346 research outputs found

    A mesh-parameter continuation method

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    A mesh-parameter continuation method

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    Nuclear Resonance Vibrational Spectroscopy of Iron Sulfur Proteins

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    Nuclear inelastic scattering in conjunction with density functional theory (DFT) calculations has been applied for the identification of vibrational modes of the high-spin ferric and the high-spin ferrous iron-sulfur center of a rubredoxin-type protein from the thermophylic bacterium Pyrococcus abysii

    Predictors for failure of supraglottic superimposed high-frequency jet ventilation during endoscopic upper airway surgery in pediatric patients

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    Airway surgery in pediatric patients is challenging with regard to balancing surgical exposure with ventilation requirements, as during the procedure the airway must be shared between laryngologist and anesthetist. For endoscopic laryngeal surgery, different methods of ventilation are used, among others jet ventilation via a specifically adapted suspension laryngoscope using a dual jet stream(Supraglottic Superimposed High Frequency Jet ventilation, SSHFJV) (1).High BMI and a history of pulmonary pathology proved to be factors contributing to failing of SSHFJV in adult patients (2). However, factors influencing the failure of SSHFJV in pediatric patients have never been described yet

    Dynamics of Metal Centers Monitored by Nuclear Inelastic Scattering

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    Nuclear inelastic scattering of synchrotron radiation has been used now since 10 years as a tool for vibrational spectroscopy. This method has turned out especially useful in case of large molecules that contain a M\"ossbauer active metal center. Recent applications to iron-sulfur proteins, to iron(II) spin crossover complexes and to tin-DNA complexes are discussed. Special emphasis is given to the combination of nuclear inelastic scattering and density functional calculations

    Virtual 3D planning of tracheostomy placement and clinical applicability of 3D cannula design:A three-step study

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    AIM: We aimed to investigate the potential of 3D virtual planning of tracheostomy tube placement and 3D cannula design to prevent tracheostomy complications due to inadequate cannula position. MATERIALS AND METHODS: 3D models of commercially available cannula were positioned in 3D models of the airway. In study (1), a cohort that underwent tracheostomy between 2013 and 2015 was selected (n = 26). The cannula was virtually placed in the airway in the pre-operative CT scan and its position was compared to the cannula position on post-operative CT scans. In study (2), a cohort with neuromuscular disease (n = 14) was analyzed. Virtual cannula placing was performed in CT scans and tested if problems could be anticipated. Finally (3), for a patient with Duchenne muscular dystrophy and complications of conventional tracheostomy cannula, a patient-specific cannula was 3D designed, fabricated, and placed. RESULTS: (1) The 3D planned and post-operative tracheostomy position differed significantly. (2) Three groups of patients were identified: (A) normal anatomy; (B) abnormal anatomy, commercially available cannula fits; and (C) abnormal anatomy, custom-made cannula, may be necessary. (3) The position of the custom-designed cannula was optimal and the trachea healed. CONCLUSIONS: Virtual planning of the tracheostomy did not correlate with actual cannula position. Identifying patients with abnormal airway anatomy in whom commercially available cannula cannot be optimally positioned is advantageous. Patient-specific cannula design based on 3D virtualization of the airway was beneficial in a patient with abnormal airway anatomy

    Differences in the diagnostic value between fiberoptic and high definition laryngoscopy for the characterisation of pharyngeal and laryngeal lesions:A multi-observer paired analysis of videos

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    Objectives High definition laryngoscopy (HDL) could lead to better interpretation of the pharyngeal and laryngeal mucosa than regularly used fiberoptic laryngoscopy (FOL). The primary aim of this study is to quantify the diagnostic advantage of HDL over FOL in detecting mucosal anomalies in general, in differentiating malignant from benign lesions and in predicting specific histological entities. The secondary aim is to analyse image quality of both laryngoscopes. Design Retrospective paired analysis with multiple observers evaluating endoscopic videos simulating daily clinical practice. Setting A tertiary referral hospital. Participants In 36 patients, both FOL and HDL videos were obtained. Six observers were provided with additional clinical information, and 36 FOL and HDL videos were evaluated in a randomised order. Main outcome measures Sensitivity, specificity, positive and negative predictive value and diagnostic accuracy of observers using both flexible laryngoscopes were calculated for detection of mucosal lesions in general and uncovering malignant lesions. Sensitivities were calculated for prediction of specific histological entities. Image quality (scale 1-10) was assessed for both flexible laryngoscopes. Results HDL reached higher sensitivity compared to FOL for detection of mucosal abnormalities in general (96.0% vs 90.4%; P = .03), differentiating malignant from benign lesions (91.7% vs 79.8%; P = .03) and prediction of specific histological entities (59.7% vs 47.2%; P <.01). Image quality was judged better with HDL in comparison with FOL (mean: 8.4 vs 5.4, P <.01). Conclusions HDL is superior to FOL in detecting mucosal anomalies in general, malignancies and specific histological entities. Image quality is considered as superior using HDL compared to FOL

