Ellipsoidal Shape Research Articles

The visible and thermal light curve of the large Kuiper belt object (50000) Quaoar

Recent stellar occultations have allowed accurate instantaneous size and apparent shape determinations of the large Kuiper belt object (50000) Quaoar and the detection of two rings with spatially variable optical depths. In this paper we present new visible range light curve data of Quaoar from the Kepler/K2 mission, and thermal light curves at 100 and 160 µm obtained with Herschel/PACS. The K2 data provide a single-peaked period of 8.88 h, very close to the previously determined 8.84 h, and it favours an asymmetric double-peaked light curve with a 17.76 h period. We clearly detected a thermal light curve with relative amplitudes of ~ 10% at 100 and at 160 µm. A detailed thermophysical modelling of the system shows that the measurements can be best fit with a triaxial ellipsoid shape, a volume-equivalent diameter of 1090 km, and axis ratios of a/b = 1.19 and b/c = 1.16. This shape matches the published occultation shape, as well as visual and thermal light curve data. The radiometric size uncertainty remains relatively large (±40 km) as the ring and satellite contributions to the system-integrated flux densities are unknown. In the less likely case of negligible ring or satellite contributions, Quaoar would have a size above 1100 km and a thermal inertia ≤ 10 J m−2K−1s−1/2. A large and dark Weywot in combination with a possible ring contribution would lead to a size below 1080 km in combination with a thermal inertia ≳10 J m−2K−1s−1/2, notably higher than that of smaller Kuiper belt objects with similar albedo and colours. We find that Quaoar’s density is in the range 1.67–1.77 g cm−3, significantly lower than previous estimates. This density value closely matches the relationship observed between the size and density of the largest Kuiper belt objects.

Abstract 173: Studying the interaction between macrophages and solid stress in novel models of the tumor immune microenvironment

Abstract Glioblastoma (GBM) is one of the most aggressive forms of cancer, resisting conventional and immune-based therapies and typically killing patients within two years of diagnosis. This is largely due to the immunosuppressive GBM tumor microenvironment (TME), mediated in large part by tumor-resident macrophages. Macrophages’ role as immune regulators, as well as their sheer quantity in brain tumors, makes them attractive therapeutic targets. The GBM TME also features mechanical abnormalities. As a tumor grows, it expands into the surrounding brain, generating compressive solid stress. Macrophages can contribute to up to half of tumor mass and are known to respond to mechanical cues, allowing them to both contribute to and respond to solid stress, but this relationship has not yet been explored experimentally. To isolate the contribution of macrophages on solid stress, we incorporated RAW264.7 murine macrophages into agarose gels with varying stiffnesses. Over time, spheroids form as the cells proliferate. Because cells cannot alter agarose, cell aggregates must generate stress as they grow and displace the surrounding gel matrix. The resulting agarose-embedded spheroids were stained with calcein AM to observe spheroid viability and morphology. Using confocal microscopy and image processing, we obtained the final spheroid geometry and imported it into COMSOL to model the solid stress resulting from spheroid formation. Our initial experiments show that macrophages have distinct growth patterns dependent on the stiffness of their surrounding gel. At larger sizes, the spheroids adopt an ellipsoid shape and generate a distinct stress field compared to spheroidal shapes. To stimulate the solid stress that macrophages experience within a growing mass, we applied a custom weight to macrophages grown on a porous membrane. This applies 0.15 kPa of compressive solid stress, corresponding to the stress measured in murine glioma models. After 24 hours of compression, macrophages upregulate expression of both nitric oxide synthase and arginase-1, canonical M1 and M2 markers, respectively. This indicates that compression causes a more complex phenotype than can be described by the traditional M1/M2 axis, something that has been observed in tumor-associated macrophages. We also found an apparent difference in the fluorescence lifetime of compressed and uncompressed macrophages, indicating that compression alters macrophage metabolism. Both the spheroid and compression culture models are unique in the context of macrophages. This work will elucidate key pathways involved in myeloid “immunomechanics” and inform strategies to target the innate immune system in cancers such as GBM, as well as other immunological diseases. Citation Format: Alice Burchett, Saeed Siri, Hao Chen, Scott Howard, Meenal Datta. Studying the interaction between macrophages and solid stress in novel models of the tumor immune microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 173.

