Local Volume Research Articles

Drag model of finite-sized particle in turbulent wall-bound flow over sediment bed

Drag force acting on a particle is vital for the accurate simulation of turbulent multiphase flows, but the robust drag model is still an open issue. Fully resolved direct numerical simulation (DNS) with an immersed boundary method is performed to investigate the drag force on saltating particles in wall turbulence over a sediment bed. Results show that, for saltating particles, the drag force along the particle trajectories cannot be estimated accurately by traditional drag models originally developed for an isolated particle that depends on the particle-wall separation distance or local volume fraction in addition to the particle Reynolds number. The errors between the models and DNS are especially clear during the descending phase of the particles. Through simple theoretical analysis and DNS data fitting, we present a corrected factor using the classical, particle Reynolds number dependent drag force model as the benchmark model. The new drag model, which takes the particle vertical velocity into account, can reasonably predict the mean drag force obtained by DNS along a particle trajectory.

Spectral Energy Distributions for 258 Local Volume Galaxies

We present model spectral energy distribution (SED) fits to ultraviolet/optical/infrared observations for the 258 nearby galaxies in the Local Volume Legacy survey, a sample dominated by lower-luminosity dwarf irregular systems. The data for each galaxy include up to 26 spatially-integrated broadband and narrowband fluxes from the Galaxy Evolution Explorer, Spitzer Space Telescope, and Infrared Astronomical Satellite space-based platforms, and from the Sloan Digital Sky Survey, Two Micron All Sky Survey, and other ground-based efforts. The CIGALE SED fitting package is employed using a delayed star-formation history with an optional late burst or quenching episode to constrain 11 different free parameters that characterize the properties of each galaxy’s stellar and dust emission, with the overriding constraint that the ultraviolet/optical emission absorbed by interstellar dust grains is emitted in equal energy portions at infrared wavelengths. The main results are: (i) 94% of the SED fits yield reduced χ 2 values less than 3; (ii) the modeled stellar masses agree with those derived from 3.6 μm-based measures with a scatter of 0.07 dex; (iii) for a typical galaxy in the sample the SED-derived star-formation rate averaged over the past 100 Myr is about 88% of the value derived from standard hybrid indicators on similar timescales; and (iv) there is a statistically significant inverse relation between the stellar mass fraction appearing in the late burst and the total stellar mass. These results build upon prior SED modeling efforts in the local volume and lay the groundwork for future studies of more distant low-metallicity galaxies with JWST.

Comparison of Craniocaudal Spread of Lumbar Erector Spinae Plane Block With Two Volumes of Local Anesthetics

BACKGROUND: The erector spinae plane block (ESPB) is a less invasive, safer, and technically easier procedure compared to the conventional neuraxial technique. Although the ESPB is a favored and easy technique compared to neuraxial block, there is no study with a large number of patients describing the exact spread level of injected local anesthetics. OBJECTIVES: The purpose of this study was to identify ESPB spread in the craniocaudal direction and the incidence of spread into the epidural space, psoas muscle, and intravascular system. STUDY DESIGN: Prospective design. SETTING: A tertiary university hospital, pain clinic. METHODS: Right- or left-sided ESPBs (170 at L4) with fluoroscopy subsequent to ultrasound guidance due to acute or subacute low back pain were included. In this study, 10 mL (ESPB 10 mL group, contrast medium 5 mL) or 20 mL (ESPB 20 mL group, contrast medium 7 mL) of a local anesthetic mixture was injected. After confirming a successful interfascial plane spreading under ultrasound guidance, the remaining local anesthetic was injected under fluoroscopic guidance. The spread level of ESPB in the craniocaudal direction and the occurrence of injectate into the epidural space or psoas muscle was assessed using the saved fluoroscopic images. These images were compared between the ESPB 10 mL and ESPB 20 mL groups. Also, the presence or absence of intravascular injection during ESPB was assessed and compared between the ESPB 10 mL and ESPB 20 mL groups. RESULTS: The ESPB 20 mL group had a more extensive caudal distribution of contrast medium than the ESPB 10 mL group. Also, the total number of lumbar vertebral segments was significantly higher in the ESPB 20 mL group than that of the ESPB 10 mL group (1.7 ± 0.4 vs 2.1 ± 0.4, P < 0.001). Among all injections performed in this study, epidural, psoas muscle, and intravascular injections occurred in 2.9%, 5.9%, and 12.9%, respectively. LIMITATIONS: Only the craniocaudal direction was evaluated without evaluating the spread pattern in the medial to lateral direction. CONCLUSION: The ESPB 20 mL group showed a more extensive distribution of contrast medium than that of the ESPB 10 mL group. Inadvertent injections into the epidural space, psoas muscle, and intravascular system were observed. Among them, intravascular system injections were found to be the most common (12.9%). KEY WORDS: Erector spinae plane block, spread level, psoas muscle, intravascular injection

