Microscopic Visualization Research Articles

Activated charcoal application in gastric ulceration areas in horses: preliminary experimental study

Gastric ulceration is frequent in adult horses, bringing significant economic and welfare implications to these animals. Treatment may employ several drugs, but adsorbents, such as activated charcoal, are not mentioned. Activated charcoal may be a valuable therapeutic option mainly because of its few adverse effects, fecal elimination, and low cost. This study aimed to evaluate the use of activated charcoal in experimentally induced gastric ulceration in horses and perform the microscopic characterization of charcoal particles in the injured epithelium. Five adult, undefined breed horses underwent a gastric ulcer induction protocol based on alternating fasting and free food access periods. Next, we performed a gastroscopic examination and applied activated charcoal diluted in water at the ulcers through a probe passed through the working channel of the gastroscope. The gastric mucosa was washed with water after a contact period of 5 min until the complete lack of macroscopic product visualization. Then, we performed a biopsy of the aglandular mucosa in erosive to ulcerative injury sites and a microscopic assessment of the fragments. Macroscopically, all animals presented ulcerative lesions in the greater or lesser gastric curvature along the margo plicatus and hyperkeratosis in the aglandular portion. Microscopically, all animals had hyperplasia, hyperkeratosis, epithelial erosion, desquamated epithelial cells, inflammatory cells, and variable amounts of charcoal particles, either free or adhered to the epithelium. We concluded that activated charcoal remains adhered to aglandular gastric lesions in horses even after lavage with water and histological processing, allowing its microscopic visualization. Therefore, activated charcoal’s effectiveness as a therapy for equine gastric lesions warrants evaluation.

Consolidation Enhancement of Weathered Coal Gangue Utilized for Aggregate Filling of Cement Pavement in Mining Area

The large-scale, open-air storage of coal gangue often leads to oxidation and decomposition due to natural weathering, resulting in decreased strength and instability, which limits its wider application in concrete pavement. To address these issues, this paper proposed a composite consolidation treatment for weathered coal gangue (WCG), assessing its effectiveness and enhancement mechanisms through aggregate performance tests, mixture performance tests, and microscopic visualization analyses. Results indicated that the initial and post-20 dry–wet cycle crushing values of WCG were 23.96% and 47.94%, respectively, failing to meet required standards. However, applying a composite consolidation treatment using a lithium curing agent and cement paste significantly improved WCG’s robustness and stability. After 4 days of treatment, the crushing value, impact value, and Vickers hardness of WCG had reached 18.3%, 6.58%, and 113.52 kgf/mm², respectively, fully meeting the standards for aggregate filling in mini concrete pavements. Furthermore, tests demonstrated that the lithium curing agent induced the formation of hydrated calcium silicate and calcium aluminate on both the surface and interior of the WCG, enhancing its structural stability. Approximately 5–12 wt.% of the curing agent penetrates and encapsulates the WCG, strongly bonding and reinforcing its internal weak surfaces. These findings offer potential solutions and technical insights for the large-scale management of weathered coal gangue.

Research on the Blocking Mechanism of Stagnant Water and the Prediction of Scaling Trend in Fractured Reservoirs in Keshen Gas Field

In this paper, well Keshen 221 was taken as the research object. The stagnant water–rock static experiment showed that, after 8 weeks of the residual water–rock static reaction, the pore size of the inner profile of the rock slice increased from 5 μm to 90 μm, and calcium carbonate crystals were deposited in the hole. Combined with the microscopic visualization model, it is observed that the reservoir blockage mostly occurs at the pore throat diameter, and the small fracture (30 μm) is blocked first, then the large fracture (50 μm). So, it is inferred that the blockage of the reservoir flow channel is caused by the migration of the crystals precipitated by the interaction between the stagnant water and the reservoir rock. On this basis, the TOUGHREACT reservoir model was further constructed to simulate the scaling of the stagnant water in the reservoir matrix and used to compare the scaling of the fractures with 7% and 30% porosity and the retained water at 0.658 m and 768 m. The pre-results of reservoir scaling show that the scaling is more serious when the fractures occur in the far well zone than when the fractures occur in the well entry zone. At the same location, the deposition of large fractures is six times that of small fractures, and the scaling is more severe in large fractures.

