Initial Volume Research Articles

Predictive factors for the outcome of radioiodine therapy in patients with benign thyroid diseases.

Radioiodine therapy (RIT) of benign thyroid diseases is an established therapy. This study aimed to identify factors predictive for outcome in patients with non-toxic goiter (NTG), unifocal (UFA), multifocal (MUFA) or diffuse autonomy (DISA) and Graves' disease (GD). Retrospective analysis of 205 patients with benign thyroid disease (54 NTG, 46 MUFA, 24 DISA, 26 UFA, 55 GD) who underwent RIT. Follow up time was 12 months for determining treatment outcome. The type of disease was predictive for volume reduction after 12 months (NTS 66%, DISA 67%, MUFA 58%, UFA 51%, GD 71%, p<0.001) and post-treatment hypothyroidism (NTS 48%, DISA 33%, MUFA 15%, UFA 15%, p=0.006). Initial volume, intra-therapeutic uptake and intra-therapeutic half-life were independent prognostic factors for volume reduction 12 months after RIT. In patients with NTG, UFA, MUFA, DISA post-treatment hypothyroidism was significantly correlated with extent of volume reduction 12 months after RIT, achieved dose, higher pre-therapeutic TSH values and younger age. Two different strategies for pre-therapeutic dosimetry used in MUFA showed no differences regarding the therapeutic outcome. In GD, effective half-life, initial volume and Graves' ophthalmopathy were predictive for treatment failure. Reduction of thyroid volume and the percentage of hypothyroid patients one year after RIT was primarily dependent on the type of disease. In MUFA and DISA we could identify volume reduction after 3 months as a reliable predictor for hypothyroidism while in patients with GD a short intra-therapeutic half-life, a large pre-therapeutic volume and active Graves' ophtalmopathy were relevant predictors for treatment failure suggesting an intensified follow-up scheme in these patients.

Short communication: ROS production and mitochondrial membrane potential in hemocytes of marine bivalves, Mytilus galloprovincialis and Magallana gigas, under hypoosmotic stress.

Bivalve mollusks that inhabit low-depth coastal and estuarine areas frequently experience osmotic stress that may be also associated with alterations of antioxidant enzyme activities and markers of oxidative stress. Mitochondria are a major source of reactive oxygen species (ROS) in eucaryotic cells. Overpoduction of ROS induces oxidative stress leading to a damage of intracellular compartments and cell death. In euryhaline bivalves, information concerning cellular ROS production upon osmotic stress and changes in mitochondrial membrane potential is scarce. The present study investigates osmotic stability and hemocytes` regulatory volume decrease (RVD) of Mediterranean mussel (Mytilus galloprovincialis) and the Pacific oyster (Magallana gigas). We also studied dynamic changes in intracellular ROS levels and mitochondrial membrane potential in hemocytes undergoing the RVD response following hypoosmotic swelling. Our data revealed that osmotic stability of mussel and oyster hemocytes did not significantly differ. Loss of environmental osmolarity from 460.0±2.0mOsml-1 to 216.0±4.0mOsml-1 resulted in an increase of hemocyte volume by 60% of the initial cellular volume in mussels and by 28% in oysters. After rapid hypoosmotic swelling hemocytes of both species demonstrated the RVD response. At the end of 60min exposure to hypoosmotic environment, hemocyte volume significantly decreased in both species by 10-12% compared to the maximal hemocyte volume. Hypoosmotic shock induced an increase of mitochondrial membrane potential in hemocytes of mussels and oysters. In mussels, increased mitochondrial membrane potential was accompanied with decreased ROS levels in hemocytes, whereas oyster hemocytes showed enhanced ROS production.

Impact of alteration corridors on karst reservoir organisation and evolution of groundwater flow path: An example from the southern border of the Larzac Causse, southern France