RDDA method for characterization of photonic nanojets.

This paper presents a reduced discrete dipole approximation (RDDA) method as a flexible and powerful tool for computing the field distribution of photonic nanojets (PNJs) based on superposition of the induced dipole radiation fields with a low number of lattice points at the surface of microparticles. Microparticles with spherical and ellipsoidal shapes have been studied using the RDDA method to produce PNJs. The incident beam polarization and filling factor effects in the PNJs' shape and confinement strength have been characterized by quality factor Q. The best confined PNJs have been found in microellipsoids with a specific range of the shape parameter and filling factor values.

Shape-induced clusters of ellipsoids during triaxial compression: A multiscale analysis using LS-DEM

In this work, we numerically investigate the quasi-static shear behavior of ellipsoids under triaxial compression using the level set discrete element method (LS-DEM). Assemblies composed of ellipsoids with various aspect ratios are prepared at the densest states and then sheared to the critical state. Macroscopically, the stress and dilation behaviors are strongly affected by the particle shape, with the spheres having the least shear strength and dilatancy. At the particle scale, more ellipsoidal particles are more resistant to particle rotations and can effectively increase friction mobilizations.We identify the clusters in assemblies via the three-dimensional cluster labeling algorithm and then analyze the structural and mechanical properties of clusters. Based on our analysis, we find that the clusters exhibit the power-law decay in the cluster size distribution and have fractal structures. Upon shearing, the clusters tend to self-organize to gain mechanical stability, indicated by the increasing cluster stress ratio, and mainly support the deviatoric stresses in the assemblies. The mean cluster stress ratio is found to be linearly related to the macroscopic shear strength at the critical state, where more ellipsoidal shapes can gain higher cluster stress ratios, contributing to higher shear strength for the granular assembly. Microscopically, the cluster contributes more significantly to geometrical anisotropy terms while comparably to mechanical ones compared to the non-cluster.

Early Triassic (Griesbachian) spheroids in Beibei, Chongqing, Southwestern China: Characteristics, cause and implications for palaeo‐oceanic conditions

Following the latest Permian mass extinction (LPME), abundant unusual sedimentary features and fabrics were widely distributed in Early Triassic carbonate platforms. As a unique type of carbonate grain, spheroids from the Lower Triassic are infrequently reported, yet differ significantly from giant ooids and oncoids. Griesbachian micritic spheroids are well preserved in the Lower Triassic Feixianguan Formation at the Baimiaozi (BMZ) outcrop in Beibei, Chongqing, southwestern China. These spheroids (diameter: 3.9–10.8 mm) were in a marl layer interbedded with massive oolites. They were deposited in the wave troughs of ripple marks comprising micritic clots, sparry calcite, clay minerals, organic matter and pyrite. A microbial spheroid origin is implied based on the coccoidal microbes (coccoid‐like microspherules and bacterial clump‐like microspherules), numerous pyrite framboids (indications suggest the presence of many sulphate‐reducing bacteria and the high iron content in seawater can promote nitrogen‐fixing cyanobacteria proliferation) and microbial‐derived microspherules. The dark‐coloured matrix between the spheroids primarily included microcrystalline calcite, clay minerals, organic matter and metazoan fossils. The spherical and ellipsoidal shapes of the spheroids suggested rapid accretion and lithification. As a unique carbonate depositional mode, Greisbachian spheroids may have been recorded for a palaeo‐ocean with dysoxic and calcium carbonate supersaturation shortly after the LPME.

