Spherical Volume Research Articles

Extracting free energies from local composition fluctuations in solids: A frequency distribution analysis of simulated atom probe data obtained by TAPSim

The present work proposes a novel methodology to extract direct thermodynamic information, i.e. Gibbs free energies, from local composition fluctuations found in atom probe data based on statistical mechanics. The proof-of-concept is demonstrated with an exemplary simulated Cu–Ni alloy, which has first been equilibrated using Monte Carlo techniques with an embedded-atom method potential and subsequently field evaporated by TAPSim. It is shown that the variance of the frequency distribution of the local composition on the reconstructed data reveals a systematic dependence on the size of the chosen spherical (sub-) volume used for the evaluation, but nevertheless the extrapolation to an infinitely large volume unveils a unique link to the curvature of the Gibbs free energy. Given the composition range is explored at several points, the Gibbs excess free energy of mixing could be recovered in a CALPHAD-style parametrization. This methodology promises to improve the accuracy of thermodynamic information (e.g. miscibility gap, mixing/demixing tendencies, critical solution temperature) from direct atom probe measurements.

Inside Cover

The cover image created by Mr. Keon‐Woo Kim shows various methods to fabricate unconventional nanostructures including highly asymmetric lamellae, inverted cylinders, hexagon cylinders and gyroids, and spherical microdomains with larger volume of spheres. These methods are achieved by designing complex chain architectures of BCP. For example, star‐shaped and miktoarm BCPs, blending two BCPs, multiblock BCPs or introducing favorable interactions between block components. DOI: 10.1002/pol.20230292 image

Theoretical and experimental study on the radiative properties of Parachlorella kessleri: considering the effect of internal microstructure.

A microalgal cell model with multiple organelles considering both the irregular overall shape and internal microstructure was proposed. The radiative properties of Parachlorella kessleri during the normal phase, starch-rich phase, and lipid-rich phase were calculated by the discrete dipole approximation method in the visible wavelengths. The accuracy of the model is verified with experimental measurements. The results showed that the theoretical calculation of the established microalgal cell model is more accurate than those of the equal volume spheres, such as the homogeneous sphere and the coated sphere, with the errors of the scattering cross-section reduced by more than 10.7%. The calculated scattering phase function of the multi-component model is basically in good agreement with the experimental results. Compared to the normal growth phase, the lipid enrichment during the lipid-rich phase leads to a sharp increase in the scattering cross-section by three to four times, while the absorption cross-section remains stable. Remarkably, in the starch-rich phase, the abundant production of starch results in a reduction of two to three times in the absorption cross-section compared to the normal growth phase, while the scattering cross-section varies little. The results can provide basic data and theoretical support for the design and optimization of photobioreactors.

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.

Abstract WMP82: Peri-Hematomal Edema (PHE) Shape Features as Independent Predictors of the 3-month Outcome in Acute Supratentorial Intracerebral Hemorrhage (ICH)

Background: Perihematomal edema (PHE) is a marker of post-ICH secondary brain injury and a potential treatment target. However, different studies have reported equivocal results regarding the optimal metrics of PHE volume in relation to clinical outcomes - such as absolute, and relative baseline PHE volume, or the rate of PHE volume growth over the first 24- and 72-hours post-ICH. In this study, we examined the association of different PHE shape features at baseline and 24-hour with outcome at 3-month follow-up. Methods: We used the data from ATACH-2 trial. We manually segmented ICH and PHE on baseline and follow-up CTs, and extracted 14 shape features. We explored the association of baseline, follow-up, difference (baseline subtracted from follow-up) and temporal rate (difference divided by time gap) of PHE shape changes with 3-month mRS. We applied Spearman correlation to assess univariate associations, and multivariate stepwise regression to evaluate if PHE shape features independently predict outcome adjusting for age, sex, NIHSS, GCS, baseline ICH volume, and treatment. Results: 796 patients were included. Baseline PHE maximum diameters across various planes, main axes, volume, surface and sphericity correlated with 3-month mRS after adjusting for multiple comparisons. The 24-hour difference and temporal change rates of these features also had significant association with outcome - but not the 24-hour absolute values. In multivariate regression, baseline PHE shape sphericity (p=0.029) and voxel volume (p=0.026), alongside admission NIHSS (p< 0.001), ICH volume (p=0.002), and age (p<0.001) were independent predictors of favorable outcomes. Conclusion: Aside from metrics of volume, PHE sphericity at baseline is an independent prognostic factor, with less spheric (more irregular) shape associated with worse outcome. In addition, baseline PHE shape features - compared to changes over the first 24 hours post-ICH - had stronger prognostic associations.

