Structural and wetting properties of nature\u27s finest silks (order Embioptera)

Insects from the order Embioptera (webspinners) spin silk fibres which are less than 200 nm in diameter. In this work, we characterized and compared the diameters of single silk fibres from nine species—Antipaluria urichi, Pararhagadochir trinitatis, Saussurembia calypso, Diradius vandykei, Aposthonia ceylonica, Haploembia solieri, H. tarsalis, Oligotoma nigra and O. saundersii. Silk from seven of these species have not been previously quantified. Our studies cover five of the 10 named taxonomic families and represent about one third of the known taxonomic family-level diversity in the order Embioptera. Naturally spun silk varied in diameter from 43.6 ± 1.7 nm for D. vandykei to 122.4 ± 3.2 nm for An. urichi. Mean fibre diameter did not correlate with adult female body length. Fibre diameter is more similar in closely related species than in more distantly related species. Field observations indicated that silk appears shiny and smooth when exposed to rainwater. We therefore measured contact angles to learn more about interactions between silk and water. Higher contact angles were measured for silks with wider fibre diameter and higher quantity of hydrophobic amino acids. High static contact angles (ranging up to 122° ± 3° for An. urichi) indicated that silken sheets spun by four arboreal, webspinner species were hydrophobic. A second contact angle measurement made on a previously wetted patch of silk resulted in a lower contact angle (average difference was greater than 27°) for all four species. Our studies suggest that silk fibres which had been previously exposed to water exhibited irreversible changes in hydrophobicity and water adhesion properties. Our results are in alignment with the ‘super-pinning’ site hypothesis by Yarger and co-workers to describe the hydrophobic, yet water adhesive, properties exhibited by webspinner silk fibres. The physical and chemical insights gained here may inform the synthesis and development of smaller diameter silk fibres with unique water adhesion properties

Spatial distribution of local currents of massless Dirac fermions in quantum transport through graphene nanoribbons

We employ the formalism of bond currents, expressed in terms of the nonequilibrium Green functions, to image the charge flow between two sites of the honeycomb lattice of graphene ribbons of few nanometers width. In sharp contrast to nonrelativistic electrons, current density profiles of quantum transport at energies close to the Dirac point in clean zigzag graphene nanoribbons (ZGNR) differs markedly from the profiles of charge density peaked at the edges due to zero-energy localized edge states. For transport through the lowest propagating mode induced by these edge states, edge vacancies do not affect current density peaked in the center of ZGNR. The long-range potential of a single impurity acts to reduce local current around it while concurrently increasing the current density along the zigzag edge, so that ZGNR conductance remains perfect $G=2e^2/h$.Comment: 5 pages, 5 figure

Structural characterization of nanofiber silk produced by embiopterans (webspinners)

Embiopterans produce silken galleries and sheets using exceptionally fine silk fibers in which they live and breed. In this study, we use electron microscopy (EM), Fourier-transform infrared (FT-IR) spectroscopy, wide angle X-ray diffraction (WAXD) and solid-state nuclear magnetic resonance (ssNMR) techniques to elucidate the molecular level protein structure of webspinner (embiid) silks. Silks from two species Antipaluria urichi and Aposthonia ceylonica are studied in this work. Electron microscopy images show that the fibers are about 90–100 nm in diameter, making webspinner silks among the finest of all known animal silks. Structural studies reveal that the silk protein core is dominated by β-sheet structures, and that the protein core is coated with a hydrophobic alkane-rich surface coating. FTIR spectra of native embiid silk shows characteristic alkane CH2 stretchings near 2800–2900 cm−1, which decrease approximately 50% after washing the silk with 2 : 1 CHCl3 : MeOH. Furthermore, 13C ssNMR data shows a significant CH2 resonance that is strongly affected by the presence of water, supporting the idea that the silk fibers are coated with a hydrocarbon-rich layer. Such a layer is likely used to protect the colonies from rain. FTIR data also suggests that embiid silks are dominated by β-sheet secondary structures similar to spider and silkworm silk fibers. NMR data confirms the presence of β-sheet nanostructures dominated by serine-rich repetitive regions. A deconvolution of the serine Cβ NMR resonance reveals that approximately 70% of all seryl residues exist in a β-sheet structure. This is consistent with WAXD results that suggest webspinner silks are 70% crystalline, which is the highest crystalline fraction reported for any animal silks. The work presented here provides a molecular level structural picture of silk fibers produced by webspinners

