Fluid Components Research Articles

Saliva Crystallization Features in Young People with Different Levels of Physical Activity

The aim of the study was to estimate the features of dehydration structuring of saliva in untrained people. Methods and Results: The study included 35 untrained students (Group 1) and 38 people who regularly exercise (Group 2), who do not have any chronic diseases. The mean age of participants was 17-18 years. The crystallogenic activity and initiatory potential were evaluated for each sample of biological fluid. The crystallization of mixed saliva was studied using the method of classical crystalloscopy, and the initiating properties were studied by the method of comparative tezigraphy. A 0.9% sodium chloride solution was used as the base substance in the tezigraphic test. The conducted crystalloscopic studies have demonstrated significant differences in the crystallogenic and initiating properties of mixed saliva in people who regularly engage in physical training, compared with untrained individuals. They manifest themselves in a significant qualitative and quantitative transformation of the crystalloscopic picture of the biological fluid, including single-crystalline and dendritic components, as well as in the representation of amorphous bodies in micro-preparations of the biological medium. In the tezigraphic test, it was found that the initiatory potential of mixed saliva also undergoes significant shifts. These shifts are realized in the activation of the initiating ability of biological fluid and optimization of textural characteristics of tezigrams (reduction of cellular density and increase in uniformity) in combination with a decrease in the degree of destruction of structural picture elements and a moderate expansion of the marginal zone of micro-preparations.

Technical note: Comparison of forensic swabs for intravaginal sampling

This study compared the currently used swab Prionics ForensiX Evidence Collection Kit with the alternatives Prionics ForensiX Evidence Collection Tube SafeDry and Sarstedt Forensic Swab XL. Volunteers provided intravaginal swabs collected with all swab types at specific time points after unprotected sexual intercourse. Quantifiable DNA, detectability of seminal fluid component (prostate specific antigen, PSA) and spermatozoa were evaluated to find the best-performing swab type.While Sarstedt XL showed significantly higher DNA quantities for sperm cell fractions than ForensiX Kit, the more concise PSA test results clearly favour ForensiX SafeDry. Reassuringly, mostly complete autosomal STR profiles of male components were obtained for sperm cell fractions at all time points and tested swabs. Switching to the higher performing ForensiX SafeDry with improved sampling and processing properties will also benefit victims, medical personnel, and investigators.

SIMULATION OF TERNARY FLUID MIXTURES SEPARATION BY PHASE-FIELD FREE ENERGY LBM

This article reviews the mathematical and computer modeling of the process of ternary fluid mixture separation by free energy based phase flied Lattice Boltzmann method. The process under study is considered in a limited area having the shape of a rectangle. Three different sets of fluid components with different structures are specified. The mathematical model constructed to describe this process is based on the Navier-Stokes equation for an incompressible fluid and the Cahn-Hilliard equation. The numerical model is built on the basis of LBM using the D2Q9 model. Numerical experiments were performed for two scenarios: (1) – investigate the model without gravity, in order to determine the patterns of the surface tension effect and (2) - investigate the model with gravity force. The results obtained determine the adequacy of the constructed model for a three-component fluid.

Water quality and the impact to the health

Water is the major constituent of the human body. Water is essential for life and maintaining optimal levels of hydration is important for humans to function well. Water makes up a large proportion of our body weight, distributed between the intracellular (inside cells) and extracellular (water in the blood and in between cells) compartments. Water is the major component of body fluids, such as blood, synovial fluid (fluid in the joints), saliva and urine, which perform vital functions in the body. Human body cannot produce enough water by metabolism or obtain enough water by food ingestion to fulfil its needs. As a consequence, we need to pay attention to what we drink throughout the day to ensure that we are meeting our daily water needs, as not doing so may have negative health effects.

