Permeability Values Research Articles

TMOD-27. RECURRENT GLIOBLASTOMA AFTER LASER ABLATION OF THE PRIMARY TUMOR IN A PRECLINICAL ORTHOTOPIC MODEL EXHIBIT INCREASED GENETIC SIGNATURES OF CELL CYCLE AND CELL MOTILITY

Abstract Image-guided laser interstitial thermal therapy (LITT) is a minimally invasive tumor cytoreductive treatment for recurrent gliomas and tumors in eloquent loci. We have adapted this technique to develop an image-guided glioblastoma (GBM) ablation model, its recurrence and have tested the efficacy of imaging biomarkers in evaluating tumor ablation and recurrence. The cytopathology and molecular signatures of the primary and recurrent tumors were compared. Immune-compromised female rats were implanted with U251N tumor cells in one brain hemisphere (n=20). Tumor growth was monitored using magnetic resonance imaging (MRI). When tumors reached about 4 mm in diameter, they were ablated using a clinical LITT system (Visualase®), under MRI guidance. Five other rats implanted with U251N tumors were used as unablated controls. MRI data were acquired at 24 h post-LITT, and at 2 and 4 weeks. Rats were sacrificed for histopathology at 2 and 4 weeks, and brain sections stained for hematoxylin and eosin, human major histocompatibility complex, Ki67, a cell proliferation marker and sex determining region Y)-box 2 (SOX2), a stem cell transcription factor. An additional cohort of rats with primary (n=4) and post-LITT recurrent (n=4) U251N tumors were used for analysis of their molecular composition using RNA-Seq approach. In the treated groups, MRI showed little tumor tissue at 24 h, evidence of recurrence at 2 weeks and significant tumor tissue at 4 weeks. Tumor DCE-MRI parameters showed elevated intra-tumoral vascular permeability (i.e., Ktrans) values at pre-LITT imaging, that shifted to peri-ablation periphery at 24 h. A trend of progressive decrease in Ktrans was seen until 1-week post-ablation. Increasing Ktrans values at 2 weeks and after 4 weeks coincided with tumor recurrence. RNA-Seq data showed that cell cycle, cellular movement and inflammatory disease genes were the most differentially expressed genes in the recurrent tumors suggesting increased infiltration may primarily underlie treatment resistance.

Antibacterial and wound healing stimulant nanofibrous dressing consisting of soluplus and soy protein isolate loaded with mupirocin

Severe cutaneous injuries may not heal spontaneously and may necessitate the use of supplementary therapeutic methods. Electrospun nanofibers possess high porosity and specific surface area, which provide the necessary microenvironment for wound healing. Here in, the nanofibers of Soluplus-soy protein isolate (Sol-SPI) containing mupirocin (Mp) were fabricated via electrospinning for wound treatment. The fabricated nanofibers exhibited water absorption capacities of about 300.83 ± 29.72% and water vapor permeability values of about 821.8 ± 49.12 g/m2 day. The Sol/SPI/Mp nanofibers showed an in vitro degradability of 33.73 ± 3.55% after 5 days. The ultimate tensile strength, elastic modulus, and elongation of the Sol/SPI/Mp nanofibers were measured as 3.61 ± 0.29 MPa, 39.15 ± 5.08 MPa, and 59.11 ± 1.94%, respectively. Additionally, 85.90 ± 6.02% of Mp loaded in the nanofibers was released in 5 days in vitro, and by applying the Mp-loaded nanofibers, 93.06 ± 5.40% and 90.40 ± 5.66% of S. aureus and E. coli bacteria were killed, respectively. Human keratinocyte cells (HaCat) demonstrated notable biocompatibility with the prepared nanofibers. Furthermore, compare to other groups, Sol-SPI-Mp nanofibers caused the fastest re-epithelialization and wound healing in a rat model. The findings of this study present a novel nanofiber-based wound dressing that accelerates the healing of severe skin wounds with the risk of infection.

