Acoustic and ultrasonic tissue characterization--assessment of osteoporosis.

Osteoporosis, often termed the 'silent epidemic', has been defined as 'a decrease in bone mass and architectural deterioration of bone tissue, leading to enhanced bone fragility and consequent increase in fracture risk'. In the United Kingdom alone, the annual health costs are in excess of 750 million Pounds, with 60,000 patients suffering a hip fracture each year. A quarter of these will die within 12 months of their fracture, half of the remainder will never regain independent living. The established procedure for assessing the risk of osteoporotic fracture is via bone mineral density (BMD) assessment using dual-energy X-ray absorptiometry (DXA). However, DXA is an expensive technique and is not widely available. Within the past 15 years, ultrasound assessment of bone has rapidly advanced in scientific understanding, technical development and clinical utility. Measurements of cancellous bone (particularly at the calcaneus) are generally performed in preference to those of cortical bone (tibial cortex). There are currently 15 commercial systems available and over 3500 systems are in use world-wide. The low cost and portability offered by ultrasound systems should enable an integrated community-based screening programme to be established in the near future. Ultrasound measurements of bone are generally obtained using transmission rather than pulse-echo techniques owing to its highly attenuating nature. Ultrasound velocity and attenuation measurements are utilized. For velocity, there are well-defined fundamental relationships describing the dependence upon the elasticity and density of bone.     

Isolation and characterization of inositol sphingophospholipids from Phytophthora parasitica Dastur

Several inositol sphingophospholipids (ISPL) were isolated from mycelia of Phytophthora parasitica Dastur, a phytopathogenic fungus of carnation. The ISPL structures were determined by fast atom bombardment. All ISPL consisted of ceramides linked to inositol phosphate. We investigated the effect of growth conditions on the ISPL produced in four different media that are commonly used for fungal cultures. We showed that P. parasitica Dastur synthesized four major classes of compounds with molecular weights of M_r=751, 807, 835, and 849 containing the 16:1 base and the 16:0 or 20:0 or 22:0 or 22h:1 N-acyl group. The relative abundance of the different ISPL is dependent on growth conditions. This work is dedicated to the memory of Professor G. Michel.     

Health status recovery at one year in children injured in a road accident: A cohort study

Despite the frequency of traumatic injuries due to road accidents and potential importance of identifying children at risk of impaired recovery one year after a road accident, there is a lack of data on long-term recovery of health status, except in children with severe traumatic brain injury. The aim of the present study was to evaluate predictive factors of recovery in children one year after road traffic injuries. The prospective cohort study was composed of children aged <16 years, admitted to public or private sector hospitals in the Rhône administrative area of France following a road accident. Recovery of health status one year after the accident and information concerning quality of life and the consequences of the accident for the child or family 1 year after the accident were collected by questionnaire, usually completed by the parents. Victims were in majority male (64.6%) and had mild or moderate injuries (81.9% with Maximum Abbreviated Injury Scale (M-AIS) <3). One year after the accident, 75.0% of the mild-to-moderate and 34.8% of the severe cases estimated health status as fully recovered. After adjustment, severity score (M-AIS ≥ 3) and lower limb injury (AIS > 1) were associated with incomplete recovery of health status: weighted odds ratio (OR_w), 4.3 [95% confidence interval (95% CI), 1.3–14.6] and OR_w, 6.5 [95% CI, 1.9–21.7], respectively. Recovery status correlated significantly with quality of life physical scores (r = 0.46), especially body pain (r = 0.48) and role/social–physical (r = 0.50) and, to a lesser extent, quality of life psychosocial scores (r = 0.21). In a cohort of children injured in a road accident, those with high injury severity score and those with lower limb injuries are less likely to recover full health status by 1 year. Impaired health status was associated with a lower physical quality of life score at 1 year.     

The aluminum/polythiophene interface: a case study in molecular electronics and computational chemistry

Conjugated polymer/metal interfaces are formed during the construction of thin-film polymer light-emitting diodes. The nature of the interface may affect device operation. This paper describes the use of computational chemical methods in modelling the interface formed when aluminum is deposited onto a thin film of polythiophene.     

Processing-Property interactions in vinylidene fluoride/trifluoroethylene random copolymers

The effect of flow history, processing temperature, and exit draw ratio have been studied for copolymers of vinylidene fluoride/trifluoroethylene of molar compositions 66/34 and 75/25%. The copolymers were extruded through an impinging channels film die which produces a mixed extension and shearing flow as well as a slit die. Stress fields during flow were measured using flow birefringence. Differential Scanning Calorimetry (DSC) analyses were used to characterize the thermal behavior; and flat film and Wide Angle X-ray Scattering (WAXS) were used to evaluate the crystal structure and morphology of the extrudates. Extensional melt stresses on the order of 6.35 × 10⁵ Pa were necessary to induce sufficient orientation for crystallization of water-cooled 66/34 mol % copolymers into the all-trans configuration. Preorientation of the melt by extensional stresses enhanced the transformation of the 3/1 helical to an all-trans structure in the 66/34 copolymer as well as producing a more compact unit cell in the 75/25 mol % copolymer leading to as much as a 7°C higher Curie transition temperature.     

Estimation of the degree of polymerization of condensed tannins of some wild fruits of Zimbabwe (Uapaca kirkiana and Ziziphus mauritiana) using the modified vanillin‐HCl method

Methanol and glacial acetic acid were compared for their effect in the vanillin assay for tannins. The time taken for the development of colour was followed using a spectrophotometer. By reacting vanillin and condensed tannins in the presence of acetic acid, the time for the development of the chromogenic substance was reduced approximately threefold compared with the time taken in the presence of methanol. The degree of polymerization was followed by reacting a catechin standard, the tannin of the Uapaca kirkiana and Ziziphus mauritiana, with vanillin in acetic acid medium at 30 °C and measuring absorbance at intervals. The values obtained suggested between 4 and 10 monomer units of catechin per polymer of tannins for the different portions of the two fruits. Copyright © 2005 Society of Chemical Industry     

Lipolytic enzyme and phospholipid level changes in intraoperative salvaged blood

Autotransfusion is becoming increasingly popular, mainly because it eliminates the risk of disease transmission. One of the techniques available is intra-operative blood salvage and retransfusion with or without washing of the collected blood. The blood collected during this process is subjected to a variety of chemical and physical insults which can alter the normal composition of the plasma by activating plasma and cellular homeostatic mechanisms. In this study, we measured the plasma levels of total phospholipids, lysolecithin and non-esterified fatty acids, and the lipolytic enzymes phospholipase A2 (PLA2) and lipase in the salvaged blood before and after washing. In the unwashed salvaged blood the mean levels of PLA2, non-esterified fatty acids and lysophospholipids increased by 144, 96 and 149%, respectively, while those of total phospholipids and lipase did not change to any extent. All these substances were reduced to well below the patients circulating plasma levels by washing the collected blood. The changes indicate that the lipid profile of salvaged blood is significantly altered and that potentially dangerous substances such as PLA2 and its metabolites, lysolecithin and non-esterified fatty acids, are present in increased amounts. Washing the blood is recommended prior to reinfusion.