3487 research outputs found
Sort by
Unraveling the Twist: Spatial Navigational Challenges in Cervical Dystonia
Get PDFBackground: Cervical dystonia (CD) is an intricate neurological condition with motor and nonmotor symptoms. These include disruptions in visual perception, self-orientation, visual working memory, and vestibular functions. However, the specific impact of CD on perceiving self-motion direction, especially with isolated visual or vestibular stimuli, remains largely unexplored. Objective: This study aimed to examine the effects of CD on linear motion perception, hypothesizing impaired heading discrimination in both vestibular and visual tasks, and that such deficits correlate with the disease severity. Methods: We employed a cutting-edge motion platform to precisely control whole-body linear motion. Through repeated two-alternative forced-choice tasks, we assessed vestibular heading direction discrimination. Participants observed dynamic star clouds in immersive virtual reality and indicated their perceived self-motion direction, evaluating visual heading direction discrimination. Sensitivity to direction variations and response accuracy errors were analyzed using robust Gaussian cumulative distribution psychometric functions. Results: Heading perception is impaired in individuals with CD, particularly evident in vestibular heading discrimination. CD severity correlated with elevated thresholds for both vestibular and visual heading discrimination. Surprisingly, lateralized CD did not introduce bias in either system, suggesting widespread disruption over localized effects. Conclusions: Contrary to previous beliefs, our findings challenge the idea that CD-related heading discrimination issues mainly arise from peripheral vestibular effects. Instead, abnormal proprioceptive input from dystonic neck muscles introduces noise into the central mechanism integrating visual, vestibular, and proprioceptive signals. These insights into spatial navigation deficits have implications for future CD research. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA
ZBTB16::RARA Variant Acute Promyelocytic Leukemia (vAPL) Treated with Gemtuzumab Ozogamicin (GO) with Unique Pathology and Genetic Findings
Get PDFSelf-Calibrated Through-Time Spiral Grappa for Real-Time, Free-Breathing Evaluation of Left Ventricular Function
No full textPurpose: Through-time spiral GRAPPA is a real-time imaging technique that enables ungated, free-breathing evaluation of the left ventricle. However, it requires a separate fully-sampled calibration scan to calculate GRAPPA weights. A self-calibrated through-time spiral GRAPPA method is proposed that uses a specially designed spiral trajectory with interleaved arm ordering such that consecutive undersampled frames can be merged to form calibration data, eliminating the separate fully-sampled acquisition. Theory and Methods: The proposed method considers the time needed to acquire data at all points in a GRAPPA calibration kernel when using interleaved arm ordering. Using this metric, simulations were performed to design a spiral trajectory for self-calibrated GRAPPA. Data were acquired in healthy volunteers using the proposed method and a comparison electrocardiogram-gated and breath-held cine scan. Left ventricular functional values and image quality are compared. Results: A 12-arm spiral trajectory was designed with a temporal resolution of 32.72 ms/cardiac phase with an acceleration factor of 3. Functional values calculated using the proposed method and the gold-standard method were not statistically significantly different (paired t-test, p \u3c 0.05). Image quality ratings were lower for the proposed method, with statistically significantly different ratings (Wilcoxon signed rank test, p \u3c 0.05) for two of five image quality aspects rated (level of artifact, blood-myocardium contrast). Conclusions: A self-calibrated through-time spiral GRAPPA reconstruction can enable ungated, free-breathing evaluation of the left ventricle in 71 s. Functional values are equivalent to a gold-standard cine technique, although some aspects of image quality may be inferior due to the real-time nature of the data collection
Examining How Congruence in and Satisfaction with Dyadic Care Type Appraisal Contribute to Quality of Life in Heart Failure Care Dyads
Get PDFAIMS: Given the complexity of heart failure (HF) management, persons with HF and their informal caregivers often engage in dyadic illness management. It is unknown how congruent appraisal of dyadic HF care type is associated with dyadic health. Our aim was to examine how congruence in and satisfaction with appraisal of dyadic HF care type contribute to quality of life (QOL) for dyads. METHODS AND RESULTS: This is a secondary analysis of cross-sectional data on 275 HF care dyads (patients 45.1% female, caregivers 70.5% female). Congruent appraisal and satisfaction were assessed using the Dyadic Symptom Management Type instrument. Quality of life was measured using the Short Form-12. Multilevel dyadic models were estimated to examine the contribution of congruence and satisfaction with dyadic care type to physical and mental QOL. Congruent appraisal of dyadic care type was positively associated with caregivers\u27 mental QOL (B = 2.69, P = 0.026). Satisfaction with dyadic care type was positively associated with physical and mental QOL for persons with HF (B = 1.58, P = 0.011 and B = 2.09, P = 0.002, respectively) and informal caregivers (B = 1.70, P = 0.004 and B = 2.90, P \u3c 0.001, respectively), while controlling for age, New York Heart Association class, daily hours spent together, relationship type, and congruence with dyadic care type. CONCLUSION: Satisfaction with dyadic care type appraisal was a stronger contributor to QOL for HF care dyads, compared with congruent appraisals. It is important to understand reasons for dissatisfaction within the dyad to assist dyad members in reaching shared appraisals while managing HF
The Mid‑Pleistocene Transition: A Delayed Response to an Increasing Positive Feedback?
