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Simple Summary: Blood clots are formed when blood vessels are injured. They help stop bleeding and heal wounds, but can also cause serious problems if they block blood flow or break off and travel to other organs. This study investigates how blood clots differ in people with cancer compared to healthy or non-cancerous individuals. This study found that cancer patients have higher levels of histones in their blood, which make their clots stiffer and resistant to lysis. Further, clots formed in cancer patients have higher viscoelastic properties, and hence are harder to break down. These findings suggest that cancer patients have abnormal clotting properties that may increase their risk of developing thrombosis, and evaluating these properties can be helpful in detecting cancer. Background: Blood viscoelasticity and plasma protein levels can play an important role in the diagnosis and prognosis of cancer. However, the role of histones and DNA in modulating blood clot properties remains to be investigated. This study investigates the differences in blood viscoelasticity and plasma protein levels among cancer patients, individuals with other diseases, and healthy individuals. Methods: Blood samples were collected from 101 participants, including 45 cancer patients, 22 healthy individuals, and 34 individuals with other diseases. Rheological properties of clots formed in vitro by reconstituted elements of fibrinogen or plasma were analyzed with an Anton Paar Rheometer, USA. Plasma protein levels of D-dimer, TPA, EPCR, fibrinogen, and histone H3 were measured through ELISA. Blood clots were formed with or without DNA and histones (H3) by adding thrombin and calcium to plasma samples, and were evaluated for viscoelasticity, permeability, and degradation. Results: Cancer patients show higher blood viscoelasticity and plasma D-dimer levels compared to healthy individuals and individuals with other diseases. Our in vitro analysis showed that the addition of histone to the plasma results in a significant decrease in viscoelasticity and mean fiber thickness of the clot formed thereafter. In parallel studies, using plasma from patients, DNA and histones were detected in fibrin clots and were associated with less degradation by t-PA. Moreover, our results show that the presence of DNA and histones not only increases clots' permeability, but also makes them more prone to degradation. Conclusions: Plasma histones and DNA affect the structure of the clot formed and induce defective fibrinolysis. Moreover, the increased viscoelastic properties of plasma from cancer patients can be used as potential biomarkers in cancer prognosis. [ABSTRACT FROM AUTHOR]

Physical properties of blood plasma, such as viscosity, serve as crucial indicators of disease. The inherent capillary effect of paper microchannels, coupled with minimal sample requirement, stimulated the advancement of paper-based viscometers. This study presents a precise, non-contact optoelectronic system using a microfluidic platform for the measurement of blood plasma viscosity. Microchannels were defined onto the filter paper using an available and inexpensive wax crayon, without the need for conventional wax printing equipment. The time required for the 5 μL sample to pass a specific distance was measured using two pairs of infrared sensors. Subsequently, this data was sent to the microcontroller, which automatically calculated the viscosity. Throughout the measurements, sample temperature was maintained at a constant 37 °C through an integrated heater with automated control. The microfluidic platform successfully processed real samples, yielding viscosity measurements in under three minutes. Evaluation with fetal bovine serum, spiked with varying protein concentrations in both native and denatured states, demonstrated a precision exceeding 96% compared to conventional Ostwald viscometer readings. For human subjects exhibiting pathologies affecting serum and plasma viscosity compared to physiological norms, strong correlations were observed between resultant values and clinical diagnoses. The proposed device aims to replace expensive and complex optical equipment, offering a safer alternative for measuring plasma viscosity. Unlike similar devices, it eliminates the risk of component deformation due to chemical contact or unsafe irradiation. [ABSTRACT FROM AUTHOR]

Lipid droplets are important organelles in eukaryotic cells and play an integral role in cellular metabolism. Abnormal changes in intracellular lipid droplets are usually associated with the occurrence of many diseases. Studying the changes in lipid droplet status in cells is of great significance for understanding the regulatory mechanism of intracellular lipid metabolism and the pathogenesis of some related diseases. This paper reports a novel lipid droplet fluorescent probe, LDCN. The D–A–D structure of the probe LDCN brings a good TICT effect, which makes the probe have excellent polarity and viscosity sensitivity. In addition, LDCN has excellent selectivity, good pH stability, and a large Stokes shift (114 nm). LDCN showed good co-localization with commercial lipid droplet dyes in both HeLa cells and tobacco seedling leaf cells. The results showed that the probe was able to selectively sense lipid droplets in living cells. Meanwhile, LDCN could also be used for freshness detection of juice drinks. [ABSTRACT FROM AUTHOR]

The document titled "Contents list" is from the journal Lab on a Chip, which focuses on devices and applications at the micro- and nanoscale. The document provides a list of papers and critical reviews featured in the journal's latest issue. Topics covered include advances and challenges in modeling biological barriers, surface acoustic wave digital microfluidics, developing vasculature within chicken chorioallantoic membrane, parathyroid hormone secretion, human neuron microcircuits, detection of SARS-CoV-2, reconstitution of high-density lipoprotein-mimicking nanoparticles, prostate-specific antigen detection, drug delivery bioelectronics, and point-of-care blood plasma viscosity measurement. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

