Photomechanical crystals-a subclass of crystalline materials that exhibit macroscopic deformation under light illumination-have applications in light-driven actuators and soft robots. However, they are associated with several drawbacks, such as size limitations to the millimeter scale and poor processability, which hinder their practical applications. Although several composite materials in which photomechanical crystals are aligned in a polymer membrane have been developed, the size of the photomechanical crystals has not been optimized, nor have the mechanical properties of the composite materials been investigated in detail. Here we demonstrated centimeter-scale, light-responsive, crystal-polymer composite films consisting of salicylideneaniline microcrystals and ultraviolet (UV)-curing resins. Desired-size single microcrystals were prepared by using the reprecipitation method or sublimation. Upon UV irradiation to the films, they bent away from the light source through photoisomerization or the photothermal effect, demonstrating their ability as an energy converter from light to kinetic work. The composite films exhibited distinct bending reversibility depending on the polymer matrix, originating from the polymer's different mechanical properties. Our composites provide insight into the development of centimeter-scale photomechanical materials with high processability, and, ultimately, light-fueled actuators and soft robots.

Chirality appears in many molecules, crystals, and nanostructures and plays an important role in their physicochemical and biological functions. Because biological systems exhibit a chiral bias, they respond differently to each chiral enantiomer. Therefore, it is very important to develop methods or devices that can discriminate the enantiomers easily. Metallic nanostructures such as nanoparticles, nanorods, and mesoporous films exhibit significantly enhanced optical responses due to localized surface plasmon resonance. The optical properties of these nanostructures are highly dependent on their size, shape, and elemental composition, all of which can be precisely controlled through optimized chemical synthesis. In this study, we developed a hierarchical nanostructure of chiral Au nanostructures on Au coral structures, which were synthesized on transparent conductive oxide substrates using only electrochemical techniques. By considering both the substitution of chloride ions in [AuCl4]- with cysteine in the electrolyte solution and the subsequent reduction of the Au(III) complexes, we successfully controlled the morphology of the Au nanostructures, which exhibit circular dichroism. Furthermore, we explored the potential for chiral discrimination using these substrates. The hierarchical chiral Au nanostructures on Au coral structures enhanced the SERS intensity relative to Au corals alone and produced enantiomer-dependent SERS responses for L- and D-phenylalanine, demonstrating their potential for chiral discrimination.

Abstract Thalidomide (TD) is a representative chiral pharmaceutical for which accurate evaluation of its chirality is essential to ensure drug safety, as there are significant differences in biological activity between its enantiomers. In this study, chiroptical properties of TD were systematically investigated through circular dichroism and optical activity measurements in polar aprotic acetonitrile. NMR/MS analyses and quantum chemical calculations revealed that the observed responses mainly originate from monomeric TD and arise from mixed n → π* and π → π* electronic transitions.

Optical anisotropy is a fundamental spectroscopic property of condensed matters and is crucial for understanding their electronic structures, molecular orientations, and symmetry. Among its aspects, linear birefringence (LB) and linear dichroism (LD) are important because they reflect differences in refractive indices and absorption coefficients for orthogonally polarized light components. The high-accuracy universal polarimeter (HAUP) method is widely used for measuring LB and LD because of its high sensitivity. The conventional HAUP measurement principle is based on the extinction position, where the transmitted light intensity is minimized. However, such measurement becomes challenging for strongly absorbing samples or in short-wavelength regions with weak light intensity. To overcome these limitations, we have developed a HAUP measurement principle based on the diagonal position, where the transmitted light intensity is maximized. The measurement equations are expanded around the diagonal position, giving a different equation structure from the extinction-position method. This configuration simplifies the measurement procedure, eliminates two-dimensional measurements and eliminates systematic errors such as parasitic ellipticities of the polarizer and analyzer. We have applied this measurement principle to MgF2, and a strongly absorbing high-temperature cuprate superconductor, a Bi2Sr2CaCu2O8+δ crystals. The measured LB and LD values agreed well with those obtained using the conventional extinction-position method.

