Isolating the Effect of Off-Road Glance Duration on Driving Performance: An Exemplar Study Comparing HDD and HUD in Different Driving Scenarios.

OBJECTIVE: We controlled participants' glance behavior while using head-down displays (HDDs) and head-up displays (HUDs) to isolate driving behavioral changes due to use of different display types across different driving environments. BACKGROUND: Recently, HUD technology has been incorporated into vehicles, allowing drivers to, in theory, gather display information without moving their eyes away from the road. Previous studies comparing the impact of HUDs with traditional displays on human performance show differences in both drivers' visual attention and driving performance. Yet no studies have isolated glance from driving behaviors, which limits our ability to understand the cause of these differences and resulting impact on display design. METHOD: We developed a novel method to control visual attention in a driving simulator. Twenty experienced drivers sustained visual attention to in-vehicle HDDs and HUDs while driving in both a simple straight and empty roadway environment and a more realistic driving environment that included traffic and turns. RESULTS: In the realistic environment, but not the simpler environment, we found evidence of differing driving behaviors between display conditions, even though participants' glance behavior was similar. CONCLUSION: Thus, the assumption that visual attention can be evaluated in the same way for different types of vehicle displays may be inaccurate. Differences between driving environments bring the validity of testing HUDs using simplistic driving environments into question. APPLICATION: As we move toward the integration of HUD user interfaces into vehicles, it is important that we develop new, sensitive assessment methods to ensure HUD interfaces are indeed safe for driving.

U can't touch this! Face touching behaviour whilst driving: implications for health, hygiene and human factors.

Analysis of thirty-one hours of video-data documenting 36 experienced drivers highlighted the prevalence of face-touching, with 819 contacts identified (mean frequency: 26.4 face touches/hour (FT/h); mean duration: 3.9-seconds). Fewer face-touches occurred in high primary workload conditions (where additional physical/cognitive demands were placed on drivers), compared to low workload (4.4 and 26.1 FT/h, respectively). In 42.5% of touches (or 11.2 FT/h), mucous membrane contact was made, with fingertips (33.1%) and thumbs (35.6%) most commonly employed. Individual behaviours differed (ranging from 5.1 to 90.7 FT/h), but there were no significant differences identified between genders, age-groups or hand used. Results are of relevance from an epidemiological/hygiene perspective within the context of the COVID-19 pandemic (and can therefore inform the design of practical solutions and encourage behavioural change to reduce the risk of self-inoculation while driving), but they also help to elucidate how habitual human behaviours are imbricated with the routine accomplishment of tasks.

Practitioner summary: The study highlights the propensity of face touching whilst driving through the analysis of on-road video datasets. Results have implications for the design of technological interventions (such as touchless interfaces and driver monitoring systems) and can inform awareness campaigns to reduce the risk of self-inoculation and infection transmission while driving.

Interdental and subgingival microbiota may affect the tongue microbial ecology and oral malodour in health, gingivitis and periodontitis.

BACKGROUND AND OBJECTIVE: Oral malodour is often observed in gingivitis and chronic periodontitis patients, and the tongue microbiota is thought to play a major role in malodorous gas production, including volatile sulphur compounds (VSCs) such as hydrogen sulphide (H2 S) and methanethiol (CH3 SH). This study aimed to examine the link between the presence of VSCs in mouth air (as a marker of oral malodour) and the oral bacterial ecology in the tongue and periodontal niches of healthy, gingivitis and periodontitis patients. METHODS: Participants were clinically assessed using plaque index, bleeding on probing (BOP) and periodontal probing depths, and VSC concentrations in their oral cavity measured using a portable gas chromatograph. Tongue scrapings, subgingival and interdental plaque were collected from healthy individuals (n = 22), and those with gingivitis (n = 14) or chronic periodontitis (n = 15). The bacterial 16S rRNA gene region V3-V4 in these samples was sequenced, and the sequences were analysed using the minimum entropy decomposition pipeline. RESULTS: Elevated VSC concentrations and CH3 SH:H2 S were observed in periodontitis compared with health. Significant ecological differences were observed in the tongue microbiota of healthy subjects with high plaque scores compared to low plaque scores, suggesting a possible connection between the microbiota of the tongue and the periodontium and that key dysbiotic changes may be initiated in the clinically healthy individuals who have higher dental plaque accumulation. Greater subgingival bacterial diversity was positively associated with H2 S in mouth air. Periodontopathic bacteria known to be prolific VSC producers increased in abundance on the tongue associated with increased bleeding on probing (BOP) and total percentage of periodontal pockets >6 mm, supporting the suggestion that the tongue may become a reservoir for periodontopathogens. CONCLUSION: This study highlights the importance of the periodontal microbiota in malodour and has detected dysbiotic changes in the tongue microbiota in periodontitis.

