805 research outputs found
A Muscle Model Based on Feldman's Lambda Model: 3D Finite Element Implementation
This paper presents the introduction of Feldman's muscle model in a three
dimensional continuum finite element model of the human face. This model is
compared to the classical Hill-type muscle modelComment: CMBBE'2013, Salt Lake City : United States (2013
Hermite-Hadamard type inequalities for operator geometrically convex functions
In this paper, we introduce the concept of operator geometrically convex
functions for positive linear operators and prove some Hermite-Hadamard type
inequalities for these functions. As applications, we obtain trace inequalities
for operators which give some refinements of previous results.Comment: Accepted for publishing in Monatshefte fur Mathemati
The Distributed Lambda Model (DLM): A 3-D, Finite-Element Muscle Model Based on Feldman's Lambda Model; Assessment of Orofacial Gestures
International audiencePurpose: The authors aimed to design a distributed Lambda model (DLM), which is well-adapted to implement three-dimensional (3-D) Finite Element descriptions of muscles. Method: A muscle element model was designed. Its stress-strain relationships included the active force-length characteristics of the Lambda model along the muscle fibers, together with the passive properties of muscle tissues in the 3-D space. The muscle element was first assessed using simple geometrical representations of muscles in form of rectangular bars. Then, it was included in a 3-D face model, and its impact on lip protrusion was compared with the impact of a Hill-type muscle model. Results: The force-length characteristic associated with the muscle elements matched well with the invariant characteristics of the Lambda model. The impact of the passive properties was assessed. Isometric force variation and isotonic displacements were modeled. The comparison with a Hill-type model revealed strong similarities in terms of global stress and strain. Conclusion: The DLM accounted for the characteristics of the Lambda model. Biomechanically no clear differences were found between the DLM and a Hill-type model. Accurate evaluations of the Lambda model, based on the comparison between data and simulations, are now possible with 3-D biomechanical descriptions of the speech articulators because to the DLM
Face
The face is probably the part of the body, which most distinguishes us as individuals. It plays a very important role in many functions, such as speech, mastication, and expression of emotion. In the face, there is a tight coupling between different complex structures, such as skin, fat, muscle, and bone. Biomechanically driven models of the face provide an opportunity to gain insight into how these different facial components interact. The benefits of this insight are manifold, including improved maxillofacial surgical planning, better understanding of speech mechanics, and more realistic facial animations. This chapter provides an overview of facial anatomy followed by a review of previous computational models of the face. These models include facial tissue constitutive relationships, facial muscle models, and finite element models. We also detail our efforts to develop novel general and subject-specific models. We present key results from simulations that highlight the realism of the face models
Standardization of a trauma symptoms checklist for children
Background: The aim of this study was to standardize and assign validity and reliability of the Trauma Symptom Checklist for Children (TSCC-A). Methods: Normative data for the TSCC-A were based on 3042 students participating in a prevalence child abuse study in 19 different locations of Tehran and 140 participants who had been refered to the run-away children centers in Tehran. After the TSCC was validated on run-away and abused children, it was made available to researchers doing larger studies on a normative group. Results: Reliability analysis of the TSCC-A scales in the normative sample demonstrated high internal consistency. The evidence for its validations (convergent, discriminant and construct validity) showed that they were significantly acceptable. Conclusion: This paper presents data demonstrating the psychometric reliability and validity of the TSCC-A scales in the Iranian student population. We suggest to include the TSCC-A in a battery of relevant standardized tests
Finite element modelling of nearly incompressible materials and volumetric locking: a case study
International audienceThe purpose of this paper is to illustrate the influence of the choice of the finite element technology on the occurrence of locking and hourglass instabilities. We chose to focus on the case study of the activation of the posterior genio-glossus (GGp) that is a lingual muscle located at the root of the tongue and inserts in the front to the mandible. The activation of this muscle compresses the tongue in the lower part and generates a forward and upward movement of the tongue body, because of the incompressibility of tongue tissues (for example during the production of the phonemes /i/ or /s/)
Abnormalities of Motor Imagery and Relationship With Depressive Symptoms in Mildly Disabling Relapsing-Remitting Multiple Sclerosis
The effectiveness of motor imagery (MI)
as an adjunct to physical rehabilitation has previously been shown.
Motor imagery ability can be affected by neurologic disorders that
affect motor and cognitive function. This study was designed to assess MI ability in persons with mildly disabling relapsing-remitting
multiple sclerosis (RRMS) based on the functional and cognitive
dysfunctions.
Methods: Twenty-two participants with RRMS and 23 age-, gender-,
and education-matched comparison subjects were evaluated by a battery of MI tasks, including a kinesthetic and visual imagery questionnaire, a mental hand rotation task, and a visual guided pointing
task.
Results: There was no significant difference in MI vividness between
the participants with MS and the comparison group, but the accuracy
and temporal correspondence of MI in the participants with MS differed significantly from those in the comparison group. Depression
scores were significantly higher in participants with MS (P < 0.001),
and depression was significantly correlated with disability (r = 0.4;
P < 0.05). The correlation between accuracy of MI in the participants
with MS and their cognitive ability was significant (r = 0.57; P <
0.05). The MI duration of participants with MS was significantly correlated with their disability (r = 0.59; P < 0.05) and their cognitive
ability (r = −0.38; P = 0.009).
Discussion: The preservation of MI ability was observed in participants with RRMS; however, abnormalities in accuracy and temporal
aspects of MI were observed even in the participants with mild disease. Abnormalities in temporal aspects and accuracy of MI were
related to disability and cognitive ability, respectively. In participants
with MS, depression should be considered as a confounding factor
for the MI task results. Conclusions: Our finding could be considered in the application of
MI during the rehabilitation of persons with MS
Strategic Planning of Livestock: A Commercial Soft Technology Based on the Supply Chain Strategy in Golestan Provinance
The aim of this study is strategic planning of poultry cluster to determine the leverage points based on the supply chain strategy and to offer approaches according to commercial soft technology maturity. The study was performed using field study and documentation between September 2017 and August 2018. The results highlight the leverage points regarding supply and demand management of chicken meat with an emphasis on export market and low maturity of business technology in Golestan poultry markets. Some solutions are presented with regard to the current situation of the markets which are basically based on business soft technology.
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