The RING-H2 type E3 ligase Praja family is composed of E3 ubiquitin-protein ligases Praja1 and Praja2, which promote the degradation of substrates through the ubiquitin-proteasome system. Both paralogs contribute to neuronal maturation and differentiation, indicating a significant role in the nervous system. Aggregation-prone proteins associated with neurodegenerative diseases, including TAR DNA-binding protein 43 (TDP-43) and α-synuclein, are degraded and/or suppressed by Praja1. Furthermore, the expression level of the microtubule-associated protein tau (MAPT) gene, which is frequently mutated in Alzheimer's disease, is regulated by Praja2. Although the Praja family has been shown to recognize various aggregation-prone proteins as substrates, it has not been determined whether tau, a key protein that aggregates in tauopathies, is also recognized by Praja proteins. In this study, we show that Praja1, but not Praja2, recognizes tau as a candidate substrate. We observed that the tau protein level in human neuroblastoma SH-SY5Y cells decreased depending on the E3 ligase activity of Praja1. Furthermore, the in vivo/in vitro ubiquitination assay showed that Praja1 ubiquitinates tau, indicating that it is a target substrate. Next, by combining ancestral sequence reconstruction and mutational analysis, we revealed that the Praja1-tau interaction began just after the duplication of the Praja family in the common ancestor of placentals. Lastly, to test whether this interaction is disrupted under pathological conditions, P301L tau was introduced, resulting in a degradation similar to that of wild-type tau. These results reveal an unidentified mechanism of tau proteostasis by Praja1 and may provide insight into the pathogenesis of neurodegenerative diseases, including tauopathy.

Mechanical stretch critically influences skeletal muscle physiology, yet its role in myoblast differentiation and the associated molecular mechanisms have not been fully clarified. This study investigated the effects of uniaxial cyclic mechanical stretch (UnCyMSt) on differentiation of mouse myoblast C2C12 cells, focusing particularly on the potential involvement of eukaryotic initiation factor 2 alpha (eIF2α), a key regulator maintaining muscle stem cell quiescence. To apply mechanical stretch, C2C12 cells were cultured on polydimethylsiloxane surfaces covalently immobilized with collagen (Col-GA-PDMS), ensuring stable cell adhesion under UnCyMSt, whereas cells cultured on physically adsorbed collagen surfaces (Col-PDMS) detached under similar conditions. Under differentiation conditions, UnCyMSt markedly inhibited myoblast differentiation, as evidenced by suppressed expression of the differentiation marker myogenin. Additionally, stretched cells aligned perpendicular to the direction of mechanical stretch application. Given the established role of phosphorylated eIF2α (p-eIF2α) in maintaining myoblast quiescence, we investigated whether UnCyMSt inhibits differentiation by modulating eIF2α phosphorylation at serine 51. UnCyMSt did not prevent the progressive dephosphorylation of eIF2α during differentiation induction. Correspondingly, expression levels of activating transcription factor 4 (ATF4), downstream of p-eIF2α, also decreased under UnCyMSt. Our results demonstrate that UnCyMSt inhibits C2C12 myoblast differentiation without sustained phosphorylated eIF2α, suggesting the involvement of alternative mechanosensitive signaling pathways. These findings provide new insights into mechanical regulation of muscle differentiation and highlight the need for further exploration into stretch-responsive molecular mechanisms influencing myogenesis.

