189 research outputs found
Classification of head impacts based on the spectral density of measurable kinematics
Traumatic brain injury can be caused by head impacts, but many brain injury
risk estimation models are less accurate across the variety of impacts that
patients may undergo. We investigated the spectral characteristics of different
head impact types with kinematics classification. Data was analyzed from 3,262
head impacts from lab reconstruction, American football, mixed martial arts,
and publicly available car crash data. A random forest classifier with spectral
densities of linear acceleration and angular velocity was built to classify
head impact types (e.g., football), reaching a median accuracy of 96% over
1,000 random partitions of training and test sets. To test the classifier on
data from different measurement devices, another 271 lab-reconstructed impacts
were obtained from 5 other instrumented mouthguards with the classifier
reaching over 96% accuracy. The most important features in the classification
included both low-frequency and high-frequency features, both linear
acceleration features and angular velocity features. Different head impact
types had different distributions of spectral densities in low-frequency and
high-frequency ranges (e.g., the spectral densities of MMA impacts were higher
in high-frequency range than in the low-frequency range). Finally, with the
classifier, type-specific, nearest-neighbor regression models were built for
95th percentile maximum principal strain, 95th percentile maximum principal
strain in corpus callosum, and cumulative strain damage (15th percentile). This
showed a generally higher R2-value than baseline models. The classifier enables
a better understanding of the impact kinematics in different sports, and it can
be applied to evaluate the quality of impact-simulation systems and on-field
data augmentation. Key words: traumatic brain injury, head impacts,
classification, impact kinematicsComment: 16 pages, 5 figure
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Amyloid-β nanotubes are associated with prion protein-dependent synaptotoxicity
Growing evidence suggests water-soluble, non-fibrillar forms of amyloid-β protein (Aβ) have important roles in Alzheimer’s disease with toxicities mimicked by synthetic Aβ1–42. However, no defined toxic structures acting via specific receptors have been identified and roles of proposed receptors, such as prion protein (PrP), remain controversial. Here we quantify binding to PrP of Aβ1–42 after different durations of aggregation. We show PrP-binding and PrP-dependent inhibition of long-term potentiation (LTP) correlate with the presence of protofibrils. Globular oligomers bind less avidly to PrP and do not inhibit LTP, whereas fibrils inhibit LTP in a PrP-independent manner. That only certain transient Aβ assemblies cause PrP-dependent toxicity explains conflicting reports regarding the involvement of PrP in Aβ-induced impairments. We show that these protofibrils contain a defined nanotubular structure with a previously unidentified triple helical conformation. Blocking the formation of Aβ nanotubes or their interaction with PrP might have a role in treatment of Alzheimer’s disease
Multi-directional dynamic model for traumatic brain injury detection
Traumatic brain injury (TBI) is a complex injury that is hard to predict and
diagnose, with many studies focused on associating head kinematics to brain
injury risk. Recently, there has been a push towards using computationally
expensive finite element (FE) models of the brain to create tissue deformation
metrics of brain injury. Here, we developed a 3 degree-of-freedom
lumped-parameter brain model, built based on the measured natural frequencies
of a FE brain model simulated with live human impact data, to be used to
rapidly estimate peak brain strains experienced during head rotational
accelerations. On our dataset, the simplified model correlates with peak
principal FE strain by an R2 of 0.80. Further, coronal and axial model
displacement correlated with fiber-oriented peak strain in the corpus callosum
with an R2 of 0.77. Using the maximum displacement predicted by our brain
model, we propose an injury criteria and compare it against a number of
existing rotational and translational kinematic injury metrics on a dataset of
head kinematics from 27 clinically diagnosed injuries and 887 non-injuries. We
found that our proposed metric performed comparably to peak angular
acceleration, linear acceleration, and angular velocity in classifying injury
and non-injury events. Metrics which separated time traces into their
directional components had improved deviance to those which combined components
into a single time trace magnitude. Our brain model can be used in future work
as a computationally efficient alternative to FE models for classifying
injuries over a wide range of loading conditions.Comment: 10 figures, 3 table
Predictive Factors of Kinematics in Traumatic Brain Injury from Head Impacts Based on Statistical Interpretation
Brain tissue deformation resulting from head impacts is primarily caused by
rotation and can lead to traumatic brain injury. To quantify brain injury risk
based on measurements of kinematics on the head, finite element (FE) models and
various brain injury criteria based on different factors of these kinematics
have been developed, but the contribution of different kinematic factors has
not been comprehensively analyzed across different types of head impacts in a
data-driven manner. To better design brain injury criteria, the predictive
power of rotational kinematics factors, which are different in 1) the
derivative order (angular velocity, angular acceleration, angular jerk), 2) the
direction and 3) the power (e.g., square-rooted, squared, cubic) of the angular
velocity, were analyzed based on different datasets including laboratory
impacts, American football, mixed martial arts (MMA), NHTSA automobile
crashworthiness tests and NASCAR crash events. Ordinary least squares
regressions were built from kinematics factors to the 95\% maximum principal
strain (MPS95), and we compared zero-order correlation coefficients, structure
coefficients, commonality analysis, and dominance analysis. The angular
acceleration, the magnitude, and the first power factors showed the highest
predictive power for the majority of impacts including laboratory impacts,
American football impacts, with few exceptions (angular velocity for MMA and
NASCAR impacts). The predictive power of rotational kinematics in three
directions (x: posterior-to-anterior, y: left-to-right, z:
superior-to-inferior) of kinematics varied with different sports and types of
head impacts
Analysing NSW state policy for child obesity prevention: strategic policy versus practical action
