Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 529
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Neuroimage ; 285: 120477, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38072338

RESUMO

For over a decade, electrophysiological studies have reported correlations between attention / perception and the phase of spontaneous brain oscillations. To date, these findings have been interpreted as evidence that the brain uses neural oscillations to sample and predict upcoming stimuli. Yet, evidence from simulations have shown that analysis artefacts could also lead to spurious pre-stimulus oscillations that appear to predict future brain responses. To address this discrepancy, we conducted an experiment in which visual stimuli were presented in time to specific phases of spontaneous alpha and theta oscillations. This allowed us to causally probe the role of ongoing neural activity in visual processing independent of the stimulus-evoked dynamics. Our findings did not support a causal link between spontaneous alpha / theta rhythms and behaviour. However, spurious correlations between theta phase and behaviour emerged offline using gold-standard time-frequency analyses. These findings are a reminder that care should be taken when inferring causal relationships between neural activity and behaviour using acausal analysis methods.


Assuntos
Atenção , Eletroencefalografia , Humanos , Eletroencefalografia/métodos , Estimulação Luminosa/métodos , Atenção/fisiologia , Percepção Visual/fisiologia , Encéfalo/fisiologia , Ritmo Teta/fisiologia
2.
Phys Rev Lett ; 130(20): 202501, 2023 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-37267578

RESUMO

We demonstrate a new technique for obtaining fission data for nuclei away from ß stability. These types of data are pertinent to the astrophysical r process, crucial to a complete understanding of the origin of the heavy elements, and for developing a predictive model of fission. These data are also important considerations for terrestrial applications related to power generation and safeguarding. Experimentally, such data are scarce due to the difficulties in producing the actinide targets of interest. The solenoidal-spectrometer technique, commonly used to study nucleon-transfer reactions in inverse kinematics, has been applied to the case of transfer-induced fission as a means to deduce the fission-barrier height, among other variables. The fission-barrier height of ^{239}U has been determined via the ^{238}U(d,pf) reaction in inverse kinematics, the results of which are consistent with existing neutron-induced fission data indicating the validity of the technique.

3.
Neuropsychol Rehabil ; 33(4): 574-591, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-35168480

RESUMO

The ability to monitor one's behaviour is frequently impaired following TBI, impacting on patients' rehabilitation. Inaccuracies in judgement or self-reflection of one's performance provides a useful marker of metacognition. However, metacognition is rarely measured during routine neuropsychology assessments and how it varies across cognitive domains is unclear. A cohort of participants consisting of 111 TBI patients [mean age = 45.32(14.15), female = 29] and 84 controls [mean age = 31.51(12.27), female = 43] was studied. Participants completed cognitive assessments via a bespoke digital platform on their smartphones. Included in the assessment were a prospective evaluation of memory and attention, and retrospective confidence judgements of task performance. Metacognitive accuracy was calculated from the difference between confidence judgement of task performance and actual performance. Prospective judgment of attention and memory was correlated with task performance in these domains for controls but not patients. TBI patients had lower task performance in processing speed, executive functioning and working memory compared to controls, maintaining high confidence, resulting in overestimation of cognitive performance compared to controls. Additional judgments of task performance complement neuropsychological assessments with little additional time-cost. These results have important theoretical and practical implications for evaluation of metacognitive impairment in TBI patients and neurorehabilitation.


Assuntos
Lesões Encefálicas Traumáticas , Metacognição , Humanos , Feminino , Pessoa de Meia-Idade , Adulto , Estudos Retrospectivos , Função Executiva , Julgamento , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/psicologia
4.
Phys Rev Lett ; 129(15): 152501, 2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36269970

RESUMO

Absolute cross sections for the addition of s- and d-wave neutrons to ^{14}C and ^{14}N have been determined simultaneously via the (d,p) reaction at 10 MeV/u. The difference between the neutron and proton separation energies, ΔS, is around -20 MeV for the ^{14}C+n system and +8 MeV for ^{14}N+n. The population of the 1s_{1/2} and 0d_{5/2} orbitals for both systems is reduced by a factor of approximately 0.5 compared with the independent single-particle model, or about 0.6 when compared with the shell model. This finding strongly contrasts with results deduced from intermediate-energy knockout reactions between similar nuclei on targets of ^{9}Be and ^{12}C. The simultaneous technique used removes many systematic uncertainties.

