Development of microstructure and mechanical properties during annealing of a cold-swaged Co-Cr-Mo alloy rod.

In this study, we investigated the evolution of the microstructure and mechanical properties during annealing of a cold-swaged Ni-free Co-Cr-Mo alloy for biomedical applications. A Co-28Cr-6Mo-0.14N-0.05C (mass%) alloy rod was processed by cold swaging, with a reduction in area of 27.7%, and then annealed at 1173-1423K for various periods up to 6h. The duplex microstructure of the cold-swaged rod consisted of a face-centered cubic γ-matrix and hexagonal closed-packed ε-martensite developed during cold swaging. This structure transformed nearly completely to the γ-phase after annealing and many annealing twin boundaries were observed as a result of the heat treatment. A small amount of the ε-phase was identified in specimens annealed at 1173K. Growth of the γ-grains occurred with increasing annealing time at temperatures ≥1273K. Interestingly, the grain sizes remained almost unchanged at 1173K and a very fine grain size of approximately 8µm was obtained. The precipitation that occurred during annealing was attributed to the limited grain coarsening during heat treatment. Consequently, the specimens treated at this temperature showed the highest tensile strength and lowest ductility among the specimens prepared. An elongation-to-failure value larger than 30% is sufficient for the proposed applications. The other specimens treated at higher temperatures possessed similar tensile properties and did not show any significant variations with different annealing times. Optimization of the present rod manufacturing process, including cold swaging and interval annealing heat treatment, is discussed.

Effectiveness of a Nutrition Education Program to Improve Children's Chewing Habits.

This quasi-experimental study determined whether the nutrition education program we developed to promote chewing food properly influenced children's chewing habits successfully. Four kindergarten classes in Japan (150 children, aged 5-6 years) were studied; one class received the educational program in the classroom and at home (Group A) and three classes received the program in the classroom only (Group B). The educational program was integrated into the classes' daily curriculum for five weeks. It included storytelling with large picture books, chewing consciously while eating lunch, singing a song with gestures, and greetings before and after meals (both groups). Group A also used a paper textbook and was provided information by the leaflet to encourage guardians to implement the program at home. Chewing habits before and after intervention were evaluated: (1) guardians completed seven questionnaire items related to chewing habits and chewing movement and (2) the number of chews and time spent eating the test meal were measured by a portable chewing sensor. Both approaches improved the children's chewing habits; however, no difference was found between the two groups. We concluded that this intervention could be used to improve chewing habits in young children even without active involvement of their guardians.

Dietary patterns affect occlusal force but not masticatory behavior in children.

AIM: In this study, we conducted a dietary assessment of the subjects and investigated the relationship of energy, nutrients and food intake to the indices of masticatory ability and masticatory behavior for identifying the differences in their association with dietary patterns. METHODS: The subjects were 61 5-y-old children, of whom 45 were included in the final analysis. Occlusal force was measured as an index of masticatory ability. To measure masticatory behavior, the number of chews and time taken for eating the test meal were measured. The subjects' food intake was determined by a food record completed by their guardians. The food intake was evaluated using a newly produced list of 90 foods thought to affect chewing, in addition to which we made two subsets of its food groups containing an abundance of insoluble dietary fiber. RESULTS: Significant positive correlations were found between occlusal force and intake of dietary fibers, vegetables, set A food group, and set B food group (r=0.312-0.354). Significant differences were found in occlusal force by tertile groups for dietary fibers, vegetables, the 90 listed items, set A food group, and set B food group. In contrast, there was no significant correlation between the indices of masticatory behavior (the time-adjusted number of chews and time taken for eating the test meal) and those of dietary intake. CONCLUSION: Indicators of masticatory ability and masticatory behavior have different implications in their association with dietary patterns in children.

Moisture and mineral content of human feces--high fecal moisture is associated with increased sodium and decreased potassium content--.

BACKGROUND: The origin of moisture in diarrhea feces is unknown but may represent the unabsorbed part of intestinal contents or alternatively, body fluid excreted into the digestive canal. If the latter mechanism contributes to moisture in the feces, active transport of water (H2O) associated with ion exchange channels may be involved. OBJECTIVE: To investigate this possibility we measured the content of moisture and minerals (sodium [Na], potassium [K], calcium [Ca], magnesium [Mg], phosphorus [P], zinc [Zn], iron [Fe], copper [Cu] and manganese [Mn]) in feces collected during a 12-d metabolic study on 11 young Japanese female students. DESIGN: The study was carried out as part of a human mineral balance study. The same quantity of food was supplied to each of the subjects throughout the study without consideration of body weight. Fecal specimens were collected throughout the study and were separated into those originating from the diet during the balance period based on the appearance of the ingested colored marker in the feces. RESULTS: The moisture content of the feces ranged between 53 and 92%. Na content in the feces was low and stable when the moisture content was below 80%, whereas it increased up to serum levels when the moisture content increased above 80%. On the other hand, K content increased when compared to dry matter base. However, when comparing concentration/g moisture, K content increased when moisture was below 70%, but decreased when this rose above 70%.