Dynamic Volume Changes Research Articles

Dynamic Coupling of Internal Strain Field and Lithium Pathway within Individual Battery Particles in Solid State Batteries

In all-solid-state batteries (ASSBs), (electro)chemo-mechanical aspects such as uneven interfaces, cathode-electrolyte interphase formation, delamination, fracture, defects, etc., are the major factors in capacity fade but remain largely unknown.Nonhomogeneous transfer of lithium ions can cause significant variations in strain and stress within battery electrodes, leading to degradation in battery performance. In all-solid-state batteries (ASSBs), the lithium pathway and the associated strain/stress field become more intricate due to the (electro)chemo-mechanical reaction at the electrode-electrolyte interfaces. The dynamic volume change in active particles are heavily influencing by strength of the solid electrolyte and interfacial conformality. This can continually alter the lithium pathway and the internal stress field, leading to recurrent redefinitions of (electro)chemo-mechanical environment.Here, we have developed an operando coherent X-ray imaging platform and associated analysis methodologies. This technology can track the nanoscale transport of lithium and the strain evolution of individual electrode particles in ASSBs. With this platform, we gained a comprehensive electrochemical and mechanical understanding of the cycling properties of single electrode particles in ASSBs.

Dynamic Volume Change of Li2S-Based Active Material and the Influence of Stacking Pressure on Capacity in All-Solid-State Batteries

Dynamic Volume Change of Li₂S-Based Active Material and the Influence of Stacking Pressure on Capacity in All-Solid-State Batteries

Exploring the topographical pattern beneath the water surface: Global bathymetric volume-area-height curves (BVAH) of inland surface water bodies

Global inland surface water bodies such as lakes and reservoirs, important components of the hydrosphere and ecosphere, are increasingly affected by climate change. Generating bathymetric volume-area-height (BVAH) curves for global inland surface water bodies can enhance our understanding of their topography and climate impacts. However, accurately quantifying the topographic patterns of these water bodies remains challenging due to the difficulties in collecting comprehensive bathymetric data. Therefore, we collected and processed over 2000 bathymetric maps of global water bodies from over 50 different data sources and then developed the BVAH model. Finally, the BVAH hydrological curves of 16671 global inland surface water bodies (larger than 10 km2) were generated. The results include but are not limited to (1) For most targeted water bodies, area (A) and volume (V) exhibit significant power function relationships with surface heights (H), with optimal power values quantified as 1.42 for A and 2.42 for V. (2) The BVAH model outperforms GLOBathy in estimating area and volume changes, achieving higher correlation coefficients (CC) of approximately 0.962 for the area and 0.991 for volume, and demonstrating lower percentages of root mean squared errors (PRMSE) around 10.9% for the area and 4.8% for volume. (3) In the case study of the Xizang Plateau and various large global reservoirs, the BVAH curve database can capture dynamic volume changes. As a unified simulation of the bathymetric topographical patterns, our bathymetric dataset and corresponding BVAH curve database have great potential to contribute to effective water resource management and ecological conservation efforts worldwide.

Cystic vestibular schwannoma – a subgroup analysis from a comparative study between radiosurgery and microsurgery

