Capillary Space Research Articles

An Insight into Perfusion Anisotropy within Solid Murine Lung Cancer Tumors.

Blood vessels are essential for maintaining tumor growth, progression, and metastasis, yet the tumor vasculature is under a constant state of remodeling. Since the tumor vasculature is an attractive therapeutic target, there is a need to predict the dynamic changes in intratumoral fluid pressure and velocity that occur across the tumor microenvironment (TME). The goal of this study was to obtain insight into perfusion anisotropy within lung tumors. To achieve this goal, we used the perfusion marker Hoechst 33342 and vascular endothelial marker CD31 to stain tumor sections from C57BL/6 mice harboring Lewis lung carcinoma tumors on their flank. Vasculature, capillary diameter, and permeability distribution were extracted at different time points along the tumor growth curve. A computational model was generated by applying a unique modeling approach based on the smeared physical fields (Kojic Transport Model, KTM). KTM predicts spatial and temporal changes in intratumoral pressure and fluid velocity within the growing tumor. Anisotropic perfusion occurs within two domains: capillary and extracellular space. Anisotropy in tumor structure causes the nonuniform distribution of pressure and fluid velocity. These results provide insights regarding local vascular distribution for optimal drug dosing and delivery to better predict distribution and duration of retention within the TME.

Correlation of light and electron microscopic morphometric parameters of glomerular capillaries with serum creatinine and proteinuria

ABSTRACT Waste products in the bloodstream are filtered by the glomerular capillaries in the kidneys and excreted into the urine. When making a differential diagnosis of kidney diseases, structural assessment of glomeruli using histological, ultrastructural, and immunological studies is crucial. This study assessed the microscopic and ultrastructural morphometric parameters of glomerular capillaries and examined their correlation with serum creatinine and proteinuria. A total of 60 kidney biopsy cases received by the transmission electron microscope (TEM) laboratory for diagnosis were included in the study. Toluidine blue stained 300 nm thick sections of TEM tissue blocks were scanned for glomerular morphometry by a whole slide imaging system, and the estimation of Bowman’s capsule (BC) area, glomerular capillary lumen diameter (GCLD), glomerular capillary density (GCD), glomerular capillary surface area density (GCSA), and percentage of glomerular capillary lumen space (%GCLS) was performed with QuPath software. TEM images of 70 nm thick sections were used for the evaluation of endothelial fenestration diameter (EFD), glomerular basement membrane (GBM) thickness, and podocyte foot process (PFP) effacement. Proteinuria and serum creatinine showed positive correlations with GBM thickness and PFP effacement. Negative correlations of serum creatinine were observed with EFD, %GCLS, and GCSA. Hence, glomerular filtration is greatly affected by the total area of the glomerular capillary surface and structural changes of GBM. Reduction of glomerulus filtration due to foot process effacement and thickening of GBM results in damage to the filtration barrier leading to the leakage of plasma protein into urine.

Experimental and modeling study of shear strength of unsaturated fine-grained soils with bi-modal water-retention characteristics

The mechanical behavior and strength characteristics of unsaturated fine-grained soils with dual-porosity are of crucial importance in geotechnical designs. Nanyang fine-grained soils have been selected as typical dual-porosity structure soils to perform experimental tests under a wide range of suction and different initial densities while studying its stress-strain-strength properties constitute the main scope of this study. Axial translation and vapor equilibrium techniques are jointly employed to apply a wide suction range. Our data suggest that soil behavior transits from strain-hardening with shear-induced contraction to strain-softening with shear-induced dilation as suction and density increase. By exploiting a bi-modal soil–water retention curve (SWRC) explicitly separating capillarity and adsorption mechanisms, the shear strength is allowed to be analyzed in the capillary suction stress-shear stress space. The strength envelop exhibits bi-linear characteristics. Building upon these findings, we propose a bi-linear shear strength criterion specifically for dual-porosity fine-grained soils. We utilize the obtained test data to evaluate existing strength criteria based on effective stress and dual stress variables that consider the bi-modal SWRC characteristics. The comparison indicates that the proposed bi-linear shear strength criterion can more reasonably represent the variation of shear strength under a wide range of suction for unsaturated dual-porosity fine-grained soils.