All the features of karstic reservoirs result from the chemical and/or mechanical erosion of an initial rock volume, which modifies the initial petrophysical properties (i.e., porosity and permeability). The spatial distribution and organisation of the karst system in a carbonate massif are often overlooked in studies on karst hydrological functioning. However, these parameters are key to understand and accurately model dynamic flow. This contribution aims at characterising the nature and impact of alteration corridors on the organisation and evolution of the karstic reservoir and its present-day functioning. We focus on characterising the specific impact of the late onset of pocket valley regressive erosion on the organisation of the present-day drainage system. We used a 3D approach to correlate field observations on the surface and in caves, with remote sensing. The expression of alteration corridors is analysed in a 40 km2 area on the southern border of the Larzac Causse. This Jurassic carbonate massif is affected over its entire thickness by a network of vertically elongated alteration corridors containing dissolution-collapse breccia, mainly oriented in a N-S direction. Ghost-rock karstification played a significant part in the karstic reservoir structure and evolution. Alteration corridors result from the in-situ dissolution of the bedrock along an initial jointing pattern. The dissolution-collapse breccia corridors correspond to ghost-rock corridors selectively emptied of their alterite, under the effect of a hydraulic gradient. The vertically elongated structure of alteration corridors that cross-cut the Jurassic sequence enables fluid circulation from an upper to a lower aquifer, which were initially separated by a Toarcian marly seal unit. The subsequent initiation of pocket valleys led to the rapid evacuation of the residual alterite contained in ghost-rock corridors, under the influence of gravity. These alteration corridors determine the position of present-day pocket valley springs and enhance the regressive erosion dynamics, that progressively capture a north-east flowing watershed (Vis River). Finally, residual alterites are evacuated below the overflow spring altitude during high-flow events by flooding/dewatering of galleries. Such mechanisms of alterite evacuation provide insight into i) the part of the karstic reservoir that is connected to the spring, and ii) the dynamics of the associated flows. This study suggests that corridor networks constitute a substantial volume of porous and permeable materials that plays a major role in the present-day groundwater flow path. Such features should be considered valuable drilling targets for water exploration when located below the piezometric level.

Hindering the unlimited proliferation of tumor cells synergizes with destroying tumor blood vessels for effective cancer treatment.

The rational combination of chemotherapy drugs can improve the curative effect of cancer treatment. As two early recognized tumor hallmarks, the limitless replicative potential of tumor cells is essential for the development of their malignant growth state, and sustained angiogenesis is a prerequisite to the rapid growth of tumors. Based on this, we propose a combination therapy that hinders the unlimited proliferation of tumor cells and destroys tumor blood vessels. Herein, 7-ethyl-10-hydroxycamptothecin (SN38), a typical topoisomerase I inhibitor, was bonded to poly(L-glutamic acid) (PLG) to prepare the nanodrug SN38-NPs, which hinders the unlimited proliferation of tumor cells. A poly(L-glutamic acid)-combretastatin A4 conjugate (CA4-NPs), a representative vascular disrupting agent (VDA), was used to selectively disrupt the tumor blood vessels, cutting off the necessary nutrients and oxygen for the proliferation of tumor cells. In the 4T1 tumor model with an initial volume of about 400 mm3, the combined treatment of SN38-NPs and CA4-NPs showed an excellent cancer treatment effect with a tumor suppression rate of 94.3% and a synergistic interaction (Q = 1.25). Our study provides a new combination therapy approach for chemotherapy, with the hope of further improving the curative effect of anti-cancer therapy.

Using manual versus mechanized glide path instruments and ProTaper Gold versus ProTaper Next systems in curved canals: micro-CT study.

The aim of this study was to evaluate the root canal shaping effect of ProTaper Gold (PTG) versus ProTaper Next (PTN) instrumentation systems, and of a manual #15 K-type file (K15) versus the ProGlider (PG) mechanized instrument for glide path creation, in severely curved mesial canals. Twenty-four mandibular molars with two separate mesial canals were anatomically matched using computed tomographic scanning, and then divided into two groups (n=12) according to the glide path instrument used, either K15 or PG. In all teeth, the PTG system was used to prepare the mesiobuccal canal, and the PTN, the mesiolingual canal. The teeth were scanned by computed microtomography, before and after root canal preparation, and the values of the initial volume, final volume, volumetric variation, untouched walls, and canal transportation variables were determined. The data were analyzed using the two-way ANOVA test, and the Tukey test for multiple comparisons. There was no significant difference among the study groups regarding volumetric variation or root canal transportation, either in the cervical, middle or apical thirds, or in the entire root canal (p>0.05). In the apical third, the percentage of untouched walls was significantly higher in groups using K15 than in those using PG (p<0.05), namely 33.144% and 23.285%, respectively, irrespective of the instrumentation system. In the other regions, there was no difference between K15 and PG regarding this variable. It was concluded that PG was associated with a lower rate of untouched walls in the apical region than K15.

