139 research outputs found

    EXPERIMENTAL EVALUATION OF MODIFIED PHASE TRANSFORM FOR SOUND SOURCE DETECTION

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    The detection of sound sources with microphone arrays can be enhanced through processing individual microphone signals prior to the delay and sum operation. One method in particular, the Phase Transform (PHAT) has demonstrated improvement in sound source location images, especially in reverberant and noisy environments. Recent work proposed a modification to the PHAT transform that allows varying degrees of spectral whitening through a single parameter, andamp;acirc;, which has shown positive improvement in target detection in simulation results. This work focuses on experimental evaluation of the modified SRP-PHAT algorithm. Performance results are computed from actual experimental setup of an 8-element perimeter array with a receiver operating characteristic (ROC) analysis for detecting sound sources. The results verified simulation results of PHAT- andamp;acirc; in improving target detection probabilities. The ROC analysis demonstrated the relationships between various target types (narrowband and broadband), room reverberation levels (high and low) and noise levels (different SNR) with respect to optimal andamp;acirc;. Results from experiment strongly agree with those of simulations on the effect of PHAT in significantly improving detection performance for narrowband and broadband signals especially at low SNR and in the presence of high levels of reverberation

    Business Use Of Internet: A Critical Analysis And A Set Of Propositions

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    Analysis on frequency of missing mandibular first molar in medium aged adults – A Retrospective study

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    The retrospective study was conducted among patients visiting the out patient department of a private hospital, Chennai. The aim of the study was to identify the frequency of missing mandibular first molars in medium aged adults. Patients belonging to age group 35 to 75 years with missing mandibular first molar and patients who underwent extraction of mandibular first molar from June 2019 to March 2020 were selected for the study . The patients undergoing replacement of the missing teeth were also evaluated. The data was entered into the SPSS software by IBM and analyzed by descriptive analysis and Pearson correlation. The study population consisted of 1099 patients with missing or extracted mandibular first molar within the age group 35 to 75 years. We observed that the frequency of missing mandibular first molar is 12% among the medium aged adult population with missing teeth. Maximum number of patients with missing mandibular first molar belonged to the age group 35 to 45 years (66.33%) [p value= 0.002 - significant]. Around 50.05% of the study population did not undergo any replacement procedure and 49.95% underwent prosthodontic treatment for replacement of the missing mandibular first molar teeth .Out of which 23% underwent implant , 20.1% underwent TPD, 7% underwent Fixed dental prosthesis . The remaining 47.4% of the population did not undergo treatment of missing / extracted teeth

    Photoinduced electron transfer between a donor and an acceptor separated by a capsular wall

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    The efficient photoinduced electron transfer from a stilbene derivative incarcerated within a negatively charged organic nanocapsule to positively charged acceptors (methyl viologen and a pyridinium salt) adsorbed outside and the back electron transfer were controlled by supramolecular effects

    Retinal Organoids derived from hiPSCs of an AIPL1-LCA Patient Maintain Cytoarchitecture despite Reduced levels of Mutant AIPL1