A Complex Interplay Between Pluton Emplacement, Tectonic Deformation, and Plate Kinematics in the Cretaceous Sierra Nevada Magmatic Arc, California

AbstractThe relation of plate kinematics to the structural record of arc plutons and their host rocks is complex and still not fully understood. We address this issue through a combination of field mapping, structural analysis, anisotropy of magnetic susceptibility analysis, and fabric modeling in the Late Cretaceous Tuolumne Intrusive Complex, Sierra Nevada, California. A pattern of anti‐clockwise rotation from ∼NNW–SSE to WNW–ESE steep foliations and change in fabric ellipsoid shape from oblate to prolate was revealed in successively emplaced Kuna Crest (∼95–92 Ma), Half Dome (∼92–89 Ma), and Cathedral Peak (∼89–84 Ma) granodiorites. The numerical model indicates that the Kuna Crest was emplaced in a transpressional setting with an angle of convergence α = 60–40°, whereas the Half Dome and Cathedral Peak required simultaneous vertical constriction overprinted by transpression with α = 35–15°. This transition, which occurred at ∼92 Ma, is accompanied by a shallowing of the lineation plunge observed also in other ∼88–84 Ma central Sierra Nevada plutons. Provided that the Cretaceous Sierra Nevada arc was constructed during overall dextral transpression, these transitions reflect significant changes in kinematics, where ∼107–92 Ma plutons were emplaced during pure shear‐dominated transpression, which was followed by a transition to wrench‐dominated transpression recorded in ∼92–84 Ma plutons. Such a transition in kinematics is explained as a result of progressively increasing obliquity of the relative convergence of the Farallon plate subducting beneath the North American continental margin, in agreement with most paleogeographic reconstructions.

First report of Irpex rosettiformis causing white root rot in avocado trees in Michoacán, México.

In México, avocado production is an important economic source. In the last season it generated $ 3. 27 billion USD of foreign currency in the country. Irpex spp. are wood decay fungi. In the period 2019-2022, in the state of Michoacán (19°13' N; 101°55' W), México, basidiomes of Irpex sp. were observed on the base of trunks and crowns of 5-years-old and older avocado (Persea americana) trees. The trees exhibited disease symptoms that included white root rot, leaf yellowing, small leaves, branch diebacks, generalized defoliation, apical flaccidity, abundant but small sun burnt fruits due to the lack of foliage, and after 2-4 years of first disease appearance, the infected trees died. In the place where fungus was established, abundant white and cottony mycelium was formed, which caused trees decay. The incidence of the disease in the sampled orchards was estimated to be 30% per ha with 350 - 400 trees, which was determined through a simple sampling design focused on trees with signs and symptoms of the disease due to the phytopathogen. Samples of infected tissue (roots and stems) and fungal basidiomes were collected from 90 trees (5-6 per orchard). The symptomatic avocado trees studied were randomly selected from 17 orchards. For the fungal macroscopic characterization, the synoptic keys described by Gilbertson and Ryvarden (1986) and by Largent (1973) were used. The samples showed typical structures corresponding to Irpex sp., including rosettes, annual basidiomes, a system of monomitic hyphae, and subglobose basidiospores. In vitro fungal isolation from basidiomes and infected tree tissues was done according to the protocol of Agrios (2004). The fungal strains were maintained on PDA at 28 °C. At 16 days of incubation the colonies were opaque, whitish with fluffy and corky mycelium. Microscopic analysis of the fungus showed typical yellowish spores, with an ellipsoid shape of 3-4 x 4-5.5 µm (50 accounted structures per isolate [N=19]) and basidia of 20-25 x 4.5-5.5 µm (n=20 basidiomes). For molecular characterization, two molecular markers were used, the internal transcribed spacer rDNA-ITS1 5.8 rDNA-ITS2 (ITS; White et al. 1990) and the large ribosomal subunit (LSU; Vilgalys and Hester 1990). The PCR reaction was performed as described by Martínez-González et al. (2017). The consensus sequences were compared with those deposited in the NCBI-GenBank, using the BLASTN 2.2.19 tool (Zhang et al. 2000), the samples showed 99% match with the species, Irpex rosettiformis. GenBank accession numbers of the submitted isolates are summarized in supplementary Table 4. To test Koch's postulates, 3-months old avocado plants grown in greenhouse conditions were inoculated (n = 10 per each isolate [N= 19]) on the roots with 3 g of I. rosettiformis mycelium. The experiment was done twice with 20 non-inoculated plants as control. After 67 days, basidiomes (50 x 70 x 1.5 mm in average) were observed where the disease incidence was >77%, with subsequent tree decline. The pathogen was re-isolated in vitro in PDA and its identity was confirmed by morphological characteristics of mycelium. This work shows that I. rosettiformis is not only a wood decay fungus, but also a phytopathogen, the causative agent of white root rot disease in P. americana var. drymifolia, cultivar 'Hass', which establishes a precedent for monitoring and preventing its proliferation to other regions in the American continent and the world where nursery avocado seedlings are exported.

