"; and that “with Information Technology, the unavoidable invasion of virtual reality has increased the distance between industrial and developing countries". Recreational Science has a long tradition all over the Educational World; it aims to show the basic aspects of Science, aims to entertain, and aims to induce thinking. Until a few years ago, this field of knowledge consisted of a few books, a few kits and other classical (yet innovative) ways to popularize the knowledge of Nature and the laws governing it. In Spain, the interest for recreational science has increased in the last years. First, new recreational books are being published and found in bookstores. Second the number of Science-related museums and exhibits is increasing. And third, new television shows are produced and new short science-based, superficial sketches are found in variety programs. However, actual programs in Spanish television dealing seriously with Science are scarce. Recreational Science, especially that related to physical phenomena like light or motion, is generally found at Science Museums because special equipment is required. On the contrary, Science related mathematics, quizzes and puzzles use to gather into books, e.g. the extensive collections by Martin Gardner. However, lately Science podcasts have entered the field of science communication. Not only traditional science journals and television channels are providing audio and video podcasts, but new websites deal exclusively with science podcasts, in particular on Recreational Science. In this communication we discuss the above mentioned trends and show our experience in the last two years in participating at Science Fairs and university-sponsored events to attract students to science and technology careers. We show a combination of real examples (e.g., mathemagic), imagination, use of information technology, and use of social networks. We present as well an experience on designing a computational, interactive tool to promote chemistry among high school, prospective students using computers ("Dancing with Bionanomolecules"). Like the concepts related to Web 2.0, it has been already proposed that a new framework for communication of science is emerging, i.e., Science Communication 2.0, where people and institutions develop new innovative ways to explain science topics to diverse publics – and where Recreational Science is likely to play a leading role
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In this class, we will discuss the course organization and provide a basic motivation for and introduction to the course. Readings: Web science: a provocative invitation to computer science, B. Shneiderman, Communications of the ACM 50 25--27 (2007) [Web link] Readings: Chapter 1 & 2, A Framework for Web Science, T. Berners-Lee and W. Hall and J. A. Hendler and K. O'Hara and N. Shadbolt and D. J. Weitzner Foundations and Trends® in Web Science 1 (2006) [Web link] Originally from: http://kmi.tugraz.at/staff/markus/courses/SS2008/707.000_web-science/
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The semantic web represents a current research effort to increase the capability of machines to make sense of content on the web. In this class, Peter Scheir will give a guest lecture on the basic principles underlying the semantic web vision, including RDF, OWL and other standards.
Evaluation of strategic knowledge of students through authentic tasks of writingin science classroom
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The difficulties at evaluating strategic knowledge have been connected to the use of deconxetualized tests that, at the end, do not involve the use of this knowledge. For this reason, an interest in developing authentic writing tasks that offer advantages for these kinds of evaluation have arisen. Throughout this research, authentic writing tasks were developed in a natural sciences class, with the purpose of evaluating the students' strategic knowledge. Different instruments were used to collect data, e.g. Interviews, questionnaires, a self-inform, as well as three samples of writing by the students, with the objective of analyzing the changes that occurred between one and the others, as well as to determine the decisions that students made in order to complete the assigned tasks successfully. An authentic writing task gives great opportunities to evaluate strategic knowledge. These tasks lead students to arrange their knowledge about the topic in hand, organize and adapt it to fit the objectives and the audience, also, it allows them to control and adjust their decisions on the task. This last stage became the perfect opportunity to take notes on the knowledge and regulation of cognitive processes that the students brought into play, as well as to evaluating their understanding of writing and the demands given on the different discursive genres. As a result, the students showed different degrees of strategic knowledge in the task. The students who showed a better strategic knowledge trust in their structural abilities know about discursive genres and have a good performance in basic linguistic abilities. The students who showed weak strategic knowledge distrust their writing skills, seem extremely worried about organizing the content of their texts, fail when checking their writings, and overlook or are unaware of the basic requirements of the discursive genre they are asked to exemplify. It appears that the previous knowledge and experiences at writing the students have been exposed to may affect the strategic knowledge shown when writing in this subject.
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Introducción: En la literatura, han aparecido reportes de neoplasia escamosa de superficie ocular (NESO) asociado con pterigio en un mismo paciente. Sin embargo, Colombia no cuenta con una estadística para ninguna de estas patologías. Objetivos: Determinar la frecuencia de NESO en pterigios resecados, en la Fundación Oftalmológica Nacional. Identificar factores de riesgo y características clínicas que predispongan a su aparición. Metodología: Estudio descriptivo de corte transversal. Se realizó una clasificación prequirúrgica y estudio histopatológico de los pterigios resecados en 93 pacientes, para confirmar su coexistencia con NESO. Se efectuó un análisis de frecuencias para datos demográficos y factores de riesgo asociados su aparición. Resultados: La frecuencia de NESO asociado a pterigio fue 7,07%. De estos, 28,5% identificados como sospechosos en la evaluación preoperatoria. La mayoría se presentaron en mujeres (71,4%), las ocupaciones con mayor frecuencia: labores domésticas (42,8%) y el comercio (28.5%). La exposición a derivados del petróleo y tabaquismo fue del 14,28%. No se presentaron casos asociados a infección por VIH. No hubo diferencias estadísticamente significativas sobre la presencia de NESO al comparar los casos en edad (p=0,8), procedencia (p=0,6) tabaquismo (p=0,4), leucoplaquia (p=1,0), queratinización (p=0,137), o vasos amputados (p=0,137). Conclusiones: De los pacientes con diagnóstico histopatológico de NESO, un porcentaje mínimo es sospechado clínicamente. Además se encontró este diagnóstico en pacientes más jóvenes que lo reportado en la literatura. Se recomienda realizar estudios con mayor número de pacientes para una mejor identificación de factores de riesgo. Palabras clave: