Structure-defined metal–organic frameworks (MOFs) are of interest because rational design and construction allow us to develop good proton conductors or possibly control the proton conductivity in ...solids. We prepared a highly proton-conductive MOF (NH4)2(adp)Zn2(ox)3·nH2O (abbreviated to 1· n H 2 O, adp: adipic acid, ox: oxalate, n = 0, 2, 3) having definite crystal structures and showing reversible structural transformations among the anhydrate (1), dihydrate (1·2H 2 O), and trihydrate (1·3H 2 O) phases. The crystal structures of all of these phases were determined by X-ray crystallography. Hydrogen-bonding networks consisting of ammonium ions, water molecules, and carboxylic acid groups of the adipic acids were formed inside the two-dimensional interlayer space in hydrated 1·2H 2 O and 1·3H 2 O. The crystal system of 1 or 1·2H 2 O (P21/c, No. 14) was changed into that of 1·3H 2 O (P1̅, No. 2), depending on water content because of rearrangement of guests and acidic molecules. Water molecules play a key role in proton conduction as conducting media and serve as triggers to change the proton conductivity through reforming hydrogen-bonding networks by water adsorption/desorption processes. Proton conductivity was consecutively controlled in the range from ∼10–12 S cm–1 (1) to ∼10–2 S cm–1 (1·3H 2 O) by the humidity. The relationships among the structures of conducting pathways, adsorption behavior, and proton conductivity were investigated. To the best of our knowledge, this is the first example of the control of a crystalline proton-conducting pathway by guest adsorption/desorption to control proton conductivity using MOFs.
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Behavior is studied in several disciplines including psychology, ethology, and neuroscience. However, the definition of behavior has never been consistent not only across disciplines, but also ...between researchers within a field. The present article reviews this inconsistency and confusion both in the modern research fields and historical literatures. We find that the definitions of behavior are closely tied to the system of the fields, and the inconsistency of definitions rises from the differences of fields. As a result, the complete definition of behavior seems challenging. Instead of seeking for the complete definition, it is more productive to identify what makes definitions of behavior inconsistent. The article, thus, proposes three points to reduce the confusion accompanied by the inconsistency of the definitions: (1) stipulation of an organism as a whole and environment (2) internal-external distinction, and (3) formulation of the relationships between an organism and environment.
In this critical review we highlight recent advances in the use of peptide- and protein-related materials as smart building blocks in nanotechnology. Peptides and proteins can be very practical for ...new material synthesis and device fabrications. For example, peptides and proteins have superior specificity for target binding as seen in the antibody recognition and this biological recognition function can be used to assemble them into specific structures and shapes in large scale, as observed in the S-layer protein assembly. Collagens are assembled from triple helix peptides in micron-size with precise recognition between peptides and these biological assemblies can undergo smart structural change with pH, ionic strength, temperature, electric/magnetic fields. In addition, assemblies of peptides can template complex 3D crystallization processes with catalytic function, thus enabling to grow various materials in physiological conditions at low temperature in aqueous solution. The biomimetic growth of nanomaterials in aqueous solution is extremely useful when they are applied to therapeutics and medical imaging in vivo since these nanomaterials will be well dispersed in bodies. Peptides also play significant roles in signal transduction pathways in cells. For example, neuropeptides are used as neurotransmitters between synapses and these peptides bind receptors on the surface of cells to cascade the signal transduction. These versatile functions of peptides are extremely practical and here we discuss them with examples of relevant applications such as nanoreactors, sensors, electronics, and stimulus-responsive materials. It should be noted that peptide/protein assemblies can be applied to build up micron-scale materials that still feature excellent nano-scale ensembles, which essentially bridges the nano-world and the micro-world (86 references).
A variety of microsystems have been developed that harness energy and convert it to mechanical motion. Here we have developed new autonomous biochemical motors by integrating a metal-organic ...framework (MOF) and self-assembling peptides. The MOF is applied as an energy-storing cell that assembles peptides inside nanoscale pores of the coordination framework. The nature of peptides enables their assemblies to be reconfigured at the water/MOF interface, and thus converted to fuel energy. Reorganization of hydrophobic peptides can create a large surface-tension gradient around the MOF that can efficiently power its translational motion. As a comparison, the velocity normalized by volume for the diphenylalanine-MOF particle is faster and the kinetic energy per unit mass of fuel is more than twice as great as that for previous gel motor systems. This demonstration opens the route towards new applications of MOFs and reconfigurable molecular self-assembly, possibly evolving into a smart autonomous motor capable of mimicking swimming bacteria and, with integrated recognition units, harvesting target chemicals.
