Melatonin in Chinese medicinal herbs

Melatonin is a highly conserved molecule that not only exists in animals, but also is present in bacteria, unicellular organisms and in plants. Since melatonin is an antioxidant, in plants melatonin was speculated to protect them from intrinsic and environmental oxidative stress. More importantly, melatonin in edible plants inevitably enters animals and human through feed and food. In this study, more than 100 Chinese medicinal herbs were analyzed using the methods of solid phase extraction and HPLC-FD on-line with MS to determine whether melatonin is present in these commonly used herbs. Melatonin was detected in majority of these plants. Sixty-four of them contain melatonin in excess of 10 ng per gram dry mass. Melatonin levels in several herbs are in excess of 1000 ng/g. It is well known that normal average physiological plasma levels of melatonin are only 10-60 pg/mL. These high level-melatonin containing plants are traditionally used to treat diseases which presumably involve free radical damage. The current study provides new information concerning one potentially effective constituent present in a large number of medicinal herbs. The results suggest that these herbs should be reevaluated in reference to their nutritional and medicinal value. (C) 2003 Elsevier Science Inc. All rights reserved.

Hardness of covalent crystals

Based on the idea that the hardness of covalent crystal is intrinsic and equivalent to the sum of the resistance to the indenter of each bond per unit area, a semiempirical method for the evaluation of hardness of multicomponent crystals is presented. Applied to beta-BC2N crystal, the predicted value of hardness is in good agreement with the experimental value. It is found that bond density or electronic density, bond length, and degree of covalent bonding are three determinative factors for the hardness of a polar covalent crystal. Our method offers the advantage of applicability to a broad class of materials and initializes a link between macroscopic property and electronic structure from first principles calculation.

STATISTICAL THERMODYNAMICS OF POLYDISPERSE POLYMER MIXTURES

A statistical thermodynamics theory of polydisperse polymer blends based on a lattice model description of a fluid is formulated. Characterization of a binary polydisperse polymer mixture requires a knowledge of the pure polymer system and the interaction energy. It is assumed that the intrinsic and interactive properties of polymer (for example, T*, P*, rho*, and epsilon(ij)*) are independent of molecular size. Thermodynamic properties of ternary and higher order mixtures are completely defined in terms of the pure fluid polymer parameters and the binary interaction energies. Thermodynamic stability criteria for the phase transitions of a binary mixture are shown. The binodal and spinodal of general binary systems and of special binary systems are discussed.

TRACE observations of driven loop oscillations

Aims: On 13 June 1998, the TRACE satellite was fortuitously well placed to observe the effects of a flare-induced EIT wave in the corona, and its subsequent interaction with coronal magnetic loops. In this study, we use these TRACE observations to corroborate previous theoretical work, which determined the response of a coronal loop to a harmonic driver in the context of ideal magnetohydrodynamics, as well as estimate the magnetic field strength and the degree of longitudinal inhomogeneity. Methods: Loop edges are tracked, both spatially and temporally, using wavelet modulus maxima algorithms, with corresponding loop displacements from its quiescent state analysed by fitting scaled sinusoidal functions. The physical parameters of the coronal loop are subsequently determined using seismological techniques. Results: The studied coronal loop is found to oscillate with two distinct periods, 501 ± 5 s and 274 ± 7 s, which could be interpreted as belonging to the fundamental kink mode and first harmonic, or could reflect the stage of an overdriven loop. Additional scenarios for explaining the two periods are listed, each resulting in a different value of the magnetic field and the intrinsic and sub-resolution properties of the coronal loop. When assuming the periods belong to the fundamental kink mode and its first harmonic, we obtain a magnetic field strength inside the oscillating coronal loop of 2.0 ± 0.7 G. In contrast, interpreting the oscillations as a combination of the loop's natural kink frequency and a harmonic EIT wave provides a magnetic field strength of 5.8 ± 1.5 G. Using the ratio of the two periods, we find that the gravitational scale height in the loop is 73 ± 3 Mm. Conclusions: We show that the observation of two distinct periods in a coronal loop does not necessarily lead to a unique conclusion. Multiple plausible scenarios exist, suggesting that both the derived strength of the magnetic field and the sub-resolution properties of the coronal loop depend entirely on which interpretation is chosen. The interpretation of the observations in terms of a combination of the natural kink mode of the coronal loop, driven by a harmonic EIT wave seems to result in values of the magnetic field consistent with previous findings. Other interpretations, which are realistic, such as kink fundamental mode/first harmonic and the oscillations of two sub-resolution threads result in magnetic field strengths that are below the average values found before.