The greater the viscosity of the blood, the more difficult its flow becomes, leading to an increased incidence of diseases caused by blood circulation disorders. These diseases are commonly associated with the cardiovascular and cerebrovascular systems.High blood viscosity is a primary cause of circulatory system diseases. Studies have shown that accurately measuring blood viscosity and applying this data in clinical trials can help prevent circulatory system diseases.Viscosity data can vary depending on the measurement methods used, even when these methods are based on hydrodynamic principles. Despite using approved blood viscometers, the results often differ depending on the type of viscometer used, potentially causing confusion within the medical field. Informing the medical community about these differences and the level of error associated with each measurement method can help reduce this confusion.To our knowledge, the degree of difference in viscosity measurement results due to different measurement methods and the reasons for these differences have not yet been thoroughly explored. In this study, we selected three blood viscosity measurement methods registered with the Ministry of Food and Drug Safety of Korea to analyze the same canine blood. The viscosity measurements were carried out using each device and compared. The parallel plate and scanning capillary methods yielded similar viscosity values, while the cone plate method showed lower viscosity values.The viscosity of blood, as measured by the three viscometers, differed, indicating that more experimental data must be accumulated to evaluate the cause of these differences. In this paper, we identified several causes of inconsistency and suggested measures to avoid this confusion. However, confirming that the test results show systematic differences is expected to assist clinicians who diagnose and prescribe treatments based on blood viscosity results. The findings of this comparative study are anticipated to serve as a starting point for establishing guidelines or standards for blood viscosity measurement methods. [ABSTRACT FROM AUTHOR]

In this paper, we have provided a mathematical analysis of an empirical result, namely, the Fahraeus–Lindqvist effect, a phenomenon that occurs in capillary tubes with a diameter lower than 0.3 mm. According to this effect, in capillary tubes under 0.3 mm in diameter, the apparent viscosity of blood decreases as the diameter of the tube decreases, making flow possible in these vessels. A two-phase blood flow mathematical model for human capillaries has been presented here. According to Haynes' theory, blood is separated into two layers when it flows from the capillary. It is assumed that the first layer is plasma, and the second layer is the core layer. The plasma layer flows near the wall of the capillary, and the core layer flows along the axis of the capillary. Further, the core layer is assumed to be a mixture of two phases: one is the plasma, and the other is that of RBCs. For mathematical modeling purposes, a curvilinear coordinate system has been adopted, with physical quantities used in tensorial form. Derived equations are solved to find the effective viscosity, which depends upon the radius of the capillary; that is, it reduces viscosity to make blood flow possible. A comparative study was conducted with the experimental result of this effect, and it was observed that the proposed two-phase blood flow model is much closer to the experimental data than the single-phase blood flow model, and both have the same trends. After validation of the model with the experimental result, this model was applied to human capillaries (diameter lower than 10 μ m ) to show the F-L effect, and the impact of various physiological quantities that are relevant to the flow of blood into human capillaries are also discussed here. The impact of hematocrit on various parameters has been demonstrated explicitly. [ABSTRACT FROM AUTHOR]

Recently, aortic valve stenosis has received more attention, and its pathophysiology may be connected to persistent inflammation caused by micro-organisms. This paper investigates the transient electroosmotic hybrid nanofluid (blood model) flow in the annular region between the axially symmetric mild stenosis and the catheter tube. The non-Newtonian Sutterby fluid has been considered as a blood model due to the migration of gyrotactic micro-organisms in the bloodstream. The hybrid nanofluid consists of the suspension of the solid nanoparticles of the (Ag–Al 2 O 3 ) in pure human blood. The problem is simplified using the mild stenosis procedure and solved numerically utilizing the finite difference technique. It is observed that more effort is required to pump the blood in the case of the suspended hybrid nanoparticles than with suspended nanoparticles. Moreover, the results demonstrate that hybrid nanoparticles have better thermal properties than nanoparticles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Evaluation of a near-infrared set-up for the prediction of the hematocrit. • Successful validation with excellent accuracy and precision results. • Robustness experiments were performed to ensure the applicability in clinical practice. • Application on capillary DBS samples obtained via finger prick was included. Dried blood spot (DBS) microsampling has gained interest in different clinical fields, owing to its many advantages compared to conventional blood sampling. However, whilst being applied for decades for screening purposes, some challenges, such as the hematocrit (Hct) effect, hinder further widespread use of DBS for quantitative purposes in clinical practice. Amongst the approaches that were developed to cope with this issue, is the Hct prediction of DBS using near-infrared (NIR) spectroscopy. Using left-over EDTA-anticoagulated patient samples, the accuracy and precision, stability, and robustness were assessed. Furthermore, applicability of the method on capillary DBS was evaluated via finger prick samples. A maximal bias, respectively CV, of 0.012 L/L and 4.5% were obtained. The method was robust towards several aspects, including storage (except for storage at 60°C), measurement location, type of filter paper and spotted volume. Furthermore, the potential to predict the Hct of capillary DBS was demonstrated. A commercially available NIR set-up was extensively and successfully validated, allowing non-contact Hct prediction of DBS with excellent accuracy and precision. This allows to correct for the Hct-based bias observed in partial-punch DBS analysis and the set-up of blood-plasma conversion factors, increasing the application potential of patient-centric sampling. [ABSTRACT FROM AUTHOR]

