Low vitamin D status adversely affects bone health parameters in adolescents

Background: The effects of subclinical vitamin D deficiency on bone mineral density (BMD) and bone turnover in adolescents, especially in boys, are unclear.

Objective: We aimed to investigate the relations of different stages of vitamin D status and BMD and bone turnover in a representative sample of adolescent boys and girls.

Design: BMD was measured by dual-energy X-ray absorptiometry at the nondominant forearm and dominant heel in a random sample of 12- (n = 260) and 15-y-old (n = 239) boys and 12- (n = 266) and 15-y-old (n = 250) girls. Serum 25-hydroxyvitamin D, parathyroid hormone, osteocalcin, and type I collagen cross-linked C-telopeptide were assessed by using enzyme-linked immunoassays. Relations between vitamin D status and bone health indexes were assessed by using regression modeling.

Results: Using multivariate regression to adjust for potential physical, lifestyle, and dietary confounding factors, we observed that 12-and 15-y-old girls with high vitamin D status (>= 74.1 nmol/L) had significantly greater forearm (but not heel) BMD (beta = 0.018; SE = 0.008; P < 0.05 for each age group) and lower serum parathyroid hormone concentrations and bone turnover markers than did those with low vitamin D status. These associations were evident in subjects sampled throughout the year and in winter only. There was no significant relation between vitamin D status and BMD in boys.

Conclusions: Maintaining serum 25-hydroxyvitamin D concentrations above approximate to 50 nmol/L throughout the year may be a cost-effective means of improving bone health. Increased emphasis on exploring strategies for improving vitamin D status in adolescents is needed.

Investigation of swelling and network parameters of poly(ethylene glycol)-crosslinked poly(methyl vinyl ether-co-maleic acid) hydrogels

The influence of poly(ethylene glycol) (PEG) plasticiser content and molecular weight on the physicochemical properties of films cast from aqueous blends of poly(methyl vinyl ether-co-maleic acid) was investigated using thermal analysis, swelling studies, scanning electron microscopy (SEM) and attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy. FTIR spectroscopy revealed a shift of the C{double bond, long}O peak from 1708 to 1731 cm, indicating that an esterification reaction had occurred upon heating, thus producing crosslinked films. Higher molecular weight PEGs (10,000 and 1000 Da, respectively), having greater chain length, producing hydrogel networks with lower crosslink densities and higher average molecular weight between two consecutive crosslinks. Accordingly, such materials exhibited higher swelling rates. Hydrogels crosslinked with a low molecular weight PEG (PEG 200) showed rigid networks with high crosslink densities and, therefore, lower swelling rates. Polymer:plasticizer ratio alteration did not yield any discernable patterns, regardless of the method of analysis. The polymer-water interaction parameter (?) increased with increases in the crosslink density. SEM studies showed that porosity of the crosslinked films increased with increasing PEG MW, confirming what had been observed with swelling studies and thermal analysis, that the crosslink density must be decreased as the M of the crosslinker is increased. Hydrogels containing PMVE/MA/PEG 10,000 could be used for rapid delivery of drug, due to their low crosslink density. Moderately crosslinked PMVE/MA/PEG 1000 hydrogels or highly crosslinked PMVE/MA/PEG 200 systems could then be used in controlling the drug delivery rates. We are currently evaluating these systems, both alone and in combination, for use in sustained release drug delivery devices. © 2008 Elsevier Ltd. All rights reserved.

What do men understand about lifetime risk following genetic testing?:The effect of context and numeracy.

Genetic testing for gene mutations associated with specific cancers provides an opportunity for early detection, surveillance, and intervention (Smith, Cokkinides, & Brawley, 2008). Lifetime risk estimates provided by genetic testing refer to the risk of developing a specific disease within one's lifetime, and evidence suggests that this is important for the medical choices people make, as well as their future family and financial plans. The present studies tested whether adult men understand the lifetime risks of prostate cancer informed by genetic testing. In 2 experiments, adult men were asked to interpret the lifetime risk information provided in statements about risks of prostate cancer. Statement format was manipulated such that the most appropriate interpretation of risk statements referred to an absolute risk of cancer in experiment 1 and a relative risk in experiment 2. Experiment 1 revealed that few men correctly interpreted the lifetime risks of cancer when these refer to an absolute risk of cancer, and numeracy levels positively predicted correct responding. The proportion of correct responses was greatly improved in experiment 2 when the most appropriate interpretation of risk statements referred instead to a relative rather than an absolute risk, and numeracy levels were less involved. Understanding of lifetime risk information is often poor because individuals incorrectly believe that these refer to relative rather than absolute risks of cancer.

