The authors describe the deposition of single biomolecules on substrates at defined spacing by pure self-assembly. The substrate is equipped with an array of 8 nm large gold particles which form the ...template for biomolecule binding. The authors verified the successful binding of single biomolecules via specific antibody labeling and imaging by fluorescence microscopy. Scanning force microscopy provided evidence that every gold nanoparticle of the pattern is occupied by at least one biomolecule. Furthermore, gold conjugated secondary antibodies in combination with scanning electron microscopy proved that at least 75% of the nanoparticles carried only one active biomolecule. The precision given by such surface densities is molecularly defined and such considerably higher than in any other case reported so far.
ObjectiveObstructive sleep apnoea (OSA) is a risk factor for vascular disease and other adverse outcomes. These associations may be at least partly due to early endothelin-1 (ET-1)-mediated ...endothelial dysfunction (ED). Therefore, we assessed the relationships between subclinical sleep apnoea and plasma levels of ET-1.MethodsWe performed a population-based study among 1255 young and healthy adults aged 25–41 years. Cardiovascular disease, diabetes or a body mass index >35 kg/m2 were exclusion criteria. Plasma levels of ET-1 were measured using a high-sensitivity, single-molecule counting technology. The relationships between subclinical sleep apnoea (OSA indices: respiratory event index (REI), oxygen desaturation index (ODI), mean night-time blood oxygen saturation (SpO2)) and ET-1 levels were assessed by multivariable linear regression analysis.ResultsMedian age of the cohort was 35 years. Median ET-1 levels were 2.9 (IQR 2.4–3.6) and 2.5 pg/mL (IQR 2.1–3.0) among patients with (n=105; 8%) and without subclinical sleep apnoea (REI 5–14), respectively. After multivariable adjustment, subclinical sleep apnoea remained significantly associated with plasma levels of ET-1 (β=0.13 (95% CI 0.06 to 0.20) p=0.0002 for a REI 5–14; β=0.10 (95% CI 0.03 to 0.16) p=0.003 for an ODI≥5). Every 1% decrease in mean night-time SpO2 increased ET-1 levels by 0.1 pg/mL, an association that remained significant after multivariable adjustment (β=0.02 (95% CI 0.003 to 0.033) p=0.02).ConclusionsIn this study of young and healthy adults, we found that participants with subclinical sleep apnoea had elevated plasma ET-1 levels, an association that was due to night-time hypoxaemia. Our results suggest that ED may already be an important consequence of subclinical sleep apnoea.
The application of video encoding for the compression of Computed Tomography (CT) based projection images is very promising with respect to a more efficient transmission and storage of this ...particular type of data. Especially the use of "off-the-shelf" technologies, such as the H.264/AVC codec, ensures long term support due to its widespread use in the media industry. We present an approach for the application of this standard 8-bit video codec even for 16-bit projection data sets. Based on a benchmark set of 200 pistons, we evaluate its performance in terms of the compression rate relative to the original input data. Furthermore, we compare the detection rate of manufacturing defects in the reconstructed volumes to the state-of-the-art technique without video encoding. For this purpose our benchmark does not only contain the projections of the 200 pistons, but additionally the exact information about location and size of the manufacturing defects of the respective piston. We show that the detection rate based on the video encoded projection data is, up to a certain threshold, as good as without compression.
3-D scanning of sea freight containers using MeV X-rays Firsching, Markus; Bohnel, Michael; Errmann, Gerald ...
2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC),
10/2013
Conference Proceeding
The ECSIT project analyses how innovative inspection technologies can lead to an enhanced container security and how these technologies can be embedded into a holistic concept. It has the goal to ...analyze the possibility and feasibility for 100% scanning of all containers which are shipped to US ports and to develop a concept for integrating necessary infrastructure. A key element of the entire concept is the scanning technology itself. MeV X-ray technology using a linear accelerator as radiation source provides the feasibility to visualize the content of a container without opening it. If a 2-D radiography is ambiguous, a 3-D evaluation of the respective location could be conducted. MeV X-ray computed tomography (CT) is such a method to provide 3-D information of the content of a container. In the context of ECSIT, Fraunhofer EZRT has developed the concept of such a continuative high energy X-ray scanning stage and evaluated its application to sea freight containers. In this paper different approaches for measuring a 3-D tomographic volume data set of objects which are very heavy and thus difficult to move in arbitrary directions will be discussed. Three different geometrical principles for data acquisition were evaluated: laminography, limited angle CT, and a gantry CT. The volume data sets were reconstructed by using a standard filtered back projection and different algebraic reconstruction techniques (ART). Real 3-D volume data of large objects measured with the set-up described above are presented. As test objects a real container packed with various typical goods like furniture or consumer electronics as well as simulated threats like a bomb mock-up was used.
