Evaluation of periprosthetic bone using dual-energy x-ray absorptiometry: precision of the method and effect of operation on bone mineral density

To assess the perioperative bone loss of femur during total hip arthroplasty (THA), periprosthetic bone mineral density (BMD) of the seven regions of interests (Gruen zones) was determined with dual-energy x-ray absorptiometry (DXA) preoperatively in both proximal femurs and postoperatively in the involved side in 53 patients with degenerative hip osteoarthrosis. The mean (standard deviation, SD) precision error (coefficient of variation percent, CV%) in various regions of interest (ROIs) based on two consecutive measurements (n = 16) were 2.3 (0.8)%, 2.5 (1.5)%, and 2.8 (1.6)% for uncemented stems, cemented stems, and control sides, respectively. Furthermore, the mean variability caused by the rotation of femur was 3.5 (1.4)%. The most significant perioperative bone loss (13.5-19.2%) was found in the calcar area (zone 7) after noncemented THA. Zone 4, representing the bone below the prosthesis, also showed BMD decreases. These decreases suggest perioperative bone loss owing to rasping and reaming the calcar and bone canal. However, after cemented THA, highly significant BMD increases were found in all the lateral zones. The calcar area was the only site where significant perioperative bone loss was detected (12.8%). In conclusion, DXA is a precise method for quantifying bone mass and density changes in the follow-up of THA. However, when interpreting the results, the preoperative BMD, differences between the femurs and the effect of operation on bone mass should be taken into account. We suggest that the best reference for BMD follow-up is the periprosthetic BMD of the involved side measured soon after the THA.     

IDS: Thermodynamic–kinetic–empirical tool for modelling of solidification,microstructure and material properties

IDS (InterDendritic Solidification) is a thermodynamic–kinetic–empirical tool for simulation of solidification phenomena of steels including phase transformations from melt down to room temperature. In addition, important thermophysical material properties (enthalpy, thermal conductivity, density, etc.) are calculated. The model has been developed in the Laboratory of Metallurgy, Helsinki University of Technology, Finland, since 1984. IDS includes two main modules, the IDS module and the ADC (Austenite DeComposition) module. IDS module simulates the solidification phenomena from liquid down to 1000 °C and ADC the austenite decomposition down to room temperature. Both modules have their own recommended composition ranges. The IDS module is based on the so-called sharp interface concept. The ADC is mainly statistical based on empirical CCT (Continuous Cooling Transformation) diagrams. IDS tool is also coupled with the thermodynamic programmer's library, called ChemApp, developed by a German company, GTT-Technologies. This coupled package is used to simulate among other things multiphase inclusions during solidification. The present paper summarises the features of the IDS tool including the coupling with the ChemApp library.     

Comparison of multitemporal compositing methods for burnt area detection in Southeast Asian conditions

This study investigated the usability of different multitemporal compositing methods for burnt area detection purposes in the humid tropical conditions of insular Southeast Asia, characterised by persisting cloud cover, varying fire‐induced spectral changes and large amount of small burn scars. Six monthly composites of the Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance images (MOD09) were built using six different algorithms. The performance and usability of the compositing algorithms were evaluated using three criteria: separability between burnt and unburnt areas, homogeneity and average sensor zenith angle. Maximum surface temperature method (band 31, 11.0 µm) produced the most homogeneous composites with preference to close‐to‐nadir observations. However, these composites showed unexpectedly low separability between burnt and unburnt areas, mainly due to low spatial resolution of band 31 (1000 m). Overall, taking into account the performance of the compositing methods and the large amount of small burnt areas in insular Southeast Asia, a minimum NIR (band 2, 0.86 µm) method, combined with pre‐compositing cloud and cloud shadow removal, was seen as the most suitable compositing method for burnt area detection in this region. Its strengths were 250 m spatial resolution in pixel selection and high burnt/unburnt separability combined with reasonably good performance on homogeneity and average sensor zenith angle.     

