9,316 research outputs found
Perceived Visual Direction near an Occluder
When an opaque object occludes a more distant object, the two eyes often see different parts of the
distant object. Hering s laws of visual direction make an interesting prediction for this situation: the
part seen by both eyes should be seen in a different direction than the part seen by one eye. We
examined whether this prediction holds by asking observers to align a vertical monocular line
segment with a nearby vertical binocular segment. We found it necessary to correct the alignment
data for vergence errors, which were measured in a control experiment, and for monocular spatial
distortions, which were also measured in a control experiment. Settings were reasonably consistent
with Hering's laws when the monocular and binocular targets were separated by 30 arcmin or more.
Observers aligned the targets as if they were viewing them from one eye only when they were
separated by 2 arcmin; this behavior is consistent with an observation reported by Erkelens and
colleagues. The same behavior was observed when the segments were horizontal and when no
visible occluder was present. Perceived visual direction when the two eyes see different parts of a
distant target is assigned in a fashion that minimizes, but does not eliminate, distortions of the shape
of the occluded object
An analysis of binocular slant contrast
When a small frontoparallel surface (a test strip) is surrounded by a larger slanted surface (an
inducer), the test strip is perceived as slanted in the direction opposite to the inducer. This has been
called the depth-contrast effect, but we call it the slant-contrast effect. In nearly all demonstrations of
this effect, the inducers slant is specified by stereoscopic signals, and other signals, such as the texture
gradient, specify that it is frontoparallel. We present a theory of slant estimation that determines surface
slant via linear combination of various slant estimators; the weight of each estimator is proportional to
its reliability. The theory explains slant contrast because the absolute slant of the inducer and the
relative slant between test strip and inducer are both estimated with greater reliability than the absolute
slant of the test strip. The theory predicts that slant contrast will be eliminated if the signals specifying
the inducers slant are consistent with one another. It also predicts reversed slant contrast if the
inducers slant is specified by nonstereoscopic signals rather than by stereo signals. These predictions
were tested and confirmed in three experiments. The first showed that slant contrast is greatly reduced
when the stereo- and nonstereo-specified slants of the inducer are made consistent with one another.
The second showed that slant contrast is eliminated altogether when the stimulus consists of real planes
rather than images on a display screen. The third showed that slant contrast is reversed when the
nonstereo-specified slant of the inducer varies and the stereo-specified slant is zero. We conclude that
slant contrast is a byproduct of the visual systems reconciliation of conflicting information while it
attempts to determine surface slant
Surface Engineering Methods for Powder Bed Printed Tablets to Optimize External Smoothness and Facilitate the Application of Different Coatings
In a previous attempt to achieve ileo-colonic targeting of bovine intestinal alkaline phosphatase (BIAP), we applied a pH-dependent coating, the ColoPulse coating, directly on powder bed printed (PBP) tablets. However, the high surface roughness necessitated an additional sub-coating layer [Nguyen, K. T. T., Pharmaceutics 2022]. In this study, we aimed to find a production method for PBP tablets containing BIAP that allows the direct application of coating systems. Alterations of the printing parameters, binder content, and printing layer height, when combined, were demonstrated to create visually less rough PBP tablets. The addition of ethanol vapor treatment further improved the surfaceâs smoothness significantly. These changes enabled the direct application of the ColoPulse, or enteric coating, without a sub-coating. In vitro release testing showed the desired ileo-colonic release or upper-intestinal release for ColoPulse or enteric-coated tablets, respectively. Tablets containing BIAP, encapsulated within an inulin glass, maintained a high enzymatic activity (over 95%) even after 2 months of storage at 2â8 °C. Importantly, the coating process did not affect the activity of BIAP. In this study, we demonstrate, for the first time, the successful production of PBP tablets with surfaces that are directly coatable with the ColoPulse coating while preserving the stability of the encapsulated biopharmaceutical, BIAP.</p
Application of whole genome and RNA sequencing to investigate the genomic landscape of common variable immunodeficiency disorders.
Common Variable Immunodeficiency Disorders (CVIDs) are the most prevalent cause of primary antibody failure. CVIDs are highly variable and a genetic causes have been identified in <5% of patients. Here, we performed whole genome sequencing (WGS) of 34 CVID patients (94% sporadic) and combined them with transcriptomic profiling (RNA-sequencing of B cells) from three patients and three healthy controls. We identified variants in CVID disease genes TNFRSF13B, TNFRSF13C, LRBA and NLRP12 and enrichment of variants in known and novel disease pathways. The pathways identified include B-cell receptor signalling, non-homologous end-joining, regulation of apoptosis, T cell regulation and ICOS signalling. Our data confirm the polygenic nature of CVID and suggest individual-specific aetiologies in many cases. Together our data show that WGS in combination with RNA-sequencing allows for a better understanding of CVIDs and the identification of novel disease associated pathways
Approximation algorithms for replenishment problems with fixed turnover times
We introduce and study a class of optimization problems we coin replenishment problems with fixed turnover times: a very natural model that has received little attention in the literature. Nodes with
Inverse Association between trans Isomeric and Long-Chain Polyunsaturated Fatty Acids in Pregnant Women and Their Newborns: Data from Three European Countries
Background: trans unsaturated fatty acids are thought to interfere with essential fatty acid metabolism. To extend our knowledge of this phenomenon, we investigated the relationship between trans isomeric and long-chain polyunsaturated fatty acids (LCPUFA) in mothers during pregnancy and in their infants at birth. Methods: Fatty acid composition of erythrocyte phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was determined in Spanish (n = 120), German (n = 78) and Hungarian (n = 43) women at the 20th and 30th week of gestation, at delivery and in their newborns. Results: At the 20th week of gestation, the sum of trans fatty acids in PE was significantly (p < 0.01) lower in Hungarian [0.73 (0.51), % wt/wt, median (IQR)] than in Spanish [1.42 (1.36)] and German [1.30 (1.21)] women. Docosahexaenoic acid (DHA) values in PE were significantly (p < 0.01) higher in Hungarian {[}5.65 (2.09)] than in Spanish [4.37 (2.60)] or German [4.39 (3.3.2)] women. The sum of trans fatty acids significantly inversely correlated to DHA in PCs in Spanish (r = -0.37, p < 0.001), German (n = -0.77, p < 0.001) and Hungarian (r = -0.35, p < 0.05) women, and in PEs in Spanish (r = -0.67, p < 0.001) and German (r = -0.71, p < 0.001), but not in Hungarian (r = -0.02) women. Significant inverse correlations were seen between trans fatty acids and DHA in PEs at the 30th week of gestation (n = 241, r = -0.52, p < 0.001), at delivery (n = 241, r = -0.40, p < 0.001) and in cord lipids (n = 218, r = -0.28, p < 0.001). Conclusion: Because humans cannot synthesize trans isomeric fatty acids, the data obtained in the present study support the concept that high maternal trans isomeric fatty acid intake may interfere with the availability of LCPUFA both for the mother and the fetus. Copyright (C) 2011 S. Karger AG, Base
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