Isometric Texture Mapping for Free-form Surfaces

Texture mapping is a frequently exploited technique in computer graphics aimed at the emulation of high-resolution details in surfaces. In this paper we present a distance-ratios preservation method for bivariate raster texture mapping to free-form surfaces in an arbitrarily precise manner. The proposed method reduces the original general problem of computing the inverse of a three-dimensional parametric surface mapping into a problem of two-dimensional image warping. Several examples that demonstrate the proposed approach are also provided.     

Integration of Data from Liquid–Liquid Phase Separation Databases Highlights Concentration and Dosage Sensitivity of LLPS Drivers

Liquid–liquid phase separation (LLPS) is a molecular process that leads to the formation of membraneless organelles, representing functionally specialized liquid-like cellular condensates formed by proteins and nucleic acids. Integrating the data on LLPS-associated proteins from dedicated databases revealed only modest agreement between them and yielded a high-confidence dataset of 89 human LLPS drivers. Analysis of the supporting evidence for our dataset uncovered a systematic and potentially concerning difference between protein concentrations used in a good fraction of the in vitro LLPS experiments, a key parameter that governs the phase behavior, and the proteomics-derived cellular abundance levels of the corresponding proteins. Closer scrutiny of the underlying experimental data enabled us to offer a sound rationale for this systematic difference, which draws on our current understanding of the cellular organization of the proteome and the LLPS process. In support of this rationale, we find that genes coding for our human LLPS drivers tend to be dosage-sensitive, suggesting that their cellular availability is tightly regulated to preserve their functional role in direct or indirect relation to condensate formation. Our analysis offers guideposts for increasing agreement between in vitro and in vivo studies, probing the roles of proteins in LLPS.     

2 1/2 D Visual Servoing with Respect to Unknown Objects Through a New Estimation Scheme of Camera Displacement

Classical visual servoing techniques need a strong a priori knowledge of the shape and the dimensions of the observed objects. In this paper, we present how the 2 1/2 D visual servoing scheme we have recently developed, can be used with unknown objects characterized by a set of points. Our scheme is based on the estimation of the camera displacement from two views, given by the current and desired images. Since vision-based robotics tasks generally necessitate to be performed at video rate, we focus only on linear algorithms. Classical linear methods are based on the computation of the essential matrix. In this paper, we propose a different method, based on the estimation of the homography matrix related to a virtual plane attached to the object. We show that our method provides a more stable estimation when the epipolar geometry degenerates. This is particularly important in visual servoing to obtain a stable control law, especially near the convergence of the system. Finally, experimental results confirm the improvement in the stability, robustness, and behaviour of our scheme with respect to classical methods.     

Genes Involved in the Endoplasmic Reticulum N-Glycosylation Pathway of the Red Microalga Porphyridium sp.: A Bioinformatic Study

N-glycosylation is one of the most important post-translational modifications that influence protein polymorphism, including protein structures and their functions. Although this important biological process has been extensively studied in mammals, only limited knowledge exists regarding glycosylation in algae. The current research is focused on the red microalga Porphyridium sp., which is a potentially valuable source for various applications, such as skin therapy, food, and pharmaceuticals. The enzymes involved in the biosynthesis and processing of N-glycans remain undefined in this species, and the mechanism(s) of their genetic regulation is completely unknown. In this study, we describe our pioneering attempt to understand the endoplasmic reticulum N-Glycosylation pathway in Porphyridium sp., using a bioinformatic approach. Homology searches, based on sequence similarities with genes encoding proteins involved in the ER N-glycosylation pathway (including their conserved parts) were conducted using the TBLASTN function on the algae DNA scaffold contigs database. This approach led to the identification of 24 encoded-genes implicated with the ER N-glycosylation pathway in Porphyridium sp. Homologs were found for almost all known N-glycosylation protein sequences in the ER pathway of Porphyridium sp.; thus, suggesting that the ER-pathway is conserved; as it is in other organisms (animals, plants, yeasts, etc.).     

Gaucher Disease Diagnosis Using Lyso-Gb1 on Dry Blood Spot Samples: Time to Change the Paradigm?