Get PDFGlacial–interglacial cycles constitute large natural variations in Earth’s climate. The Mid-Pleistocene Transition (MPT) marks a shift of the dominant periodicity of these climate cycles from ∼40 to ∼100 kyr. Recently, it has been suggested that this shift resulted from a gradual increase in the internal period (or equivalently, a decrease in the natural frequency) of the system. As a result, the system would then have locked to ever higher multiples of the external forcing period. We find that the internal period is sensitive to the strength of positive feedbacks in the climate system. Using a carbon cycle model in which feedbacks between calcifier populations and ocean alkalinity mediate atmospheric CO2, we simulate stepwise periodicity changes similar to the MPT through such a mechanism. Due to the internal dynamics of the system, the periodicity shift occurs up to millions of years after the change in the feedback strength is imposed. This suggests that the cause for the MPT may have occurred a significant time before the observed periodicity shift
Investigation of a Cluster of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infections in a Hospital Administration Building
Get PDFObjective: To investigate a cluster of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in employees working on 1 floor of a hospital administration building. Methods: Contact tracing was performed to identify potential exposures and all employees were tested for SARS-CoV-2. Whole-genome sequencing was performed to determine the relatedness of SARS-CoV-2 samples from infected personnel and from control cases in the health-care system with coronavirus disease 2019 (COVID-19) during the same period. Carbon dioxide levels were measured during a workday to assess adequacy of ventilation; readings \u3e800 parts per million (ppm) were considered an indication of suboptimal ventilation. To assess the potential for airborne transmission, DNA-barcoded aerosols were released, and real-time polymerase chain reaction was used to quantify particles recovered from air samples in multiple locations. Results: Between December 22, 2020, and January 8, 2021, 17 coworkers tested positive for SARS-CoV-2, including 13 symptomatic and 4 asymptomatic individuals. Of the 5 cluster SARS-CoV-2 samples sequenced, 3 were genetically related, but these employees denied higher-risk contacts with one another. None of the sequences from the cluster were genetically related to the 17 control sequences of SARS-CoV-2. Carbon dioxide levels increased during a workday but never exceeded 800 ppm. DNA-barcoded aerosol particles were dispersed from the sites of release to locations throughout the floor; 20% of air samples had \u3e1 log10 particles. Conclusions: In a hospital administration building outbreak, sequencing of SARS-CoV-2 confirmed transmission among coworkers. Transmission occurred despite the absence of higher-risk exposures and in a setting with adequate ventilation based on monitoring of carbon dioxide levels
Use of an Invertebrate Animal Model (Aplysia Californica) to Develop Novel Neural Interfaces for Neuromodulation
No full textNew tools for monitoring and manipulating neural activity have been developed with steadily improving functionality, specificity, and reliability, which are critical both for mapping neural circuits and treating neurological diseases. This review focuses on the use of an invertebrate animal, the marine mollusk Aplysia californica, in the development of novel neurotechniques. We review the basic physiological properties of Aplysia neurons and discuss the specific aspects that make it advantageous for developing novel neural interfaces: First, Aplysia nerves consist only of unmyelinated axons with various diameters, providing a particularly useful model of the unmyelinated C fibers in vertebrates that are known to carry important sensory information, including those that signal pain. Second, Aplysia’s neural tissues can last for a long period in an ex vivo experimental setup. This allows comprehensive tests such as the exploration of parameter space on the same nerve to avoid variability between animals and minimize animal use. Third, nerves in large Aplysia can be many centimeters in length, making it possible to easily discriminate axons with different diameters based on their conduction velocities. Aplysia nerves are a particularly good approximation of the unmyelinated C fibers, which are hard to stimulate, record, and differentiate from other nerve fibers in vertebrate animal models using epineural electrodes. Fourth, neurons in Aplysia are large, uniquely identifiable, and electrically compact. For decades, researchers have used Aplysia for the development of many novel neurotechnologies. Examples include high-frequency alternating current (HFAC), focused ultrasound (FUS), optical neural stimulation, recording, and inhibition, microelectrode arrays, diamond electrodes, carbon fiber microelectrodes, microscopic magnetic stimulation and magnetic resonance electrical impedance tomography (MREIT). We also review a specific example that illustrates the power of Aplysia for accelerating technology development: selective infrared neural inhibition of small-diameter unmyelinated axons, which may lead to a translationally useful treatment in the future. Generally, Aplysia is suitable for testing modalities whose mechanism involves basic biophysics that is likely to be similar across species. As a tractable experimental system, Aplysia californica can help the rapid development of novel neuromodulation technologies
