Macroscopic Volume Research Articles

Dislocation‐Induced Local and Global Photoconductivity Enhancement and Mechanisms in Iron‐Doped SrTiO3

AbstractDislocations have a tremendous potential to alter band structure and transport properties. However, their impact on the optoelectronic properties of metal oxides is not thoroughly studied. This is mostly due to the early work on classical semiconductors, where dislocations are found to have detrimental effects. In this study, a simple method is developed to introduce a high density of dislocations over a large macroscopic volume of Fe‐doped SrTiO3 single crystals. As a result, the photoconductivity revealed by static and dynamic measurements increases by at least one order of magnitude. A detailed analysis based on photo‐Hall, spectral photoresponsivity, time‐resolved photocurrent, and conductive AFM, focusing on the quantum paraelectric state of SrTiO3, is presented to shed light on the possible mechanisms behind higher generated photocurrent. These findings indicate that the increased photoconductivity results from a higher charge carrier generation rate due to new energy states induced by dislocations, possibly accompanied by an enhancement of electron effective mass.

Optimization of laser engraving labeling conditions using response surface methodology and its impact on quality characteristics of dragon fruit (Hylocereus undatus) peels

Establishing a traceability system ensures safety and improves food quality and transparency. A reliable traceability system is in high demand, especially for fresh produce like fruits and vegetables to control various food-borne outbreaks. They are conventionally labeled with plastic/paper stickers, which are not reliable, as they are easy to remove and counterfeit. Laser engraving is a novel technology that provides anti-counterfeiting and ecologically friendly labels. In the current study, a laser system was optimized for etching alphanumeric codes on dragon fruit peel. The input variables for laser engraving were input power (14.3–18.2 W), air compressor pressure (2.8–5.6 kPa) and marking speed (30–200 mm/s), and the response variables involving visibility of mark, depth of penetration, damage to the skin and shrinkage of the peel have been investigated. At the optimized conditions of 15.39 W input power, 3.27 kPa compressor pressure, and 161 mm/s marking speed, the label was clearly visible with 0.31 mm depth of penetration, 2.28 kPa skin strength, 0.22 % weight loss and 1.5 % shrinkage in macroscopic volume. Laser marking reached only 15 % depth, affecting 8 % of the total surface area and not even impacting the edible pulp portion of dragon fruit. The phytochemical and FTIR analysis showed no substantial effect on the laser-treated peel.

Free-water imaging in subcortical gray matter in schizophrenia patients with persistent auditory verbal hallucinations

Subcortical gray matter (SGM) is increasingly linked to the pathophysiology of schizophrenia, specifically auditory verbal hallucinations (AVHs). However, few studies have been conducted on the role of extracellular free-water (FW) and white matter microstructural abnormalities in AVHs within the SGM using the free water elimination technique. We conducted a comprehensive investigation of macroscopic volume, FW, and white matter microstructure in the SGM of 60 schizophrenia patients with persistent AVHs (p-AVH), 36 patients no AVH history (n-AVH), and 43 healthy control participants (HC). No macroscopic volume abnormalities were found in the p-AVH or n-AVH groups. However, abnormalities in both FW and microstructures were detected in multiple SGM structures of individuals with schizophrenia. Importantly, unlike the n-AVH group, the p-AVH group exhibited FW and microstructure abnormalities in the bilateral caudate that correlated with AVH severity. Our findings suggest that regardless of the presence of AVHs, FW and microstructure abnormalities in the SGM are more pronounced than macroscopic volume abnormalities in patients with schizophrenia. The bilateral caudate may be a key factor in the mechanisms underlying AVHs. Additionally, normal FW and microstructure in the bilateral caudate may be a notable characteristic of n-AVH patients.

Synthesis and application of an amphiphilic polymer bearing benzimidazole and long alkyl benzene sulfonamide groups for enhancing heavy oil recovery