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    Aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) is a photoreceptor-specific chaperone that stabilizes the effector enzyme of phototransduction, cGMP phosphodiesterase 6 (PDE6). Mutations in the AIPL1 gene cause a severe inherited retinal dystrophy, Leber congenital amaurosis type 4 (LCA4), that manifests as the loss of vision during the first year of life. In this study, we generated three-dimensional (3D) retinal organoids (ROs) from human induced pluripotent stem cells (hiPSCs) derived from an LCA4 patient carrying a Cys89Arg mutation in AIPL1. This study aimed to (i) explore whether the patient hiPSC-derived ROs recapitulate LCA4 disease phenotype, and (ii) generate a clinically relevant resource to investigate the molecular mechanism of disease and safely test novel therapies for LCA4 in vitro. We demonstrate reduced levels of the mutant AIPL1 and PDE6 proteins in patient organoids, corroborating the findings in animal models; however, patient-derived organoids maintained retinal cell cytoarchitecture despite significantly reduced levels of AIPL1.This work was supported by Institute of Health Carlos III (ISCIII)/ ERDF (European Research Development Fund), Spain, ((PI16/00409 (DL); DL, AAC, and SE are members of PRB3 supported by a grant (PT17/0019/0024) of the PE I + D + i 2013–2016, funded by ISCIII and ERDF. The work was also supported by ISCIII-ERDF (PI16/00425), CIBERER 06/07/0036, IIS-FJD Biobank PT13/0010/0012, RAREGENOMICS funded by Regional Government of Madrid, (CAM, B2017/BMD3721) and ERDF, the University Chair UAM-IIS-FJD of Genomic Medicine, the Spanish National Organization of the Blind (ONCE), the Spanish Fighting Blindness Foundation (FUNDALUCE), and the Ramon Areces Foundation. MC is supported by the Miguel Servet Program (CPII17_00006) from ISCIII. DL is supported by Miguel Servet I Program (CP18/00033). VR is supported by National Institute of Health (R01 EY028035, R01 EY025536). Transcriptome profiling and analyses were supported by the Intramural Research Program of the National Eye Institute (ZIAEY000450, ZIAEY000474) and utilized the high-performance computational capabilities of the Biowulf Linux cluster at NIH (http://biowulf.nih.gov)

    Outcomes of elective liver surgery worldwide: a global, prospective, multicenter, cross-sectional study

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    Background: The outcomes of liver surgery worldwide remain unknown. The true population-based outcomes are likely different to those vastly reported that reflect the activity of highly specialized academic centers. The aim of this study was to measure the true worldwide practice of liver surgery and associated outcomes by recruiting from centers across the globe. The geographic distribution of liver surgery activity and complexity was also evaluated to further understand variations in outcomes. Methods: LiverGroup.org was an international, prospective, multicenter, cross-sectional study following the Global Surgery Collaborative Snapshot Research approach with a 3-month prospective, consecutive patient enrollment within January–December 2019. Each patient was followed up for 90 days postoperatively. All patients undergoing liver surgery at their respective centers were eligible for study inclusion. Basic demographics, patient and operation characteristics were collected. Morbidity was recorded according to the Clavien–Dindo Classification of Surgical Complications. Country-based and hospital-based data were collected, including the Human Development Index (HDI). (NCT03768141). Results: A total of 2159 patients were included from six continents. Surgery was performed for cancer in 1785 (83%) patients. Of all patients, 912 (42%) experienced a postoperative complication of any severity, while the major complication rate was 16% (341/2159). The overall 90-day mortality rate after liver surgery was 3.8% (82/2,159). The overall failure to rescue rate was 11% (82/ 722) ranging from 5 to 35% among the higher and lower HDI groups, respectively. Conclusions: This is the first to our knowledge global surgery study specifically designed and conducted for specialized liver surgery. The authors identified failure to rescue as a significant potentially modifiable factor for mortality after liver surgery, mostly related to lower Human Development Index countries. Members of the LiverGroup.org network could now work together to develop quality improvement collaboratives

    The Radiologist and the Surgeon: The Journey from a Support Staff to the Most Valuable Player of the Clinical Team

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    AbstractAdvancement in understanding of disease and availability of state-of-the-art tools for diagnosis and management have brought the radiologist and the surgeon closer. Close cooperation between them starting from initial presentation to postoperative follow-up spanning diagnosis, staging, treatment planning, interventions to management of disease sequelae, and complications has become the norm. This has benefited both clinicians and patients alike. Although better tools help in increasing accuracy, accuracy by itself does not imply precision. Technology cannot be a substitute for good clinical acumen or interaction between the surgeon and the radiologist. It is desirable that radiologists working in tertiary referral centers focus on two or three system-based specialties, so that they can keep pace with the latest developments in the field and deliver quality care. The new-age radiologist and surgeon should adapt to this changing scenario and increasing expectations. In the pursuit of clinical excellence, the radiologist has become the most valuable player in the clinical team.</jats:p
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