1,564 research outputs found
The dissimilarity map and representation theory of
We give another proof that -dissimilarity vectors of weighted trees are
points on the tropical Grassmanian, as conjectured by Cools, and proved by
Giraldo in response to a question of Sturmfels and Pachter. We accomplish this
by relating -dissimilarity vectors to the representation theory of Comment: 11 pages, 8 figure
Automatic segmentation of MR brain images with a convolutional neural network
Automatic segmentation in MR brain images is important for quantitative
analysis in large-scale studies with images acquired at all ages.
This paper presents a method for the automatic segmentation of MR brain
images into a number of tissue classes using a convolutional neural network. To
ensure that the method obtains accurate segmentation details as well as spatial
consistency, the network uses multiple patch sizes and multiple convolution
kernel sizes to acquire multi-scale information about each voxel. The method is
not dependent on explicit features, but learns to recognise the information
that is important for the classification based on training data. The method
requires a single anatomical MR image only.
The segmentation method is applied to five different data sets: coronal
T2-weighted images of preterm infants acquired at 30 weeks postmenstrual age
(PMA) and 40 weeks PMA, axial T2- weighted images of preterm infants acquired
at 40 weeks PMA, axial T1-weighted images of ageing adults acquired at an
average age of 70 years, and T1-weighted images of young adults acquired at an
average age of 23 years. The method obtained the following average Dice
coefficients over all segmented tissue classes for each data set, respectively:
0.87, 0.82, 0.84, 0.86 and 0.91.
The results demonstrate that the method obtains accurate segmentations in all
five sets, and hence demonstrates its robustness to differences in age and
acquisition protocol
Feel My Pain: Design and Evaluation of Painpad, a Tangible Device for Supporting Inpatient Self-Logging of Pain
Monitoring patients' pain is a critical issue for clinical caregivers, particularly among staff responsible for providing analgesic relief. However, collecting regularly scheduled pain readings from patients can be difficult and time-consuming for clinicians. In this paper we present Painpad, a tangible device that was developed to allow patients to engage in self-logging of their pain. We report findings from two hospital-based field studies in which Painpad was deployed to a total of 78 inpatients recovering from ambulatory surgery. We find that Painpad results in improved frequency and compliance with pain logging, and that self-logged scores may be more faithful to patients' experienced pain than corresponding scores reported to nurses. We also show that older adults may prefer tangible interfaces over tablet-based alternatives for reporting their pain, and we contribute design lessons for pain logging devices intended for use in hospital settings
Bleeding Diathesis in Fawn Hooded Rats:Possible Implications for Invasive Procedures and Refinement Strategies
The Fawn hooded (FH) rat is commonly used in biomedical research. It is widely acknowledged that the FH rat has a bleeding disorder; leading to abundant bleedings. Although this bleeding disorder is investigated to model the storage pool defect; its impact on commonly performed invasive laboratory procedures has not yet been described. Our research group experienced clinically significant consequences of this bleeding disorder following invasive procedures (including intraperitoneal injections and neurocranial surgery) in the Rjlbm: FH stock. The clinical consequences of the surgical and anesthetic protocols applied; are described including the subsequent procedural refinements applied to minimize the impact of this disorder. It is strongly recommended to take the bleeding diathesis into account when performing invasive procedures in FH rats and to apply the suggested refinement of procedures
Five pathways into one profession:Fifty years of debate on differentiated nursing practice
The persistence of multiple educational pathways into the nursing profession continues to occupy scholars internationally. In the Netherlands, various groups within the Dutch healthcare sector have tried to differentiate nursing practice on the basis of educational backgrounds for over 50 years. Proponents argue that such reforms are needed to retain bachelor-trained nurses, improve quality of care and strengthen nurses' position in the sector. Opponents have actively resisted reforms because they would mainly benefit bachelor-trained nurses and neglect practical experience and technical skills. This historical case study aims to provide insight in this apparent stalemate. Our analysis of this debate is informed by literature on institutional work and current debates within the historiography of nursing. This study contributes to a better understanding of this contemporary debate by examining a broader timeframe than is usually studied, and by highlighting nurses' roles in complex processes of change. We argue that, rather than being stuck in their professional development, different groups of nurses have forged their own path forward in their professional development, albeit via different strategies.</p
