Impedance Control of a 2-DOF Spherical 5-Bar Exoskeleton for Physical Human-Robot Interaction During Rehabilitation and Assessment.

This paper presents a novel impedance controller for THINGER (THumb INdividuating Grasp Exercise Robot), a 2-degree-of-freedom (DOF) spherical 5-bar exoskeleton designed to augment FINGER (Finger INdividuating Grasp Exercise Robot). Many rehabilitation and assessment tasks, for which THINGER is designed, are improved by rendering near-zero impedance during physical human-robot interaction (pHRI). To achieve this goal, the presented impedance controller includes several novel features. First, a reference trajectory is omitted, allowing free movements. Second, force-feedback gains are reduced near actuator limits and a saturation function limits the maximum commanded force; both allow more responsive (higher) force-feedback gains within the workspace and mitigate transient oscillations caused by external disturbances. Finally, manipulability-based directional force-feedback gains help improve rendered impedance isotropy. Validation experiments included free exploration of the workspace, following a prescribed circular thumb motion, and intentional exposure to external disturbances. The experimental results show that the presented impedance controller significantly reduces impedance to subject-initiated motion and accurately renders the desired isotropic low-impedance environment.

Sustained oral health improvement and use of toothbrushes and dentifrice by previous users of traditional materials in a rural population in Andhra Pradesh, India.

AIM: To follow-up, one year later, a double-blind, randomised study, which investigated the effect of regular brushing with dentifrices on the oral health of an economically disadvantaged rural population in Andhra Pradesh, India who were primarily users of traditional materials. SUBJECTS: 150 of the original study population. METHOD: Examination to determine whether the improvements in oral health status and oral health behaviour (use of toothbrush and dentifrice), being unsupported, had been sustained since completion of the original study. RESULTS: Data analysis showed sustained, statistically significant improvements in gingival health as measured by gingival bleeding and plaque indices (GBI and PI) comparing users and non-users of toothbrushes and dentifrice in the original study (PI: p = 0.04; GBI: p = 0.03) and sustained use of toothbrushes and dentifrice by 60% of the subjects at follow-up one year later. CONCLUSIONS: This study shows a beneficial effect on oral hygiene indices following the introduction of toothbrushes and dentifrices to a community using traditional oral hygiene materials and sustainability of use of these materials with motivation and support. It may therefore be concluded that it is feasible to achieve significant use of conventional toothbrushes and toothpastes, with consequent major and sustained improvements in plaque control and gingival health in a disadvantaged population hitherto often considered as not amenable to conventional oral hygiene for cultural or economic reasons.

Effect of toothpaste with natural calcium carbonate/perlite on extrinsic tooth stain.

OBJECTIVE: The current study was designed to determine the effect of natural calcium carbonate toothpaste containing Perlite and microgranules (Whitening toothpaste) on extrinsic tooth stain compared to a standard commercial toothpaste formulation with precipitated calcium carbonate (PCC) as abrasive and a commercial toothpaste with dicalcium phosphate dihydrate (DCPD) as abrasive. METHODS: The toothpastes were evaluated in a double blind, three-cell, stratified (tobacco use; baseline tooth stain level), parallel group design study involving 600 subjects with extrinsic tooth stain. Subjects brushed twice daily with their allocated toothpaste for four weeks. Extrinsic tooth stain was measured using the Macpherson modification of the Lobene stain index. RESULTS: ANCOVA showed significant differences between toothpastes (p=0.037). Subsequent multiple comparisons using pairwise t-tests, showed the Whitening toothpaste to be superior to the DCPD toothpaste (p=0.014) and the PCC toothpaste (p=0.067). When a Box-Cox transformation was made to the data (y0.6) to improve normality, these two differences were more accurately estimated at p=0.004 and p=0.03 respectively. CONCLUSION: The Whitening toothpaste has been shown to be significantly more effective in tooth stain removal than the two standard commercial toothpaste formulations.

Stability of undiluted and diluted adenosine at three temperatures in syringes and bags.

The stability of adenosine in various diluents in polypropylene syringes and polyvinyl chloride (PVC) bags at three temperatures was studied. Portions of pooled undiluted adenosine infusion (3 mg/ mL) were stored in 60-mL capped syringes, 20 for each storage condition. Adenosine infusions were prepared by mixing adenosine with 5% dextrose injection, 0.9% sodium chloride injection, lactated Ringer's injection, or 5% dextrose and lactated Ringer's injection to produce a concentration of 0.75 mg/mL. Samples of each infusion were stored in 60-mL capped syringes and 50-mL bags, 20 syringes and 20 bags for each storage condition. Syringes and bags were stored in the dark at 25, 5, and -15 degrees C. At various sampling times, three syringes and three bags of each infusion were removed for visual inspection, pH measurement, and high-performance liquid chromatographic analysis. At 10 and 16 days, fungal growth at 25 degrees C was suspected in the infusions prepared with 5% dextrose injection. For all other samples, there was no evidence of precipitation or change in pH. The concentration of adenosine remained constant in all samples at all storage conditions. Adenosine 3 mg/mL was stable in polypropylene syringes for 7 days at 25 degrees C, 14 days at 5 degrees C, and 28 days at -15 degrees C; adenosine 0.75 mg/ mL in 0.9% sodium chloride injection and in 5% dextrose injection was stable in polypropylene syringes and PVC bags for 16 days at 25, 5, and -15 degrees C; and adenosine 0.75 mg/mL in lactated Ringer's injection and in 5% dextrose and lactated Ringer's injection was stable in syringes and bags for 14 days at 25, 5, and -15 degrees C.