Relationship between soil and species diversity in typical forest stands in Xianrendong, Liaoning Province based on plant-soil feedback.

Exploring the relationship between soil properties and species diversity in typical forest stands in Liaoning Xianrendong National Nature Reserve will help maintain the stability of forest communities in the transition zone between flora in Changbai and North China. Based on the plant-soil feedback theory, community sample data from nine typical forest stands in the study area and experimental test data from 54 soil samples, we selected indexes of soil physical and chemical properties based on the minimum data set (temperature, compactness, capillary pore space, bulk weight, capillary water holding capacity, drainage capacity, soil water storage, conductivity, pH, organic matter, Ca, Fe, K, N and P). We adopt the research method of classical statistical analysis. The soil properties of nine typical stands in Xianrendong National Nature Reserve of Liaoning Province were systematically analyzed. The relationship between soil properties and forest stands' species diversity was quantified using correlation and redundancy analyses. The Pearson correlation analysis results showed significant positive correlations between the Gleason abundance index (arbors) with conductivity, pH, organic matter, Ca, N and P; Pielou's evenness index (arbors) with bulk weight and Fe. Significant negative correlations between the Gleason abundance index (arbors) with capillary pore space, bulk weight, drainage capacity, soil water storage and capillary water holding capacity; Simpson dominance index and Shannon-Wiener diversity index with capillary water holding capacity, drainage capacity and soil water storage; Pielou's evenness index (arbors) with Ca and N. The natural moisture content and clay particles are neutral feedback. The results showed that the feedback mechanism of soil physicochemical properties on stand species diversity was complex, which was conducive to species coexistence and community stability.

Acceleration of the Development of Microcirculation Embolism in the Brain due to Capillary Narrowing.

Cerebral microvascular obstruction is critically involved in recurrent stroke and decreased cerebral blood flow with age. The obstruction must occur in the capillary with a greater resistance to perfusion pressure through the microvascular networks. However, little is known about the relationship between capillary size and embolism formation. This study aimed to determine whether the capillary lumen space contributes to the development of microcirculation embolism. To spatiotemporally manipulate capillary diameters in vivo, transgenic mice expressing the light-gated cation channel protein ChR2 (channelrhodopsin-2) in mural cells were used. The spatiotemporal changes in the regional cerebral blood flow in response to the photoactivation of ChR2 mural cells were first characterized using laser speckle flowgraphy. Capillary responses to optimized photostimulation were then examined in vivo using 2-photon microscopy. Finally, microcirculation embolism due to intravenously injected fluorescent microbeads was compared under conditions with or without photoactivation of ChR2 mural cells. Following transcranial photostimulation, the stimulation intensity-dependent decrease in cerebral blood flow centered at the irradiation was observed (14%-49% decreases relative to the baseline). The cerebrovascular response to photostimulation showed significant constriction of the cerebral arteries and capillaries but not of the veins. As a result of vasoconstriction, a temporal stall of red blood cell flow occurred in the capillaries of the venous sides. The 2-photon excitation of a single ChR2 pericyte demonstrated the partial shrinkage of capillaries (7% relative to the baseline) around the stimulated cell. With the intravenous injection of microbeads, the occurrence of microcirculation embolism was significantly enhanced (11% increases compared to the control) with photostimulation. Capillary narrowing increases the risk of developing microcirculation embolism in the venous sides of the cerebral capillaries.

