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Manickam Sugumaran, Hanine Barek
Animals synthesize melanin pigments for the coloration of their skin and use it for their protection from harmful solar radiation. Insects use melanins even more ingeniously than mammals and employ them for exoskeletal pigmentation, cuticular hardening, wound healing and innate immune responses. In this review, we discuss the biochemistry of melanogenesis process occurring in higher animals and insects. A special attention is given to number of aspects that are not previously brought to light: (1) the molecular mechanism of dopachrome conversion that leads to the production of two different dihydroxyindoles; (2) the role of catecholamine derivatives other than dopa in melanin production in animals; (3) the critical parts played by various biosynthetic enzymes associated with insect melanogenesis; and (4) the presence of a number of important gaps in both melanogenic and sclerotinogenic pathways...
October 20, 2016: International Journal of Molecular Sciences
Chatchai Muanprasat, Varanuj Chatsudthipong
Chitosan oligosaccharide (COS) is an oligomer of β-(1➔4)-linked D-glucosamine. COS can be prepared from the deacetylation and hydrolysis of chitin, which is commonly found in the exoskeletons of arthropods and insects and the cell walls of fungi. COS is water soluble, non-cytotoxic, readily absorbed through the intestine and mainly excreted in the urine. Of particular importance, COS and its derivatives have been demonstrated to possess several biological activities including anti-inflammation, immunostimulation, anti-tumor, anti-obesity, anti-hypertension, anti-Alzheimer's disease, tissue regeneration promotion, drug and DNA delivery enhancement, anti-microbial, anti-oxidation and calcium-absorption enhancement...
October 20, 2016: Pharmacology & Therapeutics
M G Frías-Espericueta, B Y Ramos-Magaña, J Ruelas-Inzunza, M F Soto-Jiménez, O Escobar-Sánchez, M Aguilar-Juárez, G Izaguirre-Fierro, C C Osuna-Martínez, D Voltolina
We determined total Hg and Se contents of hepatopancreas, exoskeleton, and muscle, and the Se:Hg molar ratios in the muscle of shrimps Farfantepenaeus californiensis and Litopenaeus stylirostris caught in NE Pacific Mexican waters. Total Hg mean values in muscle, hepatopancreas, and exoskeleton were 0.31 ± 0.26, 0.28 ± 0.29, and 0.24 ± 0.06 μg g(-1), and 0.46 ± 0.46, 0.41 ± .034, and 0.24 ± 0.06 μg g(-1) for F. californiensis and L. stylirostris, respectively. In all tissues, the mean concentrations of Se tended to be close to one order of magnitude higher than the respective Hg values...
November 2016: Environmental Monitoring and Assessment
Nina Lefeber, Eva Swinnen, Eric Kerckhofs
PURPOSE: The integration of sufficient cardiovascular stress into robot-assisted gait (RAG) training could combine the benefits of both RAG and aerobic training. The aim was to summarize literature data on the immediate effects of RAG compared to walking without robot-assistance on metabolic-, cardiorespiratory- and fatigue-related parameters. METHODS: PubMed and Web of Science were searched for eligible articles till February 2016. Means, SDs and significance values were extracted...
October 20, 2016: Disability and Rehabilitation. Assistive Technology
Federico Montagnani, Marco Controzzi, Christian Cipriani
The human hand is a complex integrated system with motor and sensory components that provides individuals with high functionality and elegant behaviour. In direct connection with the brain, the hand is capable of performing countless actions ranging from fine digit manipulation to the handling of heavy objects. However the question of which movements mostly contribute to the manipulation skills of the hand, and thus should be included in prosthetic hands, is yet to be answered. Building from our previous work, and assuming that a hand with independent long fingers allowed performance comparable to a hand with coupled fingers, here we explored the actual contribution of independent fingers while performing activities of daily living using custom built orthoses...
October 19, 2016: Scientific Reports
Gelu Onose, Vladimir Cârdei, Ştefan T Crăciunoiu, Valeriu Avramescu, Ioan Opriş, Mikhail A Lebedev, Marian Vladimir Constantinescu
During the last few years, interest has been growing to mechatronic and robotic technologies utilized in wearable powered exoskeletons that assist standing and walking. The available literature includes single-case reports, clinical studies conducted in small groups of subjects, and several recent systematic reviews. These publications have fulfilled promotional and marketing objectives but have not yet resulted in a fully optimized, practical wearable exoskeleton. Here we evaluate the progress and future directions in this field from a joint perspective of health professionals, manufacturers, and consumers...