The Importance of the Respiratory Physical Exam: A Case Report

A 34-year-old male with a history of quadriplegia following a spinal cord injury presented to the clinic endorsing persistent dry cough and mild chest pain for the past three weeks. The patient appeared comfortable, in no acute distress, and with stable vital signs during the visit. His physical exam was unremarkableexcept for no air movement in the right lung. An urgent in-house chest X-ray showed a large pneumothorax with a small layering fluid component and near-complete right lung collapse. The physical exam has been the cornerstone of medical practice since its inception. This tradition has been passed down from physician educators to learners for centuries. Our case is unique because patients with severe pneumothorax usually exhibit urgent symptoms, such as respiratory distress and desaturations at presentation. However, our patient presented with only mild non-specific symptoms and did not have significant risk factors.Therefore, performing a thorough physical exam is essential to help uncover life-threatening pathologies even in patients with no severe symptoms.

Temporal and spatial separation mechanisms of the Cu and Mo mineralization in the Dabate porphyry deposit, Western Tianshan, Xinjiang, China

Dabate deposit is a typical porphyry Cu-Mo deposit in the Western Tianshan, Xinjiang, China. Both the Cu and Mo mineralization are mainly associated with intrusion of rhyolite porphyry. Distinguishing from typical porphyry deposits, the Cu mineralization and Mo mineralization are separated from each other on both the temporal and spatial scales. The Cu orebodies are mainly hosted in the contact zone between the rhyolite porphyry and Tuosiku’ertawu Formation and predominantly occur as fluorite-arsenopyrite-Cu-sulfides ± K-feldspar ± quartz veins (Cu-1 stage), whereas the Mo orebodies are mostly hosted in the inner part of the rhyolite porphyry and are typically presented as Mo-2 stage quartz-molybdenite veins (external Cu and internal Mo). Total homogenization temperatures (Th, L-V) for boiling fluid inclusion assemblage of the Mo-2 stage occurred at 302 to 358 °C, with corresponding salinities of 1.4 to 38.1 wt% NaCleqv. H-O isotope data indicate that the Mo mineralization fluids were mainly derived from magmatic water. The non-boiling fluids of the Cu-1 stage originated from magmatic fluids and meteoric water, which were characterized by high temperature (323 to 379 °C) and low salinity (2.6 to 5.9 wt% NaCleqv) as well as Cu, As, and volatile enrichment. These features are different from the initial magmatic fluids of this deposit, indicating that the Cu mineralization may occur before the Mo mineralization (early Cu and late Mo) and the magmatic fluid components of the Cu-1 stage should be derived from the condensation of the low-salinity vapor generated by boiling of the hydrothermal fluids (351 to 405 °C; 1.8 to 40.1 wt% NaCleqv) for the earliest Mo-1 stage barren quartz veins. The positive δ34S values (5.5 to 9.8‰) of sulfides indicate that the sulfur in the ore-forming fluids was derived from magma and country rocks. The subtle change in fluid conditions from the high temperature (peak range 340 to 360 °C), alkaline, and slightly more oxidized of the Cu-1 stage to high temperature (peak range = 320 to 340 °C), more reduced, and acidic of the Mo-2 stage gave rise to the temporal separation of Cu and Mo mineralization. The Cu, As, and volatiles (e.g., CO2, HF), preferentially partitioned into the vapor phase, were highly enriched in Cu ore-forming fluids, whereas Mo mineralization fluids contained the majority of Mo with strong preference for the brine phase. Therefore, the spatial separation of the Cu and Mo mineralization could be attributed to selectively fractionating between the vapor phase and hypersaline liquid of the Cu and Mo metals during the process of fluid boiling.

Extreme geochemical heterogeneity beneath the North Tonga Arc: Interaction of a subduction zone with intraplate seamount chains

We provide new geochemical and isotope data for lavas from six young submarine volcanoes from the northernmost oceanic Tonga island arc. These lavas have low concentrations of moderately incompatible trace elements, but are enriched in Nb and Ta compared to all other Tonga island arc lavas, and their Nd, Hf and Pb isotope compositions resemble those of rejuvenated lavas from the nearby Samoa hotspot. These unusual compositions indicate that the mantle source of North Tonga lavas was depleted by prior melting events, before re-enrichment by a partial melt enriched in highly incompatible elements with Nd, Hf and Pb isotope compositions similar to Samoan intraplate lavas. Samoa plume mantle is flowing southwards beneath the northern Tonga island arc and Lau Basin, in part guided by rifting of the Tonga plate lithosphere. A fluid component was later added from a mixture of subducted pelagic sediment and subducting Louisville Seamount Chain volcanic material. Our new data show that the Louisville component is only found in lavas from volcanoes occurring along ∼100 km of the arc front, indicating that the oceanic crust loses Pb by dehydration over a relatively small depth interval during subduction. The compositions of lavas from the northern Tonga island arc are therefore influenced by material from two hotspots; southwards inflow of mantle from the active Samoa plume beneath the arc within the past 6 Ma, and a subduction component from >80 Ma old subducted Louisville Seamount Chain basalts.

