Detection of macroenzymes: establishing upper reference limits for eight enzymes after polyethylene glycol precipitation

IntroductionThe presence of macroenzymes in blood can cause diagnostic confusion. Therefore, confirming the presence of macroenzymes is important to reduce unnecessary (non-)invasive investigations. Polyethylene glycol (PEG) precipitation is a simple and fast first-line method for the detection of macroenzymes. However, there is no consensus on the upper reference limit for the PEG-precipitable activity (%PPA) of monomeric enzymes. The aim of this study was to verify a PEG precipitation protocol for the detection of macroenzymes in our laboratory by establishing upper reference limits (URLs) and determining imprecision for eight enzymes after PEG precipitation. In addition, we aimed to clinically verify the URLs using samples containing macroenzymes as identified by electrophoresis. Materials and methodsPer enzyme, at least 40 leftover blood samples from adult patients with either normal or increased enzyme activities were diluted 1:1 with 25% PEG 6000 and 1:1 with 0.9% NaCl. Mixtures were incubated for 10 min at 37°C and centrifuged. Supernatant enzyme activity was measured on Cobas c702 and the %PPA was calculated. ResultsThe following URLs were obtained: 26% PPA for amylase, 29% PPA for alkaline phosphatase (ALP), 61% PPA for alanine aminotransferase, 48% PPA for aspartate aminotransferase, 24% PPA for creatine kinase (CK), 55% PPA for gamma-glutamyltransferase, 65% PPA for lactate dehydrogenase, and 56% PPA for lipase. The within-lab imprecision was < 15%. Regarding the clinical verification, the two historical samples with proven macroCK showed a %PPA of 69% and 43%, respectively, and a sample with proven macroALP had a %PPA of 52%. ConclusionIn this study, URLs for monomeric enzyme activities after PEG precipitation for eight different enzymes were established. The URLs are suitable for clinical use, but are only partially in line with other studies. Therefore, our data highlight the importance of establishing laboratory-specific upper reference limits for %PPA to allow a correct interpretation

Effects due to overlapping large impact basins on Mars

Many ancient, highly degraded large impact basins exist on Mars. In many cases these basins overlap or are overlapped by more easily observed, presumably younger, impact basins. While impact basin overlap is becoming more recognized, the effects of such overlap have only occassionally been described. Such effects will depend on a variety of factors including the absolute and relative size of the basins, the degree of overlap, the state of the lithosphere and its thermal gradient at the time of impact, and the time between impacts. There now exists enough evidence for overlapping basins of different sizes that some of these can be discussed. This paper highlights some examples of the obvious effects of basin overlap

Retrospective case control study of pet ferrets with cystine urolithiasis in Quebec, Canada : epidemiological and clinical features

Objective: To describe epidemiological and clinical features of cystine urolithiasis in pet ferrets. Methods: Retrospective case control study on medical records from four private clinics and one teaching hospital for pet ferrets diagnosed with cystine urolithiasis confirmed by spectrophotometry presented between July 2014 and July 2019 in Quebec, Canada; these cases were then compared to a reference population of 210 ferrets (controls) presented at the same facilities over the same timeframe. Results: Among the 36 identified cases, most affected ferrets were neutered males (32/36, 89%) and the mean age at presentation was 1.8 (± 1.0 standard deviation) year. Grain-free diets of six different brands were offered for at least three weeks prior to the presentation to 34/36 (94%) of the included cases. The ferrets that developed cystine urolithiasis were 57.9 times (Odds ratio [OR], 95% Confidence interval [95% CI]: 11.0, 304.8) more likely to receive a grain-free diet compared to the reference population. No significant difference in the values for the energy, protein, cysteine, and methionine contents were detected between the grainfree and the cereal-based diets offered to these pet ferrets. Among ferrets with uroliths, those with urethral calculi were 4.7 times (OR, 95% CI: 2.1, 10.4) more likely to develop an acute urinary tract obstruction. Conclusion: Although a definitive causation could not be drawn solely from these clinical cases, this case control study highlights a possible nutritional aetiology in the complex pathogenesis of cystine urolithiasis in ferrets

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Design status of ASPIICS, an externally occulted coronagraph for PROBA-3

The "sonic region" of the Sun corona remains extremely difficult to observe with spatial resolution and sensitivity sufficient to understand the fine scale phenomena that govern the quiescent solar corona, as well as phenomena that lead to coronal mass ejections (CMEs), which influence space weather. Improvement on this front requires eclipse-like conditions over long observation times. The space-borne coronagraphs flown so far provided a continuous coverage of the external parts of the corona but their over-occulting system did not permit to analyse the part of the white-light corona where the main coronal mass is concentrated. The proposed PROBA-3 Coronagraph System, also known as ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), with its novel design, will be the first space coronagraph to cover the range of radial distances between ~1.08 and 3 solar radii where the magnetic field plays a crucial role in the coronal dynamics, thus providing continuous observational conditions very close to those during a total solar eclipse. PROBA-3 is first a mission devoted to the in-orbit demonstration of precise formation flying techniques and technologies for future European missions, which will fly ASPIICS as primary payload. The instrument is distributed over two satellites flying in formation (approx. 150m apart) to form a giant coronagraph capable of producing a nearly perfect eclipse allowing observing the sun corona closer to the rim than ever before. The coronagraph instrument is developed by a large European consortium including about 20 partners from 7 countries under the auspices of the European Space Agency. This paper is reviewing the recent improvements and design updates of the ASPIICS instrument as it is stepping into the detailed design phase

Design and modelisation of a straylight facility for space optical instrument

In the framework of instrument calibration, straylight issues are a critical aspect that can deteriorate the optical performances of instrument. To cope with this, a new facility is designed dedicated for in-field and far field straylight characterization: up to 10-8 for in-field and up to 10-10 for far field straylight in the visible to NIR spectral ranges. Moreover, from previous straylight test performed at CSL, vacuum conditions are needed for reaching the 10-10 rejection requirement mainly to avoid air/dust diffusion. The major constrains are to design a straylight facility either for in-field and out-field straylight measurements. That requires high dynamic range at source level and a high radiance point source allowing small diverging collimated beam. Moreover, the straylight facility has to be implemented into a limited envelope and has to be built with vacuum compatible materials and black coating. As checking the facility performance requires an instrument better than the facility itself, that is no easy to find, so that the performances have been estimated through a modelisation into a non sequential optical software. This modelisation is based on CAD importation of mechanical design, on BRDF characteristics of black coating and on statistical averaging of ray tracing at instrument entrance.PROBA

A Survey on Common Practice in Designing Audio in the User Interface

The current practice of designing the auditory mode in the user interface is poorly understood. In this survey, we aim at revealing the common understanding of the role of audio in human-computer interaction and how designers approach design tasks involving audio. We investigate which guidelines and principles participants use in their designs and which guidance is needed to improve the quality of auditory design. The responses are analysed and interpreted by quantitative and qualitative methods. The 86 participants enabled us to draw a relatively accurate picture of how the field is perceived and helped to identify problems in the design of efficient audio in the user interface. The results of the survey are subsequently developed into requirements for a methodological design framework, with the aim to provide easily accessible guidance for designers to integrate audio in the user interface. Categories and Subject Descriptors H.5.2 [Information Interfaces and Presentation (e.g., HCI)]