Characterization of mRNA Lipid Nanoparticles by Electron Density Mapping Reconstruction: X-ray Scattering with Density from Solution Scattering (DENSS) Algorithm.

This study aimed to test the feasibility of using Small Angle X-ray Scattering (SAXS) coupled with Density from Solution Scattering (DENSS) algorithm to characterize the internal architecture of messenger RNA-containing lipid nanoparticles (mRNA-LNPs). The DENSS algorithm was employed to construct a three-dimensional model of average individual mRNA-LNP. The reconstructed models were cross validated with cryogenic transmission electron microscopy (cryo-TEM), and dynamic light scattering (DLS) to assess size, morphology, and internal structure. Cryo-TEM and DLS complemented SAXS, revealed a core-shell mRNA-LNP structure with electron-rich mRNA-rich region at the core, surrounded by lipids. The reconstructed model, utilizing the DENSS algorithm, effectively distinguishes mRNA and lipids via electron density mapping. Notably, DENSS accurately models the morphology of the mRNA-LNPs as an ellipsoidal shape with a "bleb" architecture or a two-compartment structure with contrasting electron densities, corresponding to mRNA-filled and empty lipid compartments, respectively. Finally, subtle changes in the LNP structure after three freeze-thaw cycles were detected by SAXS, demonstrating an increase in radius of gyration (Rg) associated with mRNA leakage. Analyzing SAXS profiles based on DENSS algorithm to yield a reconstructed electron density based three-dimensional model can be a useful physicochemical characterization method in the toolbox to study mRNA-LNPs and facilitate their development.

A Spherical Cap Model of Epidural Hematomas.

Background Epidural hematomas (EDHs), which have a characteristic biconvex shape, are a type of post-traumatic intracranial mass. EDHs and other types of intracranial hematomas are often diagnosed with computed tomography (CT). The volumes of EDHs are important in treatment decisions and prognosis. Their volumes are usually estimated on CT using the "ABC" method, which is based on the ellipsoid shape rather than their biconvex shape. Objective To simulate the biconvex shape, we modeled the geometry of EDHs with two spherical caps. We aim to provide simpler estimation of EDH volumes in clinical settings, and eventually recommend a threshold for surgical evacuation. Methods Applying the relationship between the sphere radius, spherical cap height, and base circle radius, we derived formulas for the shape of an EDH, relating its largest diameter and location to the other two diameters. We also estimated EDH volumes using the spherical cap volume and conventional ABC formulas and then constructed a lookup table accordingly. Results Validation of the model was performed using 14 CT image sets from previously reported patients with EDHs. Our geometric model demonstrated accurate predictions. Themodel also allows reducing the number of parameters to be measured in the ABC method from three to one, the hematoma length, showcasing its potential as a reliable tool for clinical decision-making. Based on our model, an EDH longer than 7 cm would occupy more than 30 mL of the intracranial volume. Conclusion The proposed model offers a streamlined approach to estimating EDH volumes, reducing the complexity of parameters required for clinical assessments. We recommend a length of 7 cm as a threshold for surgical evacuation of EDHs. This acceleration in decision-making is crucial for managing critically injured patients with traumatic brain injuries. Further validation across diverse patient populations will enhance the generalizability and utility of this geometric modeling approach in clinical settings.