Gait Parameters Measured from Wearable Sensors Reliably Detect Freezing of Gait in a Stepping in Place Task.

Freezing of gait (FOG), a debilitating symptom of Parkinson's disease (PD), can be safely studied using the stepping in place (SIP) task. However, clinical, visual identification of FOG during SIP is subjective and time consuming, and automatic FOG detection during SIP currently requires measuring the center of pressure on dual force plates. This study examines whether FOG elicited during SIP in 10 individuals with PD could be reliably detected using kinematic data measured from wearable inertial measurement unit sensors (IMUs). A general, logistic regression model (area under the curve = 0.81) determined that three gait parameters together were overall the most robust predictors of FOG during SIP: arrhythmicity, swing time coefficient of variation, and swing angular range. Participant-specific models revealed varying sets of gait parameters that best predicted FOG for each participant, highlighting variable FOG behaviors, and demonstrated equal or better performance for 6 out of the 10 participants, suggesting the opportunity for model personalization. The results of this study demonstrated that gait parameters measured from wearable IMUs reliably detected FOG during SIP, and the general and participant-specific gait parameters allude to variable FOG behaviors that could inform more personalized approaches for treatment of FOG and gait impairment in PD.

In situ efficacy of an experimental toothpaste on enamel rehardening and prevention of demineralisation: a randomised, controlled trial.

BACKGROUND: A novel sodium fluoride toothpaste containing lactate ion and polyvinylmethylether-maleic anhydride has been developed to promote enamel remineralisation and resistance to demineralisation. In this in situ study, we compared this toothpaste ('Test') with a stannous fluoride-zinc citrate (SnF2-Zn) toothpaste ('Reference') (both 1100-1150 ppm fluoride) and a fluoride-free toothpaste ('Placebo') using an enamel dental erosion-rehardening model. METHODS: In each phase of this randomised, investigator-blind, crossover study, participants wore palatal appliances holding bovine enamel specimens with erosive lesions. They brushed their natural teeth with either the Test, Reference or Placebo toothpastes, then swished the resultant slurry. Specimens were removed at 2 h and 4 h post-brushing and exposed to an in vitro acid challenge. Surface microhardness was measured at each stage; enamel fluoride uptake was measured after in situ rehardening. Surface microhardness recovery, relative erosion resistance, enamel fluoride uptake and acid resistance ratio were calculated at both timepoints. RESULTS: Sixty two randomised participants completed the study. Test toothpaste treatment yielded significantly greater surface microhardness recovery, relative erosion resistance and enamel fluoride uptake values than either Reference or Placebo toothpastes after 2 and 4 h. The acid resistance ratio value for Test toothpaste was significantly greater than either of the other treatments after 2 h; after 4 h, it was significantly greater versus Placebo only. No treatment-related adverse events were reported. CONCLUSIONS: In this in situ model, the novel-formulation sodium fluoride toothpaste enhanced enamel rehardening and overall protection against demineralisation compared with a fluoride-free toothpaste and a marketed SnF2-Zn toothpaste. TRIAL REGISTRATION: ClinicalTrials.gov; NCT03296072; registered September 28, 2017.

Impact of toothpaste on oral health-related quality of life in people with dentine hypersensitivity.