Shapes, contact angles, and line tensions of droplets on cylinders

Using an interface displacement model we calculate the shapes of nanometer-size liquid droplets on homogeneous cylindrical surfaces. We determine effective contact angles and line tensions, the latter defined as excess free energies per unit length associated with the two contact lines at the ends of the droplet. The dependences of these quantities on the cylinder radius and on the volume of the droplets are analyzed.Comment: 26 pages, RevTeX, 10 Figure

Robotic manipulation for the shoe-packaging process

[EN] This paper presents the integration of a robotic system in a human-centered environment, as it can be found in the shoe manufacturing industry. Fashion footwear is nowadays mainly handcrafted due to the big amount of small production tasks. Therefore, the introduction of intelligent robotic systems in this industry may contribute to automate and improve the manual production steps, such us polishing, cleaning, packaging, and visual inspection. Due to the high complexity of the manual tasks in shoe production, cooperative robotic systems (which can work in collaboration with humans) are required. Thus, the focus of the robot lays on grasping, collision detection, and avoidance, as well as on considering the human intervention to supervise the work being performed. For this research, the robot has been equipped with a Kinect camera and a wrist force/ torque sensor so that it is able to detect human interaction and the dynamic environment in order to modify the robot¿s behavior. To illustrate the applicability of the proposed approach, this work presents the experimental results obtained for two actual platforms, which are located at different research laboratories, that share similarities in their morphology, sensor equipment and actuation system.This work has been partly supported by the Ministerio de Economia y Competitividad of the Spanish Government (Key No.: 0201603139 of Invest in Spain program and Grant No. RTC-2016-5408-6) and by the Deutscher Akademischer Austauschdienst (DAAD) of the German Government (Projekt-ID 54368155).Gracia Calandin, LI.; Perez-Vidal, C.; Mronga, D.; Paco, JD.; Azorin, J.; Gea, JD. (2017). Robotic manipulation for the shoe-packaging process. The International Journal of Advanced Manufacturing Technology. 92(1-4):1053-1067. https://doi.org/10.1007/s00170-017-0212-6S10531067921-4Pedrocchi N, Villagrossi E, Cenati C, Tosatti LM (2017) Design of fuzzy logic controller of industrial robot for roughing the uppers of fashion shoes. Int J Adv Manuf Technol 77(5):939–953Hinojo-Perez JJ, Davia-Aracil M, Jimeno-Morenilla A, Sanchez-Romero L, Salas F (2016) Automation of the shoe last grading process according to international sizing systems. Int J Adv Manuf Technol 85(1):455–467Dura-Gil JV, Ballester-Fernandez A, Cavallaro M, Chiodi A, Ballarino A, von Arnim V., Brondi C, Stellmach D (2016) New technologies for customizing products for people with special necessities: project fashion-able. Int J Comput Integr Manuf. In Press, doi: 10.1080/0951192X.2016.1145803Jatta F, Zanoni L, Fassi I, Negri S (2004) A roughing/cementing robotic cell for custom made shoe manufacture. Int J Comput Integr Manuf 17(7):645–652Nemec B, Zlajpah L (2008) Robotic cell for custom finishing operations. Int J Comput Integr Manuf 21(1):33–42Molfino R, et al (2004) Modular, reconfigurable prehensor for grasping and handling limp materials in the shoe industry. In: IMS international forum, CernobbioIntelishoe - integration and linking of shoe and auxiliary industries. 5Th FPSpecial shoes movement. 