CERCETĂRI PRELIMINARE PRIVIND REALIZAREA UNUI MATERIAL COMPOZIT, BAZAT PE MATRICE DE NĂMOL ȘI DEȘEURI AGRICOLE, CA MATERIALE DE UMPLUTURĂ

The article presents the results of preliminary experiments necessary for the foundation of an experimental method that ensures the design and manufacturing technology for a category of composite materials with a mud matrix and agricultural waste insertion. The resources and physico-chemical properties of the mud matrix as well as the resources and physical properties of potential agricultural waste constituents of the insertion in the composite material are presented. The technological variant for the manufacture of the finished product is also presented, consisting of a compression system of the composite mixture in a paste state until solidification with moisture removal (dehydration). From a large number of parameters characterizing the experimental system, few have been varied (insertion concentration in the material, height of the raw material column in the press, raw material density, pressing force), while the quality parameters of the process have only been considered for the capacity of dehydration and material densification. The statistical analysis of the results shows that for the capacity of dehydration and densification, the main input parameters that influence are the initial moisture and initial volume of raw material. Results are obtained that allow the development of a mathematical model for the technological process of manufacturing the composite material. The purpose of the research described in this article is to determine the feasibility and feasibility conditions of the material in its possible variations. This means identifying the insertion concentration and moisture intervals of the material before extrusion, possible. The upper and lower limits of these parameters are sought, so that the material exiting the die does not immediately, or over time, disintegrate, and at the same time, the extrusion process is possible with a reasonable energy consumption.

A correlation study between prostate necrosis rate calculated by 3D Slicer software and clinical efficacy of prostatic artery embolization, along with an analysis of predictors of clinical success after prostatic artery embolization.

To analyze the correlation between the prostate necrosis rate at 1-month after prostatic artery embolization (PAE) and the clinical efficacy at 1-year after PAE, and to explore potential predictors of clinical success after PAE for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH). The prostate magnetic resonance imaging data at 1-month after PAE were imported into 3D Slicer software for calculating the prostate necrosis rate and thus analyzing the relationship between the prostate necrosis rate at 1-month after PAE and the efficacy score ratio at 1-year after PAE. The 151 patients with PAE technical success were divided into a clinical success group (n = 126) and a clinical failure group (n = 25). Independent predictors of clinical success after PAE were analyzed by multifactorial logistic regression, and the predictive performance of each factor was evaluated by applying the receiver operating characteristic curve and the area under the curve (AUC). There was a linear negative correlation between the prostate necrosis rate at 1-month after PAE and the efficacy score ratio at 1-year after surgery (P < 0.001). In the clinical success group, both the initial prostate volume (PV) and the prostate necrosis rate at 1-month after PAE were significantly higher than in the clinical failure group (P < 0.001), and acute urinary retention (AUR) and adenomatous-dominant BPH were also associated with clinical success (P < 0.05). Multifactorial logistic regression analysis revealed that larger initial PV, a higher prostate necrosis rate at 1-month after surgery, and AUR were independent predictors of clinical success after PAE. The AUC values for these three indicators and their combination were 0.720, 0.928, 0.599, and 0.951, respectively, in which the prostate necrosis rate at 1-month after PAE demonstrating a high predictive value. The higher the prostate necrosis rate at 1-month after PAE, the better the clinical efficacy at 1-year after PAE is likely to be, and the prostate necrosis rate at 1-month after PAE is expected to become a predictor of clinical success after PAE.

Effect of Retrograde Autologous Priming on Coagulation Assessed by Rotation Thromboelastometry in Patients Undergoing Valvular Cardiac Surgery

ObjectivesTo investigate the effect of retrograde autologous priming (RAP) on coagulation function using rotation thromboelastometry (ROTEM) in patients undergoing valvular heart surgery. DesignProspective, randomized, patient- and outcome assessor-blinded study. SettingSingle-center university hospital. ParticipantsPatients aged 20 years or more undergoing valvular heart surgery. Interventions104 patients were allocated to the RAP or control group (1:1 ratio). In the RAP group, the prime was displaced into the collection bag before bypass initiation. ROTEM was performed at the induction of anesthesia, at the beginning of rewarming, and after the reversal of heparinization. Allogeneic plasma products and platelet concentrates were transfused according to ROTEM-based algorithms. Measurements and Main ResultsAn average volume of 635 ± 114 mL was removed using RAP (from the 1,600 mL initial prime volume). The hematocrit 10 min after CPB was 24.7 ± 3.5% in the control group and 26.1 ± 4.1% in the RAP group (P=0.330). ROTEM including EXTEM, INTEM, and FIBTEM showed prolonged clotting time and decreased maximal clot firmness after CPB in both groups, without intergroup differences. The number of patients who received intraoperative erythrocyte (27% vs. 25%, control vs. RAP, P=0.823), fresh frozen plasma (14% vs. 8%, control vs. RAP, P=0.339), cryoprecipitate (21% vs. 12%, control vs. RAP, P=0.185), or platelet concentrate transfusion (19% vs. 12%, control vs. RAP, P=0.277) did not differ between the groups. ConclusionsCPB induced impaired coagulation function on ROTEM. However, RAP did not improve coagulation function when compared with conventional priming in patients undergoing valvular heart surgery.