Some vestibular schwannoma (VS) show cystic morphology. It is known that these cystic VS bear different risk profiles compared to solid VS in surgical treatment. Still, there has not been a direct comparative study comparing both SRS and SURGERY effectiveness in cystic VS. This retrospective bi-center cohort study aims to analyze the management of cystic VS compared to solid VS in a dual center study with both microsurgery (SURGERY) and stereotactic radiosurgery (SRS). Cystic morphology was defined as presence of any T2-hyperintense and Gadolinium-contrast-negative cyst of any size in the pre-interventional MRI. A matched subgroup analysis was carried out by determining a subgroup of matched SURGERY-treated solid VS and SRS-treated solid VS. Functional status, and post-interventional tumor volume size was then compared. From 2005 to 2011, N = 901 patients with primary and solitary VS were treated in both study sites. Of these, 6% showed cystic morphology. The incidence of cystic VS increased with tumor size: 1.75% in Koos I, 4.07% in Koos II, 4.84% in Koos III, and the highest incidence with 15.43% in Koos IV. Shunt-Dependency was significantly more often in cystic VS compared to solid VS (p = 0.024) and patients with cystic VS presented with significantly worse Charlson Comorbidity Index (CCI) compared to solid VS (p < 0.001). The rate of GTR was 87% in cystic VS and therefore significantly lower, compared to 96% in solid VS (p = 0.037). The incidence of dynamic volume change (decrease and increase) after SRS was significantly more common in cystic VS compared to the matched solid VS (p = 0.042). The incidence of tumor progression with SRS in cystic VS was 25%. When comparing EOR in the SURGERY-treated cystic to solid VS, the rate for tumor recurrence was significantly lower in GTR with 4% compared to STR with 50% (p = 0.042). Tumor control in cystic VS is superior in SURGERY, when treated with a high extent of resection grade, compared to SRS. Therapeutic response of SRS was worse in cystic compared to solid VS. However, when cystic VS was treated surgically, the rate of GTR is lower compared to the overall, and solid VS cohort. The significantly higher number of patients with relevant post-operative facial palsy in cystic VS is accredited to the increased tumor size not its sole cystic morphology. Cystic VS should be surgically treated in specialized centers.

Synergistic effect of microscopic buckle and macroscopic coil for self-powered organ motion sensor

Although soft mechano-electrochemical energy harvesters have attracted considerable attention as wearable sensors, they face challenges, including low output performance, high Young’s modulus and low energy-conversion efficiency. To address these limitations, we introduce a novel design featuring macroscopically coiled and microscopically buckled fibres to improve the mechano-electrochemical energy-harvesting capability, thereby maximising capacitance change and affording higher electrical output. The harvester achieved a gravimetric peak current density of 121 A/kg and a peak power density of 16 W/kg. Moreover, the harvester showed enhanced stretchability under a strain of over 400 %, low Young’s modulus of 0.2 MPa and an energy conversion efficiency of 0.33 %. Furthermore, when implanted in a pig’s bladder, it showed minimal impact during expansion and contraction thanks to its softness and provided real-time electrical output in response to static and dynamic volume changes.

Dynamic liver volume change in predicting hepatic decompensation and long-term effects of stereotactic body radiation therapy.

This study aimed to investigate the association between liver volume change and hepatic decompensation and compare the risk of hepatic decompensation in patients with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) who underwent stereotactic body radiation therapy (SBRT). A retrospective review of SBRT-treated HCC and compensated LC without HCC patients was conducted. Liver volume was measured using auto-segmentation software on liver dynamic computed tomography scans. The decompensation event was defined as the first occurrence of refractory ascites, esophageal variceal bleeding, hepatic encephalopathy, or spontaneous bacterial peritonitis. We evaluated the association between the rate of liver volume decrease and hepatic decompensation and compared decompensation events between the SBRT and LC cohorts using propensity score matching. A total of 138 patients from the SBRT cohort and 488 from the LC cohort were analyzed. The rate of liver volume decrease was associated with the risk of decompensation events in both cohorts. The 3-year rate of decompensation events was significantly higher in the group with a liver volume decreasing rate>7%/year compared with the group with a rate<7%/year. In the propensity score-matched cohort, the 3-year rate of decompensation events after a single session of SBRT was not significantly different from that in the LC cohort. The rate of liver volume decrease was significantly associated with the risk of hepatic decompensation in both HCC patients who received SBRT and LC patients. A single session of SBRT for HCC did not result in a higher decompensation rate compared with LC.

Polymer configuration conversion mechanism in dynamically stable interface of silicon anodes

During the lithiation process, –CN– groups in the PHATN coordinate with Li+ to form –C–N–Li– bonds on PHATN molecule layer. The dynamic volume change of the PHATN molecule provides excellent protection against structural collapse.

