Simultaneous Edge‐on to Face‐on Reorientation and 1D Alignment of Small π‐Conjugated Molecules Using Room‐Temperature Mechanical Rubbing

In this study, room‐temperature mechanical rubbing is used to control the 3D orientation of small π‐conjugated molecular systems in solution‐processed polycrystalline thin films without using any alignment substrate. High absorption dichroic ratio and significant anisotropy in charge carrier mobilities (up to 130) measured in transistor configuration are obtained in rubbed organic films based on the ambipolar quinoidal quaterthiophene (QQT(CN)4). Moreover, a solvent vapor annealing treatment of the rubbed film is found to improve the optical and charge transport anisotropy due to an increased crystallinity. X‐ray diffraction and atomic force microscopy measurements demonstrate that rubbing does not only lead to an excellent 1D orientation of the QQT(CN)4 molecules over large areas but also modifies the orientation of the crystals, moving molecules from an edge‐on to a face‐on configuration. The reasons why a mechanical alignment technique can be used at room temperature for such a polycrystalline film are rationalized, by the plastic characteristics of the QQT(CN)4 layer and the role of the flexible alkyl side chains in the molecular packing. This nearly complete conversion from edge‐on to face‐on orientation by mechanical treatment in polycrystalline small‐molecule‐based thin films opens perspectives in terms of fundamental research and practical applications in organic optoelectronics.     

Enhanced Electroluminescence from Organic Light‐Emitting Diodes with an Organic–Inorganic Perovskite Host Layer

The development of host materials with high performance is essential for fabrication of efficient and stable organic light‐emitting diodes (OLEDs). Although host materials used in OLEDs are typically organics, in this study, it is shown that the organic–inorganic perovskite CH₃NH₃PbCl₃ (MAPbCl₃) can be used as a host layer for OLEDs. Vacuum‐evaporated MAPbCl₃ films have a wide band gap of about 3 eV and very high and relatively balanced hole and electron mobilities, which are suitable for the host material. Photoluminescence and electroluminescence take place through energy transfer from MAPbCl₃ to an organic emitter in films. Incorporation of an MAPbCl₃ host layer into OLEDs leads to a reduction of driving voltage and enhancement of external quantum efficiency as compared to devices with a conventional organic host layer. Additionally, OLEDs with an MAPbCl₃ host layer demonstrate very good operational stability under continuous current operation. These results can be extensively applied to organic‐ and perovskite‐based optoelectronics.     

Stereoregular oligomers of methyl methacrylate

Summary Packed column SFC has been found suitable for the rapid and detailed analysis of the isotactic and syndiotactic oligomers of MMA, when the temperature gradient technique was applied and the modifier was employed. Oligomer components from trimer to 20-mer separated completely. The heptamer fraction collected three times by SFC gave the ¹H NMR spectrum of satisfactorily high S/N ratio; the spectrum agreed well with that of the standard sample. Separation by tacticity as well as by molecular weight was observed for the SFC of a mixture of the isotactic and syndiotactic oligomers. The isotactic oligomers had longer retention time than the syndiotactic oligomers of the corresponding degree of polymerization. Part 3: cf. Ute K. Nishimura T, Hatada K, Polym J (1989) 21: 1027     

Molecular orientation induced by high-speed substrate transfer during vacuum vapor deposition of organic films

The authors investigate a relationship between substrate transfer speeds during vacuum vapor deposition and orientation characteristics of organic molecules. Results show that rod-shaped molecules of alpha-sexithiophene (α-6T) are oriented in a substrate transfer direction and an absorption dichroic ratio of 1.44 is obtained from the oriented α-6T molecule film when a high substrate transfer speed of 4 m s⁻¹ is used. By combining the substrate transfer technique with homoepitaxial growth of α-6T molecules on a rubbed surface, the absorption dichroic ratio further increases to 4.29. Polarized electroluminescence (EL) characteristics are investigated using rod-shaped molecules of 4,4′-bis[4-(di-p-tolylamino)styryl]biphenyl (DPAVBi) as a light-emitting hole-transport layer. An EL dichroic ratio of 2.12 is obtained due to an orientation of DPAVBi molecules caused by combining two techniques.     