Evaluation of blood supply and metabolism in tumor, axillary lymph node and normal breast tissue with F-18 FDG PET/CT in breast cancer: comparison with pathological prognostic factors

Background and purposePerfusion parameters obtained in F-18 FDG PET/CT performed for staging purposes in breast cancers may provide additional information about tumor biology as well as glucose metabolism. The aim of this study was to evaluate throughout F-18 FDG PET/CT the relationship between blood flow and glucose metabolism and histological parameters of the primary tumor, normal mammary gland, and axillary lymph nodes in breast cancer patients.Materials and methodsSixty six female patients (mean age 51 y ± 12,81) were prospectively included to this study. We performed dynamic blood flow (f) study that started with 296–444 MBq (8–12 mCi) F-18 FDG injection and lasted for 10 minutes, and glucose metabolism (m) imaging one hour later. On each frame, mean activity concentration (AC) values (Bq/mL) were recorded on a spherical volume of interest (VOI) having a volume of ~ 1 cm3 on the hottest voxel of primary tumor (T), across normal breast gland (NG) and ipsilaterally axillary lymph nodes (iLN). Correlations among PET parameters and estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (c-erbB2) and Ki67 index were analyzed.ResultsT volume (TV) ranged from 1.1 to 85.28 cm3 [median (IR): 6.44 (11.78)]. There were positive correlations between c-erbB2 and TACf and between c-erbB2 and iLNACf (p = 0.045, r = + 0.248; p = 0.050, r = + 0.242). In the ER positive (ERP) patients, TV and TACm were significantly lower than those of ER negative (ERN) (respectively p = 0.044 and p = 0.041). In patients with two positive Ki-67 indices, iLN-SUVmax was significantly higher than one-positive patients (p = 0.020). There was a negative correlation between NGACm and histological grade of tumor (p = 0.005, r = − 0.365).ConclusionsBreast cancer shows differences in progression, metastasis and survival due to its diversity in terms of molecular, biological and angiogenesis. High glucose metabolism in breast cancers is associated with tumor aggressiveness. Being able to examine tumor tissue characteristics such as blood flow and glucose metabolism with a single diagnostic technique and to reveal its relationship with histological parameters can provide a reliable pretherapeutic evaluation in breast cancers.

Rethinking nuclear shaping: insights from the nuclear drop model.

Changes in the nuclear shape caused by cellular shape changes are generally assumed to reflect an elastic deformation from a spherical nuclear shape. Recent evidence, however, suggests that the nuclear lamina, which forms the outer nuclear surface together with the nuclear envelope, possesses more area than that of a sphere of the same volume. This excess area manifests as folds/wrinkles in the nuclear surface in rounded cells and allows facile nuclear flattening during cell spreading without any changes in nuclear volume or surface area. When the lamina becomes smooth and taut, it is inextensible, and supports a surface tension. At this point, it is possible to mathematically calculate the limiting nuclear shape purely based on geometric considerations. In this paper, we provide a commentary on the "nuclear drop model" which seeks to integrate the above features. We outline its testable physical properties and explore its biological implications.

Formation of bijels stabilized by magnetic ellipsoidal particles in external magnetic fields.

