946 resultados para medical imaging


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This article is the second part of a two-part series examining securement options for commonly used therapeutic devices in the adult intensive care unit. Part A focused on endotracheal device securement.1 This article addresses nasogastric tube (NGT) securement options and with the aim of identifying the available range of NGT securement devices in Australia as a resource for clinicians seeking to explore options for tube stabilisation. Nasogastric feeding or gastric decompression tubes are commonly inserted via the nostril/nares. The National Pressure Ulcer Advisory Panel (NPUAP) 2011 position statement on mucosal pressure injuries, highlighted that mucosal tissues are vulnerable to pressure from devices.2 Securing of these devices sometimes leads to pressure-related injury to the internal mucosa due to difficulty visualising the mucosa and failure to reposition the nasogastric tube to relieve the pressure in a particular area.3 The nasal orifice is much smaller than the oral cavity and regular tube position changes are vital to minimise the risk of mucosal damage and ulcer development.

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OBJECTIVE To investigate the impact of new-onset diabetic ketoacidosis (DKA) during child- hood on brain morphology and function. RESEARCH DESIGN AND METHODS Patients aged 6–18 years with and without DKA at diagnosis were studied at four time points: <48 h, 5 days, 28 days, and 6 months postdiagnosis. Patients under- went magnetic resonance imaging (MRI) and spectroscopy with cognitive assess- ment at each time point. Relationships between clinical characteristics at presentation and MRI and neurologic outcomes were examined using multiple linear regression, repeated-measures, and ANCOVA analyses. RESULTS Thirty-six DKA and 59 non-DKA patients were recruited between 2004 and 2009. With DKA, cerebral white matter showed the greatest alterations with increased total white matter volume and higher mean diffusivity in the frontal, temporal, and parietal white matter. Total white matter volume decreased over the first 6 months. For gray matter in DKA patients, total volume was lower at baseline and increased over 6 months. Lower levels of N-acetylaspartate were noted at base- line in the frontal gray matter and basal ganglia. Mental state scores were lower at baseline and at 5 days. Of note, although changes in total and regional brain volumes over the first 5 days resolved, they were associated with poorer delayed memory recall and poorer sustained and divided attention at 6 months. Age at time of presentation and pH level were predictors of neuroimaging and functional outcomes. CONCLUSIONS DKA at type 1 diabetes diagnosis results in morphologic and functional brain changes. These changes are associated with adverse neurocognitive outcomes in the medium term.

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Facial expression recognition (FER) has been dramatically developed in recent years, thanks to the advancements in related fields, especially machine learning, image processing and human recognition. Accordingly, the impact and potential usage of automatic FER have been growing in a wide range of applications, including human-computer interaction, robot control and driver state surveillance. However, to date, robust recognition of facial expressions from images and videos is still a challenging task due to the difficulty in accurately extracting the useful emotional features. These features are often represented in different forms, such as static, dynamic, point-based geometric or region-based appearance. Facial movement features, which include feature position and shape changes, are generally caused by the movements of facial elements and muscles during the course of emotional expression. The facial elements, especially key elements, will constantly change their positions when subjects are expressing emotions. As a consequence, the same feature in different images usually has different positions. In some cases, the shape of the feature may also be distorted due to the subtle facial muscle movements. Therefore, for any feature representing a certain emotion, the geometric-based position and appearance-based shape normally changes from one image to another image in image databases, as well as in videos. This kind of movement features represents a rich pool of both static and dynamic characteristics of expressions, which playa critical role for FER. The vast majority of the past work on FER does not take the dynamics of facial expressions into account. Some efforts have been made on capturing and utilizing facial movement features, and almost all of them are static based. These efforts try to adopt either geometric features of the tracked facial points, or appearance difference between holistic facial regions in consequent frames or texture and motion changes in loca- facial regions. Although achieved promising results, these approaches often require accurate location and tracking of facial points, which remains problematic.

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LexisNexis Questions and Answers: Medical Law is designed to facilitate both continuous review and preparation for assignments and examinations. This book provides a clear and concise revision guide for each of the major topics covered in the typical health law course. It provides an understanding of medical law in each Australian jurisdiction and gives a clear and systematic approach to analysing and answering problem and essay questions. Each chapter commences with an identification of the key issues, including a summary of the relevant cases and legislation. Each question is followed by a suggested answer plan, a sample answer and comments on how the answer might be assessed by an examiner. The author also offers advice on common errors to avoid and practical hints and tips on how to achieve higher marks.