2016: Frontiers in Neuroscience
Annick Renevey, Sereina Riniker
Polytheonamide B (pTB), a highly cytotoxic peptide produced by a symbiotic bacterium of the marine sponge Theonella swinhoei, forms a transmembrane pore consisting of 49 residues. More than half of its residues are posttranslationally modified. Epimerizations result in alternating L- and D-amino acids that allow the peptide to adopt a [Formula: see text]-helical conformation. Unusually, the wide [Formula: see text]-helix of pTB is stable in a polar environment, which is in contrast to gramicidin A, an antibiotic with similar function and structure...
October 15, 2016: European Biophysics Journal: EBJ
Rony Huys, Eduardo Suárez-Morales, María de Lourdes Serrano-Sánchez, Elena Centeno-García, Francisco J Vega
Copepods are aquatic microcrustaceans and represent the most abundant metazoans on Earth, outnumbering insects and nematode worms. Their position of numerical world predominance can be attributed to three principal radiation events, i.e. their major habitat shift into the marine plankton, the colonization of freshwater and semiterrestrial environments, and the evolution of parasitism. Their variety of life strategies has generated an incredible morphological plasticity and disparity in body form and shape that are arguably unrivalled among the Crustacea...
October 12, 2016: Scientific Reports
Teige C Bourke, Catherine R Lowrey, Sean P Dukelow, Stephen D Bagg, Kathleen E Norman, Stephen H Scott
BACKGROUND: Stroke can affect our ability to perform daily activities, although it can be difficult to identify the underlying functional impairment(s). Recent theories highlight the importance of sensory feedback in selecting future motor actions. This selection process can involve multiple processes to achieve a behavioural goal, including selective attention, feature/object recognition, and movement inhibition. These functions are often impaired after stroke, but existing clinical measures tend to explore these processes in isolation and without time constraints...
October 10, 2016: Journal of Neuroengineering and Rehabilitation
Mi Young Noh, Subbaratnam Muthukrishnan, Karl J Kramer, Yasuyuki Arakane
Adult beetles (Coleoptera) are covered primarily by a hard exoskeleton or cuticle. For example, the beetle elytron is a cuticle-rich highly modified forewing structure that shields the underlying hindwing and dorsal body surface from a variety of harmful environmental factors by acting as an armor plate. The elytron comes in a variety of colors and shapes depending on the coleopteran species. As in many other insect species, the cuticular tanning pathway begins with tyrosine and is responsible for production of a variety of melanin-like and other types of pigments...
October 2016: Current Opinion in Insect Science
Ye Ding, Fausto A Panizzolo, Christopher Siviy, Philippe Malcolm, Ignacio Galiana, Kenneth G Holt, Conor J Walsh
BACKGROUND: Recent advances in wearable robotic devices have demonstrated the ability to reduce the metabolic cost of walking by assisting the ankle joint. To achieve greater gains in the future it will be important to determine optimal actuation parameters and explore the effect of assisting other joints. The aim of the present work is to investigate how the timing of hip extension assistance affects the positive mechanical power delivered by an exosuit and its effect on biological joint power and metabolic cost during loaded walking...
October 3, 2016: Journal of Neuroengineering and Rehabilitation
Rui-Wen Zong, Ruo-Ying Fan, Yi-Ming Gong
A nautiloid conch containing many disarticulated exoskeletons of Omegops cornelius (Phacopidae, Trilobita) was found in the Upper Devonian Hongguleleng Formation of the northwestern margin of the Junggar Basin, NW China. The similar number of cephala, thoraces and pygidia, unbroken thoraces, explicit exuviae, and lack of other macrofossils in the conch, indicate that at least seven individual trilobites had moulted within the nautiloid living chamber, using the vacant chamber of a dead nautiloid as a communal place for ecdysis...
October 5, 2016: Scientific Reports
Carlos F C João, Coro Echeverria, Alexandre Velhinho, Jorge C Silva, Maria H Godinho, João P Borges
Inspired by chitin based hierarchical structures observed in arthropods exoskeleton, this work reports the capturing of chitin nanowhiskers' chiral nematic order into a chitosan matrix. For this purpose, highly crystalline chitin nanowhiskers (CTNW) with spindle-like morphology and average aspect ratio of 24.9 were produced by acid hydrolysis of chitin. CTNW were uniformly dispersed at different concentrations in aqueous suspensions. The suspensions liquid crystalline phase domain was determined by rheological measurements and polarized optical microscopy (POM)...