There is increasing worldwide recognition of the need for government policies to address the recent increases in the incidence and prevalence of childhood obesity. The complexity and inter-relatedness of the determinants of obesity pose a genuine policy challenge, both scientifically and politically. This study examines the characteristics of one of the early policy responses, the NSW Government\u27s Prevention of Obesity in Children and Young People: NSW Government Action Plan 2003-2007 (GAP), as a case study, assessing it in terms of its content and capacity for implementation. This policy was designed as an initial set of practical actions spanning five government sectors. Most of the policy actions fitted with existing implementation systems within NSW government, and reflected an incremental approach to policy formulation and implementation. As a case study, the NSW Government Action Plan illustrates that childhood obesity policy development and implementation are at an early stage. This policy, while limited, may have built sufficient commitment and support to create momentum for more strategic policy in the future. A more sophisticated, comprehensive and strategic policy which can also be widely implemented and evaluated should now be built on this base
The support needs of terminally ill people living alone at home: a narrative review
Context: The number of terminally ill people who live alone at home and without a caregiver is growing and exerting pressure on the stretched resources of home-based palliative care services. Objectives: We aimed to highlight the unmet support needs of terminally ill people who live alone at home and have no primary caregiver and identify specific models of care that have been used to address these gaps. Methods: We conducted a narrative review of empirical research published in peer-reviewed journals in English using a systematic approach, searching databases 2002–2013. This review identified 547 abstracts as being potentially relevant. Of these, 95 were retrieved and assessed, with 37 studies finally reviewed. Results: Majority of the studies highlighted the reduced likelihood of this group to be cared for and die at home and the experiences of more psychosocial distress and more hospital admissions than people with a primary caregiver. Few studies reported on the development of models of care but showed that the challenges faced by this group may be mitigated by interventions tailored to meet their specific needs. Conclusion: This is the first review to highlight the growing challenges facing community palliative care services in supporting the increasing number of people living alone who require care. There is a need for more studies to examine the effectiveness of informal support networks and suitable models of care and to provide directions that will inform service planning for this growing and challenging group
Challenges in supporting lay carers of patients at the end of life: results from focus group discussions with primary healthcare providers
Background: Family caregivers (FCGs) of patients at the end of life (EoL) cared for at home receive support from professional and non-professional care providers. Healthcare providers in general practice play an important role as they coordinate care and establish contacts between the parties concerned. To identify potential intervention targets, this study deals with the challenges healthcare providers in general practice face in EoL care situations including patients, caregivers and networks.
Methods: Focus group discussions with general practice teams in Germany were conducted to identify barriers to and enablers of an optimal support for family caregivers. Focus group discussions were analysed using content analysis.
Results: Nineteen providers from 11 general practices took part in 4 focus group discussions. Participants identified challenges in communication with patients, caregivers and within the professional network. Communication with patients and caregivers focused on non-verbal messages, communicating at an appropriate time and perceiving patient and caregiver as a unit of care. Practice teams perceive themselves as an important part of the healthcare network, but also report difficulties in communication and cooperation with other healthcare providers.
Conclusion: Healthcare providers in general practice identified relational challenges in daily primary palliative care with potential implications for EoL care. Communication and collaboration with patients, caregivers and among healthcare providers give opportunities for improving palliative care with a focus on the patient-caregiver dyad. It is insufficient to demand a (professional) support network; existing structures need to be recognized and included into the care
What Lies behind the Wish to Hasten Death? A Systematic Review and Meta-Ethnography from the Perspective of Patients
BACKGROUND: There is a need for an in-depth approach to the meaning of the wish to hasten death (WTHD). This study aims to understand the experience of patients with serious or incurable illness who express such a wish. METHODS AND FINDINGS: Systematic review and meta-ethnography of qualitative studies from the patient's perspective. Studies were identified through six databases (ISI, PubMed, PsycINFO, CINAHL, CUIDEN and the Cochrane Register of Controlled Trials), together with citation searches and consultation with experts. Finally, seven studies reporting the experiences of 155 patients were included. The seven-stage Noblit and Hare approach was applied, using reciprocal translation and line-of-argument synthesis. Six main themes emerged giving meaning to the WTHD: WTHD in response to physical/psychological/spiritual suffering, loss of self, fear of dying, the desire to live but not in this way, WTHD as a way of ending suffering, and WTHD as a kind of control over one's life ('having an ace up one's sleeve just in case'). An explanatory model was developed which showed the WTHD to be a reactive phenomenon: a response to multidimensional suffering, rather than only one aspect of the despair that may accompany this suffering. According to this model the factors that lead to the emergence of WTHD are total suffering, loss of self and fear, which together produce an overwhelming emotional distress that generates the WTHD as a way out, i.e. to cease living in this way and to put an end to suffering while maintaining some control over the situation. CONCLUSIONS: The expression of the WTHD in these patients is a response to overwhelming emotional distress and has different meanings, which do not necessarily imply a genuine wish to hasten one's death. These meanings, which have a causal relationship to the phenomenon, should be taken into account when drawing up care plans
Interest groups in multiple streams:specifying their involvement in the framework
Although interests inhabit a central place in the multiple streams framework (MSF), interest groups have played only a minor role in theoretical and empirical studies until now. In Kingdon’s original conception, organized interests are a key variable in the politics stream. Revisiting Kingdon’s concept with a particular focus on interest groups and their activities—in different streams and at various levels—in the policy process, we take this argument further. In particular, we argue that specifying groups’ roles in other streams adds value to the explanatory power of the framework. To do this, we look at how interest groups affect problems, policies, and politics. The influence of interest groups within the streams is explained by linking the MSF with literature on interest intermediation. We show that depending on the number of conditions and their activity level, interest groups can be involved in all three streams. We illustrate this in case studies reviewing labor market policies in Germany and chemicals regulation at the European level
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