BACKGROUND: Dentine hypersensitivity can impact functional status and everyday activities such as eating and talking. This study aimed to assess changes in oral health-related quality of life measures in individuals with dentine hypersensitivity following long-term use (24 weeks) of a commercially available toothpaste marketed for dentine hypersensitivity relief. METHODS: This study was conducted across two sites and enrolled 75 adults with ≥2 non-adjacent sensitive teeth. Participants were assigned to twice-daily brushing with toothpaste containing 0.454% w/w stannous fluoride (1100 ppm fluoride). Every 4 weeks, participant-reported outcomes were assessed using the Dentine Hypersensitivity Experience Questionnaire (DHEQ), a condition specific oral health-related quality of life scale that has five domains and includes questions on social and emotional impact, restrictions, adaptations and effect on life overall. Responses to a clinically applied evaporative (air) stimulus were assessed using the examiner-observed Schiff sensitivity scale and Labelled Magnitude Scales (LMS), which included dentine hypersensitivity-specific descriptors of intensity, duration, tolerability and descriptive qualities of the participant's response. RESULTS: Participant-reported outcomes demonstrated reduction of the impact of dentine hypersensitivity over time on health-related quality of life, as measured by the DHEQ. This reached statistical significance from Week 8 onwards (p < 0.0001 versus baseline) for the Total DHEQ score, with scores continually decreasing at each timepoint. Most domain scores followed a similar pattern. Statistically significant reductions were also detected for the examiner-observed Schiff Sensitivity Scale scores at all timepoints (including at 4 weeks) (p < 0.05), which were mirrored by LMS responses. The toothpaste was generally well-tolerated. CONCLUSIONS: These results show that long-term use of a sensitivity toothpaste containing 0.454% w/w stannous fluoride has a beneficial, ongoing, impact on the oral health-related quality of life of people with dentine hypersensitivity. TRIAL REGISTRATION: This study was registered at Clinicaltrials.gov ( https://clinicaltrials.gov/ct2/show/NCT02752958 ) on April 27, 2016.

Randomized Controlled Clinical Study to Determine the Oral and Dermal Tolerability of an Experimental Denture Wipe.

PURPOSE: To evaluate oral and dermal tolerance following use and user acceptability of an experimental denture-cleansing wipe. An exploratory objective was to develop a method to assess denture wipe effectiveness in removing debris from denture surfaces. MATERIALS AND METHODS: This was a single-center, randomized, controlled, parallel-group, examiner-blind study in participants with ≥1 full/partial denture. Participants were randomized to clean their dentures with the denture wipe (n = 76) or water (n = 76) up to 4 times per day for 14 days. Tolerability was assessed by treatment-emergent adverse events (TEAEs), oral soft tissue examination, and lead hand dermatological assessment. Acceptability was assessed by questionnaire. The feasibility of a methodology to assess the efficacy of the wipe at removing food particles was also evaluated through determination of the mass of chewed peanut particles that the wipe removed after a single use (n = 31). RESULTS: The proportion of participants experiencing oral TEAEs by day 14 was 0.039% with the denture wipe (lip injury [n = 1], mouth injury [n = 2]) and 0.013% with the water rinse (coated tongue [n = 1]). There were no dermal TEAEs and no TEAE-related study withdrawals. Skin irritation scores with the denture wipe remained unchanged from baseline. Comparing before vs. after cleaning with the denture wipe, a higher proportion of participants rated their dentures as feeling extremely/very fresh (28.9% pre-/85.5% post-cleaning), feeling extremely/very clean (34.2%/86.8%) and looking extremely/very clean (43.5%/85.5%). More denture-wipe group participants than water-rinse group participants were extremely/very satisfied with the amount of debris removed from their dentures (88.1% vs 72.4%). The methodology used to assess the weight of peanut particles captured from the wipes/dentures appeared to be a feasible investigation technique. CONCLUSIONS: The denture wipe was generally well-tolerated and had good user acceptability. The methodology for assessing the mass of peanut particles removed by denture wipes was successful.

Randomized exploratory study to measure ion release from calcium sodium phosphosilicate-containing dentifrice.

