940 resultados para Printing in three-dimensional imaging


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Objective: Determine the presence of"burnout" syndrome and characteristic personality patterns in the students and faculty of three graduate programs in Dentistry at the University of Barcelona: Department of Oral Surgery and Implantology, Department of Orthodontics and Department of Integrated Dentistry. Materials and Methods: The study was carried out in 78 dentists. The level of"burnout" was evaluated using the Maslach Burnout Inventory, socio-demographic variables and, finally, the personality test. Results: Oral surgeons constituted the group of highlevel"burnout". The profile of an individual with a propensity to"burn out" is a single man, with a median age of 27, that is in the first years of the graduate program and that combines studies with 30 hours of clinical practice and/or other work (p<0,05). Narcissistic and borderline are the types of personality most frequently found in the individuals that present"burnout" syndrome (p<0,05). Conclusions: In general, no high levels of"burnout" were registered in the studied population, only 2-3%, if applying strict definition of"burnout", and 10% if these criteria were amplified. We believe it is necessary to identify the individuals with a tendency towards"burnout", in order to establish preventive measures and avoid future negative behaviour at work as well as at the personal level.

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The objective of this work was to evaluate the possibility of obtaining recombinant inbred wheat lines more resistant to preharvest sprouting, independently of colour genes, in three red-grained Brazilian wheat populations. The results showed statistical significance among lines within all populations, which presented a normal distribution and transgressive segregation for preharvest sprouting. The normal distribution of the lines from all red-grained populations suggests that sprouting, excluding the genes expressing seed coat pigmentation, is, probably, controlled by many genes. These findings also indicate that it may be possible to improve resistance to preharvest sprouting, independently of the colour genes.

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Further knowledge of the processes conditioning nitrogen use efficiency (NUE) is of great relevance to crop productivity. The aim of this paper was characterise C and N partitioning during grain filling and their implications for NUE. Cereals such as bread wheat (Triticum aestivum L. cv Califa sur), triticale (× Triticosecale Wittmack cv. Imperioso) and tritordeum (× Tritordeum Asch. & Graebn line HT 621) were grown under low (LN, 5 mm NH4NO3) and high (HN, 15 mm NH4NO3) N conditions. We conducted simultaneous double labelling (12CO2 and 15NH415NO3) in order to characterise C and N partitioning during grain filling. Although triticale plants showed the largest total and ear dry matter values in HN conditions, the large investment in shoot and root biomass negatively affected ear NUE. Tritordeum was the only genotype that increased NUE in both N treatments (NUEtotal), whereas in wheat, no significant effect was detected. N labelling revealed that N fertilisation during post-anthesis was more relevant for wheat and tritordeum grain filling than for triticale. The study also revealed that the investments of C and N in flag leaves and shoots, together with the"waste" of photoassimilates in respiration, conditioned the NUE of plants, and especially under LN. These results suggest that C and N use by these plants needs to be improved in order to increase ear C and N sinks, especially under LN. It is also remarkable that even though tritordeum shows the largest increase in NUE, the low yield of this cereal limits its agronomic value.

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The aim of this study was to culture human fetal bone cells (dedicated cell banks of fetal bone derived from 14 week gestation femurs) within both hyaluronic acid gel and collagen foam, to compare the biocompatibility of both matrices as potential delivery systems for bone engineering and particularly for oral application. Fetal bone cell banks were prepared from one organ donation and cells were cultured for up to 4 weeks within hyaluronic acid (Mesolis(®)) and collagen foams (TissueFleece(®)). Cell survival and differentiation were assessed by cell proliferation assays and histology of frozen sections stained with Giemsa, von Kossa and ALP at 1, 2 and 4 weeks of culture. Within both materials, fetal bone cells could proliferate in three-dimensional structure at ∼70% capacity compared to monolayer culture. In addition, these cells were positive for ALP and von Kossa staining, indicating cellular differentiation and matrix production. Collagen foam provides a better structure for fetal bone cell delivery if cavity filling is necessary and hydrogels would permit an injectable technique for difficult to treat areas. In all, there was high biocompatibility, cellular differentiation and matrix deposition seen in both matrices by fetal bone cells, allowing for easy cell delivery for bone stimulation in vivo. Copyright © 2011 John Wiley & Sons, Ltd.