Cannabinoid receptor type 1 (CB1R) plays a key role in neuronal homeostasis, synaptic plasticity, and neuroprotection. CB1R antagonists typically protect against CB1R agonists-induced neurotoxicity. However, we previously found that the CB1R antagonists rimonabant and its analog AM251 can also be neurotoxic: under serum-free conditions, these compounds induce apoptosis in human neuroblastoma SH-SY5Y cells through mitochondrial damage and endoplasmic reticulum (ER) stress. To elucidate the mechanisms of this neurotoxicity, we examined the effects of CB1R agonists. We co-treated SH-SY5Y cells with rimonabant or AM251 in combination with either the CB1R agonist arachidonyl 2-chloroethylamide (ACEA) or WIN 55212-2 mesylate (WIN). ACEA, but not WIN, protected cells from rimonabant- and AM251-induced apoptosis. While ACEA had only a limited effect on mitochondrial damage, it significantly reduced phosphorylation of the eukaryotic initiation factor 2 alpha (eIF2α), a key marker of ER stress. Given that ACEA also functions as an agonist of transient receptor potential vanilloid 1 (TRPV1), we investigated its role in ACEA-mediated neuroprotection. The TRPV1 antagonist capsazepine blocked ACEA's protective effects, suggesting that ACEA acts through TRPV1 rather than CB1R. ACEA also prevented apoptosis induced by camptothecin, a well-established apoptosis inducer, through a similar capsazepine-sensitive mechanism, demonstrating its broader protective effects against apoptosis. These findings indicate that rimonabant and AM251 induce neurotoxicity independently of CB1R under serum-free conditions and that ER stress is likely to be a key target of CB1R-independent neuroprotection by ACEA. Our study highlights the complexity of CB1R ligand-associated neurotoxicity and neuroprotection.

Praja1 is known as an E3 ubiquitin ligase that regulates multiple functions through protein degradation. It acquired nuclear localization signal after gene duplication and although studies have shown some significant roles of nuclear Praja1, comprehensive analysis still lacks. In this study, we performed comparative proteomics and biochemical analyses to elucidate the functions of Praja1 in the nucleus. First, proteomics analysis applied to nuclear localization deficient Praja1 exhibited signs of DNA damage response fluctuation. Subsequent comet assay revealed Praja1 protecting cells from various DNA damage sources. Similarly, cells lacking Praja1 became more sensitive to DNA damage-induced cell death, while E. coli expressing Praja1 exhibited resistance to DNA damage. To further elucidate the molecular basis of DNA protection, gel shift assay showed direct binding of Praja1 to DNA through electrostatic interactions within its intrinsically disordered region. Further in vitro damaging assay suggested that Praja1 may induce structural changes that enhance DNA repair efficiency upon binding to DNA. Together, these results provide insights into the evolutionarily novel role of nuclear Praja1 in protecting against DNA damage.

For the single crystals of thalidomide (C13H10N2O4, TD) grown by the solvent evaporation method, the temperature dependences of the crystal structures have been investigated over a wide temperature range between 100 and 423.15 K. Comparing the α-form of a racemic TD crystal, which consists of symmetric heterochiral dimers and belongs to P21/n space group, with the enantiomeric TD crystal, which belongs to P21 and consists of asymmetric (pseudosymmetric) homochiral dimers, there have been clear differences in the temperature-dependent changes of the lattice parameters, the isobaric linear thermal expansion coefficients (along the crystallographic and the principal Cartesian axes), the volumetric expansion coefficients of the unit cell, and the structures of hydrogen-bonded dimer in the crystal such as intra- and intermolecular dihedral angles, cavities (reaction cavities), and the hydrogen-bond length. In the asymmetric homochiral dimers, one monomer with a larger reaction cavity changes its intramolecular dihedral angle with temperature, while the other monomer with a smaller cavity does not. In contrast, in the symmetric heterochiral dimers, two monomers with the same cavity volume similarly change their intramolecular dihedral angles with the temperature. Such differences in the temperature-dependent conformational changes between asymmetric and symmetric dimers cause differences between enantiomeric and racemic crystals.

We reformulate the Leslie effects that describe the dynamic cross-couplings in chiral liquid crystals driven by the transport of heat, electric charge, and mass. The Ericksen--Leslie model is extended in the linear response framework by representing nematic order with the Q-tensor. Subsequently, the thermodynamic uncertainty relation is applied to identify the upper bounds of the Leslie cross-coupling coefficients. We reveal that the cross-coupling coefficients are dependent on the scalar order parameter and vanish in the isotropic phase. In addition, the chirality of the phase allows torque induced by a transport current parallel to the director. The mutual signs of the Leslie thermohydrodynamic and thermomechanical coefficients are likely to be opposite in calamitic liquid crystals, as suggested by recent experimental observations. Our model is applicable to the thermal, chemical, and electrical Leslie effects. The present arguments suggest that a common underlying principle may govern both the Leslie effects and the thermal Edelstein effect in chiral solid crystals attributed to chiral phonons.

