1,205 research outputs found

    Three Dimensional Electrical Impedance Tomography

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    The electrical resistivity of mammalian tissues varies widely and is correlated with physiological function. Electrical impedance tomography (EIT) can be used to probe such variations in vivo, and offers a non-invasive means of imaging the internal conductivity distribution of the human body. But the computational complexity of EIT has severe practical limitations, and previous work has been restricted to considering image reconstruction as an essentially two-dimensional problem. This simplification can limit significantly the imaging capabilities of EIT, as the electric currents used to determine the conductivity variations will not in general be confined to a two-dimensional plane. A few studies have attempted three-dimensional EIT image reconstruction, but have not yet succeeded in generating images of a quality suitable for clinical applications. Here we report the development of a three-dimensional EIT system with greatly improved imaging capabilities, which combines our 64-electrode data-collection apparatus with customized matrix inversion techniques. Our results demonstrate the practical potential of EIT for clinical applications, such as lung or brain imaging and diagnostic screening

    Mom-I don't want to hear it: Brain response to maternal praise and criticism in adolescents with major depressive disorder

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    Recent research has implicated altered neural response to interpersonal feedback as an important factor in adolescent depression, with existing studies focusing on responses to feedback from virtual peers. We investigated whether depressed adolescents differed from healthy youth in neural response to social evaluative feedback from mothers. During neuroimaging, twenty adolescents in a current episode of major depressive disorder (MDD) and 28 healthy controls listened to previously recorded audio clips of their own mothers' praise, criticism and neutral comments. Whole-brain voxelwise analyses revealed that MDD youth, unlike controls, exhibited increased neural response to critical relative to neutral clips in the parahippocampal gyrus, an area involved in episodic memory encoding and retrieval. Depressed adolescents also showed a blunted response to maternal praise clips relative to neutral clips in the parahippocampal gyrus, as well as areas involved in reward and self-referential processing (i.e. Ventromedial prefrontal cortex, precuneus, and thalamus/caudate). Findings suggest that maternal criticism may be more strongly encoded or more strongly activated during memory retrieval related to previous autobiographical instances of negative feedback from mothers in depressed youth compared to healthy youth. Furthermore, depressed adolescents may fail to process the reward value and self-relevance of maternal praise

    Evidence That Qpx (Quahog Parasite Unknown) Is Not Present In Hatchery-Produced Hard Clam Seed

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    A protistan parasite known as QPX (Quahog Parasite Unknown) has been recently associated with disease and mortality of adult hard clams, Mercenaria mercenaria, from Canada to Virginia. There is concern that the organism may be transported in hatchery-reared seed. Tissue sections of 2,203 seed clams (\u3c1-20 mm) from 13 different hatcheries in six states, collected from 1995 to 1997 and examined by pathologists in three laboratories, failed to show QPX or QPX-like organisms. Further, QPX was not detected in a total of 756 hatchery-produced clams examined during their first year of field growout. From this, we conclude that hatchery-produced seed clams are an unlikely source of QPX organisms

    Investigating The Life Cycle Of Haplosporidium nelsoni (MSX)

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    Attempts to decipher the life cycle of Haplosporidium nelsoni began almost immediately after it was identified as the pathogen causing MSX disease in eastern oysters, Crassostrea virginica. But transmission experiments failed and the spore stage, characteristic of haplosporidans, was extremely rare. Researchers concluded that another host was involved: an intermediate host in which part of the life cycle was produced, or-if the oyster was an accidental host-an alternate host that produces infective elements. A later finding that spores were found more often in spat (\u3c 1 y old) than in adults revived the idea of direct transmission between oysters. The new findings and the availability of molecular diagnostics led us to revive life cycle investigations. Over several years, oyster spat were examined for spores and searched for H. nelsoni in potential non-oyster hosts using both histological and polymerase chain reaction (PCR) methodologies. Although spores occurred in a high proportion of spat with advanced infections, it was concluded that they were unlikely to be a principal source of infective elements because naive oysters used as sentinels to assess infection pressure became highly infected even after native oysters developed resistance, and infected spat could no longer be found. A histological survey of zooplankton and small bivalves in Delaware Bay found few recognizable parasites and nothing resembling a haplosporidan. A subsequent PCR study of water, sediment, and macro-invertebrates from Chesapeake, Delaware, and Oyster bays resulted in many positive samples, but in situ hybridization failed to identify any recognizable structures. PCR analysis of potential intermediate hosts for other molluscan pathogens has also resulted in many species yielding positive results but required in situ hybridization to verify infections. It is suggested that any future search for a nonoyster host of H. nelsoni be conducted in a relatively confined system and/or target specific phyla, strategies that have been successful in other life cycle studies. It is noted that candidate phyla could include those known to host haplosporidans and species whose abundance or distribution may have changed in concert with outbreaks of MSX disease in the northeastern United States in recent years

