Does a novel X-ray imaging technology provide a substantial radiation dose reduction for patients in trans-catheter aortic valve implantation procedures?

Purpose: Modern interventional X-ray equipment employs image processing to permit reduction in radiation whilst retaining sufficient image quality. The aim of this study was to investigate whether our recently-installed system (AlluraClarity, Philips Healthcare) which contains advanced real-time image noise reduction algorithms and anatomy-specific X-ray optimization (beam filtering, grid switch, pulse width, spot size, detector and image processing engine), affected patient procedure dose and overall procedure duration in routine trans-catheter aortic valve implantation (TAVI) procedures. Methods: Patient dose for 42 TAVI patients from the AlluraClarity cardiac catheterisation lab and from a reference system (Axiom Artis, Siemens Healthcare) in the same cardiology department was recorded. Median values from the two X-ray systems were compared using the Wilcoxon statistical test. Results: Total patient procedure dose medians were 4016 and 7088 cGy cm2 from the AlluraClarity and reference systems respectively. AlluraClarity median patient doses were 3405 cGy cm2 and 783.5 cGy cm2 from fluoroscopy and digital image acquisition respectively. Reference median patient doses were 4928 cGy cm2 and 2511 cGy cm2 from fluoroscopy and digital image acquisition respectively. All differences in patient dose were significant at the 5% level. Median total fluoroscopy times [min:sec] were 19:57 and 20:20 for the AlluraClarity and reference systems respectively. Conclusion: The AlluraClarity cardiac catheterisation lab had 43% lower total patient procedure dose for TAVI patients than the reference lab; fluoroscopy and digital image acquisition doses were 31% and 69% lower respectively. In terms of total fluoroscopy time, there was no statistically significant difference between the two labs

Machine vision image quality measurement in cardiac x-ray imaging

The purpose of this work is to report on a machine vision approach for the automated measurement of x-ray image contrast of coronary arteries filled with iodine contrast media during interventional cardiac procedures. A machine vision algorithm was developed that creates a binary mask of the principal vessels of the coronary artery tree by thresholding a standard deviation map of the direction image of the cardiac scene derived using a Frangi filter. Using the mask, average contrast is calculated by tting a Gaussian model to the greyscale profile orthogonal to the vessel centre line at a number of points along the vessel. The algorithm was applied to sections of single image frames from 30 left and 30 right coronary artery image sequences from different patients. Manual measurements of average contrast were also performed on the same images. A Bland-Altman analysis indicates good agreement between the two methods with 95% confidence intervals -0.046 to +0.048 with a mean bias of 0.001. The machine vision algorithm has the potential of providing real-time context sensitive information so that radiographic imaging control parameters could be adjusted on the basis of clinically relevant image content

Fast predictive expression platform – CHO-K1 with transposase

The Mammalian Expression group in Therapeutics Discovery Research produces panels of therapeutic candidates in high-throughput (HT) for early stage screening in addition to generating larger productions that are used for manufacturability assessment, pre-clinical PK, and efficacy studies. As our molecule types expand from monoclonal antibodies to include various bispecific modalities, the ability to predict how a molecule will behave in our stable manufacturing host becomes more difficult. To more quickly predict characteristics and manufacturability of our candidate therapeutics, we are developing in-house stable expression systems. The transposase is a mobile genetic element that efficiently transposes between vectors and chromosomes via a “cut and paste” mechanism. Because the transposase facilitates non-random, efficient genetic integration, we investigated the possible incorporation of this technology into our current in-house transient expression vector system. We have observed that its stable-like integration properties provide us with a foundation for enabling a short production time, comparable with a transient expression system, while generating proteins with attributes that are predictive of our manufacturing system. This approach has been validated and implemented with our CHO-K1 stable expression system. With this technology, we are able to reliably generate the diverse array of therapeutic candidate modalities in a high-throughput format while achieving higher predictability of material derived from our manufacturing hosts