Shape effect on solid melting in flowing liquid

Iceberg melting is a critical factor for climate change. However, the shape of an iceberg is an often neglected aspect of its melting process. Our study investigates the influence of different ice shapes and ambient flow velocities on melt rates by conducting direct numerical simulations of a simplified system of bluff body flow. Our study focuses on the ellipsoidal shape, with the aspect ratio as the control parameter. We found the shape plays a crucial role in the melting process, resulting in significant variations in the melt rate between different shapes. Without flow, the optimal shape for a minimal melt rate is the disk (two-dimensional) or sphere (three-dimensional), due to the minimal surface area. However, as the ambient flow velocity increases, the optimal shape changes with the aspect ratio. We find that ice with an elliptical shape (when the long axis is aligned with the flow direction) can melt up to 10 % slower than a circular shape when exposed to flowing water. Following the approach considered by Huang et al. (J. Fluid Mech., vol. 765, 2015, R3) for dissolving bodies, we provide a quantitative theoretical explanation for this optimal shape, based on the combined contributions from both surface-area effects and convective-heat-transfer effects. Our findings provide insight into the interplay between phase transitions and ambient flows, contributing to our understanding of the iceberg melting process and highlighting the need to consider the aspect-ratio effect in estimates of iceberg melt rates.

Morphology of Deciduous Canines in African Apes

The aim of this study was to determine the morphology and sexual dimorphism of deciduous canines in African great apes. The morphology of the deciduous canines of the chimpanzee and the gorilla was similar in both the male and the female. The occlusal view of the chimpanzee showed an ellipsoid shape in the maxilla and a more distorted quadrilateral shape in the mandible. The lingual view showed a pyramidal triangle in the maxilla and a distorted square in the mandible. Compared to chimpanzees, gorillas had a larger maxillary labiolingual diameter, a more elliptical shape, a higher crown height and more mesial grooves. The basal tubercles, spinous processes and distal accessory ridges observed in human primary canines were not observed in chimpanzees and gorillas. No significant sex differences were found for maxillary and mandibular primary canines in chimpanzees. However, in the maxilla, there were significant sex differences in gorillas for all variables except mesiodistal diameter. Compared to humans, chimpanzees were significantly larger for all variables except maxillary labiolingual diameter. On the other hand, the crown index was significantly larger in humans and the occlusal view was more rounded. The deciduous canines of chimpanzees and gorillas were similar in morphology to the permanent canines of females of both species. However, they differed significantly from the permanent canines of males.

DNA break clustering as a predictor of cell death across various radiation qualities: influence of cell size, cell asymmetry, and beam orientation

Abstract Cosmic radiation, composed of high charge and energy (HZE) particles, causes cellular DNA damage that can result in cell death or mutation that can evolve into cancer. In this work, a cell death model is applied to several cell lines exposed to HZE ions spanning a broad range of linear energy transfer (LET) values. We hypothesize that chromatin movement leads to the clustering of multiple double strand breaks (DSB) within one radiation-induced foci (RIF). The survival probability of a cell population is determined by averaging the survival probabilities of individual cells, which is function of the number of pairwise DSB interactions within RIF. The simulation code RITCARD was used to compute DSB. Two clustering approaches were applied to determine the number of RIF per cell. RITCARD outputs were combined with experimental data from four normal human cell lines to derive the model parameters and expand its predictions in response to ions with LET ranging from ~0.2 keV/μm to ~3000 keV/μm. Spherical and ellipsoidal nuclear shapes and two ion beam orientations were modeled to assess the impact of geometrical properties on cell death. The calculated average number of RIF per cell reproduces the saturation trend for high doses and high-LET values that is usually experimentally observed. The cell survival model generates the recognizable bell shape of LET dependence for the relative biological effectiveness (RBE). At low LET, smaller nuclei have lower survival due to increased DNA density and DSB clustering. At high LET, nuclei with a smaller irradiation area—either because of a smaller size or a change in beam orientation—have a higher survival rate due to a change in the distribution of DSB/RIF per cell. If confirmed experimentally, the geometric characteristics of cells would become a significant factor in predicting radiation-induced biological effects. Insight Box: High-charge and energy (HZE) ions are characterized by dense linear energy transfer (LET) that induce unique spatial distributions of DNA damage in cell nuclei that result in a greater biological effect than sparsely ionizing radiation like X-rays. HZE ions are a prominent component of galactic cosmic ray exposure during human spaceflight and specific ions are being used for radiotherapy. Here, we model DNA damage clustering at sub-micrometer scale to predict cell survival. The model is in good agreement with experimental data for a broad range of LET. Notably, the model indicates that nuclear geometry and ion beam orientation affect DNA damage clustering, which reveals their possible role in mediating cell radiosensitivity.