Urea transporter-B expression on the ocular surface and in the lacrimal glands

ObjectiveUrea is a component of tear fluid showing a significantly decreased concentration in dry eye disease. The urea content of tear fluid may depend on urea transporters. The purpose of this study was to examine the expression of urea transporter B (UT-B) at the ocular surface and in the lacrimal glands. MethodsUT-B protein and mRNA expression was investigated in human, porcine, and murine samples. Immunohistochemical staining for UT-B was performed on paraffin sections of human, porcine, and murine corneas, eyelids, and lacrimal glands (n = 5 each). Reverse transcriptase polymerase chain reaction was conducted to detect UT-B mRNA in human and murine cornea, conjunctiva, Meibomian gland, and lacrimal gland (n = 5 each). ResultsUT-B protein expression was comparable in all three species. It was found in the corneal epithelium and endothelium, in the conjunctival epithelium, in the end pieces and excretory ducts of the lacrimal gland, Meibomian gland, and in the glands of Moll and Zeis. The glands of Zeis and the Meibomian glands showed intense UT-B signals in the basal layers of the alveolar epithelia and in the cells of the ductal epithelia. UT-B mRNA was detected in all samples analyzed. ConclusionUT-B is expressed by the cells and tissues of the ocular surface and in the lacrimal glands. Potential changes in urea transporter expression might have implications for the pathogenesis of dry eye disease. Since comparable results were obtained for all species investigated, the presented findings may open the door for DED-relevant experimentation on porcine and murine model systems.

Preliminary study for the application of Raman spectroscopy for the identification of Leishmania infected dogs.

Raman spectroscopy is a rapid qualitative and quantitative technique that allows the simultaneous determination of several components in biological fluids. This methodology concerns an alternative technique to distinguish between non-healthy and healthy subjects. Leishmaniasis is a zoonosis of world interest, the most important agent is L. infantum. Dogs are the principal reservoirs affected by a broad spectrum of clinical features. During a clinical exam, blood samples were collected in tubes without anticoagulants, from twenty two dogs. One aliquot was used for serological test for Leishmaniasis, one aliquot was subjected to the Raman spectroscopic analysis. Animals were divided into two groups of equal subjects, Leishmania group (LG) constituted by infected dogs, and control group (CG) constituted by healthy dogs. The acquired spectra were different in the region 1200–1370 cm−1, in which it is possible to distinguish the amide III vibration (~ 1300 cm−1). In LG, an evident shift to the shortwave region is observed in spectral frequencies of the band centered at ~ 1250 cm−1. Our results distinguished between LD group and CG. Further studies are necessary to exclude the effect of metabolic modification due to disease on the recorded spectra changes and to consolidate the achievability of Raman spectroscopy as rapid and less expensive diagnosis of Leishmaniasis.

Soret separation and thermo-osmosis in porous media

When a temperature difference is applied over a porous medium soaked with a fluid mixture, two effects may be observed, a component separation (the Ludwig–Soret effect, thermodiffusion) and a pressure difference due to thermo-osmosis. In this work, we have studied both effects using non-equilibrium thermodynamics and molecular dynamics. We have derived expressions for the two characteristic parameters, the Soret coefficient and the thermo-osmotic coefficient in terms of phenomenological transport coefficients, and we show how they are related. Numerical values for these coefficients were obtained for a two-component fluid in a solid matrix where both fluid and solid are Lennard–Jones/spline particles. We found that both effects depend strongly on the porosity of the medium and weakly on the interactions between the fluid components and the matrix. The Soret coefficient depends strongly on whether the fluid is sampled from inside the porous medium or from bulk phases outside, which must be considered in experimental measurements using packed columns. If we use a methane/decane mixture in bulk as an example, our results for the Soret coefficient give that a temperature difference of 10 K will separate the mixture to about 49.5/50.5 and give no pressure difference. In a reservoir with 30% porosity, the separation will be 49.8/50.2, whereas the pressure difference will be about 15 bar. Thermo-osmotic pressures with this order or magnitude have been observed in frost-heave experiments.Graphic abstract

