In vivo contact stresses at the radiocarpal joint using a finite element method of the complete wrist joint

A small number of cadaveric studies have been carried out looking at the force transmission through the radiocarpal joint. In this study subject specific finite element models were created of the whole wrist joint using measured biomechanical data to capture the forces acting on the wrist with the hand generating a maximum gripping force

Prediction of risk of fracture in the tibia due to altered bone mineral density distribution resulting from disuse : a finite element study

The disuse-related bone loss that results from immobilisation following injury shares characteristics with osteoporosis in postmenopausal women and the aged, with decreases in bone mineral density (BMD) leading to weakening of the bone and increased risk of fracture. The aim of the study was to use the finite element method to: (i) calculate the mechanical response of the tibia under mechanical load and (ii) estimate the risk of fracture; comparing between two groups, an able bodied (AB) group and spinal cord injury (SCI) patients group suffering from varying degree of bone loss. The tibiae of eight male subjects with chronic SCI and those of four able-bodied (AB) age-matched controls were scanned using multi-slice peripheral Quantitative Computed Tomography. Images were used to develop full three-dimensional models of the tibiae in Mimics (Materialise) and exported into Abaqus (Simulia) for calculation of stress distribution and fracture risk in response to specified loading conditions – compression, bending and torsion. The percentage of elements that exceeded a calculated value of the ultimate stress provided an estimate of the risk of fracture for each subject, which differed between SCI subjects and their controls. The differences in BMD distribution along the tibia in different subjects resulted in different regions of the bone being at high risk of fracture under set loading conditions, illustrating the benefit of creating individual material distribution models. A predictive tool can be developed based on these models, to enable clinicians to estimate the amount of loading that can be safely allowed onto the skeletal frame of individual patients who suffer from extensive musculoskeletal degeneration (including SCI, multiple sclerosis and the ageing population). The ultimate aim would be to reduce fracture occurrence in these vulnerable groups

Long-Term Prognostic Importance of Diabetes After a Myocardial Infarction Depends on Left Ventricular Systolic Function

Objective: This study was performed to understand how left ventricular function modulates the prognostic importance of diabetes after myocardial infarction (MI). Research Design and Methods: Consecutively hospitalized MI patients screened for three clinical trials were followed for a median of 7 years. Multivariable Cox regression models were used to assess the risk of mortality associated with diabetes, and the importance of diabetes was examined independently within defined left ventricular ejection fraction (LVEF) subgroups. Results: A total of 16,912 patients were included; 1,819 (11%) had diabetes. Diabetes and 15% unit depression in LVEF were of similar prognostic importance: hazard ratios (HRs) were 1.45 (95% CI 1.37–1.54) and 1.41 (1.37–1.45) for diabetes and LVEF depression, respectively. LVEF modified the outcomes associated with diabetes, with HRs being 1.29 (1.19–1.40) and 1.61 (1.49–1.74) in patients with LVEF <40% and LVEF ≥40%, respectively (P = 0.03). Conclusions: Patients within the higher LVEF categories have a greater mortality risk attributable to diabetes than patients within the lower LVEF categories

Remote sensing of zooplankton swarms

Zooplankton provide the key link between primary production and higher levels of the marine food web and they play an important role in mediating carbon sequestration in the ocean. All commercially harvested fish species depend on zooplankton populations. However, spatio-temporal distributions of zooplankton are notoriously difficult to quantify from ships. We know that zooplankton can form large aggregations that visibly change the color of the sea, but the scale and mechanisms producing these features are poorly known. Here we show that large surface patches (>1000 km 2 ) of the red colored copepod Calanus finmarchicus can be identified from satellite observations of ocean color. Such observations provide the most comprehensive view of the distribution of a zooplankton species to date, and alter our understanding of the behavior of this key zooplankton species. Moreover, our findings suggest that high concentrations of astaxanthin-rich zooplankton can degrade the performance of standard blue-green reflectance ratio algorithms in operational use for retrieving chlorophyll concentrations from ocean color remote sensing.publishedVersio

Investigation of chlorine radical chemistry in the Eyjafjallajkull volcanic plume using observed depletions in non-methane hydrocarbons

As part of the effort to understand volcanic plume composition and chemistry during the eruption of the Icelandic volcano Eyjafjallajkull, the CARIBIC atmospheric observatory was deployed for three special science flights aboard a Lufthansa passenger aircraft. Measurements made during these flights included the collection of whole air samples, which were analyzed for non-methane hydrocarbons (NMHCs). Hydrocarbon concentrations in plume samples were found to be reduced to levels below background, with relative depletions characteristic of reaction with chlorine radicals (Cl). Recent observations of halogen oxides in volcanic plumes provide evidence for halogen radical chemistry, but quantitative data for free halogen radical concentrations in volcanic plumes were absent. Here we present the first observation-based calculations of Cl radical concentrations in volcanic plumes, estimated from observed NMHC depletions. Inferred Cl concentrations were between 1.3 × 10 and 6.6 × 10 Cl cm. The relationship between NMHC variability and local lifetimes was used to investigate the ratio between OH and Cl within the plume, with [OH]/[Cl] estimated to be ∼37. Copyright 2011 by the American Geophysical Union