Crossover from attractive to repulsive induced interactions and bound states of two distinguishable Bose polarons

We study the impact of induced correlations and quasiparticle properties by immersing two distinguishable impurities in a harmonically trapped bosonic medium. It is found that when the impurities couple both either repulsively or attractively to their host, the latter mediates a two-body correlated behavior between them. In the reverse case, namely the impurities interact oppositely with the host, they feature anti-bunching. Monitoring the impurities relative distance and constructing an effective two-body model to be compared with the full many-body calculations, we are able to associate the induced (anti-) correlated behavior of the impurities with the presence of attractive (repulsive) induced interactions. Furthermore, we capture the formation of a bipolaron and a trimer state in the strongly attractive regime. The trimer refers to the correlated behavior of two impurities and a representative atom of the bosonic medium and it is characterized by an ellipsoidal shape of the three-body correlation function. Our results open the way for controlling polaron induced correlations and creating relevant bound states.

Dynamics of Seed Productivity of the Endemic Species Anemonastrum biarmiense (Juz.) Holub (Ranunculaceae) in the South Ural Reserve

Five-year dynamics of seed productivity of the high-mountain endemic species Anemonastrum biarmiense (Juz.) Holub in the territory of the South Ural Reserve is presented. The collection of seed material was carried out in three cenopopulations (Dunan-Sungan, Yusha and Naratash), two of which are associated with tall grass communities of the Polygonion krascheninnikovii Kashapov 1985 union, the third cenopopulation is part of the tundra-like communities of the spruce-birch crooked forest of the Calamagrostion arundinaceae (Luquet 1926) Oberdorfer 1957 union. A brief description of the weather conditions of the growing year is given with a graph of minimum temperatures from May to July 2015–2021, where the largest number of days with frost was noted for 2017 (9 days), and not noted at all for 2021. A description of the morphological heterogeneity is given. Seeds of A.biarmiense, while it was found that the seeds of plants are most often characterized by an ellipsoidal shape, less often an ellipsoidal one with a base narrowed into a stem. The spherical shape of the seeds is more common in forest cenopopulations, and the ellipsoidal shape is more common in meadow ones. Seeds with a wavy and even edge are observed equally often. The metric and quantitative parameters of A. biarmiense seed productivity in natural cenopopulations from 2015 to 2021 are given. Most of the metrics increase in 2016, 2018 and decrease in 2015, 2017 with worsening weather conditions. Among the quantitative indicators, the largest number of ovules and seeds per seedling, fl ower-bearing shoot and individual were found in the meadow cenopopulations of Yusha, Dunan-sungan of the forest belt, and in the Naratash CP of the subalpine belt, their number is reduced. Accordingly, a higher seed productivity coeffi cient was found in the open meadow communities of the forest belt, and a lower one in the crooked forest belt. Characterizing the weather conditions of the growing year, most of the maximum values were found in 2016, when the climatic conditions were the most favorable during the growing season. The minimum values of seed productivity indicators were noted in 2017 and 2021, characterized by the least favorable weather conditions throughout the growing season. The lowest variability of seed productivity traits was found for the length and width of the seed, the highest – for the weight of seeds and the number of unfulfilled seeds per seed, flowering shoot and plant. The amplitude of variability for all studied parameters of seed productivity varies in a wide range among the observed cenopopulations in the belt of spruce crooked forests on the ridge. Naratash, while in the narrowest range, variation of signs in the Yusha and Dunan-sungan CP was revealed.