Capillary effect of layers of rubber-fabric composite

Rubber-fabric composites are a representative of a class of anisotropic reinforced composite laminates designed for operation in contact with a liquid medium. Each layer of the composite performs a specific function in the operation of printing machines. The rubber layer is located on the surface of the material and is impervious to hydrophilic liquids, but can swell to a limited extent in organic solvents. Layers of fabrics provide structural integrity and tension of the layered composite material and are protected from the penetration of the liquid medium by layers of rubber in a plane perpendicular to the arrangement of the layers. In a plane parallel to the arrangement of layers, the fabric is permeable to aqueous solutions and organic solvents. Permeability is based on the capillary effect of absorption. To eliminate the anisotropy of the permeability of reinforced composite layered materials, it is proposed to apply additional layers on the end surface that block the access of liquid to the capillary space through the pores, gaps between the threads and fibers of the fabric layers. An additional layer is applied by brushing or dipping into solutions of suspensions and emulsions of film-forming polymers: polyvinyl alcohol, polytetrafluoroethylene and acrylic polyester. The article describes an experimental technique for estimating porosity and calculating the average radius of capillaries using a physical model of the porous structure of the composite. The capillary pressure leading to absorption is described by Laplace's law. The laboratory stand is a modernized Klemm-Winkler device. The penetration of liquids into the porous structure of a composite rubber-fabric material through the end surface was measured. The sizes of pores in the structure of the composite, their number, volume, and the rate of filling of pores with water through the end surface in samples of anisotropic reinforced composite layered materials used in printing were calculated. A decrease in water permeability through protective layers on the end surface is shown depending on the chemical and phase composition of film-forming polymers. Diagrams of permeability, absorption kinetics and tables of porosity parameters of the rubber-fabric composite are compared. The proportions of capillaries of different diameters and their distribution over the cross-sectional area were determined.

A percolation-threshold model for evaluating permeability in Portland pastes with high water-cement ratio

In a perspective of improved sustainability, the definition of policies for the management of the heritage of concrete buildings and infrastructures, aiming at the suitable mitigation of the harm to environment and at the reduction of societal costs, requires reliable methodologies to estimate the service-life and maintenance periodicity time for a given class of concrete structures. Concrete watertightness is a basic property for assessing durability of the built heritage to weathering exposure and is mainly dependent on permeability of the cement paste embedding the aggregates which typically have much lower permeability in an ordinary concrete. Fundamental research of the past century has shown that a reliable experimental determination of permeability in Portland concretes and pastes can be achieved in terms of intrinsic permeability by uniaxial water-permeation tests under open-flow conditions.Powers and Brownyard have early assessed in 1947 the ability of the Kozeny-Carman relation in providing predictions of intrinsic permeability of Portland cement pastes, although achieving predictivity only below a water-cement ratio (w/c) of about 0.5. Above such threshold, as they observe, their model is no longer predictive since permeation through the capillary space formed due to excess water becomes predominant over permeation through the gel-space.In the present study an enhancement of Powers and Brownyard's canonical model is proposed by addressing capillary percolation and the possibility of simultaneous flow at the gel and capillary scales. The onset of capillary percolation for w/c slightly above 0.5 is naturally predicted. Agreement of the proposed model is assessed against experimental results and discussed in relation to optimal management of existing RC constructions with a view towards sustainability.

Hollow fiber membrane supported metal organic framework-based packed bed for gas/vapor adsorption

Crystalline metal–organic frameworks (MOFs) with high porosity have high sorption capacities for various gases. Their fragile and pulverulent characteristics have prompted significant efforts to prepare shaped bodies e.g., pellets, granules for use in adsorbers. A hollow fiber membrane-based strategy is adopted since hollow fiber membrane (HFM) modules are highly preferred for industrial separation processes due to very high surface area provided per unit device volume and their easy scalability. We report herein a solvothermal synthesis method whereby nanocrystals of the MOF, UiO-66-NH2, are synthesized directly inside submicron pores of hydrophilic hollow fiber membranes of Nylon 6 as well as in the bores of the HFMs. Nanocrystals of around 100 nm populate HFM pores. Cylindrical modules containing such HFMs and MOF nanocrystals and microcrystals in membrane pores, HFM bores and the extra capillary space were studied for adsorption of ammonia from a dilute gas stream. High values of ammonia breakthrough time were achieved. The corresponding behaviors of three MOF configurations namely, MOF in membrane pores, MOF in membrane pores and the HFM bores and MOF present in membrane pores, HFM bores and in extra capillary space were studied. The values of time/MOF weight achieved were very high. The MOFs synthesized were characterized by Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffractometer (PXRD), Brunauer-Emmett-Teller (BET) adsorption isotherms, surface area, and pore size distribution. High performance of HFM-supported MOF-based scalable devices for gas/vapor adsorption has been demonstrated with values of 20,000 min/g of MOF for trace ammonia breakthrough from humid ammonia feed gas stream employed. Other potential uses of such devices for adsorbing 2 to 3 gases and liquid phase adsorption have also been discussed.

