Influence of packing density and surface roughness of vertically-aligned carbon nanotubes on adhesive properties of gecko-inspired mimetics.

We have systematically studied the macroscopic adhesive properties of vertically aligned nanotube arrays with various packing density and roughness. Using a tensile setup in shear and normal adhesion, we find that there exists a maximum packing density for nanotube arrays to have adhesive properties. Too highly packed tubes do not offer intertube space for tube bending and side-wall contact to surfaces, thus exhibiting no adhesive properties. Likewise, we also show that the surface roughness of the arrays strongly influences the adhesion properties and the reusability of the tubes. Increasing the surface roughness of the array strengthens the adhesion in the normal direction, but weakens it in the shear direction. Altogether, these results allow progress toward mimicking the gecko's vertical mobility.The authors acknowledge funding from the EC project Technotubes.This is the accepted manuscript. The final version is available at http://pubs.acs.org/doi/abs/10.1021/am507822b

ОСТРАЯ И ХРОНИЧЕСКАЯ ТОКСИЧНОСТЬ ПРЕПАРАТА НА ОСНОВЕ ЭФИРНОГО МАСЛА ПИХТЫ СИБИРСКОЙ

The authors conducted toxicological and allergic research and explored new specimen Aerosan-P which is based on essential oil of Siberian fir (Abies sibirica L.). The specimen is used for prevention and treatment of respiratory diseases. The research found out that the specimen was safe for laboratory animals and young cattle. The researchers explored acute toxicity on white rats and white mice when they applied the specimen to rats and mice dozed 3000 and 5000 mg/kg. Epidermal acute toxicity of Aerosan-P was investigated on the white rats by means of its epidermal application in 2 variants: 2500 mg/kg (0.5 gpro a rat) and 5000 mg/kg (1 gpro a rat). The data of percutaneous and peroral toxicity received shows that according to the GOST 12.1.007–76. Hazardous substances. Classification and general requirements of safety, the specimen is referred to the 4th hazard category – low-hazard substances. The researchers explored the impact of the specimen on mucous membranes and potential irritation effect when they applied 5 mg of the specimen on the left eye cornea of rabbits whereas the right eye was controlled. The specimen doesn’t have an impact on the rats’ skin and rabbits’ eyes. The authors explored the chronic toxicity of the specimen on the young Black-and-White cattle and applied 1500 and 750 mg/kg of the specimen during 30 days. The animals were controlled during the whole period of experiment. The authors found out that the specimen didn’t influence negatively the young cattle health.Проведенными токсикологическими и аллергическими исследованиями нового препарата на основе эфирного масла пихты сибирской (Abies sibirica L.), предназначенного для профилактики и лечения болезней органов дыхания у животных, – Аэросана–П установлена его безопасность для лабораторных животных и молодняка крупного рогатого скота. Острую токсичность препарата изучали на белых крысах и белых мышах. Вводили его однократно крысам и мышам через рот в дозах 3000 и 5000 мг/кг. Накожную острую токсичность Аэросана-П изучали на белых крысах путем его нанесения на кожу в двух дозах из расчета на1 кгмассы тела: 2500 мг/кг (0,5 гна крысу) и 5000 мг/кг (1 гна крысу). В соответствии с полученными данными перкутанной и пероральной токсичности, согласно ГОСТ 12.1.007–76. Вредные вещества. Классификация и общие требования безопасности, изучаемый препарат относится к 4-му классу опасности – вещества малоопасные. Влияние на слизистые оболочки и возможное раздражающее действие изучали при нанесении препарата в дозе 5 мг на роговицу левого глаза кроликов, правый глаз был контролем. Раздражений при нанесении на кожу крыс, а также на конъюнктиву глаз кроликов препарат не вызывает. Хроническую токсичность препарата изучали на молодняке крупного рогатого скота черно-пестрой породы. Подопытным животным препарат задавали орально в дозах 1500 и 750 мг/кг в течение 30 дней. За животными вели наблюдение весь период эксперимента. В результате исследования установлено, что в хроническом эксперименте препарат отрицательного действия на организм молодняка крупного рогатого скота не оказывает

Food Supply and Seawater pCO2 Impact Calcification and Internal Shell Dissolution in the Blue Mussel Mytilus edulis

Progressive ocean acidification due to anthropogenic CO2 emissions will alter marine ecosytem processes. Calcifying organisms might be particularly vulnerable to these alterations in the speciation of the marine carbonate system. While previous research efforts have mainly focused on external dissolution of shells in seawater under saturated with respect to calcium carbonate, the internal shell interface might be more vulnerable to acidification. In the case of the blue mussel Mytilus edulis, high body fluid pCO2 causes low pH and low carbonate concentrations in the extrapallial fluid, which is in direct contact with the inner shell surface. In order to test whether elevated seawater pCO2 impacts calcification and inner shell surface integrity we exposed Baltic M. edulis to four different seawater pCO2 (39, 142, 240, 405 Pa) and two food algae (310–350 cells mL−1 vs. 1600–2000 cells mL−1) concentrations for a period of seven weeks during winter (5°C). We found that low food algae concentrations and high pCO2 values each significantly decreased shell length growth. Internal shell surface corrosion of nacreous ( = aragonite) layers was documented via stereomicroscopy and SEM at the two highest pCO2 treatments in the high food group, while it was found in all treatments in the low food group. Both factors, food and pCO2, significantly influenced the magnitude of inner shell surface dissolution. Our findings illustrate for the first time that integrity of inner shell surfaces is tightly coupled to the animals' energy budget under conditions of CO2 stress. It is likely that under food limited conditions, energy is allocated to more vital processes (e.g. somatic mass maintenance) instead of shell conservation. It is evident from our results that mussels exert significant biological control over the structural integrity of their inner shell surfaces

Advances in modelling of biomimetic fluid flow at different scales

The biomimetic flow at different scales has been discussed at length. The need of looking into the biological surfaces and morphologies and both geometrical and physical similarities to imitate the technological products and processes has been emphasized. The complex fluid flow and heat transfer problems, the fluid-interface and the physics involved at multiscale and macro-, meso-, micro- and nano-scales have been discussed. The flow and heat transfer simulation is done by various CFD solvers including Navier-Stokes and energy equations, lattice Boltzmann method and molecular dynamics method. Combined continuum-molecular dynamics method is also reviewed

It’s Not a Bug, It’s a Feature: Functional Materials in Insects

Over the course of their wildly successful proliferation across the earth, the insects as a taxon have evolved enviable adaptations to their diverse habitats, which include adhesives, locomotor systems, hydrophobic surfaces, and sensors and actuators that transduce mechanical, acoustic, optical, thermal, and chemical signals. Insect‐inspired designs currently appear in a range of contexts, including antireflective coatings, optical displays, and computing algorithms. However, as over one million distinct and highly specialized species of insects have colonized nearly all habitable regions on the planet, they still provide a largely untapped pool of unique problem‐solving strategies. With the intent of providing materials scientists and engineers with a muse for the next generation of bioinspired materials, here, a selection of some of the most spectacular adaptations that insects have evolved is assembled and organized by function. The insects presented display dazzling optical properties as a result of natural photonic crystals, precise hierarchical patterns that span length scales from nanometers to millimeters, and formidable defense mechanisms that deploy an arsenal of chemical weaponry. Successful mimicry of these adaptations may facilitate technological solutions to as wide a range of problems as they solve in the insects that originated them.Insects have evolved manifold optimized solutions to everyday problems. The diversity and precision of their hierarchical material adaptations often outsmart and outperform current man‐made approaches. These materials hence provide an excellent basis for the inspiration of new technological approaches by taking design cues from nature’s solutions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143760/1/adma201705322.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143760/2/adma201705322_am.pd