Five pathways into one profession:Fifty years of debate on differentiated nursing practice
The persistence of multiple educational pathways into the nursing profession continues to occupy scholars internationally. In the Netherlands, various groups within the Dutch healthcare sector have tried to differentiate nursing practice on the basis of educational backgrounds for over 50 years. Proponents argue that such reforms are needed to retain bachelor-trained nurses, improve quality of care and strengthen nurses' position in the sector. Opponents have actively resisted reforms because they would mainly benefit bachelor-trained nurses and neglect practical experience and technical skills. This historical case study aims to provide insight in this apparent stalemate. Our analysis of this debate is informed by literature on institutional work and current debates within the historiography of nursing. This study contributes to a better understanding of this contemporary debate by examining a broader timeframe than is usually studied, and by highlighting nurses' roles in complex processes of change. We argue that, rather than being stuck in their professional development, different groups of nurses have forged their own path forward in their professional development, albeit via different strategies.</p
Imaging features of COVID-19-associated secondary sclerosing cholangitis on magnetic resonance cholangiopancreatography: a retrospective analysis
Background: Despite emerging reports of secondary sclerosing cholangitis (SSC) in critically ill COVID-19 patients little is known about its imaging findings. It presents as delayed progressive cholestatic liver injury with risk of progression to cirrhosis. Diagnosis cannot be made based on clinical presentation and laboratory markers alone. Magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography (MRCP) can aid in the diagnosis. The aim of this study was to describe MRI/MRCP imaging features of COVID-19-associated SSC.
Results: Seventeen patients (mean age 60.5 years, 15 male) who underwent MRI/MRCP were included. All had been admitted to intensive care unit (ICU) (median duration of ICU stay 10 weeks, range, 2-28 weeks) and developed acute respiratory distress syndrome requiring mechanical ventilation. On imaging, all patients had intrahepatic bile duct strictures and 10 (58.8%) had associated upstream dilatation. Intrahepatic bile duct beading was seen in 14 cases (82.3%). Only one patient (5.9%) had extrahepatic bile duct stricturing. Patchy arterial phase hyperenhancement and high signal on T2- and diffusion-weighted images were seen in 7 cases (53.8%) and 9 cases (52.9%), respectively. Biliary casts were seen in 2 cases (11.8%). Periportal lymphadenopathy and vascular complications were not seen.
Conclusion: On MRI/MRCP, COVID-19-associated SSC presents with multiple intrahepatic bile duct strictures with or without upstream dilatation and intrahepatic bile duct beading. Surrounding hepatic parenchymal changes including alterations in enhancement and T2 signal are common. The extrahepatic biliary tree was typically spared and periportal lymphadenopathy was missing in all patients.
Keywords: COVID-19; Cholangiopancreatography; Cholangitis; Magnetic resonance; Sclerosin
Bax mitochondrial relocation is linked to its phosphorylation and its interaction with Bcl-xL
The heterologous expression of Bax, and other Bcl-2 family members, in the yeast Saccharomyces cerevisiae, has proved to be a valuable reporter system to investigate the molecular mechanisms underlying their interaction with mitochondria. By combining the co-expression of Bax and Bcl-xL mutants with analyzes of their localization and interaction in mitochondria and post-mitochondrial supernatants, we showed that the ability of Bax and Bcl-xL to interact is dependent both on Bax phosphorylation – mimicked by a substitution S184D – and by Bax and Bcl-xL localization. This, and previous data, provide the molecular basis for a model of dynamic equilibrium for Bax localization and activation, regulated both by phosphorylation and Bcl-xL
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