Hierarchical Self‐Assembly of Poly‐Pseudorotaxanes into Artificial Microtubules

Hierarchical self‐assembly of building blocks over multiple length scales is ubiquitous in living organisms. Microtubules are one of the principal cellular components formed by hierarchical self‐assembly of nanometer‐sized tubulin heterodimers into protofilaments, which then associate to form micron‐length‐scale, multi‐stranded tubes. This peculiar biological process is now mimicked with a fully synthetic molecule, which forms a 1:1 host‐guest complex with cucurbit[7]uril as a globular building block, and then polymerizes into linear poly‐pseudorotaxanes that associate laterally with each other in a self‐shape‐complementary manner to form a tubular structure with a length over tens of micrometers. Molecular dynamic simulations suggest that the tubular assembly consists of eight poly‐pseudorotaxanes that wind together to form a 4.5 nm wide multi‐stranded tubule.     

A Highly Efficient All‐Solid‐State Lithium/Electrolyte Interface Induced by an Energetic Reaction

The energetic chemical reaction between Zn(NO₃)₂ and Li is used to create a solid‐state interface between Li metal and Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) electrolyte. This interlayer, composed of Zn, ZnLi_x alloy, Li₃N, Li₂O, and other species, possesses strong affinities with both Li metal and LLZTO and affords highly efficient conductive pathways for Li⁺ transport through the interface. The unique structure and properties of the interlayer lead to Li metal anodes with longer cycle life, higher efficiency, and better safety compared to the current best Li metal electrodes operating in liquid electrolytes while retaining comparable capacity, rate, and overpotential. All‐solid‐state Li||Li cells can operate at very demanding current–capacity conditions of 4 mA cm^?2–8 mAh cm^?2. Thousands of hours of continuous cycling are achieved at Coulombic efficiency >99.5 % without dendrite formation or side reactions with the electrolyte.     

Water Extract of Fritillariae thunbergii Bulbus Inhibits RANKL-Mediated Osteoclastogenesis and Ovariectomy-Induced Trabecular Bone Loss

Fritillariae thunbergii bulbus has been widely used to treat symptoms of coughs and airway congestion in the chest due to pathological colds and damp phlegm in traditional Chinese medicine. Despite its long history of traditional use, its pharmacological activities on osteoclastogenesis and osteoporosis have not been evaluated. This study investigated the effects of the water extract of Fritillariae thunbergii bulbus (WEFT) on osteoclast differentiation in bone marrow-derived macrophage cells and on ovariectomy (OVX)-induced osteoporosis in mice. We found that WEFT significantly inhibited osteoclastogenesis by downregulating the receptor activator of the NF-κB ligand (RANKL) signaling-induced nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) expression. In an OVX-induced osteoporosis model, WEFT significantly prevented the OVX-induced trabecular loss of femurs, accompanied by a reduction in fat accumulation in the bone marrow and liver. In addition, WEFT significantly prevented weight gain and gonadal fat gain without recovering uterine atrophy. Using ultrahigh-performance liquid chromatography-tandem mass spectrometry, seven alkaloids (peimisine glucoside, yibeissine, peiminoside, sipeimine-glucoside, peimisine, peimine, and peiminine) were identified in WEFT. The results of this study suggest that WEFT can be a potential pharmacological candidate to reduce menopausal osteoporosis and menopause-related symptoms, such as fat accumulation.     

Domain-Specific On-Device Object Detection Method

Object detection is a significant activity in computer vision, and various approaches have been proposed to detect varied objects using deep neural networks (DNNs). However, because DNNs are computation-intensive, it is difficult to apply them to resource-constrained devices. Here, we propose an on-device object detection method using domain-specific models. In the proposed method, we define object of interest (OOI) groups that contain objects with a high frequency of appearance in specific domains. Compared with the existing DNN model, the layers of the domain-specific models are shallower and narrower, reducing the number of trainable parameters; thus, speeding up the object detection. To ensure a lightweight network design, we combine various network structures to obtain the best-performing lightweight detection model. The experimental results reveal that the size of the proposed lightweight model is 21.7 MB, which is 91.35% and 36.98% smaller than those of YOLOv3-SPP and Tiny-YOLO, respectively. The f-measure achieved on the MS COCO 2017 dataset were 18.3%, 11.9% and 20.3% higher than those of YOLOv3-SPP, Tiny-YOLO and YOLO-Nano, respectively. The results demonstrated that the lightweight model achieved higher efficiency and better performance on non-GPU devices, such as mobile devices and embedded boards, than conventional models.     

Photon correlation spectroscopy of bulk poly(n-hexyl methacrylate) near the glass transition