This exploratory study investigated salivary concentrations of silicon, calcium, sodium, and phosphorous over a 60-min time period following the use of a calcium sodium phosphosilicate (CSPS)-containing dentifrice. Participants brushed with a dentifrice containing 5% (w/w) or 0% (w/w) CSPS or swilled with a slurry containing 5% (w/w) CSPS/glycerol. Saliva samples were collected before, and 2, 5, 15, and 60 min after, product use and were analysed using inductively coupled plasma optical emission spectroscopy. Intra-oral pH measurements were also taken. Primary analysis was of centrifuged saliva supernatant containing only dissolved material. At most time points, the CSPS-containing dentifrice and slurry generated significantly more salivary silicon than the dentifrice containing 0% CSPS. At 2-15 min after brushing there was significantly more salivary calcium after use of the CSPS-containing dentifrice and slurry, compared with the 0% CSPS dentifrice; a significant reduction, from baseline, in salivary calcium after use of dentifrice containing 0% CSPS; and an increase in salivary sodium after use of dentifrices containing either 5% or 0% CSPS, but no differences between them. Salivary phosphorous concentration decreased significantly with all treatments 2-5 min after use. There were no significant between-treatment differences in intra-oral pH. Products were generally well tolerated. This study establishes that it is possible to measure changes in salivary ionic composition derived through oral retention of CSPS, delivered via a dentifrice.

Effects of a sodium fluoride- and phytate-containing dentifrice on remineralisation of enamel erosive lesions-an in situ randomised clinical study.

OBJECTIVE: The objective of this work was to evaluate effects of a dentifrice containing sodium fluoride (1150 ppm F) and the organic polyphosphate phytate (0.85% w/w of the hexa-sodium salt) on in situ remineralisation of early enamel erosive lesions and resistance to subsequent demineralisation. MATERIALS AND METHODS: Subjects (n = 62) wore palatal appliances holding eight bovine enamel specimens with pre-formed erosive lesions. They brushed their natural teeth with the phytate test dentifrice (TD); a positive control dentifrice (PC, 1150 ppm fluoride as NaF); a reference dentifrice (RD, disodium pyrophosphate + 1100 ppm fluoride as NaF) or a negative control dentifrice (NC, fluoride-free) in a randomised, double-blind, crossover design. Specimens were removed at 2, 4 and 8 h post-brushing and exposed to an ex vivo acid challenge. Surface microhardness (Knoop) was measured at each stage. The primary efficacy variable was relative erosion resistance (RER); other variables included the surface microhardness recovery (SMHR), acid resistance ratio (ARR) and enamel fluoride uptake (EFU). RESULTS: After 4 h, the results for RER, ARR and EFU were in the order PC > TD = RD > NC with PC > TD = RD = NC for SMHR. Results at 2 and 8 h were generally consistent with the 4 h data. Mineralisation progressed over time. Dentifrices were generally well-tolerated. CONCLUSIONS: In this in situ model, addition of phytate or pyrophosphate to a fluoride dentifrice inhibited the remineralising effect of fluoride. Both formulations still delivered fluoride to the enamel and inhibited demineralisation, albeit to a lesser extent than a polyphosphate-free dentifrice. CLINICAL RELEVANCE: Addition of phytate or pyrophosphate to a fluoride dentifrice may reduce its net anti-erosive properties.

A randomized clinical trial to evaluate the stain removal efficacy of a sodium phytate dentifrice formulation.

