Optimized signal deduction procedure for the MIEZE spectroscopy technique

A method is reported to determine the phase and amplitude of sinusoidally modulated event rates, binned into four bins per oscillation, based on data generated at the resonant neutron spin-echo spectrometer RESEDA at FRM-II. The presented algorithm relies on a reconstruction of the unknown parameters. It omits a calculation-intensive fitting procedure and avoids contrast reduction due to averaging effects. It allows the current data acquisition bottleneck at RESEDA to be relaxed by a factor of four and thus increases the potential time resolution of the detector by the same factor. The approach is explained in detail and compared with the established fitting procedures of time series having four and 16 time bins per oscillation. In addition the empirical estimates of the errors of the three methods are presented and compared with each other. The reconstruction is shown to be unbiased, asymptotic and efficient for estimating the phase. Reconstructing the contrast increases the error bars by roughly 10% as compared with fitting 16 time-binned oscillations. Finally, the paper gives heuristic, analytical equations to estimate the error for phase and contrast as a function of their initial values and counting statistics.

Image Life Trails Based On Contrast Reduction Models For Face Counter-Spoofing

Natural face images are both content and context-rich, in the sense that they carry significant immersive information via depth cues embedded in the form of self-shadows or a space varying blur. Images of planar face prints, on the other hand, tend to have lower contrast and also suppressed depth cues. In this work, a solution is proposed, to detect planar print spoofing by enhancing self-shadow patterns present in face images. This process is facilitated and siphoned via the application of a non-linear iterative functional map, which is used to produce a contrast reductionist image sequence, termed as an image life trail. Subsequent images in this trail tend to have lower contrast in relation to the previous iteration. Differences taken across this image sequence help in bringing out the self-shadows already present in the original image. On a client specific mode, when the subjects and faces are registered, secondary statistics which capture the prominence of self-shadow information, indicate that planar print-images tend to have highly suppressed self-shadows when compared with natural face images. An elaborate tuning procedure, based on a reduced set of training images was developed to first identify the optimal parameter set and then adapt the feature-vectors so that the error-rates were minimized for a specific dataset. Overall mean error rate for the calibration-set (reduced CASIA dataset) was found to be 0.267% and the error rates for other datasets such OULU-NPU and CASIA-SURF were 0.17% and 0.73% respectively

Whole Three-Dimensional Dosimetry of Carbon Ion Beams with an MRI-Based Nanocomposite Fricke Gel Dosimeter Using Rapid T1 Mapping Method

MRI-based gel dosimeters are attractive systems for the evaluation of complex dose distributions in radiotherapy. In particular, the nanocomposite Fricke gel dosimeter is one among a few dosimeters capable of accurately evaluating the dose distribution of heavy ion beams. In contrast, reduction of the scanning time is a challenging issue for the acquisition of three-dimensional volume data. In this study, we investigated a three-dimensional dose distribution measurement method for heavy ion beams using variable flip angle (VFA), which is expected to significantly reduce the MRI scanning time. Our findings clarified that the whole three-dimensional dose distribution could be evaluated within the conventional imaging time (20 min) and quality of one cross-section.

Estimating time-to-contact when vision is impaired

Often, we have to rely on limited information when judging time-to-contact (TTC), as for example, when driving in foul weather, or in situations where we would need reading glasses but do not have them handy. However, most existing studies on the ability to judge TTC have worked with optimal visual stimuli. In a prediction motion task, we explored to what extent TTC estimation is affected by visual stimulus degradation. A simple computer-simulated object approached the observer at constant speed either with clear or impaired vision. It was occluded after 1 or 1.5 s. The observers extrapolated the object’s motion and pressed a button when they thought the object would have collided with them. We found that dioptric blur and simulated snowfall shortened TTC-estimates. Contrast reduction produced by a virtual semi-transparent mask lengthened TTC estimates, which could be the result of distance overestimation or speed underestimation induced by the lower contrast or the increased luminance of the mask. We additionally explored the potential influence of arousal and valence, although they played a minor role for basic TTC estimation. Our findings suggest that vision impairments have adverse effects on TTC estimation, depending on the specific type of degradation and the changes of the visual environmental cues which they cause.