In this paper, we study the blood flow through blood vessels of various radii (including the case of variable cross section as well as modeling the blood flow through venae and arteries). Two approaches are discussed in order to mimic the dependence of blood viscosity on red blood cells aggregation, which changes with the shear rate and position inside the vessel: Two microstructural parameters together with empirical constitutive equations as a characteristic of aggregation are proposed, namely the microinertia as well as the volume fraction of blood particles (erythrocytes, platelets and leukocytes). Consequently, the Navier–Stokes system of equations for an incompressible fluid is supplemented by a constitutive equation for the moment of inertia in one case and for the volume fraction in another. The problems are solved numerically by the finite volume method for vessels of various geometries in spatial description. A comparison with experimental data for a narrow capillary shows the efficiency of the proposed constitutive equations for describing blood flow. Also, velocity profiles are obtained on the basis of compiled empirical formula for various sections of a blood vessel of variable radius. In addition, the flow through vessels of the human circulatory system, such as the inferior vena cava and the carotid artery, are studied. [ABSTRACT FROM AUTHOR]

This paper discusses the fully developed electromagnetic hydrodynamic flow and heat transfer of a Casson nanofluid Fe3O4-blood in a porous medium. The flow takes place in a horizontal channel with walls at different temperatures. The channel is influenced by an externally applied magnetic field that is perpendicular to the walls of the channel and an externally applied electric field that is perpendicular to the longitudinal vertical plane of the channel. Both of these fields are homogeneous. The induced magnetic field is considered weak and can be neglected. The described problem is represented by differential equations which are analytically solved after the transformation into a dimensionless form. The obtained velocity and temperature distributions of the Casson fluid Fe3O4- blood are graphically represented and the influences of the Hartmann number, the Brinkman number, the power factor, the porosity factor, and the volume fraction of nanoparticles are examined. The Nusselt number and dimensionless friction voltages are given in a table. [ABSTRACT FROM AUTHOR]

The importance of the blood flow feature on the hemorrhage of the cerebral aneurysm is confirmed by surgeons and scientists. In this paper, the effects of blood hemodynamics on the growth and rupture of the Internal Carotid Intracranial (ICA) are fully investigated. This study tries to demonstrate the blood feature inside the ICA at different time stages. Besides, the effect of coiling on blood characteristics is extensively studied in this research. Computational Fluid dynamic (CFD) is used for the analysis of the blood hemodynamics on the wall shear stress and pressure distribution within the aneurysm. Obtained results indicate that reducing the coiling porosity from 0.89 to 0.79 declines maximum WSS by about 26% and 61% for HCT = 0. 3 5 and 0.45, respectively, at the peak systolic stage. Our findings show that decreasing the porosity (or increasing coiling fraction) would decrease the maximum OSI by more than 55% in high blood viscosity of HCT = 0. 4 5. [ABSTRACT FROM AUTHOR]

