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Flexibility has been pursued enthusiastically in the field of porous crystals for enhancing their adsorption and separation performances. However, flexibility has never been observed among porous crystals sustained thoroughly by van der Waals interactions since flexible motions readily lead to the collapse of the porous architecture. Here we report a van der Waals crystal featuring conformational flexibility as well as permanent microporosity. The single-crystal structure and its structural transition in response to the adsorption of water molecules were unambiguously disclosed by means of electron and X-ray crystal structure analyses. The peripheral aromatic rings of the constituent molecule rotated as increasing the ambient humidity, while the connectivity of the pores was maintained throughout the structural transition. The transformative pores allowed the guest water molecules to move exceedingly quickly through the pores with a time constant of 490 μs. We demonstrated that the quick release of water induced by photothermal heating induced a significant upward bending of a film set above the crystalline powder compared to conventional porous materials. This finding contributes to the future crystal engineering based on van der Waals interactions rather than cohesive bonds. Flexibility in porous crystals can enhance their adsorption and separation performances, however, achieving flexibility in porous crystals sustained solely through van der Waals interactions is challenging given that flexible motions typically lead to framework collapse. Here, the authors present a van der Waals crystal that features both conformational flexibility and permanent microporosity [ABSTRACT FROM AUTHOR]

The mitochondrial gene orf108, which is co-transcribed with atp1 and causes cytoplasmic male sterility in Brassica crops, is widely distributed across wild species and genera of Brassicaceae. However, to date, intraspecific variations in the presence of orf108 have not yet been studied, and the mechanisms underlying the wide distribution of the gene remain unclear. We analyzed the presence and sequence variations of orf108 in two wild species, Brassica maurorum and Moricandia arvensis. After polymerase chain reaction amplification of the 5 (0) region of atp1 and the coding sequence of orf108, we determined the DNA sequences. Brassica maurorum and M. arvensis showed variations in the presence of orf108 or orf117 (orf108 (V117)) both between and within accessions and were not fixed to the mitochondrial type with the male sterile genes. Sequencing of the amplicons showed that B. maurorum had orf108 (V117) instead of orf108. Sequencing also indicated mitochondrial heteroplasmy in the two species; in particular, in B. maurorum, one plant possessed both orf108 and orf108 (V117) sequences. These results suggest that substoichiometric shifting of mitochondrial genomes leads to the acquisition or loss of orf108. Furthermore, fertility restorer genes of the two species were involved in the processing of the mRNA of male sterility genes at different sites. Key words: orf108, orf117, intraspecific variation, Brassica maurorum, Moricandia arvensis. Le gene mitochondrial orf108, lequel est co-transcrit avec atp1 et cause l'androsterilite cytoplasmique chez les Brassica cultives, est largement distribue au sein des especes sauvages et divers genres chez les cruciferes. Cependant, a ce jour, aucune etude de la variation intraspecifique quant a la presence de l'orf108 n'a ete realisee et les mecanismes assurant une large distribution de ce gene restent inconnus. Les auteurs ont examine la presence et les variations dans la sequence de l'orf108 chez deux especes sauvages, Brassica maurorum et Moricandia arvensis. Apres amplification PCR de la region 5 (0) du gene atp1 et des sequences codantes de l'orf108, les auteurs en ont realise le sequencage. Au sein de B. maurorum et de M. arvensis, de la variation a ete observee pour la presence des orf108 et orf117 (orf108 (V117)) tant entre les accessions qu'au sein de celles-ci et ces variations n'etaient pas fonction de la presence des genes de sterilite. Le sequencage des amplicons a permis d'etablir que le B. maurorum possede l'orf108 (V117) plutot que l'orf108. Le sequencage a aussi revele une heteroplasmie mitochondriale chez ces deux especes, en particulier chez le B. maurorum ou une plante possedait les deux sequences (orf108 et orf108 (V117)). Ces resultats suggerent que des changements substoichiometriques dans les genomes mitochondriaux menent a l'acquisition ou a la perte de l'orf108. De plus, les genes de restauration de la fertilite chez les deux especes etaient impliques dans la maturation de l'ARNm des genes d'androsterilite a differents sites. Mots-cles : orf108, orf117, variation intraspecifique, Brassica maurorum, Moricandia arvensis., Introduction Cytoplasmic male sterility (CMS) is a phenomenon in which plants fail to produce fertile pollen due to a mitochondrial gene. The phenotypic expression of CMS is suppressed by the [...]

A microsphere, assembled from a chiral π-conjugated polymer with narrow polydispersity, features a well-organized twisted-bipolar structure and exhibits highly biased circularly polarized luminescence (CPL). The CPL emitted toward the equatorial direction is 61-fold greater than that emitted along the zenith direction, which is the highest anisotropy among existing microscopic CPL emitters. [ABSTRACT FROM AUTHOR]

Dragline silk fibers produced by spiders are a masterpiece structural protein that is durable even in the wild conditions. Dragline silk fibers are known to have excellent mechanical toughness and flexibility and further possess optical transparency, which are highly promising as textiles, sensors, and optical devices. Here, the authors show that the dragline silk microfibers act as good optical waveguides with the optical loss coefficient as small as 0.03 decibel per micrometer. The light transportation in the dragline silk fiber is performed by fluorescence energy transfer between two microspheres located on a suspended dragline silk microfiber. By utilizing a micromanipulation equipment, micrometer‐scale spider web‐like structures are fabricated. The experimentally observed optical waveguiding properties of the weaves match well with simulation results using simple mathematical models. Furthermore, optical logic gate operations are demonstrated using photoswitchable microsphere resonators attached on the dragline fibers. [ABSTRACT FROM AUTHOR]

Emission‐switchable fluorophores often include stimuli‐responsive units in their molecular structures. This strategy works well, but the applicable compounds are limited to the derivatives of several kinds of photochromic molecules such as diarylethene, azobenzene, and spiropyran. Here, this work presents a simple methodology based on a photoresponsive precipitant for achieving color‐switchable photoluminescence. A luminescent dye, cyano‐substituted oligo(phenylenevinylene) (COPV), features both twisted intramolecular charge transfer and aggregation‐induced emission shift properties, leading to the change in the luminescence color from green to red upon precipitation. The COPV, together with photoisomerizable precipitant azobenzene (C6), is doped into spherical droplets of epoxy resin (ER) in a liquid state. The photoisomerization of C6 induced by UV irradiation and heating alternatively precipitates out and dissolves COPV in ER and changes the photoluminescence color, while maintaining the optical microresonator properties. This study will open a promising way for assembling/disassembling novel emission color‐switchable systems. [ABSTRACT FROM AUTHOR]