Screening for Sexually Transmitted Infections in Adolescents with Genitourinary Complaints: Is There a Still Role for Endocervical Gram Stains?

Study objective: Adolescent females are disproportionately affected by Sexually Transmitted Infections (STIs). Endocervical Gram stain smears taken during gynecological examination are inexpensive, relatively easy procedures to perform and interpret. The purpose of this study was to evaluate the performance characteristics of Gram smears in the diagnosis of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (GC) and Trichomonas vaginalis (TV) in a female adolescent population presenting to the Emergency Department (ED) with genitourinary complaints. Methods: This study was a retrospective, cohort analysis of consecutive females (ages 13 – 19) seen at three academic medical centers over a two-year study period. All patients underwent a pelvic exam with diagnostic testing for STIs. Positive criteria for a Gram stain included greater than ten white blood cells per high-power field, gram-negative intracellular/extracellular diplococci (suggesting GC), or direct visualization of TV organisms. Polymerase Chain Reaction (PCR) assays were used as the gold standard definition for CT/GC infection. Direct microscopic visualization of organisms on a separate wet mount prep was considered the gold standard for TV infection. Demographic information, clinical findings of cervicitis, and the results of diagnostic testing were obtained from ED records using standardized abstraction forms. Results: During the study period, 1303 adolescent females were evaluated for genitourinary complaints. A total of 181 adolescents (12.9%) had at least one documented STI. Overall, 298 patients (22.9%) had positive gram stains. The sensitivity, specificity, and positive likelihood ratio for Gram stain in the diagnosis of STI were 28.7% (95% CI, 22.2 to 35.9), 78.1% (95% CI, 75.5 to 80.5), and 1.31 (95% CI 1.0 to 1.7), respectively. The sensitivity of Gram stain to Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis were 35.9% (95% CI 26.8 to 45.8), 34.5% (95% CI 18.0 to 54.3), and 5.7% (95% CI 1.3 to 15.7), respectively. The consistency of the data recording was excellent, with a median kappa statistic of 0.89. Conclusions: The positive likelihood ratio of inflammation on endocervical Gram stain is too low to recommend its use to direct empiric treatment of adolescents at risk for sexually transmitted infections. Diagnostic uncertainty or treatment failures should prompt specific laboratory testing.

Streamlined chemical fixation method for morphological investigation of Candida albicans with scanning electron microscopy

This method describes the preparation of Candida albicans specimen for scanning electron microscopy (SEM), starting from specimen collection to obtaining SEM images. Our approach involves preserving cellular structure and preventing cell degradation through chemical fixation and post-fixation without Osmium tetroxide (OsO4), followed by air dried specimen placed onto Si substrate. Additionally, the method outlines the steps for mounting the prepared specimen onto SEM sample holder aluminum stubs, followed by coating with an ultrathin gold layer via thermal evaporation to enhance specimen/substrate/stub conductivity. The specimens are then mounted in the SEM sample holder. This step-by-step procedure demonstrates successful morphological analysis of C. albicans, providing a comprehensive and effective specimen preparation for SEM analysis.•Effective preparation of Candida albicans specimens for SEM analysis, preserving cellular structure.•Step-by-step specimen mounting and gold coating for enhanced detailed SEM imaging.•Chemical fixation of yeast cells for electron microscopy visualization.

Micro-scale flow simulation study of low-yield wells in tight gas reservoirs

Abstract The mechanism of gas-water flow in reservoirs has traditionally been characterized macroscopically based on flow experiments, but the microscopic mechanisms of gas-water flow in porous media cannot be precisely described experimentally. This paper categorizes low-yield gas wells into Types I, II, and III. With microscopic visualization principles, three different types of core thin-section photos were selected to construct a pore structure model, allowing for micro-scale flow simulation to examine micro-scale percolation patterns in various types of low-yield gas well reservoirs. The results show that there is a shorter displacement time in Type I reservoirs compared to Type II and III reservoirs which exhibit more pronounced fingering phenomena.

