Volumetric Changes Research Articles

Redispersible Acrylic Ester Polymers: Effect of Polymer Property Changes Due to Polymerization Method Modification and Functional Additives on the Performance of Polymer Cement Mortar

This paper presents an experimental study aimed at improving the performance of polymer cement mortar by evaluating the properties of acrylic ester redispersible polymers, synthesized using a change in polymerization method from emulsion monomer to monomer dropwise addition methods, along with the use of a functional additive in the form of a foaming agent. To achieve the research objectives, a polymer with a glass transition temperature of −11 °C was synthesized by fixing the monomer ratio, particle-size distribution, and glass transition temperature, and the physical properties of the polymer cement mortar were assessed. The results showed that polymers synthesized using the modified polymerization method increased elongation at break and possessed a 35% smaller average particle size. The use of the foaming agent also resulted in enhanced tensile strength. The polymer cement mortars made with these respective polymers demonstrated improvements in compressive strength 11~25%, flexural strength 53~77%, bond strength 78~113%, volumetric changes 65~88%, and water absorption 30~70%. These findings suggest that changes in the polymerization method and the incorporation of functional additives influence the average particle size and air entrainment control properties of the polymers, thereby positively impacting the performance of the cement hydrates.

Impact of Wetting and Drying Cycles on the Hydromechanical Properties of Soil and Implications on Slope Stability

The soil-based infrastructure is the backbone of the global economy, connecting people, enhancing quality of life, and promoting health and safety. However, its vulnerabilities are becoming apparent due to climate change, mainly through frequent wetting and drying (wd) cycles. Despite few studies in the past, research showing the stability of flood embankments in the long term, incorporating the impact of wetting and drying cycles on the hydromechanical characteristics of soil, is scarce. This study aimed to assess the impact of controlled wd cycles on the hydromechanical properties of clay and silty sand soils and its implications for the stability of a typical flood embankment. Volumetric changes were monitored during the wd cycles. The soil water characteristic curve (SWCC), saturated hydraulic conductivity (ksat), effective cohesion (c′), and effective angle of internal friction (ϕ′) were measured at 1 and 10 wd cycles. The results indicated that the 10 wd cycles decreased the saturated moisture content and resulted in a flatter SWCC compared to the 1 wd cycle for clayey soil. The ksat value was also significantly higher at 10 wd cycles than 1 wd cycle for clayey soil. An insignificant difference was found in both the SWCC and ksat at 1 and 10 wd cycles for silty sand soil. The ϕ′ value for the clayey soil decreased from 28.5 to 20.1 as the wd cycles increased from 1 to 10, while c′ remained unchanged at 10 kN/m2. On the other hand, for the silty sand soil, ϕ′ increased from 34.6 to 37.5 with an increase in wd cycles from 1 to 10, and c′ remained constant at 1 kN/m2. Numerical modelling of transient water flow coupled with a slope stability analysis revealed that the stability of a flood embankment depends on the evolution of soil hydromechanical properties due to wd cycles and the duration of flooding. These findings underscore the need for proactive measures to mitigate landslide risks in regions prone to frequent wd cycles, thereby ensuring the safety and resilience of slopes and associated infrastructure.

Melt Expansion and Thermal Transitions of Semiconducting Polymers in Thin Films

AbstractThe molecular self‐organization and reorganization and thus volumetric and density changes during structural relaxation and melting of modern organic semi‐conducting materials remains largely unknown, particularly in the device relevant thin film geometry where the initial state may be structurally quenched away from equilibrium. Here, the apparent mass‐thickness of a range of semi‐conducting polymeric or molecular model materials systems is measured through in situ ellipsometry. Surprisingly, the volume changes upon melting correlate inversely, with a few exceptions, to the quality of crystallinity found via x‐ray methods (i.e., directly correlate with the paracrystalline g‐parameter) rather than the melting enthalpy that is possibly a proxy for the degree of crystallinity. This study also observes changes in orientation and/or density due to segmental relaxation during the first heat, thus complementing other characterization methods that measure relaxation or reorganization transitions. Semiconducting materials exhibit very large melt expansion and a richer phase‐behavior compared to commodity polymers, presumably due to their complex chemical structure. The results delineate an important and novel structure‐function relation that, together with simulations constrained by these results, will lead to better rational design of semi‐conducting materials.