Study of Injector Geometry and Parcel Injection Location on Spray Simulation of the Engine Combustion Network Spray G Injector

Abstract Parcel-based simulations are the most common method to simulate fuel sprays, especially for reacting conditions, due to their lower computational cost compared to more highly resolved simulations. It is important, however, to understand how spray boundary conditions are used to initialize the parcels that represent the atomizing fluid affect downstream conditions and overall simulation performance. Traditionally, when parcel simulations are used, the injector tip geometry is either significantly simplified or removed altogether due to resolution limits. Recent advances in computational power and numerical methods, however, have made it possible to resolve flow through these features. Previous work has shown some potential effects of even simple injector tip geometries, and this study investigates the effect of very detailed nozzle geometries on parcel-based simulations that have typically ignored these details. Four different parameters were investigated: whether a simulation includes a detailed injector tip geometry or a flat surface; whether parcels are initialized at the counterbore exit, which is more common, or at the nozzle exit; the use of an experimentally derived rate of injection or one-way coupling with a separate internal nozzle volume of fluid (VOF) simulation; the use of nominal or measured injector geometry. Simulations were compared using both global penetrations as well as local data near the injector. Spray penetration and other global measures showed limited sensitivity to boundary conditions/initialization procedure, but local data such as the local liquid volume fraction showed greater variation between the conditions, which may have an impact on mixing and combustion predictions in engine applications.

GHz ultrasonic sensor for ionic content with high sensitivity and localization

Sensing the ionic content of a solution at high spatial and temporal resolution and sensitivity is a challenge in nanosensing. This paper describes a comprehensive investigation of the possibility of GHz ultrasound acoustic impedance sensors to sense the content of an ionic aqueous medium. At the 1.55GHz ultrasonic frequency used in this study, the micron-scale wavelength and the decay lengths in liquid result in a highly localized sense volume with the added potential for high temporal resolution and sensitivity. The amplitude of the back reflected pulse is related to the acoustic impedance of the medium and a function of ionic species concentration of the KCl, NaCl, and CaCl2 solutions used in this study. A concentration sensitivity as high as 1mM and concentration detection range of 0 to 3M was achieved. These bulk acoustic wave pulse-echo acoustic impedance sensors can also be used to record dynamic ionic flux.

Alterations of brain gray matter volume in children with obstructive sleep apnea.

Obstructive sleep apnea (OSA) seriously affects the children's cognitive functions, but the neuroimaging mechanism of cognitive impairment is still unclear. The purpose of our study was to explore the difference in brain local gray matter volume (GMV) between children with OSA and non-OSA, and the correlation between the difference regions of brain gray matter volume and cognitive, the severity of OSA. Eighty-three children aged 8-13 years were recruited in our study, 52 children were diagnosed as OSA by polysomnography, and 31 as the non-OSA. All the subjects were underwent high-resolution 3-dimensional T1-weighted magnetic resonance images. The voxel-based morphometry (VBM) was be used to analyse the local GMV. The Das-Naglieri cognitive assessment system (DN: CAS) was used to assess the subjects' cognitive. The difference of local GMV between the two groups was analyzed by two-sample T-test. The PSG variables and the scores of DN: CAS between the OSA group and non-OSA group were compared by independent samples t-tests. Pearson correlation was used to calculate the association between the difference areas of gray matter volumes in brain and DN: CAS scores, obstructive apnea/hypopnea index (OAHI, an index of the severity of OSA). The gray matter volume of the right Middle Frontal Gyrus (MFG_R) in OSA children were larger than the non-OSA children, and the OSA children had lower scores of the Word Series in DN: CAS. There was negative correlation between the scores of Expressive Attention in DN: CAS and the gray matter volume of the right middle frontal gyrus, and it was no significantly correlation between OAHI and the gray matter volume of the right middle frontal gyrus. Our results suggest that the development of gray matter volume in frontal cortex, which associated with attention, were sensitive to the effects of OSA, provides neuroimaging evidence for cognitive impairment in children with OSA.