Influence of a pore-forming agent on swelling, network parameters, and permeability of poly(ethylene glycol)-crosslinked poly(methyl vinyl ether-co-maleic acid) hydrogels:Application in transdermal delivery systems

We characterized hydrogels, prepared from aqueous blends of poly(methyl vinyl ether-co-maleic acid) (PMVE/MA) and poly(ethylene glycol) (PEG 10,000 Daltons) containing a pore-forming agent (sodium bicarbonate, NaHCO ). Increase in NaHCO content increased the equilibrium water content (EWC) and average molecular weight between crosslinks (M ) of hydrogels. For example, the %EWC was 731, 860, 1109, and 7536% and the M was 8.26, 31.64, 30.04, and 3010.00 × 10 g/mol for hydrogels prepared from aqueous blends containing 0, 1, 2, and 5% w/w of NaHCO , respectively. Increase in NaHCO content also resulted in increased permeation of insulin. After 24 h, percentage permeation was 0.94, 3.68, and 25.71% across hydrogel membranes prepared from aqueous blends containing 0, 2, and 5% w/w of NaHCO , respectively. Hydrogels containing the pore-forming agent were fabricated into microneedles (MNs) for transdermal drug delivery applications by integrating the MNs with insulin-loaded patches. It was observed that the mean amount of insulin permeating across neonatal porcine skin in vitro was 20.62% and 52.48% from hydrogel MNs prepared from aqueous blends containing 0 and 5% w/w of NaHCO . We believe that these pore-forming hydrogels are likely to prove extremely useful for applications in transdermal drug delivery of biomolecules. © 2012 Wiley Periodicals, Inc.

Limitations of Global Kinetic Parameters for Automotive Application

With emission legislation becoming ever more stringent, automotive companies are forced to invest heavily into solutions to meet the targets set. To date the most effective way of treating emissions is through the use of catalytic converters. Current testing methods of catalytic converters whether being tested on a vehicle or in a lab reactor can be expensive and offer little information about what is occurring within the catalyst. It is for this reason and the increased price of precious metal that kinetic modelling has become a popular alternative to experimental testing.

Entanglement Spectrum, Critical Exponents and Order Parameters in Quantum Spin Chains

We investigate the entanglement spectrum near criticality in finite quantum spin chains. Using finite size scaling we show that when approaching a quantum phase transition, the Schmidt gap, i.e., the difference between the two largest eigenvalues of the reduced density matrix ?1, ?2, signals the critical point and scales with universal critical exponents related to the relevant operators of the corresponding perturbed conformal field theory describing the critical point. Such scaling behavior allows us to identify explicitly the Schmidt gap as a local order parameter.

Simultaneous Gas Storage and Catalytic Gas Production Using Zeolites-A New Concept for Extending Lifetime Gas Delivery

Copper containing MCM-41 materials can be used to both store gaseous nitric oxide and to catalytically produce nitric oxide from nitrite. The active species for the reaction is copper (I). Addition of cysteine to the solution in contact with the material has different effects depending on how much Cu(I) is present. This is a new method of extending the lifetime of gas delivery from a gas storage material.

Assessing Lifetime Homes Standards and Part M Building Regulations for Housing Design in the UK

The aims of this article are to examine Lifetime Home Standards (LTHS) and Part M of the UK Building Regulations and to discuss how relevant and successful they are. The UK government expects all new homes to be built to LTHS by 2013. This is increasingly important with an ageing population. The home environment can enable independence and provide a therapeutic place for everyone. As Part M of the building regulations are compulsory in all housing and LTHS are mandatory for public sector housing, a review of research articles was undertaken on these standards. The paper begins with a brief background on accessibility regulations, followed by a critical review of the standards that takes the body of literature that has been written around them into account. This review suggests that the standards should be improved and that designers and architects face challenges to creatively incorporate them into housing design.