Slowly relaxing longitudinal density fluctuations in an optically perfect sample of bulk poly(n-hexyl methacrylate) (PHMA) have been studied by photon correlation spectroscopy in the temperature range 10–36°C. The glass transition temperature for this sample was measured to be T_g = −3°C by differential scanning calorimetry. The optical purity of the sample was verified by Rayleigh-Brillouin spectroscopy and the Landau-Placzek ratio was observed to be 2.3 at 25°C. Light-scattering relaxation functions were obtained over the time range 10⁻⁶-1 s. The shape of the relaxation functions broadened as the temperature was lowered towards the glass transition. Quantitative analysis of the results was carried out using the Kohlrausch-Williams-Watts (KWW) function to obtain average relaxation times, 〈τ〉, and width parameters, β. The width parameter decreased from 0.43 to 0.21 over the temperature interval, as suggested by visual inspection. Average relaxation times shifted with temperature in a manner consistent with previous mechanical studies of the primary glass-rubber relaxation in PHMA. The relaxation functions were also analyzed in terms of a distribution of relaxation rates, G(Γ). The calculated distributions were unimodal at all temperatures. The average relaxation times obtained from G(Γ) were in agreement with the KWW analysis, and the shape of the distribution broadened as the sample was cooled. The rate at which G(Γ) displayed a maximum correlated well with the corresponding frequency of maximum dielectric loss for PHMA. The temperature dependence of these two quantities could be reproduced with an Arrhenius activation energy of 21 Kcal/mol. A consistent picture of the molecular dynamics of PHMA near the glass transition requires a strong secondary relaxation process with a different temperature dependence from the primary glass-rubber relaxation. The present results suggest that the behavior of PHMA is similar to the other poly(alkyl methacrylates). © 1996 John Wiley & Sons, Inc.     

Alcohol Selective Optical Sensor Based on Porous Cholesteric Liquid Crystal Polymer Networks

A responsive hydrogen-bonded cholesteric liquid crystal polymer (CLCP) film with controlled porosity was fabricated as an optical sensor to distinguish between methanol and ethanol in alcohol solutions. To facilitate responding the alcohols, porosity was generated by removing the nonreactive liquid crystal agent, and the hydrogen bridges of CLCP were broken. The sensitivities of CLCPs to ethanol and methanol were obtained by monitoring the wavelength shifts of the transmission spectrum at different alcohol concentrations and ratios of methanol/ethanol. Changes in the central wavelength of the CLCP network transmission spectrum allowed the methanol–ethanol ratio to be discriminated. A linear relationship between wavelength shift of CLCP networks and alcohol concentration was obtained experimentally, and the sensor characteristics were explored. The sensitivities of the CLCPs were 1.35 and 0.18 nm/% to ethanol and methanol, respectively. The sensing sensitivity of cholesteric networks to alcohol molecules increased as the methanol–ethanol ratio declined. Therefore, CLCP could act as a stimuli-responsive material to distinguish the concentrations of acetone and ethanol in mixed solutions. Furthermore, the impact of UV intensity for curing a CLC mixture on the sensing sensitivity to the different alcohol concentrations was also studied. The higher UV intensity could enhance the sensitivity to alcohol molecules and distinguishing ability between methanol and ethanol.     

On the Interfacial Flow Over Porous Media Composed of Packed Spheres: Part 1-Identification of the Effective Slip Length

Transport in Porous Media - The effective slip length at the interface between pure fluid flow and porous media composed of packed spheres has been accurately characterized. In this study, as the...     

Dynamics of Atomic and Molecular Hydrogen Elimination from Hydrocarbons at VUV Excitation

Elimination of atomic hydrogen (H) and molecular hydrogen (H₂) are important elementary chemical processes in photochemistry and combustion chemistry. Recently, unique and sensitive detection techniques for atomic and molecular hydrogen detection were developed in our laboratory. Using the advanced molecular beam methods, we have studied the photodissociation of a few typical hydrocarbons at 157 nm excitation, especially their atomic and molecular hydrogen elimination processes. In this report, we will briefly describe the results from photodissociation of propane, ethylene, propyne and methanol at 157 nm excitation. These molecules represent different classes of hydrocarbons such as alkane, alkene, alkyne and alcohol. Through careful studies on differently deuterated compounds, clear pictures of selective atomic and molecular hydrogen elimination processes can be constructed for all of the above compounds. These results will help us to understand the dissociation dynamics of the small hydrocarbon molecules.     

Preparation of anion-exchange membrane based on block copolymers: Part 1. Amination of the chloromethylated copolymers

The anion-exchange membrane was prepared by a two-step synthesis: chloromethylation of the homemade block copolymers of polysulfone (PSf) and polyphenylenesulfidesulfone (PPSS) in the first step with subsequent amination by means of trimethylamine in the second step. The lowest measured area resistivities, equilibrated in 2 mol/dm³ KCl aqueous solution, were 4.5–3.30 Ω cm². The anion-exchange capacity reached up to 0.92 meq/(g-dry-resin), and the transport number of chlorine anion was in the 0.6–0.7 range.     

Electrochemical Conversion of CO2 to Syngas with Controllable CO/H2 Ratios over Co and Ni Single‐Atom Catalysts

The electrochemical CO₂ reduction reaction (CO₂RR) to yield synthesis gas (syngas, CO and H₂) has been considered as a promising method to realize the net reduction in CO₂ emission. However, it is challenging to balance the CO₂RR activity and the CO/H₂ ratio. To address this issue, nitrogen‐doped carbon supported single‐atom catalysts are designed as electrocatalysts to produce syngas from CO₂RR. While Co and Ni single‐atom catalysts are selective in producing H₂ and CO, respectively, electrocatalysts containing both Co and Ni show a high syngas evolution (total current >74 mA cm^?2) with CO/H₂ ratios (0.23–2.26) that are suitable for typical downstream thermochemical reactions. Density functional theory calculations provide insights into the key intermediates on Co and Ni single‐atom configurations for the H₂ and CO evolution. The results present a useful case on how non‐precious transition metal species can maintain high CO₂RR activity with tunable CO/H₂ ratios.