881 research outputs found

    Choosing the lesser of two evils, the better of two goods: Specifying the roles of ventromedial prefrontal cortex and dorsal anterior cingulate in object choice

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    The ventromedial prefrontal cortex (vmPFC) and dorsal anterior cingulate cortices (ACd) are considered important for reward-based decision making. However, work distinguishing their individual functional contributions has only begun. One aspect of decision making that has received little attention is that making the right choice often translates to making the better choice. Thus, response choice often occurs in situations where both options are desirable (e.g., choosing between mousse au chocolat or crème caramel cheesecake from a menu) or, alternatively, in situations where both options are undesirable. Moreover, response choice is easier when the reinforcements associated with the objects are far apart, rather than close together, in value. We used functional magnetic resonance imaging to delineate the functional roles of the vmPFC and ACd by investigating these two aspects of decision making: (1) decision form (i.e., choosing between two objects to gain the greater reward or the lesser punishment), and (2) between-object reinforcement distance (i.e., the difference in reinforcements associated with the two objects). Blood oxygen level-dependent (BOLD) responses within the ACd and vmPFC were both related to decision form but differentially. Whereas ACd showed greater responses when deciding between objects to gain the lesser punishment, vmPFC showed greater responses when deciding between objects to gain the greater reward. Moreover, vmPFC was sensitive to reinforcement expectations associated with both the chosen and the forgone choice. In contrast, BOLD responses within ACd, but not vmPFC, related to between-object reinforcement distance, increasing as the distance between the reinforcements of the two objects decreased. These data are interpreted with reference to models of ACd and vmPFC functioning

    The influence of sentinel lymph node tumour burden on additional lymph node involvement and disease-free survival in cutaneous melanoma – a retrospective analysis of 392 cases

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    Twenty per cent of sentinel lymph node (SLN)-positive melanoma patients have positive non-SLN lymph nodes in completion lymph node dissection (CLND). We investigated SLN tumour load, non-sentinel positivity and disease-free survival (DFS) to assess whether certain patients could be spared CLND. Sentinel lymph node biopsy was performed on 392 patients between 1999 and 2005. Median observation period was 38.8 months. Sentinel lymph node tumour load did not predict non-SLN positivity: 30.8% of patients with SLN macrometastases (⩾2 mm) and 16.4% with micrometastases (⩽2 mm) had non-SLN positivity (P=0.09). Tumour recurrences after positive SLNs were more than twice as frequent for SLN macrometastases (51.3%) than for micrometastases (24.6%) (P=0.005). For patients with SLN micrometastases, the DFS analysis was worse (P=0.003) when comparing those with positive non-SLNs (60% recurrences) to those without (17.6% recurrences). This difference did not translate into significant differences in DFS: patients with SLN micrometastasis, either with (P=0.022) or without additional positive non-SLNs (P<0.0001), fared worse than patients with tumour-free SLNs. The 2-mm cutoff for SLN tumour load accurately predicts differences in DFS. Non-SLN positivity in CLND, however, cannot be predicted. Therefore, contrary to other studies, no recommendations concerning discontinuation of CLND based on SLN tumour load can be deduced

    Considering the role of cognitive control in expert performance

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    © 2014, Springer Science+Business Media Dordrecht. Dreyfus and Dreyfus’ (1986) influential phenomenological analysis of skill acquisition proposes that expert performance is guided by non-cognitive responses which are fast, effortless and apparently intuitive in nature. Although this model has been criticised (e.g., by Breivik Journal of Philosophy of Sport, 34, 116–134 2007, Journal of the Philosophy of Sport, 40, 85–106 2013; Eriksen 2010; Montero Inquiry:An interdisciplinary Journal of Philosophy, 53, 105–122 2010; Montero and Evans 2011) for over-emphasising the role that intuition plays in facilitating skilled performance, it does recognise that on occasions (e.g., when performance goes awry for some reason) a form of ‘detached deliberative rationality’ may be used by experts to improve their performance. However, Dreyfus and Dreyfus (1986) see no role for calculative problem solving or deliberation (i.e., drawing on rules or mental representations) when performance is going well. In the current paper, we draw on empirical evidence, insights from athletes, and phenomenological description to argue that ‘continuous improvement’ (i.e., the phenomenon whereby certain skilled performers appear to be capable of increasing their proficiency even though they are already experts; Toner and Moran 2014) among experts is mediated by cognitive (or executive) control in three distinct sporting situations (i.e., in training, during pre-performance routines, and while engaged in on-line skill execution). We conclude by arguing that Sutton et al. Journal of the British Society for Phenomenology, 42, 78–103 (2011) ‘applying intelligence to the reflexes’ (AIR) approach may help to elucidate the process by which expert performers achieve continuous improvement through analytical/mindful behaviour during training and competition

