323 research outputs found

    Evidence for Magnetic Field Induced Changes of the Phase of Tunneling States: Spontaneous Echoes in (KBr)1x_{1-x}(KCN)x_x in Magnetic Fields

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    Recently, it has been discovered that in contrast to expectations the low-temperature dielectric properties of some multi-component glasses depend strongly on magnetic fields. In particular, the low-frequency dielectric susceptibility and the amplitude of coherent polarization echoes show striking non-monotonic magnetic field dependencies. The low-temperature dielectric response of these materials is governed by atomic tunneling systems. We now have investigated the coherent properties of tunneling states in a crystalline host in magnetic fields up to 230 mT. Two-pulse echo experiments have been performed on a KBr crystal containing about 7.5% CN^-. Like in glasses, but perhaps even more surprising in the case of a crystalline system, we observe a very strong magnetic field dependence of the echo amplitude. Moreover, for the first time we have direct evidence that magnetic fields change the phase of coherent tunneling systems in a well-defined way. We present the data and discuss the possible origin of this intriguing effect.Comment: 4 pages, 3 figures, submitted to PR

    A Systematic Review of Extended Reality (XR) for Understanding and Augmenting Vision Loss

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    Over the past decade, extended reality (XR) has emerged as an assistive technology not only to augment residual vision of people losing their sight but also to study the rudimentary vision restored to blind people by a visual neuroprosthesis. To make the best use of these emerging technologies, it is valuable and timely to understand the state of this research and identify any shortcomings that are present. Here we present a systematic literature review of 227 publications from 106 different venues assessing the potential of XR technology to further visual accessibility. In contrast to other reviews, we sample studies from multiple scientific disciplines, focus on augmentation of a person's residual vision, and require studies to feature a quantitative evaluation with appropriate end users. We summarize prominent findings from different XR research areas, show how the landscape has changed over the last decade, and identify scientific gaps in the literature. Specifically, we highlight the need for real-world validation, the broadening of end-user participation, and a more nuanced understanding of the suitability and usability of different XR-based accessibility aids. By broadening end-user participation to early stages of the design process and shifting the focus from behavioral performance to qualitative assessments of usability, future research has the potential to develop XR technologies that may not only allow for studying vision loss, but also enable novel visual accessibility aids with the potential to impact the lives of millions of people living with vision loss

    THE PREVALENCE OF PALPABLE FINGER JOINT NODULES IN DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH). A CONTROLLED STUDY

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    The presence of clinically palpable finger joint nodules a(Heberden's and Bouchard's nodes) was documented in 123 consecutive cases with diffuse idiopathic skeletal hyperostosis (DISH) of the thoracic spine and 191 matched DISH negative controls. The prevalence of palpable finger joint nodules was almost twice as frequent in cases with spinal DISH compared to controls (46% versus 31%, X2 = 7.67, P<0.01; multivariate adjusted odds ratio OR = 1.84; 95% CI: 1.14-2.98). This increase was most marked at the proximal interphalangeal joint, in males and in patients up to the age of 65 years. In addition and independent of other variables such as hyperostotic features, age and sex, the prevalence of palpable finger joint nodules was about twice as high in probands with a history of physically heavy work compared to those without (43% ver sus 26%, X = 9.18, P<0.005; multivariate adjusted odds ratio OR = 2.10; 95% CI: 1.26-3.52). From these results we con clude that DISH should be considered as an independent risk factor in the development of finger joint nodule

    SEVERE OSTEOPOROSIS DUE TO SYSTEMIC MAST CELL DISEASE: SUCCESSFUL TREATMENT WITH INTERFERON ALPHA-2B

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    We describe a 33-yr-old man suffering from severe vertebral osteoporosis and urticaria pigmentosa due to systemic mast cell disease (SMCD). Because i.v. clodronate therapy could not prevent further vertebral fractures, an additional treatment with interferon alpha-2b was initiated. During 24 months of treatment, our patient had no further pain episodes, no new vertebral fractures were discovered, trabecular bone mineral density (BMD) increased significantly and urticarial symptoms improved. Nevertheless, the extent of skin lesions remained unchanged. On histological examination, a remarkable decrease of mast cells was observed in the bone marrow, but not in the skin. Five months after discontinuation of interferon alpha-2b, trabecular BMD decreased and urticarial symptoms deteriorated. These findings illustrate a beneficial effect of interferon alpha-2b on SMCD-induced osteoporosis as well as urticarial symptoms, and raise the question whether this treatment may have a diverse impact on mast cell populations in different tissue

    Bio-Inspired Multi-Layer Spiking Neural Network Extracts Discriminative Features from Speech Signals

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    Spiking neural networks (SNNs) enable power-efficient implementations due to their sparse, spike-based coding scheme. This paper develops a bio-inspired SNN that uses unsupervised learning to extract discriminative features from speech signals, which can subsequently be used in a classifier. The architecture consists of a spiking convolutional/pooling layer followed by a fully connected spiking layer for feature discovery. The convolutional layer of leaky, integrate-and-fire (LIF) neurons represents primary acoustic features. The fully connected layer is equipped with a probabilistic spike-timing-dependent plasticity learning rule. This layer represents the discriminative features through probabilistic, LIF neurons. To assess the discriminative power of the learned features, they are used in a hidden Markov model (HMM) for spoken digit recognition. The experimental results show performance above 96% that compares favorably with popular statistical feature extraction methods. Our results provide a novel demonstration of unsupervised feature acquisition in an SNN

    DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH) OF THE SHOULDER: A CAUSE OF SHOULDER PAIN?