Using acrylamide (AM), sulfobetaine methacrylate (SBMA), glycidyl methacrylate (GMA), and N,N-diallyl-4-dodecyl benzene sulfonamide (DBDAP) with long carbon chain and benzene ring as monomers, polymer P(ASGD) was prepared by free-radical micellar copolymerization. Benzimidazole is a heterocyclic aromatic organic compound and it shows similar polarity and structure with asphaltene, by undergoing a ring open reaction between epoxy groups on polymer P(ASGD) and amino groups on 2-aminobenzimidazole(AMZ), a novel amphiphilic polymer named HOVR was obtained. The chemical structure and thermodynamic stability of HOVR were evaluated using FT-IR, 1H NMR and TGA analyses, respectively. Meanwhile, polymer P(ASD) without benzimidazole group, P(ASG) without benzene sulfonamide group, and P(AS) without these two functional groups were synthesized and compared with the properties of HOVR. The potential of polymers for enhancing heavy oil recovery including rheological properties, interfacial activity, wettability alternation, and viscosity reduction ability of heavy oil were studied. In the presence of HOVR, hydrogen bonding and π-π stacking interactions can be formed between HOVR and asphaltene molecules, then the overlapping and stacking structure of asphaltene aggregates collapsed, coupled with the reduction of IFT, the heavy oil was emulsified to form O/W emulsion with small size and uniform distribution, so the viscosity reduction rate (VRR) achieved 95.1 % for 2000 mg/L HOVR at 60 °C and oil/water ratio of 5:5, while the VRR of P(AS), P(ASD) and P(ASG) is 63.5 %, 84.2 % and 83.4 %. Meanwhile, the synergistic effects of benzimidazole and long alkyl benzene sulfonamide enabled HOVR to possess superior ability in increasing aqueous phase viscosity and shifting oil-wetting solid surface towards water-wetting compared with other three polymers. The reversal of wettability can convert capillary resistance into driving force during the displacement process. The oil displacement experiments in core-flooding tests indicated that the cumulative recovery rate was increased by 19.2 %, 11.2 %, 10.2 % and 7.7 % for polymer HOVR, P(ASG), P(ASD) and P(AS) with concentration of 2000 mg/L. The superior efficiency of heavy oil displacement by HOVR is attributed to the enhancements in macroscopic sweep volume and microscopic displacement efficiency, as confirmed by the glass-etched micro-model experiment, and NMR test conducted during the oil displacement process.

Study on the circumferential tensile behavior of SiCf/SiC composite cladding tubes across a broad temperature range: High temperature interface enhancement effect from a cross-scale perspective

In nuclear reactors, Silicon carbide fiber reinforced silicon carbide matrix (SiCf/SiC CMC) cladding tubes are susceptible to circumferential damage due to internal gas pressure expansion. However, due to its complex spatial fiber winding structure, investigating circumferential tensile failure under extreme temperatures is challenging. Therefore, using cross-scale methods and experiments from 20 °C to 1100 °C, this study examined circumferential damage at macro, micro, and nanoscale levels. Specifically, as the temperature increases, the material still maintains excellent structural stability; at 1100 °C, the critical damage load decreases by 72.5 % and the critical displacement increases by 197.1 %.The " interface enhancement effect" between the fibers and matrix results in a relatively smooth fracture morphology. At the macroscopic level, morphology evolution reflects the transition from brittle to pseudo-plastic behavior. Additionally, based on the principle of minimum potential energy and the theory of semi-geodesics, the complex macroscopic structure and microscopic Representative Volume Element (RVE) model was reconstructed. The findings show the numerical model accurately represents the circumferential damage of SiCf/SiC CMC under extreme temperatures. Simultaneously, at the molecular level, the interfacial strength at high temperature is 7.5 % higher than that at ordinary temperature, resulting in a distinct adhesive interaction between matrix and fibers. This study opens up new avenues for the fundamental theoretical research of such ceramic matrix materials. interface enhancement effect.

Insights into the Thermal Expansion of Amorphous Polymers.

We investigated the thermal expansion of amorphous polystyrene (PS) and poly(methyl methacrylate) (PMMA) homopolymers using the temperature dependence of spatial electron-density correlations. The strong and broad X-ray interference maxima arising from inter- and intramolecular correlation distances were distinct, maintaining their shape during the heating of the samples to 250 °C. Three maxima characteristic of electron density correlations between the backbones, substituents along the chain, and repeat-units were observed. A remarkable temperature dependence was identified in the largest correlation distances arising from the intermolecular interactions. Based on the temperature dependence of the correlation distances, the coefficients of molecular expansion were very close to the coefficients of thermal expansion. This study provides a simple yet accurate way to correlate macroscopic volume expansions with the molecular expansion obtained from wide-angle X-ray scattering (WAXS) data.