Fully-decoupled, energy stable second-order time-accurate and finite element numerical scheme of the binary immiscible Nematic-Newtonian model

We consider the numerical approximation of a two-phase complex fluid flow model that couples the immiscible liquid crystal fluid component immersed in the ambient free flow field, where the free interface motion between the two fluids is simulated by using the phase-field approach via the energy variational method. The model is a highly nonlinear coupling system, which is composed of the Navier–Stokes equations for the flow field, the Cahn–Hilliard equations for the free moving interface, and the constitutive equation for the nematic liquid crystal. This paper proposes an effective full-discrete finite element numerical scheme to solve the model and makes the scheme not only have the characteristics of linearity, second-order time accuracy, unconditional energy stability, decoupling structure but also only need to solve a few constant-coefficient elliptic equations at each time step. The unconditional energy stability of the scheme and the detailed implementation process are further given. Various numerical experiments including the well-known “beads-on-string” phenomena are also simulated to illustrate the effectiveness of the scheme.

Oil Recovery Dynamics of Natural Gas Huff ‘n’ Puff in Unconventional Oil Reservoirs Considering the Effects of Nanopore Confinement and Its Proportion: A Mechanistic Study

Summary When reservoir fluids are confined by nanoscale pores, pronounced changes in fluid properties and phase behavior will occur. This is particularly significant for the natural gas huff ‘n’ puff (HNP) process as a means of enhanced oil recovery (EOR) technology in unconventional reservoirs. There have been considerable scientific contributions toward exploring the EOR mechanisms, yet almost none considered the effects of nanopore confinement and its proportion on the oil recovery dynamics. To bridge this gap, we developed an approach to calculate fluid phase equilibrium in nanopores by modifying the Rachford-Rice equation and Peng-Robinson equation of state (PR-EOS), completed by considering the shifts of fluid critical properties and oil/gas capillary pressure. Afterward, the effect of nanopore radius (rp) on the phase behavior between the injected natural gas and oil was thoroughly investigated. Compositional simulation was performed using a rigorously calibrated model based on typical properties of a tight reservoir to investigate the production response of natural gas HNP, including the effects of nanopore confinement and its proportion. We demonstrated that the critical pressure and temperature of fluid components decreased with the reduction in rp, especially for heavy constitunts. The saturation pressure, density, and viscosity of the oil in the presence of natural gas all declined linearly with 1/rp in the confined space. The suppression of fluid saturation pressure was indicative of an extended single-phase oil flow period during production. The cumulative oil production was approximately 12% higher if the confinement effect was considered in simulation. Moreover, the average reservoir pressure declined rapidly resulting from this effect, mainly caused by the intensified in-situ gas/oil interaction in nanopores. The results of this paper supplement earlier findings and may advance our understanding of nanopore confinement during natural gas HNP, which are useful for field-scale application of this technique.

Metabolites and Biomarker Compounds of Neurodegenerative Diseases in Cerebrospinal Fluid.

Despite recent advances in diagnostic procedures for neurological disorders, it is still difficult to definitively diagnose some neurodegenerative diseases without neuropathological examination of autopsied brain tissue. As pathological processes in the brain are frequently reflected in the components of cerebrospinal fluid (CSF), CSF samples are sometimes useful for diagnosis. After CSF is secreted from the choroid plexus epithelial cells in the ventricles, some flows in the brain, some is mixed with intracerebral interstitial fluid, and some is excreted through two major drainage pathways, i.e., the intravascular periarterial drainage pathway and the glymphatic system. Accordingly, substances produced by metabolic and pathological processes in the brain may be detectable in CSF. Many papers have reported changes in the concentration of substances in the CSF of patients with metabolic and neurological disorders, some of which can be useful biomarkers of the disorders. In this paper, we show the significance of glucose- and neurotransmitter-related CSF metabolites, considering their transporters in the choroid plexus; summarize the reported candidates of CSF biomarkers for neurodegenerative diseases, including amyloid-β, tau, α-synuclein, microRNAs, and mitochondrial DNA; and evaluate their potential as efficient diagnostic tools.

