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1.
J Endocrinol Invest ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38724880

RESUMO

PURPOSE: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease characterized by persistent fatigue and decreased daily activity following physical and/or cognitive exertion. While ME/CFS affects both sexes, there is a higher prevalence in women. However, studies evaluating this sex-related bias are limited. METHODS: Circulating steroid hormones, including mineralocorticoids (aldosterone), glucocorticoids (cortisol, corticosterone, 11-deoxycortisol, cortisone), androgens (androstenedione, testosterone), and progestins (progesterone, 17α-hydroxyprogesterone), were measured in plasma samples using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Samples were obtained from mild/moderate (ME/CFSmm; females, n=20; males, n=8), severely affected patients (ME/CFSsa; females, n=24; males, n=6), and healthy controls (HC, females, n=12; males, n=17). RESULTS: After correction for multiple testing, we observed that circulating levels of 11-deoxycortisol, 17α-hydroxyprogesterone in females, and progesterone in males were significantly different between HC, ME/CFSmm, and ME/CFSsa. Comparing two independent groups, we found that female ME/CFSsa had higher levels of 11-deoxycortisol (vs. HC and ME/CFSmm) and 17α-hydroxyprogesterone (vs. HC). In addition, female ME/CFSmm showed a significant increase in progesterone levels compared to HC. In contrast, our study found that male ME/CFSmm had lower circulating levels of cortisol and corticosterone, while progesterone levels were elevated compared to HC. In addition to these univariate analyses, our correlational and multivariate approaches identified differential associations between our study groups. Also, using two-component partial least squares discriminant analysis (PLS-DA), we were able to discriminate ME/CFS from HC with an accuracy of 0.712 and 0.846 for females and males, respectively. CONCLUSION: Our findings suggest the potential value of including steroid hormones in future studies aimed at improving stratification in ME/CFS. Additionally, our results provide new perspectives to explore the clinical relevance of these differences within specific patient subgroups.

2.
Wien Klin Wochenschr ; 136(Suppl 5): 103-123, 2024 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-38743348

RESUMO

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe, chronic multisystemic disease which, depending on its severity, can lead to considerable physical and cognitive impairment, loss of ability to work and the need for nursing care including artificial nutrition and, in very severe cases, even death.The aim of this D-A-CH (Germany, Austria, Switzerland) consensus statement is 1) to summarize the current state of knowledge on ME/CFS, 2) to highlight the Canadian Consensus Criteria (CCC) as clinical criteria for diagnostics with a focus on the leading symptom post-exertional malaise (PEM) and 3) to provide an overview of current options and possible future developments, particularly with regard to diagnostics and therapy. The D-A-CH consensus statement is intended to support physicians, therapists and valuer in diagnosing patients with suspected ME/CFS by means of adequate anamnesis and clinical-physical examinations as well as the recommended clinical CCC, using the questionnaires and other examination methods presented. The overview of the two pillars of therapy for ME/CFS, pacing and symptom-relieving therapy options, is intended not only to provide orientation for physicians and therapists, but also to support decision-makers from healthcare policy and insurance companies in determining which therapy options should already be reimbursable by them at this point in time for the indication ME/CFS.


Assuntos
Síndrome de Fadiga Crônica , Síndrome de Fadiga Crônica/terapia , Síndrome de Fadiga Crônica/diagnóstico , Humanos , Áustria , Alemanha , Suíça , Colaboração Intersetorial , Guias de Prática Clínica como Assunto , Equipe de Assistência ao Paciente
4.
J Clin Med ; 13(1)2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38202282