    γ-Tocotrienol suppresses prostate cancer cell proliferation and invasion through multiple-signalling pathways

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    Tocotrienol-rich fraction (TRF) has demonstrated antiproliferative effect on prostate cancer (PCa) cells. To elucidate this anticancer property in PCa cells, this study aimed, first, to identify the most potent isomer for eliminating PCa cells; and second, to decipher the molecular pathway responsible for its activity. Results showed that the inhibitory effect of γ-tocotrienol was most potent, which resulted in induction of apoptosis as evidenced by activation of pro-caspases and the presence of sub-G1 cell population. Examination of the pro-survival genes revealed that the γ-tocotrienol-induced cell death was associated with suppression of NF-κB, EGF-R and Id family proteins (Id1 and Id3). Meanwhile, γ-tocotrienol treatment also resulted in the induction of JNK-signalling pathway and inhibition of JNK activity by a specific inhibitor (SP600125) was able to partially block the effect of γ-tocotrienol. Interestingly, γ-tocotrienol treatment led to suppression of mesenchymal markers and the restoration of E-cadherin and γ-catenin expression, which was associated with suppression of cell invasion capability. Furthermore, a synergistic effect was observed when cells were co-treated with γ-tocotrienol and Docetaxel. Our results suggested that the antiproliferative effect of γ-tocotrienol act through multiple-signalling pathways, and demonstrated for the first time the anti-invasion and chemosensitisation effect of γ-tocotrienol against PCa cells

    Period Increase and Amplitude Distribution of Kink Oscillation of Coronal Loop

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    Coronal loops exist ubiquitously in the solar atmosphere. These loops puzzle astronomers over half a century. Solar magneto-seismology (SMS) provides a unique way to constrain the physical parameters of coronal loops. Here, we study the evolution of oscillations of a coronal loop observed by the Atmospheric Imaging Assembly (AIA). We measure geometric and physical parameters of the loop oscillations. In particular, we find that the mean period of the oscillations increased from 1048 to 1264 s during three oscillatory cycles. We employ the differential emission measure method and apply the tools of SMS. The evolution of densities inside and outside the loop is analyzed. We found that an increase of density inside the loop and decrease of the magnetic field strength along the loop are the main reasons for the increase in the period during the oscillations. Besides, we also found that the amplitude profile of the loop is different from a profile would it be a homogeneous loop. It is proposed that the distribution of magnetic strength along the loop rather than density stratification is responsible for this deviation. The variation in period and distribution of amplitude provide, in terms of SMS, a new and unprecedented insight into coronal loop diagnostics

    Age and Diet Affect Gene Expression Profiles in Canine Liver Tissue

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    BACKGROUND: The liver plays a central role in nutrient and xenobiotic metabolism, but its functionality declines with age. Senior dogs suffer from many of the chronic hepatic diseases as elderly humans, with age-related alterations in liver function influenced by diet. However, a large-scale molecular analysis of the liver tissue as affected by age and diet has not been reported in dogs. METHODOLOGY/PRINCIPAL FINDINGS: Liver tissue samples were collected from six senior (12-year old) and six young adult (1-year old) female beagles fed an animal protein-based diet (APB) or a plant protein-based diet (PPB) for 12 months. Total RNA in the liver tissue was extracted and hybridized to Affymetrix GeneChip® Canine Genome Arrays. Using a 2.0-fold cutoff and false discovery rate <0.10, our results indicated that expression of 234 genes was altered by age, while 137 genes were differentially expressed by diet. Based on functional classification, genes affected by age and/or diet were involved in cellular development, nutrient metabolism, and signal transduction. In general, gene expression suggested that senior dogs had an increased risk of the progression of liver disease and dysfunction, as observed in aged humans and rodents. In particular for aged liver, genes related to inflammation, oxidative stress, and glycolysis were up-regulated, whereas genes related to regeneration, xenobiotic metabolism, and cholesterol trafficking were down-regulated. Diet-associated changes in gene expression were more common in young adult dogs (33 genes) as compared to senior dogs (3 genes). CONCLUSION: Our results provide molecular insight pertaining to the aged canine liver and its predisposition to disease and abnormalities. Therefore, our data may aid in future research pertaining to age-associated alterations in hepatic function or identification of potential targets for nutritional management as a means to decrease incidence of age-dependent liver dysfunction