Framework reinforced orderly-woven superhydrophobic metal–carbon composites for efficient emulsion separation in harsh environments

The primary barrier to the widespread use of super-wetting materials is the surface's limited resistance to physical damage, which leads to poor mechanical qualities. In this study, framework-reinforced orderly-woven superhydrophobic metal spiral coil-carbon fibers composites (SMSC-CFsC) with a durable uniform micro-structure were prepared by nested carbon fibers into metal spiral coils cleverly and woven them into a three-dimensional porous material innovatively. The separation purity of the prepared metal–carbon composites on several commonly used industrial lubricating oil emulsions was better than 99.90 % and the flux was greater than 1000 L/m2h. More significantly, computational fluid dynamics was used to establish a simulation model for emulsion separation that revealed the real-time dynamic motion trajectory and volume changes of water droplets. Additionally, even after high-temperature, compression, wear, and corrosion experiments, it still showed dependable separation purity and stable flux. As a result, it has been demonstrated that the proposed metal–carbon composite has a long oil–water separation service life in harsh environments and has great potential for developing efficient and durable emulsion separation materials.

Predictive Value of Dynamic Tumor Volume Changes in Stage III Non-Small Cell Lung Cancer Treated with Chemoradiation and Consolidative Immunotherapy

Concurrent chemoradiation (CRT) followed by Immunotherapy is standard of care in unresectable, locally advanced, non-small cell lung cancer (NSCLC). We hypothesize that on-treatment dynamic changes in tumor volume may predict oncologic outcome in Stage III NSCLC. Stage III NSCLC patients who were treated with definitive CRT of 60 Gy in 30 fractions over 6 weeks with concurrent platinum-based concurrent chemotherapy followed by consolidative immunotherapy were retrospectively reviewed. We manually delineated the gross tumor volumes (GTV) of patients on cone beam computed tomography (CBCT) acquired on day 1, 15, 29 and 43. GTV reduction was quantified as the percent difference in volume on each CBCT as compared to CBCT Day 1. Mid-treatment response (MTR) and End of treatment response (ETR) was defined at day 29 (at 40 Gy) and day 43 (at 60 Gy), respectively. Loco-regional control (LRC) and overall survival (OS) was evaluated by Kaplan-Meier analysis, with log-rank test for groups stratified as per treatment response. Multivariate Cox regression analysis was performed to identify additional prognostic factors. We evaluated 24 consecutively treated patients from 01/2016 to 08/2019, with a median follow-up of 30.5 months. Median age was 69 years (range 51-84). Adenocarcinoma histology was present in 58 % and squamous cell carcinoma in 42% patients. The tumor stage IIIA in 38% and Stage IIIB in 62% patients. All patients received definitive CRT with at least 2 cycles of immunotherapy (median 8 cycles). The median ETR at CBCT43 was 49.5% (range, 1%-84.7%). 1-year cumulative incidence of loco-regional failure (LRF) was 27% versus 10% in patients with ETR <49.5% as compared to patients with greater ETR (p = 0.31). The median MTR at CBCT29 was 32.7% (range, 1%-81%). 1-year cumulative incidence of LRF was 28% versus 9% in patients MTR <32.7% as compared to patients with higher response (p = 0.03). The 3-year actuarial LRC of all patients was 51% which was significantly better in higher MTR (70% vs 30%; p = 0.02, log-rank) as compared to lower MTR. The 3-year actuarial OS for all patients was 45% which was 54% in patients with higher MTR verses 37% in low responders (p = 0.09). On multivariate analysis, age and T-stage were significant factors associated with LRC. Histologic subtype showed no impact on our findings. Stage III NSCLC patients with approximately one-third (33%) reduction of GTV on mid-treatment CBCT during CRT have significantly improved LRC and a trend towards improved OS. This approach may justify early adaptive intensification of RT or application of additional therapies in patients with non-optimal response. Additional large prospective study of CBCT is needed to determine whether treatment can be tailored based on tumor response, to improve outcomes.