RESUMO

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex disease characterized by profound fatigue, post-exertional malaise (PEM), and neurocognitive dysfunction. Immune dysregulation and gastrointestinal symptoms are commonly observed in ME/CFS patients. Despite affecting approximately 0.89% of the general population, the underlying pathophysiological mechanisms remain poorly understood. This study aimed to elucidate the relationship between immunological characteristics and intestinal barrier function in ME/CFS patients. ME/CFS patients were stratified into two groups based on their immune competence. After documentation of detailed medical records, serum and plasma samples were collected for the assessment of inflammatory immune mediators and biomarkers for intestinal barrier integrity by ELISA. We found reduced complement protein C4a levels in immunodeficient ME/CFS patients suggesting a subgroup-specific innate immune dysregulation. ME/CFS patients without immunodeficiencies exhibit a mucosal barrier leakage, as indicated by elevated levels of Lipopolysaccharide-binding protein (LBP). Stratifying ME/CFS patients based on immune competence enabled the distinction of two subgroups with different pathophysiological patterns. The study highlights the importance of emphasizing precise patient stratification in ME/CFS, particularly in the context of defining suitable treatment strategies. Given the substantial health and socioeconomic burden associated with ME/CFS, urgent attention and research efforts are needed to define causative treatment approaches.

5.
Autoimmun Rev ; 22(11): 103452, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37742748

RESUMO

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a devastating disease affecting millions of people worldwide. Due to the 2019 pandemic of coronavirus disease (COVID-19), we are facing a significant increase of ME/CFS prevalence. On May 11th to 12th, 2023, the second international ME/CFS conference of the Charité Fatigue Center was held in Berlin, Germany, focusing on pathomechanisms, diagnosis, and treatment. During the two-day conference, more than 100 researchers from various research fields met on-site and over 700 attendees participated online to discuss the state of the art and novel findings in this field. Key topics from the conference included: the role of the immune system, dysfunction of endothelial and autonomic nervous system, and viral reactivation. Furthermore, there were presentations on innovative diagnostic measures and assessments for this complex disease, cutting-edge treatment approaches, and clinical studies. Despite the increased public attention due to the COVID-19 pandemic, the subsequent rise of Long COVID-19 cases, and the rise of funding opportunities to unravel the pathomechanisms underlying ME/CFS, this severe disease remains highly underresearched. Future adequately funded research efforts are needed to further explore the disease etiology and to identify diagnostic markers and targeted therapies.


Assuntos
Síndrome de Fadiga Crônica , Humanos , Síndrome de Fadiga Crônica/diagnóstico , Síndrome de Fadiga Crônica/epidemiologia , Síndrome de Fadiga Crônica/terapia , Pandemias , Síndrome de COVID-19 Pós-Aguda , Prevalência
6.
Healthcare (Basel) ; 11(15)2023 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-37570426

RESUMO

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe chronic illness and patients with ME/CFS are often medically underserved in Germany and other countries. One contributing factor is health professionals' lack of knowledge about epidemiology, diagnostic criteria, and treatment of ME/CFS. Opportunities are scarce for health professionals to receive continuing medical education on ME/CFS. The current research addressed this need for further education and investigated the gain of knowledge from a webinar for German-speaking health professionals. In two studies (total sample: N = 378), participants in the intervention condition completed a knowledge test twice (before and after webinar participation). Study 2 also included a waiting-list control condition with repeated response to the knowledge test without webinar participation between measurements. Results showed that at baseline, most participants had seen patients with ME/CFS, but confidence in diagnosing and treating ME/CFS was only moderate-to-low. In the intervention condition, but not in the control condition, knowledge about ME/CFS increased between the first and the second knowledge test. These results indicate that the webinar was successful in increasing health professionals' knowledge about ME/CFS. We concluded that webinars can be a cost-efficient and effective tool in providing health professionals with large-scale continuing medical education about ME/CFS.

8.
Medicina (Kaunas) ; 59(4)2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-37109676

RESUMO

Myalgic encephalomyelitis/chronic fatigue (ME/CFS) is a post-infectious, chronic disease that can lead to severe impairment and, even, total disability. Although the disease has been known for a long time, and has been coded in the ICD since 1969 (G93.3), medical research has not yet been able to reach a consensus regarding its physiological basis and how best to treat it. Against the background of these shortcomings, psychosomatic disease models have been developed and psychotherapeutic treatments have been derived from them, but their empirical testing has led to sobering results. According to the current state of research, psychotherapy and psychosomatic rehabilitation have no curative effect in the treatment of ME/CFS. Nevertheless, we see numerous patients in practices and outpatient clinics who suffer severely as a result of their illness and whose mental well-being and coping strategies would benefit from psychotherapeutic help. In this article, we outline a psychotherapeutic approach that serves this need, taking into account two basic characteristics of ME/CFS: firstly, the fact that ME/CFS is a physical illness and that curative treatment must therefore be physical; and secondly, the fact that post exertional malaise (PEM) is a cardinal symptom of ME/CFS and thus warrants tailored psychotherapeutic attention.