A multi-level-variable correlated mechanistic model system for irradiation-induced multi-scale volume growths of U-10Mo/Zr dispersion nuclear fuels

Irradiation-induced volumetric deformations in dispersion nuclear fuels arouse a critical concern in nuclear fuel design. Utilizing the concepts from mesomechanics and homogenization, a multi-level-variable correlated mechanistic model system called the Dispersion Fuel Swelling Analysis Model System (DFSAMS) is developed for the irradiation-induced multi-scale volume growths of U-10Mo/Zr dispersion nuclear fuels. These models could directly correlate the macroscopic irradiation-induced volume growth strain with the dynamically varying multi-level information, including the obtained particle volume fractions, the current porosities of recrystallized zones of fuel grains, the macroscale porosities of fuel particles, the average numbers of fission gas atoms within fuel bubbles, the average bubble pressures and the macroscale pressures of fuel particles related to the macroscale hydrostatic pressures of dispersion fuels. The obtained theoretical results align favorably with finite element predictions and a diverse range of experimental data, demonstrating the effectiveness of the newly developed model system. It is indicated that: (1) the irradiation creep performance of the Zr matrix becomes the predominant factor influencing the macroscale volume growth deformations of U-10Mo/Zr dispersion fuels, due to the differed resistance to volumetric deformations of U-10Mo particles; (2) the as-fabricated bubbles of fuel particles will gradually decrease in size under the macroscale hydrostatic pressures due to the irradiation creep deformations occurring in the surrounding solid skeleton, contributing negatively to the macroscale volumetric expansion of U-10Mo/Zr dispersion fuels, especially in cases with higher initial porosity. The important theoretical models are supplied here for efficient numerical simulation of the irradiation-induced thermal-mechanical coupling behaviors in U-10Mo/Zr dispersion fuel elements.

Water and brain function: effects of hydration status on neurostimulation with transcranial magnetic stimulation.

Neurostimulation/neurorecording are tools to study, diagnose, and treat neurological/psychiatric conditions. Both techniques depend on volume conduction between scalp and excitable brain tissue. Here, we examine how neurostimulation with transcranial magnetic stimulation (TMS) is affected by hydration status, a physiological variable that can influence the volume of fluid spaces/cells, excitability, and cellular/global brain functioning. Normal healthy adult participants (32, 9 males) had common motor TMS measures taken in a repeated-measures design from dehydrated (12-h overnight fast/thirst) and rehydrated (identical dehydration protocol followed by rehydration with 1 L water in 1 h) testing days. The target region was left primary motor cortex hand area. Response at the target muscle was recorded with electromyography. Urinalysis confirmed hydration status. Motor hotspot shifted in half of participants. Motor threshold decreased in rehydration, indicating increased excitability. Even after redosing/relocalizing TMS to the new threshold/hotspot, rehydration still showed evidence of increased excitability: recruitment curve measures generally shifted upward and the glutamate-dependent paired-pulse protocol, short intracortical facilitation (SICF), was increased. Short intracortical inhibition (SICI), long intracortical inhibition (LICI), long intracortical facilitation (LICF), and cortical silent period (CSP) were relatively unaffected. The hydration perturbations were mild/subclinical based on the magnitude/speed and urinalysis. Motor TMS measures showed evidence of expected physiological changes of osmotic challenges. Rehydration showed signs of macroscopic and microscopic volume changes including decreased scalp-cortex distance (brain closer to stimulator) and astrocyte swelling-induced glutamate release. Hydration may be a source of variability affecting any techniques dependent on brain volumes/volume conduction. These concepts are important for researchers/clinicians using such techniques or dealing with the wide variety of disease processes involving water balance.NEW & NOTEWORTHY Hydration status can affect brain volumes and excitability, which should affect techniques dependent on electrical volume conduction, including neurostimulation/recording. We test the previously unknown effects of hydration on neurostimulation with TMS and briefly review relevant physiology of hydration. Rehydration showed lower motor threshold, shifted motor hotspot, and generally larger responses even after compensating for threshold/hotspot changes. This is important for clinical and research applications of neurostimulation/neurorecording and the many clinical disorders related to water balance.

