Free-living inferential modeling of blood glucose level using only noninvasive inputs

The goal of this work is to present a causation modeling methodology with the ability to accurately infer blood glucose levels using a large set of highly correlated noninvasive input variables over an extended period of time. These models can provide insight to improve glucose monitoring, and glucose regulation through advanced model-based control technologies. The efficacy of this approach is demonstrated using real data from a type 2 diabetic (T2D) subject collected under free-living conditions over a period of 25 consecutive days. The model was identified and tested using eleven variables that included three food variables as well as several activity and stress variables. The model was trained using 20 days of data and validated using 5 days of data. This gave a fitted correlation coefficient of 0.70 and an average absolute error (AAE) (i.e., the average of the absolute values for the measured glucose concentration minus modeled glucose concentration) of 13.3 mg/dL for the validation data. This AAE result was significantly better than the subject’s personal glucose meter AAE of 15.3 mg/dL for replicated measurements.     

Curvature-Driven PDE Methods for Matrix-Valued Images

Matrix-valued data sets arise in a number of applications including diffusion tensor magnetic resonance imaging (DT-MRI) and physical measurements of anisotropic behaviour. Consequently, there arises the need to filter and segment such tensor fields. In order to detect edge-like structures in tensor fields, we first generalise Di Zenzo’s concept of a structure tensor for vector-valued images to tensor-valued data. This structure tensor allows us to extend scalar-valued mean curvature motion and self-snakes to the tensor setting. We present both two-dimensional and three-dimensional formulations, and we prove that these filters maintain positive semidefiniteness if the initial matrix data are positive semidefinite. We give an interpretation of tensorial mean curvature motion as a process for which the corresponding curve evolution of each generalised level line is the gradient descent of its total length. Moreover, we propose a geodesic active contour model for segmenting tensor fields and interpret it as a minimiser of a suitable energy functional with a metric induced by the tensor image. Since tensorial active contours incorporate information from all channels, they give a contour representation that is highly robust under noise. Experiments on three-dimensional DT-MRI data and an indefinite tensor field from fluid dynamics show that the proposed methods inherit the essential properties of their scalar-valued counterparts.     

Validity of the children and youth physical self-perception profile: a confirmatory factor analysis

MOTIVATION: The Match-Box software comprises protein sequence alignment tools based on strict statistical thresholds of similarity between protein segments. The method circumvents the gap penalty requirement: gaps being the result of the alignment and not a governing parameter of the procedure. The reliable conserved regions outlined by Match-Box are particularly relevant for homology modelling of protein structures, prediction of essential residues for site-directed mutagenesis and oligonucleotide design for cloning homologous genes by polymerase chain reaction (PCR). RESULTS: The method produces reliable results, as assessed by tests performed on protein families of known structures and of low sequence similarity. A reliability score is computed in relation to a threshold of similarity progressively raised to extend the aligned regions to their maximal length, up to the significance limit of matching segments. The score obtained at each position is printed below the sequences and allows a discriminant reading of each aligned region. AVAILABILITY: Sequences may be submitted to a Web server at http://www.fundp.ac.be/sciences/biologie/bms/+ ++matchbox_submit.html or sent by e-mail to matchbox/biq.fundp.ac.be (help available by just mailing help).     

Morphological and phase dependence of nanotitania materials generated under extreme pH conditions for large scale production of TiO<Subscript>2</Subscript> nanowires (basic) and nanosquares or nanrods (acidic)

The effect that the phase of the starting nanoseed titania (TiO₂), the pH of the solvent solution, and the processing methodology employed have on the properties of the resultant TiO₂ nanomaterials were explored. This led to the development of a new process to produce large-scale, phase pure, thin nanowires of TiO₂ at high pH and nanosquares at low pH. Anatase, rutile, and Degussa P25^TM TiO₂ nanoparticle starting materials (or nanoseeds) were processed in strongly basic (10 M KOH) and strongly acidic (conc. HX, where X = Cl, Br, I) solutions using solvothermal (SOLVO) and solution precipitation (SPPT) methodologies. Under basic SOLVO conditions, the nanoseeds were converted to H₂Ti₂O₅·H₂O nanowires. The SPPT basic conditions also produced the same phased nanowires for the rutile and anatase nanoseeds, while the Degussa nanomaterial yielded mixed phased [anatase:rutile (9:1)] nanowires. The SPPT method was found to produce substantially thinner nanowires in comparison to the SOLVO route, with comparable surface areas but the strong basic media led to etching of the glassware yielding HK₃Ti₄O₄(SiO₄)₃·4H₂O nanorods. Hybridization of these two processing routes led to the use of Nalgene^TM bottle as the reaction flask termed the hybrid (HYBR) route, yielding even thinner H₂Ti₂O₅·H₂O nanowires on a large-scale. Switching to a concentrated halide acid (HX, where X = Cl, Br, I) system, SOLVO, SPPT, and HYBR routes were investigated. The resultant TEM images revealed that the rutile starting material yielded short rods, whereas the anatase seeds formed square or faceted materials.     

