Circular Topography Research Articles

Patterned PVA Hydrogels with 3D Petri Dish® Micro-Molds of Varying Topography for Spheroid Formation of HeLa Cancer Cells: In Vitro Assessment.

Cell spheroids are an important three-dimensional (3D) model for in vitro testing and are gaining interest for their use in clinical applications. More natural 3D cell culture environments that support cell-cell interactions have been created for cancer drug discovery and therapy applications, such as the scaffold-free 3D Petri Dish® technology. This technology uses reusable and autoclavable silicone micro-molds with different topographies, and it conventionally uses gelled agarose for hydrogel formation to preserve the topography of the selected micro-mold. The present study investigated the feasibility of using a patterned Poly(vinyl alcohol) hydrogel using the circular topography 12-81 (9 × 9 wells) micro-mold to form HeLa cancer cell spheroids and compare them with the formed spheroids using agarose hydrogels. PVA hydrogels showed a slightly softer, springier, and stickier texture than agarose hydrogels. After preparation, Fourier transform infrared (FTIR) spectra showed chemical interactions through hydrogen bonding in the PVA and agarose hydrogels. Both types of hydrogels favor the formation of large HeLa spheroids with an average diameter of around 700-800 µm after 72 h. However, the PVA spheroids are more compact than those from agarose, suggesting a potential influence of micro-mold surface chemistry on cell behavior and spheroid formation. This was additionally confirmed by evaluating the spheroid size, morphology, integrity, as well as E-cadherin and Ki67 expression. The results suggest that PVA promotes stronger cell-to-cell interactions in the spheroids. Even the integrity of PVA spheroids was maintained after exposure to the drug cisplatin. In conclusion, the patterned PVA hydrogels were successfully prepared using the 3D Petri Dish® micro-molds, and they could be used as suitable platforms for studying cell-cell interactions in cancer drug therapy.

Plane SV-waves scattering by seawater convex surface topography and underlying lined tunnel in a saturated half-space

Analytical solutions of boundary-valued problems for aboveground topography and underground buried structures, especially for sites with overlying seawater, have always been challenging. Based on the region decomposition technique (RDT) and Hankel integral transform method (HITM), SV-waves scattering by the convex circular topography with seawater and underlying tunnel in a saturated half-space is solved. The primary problem is tackling additional scattered waves introduced by the water–soil interface and convex topography, while ensuring boundary conditions are all met. To this end, scattering wave potential functions in cylindrical coordinates are first transformed into the Hankel integral form in Cartesian coordinates. This greatly facilitates the straightforward application of free boundary conditions at the soil–seawater flat interface, rather than making a large circular arc approximate assumption, which, in turn, avoids the resultant accumulating errors. Secondly, scattering problem to be solved is mathematically and analytically formulated as solving a 5 × 5 linear equation system comprised of wave functions inside the convex topography and lining tunnel while satisfying all physical continuous boundary conditions. This is the main innovation and resulting consequence from the theoretical derivation process. Finally, validation of numerical examples between this paper, existing studies and theoretical analysis further demonstrates the reliability and general adaptability of solutions. Parametric studies of the incident SV waves are conducted to investigate the spatially varying seismic response. The effects of SV-waves incident angles and frequencies, tunnel burial depth, tunnel lining thickness, saturated soil porosity, and seawater depth are investigated and analyzed in detail. This study provides a feasible scheme of investigating the dynamic response of complex submarine sites, which is of great significance for both theoretical value and engineering purposes.

A Numerical Assessment of the Efficacy of a Topography Design with Increasing Gradient Complexity for Filtering Biofouling Material through the Membrane Module of a Water Treatment System

Biofouling can also be defined as the micro- / macro- organisms stuck on the surface that has been submerged in water. This is normally found in marine industry and water treatment industry. There are 3 ways of antifouling where the 3rd method surface modification was the main point to be focused on. Surface modification has high potential for antifouling performance and is not harmful to the ecosystem. In this research study was to find out the efficacy of antifouling performance with increasing the gradient complexity. The 2 models used were smooth topography and circular topography and have been manipulated and simulated with WorkBench 2020, Computational Fluid Dynamic (CFD). The results were simulated with the correct meshed and models. The simulated results were converged and 2 hydrodynamic variables; velocity and wall shear were used to check the efficacy of antifouling performance.

Reconnaissance survey of the Duolun ring structure in Inner Mongolia: Not an impact structure

AbstractThe Duolun basin, which is located in Inner Mongolia, China, has been proposed to be an impact structure with an apparent rim diameter of about 70, or even 170 km. The designation as an impact structure was based on its nearly circular topography, consisting of an annular moat that surrounds an inner hummocky region, and the widespread occurrences of various igneous rocks, polymict breccias, and deformed crustal rocks. Critical shock metamorphic evidence is not available to support the impact hypothesis. We conducted two independent reconnaissance field surveys to this area and studied the lithology both within and outside of the ring structure. We collected samples from all lithologies that might contain evidence of shock metamorphism as suggested by their locations, especially those sharing similar appearances with impact breccias, suevites, impact melt rocks, and shatter cones. Field investigation, together with thin‐section examination, discovered that the suspected impact melt rocks are actually Early Cretaceous and Late Jurassic lava flows and pyroclastic deposits of rhyolitic to trachytic compositions, and the interpreted impact glass is typical volcanic glass. Petrographic analyses of all the samples reveal no indications for shock metamorphic overprint. All these lines of evidence suggest that the Duolun basin was not formed through impact cratering. The structural deformation and spatial distribution pattern of the igneous rocks suggest that the Duolun basin is most likely a Jurassic–Cretaceous complex rhyolite caldera system that has been partly filled with sediments forming an annular basin, followed by resurgent doming of the central area.