Optimization of eco-friendly Pinus resinosa biochar-dodecanoic acid phase change composite for the cleaner environment

The use of waste materials in sustainable energy forms has gained a tremendous research focus, which has risen the trend of energy demand coupled with environmental concerns. Contemplating that, biochar material from organic waste has been considered as shape stabilizing materials for the organic phase change materials (PCMs) aiming for thermal energy storage (TES) applications. Pinus resinosa (PR) fruits have been pyrolyzed into biochar which has exhibited a highly porous and channel-like morphology with a surface area of 27.99 m2/g. Dodecanoic acid (DA) in 1:1, 2:1, 3:1, and 4:1 ratios have been incorporated into the PR biochar for the fabrication of shape-stabilized phase change composites (DAPR). The highest melting and solidification enthalpies are exhibited by the DAPR-4 composite, though the values are almost similar to the DAPR-3 composite. Therefore, 3:1 DA to PR biochar can be considered as the optimum ratio. The maximum encapsulation efficiency and ratio are calculated to be 32.53 % and 32.66 %, respectively while the highest melting enthalpy is obtained at 50.87 J/g. All the DAPR composites have demonstrated admirable leakage-proof performance at elevated temperatures along with the congruent thermal cycle resilience up to 100 cycles of heat charging and discharging, without any alteration in temperatures and enthalpies. The exceptional thermal and structural stabilities manifested by the DAPR samples are ascribed to the capillary action, surface functionality, and space confinement effects of the biochar.

Multiscale modelling of brain tissue oxygen and glucose dynamics in tortuous capillary during ischaemia-reperfusion

Brain ischaemia causes reduction of cerebral blood flow, which interrupts the transport of oxygen and glucose to brain tissue. These transport inefficiencies have also been associated with the complex cerebral microvasculature. In this study, the importance of cerebral capillary complexity and tissue interstitial porosity in oxygen and glucose transport and metabolism during brain tissue ischaemia is investigated using an asymptotic expansion homogenization method. Applying this technique produces new macroscale governing equations with associated microscale cell problems. Solving the latter on the brain tissue microstructural geometry will obtain parametric tensors, namely the conductivities of the capillary, K and interstitial space, E; and the diffusivities of a substrate in the capillary, DM,c, and in interstitial space, DM,t. From the microscale simulations, increasing the capillary tortuosity resulted in a decrement of K and DM,c, but no significant changes in E and DM,t. Meanwhile, increasing the capillary radius resulted in the decrease of all parameters except K. Then, the parametric tensors obtained are used to solve the macroscale governing equations on a one-dimensional brain model under ischaemia-reperfusion conditions. From the macroscale simulations, changing the capillary tortuosity affects the uptake and metabolism of oxygen and glucose during brain ischaemia-reperfusion. In addition, in more tortuous capillaries, oxygen and glucose are utilized rapidly at tissues proximal to the capillary during the reperfusion process, leaving only a small amount of these substrates for distal tissues. This could be associated with severe stroke outcome. It is thus proposed that the capillary tortuosity of a patient could potentially be used as an additional indicator in determining the severity of ischaemic stroke.

Improved capillary rheometry for viscous Newtonian filaments

The efficacy of the kinematic differential analysis of McCarroll et al. [“Differential analysis of capillary breakup rheometry for Newtonian liquids,” J. Fluid Mech. 804, 116 (2016)], expanding on McKinley and Tripathi [“How to extract the Newtonian viscosity from capillary breakup measurements in a filament rheometer,” J. Rheol. 44, 653 (2000)], to evaluate the surface tension to viscosity ratio for Newtonian filaments is examined. The analysis is valid during and after stretch, while the latter is traditionally applied after cessation of stretch as the midfilament radius approaches zero. Through numerical simulations, the evaluation of viscosity is investigated for two common stretch histories: (a) the ramp function and (b) the modified step strain. The challenges with stretch are twofold: rapid stretch (large capillary number) results in a nearly cylindrical filament with a rapid change near the plate that challenges the one-dimensional (1D) approximation, while slow stretch results in a nearly static solution with limited viscous information. We examine the capillary number-aspect ratio parameter space and find the ramp function with small stretching speeds optimal. Hence, the most accurate measurements are taken while the filament is being stretched.