Experimental study of fracture evolution in enhanced geothermal systems based on fractal theory

Long-term seepage under high temperature and high pressure affects fracture morphology, ultimately impacting the development efficiency of Enhanced Geothermal Systems (EGS). In this study, rock samples with different morphologies were produced and their morphologies were described quantitatively using fractal dimension theory. Experimentally, distilled water and simulated geothermal fluid were injected into fractures at a constant flow rate for 360 h. The behaviors of different fluid components during the fracture evolution process under high temperature and high pressure were observed. Results show that apertures and permeability decreased by 7.1% and 19.5% when distilled water was used, while they decreased by 0.6% and 1.8% respectively when simulated geothermal fluid was injected. The fracture apertures first decreased and then gradually increased. The more complex the fracture shape, the faster the mineral dissolution rate. With fractal dimensions of 1.007, 1.027 and 1.056, the dissolution rates of rock-like minerals in deionized water were 9.43×10−2, 1.33×10−1 and 1.51×10−1 mg/L per 12 hours, respectively. This study lays a foundation for further research on fracture network evolution and provides a basis for the long-term efficient and stable operation of EGS.

A vertex-centered finite volume method with interface sharpening technique for compressible two-phase flows

A robust and efficient finite volume method with interface sharpening technique has been developed to solve the six-equation multi-fluid single-pressure model for compressible two-phase flows. The numerical method is implemented in a three-dimensional vertex-centered code. A least-squares reconstruction with Kuzmin's vertex-based (VB) limiter is implemented for the volume fraction and a set of primitive variables in the presented finite volume framework. In regions where two different fluid components are present within a cell, a sharpening technique based on THINC (Tangent of Hyperbola for Interface Capturing) is adopted to provide a sharp resolution for the transitioning interface. These reconstructed values are then used as the initial data for Riemann problems. The enhanced AUSM+ -up scheme is applied to both liquid and gas flows. The multi-stage Runge-Kutta method is used for time marching. A number of benchmark test cases are presented to assess the performance of the present method. These include: an air-water interface moving at a constant velocity, Ransom's faucet problem, air-water/water-air shock tube problems with high pressure ratios, a shock in air impacting a water column case, an underwater explosion case and an air bubble blast case. In all of these cases, the shock and rarefaction waves are captured accurately, especially with the THINC interface sharpening technique.

Pseudo-potential lattice Boltzmann model for large density and viscosity ratio fluids

The flow of two immiscible fluid components with large density and viscosity ratios is considered. Using the pseudo-potential lattice Boltzmann model with a non-ideal equation of state and a mixture viscosity formulation, we can develop a model that successfully passes a series of benchmark tests, most importantly co-current layered flows, with no discontinuities in the velocity profiles at interfaces. The model is then applied to applications of bubbles rising in denser fluids and shows good quantitative agreement with previous numerical and experimental results. The model is also applied to the flow of two immiscible fluids in a porous medium and shows characteristics that are physically consistent with established experimental observations.

Thermolab: A Thermodynamics Laboratory for Nonlinear Transport Processes in Open Systems