Permeability and fabric compaction in forming of fiber metal laminates

Significant fluid–structure interaction is present in fiber metal laminate forming with a low viscous matrix. A modular, process-inspired test setup is presented for one-dimensional saturated and unsaturated infiltration experiments for fiber metal laminates. Permeability measurements for different fabric orientations, fabric layers, and fiber volume contents show low scatter and good repeatability for fiber volume contents up to 65%. Fiber metal laminate specimens were formed by exchanging the mid-segment of the test setup with a punch and die. The stiffness differences between metal and fabric lead to remarkably high compactions in the bending radii, significantly reducing the flow during infiltration. Contrary to resin transfer molding processes, no formation of resin-rich zones along bending edges occurs due to the high normal pressures from metal forming. A numerical forming simulation was developed to predict the local fiber volume content. Comparing the experimental results with the numerical simulation shows that the high fiber volume content in the radii almost exclusively impacts the overall permeability. Implications for fiber metal laminate processing and modeling are outlined.

Graded dosage of local anesthetic for spinal anesthesia during orthopedic and trauma surgeries on the lower extremities

Background. The development of a clear algorithm of a local anesthetic dosage for spinal anesthesia during surgeries on the lower extremities is an urgent issue, even after a century of using this method of analgesia. The aim of our study is to improve the efficiency and safety of spinal anesthesia during lower extremity surgery in orthopedic and trauma patients by developing a local anesthetic dosage algorithm. Materials and methods. The conducted study is based on the analysis of the bilateral spinal anesthesia methods in 75 patients with degree I–II ASA operational risk during orthopedic and trauma surgeries on the lower extremities who were divided into 3 study groups. Spinal anesthesia was performed using 0.5% bupivacaine, with the anesthetic dosage algorithm developed according to the patients’ height (group III) and the standard recommended dosage (group I, patients of short height, and group II, patients’ height > 180 cm). Results. When studying the hemodynamic indicators, the heart rate before surgery was as follows: in the first group, 73 ± 8 bpm, in the second group, 78 ± 6 bpm, in the third group, 79.32 ± 14.47 bpm. Thirty minutes after the injection of the anesthetic, the heart rate in the group 1 was 68 ± 5 bpm, and three hours after, it was 71 ± 9 bpm. In the group 2, the heart rate of patients 30 minutes after the injection of the anesthetic was 79 ± 7 bpm, three hours after, it was 84 ± 9 bpm. In the group 3, the heart rate of patients 30 minutes after the administration of the anesthetic was 71.56 ± 14.14 bpm, three hours after the injection, it was 71.280 ± 9.002 bpm. Data on systolic blood pressure before surgery was started were as follows: in the first group, 139.6 ± 12.3 mmHg, in the second group, 136.0 ± 9.6 mmHg, in the third group, 138.40 ± 16.18 mmHg. During the surgical intervention, blood pressure indicators in the group 1 were: 30 minutes after the introduction of the anesthetic — 113.0 ± 7.1 mmHg, 3 hours after — 122 ± 14 mmHg; in the second group: 30 minutes after the injection of the anesthetic — 138.0 ± 10.2 mmHg, 3 hours after — 141.0 ± 12.5 mmHg; in the third group: 30 minutes after the administration of the anesthetic — 102.48 ± 13.47 mmHg, 3 hours after the introduction — 118.2 ± 10.0 mmHg. The average duration of the sensory block in the group 1 was 182.5 ± 17.2 min, of the motor block — 130.0 ± 24.8 min; in patients of the group 2, the sensory block lasted 70.6 ± 13.1 min, and the motor block 23.3 ± 6.7 min; in the group 3, the duration of sensory block was 252.20 ± 74.32 min and of the motor block — 198.2 ± 59.0 min. Conclusions. 1. The use of small doses of hyperbaric bupivacaine does not affect hemodynamic parameters but reduces the quality and duration of anesthesia in tall patients. 2. The frequency of complications during spinal anesthesia does not increase with an increase in the volume of local anesthetic in tall patients. 3. Selection of graded dose allows for more predictable and qualitative application of spinal anesthesia during orthopedic and trauma surgeries.