Volumetric changes of porcine collagen matrix and free gingival grafts for soft-tissue grafting to increase the width of keratinized tissue around dental implants: a retrospective clinical study.

To compare three-dimensional changes of aporcine derived collagen matrix (CM) and free gingival grafts (FGG) for increasing keratinized tissue (KT) at dental implants over a 24-month follow-up period. This retrospective study enrolled 25 patients exhibiting 41 implants with deficient KT width (i.e., < 2mm) who underwent soft tissue augmentation using either CM (11 patients/15 implants) or FGG (14 patients/26 implants). The primary outcome was tissue thickness change (mm) at treated implant sites between 1- (S0), 12- (S1), and 24-months (S2). Secondary outcome was the changes of KT width over a 24-month follow-up period. Dimensional analyses from S0 to S1 and from S0 to S2 revealed a mean decrease in tissue thickness of -0.05 ± 0.35mm and - 0.31 ± 0.41mm in the CM group, and - 0.23 ± 0.38mm and - 0.22 ± 0.81mm in the FGG group, with no significant differences found between the groups (S0-S1: p = 0.14, S0-S2: p = 0.58). Within S1 and S2, the CM and FGG groups displayed comparable tissue thickness reduction (CM: -0.32 ± 0.53mm, FGG: -0.02 ± 0.21mm; p = 0.07). The FGG group exhibited a significantly greater KT gain 24-months compared to the CM group (CM: 1.50 ± 1.14mm, FGG: 4.04 ± 1.65mm; p < 0.001). CM and FGG were associated with comparable three-dimensional thickness changes over a period of 24 months. A significantly wider KT band could be established in the FGG group.

Brief communication: Monitoring impending slope failure with very high-resolution spaceborne synthetic aperture radar

Abstract. We demonstrate how high spatial and temporal resolution spaceborne synthetic aperture radar (SAR) imagery can improve slope deformation monitoring. We process ICEYE data over the Brienz/Brinzauls slope instability in the Swiss Alps, where a catastrophic failure occurred on 15 June 2023. Image correlation applied to retrieve surface velocities shows results comparable to in situ measurements. Pre- and post-failure acquisitions used to map areas invaded by debris and to compute associated volumetric changes are in good agreement with photogrammetric data. This study sets the baseline for new-generation satellite SAR data aimed at providing timely information in landslide early warning scenarios.

An extended kinematic hardening constitutive model to include unsaturated behaviour for the prediction of soil deterioration

Linear geotechnical infrastructure undergoes seasonal volumetric changes due to climatic and hydrological cycles, leading to progressive failure of the soil mass and performance deterioration. The magnitude of the seasonal cycles of pore water pressure is expected to be increased by more extreme and frequent wet and dry events, leading to an accelerated deterioration process. Advanced constitutive models for unsaturated soils able to reproduce the observed behaviour are therefore required. A new advanced constitutive model for the hydro-mechanical behaviour of unsaturated soils is formulated and implemented within the framework of elasto-plasticity with internal variables. The effect of recent suction history is incorporated using a kinematic hardening constitutive model augmented by elements of bounding surface plasticity, initially developed for saturated soils, which is further extended to the unsaturated range through the inclusion of a loading collapse curve. The model permits the retention of information on recent stress history, allows prediction of irrecoverable stiffness and strength loss, and replicates the hysteretic response during cyclic loading. The model has been implemented in a constitutive driver using an implicit numerical scheme and its predictive capabilities are demonstrated by performing numerical simulations of a series of laboratory experiments involving complex sequences of isotropic loading, wetting, drying and shearing stages.

Innovations in Energy Through Nanomaterials Enhancing Solid-State Battery Safety and Efficacy

This paper explores the potential of Si-based nanomaterials to enhance the performance of lithium-ion batteries (LIBs), particularly for electric vehicles (EVs). Traditional graphite anodes limit the energy density and range of EVs, increasing the need to search for alternative materials like silicon, which offers a much higher theoretical specific capacity. However, silicon’s application has been challenged by significant volume changes during cycling, leading to mechanical stress and failure. The use of nanotechnology, especially silicon nanomaterials, offers promising solutions to these challenges. Silicon nanostructures, such as nanowires, exhibit enhanced mechanical properties, allowing them to withstand volumetric changes and maintain high capacity during cycling. This review delves into the chemo-physical properties of silicon, the challenges posed by silicon anodes (SAs), and the recent advancements in silicon nanomaterials. Additionally, it also discusses different approaches to enhancing the performance of Si-based anodes, as well as the difficulties that exist now and the directions that future research in this exciting area is headed.