Intraoperative Options to Stimulate the Reparative Liver Regeneration in the Experiment

Background. Primary and secondary malignant neoplasms and liver damage affect more than 500 million people worldwide; one million of these people die annually. Secondary malignant neoplasms of the liver occur in every fourth cancer patient, 60% of them require liver resection. As reported, post-resection liver failure occurs in 32–60% of cases. Thus, at the current stage of medicine development, the search for novel options to stimulate reparative liver regeneration remains a challenging issue in surgery.The aim of the study was to stimulate post-resection liver regeneration by intraoperative intrahepatic and intraperitoneal administration of cyanocobalamin and ademetionine in an experiment.Materials and methods. This research is a prospective randomized study carried out at the Research Institute of Experimental Biology and Medicine, N.N. Burdenko Voronezh State Medical University (VSMU), Ministry of Health of the Russian Federation. Experiments involved 192 mature male Wistar rats, who underwent conventional liver resection (CLR) equal approximately to 70% of the initial liver volume, according to the approach proposed by G. Higgins and R. Anderson. The effect of intraperitoneal administration of ademetionine and cyanocobalamin on post-resection liver regeneration was investigated in the first block of the study. The effect of intraoperative intrahepatic injections and intrahepatic administration of drugs on post-resection liver regeneration was tested in the second block of the study. The combined use of ademetionine and cyanocobalamin and their effect on post-resection liver regeneration was studied in the third block of the study. Physical examination and laboratory findings were used to assess reparative processes. The data were processed statistically using the STATGRAPHICS Centurion 18 software package, version 18.1.12 (Statgraphics Technologies, Inc., USA). The analysis of variance (ANOVA) was applied to compare mean values for eight different group.Results. The study detected that intraperitoneal administration of ademetionine helps to normalize the general condition and biochemical parameters in 77.78% of animals. Intraperitoneal administration of cyanocobalamin does not have a significant effect on biochemical parameters, including oxidative stress. Intrahepatic administration of cyanocobalamin helps to increase the reparative liver potential, results in decreased rates of cytolysis and cholestasis syndromes, restoration of carbohydrate and fat metabolism, and increased expression of growth factors. Intrahepatic administration of ademetionine leads to decreased regenerative liver potentials, disruption of its functional activity, and decreasd protective antioxidant properties.Conclusion. Thus, the optimal intraoperative option to stimulate reparative liver regeneration in the experiment is the intrahepatic administration of cyanocobalamin supplemented by intraperitoneal administration of ademetionine. In 7 days after liver resection, this helps normalize biochemical parameters, relieves oxidative stress, and increases IL-1β and TGF-β1. In 14 days after resection, the abovementioned events lead to restoration of 95.04% of the initial liver weight, if compared with intraperitoneal administration of cyanocobalamin and ademetionine (p0,05).

Counter-Ion Effect on the Surface Potential of Foam Films and Foams Stabilized by 0.5 mmol/L Sodium Dodecyl Sulfate

It is well known that the type of counter-ion affects the state of the adsorption layer of ionic surfactants and, consequently, its surface potential. Yet, it is not clear how they affect the foamability, the rate of foam decay or foam production. How is the surface potential of the air/water interface related to the properties of the foam? This work aims to answer these questions. Foam films, stabilized by 0.5 mmol/L sodium dodecyl sulfate (SDS) in the presence of added LiCl, NaCl, and KCl, were studied by means of the interferometric experimental setup of Scheludko–Exerowa. The surface potential values were derived from the equilibrium film thickness by means of the DLVO theory. A linear relation between the values of the surface potential and specific adsorption energy of the counter-ions on the air/water interface was established. The slope of this linear relation depends on the salt concentration. The foamability, the rate of foam decay, and the foam production of the same aqueous solutions of SDS and added salts were studied by means of the shaking method. A correlation was found between the derived surface potential of the foam film’s surfaces and the properties of the foam. The foam production, which is the ratio between the initial foam volume and the rate of foam decay, increases with the decrease in the surface potential. Previous studies in the literature confirm that the lower surface potential promotes higher surfactant adsorption, thus boosting more foam and vice versa. It was also confirmed that the dual effect of KCl on foam production involves converting the best foam stabilizer into a foam suppressor at the highest salt concentration.