Development and Optimization of Transferosomal Gel for Efficient Topical Delivery of Berberine Hydrochloride

Background: Berberine is an isoquinoline alkaloid with potent anti-inflammatory effects. However, its therapeutic efficacy is often restricted by its poor solubility, absorption, and permeability, especially in topical applications. Transferosomes are elastic vesicular carriers with high skin permeability values and retention, making them suitable for encapsulating hydrophilic and lipophilic actives. Objective: The objective of this research was to develop a transferosome-based topical gel formulation of Berberine hydrochloride (BER) to improve its skin permeability and anti-inflammatory efficacy. Method: The thin film hydration method was used to formulate the BER transferosomes. The effects of independent variables, amount of BER in lipid phase (X1), and lipid (Phospholipon 90G) to surfactant ratio (X2) on BER entrapment and vesicle size were studied using face-centered central composite design. The characterization was performed using differential scanning calorimetry, transmission electron microscopy, and X-ray diffraction. The optimized batch (F5) was incorporated in Carbopol gel and further investigated for viscosity, in vitro and ex-vivo diffusion, skin retention by tape stripping, and in-vivo anti-inflammatory efficiency. Results: The formulation optimized with 50 mg of drug and a 5:1 lipid-to-surfactant ratio (F5) demonstrated higher drug entrapment efficiency (72.11%) and lower vesicle size (77.9 nm). TEM validated the spherical vesicle morphology, whereas DSC and XRD analysis confirmed the molecular entrapment of BER within the phospholipid vesicles. The transferosomal gel demonstrated improved BER diffusion (0.63 mg/cm2) confirmed by in vitro and ex-vivo diffusion experiments that revealed a 6-fold increase in flux and permeability coefficient (0.1053 mg. cm-2.h-1). The drug release from transferosome gel was non-Fickian in nature (n = 0.6575), indicating an integration of diffusion and erosion processes. Furthermore, BER transferosomal gel displayed substantial anti- inflammatory activity in rats (p < 0.001). result: The independent variables exerted a substantial impact on drug entrapment and transferosome vesicle size. The optimized batch (F5) exhibited 72.11 % of BER entrapment and 77.9 nm vesicle size. DSC studies indicated molecular dispersion of BER in phospholipon G. The change in BER crystalline state was indicated by the XRD study. In vitro, diffusion study of Transferosome gel formulation indicated the sustained release by a non-fickian mechanism. Ex vivo skin permeation revealed significant improvement in BER permeation (p< 0.05). Further, the tape-stripping method revealed higher BER skin permeability. In-vivo anti-inflammatory efficacy of BER transferosome gel was significantly higher as compared to plain BER gel. Conclusion: The findings demonstrated the potential of transferosomal gel as a promising approach for efficient drug delivery and therapeutic efficacy.

Liquid and gas permeabilities of nanostructured layers: Three-dimensional lattice Boltzmann simulation

Liquid water and gas permeabilities in nanostructured catalyst layers (CLs) (pore size ∼10–150 nm) and microporous layers (MPLs) (pore size ∼50 nm-5 μm) are crucial to reduce the mass transport loss in proton exchange membrane fuel cells (PEMFCs). Experimental measurement of their permeabilities poses great challenges due to their brittle and thin characteristics. Presently, considerable discrepancy exists in the reported permeability values for CLs and MPLs in the literature with variation spanning several orders of magnitude. This study digitally reconstructed various nanostructures of similar pore size as CLs and MPLs to calculate their permeabilities using the Lattice Boltzmann Method (LBM) based on no-slip (e.g. for liquid water flow in MPL and CL's secondary pores) or slip condition (e.g. for gas flow in MPL). Analysis was performed to evaluate the range of pore size in nanostructures for the two boundary conditions. A comprehensive investigation was conducted under various parameters such as the Reynolds number (Re), sphere diameter, porosity, and pore structure. The results revealed that permeability exhibits an increasing trend with the diameter and porosity. The predicted permeability of randomly arranged spheres agrees well with established correlations. The random sphere structure demonstrates higher permeability than their body-centered cubic (BCC) and face-centered cubic (FCC) counterparts. Under slip boundary condition, the permeability was enhanced, compared to the no-slip condition. This study's novelty lies in using distinct boundary conditions to assess the permeabilities of liquid and air, based on flow pattern analysis in the CL and MPL pore structures. A new empirical correlation describing the influence of the Knudsen number (Kn) on the slip permeability was developed, exhibiting consistency with simulation across the entire porosity spectrum.