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    Shoulder pain is a common complaint and shoulder hyperostosis a frequent radiological condition. However, little is known about the association between the clinical and radiological findings. To evaluate the clinical relevance of shoulder hyperostosis we performed a controlled, blind study of 99 hospitalized probands with and without thoracospinal hyperostosis on lateral chest X-rays. The study included grading of the shoulder hyperostosis on the basis of three bilateral standard radiographs, assessing shoulder pain in a standardized way by an interviewer and recording extraskeletal causes of shoulder pain. The prevalence of shoulder hyperostosis was doubled in probands with thoracospinal hyperostosis compared to controls (X2= 5.90, F>0.025, n = 99). Shoulder hyperostosis, irrespective of thoracospinal hyperostosis, predisposed to shoulder pain (40% versus 18%, x2 = 4.06, F>0.05, n = 74). Shoulder hyperostosis in combination with thoracospinal hyperostosis (shoulder DISH) predisposed to shoulder pain to an even greater extent (46% versus 12%, x2 = 6.64, P>0.01, n = 47). We conclude that shoulder hyperostosis is a radiological finding of potential clinical relevanc

    Maternal opioids age-dependently impair neonatal respiratory control networks

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    19 pagesInfants exposed to opioids in utero are an increasing clinical population and these infants are often diagnosed with Neonatal Abstinence Syndrome (NAS). Infants with NAS have diverse negative health consequences, including respiratory distress. However, many factors contribute to NAS, confounding the ability to understand how maternal opioids directly impact the neonatal respiratory system. Breathing is controlled centrally by respiratory networks in the brainstem and spinal cord, but the impact of maternal opioids on developing perinatal respiratory networks has not been studied. Using progressively more isolated respiratory network circuitry, we tested the hypothesis that maternal opioids directly impair neonatal central respiratory control networks. Fictive respiratory-related motor activity from isolated central respiratory networks was age-dependently impaired in neonates after maternal opioids within more complete respiratory networks (brainstem and spinal cords), but unaffected in more isolated networks (medullary slices containing the preBötzinger Complex). These deficits were due, in part, to lingering opioids within neonatal respiratory control networks immediately after birth and involved lasting impairments to respiratory pattern. Since opioids are routinely given to infants with NAS to curb withdrawal symptoms and our previous work demonstrated acute blunting of opioid-induced respiratory depression in neonatal breathing, we further tested the responses of isolated networks to exogenous opioids. Isolated respiratory control networks also demonstrated age-dependent blunted responses to exogenous opioids that correlated with changes in opioid receptor expression within a primary respiratory rhythm generating region, the preBötzinger Complex. Thus, maternal opioids agedependently impair neonatal central respiratory control and responses to exogenous opioids, suggesting central respiratory impairments contribute to neonatal breathing destabilization after maternal opioids and likely contribute to respiratory distress in infants with NAS. These studies represent a significant advancement of our understanding of the complex effects of maternal opioids, even late in gestation, contributing to neonatal breathing deficits, necessary first steps in developing novel therapeutics to support breathing in infants with NAS

    Atrial and placental melanoma metastasis: a case report and literature review

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    Malignant melanoma can metastasize to virtually any organ of the body. The aggressiveness is determined by the primary site, depth of dermal invasion, presence or absence of ulceration, lymphovascular infiltration and regional lymph node involvement. We report a case of a pregnant woman with a previous history of stage 3 melanoma who presented with cardiac metastasis and placental melanoma infiltration. A review of literature on cardiac and placental involvement of melanoma is also provided

    Migraine aura-like symptoms at onset of stroke and stroke-like symptoms in migraine with aura.

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    Background and objectives In general, suddenly occurring neurological deficits, i.e., negative neurological symptoms, are considered symptoms of focal cerebral ischemia, while positive irritative symptoms with gradual onset are viewed as the characteristics of migraine aura. Nevertheless, cortical spreading depolarization, the pathophysiological basis of migraine aura, has also been observed in acute ischemic stroke. The aim of our study was to determine the frequency of migraine aura-like symptoms at ischemic stroke onset and stroke-like symptoms in migraine with aura. Methods We interviewed 350 consecutive patients with ischemic stroke and 343 with migraine with aura using a structured questionnaire. Stroke diagnosis was confirmed by imaging, and migraine with aura was diagnosed according to the current criteria of the International Headache Society. Patients with wake-up strokes or severe cognitive deficits that precluded a useful interview were excluded from the study. Results Seventy-eight patients with stroke (22.3%) reported visual symptoms, 145 (41.4%) sensory symptoms, 197 (56.3%) a paresis, and 201 patients (57.4%) more than one symptom, compared to 326 migraine patients with aura (95%) with visual symptoms (P < 0.001), 175 (51%) with sensory symptoms (p = 0.011), 50 (14.6%) with paresis (P < 0.001), and 211 (61.5%) with more than one symptom (p = 0.27). Among patients with stroke, migraine-like symptoms were frequent: 36 patients (46.2%) with visual disturbance and 78 (53.8%) with sensory symptoms experienced irritative sensations. Paresis-onset in stroke lasted longer than 5 min in 43 patients (21.8%). Spreading of sensory and motor symptoms occurred in 37 (25.5%) and 37 (18.8%) patients, respectively. Stroke-like negative symptoms in migraine with aura occurred in 39 patients (12%) with visual symptoms, in 55 (31.4%) with sensory symptoms, and paresis appeared suddenly in 14 patients (28%). More than one symptom in succession occurred in 117 patients with stroke (58.2%) and in 201 migraine with aura patients (95.3%; P < 0.001). Conclusion Many patients with stroke experience migraine-like symptoms at stroke onset, and many migraine with aura patients have stroke-like symptoms. Though overall the symptom frequencies of the two groups are significantly different, clarifying the differential diagnosis in an individual patient requires additional history elements, physical findings, or results of ancillary investigations
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