Optimizing Si-Dominant Anodes in High-Energy Li-Ion Batteries with a Binary Binder System: Exploring Impacts on Adhesion, Cohesion, and Electrochemical Performance

Silicon anode stands out as a promising game-changer for Li-ion batteries (LIBs) due to its remarkable gravimetric and volumetric capacities, boasting 4200 mAh/g1 and 2200 mAh/cm3, respectively. In addition, its operating voltage of 0.4 V vs Li/Li+, abundant availability, and environmental friendliness make Si a strong candidate to revolutionize energy densities in the next-generation high-performance LIBs. However, challenges arise during lithiation as silicon undergoes an expansion of ~300% of its initial volume, leading to a cascade of detrimental effects on the electrode.1 The micron-sized silicon particles tend to pulverize, and resulting in fragmented silicon particles that become electrically isolated. Such volume variations compromise the adhesion of the Si electrode to the current collector. Furthermore, the repetitive expansion and shrinkage cycles contribute to cohesive failure within the electrode. Collectively, these factors considerably diminish the electrochemical performance and lifespan of Si anodes. Consequently, these challenges have placed major constraints on the utilization of silicon, making it currently viable only at levels below 10 wt% in LIB anodes, thereby impacting the commercial feasibility of Si-dominant anodes in high-energy LIBs.Such challenges in Si anodes impose strict demands on the binder, requiring it to maintain intimate contact between electrode components and to the current collector and preserve the integrity of ion and electron transport channels during frequent volume changes upon cycling. Obviously, the traditional binders like PVDF or carboxymethylcellulose (CMC)/Styrene-butadiene rubber (SBR) are not suitable options for addressing these specific challenges.Many approaches have been explored to address such requirements including increased crosslinking, different binding functionalities, adhesion promoters, etc.2 In this study, we investigate a binder system comprising two key components: (i) an acrylic acid-based polymer enriched with a high concentration of carboxyl groups. This component not only forms effective bonds with the silicon surface but also fosters interactions with other polar species, facilitating the self-healing properties. (ii) Incorporating a styrene-butadiene-based polymer, renowned for its exceptional flexibility, improves adhesion and enhances the tensile properties of the electrode, particularly in response to volume expansion challenges. We evaluated the characteristics of the binders and electrode properties, including adhesion to the current collector, cohesion within the electrode, and binder distribution. These properties were subsequently correlated with the initial columbic efficiencies (IEC) and electrode cycle life in Si-dominant/NMC811 cells. We show that there is an optimal binder ratio that achieves the desired adhesion and significantly enhances cohesive strength, leading to improved cycling stability compared to a single binder system.

Silicon Nanowires Diameter Modification for the Lithium-Ion Batteries

Silicon has been considered a prospective anode material for lithium-ion batteries (LIBs) due to its abundant reserves and high theoretical specific capacity (about 10 times higher than the graphite anode). However, the significant volumetric expansion of bulk silicon anode during cycling, which causes cracking and pulverization, results in irreversible capacity decay and a shorter lifetime compared to other anode materials.[1, 2, 3] The general strategy for performance and stability enhancement is the use of nanostructured silicon materials. Various nanostructured silicon electrodes had been developed, such as nanoparticles, nanorods, nanotubes, and hollow nanostructures.[4, 5] In this work, we demonstrate silicon nanowires (Si NWs) directly grown on current collecting substrates by a vapor-liquid-solid (VLS) approach that is capable of achieving a reversible capacity of over 2200 mAh g-1 with good cycling stability. The improved electrochemical performance, compared to previous studies, may be due to faster electron transport, higher surface reactivity and mechanical stability with the growth substrate. Additionally, in this study, we investigate a feasible approach for controlling Si NWs diameters to optimize electrochemical performance. Figure 1. Si nanowires growth scheme. (I) Bare stainless-steel mesh, which was (II) coated by different size tin (Sn) catalyst before the reaction, (III) the dense Si nanowires were anchored on the substrate.The vapor-liquid-solid (VLS) approach that we used is more economic and safer in producing pure Si NWs compared to the other methods, such as metal-assist etching, chemical vapor deposition, and oxide-assisted/magnesium thermal evaporation.[4] The difficulties for Si NWs synthesis are that it has a high melting point and good mechanical property as a semiconductor, which makes it harder to break it down from bulk Si material to nanowires.[4] On the other hand, various silicide might be formed instead of pure Si in the synthesis reaction, as the decomposition of Si precursor and nanowires nucleation happen at the same time, causing the undesirable specific capacity in the further application.[6] As shown in Figure 1, Si NWs were grown on the Sn-coated stainless-steel mesh after injecting the Si precursor. During the reaction, the specific size Sn catalyst is melted and formed as droplets on the substrate, the silane (vapor) is decomposed from phenyl silane and absorbed into the Sn droplet (liquid), Si NWs (solid) are then gradually extracted from the droplet when it got saturated.The electrochemical performance of the self-supported Si NWs/Stainless-steel mesh (SSM) electrodes show that Si NWs with the bigger diameter (SSM01 ~ 120 nm, SSM02 ~ 80 nm) delivered higher initial specific capacity (3761 mAh g-1 and 2871 mAh g-1 separately) but poor stability and decayed ~ 50% at the 100th cycle. The largely irreversible capacity loss may be due to bigger nanowires losing electronic contact after the initial volume change. The smaller wires (SSM03 ~ 41 nm, SSM05 ~ 45 nm) maintained ~ 80% capacity retention but achieved lower initial specific capacity (2201 mAh g-1 and 1872 mAh g-1 separately). This result illustrates that the stability can be improved by nano-sizing the electrode material, as the smaller diameter nanowires may result in faster ion transfer, while the unique electrode architecture leads to electrodes with higher surface reactivity, conductivity and improved robustness and electrode stability. This approach not only eliminated the use of excess explosive gas and the possibility of silicide impurity production but also avoids the energy-intensive top-down process.