Investigation on Miage/Brenva Glaciers in The Alps From 50s to-date Based on Remote-Sensing Data

Abstract. The Miage and Brenva Glaciers in Mount Blanc Massif (Italy) are two of the major glaciers in the Alps. To assess the evolution of these glaciers, we use multiple data sources from remote sensing, and we adopt different techniques to extract important information on their conditions during a long period (i.e., ~60 years). The first approach, which is based on the use of aerial photos and satellite imagery (SPOT 6), allows assessing the volume change of Miage Glacier over the period 1952–2014. The second approach, which is based on the use of optical satellite observations such as Landsat 5/8/9 and Sentinel 2, aims to evaluate the spatial variability and the temporal trends of the snow cover of both glaciers from 1984 up to now. The achieved results, that are coherent with the ones reported by the scientific literature, show that volumetric changes of Miage Glacier underwent a period of gain between 1975–1991, followed by an impressive decay phase. Concerning the snow cover analysis, our findings highlight that for both glaciers the area covered by snow reduces persistently year-by-year, especially in the case of the Miage Glacier.

Relationship between regional volume changes and water diffusion in fixed marmoset brains: an in vivo and ex vivo comparison

Ex vivo studies of the brain are often employed as experimental systems in neuroscience. In general, brains for ex vivo MRI studies are usually fixed with paraformaldehyde to preserve molecular structure and prevent tissue destruction during long-term storage. As a result, fixing brain tissue causes microstructural changes and a decrease in brain volume. Therefore, the purpose of this study was to investigate the regional effect of brain volume and microstructural changes on the restricted diffusion of water molecules in the common marmoset brain using in vivo and ex vivo brains from the same individual. We used 9.4T magnetic resonance imaging and also compared the T2-weighted images and diffusion-weighted imaging (DWI) data between in vivo and ex vivo brains to investigate changes in brain volume and diffusion of water molecules in 12 common marmosets. We compared fractional anisotropy, mean diffusivity, AD (axial diffusivity), and radial diffusivity values in white matter and gray matter between in vivo and ex vivo brains. We observed that AD showed the strongest correlation with regional volume changes in gray matter. The results showed a strong correlation between AD and changes in brain volume. By comparing the in vivo and ex vivo brains of the same individual, we identified significant correlations between the local effects of perfusion fixation on microstructural and volumetric changes of the brain and alterations in the restricted diffusion of water molecules within the brain. These findings provide valuable insights into the complex relationships between tissue fixation, brain structure, and water diffusion properties in the marmoset brain.

Core‐Shell Amorphous FePO4 as Cathode Material for Lithium‐Ion and Sodium‐Ion Batteries

AbstractAmorphous FePO4 (AFP) is a promising cathode material for lithium‐ion and sodium‐ion batteries (LIBs &amp; SIBs) due to its stability, high theoretical capacity, and cost‐effective processing. However, challenges such as low electronic conductivity and volumetric changes seriously hinder its practical application. To overcome these hurdles, core‐shell structure synthesis emerges as a useful solution. In this work, we for the first time made this comprehensive review on the progresses of core‐shell amorphous FePO4 (CS‐AFP). This review summarizes 1) various synthesis methods such as template method, microemulsion method, and other methods, 2) characterization techniques, and 3) their involvement in improving electrochemical performance in LIBs and SIBs. In terms of further understanding the underlying mechanisms of advancing electrochemical performance of CS‐AFP, the future perspective on two main aspects were insighted: (i) in situ characterization and (ii) novel designs of materials and structure for CS‐AFP.