Characteristics of liver volume and pathological changes with different stages of liver fibrosis in chronic liver disease

Objective: To measure the overall and lobulated volume of the liver with different degrees of liver fibrosis and to further observe pathological changes such as liver microvasculature, hepatocyte apoptosis, and regeneration in order to understand the macroscopic volume changes of the liver during liver fibrosis and its relationship with liver tissue microscopic pathology in patients with chronic liver disease. Methods: 53 patients with chronic hepatitis B, alcoholic fatty liver disease, autoimmune liver disease, nonalcoholic fatty liver disease, and drug-induced chronic liver disease who underwent both liver biopsy tissue and abdominal magnetic resonance imaging were collected. Patients were divided into early (F1-2), middle (F3-4), and late (F5-6) in accordance with the Ishak fibrosis stage and Masson stain. The liver and spleen volumes were measured using ITK-SNAP software. CD31 immunohistochemical staining was used to reflect intrahepatic angiogenesis. Ki67 and HNF-4α multiplex immunohistochemical staining were used to reflect hepatocyte regeneration. GS staining was used to determine parenchymal extinction lesions. TUNEL staining was used to observe hepatocyte apoptosis. Spearman correlation analysis was used to analyze the relationship between liver volume changes and liver histopathological changes. Results: As liver fibrosis progressed, the total liver volume and right lobe liver volume gradually decreased (P<0.05), while the spleen volume gradually increased (P<0.05). The expression of CD31 and GS gradually increased (P<0.05), and the expression of Ki67 first increased and then decreased (P<0.05). The positivity rate of CD31 was negatively correlated with the right lobe liver volume (r=-0.609, P<0.001) and the total liver volume (r=-0.363, P=0.017). The positivity rate of Ki67 was positively correlated with the right lobe liver volume (r=0.423, P=0.018), while the positivity rate of apoptotic cells was significantly negatively correlated with the total liver volume (r=-0.860, P<0.001). The positivity rate of GS was negatively correlated with the right lobe liver volume (r=-0.440, P=0.002), and the number of PELs was negatively correlated with RV (r=-0.476, P=0.013). The CD31 positive staining area was negatively correlated with the Ki67 positive staining area(r=-0.511, P=0.009). Conclusion: As liver fibrosis progresses, patients with chronic liver disease have a depletion in total liver volume and right lobe liver volume, and this is mainly in correlation with fewer liver cells and liver tissue microvasculature disorders.

In Situ Magnetometry of Iron in Human Dopaminergic Neurons Using Superresolution MRI and Ion-Beam Microscopy

Paramagnetic transition metals play a crucial role as cofactors in various cellular catalytic processes. However, their high concentrations in reactive oxidation states can induce oxidative stress, resulting in cell dysfunction or death. Hence, it is vital to have methods to monitor metal concentrations and paramagnetic properties in cells for medicine and cell biology. Here we present a novel multimodal method for in-cell magnetometry enabling direct measurement of metal magnetic properties within individual cells in tissue, without prior isolation and at room temperature. Individual cell magnetic moments are measured using superresolution magnetic resonance imaging (MRI) microscopy at 9.4 T by detecting microscopic magnetic-field perturbations around the cells. The cellular metal content is quantified using ion-beam microscopy or synchrotron micro-x-ray fluorescence for the same cells. The metal magnetic susceptibility at 9.4 T is then obtained from the slope of the cell magnetic moments’ dependence on cell metal content. To estimate the susceptibility at lower fields, multifield MR relaxometry and biophysical modeling are employed, extrapolating the 9.4-T susceptibility values to fields as low as 3 T. We apply the new method to determine the susceptibility of iron accumulated in human dopaminergic neurons inside neuromelanin, the by-product of dopamine synthesis. The susceptibility of iron in neuromelanin is measured to be χρ=(2.98±0.19)×10−6 m3/kg providing unique insights into the biochemistry of iron inside dopaminergic neurons. The obtained value reveals a predominant monoatomic low-affinity iron-binding site within neuromelanin, indicating a higher neurotoxicity of iron than previously suggested. Furthermore, the measured susceptibility value establishes a quantitative relationship between cellular iron concentration and iron-sensitive MRI parameters, which can be noninvasively measured . This breakthrough paves the way for the detection of dopaminergic neuron density and iron load, requiring a standard clinical MRI scanner only. It promises to facilitate early diagnosis of Parkinson’s disease. In conclusion, our presented novel method enables the direct measurements of magnetic properties of paramagnetic metals within single cells with high sensitivity and across large cell groups within a macroscopic volume, providing invaluable information about the cellular biology of metals. Published by the American Physical Society 2024

The Value of PET/CT in Particle Therapy Planning of Various Tumors with SSTR2 Receptor Expression: Comparative Interobserver Study.