Diagnostic investigations of aneurysm, hemorrhagic stroke, and other asymptomatic cardiovascular diseases and neurological disorders due to the flow choking (biofluid/boundary layer blockage persuaded flow choking) phenomenon in the circulatory system of humans and animals on the Earth and in the human spaceflight are active research topics of topical interest {Kumar et al., "boundary layer blockage persuaded flow choking leads to hemorrhagic stroke and other neurological disorders in earth and human spaceflight," Paper presented at the Basic Cardiovascular Sciences Conference, 23–25 August 2021 (American Stroke Association, 2021) [Circ. Res. 129, AP422 (2021)] and "Lopsided blood-thinning drug increases the risk of internal flow choking and shock wave generation causing asymptomatic stroke," in International Stroke Conference, 19–20 March 2021 (American Stroke Association, 2021) [Stroke 52, AP804 (2021)]}. The theoretical concept of flow choking [Kumar et al., "Lopsided blood-thinning drug increases the risk of internal flow choking leading to shock wave generation causing asymptomatic cardiovascular disease," Global Challenges 5, 2000076 (2021); "Discovery of nanoscale boundary layer blockage persuaded flow choking in cardiovascular system—Exact prediction of the 3D boundary-layer-blockage factor in nanotubes," Sci. Rep. 11, 15429 (2021); and "The theoretical prediction of the boundary layer blockage and external flow choking at moving aircraft in ground effects," Phys. Fluids 33(3), 036108 (2021)] in the cardiovascular system (CVS) due to gas embolism is established herein through analytical, in vitro (Kumar et al., "Nanoscale flow choking and spaceflight effects on cardiovascular risk of astronauts—A new perspective," AIAA Paper No. 2021-0357, 2021), in silico (Kumar et al., "Boundary layer blockage, Venturi effect and cavitation causing aerodynamic choking and shock waves in human artery leading to hemorrhage and massive heart attack—A new perspective," AIAA Paper No. 2018-3962, 2018), and in vivo animal methodology [Jayaraman et al., "Animal in vivo: The proof of flow choking and bulging of the downstream region of the stenosis artery due to air embolism," Paper presented at the Basic Cardiovascular Sciences Conference, 25–28 July 2022 (American Heart Association, 2022)]. The boundary layer blockage persuaded flow choking phenomenon is a compressible viscous flow effect, and it arises at a critical pressure ratio in continuum/non-continuum real-world yocto to yotta scale flow systems and beyond [Kumar et al., "Universal benchmark data of the three-dimensional boundary layer blockage and average friction coefficient for in silico code verification," Phys. Fluids 34(4), 041301 (2022)]. The closed-form analytical models, capable of predicting the flow choking in CVS, developed from the well-established compressible viscous flow theory are reviewed and presented herein. The lower-critical flow-choking index of the healthy subject (human being/animal) is predicted through the speciation analysis of blood. The upper-critical flow-choking index is predicted from the specific heat of blood at constant pressure (Cp) and constant volume (Cv), estimated using the Differential Scanning Calorimeter. These flow-choking indexes, highlighted in terms of systolic-to-diastolic blood pressure ratio (SBP/DBP), are exclusively controlled by the biofluid/blood heat capacity ratio (BHCR = Cp/Cv). An in vitro study shows that nitrogen (N2), oxygen (O2), and carbon dioxide (CO2) gases are predominant in fresh-blood samples of the healthy humans and Guinea pigs at a temperature range of 37–40 °C (98.6–104 °F) causing gas embolism. In silico results demonstrated the existence of the biofluid/boundary layer blockage persuaded flow choking, stream tube flow choking, shock wave generation, and pressure overshoot in the downstream region of simulated arteries (with and without stenosis), at a critical pressure ratio, due to gas embolism. The flow choking followed by aneurysm (i.e., bulging of the downstream region of the stenosis artery due to shock wave generation) due to air embolism is demonstrated through small animal in vivo studies. We could corroborate herein, with the animal in vivo and three-dimensional in silico studies, that flow-choking followed by shock wave generation and pressure overshoot occurs in arteries with stenosis due to air embolism at a critical pressure ratio. Analytical models reveal that flow-choking occurs at relatively high and low blood viscosities in CVS at a critical blood pressure ratio (BPR), which leads to memory effect (stroke history/arterial stiffness) and asymptomatic cardiovascular diseases [Kumar et al., "Lopsided blood-thinning drug increases the risk of internal flow choking leading to shock wave generation causing asymptomatic cardiovascular disease," Global Challenges 5, 2000076 (2021)]. We concluded that an overdose of drug for reducing the blood viscosity enhances the risk of flow choking (biofluid/boundary layer blockage persuaded flow choking) due to an enhanced boundary layer blockage (BLB) factor because of the rise in Reynolds number (Re) and turbulence. An analytical model establishes that an increase in Re due to the individual or the joint effects of fluid density, fluid viscosity, fluid velocity, and the hydraulic diameter of the vessel creates high turbulence level in CVS instigating an escalated BLB factor heading to a rapid adverse flow choking. Therefore, prescribing the exact blood-thinning course of therapy is crucial for achieving the anticipated curative value and further annulling adverse flow choking (biofluid/boundary layer blockage persuaded flow choking) in CVS. We could conclude authoritatively herein, with the animal in vivo studies, that flow choking occurs in the artery with stenosis due to air embolism at a critical BPR (i.e., SBP/DBP = 1.892 9), which is regulated by the heat capacity ratio of air. The cardiovascular risk due to boundary layer blockage persuaded flow choking could be diminished by concurrently reducing the viscosity of biofluid/blood and flow-turbulence. This comprehensive review is a pointer toward achieving relentless unchoked flow conditions (i.e., flow Mach number < 1) in the CVS for prohibiting asymptomatic cardiovascular diseases and neurological disorders associated with flow choking and shock wave generation followed by pressure overshoot causing arterial stiffness. The unchoked flow condition can be achieved in every subject (human/animal) by suitably increasing the thermal-tolerance-level in terms of BHCR and/or by reducing the BPR within the pathophysiological range of individual subjects through the new drug discovery, the new companion drug with the conventional blood thinners and/or proper health care management for increasing the healthy-life span of one and all in the universe. [ABSTRACT FROM AUTHOR]

Blood viscosity is the defining health indicator for hyperviscosity syndrome patients. This paper introduces an alternative approach for the real-time monitoring of blood viscosity by employing a surface-horizontal surface acoustic wave (SH-SAW) device at room temperature. A novel bi-layer waveguide is constructed on top of the SAW device. This device enables the SAW sensing of liquid droplets utilizing a bi-layer waveguide, consisting of a zinc oxide (ZnO) enhancement layer and Parlyene C, that facilitates the promotion of the surface horizontal mode. The ZnO piezoelectric thin-film layer enhanced the local particle displacement and dielectric coupling while the Parylene C layer constrained the wave mode at the interface of the piezoelectric material and polymer material. The device was tested with a liquid drop on the SAW delay-line path. Both experimental and finite element analysis results demonstrated the benefits of the bi-layer waveguide. The simulation results confirmed that the displacement field of local particles increased 9 times from 1.261 nm to 11.353 nm with the Parylene C/ZnO bi-layer waveguide structure. The device demonstrated a sensitivity of 3.57 ± 0.3125 kHz shift per centipoise enabling the potential for high precision blood viscosity monitoring. [ABSTRACT FROM AUTHOR]

