Thermo- and pH-responsive gels for application in colon delivery systems

Swelling-controlled drug delivery copolymer gels were synthesized by introducing thermo- and pH-responsive methacryloyl-glycine (MA-Gly) of pH-responsive methacrylic acid (MA-Ac) into thermo-responsive acryloyl- -proline ethyl ester (A-ProOEt). The threshold of swelling for copolymer gels consisting of A-ProOEt/MA-Gly and A-ProOEt/MA-Ac with a composition of 40/60 mol% was found to be pH 3.0 and pH 5.5, respectively, in buffer solutions at 37°C. The diffusion characteristics of 2-(3-benzoylphenyl)propionic acid (ketoprofen) from such copolymer gels were evaluated in buffer solutions at pHs more than 5.5, and it was found that A-ProOEt/MA-Gly gel possessed a Case II transport, while the A-ProOEt/MA-Ac gel exhibited a non-Fickian (or anomalous) diffusion behavior under the same conditions.     

Initiation gait variability is higher in the morning in elderly inpatients

Objective: Although elderly inpatients are known to experience decreased physical activity in the morning, falls occur frequently during this time. Gait variability is an evaluation of gait instability and a risk factor for falls. Gait initiation requires complex processes, and it is important to evaluate gait variability not only during steady-state gait but also during gait initiation. However, the effect of the diurnal pattern on variability in gait characteristics is still unknown. The aim of this study was to investigate the effect of the diurnal pattern on initiation and steady-state gait variability in elderly inpatients. Method: Thirty-seven elderly inpatients (28 women; mean age, 79.7 ± 9.5 years) who could walk without support were sampled in this study. The quantitative measure of gait variability was evaluated using the coefficient of variation (CV) based on four consecutive stride durations determined using triaxial accelerometers. Gait characteristics were evaluated during initiation and steady-state gait and defined as initiation CV and steady-state CV, respectively. This measurement was performed at two time points, morning and daytime. Results: There was no significant difference between initiation and steady-state gait characteristics in the daytime condition. However, in the morning condition, the initiation CV was higher than the steady-state CV. Furthermore, the initiation CV was higher in the morning than during daytime (p < 0.01). Conclusion: Our study revealed that the variability of initiation gait is higher in the morning. It may be important to assess the risk of falls, including initiation gait, in the morning.     

Lewis-Pairing-Induced Electrochemiluminescence Enhancement from Electron Donor-Acceptor Diads Decorated with Tris(pentafluorophenyl)borane as an Electrochemical Protector

This study reports an effective peripheral decoration of organic donor-acceptor diads with B(C₆F₅)₃ for stabilizing electrogenerated radical ions. By employing a common p-type organic semiconductor benzothienobenzothiophene (BTBT) as the donor, tetracoordinate boron complexes showed improved solution electrochemiluminescence (ECL) intensity, reaching a 156-fold increase compared to that of the parent diad. The unprecedented Lewis-pairing-induced ECL enhancement is attributed to the multiple roles of B(C₆F₅)₃: 1) redistributing frontier orbitals, 2) facilitating electrochemical excitation, and 3) restricting molecular motions. Furthermore, B(C₆F₅)₃ converted the molecular arrangement of BTBT from conventional 2D herringbones into 1D π-stacks. This robust, highly ordered columnar nanostructure allowed red-shifting of the crystalline film ECL with electrochemical doping through the electronic coupling pathways of BTBT. Our approach will facilitate the development of elaborate metal-free ECL systems.     

Impedance Effect on Ion Transport in a Temperature‐Sensitive Gel Membrane

The impedance effect on the ion transport of lithium chloride through temperature‐ and pH‐sensitive gel membranes was investigated. Both conductance and loss tangent show a relatively high value at temperatures near the lower critical solution temperature (14°C), followed by an abrupt drop with a further rise in temperature. The Figure shows an example of changes in absolute complex conductance (Y ), real conductance (G ), and imaginary conductance (B) for a poly(acryloyl‐L ‐proline methyl ester) gel membrane.