Poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) exhibits a phenomenon known as co-nonsolvency in certain alcohol/water binary mixtures. We have exploited this phenomenon to prepare a series of sterically stabilized PMPC nanolatexes by atom transfer radical polymerization (ATRP) under dispersion polymerization conditions using a near-monodisperse poly(ethylene oxide) (PEO) macroinitiator in a 9:1 isopropanol/water mixture. The as-synthesized nanolatex particles comprised nonsolvated PMPC cores and solvated PEO shells, as determined by 1H NMR spectroscopy. In our preliminary experiments linear core-forming PMPC chains were targeted, but alternatively either ethylene glycol dimethacrylate or bisphenol A dimethacrylate can be used as comonomers (at up to 10 mol % based on MPC) in order to prepare cross-linked PMPC particles that acquire swollen microgel character when dialyzed against pure water. Low levels of cross-linker (e.g., 4 mol %) lead to bimodal microgel size distributions as judged by dynamic light scattering. However, higher levels of cross-linker (e.g., 10 mol %) lead to narrow unimodal microgel size distributions, since all the core-forming PMPC chains become cross-linked. The final nanolatex/microgel dimensions are dictated by the target block compositions and initial MPC concentration used in these ATRP syntheses. A PEO113-b-PMPC50 formulation synthesized at 30 wt % solids produced nanolatex/microgel particles that were 5−6 times larger than those observed for the same block composition prepared at 10 wt % solids. TEM and SEM studies confirm that these new sterically stabilized particles have uniform spherical morphologies. Cross-linked PEO-b-PMPC particles were analyzed by X-ray photoelectron spectroscopy after dialysis against water. The surface coverage of the PEO stabilizer chains was estimated to be 54−61%. Aqueous electrophoresis studies confirmed that the PEO-b-PMPC microgels exhibited almost zero net charge, and the addition of electrolyte had little effect on their dimensions and colloidal stability due to the anti-polyelectrolyte behavior expected for the zwitterionic PMPC chains.

Objectives The aim of this study was to investigate whether the newly developed artificial dental plaque (A‐DP) is useful as an educational tool for denture care of dental hygienist that compared it with conventional artificial dental plaque from the viewpoint of practical skills. Material and methods The 125 dental hygienist school students and 26 dental hygienists who had clinical experience were subjected a practical training of denture plaque control using the conventional denture plaque (C‐DP) and the A‐DP. The questionnaires based on the semantic differential method were used to survey whether the A‐DP is similar to the real denture plaque (R‐DP). Factor analysis by rotation of promax was carried out. Results In the results of the factor analysis, the two factors could be detected in students and three factors in dental hygienists. The total score of each denture plaque was calculated for each factor, and correlation coefficient was examined. There was significant correlation between the A‐DP and the R‐DP at the first factors, both students and dental hygienists. C‐DP was not similar to R‐DP in all factors. Conclusions These results suggested that A‐DP resembles R‐DP better than C‐DP. It was concluded that the A‐DP was similar to the R‐DP and could be a potent educational tool for practical denture care.

Summary: We report the case of a 71-year-old man who was experiencing a gradually worsening, dull pain and a cold sensation in his right hand. Three months earlier, he underwent a percutaneous coronary intervention for angina pectoris using a transradial approach in his right wrist and developed an arteriovenous fistula (AVF), a complication of percutaneous coronary intervention. Ultrasonography and computed tomography revealed a pseudoaneurysm and an AVF that were reducing the blood flow in his right hand. We observed that the pseudoaneurysm and the AVF were close to the bifurcation of the superficial palmar artery (SPA) and that the superficial palmar arch had radial artery superiority. Because we thought it was important to maintain the blood flow of the SPA branch, we excised the pseudoaneurysm, sutured the artery directly via microsurgery, and ligated the arteriovenous shunt. After the operation, the patient’s symptoms were alleviated. Computed tomography showed that the blood flow in his right hand was improved and that his right SPA branch from the radial artery was directly fed to the index finger. Because the blood circulation in the hand is dual dominant but with many anatomical variations, we believe that it is important to preserve the blood flow of the SPA in postcatheterization pseudoaneurysm and AVF repair.

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