AbstractWe developed a numerical thermodynamics laboratory called “Thermolab” to study the effects of the thermodynamic behavior of nonideal solution models on reactive transport processes in open systems. The equations of the state of internally consistent thermodynamic data sets are implemented in MATLAB functions and form the basis for calculating Gibbs energy. A linear algebraic approach is used in Thermolab to compute Gibbs energy of mixing for multicomponent phases to study the impact of the nonideality of solution models on transport processes. The Gibbs energies are benchmarked with experimental data, phase diagrams, and other thermodynamic software. Constrained Gibbs minimization is exemplified with MATLAB codes and iterative refinement of composition of mixtures may be used to increase precision and accuracy. All needed transport variables such as densities, phase compositions, and chemical potentials are obtained from Gibbs energy of the stable phases after the minimization in Thermolab. We demonstrate the use of precomputed local equilibrium data obtained with Thermolab in reactive transport models. In reactive fluid flow the shape and the velocity of the reaction front vary depending on the nonlinearity of the partitioning of a component in fluid and solid. We argue that nonideality of solution models has to be taken into account and further explored in reactive transport models. Thermolab Gibbs energies can be used in Cahn‐Hilliard models for nonlinear diffusion and phase growth. This presents a transient process toward equilibrium and avoids computational problems arising during precomputing of equilibrium data.

Low-frequency seismic responses during microbial biofilm formation in sands

This study investigates changes in low-frequency attenuation responses of sands during microbial formation of soft viscous biofilms, or extracellular polymeric substances (EPS). The resonant column experiments were conducted with two model bacteria Shewanella oneidensis MR1 and Leuconostoc mesenteroides, while monitoring changes in the wave velocities and damping ratios associated with EPS formation in sands. The results show that the accumulation of soft, viscous EPS hardly changes the wave velocities, both the shear and flexural modes. By contrast, the low-frequency attenuations, both torsional and flexural damping ratios, show significant increases with the accumulation of highly viscous EPS. It is found that the contribution of EPS to seismic responses of water-saturated sands is mainly limited to the pore fluid component, causing additional energy dissipation during wave propagation, but with no or minimal impact on skeletal stiffness or no involvement in seismic stress transfer. With these unique and unprecedented low-frequency seismic data of biofilm-associated sands, the results suggest that the formation and accumulation of soft, viscous EPS or biofilms by bacterial activities can be detected by monitoring seismic attenuation and can also alter the seismic attenuation responses of sands, such as the case under earthquake loading or blast-induced compaction.

Controllable Degradable Plasma Electrolytic Oxidation Coated Mg Alloy for Biomedical Application

A controllable degradable coating on Mg alloy based on plasma electrolytic oxidation (PEO) process is reported for the first time. The reported results show that introduction of silica nanoparticles into PEO electrolytes leads to their reactive incorporation in coatings and thus influencing the degradation behavior. Dissolution of amorphous phases facilitates chemical reaction with components of simulated body fluid, resulting in self-healing effect via redeposition of insoluble conversion products. The dynamic balance between dissolution of the original coating and reconstruction of corrosion layer is mainly determined by the phase composition of the coating as well as the surrounding corrosive medium.

Changes in intracapsular fluid nutritional composition during the early development of the marine gastropod Hemifusus tuba Gmelin

The composition and function of intracapsular biochemical substances are intrinsically correlated; thus, it is important to quantify intracapsular nutritional composition, including protein, glycogen and lipid content, which are required for embryonic development. To explore the intracapsular fluid nutritional composition of the marine gastropod Hemifusus tuba Gmelin during early developmental stages, the embryonic development was divided into seven stages: fertilized egg, cleavage, morula, blastula, gastrula, veliger and juvenile. Results showed that the amino acids contents ranged from 44.98 to 71.52/100 g. Furthermore, 13 amino acids were identified, including five essential amino acids and eight non-essential amino acids. The contents of aspartic acid, proline, and valine were higher, while the contents of the other ten amino acids were relatively lower. Notably, aspartic acid and proline content varied across embryonic development. In addition, saturated fatty acids (SFAs) were dominant fatty acid components in the intracapsular fluid, in which C18:0 was the main fatty acid. Monounsaturated fatty acids (MUFA) primarily comprised C20:1(n − 9), accounting for 30% of the total fatty acids. At the same time, the content of C18:2(n − 6) decreased significantly from the fertilized egg to the blastula stage (p < 0.05). The content of C20:4(n − 6) from fertilized egg to gastrula stage was significantly reduced (p < 0.05). C22:6(n − 3) was significantly lower in the gastrula than in other stages (p < 0.05). Overall, this study provides new information on the intracapsular fluid nutritional composition of H. tuba, helping enrich the biological knowledge of the early developmental stages of marine gastropods.