5.
Phys Rev Lett ; 124(6): 062502, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32109128

RESUMO

The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical r process in producing nuclei heavier than A∼190. Despite their importance, the structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in ^{207}Hg have been probed using the neutron-adding (d,p) reaction in inverse kinematics. The radioactive beam of ^{206}Hg was delivered to the new ISOLDE Solenoidal Spectrometer at an energy above the Coulomb barrier. The spectroscopy of ^{207}Hg marks a first step in improving our understanding of the relevant structural properties of nuclei involved in a key part of the path of the r process.

6.
BMC Public Health ; 20(1): 1902, 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-33302899

RESUMO

BACKGROUND: This paper aims to explore change in BMI z-score through childhood and the association between parent BMI and child BMI z-score. This is important to understand for the development of effective obesity interventions. METHODS: Data from the longitudinal B-ProAct1v study (1837 participants) were analysed. A paired sample t-test examined changes in child BMI z-score between Year 1 and 4. Multivariable linear regression models examined the cross-sectional associations between child BMI z-score and parent BMI in Year 1 and 4. The influence of change in parental BMI between Year 1 and Year 4 on child BMI z-score in Year 4 was explored through regression analyses, adjusted for baseline BMI z-score. RESULTS: There was a strong association between child BMI z-score at Year 1 and 4. Child mean BMI z-score score increased from 0.198 to 0.330 (p = < 0.005) between these timepoints. For every unit increase in parent BMI, there was an increase in child BMI z-score of 0.047 in Year 1 (p = < 0.005) and of 0.059 in Year 4 (p = < 0.005). Parental BMI change was not significantly associated with Year 4 child BMI z-score. CONCLUSION: The key indicator of higher child BMI at Year 4 is high BMI at Year 1. Further studies are needed to explore the impact of parental weight change on child BMI z-score and whether interventions targeted at overweight or obese parents, can improve their child's BMI z-score.


Assuntos
Sobrepeso , Pais , Índice de Massa Corporal , Criança , Estudos Transversais , Humanos , Estudos Longitudinais , Instituições Acadêmicas
7.
J Intern Med ; 285(6): 624-634, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30481401

RESUMO

Traumatic brain injury (TBI) is clinically divided into a spectrum of severities, with mild TBI being the least severe form and a frequent occurrence in contact sports, such as ice hockey, American football, rugby, horse riding and boxing. Mild TBI is caused by blunt nonpenetrating head trauma that causes movement of the brain and stretching and tearing of axons, with diffuse axonal injury being a central pathogenic mechanism. Mild TBI is in principle synonymous with concussion; both have similar criteria in which the most important elements are acute alteration or loss of consciousness and/or post-traumatic amnesia following head trauma and no apparent brain changes on standard neuroimaging. Symptoms in mild TBI are highly variable and there are no validated imaging or fluid biomarkers to determine whether or not a patient with a normal computerized tomography scan of the brain has neuronal damage. Mild TBI typically resolves within a few weeks but 10-15% of concussion patients develop postconcussive syndrome. Repetitive mild TBI, which is frequent in contact sports, is a risk factor for a complicated recovery process. This overview paper discusses the relationships between repetitive head impacts in contact sports, mild TBI and chronic neurological symptoms. What are these conditions, how common are they, how are they linked and can they be objectified using imaging or fluid-based biomarkers? It gives an update on the current state of research on these questions with a specific focus on clinical characteristics, epidemiology and biomarkers.