Prevalence of allergic sensitization to storage mites in Northern Europe.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadBACKGROUND: Allergic sensitization to storage mites has mostly been related to occupational exposures like farming, grain/cattle handling, whereas for non-occupational settings, storage mite sensitization has been attributed to cross-reactivity with house dust mite (HDM) allergens. OBJECTIVE: We aimed to describe the prevalence of allergic sensitization to storage mites, co-sensitization to HDM allergens and respiratory symptoms in Denmark, Iceland, Norway and Sweden. METHODS: The population comprised of 1180 participants born 1945-1972 of the third follow-up of the population-based cohort European Community Respiratory Health Survey (ECRHS) in Aarhus, Bergen, Reykjavik and Uppsala. A clinical examination included skin prick tests (SPT) to Lepidoglyphus destructor, Tyrophagus putrescentiae, Acarus siro and common inhalant allergens, as well as standardized interviews. RESULTS: 8% were sensitized to HDM and 10% to storage mite, with some variation by study centre: Reykjavik 13%, Bergen 8% and Aarhus 7%. In Uppsala, only L destructor (3%) was measured. Storage mite sensitization was higher among men (11%) than women (8%). Among storage mite sensitized, 44% were also sensitized to HDM. Storage mite sensitization was associated with asthma and nasal allergies, but not with age, education, pet keeping or place of upbringing. CONCLUSIONS AND CLINICAL RELEVANCE: In this Northern European population-based study, allergic sensitization to storage mite was as common as HDM sensitization. Storage mite sensitization was, independently of HDM sensitization, associated with respiratory symptoms and asthma. Our findings suggest that storage mite sensitization should be evaluated with regard to inclusion into the common inhalant allergen panel in Northern Europe.Landspitali University Hospital Research Fund University of Iceland Research Fund ResMed Foundation, California, USA Orkuveita Reykjavikur (Geothermal plant) Vegageroin (The Icelandic Road Administration (ICERA)) Swedish Heart-Lung Foundation Swedish Asthma and Allergy Association Swedish Association against Lung and Heart Disease Swedish Research Council for health, working life and welfare (FORTE) Research Council of Norway Western Norway Regional Health Authorities grant Bergen Medical Research Foundation Faculty of Health, Aarhus University Wood Dust Foundatio

Worldwide patterns of bronchodilator responsiveness: results from the Burden of Obstructive Lung Disease study.

To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.Criteria for a clinically significant bronchodilator response (BDR) are mainly based on studies in patients with obstructive lung diseases. Little is known about the BDR in healthy general populations, and even less about the worldwide patterns. 10 360 adults aged 40 years and older from 14 countries in North America, Europe, Africa and Asia participated in the Burden of Obstructive Lung Disease study. Spirometry was used before and after an inhaled bronchodilator to determine the distribution of the BDR in population-based samples of healthy non-smokers and individuals with airflow obstruction. In 3922 healthy never smokers, the weighted pooled estimate of the 95th percentiles (95% CI) for bronchodilator response were 284 ml (263 to 305) absolute change in forced expiratory volume in 1 s from baseline (ΔFEV(1)); 12.0% (11.2% to 12.8%) change relative to initial value (%ΔFEV(1i)); and 10.0% (9.5% to 10.5%) change relative to predicted value (%ΔFEV(1p)). The corresponding mean changes in forced vital capacity (FVC) were 322 ml (271 to 373) absolute change from baseline (ΔFVC); 10.5% (8.9% to 12.0%) change relative to initial value (ΔFVC(i)); and 9.2% (7.9% to 10.5%) change relative to predicted value (ΔFVC(p)). The proportion who exceeded the above threshold values in the subgroup with spirometrically defined Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 2 and higher (FEV(1)/FVC <0.7 and FEV(1)% predicted <80%) were 11.1%, 30.8% and 12.9% respectively for the FEV(1)-based thresholds and 22.6%, 28.6% and 22.1% respectively for the FVC-based thresholds. The results provide reference values for bronchodilator responses worldwide that confirm guideline estimates for a clinically significant level of BDR in bronchodilator testing.ALTANA Aventis AstraZeneca Boehringer-Ingelheim Chiesi GlaxoSmithKline Merck Novartis Pfizer Schering-Plough Sepracor University of Kentucky Boehringer Ingelheim Schering Ploug

Assessing hydrological controls on the lithium isotope weathering tracer

To investigate the impact of riverine discharge and weathering intensity on lithium isotopes (δ7Li) in a mono-lithological terrain, this study examines the dissolved load and leached suspended load (exchangeable, oxide, and clay fractions) from Icelandic rivers spanning a wide range of discharge, weathering rates, and weathering intensity. The δ7Lidissolved co-varies inversely with the discharge, confirming that water-rock interaction time is a primary control on the secondary mineral formation that fractionates Li isotopes. The “boomerang” shape observed in global rivers between the weathering intensity (i.e. W/D = weathering rate/denudation rate) and δ7Lidissolved also exists for these basaltic rivers at low to medium W/D. However, these rivers do not extend to such low δ7Lidissolved values as seen in the global compilation at low W/D, indicating that there is a lithological control on this relationship arising from the type of the lithology-specific secondary minerals forming and their precipitation rates. In addition, the Δ7Lix-dissolved between each leached solid phase and the dissolved load also co-varies with discharge. At low discharge (long water-rock interaction times), Δ7Lix-dissolved values agree with experimentally-determined equilibrium values, whereas less fractionated values are observed at higher discharge (shorter water-rock interaction times). As a result, there is a different relationship between W/D and Δ7Liclay-source in this basaltic terrain than previously reported from global multi-lithological river sediment samples, with clay leachates from Iceland more closely mimicking the boomerang shape of the dissolved load. However, the relationship between δ7Li and weathering processes is complicated because the fractionation between the clay fraction and the dissolved load is not constant but varies with both W/D and discharge. Overall, this study confirms the utility of Li isotopes as a tracer of modern and palaeo-weathering processes, and also has important implications for the specific interpretations of detrital δ7Li values, which may be more sensitive to weathering parameters than previously thought