    Probabilistic Graphs for Sensor Data-driven Modelling of Power Systems at Scale

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    The growing complexity of the power grid, driven by increasing share of distributed energy resources and by massive deployment of intelligent internet-connected devices, requires new modelling tools for planning and operation. Physics-based state estimation models currently used for data filtering, prediction and anomaly detection are hard to maintain and adapt to the ever-changing complex dynamics of the power system. A data-driven approach based on probabilistic graphs is proposed, where custom non-linear, localised models of the joint density of subset of system variables can be combined to model arbitrarily large and complex systems. The graphical model allows to naturally embed domain knowledge in the form of variables dependency structure or local quantitative relationships. A specific instance where neural-network models are used to represent the local joint densities is proposed, although the methodology generalises to other model classes. Accuracy and scalability are evaluated on a large-scale data set representative of the European transmission grid

    The course of the superficial peroneal nerve in relation to the ankle position: anatomical study with ankle arthroscopic implications

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    Despite the fact that the superficial peroneal nerve is the only nerve in the human body that can be made visible; iatrogenic damage to this nerve is the most frequently reported complication in anterior ankle arthroscopy. One of the methods to visualize the nerve is combined ankle plantar flexion and inversion. In the majority of cases, the superficial peroneal nerve can be made visible. The portals for anterior ankle arthroscopy are however created with the ankle in the neutral or slightly dorsiflexed position and not in combined plantar flexion and inversion. The purpose of this study was to undertake an anatomical study to the course of the superficial peroneal nerve in different positions of the foot and ankle. We hypothesize that the anatomical localization of the superficial peroneal nerve changes with different foot and ankle positions. In ten fresh frozen ankle specimens, a window, only affecting the skin, was made at the level of the anterolateral portal for anterior ankle arthroscopy in order to directly visualize the superficial peroneal nerve, or if divided, its terminal branches. Nerve movement was assessed from combined 10° plantar flexion and inversion to 5° dorsiflexion, standardized by the Telos stress device. Also for the 4th toe flexion, flexion of all the toes and for skin tensioning possible nerve movement was determined. The mean superficial peroneal nerve movement was 2.4 mm to the lateral side when the ankle was moved from 10° plantar flexion and inversion to the neutral ankle position and 3.6 mm to the lateral side from 10° plantar flexion and inversion to 5° dorsiflexion. Both displacements were significant (P < 0.01). The nerve consistently moves lateral when the ankle is manoeuvred from combined plantar flexion and inversion to the neutral or dorsiflexed position. If visible, it is therefore advised to create the anterolateral portal medial from the preoperative marking, in order to prevent iatrogenic damage to the superficial peroneal nerve

    Strategies to self-manage side-effects of adjuvant endocrine therapy among breast cancer survivors: an umbrella review of empirical evidence and clinical guidelines

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    Purpose: Side-effects of adjuvant endocrine therapy (AET) are common in breast cancer survivors, and can affect adherence to treatment. We synthesised the evidence for strategies to self-manage these side-effects. Methods: We searched for systematic reviews and clinical guidelines on self-management strategies for AET side-effects (arthralgia, fatigue, hot flashes, gastrointestinal discomfort, nausea, vulvovaginal symptoms, and sleep disturbance). We searched oncology organisation’s websites and eight databases (Inception-November 2020). Screening, data extraction and quality assessment were completed independently in duplicate. PROSPERO: 2019CRD4201914001. Results: We identified 33 systematic reviews and 18 clinical guidelines. 21% of reviews were high quality, and the average quality score for guidelines was 44%. Evidence for most strategies was absent or weak. There was consensus from a low-quality review and multiple guidelines to recommend moisturisers, gels and lubricants for vulvovaginal symptoms. Evidence was weak for physical activity for self-managing most symptoms, although two high-quality reviews indicated yoga and aerobic exercise could reduce fatigue. Primary research was often biased by weak and underpowered study designs. Eleven reviews did not report information on adverse events. Conclusions: Most self-management strategies for breast cancer survivors experiencing side-effects from AET lack evidence. Primary research is needed using high-quality well-powered designs focusing on implementable strategies. Implications for Cancer Survivors: Patients and clinicians should be aware that although the risk of harm is low for these self-management strategies, the likelihood of benefit is often unclear. Women should consider moisturisers, gels or lubricants for self-managing vulvovaginal symptoms, and yoga or aerobic exercise for alleviating fatigue

