2,091 research outputs found

    Timbral and spatial fidelity improvement in ambisonics

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    © 2015 Elsevier Ltd. All rights reserved. Ambisonics renders a sound field through different kinds of loudspeaker layouts, which leads to different listening perceptions. While some loudspeaker arrays reinforce timbral fidelity, some improve localization accuracy. A split-band decoding is proposed that aims to select and then mix the better reconstructed frequency components from different loudspeaker arrays, thereby achieving the improved quality. The spectral reconstruction errors caused by truncation, comb filtering, and low-pass filtering are illustrated. The proposed solution is described, along with the experimental results from the listening tests. The split-band decoding method is especially suitable for binaural rendering and can also be applied to conventional loudspeaker arrays

    Giant schwannoma of thoracic vertebra: A case report

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    BACKGROUND,It is relatively rare for schwannomas to invade bone, but it is very rare for a large,mass to form concurrently in the paravertebral region. Surgical resection is the,only effective treatment. Because of the extensive tumor involvement and the,many important surrounding structures, the tumor needs to be fully exposed.,Most of the tumors are completely removed by posterior combined open-heart,surgery to relieve spinal cord compression, restore the stability of the spine and,maximize the recovery of nerve and spinal cord function. The main objective of,this article is to present a schwannoma that had invaded the T5 and T6 vertebral,bodies and formed a large paravertebral mass with simultaneous invasion of the,spinal canal and compression of the spinal cord.,CASE SUMMARY,A 40-year-old female suffered from intermittent chest and back pain for 8 years.,Computed tomography and magnetic resonance imaging scans showed a,paravertebral tumor of approximately 86 mm × 109 mm × 116 mm, where the,adjacent T5 and T6 vertebral bodies were invaded by the tumor, the right intervertebral,foramen was enlarged, and the tumor had invaded the spinal canal to,compress the thoracic medulla. The preoperative puncture biopsy diagnosed a,benign schwannoma. Complete resection of the tumor was achieved by a two-step,operation. In the first step, the thoracic surgeon adopted a lateral approach to,separate the thoracic tumor from the lung. In the second step, a spine surgeon,performed a posterior midline approach to dissect the tumor from the vertebral,junction through removal of the tumor from the posterior side and further,resection of the entire T5 and T6 vertebral bodies. The large bone defect was,reconstructed with titanium mesh, and the posterior root arch was nail-fixed. Due,to the large amount of intraoperative bleeding, we performed tumor angioembolization,before surgery to reduce and avoid large intraoperative bleeding. The,postoperative diagnosis of benign schwannoma was confirmed by histochemical,examination. There was no sign of tumor recurrence or spinal instability during,the 2-year follow-up.,CONCLUSION,Giant schwannoma is uncommon. In this case, a complete surgical resection of a,giant thoracic nerve sheath tumor that invaded part of the vertebral body and,compressed the spinal cord was safe and effective

    On the monotone stability approach to BSDEs with jumps: Extensions, concrete criteria and examples

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    We show a concise extension of the monotone stability approach to backward stochastic differential equations (BSDEs) that are jointly driven by a Brownian motion and a random measure for jumps, which could be of infinite activity with a non-deterministic and time inhomogeneous compensator. The BSDE generator function can be non convex and needs not to satisfy global Lipschitz conditions in the jump integrand. We contribute concrete criteria, that are easy to verify, for results on existence and uniqueness of bounded solutions to BSDEs with jumps, and on comparison and a-priori LL^{\infty}-bounds. Several examples and counter examples are discussed to shed light on the scope and applicability of different assumptions, and we provide an overview of major applications in finance and optimal control.Comment: 28 pages. Added DOI https://link.springer.com/chapter/10.1007%2F978-3-030-22285-7_1 for final publication, corrected typo (missing gamma) in example 4.1

    Ptch2/Gas1 and Ptch1/Boc differentially regulate Hedgehog signalling in murine primordial germ cell migration.

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    Gas1 and Boc/Cdon act as co-receptors in the vertebrate Hedgehog signalling pathway, but the nature of their interaction with the primary Ptch1/2 receptors remains unclear. Here we demonstrate, using primordial germ cell migration in mouse as a developmental model, that specific hetero-complexes of Ptch2/Gas1 and Ptch1/Boc mediate the process of Smo de-repression with different kinetics, through distinct modes of Hedgehog ligand reception. Moreover, Ptch2-mediated Hedgehog signalling induces the phosphorylation of Creb and Src proteins in parallel to Gli induction, identifying a previously unknown Ptch2-specific signal pathway. We propose that although Ptch1 and Ptch2 functionally overlap in the sequestration of Smo, the spatiotemporal expression of Boc and Gas1 may determine the outcome of Hedgehog signalling through compartmentalisation and modulation of Smo-downstream signalling. Our study identifies the existence of a divergent Hedgehog signal pathway mediated by Ptch2 and provides a mechanism for differential interpretation of Hedgehog signalling in the germ cell niche

