Biomechanics analysis of human lower limb during walking for exoskeleton design

Human body experiences a long natural evolution to have good movement forms and flexible driving mode, during which process, human muscles have already evolved to a sophisticated bio-actuator, usually used in the bionic design of mechanical structures. The article presents a novel idea for the bionics design of artificial limb or exoskeleton robot, considering the motion level and the driving level of human body simultaneously, i.e. the lower limb segment movement and the muscle activity. Firstly, as the support phase, the most complex process during human walking, we divided it into three sub-phases and studied each other’s variations about the angle and torque by the built motion capture system, which is important for ground reaction force control (GRF control). Secondly, the principal muscles around the knee joint were studied by biomechanical simulation, i.e. the vastus medialis muscle and the biceps femoris muscle, after the data of clinical gait by experiment was imported into the human simulation software. The result showed that the vastus medialis muscle, as Hill three elements model, was the principal muscle during knee’s extension motion, which mainly worked during the support phase and could provide a maximum force of 280 N.m. In contrast, the biceps femoris muscle, as Hill two elements model, was the principal muscle during knee’s flexion motion, which mainly worked during the swing phase and could provide a maximum force of 220 N.m

Quantitative determinations and imaging in different structures of buried human bones from the XVIII-XIXth centuries by energy dispersive X-ray fluorescence - Postmortem evaluation

In this work, a non-commercial triaxial geometry energy dispersive X-ray Fluorescence (EDXRF) setup and a benchtop mu-XRF system were used to identify postmortem contamination in buried bones. For two of the individuals, unusually high concentrations of Cu and Pb, but also Zn (in one individual) were observed. The pigments of the burial shroud coverings have been identified as the source of contamination.Accurate and precise quantitative results were obtained by nondestructive process using fundamental parameters method taking into account the matrix absorption effects.A total of 30 bones from 13 individuals, buried between the mid-XVlllth to early XIXth centuries, were analyzed to study the elemental composition and elemental distribution. The bones were collected from a church in Almada (Portugal), called Ermida do Espirito Santo, located near the Tagus River and at the sea neighbourhood.The triaxial geometry setup was used to quantify Ca, Fe, Cu, Zn, Br, Sr and Pb of powder pressed bone pellets (n=9 for each bone). Cluster analysis was performed considering the elemental concentrations for the different bones. There was a clear association between some bones regarding Fe, Cu, Zn, Br and Pb content but not a categorization between cortical and trabecular bones. The elemental distribution of Cu, Zn and Pb were assessed by the benchtop p.-analysis, the M4 Tornado, based on a polycapillary system which provides multi-elemental 2D maps. The results showed that contamination was mostly on the surface of the bone confirming that it was related to the burial shroud covering the individuals

Extended depth of field imaging for high speed object analysis

A high speed, high-resolution flow imaging system is modified to achieve extended depth of field imaging. An optical distortion element is introduced into the flow imaging system. Light from an object, such as a cell, is distorted by the distortion element, such that a point spread function (PSF) of the imaging system is invariant across an extended depth of field. The distorted light is spectrally dispersed, and the dispersed light is used to simultaneously generate a plurality of images. The images are detected, and image processing is used to enhance the detected images by compensating for the distortion, to achieve extended depth of field images of the object. The post image processing preferably involves de-convolution, and requires knowledge of the PSF of the imaging system, as modified by the optical distortion element

Imaging and 3D reconstruction of membrane protein complexes by cryo-electron microscopy and single particle analysis

Cryo-electron microscopy (cryo-EM) in combination with single particle image processing and volume reconstruction is a powerful technology to obtain medium-resolution structures of large protein complexes, which are extremely difficult to crystallize and not amenable to NMR studies due to size limitation. Depending on the stability and stiffness as well as on the symmetry of the complex, three-dimensional reconstructions at a resolution of 10-30 ˚ can be achieved. In this range of resolution, we may not be able to answer A chemical questions at the level of atomic interactions, but we can gain detailed insight into the macromolecular architecture of large multi-subunit complexes and their mechanisms of action. In this thesis, several prevalently large membrane protein complexes of great physiological importance were examined by various electron microscopy techniques and single particle image analysis. The core part of my work consists in the imaging of a mammalian V-ATPase, frozen-hydrated in amorphous ice and of the completion of the first volume reconstruction of this type of enzyme, derived from cryo-EM images. This ubiquitous rotary motor is essential in every eukaryotic cell and is of high medical importance due to its implication in various diseases such as osteoporosis, skeletal cancer and kidney disorders. My contribution to the second and third paper concerns the volume reconstruction of two bacterial outer membrane pore complexes from cryo-EM images recorded by my colleague Mohamed Chami. PulD from Klebsiella oxytoca constitutes a massive translocating pore capable of transporting a fully folded cell surface protein PulA through the membrane. It is part of the Type II secretion system, which is common for Gram-negative bacteria. The second volume regards ClyA, a pore-forming heamolytic toxin of virulent Escherichia coli and Salmonella enterica strains that kill target cells by inserting pores into their membranes. To the last two papers, I contributed with cryo-negative stain imaging of the cell division protein DivIVA from Bacillus subtilis and with image processing of the micrographs displaying the siderophore receptor FrpB from Neisseria meningitidis