An experimental study of ZigBee for body sensor networks

We present an experimental performance evaluation of ZigBee networks in the context of data-intensive body sensor networks (BSNs). IEEE 802.15.4/ZigBee devices were mainly developed for use in wireless sensors network (WSN) applications; however, due to characteristics such as low power and small form factor, they are also being widely used in BSN applications, making it necessary to evaluate their suitability in this context. The delivery ratio and end-to-end delay were evaluated, under contention, for both star and tree topologies. The reliability of the ZigBee network in a star topology without hidden nodes was very good (delivery ratio close to 100%), provided the acknowledgement mechanism was enabled. On the other hand, the performance in a tree topology was degraded due to router overload and the activation of the route maintenance protocol triggered by periods of high traffic load. The effect of the devices’ clock drift and hidden nodes on the reliability of the star network was modeled and validated through experimental tests. In these tests, the worst-case delivery ratio when the acknowledgment is used decreased to 90% with two sensor nodes, while for the non-acknowledged mode the result was of 13%. These results show that a mechanism for distributing the nodes’ traffic over the time is required to avoid BSN performance degradation caused by router overload, clock drift and hidden node issues.Fundação para a Ciência e Tecnologi

CO2 sequestration in basaltic rocks in Iceland: Development of a piston-type downhole sampler for CO2 rich fluids and tracers

The reduction of atmospheric CO2 is one of the challenges that scientists face today. University of Iceland, Reykjavik Energy, CNRS in Toulouse and Columbia University have started a cooperative project called CarbFix (www.carbfix.com) aiming at CO2 mineral sequestration into basalts at Hellisheidi, SW Iceland. Gaseous CO2 will be injected into a borehole where it will be carbonated with Icelandic groundwater. The CO2 charged injection fluid will be released into the target aquifer at ca. 500 m depth at about 35°C and 40 bar. The aim is to permanently bind CO2 into carbonates upon water-rock interaction. In order to evaluate the hydro-geochemical patterns and proportions of CO2 mineralization in the aquifer, full scale monitoring is needed. This will involve monitoring of conservative and gas tracers injected with the carbonated fluid, isotope ratios and major and trace elemental chemistry. A crucial issue of the monitoring is the quality of the sampling at depth and under pressure. Commonly, gas bubbles are observed when using commercial downhole samplers (bailers) and in order to avoid this problem, a piston-type downhole bailer was designed, constructed and tested as part of the project

Excitons in T-shaped quantum wires

We calculate energies, oscillator strengths for radiative recombination, and two-particle wave functions for the ground state exciton and around 100 excited states in a T-shaped quantum wire. We include the single-particle potential and the Coulomb interaction between the electron and hole on an equal footing, and perform exact diagonalisation of the two-particle problem within a finite basis set. We calculate spectra for all of the experimentally studied cases of T-shaped wires including symmetric and asymmetric GaAs/Al$_{x}$Ga$_{1-x}$As and In$_{y}$Ga$_{1-y}$As/Al$_{x}$Ga$_{1-x}$As structures. We study in detail the shape of the wave functions to gain insight into the nature of the various states for selected symmetric and asymmetric wires in which laser emission has been experimentally observed. We also calculate the binding energy of the ground state exciton and the confinement energy of the 1D quantum-wire-exciton state with respect to the 2D quantum-well exciton for a wide range of structures, varying the well width and the Al molar fraction $x$. We find that the largest binding energy of any wire constructed to date is 16.5 meV. We also notice that in asymmetric structures, the confinement energy is enhanced with respect to the symmetric forms with comparable parameters but the binding energy of the exciton is then lower than in the symmetric structures. For GaAs/Al$_{x}$Ga$_{1-x}$As wires we obtain an upper limit for the binding energy of around 25 meV in a 10 {\AA} wide GaAs/AlAs structure which suggests that other materials must be explored in order to achieve room temperature applications. There are some indications that In$_{y}$Ga$_{1-y}$As/Al$_{x}$Ga$_{1-x}$As might be a good candidate.Comment: 20 pages, 10 figures, uses RevTeX and psfig, submitted to Physical Review

SDG 3: Good health and well-being - framing targets to maximise co-benefits for forests and people