OBJECTIVES: Phytate is an organic, cyclic polyphosphate analogous to linear condensed polyphosphates used as stain removal agents. This study investigated stain removal efficacy of an experimental sodium phytate-containing dentifrice compared to a reference dentifrice. METHODS: An experimental, moderate abrasivity (relative dentine abrasivity [RDA] âˆ¼130) antisensitivity fluoride dentifrice containing sodium phytate (0.85% w/w as the hexasodium salt) (n = 111) was compared to a reference, marketed, low-abrasivity (RDA âˆ¼ 43), anti-sensitivity fluoride dentifrice (n = 113), both containing 1150 ppm fluoride as sodium fluoride. Primary efficacy variables were between-treatment differences in extrinsic dental stain of anterior teeth after 6 and 12 weeks' twice-daily use, using Lobene stain index (MacPherson modification, MLSI) mean area (A) and intensity (I) scores. Comparisons included whole-tooth and hard-to-reach areas (gingival, interproximal, body of lingual). RESULTS: At both 6- and 12-week timepoints, MLSI (A × I) scores for total area and hard-to-reach areas for the experimental dentifrice were statistically significantly lower than baseline (P < .0001 for all). This was demonstrated for the reference dentifrice at 6 weeks only, for total, interproximal (P < .0001 for both), and body of lingual (P = .0395) scores. Compared with the reference, the experimental dentifrice had statistically significantly lower MLSI scores at both 6 and 12 weeks for all outcome variables including both total MLSI (A × I) and hard-to reach areas (P < .0001 in all cases). Products were generally well-tolerated. CONCLUSIONS: Differences between treatments were considered clinically differentiable. Sodium phytate may therefore be a suitable additive ingredient to improve tooth stain control performance within an otherwise conventional dentifrice formulation. CLINICAL SIGNIFICANCE: Following 6 and 12 weeks brushing, clinically differentiable differences were shown in stain index scores with an experimental dentifrice containing sodium phytate compared to a reference dentifrice without sodium phytate. Sodium phytate may therefore be a suitable additive ingredient to improve tooth stain control performance within an otherwise conventional dentifrice formulation.

Driver-passenger collaboration as a basis for human-machine interface design for vehicle navigation systems.

Human Factors concerns exist with vehicle navigation systems, particularly relating to the effects of current Human-Machine Interfaces (HMIs) on driver disengagement from the environment. A road study was conducted aiming to provide initial input for the development of intelligent HMIs for in-vehicle systems, using the traditional collaborative navigation relationship between the driver and passenger to inform future design. Sixteen drivers navigated a predefined route in the city of Coventry, UK with the assistance of an existing vehicle navigation system (SatNav), whereas a further 16 followed the navigational prompts of a passenger who had been trained along the same route. Results found that there were no significant differences in the number of navigational errors made on route for the two different methods. However, drivers utilising a collaborative navigation approach had significantly better landmark and route knowledge than their SatNav counterparts. Analysis of individual collaborative transcripts revealed the large individual differences in descriptor use by passengers and reference to environmental landmarks, illustrating the potential for the replacement of distance descriptors in vehicle navigation systems. Results are discussed in the context of future HMIs modelled on a collaborative navigation relationship. Practitioner Summary: Current navigation systems have been associated with driver environmental disengagement, this study uses an on-road approach to look at how the driver-passenger collaborative relationship and dialogue can inform future navigation HMI design. Drivers navigating with passenger assistance demonstrated enhanced landmark and route knowledge over drivers navigating with a SatNav.

Structural and compositional changes in the salivary pellicle induced upon exposure to SDS and STP.

Sodium dodecyl sulphate (SDS) and sodium tripolyphosphate (STP) act to remove stained pellicle from dentition and loosen deposits on tooth surfaces that may become cariogenic over time. This study investigated how SDS and STP impact the salivary pellicle adsorbed onto hydroxyapatite and silica sensors using a dual polarisation interferometer and a quartz-crystal microbalance with dissipation. After the pellicle was exposed to SDS and STP the remaining pellicle, although weaker, due to the loss of material, became less dense but with a higher elastic component; suggesting that the viscous component of the pellicle was being removed. This would imply a structural transformation from a soft but dense structured pellicle, to a more diffuse pellicle. In addition, the majority of proteins displaced by both SDS and STP were identified as being acidic in nature; implying that the negatively charged groups of SDS and STP may be responsible for the displacement of the pellicle proteins observed.

In vitro growth characteristics and volatile sulfur compound production of Solobacterium moorei.