FINITE ELEMENT BIOMECHANICAL MODELING OF PAROTID GLAND MORPHING IN PATIENTS UNDERGOING RADIOTHERAPY FOR HEAD AND NECK TUMORS

Patients treated with radiation therapy (RT) for head and neck cancer are exposed during the course of several weeks of treatment (6–7 weeks) to several physiological processes that can induce inter-fraction deformation of the parotid salivary glands (PGs). Gland morphing tends to make them move towards the high dose region of the dose distribution. As a consequence, parotids may be irradiated more than initially planned, leading to increased toxicity. We implemented a biomechanical model of the parotid morphing process that can serve as the basis to optimize adaptive RT protocols, leading to further reductions of dose to these structures. Raystation[Formula: see text] hybrid deformation algorithms and 3DSlicer[Formula: see text] tools were employed to obtain a mesh representation of PG anatomy and deformation from CT-series of eight patients treated with highly modulated radiotherapy (Tomotherapy[Formula: see text]). The biomechanical model was computationally implemented with the finite element software COMSOL[Formula: see text] multiphysics. Gland tissue was modeled as a linear elastic material with a Poisson ratio of 0.49 and a density value of 1 g/cm3. A radial force field was introduced to mimic parotid shrinkage due to radiation exposure. Fixed constraints were placed taking into account the anatomical barrier effect of parotid-surrounding structures (mandible) during the shrinkage process. The implemented biomechanical model was able to predict PG morphing with a mean volume difference of 1.36% [0.9–2.0] % between real and modeled deformed anatomy for the first half of treatment and 1.5% [0.8–2.1]% for the second half of treatment. Prediction of geometric overlap of observed versus simulated geometry as quantified using DICE was acceptable for the first half of the treatment but still unsatisfactory for the second half. Adding model components taking into account other elements that define PG morphing (facial geometry changes due to general weight loss and — in patients with significant macroscopic tumor load - local tumor volume loss) may accurately predict parotid morphing and thus permit further optimization of frequency and timing of off-line ART protocols in patients undergoing radiotherapy for head and neck cancer. This may result in a further reduction of treatment toxicity and these approaches are becoming even more important as the use of particle therapy with its increased dosimetric sensitivity towards geometric changes of the patient is slowly increasing.

Automated Placement of Scan and Pre-Scan Volumes for Breast MRI Using a Convolutional Neural Network.

Graphically prescribed patient-specific imaging volumes and local pre-scan volumes are routinely placed by MRI technologists to optimize image quality. However, manual placement of these volumes by MR technologists is time-consuming, tedious, and subject to intra- and inter-operator variability. Resolving these bottlenecks is critical with the rise in abbreviated breast MRI exams for screening purposes. This work proposes an automated approach for the placement of scan and pre-scan volumes for breast MRI. Anatomic 3-plane scout image series and associated scan volumes were retrospectively collected from 333 clinical breast exams acquired on 10 individual MRI scanners. Bilateral pre-scan volumes were also generated and reviewed in consensus by three MR physicists. A deep convolutional neural network was trained to predict both the scan and pre-scan volumes from the 3-plane scout images. The agreement between the network-predicted volumes and the clinical scan volumes or physicist-placed pre-scan volumes was evaluated using the intersection over union, the absolute distance between volume centers, and the difference in volume sizes. The scan volume model achieved a median 3D intersection over union of 0.69. The median error in scan volume location was 2.7 cm and the median size error was 2%. The median 3D intersection over union for the pre-scan placement was 0.68 with no significant difference in mean value between the left and right pre-scan volumes. The median error in the pre-scan volume location was 1.3 cm and the median size error was -2%. The average estimated uncertainty in positioning or volume size for both models ranged from 0.2 to 3.4 cm. Overall, this work demonstrates the feasibility of an automated approach for the placement of scan and pre-scan volumes based on a neural network model.