Assuntos
Traumatismos em Atletas/diagnóstico , Traumatismos em Atletas/epidemiologia , Concussão Encefálica/diagnóstico , Concussão Encefálica/epidemiologia , Adolescente , Adulto , Traumatismos em Atletas/reabilitação , Biomarcadores/análise , Concussão Encefálica/reabilitação , Criança , Humanos , Escala de Gravidade do Ferimento
8.
Mol Psychiatry ; 23(5): 1385-1392, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28439103

RESUMO

Age-associated disease and disability are placing a growing burden on society. However, ageing does not affect people uniformly. Hence, markers of the underlying biological ageing process are needed to help identify people at increased risk of age-associated physical and cognitive impairments and ultimately, death. Here, we present such a biomarker, 'brain-predicted age', derived using structural neuroimaging. Brain-predicted age was calculated using machine-learning analysis, trained on neuroimaging data from a large healthy reference sample (N=2001), then tested in the Lothian Birth Cohort 1936 (N=669), to determine relationships with age-associated functional measures and mortality. Having a brain-predicted age indicative of an older-appearing brain was associated with: weaker grip strength, poorer lung function, slower walking speed, lower fluid intelligence, higher allostatic load and increased mortality risk. Furthermore, while combining brain-predicted age with grey matter and cerebrospinal fluid volumes (themselves strong predictors) not did improve mortality risk prediction, the combination of brain-predicted age and DNA-methylation-predicted age did. This indicates that neuroimaging and epigenetics measures of ageing can provide complementary data regarding health outcomes. Our study introduces a clinically-relevant neuroimaging ageing biomarker and demonstrates that combining distinct measurements of biological ageing further helps to determine risk of age-related deterioration and death.


Assuntos
Envelhecimento/fisiologia , Encéfalo/fisiologia , Neuroimagem/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/metabolismo , Biomarcadores , Encéfalo/metabolismo , Cognição/fisiologia , Epigênese Genética/genética , Epigenômica/métodos , Feminino , Humanos , Estudos Longitudinais , Aprendizado de Máquina , Masculino , Pessoa de Meia-Idade
9.
Neuroradiology ; 59(9): 893-903, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28744730

RESUMO

PURPOSE: Diffusion tensor imaging (DTI) has shown promise in the measurement of peripheral nerve integrity, although the optimal way to apply the technique for the study of lumbar spinal nerves is unclear. The aims of this study are to use an improved DTI acquisition to investigate lumbar nerve root integrity and correlate this with functional measures using neurophysiology. METHODS: Twenty healthy volunteers underwent 3 T DTI of the L5/S1 area. Regions of interest were applied to L5 and S1 nerve roots, and DTI metrics (fractional anisotropy, mean, axial and radial diffusivity) were derived. Neurophysiological measures were obtained from muscles innervated by L5/S1 nerves; these included the slope of motor-evoked potential input-output curves, F-wave latency, maximal motor response, and central and peripheral motor conduction times. RESULTS: DTI metrics were similar between the left and right sides and between vertebral levels. Conversely, significant differences in DTI measures were seen along the course of the nerves. Regression analyses revealed that DTI metrics of the L5 nerve correlated with neurophysiological measures from the muscle innervated by it. CONCLUSION: The current findings suggest that DTI has the potential to be used for assessing lumbar spinal nerve integrity and that parameters derived from DTI provide quantitative information which reflects their function.


Assuntos
Imagem de Tensor de Difusão/métodos , Região Lombossacral , Raízes Nervosas Espinhais/diagnóstico por imagem , Raízes Nervosas Espinhais/fisiologia , Adulto , Anisotropia , Eletromiografia , Potencial Evocado Motor , Feminino , Voluntários Saudáveis , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Condução Nervosa , Estimulação Magnética Transcraniana
10.
Psychol Med ; 45(11): 2413-25, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25804297