A Survey on Deep Learning in Medical Image Analysis

Deep learning algorithms, in particular convolutional networks, have rapidly become a methodology of choice for analyzing medical images. This paper reviews the major deep learning concepts pertinent to medical image analysis and summarizes over 300 contributions to the field, most of which appeared in the last year. We survey the use of deep learning for image classification, object detection, segmentation, registration, and other tasks and provide concise overviews of studies per application area. Open challenges and directions for future research are discussed.Comment: Revised survey includes expanded discussion section and reworked introductory section on common deep architectures. Added missed papers from before Feb 1st 201

The protective effects of the antioxidant combination of ferulic acid with vitamins C and E against UV-induced photodamage in human skin cells

Includes abstract.Includes bibliographical references (leaves 91-122).This study assessed the ability of 0.8 mM ferulic acid (FA), in combination with vitamins C and E, to reduce the effect of UVA-induced photodamage in human epidermal (HaCaTs) and dermal skin cells (primary human fibroblasts (HFbs) and murine 3T3 cells). Pretreatment with the FA and vitamins C and E (vEC) combination solution reduced UVAinduced ROS in human fibroblasts while pre-treatment with vEC individually led to a reduction in HaCaTs

Histopathological image analysis : a review

Over the past decade, dramatic increases in computational power and improvement in image analysis algorithms have allowed the development of powerful computer-assisted analytical approaches to radiological data. With the recent advent of whole slide digital scanners, tissue histopathology slides can now be digitized and stored in digital image form. Consequently, digitized tissue histopathology has now become amenable to the application of computerized image analysis and machine learning techniques. Analogous to the role of computer-assisted diagnosis (CAD) algorithms in medical imaging to complement the opinion of a radiologist, CAD algorithms have begun to be developed for disease detection, diagnosis, and prognosis prediction to complement the opinion of the pathologist. In this paper, we review the recent state of the art CAD technology for digitized histopathology. This paper also briefly describes the development and application of novel image analysis technology for a few specific histopathology related problems being pursued in the United States and Europe

Genetic regulation of pituitary gland development in human and mouse

Normal hypothalamopituitary development is closely related to that of the forebrain and is dependent upon a complex genetic cascade of transcription factors and signaling molecules that may be either intrinsic or extrinsic to the developing Rathke’s pouch. These factors dictate organ commitment, cell differentiation, and cell proliferation within the anterior pituitary. Abnormalities in these processes are associated with congenital hypopituitarism, a spectrum of disorders that includes syndromic disorders such as septo-optic dysplasia, combined pituitary hormone deficiencies, and isolated hormone deficiencies, of which the commonest is GH deficiency. The highly variable clinical phenotypes can now in part be explained due to research performed over the last 20 yr, based mainly on naturally occurring and transgenic animal models. Mutations in genes encoding both signaling molecules and transcription factors have been implicated in the etiology of hypopituitarism, with or without other syndromic features, in mice and humans. To date, mutations in known genes account for a small proportion of cases of hypopituitarism in humans. However, these mutations have led to a greater understanding of the genetic interactions that lead to normal pituitary development. This review attempts to describe the complexity of pituitary development in the rodent, with particular emphasis on those factors that, when mutated, are associated with hypopituitarism in humans

Aluminum and Phthalates in Calcium Gluconate: Contribution from Glass and Plastic Packaging

Introduction: Aluminum contamination of parenteral nutrition solutions has been documented for three decades. It can result in elevated blood, bone, and whole body aluminum levels associated with neurotoxicity, reduced bone mass and mineral content, and perhaps hepatotoxicity. The primary aluminum source among parenteral nutrition components is glass-packaged calcium gluconate, in which aluminum concentration the past three decades has averaged~ 4000 [mu]g/L, compared to \u3c 200 [mu]g/L in plastic container-packaged calcium gluconate. A concern about plastic packaging is leaching of plasticizers, including phthalates, which have the potential to cause endocrine (male reproductive system) disruption and neurotoxicity. Methods: Aluminum was quantified in samples collected periodically over more than two years from three calcium gluconate sources used to prepare parenteral nutrition solutions; two packaged in glass (from France and the US) and one in plastic (from Germany); in a recently released plastic-packaged solution (from the US);and in the two glass containers. Phthalate concentration was determined in selected samples of each product and leachate of the plastic containers. Results: The initial aluminum concentration was ~ 5000 [mu]g/L in the two glass-packaged products and ~ 20 [mu]g/L in the plastic-packaged product, and increased ~ 30, 50 and 100% over 2 years, respectively. The aluminum concentration in a recently released Calcium Gluconate Injection USP was ~ 320 [mu]g/L. Phthalates were not detected in any calcium gluconate solutions or leachates. Conclusion: Plastic packaging greatly reduces the contribution of aluminum to parenteral nutrition solutions from calcium gluconate compared to the glass-packaged product