Assuntos
Síndrome de Fadiga Crônica , Humanos , Síndrome de Fadiga Crônica/terapia , Psicoterapia
10.
J Colloid Interface Sci ; 607(Pt 1): 698-710, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34530190

RESUMO

Anisotropic nanoparticles offer considerable promise for applications but also present significant challenges in terms of their characterization. Recent developments in the electroless deposition of silver patches directly onto colloidal silica particles have opened up a simple and scalable synthesis method for patchy particles with tunable optical properties. Due to the reliance on patch nucleation and growth, however, the resulting coatings are distributed in coverage and thickness and some core particles remain uncoated. To support process optimization, new methods are required to rapidly determine patch yield, thickness and coverage. Here we present a novel approach based on multiwavelength analytical ultracentrifugation (MWL-AUC) which permits simultaneous hydrodynamic and spectroscopic characterization. The patchy particle colloids are produced in a continuous flow mixing process that makes use of a KM-type micromixer. By varying the process flow rate or metal precursor concentration we show how the silver to silica mass ratio distribution derived from the AUC-measured sedimentation coefficient distribution can be influenced. Moreover, through reasoned assumptions we arrive at an estimation of the patch yield that is close to that determined by arduous analysis of scanning electron microscopy (SEM) images. Finally, combining MWL-AUC, electrodynamic simulations and SEM image analysis we establish a procedure to estimate the patch thickness and coverage.


Assuntos
Nanopartículas , Prata , Coloides , Dióxido de Silício , Ultracentrifugação
11.
Biomolecules ; 11(9)2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34572574

RESUMO

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe multi-systemic disease characterized by debilitating fatigue that is not relieved by rest. The causes of the disease are still largely unexplained, and no causative treatment is currently available. Changes in the immune response are considered as fundamental in the development of ME/CFS. Thus, we aimed to evaluate the immunological profile of ME/CFS patients in a retrospective data analysis. As part of the routine workup for ME/CFS patients, a differential blood count, leukocyte subtyping, and quantification of immunoglobulins and IgG subclasses, as well as a complement analysis, was performed. Out of 262 ME/CFS patients, 64.9% had a reduction or deficiency in at least one of the listed immune parameters. In contrast, 26.3% showed signs of immune activation or inflammation. A total of 17.6% of the ME/CFS patients had an unclassified antibody deficiency, with IgG3 and IgG4 subclass deficiencies as the most common phenotypes. Reduced MBL (mannose-binding lectin) levels were found in 32% of ME/CFS patients, and MBL deficiency in 7%. In summary, the present results confirmed the relevance of immune dysfunction in ME/CFS patients underlining the involvement of a dysfunctional immune response in the disease. Thus, immune parameters are relevant disease biomarkers, which might lead to targeted therapeutic approaches in the future.


Assuntos
Síndrome de Fadiga Crônica/imunologia , Adolescente , Adulto , Idoso , Áustria , Estudos de Coortes , Síndrome de Fadiga Crônica/diagnóstico , Feminino , Humanos , Imunidade Celular , Imunidade Humoral , Masculino , Pessoa de Meia-Idade , Adulto Jovem
12.
PLoS One ; 14(4): e0215168, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31009488

