578 research outputs found
Conservative and disruptive modes of adolescent change in human brain functional connectivity
Adolescent changes in human brain function are not entirely understood. Here, we used multiecho functional MRI (fMRI) to measure developmental change in functional connectivity (FC) of resting-state oscillations between pairs of 330 cortical regions and 16 subcortical regions in 298 healthy adolescents scanned 520 times. Participants were aged 14 to 26 y and were scanned on 1 to 3 occasions at least 6 mo apart. We found 2 distinct modes of age-related change in FC: “conservative” and “disruptive.” Conservative development was characteristic of primary cortex, which was strongly connected at 14 y and became even more connected in the period from 14 to 26 y. Disruptive development was characteristic of association cortex and subcortical regions, where connectivity was remodeled: connections that were weak at 14 y became stronger during adolescence, and connections that were strong at 14 y became weaker. These modes of development were quantified using the maturational index (MI), estimated as Spearman’s correlation between edgewise baseline FC (at 14 y, FC14) and adolescent change in FC (ΔFC14−26), at each region. Disruptive systems (with negative MI) were activated by social cognition and autobiographical memory tasks in prior fMRI data and significantly colocated with prior maps of aerobic glycolysis (AG), AG-related gene expression, postnatal cortical surface expansion, and adolescent shrinkage of cortical thickness. The presence of these 2 modes of development was robust to numerous sensitivity analyses. We conclude that human brain organization is disrupted during adolescence by remodeling of FC between association cortical and subcortical areas
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Investigation of the in-vitro loading on an artificial spinal disk prosthesis
Spinal diseases imposes considerable burden to both patients and society. In recent years, much surgical efforts have been made in advancing the treatment of neck and back pain. Of particular prominence is the increasing clinical acceptance and use of intervertebral artificial disk prosthesis for the treatment of discogenic back pain. Despite this increased use of such disks, their in-vivo monitoring remains rudimentary. In an effort to develop an intelligent artificial spinal disk where the in-vivo loading of the spine can by studied for the first time an experimental set up has been created in order to initially study the in-vitro loading on an artificial disc prosthesis. Eight strain gauges and two piezoresistive sensors were used and placed suitably in the artificial disk prosthesis. The results from the in-vitro loading showed linear relationship between loading and the outputs from the sensors with good repeatability and less hysteresis
Under pressure: Response urgency modulates striatal and insula activity during decision-making under risk
When deciding whether to bet in situations that involve potential monetary loss or gain (mixed gambles), a subjective sense of pressure can influence the evaluation of the expected utility associated with each choice option. Here, we explored how gambling decisions, their psychophysiological and neural counterparts are modulated by an induced sense of urgency to respond. Urgency influenced decision times and evoked heart rate responses, interacting with the expected value of each gamble. Using functional MRI, we observed that this interaction was associated with changes in the activity of the striatum, a critical region for both reward and choice selection, and within the insula, a region implicated as the substrate of affective feelings arising from interoceptive signals which influence motivational behavior. Our findings bridge current psychophysiological and neurobiological models of value representation and action-programming, identifying the striatum and insular cortex as the key substrates of decision-making under risk and urgency
P-V criticality of charged AdS black holes
Treating the cosmological constant as a thermodynamic pressure and its
conjugate quantity as a thermodynamic volume, we reconsider the critical
behaviour of charged AdS black holes. We complete the analogy of this system
with the liquid-gas system and study its critical point, which occurs at the
point of divergence of specific heat at constant pressure. We calculate the
critical exponents and show that they coincide with those of the Van der Waals
system.Comment: 13 pages, 15 figures, v2:added reference
Social and ethical criteria for prioritizing patients: a survey of students and health professionals in Portugal
O estudo quali-quantitativo explora
o dilema ético da microalocação dos recursos da
saúde. Objetiva identificar e comparar a opinião
de dois grupos da sociedade portuguesa - estudantes
e profissionais de saúde sobre a importância
das características pessoais dos pacientes no momento
de os priorizar e se as escolhas se explicam
por referenciais bioéticos de caráter utilitaristas ou
deontológicos. Os dados foram recolhidos através
de um questionário aplicado a uma amostra de
180 estudantes universitários e 60 profissionais de
saúde. Os respondentes perante hipotéticos cená-
rios de emergência clínica tiveram de escolher de
entre dois pacientes (distinguidos por idade, sexo,
responsabilidade social, situação económica e laboral,
comportamentos lesivos da saúde e registo
criminal) quem tratar e justificar a escolha. Foram
usados testes estatísticos de associação para
comparar as respostas dos dois grupos e análise
de conteúdo para categorizar as justificações. Os
resultados sugerem a existência de diferenças nas
escolhas dos dois grupos, com os profissionais de
saúde a revelarem aceitar menos a utilização de
critérios sociais em contexto de escassez e coexistência
de critérios utilitaristas e deontológicos,
com predomínio da eficiência por parte dos profissionais
de saúde e da equidade por parte dos
estudantesThis qualitative/quantitative study examines
the ethical dilemma of microallocation of
health resources. It seeks to identify and compare
the opinion of two groups in Portuguese society
– students and health professionals – on the importance
of personal characteristics of patients at
the moment of prioritizing them and if the choices
can be explained by bioethical references of a
utilitarian or deontological nature. Data were
collected by means of a questionnaire administered
to a sample of 180 students and 60 health
professionals. Faced with hypothetical emergency
scenarios, the respondents had to choose between
two patients (distinguished by: age, gender, social
responsibility, economic and employment
situation, harmful health behaviors and criminal
record), duly selecting who to treat and then
justifying their choice. The results suggest the existence
of differences in choices between the two
groups, with health professionals revealing they
are less prepared to accept the use of social criteria
in a context of scarce resources and co-existence
of utilitarian and deontological criteria, with a
predominance of efficiency on the part of health
professionals and equity on the part of students.info:eu-repo/semantics/publishedVersio
User needs elicitation via analytic hierarchy process (AHP). A case study on a Computed Tomography (CT) scanner
Background:
The rigorous elicitation of user needs is a crucial step for both medical device design and purchasing. However, user needs elicitation is often based on qualitative methods whose findings can be difficult to integrate into medical decision-making. This paper describes the application of AHP to elicit user needs for a new CT scanner for use in a public hospital.