Assessing 3D volumetric asymmetry in facial palsy patients via advanced multi-view landmarks and radial curves

The research on facial palsy, a unilateral palsy of the facial nerve, is a complex field with many different causes and symptoms. Even modern approaches to evaluate the facial palsy state rely mainly on stills and 2D videos of the face and rarely on dynamic 3D information. Many of these analysis and visualization methods require manual intervention, which is time-consuming and error-prone. Moreover, they often depend on alignment algorithms or Euclidean measurements and consider only static facial expressions. Volumetric changes by muscle movement are essential for facial palsy analysis but require manual extraction. We propose to extract an estimated unilateral volumetric description for dynamic expressions from 3D scans. Accurate landmark positioning is required for processing the unstructured facial scans. In our case, it is attained via a multi-view method compatible with any existing 2D predictors. We analyze prediction stability and robustness against head rotation during video sequences. Further, we investigate volume changes in static and dynamic facial expressions for 34 patients with unilateral facial palsy and visualize volumetric disparities on the face surface. In a case study, we observe a decrease in the volumetric difference between the face sides during happy expressions at the beginning (13.8 ± 10.0 mm3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {mm}^{3}$$\\end{document}) and end (12.8 ± 10.3 mm3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {mm}^{3}$$\\end{document}) of a ten-day biofeedback therapy. The neutral face kept a consistent volume range of 11.8-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-$$\\end{document}12.1 mm3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {mm}^3$$\\end{document}. The reduced volumetric difference after therapy indicates less facial asymmetry during movement, which can be used to monitor and guide treatment decisions. Our approach minimizes human intervention, simplifying the clinical routine and interaction with 3D scans to provide a more comprehensive analysis of facial palsy.

Designing Tin and Hard Carbon Architecture for Stable Sodium‐Ion Battery Anode

The lack of anodes stability is one among key barriers to the widespread commercialization of sodium‐ion batteries (SIBs). This is attributed to graphite, a well‐known common anode material for a range of commercial batteries including lithium‐ion batteries (LIBs), which limits the insertion of sodium (Na) ions due to their large ionic size. Tin (Sn) has shown its potential as a suitable anode material because it exhibits high capacities in conversion and alloying reactions. However, it endures significant volumetric expansion and slower reaction rates during sodiation. To overcome these challenges, this work presents a novel anode material for SIBs where a 2D layered architecture of Sn with a hard carbon (HC) buffer layer is engineered using physical vapor deposition technique. This novel anode (SnHT/HC) exhibits a high initial capacity of 470 mAhg−1 and an exceptional retention of 438 mAhg−1 after 3000 cycles at 0.2C, with 99 % Coulombic efficiency. SnHT/HC testing at varying fast charge and discharge C‐rate of 5C, 10C, 15C, and 50C has shown promising results. Better electron transport and reduced volumetric changes are perceived to enhance the overall performance of SnHT/HC electrodes.

Neuroimaging correlates of cognitive disorders secondary to electroconvulsive therapy: A systematic review

ObjectivesElectroconvulsive therapy is known as an efficient therapy, which is sometimes recommended for the management of severe and resistant depression. However, ECT is associated with cognitive adverse effects. The study of the neurobiological correlates of the cognitive adverse effects of ECT has been covered in few published reviews. However, these mechanisms have been investigated in an increasing number of studies in recent years, particularly in neuroimaging. This systematic review of the literature focuses on correlates between changes in structural or functional neuroimaging and impairment of cognitive functions during the ECT treatment. MethodsWe conducted a systematic review of the literature using PRISMA methodology. Searches were performed on the Medline and Web of Science databases using the following equation: “electroconvulsive therapy AND (MRI OR fMRI OR DTI OR neuroimaging) AND depression AND cogniti*”. ResultsThis article highlights the significant heterogeneity of the results. In structural imaging, approximately 50% of the studies did not report any correlation between volumetric changes and neuropsychological changes. In studies that did highlight a correlation, the latter was mainly reported with changes in the hippocampus. From a functional perspective, we highlighted a correlation between changes in the connectivity of the hippocampal region and cognition. ConclusionThese results demonstrate a growing interest in understanding the neurobiological mechanisms underlying cognitive disorders secondary to ECT treatment. The ultimate aim behind this understanding is to adopt a more effective prevention strategy vis-à-vis these adverse effects.

Boosting the Sodiation Kinetics of Sn Anode Using a Yolk-Shell Nanohybrid Structure for High-Rate and Ultrastable Sodium-Ion Batteries.