Controlled mean dynamics of red blood cells by two orthogonal ultrasonic standing waves

A computational model is developed to study the time-averaged mean dynamics of red blood cells (RBCs) driven by the time-averaged mean stress generated by two phase-shifted orthogonal ultrasonic standing waves in a viscous fluid. The cell is modelled as an ellipsoidal viscoelastic membrane enclosing the viscous fluid cytoplasm, the motion of which is described by the inclination angle of the ellipsoidal cell shape and the phase angle of the potential membrane cycle. Based on the acoustic perturbation method, the acoustic field and acoustic streaming field are solved to obtain the time-averaged mean stress, and then the temporal evolution equations of the inclination and phase angles of the cell are determined considering the torque balance and energy conservation. At a small acoustic pressure amplitude, this model reproduces the experimentally observed features of cell motion in orthogonal standing waves: the transition from steady stationary orientation to unsteady tumbling with the increase of the phase difference between the two standing waves. By turning up the acoustic pressure amplitude above a critical value, it is further predicted that the previously observed motions can be accompanied by the membrane tank-treading rotation. Observations of these motions, combined with the present computational model, can help to evaluate the mechanical properties of RBC membranes in an automated and high-throughput manner by acoustic methods.

A DEM-CFD Approach for Predicting Pressure Drop Through Packed Bed of Crushed Rocks

Predicting the pressure drop over a packed bed of air-crushed rocks is a crucial parameter for a solar storage system to be economically viable. The selection of the blower and the estimation of the total capacity of the storage system are highly dependent on it. There are various parameters that influence the air flow through the bed, such as the shapes and sizes of the crushed rocks, which affect the packing density and particle arrangement. In this paper, the crushed rock was represented by an ellipsoidal shape with the same volume and aspect ratio as the average of randomly collected crushed rock samples to investigate the pressure drop through the packed bed. Simulation models were developed to assist in driving a pressure drop correlation as well as the effect of particles' orientation on pressure drop. For simulation, a Discrete Element Model (DEM) was used to generate the particles and Computational Fluid Dynamics (CFD) to simulate the flow over the particles. To validate the DEM/CFD models, experiments consisting of a packed bed of ellipsoidal particles and crushed rocks were developed. Consequently, an equation based on the porous media approach was proposed to predict the pressure drop, and the correlation was found to underestimate the pressure drop through the crushed rock by less than 20% in the horizontal flow.

Synthesis of ℋ∞ Control for Descriptor Hybrid Systems with Actuator Saturation

This paper addresses a mode-dependent state-feedback H∞ control for stochastic descriptor hybrid systems, considering both the absence and presence of actuator saturation. Firstly, the necessary and sufficient conditions for the stochastic admissibility criterion with H∞ performance γ of the closed-loop system are proposed. Given the proposed non-convex condition, the author reformulates it into linear matrix inequalities (LMIs). Then, to extend the result to the systems with actuator saturation, the actuator-saturated control input is expressed as a linear combination of a given state-feedback control input and a virtual control input that always remains under the saturation level. To verify this expression, the set invariant condition is also suggested by using the singular mode-dependent Lyapunov function candidate. Therefore, the conditions for the existence of both the mode-dependent state-feedback H∞ control and the ellipsoidal shape invariant sets are successfully derived in terms of LMIs. Two numerical examples demonstrate the effectiveness of the proposed method by solving optimization problems subject to the proposed LMIs that minimize H∞ performance γ and maximize the invariant set, respectively.

Age-related changes in the primary auditory cortex of newborn, adults and aging bottlenose dolphins (Tursiops truncatus) are located in the upper cortical layers.