Particle trapping by charged spherical cavity and its effect on ions adsorption, mean electric potential, and EDL capacitance curve

A model has been presented to investigate the electric double layer at the wall of the spherical cavity with trapped charged mobile particle. The modified Fundamental Measure Theory has been employed to study the role of the trapped particle on the amount of net ion charge and electric double layer capacitance. Our results indicate that, in the presence of the mobile particle in somerange of low electric potentials, total net ion charges into the cavity and therefore EDL capacitance increase if the charges on the mobile particle and the cavity are of the opposite sign. This range decreases with increasing bulk electrolyte concentration and decreasing the cavity curvature. At high electric potentials the role of the excluded volume due to the particle leads to a decrease in the net ion charges. The behavior of the mean electric potential, which has been explained by the local volume charge density, is significantly influenced by the position of the particle intothe cavity, which is determined by its charge and size. Finally, the ions adsorption into the cavity at different bulk concentrations has been investigated to predict the amount of ions transfer from the cavity wall.

Numerical investigation of bed-to-tube heat transfer in a shallow fluidized bed containing mixed-size particles

Mixed-size particles with low processing cost have great potential to act as the absorbing media in the next-generation concentrated solar power plants. However, the research on the heat transfer from the particles to heated surfaces in gas–solid fluidized beds is limited. In this paper, the bed-to-tube heat transfer coefficient (HTC) in a shallow fluidized bed with immersed tubes is determined numerically. The Eulerian–Eulerian approach that incorporated the kinetic theory of granular flow has been implemented in a two-dimensional model. The distribution of the local HTC around the tube is investigated for various particle systems. The results show that the HTC reaches a maximum at the upper right (45°) and upper left (135°) of the tube, respectively, indicating a strong relation between the local HTC and solid volume fraction (SVF). The average HTC increases as the mean particle size gets smaller. For monosized particles, the HTC increases from 925 W/(m2·K) to 3033 W/(m2·K) as the particle size decreases from 300 to 100 µm. For binary particles, the growth in the HTC is nonlinear, with an increase in growth rate being observed as the small-size component becomes dominant. For mixed-size particles with the same mean size, a higher HTC can be achieved by enlarging the size difference between the components. A modified correlation for predicting the bed-to-tube HTC is established. Besides, the impacts of gas velocity and temperature, and heat radiation on the bed-to-tube HTC are discussed. It is found that an optimal gas velocity exists to maximize the average HTC and SVF simultaneously, while the gas temperature has a minor contribution. Due to the small heat transfer temperature difference, the effect of thermal radiation on the HTC can be neglected even though the bed temperature reaches 800 °C.

Formation of globular clusters in dwarf galaxies of the Local Group

ABSTRACT The existence of globular clusters (GCs) in a few satellite galaxies, and their absence in majority of dwarf galaxies, present a challenge for models attempting to understand the origins of GCs. In addition to GC presence appearing stochastic and difficult to describe with average trends, in the smallest satellite galaxies GCs contribute a substantial fraction of total stellar mass. We investigate the stochasticity and number of GCs in dwarf galaxies using an updated version of our model that links the formation of GCs to the growth of the host galaxy mass. We find that more than 50 per cent of dwarf galaxies with stellar mass $M_{\star }\lesssim 2\times 10^7\, \mathrm{M}_\odot$ do not host GCs, whereas dwarfs with $M_{\star }\sim 10^8\, \mathrm{M}_\odot$ almost always contain some GCs, with a median number ∼10 at z = 0. These predictions are in agreement with the observations of the Local Volume dwarfs. We also confirm the near-linear GC system mass–halo mass relation down to $M_{\mathrm{h}}\simeq 10^8\, \mathrm{M}_\odot$ under the assumption that GC formation and evolution in galaxies of all mass can be described by the same physical model. A detailed case study of two model dwarfs that resemble the Fornax dwarf spheroidal galaxy shows that observational samples can be notably biased by incompleteness below detection limit and at large radii.