January 2, 2017: Carbohydrate Polymers
Lesley A Ballantyne, Christine L Lambkin, Xin Luan, Yuvarin Boontop, Sorasak Nak-Eiam, Suttisan Pimpasalee, Sommyot Silalom, Anchana Thancharoen
Sclerotia Ballantyne gen. nov. is established for seven species. Sclerotia aquatilis (Thancharoen, 2007), Scl. brahmina (Bourgeois, 1890), Scl. carinata (Gorham, 1880), Scl. flavida (Hope, 1845), Scl. seriata (Olivier, 1891), and Scl. substriata (Gorham, 1880) are transferred from Luciola Laporte. Sclerotia fui sp. nov. from China is described as new. Luciola cingulata Olivier, 1885 is synonymised with Luciola substriata Gorham. Luciola formosana Pic, 1916 is removed from synonymy with Luciola substriata and newly synonymised with Luciola flavida (Hope)...
September 23, 2016: Zootaxa
Du-Xin Liu, Xinyu Wu, Wenbin Du, Can Wang, Tiantian Xu
Gait phase is widely used for gait trajectory generation, gait control and gait evaluation on lower-limb exoskeletons. So far, a variety of methods have been developed to identify the gait phase for lower-limb exoskeletons. Angular sensors on lower-limb exoskeletons are essential for joint closed-loop controlling; however, other types of sensors, such as plantar pressure, attitude or inertial measurement unit, are not indispensable.Therefore, to make full use of existing sensors, we propose a novel gait phase recognition method for lower-limb exoskeletons using only joint angular sensors...
2016: Sensors
Furui Wang, Christopher L Jones, Milind Shastri, Kai Qian, Derek G Kamper, Nilanjan Sarkar
Chronic hand impairment is common following stroke. This paper presents an actuated thumb exoskeleton (ATX) to facilitate research in examining motor control and hand rehabilitation. The ATX presented in this work aims to provide independent bi-directional actuation in each of the 5 degrees-of-freedom (DOF) of the thumb using a novel flexible shaft based mechanism that has 5 active DOF and 3 passive DOF. A prototype has been built and experiments have been conducted to measure the allowable workspace at the thumb and evaluate the kinematic and kinetic performance of the ATX...
2016: Advanced Robotics: the International Journal of the Robotics Society of Japan
Atsuko Nishimoto, Yohei Otaka, Shoko Kasuga, Eri Otaka, Kotaro Yamazaki, Junichi Ushiba, Meigen Liu
Robotics is an emerging field in rehabilitation medicine. Robots have the potential to complement traditional clinical assessments because they can measure functions more precisely and quantitatively than current clinical assessments. We present a patient with a proximal humeral fracture whose recovery process was evaluated with an exoskeleton robotic device. The patient, a 34-year-old woman, suffered a left proximal humeral fracture while snowboarding. She is an occupational therapist and is the first author of this study...
2016: Keio Journal of Medicine
Guillermo Robles, José Manuel Fresno, Romano Giannetti
The design and optimization of protective equipment and devices such as exoskeletons and prosthetics have the potential to be enhanced by the ability of accurately measure the positions of the bones during movement. Existing technologies allow a quite precise measurement of motion-mainly by using coordinate video-cameras and skin-mounted markers-but fail in directly measuring the bone position. Alternative approaches, as fluoroscopy, are too invasive and not usable during extended lapses of time, either for cost or radiation exposure...
September 22, 2016: ISA Transactions
M Attias, A Bonnefoy-Mazure, G De Coulon, L Cheze, S Armand
Contracture is a permanent shortening of the muscle-tendon-ligament complex that limits joint mobility. Contracture is involved in many diseases (cerebral palsy, stroke, etc.) and can impair walking and other activities of daily living. The purpose of this study was to quantify the reliability of an exoskeleton designed to emulate lower limb muscle contractures unilaterally and bilaterally during walking. An exoskeleton was built according to the following design criteria: adjustable to different morphologies; respect of the principal lines of muscular actions; placement of reflective markers on anatomical landmarks; and the ability to replicate the contractures of eight muscles of the lower limb unilaterally and bilaterally (psoas, rectus femoris, hamstring, hip adductors, gastrocnemius, soleus, tibialis posterior, and peroneus)...
September 19, 2016: Gait & Posture
M Daniela Biaggio, Iara Sandomirsky, Yael Lubin, Ally R Harari, Maydianne C B Andrade
Copulatory cannibalism of male 'widow' spiders (genus Latrodectus) is a model example of the extreme effects of sexual selection, particularly in L. hasselti and L. geometricus where males typically facilitate cannibalism by females and mate only once. We show that these males can increase their reproductive success by copulating with final-instar, immature females after piercing the female's exoskeleton to access her newly developed sperm storage organs. Females retain sperm through their final moult and have similar fecundity to adult-mated females...
September 2016: Biology Letters
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