    Eficácia do exercício físico na fadiga dos pacientes com câncer durante o tratamento ativo: revisão sistemática e meta-análise

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    El objetivo del estudio fue determinar la efectividad del ejercicio físico en la fatiga de pacientes con cáncer durante el tratamiento activo. Las bases de datos de PubMed Central, EMBASE y OVID fueron consultadas hasta abril de 2014 para identificar ensayos clínicos aleatorizados, que evaluaran el efecto del ejercicio en la fatiga de pacientes con cáncer sometidos a tratamiento activo. Once estudios (n = 1.407) fueron incluidos. La quimioterapia fue el tratamiento más común (n = 1.028). Los estudios tuvieron bajo riesgo de sesgo y alta calidad metodológica. Las estimaciones de efecto mostraron que el ejercicio físico mejoró significativamente la fatiga (SMD = -3,0; IC95%: -5,21; -0,80), p < 0,0001. Se encontraron efectos similares para el entrenamiento de resistencia (SMD = -4,5; IC95%: -7,24; -1,82), p = 0,001. Se encontraron mejoras significativas en pacientes con cáncer de mama y de próstata (p < 0,05). El ejercicio es una intervención segura y eficaz en el control de la fatiga en pacientes sometidos a tratamiento activoThis study aimed to determine the effectiveness of physical exercise in decreasing fatigue in cancer patients during active treatment. The PubMed Central, EMBASE, and OVID databases were consulted up to April 2014 to identify randomized clinical trials that evaluated the effect of exercise on fatigue in cancer patients undergoing active treatment. Eleven studies (n = 1,407) were included. Chemotherapy was the most common form of treatment (n = 1,028). The studies showed a low risk of bias and high methodological quality. Effect estimates showed that physical exercise significantly improved fatigue (SMD = -3.0; 95%CI: -5.21; -0.80), p < 0.0001. Similar effects were found for resistance training (SMD = -4.5; 95%CI: -7.24; -1.82), p = 0.001. Significant improvements were found in breast and prostate cancer patients (p < 0.05). Exercise is a safe and effective intervention in the management fatigue in cancer patients undergoing active treatmentO objetivo foi determinar a efetividade do exercício físico sobre a fadiga em pacientes com câncer durante o tratamento ativo. As bases de dados PubMed Central, EMBASE e OVID foram consultadas até abril de 2014 para identificar ensaios clínicos randomizados que avaliaram o efeito do exercício sobre a fadiga em pacientes com câncer em tratamento ativo. Onze estudos (n = 1.407) foram incluídos. A quimioterapia foi o tratamento mais comum (n = 1.028). Os estudos tiveram baixo risco de viés e alta qualidade metodológica. As estimativas de efeito mostraram que o exercício melhorou significativamente a fadiga (DMP = -3,0; IC95%: -5,21; -0,80), p < 0,0001. Efeitos semelhantes sobre o treinamento de resistência (DMP = -4,5; IC95%: -7,24; -1,82), p = 0,001 foram encontrados. O exercício físico é uma intervenção segura e eficaz contra a fadiga em pacientes submetidos ao tratamento ativoEl presente trabajo forma parte del Proyecto Práctica del autoexamen de seno y los conocimientos, factores de riesgo y estilos de vida relacionados con el cáncer de mama en mujeres jóvenes de la Universidad Santo Tomás de Bogotá: un análisis transversal (9ª Convocatoria FODEIN- Código del proyecto 4110060001 - 008)
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