Abstract C054: Current anticancer drugs differentially impact Black and White prostate cancer cell lines

Abstract Introduction/Background: In pre-clinical models of prostate cancer (PCa) such as the utilization of cell lines, it is important to address the limited diversity present. This acknowledgment is vital to facilitate equitable assessment of the efficacy and safety of drug development across various races and ethnicities. Of all commercially available PCa cell lines, 98% of them are of European origin. The genetic and biological disparities between PCa cell lines derived from men of European ancestry (MEA) and men of African ancestry (MAA) may underlie the observed enhanced responsiveness of tumours to existing anticancer agents in MEA compared to MAA. This difference is notable given that MAA are 2.5 times more likely to succumb to PCa. This study compared the cytotoxic effects of five anticancer drugs (Docetaxel, Cabazitaxel, Abiraterone, Olaparib, Enzalutamide) and the natural product betaine on MAA (ACRJ-PC28, MDA-PCA-2b) and MEA (DU-145, PC-3) PCa cell lines. Method: After a 72-hour treatment with the anti-cancer drugs and the natural product, the inhibitory effects of these anti-cancer agents on the four cell lines were investigated using three different assays. CellTiter Aqueous, Neutral Red, and Crystal Violet assays were utilized due to distinct growth patterns observed in the various cell lines. By comparing the optical density (OD) readings and examining the cellular morphology through microscopic visualization, we aimed to determine which assay(s) yielded the most reliable results in determining accurate IC50 values. Results: Drug selectivity was observed for Abiraterone and Olaparib that were most effective in ACRJ-PC28 (IC50 = 1.10 μM) and PC-3 (IC50 = 0.28 μM) cells compared to the other PCa cell lines. Enzalutamide differentially impacted MAA, (IC50= 206 μM for ACRJ-PC28 and 104 μM for MDA-PCA-2b) and MEA (IC50 = 37 μM for PC-3 and 48 μM for DU-145) PCa cell lines. However, no distinct impact was observed for Docetaxel (IC50s = 0.05 nM for ACRJ-PC28; 0.08 nM for MDA-PCA-2b, 0.07 nM for PC-3 and 0.08 nM for DU-145) and Cabazitaxel ((IC50s = 0.56 nM for ACRJ-PC28; 0.45 nM for MDA-PCA-2b, 0.43 nM for PC-3 and 0.38 nM for DU-145) as both drugs impacted the cell lines very potently in the nM range. Conclusion: Due to the heterogenous nature of cancers, especially in PCa, a single drug or drug class may not be the best course of treatment. Instead, a combination of drugs with different mechanisms may be more suitable for addressing the diversity in cancer types. This points to the evolving understanding of personalized cancer treatment, where a strategic integration of first, second, and third-line therapies can effectively address the genetic and epigenetic factors that are unique to individuals in cancer management. Citation Format: Simone Badal, Bor-Jang Hwang, Ashlianne Nelson, Kristoff Frank, Rory Thompson, Belinda Morison, Valerie Marah, Camille Ragin. Current anticancer drugs differentially impact Black and White prostate cancer cell lines [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C054.

Mechanical Performance of a Hot Mix Asphalt Modified with Biochar Obtained from Oil Palm Mesocarp Fiber