For years, the gold standard for diagnosing Gaucher disease (GD) has been detecting reduced β-glucocerebrosidase (GCase) activity in peripheral blood cells combined with GBA1 mutation analysis. The use of dried blood spot (DBS) specimens offers many advantages, including easy collection, the need for a small amount of blood, and simpler transportation. However, DBS has limitations for measuring GCase activity. In this paper, we recount our cross-sectional study and publish seven years of experience using DBS samples and levels of the deacylated form of glucocerebroside, glucosylsphingosine (lyso-Gb1), for GD diagnosis. Of 444 screened subjects, 99 (22.3%) were diagnosed with GD at a median (range) age of 21 (1–78) years. Lyso-Gb levels for genetically confirmed GD patients vs. subjects negative to GD diagnosis were 252 (9–1340) ng/mL and 5.4 (1.5–16) ng/mL, respectively. Patients diagnosed with GD1 and mild GBA1 variants had lower median (range) lyso-Gb1, 194 (9–1050), compared to GD1 and severe GBA1 variants, 447 (38–1340) ng/mL, and neuronopathic GD, 325 (116–1270) ng/mL (p = 0.001). Subjects with heterozygous GBA1 variants (carrier) had higher lyso-Gb1 levels, 5.8 (2.5–15.3) ng/mL, compared to wild-type GBA1, 4.9 (1.5–16), ng/mL (p = 0.001). Lyso-Gb1 levels, median (range), were 5 (2.7–10.7) in heterozygous GBA1 carriers with Parkinson’s disease (PD), similar to lyso-Gb1 levels in subjects without PD. We call for a paradigm change for the diagnosis of GD based on lyso-Gb1 measurements and confirmatory GBA1 mutation analyses in DBS. Lyso-Gb1 levels could not be used to differentiate between heterozygous GBA1 carriers and wild type.     

Enhancement by image-dependent warping

All image warping algorithms to date are image-independent, namely, relate only to the geometry of the image plane, ignoring the content of the image. We show that taking the image content into account yields elaborate warping schemes which may be used to enhance, sharpen and scale images. Sharpening the image is achieved by "squashing" the pixels in edge areas, and "stretching" the pixels in flat areas. Since image pixels are only moved, not modified, some drawbacks of classical linear filtering methods are avoided. We also lay the mathematical foundation for the use of an image-dependent warping scheme in traditional warping applications, such as distortion minimization.     

Grain-boundary segregation in an Al-8 wt % Mg alloy

The grain-boundary segregation of Mg atoms in a high-purity Al-8wt% Mg alloy, water quenched from the solution heat-treatment temperature, has been investigated by energy dispersive X-ray microanalysis in a TEM/STEM electron microscope. Many grain boundaries showed a segregation of Mg atoms to a level 2 to 3 times higher than the alloy composition. In the as-quenched state, Mg was uniformly distributed along the grain boundaries, but formed clusters during ageing at room temperature. Hydrogen bubbles were often associated with these Mg-rich regions. Mg-depleted zones were observed adjacent to most boundaries, but in most cases on only one side of the boundary.     

Participative goal-setting: Social, motivational, and cognitive factors.

Examined 3 explanations of why participation in goal setting may lead to increased performance—the social factor of group discussion, the motivational factor of involvement in goal setting, and the cognitive factor of information. A 2?×?2?×?2 experimental design (low and high levels of group discussion, involvement, and information) was used to study 96 predominantly male white collar employees (aged 23–58 yrs) who worked on a simulated personnel selection task. Results indicate that the social and motivational factors of participation increased performance quantity, incidental learning, goal acceptance, group commitment, and satisfaction. The motivational and cognitive factors significantly contributed to performance quality but the cognitive factor did not significantly affect performance quantity and work attitudes. It is suggested that a combination of the 3 factors leads to the highest level of performance. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of the laser radiation wavelength on the energy threshold of initiation of heavy metal azides

The behavior of silver and lead azides (laminated and filiform crystals, pressed powders) with initiation of their explosive decomposition by a laser pulse is studied. The initiation energy thresholds are measured during irradiation at wavelengths of 1064, 532, 354.7, and 266 nm corresponding to four harmonics of laser radiation. Irradiation is performed under conditions with the sample surface being open or covered with a transparent dielectric (quartz plate) with a pressing force up to 5 · 10⁸ N/m². Surface covering does not exert any significant effect on the initiation energy threshold in the domain of transparency of the heavy metal azide matrix (first and second radiation harmonics). In the domain of bandgap absorption (fourth harmonic), the initiation threshold strongly depends on the surface conditions (open/covered). The results are discussed from the viewpoint of the influence of the transparent substrate on gas-dynamic unloading of the heat spot, which is formed in the domain of bandgap absorption owing to laser radiation absorption in a thin subsurface layer.     

Improved finite difference method for equilibrium problems based on differentiation of the partial differential equations and the boundary conditions

A numerical algorithm for producing high-order solutions for equilibrium problems is presented. The approximated solutions are improved by differentiating both the governing partial differential equations and their boundary conditions. The advantages of the proposed method over standard finite difference methods are: the possibility of using arbitrary meshes; the possibility of using simultaneously approximations with different (distinct) orders of accuracy at different locations in the problem domain; an improvement in approximating the boundary conditions; the elimination of the need for ‘fictitious’ or ‘external’ nodal points in treating the boundary conditions. Furthermore, the proposed method is capable of reaching approximate solutions which are more accurate than other finite difference methods, when the same number of nodal points participate in the local scheme. A computer program was written for solving two-dimensional problems in elasticity. The solutions of a few examples clearly illustrate these advantages.