Self-Powered Active Sensor with Concentric Topography of Piezoelectric Fibers

In this study, we demonstrated a flexible and self-powered sensor based on piezoelectric fibers in the diameter range of nano- and micro-scales. Our work is distinctively different from previous electrospinning research; we fabricated this apparatus precisely via near-field electrospinning which has a spectacular performance to harvest mechanical deformation in arbitrary direction and a novel concentrically circular topography. There are many piezoelectric devices based on electrospinning polymeric fibers. However, the fibers were mostly patterned in parallel lines and they could be actuated in limited direction only. To overcome this predicament, we re-arranged the parallel alignment into concentric circle pattern which made it possible to collect the mechanical energy whenever the deformation is along same axis or not. Despite the change of topography, the output voltage and current could still reach to 5 V and 400 nA, respectively, despite the mechanical deformation was from different direction. This new arbitrarily directional piezoelectric generator with concentrically circular topography (PGCT) allowed the piezoelectric device to harvest more mechanical energy than the one-directional alignment fiber-based devices, and this PGCT could perform even better output which promised more versatile and efficient using as a wearable electronics or sensor.

Beach vortices near circular topography

Finite-area monopolar vortices which propagate around topography without change in shape are computed for circular seamounts and wells including the limiting cases of each: islands and infinitely deep wells. The time-dependent behaviour of vortex pairs propagating toward circular topography is also examined. Trajectories of point-vortex pairs exterior to the topography are found and compared to trajectories of vortex patches computed using contour dynamics.

Potential of impact-structure hydrocarbon plays in continental Southeast Asia

The pre-Tertiary of continental SE Asia, the Indosinia and Sundaland tectonic blocks, most probably hosts a number of brecciated impact structures with good reservoir properties. Hydrocarbons that migrated or re-migrated during the Tertiary may have accumulated in such structures where top seal is present and these structures therefore constitute a potential hydrocarbon play. In the known sedimentary basins of Sundaland, the pre-Tertiary lies too deep or too shallow to be of commercial interest to the petroleum industry. The shallow basement has been considered to possess less proven trap styles of the stratigraphic and buried hills categories. Very recently, three areas onshore Peninsular Malaysia were proven products of meteorite impacts. Their definitive features of shock metamorphism comprise multi-directional cleavage in quartz crystals, mosaicism in their optical extinction, and suevite breccia in association with circular topography. About several dozen of circular features have been identified in the peninsula and study is in progress to ascertain their nature. The peninsular area constitutes less than 15 per cent of the pre-Tertiary expanse of Sundaland. The presence of more impact structures in pre-Tertiary Sundaland is undeniable. In addition, the wide offshore areas of shallow basement ( > 1 km deep) bordering the petroleum basins are worth exploring for this new play.

Eeg alpha phase at stimulus onset significantly affects the amplitude of the P3 ERP component

Analysis of the relationship between prestimulus EEG alpha phase and the subsequent ERP has proved difficult because of the non-Euclidean nature of phase measurements. In this study, we employed a conventional P3 templating method of single-trial analysis to identify the P3 component in target auditory oddball data from 25 normals. As in previous studies, the absence or near absence of P3 from a subset of single-trials was clearly demonstrated. We investigated this phenomenon to determine whether those single-trials with a large P3 had a different prestimulus alpha phase from those with a small or no P3. Statistical analysis of phase required the use of circular statistical analysis and the development of a new form of topographic mapping, circular topography. The alpha phase at stimulus onset in single-trials with a large P3 was significantly different from that in single-trials with a small or no P3 (p =. 02).

Shallow-Water Flow past Isolated Topography. Part II: Transition to Vortex Shedding

Abstract The formation of Karman vortex streets is studied within the framework of single-layer shallow-water dynamics and in absence of surface friction and background rotation. In the first part of this study, steady numerical solutions for flow past circular topography were obtained by imposing a symmetry condition that essentially suppressed vortex shedding. In the second part, this symmetry condition is relaxed in order to study the transition into the vortex-shedding regime. This transition is due to an instability of the symmetric wake pattern. The most unstable global normal mode of this instability is derived by a numerical method. Most of the features of this mode can be understood in terms of the absolute instability theory. The mode is essentially barotropic and relies on a positive feedback between the perturbations located on the two shearlines on either side of the wake. The classical shear modes centered on a single shearline are, on the other hand, shown to be absolutely stable even thoug...