Acid/Flux Brush, Tin Ferrule, Horsehair, 5-3/4" Length, 5/16" Width(Pack of 30 Pieces)

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In this study, we functionalized the surface of planar lipid membranes ( i.e., supported membranes) 22,23 with poly(acrylic acid) brushes bearing cysteine side chain functional groups (pAA-Cys) by incorporating the lipids covalently coupled with pAA-Cys ( i.e., DOPE-pAA-Cys5) into the matrix lipids ( Fig. 1). In these materials, pAA-Cys5 moieties interact with divalent Cd 2+ ions similar to naturally occurring proteins 24 because pAA-Cys has both –SH and –COOH groups. We investigated how pAA-Cys brushes adapt their structure and mechanical landscape near the interface following the addition of Cd 2+ ions. We used lipids and lipopolymers with identical hydrocarbon chains to prevent phase separation. 25 The lateral average distance between lipopolymer molecules 〈 d〉 can be precisely controlled by taking advantage of the self-assembling nature of lipids and lipopolymers and tuning the molar fraction of lipopolymers χ lipo, such that A 2013 national survey [footnote 2] found that only a quarter of children benefited from having their teeth brushed before they were 6 months of age, whereas about 50% had commenced between 6 months and one year of age. Overall about 90% of children (aged 5 to 8 years) are reported as having started toothbrushing by 2 years of age [footnote 2]. Overall, 77% of 12-year-olds and 81% of 15-year-olds reported that they brushed their teeth twice daily or more. Mouthwash was the most common aid other than a toothbrush (manual or powered) and toothpaste. As expected, the use of mouthwashes, dental floss (the only interdental cleaning method investigated) and sugar-free gum was generally higher in older children. Approximately 40% of the school children surveyed used a powered toothbrush. Oral hygiene principles for oral health T. Ikarashi, T. Yoshino, N. Nakajima, K. Miyata, K. Miyazawa, Y. Morais Jaques, A. S. Foster, M. Uno, C. Takatoh and T. Fukuma, ACS Appl. Nano Mater., 2020, 4, 71–83 CrossRef. clean all tooth surfaces, and the gum line, thoroughly with a toothbrush and fluoride-containing toothpaste at least twice a day (last thing at night or before bed and one other time), spitting out the excess toothpaste

N. D. Spencer and W. T. Tysoe, The Cutting Edge of Tribology, World Scientific Publishing, 2015 Search PubMed. J. Czajor, W. Abuillan, D. V. Nguyen, C. Heidebrecht, E. A. Mondarte, O. V. Konovalov, T. Hayashi, D. Felder-Flesch, S. Kaufmann and M. Tanaka, RSC Adv., 2021, 11, 17727–17733 RSC. A. Yamamoto, K. Hayashi, A. Sumiya, F. Weissenfeld, S. Hinatsu, W. Abuillan, M. Nakahata and M. Tanaka, Front. Soft Matter, 2022, 2, 959542 CrossRef.Y. Higaki, B. Frohlich, A. Yamamoto, R. Murakami, M. Kaneko, A. Takahara and M. Tanaka, J. Phys. Chem. B, 2017, 121, 1396–1404 CrossRef CAS.

Oral hygiene practices include toothbrushing and the use of other aids for cleaning teeth. Toothbrushing is widely practiced across the UK. In a 2009 national survey of adults [footnote 1], more women reported cleaning their teeth at least twice a day than men (82% compared with 67%). Three quarters (76%) of dentate adults reported using toothpaste with 1,350 to 1,500 parts per million level of fluoride and a further 18 per cent used a brand with a medium (1,000 to 1,350 parts per million) fluoride level. Most dentate adults (58%) used additional products as well as a standard toothpaste and brush, the most common of which were mouthwash (31%), powered toothbrushes (26%) and dental floss (21%). Women and middle-aged adults were more likely to use additional products than men, younger and very old adults (85 years and over). H. Wang, Z. Chen, L. Xin, J. Cui, S. Zhao and Y. Yan, J. Polym. Sci., Part A: Polym. Chem., 2015, 53, 2175–2185 CrossRef CAS.

Acid Brush

C. W. Yang, K. Miyazawa, T. Fukuma, K. Miyata and I. S. Hwang, Phys. Chem. Chem. Phys., 2018, 20, 23522–23527 RSC. J. Rühe, M. Ballauff, M. Biesalski, P. Dziezok, F. Gröhn, D. Johannsmann, N. Houbenov, N. Hugenberg, R. Konradi, S. Minko, M. Motornov, R. R. Netz, M. Schmidt, C. Seidel, M. Stamm, T. Stephan, D. Usov and H. Zhang, Adv. Polym. Sci., 2004, 165, 79–150 CrossRef. X. Xu, D. Mastropietro, M. Ruths, M. Tirrell and J. Yu, Langmuir, 2019, 35, 15564–15572 CrossRef CAS. C. Monzel, M. Veschgini, J. Madsen, A. L. Lewis, S. P. Armes and M. Tanaka, Langmuir, 2015, 31, 8689–8696 CrossRef CAS PubMed.