A recently used material that shows environmental and technical advantages for use as an asphalt binder modifier is biochar (BC). Different biomasses can be converted into BC by pyrolysis. One agro-industrial biomass that is abundant in copious quantities is oil palm mesocarp fiber (OPMF) obtained from African palm cultivation. In the present study, the use of a BC obtained from OPMF (BC-OPMF) as a modifier of asphalt binder (AC type) to produce a hot mix asphalt (HMA) was evaluated. This type of BC has not been investigated or reported in the reference literature as a binder and/or asphalt mix modifier. Initially, AC was modified with BC in three ratios (BC/AC = 5, 10, and 15%, with respect to mass) to perform penetration, softening point, and rotational viscosity tests; rheological characterization at high and intermediate temperatures; and scanning electron microscope (SEM) visualization. Based on this experimental phase, BC/AC = 10% was chosen to manufacture the modified HMA. Resistance parameters under monotonic loading (stability—S, flow—F, S/F ratio of the Marshall test, and indirect tensile strength in dry—ITSD and wet—ITSC conditions) and cyclic loading (resilient modulus, permanent deformation, and fatigue resistance under stress-controlled conditions) were evaluated on the control HMA (AC unmodified) and the modified HMA. Additionally, the tensile strength ratio (TSR) was calculated to evaluate the resistance to moisture damage. Abrasion and raveling resistance were evaluated by performing Cantabro tests. BC-OPMF is shown to be a sustainable and promising material for modifying asphalt binders for those seeking to increase stiffness and rutting resistance in high-temperature climates, resistance to moisture damage, raveling, and fatigue without increasing the optimum asphalt binder content (OAC), changing the volumetric composition of the HMA or increasing the manufacturing and construction temperatures.

Comparative electron microscopic visualization of the lung alveolar epithelial glycocalyx with different staining and labeling methods.

The alveolar surface of the lung is lined by an epithelium consisting of type I (AECI) and type II alveolar epithelial cells (AECII). This epithelium is covered by a liquid alveolar lining layer (ALL). Besides intra-alveolar surfactant, ALL also contains the alveolar epithelial glycocalyx on the apical side of AECI and AECII. To better understand the alveolar epithelial glycocalyx, its ultrastructural visualization by transmission electron microscopy is required. The aim of this study was to systematically re-evaluate routine cytochemical methods for visualization of the alveolar epithelial glycocalyx and specifically its glycan components. For this purpose, we used chemical fixation by vascular perfusion with aldehydes as a common routine approach in mice. After fixation, staining is needed for glycocalyx visualization. Cytochemical staining agents such as alcian blue, ruthenium red, and lanthanum nitrate were compared. In addition, SNL (Sambucus nigra lectin) and UEA1 (Ulex europaeus agglutinin I) were used for sialic acid and fucose-specific labeling. Alcian blue showed the strongest staining, with cloud-like structures, whereas ruthenium red appeared as thread-like structures. On the other hand, lanthanum nitrate did not stain the alveolar epithelial glycocalyx. For specific sialic acid and fucose labeling, both lectins presented a specific signal. In conclusion, these methods can be used routinely for assessing ultrastructural changes of the alveolar epithelial glycocalyx in experimental invivo models under different physiological and pathological conditions. In addition, cytochemical staining by tissue massage and post-embedding lectin labeling after vascular perfusion support 3R (reduction, refinement, replacement) principles of animal welfare.

Bioplastic production by harnessing cyanobacteria-rich microbiomes for long-term synthesis

Departing from the conventional axenic and heterotrophic cultures, our research ventures into unexplored territory by investigating the potential of photosynthetic microbiomes for polyhydroxybutyrate (PHB) synthesis, a biodegradable polyester that presents a sustainable alternative to conventional plastics. Our investigation focused on a cyanobacteria-enriched microbiome, dominated by Synechocystis sp. and Synechococcus sp., cultivated in a 3 L photobioreactor under non-sterile conditions, achieving significant PHB production—up to 28 % dry cell weight (dcw) over a span of 108 days through alternating cycles of biomass growth and PHB accumulation. Nile Blue staining and Transmission Electron Microscope visualization allowed to successfully confirm the presence of PHB granules within cyanobacteria cells. Furthermore, the overexpression of PHA synthase during the accumulation phase directly correlated with the increased PHB production. Also, gene expression changes revealed glycogen as the primary storage compound, but under prolonged macronutrient stress, there was a shift of the carbon flux towards favoring PHB synthesis. Finally, analysis through Raman, Fourier- transform infrared spectroscopy and proton Nuclear Magnetic Resonance further validated the extracted polymer as PHB. Overall, it was demonstrated for the first time the feasibility of using phototrophic microbiomes to continuous production of PHB in a non-sterile system. This study also offers valuable insights into the metabolic pathways involved.