Cu-doped nanocomposite Pr2Fe14B/α-Fe ribbons with high (BH)max

Abstract The melt-spun ribbons of nominal composition Pr9Fe84.2-xB6.2P0.3Zr0.3Cux (x=0, 0.5, 1, 2) were prepared at wheel speeds of 21, 27, 30, and 33 ms-1. The XRD patterns show that as the wheel speed increases, the crystallinity of the 2:14:1 hard phase decreases, while that of the α-Fe soft phase increases. The (BH)max, remanence, and coercivity are improved from 63 kJm-3, 0.85 T, and 515 kAm-1 for the Cu-free ribbons to 171 kJm-3, 1.08 T, and 684 kAm-1 with x=0.5. The high squareness ratio of Jr/Js ~ 0.82 at 0.5 at. % Cu (27 ms-1) indicates strong exchange coupling due to small grain sizes of 15 and 30 nm for soft and hard magnetic phases, respectively. The SEM images revealed smooth morphology and uniform element distribution at 0.5 at. % Cu (27 ms-1), contributing to the high magnetic properties. The low recoil permeability (μ rec ) value of 5.466×10-4 to 1.970×10-4 $\frac{T}{k A m^{-1}}$ confirms the strong exchange coupling with x=0.5 (27 ms-1). The initial magnetization curves show that the coercivity mechanism of the Cu-free alloy evolves from the nucleation of the reverse domain to the domain wall pinning as the wheel speed increases, resulting in a high coercivity value of 818 kAm-1 (33 ms-1). Conversely, for the Cuadded alloy, the coercivity mechanism changes from pinning to the nucleation of the reverse domain from low to high wheel speed.

Revealing membrane integrity and cell size from diffusion kurtosis time dependence.

The nonmonotonic dependence of diffusion kurtosis on diffusion time has been observed in biological tissues, yet its relation to membrane integrity and cellular geometry remains to be clarified. Here we establish and explain the characteristic asymmetric shape of the kurtosis peak. We also derive the relation between the peak time , when kurtosis reaches its maximum, and tissue parameters. The peak shape and its position qualitatively follow from the adiabatic extension of the Kärger model onto the case of intra-cellular diffusivity time-dependence. This intuition is corroborated by the effective medium theory-based calculation, as well as by Monte Carlo simulations of diffusion and exchange in randomly and densely packed spheres for various values of permeability, cell fractions and sizes, and intrinsic diffusivity. We establish that is proportional to the geometric mean of two characteristic time scales: extra-cellular correlation time (determined by cell size) and intra-cellular residence time (determined by membrane permeability). When exchange is barrier-limited, the peak shape approaches a universal scaling form determined by the ratio . Numerical simulations and theory provide an interpretation of a specific feature of kurtosis time-dependence, offering a potential biomarker for in vivo evaluation of pathology by disentangling the functional (permeability) and structural (cell size) integrity in tissues. This is relevant as the time-dependent diffusion cumulants are sensitive to pathological changes in membrane integrity and cellular structure in diseases, such as ischemic stroke, tumors, and Alzheimer's disease.

Optimization of Barrier Properties of PLA/PBAT Polymers in Biodegradable Materials

AbstractDespite its popularity as a bio‐based biodegradable material, polylactic acid (PLA) has a number of shortcomings. Nevertheless, the combination of poly(butylene adipate co‐terephthalate) (PBAT) and thermoplastic starch (TPS) to enhance the mechanical properties of PLA was achieved through the utilisation of PLA/PBAT/TPS ternary composites, which were created through the calendering method. These composites exhibit advantageous characteristics, including high ductility, enhanced toughness, and biodegradability. The results of the water vapour permeability test indicate that the proportion of the material composition exhibiting the lowest value of water vapour permeability is 2.0571 g/m²·24h. The results of the water vapour transmission test demonstrate that the material generated by the composition ratio has the lowest water vapour transmission, indicating that the composite material blending effect is superior. The majority of current research employs nanocellulose as a substrate in PLA, with a paucity of studies investigating its use in PLA/PBAT/TPS composites. These composites are modified due to the notable divergence of nanocellulose from the hydrophobicity of the composite and its susceptibility to decomposition at elevated temperatures. This study establishes a foundation for future research in this field.

A low-cost device for measuring TEER at cultivation of epithelial/endothelial cells on inserts.

