Hybrid EuIII Coordination Luminophore Standing on Two Legs on Silica Nanoparticles for Enhanced Luminescence

In this study, we have demonstrated a two-legged, upright molecular design method for monochromatic and bright red luminescent Ln^III-silica nanomaterials. A novel Eu^III-silica hybrid nanoparticle was developed by using a doubly binding TPPO−Si(OEt)₃ (TPPO: triphenyl phosphine oxide) linker. The TPPO−Si(OEt)₃ was confirmed by ¹H, ³¹P, ²⁹Si NMR spectroscopy and single-crystal X-ray analysis. Luminescent Eu(hfa)₃ and Eu(tfc)₃ moieties (hfa: hexafluoroacetylacetonate, tfc: 3-(trifluoromethylhydroxymethylene)camphorate) were fixed onto TPPO−Si(OEt)₃-modified silica nanoparticles, producing Eu(hfa)₃(TPPO−Si)₂-SiO₂ and Eu(tfc)₃(TPPO−Si)₂-SiO₂, respectively. Eu(hfa)₃(TPPO−Si)₂−SiO₂ exhibited the higher intrinsic luminescence quantum yield (93 %) and longer emission lifetime (0.98 ms), which is much larger than those of previously reported Eu^III-based hybrid materials. Eu(tfc)₃(TPPO−Si)₂−SiO₂ showed an extra-large intrinsic emission quantum yield (54 %), although the emission quantum yield for the precursor Eu(tfc)₃(TPPO−Si(OEt)₃)₂ was found to be 39 %. These results confirmed that the TPPO−Si(OEt)₃ linker is a promising candidate for development of Eu^III-based luminescent materials.     

Area‐selective microwrinkle formation on poly(dimethylsiloxane) by treatment with strong acid

Microwrinkles were formed by treating poly(dimethylsiloxane) (PDMS) surfaces with a mixture of concentrated sulfuric acid and nitric acid at 80 °C followed by a water rinsing step. The acid treatment oxidized the treated area, which also swelled owing to absorption of water during the rinsing step. This absorption of water induced a compressive stress on the PDMS surface that caused the formation of wrinkles. The appearance of wrinkles was controlled by the time interval between the end of the acid treatment and the beginning of the water rinsing step. Wrinkles were formed when the time interval was shorter than 5 s, as water was absorbed by the hygroscopic acid molecules within the treated surface. For longer time intervals of 300 s, this phenomenon was not observed. Based on these findings, a procedure for forming wrinkles in specific areas was developed by hydrating the chosen areas with wet filter paper cut into specific shapes after the acid treatment. The formation of wrinkles was confined to the area under the piece of paper. The orientation and alignment of the wrinkles at the boundaries were also characterized. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 167–174     

Copper‐Free Huisgen Cycloaddition for the 14‐3‐3‐Templated Synthesis of Fusicoccin‐Peptide Conjugates

Mid‐sized molecules have emerged as an attractive chemical space and potentially provide a robust basis for the development of synthetic agents to control intracellular protein interactions. However, the limited cell permeability and chemical tractability of such agents remain to be addressed. We envisioned that target‐templated synthesis of such mid‐sized molecules might provide a solution. Here, we exploited a copper‐free Huisgen cycloaddition for template synthesis using a peptide fragment containing a 4,8‐diazacyclononyne (DACN) moiety and an azide‐containing fusicoccin derivative in the presence or absence of recombinant 14‐3‐3ζ protein in vitro. Time‐course changes in the yield of products demonstrated that the reaction was accelerated in the presence of 14‐3‐3 and one of the regioisomers was generated predominantly, supporting the template effect.     

The effect of neuromuscular electrical stimulation on muscle EMG activity and the initial phase rate of force development during tetanic contractions in the knee extensor muscles of healthy adult males

Objective: Neuromuscular electrical stimulation (NMES) has been noted as an effective pre- contraction for an increase of neural and muscle factors during twitch contractions. However, it is unknown if this intervention is effective for the rate of force development (RFD), which is the ability to increase joint torque strength as quickly as possible, during tetanic contractions. NMES can be safely used by anyone, but, the strength setting of NMES requires attention so as not to cause pain. Therefore, the purpose of this study investigated whether NMES at less painful levels was effective for RFD during tetanic contractions. We also investigated effect activation by analyzing electromyogram (EMG) and RFD for each phase. Methods: Eighteen healthy males were studied. Before and after NMES intervention at 10% or 20% maximal voluntary isometric contraction (MVIC) level (10%NMES, 20%NMES respectively), EMG activity and the initial phase (30-, 50-, 100-, and 200-msec) RFD were measured. Visual analog scale (VAS) was also measured as an indicator of pain during each NMES. Results: 20%NMES increased EMG activity and 30-, 50-, and 100-msec of RFD during MVIC, but could not improve 200 msec of RFD. However, 10%NMES could be failed to increase all phases RFD, but VAS was lower than that of 20% NMES. Conclusion: These results suggest that muscle pre-contraction using 20%NMES could induce moderate pain, but could be an effective intervention to improve RFD via neural factor activity.     

A new organic superconductor beta-(meso-DMBEDT-TTF)2PF6

A newly synthesized donor meso-DMBEDT-TTF [DMBEDT-TTF = 2-(5,6-dihydro-1,3-dithiolo[4,5-b][1,4]dithiin-2-ylidene)-5,6-dihydro-5,6-dimethyl-1,3-dithiolo[4,5-b][1,4]dithiin] afforded a superconducting salt beta-(meso-DMBEDT-TTF)2PF6, with a transition temperature at 4.3 K (onset) under a hydrostatic pressure of 4.0 kbar.