A CO2-responsive Janus SiO2 nanofluid: Integration of enhanced oil recovery and demulsification

Aiming to address the issues of limited suitability of conventional chemical oil displacement materials for formation conditions and the serious emulsification of oil and water in the produced liquid, the innovative nano oil-displacing system with CO2-responsive behavior has been developed. This system integrates oil displacement and emulsion breaking. The efficacy of the CO2-response system in creating stable emulsions with a high capacity to decrease interfacial tension has been demonstrated. The interfacial responsive behavior of all active components, including Janus nanoparticles, sodium oleate, gums, and asphaltenes, in the emulsion system was analyzed in terms of interfacial rheology and adsorption. Additionally, the prepared system demonstrated a rapid response to CO2, effectively breaking the emulsion within 5 min. Furthermore, the oil recovery enhancing mechanism of the CO2-response system was investigated using a microscopic visualization model. The system was proved to be efficient in initiating the residual oil within pore channels. Considering the combined effectiveness of the CO2-response system in terms of efficient oil displacement and rapid response, it offers valuable insights for advancing the chemical flooding technology of in enhanced oil recovery.

High-Speed Three-Dimensional Scanning Force Microscopy Visualization of Subnanoscale Hydration Structures on Dissolving Calcite Step Edges.

Hydration at solid-liquid interfaces plays an essential role in a wide range of phenomena in biology and in materials and Earth sciences. However, the atomic-scale dynamics of hydration have remained elusive because of difficulties associated with their direct visualization. In this work, a high-speed three-dimensional (3D) scanning force microscopy technique that produces 3D images of solid-liquid interfaces with subnanoscale resolution at a rate of 1.6 s per 3D image was developed. Using this technique, direct 3D images of moving step edges were acquired during calcite dissolution in water, and hydration structures on transition regions were visualized. A Ca(OH)2 monolayer was found to form along the step edge as an intermediate state during dissolution. This imaging process also showed that hydration layers extended from the upper terraces to the transition regions to stabilize adsorbed Ca(OH)2. This technique provides information that cannot be obtained via conventional 1D/2D measurement methods.

Droplet size, spray structure and droplet velocity mapping in hollow cone sprays using SLIPI-based techniques

The Structured Laser Illumination Planar Imaging (SLIPI) technique received significant attention in recent years due to notable improvements in the measurement of droplet size and the visualization of internal structure in both dilute and dense sprays. However, despite the improvements, the technique remains limited to these microscopic characteristics of the spray, primarily due to the complexity of the optical setup and image acquisition process. In this article, the capabilities of the SLIPI application are exploited, specifically employing the 3p-SLIPI-LIF/Mie (SLSD), and combined application of 1p-SLIPI-LIF & PIV (1p-SLIPI-PIV) for mapping of both Sauter Mean Diameter (SMD) and mean droplet velocity in combination with detailed spray structure analysis. The measurements were carried out in hollow cone sprays operated at the range of injection pressures from 25 to 107 bar. The results obtained using the SLIPI techniques were compared with the Phase Doppler Anemometry (PDA) measurements showing good agreement for both the SMD and mean droplet velocity. The significant improvements in the important microscopic characteristics (droplet size & velocity) and visualization of the internal structure in a wider flow field of hollow cone sprays allowed detailed analysis and understanding of the dispersed phase flow owing to the suppression of diffused light resulting from the multiple scattering effects.

Scanning Tunneling Microscopy Visualization of Polaron Charge Trapping by Hydroxyls on TiO2(110).

Using scanning tunneling microscopy (STM), we investigate the spatial distribution of the bridging hydroxyl (OHb) bound excess electrons on the rutile TiO2(110) surface and its temperature dependence. By performing simultaneously recorded empty and filled state imaging on single OHbs at different temperatures in STM, we determine that the spatial distribution of the OHb bound excess electrons retains a symmetric four-lobe structure around the OHb at both 78 and 7 K. This indicates that OHbs are much weaker charge traps compared to bridging O vacancies (Ob-vac). In addition, by sequentially removing the capping H of each OHb using voltage pulses, we find that the annihilation of each OHb is accompanied by the disappearance of some lobes in the filled state STM, thus verifying the direct correlation between OHbs and their excess electrons.

