107 research outputs found
252. Prediction of subject-specific SAR distribution in MSK MR exam at 7 T
Purpose
we predict SAR during MRI exam using a 7 T 1H 298 MHz eight-channel degenerate birdcage coil1 combining SAR simulations with subject-specific measured (RF) maps.
Materials and Methods
We simulated the coil1 in CST MW Suite, loaded by a model of human knee (Fig. 1, top). was calculated in an axial slice crossing the patella. The maximum local SAR for an Axial “Zero” Time-of-Echo (ZTE) sequence “SILENT”2 was calculated.
We acquired maps of an adult (female) knee with a Bloch-Siegert sequence on 7 axial slices, centered on the same slice of the simulation, on a GE MR950 7T human system. For each slice a coefficient C, proportional to avg, was used to scale the SAR simulated3.
Results
Fig. 1 shows: bottom left, simulated magnitude; bottom center, local SAR for an input of 1 W per channel; bottom right, simulated magnitude for a FA = 90° (length = 3.2 ms) sinc-pulse in the slice previously chosen.
Fig. 2 shows the subject-specific measured for a FA = 90° sinc-pulse. The predicted SAR obtained with scaled maps are 0.50 W/kg (global) and 3.68 W/kg (maximum).
Conclusions
we obtained a good agreement between simulated and measured in vivo maps, and we were able to calculate the distribution of SAR exposure, a safety MRI parameter not available in current exams, where only global SAR is provided, combining simulations and subject-specific measurements. Limits on global and local SAR (20 W/kg) were met for this sequence [1], [2], [3]
Enhancing home health mobile phone app usability through general smartphone training: usability and learnability case study.
peer-reviewedEach year, millions of older adults fall, with more than 1 out of 4 older people experiencing a fall annually, thereby causing a major social and economic impact. Falling once doubles oneâ s chances of falling again, making fall prediction an important aspect of preventative strategies. In this study, 22 older adults aged between 65 and 85 years were trained in the use of a smartphone-based fall prediction system. The system is designed to continuously assess fall risk by measuring various gait and balance parameters using a smart insole and smartphone, and is also designed to detect falls. The use case of the fall prediction system in question required the users to interact with the smartphone via an app for device syncing, data uploads, and checking system status.
The objective of this study was to observe the effect that basic smartphone training could have on the user experience of a group that is not technically proficient with smartphones when using a new connected health system. It was expected that even short rudimentary training could have a large effect on user experience and therefore increase the chances of the group accepting the new technology.
All participants received training on how to use the system smartphone app; half of the participants (training group) also received extra training on how to use basic functions of the smartphone, such as making calls and sending text messages, whereas the other half did not receive this extra training (no extra training group). Comparison of training group and no extra training group was carried out using metrics such as satisfaction rating, time taken to complete tasks, cues required to complete tasks, and errors made during tasks.
The training group fared better in the first 3 days of using the system. There were significant recorded differences in number of cues required and errors committed between the two groups. By the fourth and fifth day of use, both groups were performing at the same level when using the system.
Supplementary basic smartphone training may be critical in trials where a smartphone appâ based system for health intervention purposes is being introduced to a population that is not proficient with technology. This training could prevent early technology rejection and increase the engagement of older participants and their overall user experience with the system.PUBLISHEDpeer-reviewe
Pigmentary retinopathy can indicate the presence of pathogenic LAMP2 variants even in somatic mosaic carriers with no additional signs of Danon disease
PURPOSE: Danon disease (DD) is a rare X-linked disorder caused by pathogenic variants in LAMP2. DD primarily manifests as a severe cardiomyopathy. An early diagnosis is crucial for patient survival. The aim of the study was to determine the usefulness of ocular examination for identification of DD. METHODS: Detailed ocular examination in 10 patients with DD (3 males, 7 females) and a 45-year-old asymptomatic female somatic mosaic carrier of a LAMP2 disease-causing variant. RESULTS: All patients with manifest cardiomyopathy had pigmentary retinopathy with altered autofluorescence and diffuse visual field loss. Best corrected visual acuity (BCVA) was decreased (<0.63) in 8 (40%) out of 20 eyes. The severity of retinal pathology increased with age, resulting in marked cone-rod involvement overtime. Spectral-domain optical coherence tomography in younger patients revealed focal loss of photoreceptors, disruption and deposition at the retinal pigment epithelium/Bruch's membrane layer (corresponding to areas of marked increased autofluorescence), and hyperreflective foci in the outer nuclear layer. Cystoid macular oedema was seen in one eye. In the asymptomatic female with somatic mosaicism, the BCVA was 1.0 bilaterally. An abnormal autofluorescence pattern in the left eye was present; while full-field electroretinography was normal. CONCLUSIONS: Detailed ocular examination may represent a sensitive and quick screening tool for the identification of carriers of LAMP2 pathogenic variants, even in somatic mosaicism. Hence, further investigation should be undertaken in all patients with pigmentary retinal dystrophy as it may be a sign of a life-threatening disease
Zoonotic dermatophytoses: Clinical manifestation, diagnosis, etiology, treatment, epidemiological situation in the czech republic
Silicon Substrate Strained and Structured via Cavitation Effect for Photovoltaic and Biomedical Application
State of the world’s plants and fungi 2020
Kew’s State of the World’s Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kew’s State of the World’s Plants and Fungi sets an important international standard from which we can annually track trends in the global status of plant and fungal diversity
Opinions on computers, and efficacy of a computer-based learning: A pilot study
It is commonly believed that positive opinions of students and teachers on the possibilities entailed by computer use would increase the efficacy of computer-based educational processes. In turn, this amounts to postulate a relationship between measures of such opinions and well-defined patterns of interaction with computer-based educational tools. In this regard, this paper reports on an investigation performed in a primary school, designed to test whether expectations and opinions on computers, both of students and teachers, detected through suitable questionnaires, might be related to the effectiveness of computer use within a particular educational context. Our findings, contrarily to what expected, do not appear to support the hypothesis that a positive opinion on computers can lead per se to higher learning efficacy in a computer-based educational environment, as compared with a traditional educational setting
Un esempio di rappresentazione cognitiva dello strumento tecnologico nel sistema scolastico italiano
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