Background: The barrier properties of epithelial and endothelial cells are usually studied in vitro when cells are cultured on mesh inserts in culture plates, and it is necessary to assess the state of the cell monolayer on the membrane of the inserts before the experiment. Typically, monolayer density is analyzed by passing a fluorescent label through the insert with cells or by measuring the transendothelial resistance (TEER) of the cell layer. Many studies use both methods of assessing monolayer integrity in parallel, depending on the purpose of the study. The TEER method also allows to record early changes in the monolayer state under the action of various substances. Aim of this work is to demonstrate the possibility of TEER measurements using the proposed device (conductometer) made from freely available components using endothelial/epithelial cells as an example. Materials and Methods. A device (conductometer) for measuring TEER, created on the basis of easily accessible components, is presented. The device was tested by culturing two cell lines – hybridoma of endothelial origin Ea.hy926 and human colon adenocarcinoma Caco-2. Caco-2 cells were cultured for 22 days and Ea.hy926 cells were cultured for 7 days. The integrity of the cell monolayer and the density of intercellular contacts were evaluated by the TEER value determined by the proposed conductometer, as well as by the fluorescein permeability of the cell monolayer. Results: The results of TEER measurements using the proposed device and at the same time, the fluorescein permeability of the cell monolayer during the cultivation of Caco-2 and EA.hy926 cells are presented. For Caco-2 cells from the moment of 100% confluence the TEER value gradually increased reaching maximum values by 20-21 days, after which it decreased slightly. The permeability values decreased as the cells were cultured, indicating the formation of dense contacts. For EA.hy926 cells the rise in TEER values are observed on day 3 and decrease was observed on day 7. The results of TEER and permeability obtained by the proposed conductometer have a strong inverse correlation for both cell lines and are in good agreement with each other. Conclusions. The presented device, made on the basis of simple and affordable components, is similar to commercially available devices and can be used to study the integrity and density of a monolayer in the cultivation of epithelial/endothelial cells, to study the processes of trans/paracellular transport under the action of various substances, as well as in experiments with the co-cultivation of various cell lines.

Development and Characterization of a Human Mammary Epithelial Cell Culture Model for the Blood-Milk Barrier-A Contribution from the ConcePTION Project.

It is currently impossible to perform an evidence-based risk assessment for medication use during breastfeeding. The ConcePTION project aims to provide information about the use of medicines during lactation. The study aimed to develop and characterize an in vitro model of the blood-milk barrier to determine the extent of the milk transfer of xenobiotics, relying on either on human mammary epithelial cells (hMECs) or immortalized cell lines derived from breast tissue. The hMECs were cultured and characterized for epithelial markers; further, the ability to form an epithelial barrier was investigated. Drug transporter functionality in the cultured hMECs was analyzed with specific probe substrates. The hMECs showed an epithelial morphology and the expression of epithelial markers and tight junctions. They formed a reproducible tight barrier with a transepithelial electrical resistance greater than 400 Ωcm2, unlike immortalized cell lines. Different levels of mRNA expression were detected for 81 genes of membrane transporters. Functional assays showed no evidence for the transporter-mediated secretion of medicines across the hMECs. Nevertheless, the hMEC-based in vitro model covered a 50-fold range of permeability values, differentiating between passive transcellular and paracellular-mediated transport. The cultured hMECs proved to be a promising in vitro model for biorelevance; the wide characterization of hMECs makes them useful for studying medicine partitioning in milk.

Modelling of Steady-State Seepage of an Embankment Dam Using Teaching-Learning Based Optimization Algorithm

The goal of the this study is to investigate the applicability of the teaching-learning based optimization (TLBO) algorithm for modeling seepage in embankment dams. The input parameters selected for the models to be built are the values of permeability (ks), van Genuchten's suitability parameters α and n, whose effect on seepage has been investigated over the years due to their uncertainties. The validity of the TLBO was compared with that of conventional regression analysis (CRA) methods. Both methods were utilized with different regression forms. The parameters chosen as input are modeled as random variables with a log-normal distribution, and total discharge (Q) was obtained. Four statistical indices, that is, root mean square error, mean absolute error, average relative error and coefficient of determination, were used to evaluate the performance of the models. The equations obtained using TLBO algorithms can predict the total discharge in embankment dams better than CRA. In addition, the reliability of TLBO has been demonstrated by conducting analyses using the outputs of CRA as a benchmark.

