304 research outputs found
Electronic properties of very thin native SiO2/a-Si:H interfaces and their comparison with those prepared by both dielectric barrier discharge oxidation at atmospheric pressure and by chemical oxidation
The contribution deals with electronic properties of thin oxide/amorphous hydrogenated silicon (a-Si:H) measured by capacitance-voltage (C-V) and charge version of deep level transient spectroscopy (Q-DLTS). The interest was focused on the studies of the interface properties of very thin dielectrics formed by dielectric barrier discharge (DBD) or natively on the a-Si:H layer. These properties were compared with those of oxide layers prepared by chemical oxidation in HNO3. The DBD was used for the preparation of a very thin SiO2 layer on a-Si:H for the first time to our knowledge. Preliminary electrical measurements confirmed that a very low interface states density was detected in the case of the native oxide/a-Si:H and DBD oxide/a-Si:H
Field induced slow magnetic relaxation in a zig-zag chain-like Dy(iii) complex with the ligando-phenylenedioxydiacetato
The new complex [Dy(PDOA)(NO3)(H2O)(2)](n)center dot nH(2)O (1) (H(2)PDOA iso-phenylenedioxydiacetic acid) was isolated from the reaction of dysprosium(iii) nitrate and H(2)PDOA in a 1 : 1 molar ratio. Its crystal structure is formed of neutral zig-zag chains in which the nona-coordinated Dy(iii) atoms (O(9)donor set) are linked by PDOA ligands with a chelating-bridging coordination mode. DC and AC magnetic studies revealed that1behaves as a field-induced SMM with three relaxation channels. The derived values, considering the Orbach relaxation process, of the barrier to spin reversal and the extrapolated relaxation time areU/k(B)= 59.5 K and tau(0)= 6.3 x 10(-10)s, respectively.Ab initiocalculations support the experimental results
Virtual Electrode Design for Lithium-Ion Battery Cathodes
Microstructural characteristics of lithiumâion battery cathodes determine their performance. Thus, modern simulation tools are increasingly important for the custom design of multiphase cathodes. This work presents a new method for generating virtual, yet realistic cathode microstructures. A precondition is a 3D template of a commercial cathode, reconstructed via focused ion beam/scanning electron microscopy (FIB/SEM) tomography and appropriate algorithms. The characteristically shaped micrometerâsized active material (AM) particles and agglomerates of nanoâsized carbonâbinder (CB) particles are individually extracted from the voxelâbased templates. Thereby, a library of roughly 1100âAM particles and 20 CB agglomerates is created. Next, a virtual cathode microstructure is predefined, and representative sets of AM particles and CB agglomerates are built. The following reâassembly of AM particles within a predefined volume box works using dropping and rolling algorithms. Thereby, one can generate cathodes with specified characteristics, such as the volume fraction of AM, CB and pore space, particleâsize distributions, and gradients thereof. Naturally, such a virtual twin is a promising starting point for physicsâbased electrochemical performance models. The workflow from the commercial cathode microstructure through to a full virtual twin will be explained and assessed for a blend cathode made of the two AMs, LiNiCoAlO (NCA) and LiCoO (LCO)
Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities
Identifying patients at risk of traumatic brain injury (TBI) is important
because research suggests prophylactic treatments to reduce risk of long-term
sequelae. Blast pressure waves can cause TBI without penetrating wounds or
blunt force trauma. Similarly, bullet impacts distant from the brain can
produce pressure waves sufficient to cause mild to moderate TBI. The fluid
percussion model of TBI shows that pressure impulses of 15-30 psi cause mild to
moderate TBI in laboratory animals. In pigs and dogs, bullet impacts to the
thigh produce pressure waves in the brain of 18-45 psi and measurable injury to
neurons and neuroglia. Analyses of research in goats and epidemiological data
from shooting events involving humans show high correlations (r > 0.9) between
rapid incapacitation and pressure wave magnitude in the thoracic cavity. A case
study has documented epilepsy resulting from a pressure wave without the bullet
directly hitting the brain. Taken together, these results support the
hypothesis that bullet impacts distant from the brain produce pressure waves
that travel to the brain and can retain sufficient magnitude to induce brain
injury. The link to long-term sequelae could be investigated via
epidemiological studies of patients who were gunshot in the chest to determine
whether they experience elevated rates of epilepsy and other neurological
sequelae
Mild concussive head injury results in increased brain substance P immunoreactivity
