Purpose: To establish age-related, normal limits of monocular and binocular spatial vision under photopic and mesopic conditions. Methods: Photopic and mesopic visual acuity (VA) and contrast thresholds (CTs) were measured with both positive and negative contrast optotypes under binocular and monocular viewing conditions using the Acuity-Plus (AP) test. The experiments were carried out on participants (age range from 10 to 86 years), who met pre-established, normal sight criteria. Mean and ± 2.5σ limits were calculated within each 5-year subgroup. A biologically meaningful model was then fitted to predict mean values and upper and lower threshold limits for VA and CT as a function of age. The best-fit model parameters describe normal aging of spatial vision for each of the 16 experimental conditions investigated. Results: Out of the 382 participants recruited for this study, 285 participants passed the selection criteria for normal aging. Log transforms were applied to ensure approximate normal distributions. Outliers were also removed for each of the 16 stimulus conditions investigated based on the ±2.5σ limit criterion. VA, CTs and the overall variability were found to be age-invariant up to ~50 years in the photopic condition. A lower, age-invariant limit of ~30 years was more appropriate for the mesopic range with a gradual, but accelerating increase in both mean thresholds and intersubject variability above this age. Binocular thresholds were smaller and much less variable when compared to the thresholds measured in either eye. Results with negative contrast optotypes were significantly better than the corresponding results measured with positive contrast (p < 0.004). Conclusions: This project has established the expected age limits of spatial vision for monocular and binocular viewing under photopic and high mesopic lighting with both positive and negative contrast optotypes using a single test, which can be implemented either in the clinic or in an occupational setting.
Rationale: A higher protein intake is suggested to preserve muscle mass during aging, and may therefore reduce the risk for sarcopenia. We explored whether the amount, type (animal/vegetable) and essential amino acid (EAA) composition of protein intake were associated with 5-year change in mid-thigh muscle cross-sectional area (CSA) in older adults.Methods: Protein intake was assessed at year 2 by a Block food frequency questionnaire in 2,597 participants of the Health ABC study, aged 70–79 y. At year 1 and year 6 mid-thigh muscle CSA (cm2) was measured by computed tomography. Multiple linear regression analysis was used to examine the association between energy adjusted protein residuals (total, animal and vegetable protein) and muscle CSA at year 6, adjusted for muscle CSA at year 1 and potential confounders including prevalent health conditions, physical activity and 5-year change in fat mass. EAAintake was expressed as percentage of total protein intake.Results: Mean protein intake was 0.90 (SD 0.36) g/kg/d and mean 5-year change in muscle CSA was −9.8 (17.0) cm2 (n = 1,561). No association was observed between energy adjusted total (β = −0.00 cm2 ; SE = 0.03; P = 0.98), animal (β = −0.00 cm2; SE = 0.03; P = 0.92), and plant (β = +0.07 cm2; SE = 0.07; P = 0.291) protein intake and muscle CSA at year 6, adjusted for baseline mid-thigh muscle area and potential confounders. No associations were observed for the EAAs.Conclusion: A higher total, animal or vegetable protein intake was not associated with 5 year change in mid-thigh cross sectional area in older adults. This conclusion contradicts some, but not all previous research, therefore optimal protein intake for older adults is currently not known.
A local operating theater ventilation device to specifically ventilate the wound area has been developed and investigated. The ventilation device is combined with a blanket which lies over the patient during the operation. Two configurations were studied: Configuration 1 where HEPA-filtered air was supplied around and parallel to the wound area and Configuration 2 where HEPA-filtered air was supplied from the top surface of the blanket, perpendicular to the wound area. A similar approach is investigated in parallel for an instrument table. The objective of the study was to verify the effectiveness of the local device. Prototype solutions developed were studied experimentally (laboratory) and numerically (CFD) in a simplified setup, followed by experimental assessment in a full scale mock-up. Isothermal as well as non-isothermal conditions were analyzed. Particle concentrations obtained in proposed solutions were compared to the concentration without local ventilation. The analysis procedure followed current national guidelines for the assessment of operating theater ventilation systems, which focus on small particles (<10 mm). The results show that the local system can provide better air quality conditions near the wound area compared to a theoretical mixing situation (proof-of-principle). It cannot yet replace the standard unidirectional downflow systems as found for ultraclean operating theater conditions. It does, however, show potential for application in temporary and emergency operating theaters
