Bijective Density-Equalizing Quasiconformal Map for Multiply-Connected Open Surfaces

This paper proposes a novel method for computing bijective density-equalizing quasiconformal (DEQ) flattening maps for multiply-connected open surfaces. In conventional density-equalizing maps, shape deformations are solely driven by prescribed constraints on the density distribution, defined as the population per unit area, while the bijectivity and local geometric distortions of the mappings are uncontrolled. Also, prior methods have primarily focused on simply-connected open surfaces but not surfaces with more complicated topologies. Our proposed method overcomes these issues by formulating the density diffusion process as a quasiconformal flow, which allows us to effectively control the local geometric distortion and guarantee the bijectivity of the mapping by solving an energy minimization problem involving the Beltrami coefficient of the mapping. To achieve an optimal parameterization of multiply-connected surfaces, we develop an iterative scheme that optimizes both the shape of the target planar circular domain and the density-equalizing quasiconformal map onto it. In addition, landmark constraints can be incorporated into our proposed method for consistent feature alignment. The method can also be naturally applied to simply-connected open surfaces. By changing the prescribed population, a large variety of surface flattening maps with different desired properties can be achieved. The method is tested on both synthetic and real examples, demonstrating its efficacy in various applications in computer graphics and medical imaging

Generation of Spatiotemporal Vortex Pulses by Simple Diffractive Grating

Spatiotemporal vortex pulses are wave packets that carry transverse orbital angular momentum, exhibiting exotic structured wavefronts that can twist through space and time. Existing methods to generate these pulses require complex setups like spatial light modulators or computer-optimized structures. Here, we demonstrate a new approach to generate spatiotemporal vortex pulses using just a simple diffractive grating. The key is constructing a phase vortex in frequency-momentum space by leveraging symmetry, resonance, and diffraction. Our approach is applicable to any wave system. We use a liquid surface wave platform to directly demonstrate and observe the real-time generation and evolution of spatiotemporal vortex pulses. This straightforward technique provides opportunities to explore pulse dynamics and potential applications across different disciplines

Designing an object-based preproduction tool for multiscreen TV viewing

Multiscreen TV viewing refers to a spectrum of media productions that can be watched using TV and companion screens such as smartphones and tablets. In the last several years, companies are creating companion applications to enrich the TV viewing experience

Enhanced Colorimetric Differentiation between Staphylococcus aureus and Pseudomonas aeruginosa Using a Shape-Encoded Sensor Hydrogel

Herein, we demonstrate a combined fluorescent probe/shape-encoded hydrogel strategy for the fast, sensitive, and selective detection of bacterial species via their characteristic enzymes. A poly(vinyl alcohol) (PVA) hydrogel loaded with the fluorescent probe N,N′-(3-oxo-3H-spiro[isobenzofuran-1,9′-xanthene]-3′,6′-diyl)bis(2,2,3,3,3-pentafluoropropanamide) (ACS-HNE) was designed for the detection of elastase, an enzyme produced by Pseudomonas aeruginosa. Likewise, a chitosan-derived hydrogel was loaded with the fluorescent probe 4-methylumbelliferyl-α-d-glucopyranoside (MUD) by entrapment for the selective detection of α-glucosidase, an enzyme produced by Staphylococcus aureus. For an observation time of 60 min, limits of detection (LODs) of ≤20 nM for elastase and ≤30 pM for α-glucosidase were obtained, which in the latter case is 3 orders of magnitude better than related chitosan systems with covalently coupled substrate. To illustrate the potential utility of these highly sensitive sensor hydrogels as a simple point-of-care test system, shaped hydrogel slabs representing the letters P and S were manufactured to detect P. aeruginosa and S. aureus, respectively. These shapes were shown to provide an additional unique color code under UV illumination corresponding to the characteristic enzyme produced by the corresponding bacteria. This study shows potential for the future development of an effective and simple point-of-care test for the rapid identification of bacterial species that can be operated by nonspecialists

Defects in efferent duct multiciliogenesis underlie male infertility in GEMC1-, MCIDAS- or CCNO-deficient mice

GEMC1 and MCIDAS are geminin family proteins that transcriptionally activate E2F4/5-target genes during multiciliogenesis, including Foxj1 and Ccno. Male mice that lacked Gemc1, Mcidas or Ccno were found to be infertile, but the origin of this defect has remained unclear. Here, we show that all three genes are necessary for the generation of functional multiciliated cells in the efferent ducts that are required for spermatozoa to enter the epididymis. In mice that are mutant for Gemc1, Mcidas or Ccno, we observed a similar spectrum of phenotypes, including thinning of the seminiferous tubule epithelia, dilation of the rete testes, sperm agglutinations in the efferent ducts and lack of spermatozoa in the epididymis (azoospermia). These data suggest that defective efferent duct development is the dominant cause of male infertility in these mouse models, and this likely extends to individuals with the ciliopathy reduced generation of multiple motile cilia with mutations in MCIDAS and CCNO

Architecture of Heptagonal Metallo-macrocycles via Embedding Metal Nodes Into Its Rigid Backbone

Metal-organic macrocycles have received increasing attention not only due to their versatile applications such as molecular recognition, compounds encapsulation, anti-bacteria and others, but also for their important role in the study of structure-property relationship at nano scale. However, most of the constructions utilize benzene ring as the backbone, which restricts the ligand arm angle in the range of 60, 120 and 180 degrees. Thus, the topologies of most metallo-macrocycles are limited as triangles and hexagons, and explorations of using other backbones with large angles and the construction of metallo-macrocycles with more than six edges are very rare. In this study, we present a novel strategy for self-assembly two giant heptagonal metallo-macrocycles with an inner diameter of 5 nm, by embedding metal nodes into the ligand backbone and regulating the ligand arm angle. By complexing with metal ions, the angle between two arms at the 4,4” position of the central terpyridine (tpy) was extended, resulting in ring expansion of the metallo-macrocycle. This approach enabled the construction of giant and more complex metallo- macrocycles that could not be achieved with traditional benzene ring backbones. The characterization of complex molecules often requires the use of multiple techniques, such as multi-dimensional and multinuclear NMR and multidimensional mass spectrometry analysis. Here, we also utilized transmission electron microscopy (TEM) and ultra-high vacuum (∼E-10 torr) low-temperature (∼77 K) scanning tunneling microscopy (UHV-LT-STM) to characterize complex supramolecules. The resulting metallo-macrocycles formed hierarchical self-assembled nanotube structures at larger densities, which is observed by TEM, while UHV-LT-STM was used for direct visualization of individual complex supramolecules deposited on an Au(111) substrate. Our findings indicate that UHV-LT-STM is an effective methodology for characterizing supramolecules at a single molecule level, providing more details of the molecular structure that is difficult to resolve by the resolution of TEM.https://digitalcommons.odu.edu/gradposters2023_sciences/1005/thumbnail.jp