Perfusion computer tomography of the kidneys. Research technique. Perfusion indicators in the norm: case-control

INTRODUCTION: Perfusion computed tomography (PCT) is a contrast research technique that allows one to assess blood flow in the cortical and medulla layers of the renal parenchyma at the level of the microcirculatory bed, the influence of additional renal vessels and stenoses of the renal arteries on hemodynamics in the renal parenchyma.OBJECTIVE: To optimize the technique of perfusion computed tomography of the kidneys. Determine the most informative indicators of perfusion in the renal parenchyma in the norm. Assess the relationship between perfusion parameters and the number of renal vessels, the presence of renal artery stenosis.MATERIALS AND METHODS: PCT was performed in 46 patients with no anamnestic and clinical laboratory data on kidney disease who were undergoing examination for other pathological conditions, including 35 patients aged from 20 to 90 years (average age — 63.1 years) without hemodynamically significant stenosis and 11 patients aged from 64 to 94 years (mean age 80.3 years) with renal artery stenosis of 50% or higher. Perfusion indices were calculated using maximum slope and deconvolution algorithms, kinetic curves were plotted on a time-density graph, and color parametric maps.RESULTS: A quantitative assessment of perfusion parameters in the cortical and medulla of the kidneys, a qualitative analysis of the state of its parenchyma on color parametric maps, and the shapes of kinetic curves on the time-density graph were analyzed. Changes in perfusion parameters were established depending on the age, number and condition of the renal vessels.DISCUSSION: In the renal cortical layer, there was a predominance of indicators of blood flow velocity (BF), blood flow volume (BV), the rate of increase in the density of the contrast agent (CM) in the tissue (MSI), capillary wall permeability (PS) and lower values of the average transit time of the contrast agent (MTT) and the time to reach the maximum contrast agent density in the tissue (TTP) in comparison with the medulla. On the color parametric maps BF, BV, MSI, the cortical layer was characterized by intense red coloring, the medulla — yellow-green, on the TTP map green and blue coloring of the layers was determined, respectively. In elderly patients, there was a decrease in BF, BV with a concomitant lengthening of TTP in the cortical layer without changes in coloring on color parametric maps. On the density-time graph, the kinetic curve of the cortical layer was characterized by the appearance of a peak 10 seconds after the onset of the peak value in the abdominal aorta with further continuation of the curve in the form of a plateau; the kinetic curve of the medulla was characterized by a gradual moderate rise in the curve from 15 seconds after the start of scanning without the formation of peaks values.CONCLUSION: PCT is an informative method for quantitative and qualitative assessment of perfusion in the renal parenchyma.

Transforming Agro-Industrial Waste into Bioplastic Coating Films.

Addressing the environmental impact of agro-industrial waste, this study explores the transformation of banana, potato, and orange peels into bioplastics suitable for thin coating films. We prepared six extracts at 100 g/L, encompassing individual (banana peel, BP; orange peel, OP; and potato peel, PP) and combined [BP/OP, BP/PP, and BP/OP/PP] formulations, with yeast mold (YM) medium serving as the control. Utilizing the spin-coating method, we applied 1 mL of each sample at 1000 rpm for 1 min to create the films. Notably, the OP extract demonstrated a twofold increase in bioplastic yield (860.33 mg/L) compared to the yields of BP (391.43 mg/L), PP (357.67 mg/L), BP/OP (469.40 mg/L), BP/PP (382.50 mg/L), BP/OP/PP (272.67 mg/L), and YM (416.33 mg/L) extracts. Atomic force microscopy analysis of the film surfaces revealed a roughness under 8 nm, with the OP extract recording the highest at 7.0275 nm, whereas the BP/OP mixture exhibited the lowest roughness at 0.2067 nm and also formed the thinnest film at 6.5 nm. With R2 trend values exceeding 0.9950, the films exhibited water vapor permeability values ranging from 3.05 × 10-3 to 4.44 × 10-3, with the OP film being the least permeable and the BP/PP films the most permeable. The OP film demonstrated the lowest solubility in both water and ethanol with values of 64.71 and 1.05%, respectively. The solubilities of all films were above 60% in water and below 4% in ethanol. Furthermore, the films exhibited antimicrobial efficacy against both Gram-positive and Gram-negative bacteria. Our findings confirm the potential of utilizing banana, orange, and potato peels as viable substrates for eco-friendly bioplastics in thin-film applications.