Small angle approximation for the lidar return from clouds and fogs

The paper is aimed at the inter-comparison of the small angle approximation (SAA) for the lidar return with Monte Carlo calculations at small receiver field of views, where the SAA can be used for the evaluation of lidar signals from clouds and fogs. The diffraction component of light scattering by a local volume of a cloudy medium is fully taken into account and the geometrical part of light scattering field has been neglected. It has been found that the derived approximation provides useful approximation for the simulation of lidar signals from a cloudy medium close to its boundary, where the contribution of small-angle light scattering and propagation on the path from the cloud boundary to the observation point and back is significant. It has been found that the multiple light scattering enhancement factor A in the framework of the SSA for clouds with the same half - width parameter μ of the droplet size distribution depends just on two main parameters: optical depth τand the scale parameter s, which is equal to the ratio of the effective scattering angle to the receiver field of view.

SOST gene suppression stimulates osteocyte Wnt/β-catenin signaling to prevent bone resorption and attenuates particle-induced osteolysis

The most common cause for prosthetic revision surgery is wear particle-induced periprosthetic osteolysis, which leads to aseptic loosening of the prosthesis. Both SOST gene and its synthetic protein, sclerostin, are hallmarks of osteocytes. According to our previous findings, blocking SOST induces bone formation and protects against bone loss and deformation caused by titanium (Ti) particles by activating the Wnt/β-catenin cascade. Although SOST has been shown to influence osteoblasts, its ability to control wear-particle-induced osteolysis via targeting osteoclasts remains unclear. Mice were subjected to development of a cranial osteolysis model. Micro CT, HE staining, and TRAP staining were performed to evaluate bone loss in the mouse model. Bone marrow-derived monocyte-macrophages (BMMs) made from the C57BL/6 mice were exposed to the medium of MLO-Y4 (co-cultured with Ti particles) to transform them into osteoclasts. Bioinformatics methods were used to predict and validate the interaction among SOST, Wnt/β-catenin, RANKL/OPG, TNF-α, and IL-6. Local bone density and bone volume improved after SOST inhibition, both the number of lysis pores and the rate of skull erosion decreased. Histological research showed that β-catenin and OPG expression were markedly increased after SOST inhibition, whereas TRAP and RANKL levels were markedly decreased. In-vitro, Ti particle treatment elevated the expression of sclerostin, suppressed the expression of β-catenin, and increased the RANKL/OPG ratio in the MLO-Y4 cell line. TNF-α and IL-6 also elevated after treatment with Ti particles. The expression levels of NFATc1, CTSK, and TRAP in osteoclasts were significantly increased, and the number of positive cells for TRAP staining was increased. Additionally, the volume of bone resorption increased at the same time. In contrast, when SOST expression was inhibited in the MLO-Y4 cell line, these effects produced by Ti particles were reversed. All the results strongly show that SOST inhibition triggered the osteocyte Wnt/β-catenin signaling cascade and prevented wear particle-induced osteoclastogenesis, which might reduce periprosthetic osteolysis.Key messagesSOST is a molecular regulator in maintaining bone homeostasis.SOST plays in regulating bone homeostasis through the Wnt/β-catenin signaling pathway.SOST gene suppression stimulates osteocyte Wnt/β-catenin signaling to prevent bone resorption and attenuates particle-induced osteolysis.

Orientation of the spins of galaxies in the local volume

ABSTRACT We estimated the angular momentum, J, of 720 galaxies in the Local Volume with distances r < 12 Mpc. The distribution of the average angular momentum along the Hubble sequence has a maximum at the morphological type T = 4 (Sbc), while the dispersion of the J-values for galaxies is minimal. Among the Local Volume population, 27 elite spiral galaxies stand out, with an angular momentum > 0.15 of the Milky Way, J > 0.15JMW, making the main contribution ($\gt 90~{{\ \rm per\ cent}}$ ) to the total angular momentum of galaxies in the considered volume. Using observational data on the kinematics and structure of these galaxies, we determined the direction of their spins. We present the first map of the distribution of the spins of 27 nearby massive spiral galaxies in the sky and note that their pattern does not exhibit significant alignment with respect to the Local Sheet plane. The relationship between the magnitude of the angular momentum and stellar mass of the local galaxies is well represented by a power law with an exponent of (5/3) over an interval of six orders of magnitude of the mass of galaxies.

