Next-generation reference intervals for pediatric hematology.

Background Interpreting hematology analytes in children is challenging due to the extensive changes in hematopoiesis that accompany physiological development and lead to pronounced sex- and age-specific dynamics. Continuous percentile charts from birth to adulthood allow accurate consideration of these dynamics. However, the ethical and practical challenges unique to pediatric reference intervals have restricted the creation of such percentile charts, and limitations in current approaches to laboratory test result displays restrict their use when guiding clinical decisions. Methods We employed an improved data-driven approach to create percentile charts from laboratory data collected during patient care in 10 German centers (9,576,910 samples from 358,292 patients, 412,905-1,278,987 samples per analyte). We demonstrate visualization of hematology test results using percentile charts and z-scores (www.pedref.org/hematology) and assess the potential of percentiles and z-scores to support diagnosis of different hematological diseases. Results We created percentile charts for hemoglobin, hematocrit, red cell indices, red cell count, red cell distribution width, white cell count and platelet count in girls and boys from birth to 18 years of age. Comparison of pediatricians evaluating complex clinical scenarios using percentile charts versus conventional/tabular representations shows that percentile charts can enhance physician assessment in selected example cases. Age-specific percentiles and z-scores, compared with absolute test results, improve the identification of children with blood count abnormalities and the discrimination between different hematological diseases. Conclusions The provided reference intervals enable precise assessment of pediatric hematology test results. Representation of test results using percentiles and z-scores facilitates their interpretation and demonstrates the potential of digital approaches to improve clinical decision-making.

Evaluation of an Interactive Visualization Tool for the Interpretation of Pediatric Laboratory Test Results.

The physiological age-related development of pediatric laboratory results interferes with pathological derangements, which can complicate the interpretation of test results. Recently proposed continuous reference intervals (RIs) promise to be beneficial, although their clinical use may depend on graphical presentations. To estimate the clinical utility of continuous RIs, we developed and evaluated an interactive visualization tool, and examined the differentiation of hemoglobinopathies that is attainable based on the underlying innovative RI model. The implemented web application allows users to easily enter laboratory test results, and displays various visualizations in conjunction with the corresponding RIs, such as charts and personalized Z-scores. To evaluate the usability of the visualization tool, we conducted concurrent think-aloud sessions with four physicians, who were prompted to solve a set of typical interpretation tasks, and acquired additional information through a questionnaire including the System Usability Scale (SUS). We used 85 de-identified clinical cases for an exemplified assessment of how well model-based interpretations of blood count parameters reproduced previously diagnosed hemoglobinopathies. Usability tests as well as questionnaire responses indicated that the developed tool was well received by the physicians. Results from the think-aloud evaluation revealed only minor problems and the tool reached an average SUS score of 86.9, suggesting good usability. Hemoglobinopathy discrimination depended on the considered subtype, although the overall performance of the novel method rivaled the one of the conventional approach. The interactive visualization of innovative continuous reference intervals demonstrated promising results, which justifies further testing on the path towards clinical routine.

High-mobility ZnO nanorod field-effect transistors by self-alignment and electrolyte-gating.

High mobility, solution-processed field-effect transistors are important building blocks for flexible electronics. Here we demonstrate the alignment of semiconducting, colloidal ZnO nanorods by a simple solvent evaporation technique and achieve high electron mobilities in field-effect transistors at low operating voltages by electrolyte-gating with ionic liquids. The degree of alignment varies with nanorod length, concentration and solvent evaporation rate. We find a strong dependence of electron mobility on the degree of alignment but less on the length of the nanorods. Maximum field-effect mobilities reach up to 9 cm(2) V(-1) s(-1) for optimal alignment. Because of the low process temperature (150 °C), ZnO nanorod thin films are suitable for application on flexible polymer substrates.

Concept of a thin film memory transistor based on ZnO nanoparticles insulated by a ligand shell.

In this work, we report on the synthesis and the electrical properties of ZnO nanoparticles, which differ in their organic shell. The introduction of a 2-ethylhexanoate shell instead of a common acetate shell has an impact on the accessible size of the ZnO nanoparticles and changes the electrical properties of thin films in transistors. While acetate covered ZnO particles behave as a semiconductor with an electron mobility of 0.38 cm(2) V(-1) s(-1), the 2-ethylhexanoate ligand shell inhibits a charge transport resulting in insulating films (with an average ε(r) = 9.4). These films can be reconverted to semiconductive layers by removing the ligand shell with oxygen plasma treatment or they can be used as a solution processed dielectric layer in organic transistors. Its use as dielectric allows low voltage device operation and shows potential application as a charge storage layer as needed in non-volatile memory transistors.

Impact of oxygen plasma treatment on the device performance of zinc oxide nanoparticle-based thin-film transistors.

Thin-films of zinc oxide nanoparticles were investigated by photoluminescence spectroscopy and a broad defect-related yellow-green emission was observed. Oxygen plasma treatment was applied in order to reduce the number of defects, and the emission intensity was quenched to 4% of the initial value. Thin-film transistors that incorporate the nanoparticles as active semiconducting layers show an improved device performance after oxygen plasma treatment. The maximum drain current and the charge carrier mobility increased more than 1 order of magnitude up to a nominal value of 23 cm(2) V(-1) s(-1) and the threshold voltage was lowered.