457 research outputs found
Voltage-dependent anion-selective channels VDAC2 and VDAC3 are abundant proteins in bovine outer dense fibers, a cytoskeletal component of the sperm flagellum
Outer dense fibers (ODF) are specific subcellular components of the sperm flagellum. The functions of ODF have not yet been clearly elucidated. We have investigated the protein composition of purified ODF from bovine spermatozoa and found that one of the most abundant proteins is a 30-32-kDa polypeptide. This protein was analyzed by sequencing peptides derived following limited proteolysis. Peptide sequences were found to match VDAC2 and VDAC3. VDACs (voltage-dependent, anion-selective channels) or eukaryotic porins are a group of proteins first identified in the mitochondrial outer membrane that are able to form hydrophilic pore structures in membranes. In mammals, three VDAC isoforms (VDAC1, -2, -3) have been identified by cDNA cloning and sequencing. Antibodies against synthetic peptides specific for the three mammal VDAC isoforms were generated in rabbits. Their specificity was demonstrated by immunoblotting using recombinant VDAC1, -2, and -3. In protein extracts of bovine spermatozoa, VDAC1, -2, and -3 were detected by specific antibodies, while only VDAC2 and -3 were found as solubilized proteins derived from purified bovine ODFs. Immunofluorescence microscopy of spermatozoa revealed that anti-VDAC2 and anti-VDAC3 antibodies clearly bound to the sperm flagellum, in particular to the ODF. Transmission electron immunomicroscopy supported the finding that VDAC2 protein is abundant in the ODF. Since the ODF does not have any known membranous structure, it is tempting to speculate that VDAC2 and VDAC3 might have an alternative structural organization and different functions in ODF than in mitochondria
The 4C framework: Towards a holistic understanding of consumer engagement with augmented reality
Highlights The 4C framework highlights four unique characteristics of AR: Consumer, Content, Context, and Computing Device. Engagement with AR derives from an alignment of the 4 Cs. The paper advances theory by using the lens of complexity theory to explain how to engage consumers in AR experiences. The framework offers significant implications for managers and scholars. It allows systematic approaches to assess, communicate, and develop AR applications across various disciplines. Abstract Augmented Reality (AR) is an emerging concept that impacts many disciplines, such as business, marketing, tourism, gaming, humanâcomputer interaction, and manufacturing. Surprisingly, many scholarly and practical discussions overlook the fundamental primary factors that distinguish AR from other concepts, namely, that it involves a computing device that integrates virtual content into a consumer\u27s perception of the real world in a specific context. The current article addresses this gap in the literature by proposing the 4C framework (based on the 4Cs: consumer, content, context, and computing device; pronounced: foresee) that highlights the importance of, and interplay among these four factors. Building on configurational theory, the framework calls for the systematic identification of additional AR-relevant factors across the 4Cs. Scholars can use this framework to systematically identify research gaps and variables of interest. Practitioners across various disciplines can employ the framework to systematically assess, communicate, and develop AR use cases
Context in augmented reality marketing: Does the place of use matter?
Augmented reality (AR) integrates virtual content into a consumer\u27s perception of the real world. While academic interest in AR is growing, most prior research has focused on consumer evaluations of AR content and neglected the physical context in which AR content is consumed. Addressing this research gap, two experimental studies showed that context (e.g., experiencing a virtual sofa at home vs. in a university classroom) impacts consumer judgments and evaluations. The results reveal two primary effects of context. First, contexts in which virtual objects meet users\u27 personal and cultural expectations associated with a specific location (e.g., a sofa in a living room) increase plausibility. However, such functionally appropriate contexts (counterintuitively) decrease local presence (i.e., the perception that the virtual product is âhereâ). Study 2 extends this model by showing that plausibility (a rational and deliberate assessment of AR content) and local presence both impact utilitarian benefits, whereas local presence has a stronger effect on perceived physical tangibility. The findings extend prior theory on the psychological mechanisms impacting judgment and presence in AR, and they provide managers with important insights regarding the influence of context on downstream variables in their AR and metaverse marketing strategies
What is XR? Towards a Framework for Augmented and Virtual Reality
Augmented Reality (AR), Virtual Reality (VR), Mixed Reality, and Extended Reality (often â misleadingly â abbreviated as XR) are commonly used terms to describe how technologies generate or modify reality. However, academics and professionals have been inconsistent in their use of these terms. This has led to conceptual confusion and unclear demarcations. Inspired by prior research and qualitative insights from XR professionals, we discuss the meaning and definitions of various terms and organize them in our proposed framework. As a result, we conclude that (1) XR should not be used to connote extended reality, but as a more open approach where the X implies the unknown variable: xReality; (2) AR and VR have fundamental differences and thus should be treated as different experiences; (3) AR experiences can be described on a continuum ranging from assisted reality to mixed reality (based on the level of local presence); and (4), VR experiences can be conceptualized on a telepresence-continuum ranging from atomistic to holistic VR
Traffic jams induced by rare switching events in two-lane transport
We investigate a model for driven exclusion processes where internal states are assigned to the particles. The latter account for diverse situations, ranging from spin states in spintronics to parallel lanes in intracellular or vehicular traffic. Introducing a coupling between the internal states by allowing particles to switch from one to another induces an intriguing polarization phenomenon. In a mesoscopic scaling, a rich stationary regime for the density profiles is discovered, with localized domain walls in the density profile of one of the internal states being feasible. We derive the shape of the density profiles as well as resulting phase diagrams analytically by a mean-field approximation and a continuum limit. Continuous as well as discontinuous lines of phase transition emerge, their intersections induce multi-critical behaviour
A diffusive system driven by a battery or by a smoothly varying field
We consider the steady state of a one dimensional diffusive system, such as
the symmetric simple exclusion process (SSEP) on a ring, driven by a battery at
the origin or by a smoothly varying field along the ring. The battery appears
as the limiting case of a smoothly varying field, when the field becomes a
delta function at the origin. We find that in the scaling limit, the long range
pair correlation functions of the system driven by a battery turn out to be
very different from the ones known in the steady state of the SSEP maintained
out of equilibrium by contact with two reservoirs, even when the steady state
density profiles are identical in both models
Limited Lifespan of Fragile Regions in Mammalian Evolution
An important question in genome evolution is whether there exist fragile
regions (rearrangement hotspots) where chromosomal rearrangements are happening
over and over again. Although nearly all recent studies supported the existence
of fragile regions in mammalian genomes, the most comprehensive phylogenomic
study of mammals (Ma et al. (2006) Genome Research 16, 1557-1565) raised some
doubts about their existence. We demonstrate that fragile regions are subject
to a "birth and death" process, implying that fragility has limited
evolutionary lifespan. This finding implies that fragile regions migrate to
different locations in different mammals, explaining why there exist only a few
chromosomal breakpoints shared between different lineages. The birth and death
of fragile regions phenomenon reinforces the hypothesis that rearrangements are
promoted by matching segmental duplications and suggests putative locations of
the currently active fragile regions in the human genome
Molecular Spiders in One Dimension
Molecular spiders are synthetic bio-molecular systems which have "legs" made
of short single-stranded segments of DNA. Spiders move on a surface covered
with single-stranded DNA segments complementary to legs. Different mappings are
established between various models of spiders and simple exclusion processes.
For spiders with simple gait and varying number of legs we compute the
diffusion coefficient; when the hopping is biased we also compute their
velocity.Comment: 14 pages, 2 figure
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