Evaluation of CO2/Water Imbibition Relative Permeability Curves in Sandstone Core Flooding—A CFD Study

Greenhouse gases such as CO2 can be safely captured and stored in geologic formations, which in turn can reduce the carbon imprint in the Earth’s atmosphere and therefore help toward reducing global warming. The relative permeability characteristics in CO2/brine or CO2/water systems provide insight into the CO2 trapping efficacy of formations such as sandstone rocks. In this research, CO2/water imbibition relative permeability characteristics in a typical sandstone core sample are numerically evaluated. This work uses transient computational fluid dynamics (CFD) simulations to study relative permeability characteristics, and a sensitivity analysis is performed based on two different injection pressures and absolute permeability values of the sandstone rock material. Results show that when the irreducible water fraction remains unchanged, the imbibition relative permeability to the non-wetting phase decreases with an increase in injection pressure within the sandstone core sample. Also, with the irreducible water fraction being unchanged, relative permeabilities to both non-wetting and wetting phases decrease with an increase in the absolute permeability of the rock material. Finally, at irreducible water saturation, relative permeability to the gas phase decreases with an increase in injection pressure.

Impact of dicarboxystilbene impurities on the properties of swift heavy ion latent tracks in PET films

We present a new hypothesis and supporting experimental evidence about the essential role played by small impurities of dicarboxystilbene in the process of UV treatment of PET films irradiated with swift heavy ions (SHI). This treatment both forms highly selective membranes with permeability values comparable to natural ones (the track-UV technique) and sharply accelerates the etching of latent tracks in membrane production (the track-etching technique). We hypothesize (1) that these high permeability value is due to the presence of a molecular motor of an Archimedes screw type in the central part of the latent track formed by photoinduced trans-cis isomerization of dicarboxystilbene molecules that are anchored in helical conformations in the latent track; and (2) that the acceleration of etching rates is due to the preferential accumulation of phenanthrene-type molecules in the central part of the latent track due to the existence of a cyclization channel for photoexcited molecules of cis-dicarboxystilbene. In the presence of alkali solution, phenanthrene molecules release electrons which behave as strong anions in aqueous solution, catalyzing alkaline hydrolysis of PET molecules in the central part of the track. We present experimental observations of photoinduced changes in transmission light intensity after track-UV light treatment of both pristine and SHI irradiated PET films that confirm the presence of trans-cis isomerization of dicarboxystilbene molecules and show their contribution to the formation of new helical conformations in SHI irradiated PET films during the light treatment.

Separating Neroli from Water Using the PDMS‐ZSM5 Mixed Matrix Membrane and the Pervaporation Method

AbstractIn this study, the separation of neroli from water by PDMS‐ZSM5 mixed matrix membrane and separation performance of the pervaporative process of the prepared membranes with the parameters of permeability flux and separation factor was investigated. The effect of adding nanoparticles in the polymer matrix, the effect of the operating parameter of temperature and concentration on the efficiency of the membrane in the pervaporative process to be placed. Comparison of the results for pure membrane and mixed matrix membrane shows a 3‐fold increase in flux along with a 5‐fold increase in the separation factor in the mixed matrix membrane with a ratio of 12% nano in the membrane matrix so that the permeability and separation factor are 1.256 kg/m2h and 550, respectively. Membrane function was also evaluated in the temperature range of 298–353 K and feed concentration of 122–209 ppm. With increasing temperature to 353 K, permeability of membrane containing 8% ZSM‐5 nanoparticles increased from 0.63 to 0.89 kg/m2h. Also, with increasing feed concentration, permeability increased from to 0.96 kg/m2h. The optimization of these conditions was investigated by response surface method (RSM) based on the design of central points (CCD). The effect of all three parameters on the permeability, flux, and separation factor was investigated simultaneously and the optimal conditions were obtained at 12 wt% of ZSM‐5, a concentration of 209 mg/L of neroli, and a temperature of 304 K. Under these optimal conditions, the values of permeability, flux, and separation factor were 1.414 kg/m2h and 1039.57, respectively.

