32 research outputs found

    Improving the Speech Intelligibility By Cochlear Implant Users

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    In this thesis, we focus on improving the intelligibility of speech for cochlear implants (CI) users. As an auditory prosthetic device, CI can restore hearing sensations for most patients with profound hearing loss in both ears in a quiet background. However, CI users still have serious problems in understanding speech in noisy and reverberant environments. Also, bandwidth limitation, missing temporal fine structures, and reduced spectral resolution due to a limited number of electrodes are other factors that raise the difficulty of hearing in noisy conditions for CI users, regardless of the type of noise. To mitigate these difficulties for CI listener, we investigate several contributing factors such as the effects of low harmonics on tone identification in natural and vocoded speech, the contribution of matched envelope dynamic range to the binaural benefits and contribution of low-frequency harmonics to tone identification in quiet and six-talker babble background. These results revealed several promising methods for improving speech intelligibility for CI patients. In addition, we investigate the benefits of voice conversion in improving speech intelligibility for CI users, which was motivated by an earlier study showing that familiarity with a talker’s voice can improve understanding of the conversation. Research has shown that when adults are familiar with someone’s voice, they can more accurately – and even more quickly – process and understand what the person is saying. This theory identified as the “familiar talker advantage” was our motivation to examine its effect on CI patients using voice conversion technique. In the present research, we propose a new method based on multi-channel voice conversion to improve the intelligibility of transformed speeches for CI patients

    The investigation of relevancy between PIAS1 and PIAS2 gene expression and disease severity of multiple sclerosis

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    Introduction: PIAS1 and PIAS2 (protein inhibitor of activated STAT 1,2) play key roles in the pathogenesis of autoimmune and inflammatory diseases. This study aims to evaluate the gene expression of these factors in multiple sclerosis (MS) patients compared to healthy individuals and correlate them with the severity of MS. Materials and methods: Sixty participants, including 30 patients with MS and 30 healthy controls were studied. The expression of PIAS1 and PIAS2 genes in peripheral blood samples of all participants was measured by real-time PCR. The severity of MS was evaluated using the Expanded Disability Status Scale (EDSS). Finally, we evaluated the correlation between the expression of PIAS1 and PIAS2 genes with disease severity. Results: The expression of PIAS1 gene was increased in patients with MS compared to healthy subjects (P value<.001). Also, there was a significant correlation between the expression of PIAS1 and PIAS2 genes with disease severity according to EDSS. Conclusion: Our study suggests the expression of PIAS1 and PIAS2 genes as a prognostic and diagnostic marker in MS disease. © 2019, © 2019 Taylor & Francis

    Flight and Direct to Earth/Space Relay Communication System Architecture for GSFC CubeSat Missions

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    The CubeSat platform is finding increasing use in space science applications due to its low cost and comparative ease of launch. It is becoming a key scientific discovery tool in low Earth orbit (LEO) and beyond, including geosynchronous equatorial orbit (GEO), the Lagrange Points, Lunar missions, and more. The increasing complexity of these missions and their scientific goals must be supported by equal advancements in communications technology. Higher data rates and greater reliability are required every year. However, the reduced Size, Weight, and Power (SWaP) constraints of CubeSat platforms introduce unique challenges in the area of satellite communications. There is currently a lack of communication equipment tailored specifically to the CubeSat platform. This lack of standardized, tested equipment extends development time and reduces mission confidence. Furthermore, missions utilizing the CubeSat platform are often subject to more difficult design constraints. Antenna placement, size, and pointing are often subordinate to the requirements of the payload instruments and mission goals. Traditional link margin estimation techniques are insufficient in these cases, as they emphasize worst case scenarios. In reality the actual link parameters may vary widely even during a single pass. This presents new challenges in predicting communications performance and scheduling ground station contacts, but also new opportunities for improving efficiency. This paper presents the integration, testing, and validation process for a new software defined radio (SDR) designed for the CubeSat platform in conjunction with Vulcan Wireless, Inc. The SDR is planned for use on 5 upcoming CubeSat missions at NASAs Goddard Space Flight Center (GSFC) including a Geosynchronous Transfer Orbit (GTO) mission and it may also serve as a standard and well-tested option for future missions by enabling a standardized, rapid and low cost CubeSat communication system network integration process. Detailed simulations have been developed to estimate the communication performance of these missions, taking the unique antenna placements and attitude behavior of each satellite into account. These simulations allow a much more accurate analysis of the expected link margin, which varies considerably during each pass for the NASA Space Relay (SR) and Direct to Earth (DTE) network. The modelling procedures are outlined, and the results are used to predict communications performance of the missions