Bicontinuous interfacially-jammed emulsion gels (bijels) are increasingly used as emulsion templates for the fabrication of functional porous materials including membranes, electrodes, and biomaterials. Control over the domain size and structure is highly desirable in these applications. For bijels stabilized by spherical particles, particle size and volume fraction are the main parameters that determine the emulsion structure. Here, we investigate the use of ellipsoidal magnetic particles and study the effect of external magnetic fields on the formation of bijels. Using hybrid Lattice Boltzmann-molecular dynamics simulations, we analyze the effect of the magnetic field on emulsion dynamics and the structural properties of the resulting bijel. We find that the formation of bijels remains robust in the presence of magnetic fields, and that the domain size and tortuosity become anisotropic when ellipsoidal particles are used. We show that the magnetic fields lead to orientational ordering of the particles which in turn leads to alignment of the interfaces. The orientational order facilitates enhanced packing of particles in the interface which leads to different jamming times in the directions parallel and perpendicular to the field. Our results highlight the potential of magnetic particles for fabrication and processing of emulsion systems with tunable properties.

Gravity of gluonic fluctuations and the value of the cosmological constant

We analyze the classical linear gravitational effect of idealized pion-like dynamical systems, consisting of light quarks connected by attractive gluonic material with a stress–energy in one or more dimensions. In one orbit of a system of total mass M, quarks of mass expand apart initially with , slow due to the gluonic attraction, reach a maximum size , then recollapse. We solve the linearized Einstein equations and derive the effect on freely falling bodies for two systems: a gluonic bubble model where uniform gluonic stress–energy fills a spherical volume bounded by a 2D surface comprising the quarks’ rest mass, and a gluonic string model where a thin string connects two pointlike quarks. The bubble model is shown to produce a secular mean outward residual velocity of test particles that lie within its orbit. It is shown that the mean gravitational repulsion of bubble-like virtual-pion vacuum fluctuations agrees with the measured value of the cosmological constant, for a bubble with a radius equal to about twice the pion de Broglie length. These results support the view that the gravity of standard QCD vacuum fluctuations is the main source of cosmic acceleration.

General Cultural Competence of a Future Teacher in a Changing World

The purpose of the study. The paper analyzes the content оf the concept of “general cultural competence of a future teacher” and its dialectical development in a changing world under the influence of various factors: the new technological order; the complexity and diversity of various social environments; the risks of environmental, energy and epidemic crises; the emergence of artificial intelligence and learning neural networks; and the large consequences of small (at first glance) events in public life. The authors of this paper identified the inseparable connection of the general cultural competence of a future teacher with the general culture of human society. The work culture (professional activity) of a teacher is understood as an intellectual, socially oriented creative activity in the field of education, which has a spiritual ground and value sense. Such professional activity includes imperatives of personal and professional development, learning new things, motivation to participate in the life and upbringing of the subjects of their work – students. The trend of pragmatism in the development of educational programs of higher education, underestimation of the humanistic function of pedagogical universities and the need to form longitudinal professional and life goals of graduates is actualized. Materials and methods. The study is based on the analysis of scientific publications in the field of competence-based, culturological and learner-centered approaches in pedagogy. The content of publications was compared, and the frequency of key terms in these publications was analyzed using the online service “Semantic text analysis online, seo text analysis”.The results of the study. The results prove that the phenomenon of culture arises in the process of human coevolution. In this study, the structure and content of culture is seen as a sphere with three poles (religion, art, science). In the process of historical increase in the volume of culture, these poles could have changed mutual distances, demonstrating a prevailing influence of each pole on the volume of the culture sphere. Furthermore, the series of categories of “cult – culture – general cultural competence of a future teacher” was analyzed. In the context of the competency-based approach, an analysis of the content of the concept “general cultural competence of a future teacher” is considered. It has been suggested that leadership competence can be considered as part of the general cultural competence of a future teacher, determining the ability to independently organize his or her own professional and life trajectory from the position of a leader, creating an atmosphere of cooperation in the pedagogical, design or research process. The leader's worldview is seen to be an integral part of the general culture of a person, being realized in the normative (regulatory) and evaluative (axiological) functions of the culture, as well as in the socialization function together with a continuous desire for self-improvement in the profession and life.Conclusion. The findings of the study demonstrate that teachers, as carriers and subjects of culture, need to develop their general cultural competence to navigate in and adapt to a changing world. The considered competences are crucial in the modern conditions and should be directly or indirectly introduced into the future Federal State Educational Standards of Higher Education in the Russian Federation.