The size-of-source effect in thermography

In thermometry, the displayed temperature value of an object depends on the size of the object. This behaviour, also known as the size-of-source effect (SSE), might be a major cause of measurement uncertainty in a thermoscene. The SSE is caused by diffraction, scattering, reflection, aberration and digitization in the optoelectronic propagation path. The influence of diffraction and digitization (sampling and pixelization) can be described advantageously with the modulation transfer function MTF. The system MTF of an uncooled camera is determined by the diffraction in the lens (optical MTF) and the averaging of the radiation over the pixel area (pixel MTF). If the system MTF is known, the contrast reduction and, thus, the SSE can be calculated. Especially with very small objects, e.g. hotspots creating an image covering less than 4 pixel × 4 pixel on the focal plane, the displayed temperatures are much too low. When imaging large objects, such as area blackbodies, not only the edge areas are affected, but also the entire image. Finally, the contrast reduction by the MTF is explained by means of a complex scene (Siemens star).

P041 CDKN2B-AS1 (ANRIL) expression is decreased in Inflammatory Bowel Disease epithelia and in Celiac, and its reduction is linked with induced cells proliferation

Background Long non-coding RNAs (lncRNAs) have attenuated expression in several immune-mediated disorders. Using mRNAseq of intestinal biopsies, we identified a widespread dysregulation of 459 lncRNAs in the ileum of treatment-naïve pediatric Crohn Disease (CD) patients. We noted that large fraction of downregulated lncRNAs were correlated with epithelial functions. CDKN2B-AS1 (ANRIL) is one of the top most down-regulated lncRNA in CD, and showed decreased expression in Ulcerative Colitis (UC) colon tissues in recent studies. Methods Transcriptomics data is used to evaluate CDKN2B-AS1 expression in mucosal biopsies datasets and in gut epithelia. siRNA oligonucleotides targeting most CDKN2B-AS1 transcripts using Lipofectamine RNAiMAX is used to modulate CDKN2B-AS1 function, and RT-PCR to evaluate mRNA expression. xCELLigence system with gold microelectrodes in plate base is used to measure the impedance as an indicator for cell index. Results CDKN2B-AS1 is down-regulated in bulk mucosal biopsies obtained from CD ileum [fold change (FC) -8, corrected p=1.6E-5], in UC rectum (FC -9.4, corrected p=3.9E-18), and in celiac duodenum (FC -2.3, corrected p=0.03) in comparison to controls. CDKN2B-AS1 is detected under basal conditions in HT-29 cells. Two sets of CDKN2B-AS1 siRNA oligonucleotides (targeting most transcripts) achieved up to 60% reduction in CDKN2B-AS1 expression in HT-29 cells (p=1E-04) as confirmed by RT-PCR using two sets of primers. CDKN2B-AS1 reduction significantly increased cell index as measured by xCELLigence (doubled the index, p=1.7E-03). mRNAseq of the CDKN2B-AS1 reduced HT-29, showed reduction of the tumor suppressor gene APC in CDKN2B-AS1 siRNA treated cells (FC=-1.75, p=0.04) and of TGFBR2 (FC=-1.75, p=0.04). In contrast, reduction of CDKN2B-AS1 resulted in increase in WNT11 (FC=2.1, p=0.02) and TGFB1 (FC=1.9, p=0.04), and induction of the replication associated topoisomerase TOP1MT (FC=2.7, p=0.001). We confirmed these mRNAseq results using RT-PCR. Finally, mimicking inflammation by treating HT-29 with IL1β and LPS, reduced CDKN2B-AS1 expression (by 70%, p=6.3E-04) and doubled the cell index (p=1.8E-03). Conclusion We detected reduced CDKN2B-AS1 expression in three inflammatory disease affecting the gut in different location along the GI tract. Using HT-29 model system we were able to show, as was previously shown, an increase in cell index in CDKN2B-AS1 siRNA treated cells. We supplement those showing effect on down-stream genes that may be relevant in controlling cell proliferation. We further show that upon inflammatory triggering of HT-29 cells, CDKN2B-AS1 expression is reduced and cell index is increased, which may suggest a potential role in epithelial renewal in inflammation.