THEORETICAL MODEL VALIDATION OF MUSCLE FORCES DURING EXTREME MOVEMENTS

Introduction: The validation of the involved muscular forces for a computer model of the human body, which allows simulation of internal forces in patients, was achieved by inverse-dynamic analysis. Methods: Beginning with an extreme vertical jump, joint moments were extracted from high-speed film data and eventually subdivided into muscular forces. The muscle groups responsible for movements were determined by electromyography. A squat jump with both legs and maximum strength was filmed in the sagittal plane with a frequency of 200 Hz. Moments in the hip, knee and ankle joints were determined from the film data. Using surface electrodes of a Neuraxon Myosoft 2008 system and an amplifier system from Multichannel Systems, the muscle groups responsible for movements were electromyographically determined. The muscle insertions and muscle paths were extracted from MRI pictures of patients. Results: With this information joint moments can be subdivided into single muscle forces. Depending on the jump demands, the muscle groups responsible for movements can be divided and analyzed in six extensor groups. Conclusion: Inverse-dynamic muscle force analysis is a basis which can be expanded for the validation of complex movements under extreme internal loads in patients

Origin of the transition entropy in vanadium dioxide

The reversible metal-insulator transition in VO2 at TC = 340 K has been closely scrutinized yet its thermodynamic origin remains ambiguous. We discuss the origin of the transition entropy by calculating the electron and phonon contributions at TC using density functional theory. The vibration frequencies are obtained from harmonic phonon calculations, with the soft modes that are imaginary at zero temperature renormalized to real values at TC using experimental information from diffuse x-ray scattering at high-symmetry wavevectors. Gaussian Process Regression is used to infer the transformed frequencies for wavevectors across the whole Brillouin zone, and in turn compute the finite temperature phonon partition function to predict transition thermodynamics. Using this method, we predict the phase transition in VO2 is driven five to one by phonon entropy over electronic entropy, and predict a total transition entropy that accounts for 95% of the calorimetric value

Synthesis of Fatty Acid-Based Polyesters and Their Blends with Poly(L-lactide) as a Way To Tailor PLLA Toughness

10.1021/sc500648gInternational audiencePolylactide (PLA) is one of the most mature biobased and biocompostable plastics currently in the market. Despite its mechanical properties comparable to the ones of some mainstream petroleum-based thermoplastics (PS, for instance), PLA inherent brittleness and heat sensitivity are issues for its full industrial development. In this study, we investigated the melt-blending of PLLA (poly-L-lactide) with fatty acid-based flexible polyesters as an efficient way to tailor PLLA toughness. To that aim, a set of aliphatic polyesters has been developed by taking benefit of the large range of biobased building blocks that can be obtained from plant oils. Melt-blending of the so-formed polyesters with PLLA resulted in improved properties that can be finely tailored by varying the structure and the properties of the plant-based polyester additives

Evolution and Classification of Myosins, a Paneukaryotic Whole-Genome Approach

notes: PubMed ID: 24443438© The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.Myosins are key components of the eukaryotic cytoskeleton, providing motility for a broad diversity of cargoes. Therefore, understanding the origin and evolutionary history of myosin classes is crucial to address the evolution of eukaryote cell biology. Here, we revise the classification of myosins using an updated taxon sampling that includes newly or recently sequenced genomes and transcriptomes from key taxa. We performed a survey of eukaryotic genomes and phylogenetic analyses of the myosin gene family, reconstructing the myosin toolkit at different key nodes in the eukaryotic tree of life. We also identified the phylogenetic distribution of myosin diversity in terms of number of genes, associated protein domains and number of classes in each taxa. Our analyses show that new classes (i.e., paralogs) and domain architectures were continuously generated throughout eukaryote evolution, with a significant expansion of myosin abundance and domain architectural diversity at the stem of Holozoa, predating the origin of animal multicellularity. Indeed, single-celled holozoans have the most complex myosin complement among eukaryotes, with paralogs of most myosins previously considered animal specific. We recover a dynamic evolutionary history, with several lineage-specific expansions (e.g., the myosin III-like gene family diversification in choanoflagellates), convergence in protein domain architectures (e.g., fungal and animal chitin synthase myosins), and important secondary losses. Overall, our evolutionary scheme demonstrates that the ancestral eukaryote likely had a complex myosin repertoire that included six genes with different protein domain architectures. Finally, we provide an integrative and robust classification, useful for future genomic and functional studies on this crucial eukaryotic gene family.LeverhulmeBBSRCERCMINECONERCGordon and Betty Moore Foundatio

