Visual fatigue evaluation of field sequential stereoscopic 3D display using near point distance

The purpose of this paper was to evaluate quantitatively visual fatigue encountered in viewing stereoscopic 3D television. By examining the difference in the visual function involved in watching 2D and stereoscopic 3D displays, we could extract only the effect on visual perception in stereoscopic 3D television. Since the visual fatigue with the 3D display may be caused by the discrepancy between convergence and accommodation, the near point distances were measured by an Accommodo Polyrecorder, where Landolt's ring was pursued with binocularity. Five subjects, all employees of NEC Corporation, participated in the experiment. All subjects had normal or corrected-to-normal vision. Two of the subjects watched a 3D video movie. After a week, they watched another video movie in 2D. The rest of them watched the movies in reverse order. One video movie viewing requires about 120 minutes. The near point distances were measured before and after watching for 30, 60, 90 and 120 minutes. The 3D television system used here is a 3D video disc system with field sequence using glasses with liquid crystal shutters. In the case of 2D, each subject wore the glasses whose shutters were kept open. In the experiment, instruction to watch the video movies in a relaxed posture was given. There was a significant effect in regard to 3D/2D treatments on the change rates of the near point distance measured after watching every 30 minutes to one before watching. In addition, the change rates in 3D watching after 60, 90 and 120 minutes were significantly increased, compared with the corresponding rates in 2D.(ABSTRACT TRUNCATED AT 250 WORDS)     

An environment for three-dimensional shaded perspective display of cell components

An integrated environment for converting electron microscopic profile images into shaded perspective displays is described. Its application, reported here, is to the display of various cell organelles; it can also be used for other image acquisition modalities. What separates this application from other, primarily medical ones, is its complexity, since dictyosomes have been employed for the development of the display program. The surface profile structures of these organelles are among the most complicated being processed for scientific applications. Therefore, a high degree of interactivity had to be integrated into the three-dimensional image processing described.     

Protein cell surface display in Gram-positive bacteria: from single protein to macromolecular protein structure

In the course of evolution, Gram-positive bacteria, defined here as prokaryotes from the domain Bacteria with a cell envelope composed of one biological membrane (monodermita) and a cell wall composed at least of peptidoglycan and covalently linked teichoic acids, have developed several mechanisms permitting to a cytoplasmic synthesized protein to be present on the bacterial cell surface. Four major types of cell surface displayed proteins are currently recognized: (i) transmembrane proteins, (ii) lipoproteins, (iii) LPXTG-like proteins and (iv) cell wall binding proteins. The subset of proteins exposed on the bacterial cell surface, and thus interacting with extracellular milieu, constitutes the surfaceome. Here, we review exhaustively the current molecular mechanisms involved in protein attachment within the cell envelope of Gram-positive bacteria, from single protein to macromolecular protein structure.     

Multiple display of peptides and proteins on a macromolecular scaffold derived from a multienzyme complex

The acyltransferase components (E2) from the family of 2-oxo acid dehydrogenase multienzyme complexes form large protein scaffolds, to which multiple copies of peripheral enzymes bind tightly but non-covalently. Sixty copies of the E2 polypeptide from the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus assemble to form a pentagonal dodecahedral scaffold with icosahedral symmetry. This protein scaffold can be modified to present foreign peptides and proteins on its surface. We show that it is possible to display two epitopes (MAL1 and MAL2) from the circumsporozoite CS proteins of Plasmodium falciparum and Plasmodium berghei, respectively, and a green fluorescent protein (EGFP), on the E2 surface. Immunization with an E2 scaffold displaying the MAL1 epitope elicited MAL1-specific antibodies in rabbits. EGFP (25 kDa) displayed as an N-terminal fusion in each of the 60 copies of the E2 chain folded into its active form, as judged by its fluorescence and detection in localized foci in Escherichia coli cells in vivo. Simultaneous display of a hexahistidine affinity tag, the MAL1 epitope and the green fluorescent protein, all on the same E2 scaffold, could be achieved by reversible denaturation and reassembly of mixtures of appropriately modified E2 chains. This new methodology offers several important advantages over other current display technologies, not least in the size of insert that can be accommodated and the multiplicity of display that can be achieved.     