S. M. R. Akrami, H. Nakayachi, T. Watanabe-Nakayama, H. Asakawa and T. Fukuma, Nanotechnology, 2014, 25, 455701 CrossRef CAS PubMed. Fig. S5 † shows the overlayed force curves extracted from Fig. 4g–i. Similar to the corresponding Δ f curves ( Fig. 4g), the force curves in NaCl buffer overlap with one another, showing a slow increase to F = 3.5 nN at the interface with the onset of F increase at Δ h = 4 nm (Fig. S5a †). This is reasonable because the interface between hydrated polyelectrolyte brushes and the electrolyte is diffusive. 52,53 In the presence of an additional 1 mM CaCl 2, the onset of F increase was observed at a shallower position (Δ h = 2 nm), and F increased to F = 2 nN at the interface (Fig. S5b †). A minor deviation in the force curves indicated that the pAA-Cys5 brushes were uniformly compacted and therefore stiffened following the binding of Ca 2+ ions. Interestingly, the force curves in the presence of Cd 2+ ions showed a much more pronounced deviation (Fig. S5c †). Both the onset of F increase and the F value at Δ h = 0 nm exhibited wide distributions, implying that pAA-Cys5 brushes formed stiff domains on the surface of the phospholipid monolayer. The formation of collapsed domains in the presence of Cd 2+ ions suggested that the compaction-induced dehydration of pAA-Cys5 brushes altered the affinity of the solvent (water) to monomers. Further investigations, including in situ observations of changes in the viscoelasticity of pAA-Cys5 using 3D-SFM or other techniques ( e.g., QCM-D) would provide further insights into the ion-specific, dynamic modulation of polyelectrolyte brushes. Conclusions In this study, we investigated the modulation of topography and mechanical properties of supported lipid monolayers incorporating lipids functionalized with linear poly(acrylic acid) chains with cysteine side chains (DOPE-pAA-Cys5) induced by different metal ions. We found that the topographical profile of pAA-Cys5 brushes obtained by 2D-FM-AFM in the electrolyte containing no divalent cation (100 mM NaCl, 10 mM Tris–HCl, pH = 7.4) was very homogeneous, whose RMS 0 = 0.23 nm ( Fig. 3a). In fact, autocorrelation analysis of Δ h showed no clear feature ( Fig. 3d). The mechanical landscape, characterized by the 3D Δ f map ( Fig. 4a) and its xz cross-section ( Fig. 4d), was also highly uniform, suggesting that the hydrated pAA-Cys5 brushes are stretched into the bulk electrolyte. The slow increase in the Δ f–Δ z curves ( Fig. 4g) and a very low RMS(Δ f) = 0.24 kHz at Δ z = 0 nm ( Fig. 4j) implied a smooth transition from the polymer to the bulk electrolyte. H. Asakawa, S. Yoshioka, K.-i. Nishimura and T. Fukuma, ACS Nano, 2012, 6, 9013–9020 CrossRef CAS PubMed. The risk of dental caries (Chapter 4) and periodontal diseases (Chapter 5) can both be reduced by the practice of regular careful oral hygiene involving toothbrushing with fluoride toothpaste. The particular benefit in preventing dental caries, relates to the fluoride in toothpaste (Chapter 9). Good oral hygiene reduces the risk of periodontal diseases; however, periodontal health also requires effective interproximal plaque removal. Oral hygiene advice for the population in general, and specific advice for those at higher risk, are presented below for each oral condition. Dental cariesT. Fukuma, M. Kimura, K. Kobayashi, K. Matsushige and H. Yamada, Rev. Sci. Instrum., 2005, 76, 053704 CrossRef. Delivering Better Oral Health has been developed with the support of the 4 UK Chief Dental Officers. The addition of 1 mM CaCl 2 caused a distinct change in both topographical and mechanical properties of the brush/electrolyte interface. In the presence of Ca 2+ ions, pAA-Cys5 brushes became smoother, which could be characterized by the very small roughness, RMS Ca = 0.15 nm ( Fig. 3b) with no characteristic feature ( Fig. 3e). The 3D Δ f map and its xz cross-section ( Fig. 4b and e) were smoother, and the increase in Δ f was much sharper ( Fig. 4h) than the corresponding values obtained in the absence of Ca 2+ ions, RMS(Δ f) = 0.37 kHz at Δ z = 0 nm ( Fig. 4j), indicating that pAA-Cys5 brushes are uniformly compacted by the presence of Ca 2+ ions. The most remarkable difference was observed when 1 mM CdCl 2 was added to the electrolyte. The surface topography became very rough (RMS Cd = 1.47 nm, Fig. 3c), displaying hemi-ellipsoidal features. The autocorrelation analysis suggested that these protrusions had a similar size and assembled randomly ( Fig. 3f). Accordingly, the 3D Δ f map became highly heterogeneous ( Fig. 4c), and the xz cross-section ( Fig. 4f) clearly indicates the coexistence of stiff protrusions and defects. The heterogeneity of the mechanical landscape was clearly visible from a broad distribution of the Δ f–Δ z curves, resulting in RMS(Δ f) = 1.90 kHz at Δ z = 0 nm ( Fig. 4j). These data suggest that pAA-Cys5 brushes “collapsed” in the presence of Cd 2+ ions, where water might not be a good solvent for pAA-Cys5. H. Songen, B. Reischl, K. Miyata, R. Bechstein, P. Raiteri, A. L. Rohl, J. D. Gale, T. Fukuma and A. Kuhnle, Phys. Rev. Lett., 2018, 120, 116101 CrossRef PubMed. Fig. 5 Correlations between the surface topography and mechanical heterogeneity of pAA-Cys5 polymer brushes in 100 mM NaCl + 1 mM CdCl 2 based on 3D-SFM mapping. (a) Surface topography. A white square and a white diamond indicate the positions of representative topographically high points (Δ h = 4.2 and 3.4 nm, respectively), and a grey circle and a grey triangle indicate the positions of representative topographically low points (Δ h = 2.6 and 1.3 nm, respectively). (b) 2D map of Δ f at the Δ z = 0 plane. Scale bars: 20 nm. (c and d) Force curves measured at (c) the protrusions and (d) the smooth regions; baselines are offset for clarity. (e) A schematic presentation of pAA-Cys5 brushes on a phospholipid monolayer and lateral stiffness distribution in the presence of Cd 2+ ions.