Methods:
AHP was used to design a hierarchy of 12 needs for a new CT scanner, grouped into 4 homogenous categories, and to prepare a paper questionnaire to investigate the relative priorities of these. The questionnaire was completed by 5 senior clinicians working in a variety of clinical specialisations and departments in the same Italian public hospital.
Results:
Although safety and performance were considered the most important issues, user needs changed according to clinical scenario. For elective surgery, the five most important needs were: spatial resolution, processing software, radiation dose, patient monitoring, and contrast medium. For emergency, the top five most important needs were: patient monitoring, radiation dose, contrast medium control, speed run, spatial resolution.
Conclusions:
AHP effectively supported user need elicitation, helping to develop an analytic and intelligible framework of decision-making. User needs varied according to working scenario (elective versus emergency medicine) more than clinical specialization. This method should be considered by practitioners involved in decisions about new medical technology, whether that be during device design or before deciding whether to allocate budgets for new medical devices according to clinical functions or according to hospital department
Gauge gravity duality for d-wave superconductors: prospects and challenges
We write down an action for a charged, massive spin two field in a fixed
Einstein background. Despite some technical problems, we argue that in an
effective field theory framework and in the context of the AdS/CFT
correspondence, this action can be used to study the properties of a superfluid
phase transition with a d-wave order parameter in a dual strongly interacting
field theory. We investigate the phase diagram and the charge conductivity of
the superfluid phase. We also explain how possible couplings between the spin
two field and bulk fermions affect the fermion spectral function.Comment: 42 pages, 6 figure
Symptoms and quality of life in late stage Parkinson syndromes: a longitudinal community study of predictive factors
BACKGROUND
Palliative care is increasingly offered earlier in the cancer trajectory but rarely in Idiopathic Parkinson's Disease(IPD), Progressive Supranuclear Palsy(PSP) or Multiple System Atrophy(MSA). There is little longitudinal data of people with late stage disease to understand levels of need. We aimed to determine how symptoms and quality of life of these patients change over time; and what demographic and clinical factors predicted changes.
METHODS
We recruited 82 patients into a longitudinal study, consenting patients with a diagnosis of IPD, MSA or PSP, stages 3-5 Hoehn and Yahr(H&Y). At baseline and then on up to 3 occasions over one year, we collected self-reported demographic, clinical, symptom, palliative and quality of life data, using Parkinson's specific and generic validated scales, including the Palliative care Outcome Scale (POS). We tested for predictors using multivariable analysis, adjusting for confounders.
FINDINGS
Over two thirds of patients had severe disability, over one third being wheelchair-bound/bedridden. Symptoms were highly prevalent in all conditions - mean (SD) of 10.6(4.0) symptoms. More than 50% of the MSA and PSP patients died over the year. Over the year, half of the patients showed either an upward (worsening, 24/60) or fluctuant (8/60) trajectory for POS and symptoms. The strongest predictors of higher levels of symptoms at the end of follow-up were initial scores on POS (AOR 1.30; 95%CI:1.05-1.60) and being male (AOR 5.18; 95% CI 1.17 to 22.92), both were more predictive than initial H&Y scores.
INTERPRETATION
The findings point to profound and complex mix of non-motor and motor symptoms in patients with late stage IPD, MSA and PSP. Symptoms are not resolved and half of the patients deteriorate. Palliative problems are predictive of future symptoms, suggesting that an early palliative assessment might help screen for those in need of earlier intervention
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