LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 1906

Search options

  1. Article ; Online: The effects of estimation accuracy, estimation approach, and number of selected channels using formant-priority channel selection for an "n-of-m" sound processing strategy for cochlear implants.

    Saba, Juliana N / Ali, Hussnain / Hansen, John H L

    The Journal of the Acoustical Society of America

    2023  Volume 153, Issue 5, Page(s) 3100

    Abstract: ... in an l-of-n-of-m-based signal processing strategy to provide important voicing information independent ... the effects of estimation approach and number of selected channels (n). A significant effect of estimation ...

    Abstract Previously, selection of l channels was prioritized according to formant frequency locations in an l-of-n-of-m-based signal processing strategy to provide important voicing information independent of listening environments for cochlear implant (CI) users. In this study, ideal, or ground truth, formants were incorporated into the selection stage to determine the effect of accuracy on (1) subjective speech intelligibility, (2) objective channel selection patterns, and (3) objective stimulation patterns (current). An average +11% improvement (p < 0.05) was observed across six CI users in quiet, but not for noise or reverberation conditions. Analogous increases in channel selection and current for the upper range of F1 and a decrease across mid-frequencies with higher corresponding current, were both observed at the expense of noise-dominant channels. Objective channel selection patterns were analyzed a second time to determine the effects of estimation approach and number of selected channels (n). A significant effect of estimation approach was only observed in the noise and reverberation condition with minor differences in channel selection and significantly decreased stimulated current. Results suggest that estimation method, accuracy, and number of channels in the proposed strategy using ideal formants may improve intelligibility when corresponding stimulated current of formant channels are not masked by noise-dominant channels.
    MeSH term(s) Cochlear Implants ; Speech Perception ; Cochlear Implantation ; Sound ; Noise
    Language English
    Publishing date 2023-05-24
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 219231-7
    ISSN 1520-8524 ; 0001-4966
    ISSN (online) 1520-8524
    ISSN 0001-4966
    DOI 10.1121/10.0019416
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Weighted Burgers Vector analysis of orientation fields from high-angular resolution electron backscatter diffraction.

    Gardner, Joe / Wallis, David / Hansen, Lars N / Wheeler, John

    Ultramicroscopy

    2023  Volume 257, Page(s) 113893

    Abstract: The Weighted Burgers Vector (WBV) method can extract information about dislocation types and densities present in distorted crystalline materials from electron backscatter diffraction (EBSD) maps, using no assumptions about which slip systems might be ... ...

    Abstract The Weighted Burgers Vector (WBV) method can extract information about dislocation types and densities present in distorted crystalline materials from electron backscatter diffraction (EBSD) maps, using no assumptions about which slip systems might be present. Furthermore, high-angular resolution EBSD (HR-EBSD) uses a cross-correlation procedure to increase the angular precision of EBSD measurements by an order of magnitude compared to conventional EBSD. However, the WBV technique has not previously been applied to HR-EBSD data and therefore it remains unclear as to which low-angle substructures can be reliably characterised by WBV analysis of conventional EBSD data and which require additional HR-EBSD processing. To establish some practical examples that can be used to guide future data-acquisition strategies, we compare the output of the WBV method when applied to conventional EBSD data and HR-EBSD data collected from the most common minerals in Earth's lower crust (plagioclase feldspar) and upper mantle (olivine). The results demonstrate that HR-EBSD and WBV processing are complementary techniques. The increase in angular precision achieved with HR-EBSD processing allows low-angle (on the order of 0.1°) structures, which are obscured by noise in conventional EBSD data, to be analyzed quantitatively using the WBV method. Combining the WBV and HR-EBSD methods increases the precision of calculated WBV directions, which is essential when using information about active slip systems to infer likely deformation mechanisms from naturally deformed microstructures. This increase in precision is particularly important for low-symmetry crystals, such as plagioclase, that have a wide range of available slip systems that vary in relative activity with changing pressure, temperature and differential stress. Because WBV directions are calculated using no assumptions about which slip systems may be present, combining this technique with HR-EBSD to refine the precision of lattice orientation gradients is ideal for investigating complex natural materials with unknown deformation histories.
    Language English
    Publishing date 2023-11-24
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 1479043-9
    ISSN 1879-2723 ; 0304-3991
    ISSN (online) 1879-2723
    ISSN 0304-3991
    DOI 10.1016/j.ultramic.2023.113893
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article ; Online: The effects of Lombard perturbation on speech intelligibility in noise for normal hearing and cochlear implant listeners.