The overexpression of somatostatin receptor type 2 (SSTR2) is a property of various tumor types. Hybrid imaging utilizing [68Ga]1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra-acetic acid (DOTA) may improve the differentiation between tumor and healthy tissue. We conducted an experimental study on 47 anonymized patient cases including 30 meningiomas, 12 PitNET and 5 SBPGL. Four independent observers were instructed to contour the macroscopic tumor volume on planning MRI and then reassess their volumes with the additional information from DOTA-PET/CT. The conformity between observers and reference volumes was assessed. In total, 46 cases (97.9%) were DOTA-avid and included in the final analysis. In eight cases, PET/CT additional tumor volume was identified that was not detected by MRI; these PET/CT findings were potentially critical for the treatment plan in four cases. For meningiomas, the interobserver and observer to reference volume conformity indices were higher with PET/CT. For PitNET, the volumes had higher conformity between observers with MRI. With regard to SBGDL, no significant trend towards conformity with the addition of PET/CT information was observed. DOTA PET/CT supports accurate tumor recognition in meningioma and PitNET and is recommended in SSTR2-expressing tumors planned for treatment with highly conformal radiation.

Muscle-invasive bladder cancer in elderly and frail people: Is hypofractionated radiotherapy a feasible approach when no other local options are available?

The study aims to report the feasibility and safety of palliative hypofractionated radiotherapy targeting macroscopic bladder tumors in a monocentric cohort of frail and elderly bladder cancer patients not eligible for curative treatments. Patients who underwent hypofractionated radiotherapy to the gross disease or to the tumor bed after transurethral resection of bladder tumor from 2017 to 2021 at the European Institute of Oncology IRCCS, were retrospectively considered. Schedules of treatment were 30 and 25 Gy in 5 fractions (both every other day, and consecutive days). Treatment response was evaluated with radiological investigation and/or cystoscopy. Toxicity assessment was carried out according to RTOG/EORTC v2.0 criteria. A total of 16 patients were included in the study, of these 11 received hypofractionated radiotherapy on the macroscopic target volume and five on the tumor bed after transurethral resection of bladder tumor. No grade (G) >2 acute toxicities were described after treatment for both groups. Only one patient in the group receiving radiotherapy on the macroscopic disease reported G4 GU late toxicity. Ten patients had available follow-up status (median FU time 18 months), of them six had complete response, one had stable disease, and three had progression of disease. The overall response rate and disease control rate were 60% and 70%, respectively. Our preliminary data demonstrate that palliative hypofractionated radiotherapy for bladder cancer in a frail and elderly population is technically feasible, with an acceptable toxicity profile. These outcomes emphasize the potential of this approach in a non-radical setting and could help to provide more solid indications in this underrepresented setting of patients.

A constitutive model of solid propellants considering aging and confinement pressure

AbstractAging during storage and confinement pressure during launch are the two major loading conditions that affect the integrity of solid rocket motors. In comparison to other component materials, solid propellants, as highly filled composites, have a low modulus and fracture toughness and are therefore common sources of failure. The key to improving the integrity of the solid rocket motor is in assessing the health of the solid propellants during storage or launch. To address this issue, we revised the previous model for the progressive damage viscoelasticity of solid propellants to include the effect of chemical aging during storage and the influence of confinement pressure during launch. Specifically, the increase in relaxation time due to aging and the nonequilibrium volume dilatation characteristics under triaxial tension and compression of solid propellants have been considered. To validate the developed model, standard relaxation tests and uniaxial tensile tests on solid propellants without aging were used to calibrate the model parameters. Furthermore, the model was validated by comparison with uniaxial tensile tests under confined pressure after aging and well predicts the aging temperature/time‐dependent mechanical responses of solid propellants. After validation, the developed model was used to study the influence of confinement pressure on microscopic damage evolution and macroscopic volume expansion. Overall, the developed model can be used for the analysis of the integrity of the solid rocket motor after the aging process.