Estimation of the Needed Regolith for Covering Lunar Habitat by Protective Layer

Abstract The article deals with estimation of the amount of regolith to be mined with respect to the preparation of lunar habitat. Estimation of the size of the pit is related to the overlay of regolith for habitat made of a composite concrete-like structure. The evaluation is based on the number of inhabitants, necessary floor area, and the considered structure that is made of three segments. The first segment is a linear vault with a half cylinder cross section ending with a half sphere on both sides of the vault. Elementary formulas for the computation of volume of cylinder and sphere are applied.

Passive shimming for the 9.4 T whole-body MRI superconducting magnet

A superconducting magnet with a warm-bore size of 800 mm and a center magnetic field of 9.4 T for the whole-body magnetic resonance imaging (MRI) system was developed in IEECAS, China. To achieve a highly homogeneous magnetic field over the 400 mm diameter of spherical volume (DSV), both active shimming and passive shimming techniques were employed. This paper mainly focuses on the implementation of passive shimming for the 9.4 T MRI magnet system. After four iterations, we were able to achieve peak-to-peak and root mean square field homogeneities over the DSV at 3.05 and 0.94 ppm, respectively. In addition, this paper analyzes the electromagnetic forces and system errors of passive shimming for ultra-high fields, providing valuable insights into MRI magnet engineering.

Study on the leakage morphology and temperature variations in the soil zone during large-scale buried CO2 pipeline leakage

In the CCUS technology chain, buried CO2 pipelines are inevitable under special terrain conditions. Due to the concealment and the complexity of the soil, they have a higher possibility of leakage. However, there is limited research on buried CO2 pipeline leakage processes. In this study, authors used existing industrial-scale pipelines as CO2 storage containers and constructed a large-scale buried CO2 pipeline experimental system. The leakage hole size and direction were considered to investigate the leakage morphology and temperature changes in the soil. The results showed that during the small-hole leakage, dry ice spheres were formed, which adhered to the pipeline. According to the change of temperature field, the dry ice spheres expanded towards weak areas in the soil, rather than strictly along the jet direction. The volume of dry ice spheres generated in the upward leakage process was the largest, while the volume was the smallest in the downward leakage process. Due to the soil resistance, the volume of dry ice spheres generated in the 3 mm leakage process was always greater than 9 times that of the 1 mm leakage process. The experimental results provide important references for optimizing leakage detection systems and conducting leakage risk assessments.

Energy dissipated by spherical nanoparticles debonding in nanocomposites under cryogenic and steady state conditions

In this paper, an analytical model was presented to estimate the influence of nanoparticles size and volume fraction on the debonding dissipation energy of nanoparticles/polymer nanocomposites in cryogenic temperature. A spherical representative volume element including a nanoparticle and a pure polymer phase was considered. It was assumed that the temperature is uniform within the whole RVE, i.e., a steady state temperature condition. Using the stress and displacement fields within the constituents of RVE, the dependence of the debonding dissipation energy on the nanoparticles size and volume fraction was obtained at a certain temperature. In addition to the analytical model, a finite element (FE) analysis using surface-based cohesive method was carried out to simulate the debonding process under cryogenic and steady state conditions. It was observed that the nanoparticles size has a significant effect on the energy dissipated by debonding. Moreover, the results manifested that the nanoparticles volume fraction affects the dissipation energy of debonding in nanocomposites reinforced by larger nanoparticles at cryogenic temperature. A good agreement was also found between the FE analysis results and the closed-form solution data. The conclusions obtained by this closed-form solution can be useful as a trigger for the other energy dissipation mechanisms occurred in the nanocomposites reinforced by nanofillers such as silica, alumina, titania, etc.