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A method for the simultaneous determination of five triarylmethane colorants (brilliant blue FCF, patent blue V, patent blue VF, fast green FCF, and green S) in syrup samples was proposed by applying ...multivariate curve resolution to second-derivative visible absorption spectra in citrate and carbonate buffer solutions. Even for heavily overlapping spectra, adopting second-derivative spectra and multiway analysis in citrate and carbonate buffer solutions enhanced specificity for the analytes and achieved prediction performance with a coefficient of determination (
R
2
) > 0.90, root mean square error of prediction (RMSEP) < 0.20 mg/L, and limit of detection (LOD) < 0.50 mg/L for all five analytes. The basis set expansion method succeeded in a reasonable estimation of the second-derivative spectra with the interferant. For commercial syrup samples, the present method predicted results without significant differences compared to the results measured using liquid chromatography-mass spectrometry. The proposed method provides a rapid alternative to liquid chromatography techniques for the quantification of multiple colorants in food samples.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The physical properties of genuine and deliberate facial expressions remain elusive. This study focuses on observable dynamic differences between genuine and deliberate expressions of surprise based ...on the temporal structure of facial parts during emotional expression. Facial expressions of surprise were elicited using multiple methods and video recorded: senders were filmed as they experienced genuine surprise in response to a jack-in-the-box (Genuine), other senders were asked to produce deliberate surprise with no preparation (Improvised), by mimicking the expression of another (External), or by reproducing the surprised face after having first experienced genuine surprise (Rehearsed). A total of 127 videos were analyzed, and moment-to-moment movements of eyelids and eyebrows were annotated with deep learning-based tracking software. Results showed that all surprise displays were mainly composed of raising eyebrows and eyelids movements. Genuine displays included horizontal movement in the left part of the face, but also showed the weakest movement coupling of all conditions. External displays had faster eyebrow and eyelid movement, while Improvised displays showed the strongest coupling of movements. The findings demonstrate the importance of dynamic information in the encoding of genuine and deliberate expressions of surprise and the importance of the production method employed in research.
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Pecking in birds is analogous to reaching and grasping movements in primates. Earlier studies on visuomotor control in birds, which were conducted mostly in pigeons, suggested that avian pecking is ...controlled feedforwardly, and is out of the control of visual guidance during movement. However, recent studies using crows suggested a role of vision in pecking control during movement. To unveil what visuomotor mechanisms underlie the flexibility of pecking in crows, the current study examined whether pigeons and crows adjust their pecking to the visual distortion induced by prisms. Because prisms induce visual shifts of object positions, birds were required to adjust their movements. Pecking kinematics were examined before and after attaching prisms in front of the birds’ eyes. Analysis of lateral deviation caused by the prisms showed that crows rapidly adjusted their pecking trajectories, but pigeons did slowly. Angular displacement also increased in pigeons after attachment of the prism but decreased in crows. These responses to prisms were consistent among individuals in pigeons but varied in crows, though the adjustment of pecking commonly succeeded in crows. These results suggest that pecking in pigeons predominantly involves feedforward control and that the movement is determined depending on the visual information available before the initiation of pecking. In contrast, the results from crows suggest that their pecking trajectories are corrected during the movement, supporting on-line visual control. Our findings were the first evidence to suggest the on-line visual control of pecking in birds.
Smiles are universal but nuanced facial expressions that are most frequently used in face-to-face communications, typically indicating amusement but sometimes conveying negative emotions such as ...embarrassment and pain. Although previous studies have suggested that spatial and temporal properties could differ among these various types of smiles, no study has thoroughly analyzed these properties. This study aimed to clarify the spatiotemporal properties of smiles conveying amusement, embarrassment, and pain using a spontaneous facial behavior database. The results regarding spatial patterns revealed that pained smiles showed less eye constriction and more overall facial tension than amused smiles; no spatial differences were identified between embarrassed and amused smiles. Regarding temporal properties, embarrassed and pained smiles remained in a state of higher facial tension than amused smiles. Moreover, embarrassed smiles showed a more gradual change from tension states to the smile state than amused smiles, and pained smiles had lower probabilities of staying in or transitioning to the smile state compared to amused smiles. By comparing the spatiotemporal properties of these three smile types, this study revealed that the probability of transitioning between discrete states could help distinguish amused, embarrassed, and pained smiles.
Gas sorption and molecular (ionic) storages are important functionalities in porous materials. In molecular porous crystal {{RuIII(H2bim)3(TMA)}2·mH2O} n , the hydrophilic nanochannel accommodates ...the water nanotube (WNT) composed of a 4461074-polyhedral cage. The experiment on weight change reveals that the cage structure is maintained above 50% RH (relative humidity) at 294 K. As the relative humidity is reduced from 80 to 50% RH, the proton conductivity exponentially decreases from 0.02 to 0.01 (Ω cm)−1 owing to the dehydration of inner H2O molecules through WNT, which acts as a nanofluidic channel. Upon pressurizing Xe at 0.4 MPa for 50% RH, the proton conductivity exponentially decreases and approaches 0 (Ω cm)−1. The infrared and 129Xe-NMR experiments make clear that Xe together with about 25H2O molecules per cage are stabilized in WNT at low pressures compared to Xe-clathrate hydrate. Those results experimentally demonstrate that the Xe hydrate inhibits the proton conduction. The formation of Xe hydrate is characterized by fast and slow processes with a translational diffusion constant of 1 × 10–10 and 6 × 10–12 m2/s, respectively. The reorganization and hardening of the hydrogen-bonding water network are considered to diminish the conducting pass of proton, and to reduce the protonic transfer from H3O+ to adjacent H2O.
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