7th FP, NMP-2008-SME-2-R.229261, http://www.sshoes.euVilaca JL, Fonseca J (2007) A new software application for footwear industry. In: IEEE international symposium on intelligent signal processing WISP 2007, pp 1–6Custom, environment and comfort made shoe. 6TH FP [2004-2008]Framework of integrated technologies for user centred products. Grant agreement no.: CP-TP 229336-2. NMP2-SE-2009-229336 FIT4U -7TH FPRobofoot project website. http://www.robofoot.eu/ . Accessed 2016/ 09/16Montiel E (2007) Customization in the footwear industry. In: proceedings of the MIT congress on mass customizationSucan I, Kavraki LE (2012) A sampling-based tree planner for systems with complex dynamics, vol 28Kuffner JJ Jr, LaValle SM (2000) Rrt-connect: an efficient approach to single-query path planning. In: Proceedings of the IEEE international conference on robotics and automation, 2000. ICRA ’00, vol 2, pp 995–1001Ratliff N, Zucker M, Andrew Bagnell J, Srinivasa S (2009) Chomp: gradient optimization techniques for efficient motion planning. In: IEEE international conference on robotics and automation, 2009. ICRA ’09, pp 489–494Brock O, Khatib O (1997) Elastic strips: real-time path modification for mobile manipulationKroger T (2011) Opening the door to new sensor-based robot applications #x2014;the reflexxes motion libraries. In: 2011 IEEE international conference on robotics and automation (ICRA), pp 1–4Berg J, Ferguson D, Kuffner J (2006) Anytime path planning and replanning in dynamic environments. In: Proceedings of the IEEE international conference on robotics and automation (ICRA), pp 2366–2371Berenson D, Abbeel P, Goldberg K (2012) A robot path planning framework that learns from experience. In: IEEE international conference on robotics and automation. IEEE, pp 3671–3678Bischoff R, Kurth J, Schreiber G, Koeppe R, Albu-Schaeffer A, Beyer A, Eiberger O, Haddadin S, Stemmer A, Grunwald G, Hirzinger G (2010) The kuka-dlr lightweight robot arm — a new reference platform for robotics research and manufacturing. In: Robotics (ISR), 2010 41st international symposium on and 2010 6th German conference on robotics (ROBOTIK), pp 1–8Rooks B (2006) The harmonious robot. Industrial Robot-an International Journal 33:125–130Vahrenkamp N, Wieland S, Azad P, Gonzalez D, Asfour T, Dillmann R (2008) Visual servoing for humanoid grasping and manipulation tasks. In: 8th IEEE-RAS international conference on humanoid robots, 2008, Humanoids 2008, pp 406–412Pieters RS, et al. (2012) Direct trajectory generation for vision-based obstacle avoidance. In: Proceedings of the 2012 IEEE/RSJ international conference on intelligent robots and systemsKinect for windows sensor components and specifications, website. http://msdn.microsoft.com/en-us/library/jj131033.aspx . Accessed 2016/09/16Jatta F, Zanoni L, Fassi I, Negri S (2004) A roughing cementing robotic cell for custom made shoe manufacture. Int J Comput Integr Manuf 17(7):645–652Maurtua I, Ibarguren A, Tellaeche A (2012) Robotics for the benefit of footwear industry. In: International conference on intelligent robotics and applications. Springer, Berlin, pp 235–244Arkin RC (1998) Behavior-based robotics. MIT PressNilsson NJ (1980) Principles of artificial intelligence. Morgan KaufmannAsada H, Slotine J-JE (1986) Robot analysis and control. WileyROS official web page. http://www.ros.org , (Accessed on 2017/ 02/03)Langmann B, Hartmann K, Loffeld O (2012) Depth camera technology comparison and performance evaluation. In: 1st international conference on pattern recognition applications and methods, pp 438–444The player project. free software tools for robot and sensor applications. http://playerstage.sourceforge.net/ , (Accessed on 2017/ 02/03)Yet another robot platform (YARP). http://www.yarp.it/ , (Accessed on 2017/02/03)The OROCOS project. smarter control in robotics and automation. http://www.orocos.org/ , (Accessed on 2017/02/03)CARMEN: Robot navigation toolkit. http://carmen.sourceforge.net/ , (Accessed on 2017/02/03)ORCA: Components for robotics. http://orca-robotics.sourceforge.net/ , (Accessed on 2017/02/03)MOOS: Mission oriented operating suite. http://www.robots.ox.ac.uk/mobile/MOOS/wiki/pmwiki.php/Main/HomePage , (Accessed on 2017/02/03)Microsoft robotics studio. https://www.microsoft.com/en-us/download/details.aspx?id=29081 , (Accessed on 2017/02/03)Pr2 ros website. http://www.ros.org/wiki/Robots/PR2 . Accessed 2016/09/16Care-o-bot 3 ros website. http://www.ros.org/wiki/Robots/Care-O-bot . Accessed 2016/09/16Aila, mobile dual-arm manipulation, website. http://robotik.dfki-bremen.de/de/forschung/robotersysteme/aila.html . Accessed 2016/09/16Package libpcan documentation, website. http://www.ros.org/wiki/libpcan . Accessed 2016/09/16Pcan driver for linux, user manual. http://www.peak-system.com . Document version 7.1 (2011-03-21)Pcan driver for linux, user manual. http://wiki.ros.org/schunk_powercube_chain . Accessed 2016/09/16Ros nodes documentation, website. http://www.ros.org/wiki/Nodes . Accessed 2016/09/16Ros messages documentation, website. http://www.ros.org/wiki/Messages . Accessed 2016/09/16Ros topics documentation, website. http://www.ros.org/wiki/Topics . Accessed 2016/09/16Ros services documentation, website. http://www.ros.org/wiki/Services . Accessed 2016/09/16Yaml files officials website. http://www.yaml.org/ . Accessed 2016/ 09/16Ros robot model (urdf) documentation website. http://www.ros.org/wiki/urdf . Accessed 2016/09/16Point cloud library (pcl), website. http://www.pointclouds.org/ . Accessed 2016/09/16Arm navigation ros stack, website. http://wiki.ros.org/arm_navigation . Accessed 2016/09/16Hornung A, Wurm KM, Bennewitz M, Stachniss C, Burgard W (2013) Octomap: an efficient probabilistic 3d mapping framework based on octrees Autonomous RobotsOrocos kdl documentation, website. http://www.orocos.org/kdl . Accessed 2016/09/16Ioan A, Şucan MM, Kavraki LE (2012) The open motion planning library, vol 19. http://ompl.kavrakilab.orgWaibel M, Beetz M, Civera J, D’Andrea R, Elfring J, Galvez-Lopez D, Haussermann K, Janssen R, Montiel JMM, Perzylo A, Schiessle B, Tenorth M, Zweigle O, van de Molengraft R (2011) Roboearth. IEEE Robot Autom Mag 18(2):69–82Simox toolbox. http://simox.sourceforge.net/ . Accessed 2016/09/16Moreels P, Perona P (2007) Evaluation of features detectors and descriptors based on 3d objects. Int J Comput Vis 73:263–284Viola P, Jones M (2001) Rapid object detection using a boosted cascade of simple features. In: Proceedings of the IEEE computer society conference on computer vision and pattern recognition, 2001. CVPR 2001, vol 1Teuliere C, Marchand E, Eck L (2010) Using multiple hypothesis in model-based tracking. In: 2010 IEEE international conference on robotics and automation (ICRA), pp 4559–4565Moulianitis VC, Dentsoras AJ, Aspragathos NA (1999) A knowledge-based system for the conceptual design of grippers for handling fabrics. Artif Intell Eng Des Anal Manuf 13(1):13–25Davis S, Tsagarakis NG, Caldwell DG (2008) The initial design and manufacturing process of a low cost hand for the robot icub. In: 8th IEEE-RAS international conference on humanoid robots, pp 40–45Cerruti G, Chablat D, Gouaillier D, Sakka S (2017) Design method for an anthropomorphic hand able to gesture and grasp. In: IEEE international conference on robotics and automation. IEEE, pp 3671–367

11-[3-(Dimethyl­amino)prop­yl]-6,11-dihydro­dibenzo[b,e]thiepin-11-ol

There are two independent mol­ecules (A and B) in the asymmetric unit of the title compound, C19H23NOS. In each mol­ecule, the seven-membered thiepine ring is bent into a slightly twisted V-shape. The dihedral angles between the mean planes of the two benzene rings fused to the thiepine ring are 75.7 (5) in mol­ecule A and 73.8 (4)° in mol­ecule B. In both mol­ecules, an intra­molecular O—H⋯N hydrogen bond occurs. In the crystal, weak inter­molecular C—H⋯O and C—H⋯π-ring inter­actions are observed

Draft genome sequence of the coccolithovirus EhV-84

The Coccolithoviridae is a recently discovered group of viruses that infect the marine coccolithophorid Emiliania huxleyi. Emiliania huxleyi virus 84 (EhV-84) has a 160 -180 nm diameter icosahedral structure and a genome of approximately 400 kbp. Here we describe the structural and genomic features of this virus, together with a near complete draft genome sequence (~99%) and its annotation. This is the fourth genome sequence of a member of the coccolithovirus family

Serum metabolomic profiling in acute alcoholic hepatitis identifies multiple dysregulated pathways

Background and Objectives While animal studies have implicated derangements of global energy homeostasis in the pathogenesis of acute alcoholic hepatitis (AAH), the relevance of these findings to the development of human AAH remains unclear. Using global, unbiased serum metabolomics analysis, we sought to characterize alterations in metabolic pathways associated with severe AAH and identify potential biomarkers for disease prognosis. Methods This prospective, case-control study design included 25 patients with severe AAH and 25 ambulatory patients with alcoholic cirrhosis. Serum samples were collected within 24 hours of the index clinical encounter. Global, unbiased metabolomics profiling was performed. Patients were followed for 180 days after enrollment to determine survival. Results Levels of 234 biochemicals were altered in subjects with severe AAH. Random-forest analysis, principal component analysis, and integrated hierarchical clustering methods demonstrated that metabolomics profiles separated the two cohorts with 100% accuracy. Severe AAH was associated with enhanced triglyceride lipolysis, impaired mitochondrial fatty acid beta oxidation, and upregulated omega oxidation. Low levels of multiple lysolipids and related metabolites suggested decreased plasma membrane remodeling in severe AAH. While most measured bile acids were increased in severe AAH, low deoxycholate and glycodeoxycholate levels indicated intestinal dysbiosis. Several changes in substrate utilization for energy homeostasis were identified in severe AAH, including increased glucose consumption by the pentose phosphate pathway, altered tricarboxylic acid (TCA) cycle activity, and enhanced peptide catabolism. Finally, altered levels of small molecules related to glutathione metabolism and antioxidant vitamin depletion were observed in patients with severe AAH. Univariable logistic regression revealed 15 metabolites associated with 180-day survival in severe AAH. Conclusion Severe AAH is characterized by a distinct metabolic phenotype spanning multiple pathways. Metabolomics profiling revealed a panel of biomarkers for disease prognosis, and future studies are planned to validate these findings in larger cohorts of patients with severe AAH.This study was funded by Grant 5K08AA017622 from the National Institutes of Health and a University of Pittsburgh Medical Center Pilot Grant to JB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript