Capillary Tube Research Articles

Konjac glucomannan foams integrated with bilayer phase change microcapsules for efficient heat storage and thermal insulation.

Konjac glucomannan foams integrated with bilayer phase change microcapsules for efficient heat storage and thermal insulation.

Advanced Manufacturing Methods for High-Dose Inhalable Powders

Pulmonary drug delivery is governed by three main categories of forces: interparticle forces in the powder formulation, the dispersion forces during inhalation by the device, and deposition forces in the lungs. The interaction between fine inhalable powder particles of the active ingredient is governed by various types of forces, such as capillary forces, electrostatic forces, and van der Waals forces. The different types of inter-particle interactions influence the balance between powder dispersibility and agglomerate stability. The high level of cohesion forces arising from high surface energy of very fine powder hinders powder flowability, leading to issues of agglomeration. Therefore, there is a critical need for advanced manufacturing techniques to overcome the challenges of handling and manufacture of fine cohesive particles, particularly high-dose powders for inhalation. This review will focus on the challenges facing the formulation process of very fine inhalable powder, the various types of existing particle engineering techniques for high-dose powder inhalers, and the characterization techniques employed to analyse the powder characteristics required to meet the acceptance criteria of inhalable preparations.

Cascaded Gravity-Driven Microfluidic Chip with Tilt-Actuated Siphon Valves for Rapid Detection of Salmonella Typhimurium.

In recent years, urgent food safety issues have heightened the demand for rapid detection technologies for foodborne pathogens, especially biosensors featuring simplicity, rapidity, and high sensitivity. Yet despite a booming surge in related published studies, commercializing these biosensors remains a constant challenge and persistent objective for researchers. In this study, a gravity-driven microfluidic chip with tilt-actuated siphon valves was developed, integrating silica magnetic beads based nucleic acid separation and recombinase-aided amplification (RAA) detection of Salmonella Typhimurium by simple operations along with a portable biosensing device. By chip inclination, the balance between gravity of reagents and capillary force around siphon valves is altered; thus, simple tilting operations could provide a driving force for fluid flow without the need for external pumps. Siphon valves were designed geometrically with surface modifications to generate comfortable tilting angles, and a chip holder with a built-in angle guide was designed to ensure consistent operational performance. A smartphone app was developed to monitor fluorescence signals for quantitative detection of S. Typhimurium. Experimental results showed that this portable biosensing device could detect S. Typhimurium in spiked chicken samples at concentrations as low as 1.1 × 101 CFU/mL within 60 min, with recovery rates ranging from 91.54% to 117.27%. The siphon valves also demonstrated compatibility with diverse liquid properties, offering scalability and adaptability for various detection scenarios and potential for the detection of various pathogens in food safety and clinical diagnostics by using related nucleic acid probes and reagents.

Improvement of hydrophysical properties of modified heavy-duty concrete working in severe operating conditions

Requirements for concrete used in the manufacture of structures operating in harsh operating conditions are different from those for concrete used in industrial and civil construction. Such special requirements are primarily due to difficult operating conditions, in particular for tunnel structures. Under the influence of a whole range of aggressive environmental factors, this type of structure is partially or completely destroyed, which in turn reduces their design service life. Therefore, a necessary condition for increasing their durability is the creation of a modified dense concrete structure with improved hydrophysical properties: low rates of water absorption, capillary suction, water resistance and high frost resistance. Currently, there are developments in strengthening and protecting such structures with materials with an increased degree of resistance to aggressive factors, for example, polymer compositions. However, polymer concretes have not found wide distribution due to their scarcity and high cost, so today the main building material in the construction of tunnel structures remains concrete and reinforced concrete. Thus, obtaining heavy concretes operating in harsh conditions with increased performance properties by modifying its structure is an urgent task. Objective: To establish the positive effect of complex modification together with a micro-reinforcing component on the hydrophysical properties of heavy concrete. Object: heavy concrete with a complex modifier (superplasticizer + polymer + metakaolin), reinforced with wollastonite for tunnel structures. Research results: A positive effect of complex modification on the properties of heavy concrete was established by reducing the content of binder (cement) and replacing it with metakaolin, which allows improving the hydrophysical characteristics: water absorption - 1.8%; water resistance grade - W14, with a sufficient margin of safety and frost resistance (F more than 600 cycles), which makes it possible to use this composition in practice to obtain building structures with specified characteristics operating under high loads and an aggressive environment, in particular, for tunnel structures.

Enhancing the Design of Microdevices: The Role of Computational Fluid Dynamics and Experimental Investigation

The growing use of microfluidic-based devices necessitates an analysis of flow characteristics through both experimental methods and computational fluid dynamic (CFD) simulations. CFD simulations facilitate the investigation of various devices, including medical sensors, by providing detailed insights into flow behavior. In this study, we conducted experimental and CFD analysis of the microfluidic flow in three devices: a COVID-19 rapid test kit, a blood glucose kit, and a PDMS kit. Our findings revealed that the changes in wall adhesion (contact angles) during the capillary flow could cause significant deviation from theoretical flow speed predictions. A hemodynamic analysis of the blood glucose kit and PDMS kit showed that capillary filling decreased in length, and flow speed could depend on the microchannel diameter. CFD results indicated the prominent role of porosity in the simulation of porous media material such as the COVID-19 test kit, as well as surface tension coefficients and wall adhesion (contact angles) in blood glucose kits and PDMS kits. Therefore, considering adaptive dynamic contact angles in CFD simulation software such as Ansys-Fluent 2024 could result in a more accurate prediction than simplified theoretical techniques, which is useful for sensor optimization and development.

Capillary flow in corners slowed down by gravity and evaporation

Abstract Capillary flow in corner geometries in the presence of gravity and evaporation is relevant for numerous natural phenomena and industrial applications. In the absence of gravity, the length of the rivulet in the corner follows the t 1/2 asymptotic law (Lucas-Washburn kinetics), where t is the time. If the liquid flows against gravity, the propagation of the rivulet tip decelerates to follow the t 1/3 asymptotic law. In this paper, we present a model for simulation of the rivulet shape evolution in a corner with an arbitrary cross-section shape. Gravity and evaporation are taken into account. Several exact and asymptotic solutions are presented. In particular, a simple expression for the proportionality coefficient in the t 1/3 asymptotic law is derived, as well as an expression for the cross-over time moment corresponding to change from the t 1/2 to t 1/3 asymptotic behavior. In the presence of evaporation, the rivulet length reaches a maximal value, at which the rate of evaporation is balanced by the rate of the capillary flow. We derive expressions for the maximal rivulet length in the limiting cases of “strong” and “weak” evaporation. In the case of “strong” evaporation, the maximal rivulet length behaves as E −1/2, where E denotes the dimensionless evaporation rate. In the case of “weak” evaporation, uniform evaporation rate and triangular groove geometry, the maximal rivulet length is proportional to E −1/5 Bo −3/5, where Bo denotes the Bond number.

Acute kidney injury triggers hypoxemia by lung intravascular neutrophil retention that reduces capillary blood flow.

Sterile acute kidney injury (AKI) is common in the clinic and frequently associated with unexplained hypoxemia that does not improve with dialysis. AKI induces remote lung inflammation with neutrophil recruitment in mice and humans, but which cellular cues establish neutrophilic inflammation and how it contributes to hypoxemia is not known. Here we report that AKI induces rapid intravascular neutrophil retention in lung alveolar capillaries without extravasation into tissue or alveoli, causing hypoxemia by reducing lung capillary blood flow in the absence of substantial lung interstitial or alveolar edema. In contrast to direct ischemic lung injury, lung neutrophil recruitment during remote lung inflammation did not require cues from intravascular non-classical monocytes or tissue-resident alveolar macrophages. Instead, lung neutrophil retention depended on neutrophil chemoattractant CXCL2 released by activated classical monocytes. Comparative single-cell RNA-sequencing analysis of direct and remote lung inflammation revealed that alveolar macrophages are highly activated and produce CXCL2 only in direct lung inflammation. Establishing a CXCL2 gradient into the alveolus by intratracheal CXCL2 administration during AKI-induced remote lung inflammation enabled neutrophils to extravasate. We thus discovered important differences in lung neutrophil recruitment in direct versus remote lung inflammation and identified lung capillary neutrophil retention that negatively affects oxygenation by causing a ventilation-perfusion mismatch as a driver of AKI-induced hypoxemia.

Regional cutaneous blood flow in healthy subjects under conditions of 21-day head-down bed rest

Introduction. Research into the microvasculature as an integral component of the cardiovascular system is particularly relevant in space medicine for identifying adaptive changes to weightlessness and developing new diagnostic criteria for assessing the functional state of an astronaut’s body in long-duration space flights.Objective. To study the process of microcirculation and its regulation in various skin areas in healthy volunteers under conditions of 21-day head-down (–6°) bed rest (HDBR).Materials and methods. The experiment involved six male volunteers aged 26–34 years. To simulate translocation of liquid media and physical inactivity, the subjects remained in an antiorthostatic position for 21 days. Microcirculation was studied by laser Doppler flowmetry using LAZMA PF portable laser analyzers (SPE “LAZMA” Ltd, Russia). Participant examination was conducted two days prior the onset of the study, on the 3rd, 7th, 15th, 18th, and 20th day of experimental exposure, as well as two days after the completion of HDBR. Statistical data analysis was performed using the Statistica 13.0 software (IBM, USA).Results. On day 3 of HDBR exposure, a statistically significant decrease in basal perfusion and the amplitude of myogenic oscillations in the skin of the forehead and shin was observed. The analysis of functional tests on the forearm showed a decrease in the respiratory test index by 10.87% throughout the experimental period. On day 3 of hypomobility, a decrease in the venuloarteriolar response by an average of 10.64% and an increase by 91.82% in the capillary blood flow reserve were noted, with the latter persisting throughout the entire exposure.Conclusions. The effect of HDBR is expressed in a decrease in skin perfusion against the background of increased tone of terminal arterioles and precapillary sphincters in the forehead and lower legs, which may indicate microcirculation shift toward larger vessels. Despite the skin perfusion stability in the forearm area at rest, the conducted functional tests showed the probability of changes in vasomotor function under the action of HDBR.

Numerical Simulation of Natural Gas Hydrate Depressurization Extraction Considering Phase Transition Characteristics

Natural gas hydrate (NGH) is a clean resource characterized by abundant potential reserves, clean combustion, and high energy density. Although significant progress has been made in the development of NGH resources all around the world, challenges still exist that hinder commercial exploitation, such as a low daily gas production rate and short steady production periods. One significant reason lies in the complex gas–liquid–solid phase transitions occurring within the formation during production, which lead to changes in flow capacity. Understanding the phase change mechanism of NGH reservoirs will help to further reveal the production increase mechanism. To address the phase transitions’ effect on production, this paper establishes a numerical simulation model for the depressurization exploitation of natural gas hydrates in order to investigate phase transition characteristics at the field scale. First, the phase equilibrium calculation method is presented and the phase equilibrium curve is modified by considering the capillary effect, soluble salt, and surface adsorption. Then, the phase transition model is successfully characterized in a simulation and the numerical simulation model is established based on the first test project parameters in the Shenhu area. The production characteristics of different sediment types (montmorillonite, South China Sea sediments, kaolin, and silt) are analyzed under the effects of water content and salinity. It is shown that lower initial water content and higher salinity result in higher gas production. The results provide a better understanding of the effects of phase transition parameters on NGH production at the field scale.

Transforming Plastic Waste into Fashionable Dresses: An Exploratory Approach for Sustainable Management

Purpose: This study tries to make clothing appealing and sustainable from plastic waste. Design/Methodology/Approach: An in-depth interview was done using (30) people across recycling companies to examine the challenges in recycling plastics in Ghana. Clothing was designed to pay particular attention to the amount of plastic waste used. A cross-sectional quantitative study was done to sort opinions on the possible uses of plastic using one hundred and fifty (150) fashion students. Another cross-sectional quantitative study used one hundred and fifty (150) fashion students to determine the acceptability of clothing made from plastic waste material. Findings: The results showed that the challenge faced in recycling plastic is the high cost associated with the materials and equipment required for recycling. Producing clothing from plastic waste can contribute significantly to reducing plastic waste. Sportswear is the most preferred clothing item from recycled plastic waste. Research Limitation: The research is geographically restricted to the Greater Accra of Ghana. The type of plastic waste material obtained and used in clothing production is limited to plastic waste material generated within the Greater Accra of Ghana. The acceptance of clothing made from plastic waste material is also limited to the researcher’s design presented to participants. Practical Implication: The research transformed plastic waste into usable clothing and examined its acceptability. This provided insights into consumer-acceptable clothing that can be made from recycled plastic waste. Social Implication: The study quantifies how much plastic waste can be recycled into a particular fabric and provides an idea of the quantity of plastic waste that can be removed from the environment based on the number of clothing produced. Originality/Value: The work also employed different methods to make plastic suitable for fabric production and blended recycled plastic with traditional fabrics, which were incorporated into the clothing design. Plastics from their original state were altered to different textures to allow the plastic to be cut into different designs and to fit a particular design for which the plastic waste fabric was used. Textile testing evaluated characteristics like tensile strength, abrasion resistance, shrinkage, breathability, and moisture wicking.

Characterization of Fibrinolytic Enzyme from Bacillus altitudinis S-CSR 0020 and Its Clot-Degrading Capacity.

Thrombosis, the major cause of heart disease, is on the rise owing to the current lifestyle habits of the population. Current treatments using thrombolytics, although successful, are plagued by side effects and costs. Fibrinolytic enzymes derived from microbial sources are ideal substitutes for chemical thrombolytics. Bacillus altitudinis S-CSR 0020, a soil bacterium, was shown to efficiently produce fibrinolytic enzyme. In this study, we further purified the enzyme using a combination of ammonium sulfate precipitation and ion-exchange chromatography to achieve a purification fold of 7.8 and a yield of 7%. SDS-PAGE and zymogram analysis revealed that the enzyme was 95kDa in size and exhibited high stability across a broad pH range (6-11) and high temperature (30-60℃) even after 24h incubation, along with an optimum pH and temperature of 9 and 40°C, respectively. Further characterization revealed that the fibrinolytic activity was maximum at 4% fibrin concentration, and 3% ferric chloride and 5% β-mercaptoethanol enhanced enzyme activity. Functional analysis revealed that the purified enzyme efficiently removed preformed clots in the capillary and microfuge tubes and exhibited anticoagulant activity. No adverse effects were observed in the goat hepatic portal vein upon application of the fibrinolytic enzyme. This enzyme also displayed antibacterial activity against Staphylococcus aureus. The anticoagulant, clot-degrading potential, and non-toxic nature of the purified fibrinolytic enzyme highlight its potential application in the treatment of thrombosis.

Angiogenic factor AGGF1 is a general splicing factor regulating angiogenesis and vascular development by alternative splicing of SRSF6.

AGGF1 encodes an angiogenic factor that causes vascular disease Klippel-Trenaunay syndrome when mutated. AGGF1 also acts at the top of the genetic regulatory hierarchy for mesodermal differentiation of hemangioblasts, multipotent stem cells for differentiation of blood cells and vascular cells. Alternative splicing (AS) is a post-transcriptional process that generates multiple mature mRNAs from a single primary transcript (pre-mRNA), producing protein diversity. Deregulation of AS leads to many human diseases. The physiological role and mechanism of AGGF1 in AS are not clear. Full-length transcriptome sequencing of human pulmonary artery endothelial cells (HPAECs) with AGGF1 silencing revealed 63 121 genes, including 1144 new unannotated genes, and showed that AGGF1 is a general splicing factor regulating AS of 436 genes, including SRSF6 regulating AS of many target genes. AGGF1 promoted the skipping of exon 3 that produces the full-length SRSF6 protein, an evolutionarily conserved AS event. Overexpression of full-length SRSF6 reversed the reduced cell proliferation, migration, and capillary tube formation of HPAECs with AGGF1 silencing. Knockdown of SRSF6 and overexpression of the shorter, alternatively spliced isoform of SRSF6 both inhibited HPAEC proliferation, migration, and capillary tube formation, whereas opposite results were obtained for overexpression of full-length SRSF6. Knockdown of srsf6 impaired development of ISVs in zebrafish, whereas overexpression of srsf6 enhanced vascular development and partially rescued impaired ISV development in zebrafish embryos with aggf1 knockdown. Overall, our findings reveal that AGGF1 is a general splicing factor, and that AGGF1-mediated exon 3 skipping of SRSF6 pre-mRNA is important for endothelial cell functions, angiogenesis, and vascular development.

Hemoglobin Mass Determination: Exploring Carboxyhemoglobin Stability and Analyzer Interchangeability.

Carbon monoxide (CO) rebreathing is frequently used to determine hemoglobin mass (Hbmass) during hypoxic or heat training and high-altitude research. Accurate and reliable carboxyhemoglobin (HbCO) determination is crucial for reliable Hbmass measurements. The aim was therefore to explore the stability of HbCO and interchangeability of two Radiometer analyzers in the determination of Hbmass. Twelve subjects performed a CO rebreathing test. Five capillary blood samples were taken before and after the CO rebreathing test and either analyzed immediately on site (three capillary tubes, Day 1, ABL 90) or stored at room temperature and sent to another laboratory for analysis 4-8 days later (two capillary tubes, ABL 825). Intraclass correlation coefficient (ICC) and relative typical error (TE) were calculated to compare both measurements. A paired sample t test was performed to detect potential differences between Day 1 (ABL 90) and Days 4-8 (ABL 825). A trivial mean difference was observed between the two measurements for ΔHbCO (0.05%, p = 0.01, d = -0.12) and Hbmass (7.7 g, p = 0.01, d = 0.10). High reliability (ICC > 0.98) and low TE (< 0.91%) were found for ΔHbCO and Hbmass. Immediate analysis with the same analyzer remains recommended despite trivial differences between measurements. However, when logistical issues (analyzer breakdown, extreme, and/or remote locations) do not allow optimal procedures, delayed analysis, potentially with a different analyzer, might be used as a viable alternative.

A Generic Detection Method for the Doping Control Analysis of Fc-Fusion Proteins and Monoclonal Antibodies in Equine Plasma.

An increasing number of novel Fc-fusion proteins and monoclonal antibodies (mAbs) are being developed as therapeutic agents for treating various diseases. Among these, there are inhibitors of the activin Type II receptor (ActRIIA and ActRIIB) signaling pathways and mAbs against nerve growth factor (NGF), which may be misused for performance enhancement in horseracing and equestrian sports. This study is aimed at developing a generic detection method for doping control analysis of nine targeted proteins, each containing the Fc domain of human IgG or IgG from other species in equine plasma, namely, three recombinant Fc-fusion proteins (sotatercept, follistatin-Fc (FST-Fc), and erythropoietin-Fc (EPO-Fc)) and six mAbs (bimagrumab, domagrozumab, garetosmab, landogrozumab, bedinvetmab (Librela), and frunevetmab (Solensia)). A generic workflow has been developed, involving affinity purification with commercially available Protein A magnetic beads followed by tryptic digestion and detection of 20 targeted peptides (with 2-3 diagnostic peptides for each targeted protein) using capillary flow high-performance liquid chromatography-high-resolution tandem mass spectrometry (HPLC-HRMS). The method identified all nine targeted proteins in spiked equine plasma with adequate sensitivity and precision, and for the first time, bedinvetmab (Librela) was detected and identified in plasma for at least 34 days after a single subcutaneous administration (0.5 mg/kg) to a Thoroughbred horse. The results have demonstrated the method's applicability to equine doping control. This generic method involving affinity purification by Protein A has provided a pragmatic and effective approach to cope with the doping control of novel Fc domain-containing proteins.

