Chiral conglomerates of domains with opposite handedness have attracted much attention from researchers. We prepared a homologous series of achiral liquid crystal trimers in which two ...phenylpyrimidine units and one biphenyl unit were connected via flexible methylene spacers. We investigated their phase transition behaviour. Some trimers possessing odd-numbered spacers were found to exhibit a nematic phase and a dark chiral conglomerate phase possessing a layered structure. The chiral characteristics were confirmed by uncrossing the polarizers in opposite directions. The layer spacing detected using X-ray diffraction was about 80% of the molecular length. The structure-property relations indicate that intermolecular interactions cause a conformational change in the trimers possessing flexible odd-numbered methylene spacers to form helical conformers with axial chirality, which might induce chiral segregation and layer deformation to drive the chiral conglomerates.
Chiral conglomerate phases have attracted much attention not only for the spontaneous mirror symmetry breaking but also for their nanostructures. We investigated both surface and bulk structures of a ...homologues series of an achiral liquid crystal trimer I-(n,m) exhibiting soft crystalline chiral conglomerate phases by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The trimers were found to form bicontinuous networks. In particular, trimer I-(9,9) exhibited a single gyroid-like surface accompanying periodic distribution of dimples with a size of about 100 nm. It showed a sponge-like structure in the bulk of the material. The twist conformation of the flexible trimer I-(n,m) can cause layer deformation, which produces bicontinuous networks exhibiting optical activity.
We prepared a homologous series of achiral liquid crystal trimers (I-n) in which two phenylpyrimidine units and one biphenyl unit were connected via flexible spacers, and investigated the physical ...properties. All the trimers possessing odd-numbered methylene spacers exhibited soft crystalline chiral conglomerate phases. X-ray diffraction measurements reveal that they have an intercalated layer structure. On the other hand, the trimers possessing even-numbered spacers showed nematic and smectic C phases. We investigated the surface structures of odd-membered trimers in the soft crystalline phases using scanning electron microscopy. Trimers I-3 and I-5 were found to form cylindrical tubes, whereas trimers I-7, I-9 and I-11 toroidal pits. We discuss the formation of diverse supramolecular architectures in terms of the anisotropy of the chirality transfer.
A mild deacylation method for 3,5-dinitrobenzoates using methanolic solutions of amines, such as dialkylamines, was developed. The method’s versatility was confirmed by applying it to synthesizing a ...key intermediate for Colorado potato beetle pheromone.
Dark conglomerates of domains with opposite handedness, which are designated dark conglomerate phases (DC phases), have attracted much attention. We prepared an achiral liquid crystal trimer, ...4,4′-bis{9-4-(5-octyloxypyrimidin-2-yl)phenyloxynonyloxy}biphenyl (I–9), and investigated the physical properties. A droplet of trimer I–9 formed a conventional nematic phase on cooling from the isotropic liquid, and then changed to an optical isotropic phase with homochirality. X-ray diffraction measurements reveal that the isotropic phase has an intercalated layer structure with a correlation length of 95 nm. We prepared binary mixtures with a nematic liquid crystal, 4′-hexyloxy-4-cyanobiphenyl (6OCB). The mixtures containing 30–75 mol % of 6OCB exhibited smectic phases above the isotropic phase. We investigated mesogenic properties of trimer I–n (n = 5–9) depending on the parity of the linking group. Only trimer I–9 possessing the longest odd-numbered spacers showed the chiral isotropic phase, suggesting that a rigid bent structure is not necessary for the appearance of the isotropic phase. The experimental results reveal that trimer I–9 exhibits a soft crystalline DC phase representing a new modification of chiral symmetry breaking in lamellar liquid crystal phases.
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IJS, KILJ, NUK, PNG, UL, UM
Acanthamoeba is one of the organisms that cause corneal infection. In this study, attention was focused on potassium isostearate (iso-C18K, a branched chain fatty acid salt) for use in a multipurpose ...solution (MPS) against Acanthamoeba. An anti-amoebic test against Acanthamoeba castellanii ATCC 30010 (trophozoites type) was conducted. As a result, a growth reduction effect of 4 log units (99.99% suppression) was observed after incubation with 150 mM (5.0 w/v%) iso-C18K for 10 minutes. Furthermore, after the amoeba suspension was mixed with iso-C18K, disruption of cell membranes were observed, and the minimum amoebacidal concentration (MAC) at that time was 9.6 mM (0.31 w/v%). To evaluate the effectiveness as an MPS, assessment by verification tests was conducted using contact lenses. Reducing the concentration of iso-C18K caused a decrease in the number of viable cells, which was confirmed at a MAC of 1.2 mM (0.039 w/v%).
Dark conglomerates of domains with opposite handedness, which are designated as dark conglomerate phases (DC phases), have attracted much attention. After designing an achiral liquid crystal trimer, ...4,4′-bis{7-4-(5-octyloxypyrimidin-2-yl)phenyloxyheptyloxy}biphenyl (1), which exhibits only a nematic phase, we prepared binary mixtures with some typical rod-like nematic liquid crystals, i.e., 4′-hexyloxy-4-cyanobiphenyl (6OCB), 2-(4-hexyloxyphenyl)-5-pentyloxypyrimidine (PPY), or 4-methyloxyphenyl 4-hexyloxycyclohexanecarboxylate (PCA), and investigated their phase transition behaviour. The binary mixtures containing 55–90 mol% of 6OCB were found to exhibit a nematic phase and a DC phase of chiral domains with opposite handedness. However, neither PPY nor PCA induced such a chiral conglomerate phase in the mixture with trimer 1. We discuss how core–core interactions contribute to produce such a chiral conglomerate phase.
Blood–brain barrier (BBB) dysfunction is a key feature in neuroimmunological and neurodegenerative diseases. In this study, we developed a microfluidic human BBB-on-a-chip to model barrier ...dysfunction and immune cell migration using immortalized TY10 brain endothelial cells, pericytes, and astrocytes. It was found that immortalized TY10 brain endothelial cells developed a microvascular structure under flow. Pericytes were localized on the basal side surrounding the TY10 microvascular structure, showing an in vivo-like structure. Barrier integrity increased under co-culture with pericytes. In addition, both ethylenediaminetetraacetic acid (EDTA) and anti-Claudin-5 (CLDN5) neutralizing antibody caused a decrease in the transendothelial electrical resistance (TEER). EDTA caused the leakage of 20 kDa dextran, suggesting different effects on the BBB based on the mechanism of action, whereas anti-CLDN5 antibody did not cause leakage. In the tri-culture model, human T cells migrated through endothelial vessels towards basal C-X-C motif chemokine ligand 12 (CXCL12). The live-imaging analysis confirmed the extravasation of fluorescence-labelled T cells in a CXCL12-concentration- and time-dependent manner. Our BBB model had an in vivo-like structure and successfully represented barrier dysfunction and transendothelial T cell migration. In addition, our study suggests that the inhibition of CLDN5 attenuates the BBB in humans. This platform has various potential uses in relation to the BBB in both drug discovery research and in elucidating the mechanisms of central nervous system diseases.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Pregnancy and puerperium are at increased risk of venous thromboembolism（VTE）, including deep vein thrombosis（DVT）and pulmonary thromboembolism（PTE）. In case 1 who developed VTE in the first ...trimester of pregnancy, an inferior vena cava（IVC）filter was temporarily placed due to coexistence of PTE, but the IVC filter could be removed after anticoagulant therapy, and vaginal delivery was successful. In case 2 who developed VTE in the third trimester of pregnancy, labor has onset before confirming the disappearance of the iliac vein DVT, and the temporary IVC filter was placed immediately before vaginal delivery. Since the mechanism of VTE onset and the time to delivery are different between the first trimester and third trimester, management of DVT, such as IVC filter placement, is also different during each pregnancy period.
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