MUSCLE ACTIVITY OF THREE SUBJECTS DIFFERING IN WEIGHT AND HEIGHT DURING A VERTICAL JUMP

Introduction: The first measurement was done to evaluate changes of potentials of surface electromyography with different locations of electrode sites and different resistors between the electrodes. The objective of the second was to investigate the activity of muscles in their stimulation sequence, the quantitative participation of the single muscle and cinematic study of vertical jumps. This work is part of a project to determine the internal forces of the human motional apparatus with an anatomical model of muscles. Methods: For each measurement we chose a Noraxon EMG, ECG electrodes from Medicotest, and the electrodes were placed following the description of D.A. Winter. At first we chose the M. gastro. med., M. gastro. lat., and M. soleus of male subject and did a measurement while the subject moved ten times from a ‘standing at attention’ posture to standing on the tips of his toes with a resistor between the electrodes higher than 60 Ohm and one with a resistor lower than 5 Ohm. Then we moved the electrodes 2 cm and 4 cm in the vertical and horizontal directions (resistor of lower than 5 Ohm). Secondly, we chose eight muscles (M. glut. max., M. semitend., M. biceps femoris, M. rectus femoris, M. vastus lat., M. vastus med., M. gastro. med., M. soleus) of three male subjects differing in weight and height and did the measurements while the subjects jumped ten times from a squatting position on a force plate, filmed by a high-speed camera. Results: The measurements with a 60 Ohm resistor and a 5 Ohm resistor differed, as well as the measurements with different locations of electrode sites. The second measurements showed that the M. gas. med. seemed to be the muscle with the highest response, followed by the M. sol. The M. vast. med., M. vast. lat., M. bic. fem. and M. rec. fem. had the same type of reaction. In one case the M. glut. max. seemed to be important while jumping. In an second case the M. semit. showed a high response. The muscles of the tallest subject had the longest activity, and the muscles of the shortest one had the shortest activity. The timedependent angles of knee, hip and foot joints of every subject were nearly identical. Like the EMG, the acceleration phases of the tallest subject took the longest time, while the acceleration phase of the shortest subject took the least time. Conclusions: Firstly, it is possible to see how important the placement and resistor of the electrodes is. Secondly, there is a possible relationship between the beginning of the activity of the muscles and the size of the subjects, as well as a correlation of the angles and the size of the subjects. This effect should be considered in using such calculations of the internal forces of the human motional apparatus in the development of protheses and in sports science

3D-TV Production from Conventional Cameras for Sports Broadcast

3DTV production of live sports events presents a challenging problem involving conflicting requirements of main- taining broadcast stereo picture quality with practical problems in developing robust systems for cost effective deployment. In this paper we propose an alternative approach to stereo production in sports events using the conventional monocular broadcast cameras for 3D reconstruction of the event and subsequent stereo rendering. This approach has the potential advantage over stereo camera rigs of recovering full scene depth, allowing inter-ocular distance and convergence to be adapted according to the requirements of the target display and enabling stereo coverage from both existing and ‘virtual’ camera positions without additional cameras. A prototype system is presented with results of sports TV production trials for rendering of stereo and free-viewpoint video sequences of soccer and rugby

Electron and phonon interactions and transport in the ultrahigh-temperature ceramic ZrC

We have simulated the ultrahigh-temperature ceramic zirconium carbide (ZrC) in order to predict electron and phonon scattering properties, including lifetimes and transport. Our predictions of heat and charge conductivity, which extend to 3000 K, are relevant to extreme-temperature applications of ZrC. Mechanisms are identified on a first-principles basis that considerably enhance or suppress heat transport at high temperature, including strain, anharmonic phonon renormalization, and four-phonon scattering. The extent to which boundary confinement and isotope scattering effects lower thermal conductivity is predicted

GPU Accelerated Viscous-fluid Deformable Registration for Radiotherapy

In cancer treatment organ and tissue deformation betweenradiotherapy sessions represent a significant challenge to op-timal planning and delivery of radiation doses. Recent de-velopments in image guided radiotherapy has caused a soundrequest for more advanced approaches for image registrationto handle these deformations. Viscous-fluid registration isone such deformable registration method. A drawback withthis method has been that it has required computation timesthat were too long to make the approach clinically appli-cable. With recent advances in programmability of graph-ics hardware, complex user defined calculations can now beperformed on consumer graphics cards (GPUs). This pa-per demonstrates that the GPU can be used to drasticallyreduce the time needed to register two medical 3D imagesusing the viscous-fluid registration method. This facilitatesan increased incorporation of image registration in radio-therapy treatment of cancer patients, potentially leading tomore efficient treatment with less severe side effects

Linking motor-related brain potentials and velocity profiles in multi-joint arm reaching movements

The study of the movement related brain potentials (MRPBs) needs accurate technical approaches to disentangle the specific patterns of bran activity during the preparation and execution of movements. During the last forty years, synchronizing the electromyographic activation (EMG) of the muscle with electrophysiological recordings (EEG) has been commonly ussed for these purposes. However, new clinical approaches in the study of motor diseases and rehabilitation suggest the demand of new paradigms that might go further into the study of the brain activity associated with the kinematics of movements. As a response to this call, we have used a 3-D hand-tracking system with the aim to record continuously the position of an ultrasonic sender attached to the hand during the performance of multi-joint self-paced movements. We synchronized time-series of position and velocity of the sender with the EEG recordings, obtaining specific patterns of brain activity as a function of the fluctuations of the kinematics during natural movement performance. Additionally, the distribution of the brain activity during the preparation and execution phases of movements was similar that reported previously using the EMG, suggesting the validity of our technique. We claim that this paradigm could be usable in patients because of its simplicity and the potential knowledge that can be extracted from clinical protocols