MiR-433 induces cellular senescence rendering ovarian cancer cells less likely to undergo chemotherapy-induced apoptosis

Annually, ovarian cancer (OC) affects 240,000 women worldwide and is the most lethal gynaecological malignancy. Such mortality is predominantly associated with the development of an intrinsic and acquired resistance to chemotherapy, the lack of targeted therapies and the lack of biomarkers predicting therapeutic response.

Our clinical data demonstrates that increased miR-433 expression in primary high grade serous OC (HGSOCs) is significantly associated with poor PFS (n=46, p=0.024). Interestingly, the IHC analysis of two miR-433 targets: MAD2 [Furlong et al., 2012 PMID:22069160] and HDAC6 shows that low IHC levels of both proteins is also significantly associated with worse outcome (p=0.002 and 0.002 respectively; n=43). Additionally, the analysis of miR 433 in the publicly available TCGA dataset corroborates that high miR-433 is significantly correlated with worse OS for patients presenting with OC (n=558 and p=0.027). In vitro, in a panel of OC cell lines, higher miR-433 and lower MAD2 and HDAC6 levels were associated with resistance to paclitaxel.

To further investigate the role of miR-433 in the cellular response to chemotherapy, we generated an OC cell line stably expressing miR-433, or miR-control. MTT viability assays and Western Blot analyses established that miR-433 cells were more resistant to paclitaxel treatment (50nM) compared to miR-controls. Importantly, we have shown for the first time that miR 433 induced senescence, exemplified by a flattened morphology and down-regulation of phosphorylated Retinoblastoma (p-Rb), a molecular marker of senescence. Surprisingly, miR 433 induced senescence was independent from two well recognised senescent drivers: namely p53/p21 and p16. To explore this further we performed an in silico analysis of seven microRNA platforms which indicated that miR 433 potentially targets Cyclin-dependent kinase CDK6, which promotes sustained phosphorylation of Rb and thus cell cycle progression. In vitro, the overexpression of pre-miR-433 resulted in diminished CDK6 expression demonstrating a novel interaction between miR-433 and CDK6.

In conclusion, this study demonstrates that high miR-433 expression predicts poor outcome in OC patients by putatively rendering OC cells resistant to paclitaxel treatment through the induction of cellular senescence identifying this microRNA as a potential marker of chemoresponse.

MIR-433 Predicts poor response to chemotherapy in ovarian cancer patients by the induction of cellular senescence

Annually, ovarian cancer (OC) affects 240,000 women worldwide and is the most lethal gynaecological malignancy. Such mortality is predominantly associated with the development of an intrinsic and acquired resistance to chemotherapy, the lack of targeted therapies and the lack of biomarkers predicting response to standard treatment.

Our clinical data demonstrates that increased miR-433 expression in primary high grade serous OC (HGSOCs) is significantly associated with poor PFS (n=46, p=0.024). Interestingly, the IHC analysis of two miR-433 targets: MAD2 [1] and HDAC6 shows that low IHC levels of both proteins is also significantly associated with worse outcome (p=0.002 and 0.002 respectively; n=43). Additionally, the analysis of miR 433 in the publicly available TCGA dataset corroborates that high miR-433 is significantly correlated with worse OS for patients presenting with OC (n=558 and p=0.027). In vito, in a panel of OC cell lines, higher miR-433 and lower MAD2 and HDAC6 levels were associated with resistance to paclitaxel.