Luminescence Characteristics of the MOCVD GaN Structures with Chemically Etched Surfaces.

Gallium nitride is a wide-direct-bandgap semiconductor suitable for the creation of modern optoelectronic devices and radiation tolerant detectors. However, formation of dislocations is inevitable in MOCVD GaN materials. Dislocations serve as accumulators of point defects within space charge regions covering cores of dislocations. Space charge regions also may act as local volumes of enhanced non-radiative recombination, deteriorating the photoluminescence efficiency. Surface etching has appeared to be an efficient means to increase the photoluminescence yield from MOCVD GaN materials. This work aimed to improve the scintillation characteristics of MOCVD GaN by a wet etching method. An additional blue photo-luminescence (B-PL) band peaking at 2.7-2.9 eV and related to dislocations was discovered. This B-PL band intensity appeared to be dependent on wet etching exposure. The intensity of the B-PL was considerably enhanced when recorded at rather low temperatures. This finding resembles PL thermal quenching of B-PL centers. The mechanisms of scintillation intensity and spectrum variations were examined by coordinating the complementary photo-ionization and PL spectroscopy techniques. Analysis of dislocation etch pits was additionally performed by scanning techniques, such as confocal and atomic force microscopy. It was proved that this blue luminescence band, which peaked at 2.7-2.9 eV, is related to point defects those decorate dislocation cores. It was shown that the intensity of this blue PL band was increased due to enhancement of light extraction efficiency, dependent on the surface area of either single etch-pit or total etched crystal surface.

AI-based characterization of multiple sclerosis clinical symptomatology using lesion parenchymal fraction: empirical support for the topographical model of MS (P3-3.018)

<h3>Objective:</h3> To evaluate the relationship between lesion location, functional systems, and disability using an artificial intelligence (AI) model. <h3>Background:</h3> The topographical model of MS depicts localized lesion burden in a pool of variable neurological reserve, with the cervical cord at the shallow end. <h3>Design/Methods:</h3> 63 people with MS (30 RRMS, 33 SPMS, 51 female, baseline age 45.8±10.0 yrs) were longitudinally evaluated with MRI and clinical metrics (EDSS and functional system scores [FSS]) with median 2 time points, max. 8, (total: 154), follow-up 2.1±2.5 years. Imaging: icobrain was used to measure T2-FLAIR lesions on brain MRI, and adapted to measure T2 lesion volumes in cervical cord. To create a lesion/reserve ratio, localized lesion volume percentiles were divided by regional parenchymal volume percentile (cerebral, infratentorial, cervical cord), yielding regionally-specific lesion parenchymal fraction (LPF). Modeling: in 500 iterations, Random Forest (RF) regression models were trained to estimate cross-sectional EDSS and FSS. Estimations were Spearman correlated with actual scores; median correlation was assessed. To evaluate role of LPF, two estimator sets were used: 1) simple model: age and sex, 2) full model: age, sex, and topographical LPF. <h3>Results:</h3> Spearman correlations between fitted and true clinical scores were highest for overall EDSS (R=0.29), pyramidal (R=0.37), bowel/bladder (R=0.38), and cerebellar (R=0.27). Models including LPF outperformed the simple model in 100%, 100%, 98%, and 91% of iterations, respectively. The EDSS and pyramidal FSS were most strongly associated with infratentorial LPF, which also most strongly predicted conversion to SPMS. <h3>Conclusions:</h3> Lesion localization can be mapped to specific functional systems to explicate MS heterogeneity. Lesion parenchymal fraction, an assessment of lesion load/parenchymal volume ratio, is a quantified expression of the topographical model of MS and may be a useful MRI correlate of MS clinical symptoms. Using this metric, AI techniques can be refined to identify specific thresholds for conversion to SPMS. <b>Disclosure:</b> Dr. Krieger has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Biogen. Dr. Krieger has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for EMD Serono. Dr. Krieger has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Genentech. Dr. Krieger has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Novartis. Dr. Krieger has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for TG Therapeutics. Dr. Krieger has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Sanofi. Dr. Krieger has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for Expert Witness. The institution of Dr. Krieger has received research support from Novartis. The institution of Dr. Krieger has received research support from Bristol Myers Squibb. Thibo Billiet has received personal compensation for serving as an employee of icometrix. Miss Maes has received personal compensation for serving as an employee of icometrix. Dr. De Barros has received personal compensation for serving as an employee of Icometrix. Dr. Van Hecke has received personal compensation for serving as an employee of icometrix. Annemie Ribbens, 9599 has received personal compensation for serving as an employee of icometrix. Annemie Ribbens, 9599 has stock in icometrix. Chenyu Wang, 7886 has received personal compensation for serving as an employee of Sydney Neuroimaging Analysis Centre. The institution of Chenyu Wang, 7886 has received research support from Multiple Sclerosis Research Australia. Kain Kyle has received personal compensation for serving as an employee of Sydney Neuroimaging Analysis Centre. Kain Kyle has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Sydney Neuroimaging Analysis Centre. Linda Ly has nothing to disclose. Dr. Garber has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Garber has received research support from Trish MS Foundation. Michael Barnett has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Sydney Neuroimaging Analysis Centre. An immediate family member of Michael Barnett has received stock or an ownership interest from RxMx. The institution of Michael Barnett has received research support from Genzyme Sanofi. The institution of Michael Barnett has received research support from Biogen. The institution of Michael Barnett has received research support from Novartis.