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Astrocytes can experience large intracellular Na+ changes following the activation of the Na+-coupled glutamate transport. The present study investigated whether cytosolic Na+ changes are transmitted to mitochondria, which could therefore influence their function and contribute to the overall intracellular Na+ regulation. Mitochondrial Na+ (Na+(mit)) changes were monitored using the Na+-sensitive fluorescent probe CoroNa Red (CR) in intact primary cortical astrocytes, as opposed to the classical isolated mitochondria preparation. The mitochondrial localization and Na+ sensitivity of the dye were first verified and indicated that it can be safely used as a selective Na+(mit) indicator. We found by simultaneously monitoring cytosolic and mitochondrial Na+ using sodium-binding benzofuran isophthalate and CR, respectively, that glutamate-evoked cytosolic Na+ elevations are transmitted to mitochondria. The resting Na+(mit) concentration was estimated at 19.0 +/- 0.8 mM, reaching 30.1 +/- 1.2 mM during 200 microM glutamate application. Blockers of conductances potentially mediating Na+ entry (calcium uniporter, monovalent cation conductances, K+(ATP) channels) were not able to prevent the Na+(mit) response to glutamate. However, Ca2+ and its exchange with Na+ appear to play an important role in mediating mitochondrial Na+ entry as chelating intracellular Ca2+ with BAPTA or inhibiting Na+/Ca2+ exchanger with CGP-37157 diminished the Na+(mit) response. Moreover, intracellular Ca2+ increase achieved by photoactivation of caged Ca2+ also induced a Na+(mit) elevation. Inhibition of mitochondrial Na/H antiporter using ethylisopropyl-amiloride caused a steady increase in Na+(mit) without increasing cytosolic Na+, indicating that Na+ extrusion from mitochondria is mediated by these exchangers. Thus, mitochondria in intact astrocytes are equipped to efficiently sense cellular Na+ signals and to dynamically regulate their Na+ content.

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Long-term effects of trimethyltin (TMT) applied at concentrations below the cytotoxic level were examined in three-dimensional cell cultures of fetal rat telencephalon using biochemical, immunochemical and morphological criteria. It was found that in immature cultures low concentrations of TMT (10(-8) M) specifically induced a gliotic response in astrocytes, with increased immunoreactivity for glial fibrillary acidic protein, and a greater number of astrocytic processes. Significant changes in oligodendrocytic and neuronal parameters were found only at 10(-6) M of TMT. In differentiated cultures, distinct changes in cell type-specific parameters occurred at 10(-6) M of TMT (the lowest effective concentration). In addition, different patterns of responses were found for astrocytes and oligodendrocytes, as compared to immature cultures. These results suggest that among neural cells, astroblasts are most sensitive to TMT, and that the glial responses to this neurotoxicant are development-dependent.

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The objective of this work was to compare the meiotic behavior and pollen grain viability of three species of Crotalaria. Slides for meiotic analysis were prepared by the air-drying technique. Pollen grain viability was measured by three staining procedures (Alexander's solution, tetrazolium chloride and fluorescein diacetate) and in vitro germination in a sucrose solution. Eight bivalents were observed, confirming previous reports on populations from other regions of Brazil, as well as from other countries. All species showed abnormal meiotic behavior as follows: in Crotalaria micans, cytomixis and abnormal chromosome pairing in diakinesis; in C. spectabilis, abnormal chromosome pairing in diplotene; in C. zanzibarica, shrunk nuclei in leptotene and zygotene. Pollen grains of all three species show low viability, which may be associated with the irregularities of the meiotic behavior.

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This review covers some of the contributions to date from cerebellar imaging studies performed at ultra-high magnetic fields. A short overview of the general advantages and drawbacks of the use of such high field systems for imaging is given. One of the biggest advantages of imaging at high magnetic fields is the improved spatial resolution, achievable thanks to the increased available signal-to-noise ratio. This high spatial resolution better matches the dimensions of the cerebellar substructures, allowing a better definition of such structures in the images. The implications of the use of high field systems is discussed for several imaging sequences and image contrast mechanisms. This review covers studies which were performed in vivo in both rodents and humans, with a special focus on studies that were directed towards the observation of the different cerebellar layers.