RESUMO

In laryngeal high-speed videoendoscopy (HSV) the area between the vibrating vocal folds during phonation is of interest, being referred to as glottal area waveform (GAW). Varying camera resolution may influence parameters computed on the GAW and hence hinder the comparability between examinations. This study investigates the influence of spatial camera resolution on quantitative vocal fold vibratory function parameters obtained from the GAW. In total 40 HSV recordings during sustained phonation (20 healthy males and 20 healthy females) were investigated. A clinically used Photron Fastcam MC2 camera with a frame rate of 4000 fps and a spatial resolution of 512×256 pixels was applied. This initial resolution was reduced by pixel averaging to (1) a resolution of 256×128 and (2) to a resolution of 128×64 pixels, yielding three sets of recordings. The GAW was extracted and in total 50 vocal fold vibratory parameters representing different features of the GAW were computed. Statistical analyses using SPSS Statistics, version 21, was performed. 15 Parameters showing strong mathematical dependencies with other parameters were excluded from the main analysis but are given in the Supporting Information. Data analysis revealed clear influence of spatial resolution on GAW parameters. Fundamental period measures and period perturbation measures were the least affected. Amplitude perturbation measures and mechanical measures were most strongly influenced. Most glottal dynamic characteristics and symmetry measures deviated significantly. Most energy perturbation measures changed significantly in males but were mostly unaffected in females. In females 18 of 35 remaining parameters (51%) and in males 22 parameters (63%) changed significantly between spatial resolutions. This work represents the first step in studying the impact of video resolution on quantitative HSV parameters. Clear influences of spatial camera resolution on computed parameters were found. The study results suggest avoiding the use of the most strongly affected parameters. Further, the use of cameras with high resolution is recommended to analyze GAW measures in HSV data.


Assuntos
Laringoscopia/métodos , Laringe/fisiologia , Gravação em Vídeo/métodos , Prega Vocal/fisiologia , Adolescente , Adulto , Feminino , Glote/fisiologia , Humanos , Masculino , Fonação , Vibração , Qualidade da Voz , Adulto Jovem
13.
J Voice ; 33(5): 811.e1-811.e12, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29861291

RESUMO

OBJECTIVE: The phonatory process is often judged during sustained phonation by analyzing the acoustic voice signal and the vocal fold vibrations. Many formulas and parameters have been suggested for qualifying the characteristics of the acoustic signal and the vocal fold vibrations during sustained phonation. These parameters are directly computed from the acoustic signal and the endoscopic glottal area waveform (GAW). The GAW is calculated from laryngeal high-speed videoendoscopy (HSV) recordings and describes the increase and decrease of the glottal area during the phonation process, that is, the opening and closing of the two oscillating vocal folds over time. However, some of the parameters have strong mathematical dependencies with one another and some are ill-defined. The purpose of this study is to identify mathematical dependencies between parameters with the aim of reducing their numbers and suggesting which parameters may best describe the properties of the GAW and the acoustical signal. METHODS: In this preliminary investigation, 20 frequently used parameters are examined: 10 GAW only and 10 both GAW and acoustic parameters. RESULTS: In total 13 parameters can be neglected because of mathematical dependencies. In addition, nine of these parameters show problematic features that range from unexpected behavior to ill definition. CONCLUSIONS: Reducing the number of parameters appears to be necessary to standardize vocal fold function analysis. This may lead to better comparability of research results from different studies.


Assuntos
Acústica , Glote/diagnóstico por imagem , Laringoscopia , Modelos Teóricos , Fonação , Processamento de Sinais Assistido por Computador , Gravação em Vídeo , Qualidade da Voz , Glote/fisiologia , Humanos , Valor Preditivo dos Testes , Fatores de Tempo , Vibração
14.
Nat Commun ; 9(1): 4898, 2018 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-30464237

RESUMO

Properties of nanoparticles are influenced by various parameters like size, shape or composition. Comprehensive high throughput characterization techniques are urgently needed to improve synthesis, scale up to production and make way for new applications of multidimensional particulate systems. In this study, we present a method for measuring two-dimensional size distributions of plasmonic nanorods in a single experiment. Analytical ultracentrifuge equipped with a multiwavelength extinction detector is used to record the optical and sedimentation properties of gold nanorods simultaneously. A combination of sedimentation and extinction properties, both depending on diameter and length of the dispersed nanorods, is used to measure two-dimensional distributions of gold nanorod samples. The length, diameter, aspect ratio, volume, surface and cross-sectional distributions can be readily obtained from these results. As the technique can be extended to other non-spherical plasmonic particles and can be used for determining relative amounts of particles of different shapes it provides complete and quantitative insights into particulate systems.