RESUMO

BACKGROUND: Postnatal depression affects about 10-15% of women in the year after giving birth. Many women and healthcare professionals would like an effective and accessible non-pharmacological treatment for postnatal depression. METHOD: Women who fulfilled the International Classification of Diseases (ICD)-10 criteria for major depression in the first 6 months postnatally were randomized to receive usual care plus a facilitated exercise intervention or usual care only. The intervention involved two face-to-face consultations and two telephone support calls with a physical activity facilitator over 6 months to support participants to engage in regular exercise. The primary outcome was symptoms of depression using the Edinburgh Postnatal Depression Scale (EPDS) at 6 months post-randomization. Secondary outcomes included EPDS score as a binary variable (recovered and improved) at 6 and 12 months post-randomization. RESULTS: A total of 146 women were potentially eligible and 94 were randomized. Of these, 34% reported thoughts of self-harming at baseline. After adjusting for baseline EPDS, analyses revealed a -2.04 mean difference in EPDS score, favouring the exercise group [95% confidence interval (CI) -4.11 to 0.03, p = 0.05]. When also adjusting for pre-specified demographic variables the effect was larger and statistically significant (mean difference = -2.26, 95% CI -4.36 to -0.16, p = 0.03). Based on EPDS score a larger proportion of the intervention group was recovered (46.5% v. 23.8%, p = 0.03) compared with usual care at 6 months follow-up. CONCLUSIONS: This trial shows that an exercise intervention that involved encouragement to exercise and to seek out social support to exercise may be an effective treatment for women with postnatal depression, including those with thoughts of self-harming.


Assuntos
Depressão Pós-Parto/terapia , Depressão/terapia , Transtorno Depressivo Maior/terapia , Terapia por Exercício/métodos , Adulto , Feminino , Humanos , Escalas de Graduação Psiquiátrica , Comportamento Autodestrutivo , Apoio Social , Inquéritos e Questionários , Resultado do Tratamento , Adulto Jovem
11.
Eur J Cancer Care (Engl) ; 24(5): 618-34, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25630851

RESUMO

Prostate cancer is the second most common cancer in men worldwide, accounting for an estimated 1.1 million new cases diagnosed in 2012 (www.globocan.iarc.fr). Currently, there is a lack of specific guidance on supportive care for men with prostate cancer. This article describes a qualitative systematic review and synthesis examining men's experience of and need for supportive care. Seven databases were searched; 20 journal articles were identified and critically appraised. A thematic synthesis was conducted in which descriptive themes were drawn out of the data. These were peer support, support from partner, online support, cancer specialist nurse support, self-care, communication with health professionals, unmet needs (emotional support, information needs, support for treatment-induced side effects of incontinence and erectile dysfunction) and men's suggestions for improved delivery of supportive care. This was followed by the development of overarching analytic themes which were: uncertainty, reframing, and the timing of receiving treatment, information and support. Our results show that the most valued form of support men experienced following diagnosis was one-to-one peer support and support from partners. This review highlights the need for improved access to cancer specialist nurses throughout the care pathway, individually tailored supportive care and psychosexual support for treatment side effects.


Assuntos
Avaliação das Necessidades , Neoplasias da Próstata/terapia , Apoio Social , Comunicação , Necessidades e Demandas de Serviços de Saúde , Humanos , Masculino , Relações Profissional-Paciente , Neoplasias da Próstata/psicologia
12.
Nutr Metab Cardiovasc Dis ; 24(9): 956-62, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24925122

RESUMO

BACKGROUND AND AIMS: We investigated whether objectively measured sedentary time was associated with markers of inflammation in adults with newly diagnosed type 2 diabetes. METHODS AND RESULTS: We studied 285 adults (184 men, 101 women, mean age 59.0 ± 9.7) who had been recruited to the Early ACTivity in Diabetes (Early ACTID) randomised controlled trial. C-reactive protein (CRP), adiponectin, soluble intracellular adhesion molecule-1 (sICAM-1), interleukin-6 (IL-6), and accelerometer-determined sedentary time and moderate-vigorous physical activity (MVPA) were measured at baseline and after six-months. Linear regression analysis was used to investigate the independent cross-sectional and longitudinal associations of sedentary time with markers of inflammation. At baseline, associations between sedentary time and IL-6 were observed in men and women, an association that was attenuated following adjustment for waist circumference. After 6 months of follow-up, sedentary time was reduced by 0.4 ± 1.2 h per day in women, with the change in sedentary time predicting CRP at follow-up. Every hour decrease in sedentary time between baseline and six-months was associated with 24% (1, 48) lower CRP. No changes in sedentary time between baseline and 6 months were seen in men. CONCLUSIONS: Higher sedentary time is associated with IL-6 in men and women with type 2 diabetes, and reducing sedentary time is associated with improved levels of CRP in women. Interventions to reduce sedentary time may help to reduce inflammation in women with type 2 diabetes.