To further investigate the role of miR-433 in the cellular response to chemotherapy, we generated an OC cell line stably expressing miR-433 or miR-control. MTT viability assays and Western Blot analyses established that miR-433 cells were more resistant to paclitaxel treatment (50nM) compared to miR-controls. Importantly, we have shown for the first time that miR 433 induced senescence resulting in a chracteristic flattened morphology and down-regulation of phosphorylated Retinoblastoma (p Rb), a molecular marker of senescence. Surprisingly, miR 433 induced senescence was independent from two well recognised senescent drivers: namely p53/p21 and p16. To explore this further we performed an in silico analysis of seven microRNA platforms which indicated that miR 433 potentially targets Cyclin-dependent kinase CDK6, which promotes sustained phosphorylation of Rb and thus cell cycle progression. In vitro, the overexpression of pre-miR-433 resulted in diminished CDK6 expression demonstrating a novel interaction between miR-433 and CDK6.

In conclusion, this study demonstrates that high miR-433 expression predicts poor outcome in OC patients by putatively rendering OC cells resistant to paclitaxel treatment through the induction of cellular senescence identifying this microRNA as a potential marker of chemoresponse.

A audácia de ser diferente: a escrita obsessiva de Ana Teresa Pereira

A presente tese tem como objetivo estudar a obra da escritora madeirense Ana Teresa Pereira. Partindo da leitura integral dos seus livros, que se interligam formando um todo caraterizado por uma unidade intrínseca e obsessiva, e analisando especificamente a obra publicada entre 1989 e 2008, procurámos demonstrar os tópicos que permitem classificar a sua poética como uma escrita obsessiva e audaz, sob o ponto de vista do que de mais espantoso as expressões podem ter. Estamos perante uma obra cuja indivisibilidade labiríntica se entretece com a paixão obsessiva pela Arte, em particular, pela Literatura, pelo Cinema, pela Pintura e pela Música.

Potencial das atividades desenvolvidas por docentes de música para a perda auditiva induzida por ruído

A perda auditiva por exposição ao ruído é um problema de saúde ocupacional, não reconhecido nas escolas de música. Em Portugal, a legislação relativa a ruído ocupacional não possui indicações específicas para músicos, existindo apenas um código de conduta europeu, proveniente da Diretiva 2003/10/CE que estabelece as orientações gerais relativas a como devem ser protegidos do ruído músicos e trabalhadores de setores de entretenimento. Avaliou-se o nível sonoro contínuo equivalente (LAeq), individualmente no decorrer das atividades letivas, o que permitiu determinar o nível exposição pessoal diária ao ruído (Lex,8h) de 20 docentes de música. Paralelamente, os docentes preencheram um questionário relativo a fatores intrínsecos e individuais e todos efetuaram audiogramas tonais simples. Os dados recolhidos foram estatisticamente tratados através do programa Statistical Package for Social Sciences (SPSS) versão 21. Existem atividades letivas que implicam níveis de exposição pessoal diária ao ruído superiores ao nível de ação inferior (25%), pelo que se devem adotar medidas para sensibilizar e alertar os docentes para a adoção de medidas de proteção. A atividade dos docentes expostos a níveis de exposição pessoal diária mais elevados correspondeu a aulas de grupo e a aulas individuais, com utilização de instrumentos musicais direcionais. A manifestação de sintomatologia relevante relativa a perda auditiva (audição de zumbidos, dificuldades de perceção do diálogo e dificuldade em adormecer) e a evolução da surdez profissional, não parecem estar diretamente relacionadas com os níveis de exposição pessoal diária ao ruído nem atividades com exposição ao ruído desenvolvidas nos tempos livres.

Are there transformative indicators for motivation to learn?

Fourteen nursing s tudents enrolled in a community coll ege were chosen by purposeful se lection to be i nterviewed in a qualitative survey. A proposed mode l of Learner Motivation Development was examined . The mode l describes four stages of motivati on development progression across the lifespan: I Survival (infancy to childhood), I I Expl oration (childhood to adolescence), III Identification (pre- adulthood), and IV Reflection ( adulthood ). This r esearch examined the last two stages. The criteria used to categorize the students within the fr amework were bas ed on human development theories as described by Maslow (1954) and Erikson (1950). The concept of critica l thinking proposed by Brookfield (1987) and the ideas of transformative learning expressed by Mezirow (1991) were also incorporated. The researcher' s criteria , antici pated behaviours and characteri stics, were used to ana lyze the students' responses to open-ended questions. The central theme of the research was based on the assumption that motivation to learn is intrinsic and inherent in pre-adult and adult learners. Six pre-adults and two adults met the descriptors set for stage III Identification. Five adults and one pre-adult met the criteria for stage IV Reflection. The impact of life e xperiences and maturation were clearly demonstrated.