The auditory system of dolphins and whales allows them to dive in dark waters, hunt for prey well below the limit of solar light absorption, and to communicate with their conspecific. These complex behaviors require specific and sufficient functional circuitry in the neocortex, and vicarious learning capacities. Dolphins are also precocious animals that can hold their breath and swim within minutes after birth. However, diving and hunting behaviors are likely not innate and need to be learned. Our hypothesis is that the organization of the auditory cortex of dolphins grows and mature not only in the early phases of life, but also in adults and aging individuals. These changes may be subtle and involve sub-populations of cells specificall linked to some circuits. In the primary auditory cortex of 11 bottlenose dolphins belonging to three age groups (calves, adults, and old animals), neuronal cell shapes were analyzed separately and by cortical layer using custom computer vision and multivariate statistical analysis, to determine potential minute morphological differences across these age groups. The results show definite changes in interneurons, characterized by round and ellipsoid shapes predominantly located in upper cortical layers. Notably, neonates interneurons exhibited a pattern of being closer together and smaller, developing into a more dispersed and diverse set of shapes in adulthood. This trend persisted in older animals, suggesting a continuous development of connections throughout the life of these marine animals. Our findings further support the proposition that thalamic input reach upper layers in cetaceans, at least within a cortical area critical for their survival. Moreover, our results indicate the likelihood of changes in cell populations occurring in adult animals, prompting the need for characterization.

New light on the Oughterard Granite: Connemara's S-Type granite, Ireland

Abstract: Most of the Connemara granites, including the Galway Granite batholith, have a clearly defined circular or ellipsoidal outcrop shape and are I-Type granites often with K-feldspar phenocrysts, whereas the Oughterard Granite (OG) forms numerous small intrusions scattered east-west over 40km with two larger linked bodies near Oughterard and is S-Type and aphyric. The only comprehensive mapping, mineralogical and chemical study of the OG was published over 50 years ago before the important 1974 recognition of the distinction of I- and S-Type granites was first made. New mapping of the southern Oughterard area with small OG intrusions is presented and many scattered published chemical and Rb, Sr, S and Pb isotopic studies integrated to confirm overall their individual conclusions that the peraluminous OG is of S-Type, being formed from melted Dalradian rocks as are the fluid-carried associated uneconomic mineral deposits. The OG is confined to the high sillimanite zone, mostly south of, and mainly later than, the 465-464Ma D4 Connemara Antiform, where a wide (>15km N-S) >70km E-W band of 469Ma gabbros and 467Ma quartz diorite gneisses intruded into already hot Dalradian rocks undergoing regional metamorphism. This generated the OG magmas by partial melting of pelites and semi-pelites. The upward intrusion of the OG magma was significantly delayed, as has been shown by precise dating in other granites elsewhere, to ∼464-461Ma during the late stages and mostly after D4 but before the country rocks had completely cooled. The OG intrusions as a whole probably form the second largest area of S-Type granite in Ireland, after the Leinster Granite.

Elucidating shape-mediated drug carrier mechanics of hematite nanomaterials for breast cancer therapeutics.

Metallic nanomaterials have gained significant attention in cancer therapy as potential nanocarriers due to their unique properties at the nanoscale. However, nanomaterials face several drawbacks, including biocompatibility, stability, and cellular uptake. Hematite (α-Fe2O3) nanoparticles are emerging as promising nano-carriers to reduce adverse outcomes of conventional chemotherapeutics. However, the shape-mediated drug carrier mechanics of hematite nanomaterials are not raveled. In this study, we tailored hematite nanoparticles in ellipsoidal (EHNP) and spherical (SHNP) shapes with excellent biocompatibility and efficient drug encapsulation and release. We elucidate that EHNP exhibits higher cellular uptake than SHNP. With effective cellular internalization, the cisplatin-loaded EHNP showed excellent cytotoxicity with an IC50 value of 200 nM compared to the cisplatin-loaded SHNP. The flow cytometry cell sorting (FACS) analysis showed a four-fold increase in cell death by arresting the cells at the G0/G1 and G1 phases for cis-EHNP compared to cis-SHNP. The results show that ellipsoidal-shaped hematite nanoparticles can act as attractive nanocarriers with improved therapeutic efficacy in cancer therapy.