Combining the mechanical ball milling of the carbohydrate and the use of low solvent reaction media for the synthesis of fructose fatty acid esters by immobilized lipases.

Synthesis of carbohydrate fatty acid esters catalyzed by immobilized lipases is a pathway to obtain specific isomers from renewable feedstock, compared to unselective chemical esterification. While the use of low-solvent reaction media (≤ 10 %) offers advantages, the interactive effects of these media with biocatalysts and substrates should be modulated towards high catalytic efficiency and substrate availability. Among the investigated co-solvents, tert-butanol and DMSO in a mixture of lauric acid substrate/co-solvent (90/10; v/v) resulted in high bioconversion yields using either Novozym® 435 or Lipozyme® RM IM, as biocatalysts. Increased hydrophobicity of the Novozym® 435 immobilization support favored bioconversion, while polar substrate surface area enlargement by ball-milling improved productivity through enhancement of fructose availability. A compromise between bioconversion yield (19.7 %) and productivity (9.45 µmol/L min) was obtained in the reactions catalyzed by Novozym® 435 using ball-milled fructose at a concentration of 0.2 mol/L. Combining mechanical ball-milling of the substrates with low-solvent reaction media is expected to enhance and expand enzymatic synthesis of carbohydrate fatty acid esters.

Physical activity and dark skin tone: protective factors against low bone mass in Mexican men.

A cross-sectional study was conducted on 268 Mexican men between the ages of 13 and 80 yr to evaluate the association of clinical factors related with bone mass. Men from high schools, universities, and retirement homes were invited to participate. Body mass index (BMI) was measured, and bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry for L1-L4 and total hip. Factors related to bone mass were assessed by questionnaire and analyzed using a logistic regression model. Demographic factors (age, education, and occupation), clinical data (BMI, skin tone, previous fracture, history of osteoporosis [OP], and history of fractures), and lifestyle variables (diet, physical activity, sun exposure, and smoking) were evaluated. Physical activity (≥ 60 min/5 times a week) reduced the risk for low BMD for age, osteopenia, and OP at the spine and total hip (odds ratio [OR]: 0.276; 95% confidence interval [CI]: 0.099-0.769; p=0.014; and OR: 0.184; 95% CI: 0.04-0.849; p=0.03, respectively). Dark skin tone was a protective factor, decreasing the risk by up to 70%. In this population of healthy Mexican men (aged 13-80 yr), dark skin and physical activity were protective factors against low bone mass.

Bone quality and nutritional status in children with congenital heart defects.

The aim of this study was to evaluate bone quality and nutritional status in children with congenital heart defects (CHDs) using quantitative ultrasound. A cross-sectional study was designed. A population-based sample of 75 children with CHD (age: 0--6yr) from the Department of Pediatric Cardiology at the National Cardiology Institute "Ignacio Chávez" was compared with 106 healthy children during 2009. Weight and height were determined in both groups; bone status was measured at the radius and tibia as speed of sound (SOS). Nutritional status was defined according to the Waterloo and Gómez index. Chi-square test, Student's t-test, and analysis of variance were used to determine the statistical differences. A linear regression analysis adjusted by age, weight, height, type of CHD, and birth weight was made. Both groups were similar in sex distribution, prematurity, and birth weight. Acyanotic cardiopathy with increased pulmonary flow was the most frequent (61.3%). Prevalence of malnutrition was higher in CHD group compared with healthy children (p<0.001), and radius SOS was lower in children with CHD compared with healthy children (3484±180 vs 3575±159m/s, respectively; 95% confidence interval: 39.8--143; p=0.001). A positive correlation was found between CHD and reduced SOS in the adjusted linear regression model, r²=0.455 (p<0.001). Children with CHD have lower SOS radius values compared with healthy children, suggesting reduced bone quality regardless of the nutritional status.