15.
Materials (Basel) ; 10(10)2017 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-28937643

RESUMO

We present a novel approach for gradient based maximization of phononic band gaps. The approach is a geometry projection method combining parametric shape optimization with density based topology optimization. By this approach, we obtain, in a two dimension setting, cellular structures exhibiting relative and normalized band gaps of more than 8 and 1.6, respectively. The controlling parameter is the minimal strut size, which also corresponds with the obtained stiffness of the structure. The resulting design principle is manually interpreted into a three dimensional structure from which cellular metal samples are fabricated by selective electron beam melting. Frequency response diagrams experimentally verify the numerically determined phononic band gaps of the structures. The resulting structures have band gaps down to the audible frequency range, qualifying the structures for an application in noise isolation.

16.
Clin Lab ; 61(1-2): 93-100, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25807643

RESUMO

BACKGROUND: Increased markers of systemic inflammation had been found in patients with acute heart failure. These and other findings led to the hypothesis of an increased rate of bacterial translocation in severe or acute heart failure, leading to systemic inflammation. The present study examined if bacterial translocation occurs under physiological conditions in rats and if its rate and spectrum changes in chronic compensated ischemic heart failure. METHODS: Myocardial infarction (MI) was induced by proximal ligation of the left anterior descending coronary artery or a sham operation was performed. Rats were followed up for six months and mesenteric lymph nodes of the surviving animals with large MI were excised and bacterial translocation was quantified by cultivating viable bacteria. RESULTS: Induction of a large MI led to a significant cardiac remodelling, elevated levels of atrial natriuretic peptide, and pulmonary oedema. There was no difference in the spectrum or in the rate of bacterial translocation compared with controls, neither comparing all cultured bacteria nor predefined subgroups (e.g., intestinal bacteria). CONCLUSIONS: Bacterial translocation is a physiological process with no gradual increase in chronic compensated heart failure in rats.


Assuntos
Translocação Bacteriana , Insuficiência Cardíaca/microbiologia , Mucosa Intestinal/fisiopatologia , Isquemia Miocárdica/microbiologia , Animais , Quimiocina CCL2/sangue , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/fisiopatologia , Interleucina-6/sangue , Masculino , Isquemia Miocárdica/sangue , Isquemia Miocárdica/fisiopatologia , Distribuição Aleatória , Ratos Endogâmicos Lew , Remodelação Ventricular
17.
J Acoust Soc Am ; 134(2): 1261-70, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23927124

RESUMO

Commonly applied models to study vocal fold vibrations in combination with air flow distributions are self-sustained physical models of the larynx consisting of artificial silicone vocal folds. Choosing appropriate mechanical parameters and layer geometries for these vocal fold models while considering simplifications due to manufacturing restrictions is difficult but crucial for achieving realistic behavior. In earlier work by Schmidt et al. [J. Acoust. Soc. Am. 129, 2168-2180 (2011)], the authors presented an approach in which material parameters of a static numerical vocal fold model were optimized to achieve an agreement of the displacement field with data retrieved from hemilarynx experiments. This method is now generalized to a fully transient setting. Moreover in addition to the material parameters, the extended approach is capable of finding optimized layer geometries. Depending on chosen material restriction, significant modifications of the reference geometry are predicted. The additional flexibility in the design space leads to a significantly more realistic deformation behavior. At the same time, the predicted biomechanical and geometrical results are still feasible for manufacturing physical vocal fold models consisting of several silicone layers. As a consequence, the proposed combined experimental and numerical method is suited to guide the construction of physical vocal fold models.


