Upper Limb Kinematics of Handwriting among Children with and without Developmental Coordination Disorder.

Background: Children with developmental coordination disorder (DCD) often experience difficulties with handwriting legibility and speed. This study investigates the relationship between handwriting and upper limb kinematics to characterize movement patterns of children with DCD and typically developing (TD) children. Methods: 30 children with and without DCD matched for age, gender, and parent education were compared across handwriting abilities using a standardized handwriting assessment of both copied and dictated tasks (A-A Handwriting).

Force chains in cell-cell mechanical communication.

Force chains (FCs) are a key determinant of the micromechanical properties and behaviour of heterogeneous materials, such as granular systems. However, less is known about FCs in fibrous materials, such as the networks composing the extracellular matrix (ECM) of biological systems. Using a finite-element computational model, we simulated the contraction of a single cell and two nearby cells embedded in two-dimensional fibrous elastic networks and analysed the tensile FCs that developed in the ECM.

The correlation between upper extremity musculoskeletal symptoms and joint kinematics, playing habits and hand span during playing among piano students.

Objective: We aimed to investigate the correlations between Upper Extremity Musculoskeletal Symptoms (MSD) and joint kinematics while playing the piano, as well as correlations between MSD and psychosocial, professional and personal habits, and bio-demographic risk factors of piano students.

Method: This cross-sectional study included 15 piano students. The research tools included 3D motion capture, anthropometric measurements, and questionnaires for obtaining data about MSD, psychological, and personal factors.

Pressure distributions on the chair seat and backrest correlate with handwriting outcomes of school children.

Background: Postures while sitting are believed to have an important influence on the process of writing and quality of handwriting, but data in this field are sparse.

Objectives: The current study was undertaken to investigate correlations between 'ordinary' children's handwriting skills and their posture and stability while sitting.

Methods: Twenty-nine children with typical development (age 9.

Nonlinear Elasticity of the ECM Fibers Facilitates Efficient Intercellular Communication.

Biological cells embedded in fibrous matrices have been observed to form intercellular bands of dense and aligned fibers through which they mechanically interact over long distances. Such matrix-mediated cellular interactions have been shown to regulate various biological processes. This study aimed to explore the effects of elastic nonlinearity of the fibers contained in the extracellular matrix (ECM) on the transmission of mechanical loads between contracting cells.

The infrapatellar fat pad is a dynamic and mobile structure, which deforms during knee motion, and has proximal extensions which wrap around the patella.

Purpose: The infrapatellar fat pad (IFP) is a common cause of knee pain and loss of knee flexion and extension. However, its anatomy and behavior are not consistently defined.

Methods: Thirty-six unpaired fresh frozen knees (median age 34 years, range 21-68) were dissected, and IFP attachments and volume measured.

Total ankle replacement design and positioning affect implant-bone micromotion and bone strains.

Implant loosening - commonly linked with elevated initial micromotion - is the primary indication for total ankle replacement (TAR) revision. Finite element modelling has not been used to assess micromotion of TAR implants; additionally, the biomechanical consequences of TAR malpositioning - previously linked with higher failure rates - remain unexplored. The aim of this study was to estimate implant-bone micromotion and peri-implant bone strains for optimally positioned and malpositioned TAR prostheses, and thereby identify fixation features and malpositioning scenarios increasing the risk of loosening.

The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint.

Data about a muscle's fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area.

The effect of compressive deformations on the rate of build-up of oxygen in isolated skeletal muscle cells.

In this study we integrated between confocal-based cell-specific finite element (FE) modeling and Virtual Cell (VC) transport simulations in order to determine trends of relationship between externally applied compressive deformations and build-up rates of oxygen in myoblast cells, and to further test how mild culture temperature drops (~3°C) might affect such trends. Geometries of two different cells were used, and each FE cell model was computationally subjected to large compressive deformations. Build-up of oxygen concentrations within the deformed cell shapes over time were calculated using the VC software.

The influence of foot posture, support stiffness, heel pad loading and tissue mechanical properties on biomechanical factors associated with a risk of heel ulceration.

Heel ulcers (HU) are the second most common type of pressure ulcers. In this work, we developed the first anatomically-realistic three-dimensional finite element model of the posterior heel for studying the risk for HU in bedridden patients. We specifically simulated a heel that is resting on supports with different stiffnesses at upright and inclined foot postures.

Effects of intramuscular fat infiltration, scarring, and spasticity on the risk for sitting-acquired deep tissue injury in spinal cord injury patients.

Sitting-acquired deep tissue injury (DTI) is a severe form of pressure ulcer (PU) often affecting patients with spinal cord injury (SCI) who also tend to suffer from intramuscular fat infiltration, soft tissue scarring (due to previous PU), and/or muscle spasticity in their buttocks. We previously used finite element (FE) modeling to evaluate whether abnormal bodyweight is a risk factor for sitting-acquired DTI. Here we hypothesize that fat infiltration, scarring, or spasms increase internal loads in the gluteus muscles in the vicinity of the ischial tuberosities during sitting, which consequently put SCI patients with these conditions at a higher risk for DTI.

Effects of skin wrinkles, age and wetness on mechanical loads in the stratum corneum as related to skin lesions.

Finite element models of skin were developed to determine the effects of wetness, age, and wrinkles on mechanical strains and stresses in the stratum corneum (SC) as related to skin lesions. We modeled two geometries, young (0.12-mm-deep wrinkles) and aged (0.

Quantitative monitoring of lipid accumulation over time in cultured adipocytes as function of culture conditions: toward controlled adipose tissue engineering.

Adipose tissue engineering is investigated for native fat substitutes and wound healing model systems. Research and clinical applications of bioartificial fat require a quantitative and objective method to continuously measure adipogenesis in living cultures as opposed to currently used culture-destructive techniques that stain lipid droplet (LD) accumulation. To allow standardization, automatic quantification of LD size is further needed, but currently LD size is measured mostly manually.

Fluorescently labeled 1 nm thin nanomembranes.

Fluorescent labeling of self-assembled monolayers (SAMs) has a great potential for chemical and biotechnological sensing. However, its use is limited by the quenching of the fluorescence in the proximity of the conducting substrates. We show that this quenching can be overcome by the labeling of a cross-linked aromatic SAM (nanosheet) and its subsequent transfer onto a non-conducting substrate.

Exposure to internal muscle tissue loads under the ischial tuberosities during sitting is elevated at abnormally high or low body mass indices.

Deep tissue injury (DTI) is a severe pressure ulcer characteristic of chairfast or bedfast individuals, such as those with impaired mobility or neurological disorders. A DTI differs from superficial pressure ulcers in that the onset of DTI occurs under intact skin, in skeletal muscle tissue overlying bony prominences, and progression of the wound continues subcutaneously until skin breakdown. Due to the nature of this silently progressing wound, it is highly important to screen potentially susceptible individuals for their risk of developing a DTI.