Electrochemical adsorption offers a promising approach for the separation of monovalent cations, which is an important but challenging subject in separation science. However, progress in this area has been hampered by the lack of suitable materials with effective ion selectivity. In this work, we present the synthesis of covalent organic frameworks (COFs) functionalized with a series of crown ethers (NCx-TAB-COFs, x donate 12, 15, 18, indicating the size of crown ether) for the efficient and highly selective electrochemical capture of monovalent cations. In our design, crown ether moieties act as confinement sites, imparting high selectivity for different monovalent cations depending on the cavity dimensions of the crown ether present. COFs electrodes prepared using the novel crown-COFs exhibit superior performance for the selective sequestration of monovalent (alkali metal) cations. Notably, 18-crown-6 ether-substituted COF (NC18-TAB-COF) shows a remarkable selectivity (14.26) for K+ over Na+ and a substantial Rb+/Na+ selectivity of 22.4. Furthermore, NCx-TAB-COFs maintain their remarkable selectivity and capacity under mixed-cation conditions. Density functional theory calculations and molecular dynamics simulations suggest that the unexpectedly high selectivity for larger cations is likely due to diverse binding modes in conjunction with the porous structure of the COFs. Given their lower dehydration-free energies and smaller hydrodynamic radii, K+, Rb+, and Cs+ more readily permeate the confined channels of COFs. In contrast, Na+ and Li+, with higher dehydration-free energies and hydrodynamic radii, diffuse into the NCx-TAB-COFs structure at a much slower rate and are bound predominantly to the surfaces of the COFs.

Optical micro-printing provides a way to directly self-assemble photonic microchips with chiral liquid-crystalline photonic elements.

Titania films with a completely controlled hierarchical structure, at microscopic, mesoscopic, and macroscopic scales, are successfully prepared by carefully combining “top–down” and “bottom–up” nanoprocesses. The titania films are composed of regularly arranged anatase nanocrystals, which form a 2D hexagonal mesostructure with cylindrical mesopores. Furthermore, the cylindrical mesopores are aligned in one direction in the plane of the film over the whole area. Thus, hierarchical structural regularities over multiple length scales, i.e., atomic (10 −10 m), mesoscopic (10 −8 m), and macroscopic (10 −2 m) scales, are achieved. The mesoporous titania films with a controlled alignment are prepared via sol–gel chemistry using the self‐assembly process of amphiphilic molecules combined with a lithographically prepared anisotropic substrate with a fine wavy cross‐section. The carefully designed sol–gel process using Pluronic P123 as a structure‐directing agent allows the retention of the aligned mesoporous structure as well as the formation of crack‐free films even after the crystallization of titania. The anisotropic mesoporous structure with pore walls composed of high‐refractive‐index crystalline titania exhibits remarkable optical anisotropy, birefringence. This full‐multiscale structural control of an inorganic material, from atomic to centimeter scales, affords distinguished functionalities to artificially prepared nanomaterials, paving the way for creating new values.

To establish an efficient cultured meat production system, we developed a novel circular cell culture (CCC) system using microalgae (Alvikia littoralis NBRC 102761) cultured in an animal cell waste medium. To reduce the external nitrogenous fertilizer input in the A. littoralis culture, we grew microalgae in nitrogenous fertilizer-free media with an extract of the nitrogen-fixing cyanobacteria Anabaena sp. PCC 7120 and Scytonema sp. NIES-2130. The increase in A. littoralis cell concentration in seawater containing Scytonema extracts was 4.4-fold higher than that in nitrogenous fertilizer-free artificial seawater; however, it was 0.8-fold lower than that in fertilizer-enriched seawater. However, with the Anabaena extract, the increase in A. littoralis cell concentration was 14.6-fold higher than that in nitrogenous fertilizer-free artificial seawater and 2.1-fold higher in fertilizer-enriched seawater. Anabaena extract contained larger amounts of ammonium (7.6-fold) than Scytonema extract, which was considered to be linked to the efficient growth of A. littoralis. Alvikia littoralis consumed 97% of the ammonium in the Anabaena extract, demonstrating that microalgae proliferated using the nitrogen source of the extract. Amino acids were extracted 2.8 times more efficiently from A. littoralis cultured with Anabaena extract than from fertilizer-enriched seawater. Moreover, the concentration of A. littoralis cells increased 12.6-fold in the waste medium of animal cells and 19.0-fold in the waste medium with the Anabaena extract, indicating that the addition of the extract accelerated the growth of A. littoralis. The amount of ammonium increased in the waste culture medium with addition of Anabaena extract, and A. littoralis consumed 99% of the ammonium from the waste medium containing the extract. This microalgal culture method using Anabaena extract further improves the CCC system and could contribute to the establishment of a sustainable cultured meat production system that reduces the use of chemical fertilizers, crops and livestock, and also effectively uses waste.