In this paper, the tools of dynamical systems theory are applied to examine the streamline patterns and their local and global bifurcations for ciliary-induced peristalsis of non-Newtonian fluid (blood) with the suspension of hybrid nanoparticles (Cu–Ag/Phan–Thien–Tanner based fluid) in a tube with heat source effect. The thermodynamics of this model are recently described by Ali et al. (Biomech Model Mechanobiol 20:2393–2412, 2021), where the fluid flows through a tube whose inner walls are considered to be ciliated with small hair-like structures. However, our novel approach allows us to create a complete picture of the model's overall dynamic behavior in terms of bifurcation point analysis exhibiting qualitatively different flow modes. Special attention is paid to the computing, analysis and simulation of equilibrium points in terms of capturing the global dynamics, such as evaluating the heteroclinic bifurcation, which is used to identify trapping phenomena in response to biological characteristics such as wave amplitude, Weissenberg and wave numbers. The main novelty here is the ability to control the position of the equilibrium points in the domain of interest, allowing one to identify global bifurcations that reflect key dynamic properties of the model. Based on the advantages of this technique, the maximum trapping volume and symmetric trapping zones adjacent to the walls are determined as a novel result. We also show that as the solid volume fraction of copper and the Brinkman number increases, the isotherm patterns become more distorted. Our findings highlight a novel class of complex behavior that governs transitions between qualitatively different modes and trapping phenomena. [ABSTRACT FROM AUTHOR]

This paper presents a continuum approach for the blood flow simulation, inside the micro-channel of the few micrometers characteristics dimension, within the context of the finite volume method on unstructured grids. The velocity and pressure fields, for the blood flow, are obtained here by solving the Navier–Stokes equations. A particle transport equation, based on the diffusive flux model, provides the hematocrit distribution (i.e., the red blood cells volume-fraction). The momentum conservation equation for a non-Newtonian fluid model is coupled with the particle transport equation through the constitutive blood viscosity model, and this blood viscosity is dependent on hematocrit and shear rate. The continuum approach for blood flow inside the micro-channel of the length scale of a few micrometers to a few hundred micrometers is expected to break down. Interestingly, the present approach provides meaningful insights into biophysics with less computational cost and shows a good match with the experiments and mesoscale simulation with a maximum average deviation of 11% even at the characteristic dimensions of 10–300 μm. A correlation is proposed for additional-local shear rate in terms of the hematocrit and the ratio of red blood cells diameter to the channel diameter, which helps us to demonstrate an increase in the accuracy and also eliminates the issues of unphysical hematocrit reported in the earlier studies available in the literature. The study is extended to provide new results inside a square and rectangular cross section micro-channels, under a range of inlet parameters. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the microstructure of high-viscosity modified asphalt binder (HVA) containing high-content polymers and its effect on fatigue performance, as well as the applicability of different analytical methods and failure criteria of linear amplitude sweep (LAS) test to HVA. In this paper, two types of HVAs with different polymer contents, a commercial HVA, a conventional polymer-modified asphalt binder, and a base asphalt binder were first prepared or selected. Fluorescence microscopy tests, time sweep tests, and LAS fatigue tests were then performed on these binders. Finally, the fatigue properties of the different binders were analyzed in depth using different analytical methods and failure criteria. The results show that the polymers in HVA crosslink with each other to form a strong cross-linking structure, and the phase inversion of the polymers renders them into a continuous phase, which significantly improves the fatigue damage resistance of the HVA; moreover, the evolutions of stress with shear strain for the fatigue process of HVAs is related to the polymer network. Besides, the two-dimensional damage characteristic curve (DCC) cannot accurately reflect the evolution of the fatigue performance of HVA, and this paper suggests the use of a three-dimensional DCC curve with strain information. Furthermore, the 35% reduction in C 0 in the dissipative energy method is not a suitable failure criterion, a more accurate fatigue performance ranking can be obtained by using the yield stress as the failure criterion. Although the fatigue resistance of HVA after yield stress is theoretically considered using the pseudo-strain energy approach, HVA does not show a peak of stored pseudo-strain energy even when the strain is increased to 60% in the LAS test. Therefore, the maximum strain value (30%) in the standard LAS test is not sufficient in characterizing high-polymer HVAs because there is not enough fatigue accumulation of HVAs in this range, consequently, the maximum shear strain parameter in the LAS experiment needs to be reconsidered. • Polymer morphology and its crosslinking networks in HVA with high-content polymers were analyzed. • The fatigue properties of HVAs based on LAS test and different analytical methods are compared. • The fatigue crack length and its evolution of HVA are characterized. • The deficiencies of the LAS test to evaluate the fatigue resistance of HVA and suggestions for modifications are presented. [ABSTRACT FROM AUTHOR]

Platelet–endothelial interactions have a critical role in microcirculatory function, which maintains tissue homeostasis. The subtle equilibrium between platelets and the vessel wall is disturbed by the coronavirus disease 2019 (COVID-19), which affects all three components of Virchow's triad (endothelial injury, stasis and a hypercoagulable state). Endotheliitis, vasculitis, glycocalyx degradation, alterations in blood flow and viscosity, neutrophil extracellular trap formation and microparticle shedding are only few pathomechanisms contributing to endothelial damage and microthrombosis resulting in capillary plugging and tissue ischemia. In the following opinion paper, we discuss major pathological processes leading to microvascular endothelial activation and thrombosis formation as a possible major adverse factor driving the deterioration of patient disease course in severe COVID-19. [ABSTRACT FROM AUTHOR]

