Carbon Ion Fluxes at Mars: First Results of Tailward Flows From MAVEN-STATIC.

Characterizing C+ ions in the Martian ionosphere is important for understanding the history of the Martian atmosphere and surface due to its place in understanding carbon escape. Measuring minor ions, like C+, which are close in mass to major atmospheric ions, in this case O+, is difficult, requiring fitting algorithms and accurate background subtraction. Accurate measurement of these species is essential for understanding chemistry and transport in the ionosphere. In this paper, we use data from the Mars Atmospheric and Volatile EvolutioN SupraThermal And Thermal Ion Composition (MAVEN-STATIC) sensor to report the first C+ fluxes measured in the Martian magnetotail. We will describe a multistep method of background subtraction as well as fitting routines that are used to extract C+ fluxes from a 40-orbit subset of STATIC data. Our results show tailward fluxes in both optical shadow and the adjacent sunlit magnetotail at high altitudes ( > 3,000 km) and Mars-ward at low altitudes ( < 2,000 km) in shadow. These local flux values are similar to estimates of neutral carbon fluxes from photochemical escape. However, total carbon loss comparisons will require a more comprehensive study of integrated C+ loss over a larger data set from the Martian magnetotail.

Digital Impedance Emulator for Battery Measurement System Calibration.

Meaningful information on the internal state of a battery can be derived by measuring its impedance. Accordingly, battery management systems based on electrochemical impedance spectroscopy are now recognized as a feasible solutions for online battery control and diagnostic. Since the impedance of a battery is always changing along with its state of charge and aging effects, it is important to have a stable impedance reference in order to calibrate and test a battery management system. In this work we propose a programmable impedance emulator that in principle could be used for the calibration of any battery management system based on electrochemical impedance spectroscopy. A digital finite-impulse-response filter is implemented, whose frequency response is programmed so as to reproduce exactly the impedance of a real battery in the frequency domain. The whole design process of the filter is presented in detail. An analytical expression for the impedance of real battery in the frequency domain is derived from an equivalent circuit model. The model is validated both through numerical simulations and experimental tests. In particular, the filter is implemented on a low-cost microcontroller unit, and the emulated impedance is measured by means of a custom-made electrochemical impedance spectroscopy measuring system, and verified by using standard commercial bench instruments. Results on this prototype show the feasibility of using the proposed emulator as a fully controllable and low-cost reference for calibrating battery impedance measurement systems.

Calibrating analytical ultracentrifuges.

Analytical ultracentrifugation (AUC) is based on the concept of recording and analyzing macroscopic macromolecular redistribution that results from a centrifugal force acting on the mass of suspended macromolecules in solution. Since AUC rests on first principles, it can provide an absolute measurement of macromolecular mass, sedimentation and diffusion coefficients, and many other quantities, provided that the solvent density and viscosity are known, and provided that the instrument is properly calibrated. Unfortunately, a large benchmark study revealed that many instruments exhibit very significant systematic errors. This includes the magnification of the optical detection system used to determine migration distance, the measurement of sedimentation time, and the measurement of the solution temperature governing viscosity. We have previously developed reference materials, tools, and protocols to detect and correct for systematic measurement errors in the AUC by comparison with independently calibrated standards. This 'external calibration' resulted in greatly improved precision and consistency of parameters across laboratories. Here we detail the steps required for calibration of the different data dimensions in the AUC. We demonstrate the calibration of three different instruments with absorbance and interference optical detection, and use measurements of the sedimentation coefficient of NISTmAb monomer as a test of consistency. Whereas the measured uncorrected sedimentation coefficients span a wide range from 6.22 to 6.61 S, proper calibration resulted in a tenfold reduced standard deviation of sedimentation coefficients. The calibrated relative standard deviation and mean error of 0.2% and 0.07%, respectively, is comparable with statistical errors and side-by-side repeatability in a single instrument.

Common problems and solutions in hospital point-of-care testing quality management / 中华检验医学杂志

The rapid development of point-of-care testing (POCT) in clinical laboratories has brought challenges to the unified management in the hospital. There are many problems, such as how to ensure the ability and qualification of POCT operators, how to improve the quality management awareness of human, machines, materials, methods and environment in the process of POCT in clinical laboratories, how to help the clinical laboratories in the hospital to carry out POCT comparison, and how to strengthen the information construction of POCT in the hospital. Thus, this article reviews the practice and experience of POCT management in our hospital on POCT quality assurance and the problems existing in POCT in clinical departments, proposes suggestions and solutions to strengthen the unified management of POCT in clinical laboratories and establish POCT quality management documents and to improve quality awareness. We hope to provide references for hospital administrators, medical departments, nursing departments, quality control departments and other functional departments on the quality management of POCT in the hospital, and find helpful answers to the puzzles of clinical laboratory in POCT, so as to make joint efforts to standardize the quality management of POCT in the hospital to ensure the accuracy of testing results.

Quantitative Analysis of Protein Self-Association by Sedimentation Velocity.

Sedimentation velocity analytical ultracentrifugation is a powerful classical method to study protein self-association processes in solution based on the size-dependent macromolecular migration in the centrifugal field. This technique can elucidate the assembly scheme, measure affinities ranging from picomolar to millimolar Kd , and in favorable cases provide information on oligomer lifetimes and hydrodynamic shape. The present step-by-step protocols detail the essential steps of instrument calibration, experimental setup, and data analysis. Using a widely available commercial protein as a model system, the protocols invite replication and comparison with our results. A commentary discusses principles for modifications in the protocols that may be necessary to optimize application of sedimentation velocity analysis to other self-associating proteins. ©2020 Wiley Periodicals LLC. Basic Protocol 1: Measurement of external calibration factors Basic Protocol 2: Sedimentation velocity experiment for protein self-association Basic Protocol 3: Sedimentation coefficient distribution analysis in SEDFIT and isotherm analysis in SEDPHAT.