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Values and value processes are said to be needed in every organization nowadays, as the world is changing and companies have to have something to "keep it together". Organizational values, which are approvedand used by the personnel, could be the key. Every organization has values. But what is the real value of values? The greatest and most crucial challenge is the feasibility of the value process. The main point in this thesis is tostudy how organizational members at different hierarchical levels perceive values and value processes in their organizations. This includes themes such as how values are disseminated, the targets of value processing, factors that affect the process, problems that occur during the value implementation and improvements that could be made when organizational values are implemented. These subjects are studied from the perspective of organizational members (both managers and employees); individuals in the organizations. The aim is to get the insider-perspective on value processing, from multiple hierarchical levels. In this research I study three different organizations (forest industry, bank and retail cooperative) and their value processes. The data is gathered from companies interviewing personnel in the head office and at the local level. The individuals areseen as members of organizations, and the cultural aspect is topical throughout the whole study. Values and cultures are seen as the 'actuality of reality' of organizations, interpreted by organizational members. The three case companies were chosen because they represented different lines of business and they all implemented value processing differently. Sincethe emphasis in this study is at the local level, the similar size of the local units was also an important factor. Values are in 'fashion' -but what does the fashion tell us about the real corporate practices? In annual reports companies emphasize the importance and power of official values. But what is the real 'point' of values? Values are publicly respected and advertised, but still it seems that the words do not meet the deeds. There is a clear conflict between theoretical, official and substantive organizational values: in the value processing from words to real action. This contradiction in value processing is studied through individual perceptions in this study. I study the kinds of perceptions organizationalmembers have when values are processed from the head office to the local level: the official value process is studied from the individual's perspective. Value management has been studied more during the 1990's. The emphasis has usually been on managers: how they consider the values in organizations and what effects it has on the management. Recent literature has emphasized values as tools for improving company performance. The value implementation as a process has been studied through 'good' and 'bad' examples, as if one successful value process could be copied to all organizations. Each company is different with different cultures and personnel, so no all-powerful way of processing values exists. In this study, the organizational members' perceptions at different hierarchical levels are emphasized. Still, managers are also interviewed; this is done since managerial roles in value dissemination are crucial. Organizational values cannot be well disseminated without management; this has been proved in several earlier studies (e.g. Kunda 1992, Martin 1992, Parker 2000). Recent literature has not sufficiently emphasized the individual's (organizational member's) role in value processing. Organizations consist of differentindividuals with personal values, at all hierarchical levels. The aim in this study is to let the individual take the floor. Very often the value process is described starting from the value definition and ending at dissemination, and the real results are left without attention. I wish to contribute to this area. Values are published officially in annual reports etc. as a 'goal' just like profits. Still, the results/implementationof value processing is rarely followed, at least in official reports. This is a very interesting point: why do companies espouse values, if there is no real control or feedback after the processing? In this study, the personnel in three different companies is asked to give an answer. In the empirical findings, there are several results which bring new aspects to the research area of organizational values. The targets of value processing, factors effecting value processing, the management's roles and the problems in value implementation are presented through the individual's perspective. The individual's perceptions in value processing are a recurring theme throughout the whole study. A comparison between the three companies with diverse value processes makes the research complete

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Theory states that genes on the sex chromosomes have stronger effects on sexual dimorphism than genes on the autosomes. Although empirical data are not necessarily consistent with this theory, this situation may prevail because the relative role of sex-linked and autosomally inherited genes on sexual dimorphism has rarely been evaluated. We estimated the quantitative genetics of three sexually dimorphic melanin-based traits in the barn owl (Tyto alba), in which females are on average darker reddish pheomelanic and display more and larger black eumelanic feather spots than males. The plumage traits with higher sex-linked inheritance showed lower heritability and genetic correlations, but contrary to prediction, these traits showed less pronounced sexual dimorphism. Strong offspring sexual dimorphism primarily resulted from daughters not expressing malelike melanin-based traits and from sons expressing femalelike traits to similar degrees as their sisters. We conclude that in the barn owl, polymorphism at autosomal genes rather than at sex-linked genes generate variation in sexual dimorphism in melanin-based traits.

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A weak version of the cosmic censorship hypothesis is implemented as a set of boundary conditions on exact semiclassical solutions of two-dimensional dilaton gravity. These boundary conditions reflect low-energy matter from the strong coupling region and they also serve to stabilize the vacuum of the theory against decay into negative energy states. Information about low-energy incoming matter can be recovered in the final state but at high energy black holes are formed and inevitably lead to information loss at the semiclassical level.

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A one-parameter class of simple models of two-dimensional dilaton gravity, which can be exactly solved including back-reaction effects, is investigated at both classical and quantum levels. This family contains the RST model as a special case, and it continuously interpolates between models having a flat (Rindler) geometry and a constant curvature metric with a nontrivial dilaton field. The processes of formation of black hole singularities from collapsing matter and Hawking evaporation are considered in detail. Various physical aspects of these geometries are discussed, including the cosmological interpretation.