Following recent works on the sonochemical degradation of butyl ethyl piperidinium bis-(trifluoromethylsulfonyl)imide ([BEPip][NTf2]), monitoring of sonoluminescence (SL) spectra in the first tens of seconds of sonolysis was needed to better characterize the formed plasma and to question the correlation of the SL spectra with the viscosity. A very dry [BEPip][NTf2] ionic liquid (IL) and a water-saturated liquid are studied in this paper. In both cases, IL degradation is observed as soon as SL emission appears. It is confirmed that the initial evolution of the SL intensity is closely linked to the liquid viscosity that impacts the number of bubbles; however, other parameters can also play a role, such as the presence of water. The water-saturated IL shows more intense SL and faster degradation. In addition to the expected bands, new emission bands are detected and attributed to the S2 B-X emission, which is favored in the water-saturated ionic liquid. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two organic fluorescent dyes DCM-1 and DCM-2 with near-infrared fluorescence were designed and synthesized. • DCM-1 and DCM-2 have a specific fluorescence response to viscosity. • DCM-1 and DCM-2 can be successfully applied to the imaging of dynamic changes in viscosity in living cells. The development of near-infrared organic fluorescent dyes with tunable emission profiles is highly required in the field of biological sensing and imaging. In this paper, we designed and synthesized two organic fluorescent dyes, DCM-1 and DCM-2, through the hybridization of indolizine and dicyanomethylene-4H-pyran skeleton. These two compounds show near-infrared fluorescence with emission maximum approximately at 640 and 680 nm, respectively. Notably, both DCM-1 and DCM-2 have specific responses to viscosity without being interfered by biological relevant species. Cell experiments demonstrate that DCM-1 and DCM-2 can detect dynamic changes in viscosity within living cells, suggesting their potential applications in chemical biology research. [ABSTRACT FROM AUTHOR]

This paper introduces a wireless pump that uses magnetic wireless manipulation to pump blood in the legs. A compact size and sufficient hydrodynamic performance were the most important requirements. Because the bonded magnet technique allows for a complex shape and various magnetization orientations, we fabricated a magnetic impeller from magnetic SmFeN powder. The impellers demonstrated a magnetic moment of 2772.64 emu and coercive force of 7.55 kOe. Using the impeller, we developed a tiny blood pump with a diameter of 22mm and height of 6mm. The pump allows for a maximum flow rate of 2.7 l/min and maximum pump head of approximately 170mm Hg at a rotating speed of 6000 rpm. This level of hydrodynamic performance is sufficient to circulate blood in the legs. In this paper, we present the magnetic properties of the magnetic impeller and the hydrodynamic performance with wireless operation. [ABSTRACT FROM AUTHOR]

The theoretical discoveries of the Sanal flow choking [V. R. Sanal Kumar et al., "Sanal flow choking: A paradigm shift in computational fluid dynamics code verification and diagnosing detonation and hemorrhage in real‐world fluid‐flow systems," Global Challenges 4, 2000012 (2020)] and streamtube flow choking [V. R. Sanal Kumar et al., "Deflagration to detonation transition in chemical rockets with sudden expansion/divergence regions," AIAA Paper No. 2020-3520, 2020] achieved significant contemplation in all branches of science and engineering for resolving various unanswered scientific questions brought onward from the beginning of this era [V. R. Sanal Kumar et al., "A closed-form analytical model for predicting 3D boundary layer displacement thickness for the validation of viscous flow solvers," AIP Adv. 8, 025315 (2018)]. The applications of these flow choking phenomena are more significant in aerospace industries [V. R. Sanal Kumar et al., "Nanoscale flow choking and spaceflight effects on cardiovascular risk of astronauts—A new perspective," AIAA Paper No. 2021-0357, 2021] and medical sciences [V. R. Sanal Kumar et al., "Lopsided blood-thinning drug increases the risk of internal flow choking leading to shock wave generation causing asymptomatic cardiovascular disease," Global Challenges 2021, 2000076]. Herein, as an offshoot of the Sanal flow choking phenomena, the proof of the concept of boundary-layer-blockage (BLB) persuaded external-flow-choking (EFC) at aircraft-in-ground (AIG)-effect is presented. When the aircraft's ground clearance is relatively low, the evolving BLB factor from both planes (the bottom surface of the aircraft and the ground) creates a transient fluid-throat, leading to the Sanal flow choking and supersonic flow development in the duct flow region. In this physical situation, the pressure ratio (Ptotal/Pstatic) at the external flow choking region is exclusively a function of the specific heat ratio of the fluid. The EFC is more prone for the low wing aircraft flying in the near vicinity to the ground and/or sea with relatively high subsonic Mach number and low angle of attack. At this flying condition, the underside of the aircraft (fuselage and/or wing) and the ground creates the convergent-divergent duct flow effect leading to the EFC at the critical total-to-static pressure ratio. The accurate estimation of the BLB factor at the location of the EFC at AIG effect is presented in this manuscript as a universal yardstick for two-dimensional (2D) in silico simulation. For establishing the proof of the concept of external flow choking and supersonic flow development and shock wave generation, the 2D in silico results are presented for both stationary and moving airfoils in ground effect. In silico results show that the airfoil at stationary position exhibits relatively higher BLB factor and an immediate occurrence of the EFC than the same airfoil moving with the identical inflow Mach number and Reynolds number. We could establish herein that the moving vehicle simulation is inevitable for capturing actual flow physics and further precise examination of the BLB factor and the possibilities of the occurrence of the EFC for credible trajectory optimization of high-speed ground-effect vehicles. [ABSTRACT FROM AUTHOR]