Algorithm of Estimation of the Degree of Porosity Homogeneity of Foamed Concretes by Local Volumes by X-ray Computed Tomography Method.

X-ray CT is widely used to study the structure of foam concrete, the quality of which depends on the uniformity in porosity in local volumes (LV) of the samples. The purpose of this work is to substantiate the need to assess the degree of homogeneity of samples in terms of porosity according to LV. To achieve the goal, an appropriate algorithm has been developed and programmed in MathCad. To illustrate the capabilities of the algorithm, foam concrete modified with fly ash and thermally modified peat (TMP) was tested by CT. The information obtained by CT was processed by the proposed algorithm with variations in LV dimensions in order to estimate the distributions of mean values and standard deviations of porosity. Based on the data obtained, a conclusion was made about the high quality of foam concrete with TMP. The proposed algorithm can be used at the stage of improving the technologies for the production of high-quality foam concretes and other porous materials.

Signatures of exposure to childhood trauma in young adults in the structure and neurochemistry of the superior temporal gyrus.

Childhood trauma (CT) has been linked to increased risk for mental illness in adulthood. Although work in experimental animals has shown that early life stressors can affect inhibitory and excitatory neurotransmission in adult rodents, with possible excitotoxic effects on local grey matter volumes (GMV), the neurobiological mechanisms that mediate this relationship in humans remain poorly understood. To examine glutamate and gamma-aminobutyric acid (GABA) metabolite concentrations and potential excitotoxic effects on GMV, in adults who experienced CT. Fifty-six young adults (Mage = 20.41) were assigned to High CT (n = 29) and Low CT (n = 27) groups (by using the CT questionnaire) and underwent magnetic resonance spectroscopy (1H-MRS) to measure temporal lobe metabolite concentrations and volumetric imaging to measure GMV. Glutamate concentrations did not differ between groups; however, relative to the Low CT group, participants in the High CT group had reduced GABA concentrations in the left superior temporal gyrus (STG) voxel. Furthermore, logistic regression showed that participants with low left STG GABA concentrations and low left STG volumes were significantly more likely to be in the high CT group. This study provides the first evidence that both low GABA concentrations and its interaction with GMV in the left STG are associated with high levels of CT and suggest that altered inhibitory neurotransmission/metabolism may be linked to a lower GMV in the left STG in adults who experienced CT. Future studies are warranted to establish if utilizing these measures can stratify clinical high-risk and predict future clinical outcomes in high CT individuals.