Gapless superconductivity in overdoped Hg System; Cu-NQR study

The nuclear quadrupole resonance (NQR) investigation of Cu in the overdoped compounds HgBa₂CuO_y (Hg1201) with y=4. 06 (T_c=92K) and 4.11 (64K) and HgBa₂CaCu₂O_y (Hg1212) with y=6.13 (T_c=125K) and 6.21 (117K) was carried out in zero field. From the temperature (T) dependence of the nuclear spin-lattice relaxation time, T₁, of⁶³Cu, we discuss a cause of the T_c suppression with decreasing the number of CuO₂ layers.     

Interpenetrating polymer networks of poly(N-vinylacetamide) and stimuli responsive polymers applied to novel amphiphilic gel

The swelling behaviors of IPN with poly(N-vinylacetamide) (PNVA), which possibly converts from nonionic gel to cationic gel, and the stimuli responsive polymers, such as poly(acrylic acid) (PAAc) and poly(N-isopropylacrylamide) (PNIPAm) were investigated in order to prepare the stimuli responsive amphiphilic gel. When the monomer concentrations were uniformed at the IPN preparation, the obtained PNVA/PAAc IPN showed the pH responsivity with around 100 of swelling ratio at pH 4 to around 1 of swelling ratio at pH 2, although it lost the amphiphilicity due to the lack of swelling in ethanol. On the other hand, the gelation of N-vinylacetamide at 2 M in PNIPAM gel resulted in thermosensitive and amphiphilic hydrogel, that the swelling ratio in EtOH/water (3/7, v/v) also decreased, compared to the value in water at 25 degrees C.     

Fusion of porous isotactic poly(methyl methacrylate) thin films fabricated on silica nanoparticles with stepwise stereocomplex assembly

Structures of silica nanoparticles coated with stereocomplex thin films composed of isotactic (it) poly(methyl methacrylate) (PMMA) and syndiotactic (st) poly(methacrylic acid) (PMAA) and with porous it-PMMA thin films under gentle stirring or static conditions were analyzed by dynamic light scattering (DLS) and scanning electron microscopy (SEM), respectively. The porous it-PMMA films were fabricated by stepwise stereocomplex assembling of it-PMMA and st-PMAA, and subsequent extraction of the st-PMAA from the films. From DLS results, an evident difference was not observed between the it-PMMA films and the stereocomplex films, whereas the it-PMMA films after 10 h of stirring in acetonitrile/water (4/6, v/v) and drying on a SEM stage fused to form nanostructured networks. The fusion of the it-PMMA films on the silica nanoparticles occurred not by the dissolution of it-PMMA in the mixed solvent, but rather by an interaction of the it-PMMA chains driven by the slight solvation of acetonitrile without dissolution. Thus, leaving the solution at rest would be important for film fusion on the particles, and multiple spherical substrates could promote the crosslinking of the it-PMMA chains on the particles.     

Magnetisation of bulk Mn11Si19 and Mn4Si7

The purpose of this paper is to determine by experiment whether Mn₁₁Si₁₉ and Mn₄Si₇ in their bulk states have a finite magnetic moment or not. Magnetisation measurements were carried out on these materials using both SQUID system and Kerr rotation system. The high quality samples were grown using the temperature gradient solution growth method. SQUID measurements revealed that Mn₁₁Si₁₉ has finite magnetism while Mn₄Si₇ does not in their bulk states. It was also confirmed that Mn₄Si₇ became magnetic and Mn₁₁Si₁₉ got to exhibit a distinctive hysteresis in their powdery state. The enhancement of magnetism implied that the surface of the samples was to a great extent linked to its magnetism.     

Cell-junctional and cytoskeletal organization in mouse blastocysts lacking E-cadherin

Trophectoderm epithelium formation, the first visible differentiation process during mouse embryonic development, is affected in embryos lacking the cell adhesion molecule E-cadherin. Here we analyze the developmental potential of such E-cadherin-negative embryos, focusing on the organization of cell junctions and the cytoskeleton. To do this we used antibodies directed against alpha-, beta-, or gamma-(plakoglobin)-catenin and junctional and cytoskeletal proteins including ZO-1 and occludin (tight junctions), desmoglein1 (desmosomes), connexin43 (gap junctions), and EndoA (cytokeratin intermediate filaments). Membrane localization of alpha- and beta-catenin, and ZO-1, as well as cortical actin filament organization were abnormal in E-cadherin-negative embryos, and the expression levels of alpha- and beta-catenin were dramatically reduced, all suggesting a regulatory role for E-cadherin in forming the cadherin-catenin complex. In contrast, the membrane localization of plakoglobin, occludin, desmoglein1, connexin43, and cytokeratin filaments appeared unaltered. The unusual morphogenesis in E-cadherin-negative embryos apparently reflects defects in the molecular architecture of a supermolecular assembly involving zonulae adherens, tight junctions, and cortical actin filament organization, although the individual structures still appeared normal in electron microscopical analysis.     