Analytical analysis of cylindrical cavity expansion considering particle breakage effect of sand and its application for cone penetration tests

AbstractThe particle breakage effect in sand exerts a significant influence on the design of underground space structure. However, the existing theories seldom consider the breakage effect and often lack accurate descriptions of void ratio changes, leading to substantial errors in the numerical calculations compared to the actual scenario. This study employs the simple critical state sand model (SIMSAND) to account for the particle breakage effect and transforms the drained cylindrical cavity expansion problem into a set of first‐order ordinary differential equations described by the Lagrangian method. The analytical solution of the cylindrical cavity expansion problem is calculated using Matlab programming codes. Firstly, Fontainebleau sand is investigated to analyse the influence of initial stress, void ratio and specific volume around the cavity. The combined effects of initial stress and particle breakage on the soil around the cavities result in dilatancy characteristics and a reduction in void ratio. The stress path analysis reveals that the soil around the cavities only reaches a critical state under high initial stresses. Secondly, a plane strain numerical model is established for twice expansion to verify the calculation outcomes from the cylindrical cavity expansion theory. Finally, an axisymmetric cone penetration test (CPT) model is developed to analyse the theoretical and numerical solutions for expansion stress and sleeve friction. The research results indicate that the CPT in sand need to consider the particle breakage effect, especially under high stress conditions. Without considering particle breakage, the sleeve friction is overestimated. These research findings can offer guidance for geotechnical engineering applications, such as CPT, pressuremeter tests and predictions of bearing capacity for pile foundations in sand.

Application of the electrical resistivity method and the estimation of limestone volume: a case study

The present work used the electrical resistivity approach to conduct a three-dimensional modeling and initial volume estimation of the limestone layer in the Mintom region located in southern Cameroon. In order to achieve the objectives of the study, a total of 21 electrical soundings spaced 250 m were first collected in the field using the Schlumberger array. These soundings were conducted along three profiles oriented in an east–west direction, spaced 500 m. Additionally, a geological survey was conducted to identify and emphasize the presence of limestone formations within the designated study region. The interpretation of the sounding data was conducted based on the analysis of the sounding curves. The interpretation outcomes, specifically resistivity and thickness, were compared with the geological field data, resulting in the development of lithostratigraphic logs for each sounding. The geological sections were constructed using the logs of the designated profile. The lithological logs were utilized to establish a lithological interface model and calculate the volume of the limestone layer at 260 ± 13 × 106 m3, utilizing the inverse distance method built into RockWorks software. A resistivity value is assigned to each geological layer in a sounding curve, allowing for the development of a resistivity variation model specific to the limestone layer. The proposed model facilitates the categorization of limestone layers based on their resistivity variations, thus serving as a fundamental reference for prospective exploratory activities within the designated study region. Our integrated approach provides a replicable model for a better understanding of the limestone reserve and effective management of this valuable resource.

Prognostic Value of Tumor Volume, Tumor Volume Reduction Rate and Magnetic Resonance Tumor Regression Grade in Rectal Cancer.