Assuntos
Modelos Anatômicos , Fonação , Silicones , Prega Vocal/anatomia & histologia , Prega Vocal/fisiologia , Idoso , Fenômenos Biomecânicos , Simulação por Computador , Módulo de Elasticidade , Humanos , Masculino , Análise Numérica Assistida por Computador , Reologia , Vibração
18.
J Acoust Soc Am ; 130(2): 948-64, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21877808

RESUMO

With the use of an endoscopic, high-speed camera, vocal fold dynamics may be observed clinically during phonation. However, observation and subjective judgment alone may be insufficient for clinical diagnosis and documentation of improved vocal function, especially when the laryngeal disease lacks any clear morphological presentation. In this study, biomechanical parameters of the vocal folds are computed by adjusting the corresponding parameters of a three-dimensional model until the dynamics of both systems are similar. First, a mathematical optimization method is presented. Next, model parameters (such as pressure, tension and masses) are adjusted to reproduce vocal fold dynamics, and the deduced parameters are physiologically interpreted. Various combinations of global and local optimization techniques are attempted. Evaluation of the optimization procedure is performed using 50 synthetically generated data sets. The results show sufficient reliability, including 0.07 normalized error, 96% correlation, and 91% accuracy. The technique is also demonstrated on data from human hemilarynx experiments, in which a low normalized error (0.16) and high correlation (84%) values were achieved. In the future, this technique may be applied to clinical high-speed images, yielding objective measures with which to document improved vocal function of patients with voice disorders.


Assuntos
Simulação por Computador , Modelos Biológicos , Fonação , Prega Vocal/fisiologia , Voz , Algoritmos , Fenômenos Biomecânicos , Feminino , Humanos , Laringoscopia , Masculino , Pressão , Reprodutibilidade dos Testes , Vibração , Gravação em Vídeo , Prega Vocal/anatomia & histologia
19.
Adv Mater ; 23(22-23): 2669-74, 2011 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-21823262

RESUMO

It appears that most models for micro-structured materials with auxetic deformations were found by clever intuition, possibly combined with optimization tools, rather than by systematic searches of existing structure archives. Here we review our recent approach of finding micro-structured materials with auxetic mechanisms within the vast repositories of planar tessellations. This approach has produced two previously unknown auxetic mechanisms, which have Poisson's ratio νss=-1 when realized as a skeletal structure of stiff incompressible struts pivoting freely at common vertices. One of these, baptized Triangle-Square Wheels, has been produced as a linear-elastic cellular structure from Ti-6Al-4V alloy by selective electron beam melting. Its linear-elastic properties were measured by tensile experiments and yield an effective Poisson's ratio νLE≈-0.75, also in agreement with finite element modeling. The similarity between the Poisson's ratios νSS of the skeletal structure and νLE of the linear-elastic cellular structure emphasizes the fundamental role of geometry for deformation behavior, regardless of the mechanical details of the system. The approach of exploiting structure archives as candidate geometries for auxetic materials also applies to spatial networks and tessellations and can aid the quest for inherently three-dimensional auxetic mechanisms.


Assuntos
Manufaturas/análise , Ligas/química , Elasticidade , Modelos Moleculares , Estresse Mecânico , Titânio/química
20.
J Acoust Soc Am ; 129(4): 2168-80, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21476672

RESUMO

Today, the prevention and treatment of voice disorders is an ever-increasing health concern. Since many occupations rely on verbal communication, vocal health is necessary just to maintain one's livelihood. Commonly applied models to study vocal fold vibrations and air flow distributions are self sustained physical models of the larynx composed of artificial silicone vocal folds. Choosing appropriate mechanical parameters for these vocal fold models while considering simplifications due to manufacturing restrictions is difficult but crucial for achieving realistic behavior. In the present work, a combination of experimental and numerical approaches to compute material parameters for synthetic vocal fold models is presented. The material parameters are derived from deformation behaviors of excised human larynges. The resulting deformations are used as reference displacements for a tracking functional to be optimized. Material optimization was applied to three-dimensional vocal fold models based on isotropic and transverse-isotropic material laws, considering both a layered model with homogeneous material properties on each layer and an inhomogeneous model. The best results exhibited a transversal-isotropic inhomogeneous (i.e., not producible) model. For the homogeneous model (three layers), the transversal-isotropic material parameters were also computed for each layer yielding deformations similar to the measured human vocal fold deformations.


Assuntos
Modelos Biológicos , Fonética , Distúrbios da Fala/patologia , Distúrbios da Fala/fisiopatologia , Prega Vocal/fisiologia , Movimentos do Ar , Humanos , Neoplasias Laríngeas/patologia , Neoplasias Laríngeas/fisiopatologia
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