Construction of a model of subsoil moisture movement in cultivated slope lands

Insufficient study of the dynamics of moisture movement both in the soil loosened by the tillage tool and in the zone of uncultivated subsoil wall in the conditions of moisture deficient south of Russia necessitated for development of a mathematical model of subsoil moisture transfer. A distinctive feature of this model is the study of moisture transfer in the zone of the upper soil layer of 0.60 m by the developed universal tillage tool for cultivating of sloping and plain lands. To study the moistening process in the slope soil layer treated by the new method, the following assumptions were made: the soil skeleton was geometrically unchanged; hysteresis was excluded in the system under consideration; the moisture inside the soil was not compressed; the air pressure inside the treated soil horizon was equal to the atmospheric pressure; capillary and gravitational phenomena were the main causes of moisture movement inside the treated layer; subsoil moisture transfer was related to isothermal processes; the Cartesian coordinate system was used, and the z-axis was directed vertically upwards. These assumptions made it possible to consider in the model of subsoil moisture movement only the dynamics of capillary forces and sorption occurring due to soil moistening. As the result, a mathematical model of subsoil moisture transfer was proposed on the basis of the Navier-Stokes equation for water movement in a porous medium. This let to determine the main parameters of the moisture transfer dynamics in the layer under consideration: the coefficients of diffusivity, moisture conductivity and capillary absorption capacity. At the same time, a computer program was developed to solve the boundary value problem of dynamics – subsoil moisture transfer on a slope, taking into account the heterogeneous structures obtained during soil treatment using a new method.

Interfacial functionalization and capillary force welding of enhanced silver nanowire-cellulose nanofiber composite electrodes for electroluminescent devices.

Interfacial functionalization and capillary force welding of enhanced silver nanowire-cellulose nanofiber composite electrodes for electroluminescent devices.

Temperature-driven capillary motion of liquid droplets in rough and chemically heterogeneous nanopores

This study investigates how surface roughness and chemical heterogeneity within nanopores can be harnessed to achieve temperature-induced capillary motion of confined liquid droplets. Such temperature-responsive capillary motion has promising applications in nanofluidics, energy storage, environmental engineering, and biomedicine, where precise, dynamic fluid control is essential. To explore this, we consider a model nanopore with two distinct regions: one with a smooth surface and another featuring roughness and chemical heterogeneity. We use a combination of thermodynamic modeling, Grand Canonical Transition Matrix Monte Carlo simulations, and molecular dynamics (MD) simulations. Our aim is to examine how variations in interfacial free energy, entropy, and interfacial fluctuations affect the droplet's motion. The thermodynamic model suggests that nanopores with regions of similar interfacial free energies but different interfacial fluctuations enable temperature-driven motion. Enhanced interfacial entropy in the rougher region, due to stronger solid–liquid interfacial fluctuations, leads to a greater reduction in interfacial free energy with temperature. MD simulations confirm that temperature changes influence droplet position, though interfacial frictional effects between regions pose free energy barriers that restrict full transition. Our findings suggest that, with tailored surface characteristics, it is possible to achieve temperature-driven capillary motion in nanopores, providing a basis for developing adaptable nanoscale fluidic systems. Future research could further explore these dynamics with varied surface designs and fluid types to advance temperature-responsive nanofluidic applications.

Pressure drop study of two-phase flows under condensation within capillary tubes

Pressure drop study of two-phase flows under condensation within capillary tubes

Oscillatory two-phase flow dynamics in capillary tubes under microgravity conditions: Numerical modeling and qualitative analysis of the flow structures

Oscillatory two-phase flow dynamics in capillary tubes under microgravity conditions: Numerical modeling and qualitative analysis of the flow structures

Fluid dynamics of droplet impact and splitting on superhydrophobic wedges

Fluid dynamics of droplet impact and splitting on superhydrophobic wedges