Solobacterium moorei has recently been implicated as a causative agent of halitosis. In vitro experiments to evaluate the role of S. moorei in halitosis have, however, been complicated by a paucity of information on the ideal conditions for culturing this organism. This work aimed to optimize a liquid culture medium for S. moorei, and to determine the growth-curve of the organism. Further, the ability of S. moorei to generate volatile sulfur compounds was investigated and compared quantitatively to other oral anaerobes by an optimized head-space gas chromatography method. Serum-supplementation of standard liquid growth media gave greater growth of S. moorei than non-supplemented broths, with the best medium found to be serum-supplemented tryptone soya broth. S. moorei was able to metabolize cysteine directly to hydrogen sulfide, but was unable to produce methanethiol from methionine. S. moorei produced 2-3 times more hydrogen sulfide (normalized for colony forming units) than Porphyromonas gingivalis and Veillonella dispar, but considerably less than Fusobacterium nucleatum. The study has identified reliable growth conditions for culture of S. moorei, which were employed to show that S. moorei has the requisite biochemistry consistent with a potential role in halitosis.

The effect of an experimental anhydrous stannous fluoride dentifrice on the acid resistance of dentin smear layers.

PURPOSE: To compare the relative performance, in an in vitro assay, of a standard dentifrice (Colgate Cavity Protection) with an experimental anhydrous 0.454% w/w stannous fluoride dentifrice at protecting the dentin smear layer against dietary acids. METHODS: Artificial smear layers were created on bovine dentin, contacted with slurries of the dentifrices, then exposed to a dietary acid (Coca Cola) for periods up to 10 minutes. Both the stability of the smear layer and tubule occlusion were assessed qualitatively by scanning electron microscopy and confocal laser scanning microscopy. RESULTS: Smear layers treated with the standard dentifrice were removed after 2 minutes of exposure to cola with the smear plugs progressively eroded by longer acid challenges, leaving patent tubules. Treatment with the experimental stannous fluoride dentifrice provided extensive protection of the smear layer against cola for up to 10 minutes, with very few tubules unoccluded.

In vitro studies investigating the dentin tubule-occlusion properties of an experimental anhydrous stannous fluoride dentifrice.

PURPOSE: To evaluate in vitro the ability for an experimental anhydrous 0.454% w/w stannous fluoride dentifrice to occlude dentin tubules. METHODS: Scanning electron microscopy (SEM) was used to assess tubule occlusion and the resistance of the occlusion to dietary acid in a 4-day model, where bovine dentin was treated with product twice daily with acid challenges administered on Days 3 and 4. The reduction in hydraulic conductance of the dentin following treatment was also measured. RESULTS: The experimental stannous fluoride dentifrice was effective at reducing the hydraulic conductance of dentin by occluding tubules. The occlusion was resistant to challenge with grapefruit juice.

Examining pedestrians' trust in automated vehicles based on attributes of trust: A qualitative study.

Pedestrians' trust in automated vehicles (AVs) needs to be analyzed and deconstructed to update it from its current broad concept into several lower-level attributes for assessment and measurement. In this study, we have employed virtual reality (VR) and scenario-based interviews to examine the trust of pedestrians toward AVs, based on the attributes of trust and trustworthiness. A hybrid approach of inductive and deductive thematic analysis of the responses of 36 participants was undertaken. Eight such attributes emerged from the analysis, including statistical reliability and dependability, competence, predictability, familiarity, authority/subversion, liberty/oppression, care/harm, and sanctity/degradation. The first four are objective attributes concerning automation trustworthiness and human trust in automation, while the remaining four are subjective attributes, analogous to properties of human morality. The findings of this study provide an empirical grounding for trust theories. Specifically, we have highlighted the importance of subjective qualities in constituting pedestrian-AV trust, including "automation morality" and "care/harm".

A randomized clinical study to assess the performance of a marketed denture adhesive in a model of food infiltration in healthy, edentulous adults.