Live Tissue Imaging Reveals Distinct Transcellular Pathways for Organic Cations and Anions at the Blood-Cerebrospinal Fluid Barrier.

Formed by the choroid plexus epithelial (CPE) cells, the blood-cerebrospinal fluid barrier (BCSFB) plays an active role in removing drugs, toxins, and metabolic wastes from the brain. Several organic cation and anion transporters are expressed in the CPE cells, but how they functionally mediate transepithelial transport of organic cations and anions remain unclear. In this study, we visualized the transcellular transport of fluorescent organic cation and organic anion probes using live tissue imaging in freshly isolated mouse choroid plexuses (CPs). The cationic probe, 4-[4-(dimethylamino)phenyl]-1-methylpyridinium iodide (IDT307) was transported into CPE cells at the apical membrane and highly accumulated in mitochondria. Consistent with the lack of expression of organic cation efflux transporters, there was little efflux of IDT307 into the blood capillary space. Furthermore, IDT307 uptake and intracellular accumulation was attenuated by approximately 70% in CP tissues from mice with targeted deletion of the plasma membrane monoamine transporter (Pmat). In contrast, the anionic probe fluorescein-methotrexate (FL-MTX) was rapidly transported across the CPE cells into the capillary space with little intracellular accumulation. Rifampicin, an inhibitor of organic anion transporting polypeptides (OATPs), completely blocked FL-MTX uptake into the CPE cells whereas MK-571, a pan-inhibitor of multidrug resistance associated proteins (MRPs), abolished basolateral efflux of FL-MTX. In summary, our results suggest distinct transcellular transport pathways for organic cations and anions at the BCSFB and reveal a pivotal role of PMAT, OATP and MRP transporters in organic cation and anion transport at the blood-cerebrospinal fluid interface. SIGNIFICANCE STATEMENT: Live tissue imaging revealed that while organic cations are transported from the cerebrospinal fluid (CSF) into the choroid plexus epithelial cells by plasma membrane monoamine transporter without efflux into the blood, amphipathic anions in the CSF are efficiently transported across the BCSFB through the collaborated function of apical organic anion transporting polypeptides and basolateral multidrug resistance associated proteins. These findings contribute to a mechanistic understanding of the molecular and cellular pathways for choroid plexus clearance of solutes from the brain.