Interaction of elastic waves in solids with quadratic and cubic nonlinearity.

This article investigates the interactions of two-plane waves in weakly nonlinear elastic solids containing quadratic and cubic nonlinearity. The analytical solutions for generated combined harmonic waves are derived using the Green's function approach applied to a generated system of quasi-linear equations of motion. Wave mixing solutions are obtained and include shape functions that permit closed-form solutions for a variety of interaction geometries. An explicit example is highlighted for a spherical interaction volume assuming isotropic elastic constants. Several parameters of the generated field after mixing are analyzed including resonant and nonresonant mixing, the role of interaction angle, and the frequencies of the two incident waves. Wave mixing offers the potential for sensing localized elastic nonlinearity and the present model can be used to help design experimental configurations.

Semi-Fragile Reversible Watermarking for 3D Models Using Spherical Crown Volume Division

Aiming at the large distortion and low tampering localization accuracy of the existing semi-fragile reversible watermarking for 3D mesh models, a novel semi-fragile reversible watermarking for 3D models using spherical crown volume division is proposed. The crown volume of a sphere is divided to reduce the embedding distortion. The possible geometric and topological transformations are separately considered in the watermark generation, and the vertices of the one-ring neighbourhood are grouped to improve the tampering localization accuracy. Experimental results show that the proposed scheme can achieve better localization accuracy and lower embedding distortion than some state-of-the-art algorithms. It has good potential for the applications in integrity authentication for 3D mesh models.

Modeling of porous-hardened concrete by rheological-dynamical analogy

PurposeThe purpose of this paper is to describe various aspects of the visco-elastoplastic (VEP) behavior of porous-hardened concrete samples in relation to standard tests.Design/methodology/approachThe problem is formulated on the basis of the rheological-dynamic analogy (RDA). In this study, changes in creep coefficient, Poisson's ratio, damage variables, modulus of elasticity, strength and angle of internal friction as a function of porosity are defined by P and S wave velocities. The RDA model provides a description of the degradation process of material properties from their peak state to their ultimate values using void volume fraction (VVF).FindingsCompared to numerous versions of acoustic emission tracking developed to analyze the behavior of total wave propagation in inhomogeneous media with density variations, the proposed model is comprehensive in interpretation and consistent with physical understanding. The comparison of the damage variables with the theoretical variables under the assumption of spherical voids in the spherical representative volume element (RVE) shows a satisfactory agreement of the results for all analyzed samples if the maximum porosities are used for comparison.Originality/valueThe paper presents a new mathematical-physical method for examining the effect of porosity on the characteristics of hardened concrete. Porosity is essentially related to density variations. Therefore, it was logical to define the limit values of porosity using the strain energy density.

Changing the geometry of polymer spherical orbital implants

BACKGROUND: Over the past decades, various polymer implants have been actively used in the rehabilitation of patients with anophthalmos to form a volumetric support stump and improve the results of cosmetic prosthetics.
 AIM: To assess clinical symptoms and features of the X-ray picture in patients with anophthalmos after implantation of polymeric spherical endoprostheses with a modified geometry.
 MATERIALS AND METHODS: The study is based on the analysis of 30 patients with anophthalmos after enucleations (23) and eviscerations (7) performed using various methods of procedure and insertion into tissues of an implant made of domestic polytetrafluoroethylene. All patients underwent a multispiral computed tomography (MSCT) of the eye sockets according to the same algorithm.
 RESULTS: On the basis of the performed studies, the fact of making a change in the geometry of the implanted spherical implants was revealed, while the parameters of the modified part of the spheres were different and ranged from 14 to 18 mm of final diameters with the initial diameters of the spheres ranging from 18 to 20 mm. A decrease in the volume of spheres with modified geometry from 0.114 to 0.651 cm3 was revealed with initial diameters ranging from 18 to 20 mm.
 CONCLUSIONS: Changes in the geometry of the orbital spheres do not improve the results of cosmetic prosthetics in patients, increase the percentage of implant exposure at different times after surgery, and increase the manifestations of anophthalmic syndrome.