A comparison study of pore structure and permeability of sandstone by BSE-SE images

The pore structure and permeability of geotechnical materials are critical parameters that guide underground engineering. With advancements in digital imaging technology, scanning electron microscopy (SEM) has emerged as a vital tool for examining the pore structure and permeability of these materials. SEM operates in two primary modes: backscattered electron imaging (BSE) and secondary electron imaging (SE), each of which emphasizes different aspects of the material’s structure. However, few studies have been conducted to elucidate the influence of these two modes on the quantification of geotechnical structural characteristics. This study undertakes a more comprehensive quantitative analysis of the structure and permeability of sandstones by juxtaposing the two modes. The findings indicate that the BSE mode excels in analyzing the structure and composition, whereas the SE mode highlights the surface morphology. In terms of image segmentation, BSE mode images are more conducive to effective segmentation. Although SE images permit viable segmentation when preprocessed, they tend to represent a greater number of discrete tiny pores. Furthermore, there exists a discernible correlation between pore size and shape, wherein larger pores exhibit heightened roughness and deviate more from sphericity. Notably, these larger pores predominantly contribute to the material's permeability. Given that the BSE mode more readily captures continuous pore structures, the permeability values derived from BSE images are significantly higher than those obtained from SE images. These findings hold profound implications for enhancing our comprehension of geotechnical materials' pore structure and permeability, thereby informing the strategic use of BSE and SE modes in related studies.

A Novel Theoretical Method for Upscaling Permeability in Hydrate‐Bearing Sediments

AbstractThe accurate prediction of Darcy‐scale permeability (absolute permeability and gas‐water relative permeability) of hydrate‐bearing sediments (HBS) plays a crucial role in assessing reservoir potential and optimizing recovery strategies. However, the challenges of field coring, the rigorous conditions encountered in laboratory permeability tests, and the multi‐scale pore structure characteristics of HBS complicate the understanding of the relationship between pore structures and Darcy‐scale permeability of HBS. In this study, we propose an innovative upscaling method that integrates flow properties of typical regions, such as coarse, medium, and fine regions, to predict the Darcy‐scale permeability of HBS from the pore‐scale. This method considers two hydrate habits (pore‐filling and grain‐coating hydrates), heterogeneity and anisotropy of HBS, and multi‐scale pore structures. Taking the absolute permeability of hydrate‐free sediments in the y direction for example, the permeability values for the fine region, the medium region, the coarse region, and the equivalent HBS are 9.43 D, 13.59 D, 18.87 D, and 14.06 D, respectively. Thus, the predicted permeability (14.06 D) is much closer to the experimental data (15.44 D), which validates the efficacy of our upscaling method in estimating Darcy‐scale permeability. Moreover, the characteristics of our predicted Darcy‐scale permeability align with those reported in previous literature. This approach introduces a groundbreaking perspective for predicting permeability in HBS from pore‐scale to Darcy‐scale. It offers essential insights into predicting permeability in HBS while effectively preserving the impact of pore‐scale structural variations caused by local heterogeneity and facilitating numerical simulations of gas production from hydrate reservoirs.

Sodium alginate edible films incorporating cactus pear extract: antimicrobial, chemical, and mechanical properties

The potential benefits of biodegradable and functional food packaging materials have garnered increasing attention in recent years. Sodium alginate (SA), a commonly utilized polysaccharide, is particularly noteworthy for producing biodegradable films for food packaging. This study aimed to investigate SA-based edible films enriched with various proportions of cactus pear peel extract (CPPE). We assessed the films and extracts for total phenolic content, antimicrobial and antioxidant activities, as well as mechanical properties. Cactus pear peels powder (CPPP) exhibited higher contents of total polyphenols (1243.82 mg GAE/100 g), total flavonoids (18.92 mg QE/100 g), and betalains (2.28 mg/100 g). The main constituents detected were catechol, pyrogallol, catechin, and alpha-coumaric acid, with concentrations of 1013.82, 223.45, 148.21, and 101.02 ppm, respectively, contributing about 45.71%, 9.85%, 6.54%, and 4.46% of the total phenolic compounds. The thickness of the SA films increased from 0.220 mm to 0.265 mm. The tensile strength values ranged from 1.98 to 3.12, while the elongation at break values for SA-CPPE films decreased relative to the plain SA film. Moreover, the inclusion of CPPE improved the barrier characteristics (with water vapor permeability values for SA films with 1%, 2%, and 3% CPPE ranging from 0.72 × 10−5 g·h−1·m−1·Pa−1 to 1.68 × 10−5 g·h−1·m−1·Pa−1) and induced variations in flexibility and resistance. The plain SA film did not exhibit any inhibitory activity against bacteria and fungi. However, the inclusion of CPPE in alginate films showed favorable antibacterial properties, which improved progressively with increasing CPPE concentration. These findings highlight the potential of incorporating active alginate-based films in food preservation.