Trans-, Translation, Transnational

Trans-, Translation, Transnational

Морфологічні зміни головного мозку при діабетичній енцефалопатії

Метою наведеної роботи було вивчення морфологічних характеристик змін головного мозку у хворих із діабетичною енцефалопатією (ДЕ) на підставі дослідження аутопсійного матеріалу. Матеріали та методи. В роботі наведено результати 14 секційних спостережень. Середній вік хворих становив 51,0 ± 3,4 року. Шматочки мозку фіксували в розчині IHC Zink Fixative, виготовляли серійні парафінові зрізи товщиною 10 ± 1 мкм. Препарати фарбували гематоксиліном і еозином, конго рот, тіоніном за методом Ніссля, ставили ШИК-реакцію, імпрегнували нітратом срібла за методом Більшовського і хлоридом золота за Кахалем, проводили морфометричне дослідження за Г.Г. Автанділовим. Препарати досліджували на мікроскопі Olympus AX70 з цифровою камерою Olympus DP50. Мікрофотографування препаратів здійснювалося з використанням програми AnalysisPro 3.2. Результати. Основними цито-ангіоархітектонічними проявами ДЕ є дифузна альтерація базальних мембран і ендотелію судин мікроциркуляторного русла, меншою мірою — артеріол, внутрішньомозкових артерій і вен. Висока щільність (питомий обсяг) капілярної мережі при ДЕ морфологічно відображає картину капілярного паралітичного застою. Капілярний застій супроводжується стазом крові, збільшенням навколосудинного капілярного простору (простір Вірхова — Робіна), ширина якого є морфологічним еквівалентом лімфатичної дисциркуляції. Ранні морфологічні ушкодження стінок капілярів — потовщення і розщеплення основної мембрани з накопиченням ШИК-позитивних речовин, вогнищева проліферація ендотеліоцитів. До пізніх пошкоджень відносяться капілярний фіброз і гіаліноз, проліферація перицитів, що супроводжується різким порушенням транскапілярного транспорту. Порушення стріарної і радіарної цитоархітектоніки в I–IV шарах головного мозку, випадіння нейронів (нейрональні спустошення) проявляються вогнищевим випадінням гангліозних і пірамідальних клітин. Висновки. Ранніми зворотними морфологічними змінами нейронів є набухання нейронів (гідропічна дистрофія нервових клітин), вогнищевий гіперхроматоз. Незворотними структурними ушкодженнями нейронів є лізис ядра і ядерця з гомогенізацією цитоплазми, формування клітин-тіней, вакуолізація цитоплазми, перицелюлярний набряк, лізис відрост­ків у поєднанні з нейрофагією. Є характерним поєднання гострих альтернативних ушкоджень нейронів із хронічними (ішемічного характеру) — пікноз, зморщування ядер з вираженою атрофією цитоплазми.

Effects of channel geometry and physicochemical properties of solutions on stable double emulsion production in planar microfluidic devices having triangular orifices

The planar microfluidic devices for producing double emulsions are beneficial in terms of accuracy and facility in fabrication. However, factors such as the flow rates, interfacial tensions, viscosities, channel geometry, and wettability of the devices affect the stability of the double emulsion production. In this study, we have focused on double emulsion production in a planar flow focusing device with triangle-shaped orifices. The local velocity in the channel can be controlled by modifying the channel design. Here, we have used two types of microfluidic devices with orifices and junctions of different shapes, denoted as mc-A and mc-B. By controlling the orifice angles and the width of the junctions, the stable flow regimes characterized in a capillary number space were expanded, and the production efficiency was increased. The effects of interfacial tensions of the sample solutions on the stability of double emulsion production were also examined. The double emulsions produced under stable conditions were highly uniform, and the diameter of the produced emulsions was well defined by the capillary numbers. However, the diameter of the double emulsions was mainly affected by the size of the orifice.

Fabrication of a Novel Protein Sponge with Dual-Scale Porosity and Mixed Wettability Using a Clean and Versatile Microwave-Based Process.

An open-porous protein sponge with mixed wettability is presented made entirely from whey proteins and with promising applications in biomedicine, pharmaceutical, and food industry. The fabrication relies on an additive-free, clean and scalable process consisting of foaming followed by controlled microwave-convection drying. Volumetric heating throughout the matrix induced by microwaves causes fast expansion and elongation of the foam bubbles, retards crust formation and promotes early protein denaturation. These effects counteract collapse and shrinkage typically encountered in convection drying of foams. The interplay of high protein content, tailored gas incorporation and controlled drying result in a dried structure with dual-scale porosity composed of open macroscopic elongated foam bubbles and microscopic pores in the surrounding solid lamellae induced by water evaporation. Due to the insolubility and mixed wettability of the denatured protein network, polar and non-polar liquids are rapidly absorbed into the interconnected capillary system of the sponge without disintegrating. While non-watery liquids penetrate the pores by capillary suction, water diffuses also into the stiff protein matrix, inducing swelling and softening. Consequently, the water-filled soft sponge can be emptied by compression and re-absorbs any wetting liquid into the free capillary space.