    Association between Immunofluorescence Pattern and Mucosal Involvement in Patients with Bullous Pemphigoid

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    Bullous pemphigoid is an acquired autoimmune subepidermal blistering disease which is associated with mucocutaneous lesions. The type and amount of autoantibody deposition may have a role in mucosal lesions. We studied the association between mucosal involvement and direct immunofluorescence pattern in cutaneous lesions of patients with bullous pemphigoid. In this retrospective analytical cross-sectional study, we studied the demographic data, clinical presentations, and immunopathological findings of 69 patients with bullous pemphigoid admitted to our hospital 2008-2016. Patients were allocated into two groups on the basis of the mucosal involvement, and direct immunofluorescence patterns were evaluated. The data were analyzed using SPSS version18. The mean age of patients was 70.9±14.97 (mean ± Standard Deviation) years old. In our study, 56.5% of patients were women. All patients showed deposition of IgG and C3 in the dermoepidermal junction, with different severity. Patients with mucosal involvement (40.6% of cases) had a more prominent deposition of IgG, IgA, and C3 at the dermoepidermal junction compared with patients without mucosal involvement, which represented a statistically significant difference (P&lt;0.05). Logistic regression analysis showed that lower age, IgA, and C3 deposition (P&lt;0.05) were associated with mucosal involvement. Deposition of IgA and C3 (in addition to IgG) at the dermoepidermal junction seems to be a marker of mucosal involvement in patients with bullous pemphigoid. Attention to direct immunofluorescence pattern in patients with bullous pemphigoid may be helpful in prediction of mucosal involvement in these patients. </p

    S-Band Transponder Multi-Network Compatibility, Space Environment and Radiation Testing

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    This paper presents the development and testing of the Software Define Radio (SDR) transceiver to meet the emerging needs for SmallSat communication and navigation. Vulcan Wireless and NASA Goddard Space Flight Center (GSFC) collaborated in testing the Vulcan Wireless S-band SDR engineering model. Apart from testing, communication link analysis was performed for a Low Earth Orbit (LEO) 400 km scenario. The results of the compatibility, radiation, environmental testing, and link analysis are presented. Also, this paper reviews a set of SmallSat missions under development at NASA GSFC

    Dellingr: Reliability Lessons Learned from On-Orbit

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    Dellingr, NASA Goddard Space Flight Center’s (GSFC) first 6U CubeSat, was deployed from the International Space Station (ISS) on November 20, 2017. The primary objective of the mission was to apply and appropriately tailor GSFC knowledge and capability to design and build a CubeSat that increased resiliency and capability, while containing costs. The Dellingr spacecraft is a mixture of COTS and in-house components and includes two science instruments – an advanced gated time-of-flight ion-neutral mass spectrometer (INMS) and a boom mounted fluxgate. While a traditional GSFC spacecraft approach includes detailed analysis, design, testing, and extensive reviews, the Dellingr team adopted a “build, test, fix” approach to identify and correct potential mission ending issues. Yet, despite extensive testing, Dellingr immediately experienced unexpected major anomalies once on orbit. Using a flatsat and the insight gained from extensive on-orbit engineering data, the team was able to alleviate some of these anomalies and recover some of the lost functionality. The extensive set of lessons-learned is driving changes to our systems architecture, flight software, and testing approaches, and has provided valuable insight into what is required to produce a NASA CubeSat science mission with a moderate assurance of mission success, while containing resource requirements

    Detection of Carious Lesions and Restorations Using Particle Swarm Optimization Algorithm