Assuntos
Biomarcadores/sangue , Diabetes Mellitus Tipo 2/sangue , Inflamação/sangue , Atividade Motora , Comportamento Sedentário , Adiponectina/sangue , Idoso , Índice de Massa Corporal , Proteína C-Reativa/metabolismo , Estudos Transversais , Diabetes Mellitus Tipo 2/diagnóstico , Feminino , Seguimentos , Humanos , Molécula 1 de Adesão Intercelular/sangue , Interleucina-6/sangue , Masculino , Pessoa de Meia-Idade , Circunferência da Cintura
13.
Lett Appl Microbiol ; 59(6): 636-41, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25179583

RESUMO

UNLABELLED: This proof-of-concept study explores the novel use of carbon-based electrodes for the electrochemical generation of hypochlorite and compares the antimicrobial efficacy against commercial hypochlorite solution. Antimicrobial concentrations of hypochlorite were generated using pad-printed carbon and carbon fibre electrodes, yielding up to 0·027% hypochlorite in 60 min and 0·1% hypochlorite in 15 min, respectively, in a nondivided assembly. The minimum inhibitory concentration (MIC) of the electrogenerated hypochlorite produced using carbon fibre electrodes was established for four medically important bacteria (Pseudomonas aeruginosa and Staphylococcus aureus approx. 0·025%, Escherichia coli and Enterococcus faecalis approx. 0·012%) and found to be in agreement with those determined using commercial hypochlorite solution. Therefore, carbon-based electrodes, particularly carbon fibre, have proven effective for the generation of antimicrobial concentrations of hypochlorite. The similarity of the MIC values to commercial hypochlorite solutions suggests that the antimicrobial efficacy is derived from the quantified hypochlorite generated and not due to marked cogeneration of reactive oxygen species, as identified for other assemblies. As such, the application of carbon electrodes may be suitable for the local production of hypochlorite for healthcare antisepsis. SIGNIFICANCE AND IMPACT OF THE STUDY: Carbon fibre electrodes can rapidly generate antimicrobial concentrations of hypochlorite; as such, these cheap and commercially available electrodes are proposed for the local production of hypochlorite for healthcare antisepsis. Importantly, the antimicrobial properties of the electrochemically generated hypochlorite mirror those of commercial hypochlorite, suggesting this is not enhanced by the cogeneration of reactive oxygen species. This illustrates the potential use of disposable carbon electrodes for localized small-volume production of hypochlorite for surface and skin cleansing, and opens a broader scope of research into the exploitation of carbon electrodes for this application.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Desinfetantes/farmacologia , Ácido Hipocloroso/farmacologia , Hipoclorito de Sódio/farmacologia , Carbono , Fibra de Carbono , Eletrodos , Enterococcus faecalis/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
14.
BJOG ; 120(8): 1016-9, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23759087