The paper proposes the calculation technique for the coronary blood flow in stenotic arteries with respect to the blood viscosity affecting the parameters of the fractional flow reserve based on the data analysis of the multispectral computed tomography. The calculation technique is also based on regulations that determine the hemodynamics in stenotic vessels. The mathematical simulation is presented for the blood flow in a stenotic coronary artery. This simulation is based on the Navier–Stokes equations. The calculations are carried out using Comsol Multiphysics 4.2. software. The obtained results show that the distribution of the blood flow rate in the stenotic artery is not uniform, and the pressure out of the stenotic segment of the artery depends on the blood viscosity. This must be taken into consideration both in mathematical simulation and invasive coronary angiography of the fractional flow reserve. The research results can be used in effective diagnostics of coronary artery disease. [ABSTRACT FROM AUTHOR]

Blood flow in a double aneurysmatic artery of the normal tissue is studied. A Finite element method is used to analyze numerical simulation of blood flow through aneurysmatic arteries and Comsol multiphysics software is used for blood flow simulation. The Newtonian, generalized Newtonian, Oldroyd-B, and generalized Oldroyd-B models are considered due to the behavior of blood viscosity. In this paper, the effect of aneurysmatic artery on blood flow with permeability in human organs has been investigated. The non-Newtonian models have been applied to study the blood velocity, pressure, and wall shear stress in an aneurysmatic artery. A set of partial differential equations are transformed into dimensionless equations using non-dimensional variables and solved numerically. The novelty of this work is to identify the cardiovascular diseases in case of double aneurysmatic artery conditions for all models. The effect of wall shear stress is a vital factor to determine fatal arterial diseases which may be reported in the research center. The findings of this study can be used to know the atherosclerosis diseases and increase the understanding level of the double aneurysmal artery with the presence of permeability for which may help to enhance the knowledge of medical science. We have focused our consideration on the simulation of blood velocity and pressure in terms of blood flow rate for various Weissenberg numbers (Wi) and Peclet numbers (Pe). In this study, significant changes in blood velocity, pressure, and wall shear stress for all cases due to the presence of permeability at aneurysm in the artery are found. The effect of the Peclet number and Weissenberg number have played a key role in the blood flow at the porous area. The important effects on blood flow of aneurysmatic artery for blood velocity, pressure, and wall stress profiles are presented graphically for Newtonian and non-Newtonian models. [ABSTRACT FROM AUTHOR]

Backgrounds. Chuanxiong Chatiao san (CXCT) is a famous Chinese classical prescription. It has a favorable effect in treating migraine. It is reported that CXCT combined with Western conventional medicine (WCM) could increase the therapeutic efficacy on migraine. The purpose of this paper is to systematically assess the clinical efficacy, safety, and some indexes of CXCT for migraine. Methods. PubMed, Embase Database, China National Knowledge Infrastructure (CNKI), Wanfang Database, the Cochrane Library, and the CBM were searched from January 2000 to February 2019. We made a detailed record of outcome measurements. Meta-analysis was performed using RevMan 5.3 software. Results. A total of 3307 patients were included in the 37 articles. Meta-analysis showed that CXCT significantly increased the total efficiency rate (TER), compared with Western medicine treatment (WMC) (P < 0.00001). When CXCT is combined with WMC, the result showed that P < 0.00001. CXCT was significantly reduced the adverse events (AEs) compared with WMC (P < 0.00001). The levels of VAS, number of migraine episodes (NE), and time of headache duration (TD) were significantly reduced (P < 0.00001). Platelet function and blood rheology level were improved via a significantly decrease in 5-HT and β-EP (P < 0.00001). Other indicators such as substance P, CGRP high-cut viscosity, low-cut viscosity, plasma viscosity, and fibrinogen were significantly reduced (P < 0.00001). Conclusion. Our findings provide evidence that CXCT and CXCT combined with WMC have higher efficacy in the treatment of migraine compared with WCM alone. Methodological quality was generally low, so the conclusion of this paper has some limitations and it has to be carefully evaluated. [ABSTRACT FROM AUTHOR]