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In Christensen v Salter [2002] QDC 082 the District Court of Queensland considered some issues on the limitation period applying to claims arising out of a failed sterilisation procedure

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The morphology of plasmonic nano-assemblies has a direct influence on optical properties, such as localised surface plasmon resonance (LSPR) and surface enhanced Raman scattering (SERS) intensity. Assemblies with core-satellite morphologies are of particular interest, because this morphology has a high density of hot-spots, while constraining the overall size. Herein, a simple method is reported for the self-assembly of gold NPs nano-assemblies with a core-satellite morphology, which was mediated by hyperbranched polymer (HBP) linkers. The HBP linkers have repeat units that do not interact strongly with gold NPs, but have multiple end-groups that specifically interact with the gold NPs and act as anchoring points resulting in nano-assemblies with a large (~48 nm) core surrounded by smaller (~15 nm) satellites. It was possible to control the number of satellites in an assembly which allowed optical parameters such as SPR maxima and the SERS intensity to be tuned. These results were found to be consistent with finite-difference time domain (FDTD) simulations. Furthermore, the multiplexing of the nano-assemblies with a series of Raman tag molecules was demonstrated, without an observable signal arising from the HBP linker after tagging. Such plasmonic nano-assemblies could potentially serve as efficient SERS based diagnostics or biomedical imaging agents in nanomedicine.

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This study investigates if and why assessing relevance of clinical records for a clinical retrieval task is cognitively demanding. Previous research has highlighted the challenges and issues information retrieval systems are faced with when determining the relevance of documents in this domain, e.g., the vocabulary mismatch problem. Determining if this assessment imposes cognitive load on human assessors, and why this is the case, may shed lights on what are the (cognitive) processes that assessors use for determining document relevance (in this domain). High cognitive load may impair the ability of the user to make accurate relevance judgements and hence the design of IR mechanisms may need to take this into account in order to reduce the load.

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This article describes the first steps toward comprehensive characterization of molecular transport within scaffolds for tissue engineering. The scaffolds were fabricated using a novel melt electrospinning technique capable of constructing 3D lattices of layered polymer fibers with well - defined internal microarchitectures. The general morphology and structure order was then determined using T 2 - weighted magnetic resonance imaging and X - ray microcomputed tomography. Diffusion tensor microimaging was used to measure the time - dependent diffusivity and diffusion anisotropy within the scaffolds. The measured diffusion tensors were anisotropic and consistent with the cross - hatched geometry of the scaffolds: diffusion was least restricted in the direction perpendicular to the fiber layers. The results demonstrate that the cross - hatched scaffold structure preferentially promotes molecular transport vertically through the layers ( z - axis), with more restricted diffusion in the directions of the fiber layers ( x – y plane). Diffusivity in the x – y plane was observed to be invariant to the fiber thickness. The characteristic pore size of the fiber scaffolds can be probed by sampling the diffusion tensor at multiple diffusion times. Prospective application of diffusion tensor imaging for the real - time monitoring of tissue maturation and nutrient transport pathways within tissue engineering scaffolds is discussed.

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Electronic Medical Record (EMR) systems are being implemented increasingly worldwide. Saudi Arabia is one of the developing countries that commenced implementing such systems in 1988. Whilst EMR uptake has been low in Saudi Arabia until now, a number of hospitals have implemented EMR systems successfully. This paper analyses available studies (n = 28) in the literature regarding EMR implementation in Saudi Arabia to identify the progress of EMR implementation to date and to identify the facilitators and barriers to implementation.

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This study explored the stress and wellbeing of Emergency Medical Dispatchers (EMD) who remotely provide crisis intervention to medical emergencies through telehealth support. Semi-structured interviews with 16 EMDs were conducted and Interpretative Phenomenological Analysis was used to identify themes in the data. These results indicated that despite their physical distance from the crisis scene, EMDs can experience vicarious trauma through acute and cumulative exposure to traumatic incidents and their perceived lack of control which can expound feelings of helplessness. Three superordinate themes of operational stress and trauma, organisational stress, and posttraumatic growth were identified. Practical implications are suggested to enable emergency services organisations to counteract this job related stress and promote more positive mental health outcomes.