RESUMO

OBJECTIVE: Recent studies have identified specific symptoms of ovarian cancer at all stages, raising the hope of reducing diagnostic delays. We aimed to devise a scoring system for symptoms of ovarian cancer in primary care. DESIGN: Secondary analysis of data from a case-control study. SETTING: Thirty-nine general practices in Exeter, mid-Devon and east Devon. POPULATION: Two hundred and twelve women with ovarian cancer and 1060 age-, sex- and practice-matched controls. METHODS: Conditional logistic regression was used to produce an additive scoring system and its receiver operator characteristic (ROC) curve. Several different cut-offs were then tested using a simple costs model. MAIN OUTCOME MEASURES: The ROC curve value. RESULTS: Each woman was assigned a score based on her symptoms in the year before diagnosis: we added a score for women aged ≥ 50 years, reflecting their increased incidence of ovarian cancer. The area under the ROC curve was 0.883 (95% confidence interval 0.853-0.912). The chosen cut-off had a sensitivity of 72.6% and a specificity of 91.3%. CONCLUSION: This scoring system could potentially direct general practitioners to appropriate investigations for ovarian cancer on the basis of symptoms and save a substantial number of unnecessary ultrasound scans being requested.


Assuntos
Neoplasias Ovarianas/diagnóstico , Projetos de Pesquisa , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Humanos , Incidência , Modelos Logísticos , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Atenção Primária à Saúde , Curva ROC , Sensibilidade e Especificidade
15.
Indoor Air ; 23(3): 175-84, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23210563

RESUMO

UNLABELLED: Few studies have examined indoor air quality in First Nations communities and its impact on cardiorespiratory health. To address this need, we conducted a crossover study on a First Nations reserve in Manitoba, Canada, including 37 residents in 20 homes. Each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week. Indoor air pollutants were monitored throughout the study period. Indoor PM2.5 decreased substantially during air filter weeks relative to placebo (mean difference: 37 µg/m(3) , 95% CI: 10, 64) but remained approximately five times greater than outdoor concentrations owing to a high prevalence of indoor smoking. On average, air filter use was associated with a 217-ml (95% CI: 23, 410) increase in forced expiratory volume in 1 s, a 7.9-mm Hg (95% CI: -17, 0.82) decrease in systolic blood pressure, and a 4.5-mm Hg (95% CI: -11, 2.4) decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM2.5 and lung function. In general, our findings suggest that reducing indoor PM2.5 may contribute to improved lung function in First Nations communities. PRACTICAL IMPLICATIONS: Indoor air quality is known to contribute to adverse cardiorespiratory health, but few studies have examined indoor air quality in First Nations communities. Our findings suggest that indoor PM2.5 may contribute to reduced lung function and that portable air filters may help to alleviate these effects by effectively reducing indoor levels of particulate matter.


Assuntos
Filtros de Ar , Poluição do Ar em Ambientes Fechados/prevenção & controle , Pressão Sanguínea , Endotélio Vascular/fisiologia , Transtornos Respiratórios/prevenção & controle , Adolescente , Adulto , Criança , Estudos Cross-Over , Método Duplo-Cego , Feminino , Nível de Saúde , Humanos , Indígenas Norte-Americanos/estatística & dados numéricos , Masculino , Manitoba , Pessoa de Meia-Idade , Testes de Função Respiratória , Adulto Jovem
16.
Proc Natl Acad Sci U S A ; 107(13): 6106-11, 2010 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-20220100

RESUMO

Stopping an action in response to an unexpected event requires both that the event is attended to, and that the action is inhibited. Previous neuroimaging investigations of stopping have failed to adequately separate these cognitive elements. Here we used a version of the widely used Stop Signal Task that controls for the attentional capture of stop signals. This allowed us to fractionate the contributions of frontal regions, including the right inferior frontal gyrus and medial frontal cortex, to attentional capture, response inhibition, and error processing. A ventral attentional system, including the right inferior frontal gyrus, has been shown to respond to unexpected stimuli. In line with this evidence, we reasoned that lateral frontal regions support attentional capture, whereas medial frontal regions, including the presupplementary motor area (pre-SMA), actually inhibit the ongoing action. We tested this hypothesis by contrasting the brain networks associated with the presentation of unexpected stimuli against those associated with outright stopping. Functional MRI images were obtained in 26 healthy volunteers. Successful stopping was associated with activation of the right inferior frontal gyrus, as well as the pre-SMA. However, only activation of the pre-SMA differentiated stopping from a high-level baseline that controlled for attentional capture. As expected, unsuccessful attempts at stopping activated the anterior cingulate cortex. In keeping with work in nonhuman primates these findings demonstrate that successful motor inhibition is specifically associated with pre-SMA activation.