    Validation of the psychometric properties of the health-promoting lifestyle profile in a sample of Taiwanese women

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    PURPOSE: To examine the preliminary psychometric properties of the Chinese health-promoting lifestyle profile II (HPLP II) among Taiwanese women. METHODS: We conducted a secondary analysis of cross-sectional data from 137 middle-aged women in southern Taiwan. HPLP II reliability was estimated with Cronbach's alpha coefficient, and concurrent validity was estimated with Pearson's correlation between the HPLP II, the World Health Organization's abbreviated Quality of Life assessment (WHOQOL-BREF), perceived health, and demographic variables. Confirmatory factor analysis (CFA) evaluated construct validity. RESULTS: Initial CFA using a six-factor measurement model aligned with the original HPLP II, excepting the factor loading of one subsequently excluded item. CFA of the revised 51-item HPLP II yielded a good estimate of fit. Correlations between the revised instrument and the six subscales were acceptable >0.7. The Cronbach's alpha coefficient surpassed 0.7 for the revised instrument and six subscales ranged from 0.71 to 0.91. The relationships between the 51-item instrument, perceived health, WHOQOL-BREF domain scores, and demographic variables were also significantly positive. CONCLUSIONS: The revised HPLP II scale is appropriate to measure the health-promoting lifestyles of Taiwanese women.published_or_final_versionSpringer Open Choice, 21 Feb 201

    Modification of Modeling Method of Toxic Dystrophy of Liver in Rats

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    The liver is the largest digestive gland that plays an important role in providing homeostasis of the internal environment of the body and in the development of adaptive reactions, which is due to its participation in many metabolic processes, anatomical, and functional connections with other organs and systems of the body. Recently, the risk of developing hepatopathy is increasingly associated with irrational pharmacotherapy of the underlying disease

    Synchrotron radiography of Richtmyer–Meshkov instability driven by exploding wire arrays

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    We present a new technique for the investigation of shock-driven hydrodynamic phenomena in gases, liquids, and solids in arbitrary geometries. The technique consists of a pulsed power-driven resistive wire array explosion in combination with multi-MHz synchrotron radiography. Compared to commonly used techniques, it offers multiple advantages: (1) the shockwave geometry can be shaped to the requirements of the experiment, (2) the pressure (P > 300 MPa) generated by the exploding wires enables the use of liquid and solid hydrodynamic targets with well-characterized initial conditions (ICs), (3) the multi-MHz radiography enables data acquisition to occur within a single experiment, eliminating uncertainties regarding repeatability of the ICs and subsequent dynamics, and (4) the radiographic measurements enable estimation of compression ratios from the x-ray attenuation. In addition, the use of a synchrotron x-ray source allows the hydrodynamic samples to be volumetrically characterized at a high spatial resolution with synchrotron-based microtomography. This experimental technique is demonstrated by performing a planar Richtmyer–Meshkov instability (RMI) experiment on an aerogel–water interface characterized by Atwood number A 0 ∼ − 0.8 and Mach number M ∼ 1.5. The qualitative and quantitative features of the experiment are discussed, including the energy deposition into the exploding wires, shockwave generation, compression of the interface, startup phase of the instability, and asymptotic growth consistent with Richtmyer's impulsive theory. Additional effects unique to liquids and solids—such as cavitation bubbles caused by rarefaction flows or initial jetting due to small perturbations—are observed. It is also demonstrated that the technique is not shape dependent by driving a cylindrically convergent RMI experiment

    Bcl-2 protein family: Implications in vascular apoptosis and atherosclerosis

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    Apoptosis has been recognized as a central component in the pathogenesis of atherosclerosis, in addition to the other human pathologies such as cancer and diabetes. The pathophysiology of atherosclerosis is complex, involving both apoptosis and proliferation at different phases of its progression. Oxidative modification of lipids and inflammation differentially regulate the apoptotic and proliferative responses of vascular cells during progression of the atherosclerotic lesion. Bcl-2 proteins act as the major regulators of extrinsic and intrinsic apoptosis signalling pathways and more recently it has become evident that they mediate the apoptotic response of vascular cells in response to oxidation and inflammation either in a provocative or an inhibitory mode of action. Here we address Bcl-2 proteins as major therapeutic targets for the treatment of atherosclerosis and underscore the need for the novel preventive and therapeutic interventions against atherosclerosis, which should be designed in the light of molecular mechanisms regulating apoptosis of vascular cells in atherosclerotic lesions
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