    Saba, Juliana N / Hansen, John H L

    The Journal of the Acoustical Society of America

    2022  Volume 151, Issue 2, Page(s) 1007

    Abstract: Natural compensation of speech production in challenging listening environments is referred to as the Lombard effect (LE). The resulting acoustic differences between neutral and Lombard speech have been shown to provide intelligibility benefits for ... ...

    Abstract Natural compensation of speech production in challenging listening environments is referred to as the Lombard effect (LE). The resulting acoustic differences between neutral and Lombard speech have been shown to provide intelligibility benefits for normal hearing (NH) and cochlear implant (CI) listeners alike. Motivated by this outcome, three LE perturbation approaches consisting of pitch, duration, formant, intensity, and spectral contour modifications were designed specifically for CI listeners to combat speech-in-noise performance deficits. Experiment 1 analyzed the effects of loudness, quality, and distortion of approaches on speech intelligibility with and without formant-shifting. Significant improvements of +9.4% were observed in CI listeners without the formant-shifting approach at +5 dB signal-to-noise ratio (SNR) large-crowd-noise (LCN) when loudness was controlled, however, performance was found to be significantly lower for NH listeners. Experiment 2 evaluated the non-formant-shifting approach with additional spectral contour and high pass filtering to reduce spectral smearing and decrease distortion observed in Experiment 1. This resulted in significant intelligibility benefits of +30.2% for NH and +21.2% for CI listeners at 0 and +5 dB SNR LCN, respectively. These results suggest that LE perturbation may be useful as front-end speech modification approaches to improve intelligibility for CI users in noise.
    MeSH term(s) Acoustic Stimulation/methods ; Cochlear Implants ; Hearing ; Speech Intelligibility ; Speech Perception
    Language English
    Publishing date 2022-03-01
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 219231-7
    ISSN 1520-8524 ; 0001-4966
    ISSN (online) 1520-8524
    ISSN 0001-4966
    DOI 10.1121/10.0009377
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: Extracellular vesicles from activated platelets possess a phospholipid-rich biomolecular profile and enhance prothrombinase activity.

    Guerreiro, Eduarda M / Kruglik, Sergei G / Swamy, Samantha / Latysheva, Nadezhda / Østerud, Bjarne / Guigner, Jean-Michel / Sureau, Franck / Bonneau, Stephanie / Kuzmin, Andrey N / Prasad, Paras N / Hansen, John-Bjarne / Hellesø, Olav Gaute / Snir, Omri

    Journal of thrombosis and haemostasis : JTH

    2024  Volume 22, Issue 5, Page(s) 1463–1474

    Abstract: Background: Extracellular vesicles (EVs), in particular those derived from activated platelets, are associated with a risk of future venous thromboembolism.: Objectives: To study the biomolecular profile and function characteristics of EVs from ... ...

    Abstract Background: Extracellular vesicles (EVs), in particular those derived from activated platelets, are associated with a risk of future venous thromboembolism.
    Objectives: To study the biomolecular profile and function characteristics of EVs from control (unstimulated) and activated platelets.
    Methods: Biomolecular profiling of single or very few (1-4) platelet-EVs (control/stimulated) was performed by Raman tweezers microspectroscopy. The effects of such EVs on the coagulation system were comprehensively studied.
    Results: Raman tweezers microspectroscopy of platelet-EVs followed by biomolecular component analysis revealed for the first time 3 subsets of EVs: (i) protein rich, (ii) protein/lipid rich, and (iii) lipid rich. EVs from control platelets presented a heterogeneous biomolecular profile, with protein-rich EVs being the main subset (58.7% ± 3.5%). Notably, the protein-rich subset may contain a minor contribution from other extracellular particles, including protein aggregates. In contrast, EVs from activated platelets were more homogeneous, dominated by the protein/lipid-rich subset (>85%), and enriched in phospholipids. Functionally, EVs from activated platelets increased thrombin generation by 52.4% and shortened plasma coagulation time by 34.6% ± 10.0% compared with 18.6% ± 13.9% mediated by EVs from control platelets (P = .015). The increased procoagulant activity was predominantly mediated by phosphatidylserine. Detailed investigation showed that EVs from activated platelets increased the activity of the prothrombinase complex (factor Va:FXa:FII) by more than 6-fold.
    Conclusion: Our study reports a novel quantitative biomolecular characterization of platelet-EVs possessing a homogenous and phospholipid-enriched profile in response to platelet activation. Such characteristics are accompanied with an increased phosphatidylserine-dependent procoagulant activity. Further investigation of a possible role of platelet-EVs in the pathogenesis of venous thromboembolism is warranted.
    MeSH term(s) Humans ; Blood Platelets/metabolism ; Extracellular Vesicles/metabolism ; Phospholipids/metabolism ; Platelet Activation ; Blood Coagulation ; Spectrum Analysis, Raman ; Thrombin/metabolism ; Thromboplastin/metabolism ; Enzyme Activation
    Chemical Substances Phospholipids ; Thrombin (EC 3.4.21.5) ; Thromboplastin (9035-58-9)
    Language English
    Publishing date 2024-01-22
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2112661-6
    ISSN 1538-7836 ; 1538-7933
    ISSN (online) 1538-7836
    ISSN 1538-7933
    DOI 10.1016/j.jtha.2024.01.004
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Transoral Robotic Surgery and Radiation Volume Deintensification in Unknown Primary Squamous Cell Carcinoma of the Neck: The Phase 2 FIND Nonrandomized Controlled Trial.