Quantum sensors in diamonds for magnetic resonance spectroscopy: Current applications and future prospects

Nuclear magnetic resonance (NMR) and electron spin resonance (ESR) methods are indispensable techniques that utilize the spin of particles to probe matter, with applications in various disciplines, including fundamental physics, chemistry, biology, and medicine. Despite their versatility, the technique's sensitivity, particularly for NMR, is intrinsically low, which typically limits the detection of magnetic resonance (MR) signals to macroscopic sample volumes. In recent years, atom-sized magnetic field quantum sensors based on nitrogen-vacancy (NV) centers in diamond paved the way to detect MR signals at the micro- and nanoscale, even down to a single spin. In this perspective, we offer an overview of the most promising directions in which this evolving technology is developing. Significant advancements are anticipated in the life sciences, including applications in single molecule and cell studies, lab-on-a-chip analytics, and the detection of radicals or ions. Similarly, NV-MR is expected to have a substantial impact on various areas in the materials research, such as surface science, catalysis, 2D materials, thin films, materials under extreme conditions, and quantum technologies.

Eco-friendly calcium alginate microspheres enable enhanced profile control and oil displacement

Polymer microspheres (PMs), such as polyacrylamide, have been widely applied for enhanced oil recovery (EOR), yet with environmental concerns. Here, we report a microfluid displacement technology containing a bio-based eco-friendly material, i.e., calcium alginate (CaAlg) microspheres for EOR. Two dominant mechanisms responsible for EOR over CaAlg fluid have been verified, including the microscopic oil displacement efficacy augmented by regulating capillary force (determined by the joint action of interfacial tension and wettability between different phases) and macroscopic sweep volume increment through profile control and mobility ratio reduction. This comprehensive effectiveness can be further impacted when the CaAlg microsphere is embellished ulteriorly by using appropriate amount of sodium dodecyl sulfonate (SDS). The core flooding and nuclear magnetic resonance (NMR) tests demonstrate that CaAlg-SDS microsphere can balance the interphase property regulation (wettability alteration and IFT reduction) and rheology properties, enabling simultaneous profile control and oil displacement. Excessive introduction of SDS will have a negative impact on rheological properties, which is not favored for EOR. Our results show that the involvement of 4-mM SDS will provide the best behavior, with an EOR rate of 34.38%. This cost-effective and environmentally-friendly bio-microsphere-based microfluidic displacement technology is expected to achieve “green” oil recovery in future oilfield exploitation.

Modelling the hydration of cement ‐ Does chemical shrinkage influence autogenous self‐healing?

AbstractAutogenous self‐healing of cracks in water retaining concrete structures is included in Eurocode 1992‐3 as a possible measure to heal cracks up to a width of 200 μm without additional repair. Water flow through the crack leads to the closure of the fracture, mainly due to CaCO3 precipitation. However, despite standardization, the healing effect seems to be random in practice. This study uses thermodynamic modelling of cement hydration to examine how the timing of crack formation affects crack widening or closure due to chemical shrinkage or swelling and discusses the implications for autogenous self‐healing. It is found that the exact timing of early‐age crack formation can lead to crack widening or closure in the range of a few micrometres. This effect is most prominent for cracking within the first two days of curing and dependents on the cement type, the fraction of inert material in the mix design and the amount of shrinkage that translates into a macroscopic volume reduction. However, it is concluded that other more dominant factors must be at play leading to the discrepancy between laboratory results and the unpredictable healing efficiency observed in practice.

Study on Deformation Mechanism of Saturated Sand Based on Discrete Element Method

Based on the discrete element program (particle flow code PFC3D), the effects of the initial void ratio on the macroscopic and microscopic mechanical responses, phase transition state and critical state characteristics of saturated sand are systematically investigated in drained tests. The phenomenon that saturated sand enters the critical state earlier than the laboratory macroscopic results is revealed from the microscopic point of view. The results show that the phase transition state of the saturated sand can be reflected by the extreme values of void ratio, sliding ratio, suspended particle ratio and mechanical coordination number. Compared to the macroscopic parameters stress ratio and volume strain, the microscopic parameters can earlier reveal the critical state of saturated sand. The saturated sands with different initial void ratios have the same anisotropy component at the critical state. At the phase transition state, only the weight of normal contact force anisotropy is in the peak state. During the development of saturated sand from shrinkage to dilatancy, the velocity of particle motion on the diagonal 45° shear surface of the sample is intense and the particle motion is dominated by rotation. The above conclusions expand the current understanding of the deformation mechanism at the phase transition state and critical state of the soil.