Assuntos
Atenção/fisiologia , Lobo Frontal/fisiologia , Adulto , Feminino , Lobo Frontal/anatomia & histologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Atividade Motora/fisiologia , Córtex Motor/anatomia & histologia , Córtex Motor/fisiologia , Estimulação Luminosa , Análise e Desempenho de Tarefas , Adulto Jovem
17.
Diabetologia ; 55(3): 589-99, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22167127

RESUMO

AIMS/HYPOTHESIS: We investigated whether objectively measured sedentary time and interruptions in sedentary time are associated with metabolic factors in people with type 2 diabetes. METHODS: We studied 528 adults (30-80 years) with newly diagnosed type 2 diabetes, who were participants in a diet and physical activity intervention. Waist circumference (WC), fasting HDL-cholesterol, insulin and glucose levels, HOMA of insulin resistance (HOMA-IR) and physical activity (accelerometer) were measured at baseline and at 6 months follow-up. Linear regression models were used to investigate cross-sectional and longitudinal associations of accelerometer-derived sedentary time and breaks in sedentary time (BST) with metabolic variables. RESULTS: In cross-sectional analyses each hour of sedentary time was associated with larger WC (unstandardised regression coefficient [B] [95% CI] 1.89 cm [0.94, 2.83]; p < 0.001), higher insulin (B = 8.22 pmol/l [2.80, 13.65]; p = 0.003) and HOMA-IR (B = 0.42 [0.14, 0.70]; p = 0.004), and lower HDL-cholesterol (B = -0.04 mmol/l [-0.06, -0.01]; p = 0.005). Adjustment for WC attenuated all associations. Each BST was associated with lower WC (B = -0.15 cm [- 0.24, -0.05]; p = 0.003) and there was evidence of a weak linear association with HDL-cholesterol, but no association with insulin levels or HOMA-IR. Volume of sedentary time at baseline predicted HDL-cholesterol (B = -0.05 mmol/l [-0.08, -0.01]; p = 0.007), insulin levels (B = 8.14 pmol/l [0.1.51, 14.78]; p = 0.016) and HOMA-IR (B = 0.49 [0.08, 0.90]; p = 0.020) at 6 months, though not WC. Baseline BST did not substantially predict any metabolic variables at follow-up. No change was seen in sedentary time or BST between baseline and 6 months follow-up. CONCLUSIONS/INTERPRETATION: Higher sedentary time is associated with a poorer metabolic profile in people with type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/terapia , Atividade Motora , Comportamento Sedentário , Adulto , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , HDL-Colesterol/sangue , Estudos de Coortes , Estudos Transversais , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Inglaterra , Feminino , Humanos , Insulina/sangue , Resistência à Insulina , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Sobrepeso/complicações , Cooperação do Paciente , Fatores de Tempo , Adulto Jovem
18.
Lancet ; 378(9786): 129-39, 2011 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-21705068

RESUMO

BACKGROUND: Lifestyle changes soon after diagnosis might improve outcomes in patients with type 2 diabetes mellitus, but no large trials have compared interventions. We investigated the effects of diet and physical activity on blood pressure and glucose concentrations. METHODS: We did a randomised, controlled trial in southwest England in adults aged 30-80 years in whom type 2 diabetes had been diagnosed 5-8 months previously. Participants were assigned usual care (initial dietary consultation and follow-up every 6 months; control group), an intensive diet intervention (dietary consultation every 3 months with monthly nurse support), or the latter plus a pedometer-based activity programme, in a 2:5:5 ratio. The primary endpoint was improvement in glycated haemoglobin A(1c)(HbA(1c)) concentration and blood pressure at 6 months. Analysis was done by intention to treat. This study is registered, number ISRCTN92162869. FINDINGS: Of 593 eligible individuals, 99 were assigned usual care, 248 the diet regimen, and 246 diet plus activity. Outcome data were available for 587 (99%) and 579 (98%) participants at 6 and 12 months, respectively. At 6 months, glycaemic control had worsened in the control group (mean baseline HbA(1c) percentage 6·72, SD 1·02, and at 6 months 6·86, 1·02) but improved in the diet group (baseline-adjusted difference in percentage of HbA(1c) -0·28%, 95% CI -0·46 to -0·10; p=0·005) and diet plus activity group (-0·33%, -0·51 to -0·14; p<0·001). These differences persisted to 12 months, despite less use of diabetes drugs. Improvements were also seen in bodyweight and insulin resistance between the intervention and control groups. Blood pressure was similar in all groups. INTERPRETATION: An intensive diet intervention soon after diagnosis can improve glycaemic control. The addition of an activity intervention conferred no additional benefit. FUNDING: Diabetes UK and the UK Department of Health.