Superhydrophobic wire-cotton woven porous material with excellent durability for emulsion separation

Superhydrophobic materials have been extensively investigated for their ability to separate oil/water mixtures, but their fragile durability has limited further development in this field. In this study, a durable superhydrophobic wire-cotton-based material (SWCM) was prepared by weaving metal wire and cotton fiber and modifying it with a mixed poly(vinyl phenol) (PVPh)/1,3-phenylene bisoxazoline (PBO) solution, which exhibits both macro-frame and micro-aperture. The SWCM demonstrates remarkable separation efficiency (greater than99.98 %) for a variety of water-in-oil emulsions using only gravity drive. More importantly, computational fluid dynamics (CFD) simulations were conducted to investigate the separation mechanism of SWCM, revealing dynamic trajectory and volume changes of water droplets in real-time. Moreover, the micro-aperture, protected by the macro-frame, can withstand hundreds of impacts and abrasions and still maintain reliable separation efficiency. Under the encapsulation of micro-apertures, the macro-frame exhibits excellent corrosion resistance and can maintain stable superhydrophobicity even after long-term immersion in different harsh solutions. Due to its excellent durability, the SWCM can maintain a long service life in oil–water separation in complex environments. Therefore, the presented SWCM has great potential in the development of durable and efficient materials for emulsion separation.

Building a Self-Adaptive Protective Layer on Ni-Rich Layered Cathodes to Enhance the Cycle Stability of Lithium-Ion Batteries.

Layered Ni-rich lithium transition metal oxides are promising battery cathodes due to their high specific capacity, but their poor cycling stability due to intergranular cracks in secondary particles restricts their practical applications. Surface engineering is an effective strategy for improving a cathode's cycling stability, but most reported surface coatings cannot adapt to the dynamic volume changes of cathodes. Herein, a self-adaptive polymer (polyrotaxane-co-poly(acrylic acid)) interfacial layer is built on LiNi0.6 Co0.2 Mn0.2 O2 . The polymer layer with a slide-ring structure exhibits high toughness and can withstand the stress caused by particle volume changes, which can prevent the cracking of particles. In addition, the slide-ring polymer acts as a physicochemical barrier that suppresses surface side reactions and alleviates the dissolution of transition metallic ions, which ensures stable cycling performance. Thus, the as-prepared cathode shows significantly improved long-term cycling stability in situations in which cracks may easily occur, especially under high-rate, high-voltage, and high-temperature conditions.

Long-term structural brain changes in adult rats after mild ischaemic stroke.

Preclinical studies of remote degeneration have largely focused on brain changes over the first few days or weeks after stroke. Accumulating evidence suggests that neurodegeneration occurs in other brain regions remote to the site of infarction for months and even years following ischaemic stroke. Brain atrophy appears to be driven by both axonal degeneration and widespread brain inflammation. The evolution and duration of these changes are increasingly being described in human studies, using advanced brain imaging techniques. Here, we sought to investigate long-term structural brain changes in a model of mild focal ischaemic stroke following injection of endothlin-1 in adult Long–Evans rats (n = 14) compared with sham animals (n = 10), over a clinically relevant time-frame of 48 weeks. Serial structural and diffusion-weighted MRI data were used to assess dynamic volume and white matter trajectories. We observed dynamic regional brain volume changes over the 48 weeks, reflecting both normal changes with age in sham animals and neurodegeneration in regions connected to the infarct following ischaemia. Ipsilesional cortical volume loss peaked at 24 weeks but was less prominent at 36 and 48 weeks. We found significantly reduced fractional anisotropy in both ipsi- and contralesional motor cortex and cingulum bundle regions of infarcted rats (P < 0.05) from 4 to 36 weeks, suggesting ongoing white matter degeneration in tracts connected to but distant from the stroke. We conclude that there is evidence of significant cortical atrophy and white matter degeneration up to 48 weeks following infarct, consistent with enduring, pervasive stroke-related degeneration.

