Interactive effects of exercise plus calcium-vitamin D3 on bone strength in older men

The findings from this 18-month, community-based study revealed that an exercise program involving strength training and jumping activities was feasible and effective for improving bone density, muscle mass and strength in older men. There were no additional skeletal benefits derived from consuming a high calcium-vitamin D milk drink.

Cracking and distortion of water jackets in engine blocks

This thesis investigated the cracking and distortion of water jackets in engine blocks. The Taguchi method was utilized to improve production process and in doing so, reducing the scrap of water jacket cores by over 60%. Further, by altering core material and pouring temperature, casting distortion was improved.

Study of calcium and silicon migration in refractory magnesia

Studied the effect calcium and silicon impurities have on magnesia refractories, a material frequently used to line high-temperature furnaces. Advanced analytical techniques identified and mapped these impurities in both raw materials and finished magnesia refractories. This research considerably enhanced understanding of factors influencing refractory properties and quality.

Studies on the properties and the thermal decomposition kinetics of natural rubber prepared with calcium chloride

To evaluate calcium chloride coagulation technology, two kinds of raw natural rubber samples were produced by calcium chloride and acetic acid respectively. Plasticity retention index (PRI), thermal degradation process, thermal degradation kinetics and differential thermal analysis of two samples studied. Furthermore, thermal degradation activation energy, pre-exponential factor and rate constant were calculated. The results show that natural rubber produced by calcium chloride possesses good mechanical property and poor thermo-stability in comparison to natural rubber produced by acetic acid.

Is excess calcium harmful to health?

Most current guidelines recommend that older adults and the elderly strive for a total calcium intake (diet and supplements) of 1,000 to 1,300 mg/day to prevent osteoporosis and fractures. Traditionally, calcium supplements have been considered safe, effective and well tolerated, but their safety has recently been questioned due to potential adverse effects on vascular disease which may increase mortality. For example, the findings from a meta-analysis of randomized controlled trials (currently published in abstract form only) revealed that the use of calcium supplements was associated with an ~30% increased risk of myocardial infarction. If high levels of calcium are harmful to health, this may alter current public health recommendations with regard to the use of calcium supplements for preventing osteoporosis. In this review, we provide an overview of the latest information from human observational and prospective studies, randomized controlled trials and meta-analyses related to the effects of calcium supplementation on vascular disease and related risk factors, including blood pressure, lipid and lipoprotein levels and vascular calcification.

Physical, chemical and biological characterization of membrane fouling

In this chapter, advanced characterization of membrane fouling as a diagnostic tool has been summarized to prevent membrane fouling. Physical, chemical and biological analyses as membrane autopsies are mainly utilized to better understand membrane foulant. The physical characterization gives structure, roughness, charge effect, strength and hydrophobicity of membrane fouling. The chemical methods provide qualitative and quantitative measurements of different inorganic and organic matter. The biological properties present the spatial biofilm distribution, structure of dominant microorganisms and isolation and identification of microorganisms. In addition, detailed membrane foulant types are reviewed in terms of structure, roughness, hydrophobicity, charge effect, strength, calcium, magnesium, aluminum, iron, silicate, particle, functional group, biopolymer, humic acid, polysaccharide, structural composition, biofilm structure, microorganism and foulant interaction.

Calcium intakes among Australian women : Geelong Osteoporosis Study

Background: Dietary calcium deficiency may be a risk factor for osteoporosis.

Aims: To estimate habitual calcium intakes and prevalence of calcium supplementation among free-living Australian women and validate a calcium-specific food-frequency questionnaire.

Methods: Calcium intakes for 1045 randomly selected women (20–92 years) were estimated by questionnaire which was tested against estimates from four day weighed records kept by 32 randomly selected women.

Results: The mean difference between calcium estimates was not statistically significantly different from zero (mean difference=121 mg; standard deviation of differences=357 mg; p>0.05). There was moderate agreement (weighted κ=0.4) between methods in ranking subjects into tertiles of calcium intake. Mean dietary calcium intakes were 615 mg/day for 20–54 years, 646 mg/day for 55–92 years and 782 mg/day for lactating women. Seventy-six per cent of women aged 20–54 years, 87% of older and 82% of lactating women had intakes below the recommended dietary intake (RDI). There was no association detected between calcium intake and age. Dairy foods provided 79.0% of dietary calcium intake. Calcium supplements were used by 6.6% and multivitamins by a further 4.3% of women. Supplementation was independent of dietary calcium intake and more likely used by postmenopausal women.

Conclusions: Our results suggest that 76% of women consume less than the RDI even when supplemental calcium is included. Furthermore, 14% have less than the minimal requirement of 300 mg/day and would, therefore, be in negative calcium balance and at risk of bone loss. Despite advertising campaigns promoting better nutrition and increased awareness of osteoporosis, many women are failing to achieve an adequate calcium intake.