The hip radiographic magnification correlates with patient’s BMI

Objective. Obese patients have a higher prevalence of total hip arthroplasty (THA) and they are likely to experience a higher rate of pre-operative and post-operative complications. Pre-operative templating is a standard method of THA planning aiming to minimize the risk of complications. The accuracy of pre-operative templating depends on the knowledge of radiographic magnification factor. Whether and to what extent obesity affects radiographic magnification is not well described in literature. The purpose of this study was to determine whether obesity type affects hip radiographic magnification and quantify the relationship between the obesity measured and change in radiographic magnification. Materials and Methods. Digital radiographs of 303 patients who underwent THA were taken from clinical archives. The size of implanted femoral head was taken as an internal calibration marker to estimate hip radiographic magnification. Patients were stratified into obesity categories by body mass index (BMI). Patients’ mass, BMI, and body surface area (BSA) were studied as predictors of hip magnification. Results. There is a significant effect of obesity type on hip radiographic magnification (one-way ANOVA, p<0.001). The radiographic magnification correlates with patients’ mass (r=0.443, p<0.001), BMI (r=0.450, p<0.001) and BSA (r=0.443, p<0.001). For every 17 kg increase in patients’ mass, 5 kg/m2 increase in the BMI and for every 0.27 m2 in the BSA there is a 1 percent increase in the hip radiographic magnification. The increase in hip radiographic magnification with mass, BMI, and BSA is higher in females than in males. Conclusion. BMI could be used to estimate the increase in hip radiographic magnification due to obesity by adding 1% of magnification on average for each subsequent BMI category.

Melting Curve Analysis of Aptachains: Adenosine Detection with Internal Calibration

Small molecules are ubiquitous in nature and their detection is relevant in various domains. However, due to their size, sensitive and selective probes are difficult to select and the detection methods are generally indirect. In this study, we introduced the use of melting curve analysis of aptachains based on split-aptamers for the detection of adenosine. Aptamers, short oligonucleotides, are known to be particularly efficient probes compared to antibodies thanks to their advantageous probe/target size ratio. Aptachains are formed from dimers with dangling ends followed by the split-aptamer binding triggered by the presence of the target. The high melting temperature of the dimers served as a calibration for the detection/quantification of the target based on the height and/or temperature shift of the aptachain melting peak.

an agile high-frequency radar used for ionospheric research

The Super Dual Radar Network (SuperDARN) is an international high-frequency (HF) radar network used to study plasma convection in the upper atmosphere. An agile SuperDARN radar (AgileDARN radar) was deployed to join the network in Jiamusi, China. The AgileDARN radar is a digital phased array radar equipped with an FPGA-based digital processing unit (DPU). It can operate as a standard SuperDARN radar or a multiple-input-multiple-out (MIMO) radar. Each channel can be controlled and processed separately. Digital beam forming (DBF) is used to make beam steering flexible and beam switching fast. Multiple sub-beam forming for receiving can be implemented on FPGA or computer to improve position accuracy. Additionally, internal calibration and external calibration are carried out to improve the performance of beam forming. The internal calibration is a self-calibration without any external connections. Calibration signals are produced by the generators in DPU. The gain and phase of transmitters/receivers are read and compared to the based transmitter/receiver. Then the differences are recorded to compensate for the imbalances. During the external calibration, meteor trails are used as calibration sources to detect the imbalance between antennas (including cables). The imbalances are compensated in the same way as the internal calibration. By calibration, the amplitude and phase imbalances between channels are reduced significantly.

Monitoring the TROPOMI-SWIR module instrument stability using desert sites

Since its launch in 2017, the TROPOMI instrument on S-5P has provided very high quality data using daily global coverage for a number of key atmospheric trace gasses. Over its first 1,000 days in operations, the SWIR module has been very stable and the continuously monitored calibration has remained of high quality. This calibration relies on a combination of extensive pre-launch and post-launch measurements, complemented by regular monitoring of internal light sources and background measurements. In this paper we present a method and results for independent validation of the SWIR module calibration and instrument stability by examining the signal stability of a sample of 23 pseudo-invariant calibration desert sites. The data covers over two years of operational data. With a Lambertian surface assumption, the results show that the SWIR module has little to no instrument degradation down to an accuracy of about 0.3 % per year, validating results obtained from the internal calibration suite. The method presented here will be used as ongoing validation of the SWIR calibration.