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    Background/Purpose. In terms of the detection of tooth diagnosis, no intelligent detection has been done up till now. Dentists just look at images and then they can detect the diagnosis position in tooth based on their experiences. Using new technologies, scientists will implement detection and repair of tooth diagnosis intelligently. In this paper, we have introduced one intelligent method for detection using particle swarm optimization (PSO) and our mathematical formulation. This method was applied to 2D special images. Using developing of our method, we can detect tooth diagnosis for all of 2D and 3D images. Materials and Methods. In recent years, it is possible to implement intelligent processing of images by high efficiency optimization algorithms in many applications especially for detection of dental caries and restoration without human intervention. In the present work, we explain PSO algorithm with our detection formula for detection of dental caries and restoration. Also image processing helped us to implement our method. And to do so, pictures taken by digital radiography systems of tooth are used. Results and Conclusion. We implement some mathematics formula for fitness of PSO. Our results show that this method can detect dental caries and restoration in digital radiography pictures with the good convergence. In fact, the error rate of this method was 8%, so that it can be implemented for detection of dental caries and restoration. Using some parameters, it is possible that the error rate can be even reduced below 0.5%

    Association between Immunofluorescence Pattern and Mucosal Involvement in Patients with Bullous Pemphigoid

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    Bullous pemphigoid is an acquired autoimmune subepidermal blistering disease which is associated with mucocutaneous lesions. The type and amount of autoantibody deposition may have a role in mucosal lesions. We studied the association between mucosal involvement and direct immunofluorescence pattern in cutaneous lesions of patients with bullous pemphigoid. In this retrospective analytical cross-sectional study, we studied the demographic data, clinical presentations, and immunopathological findings of 69 patients with bullous pemphigoid admitted to our hospital 2008-2016. Patients were allocated into two groups on the basis of the mucosal involvement, and direct immunofluorescence patterns were evaluated. The data were analyzed using SPSS version18. The mean age of patients was 70.9±14.97 (mean ± Standard Deviation) years old. In our study, 56.5% of patients were women. All patients showed deposition of IgG and C3 in the dermoepidermal junction, with different severity. Patients with mucosal involvement (40.6% of cases) had a more prominent deposition of IgG, IgA, and C3 at the dermoepidermal junction compared with patients without mucosal involvement, which represented a statistically significant difference (P&lt;0.05). Logistic regression analysis showed that lower age, IgA, and C3 deposition (P&lt;0.05) were associated with mucosal involvement. Deposition of IgA and C3 (in addition to IgG) at the dermoepidermal junction seems to be a marker of mucosal involvement in patients with bullous pemphigoid. Attention to direct immunofluorescence pattern in patients with bullous pemphigoid may be helpful in prediction of mucosal involvement in these patients. </p

    GTOSat: Radiation Belt Dynamics from the Inside

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    GTOSat, a 6U SmallSat integrated and tested at NASA Goddard Space Flight Center (GSFC), has a scheduled launch date of July 31st, 2022, on an Atlas V. From a low inclination geosynchronous transfer orbit (GTO), GTOSat has the primary science goal of advancing our quantitative understanding of acceleration and loss of relativistic electrons in the Earth’s outer radiation belt. It will measure energy spectra and pitch angles of both the seed and the energized electron populations simultaneously using a compact, high-heritage Relativistic Electron Magnetic Spectrometer (REMS) built by The Aerospace Corporation. A boom-mounted Fluxgate Magnetometer (FMAG), developed by NASA GSFC, will provide 3-axis knowledge of the ambient local magnetic field. The spacecraft bus uses a combination of commercial and in-house/custom designed components. Design, integration, and testing of the spacecraft bus was performed by a small, dedicated team at GSFC. Throughout development GTOSat has encountered numerous challenges, expected and unexpected, that we’re ready to share with the community

    The global, regional, and national burden of cirrhosis by cause in 195 countries and territories, 1990-2017 : a systematic analysis for the Global Burden of Disease Study 2017