    High-definition videolaryngoscopy is superior to fiberoptic laryngoscopy:a 111 multi-observer study

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    PURPOSE: This study aims to analyse differences in fiberoptic laryngoscopy (FOL) versus high definition laryngoscopy (HDL) by examining videolaryngoscopy images by a large group of observers with different levels of clinical expertise in ear, nose and throat (ENT) medicine. METHODS: This study is a 111 observer paired analysis of laryngoscopy videos during an interactive presentation. During a National Meeting of the Dutch Society of ENT/Head and Neck Surgery, observers assessed both FOL and HDL videos of nine cases with additional clinical information. Observers included 41 ENT consultants (36.9%), 34 ENT residents (30.6%), 22 researchers with Head and Neck interest (19.8%) and 14 with unspecified clinical expertise (12.6%). For both laryngoscopic techniques, sensitivity, specificity, positive and negative predictive value and diagnostic accuracy were determined for identifying a normal glottis, hyperkeratosis, radiotherapy adverse effects and squamous cell carcinoma. The sensitivities for FOL and HDL were analysed with regard to the different levels of clinical expertise. RESULTS: The overall sensitivity for correctly identifying the specific histological entity was higher in HDL (FOL 61% vs HDL 66.3%, p < 0.05). HDL was superior to FOL in identifying a normal glottis (FOL 68.1% vs HDL 91.6%, p < 0.01) and squamous cell carcinoma (FOL 70.86% vs HDL 79.41%, p = 0.02). Residents and researchers with Head and Neck interest diagnosed laryngeal lesions more correctly with HDL (p < 0.05). CONCLUSIONS: In a large population of observers with different levels of clinical expertise, HDL is superior to FOL in identifying laryngeal lesions

    PTEN Is Associated With Worse Local Control in Early Stage Supraglottic Laryngeal Cancer Treated With Radiotherapy

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    Objectives: The aim of this study was to establish the prognostic value of the epidermal growth factor receptor (EGFR) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression on local control in patients with early stage supraglottic laryngeal squamous cell carcinoma (LSCC) treated with radiotherapy only. Study design: Retrospective cohort study. Methods: Immunohistochemical staining for EGFR and PTEN was performed on pretreatment biopsies of a selected well-defined homogeneous group of 52 patients with T1-T2 supraglottic LSCC treated with radiotherapy between 1990 and 2008. Kaplan-Meier analysis and univariate and multivariate Cox Regression analyses were performed to correlate clinical data and expression levels of EGFR and PTEN with local control. Results: Kaplan-Meier survival analysis and Cox Regression analysis showed a significant association between PTEN expression and local control (hazard ratio [HR] = 3.26, 95% confidence interval [CI] = 1.14-9.33, P = .027) and between lymph node status and local control (HR = 3.60, 95% CI = 1.26-10.31, P = .017). Both were independent prognostic factors in a multivariate analysis (HR = 3.28, 95% CI = 1.14-9.39, P = .027 and HR = 3.62, 95% CI = 1.26-10.37, P = .017, respectively). There was no significant association between EGFR expression and local control (HR = 1.32, 95% CI = 1.17-10.14, P = .79). Conclusion: This study showed an association between both high PTEN expression and the presence of lymph node metastasis and deteriorated local control in early stage supraglottic LSCC treated with radiotherapy. Level of Evidence: NA

    The risk of febrile neutropenia in patients with non-small-cell lung cancer treated with docetaxel: a systematic review and meta-analysis

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    We aimed to assess the incidence of febrile neutropenia in patients with non small cell lung cancer treated with docetaxel as second line chemotherapy by systematic review and meta-analysis of clinical studies. Published studies were retrieved and included if they considered docetaxel at the licensed dose after a previous chemotherapy regimen, and reported the proportion of patients getting FN. Meta-analysis was conducted to estimate the proportion of patients who experience one or more episodes of FN. The pooled, random effects meta-analysis estimate for the proportion of patients who experience one or more episodes of FN on docetaxel was 5.95% (95% CI 4.22–8.31) based on 13 studies, comprising 1609 patients. No significant differences were seen either between studies that permitted the use of prophylactic granulocyte colony-stimulating factors or between phase II and phase III trials
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