Metallic Sn (Tin) is a promising anode material for Na-ion batteries owing to its high theoretical capacity of 870mAhg-1. However, its large volumetric changes, interfacial instability, and sluggish sodiation kinetics limit its practical applications. Herein, a hierarchical yolk-shell nanohybrid composed of an Sn yolk and a Carbon/Silicon oxycarbide (C/SiOC) bilayer shell is prepared via the simple pyrolysis of a silicone oil dispersion containing an Sn precursor. The multifunctional bilayer helps boost sodiation kinetics by providing conductive pathways, enhancing the reversible capacity through surface capacitive reactions, and stabilizing the electrode/electrolyte interface. Abundant void interspaces inside the yolk-shell structure accommodate large volume changes of the Sn yolk. The Sn@C/SiOC nanohybrid demonstrates high specific capacity (≈500mAhg-1 at 1Ag-1), remarkable rate performance up to 10Ag-1, and ultrastable cyclability (91.1% retention after 1500 cycles at 5Ag-1). This yolk-shell nanohybrid structuring can guide the development of various high-capacity anodes for energy storage applications.

Residual post-infarct myocardial inflammation detected by 68Ga-DOTATATE PET/MRI predicts long-term adverse cardiac remodelling

Abstract Background Maladaptive inflammatory responses are associated with adverse cardiac remodelling after myocardial infarction (MI), but clinical methods for detecting residual myocardial inflammation post-MI are lacking. Purpose To investigate somatostatin receptor subtype 2 (SST2) positron emission tomography (PET)/magnetic resonance imaging (MRI) using 68Ga-DOTATATE after MI. Methods In a prospective observational cohort study, infarct-related myocardial inflammation detected by 68Ga-DOTATATE PET at 2wk and 3mo post-MI was compared with MRI characteristics including left ventricular (LV) volumetric changes at 1yr, as well circulating immune cell phenotyping and serum proteomic markers. Patients with a prior history of MI or heart failure were excluded. Histological SST2 expression was assessed in myocardial biopsies. Results 38 participants (mean age 60 [SD 9] years; 84% male) with recent MI were enrolled, of whom 58% had an ST-segment elevation MI. Mean peak Troponin I was 16,665 (range 408 to &amp;gt;25,000) ng/L and mean post-infarct LV ejection fraction was 51 (SD 9) %. 68Ga-DOTATATE maximum standardized uptake values (SUVmax) at 10 (SD 4) days accurately localised infarcted myocardial segments defined by late-gadolinium enhancement MRI (LGE; Fig. 1); were 14.2% higher in akinetic/hypokinetic vs. normo-kinetic segments (p&amp;lt;0.0001); and were correlated both with peak segmental strain (r=0.47, p=0.003) and segmental T1 values (r=0.51, p=0.02). Mean infarct SUVmax was 19.7% lower on repeat PET/MRI after a mean 102 (SD 22) days (p&amp;lt;0.0001), and this change was in keeping with parallel reductions in T2-weighted oedema signal on MRI and serum biomarkers of cardiac injury and systemic inflammation. Residual inflammation assessed by mean infarct SUVmax at 3mo was correlated with ΔLV indexed end-diastolic volume at 369 (SD 14) days, after adjustment for baseline infarct size and other clinical variables (p=0.038). The 3mo:2wk ratio of mean infarct SUVmax was an even stronger predictor of adverse myocardial remodelling (p=0.0025). Circulating SST2+ classical monocytes were correlated with infarct 68Ga-DOTATATE signal (r=0.47, p=0.02), and SST2 was co-expressed with CD68+ macrophages in inflamed myocardial specimens of patients with recent MI and ischaemic heart failure. After statistical feature selection and multiple comparisons adjustments, among the blood markers associated with 3mo:2wk infarct SUVmax was CCL25, a chemokine involved in macrophage recruitment which has been implicated in adverse cardiac remodelling. Conclusions Here, in the first prospective clinical study of serial SST2 PET/MRI after MI, we show that 68Ga-DOTATATE can identify and track resolving infarct-related myocardial inflammation. Moreover, residual inflammation detected by 68Ga-DOTATATE is associated with long-term adverse myocardial remodelling and could provide a potential future imaging biomarker to help stratify high-risk patients for emerging immunomodulatory therapies.Figure 1.68Ga-DOTATATE PET-MRI after MI

Progressive postoperative atrophy of ipsilateral thalamus, putamen, and globus pallidus in patients with temporal lobe epilepsy: A volumetric analysis.