    Medication administration errors for older people in long-term residential care

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    Background Older people in long-term residential care are at increased risk of medication errors. The purpose of this study was to evaluate a computerised barcode medication management system designed to improve drug administrations in residential and nursing homes, including comparison of error rates and staff awareness in both settings. Methods All medication administrations were recorded prospectively for 345 older residents in thirteen care homes during a 3-month period using the computerised system. Staff were surveyed to identify their awareness of administration errors prior to system introduction. Overall, 188,249 attempts to administer medication were analysed to determine the prevalence of potential medication administration errors (MAEs). Error classifications included attempts to administer medication at the wrong time, to the wrong person or discontinued medication. Analysis compared data at residential and nursing home level and care and nursing staff groups. Results Typically each resident was exposed to 206 medication administration episodes every month and received nine different drugs. Administration episodes were more numerous (p < 0.01) in nursing homes (226.7 per resident) than in residential homes (198.7). Prior to technology introduction, only 12% of staff administering drugs reported they were aware of administration errors being averted in their care home. Following technology introduction, 2,289 potential MAEs were recorded over three months. The most common MAE was attempting to give medication at the wrong time. On average each resident was exposed to 6.6 potential errors. In total, 90% of residents were exposed to at least one MAE with over half (52%) exposed to serious errors such as attempts to give medication to the wrong resident. MAEs rates were significantly lower (p < 0.01) in residential homes than nursing homes. The level of non-compliance with system alerts was low in both settings (0.075% of administrations) demonstrating virtually complete error avoidance. Conclusion Potentially inappropriate administration of medication is a serious problem in long-term residential care. A computerised barcode system can accurately and automatically detect inappropriate attempts to administer drugs to residents. This tool can reliably be used by care staff as well as nurses to improve quality of care and patient safety

    Anterior ankle arthroscopy, distraction or dorsiflexion?

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    Anterior ankle arthroscopy can basically be performed by two different methods; the dorsiflexion- or distraction method. The objective of this study was to determine the size of the anterior working area for both the dorsiflexion and distraction method. The anterior working area is anteriorly limited by the overlying anatomy which includes the neurovascular bundle. We hypothesize that in ankle dorsiflexion the anterior neurovascular bundle will move away anteriorly from the ankle joint, whereas in ankle distraction the anterior neurovascular bundle is pulled tight towards the joint, thereby decreasing the safe anterior working area. Six fresh frozen ankle specimens, amputated above the knee, were scanned with computed tomography. Prior to scanning the anterior tibial artery was injected with contrast fluid and subsequently each ankle was scanned both in ankle dorsiflexion and in distraction. A special device was developed to reproducibly obtain ankle dorsiflexion and distraction in the computed tomography scanner. The distance between the anterior border of the inferior tibial articular facet and the posterior border of the anterior tibial artery was measured. The median distance from the anterior border of the inferior tibial articular facet to the posterior border of the anterior tibial artery in ankle dorsiflexion and distraction was 0.9 cm (range 0.7–1.5) and 0.7 cm (range 0.5–0.8), respectively. The distance in ankle dorsiflexion significantly exceeded the distance in ankle distraction (P = 0.03). The current study shows a significantly increased distance between the anterior distal tibia and the overlying anterior neurovascular bundle with the ankle in a slightly dorsiflexed position as compared to the distracted ankle position. We thereby conclude that the distracted ankle position puts the neurovascular structures more at risk for iatrogenic damage when performing anterior ankle arthroscopy
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