How I do it. Posterolateral lumbar spine fixation and decompression with navigation interfaced with a robotic exoscope with head mounted display.

Lumbar spine fixation and fusion is currently performed with intraoperative tools such as intraoperative CT scan integrated to navigation system to provide accurate and safe positioning of the screws. The use of microscopic visualization systems enhances visualization and accuracy during decompression of the spinal canal as well. We introduce a novel setting in microsurgical decompression and fusion of lumbar spine using an exoscope with robotized arm (RoboticScope) interfaced with navigation and head mounted displays. Spinal canal decompression and fusion can effectively be performed with RoboticScope, with significant advantages especially regarding ergonomics.

Utilization of mycelial polysaccharide from Schizophyllum commune for the formation of highly stable o/w emulsion

This study investigated the emulsifying properties of a hot water extracted polysaccharide (SCMP) derived from liquid fermentation mycelium of Schizophyllum commune in stabilizing oil-in-water (o/w) emulsions. SCMP demonstrated the ability to stabilize o/w emulsions (referred to as SCMPe) for extended periods (>21 days) even at low concentrations (2 g/L) and increased the viscosity and elasticity of the emulsion system. Through confocal laser-scanning microscope visualization, it was observed that SCMP created a physical barrier on the surface of the oil droplets, contributing to emulsion stability. Furthermore, SCMPe demonstrated excellent tolerance to varying concentrations of Na+ (0.1–0.5 mol/L) and Ca2+ (0.01–0.05 mol/L) as well as a wide pH range (3.0–9.0). Moreover, increasing SCMP concentration effectively inhibited lipid oxidation and improved the stability of β-carotene and curcumin in the emulsion during storage. A detailed analysis of SCMP's composition and structure was done to better understand its emulsifier properties, revealing SCMP to be composed of two β-glucans with a rigid chain and high molecular weight. These results suggest that SCMP holds great potential an efficient stabilizer in the food industry, particularly in enhancing emulsion stability.

Bioactive compound from marine seagrass Streptomyces argenteolus TMA13: combatting fish pathogens with time-kill kinetics and live-dead cell imaging.

Actinobacteria, pervasive in aquatic and terrestrial environments, exhibit a filamentous morphology, possess DNA with a specific G + C content and production of numerous secondary metabolites. This study, focused on actinobacteria isolated from marine seagrass, investigating their antibacterial activity against fish pathogens. Among 28 isolates, Streptomyces argenteolus TMA13 displayed the maximum zone of inhibition against fish pathogens-Aeromonas hydrophila (10mm), Aeromonas caviae (22mm), Edwardsiella tarda (17mm), Vibrio harveyi (22mm) and Vibrio anguillarum (12mm) using the agar plug method. Optimization of this potent strain involved with various factors, including pH, temperature, carbon source and salt condition to enhance both yield production and antibacterial efficacy. In anti-biofilm assay shows the maximum percentage of inhibition while increasing concentration of TMA13 extract. Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) assays with TMA13 crude extract demonstrated potent activity against fish pathogens at remarkably low concentrations. Time-kill kinetics assay showcased growth curve variations over different time intervals for all fish pathogens treated with a 100µg/ml concentration of crude extract, indicating a decline in cells viability and progression into the death phase. Additionally, fluorescence microscopic visualization of bacterial cells exposed to the extracts emitting green and red fluorescence, enabling live-dead cell differentiation was also studied. Further characterization of the crude extract through GC-MS and FT-IR analyses performed and identified secondary metabolites with functional groups exhibiting significant antibacterial activity. This study elucidates the capacity of Streptomyces argenteolus TMA13 to enhance the production of antibiotic compounds effective against fish pathogens.