    de Almeida, John R / Martino, Rosemary / Hosni, Ali / Goldstein, David P / Bratman, Scott V / Chepeha, Douglas B / Waldron, John N / Weinreb, Ilan / Perez-Ordonez, Bayardo / Yu, Eugene / Metser, Ur / Hansen, Aaron R / Xu, Wei / Su, Susie Jie / Kim, John

    JAMA otolaryngology-- head & neck surgery

    2024  

    Abstract: ... conducted from January 2021 to June 2022.: Intervention: Diagnostic- (n = 13) or therapeutic-intent (n ...

    Abstract Importance: Patients with unknown primary squamous cell carcinoma (CUP) with cervical metastases typically receive comprehensive radiotherapy (RT) of the pharynx and bilateral neck. Typically, these patients receive comprehensive RT of the pharynx and bilateral neck that may produce treatment-related toxic effects.
    Objective: To determine whether localization of occult oropharyngeal cancers with transoral robotic surgery (TORS) combined with reduced pharyngeal and neck RT volumes provides acceptable disease control.
    Design, setting, and participants: This phase 2, single-group nonrandomized controlled trial at a single institution accrued 32 prospective participants with p16-positive CUP without a primary squamous cell carcinoma on examination and imaging from 2017 to 2019, and 24-month follow-up. The data analysis was conducted from January 2021 to June 2022.
    Intervention: Diagnostic- (n = 13) or therapeutic-intent (n = 9) TORS, with pharyngeal-sparing radiotherapy (PSRT) prescribed for negative margins or pT0, and unilateral neck RT (UNRT) prescribed for unilateral lymphadenopathy with lateralized primary tumor or pT0.
    Main outcomes and measures: Out-of-radiation treatment volume failure (<15% was hypothesized to be acceptable) and reports of local and regional recurrence, overall survival, toxic effects, swallowing outcomes (per the MD Anderson Dysphagia Inventory), and videofluoroscopic swallow (per Dynamic Imaging Grade of Swallowing Toxic Effects [DIGEST]) ratings.
    Results: The study sample comprised 22 patients (mean [SD] age, 59.1 [5.7] years; 3 [14%] females and 19 [86%] male) with CUP. Of these, 19 patients (86%) had tumor stage cN1; 2 (9%), cN2; and 1 (5%), cN3. Five patients (23%), 14 patients (64%), and 3 patients (13%) had 0, 1, or 2 primary tumors, respectively. Twenty patients received RT; of these, 9 patients (45%) underwent PSRT and 10 patients (50%), UNRT. In the diagnostic-intent group, 8 patients (62%) and 5 patients (38%) underwent RT and RT-concurrent chemotherapy, respectively. In the therapeutic-intent group, 6 patients (67%) and 1 patient (11%) received adjuvant RT-concurrent chemotherapy, respectively; 2 patients declined RT. Two-year out-of-radiation treatment volume failure, locoregional control, distant metastasis control, and overall survival were 0%, 100%, 95%, and 100%, respectively. Grade 3 or 4 surgical, acute, and late toxic effects occurred in 2 (9%), 5 (23%), and 1 (5%) patients, respectively. PSRT was associated with lower RT dose to superior constrictors (37 vs 53 Gy; mean difference, 16 Gy; 95% CI, 6.4, 24.9), smaller decline in swallowing scores during treatment (19.3 vs 39.7; mean difference, -20.4; 95% CI, -34.1 to -6.1), and fewer patients with worsening DIGEST grade on findings of videofluoroscopic swallow studies at 2 years (0% vs 60%; difference, 60%; 95% CI, 30% to 90%).
    Conclusions and relevance: These findings indicate that TORS for p16-positive CUP allows RT volume deintensification with excellent outcomes and support future investigation in randomized clinical trials.
    Trial registration: ClinicalTrials.gov Identifier: NCT03281499.
    Language English
    Publishing date 2024-04-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2701825-8
    ISSN 2168-619X ; 2168-6181
    ISSN (online) 2168-619X
    ISSN 2168-6181
    DOI 10.1001/jamaoto.2024.0423
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Familiar and unfamiliar speaker recognition assessment and system emulation for cochlear implant users.