The Boolean column and column-row matrix decompositions

Matrix decompositions are used for many data mining purposes. One of these purposes is to find a concise but interpretable representation of a given data matrix. Different decomposition formulations have been proposed for this task, many of which assume a certain property of the input data (e.g., nonnegativity) and aim at preserving that property in the decomposition. In this paper we propose new decomposition formulations for binary matrices, namely the Boolean CX and CUR decompositions. They are natural combinations of two previously presented decomposition formulations. We consider also two subproblems of these decompositions and present a rigorous theoretical study of the subproblems. We give algorithms for the decompositions and for the subproblems, and study their performance via extensive experimental evaluation. We show that even simple algorithms can give accurate and intuitive decompositions of real data, thus demonstrating the power and usefulness of the proposed decompositions.     

Learning game for improving forklift drivers’ safety awareness

Cognition, Technology & Work - Forklift drivers in in-house logistics are at a high risk of occupational injuries. This study piloted a video-based learning game for forklift drivers, designed...     

Development of Individual Differences in Reading: Results From Longitudinal Studies in English and Finnish.

The authors examined individual differences in reading development in English and Finnish. English-speaking Canadian children were assessed once per year in Grades 1-5, and Finnish children were assessed twice per year in Grades 1-2. Results from latent growth curve and simplex analyses showed that initial status was generally negatively associated with subsequent growth and that, although stable, individual differences were more likely to significantly decrease than to increase across the measurement points. Growth mixture models identified multiple groups of children whose reading development followed distinct patterns. The results indicate that it is possible for educational systems to significantly reduce individual differences in basic reading skills during early reading development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Printed organic diode backplane for matrix addressing an electrophoretic display

An organic matrix diode backplane for driving an electrophoretic display with an unpatterned front plane electrode is reported. Using thin film diodes instead of transistors as the active components in the pixels enable the backplane to be manufactured using roll-to-roll compatible printing processes. The backplane functionality is demonstrated in an electrophoretic display using 16 copper pixel electrodes, each of which is connected to two printed organic diodes. The printed diodes have sputtered copper cathodes and printed silver anodes. The diodes and pixels are arranged in a lateral 4 by 4 matrix structure with a dielectric layer separating the row and column electrodes. The dielectric, semiconductor and silver layers are all printed using a laboratory-scale rotary gravure press. The display module is finalized by laminating the front plane material onto the backplane.     

Effect of pectinolytic juice production on the extractability and fate of bilberry and black currant anthocyanins

Bilberries (Vaccinium myrtillus L.) and black currants (Ribes nigrum L.), dark blue berries rich in anthocyanins, were processed with an aid of commercial pectinolytic enzyme preparations, and the effect of processing on berry anthocyanins was investigated. The enzyme preparations were dosed based on their polygalacturonase activity from 1 to 100 nkat/g of berry mash. The juice yields were determined by weighing, and anthocyanin analyses were performed with HPLC. The bilberry and black currant juice yields increased significantly in enzyme-aided treatments with comparison to control, even with the lowest (1 nkat/g) polygalacturonase dosage. The anthocyanin yield increased by up to 83% for bilberries and up to 58% for black currants in enzyme-aided treatments as compared to control. The results showed that higher polygalacturonase dosage was needed for black currant to achieve the maximal juice and anthocyanin yields than for bilberries. The stability and the profile of extracted anthocyanins were greatly affected by the glycosidase side activities present in the enzyme preparations, which were able to hydrolyze certain anthocyanins to the corresponding aglycones. In addition, the data indicate that anthocyanidin rutinosides were more easily extracted than those of glucosides, which prevailed over the arabinosides and galactosides. Thus, prior to processing it is important to know the intact anthocyanin structures of the raw material, and the activity profile of the enzyme preparation to obtain optimal anthocyanin extractability and enzyme dosage.     

On the Positive-Negative Partial Set Cover problem

The Positive-Negative Partial Set Cover problem is introduced and its complexity, especially the hardness-of-approximation, is studied. The problem generalizes the Set Cover problem, and it naturally arises in certain data mining applications.