Optimizing the Calibration Error of Refraction Angles in Ultrasonic Angle Beam Testing.

Ultrasonic testing is a useful approach for quantifying the flaws in mechanical components. The height of the flaws in ultrasonic angle beam testing is closely related to the calibration value of the probe refraction angle. In order to reduce the calibration error, some ignored data during the traditional calibration process are reanalyzed and fused to determine the refraction angle. Both arithmetical measurement fusion method and weighted measurement fusion method are applied and compared. Monte Carlo simulation is used to estimate the probability distribution of the refraction angle and obtain the optimal refraction angle weights. Experiments were carried out to verify the results of Monte Carlo simulation. The applicability of data fusion on refraction angles is investigated. It was found in the study that the data fused with the refraction angle is helpful for measuring the height of flaws.

Establishing a common metric for self-reported pain: linking BPI Pain Interference and SF-36 Bodily Pain Subscale scores to the PROMIS Pain Interference metric.

PURPOSE: The study purposes were to mathematically link scores of the Brief Pain Inventory Pain Interference Subscale and the Short Form-36 Bodily Pain Subscale (legacy pain interference measures) to the NIH Patient-Reported Outcome Measurement Information System (PROMIS(®)) Pain Interference (PROMIS-PI) metric and evaluate results. METHODS: Linking was accomplished using both equipercentile and item response theory (IRT) methods. Item parameters for legacy items were estimated on the PROMIS-PI metric to allow for pattern scoring. Crosswalk tables also were developed that associated raw scores (summed or average) on legacy measures to PROMIS-PI scores. For each linking strategy, participants' actual PROMIS-PI scores were compared to those predicted based on their legacy scores. To assess the impact of different sample sizes, we conducted random resampling with replacement across 10,000 replications with sample sizes of n = 25, 50, and 75. RESULTS: Analyses supported the assumption that all three scales were measuring similar constructs. IRT methods produced marginally better results than equipercentile linking. Accuracy of the links was substantially affected by sample size. CONCLUSIONS: The linking tools (crosswalks and item parameter estimates) developed in this study are robust methods for estimating the PROMIS-PI scores of samples based on legacy measures. We recommend using pattern scoring for users who have the necessary software and score crosswalks for those who do not.

Early catastrophic failure of trochanteric fixation with the Dall-Miles Cable Grip System.

Multi-filament orthopaedic cerclage cables have been used in clinical practice for several decades, and are commonly utilized to provide greater trochanteric fixation following an osteotomy or fracture. We present the first known report of patients who experienced early catastrophic failure following use of the Dall-Miles Cable Grip System (DMCGS). A root cause analysis determined that the jaws of one crimper had an increased distance at closure, resulting in inadequate ultimate fixation strength. It was discovered that operating room staff had not been trained to perform regular calibration checks and the required calibration tool was not included in any of the institution's DMCGS sets. Surgeons should be aware that these surgical instruments require regular maintenance and should be gauge tested prior to every use.

Complete elliptical ring geometry provides energy and instrument calibration for synchrotron-based two-dimensional X-ray diffraction.

A complete calibration method to characterize a static planar two-dimensional detector for use in X-ray diffraction at an arbitrary wavelength is described. This method is based upon geometry describing the point of intersection between a cone's axis and its elliptical conic section. This point of intersection is neither the ellipse centre nor one of the ellipse focal points, but some other point which lies in between. The presented solution is closed form, algebraic and non-iterative in its application, and gives values for the X-ray beam energy, the sample-to-detector distance, the location of the beam centre on the detector surface and the detector tilt relative to the incident beam. Previous techniques have tended to require prior knowledge of either the X-ray beam energy or the sample-to-detector distance, whilst other techniques have been iterative. The new calibration procedure is performed by collecting diffraction data, in the form of diffraction rings from a powder standard, at known displacements of the detector along the beam path.

Calibración del índice de Hiperactividad de Conners mediante el modelo de Rasch / Calibration of Conners ADHD Index with Rasch Model

El objetivo del presente estudio se ha centrado en la calibración de la versión española de la escala reducida de 10 ítems (Indice de Hiperactividad de Conners [IHC]) mediante el modelo de Rasch, utilizando una muestra de 482 niños de 5 y 6 años. Los resultados mostraron que el IHC tiene buenas propiedades psicométricas. El ajuste, tanto de los ítems como de las personas al modelo de Rasch, es bueno y las categorías de respuesta funcionan adecuadamente. Las puntuaciones de los niños fueron significativamente superiores a las de las niñas. Tres de los ítems tienen riesgo de presentar Funcionamiento Diferencial del Ítem (DIF) en función del género. El IHC tiene un evidente efecto suelo que impide evaluar a niños con niveles de hiperactividad bajos.

Conners Hyperactivity Index or Conners 3-AI using the Rasch model. The participants in this study were 482 children aged 5 and 6 years old. Results showed that the IHC has good psychometric properties. The fit of both items and persons data to Rasch model was good, and the response categories were functioning properly. Boys scored significantly higher than girls. Three of the items were at risk of gender-specific DIF. The Conners 3-AI has an obvious floor effect, which prevents the evaluation of children with low levels of hyperactivity.