Fluorescence exclusion – a rapid, accurate and powerful method for measuring yeast cell volume

Cells exist in an astonishing range of volumes across and within species. However, our understanding of cell size control remains limited, owing in large part to the challenges associated with accurate determination of cell volume. Much of our comprehension of size regulation derives from yeast models, but even for these morphologically stereotypical cells, assessment of cell volume has mostly relied on proxies and extrapolations from two-dimensional measurements. Recently, the fluorescence exclusion method (FXm) was developed to evaluate the size of mammalian cells, but whether it could be applied to smaller cells remained unknown. Using specifically designed microfluidic chips and an improved data analysis pipeline, we show here that FXm reliably detects subtle differences in the volume of fission yeast cells, even for those with altered shapes. Moreover, it allows for the monitoring of dynamic volume changes at the single-cell level with high time resolution. Collectively, our work highlights how the coupling of FXm with yeast genetics will bring new insights into the complex biology of cell growth.

Experimental investigation on the dynamic volume changes of varied-size pores during shale hydration

In order to improve the seepage channels in shale, soaking operation is often conducted after fracturing to carry out full shale hydration by the fracturing fluid. Previous research has mainly focused on the changes in the overall pore volume of shale due to hydration, but there is a lack of understanding on the volume changes of varied-size pores during the hydration process. In this study, a nuclear magnetic resonance (NMR) measurement method was carried out to obtain the size distribution of the pores in the shale in its unaltered state using ethanol as the saturation medium. Subsequently, through experiments, the shale core was saturated with fracturing fluid, and the dynamic changes in the pore size distribution under hydration were monitored using the low-field NMR technique. In addition, the relationships between the type of clay, the salinity of the fracturing fluid and the volume changes of varied-size pore were analyzed. The results of this study indicate that when the shale and fracturing fluid underwent hydration, the increase in the volumes of varied-size pores was concentrated in a certain pore-size area. This pore -size area was related to the type of clay that the shale contained. There was a strong correlation between the mixed-layer illite-smectite content and the increase in the small meso-pore volume. And the same between the illite content and the increase in the micro-pore volume. The saline fracturing fluid had an inhibitory effect on the shale hydration, mainly in the micro-pore domain. The results of this study is significant to optimize the selection of shale gas reservoirs and fracturing fluids for use in soaking measures.

Importance of Gastric Secretion and the Rapid Gastric Emptying of Ingested Water along the Lesser Curvature ("Magenstraße") in Predicting the In Vivo Performance of Liquid Oral Dosage Forms in the Fed State Using a Modeling and Simulation.

The objective of the present study was to develop an in silico model of the stomach for predicting oral drug absorption in fed humans. We focused on a model capable of simulating dynamic fluid volume changes and included a simulated Magenstraße "stomach road," a route along the lesser curvature that often carries fluids rapidly to assess the gastric emptying of drugs. Two types of model liquid drug formulations, liquid-filled soft gelatin capsules (enzalutamide, cyclosporine, and nifedipine) and oral solutions (levofloxacin and fenfluramine), were used. An in silico model was assembled, and simulations were performed using Stella Professional software. The secretion rate of the gastric juice induced by food ingestion was assessed along with the gastric emptying of the ingested water via the Magenstraße in the fed state. The model for the fed state successfully described the in vivo performance of the model drug formulations. These results clearly indicate the importance of including gastric secretion and the kinetics of Magenstraße when predicting the in vivo performance of dosage forms using an in silico modeling and simulation of fed humans. This simulation model should be further optimized to allow for the different physiological mechanisms following the ingestion of different types of meals, as well as modifications for interindividual and intraindividual variabilities in gastrointestinal physiology in the fed state in the future.

Tracking tDCS induced grey matter changes in episodic migraine: a randomized controlled trial

BackgroundOccipital transcranial direct current stimulation (tDCS) is an effective and safe treatment for migraine attack prevention. Structural brain alterations have been found in migraineurs in regions related to pain modulation and perception, including occipital areas. However, whether these structural alterations can be dynamically modulated through tDCS treatment is understudied.ObjectiveTo track longitudinally grey matter volume changes in occipital areas in episodic migraineurs during and up to five months after occipital tDCS treatment in a single-blind, and sham-controlled study.Methods24 episodic migraineurs were randomized to either receive verum or sham occipital tDCS treatment for 28 days. To investigate dynamic grey matter volume changes patients underwent structural MRI at baseline (prior to treatment), 1.5 months and 5.5 months (after completion of treatment). 31 healthy controls were scanned with the same MRI protocol. Morphometry measures assessed rate of changes over time and between groups by means of tensor-based morphometry.ResultsBefore treatment, migraineurs reported 5.6 monthly migraine days on average. A cross-sectional analysis revealed grey matter volume increases in the left lingual gyrus in migraineurs compared to controls. Four weeks of tDCS application led to a reduction of 1.9 migraine days/month and was paralleled by grey matter volume decreases in the left lingual gyrus in the treatment group; its extent overlapping with that seen at baseline.ConclusionThis study shows that migraineurs have increased grey matter volume in the lingual gyrus, which can be modified by tDCS. Tracking structural plasticity in migraineurs provides a potential neuroimaging biomarker for treatment monitoring.Trial registrationClinicalTrials.gov, NCT03237754. Registered 03 August 2017 – retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03237754.

Long-term dynamics of multiple sclerosis iron rim lesions

BackgroundSeveral studies have pointed out that seemingly chronic multiple sclerosis (MS) lesions may also be in inflammatory states. In pathological studies, up to 40% of chronic MS lesions are characterized as “chronic active” or “smoldering” lesions that are characterized by a rim of iron-laden proinflammatory macrophages/microglial cells at the lesion edge with low-grade continuous myelin breakdown. In vivo, these lesions can be visualized as “iron rim lesions” (IRLs) on susceptibility-weighted imaging (SWI). The aim of this study was to investigate the long-term dynamics of IRLs in vivo for a more detailed evolution of dynamic lesion volume changes occurring over time. MethodsWe retrospectively identified patients with MS who were followed for at least 36 months (up to 72 months) and underwent at least an annual MRI on the same 3 Tsystem. Using Voxel-Guided Morphometry (VGM) we investigated regional volume changes within lesions and correlated these findings with SWI for the presence of a characteristic hypointense lesion rim. To estimate tissue damage, apparent diffusion coefficient (ADC) values for every lesion at baseline and follow-up MRIs were determined. ResultsForty-three patients were included in the study. Overall, we identified 302 supratentorial non-confluent MS lesions (52 persistent IRLs, nine transient IRLs, 228 non-IRLs and 13 acute contrast-enhancing lesions). During follow-up, persistent IRLs significantly enlarged, whereas non-IRLs showed a tendency to shrink. At baseline MRI, ADC values were significantly higher in persistent IRLs (1.23 × 10−3 mm/s2) compared to non-IRLs (1.01 × 10−3 mm/s2; p < 0.001), but not compared to transient IRLs (1.06 × 10−3 mm/s2; p = 0.15) and contrast-enhancing lesions (1.15 × 10−3 mm/s2; p = 1.0). During follow-up, ADC values significantly increased more often in persistent IRLs compared to all other lesion types (p < 0.0001). ConclusionsOur long-term data demonstrate that persistent IRLs enlarge during disease duration, whereas non-IRLs show a tendency to shrink. Furthermore, IRLs are associated with sustained tissue damage, supporting the notion that IRLs could represent a new imaging biomarker in MS.

Targeted delivery of pentagalloyl glucose inhibits matrix metalloproteinase activity and preserves elastin in emphysematous lungs