Minimum spanning ordination — a graphic-analytical technique for three-dimensional ordination display

Problems of display and interpretation often associated with ordination techniques are briefly discussed. Minimum spanning ordination (MSO) is put forward as offering a meaningful compromise between the limitations of two-dimensional representation and three-dimensional complexity. The method incorporates the use of a minimum spanning tree together with a graphic spherical perspective of points in the third dimension. It is suggested that where this approach is used with reduction analysis, i.e. with centroids of representative clusters, interpretation is much improved and inherent distortions likely to result from techniques such as principal component analysis are more readily exposed.     

Neuronal model for stereoscopic vision

A neuronal model for stereopsis is described and simulated. Without the assumption of specific feature detectors, objects are unambiguously located in three-dimensional visual space. Random-dot stereograms are correctly resolved in depth with stimulus details conserved within planar contours.     

Microcomputer-based image analysis systems for two-dimensional electrophoresis gels

The intent of this overview is to provide the readers, especially those who are currently conducting two-dimentional electrophoresis, a basic understanding in the construction and use of microcomputer-based systems for the analysis of protein profiles generated by two-dimensional gel electrophoresis. In addition, a microcomputer-based system, employing fixed-point operations and effective algorithms, has been evaluated. The validity of this system has been demonstrated by using the two-dimensional silver-stained gels and fluorograms derived from the rat prostate. It is concluded that the present system can be used to aid the analysis of two-dimensional electrophoresis gels. An overall consideration of hardware and software components of a computer-based system is briefly discussed.     

Complex macromolecular chimeras

By combining two living polymerizations, anionic and ring opening (ROP), the following novel multiblock multicomponent linear and miktoarm star (micro-star) polymer/polypeptide hybrids (macromolecular chimeras) were synthesized: Linear, PBLL-b-PBLG-b-PS-b-PBLG-b-PBLL; 3micro-stars, (PS)2(PBLG or PBLL), (PS)(PI)(PBLG or PBLL); 4micro-stars, (PS)2[P(alpha-MeS)](PBLG or PBLL), (PS)2(PBLG or PBLL)2 [PS, polystyrene; PI, polyisoprene; P(alpha-MeS), poly(alpha-methylstyrene); PBLG, poly(gamma-benzyl-L-glutamate); and PBLL, poly(-tert-butyloxycarbonyl-L-lysine)]. The procedure involves (a) the synthesis of end- or in-chain amino-functionalized polymers, by anionic polymerization high vacuum techniques and appropriate linking chemistry and (b) the use of the amino groups for the ROP of alpha-amino acid carboxyanhydrides (NCAs). Molecular characterization revealed the high molecular weight and compositional homogeneity of the macromolecular chimeras prepared. The success of the synthesis was based mainly on the high vacuum techniques used for the ROP of NCAs, ensuring the avoidance of unwanted polymerization mechanisms and termination reactions.     

The stereoscopic anisotropy affects manual pointing

Although binocular disparity can in principle provide absolute depth information, perceived stereoscopic depth depends on the relative disparities between points and their spatial arrangement. An example of this is the stereoscopic anisotropy--observers typically perceive less depth for stereoscopic surfaces when depth varies in the horizontal direction than in the vertical direction. We investigated whether this anisotropy also affects manual pointing. Participants were presented with stereograms depicting surfaces that were slanted in depth about either a horizontal axis (inclination) or a vertical axis (slant), and were asked either to point to the edge of a surface, or to estimate its inclination or slant. For both tasks, a clear anisotropy was observed, with participants perceiving greater depth, and also pointing out steeper surfaces, for inclined surfaces than for slanted surfaces. We conclude that both perception and the control of action are subject to a similar stereoscopic anisotropy, and that performance on the two tasks relies on similar depth processing mechanisms.     

Computer graphics program to reveal the dependence of the gross three-dimensional structure of the B-DNA double helix on primary structure.

Programs are presented to plot the gross three-dimensional structure of the DNA double helix with the base sequence as input information. The rules that determine the overall structure of the double helix are those that predict the dependence of local helix parameters (specifically, helix twist angle and relative basepair roll angle) on sequence. For this purpose, the user can select either the Calladine-Dickerson parameters or the Tung-Harvey parameters. These programs can be used as tools to investigate the variation of DNA tertiary structure with sequence, which may play an important role in the sequence-specific recognition of DNA by proteins.