Neural Networks Relating Alloy Composition, Microstructure, and Tensile Properties of α/β-Processed TIMETAL 6-4

Bayesian neural networks have been developed, which relate composition, microstructure, and tensile properties of the alloy TIMETAL 6-4 (nominal composition: Ti-6Al-4V (wt pct) after thermomechanical processing (TMP) in the two-phase (α + β)-phase field. The developed networks are able to make interpolative predictions of properties within the ranges of composition and microstructural features that are in the population of the database used for training and testing of the networks. In addition, the neural networks have been used to conduct virtual experiments which permit the functional dependencies of properties on composition and microstructural features to be determined. In this way, it is shown that in the microstructural condition resulting from TMP in the two-phase (α + β) phase field, the most significant contribution to strength is from solid solution strengthening, with microstructural features apparently influencing the balance of a number of properties.     

Morphological Amoebas Are Self-snakes

This paper is concerned with amoeba median filtering, a structure-adaptive morphological image filter. It has been introduced by Lerallut et al. in a discrete formulation. Experimental evidence shows that iterated amoeba median filtering leads to segmentation-like results that are similar to those obtained by self-snakes, an image filter based on a partial differential equation. We establish this correspondence by analysing a space-continuous formulation of iterated amoeba median filtering. We prove that in the limit of vanishing radius of the structuring elements, iterated amoeba median filtering indeed approximates the partial differential equation of self-snakes. This result holds true under very general assumptions on the metric used to construct the amoebas. We present experiments with discrete iterated amoeba median filtering that confirm qualitative and quantitative predictions of our analysis.     

Image Compression with Anisotropic Diffusion

Compression is an important field of digital image processing where well-engineered methods with high performance exist. Partial differential equations (PDEs), however, have not much been explored in this context so far. In our paper we introduce a novel framework for image compression that makes use of the interpolation qualities of edge-enhancing diffusion. Although this anisotropic diffusion equation with a diffusion tensor was originally proposed for image denoising, we show that it outperforms many other PDEs when sparse scattered data must be interpolated. To exploit this property for image compression, we consider an adaptive triangulation method for removing less significant pixels from the image. The remaining points serve as scattered interpolation data for the diffusion process. They can be coded in a compact way that reflects the B-tree structure of the triangulation. We supplement the coding step with a number of amendments such as error threshold adaptation, diffusion-based point selection, and specific quantisation strategies. Our experiments illustrate the usefulness of each of these modifications. They demonstrate that for high compression rates, our PDE-based approach does not only give far better results than the widely-used JPEG standard, but can even come close to the quality of the highly optimised JPEG2000 codec.     

The validity of the Tritrac-R3D activity monitor for the assessment of physical activity: II. Temporal relationships among objective assessments

Today the organ donor operation in brain dead donors is mostly projected as multiple organ procurement (MOP). Not only the kidneys, but heart and liver or additionally lungs and pancreas are removed in MOP. A good synchronization between the collaborating transplantation groups (thoracic and abdominal surgeon, urologist) is essential to prevent loss of an organ because of technical problems. In Germany urologists perform more than 40% of kidney transplantations. These urologic institutions perform the cadaver kidney retrievals and participate on MOP. If possible, an urologist experienced in renal transplantation should contribute to the care for quality of the kidneys. Since 1987 the transplant center of Bremen obtained 390 donor registrations. 202 organ donor operations have been performed (106 MOP and 96 exclusive kidney retrievals). 398 donor kidneys have been collected and 382 could be transplanted.