Assessing keloid treatment efficacy: a comparison of intralesional umbilical-cord mesenchymal stem cells, their conditioned medium, and triamcinolone acetonide injection through macroscopic and microscopic examination

Link Video Abstract: https://youtu.be/NAnsqP7dPd0 Background: Current keloid treatment involves intralesional injection of triamcinolone acetonide (TA), which, despite its usage, is associated with high recurrence rates and adverse effects. Mesenchymal stem cells (MSCs) exhibit potent proliferative abilities and can curb fibroblast activity and proliferation within keloids. It is now known that umbilical cord mesenchymal stem cells (UC-MSCs) have been shown to have greater proliferative potential than bone marrow-derived MSCs (BM-MSCs), and other advantages of UC-MSCs include being easily accessible and less immunogenic. To assess the viability of administering umbilical cord MSC (UC-MSC) and its conditioned medium (UC-CM) via intralesional injection compared to TA in reducing macroscopic keloid volume and type 1:3 collagen ratio. Methods: This randomized controlled trial enrolled twenty-four keloid patients by consecutive sampling. Eligible patients were required to have keloids on the chest, back, abdomen, or extremities. Patients with hypertrophic scars, a history of kidney failure, hypertension, blood disorders, malignancy, pregnancy, breastfeeding, or keloid treatment were excluded. Sociodemographic data, keloid size, and tissue biopsies were collected during scheduled visits. Bivariate analyses applied were considered significant at a p-value of &lt;0.05. Results: The study revealed that the most significant decrease in macroscopic volume occurred within the UC-MSC group, followed by the UC-CM group, and then the TA group (UC-MSC: 50.24% ± 3.58%; UC-CM: 43.97% ± 3.04%; TA: 33.53% ± 2.64; p = 0.004. The UC-CM group exhibited the most substantial decrease in the type 1:3 collagen ratios (4.80±0.26), with UC-MSC (4.60(4.15-8.05)) and TA (3.96(1.63-4.14)) following in sequence (p=0.002). Conclusion: The findings of this study indicate that the use of UC-MSC and UC-CM exhibits promising superiority over TA in terms of reducing macroscopic keloid volume and type 1:3 collagen ratio.

The Influence of Overburden Stress and Molding Water Content on the Microstructure of Remolded Loess

This study aims to reveal the mechanisms of the microstructural evolution of remolded loess under different molding water contents and overburden stresses. Utilizing L6 loess from Yan’an, remolded soil specimens were fabricated under various pressures and moisture contents, followed by conducting one-dimensional consolidation tests. The macroscopic porosity, pore size distribution curves (PSD), and microstructure of these remolded loess samples were examined. Experimental findings indicate that an increase in molding water content leads to an augmentation in macroscopic pore volume and elongated pore shapes, concurrently exerting substantial influence on the primary pore size and pore volume of both macropores (&gt;0.4 μm) and minipores (0.4–4 μm), with minimal impact on micropores (&lt;0.4 μm). The escalation of overburden stress solely contributes to the reduction in pore size and pore volume of macropores. Variations in the Menger fractal dimension occur only beyond the optimal water content, while overburden stress exhibits a minimal effect on the Menger fractal dimension. Furthermore, remolded loess exhibited a certain yield stress, and when the overburden stress was lower than the yield stress, there was almost no change in various types of pores. Finally, a microstructural evolution model of remolded loess under different molding water contents and overburden stresses was proposed. These findings are expected to provide new insights into the microstructural evolution and deformation mechanisms of loess in high embankment construction sites.

VAM: An End-to-End Simulator for Time Series Regression and Temporal Link Prediction in Social Media Networks

We present a machine-learning-driven end-to-end simulator, called the <i>Volume-Audience-Match</i> (VAM) simulator. VAM&#x2019;s purpose is to simulate future phenomena related to various topics of discussion in social media networks. We focus our attention on the social media platform, Twitter, due to its abundant use in today&#x2019;s world. VAM was applied to do time series forecasting to predict the future: 1) number of total activities; 2) number of active old users; and 3) number of newly active users over the span of 24 hours from the start time of prediction. VAM then used these macroscopic volume predictions (VPs) to perform user link predictions. A user&#x2013;user edge was assigned to each of the activities in the 24 future time steps. We report that VAM outperformed multiple baseline models in the time series task, which were the auto-regressive integrated moving average (ARIMA), auto regressive moving average (ARMA), auto regressive (AR), moving average (MA), Persistence Baseline, and state-of-the-art tNodeEmbed models. Furthermore, we show that VAM outperformed the Persistence Baseline and tNodeEmbed models used for the user-assignment tasks. Finally, it is also shown that using Reddit activity data improves prediction accuracy.