Molecular crystals hold potential applications in soft and flexible devices because of their periodic arrangements, flexibility to design, lightweight, and tunable supramolecular connections. Their rich polymorphism offers the additional advantage that the properties of different crystal forms can be studied for a given molecular structure. This study focuses on the directional crystallization of salicylideneaniline to control its polymorphic alpha and beta forms. We discovered that upon directional crystallization from nonground beta crystals, the metastable alpha form was yielded with well-aligned crystal habits. In contrast, by grinding beta crystals before directional crystallization, the stable beta form was surprisingly produced. These polymorphs were determined using X-ray diffraction, and their differences in photochromic behaviors have been investigated. This study confirms directional crystallization as a novel approach to polymorphic control. It provides a promising method for fabricating well-aligned, shape-specific, and desired polymorphic crystalline materials suitable for device fabrication.

Designing 2D mesoporous metal-organic framework (MOF) nanosheets to overcome the limitations of bulk MOF counterparts, with a focus on enabling smooth mass transport, presents an attractive yet challenging endeavor. Here, a novel bottom-up interface-directed co-assembly method is presented for the synthesis of ultrathin 2D mesoporous UiO-66(Ce) nanosheets. The method utilizes an interface-directed co-assembly of amphiphilic perfluorooctanoic acid-induced lipid bilayers and spherical micelles from PS-b-PEO block copolymers to form unique 2D sandwich-like assemblies that guide the creation of 2D mesoporous UiO-66(Ce). The resultant 2D mesoporous UiO-66(Ce), with ≈23 nm pore diameters and a thickness that can be tuned from 3 to 150 nm, represents a substantial advancement in the application of MOFs for environmental remediation. As a model reaction, the U(VI) photoreduction benefits from the through-mesopores of its 2D morphology, which are absent in previously reported UiO-66(Ce), as they shorten the diffusion path, thereby improving mass transport and accessibility to active sites. This report demonstrates the significant role of existing mesopores in MOFs and the shape control of MOFs.

Photomechanical crystals are fascinating candidates for their applications to light-fueled actuators. Over the past 2 decades diverse examples have been reported. However, research that revealed the structure-photomechanical behavior relationships is rare. Here, we focused on 3 polymorphs of a salicylideneaniline derivative with a 3-carboxy group in the enol form, 1 alpha, 1 beta, and 1 gamma. All polymorphic crystals were stable in air at room temperature and underwent reversible photoisomerization in the solid state. Absorption spectrum measurements revealed that the gamma form, previously considered as nonphotochromic, is weakly photochromic. Upon ultraviolet light irradiation, thin 1 alpha and 1 beta crystals bent away from the light source quickly and slowly, respectively, through photoisomerization while a thin 1 gamma crystal bent toward the illumination direction by the same mechanism. The 1 alpha and 1 beta crystals exhibited high repeatability for photomechanical bending, maintaining their original shape over 100 cycles. In contrast, the 1 gamma crystal gradually deformed during repeated bending because of its plasticity due to the slip planes. Besides the 1 alpha crystal underwent an irreversible thermal phase transition to the 1 beta and 1 gamma crystals upon heating. This work is expected to highlight the relationship between structures and actuation performance, especially bending repeatability, of photomechanical crystals.