Helium physico-chemical «recruitment» of pulmonary alveols in prevention of alveolar collapse and prevention of acute respiratory distress syndrome in patients with severe COVID19 pneumonia

Purpose . Show the significance of helium heated to 95°C (as part of Thermogeliox) in reducing the surface tension of water, including the liquid and cellular fraction of blood, which normalizes the movement of red blood cells in the capillaries and preserves the physiological function of the alveolar — capillary space, improving gas exchange in the alveoli. Materials and methods . The data on the dynamics of complaints and anamnesis, clinical symptoms, results of laboratory and instrumental studies, the results of pathological, pathomorphological and histological manifestations of severe coronavirus pneumonia (CVP) complicated by acute respiratory distress syndrome (ARDS) were analyzed. Results and its discussion . In the complex treatment of severe coronavirus infection (CVI), it is proposed to use the modern innovative medical technology «SIMT», which includes a modern device «Ingalit B2–01», inhaling a respiratory gas mixture heated to 90–100°C — thermogeliox, consisting of oxygen 20–30% and helium 70–80%, alternating with inhalation of pulmonary surfactant by a nebulizer. It is advisable to inject the anticoagulant under the skin. It has been shown that the development of ARDS in CEP is associated with acute coronavirus alveolitis. A quick positive systemic therapeutic effect — the prevention of ARDS in patients with severe CVP when using our proposed «SIMT» is due to a number of physicochemical and physiological effects of thermal helium.

Investigation on the microstructure-related characteristics to elucidate performance of composite cement with limestone-calcined clay combination

This paper discusses the role of physical structure alterations on three binder types: plain portland cement, fly ash-based binder and calcined clay-limestone binder. The kinetics of physical structure development and the relevance in transport properties were distinguished using an interlinked parameter in concrete and paste. A systematic experimental investigation was carried out on a range of critical parameters such as strength development, resistivity development, transport characteristics and the time-dependent change in transport parameter. The role of microstructure in terms of the chemical composition of C-A-S-H and its physical states in the different systems is identified as the critical factor governing the development of microstructure. Chloride resistance was assessed by chloride migration experiments for a period of 4 years. The durability behaviours of the concrete with various binder were generalised using pore network parameters such as formation factor and tortuosity. A sensitivity analysis was used to dissect the contribution of the pore solution dilution and pore connectivity to the change in the pore network parameter.Based on the rise in macroscopic physical characteristics (i.e., formation factor here), a two-fold structure development mechanism to conceptualise microstructural evolution in cement composites is presented. Initially, capillary pore space reduces to a critical size range (i.e., 10–30 nm), which is followed by the densification of the physical state of the microstructure. At the point of densification, the pores become largely disconnected which leads to a dramatic increase in the formation factor. The binding matrix in calcined clay concretes reaches the critical pore size at an early age which leads to early densification of capillary pore space region in comparison to fly ash concretes.

On the Issue of the Influence of Interfacial Interactions on the Filtration Processes in Coal

The features of gas-liquid fluid filtration processes in a coal mass are discussed and general patterns of mass transfer, extending previously known concepts, are established in the article. It indicates the degree of the influence of wettability, contact angle of wetting on filtration processes. It is assumed the coal-liquid-gas interfacial interactions when infusing the coal mass lead to the deformation of capillary pore space of coal, splitting, swelling and clogging of filter pores and capillaries. A comparison is made between the thermal effect and the effect of surfactants on the deformation processes of the capillary-porous structure of coal. Filtration processes are described by the gas-liquid fluid mass transfer equations. Coal-liquid-gas interfacial processes lead to a change in the state of the interacting phases, which leads to a change in both the filtration properties of the liquid and the filtration properties of a capillary pore space, which is especially characteristic of coal in relation to other rocks. Investigating the interfacial interactions when filtering in the laboratory, it is possible to determine the functions of the variation of the key coefficients in the mass transfer equations. On the basis of such studies, it is possible to predict the results of mass transfer in a coal mass being infused or degassed, as well as the change in the coal mass stress state.

A Case Report of a Tongue Ulcer as a Rare Presentation of Oral Hemangioma

Oral hemangioma is a rare benign vascular tumor. It may occur on lips, tongue, buccal mucosa, and palate. Hemangioma is a congenital hamartoma and its clinical presentations and patients’ history aid in its diagnosis. Histopathologically, hemangioma shows flatted endothelial cells and small capillary size space. In this report, we will describe a rare presentation of oral hemangioma as an asymptomatic tongue ulcer in a 32-year-old woman. The clinical presentation, differential diagnosis, and management will also be described in detail.