Development of a Single-Neurosphere Culture to Assess Radiation Toxicity and Pre-Clinical Cancer Combination Therapy Safety.

Radiation therapy (RT) is a crucial treatment modality for central nervous system (CNS) tumors but toxicity to healthy CNS tissues remains a challenge. Additionally, environmental exposure to radiation during nuclear catastrophes or space travel presents a risk of CNS toxicity. However, the underlying mechanisms of radiation-induced CNS toxicity are not fully understood. Neural progenitor cells (NPCs) are highly radiosensitive, resulting in decreased neurogenesis in the hippocampus. This study aimed to characterize a novel platform utilizing rat NPCs cultured as 3D neurospheres (NSps) to screen the safety and efficacy of experimental drugs with and without radiation exposure. The effect of radiation on NSp growth and differentiation was assessed by measuring sphere volume and the expression of neuronal differentiation markers Nestin and GFAP and proliferation marker Ki67. Radiation exposure inhibited NSp growth, decreased proliferation, and increased GFAP expression, indicating astrocytic differentiation. RNA sequencing analysis supported these findings, showing upregulation of Notch, BMP2/4, S100b, and GFAP gene expression during astrogenesis. By recapitulating radiation-induced toxicity and astrocytic differentiation, this single-NSp culture system provides a high-throughput preclinical model for assessing the effects of various radiation modalities and evaluates the safety and efficacy of potential therapeutic interventions in combination with radiation.

A Novel Approach to Support Quality Assurance (QA) of Intensity Modulated Neutron Therapy (IMNT)

Neutron therapy is a form of high linear energy transfer (LET) radiation treatment shown to be beneficial for the treatment of locally advanced head and neck cancers (HNC) resistant to low LET x-ray and proton therapy treatments. The Clinical Neutron Therapy System (CNTS) at our institution has been in clinical operation for over 35 years, and over 3,400 patients have been treated using 3D conformal neutron radiation therapy. In October of 2022, the clinical commissioning of IMNT was completed and the first-ever patient was treated. A novel patient specific quality assurance (PSQA) program has been developed to support IMNT. We present an analysis of our early experiences and PSQA findings for the first 16+ patients treated with IMNT. Our pre-treatment IMNT PSQA program includes (1) ionization chamber measurements, (2) a log-file analysis of treatment delivery, and (3) a γ-analysis of the expected and measured doses (fluences) from a novel positron emission portal imaging system based on 12C(n,2n)11C reactions. Patient setup is confirmed on a daily basis with kV portal imaging. We use a modulation factor (MF), defined as the total number of monitor units (MU)/prescribed dose (cGy) per fraction, to identify and help anticipate IMNT plans that may fail our PSQA program. We have found that IMNT treatments for large, irregularly shaped treatment volumes (e.g., chest wall or head and neck cancers that require treatment of nodes in the lower neck) are more likely to fail PSQA when the MF exceeds 3 MU/cGy. For smaller, more spherical treatment volumes (e.g., base of tongue cancers), plans with a MF up to 3.5 MU/cGy pass our PSQA criteria. Re-optimized plans subsequently passed PSQA with insignificant or no change in tumor coverage and organ-at-risk (OAR) dose. Re-optimized plans also reduced the total number of MU and number of segments, which has the added benefit of decreasing the overall treatment time and patient time on the table. About 10% of early IMNT patients have required plan re-optimization. Our pre-treatment clinical PSQA program and workflow provides useful information to guide IMNT treatment planning and delivery, and helps ensure the safe and accurate delivery of IMNT. Our early experiences suggest IMNT plans with smaller MF values are more likely to pass PSQA than plans with larger values of the MF.