Caractérisation de la dynamique des berges de deux tributaires contrastés du Saint-Laurent : le cas des rivières Batiscan et Saint-François

L’érosion des berges est un processus clé de la dynamique fluviale. Elle influence considérablement la charge sédimentaire des rivières et contrôle l’évolution latérale des chenaux. Les méthodes de caractérisation des mécanismes et des variables affectant l’érosion des berges sont toutefois imprécises et difficiles à appliquer. Ce projet a pour objectif de caractériser la dynamique actuelle des berges de deux tributaires contrastés du Saint-Laurent : les rivières Saint-François et Batiscan. Le premier objectif vise à quantifier les caractéristiques géotechniques de deux tronçons des rivières à l’étude près de l’embouchure avec le Saint-Laurent en décrivant la stratigraphie à différents sites typiques et en recueillant des échantillons de sédiments afin de mesurer différentes variables géotechniques (granulométrie, limites d’Atterberg, résistance à l’érosion mécanique, résistance à l’érosion fluviale). Le second objectif vise à quantifier les principales caractéristiques hydrodynamiques (précipitations, débits, cisaillements, vitesses) des deux sections de rivière. Le troisième et dernier objectif cherche à mesurer les taux d’érosion à l’échelle saisonnière en utilisant des relevés GPS et des chaînes d’érosion et à identifier les mécanismes d’érosion qui opèrent sur les rivières. Les résultats montrent une érosion importante des berges sur chacun des tributaires, mais les mécanismes qui la cause diffèrent. La Batiscan possède des berges dont le matériel est cohésif et ses berges sont principalement marquées par des ruptures de masse. La Saint-François présente des berges peu cohésives ce qui favorise l’érosion fluviale. Le taux de recul sur la rivière Saint-François est de l’ordre de 1 à 3 m/an dans certaines sections de la rivière. Une nouvelle méthode de mesure du cisaillement critique d’érosion fluviale à l’aide d’un chenal expérimental a été élaborée. Les cisaillements critiques obtenus se situent entre 1,19 et 13,41 Pa. Les résultats montrent que les facteurs jouant sur l’érosion des berges ont une variabilité intrinsèque et systémique difficile à mesurer. Le protocole expérimental développé dans ce projet s’est toutefois avéré utile pour étudier les principales variables qui influencent l’érosion des berges, tout en quantifiant les taux d’érosion et les mécanismes d’érosion de berge de deux tributaires importants du fleuve Saint-Laurent. Ce protocole pourrait être utile dans d’autres contextes.

Ordered mesoporous silica as supports for immobilization of biocatalyst

Mesoporous materials are of great interest to the materials community because of their potential applications for catalysis,separation of large molecules,medical implants,semiconductors,magnetoelectric devices.The thesis entitled 'Ordered Mesoporous Silica as supports for immobilization of Biocatalyst' presents how the pore size can be tuned without the loss in ordered structure for the entrapment of an industially important biocatalyst-amylase.Immobilization of enzymes on ordered mesoporous material has triggered new ooportunities for stabilizing enzymes with improved intrinsic and operational stabilities.