Atomic resolution transmission electron microscopy visualisation of channel occupancy in beryl in different crystallographic directions

The causes of colour in beryl have been a research topic for decades. For some varieties, such as emerald (green, coloured by Cr3+ and/or V3+), the main cause of colour is substitutions by metal atoms within the framework. However, the causes for the yellow and blue colours in heliodor, golden beryl and aquamarine are still debated. It is generally agreed that Fe ions are responsible for the colour, but there are differing conclusions about the valence states of these ions, the occupied positions and the colour-inducing processes involved. The colour of aquamarine is commonly attributed to intervalence charge transfer (IVCT) between Fe3+ and Fe2+. Various combinations of sites have been proposed to host the Fe ions engaging in this IVCT. Here we present a new approach to address the topic of colour generation: atomic resolution scanning transmission electron microscopy (STEM). For the first time, atomic resolution images of a beryl (natural aquamarine) are presented in the three crystallographic directions [0001], [1-210] and [1-100]. Ions are clearly resolved in the channels. From the ratio of channel occupation and the correlation of the atoms per formula unit (apfu) calculations we conclude that Fe resides in the framework, not in the channels. The projections in the [1-210] direction directly show that the cavity channel site 2a is occupied, most likely by Cs, in agreement with recent results in the literature.

Analysis of damage mechanisms and controlling factors of fine particle migration in unconsolidated sandstone reservoirs based on reservoir classification

AbstractParticle migration in oil and gas reservoirs is a common phenomenon in the process of oil and gas development, and is considered to be an important reason for the damage of reservoir permeability and the reduction of oil and gas productivity. The mechanism of this phenomenon includes the desorption, migration, and precipitation of particles, which eventually clogs the throat and causes reservoir damage. Therefore, it is necessary to accurately characterize the complex mechanism of particle migration and identify the main controlling factors of particle migration, which is very important for efficient oilfield development and plugging solution. First, the reservoir types are divided into three types and the pore structure models of different types of reservoirs are established. Then, computational fluid dynamics and discrete element coupling method numerical simulation and microscopic visualization of pore throat structure model were combined, to characterize the rules of particles and migration, and analyze the main controlling factors. Finally, a typical model of particle migration and clogging is established. The results show that particle size/throat and particle concentration are the key factors affecting particle plugging, and particle migration has the least effect on the permeability of Type I reservoir and the greatest damage to Type III reservoir. According to the mechanical and hydrodynamic behavior of particles in porous media, three mechanisms and six modes of particle plugging are proposed.

Infection of Phytophthora palmivora Isolates on Arabidopsis thaliana.

Phytophthora palmivora, a hemibiotrophic oomycete, causes diseases in several economically important tropical crops, such as oil palm, which it is responsible for a devastating disease called bud rot (BR). Despite recent progress in understanding host resistance and virulence mechanisms, many aspects remain unknown in P. palmivora isolates from oil palm. Model pathosystems are useful for understanding the molecular interactions between pathogens and hosts. In this study, we utilized detached leaves and whole seedlings of Arabidopsis thaliana Col-0 to describe and evaluate the infection process of three P. palmivora isolates (CPPhZC-05, CPPhZC-04, CPPhZOC-01) that cause BR in oil palm. Two compatible isolates (CPPhZC-05 and CPPhZOC-01) induced aqueous lesions at 72 h post-inoculation (hpi), with microscopic visualization revealing zoospore encysting and appressorium penetration at 3 hpi, followed by sporangia generation at 72 hpi. In contrast, an incompatible isolate (CPPhZC-04) exhibited cysts that could not penetrate tissue, resulting in low leaf colonization. Gene expression of ten P. palmivora infection-related genes was quantified by RT-qPCR, revealing overexpression in compatible isolates, but not in the incompatible isolate. Additionally, key genes associated with salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in Arabidopsis exhibited regulation during interaction with the three isolates. These findings demonstrate that P. palmivora can infect Arabidopsis Col-0, and variability is observed in the interaction between Arabidopsis-Col-0 and P. palmivora isolates. Establishing this pathosystem is expected to enhance our understanding of P. palmivora's pathology and physiology.