New aspects in the unfolding of the nilpotent singularity of codimension three

This paper is concerned with three-dimensional vector fields and more specifically with the study of dynamics in unfoldings of the nilpotent singularity of codimension three. The ultimate goal is to understand the dynamics and bifurcations in the unfolding of the singularity. However, it is clear from the literature that the bifurcation diagram is very complicated and a complete study is far beyond the current possibilities, not only from a theoretical point of view but also from a numerical point of view, despite recent developments of computational methods for dynamical systems. Since all complicated dynamical behaviour is known to be of small amplitude, shrinking to the singularity for parameter values tending to the bifurcation parameter, the aim in this paper is especially to focus on a different aspect that might be interesting in the study of global bifurcation problems in the presence of such a nilpotent singularity of codimension three. The notion is introduced of 'traffic regulator' and the specific sets called the 'inset' and 'outset', which give a new framework for studying a transition map in a cylindrical neighbourhood of the singularity that contains all the non-trivial dynamics that can bifurcate from the singularity, focusing on the domains on which the transition map is defined. A list is also given of open problems which are believed to be helpful for future investigation of the bifurcations from the nilpotent triple zero singularity in 3.     

Establishment of Intestinal Organoid from Rousettus leschenaultii and the Susceptibility to Bat-Associated Viruses,SARS-CoV-2 and Pteropine Orthoreovirus

Various pathogens, such as Ebola virus, Marburg virus, Nipah virus, Hendra virus, Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and SARS-CoV-2, are threatening human health worldwide. The natural hosts of these pathogens are thought to be bats. The rousette bat, a megabat, is thought to be a natural reservoir of filoviruses, including Ebola and Marburg viruses. Additionally, the rousette bat showed a transient infection in the experimental inoculation of SARS-CoV-2. In the current study, we established and characterized intestinal organoids from Leschenault’s rousette, Rousettus leschenaultii. The established organoids successfully recapitulated the characteristics of intestinal epithelial structure and morphology, and the appropriate supplements necessary for long-term stable culture were identified. The organoid showed susceptibility to Pteropine orthoreovirus (PRV) but not to SARS-CoV-2 in experimental inoculation. This is the first report of the establishment of an expandable organoid culture system of the rousette bat intestinal organoid and its sensitivity to bat-associated viruses, PRV and SARS-CoV-2. This organoid is a useful tool for the elucidation of tolerance mechanisms of the emerging rousette bat-associated viruses such as Ebola and Marburg virus.     

O-Glycan-Dependent Interaction between MUC1 Glycopeptide and MY.1E12 Antibody by NMR,Molecular Dynamics and Docking Simulations

Anti-mucin1 (MUC1) antibodies have been widely used for breast cancer diagnosis and treatment. This is based on the fact that MUC1 undergoes aberrant glycosylation upon cancer progression, and anti-MUC1 antibodies differentiate changes in glycan structure. MY.1E12 is a promising anti-MUC1 antibody with a distinct specificity toward MUC1 modified with an immature O-glycan (NeuAcα(2-3)Galβ(1-3)GalNAc) on a specific Thr. However, the structural basis for the interaction between MY.1E12 and MUC1 remains unclear. The aim of this study is to elucidate the mode of interaction between MY.1E12 and MUC1 O-glycopeptide by NMR, molecular dynamics (MD) and docking simulations. NMR titration using MUC1 O-glycopeptides suggests that the epitope is located within the O-linked glycan and near the O-glycosylation site. MD simulations of MUC1 glycopeptide showed that the O-glycosylation significantly limits the flexibility of the peptide backbone and side chain of the O-glycosylated Thr. Docking simulations using modeled MY.1E12 Fv and MUC1 O-glycopeptide, suggest that V_H mainly contributes to the recognition of the MUC1 peptide portion while V_L mainly binds to the O-glycan part. The V_H/V_L-shared recognition mode of this antibody may be used as a template for the rational design and development of anti-glycopeptide antibodies.     

Zeolite nanocrystals prepared from zeolite microparticles by a centrifugation-assisted grinding method

Different sizes of zeolite nanocrystals were fabricated from zeolite microparticles using a centrifugation-assisted grinding method. The zeolite nanocrystal formation can be attributed to the Al₂O₃ bowl mill generation of mechanical stress that fractured zeolite microparticles into smaller fragments. In the present study, the smaller fragments had a wide distribution of size and morphology. Therefore, different sizes of zeolite nanocrystals could be recovered from these smaller fragments by varying the centrifugation process. Zeolite nanocrystal product yields were measured by periodically recovering the nanocrystals from the smaller fragments based on milled zeolite powder. The larger crystals of zeolite were typically irregular in shape, whereas the smaller zeolite nanocrystals tended to be spherical. High product yield of the zeolite nanocrystals was obtained by periodically removing nanocrystals from the milled zeolite powder and recycling the large zeolite particles. Thus, the results from this new hybrid process suggest that it can be used to fabricate differing sizes of zeolite nanocrystals. In addition, the size of the recovered zeolite nanocrystal products was narrow, and the initial zeolite nanocrystal structure was not destroyed by the mechanical stress.