Cortical atrophy close to medial temporal structures has been described consistently in patients with temporal lobe epilepsy (TLE). Successful TLE surgery may have a neuroprotective effect preventing further atrophy of temporal and extratemporal cortex. However, the effects of epilepsy surgery on subcortical structures demand additional enlightenment. This work aimed to determine how epilepsy surgery affects volumes of subcortical structures in medically refractory temporal lobe epilepsy patients. We compared MRI volumes of subcortical structures in 62 patients with TLE (36 left, 26 right) before and after anterior temporal lobectomy with 38 TLE patients (20 left, 18 right) who were considered to be good surgical candidates and had at least two brain MRIs. There were no volume differences in subcortical structures on preoperative and initial MRIs of non-operated TLE patients. At baseline, the ipsilateral thalamus and putamen in TLE patients were marginally smaller than contralateral structures. Operated patients showed a significant postoperative volume reduction in ipsilateral thalamus, putamen, and globus pallidus. In contrast, there were no significant volumetric reductions in non-operated patients longitudinally. There were no volumetric changes associated with different surgical outcomes or different postoperative cognitive outcomes. Our study demonstrated postoperative volume loss of thalamus, putamen and globus pallidus ipsilaterally to the side of resection. Our findings suggest surgery-related changes, likely Wallerian degeneration within subcortical networks not related to seizure or cognitive outcome. We studied 100 patients with epilepsy, comparing those who had surgery to those who did not. After surgery, the thalamus, putamen and globus pallidus on the same side as the surgery shrank significantly, but not in non-surgery patients. This suggests surgery-related changes in deeper brain structures, unrelated to seizure freedom or cognitive outcomes. This research sheds additional light on the response of the subcortical structure to epilepsy surgery, highlighting potential areas for further study.

UAV REMOTE SENSING APPLICATIONS IN BEACH-CLIFF SYSTEM MONITORING OF MORPHODYNAMIC PROCESSES

This study aims to evaluate the morphodynamic changes in a beach-cliff system in northeastern Brazil using high resolution data collected by UAV-SfM techniques to understand the geomorphic changes of the coastal landscape. The study used the Geomorphic Change Detection (GCD) method applied to short-term monitoring. This method uses Digital Elevation Models (DEMs) to determine the morphological changes in terms of both erosion and deposition through DEMs of Difference (DoDs). The difference gridded models are acquired by drone-based remote sensing, which can accurately and efficiently provide ultra-high resolution imagery and digital surface model data to measure volumetric changes. The geomorphic changes are observed on high resolution maps. The multi-temporal analysis revealed significant volumes of erosion and deposition throughout the beach-cliff system over the study period. In the first interval (May/2021 - November/2021), the cliff recorded -8,715 m³ of erosion and 2,816 m³ of deposition, with the beach sector showing erosion in 86% of its area. In the second period (November/2021 - March/2022), more severe erosion rates were observed on the cliff, reaching -10,853 m³ with 51% of its area eroded, while the beach showed the opposite behavior to that previously analyzed, with 73% of the beach experiencing an accumulation of sand and a positive balance of 5,960 m³. The results of this study can be fruitful in identifying the different of geomorphology hazards, coastal impacts of cliff urbanization and in the use of remotely piloted aircraft in coastal monitoring. Furthermore, the results indicate that the management of the beach-cliff system must be integrated and never dissociated, as is generally done by coastal managers. Keywords: Geomorphometry; DEMs; Drone-Based Remote Sensing; Mass Movement; Elevation and Volumetric.

Dendritic spines of layer 5 pyramidal neurons of the aging somatosensory cortex exhibit reduced volumetric remodeling.