BackgroundElastin degradation has been established as one of the driving factors of emphysema. Elastin-derived peptides (EDPs) are shown to act as a chemoattractant for monocytes. Effectively shielding elastin from elastolytic damage and regenerating lost elastin are two important steps in improving the mechanical function of damaged lungs. Pentagalloyl glucose (PGG) has been shown to preserve elastin in vascular tissues from elastolytic damage in vivo and aid in elastin deposition in vitro.MethodsWe created emphysema by elastase inhalation challenge in mice. Albumin nanoparticles loaded with PGG, conjugated with elastin antibody, were delivered to target degraded elastin in lungs. We investigated matrix metalloproteinase-12 activity and lung damage by measuring dynamic compliance and tidal volume changes.ResultsEx-vivo experiments demonstrated elastin preservation in PGG treated samples compared to controls. Inhaled nanoparticles conjugated with elastin antibody retained for extended periods in lungs. Further, mice treated with PGG nanoparticles showed a significant suppression of MMP-12 activity measured in the lungs. We observed suppression of emphysema in terms of dynamic lung compliance and tidal volume change compared to the control group. The histological examination further confirmed elastin preservation in the lungs.ConclusionThese results demonstrate successful targeted delivery of nanoparticles loaded with PGG to inhibit MMP-12 activity and preserve elastin in the lungs. Such targeted PGG therapy has potential therapeutic use in the management of emphysema.

Biophysical mechanisms of electroconvulsive therapy-induced volume expansion in the medial temporal lobe: A longitudinal in vivo human imaging study

BackgroundElectroconvulsive therapy (ECT) applies electric currents to the brain to induce seizures for therapeutic purposes. ECT increases gray matter (GM) volume, predominantly in the medial temporal lobe (MTL). The contribution of induced seizures to this volume change remains unclear. MethodsT1-weighted structural MRI was acquired from thirty patients with late-life depression (mean age 72.5 ± 7.9 years, 19 female), before and one week after one course of right unilateral ECT. Whole brain voxel-/deformation-/surface-based morphometry analyses were conducted to identify tissue-specific (GM, white matter: WM), and cerebrospinal fluid (CSF) and cerebral morphometry changes following ECT. Whole-brain voxel-wise electric field (EF) strength was estimated to investigate the association of EF distribution and regional brain volume change. The association between percentage volume change in the right MTL and ECT-related parameters (seizure duration, EF, and number of ECT sessions) was investigated using multiple regression. ResultsECT induced widespread GM volume expansion with corresponding contraction in adjacent CSF compartments, and limited WM change. The regional EF was strongly correlated with the distance from the electrodes, but not with regional volume change. The largest volume expansion was identified in the right MTL, and this was correlated with the total seizure duration. ConclusionsRight unilateral ECT induces widespread, bilateral regional volume expansion and contraction, with the largest change in the right MTL. This dynamic volume change cannot be explained by the effect of electrical stimulation alone and is related to the cumulative effect of ECT-induced seizures.

Multi-station LiDAR scanning-based hierarchical features for generation of an allometric stem volume model

Terrestrial laser scanning technology has developed rapidly, and substantial data have been accumulated in dynamic forest monitoring. Point cloud data of standing trees not only provide tree parameters but also show three-dimensional tree structure. Selection of the key parameters from the point cloud data is a prerequisite for volume estimation of standing trees. Our study collected three phases of data over 5 years from Liriodendron chinense plantation forest. A series of the height-related characteristic parameters were extracted from the scanned points of each tree stems, including a proposed new parameter and the height cumulative percentage (Hz % ). The upper diameter accuracy obtained by multi-station scanning is high, and the correlation coefficient with manually measured data is 0.9864. The shape of the upper tree trunk extracted by the point cloud is equivalent to that of the sample trees (height of 10 to 20 m) with points at H25 % and H50 % of the height. These two parameters also show a high correlation with volume. Results show that H25 % can better associated with tree volume, with R2 at 0.951, 0.957, and 0.901 at three stages, respectively. The volume dynamic change calculated by model 2 is linearly correlated with the rate in point cloud restoration, the intercept is −0.081, and the slope is 1.14. Compared with previous researches, the volume model established based on point cloud hierarchical parameters in this study could be used for monitoring the dynamic volume changes in Liriodendron forest. The Hz value extracted from multi-station scanning point cloud data could be used to represent the dynamic forest structure. The results of this study contribute to further development of terrestrial laser scanning-based modeling and estimation methods for individual tree and forest growth, thereby improving the accuracy of forest inventories estimation and providing better tools for decision-making processes.