Environmental Effects of Stratospheric Ozone Depletion, UV Radiation, and Interactions with Climate Change: UNEP Environmental Effects Assessment Panel, Update 2021
Get PDFThe Environmental Effects Assessment Panel of the Montreal Protocol under the United Nations Environment Programme evaluates effects on the environment and human health that arise from changes in the stratospheric ozone layer and concomitant variations in ultraviolet (UV) radiation at the Earth’s surface. The current update is based on scientific advances that have accumulated since our last assessment (Photochem and Photobiol Sci 20(1):1–67, 2021). We also discuss how climate change affects stratospheric ozone depletion and ultraviolet radiation, and how stratospheric ozone depletion affects climate change. The resulting interlinking effects of stratospheric ozone depletion, UV radiation, and climate change are assessed in terms of air quality, carbon sinks, ecosystems, human health, and natural and synthetic materials. We further highlight potential impacts on the biosphere from extreme climate events that are occurring with increasing frequency as a consequence of climate change. These and other interactive effects are examined with respect to the benefits that the Montreal Protocol and its Amendments are providing to life on Earth by controlling the production of various substances that contribute to both stratospheric ozone depletion and climate change
The Nested Embryonic Dorsal Domains of BMP-Target Genes are Not Scaled to Size During the Evolution of Drosophila Species
No full textEgg size is a fast-evolving trait among Drosophilids expected to change the spatial distribution of morphogens that pattern the embryonic axes. Here we asked whether the patterning of the dorsal region of the embryo by the Decapentaplegic/Bone Morphogenetic Protein-4 (DPP/BMP-4) gradient is scaled among Drosophila species with different egg sizes. This region specifies the extra-embryonic tissue amnioserosa and the ectoderm. We find that the entire dorsal region scales with embryo size, but the gene expression patterns regulated by DPP are not proportional, suggesting that the DPP gradient is differentially scaled during evolution. To further test whether the DPP gradient can scale or not in Drosophila melanogaster, we created embryos with expanded dorsal regions that mimic changes in scale seen in other species and measured the resulting domains of DPP-target genes. We find that the proportions of these domains are not maintained, suggesting that the DPP gradient is unable to scale in the embryo. These and previous findings suggest that the embryonic dorso-ventral patterning lack scaling in the ventral and dorsal sides but is robust in the lateral region where the neuroectoderm is specified and two opposing gradients, Dorsal/NFkappa-B and DPP, intersect. We propose that the lack of scaling of the DPP gradient may contribute to changes in the size of the amnioserosa and the numbers of ectodermal cells with specific cortical tensions, which are expected to generate distinct mechanical forces for gastrulating embryos of different sizes
AI-Informed Approaches to Keyword Generation, Text Summarization, and Document Clustering for Improved Resource Discovery
Get PDFAcademic and cultural institutions are grappling with problems of how to organize, label, and search disparate bodies of texts. As aggregators, preservers, and disseminators of substantial repositories of digital texts, research libraries are naturally situated at the heart of these problems. This chapter explores how unsupervised machine learning may be used to capture and simplify the complexity and nuances of text. Traditional approaches to improving discoverability and accessibility of text through metadata and controlled vocabularies have time-tested strengths. As the volume of digital data explodes, the obstacles and limitations of traditional approaches become more pronounced, and machine learning “show(s) the potential to create efficiencies that smooth the path to access, enhancing description and expanding forms of discovery along the way.”1 In light of the need for new approaches to metadata generation to facilitate discovery, the authors look at Doc2Vec and topic modelling with Latent Dirichlet Allocation (LDA) to explore their utility as assistive tools for authors, librarians, and readers. The authors apply the two approaches to a corpus of electronic theses and dissertations (ETDs) completed at Ohio universities and colleges
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