The document attached has been archived with permission from the Medimond International Proceedings Division. An external link to the publisherâs web site is included.The neuroinflammatory neuropeptide substance P (SP) has been implicated in oedema development following traumatic brain injury. Whether the neuropeptide plays a role in concussive head injury is unknown. Accordingly, we have used a newly developed model of mild head injury in rats to characterise the release of SP following concussive brain injury. Following brain trauma, there was no evidence of motor or cognitive deficits over the ensuing 3 weeks. Despite this, increased SP immunoreactivity was present in perivascular axons, some pyramidal neurones and astrocytes when compared to sham animals. Our findings suggest that concussive brain injury predisposes an individual to diffuse brain swelling, which may have implications in the management of sports related concussion.J.J. Donkin, I. Cernak, K.M. Rodgers and R. Vinkhttp://www.medimond.com/proceedings/moreinfo/20040912.ht
Voice Analysis to Differentiate the Dopaminergic Response in People With Parkinson's Disease
Humans' voice offers the widest variety of motor phenomena of any human activity. However, its clinical evaluation in people with movement disorders such as Parkinson's disease (PD) lags behind current knowledge on advanced analytical automatic speech processing methodology. Here, we use deep learning-based speech processing to differentially analyze voice recordings in 14 people with PD before and after dopaminergic medication using personalized Convolutional Recurrent Neural Networks (p-CRNN) and Phone Attribute Codebooks (PAC). p-CRNN yields an accuracy of 82.35% in the binary classification of ON and OFF motor states at a sensitivity/specificity of 0.86/0.78. The PAC-based approach's accuracy was slightly lower with 73.08% at a sensitivity/specificity of 0.69/0.77, but this method offers easier interpretation and understanding of the computational biomarkers. Both p-CRNN and PAC provide a differentiated view and novel insights into the distinctive components of the speech of persons with PD. Both methods detect voice qualities that are amenable to dopaminergic treatment, including active phonetic and prosodic features. Our findings may pave the way for quantitative measurements of speech in persons with PD
NeuroSpeech
NeuroSpeech is a software for modeling pathological speech signals considering different speech dimensions: phonation, articulation, prosody, and intelligibility. Although it was developed to model dysarthric speech signals from Parkinson's patients, its structure allows other computer scientists or developers to include other pathologies and/or measures. Different tasks can be performed: (1) modeling of the signals considering the aforementioned speech dimensions, (2) automatic discrimination of Parkinson's vs. non-Parkinson's, and (3) prediction of the neurological state according to the Unified Parkinson's Disease Rating Scale (UPDRS) score. The prediction of the dysarthria level according to the Frenchay Dysarthria Assessment scale is also provided
The next-generation ARC middleware
The Advanced Resource Connector (ARC) is a light-weight, non-intrusive, simple yet powerful Grid middleware capable of connecting highly heterogeneous computing and storage resources. ARC aims at providing general purpose, flexible, collaborative computing environments suitable for a range of uses, both in science and business. The server side offers the fundamental job execution management, information and data capabilities required for a Grid. Users are provided with an easy to install and use client which provides a basic toolbox for job- and data management. The KnowARC project developed the next-generation ARC middleware, implemented as Web Services with the aim of standard-compliant interoperability
Joule-heating Effects In the Amorphous Fe40ni40b20 Alloy
The effects of Joule heating on the amorphous Fe40Ni40B20 alloy are investigated by measuring the time behavior of the electrical resistance of ribbon strips during such a treatment. The structural transformations occurring in subsequent stages of the process are studied by means of x-ray-diffraction, differential-scanning-calorimetry, and magnetic-permeability measurements. A continuous evolution from a fully amorphous to a fully crystalline structure may be followed. The crystallization mechanisms observed in Joule-heated samples differ from the ones occurring under conventional heating conditions. The electrical resistance displays a bump in the course of Joule heating. A quantitative model relating such a bump to the extra heat released to the sample by fast crystallization is proposed and discussed
Shear Forces during Blast, Not Abrupt Changes in Pressure Alone, Generate Calcium Activity in Human Brain Cells
Blast-Induced Traumatic Brain Injury (bTBI) describes a spectrum of injuries caused by an explosive force that results in changes in brain function. The mechanism responsible for primary bTBI following a blast shockwave remains unknown. We have developed a pneumatic device that delivers shockwaves, similar to those known to induce bTBI, within a chamber optimal for fluorescence microscopy. Abrupt changes in pressure can be created with and without the presence of shear forces at the surface of cells. In primary cultures of human central nervous system cells, the cellular calcium response to shockwaves alone was negligible. Even when the applied pressure reached 15 atm, there was no damage or excitation, unless concomitant shear forces, peaking between 0.3 to 0.7 Pa, were present at the cell surface. The probability of cellular injury in response to a shockwave was low and cell survival was unaffected 20 hours after shockwave exposure
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