OBJECTIVES: An optimized food infiltration methodology was utilized to assess the objective and subjective efficacy of a marketed denture adhesive regarding denture dislodgment and infiltration and perception of food particles under maxillary and mandibular dentures. A pilot study helped optimize methodologies before the efficacy study. MATERIALS AND METHODS: Participants were healthy adults (n =48 for both studies) with fair- to well-fitting and well-made full maxillary and mandibular dentures. In the pilot, groups were a denture adhesive applied in a conventional dabbed-on pattern, a denture adhesive applied in continuous strips, or no adhesive. In the efficacy study, groups were the Test denture adhesive (continuous strips pattern application) or no adhesive, employed in a crossover design. Food infiltration was investigated through measurement of peanut particle mass retrieved from under each denture (30-32 g chewed). No formal statistical testing was performed in the pilot. Statistical analysis in the efficacy study was performed using analysis of variance. Primary efficacy evaluation was combined peanut particle mass from both dentures. Secondary efficacy evaluations included peanut particle mass under separate dentures, participant-reported denture dislodgements, and awareness/rates of how bothersome peanut particles under dentures were. RESULTS: In the pilot, the median peanut particle mass was lower with either pattern application compared with no adhesive. In the efficacy study, peanut particle mass under combined dentures was lower with than without adhesive (geometric mean [product of values]: 5.56 vs. 29.13 mg) with a between-group geometric mean ratio (adhesive over no adhesive) of 0.19 (95% confidence interval: 0.12, 0.30) favoring the Test adhesive (p < .0001). Similar Test adhesive beneficial outcomes in both studies included significantly fewer denture dislodgements and awareness and how bothersome peanut particles under dentures were. Treatments were generally well-tolerated. CONCLUSIONS: These findings, including reduced peanut particle infiltration, fewer denture dislodgments, and lower ratings of bothersomeness, corroborate those studies investigating the benefits of denture adhesive in preventing food infiltration.

A Perceptual Color-Matching Method for Examining Color Blending in Augmented Reality Head-Up Display Graphics.

Augmented reality (AR) offers new ways to visualize information on-the-go. As noted in related work, AR graphics presented via optical see-through AR displays are particularly prone to color blending, whereby intended graphic colors may be perceptually altered by real-world backgrounds, ultimately degrading usability. This work adds to this body of knowledge by presenting a methodology for assessing AR interface color robustness, as quantitatively measured via shifts in the CIE color space, and qualitatively assessed in terms of users' perceived color name. We conducted a human factors study where twelve participants examined eight AR colors atop three real-world backgrounds as viewed through an in-vehicle AR head-up display (HUD); a type of optical see-through display used to project driving-related information atop the forward-looking road scene. Participants completed visual search tasks, matched the perceived AR HUD color against the WCS color palette, and verbally named the perceived color. We present analysis that suggests blue, green, and yellow AR colors are relatively robust, while red and brown are not, and discuss the impact of chromaticity shift and dispersion on outdoor AR interface design. While this work presents a case study in transportation, the methodology is applicable to a wide range of AR displays in many application domains and settings.

Dual-fluorophore ratiometric pH nanosensor with tuneable pKa and extended dynamic range.

Ratiometric pH nanosensors with tuneable pK(a) were prepared by entrapping combinations of two pH-sensitive fluorophores (fluorescein isothiocyanate dextran (FITC-D) and Oregon Green(®) dextran (OG-D)) and a reference fluorophore (5-(and-6)-carboxytetramethylrhodamine dextran (TAMRA-D)), in a biocompatible polymer matrix. Dual-fluorophore pH nanosensors permit the measurement of an extended dynamic range, from pH 4.0 to 7.5.

In vitro effects of novel toothpaste actives on components of oral malodour.

OBJECTIVES: To evaluate the efficacy of a novel toothpaste containing zinc ions and o-cymen-5-ol to reduce volatile sulfur compounds (VSCs) in in vitro models and to elucidate the mode of action for any activity observed. METHODS: Three models were employed, a chemical neutralisation model to evaluate the chemical reactivity of toothpaste slurries to VSCs, a biofilm perfusion model to measure activity in an orally-relevant biofilm and a planktonic bacterial model to measure antimicrobial effects. RESULTS: The models showed that zinc ions were able to react chemically with hydrogen sulfide to remove this odorous component of halitotic breath. This activity was confirmed within a complex biofilm model, with over 90% of hydrogen sulfide removed from perfusate gas by a slurry of the test toothpaste. CONCLUSIONS: This work provides a mode of action for the clinically observed reduction in VSCs seen for up to 12 hours post brushing with this novel toothpaste.