Zirconium, calcium, and strontium contents in magnesium based biodegradable alloys modulate the efficiency of implant-induced osseointegration

Development of new biodegradable implants and devices is necessary to meet the increasing needs of regenerative orthopedic procedures. An important consideration while formulating new implant materials is that they should physicochemically and biologically mimic bone-like properties. In earlier studies, we have developed and characterized magnesium based biodegradable alloys, in particular magnesium-zirconium (Mg-Zr) alloys. Here we have reported the biological properties of four Mg-Zr alloys containing different quantities of strontium or calcium. The alloys were implanted in small cavities made in femur bones of New Zealand White rabbits, and the quantitative and qualitative assessments of newly induced bone tissue were carried out. A total of 30 experimental animals, three for each implant type, were studied, and bone induction was assessed by histological, immunohistochemical and radiological methods; cavities in the femurs with no implants and observed for the same period of time were kept as controls. Our results showed that Mg-Zr alloys containing appropriate quantities of strontium were more efficient in inducing good quality mineralized bone than other alloys. Our results have been discussed in the context of physicochemical and biological properties of the alloys, and they could be very useful in determining the nature of future generations of biodegradable orthopedic implants.

Rhythmic throat oscillations in nesting green turtles (Chelonia mydas)

Female green turtles (Chelonia mydas) were monitored for signs of throat movements/oscillations when attempting to nest at Ascension Island in the S5outh Atlantic. Throat oscillations occurred during all stages of the nesting process, with the mean frequency ranging from 10.9 to 36.1 oscillations/min, while the mean breathing rate for different stages during nesting activity ranged from 1.3 to 2.8 breaths/min.

Food choices that achieve calcium adequacy in older women

Aim
In a sample of older women, we assessed the proportion who met the estimated average requirement (1100 mg/day) for calcium and the dietary food choices that achieved calcium adequacy. We also assessed if the diets adequate in dietary calcium were consistent with the other dietary recommendations for health.

Methods
Baseline data from women aged 50+ years who were recruited for dietary intervention studies were included as a proxy for usual intake. Analyses of usual food and nutrient intake were derived from two 24-hour recalls.

Results
Women (n = 145) aged 50+ years (mean age 59.3 (SD 5.5) years, mean calcium intake of 815 (323) mg calcium/day) participated. Approximately one-fifth met the estimated average requirement for calcium (21%, n = 31); among this group, dairy products contributed to 61% of calcium intake (mean 2.8 (SD 1.0) servings/day). Milk contributed 33% (425 mg) of total dietary calcium. Three per cent consumed skim milk only. Both groups (calcium adequate/inadequate) exceeded the suggested dietary target (≤10%) recommended for percent energy from saturated fat, 13.4% (3.7%) and 11.7% (3.5%), respectively. In the adequate group, if skim milk replaced full-fat and reduced-fat milk, then percent energy from saturated fat would fall by 3% (from 13.4% of energy to 10.4% of energy).

Conclusions
Consumption of at least 2.8 servings/day of dairy products is likely to ensure an adequate calcium intake (>1100 mg) in women over 50 years. However, to ensure saturated fat remains at recommended levels, usual consumption of full-fat and reduced-fat milk should be replaced with skim milk.

Antiarthritic and chondroprotective activity of Lakshadi Guggul in novel alginate-enclosed chitosan calcium phosphate nanocarriers

Aim: