Melanopic stimulation does not alter psychophysical threshold sensitivity for luminance flicker

In addition to the rod and cone photoreceptors the retina contains intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells express the photopigment melanopsin and are known to be involved in reflexive visual functions such as pupil response and photo-entrainment of the circadian rhythm. It is possible that the ipRGCs contribute to conscious visual perception, either by providing an independent signal to the geniculo-striate pathway, or by interacting with and thus modifying signals arising from “classical” retinal ganglion cells that combine and contrast cone input. Here, we tested for the existence of an interaction by asking if a 350% change in melanopsin stimulation alters psychophysical sensitivity for the detection of luminance flicker. In Experiment 1, we tested for a change in the threshold for detecting luminance flicker in three participants after they adapted to backgrounds with different degrees of tonic melanopsin stimulation. In Experiments 2 and 3, this test was repeated, but now for luminance flicker presented on a transient pedestal of melanopsin stimulation. Across the three experiments, no effect of melanopsin stimulation upon threshold flicker sensitivity was found. Our results suggest that even large changes in melanopsin stimulation do not affect near-threshold, cone-mediated visual perception.

Ultrasound Gray Scale Ratio for the Differential Diagnosis of Papillary Thyroid Microcarcinoma and Benign Micronodule in Patients with Hashimoto’s Thyroiditis

Purpose To investigate the diagnostic value of ultrasound gray scale ratio (UGSR) for differentiating papillary thyroid microcarcinomas (PTMCs) and benign micronodules (BMNs) in patients with HT.Methods The ultrasound images of 285 PTMCs (in 247 patients) and 173 BMNs (in 140 patients) in the HT group, as well as 461 PTMCs (in 417 patients) and 234 BMNs (in 197 patients) in the non-HT group were retrospectively analyzed. All cases were confirmed by histological examinations. The gray scale values of the nodules and surrounding thyroid tissues were measured and subsequently the UGSR was calculated. Receiver operating characteristic curve was used for determining the area under the curve (AUC), optimal UGSR threshold, sensitivity and specificity in differentiating PTMCs and BMNs in the two groups.Results The UGSRs of PTMCs and BMNs were 0.52±0.12 and 0.85±0.24 (P<0.001) in the HT group and 0.57±0.13 and 0.87±0.20 (P<0.001) in the non-HT group, respectively. The differences in the UGSRs of PTMCs were significantly different between the two groups (P<0.001), whereas the difference in the UGSRs of BMNs was not significantly different between the two groups (P=0.416). The AUC, optimal UGSR threshold, sensitivity and specificity of UGSR for differentiating PTMCs and BMNs in the HT and non-HT groups were 0.901 and 0.890, 0.727 and 0.687, 82.05% and 77.46% and 90.67% and 91.23%, respectively.Conclusions UGSR exhibits important diagnostic value for differentiating PTMCs from BMNs in both HT and non-HT groups, and the USGR was lower in the HT group compared with that in the non-HT group.

Melanopic stimulation does not affect psychophysical threshold sensitivity for luminance flicker

In addition to the cone photoreceptors the retina contains intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells express the photopigment melanopsin and are known to be involved in reflexive visual functions such as pupil response and photo-entrainment of the circadian rhythm. It is possible that the ipRGCs contribute to conscious visual perception, either by providing an independent signal to the geniculo-striate pathway, or by interacting with and thus modifying signals arising from "classical" retinal ganglion cells that combine and contrast cone input. Here, we tested for the existence of an interaction by asking if a 350% change in melanopsin stimulation alters psychophysical sensitivity for the detection of luminance flicker. In Experiment 1, we tested for a change in the threshold for detecting luminance flicker in three participants after they adapted to backgrounds with different degrees of tonic melanopsin stimulation. In Experiments 2 and 3, this test was repeated, but now for luminance flicker presented on a transient pedestal of melanopsin stimulation. Across the three experiments, no effect of melanopsin stimulation upon threshold flicker sensitivity was found. Our results suggest that even large changes in melanopsin stimulation do not affect near-threshold, cone-mediated visual perception.

Method for practical calculation of underwater vehicle's television communications

В статье обосновывается и предлагается для практического применения методика расчёта подводных телевизионных коммуникаций, апробированная при проведении испытаний отечественных подводных аппаратов на морских акваториях Белого и Баренцева морей. Последовательно проводится расчет освещенности толщи воды между осветителем и объектом наблюдения; определяется суммарная освещенность на входе объектива телевизионной камеры, создаваемая отраженным от объекта светом и помехой обратного рассеяния; рассчитывается контраст белых и черных объектов. В заключении показан расчет изменения пороговой чувствительности камеры в зависимости от дальности наблюдения. Представленная методика может использоваться при проектировании систем технического зрения обитаемых и необитаемых подводных аппаратов для получения данных о предполагаемых дальностях наблюдения объектов с различными коэффициентами отражения с заданными параметрами прожекторного осветителя. The article proposes a technique for calculating underwater television communications, which was confirmed during tests of domestic underwater vehicles in the waters of the White and Barents Seas. First, the illumination of the water between the illuminator and the object of observation is calculated; then the total illumination at the entrance of the TV camera lens, created by the light reflected from the object and the backscattering interference, is determined; and finally, the contrast of white and black objects is calculated. In conclusion, the calculation of the change in the threshold sensitivity of the camera depending on the observation range is shown. The presented technique can be used in the design of computer vision systems of crewed and unmanned underwater vehicles to obtain data on the estimated observation ranges of objects with different reflection coefficients and with the specified parameters of the searchlight illuminator.

FC 056ESTIMATING ALBUMIN TO CREATININE RATIO FROM PROTEIN TO CREATININE RATIO USING SAME DAY MEASUREMENT: VALIDATION OF EQUATION

Background and Aims According to the KDIGO, severity of chronic kidney disease is defined by glomerular filtration rate and albuminuria. Furthermore, these variables are used for estimating both cardiovascular and end-stage renal disease risk. However, albuminuria is not always available, whereas proteinuria is, notably because of the lower costs of proteinuria. Recently, Weaver & al. developed an equation that estimates urine albumin/creatinine ratio (ACR) from protein/creatinine ratio (PCR). For retrospective analyses in clinical research, it might be interesting to be able to estimate ACR from PCR. The objective of this paper is to assess the performance of Weaver & al. ‘s equation in our population. Method In a University hospital, we retrospectively analysed measurement of ACR and PCR obtained on the same day between May 2018 and March 2020. Different assays were considered to measure urine albumin, creatinine and protein (Roche Cobas from May 2018 to May 2019 and Abbott Alinity from May 2019 to March 2020). Only one (the first available) sample per patient was considered. Patients were then categorized according to the KDIGO classification (A1-A2-A3). We then compared categorization of patients according to KDIGO between measured and estimated ACR. Sensitivity, specificity, positive predictive value and negative predictive value of estimated ACR versus measured ACR were calculated considering two different thresholds: A1 versus A2/3 (ACR 30mg/g) or A1/A2 versus A3 (ACR 300mg/g). Results Comparison was done in 2633 and 2386 patients, with Cobas and Alinity, respectively. Median age was 63 (IQR 19) and 64 (IQR 19) years old, 43 and 41% were women and 74 and 78% were diabetic (albuminuria measurement is refunded for diabetic patients in Belgium) with Cobas and Alinity, respectively. Considering measured ACR, patients were categorized in A1, A2, A3 in 65,6%, 25,5%, and 8,8%, respectively with the Cobas assay. With the Alinity assay, the results were 64,2%, 25,5%; and 10,3%, respectively. Considering estimated ACR, patients were categorized in A1, A2, A3 in 64,7%, 25,7%, and 9,6%, respectively with the Cobas Assay. With the Alinity assay, the results were 62,5%, 25,8% and 11,7%, respectively. Regarding A1-A2 (30mg/g) threshold, sensitivity was 85% and 89%, specificity was 91% and 92%, positive predictive value was 83% and 85%, negative predictive value was 92% and 94% for Cobas and Alinity respectively. Regarding A2-A3 (300mg/g) threshold, sensitivity was 93% and 98%, specificity was 98% for both, positive predictive value was 86% and 87%, negative predictive value was 99% and 99,8% for Cobas and Alinity respectively. Values are presented in table 1. Conclusion We observed a good concordance between estimated and measured ACR. Particularly, no patient in category A3 with measured ACR was categorized A1 with the estimating equations. We also observed that concordance was good regardless of our available assays. Thus, negative predictive value was excellent. In conclusion, ACR should be measured when clinically needed, but an estimated ACR can reasonably be obtained from Weaver’s equation and may provide an accurate estimation for retrospective clinical research.