De Generalista a Especialista : Motivações para a formação especializada em enfermagem : o caso das organizações de saúde públicas, na sub-região oeste do distrito de Lisboa

O presente estudo, enquadrado na área de gestão de recursos humanos, tem como principal objectivo identificar os factores motivacionais que orientam a adesão à especialização, no grupo profissional dos enfermeiros. Trata-se de um estudo de natureza exploratória, transversal, descritivo, analítico, comparativo e quantitativo. A população do estudo foi o grupo de enfermeiros portugueses, sendo a sua amostra composta por 150 enfermeiros. Este grupo foi seleccionado a partir de um processo de amostragem probabilística estratificada, sem reposição. O instrumento de recolha de dados foi o inquérito por questionário. Para o efeito usou-se o questionário da motivação para a formação (QMF) de Carré (2001), tendo sido já adaptado para a população portuguesa por Correia (2009). A formação contínua é uma condição importante no desenvolvimento do indivíduo, quer a nível pessoal, quer a nível profissional; assim como no desempenho da organização onde o indivíduo exerce a sua profissão. O presente trabalho pretende, assim, identificar os factores motivacionais na função de enfermeiro, e que conduzem à adesão da especialização, em particular ao Curso de Pós-Licenciatura em Enfermagem. Numa primeira parte, faz-se a definição e avaliação da função, desenhando-se um mapa de competências; identificando-se, em paralelo, os motivos/expectativas que levam estes profissionais da saúde à especialização desta mesma escala. Decorrente dos resultados obtidos, o presente trabalho conclui que as duas principais motivações dos enfermeiros para a frequência do CPLEE são a motivação extrínseca Operacional Pessoal e a motivação extrínseca Operacional Profissional. Foi ainda possível determinar que a idade, o género, o vínculo à instituição e a situação financeira também têm um papel decisivo no que concerne à motivação dos enfermeiros para a frequência do CPLEE. Este estudo permitiu ainda consolidar o questionário da motivação para a formação desenvolvido por Philippe Carré, aplicado à população portuguesa, de forma a analisar a motivação dos enfermeiros portugueses para a frequência do CPLEE. Quanto às implicações práticas, pretende-se contribuir para o desenvolvimento e melhoria das práticas de recursos humanos no sector da saúde. Balança-se aqui, consequentemente, um equilíbrio entre o diagnóstico organizacional, e a prescrição prática. Potencialmente, poderá servir de roadmap para áreas como o recrutamento e selecção, gestão de carreiras, formação e desenvolvimento, desenho de trabalho e de funções; e, adicionalmente, para uma melhor gestão académica do ensino pós-graduado, na carreira da enfermagem.

Risky attitudes towards road use in pre-drivers

Motor vehicle accidents are one of the principal causes of adolescent disability or mortality and male drivers are more likely to be involved in road accidents than female drivers. In part such associations between driver age and sex have been linked to differences in risky behaviour (e.g. speed, violations) and individual characteristics (e.g. sensation seeking, deviant behaviour). The aim of this research is to determine whether associations between risky road user behaviour and individual characteristics are a function of driver behaviour or whether they are intrinsic and measurable in individuals too young to drive. Five hundred and sixty-seven pre-driver students aged 11-16 from three secondary schools completed questionnaires measuring enthusiasm for speed, sensation seeking, deviant behaviour and attitudes towards driver violations. Boys reported more risky attitudes than girls for all measures. Associations between sensation seeking, deviant behaviour and attitudes towards risky road use were present from early adolescence and were strongest around age 14, before individuals learn to drive. Risky attitudes towards road use are associated with individual characteristics and are observed in adolescents long before they learn to drive. Safe attitudes towards road use and driver behaviour should be promoted from childhood in order to be effective. (C) 2007 Elsevier Ltd. All rights reserved.

Motivation in second language acquisition in Chinese research students in the UK

The present study sets out to examine motivation to learn English by Chinese research students in an informal setting. Data were collected, using semi-structured interviews, from four research students at two points in time during their first year in the UK. The main findings are: they believed that learning English was important; their main goal orientations were instrumental and extrinsic; they set learning goals and persisted to attain them; they valued their current learning environment in general and saw it as supportive of their goals; they held both positive and negative attitudes towards the British, which had differential effects on their motivation; their self-perceived support seemed to have a positive impact on their motivation and the development of self-confidence; they tended to attribute their success to stable causes such as the environment and failure to unstable but controllable causes such as effort. It is concluded that qualitative data of this kind may complement insights from quantitative research. Implications for target country institutions in the provision of support are discussed.

Influência na qualidade final de metais retificados através da variação da velocidade de mergulho

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)