    Mamun, Nursadul / Ghosh, Ria / Hansen, John H L

    The Journal of the Acoustical Society of America

    2023  Volume 153, Issue 2, Page(s) 1293

    Abstract: In the area of speech processing, human speaker identification under naturalistic environments is a challenging task, especially for hearing-impaired individuals with cochlear implants (CIs) or hearing aids (HAs). Motivated by the fact that ... ...

    Abstract In the area of speech processing, human speaker identification under naturalistic environments is a challenging task, especially for hearing-impaired individuals with cochlear implants (CIs) or hearing aids (HAs). Motivated by the fact that electrodograms reflect direct CI stimulation of input audio, this study proposes a speaker identification (ID) investigation using two-dimensional electrodograms constructed from the responses of a CI auditory system to emulate CI speaker ID capabilities. Features are extracted from electrodograms through an identity vector (i-vector) framework to train and generate identity models for each speaker using a Gaussian mixture model-universal background model followed by probabilistic linear discriminant analysis. To validate the proposed system, perceptual speaker ID for 20 normal hearing (NH) and seven CI listeners was evaluated with a total of 41 different speakers and compared with the scores from the proposed system. A one-way analysis of variance showed that the proposed system can reliably predict the speaker ID capability of CI (F[1,10] = 0.18, p = 0.68) and NH (F[1,20] = 0, p = 0.98) listeners in naturalistic environments. The impact of speaker familiarity is also addressed, and the results show a reduced performance for speaker recognition by CI subjects using their CI processor, highlighting limitations of current speech processing strategies used in CIs/HAs.
    MeSH term(s) Humans ; Cochlear Implants ; Cochlear Implantation ; Hearing Aids ; Persons With Hearing Impairments ; Discriminant Analysis
    Language English
    Publishing date 2023-02-28
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 219231-7
    ISSN 1520-8524 ; 0001-4966
    ISSN (online) 1520-8524
    ISSN 0001-4966
    DOI 10.1121/10.0017216
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: COVID-19 and preeclampsia with severe features at 34-weeks gestation.

    Hansen, John N / Hine, Jason / Strout, Tania D

    The American journal of emergency medicine

    2020  Volume 39, Page(s) 252.e3–252.e5

    Abstract: The evolving coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a rapid expansion of knowledge on the disease's clinical manifestations, laboratory and radiographic ... ...

    Abstract The evolving coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a rapid expansion of knowledge on the disease's clinical manifestations, laboratory and radiographic abnormalities, and patient trajectories. One area of particular focus is the effect that this illness may have on pregnancy and maternal-fetal disease. As of April 24, 2020, we identified 55 English language reports in the scientific literature summarizing data for 339 women and 258 fetuses and neonates. The majority of these data have focused on maternal-fetal transmission and neonatal outcomes. One systematic review and meta-analysis including the spectrum of coronaviruses [Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and COVID-19] in pregnancy noted increased rates of adverse outcomes associated with this group of infections. Here, we report the case of a COVID-19 positive woman presenting to our emergency department (ED) at 34 weeks gestation with preeclampsia. This case highlights the unique diagnostic and therapeutic challenges associated with treating patients with these concomitant diseases.
    MeSH term(s) Adult ; COVID-19/diagnosis ; Female ; Gestational Age ; Humans ; Pre-Eclampsia/diagnosis ; Pre-Eclampsia/virology ; Pregnancy ; Pregnancy Complications, Infectious/diagnosis ; Pregnancy Complications, Infectious/virology ; Radiography, Thoracic ; Tomography, X-Ray Computed
    Keywords covid19
    Language English
    Publishing date 2020-06-25
    Publishing country United States
    Document type Case Reports
    ZDB-ID 605890-5
    ISSN 1532-8171 ; 0735-6757
    ISSN (online) 1532-8171
    ISSN 0735-6757
    DOI 10.1016/j.ajem.2020.06.052
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article ; Online: Progression or Not - A Small Natural History Study of Genetical Confirmed Congenital Myopathies.

