Geometric constraint in pregel solution enables construction of a highly ordered three-dimensional polymer network.

The structure and mechanical properties of model polymer networks consisting of alternating tetra-functional poly(ethylene glycol)s (PEGs) and bis-functional linear PEGs were investigated by dynamic light scattering and rheological measurements. The sizes of the correlation blob (ξc) and the elastic blob (ξel) were obtained from these measurements and compared to the theoretical mesh size, the geometric blob (ξg), calculated by using the tree-like approximation. By fixing the concentration of tetra-PEGs and tuning the molecular weight of linear-PEGs, we systematically compared these blob sizes in two cases: complete network (Case A) and incomplete network (Case B). The correlation blob, ξc, obtained by dynamic light scattering (DLS) was found to obey the well-known concentration dependence for polymer solutions in semidilute regime (ξc~ϕ−3/4) irrespective of the Cases. On the other hand, the G′ was strongly dependent on the Cases: For Case A, G′ was weakly dependent on the molecular weight of linear-PEGs (G′~Mc0.69) while G′ for Case B was a strong increasing function of Mc (G′~Mc1.2). However, both of them are different from the geometric blob (theoretical mesh) of the gel networks. In addition, interesting relationships between G′ and ξc, G′~ξc, G′~ξC−2, were obtained for Cases A and B, respectively.

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The Weiss Functional Impairment Rating Scale Self-Report has been translated into nine languages and has been widely used in assessing functional impairment of adults with ADHD. This study is a psychometric validation of the WFIRS-S in Japanese. The WFIRS-S-J and other questionnaires were administered to 46 adults with attention-deficit-hyperactivity disorder (ADHD), 104 control adults, and 889 university students. ADHD diagnoses were made using the Japanese semi-structured diagnostic interview for adult ADHD, which is compatible with the DSM-5. All subscales of the WFIRS-S-J had Cronbach's α values of around 0.80. Total scores on the WFIRS-S-J had high test-retest reliability after a 2-week interval. The total score, subscale scores, and 59 of the individual item scores of the 70 items in the WFIRS-S-J were significantly higher in the ADHD group than in the other two groups, although more than half of the items in subdomain G (risk) showed floor effects and did not reach significance. Generally WFIRS-S-J subdomain scores were moderately correlated with scores on the Japanese version of Conners' Adult ADHD Rating Scales Self-Report subscales. WFIRS-S-J scores were also correlated (albeit more weakly; 0.31 ≤ r ≤ 0.55) with Beck Depression Inventory II total scores. The WFIRS-S-J showed acceptable psychometric properties, although further study is necessary.

Gels are giant single molecules that consist of a very large number (∼Avogadro's number) of cross-linked nanometer-size polymer chains. Unlike most low-molecular-weight compounds, the extensively crosslinked gel networks typically do not exhibit a well-defined structure. In a previous study, we disproved this preconception and demonstrated that by applying suitable percolation conditions during the gelation process, a highly homogeneous gel with an ordered structure can be synthesized. In the present study, we further demonstrate that by tuning the percolation conditions, stable polymer-rich or polymer-poor nanodefects can be selectively introduced in the gel network; the controlled addition of such nanodefects has not been achieved before. The successful introduction of nanodefects was confirmed using laser speckle tests, and their structures and dynamics were evaluated in Fourier space using static and dynamic scattering measurements. While the addition of polymer-rich defects had a relatively little effect on the elastic modulus of gels, the addition of pores significantly lowered the elastic modulus, suggesting that substantial topological defects were introduced simultaneously when the packing ratio was low. The controlled addition of such nanodefects may potentially modulate the structural, mechanical, optical, and mass transportation properties of the gels effectively, and thus serve as a new design strategy for gel materials.