Background and Objectives: Rectal cancer poses significant treatment challenges, especially in advanced stages. Radiologic assessment, particularly with MRI, is critical for surgeons and oncologists to understand tumor dynamics and tailor treatment strategies to improve patient outcomes. The purpose of this study was to correlate MRI-based tumor volumetric and tumor regression grade analysis in patients with advanced rectal cancer, assessing the impact of preoperative chemotherapy (CT) alone or chemoradiotherapy (CRT) on surgical technique choices. Materials and Methods: Between 2015 and 2022, a prospective study was enrolled, including a cohort of 89 patients diagnosed with rectal cancer at stage II or III. The participants were divided into two distinct therapy groups, ensuring an equal distribution with a ratio of 1:1. The initial group was treated with the contemporary preoperative chemotherapy protocol FOLFOX4. In contrast, the alternative group received conventional preoperative chemoradiotherapy. Before surgery, each patient underwent a rectal MRI scan at 1.5 T, including T2-weighted and diffusion-weighted imaging (DWI) sequences. Results: The CT group showed a 36.52% tumor volume reduction rate (TVRR), and the CRT group showed 54.87%, with varying magnetic resonance and pathological tumor regression grades (mrTRG and pTRG). Analysis revealed a significant interaction between mrTRG and tumor volumetrics (volume and VRR) in both groups, especially CRT, underscoring the complexity of tumor response. Both treatment groups had similar initial tumor volumes, with CRT displaying a higher TVRR, particularly in higher pathological TRG (3/4) cases. This interaction and the strong correlation between mrTRG and pTRG suggest mrTRG's role as a non-invasive predictor for treatment response, highlighting the need for personalized treatment plans. Conclusions: Rectal tumor volume, volume reduction rate, and mrTRG are not just abstract measures; they are concrete indicators that have a direct and practical impact on surgical decision-making, planning, and prognosis, ultimately influencing the quality of care and life expectancy of patients with rectal cancer.

Connecting Structural Characteristics and Material Properties in Phase-Separating Polymer Solutions: Phase-Field Modeling and Physics-Informed Neural Networks.

The formed morphology during phase separation is crucial for determining the properties of the resulting product, e.g., a functional membrane. However, an accurate morphology prediction is challenging due to the inherent complexity of molecular interactions. In this study, the phase separation of a two-dimensional model polymer solution is investigated. The spinodal decomposition during the formation of polymer-rich domains is described by the Cahn-Hilliard equation incorporating the Flory-Huggins free energy description between the polymer and solvent. We circumvent the heavy burden of precise morphology prediction through two aspects. First, we systematically analyze the degree of impact of the parameters (initial polymer volume fraction, polymer mobility, degree of polymerization, surface tension parameter, and Flory-Huggins interaction parameter) in a phase-separating system on morphological evolution characterized by geometrical fingerprints to determine the most influential factor. The sensitivity analysis provides an estimate for the error tolerance of each parameter in determining the transition time, the spinodal decomposition length, and the domain growth rate. Secondly, we devise a set of physics-informed neural networks (PINN) comprising two coupled feedforward neural networks to represent the phase-field equations and inversely discover the value of the embedded parameter for a given morphological evolution. Among the five parameters considered, the polymer-solvent affinity is key in determining the phase transition time and the growth law of the polymer-rich domains. We demonstrate that the unknown parameter can be accurately determined by renormalizing the PINN-predicted parameter by the change of characteristic domain size in time. Our results suggest that certain degrees of error are tolerable and do not significantly affect the morphology properties during the domain growth. Moreover, reliable inverse prediction of the unknown parameter can be pursued by merely two separate snapshots during morphological evolution. The latter largely reduces the computational load in the standard data-driven predictive methods, and the approach may prove beneficial to the inverse design for specific needs.

Prevalence and Predictors of Hemorrhagic Foci on Long-term Follow-up MRI of Recent Single Subcortical Infarcts

AbstractHemorrhagic foci surrounding the lacune in the long-term evolution of recent single subcortical infarcts (RSSIs) remains largely unexplored. We aimed to determine the prevalence, characteristics, and predictors of hemorrhagic foci in patients with RSSI. From a prospective, longitudinal study of RSSIs, we recruited patients who underwent multimodal MRI assessments both at baseline and approximately one year after the stroke onset. Hemorrhagic foci were identified using susceptibility-weighted imaging (SWI). Among 101 patients with RSSI, nearly half (n = 45, 44.6%) had hemorrhagic foci within the index RSSI lesions on follow-up SWI. RSSIs with hemorrhagic foci formation were associated with a longer time to follow-up imaging (median 449 versus 401 days, P = 0.005) and higher likelihood of being located in the anterior circulation compared to those without hemorrhagic foci (88.9% versus 64.3%, P = 0.003). Hemorrhagic foci were also associated with larger lesion size (P &lt; 0.001), a higher proportion of cavitation formation (P = 0.003), higher baseline NIHSS scores (P = 0.004), and poorer functional outcomes (P = 0.001). In the subset of RSSIs in the lenticulostriate artery (LSA) territory, after adjustment for covariates, larger initial lesion volume (OR 1.80, 95% CI 1.13–2.87; P = 0.014) and greater decreases in LSA total length (OR 0.59, 95% CI 0.36–0.96; P = 0.035) were independently associated with hemorrhagic foci formation. The extent of ischemia in the initial infarct is predictive of the presence of hemorrhagic residues. Our findings contribute to the current understanding of the mechanisms underlying the evolution of RSSIs.