Assuntos
Diabetes Mellitus Tipo 2/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada , Diabetes Mellitus Tipo 2/dietoterapia , Terapia por Exercício , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Análise de Intenção de Tratamento , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Redução de Peso
19.
Phys Rev Lett ; 108(2): 022501, 2012 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-22324674

RESUMO

The quantitative consistency of nucleon transfer reactions as a probe of the occupancy of valence orbits in nuclei is tested. Neutron-adding, neutron-removal, and proton-adding transfer reactions were measured on the four stable even Ni isotopes, with particular attention to the cross section determinations. The data were analyzed consistently in terms of the distorted wave Born approximation to yield spectroscopic factors. Valence-orbit occupancies were extracted, utilizing the Macfarlane-French sum rules. The deduced occupancies are consistent with the changing number of valence neutrons, as are the vacancies for protons, both at the level of <5%. While there has been some debate regarding the true "observability" of spectroscopic factors, the present results indicate that empirically they yield self-consistent results.

20.
Br J Psychiatry ; 200(3): 238-44, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22282432

RESUMO

BACKGROUND: Psilocybin is a classic psychedelic drug that has a history of use in psychotherapy. One of the rationales for its use was that it aids emotional insight by lowering psychological defences. AIMS: To test the hypothesis that psilocybin facilitates access to personal memories and emotions by comparing subjective and neural responses to positive autobiographical memories under psilocybin and placebo. METHOD: Ten healthy participants received two functional magnetic resonance imaging scans (2 mg intravenous psilocybin v. intravenous saline), separated by approximately 7 days, during which they viewed two different sets of 15 positive autobiographical memory cues. Participants viewed each cue for 6 s and then closed their eyes for 16 s and imagined re-experiencing the event. Activations during this recollection period were compared with an equivalent period of eyes-closed rest. We split the recollection period into an early phase (first 8 s) and a late phase (last 8 s) for analysis. RESULTS: Robust activations to the memories were seen in limbic and striatal regions in the early phase and the medial prefrontal cortex in the late phase in both conditions (P<0.001, whole brain cluster correction), but there were additional visual and other sensory cortical activations in the late phase under psilocybin that were absent under placebo. Ratings of memory vividness and visual imagery were significantly higher after psilocybin (P<0.05) and there was a significant positive correlation between vividness and subjective well-being at follow-up (P<0.01). CONCLUSIONS: Evidence that psilocybin enhances autobiographical recollection implies that it may be useful in psychotherapy either as a tool to facilitate the recall of salient memories or to reverse negative cognitive biases.


Assuntos
Emoções/efeitos dos fármacos , Alucinógenos/uso terapêutico , Imageamento por Ressonância Magnética/métodos , Memória/efeitos dos fármacos , Psilocibina/uso terapêutico , Adulto , Encéfalo/fisiologia , Mapeamento Encefálico , Terapia Combinada , Estudos Cross-Over , Feminino , Alucinógenos/farmacologia , Humanos , Masculino , Memória/fisiologia , Memória Episódica , Placebos , Psilocibina/farmacologia , Psicoterapia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA