84 research outputs found

    Neuronal messenger ribonucleoprotein transport follows an aging Lévy walk

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    Localization of messenger ribonucleoproteins (mRNPs) plays an essential role in the regulation of gene expression for long-term memory formation and neuronal development. Knowledge concerning the nature of neuronal mRNP transport is thus crucial for understanding how mRNPs are delivered to their target synapses. Here, we report experimental and theoretical evidence that the active transport dynamics of neuronal mRNPs, which is distinct from the previously reported motor-driven transport, follows an aging Levy walk. Such nonergodic, transient superdiffusion occurs because of two competing dynamic phases: the motor-involved ballistic run and static localization of mRNPs. Our proposed Levy walk model reproduces the experimentally extracted key dynamic characteristics of mRNPs with quantitative accuracy. Moreover, the aging status of mRNP particles in an experiment is inferred from the model. This study provides a predictive theoretical model for neuronal mRNP transport and offers insight into the active target search mechanism of mRNP particles in vivo.1111sciescopu

    Bioinspired reversible hydrogel adhesives for wet and underwater surfaces

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    Stable and reversible adhesion to wet surfaces is challenging owing to water molecules at the contact interface. In this study, we develop a hydrogel-based wet adhesive, which can exhibit strong and reversible adhesion to wet and underwater surfaces as well as to dry surfaces. The remarkable wet adhesion of the hydrogel adhesive is realized based on a synergetic integration of bioinspired microarchitectures and water-friendly and water-absorbing properties of the polymeric hydrogel. Under dry conditions, the microstructured hydrogel adhesive exhibits strong van der Waals interaction-based adhesion, while under underwater conditions, it can maximize capillary adhesion. Consequently, the hydrogel adhesive exhibits remarkable adhesion strengths for dry, moist, and submerged substrates. Maximum normal and shear adhesion strengths of 423 and 384, 492 and 340, and 253 and 21 kPa are achieved with the hydrogel adhesive for dry, moist, and submerged substrates, respectively. Our results demonstrate that strong wet and underwater adhesion can be achieved only with the hydrogel-based adhesive with simple microscale architecture

    Flexible and Shape-Reconfigurable Hydrogel Interlocking Adhesives for High Adhesion in Wet Environments Based on Anisotropic Swelling of Hydrogel Microstructures

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    This study presents wet-responsive, shape-reconfigurable, and flexible hydrogel adhesives that exhibit strong adhesion under wet environments based on reversible interlocking between reconfigurable microhook arrays. The experimental investigation on the swelling behavior and structural characterization of the hydrogel microstructures reveal that the microhook arrays undergo anisotropic swelling and shape transformation upon contact with water. The adhesion between the interlocked microhook arrays is greatly enhanced under wet conditions because of the hydration-triggered shape reconfiguration of the hydrogel microstructures. Furthermore, wet adhesion monotonically increases with water-exposure time. A maximum adhesion force of 79.9 N cm-2 in the shear direction is obtained with the hydrogel microhook array after 20 h of swelling, which is 732.3% greater than that under dry conditions (i.e., 9.6 N cm-2). A simple theoretical model is developed to describe the measured adhesion forces. The results are in good agreement with the experimental data

    Evaluation Indicators for Priorities of Standardization in Traditional Medicine: using Analytic Hierarchy Process(AHP)

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    The entire manuscript is available for download as a single PDF file. Higher-resolution images are unavailable. For assistance, please contact [email protected]. Fieldwork Team: Philippe Beaujard (Director of Research, French National Centre for Scientific Research). Technical Team: Dr. Vika Zafrin (Digital Scholarship Librarian, BU Libraries), Eleni Castro (OpenBU and Electronic Theses & Dissertations Librarian, BU Libraries), Dr. Fallou Ngom (Director of the African Studies Center), Dr. Peter Quella (Assistant Director, African Studies Center), Mustapha Hashim Kurfi (PhD Candidate, Department of Political Science), and Zachary Gersten (Research Assistant, African Studies Center). This collection of Malagasy Ajami materials is copied as part of the African Studies Center’s African Ajami Library. This project is partly funded by the BU African Studies Center. We thank Dr. Tim Longman, past Director of the African Studies Center, and the entire African Studies team for their support. For Inquiries: Please contact Professor Fallou Ngom ([email protected]).The material is the fourth part of the second of two texts copied and owned by Jean, a diviner-healer (called ombiasy in Malagasy). Jean belonged to the Anakara Clan and lived in a village called Vatomasina in the Antemoro region (in the valley of the Matatàña River). The original author of the material is unknown. The material was photographed between 1983 and 1990. The material was written on paper school notebooks. While the exact content of material is unknown, it is believed to contain guidance for charms, divination, and healing through prayers, geomancy, and astrology

    Intracellular gallium nitride microrod laser

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    We report laser emission from gallium nitride (GaN) microrods that are introduced into mammalian cells and the application of these microrods for cell labeling. GaN microrods were grown on graphene-coated SiO2/Si substrates by metal-organic vapor phase epitaxy. The GaN microrods are easily detached from the substrates because of the weakness of the van der Waals forces between GaN and graphene. The uptake of microrods into HeLa cells via endocytosis and viability after uptake were investigated. Normal cellular activities, including migration and division, were observed over 2 weeks in culture. Furthermore, the photoluminescence spectra of the internalized microrods exhibited sharp laser emission peaks with a low lasing threshold of 270kW/cm(2)

    Multifunctional Smart Ball Sensor for Wireless Structural Health Monitoring in a Fire Situation

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    A variety of sensor systems have been developed to monitor the structural health status of buildings and infrastructures. However, most sensor systems for structural health monitoring (SHM) are difficult to use in extreme conditions, such as a fire situation, because of their vulnerability to high temperature and physical shocks, as well as time-consuming installation process. Here, we present a smart ball sensor (SBS) that can be immediately installed on surfaces of structures, stably measure vital SHM data in real time and wirelessly transmit the data in a high-temperature fire situation. The smart ball sensor mainly consists of sensor and data transmission module, heat insulator and adhesive module. With the integrated device configuration, the SBS can be strongly attached to the target surface with maximum adhesion force of 233.7-N and stably detect acceleration and temperature of the structure without damaging the key modules of the systems even at high temperatures of up to 500 degrees C while ensuring wireless transmission of the data. Field tests for a model pre-engineered building (PEB) structure demonstrate the validity of the smart ball sensor as an instantly deployable, high-temperature SHM system. This SBS can be used for SHM of a wider variety of structures and buildings beyond PEB structures

    Ghrelin Regulates Hippocampal Neurogenesis in Adult Mice

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