Development of a total internal reflection ultrafast transient lens method for studying molecular dynamics on an interface

We have developed the total internal reflection ultrafast transient lens (TIR-UTL) method to detect nonradiative chemical processes at interfaces and surfaces with subpicosecond time resolution. In the TIR-UTL measurements, the evanescent field of a pump beam irradiated under the TIR condition generates a refractive index change. The refractive index change is attributed to changes of the molecular electronic state, of density by molecular orientation/structure change, and of temperature by vibrational relaxation processes. The refractive index change is detected as a change of the power intensity of the probe beam adjusted coaxially with the pump beam. At first, we discuss a theoretical principle of a coaxial configuration in the TIR-UTL measurement. This configuration has an advantage of versatility over the established TIR configuration. Then, we evaluate time resolution of TIR-UTL and obtain a value of less than 400 fs. We measure the ultrafast molecular dynamics of the cationic chromophore Auramine O (AuO) at a silica/water interface. Two slow time constants originating from AuO adsorbed on the silica surface are detected by TIR-UTL. These are attributed to AuO, whose twisting motion is strongly hindered by adsorption on a silica surface.     

In Vitro Cytological Responses against Laser Photobiomodulation for Periodontal Regeneration

Periodontal disease is a chronic inflammatory disease caused by periodontal bacteria. Recently, periodontal phototherapy, treatment using various types of lasers, has attracted attention. Photobiomodulation, the biological effect of low-power laser irradiation, has been widely studied. Although many types of lasers are applied in periodontal phototherapy, molecular biological effects of laser irradiation on cells in periodontal tissues are unclear. Here, we have summarized the molecular biological effects of diode, Nd:YAG, Er:YAG, Er,Cr:YSGG, and CO₂ lasers irradiation on cells in periodontal tissues. Photobiomodulation by laser irradiation enhanced cell proliferation and calcification in osteoblasts with altering gene expression. Positive effects were observed in fibroblasts on the proliferation, migration, and secretion of chemokines/cytokines. Laser irradiation suppressed gene expression related to inflammation in osteoblasts, fibroblasts, human periodontal ligament cells (hPDLCs), and endothelial cells. Furthermore, recent studies have revealed that laser irradiation affects cell differentiation in hPDLCs and stem cells. Additionally, some studies have also investigated the effects of laser irradiation on endothelial cells, cementoblasts, epithelial cells, osteoclasts, and osteocytes. The appropriate irradiation power was different for each laser apparatus and targeted cells. Thus, through this review, we tried to shed light on basic research that would ultimately lead to clinical application of periodontal phototherapy in the future.     

Controlled DNA interpolyelectrolyte complex formation or dissociation via stimuli‐responsive poly(vinylamine‐co‐N‐vinylisobutylamide)

Poly(vinylamine‐co‐N‐vinylisobutylamide) or poly(VAm‐co‐NVIBA) was evaluated for its ability to stabilize double‐stranded DNA (dsDNA) with the controlled formation or dissociation of polyion complexes. The poly(VAm‐co‐NVIBA) copolymer consists of the cationic poly(vinylamine) (VAm) that electrostatically binds to the anionic DNA and the thermally responsive poly(N‐isobutylamide) (NVIBA) that helps limit the strength of the electrostatic interaction and prevents the alteration of the DNA helical structure. Agarose gel electrophoresis showed the successful complexation between dsDNA and poly(VAm‐co‐NVIBA). Moreover, DNA was released from the complex at 65 °C, but not at 25 °C. Thus, the NVIBA component in the copolymer played an important role in controlling the process of complex formation or dissociation according to the pH and temperature. The results showed that the molecular design of polycations with a thermoresponsive part is a potential strategy to allow the controllable formation and dissociation of the copolymer/dsDNA complex while avoiding changes to the DNA helical structure. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43852.