Impairments in synaptic dynamics and stability are observed both in neurodegenerative disorders and in the healthy aging cortex, which exhibits elevated dendritic spine turnover and decreased long-term stability of excitatory connections at baseline, as well as an altered response to plasticity induction. In addition to the discrete gain and loss of synapses, spines also change in size and strength both during learning and in the absence of neural activity, and synaptic volume has been associated with stability and incorporation into memory traces. Furthermore, intrinsic dynamics, an apparently stochastic component of spine volume changes, may serve as a homeostatic mechanism to prevent stabilization of superfluous connections. However, the effects of age on modulation of synaptic weights remain unknown. Using two-photon excitation (2PE) microscopy of spines during chemical plasticity induction in vitro and analyzing longitudinal in vivo 2PE images after a plasticity-inducing manipulation, we characterize the effects of age on volumetric changes of spines of the apical tuft of layer 5 pyramidal neurons of mouse primary somatosensory cortex. Aged mice exhibit decreased volumetric volatility and delayed rearrangement of synaptic weights of persistent connections, as well as greater susceptibility to spine shrinkage in response to chemical long-term depression. These results suggest a deficit in the aging brain's ability to fine-tune synaptic weights to properly incorporate and retain novel memories. This research provides the first evidence of alterations in spine volumetric dynamics in healthy aging and may support a model of impaired processing and learning in the aged somatosensory system.Significance Statement Aging is known to impact cognitive functions and sensory processing, yet the underlying mechanisms at the synaptic level remain unclear. This study investigates dendritic spine dynamics of layer 5 pyramidal neurons in the aging somatosensory cortex. By employing two-photon excitation microscopy and analyzing spine volume changes during plasticity induction, we reveal that aged mice exhibit decreased volumetric volatility and delayed synaptic weight rearrangement. These alterations may impair the brain's ability to fine-tune synaptic weights, which is crucial for incorporating and retaining new memories. This research provides the first evidence of altered spine volumetric dynamics in healthy aging, suggesting a potential mechanism for impaired processing and learning in the aged cortex. Understanding these changes could aid in mitigation of age-related cognitive decline.

Histology-guided MRI segmentation of brainstem nuclei critical to consciousness.

While substantial progress has been made in mapping the connectivity of cortical networks responsible for conscious awareness, neuroimaging analysis of subcortical arousal networks that modulate arousal (i.e., wakefulness) has been limited by a lack of a robust segmentation procedures for brainstem arousal nuclei. Automated segmentation of brainstem arousal nuclei is an essential step toward elucidating the physiology of arousal in human consciousness and the pathophysiology of disorders of consciousness. We created a probabilistic atlas of brainstem arousal nuclei built on diffusion MRI scans of five ex vivo human brain specimens scanned at 750 μm isotropic resolution. Labels of arousal nuclei used to generate the probabilistic atlas were manually annotated with reference to nucleus-specific immunostaining in two of the five brain specimens. We then developed a Bayesian segmentation algorithm that utilizes the probabilistic atlas as a generative model and automatically identifies brainstem arousal nuclei in a resolution- and contrast-agnostic manner. The segmentation method displayed high accuracy in both healthy and lesioned in vivo T1 MRI scans and high test-retest reliability across both T1 and T2 MRI contrasts. Finally, we show that the segmentation algorithm can detect volumetric changes and differences in magnetic susceptibility within brainstem arousal nuclei in Alzheimer's disease and traumatic coma, respectively. We release the probabilistic atlas and Bayesian segmentation tool in FreeSurfer to advance the study of human consciousness and its disorders.

Behavior of Slab-on-Grade Resting on Expansive Soil

Abstract This paper discusses a case study of a residential building in Benghazi that features slab-on-grade foundations supported by expansive soils. Although such structures are uncommon in the area, they can suffer serious damage due to volumetric changes in the soil caused by wetting and drying. The building has a total plan area of 200 m², with tie beams located 1.2 m above the formation level, and expansive soil used as backfill. After being moistened and lightly compacted, 100 mm thick concrete slabs were poured between the tie beams, resulting in varying slab sizes. Following a month of heavy rainfall, significant cracking—longitudinal, diagonal, and warping—occurred in the slabs due to uneven deformation from the expansive soil. The paper includes photographs of these deformations and cracks, along with an analysis of the geotechnical properties of the expansive soil, including its swelling and shrinking characteristics. It also employs an approach to predict the pressure exerted on the slabs due to differential heave.