Key Points: The achievement of SDG 3 depends on many other SDGs; some SDGs are logically inconsistent, especially in the attempt to increase conventionally defined GDP while preserving natural capital. Any short-term gains for human health from further forest conversion (e.g. food production) creates short- and long-term, direct and indirect health risks for humans, as well as for other biota. Failure to ensure universal access to sexual and reproductive healthcare services (including family planning) will increase pressure on forests at local, regional and global scales. The burning and clearing of forests cause significant harm to health via impaired quality of water, soil and air; increased exposure to infectious diseases and impacts climate regulation. Many infectious diseases are associated with forest disturbances and intrusions; some important infectious diseases have emerged from forests (notably HIV/AIDS). Greater exposure to green space, including forests, provides mental and physical health benefits for the growing global urban population

Statin treatment and risk of recurrent venous thromboembolism: a nationwide cohort study

Statins may decrease the risk of primary venous thromboembolism (VTE), that is, deep vein thrombosis (DVT) and pulmonary embolism (PE) but the effect of statins in preventing recurrent VTE is less clear. The aim of this study was therefore to investigate the association between statin therapy and risk of recurrent VTE. A prospective cohort study. All hospitals in Denmark. All patients with a hospital diagnosis of VTE in Denmark during 1997-2009 associated with a warfarin or heparin prescription were identified. Adjusted HR of recurrent hospitalised VTE (ie, fatal or non-fatal DVT or PE) associated with use of statins. 44 330 patients with VTE were included in the study. Of these 3914 were receiving statin therapy at baseline. Patients receiving statins were older (68±11 compared to 62±18 years), had more comorbidity and used more medications. The incidence rate for recurrent VTE was 24.4 (95% CI 22.8 to 26.2) per 1000 person-years among statin users and 48.5 (95% CI 47.4 to 49.7) per 1000 person-years among non-statin users. Statin use was associated with a significantly lower risk of a recurrent VTE, adjusted HR 0.74 (95% CI 0.68 to 0.80), compared with no statin use. The association between statin use and risk of recurrent VTE was significantly affected by age. Among younger individuals (≤80 years), statin use was associated with lower risk of recurrent VTE, HR 0.70 (95% CI 0.65 to 0.76) whereas in older individuals (>80 years) statin use was significantly associated with higher risk of recurrent VTE, HR 1.28 (95% CI 1.02 to 1.60), p for interaction= <0.0001. Statin use was associated with a decreased risk of recurrent VT

Does macrolide use confer risk of out-of-hospital cardiac arrest compared with penicillin V? A Danish national case-crossover and case–time–control study

Introduction and objectivesMacrolides have been associated with proarrhythmic properties, but the evidence is conflicting. We evaluated the risk of out-of-hospital cardiac arrest (OHCA) associated with specific macrolides in a retrospective study. Associations between specific macrolides and OHCA were examined by conditional logistic regression analyses in case-crossover and case–time–control models, using penicillin-V treatment as the comparative reference. From nationwide registries, we identified all OHCAs in Denmark from 2001 to 2010 and use of antibiotics.EthicsThe present study was approved by the Danish Data Protection Agency (Danish Data Protection Agency (ref.no. 2007-58-0015, local ref.no. GEH-2014-017, (I-Suite.nr. 02 735)).ParticipantsWe identified 29 111 patients with an OHCA. Of these, 514 were in macrolide treatment ≤7 days before OHCA and 1237 in penicillin-V treatment.ResultsIn the case-crossover analyses, overall macrolide use was not associated with OHCA with penicillin V as negative comparative reference (OR=0.90; 95% CI 0.73 to 1.10). Compared with penicillin-V treatment, specific macrolides were not associated with increased risk of OHCA: roxithromycin (OR=0.97; 95% CI 0.74 to 1.26), erythromycin (OR=0.68; 95% CI 0.44 to 1.06), clarithromycin (OR=0.95; 95% CI 0.61 to 1.48) and azithromycin (OR=0.85; 95% CI 0.57 to 1.27).Similar results were obtained using case–time–control models: overall macrolide use (OR=0.81; 95% CI 0.62 to 1.06) and specific macrolides (roxithromycin(OR=0.70; 95% CI 0.49 to 1.00), erythromycin(OR=0.67; 95% CI 0.38 to 1.18), clarithromycin(OR=0.75; 95% CI 0.41 to 1.39) or azithromycin(OR=1.17; 95% CI 0.70 to 1.95)).ConclusionThe risk of OHCA during treatment with macrolides was similar to that of penicillin V, suggesting no additional risk of OHCA associated with macrolides.</jats:sec