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Purpose: The cytomegalovirus (CMV) promoter is one of the most commonly used promoters for expression of transgenes in mammalian cells. The aim of our study was to evaluate the role of methylation and upregulation of the CMV promoter by irradiation and the chemotherapeutic agent cisplatin in vivo using non-invasive fluorescence in vivo imaging. Procedures: Murine fibrosarcoma LPB and mammary carcinoma TS/A cells were stably transfected with plasmids encoding CMV and p21 promoter-driven green fluorescent protein (GFP) gene. Solid TS/A tumors were induced by subcutaneous injection of fluorescent tumor cells, while leg muscles were transiently transfected with plasmid encoding GFP under the control of the CMV promoter. Cells, tumors, and legs were treated either by DNA methylation inhibitor 5-azacytidine, irradiation, or cisplatin. GFP expression was determined using a fluorescence microplate reader in vitro and by non-invasive fluorescence imaging in vivo. Results: Treatment of cells, tumors, and legs with 5-azacytidine (re)activated the CMV promoter. Furthermore, treatment with irradiation or cisplatin resulted in significant upregulation of GFP expression both in vitro and in vivo. Conclusions: Observed alterations in the activity of the CMV promoter limit the usefulness of this widely used promoter as a constitutive promoter. On the other hand, inducibility of CMV promoters can be beneficially used in gene therapy when combined with standard cancer treatment, such as radiotherapy and chemotherapy. © 2010 The Author(s).

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Normal asymmetric glow dc discharge in the thermal furnace converted into the efficient PECVD system was imaged to adjust the structure of the plasma column to the two possible localizations of the process zone. The visualization revealed the possibility to use short and long discharge configurations for the plasma-enabled growth and processing of various nanostructures in the modified setup. Images of the discharge in the two localizations are presented.

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Nanoparticle contrast agents offer the potential to significantly improve existing methods of cancer diagnosis and treatment. Advantages include biocompatibility, selective accumulation in tumor cells, and reduced toxicity. Considerable research is underway into the use of nanoparticles as enhancement agents for radiation therapy and photodynamic therapy, where they may be used to deliver treatment agents, produce localized enhancements in radiation dose and selectively target tumor cells for localized damage. This paper reviews the current status of nanoparticles for cancer treatment and presents preliminary results of a pilot study investigating titanium dioxide nanoparticles for dual-mode enhancement of computed tomography (CT) imaging and kilovoltage radiation therapy. Although titanium dioxide produced noticeable image contrast enhancement in the CT scans, more sensitive detectors are needed to determine whether the nanoparticles can also produce localized dose enhancement for targeted radiation therapy.

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Brain decoding of functional Magnetic Resonance Imaging data is a pattern analysis task that links brain activity patterns to the experimental conditions. Classifiers predict the neural states from the spatial and temporal pattern of brain activity extracted from multiple voxels in the functional images in a certain period of time. The prediction results offer insight into the nature of neural representations and cognitive mechanisms and the classification accuracy determines our confidence in understanding the relationship between brain activity and stimuli. In this paper, we compared the efficacy of three machine learning algorithms: neural network, support vector machines, and conditional random field to decode the visual stimuli or neural cognitive states from functional Magnetic Resonance data. Leave-one-out cross validation was performed to quantify the generalization accuracy of each algorithm on unseen data. The results indicated support vector machine and conditional random field have comparable performance and the potential of the latter is worthy of further investigation.

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Previous behavioral studies reported a robust effect of increased naming latencies when objects to be named were blocked within semantic category, compared to items blocked between category. This semantic context effect has been attributed to various mechanisms including inhibition or excitation of lexico-semantic representations and incremental learning of associations between semantic features and names, and is hypothesized to increase demands on verbal self-monitoring during speech production. Objects within categories also share many visual structural features, introducing a potential confound when interpreting the level at which the context effect might occur. Consistent with previous findings, we report a significant increase in response latencies when naming categorically related objects within blocks, an effect associated with increased perfusion fMRI signal bilaterally in the hippocampus and in the left middle to posterior superior temporal cortex. No perfusion changes were observed in the middle section of the left middle temporal cortex, a region associated with retrieval of lexical-semantic information in previous object naming studies. Although a manipulation of visual feature similarity did not influence naming latencies, we observed perfusion increases in the perirhinal cortex for naming objects with similar visual features that interacted with the semantic context in which objects were named. These results provide support for the view that the semantic context effect in object naming occurs due to an incremental learning mechanism, and involves increased demands on verbal self-monitoring.