Permeability and Dynamic Stability in Porous Asphalt Mixtures Using Cariphalte Asphalt and Gilsonite Additives

Porous asphalt mixture is a new generation of flexible pavement that allows water to seep into the top layer (wearing course) both vertically and horizontally. This condition is possible, because the gradation used has a coarse aggregate fraction of not less than 85% of the mixture volume. This layer uses an open gradation (open graded) which is spread over a layer of waterproof asphalt to prevent seepage into the road foundation. This porous asphalt layer can effectively provide a greater level of safety, especially during rainy times to prevent aqua-planing, resulting in rougher surface roughness and can reduce noise (noise reduction). In this research, a test will be carried out on porous asphalt with a mixture using Cariphalte modified asphalt and gilsonite as the added ingredient. Variations in asphalt content used are 4%, 5%, 6%, 7%, 8%. Determination of variations in levels of variation is based on research that has been conducted. This research involves analysis of calculation results based on experimental data from laboratory scale experiments including Marshall Testing, Immersion Index, Permeability, Slip Resistance, Dynamic Stability, and Resilient Modulus. The test results show that the smallest permeability value is in the 8% gilsonite mixture but it does not meet the requirements of AAPA 2004 so the mixture with the greatest stability value is used. From the results of dynamic stability testing, it shows that the mixture of test objects with a content of 7% gilsonite has a dynamic stability value of 5250 passes/mm at a temperature of 45°C and 3150 passes/mm at a temperature of 60°C.

Studies of Phase Transformation Kinetics in the System of Nanocrystalline Iron/Ammonia/Hydrogen at the Temperature of 350 °C by Means of Magnetic Permeability In Situ Measurement

The kinetics of phase transformations in the nitriding process α-Fe → γ’-Fe4N → ε-Fe3-2N of the pre-reduced iron ammonia synthesis catalyst was investigated under in situ conditions (atmospheric pressure, 350 °C) by measuring changes of mass, gas phase composition, and magnetic permeability in a differential tubular reactor. The iron nanocrystallite size distribution according to their specific active surface areas was measured, and it was found that the catalyst is bimodal as the sum of two Gaussian distributions, also differing in the value of the relative magnetic permeability. Relative magnetic permeability of small α-Fe crystals in relation to large crystals is higher by 0.02. In the area of α → γ’ transformation, the magnetic permeability dependencies change, proving the existence of two mechanisms of the α-Fe structure change in the α-Fe → γ’-Fe4N transformation. In the first area, a solution of α-Fe (N) is formed with a continuous and insignificant change of the crystal lattice parameters of the iron lattice. In the second area, there is a step, oscillatory change in the parameters of the iron crystal lattice in FexN (x = 0.15, 0.20, 0.25 mol/mol). In the range of γ’-Fe4N → ε-Fe3-2N transformation, a solution is formed, with nitrogen concentration varying from 0.25–0.45 mol/mol. During the final stage of the nitriding process, at a constant value of the relative magnetic permeability, only the concentration of nitrogen in the solution εr increases. The rate of the phenomenon studied is limited by a diffusion rate through the top layer of atoms on the surface of iron nanocrystallite. The estimated value of the nitrogen diffusion coefficient varied exponentially with the degree of nitriding. In the area of the solution, the diffusion coefficient is approximately constant and amounts to 5 nm2/s. In the area of oscillatory changes, the average diffusion coefficient changes in the range of 3–11 nm2/s, and is inversely proportional to the nitrogen content degree. The advantage of the research method proposed in this paper is the possibility of simultaneously recording, under reaction conditions, changes in the values of several process parameters necessary to describe the process. The research results obtained in this way can be used to develop such fields of knowledge as heterogeneous catalysis, materials engineering, sensorics, etc.