ATTENTION-GUIDED COST VOLUME REFINEMENT NETWORK FOR SATELLITE STEREO IMAGE MATCHING

Abstract. In remote sensing, disparity calculation using stereo images is a very necessary task and provides information for estimating the terrain elevation. The fields using disparity of stereo satellite images are used in various fields such as terrain models, autonomous driving using 3D maps, and content development. However, extracting disparity from stereo satellite images is a very difficult task, and inaccurate disparity may be extracted due to complex environments, façade areas of buildings, and texture-less areas. Our proposed method improves feature extraction and 3D aggregation steps based on Gwc-Net using stereo images rectified through RPC (Rational Polynomial Coefficients). To this achieve, we first improve the accuracy of the initial cost volume by extracting important features using the attention module 2D CBAM. In addition, in the aggregation step, we use 3D CBAM to extract important features from the cost volume and use GCE (Correlate-and-Excite) to guide image features to the cost volume to improve disparity. To evaluate the proposed method, the accuracy of disparity is evaluated using RPC-corrected stereo satellite images of DFC2019 data track2 of the US3D dataset. As a result of the experiment, the proposed method exhibited improvement compared to the baseline Gwc-Net.

Numerical Simulation of Gas Explosion with Non-uniform Concentration Distribution by Using OpenFOAM.

Gas explosions in coal mines have occurred occasionally, which may cause casualties and economic losses. In the actual mine roadway, the gas concentration distribution is uneven because the gas density is lower than that of air. Gas explosion characteristics of uneven gas distribution with the concentration gradient in mine roadways were analyzed by using the open-source computational fluid dynamic code OpenFOAM. The flame and pressure characteristics were calculated, and the flame and shock wave propagation laws of the non-uniform gas-air mixture explosion with different concentration gradients were analyzed and compared with the uniform gas-air mixture gas. The results show that when the overall gas concentration is the same, the flame velocity and the pressure growth rate of the uniform gas explosion are lower than those of the non-uniform, but the pressure peaks of both are similar. At the same time, when the initial volume concentration is 10%, the non-uniform gas explosion has the highest flame propagation velocity and peak value. The peak explosion pressure of different concentration gradients is proportional to the initial concentration. The above studies clarified the characteristics of gas-air mixture explosions with concentration gradients and provided theoretical support for the prevention and control of gas explosion disasters.

10053-MNG-1 STRATIFICATION OF TUMOR VOLUME GROWTH RATE USING RISK FACTORS IN SUPRATENTORIAL MENINGIOMAS

Abstract BACKGROUND The natural history of meningiomas is still unclear, and no guidelines have been established based on objective indices regarding the necessity and timing of therapeutic intervention. Objective: We attempted to provide statistics on the characteristics of tumor volume change, stratify tumor growth by risk factors, and generate a predictive tumor volume curve based on the statistics, with the aim of describing the natural history of meningiomas. METHODS 313 cases were included in the study, with the origin of meningioma being the circumflex and parasagittal sinus areas and the cerebral sickle region, and with multiple MRI scans performed at intervals of at least 3 months. Relative growth rate (RGR) and annual volume change (AVC) were calculated by tumor volume, and the patients were classified into three groups according to the combination of gender, age, and MRI T2WI signal intensity, and compared. RESULTS The median RGR and AVC of the entire cohort were 6.1% and 0.20 cm3/year, respectively, and there were significant differences between groups in gender (p=0.018) and MRI T2WI (p &amp;lt; 0.001) for RGR and tumor location (p=0.025) and initial tumor volume (p &amp;lt; 0.001)for AVC. The median RGR and AVC in the classification were 17.5% and 1.05 cm3/year for the very high growth group, 8.2% and 0.33 cm3/year for the high growth group, and 3.4% and 0.04 cm3/year for the low growth group, showing significant differences between the groups (p &amp;lt; 0.001). The predicted tumor volume curve showed an average 2.24-fold or 5.24 cm3 increase in volume over 5 years in the very high-growth group, while little tumor volume change was observed in the low-growth group. CONCLUSION The combination of growth risk factors allowed stratification of tumor growth and provided a predictive tumor volume curve for each county. The results may assist in the treatment of supratentorial meningiomas.