AimsA healthy lifestyle is associated with a lower risk of cardiovascular events and mortality, but underlying mechanisms are not fully understood. The aim of our study was to investigate the ...relationships between a healthy lifestyle and glucagon-like peptide-1 (GLP-1), an incretin hormone with both glycemic and cardiovascular properties.MethodsHealthy participants aged 25-41 years without cardiovascular disease, diabetes or a body mass index (BMI) >35 kg/m were enrolled in a population-based study. The following metrics were used to build a lifestyle score ranging from 0 to 7 (higher score indicating healthier lifestyle)blood pressure (BP) (<120/80 mmHg), plasma levels of glycated haemoglobin (<5.7%), total cholesterol levels (<200 mg/dl), BMI (<25 kg/m), never smoking cigarettes, physical activity (>75 min/week) and a healthy diet.ResultsAmong 2133 participants median age was 36.7 years and 53.3% were female. GLP-1 levels significantly decreased from 43.6 to 28.7 ng/l across increasing lifestyle score categories (p<0.0001). This linear relationship persisted in multivariable adjusted linear regression models (β for GLP-1 per 1-unit increase of the lifestyle score -0.06; 95% confidence intervals -0.07, -0.04; p<0.0001) and across lifestyle score categories (p for trend <0.0001, Figure). Individual health metrics that were significantly associated with GLP-1 were a normal BMI (-0.07; -0.12, -0.03; p=0.0009), low total cholesterol levels (-0.07; -0.12, -0.03; p=0.002), normal BP (-0.05; -0.10, -0.01; p=0.03) and not smoking cigarettes (-0.07; -0.11, -0.03; p=0.002).ConclusionsA healthy lifestyle is strongly associated with GLP-1 levels in young and healthy adults. GLP-1 related mechanisms may therefore be involved in lifestyle related beneficial effects.
When digitizing or investigating historical documents, it is often the case that a document can not be opened, page-turned or touched anymore. Damages such as moisture or fire and aging processes ...disallow browsing through a book. To address these particular cases, our earlier work showed that Micro-CT X-ray scanners are able to image documents written with iron gall ink. A self-made book consisting of ten hand written pages was scanned and investigated without opening or page-turning. However, when analyzing the reconstruction results, we faced the problem of a proper automatic page segmentation and 2-D mapping within the volume in an acceptable time without losing information of the writings. The main problem is that the pages can be arbitrary deformed or squeezed together. In this paper, we present a fully automatic algorithm for the segmentation and extraction of book pages from the original 3-D volume. Our method delivers high quality results for our book model and can be easily adapted to other imaging modalities. We show that it performs well even for an extreme case with low resolution input data and wavy pages. To keep it simple for users, our algorithm works without any need of prior information or user interactions.
Computed Tomography (CT) has been around, especially in the medical field, for more than 20 years. Although, the mathematical foundations for CT were known more than a century ago, technical ...limitations delayed its practical application for more than 70 years. Today, we can build CT systems large enough to scan an entire car, yet, for the processing of the resulting data we are facing a "Big (sensor) Data Problem". We currently do not have suitable methods and tools and cannot handle the large amount of data with conventional state-of-the-art techniques. As industrial CT became more and more prevalent over the last few years, especially due its unique features in the field of non destructive testing, we are proposing and evaluating the use of new methods, work flows and technologies, such as Cloud Computing, in order to provide suitable solutions for handling the steadily growing amount of data and its efficient processing.
In this paper we study tomographic reconstruction methods in the case that prior knowledge about the object is available. In particular, we consider the case that a reference object that is similar ...in shape and orientation is available, which is very common in non-destructive testing applications. We demonstrate that a differential version of existing reconstruction methods can easily be derived which reconstructs only the deviation between test and reference object. Since this difference volume is significantly more sparse, the differential reconstruction can be implemented very efficiently. We also discuss the case where knowledge about the misalignment between test and reference object is available, in which case the efficiency of the differential reconstruction can be improved even further. The resulting algorithm is faster, more accurate, and less sensitive to the choice of the step size parameters and regularization than state of the art reconstruction methods.
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