    Werlauff, Ulla / Hansen, Pernille Diemer / Witting, Nanna / Vissing, John

    Journal of neuromuscular diseases

    2021  Volume 8, Issue 4, Page(s) 647–655

    Abstract: ... genetically diagnosed patients studied by us in 2010 (n = 41) were invited to the follow-up study; assessment ...

    Abstract Background: Clinical characteristics of patients with congenital myopathies (CM) are well known but there is a lack of knowledge about the natural history and course of disease of the different genetic subtypes. In 2010 we assessed the national cohort of Danish patients with CM to decide genetic diagnosing and describe genotype- phenotype relationships.AIM of this follow-up study was to evaluate the course of disease since the initial study and to evaluate the applicability of standard assessment methods to reflect change over time and patients own opinion on the course of disease.
    Methods: All available genetically diagnosed patients studied by us in 2010 (n = 41) were invited to the follow-up study; assessment of motor function (MFM-32), muscle strength (MRC %)and respiratory function (FVC %) and prime assessor were the same as in the initial study. Patients were asked whether the course of disease had progresses, was stable or had improved.
    Results: 23 patients (15-61 y) accepted the invitation. Mean follow-up time was 7.7 years. Loss of muscle strength was more prominent in patients with mutations in DNM2, RYR1 and TPM2/3 genes and deterioration in FVC % was more evident in patients carrying NEB and ACTA1 gene mutations. MFM-sum score was less sensitive to change compared to MRC-sum score. In general, agreement between the patient's own opinion of the course of disease and results of assessments was good.
    Conclusion: The number of patients in the study is too small to be conclusive, but the results indicate that CM can be stable or slowly progressive depending on the genetic subtype.
    MeSH term(s) Adolescent ; Adult ; Cohort Studies ; Disease Progression ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Muscle Proteins/genetics ; Mutation ; Myopathies, Structural, Congenital/genetics ; Phenotype ; Young Adult
    Chemical Substances Muscle Proteins
    Language English
    Publishing date 2021-03-01
    Publishing country Netherlands
    Document type Journal Article
    ISSN 2214-3602
    ISSN (online) 2214-3602
    DOI 10.3233/JND-200574
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article ; Online: Element abundance patterns in stars indicate fission of nuclei heavier than uranium.

    Roederer, Ian U / Vassh, Nicole / Holmbeck, Erika M / Mumpower, Matthew R / Surman, Rebecca / Cowan, John J / Beers, Timothy C / Ezzeddine, Rana / Frebel, Anna / Hansen, Terese T / Placco, Vinicius M / Sakari, Charli M

    Science (New York, N.Y.)

    2023  Volume 382, Issue 6675, Page(s) 1177–1180

    Abstract: The heaviest chemical elements are naturally produced by the rapid neutron-capture process ( ...

    Abstract The heaviest chemical elements are naturally produced by the rapid neutron-capture process (
    Language English
    Publishing date 2023-12-07
    Publishing country United States
    Document type Journal Article
    ZDB-ID 128410-1
    ISSN 1095-9203 ; 0036-8075
    ISSN (online) 1095-9203
    ISSN 0036-8075
    DOI 10.1126/science.adf1341
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: "High plasma levels of C1-inhibitor are associated with lower risk of future venous thromboembolism": reply.

    Grover, Steven P / Brækkan, Sigrid K / Mackman, Nigel / Hansen, John-Bjarne

    Journal of thrombosis and haemostasis : JTH

    2023  Volume 21, Issue 10, Page(s) 2993–2995

    MeSH term(s) Humans ; Venous Thromboembolism/diagnosis ; Venous Thromboembolism/drug therapy ; Complement C1 Inhibitor Protein
    Chemical Substances Complement C1 Inhibitor Protein
    Language English
    Publishing date 2023-10-26
    Publishing country England
    Document type Letter ; Comment
    ZDB-ID 2112661-6
    ISSN 1538-7836 ; 1538-7933
    ISSN (online) 1538-7836
    ISSN 1538-7933
    DOI 10.1016/j.jtha.2023.07.004
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top