Enhancing Intraoral Fluoride Retention in Older Adults: A Randomized Crossover Study.

INTRODUCTION: Previous studies have shown that a calcium prerinse can increase intraoral fluoride retention from a fluoride rinse. To explore the potential of this approach to control root caries, we assessed intraoral fluoride bioavailability after a calcium prerinse in older adults with normal to low salivary flow rates. METHODS: In a 2-period crossover trial (NCT04239872), 20 participants (65-80 y old), with low or normal salivary flow rate, rinsed for 1 min with a 0.05% NaF mouth rinse (226 ppm F, F only) or with this rinse immediately after a 1-min rinse with 150 mM calcium lactate (Ca→F). Dental biofilm and saliva samples were collected before and up to 2 h after the rinse(s). Fluoride concentrations in saliva (whole and clarified) and dental biofilm (fluid and solid phases) were blindly determined. Data were statistically analyzed by a mixed-effects model for the effect of treatment, time, and their interaction (α = 5%). RESULTS: The Ca→F group resulted in significantly higher fluoride concentrations in all variables analyzed, for almost all of the collection time points. The effect was greater in the biofilm solids and whole saliva (compatible with the formation of calcium fluoride deposits) and still significant (P < 0.001) after 2 h in the biofilm fluid and clarified saliva, suggesting that fluoride stored in insoluble particles was released, increasing free fluoride. CONCLUSION: The use of a calcium prerinse before a fluoride rinse was able to prolong intraoral fluoride bioavailability in older adults. KNOWLEDGE TRANSFER STATEMENT: A calcium prerinse increased intraoral fluoride bioavailability in older individuals. This approach could be used to improve root caries control without the need to increase the fluoride concentration in dental products.

Extreme ultraviolet interferometry of warm dense matter in laser plasmas.

We demonstrate that interferometric probing with extreme ultraviolet (EUV) laser light enables determination of the degree of ionization of the "warm dense matter" produced between the critical and ablation surfaces of laser plasmas. Interferometry has been utilized to measure both transmission and phase information for an EUV laser beam at the photon energy of 58.5 eV, probing longitudinally through laser-irradiated plastic (parylene-N) targets (thickness 350 nm) irradiated by a 300 ps duration pulse of wavelength 438 nm and peak irradiance 10(12) W cm(-2). The transmission of the EUV probe beam provides a measure of the rate of target ablation, as ablated plasma becomes close to transparent when the photon energy is less than the ionization energy of the predominant ion species. We show that refractive indices η below the solid parylene N (η(solid) = 0.946) and expected plasma values are produced in the warm dense plasma created by laser irradiation due to bound-free absorption in C(+).

Hugoniot data of plastic foams obtained from laser-driven shocks.

In this paper we present Hugoniot data for plastic foams obtained with laser-driven shocks. Relative equation-of-state data for foams were obtained using Al as a reference material. The diagnostics consisted in the detection of shock breakout from double layer Al/foam targets. The foams [poly(4-methyl-1-pentene) with density 130 > rho > 60 mg/cm3] were produced at the Institute of Laser Engineering of Osaka University. The experiment was performed using the Prague PALS iodine laser working at 0.44 microm wavelength and irradiances up to a few 10(14) W/cm2. Pressures as high as 3.6 Mbar (previously unreached for such low-density materials) where generated in the foams. Samples with four different values of initial density were used, in order to explore a wider region of the phase diagram. Shock acceleration when the shock crosses the Al/foam interface was also measured.

Cardiac rate and rhythm in panic patients.

This study assessed cardiac rate and rhythm by ambulatory monitoring in 23 patients with panic disorder or agoraphobia with panic attacks. The patients had a higher than normal mean daily density of ventricular premature complexes (VPCs), but complex ventricular arrhythmias were uncommon. Heart rate was greater during panic intervals than during asymptomatic periods. The prevalence of arrhythmias within symptomatic intervals was similar during panic, partial panic, and anxiety and was significantly higher than during asymptomatic intervals. However, most panic episodes had no arrhythmias, and arrhythmias during panic intervals were simple VPCs.

Single-shot soft x-ray laser-induced ablative microstructuring of organic polymer with demagnifying projection.

We report on a single-shot micropatterning of an organic polymer achieved by ablation with demagnifying projection using a Ne-like Zn 21.2 nm soft x-ray laser. A nickel mesh with a period of 100 microm was approximately 10x demagnified and imprinted on poly(methyl methacrylate) via direct ablation. The quality of the ablated microstructure was found to be mainly dependent on the quality of the projected mask. This first demonstration (to our knowledge) of single-shot projection, single-step lithography illustrates the potential of soft x-ray lasers for the direct patterning of materials with a resolution scalable down to submicrometer domain.

Laser-ablation rates measured using x-ray laser transmission.

The rate of laser ablation at irradiances of approximately 2 x 10{14} W cm{-2} of solid iron has been measured using the transmission of a neonlike zinc x-ray laser at 21.2 nm through thin iron targets. Ablated iron becomes transparent to the x-ray laser flux, enabling the thickness of unablated material and hence the rate of ablation to be measured from time resolved x-ray laser transmission.