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    Background Cirrhosis and other chronic liver diseases (collectively referred to as cirrhosis in this paper) are a major cause of morbidity and mortality globally, although the burden and underlying causes differ across locations and demographic groups. We report on results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 on the burden of cirrhosis and its trends since 1990, by cause, sex, and age, for 195 countries and territories. Methods We used data from vital registrations, vital registration samples, and verbal autopsies to estimate mortality. We modelled prevalence of total, compensated, and decompensated cirrhosis on the basis of hospital and claims data. Disability-adjusted life-years (DALYs) were calculated as the sum of years of life lost due to premature death and years lived with disability. Estimates are presented as numbers and age-standardised or age-specific rates per 100 000 population, with 95% uncertainty intervals (UIs). All estimates are presented for five causes of cirrhosis: hepatitis B, hepatitis C, alcohol-related liver disease, non-alcoholic steatohepatitis (NASH), and other causes. We compared mortality, prevalence, and DALY estimates with those expected according to the Socio-demographic Index (SDI) as a proxy for the development status of regions and countries. Findings In 2017, cirrhosis caused more than 1.32 million (95% UI 1.27-1.45) deaths (440000 [416 000-518 000; 33.3%] in females and 883 000 [838 000-967 000; 66.7%] in males) globally, compared with less than 899 000 (829 000-948 000) deaths in 1990. Deaths due to cirrhosis constituted 2.4% (2.3-2.6) of total deaths globally in 2017 compared with 1.9% (1.8-2.0) in 1990. Despite an increase in the number of deaths, the age-standardised death rate decreased from 21.0 (19.2-22.3) per 100 000 population in 1990 to 16.5 (15.8-18-1) per 100 000 population in 2017. Sub-Saharan Africa had the highest age-standardised death rate among GBD super-regions for all years of the study period (32.2 [25.8-38.6] deaths per 100 000 population in 2017), and the high-income super-region had the lowest (10.1 [9.8-10-5] deaths per 100 000 population in 2017). The age-standardised death rate decreased or remained constant from 1990 to 2017 in all GBD regions except eastern Europe and central Asia, where the age-standardised death rate increased, primarily due to increases in alcohol-related liver disease prevalence. At the national level, the age-standardised death rate of cirrhosis was lowest in Singapore in 2017 (3.7 [3.3-4.0] per 100 000 in 2017) and highest in Egypt in all years since 1990 (103.3 [64.4-133.4] per 100 000 in 2017). There were 10.6 million (10.3-10.9) prevalent cases of decompensated cirrhosis and 112 million (107-119) prevalent cases of compensated cirrhosis globally in 2017. There was a significant increase in age-standardised prevalence rate of decompensated cirrhosis between 1990 and 2017. Cirrhosis caused by NASH had a steady age-standardised death rate throughout the study period, whereas the other four causes showed declines in age-standardised death rate. The age-standardised prevalence of compensated and decompensated cirrhosis due to NASH increased more than for any other cause of cirrhosis (by 33.2% for compensated cirrhosis and 54.8% for decompensated cirrhosis) over the study period. From 1990 to 2017, the number of prevalent cases snore than doubled for compensated cirrhosis due to NASH and more than tripled for decompensated cirrhosis due to NASH. In 2017, age-standardised death and DALY rates were lower among countries and territories with higher SDI. Interpretation Cirrhosis imposes a substantial health burden on many countries and this burden has increased at the global level since 1990, partly due to population growth and ageing. Although the age-standardised death and DALY rates of cirrhosis decreased from 1990 to 2017, numbers of deaths and DALYs and the proportion of all global deaths due to cirrhosis increased. Despite the availability of effective interventions for the prevention and treatment of hepatitis B and C, they were still the main causes of cirrhosis burden worldwide, particularly in low-income countries. The impact of hepatitis B and C is expected to be attenuated and overtaken by that of NASH in the near future. Cost-effective interventions are required to continue the prevention and treatment of viral hepatitis, and to achieve early diagnosis and prevention of cirrhosis due to alcohol-related liver disease and NASH. Copyright (C) 2020 The Author(s). Published by Elsevier Ltd.Peer reviewe
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