The study of artificial microparticles (capsules and vesicles) has gained a growing interest with the emergence of bio-engineering. One of their promoting applications is their use as therapeutic vectors for drug delivery, when capsules and vesicles release their capacity in a targeted environment. The dynamic behavior of capsules and vesicles in confined or unbounded flows was widely studied in the literature and their mechanical response was truthfully described using constitutive laws with good agreement with experiences. However, in a context of biological application, to our knowledge, none of published studies investigating the mechanical response of deformable microparticle took into account the real physiological conditions: the rheological properties of blood such as carrying fluid and the mechanical properties of blood vessels. In this paper, we consider a hyperelastic microparticle suspended in human arteriole. We investigate the deformation of the microparticle resulting from its interaction with blood flow and the arteriolar wall using various capillary numbers and respecting physiological properties of blood and arterial wall. The influence of the blood viscosity model (Newtonian versus shear thinning) is investigated and a comparison with a rigid microchannel and a muscle-embedded arteriole is carried out. The fluid structure interaction (FSI) problem is solved using arbitrary Lagrangian Eulerian (ALE) method. Our simulations have revealed that the arteriolar wall distensibility deeply influences both the deformation and velocity of the microparticle: the deformation strongly increases while the velocity decreases in comparison to an infinitely rigid wall. In the context of therapeutic procedure of targeted drug-delivery, a particular attention should be addressed to these observations, in particular for their implication in the burst mechanism. [ABSTRACT FROM AUTHOR]

The paper presents a study of hemodynamic processes in an artery with stenosis. The Navier–Stokes model and the Carreau model for a non-Newtonian fluid are proposed for computer simulations. Computational experiments were performed using the FlowVision© software. The results of a test simulation for blood flow in the 2D tube, as well as a simulation for the native artery model, based on medical research data, are presented. The simulation results show that in a native artery with a stenosis, the distribution of blood velocity and viscosity may be asymmetric, and their local values differ significantly from the average values observed in the artery after the presumed revascularization. The results have great potential importance for diagnosing and treating arterial stenosis. [ABSTRACT FROM AUTHOR]

In this paper, the effects of hematocrit of red blood cells on blood flow through a stenosed human carotid artery was considered by taking blood as a Newtonian fluid. The governing equations on blood flow were derived. The mathematical content involved in the equations are the variables of interest such as number of stenosis , percentage of hematocrit of red blood cells in the blood, flow rate, wall shear stress, and viscosity of the blood. Guided by medical data collected on the constraint of blood flow in stenosed human carotid arteries, the governing equations were used to check the effects of pressure gradient, wall shear stress, velocity, and volumetric flow rate of blood in the human carotid arteries. Also, the onedimensional equation for the steady and axially symmetric flow of blood through an artery was transformed using Einstein’s coefficient of viscosity and hematocrit of red blood cells with the help of the boundary conditions. The effects of hematocrit on the blood flow characteristics are shown graphically and discussed briefly. It was discovered that the resistance increases as the level of hematocrit increases. Also, the wall shear stress decreases with the increase in the hematocrit level of the red blood cells. [ABSTRACT FROM AUTHOR]

The advances in the treatment of heart failure with Yangxinshi tablet are reviewed in this paper. Yangxinshi tablet has effects of nourishing myocardia, improving myocardial metabolism, reducing myocardial oxygen consumption, dilating coronary artery, improving cardiac blood supply, reducing blood viscosity and improving microcirculation, and it can improve the functions of heart and curative effect of heart failure. [ABSTRACT FROM AUTHOR]

In this paper, we propose a phase field method for the numerical simulations of a moving solid object in two-phase flows. A three-phase Cahn–Hilliard and Navier–Stokes model is employed for this problem. The solid region is represented by a single phase in the three-phase system. The rigidity constraint of the solid phase and the no-slip boundary condition on the solid-fluid interface is imposed by attributing a high viscosity to the solid phase. The solid velocity is then averaged over the solid phase region by the momentum conservation of solid phase. In the aspect of numerics, we design an efficient adaptive finite element method to solve the problem. Several numerical simulation results are given to show the capacity and efficiency of our model and numerical method. [ABSTRACT FROM AUTHOR]

The Fåhræus-Lindqvist effect is usually explained from a physical point of view with the so-called Haynes' marginal zone theory, i.e., migration of red blood cells (RBCs) to a core layer surrounded by an annular RBCs-free plasma layer. In this paper we show that the marginal layer, though causing a substantial reduction in flow resistance and increasing discharge, does not reduce the rate of energy dissipation. This fact is not surprising if one considers the electric analog of the flow in a vessel: a resistance reduction increases both the current intensity (i.e., the discharge) and the energy dissipation. This result is obtained by considering six rheological models that relate the blood viscosity to hematocrit (volume fraction occupied by erythrocytes). Some physiological implications are discussed. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we have proposed a new non-linear constitutive model for blood with a viscosity which depends on the shear rate and the volume fraction of red blood cells or RBCs (hematocrit). The viscosity correlation is obtained from the experimental data reported in the literature. The governing equations for flow between two flat plates are made dimensionless and solved numerically. A parametric study is performed to study the effect of the four non-dimensional numbers K 1 (a relative measure of the pressure gradient to viscous forces), K 2 (a relative measure of gravitational force to pressure gradient in the direction of the gravity), N (dimensionless average hematocrit of blood), and ϕ m (maximum packing fraction of RBCs). The results show good qualitative agreement with other studies. [ABSTRACT FROM AUTHOR]

The ideal hematocrit is the hematocrit (Hct) value resulting in the highest value of Hct/viscosity (h/η) ratio and can thus be predicted from viscometric measurements with the use of equations such as Quemada's one which yield the determination of the bell-shaped curve of h/η as a function of Hct. In a series of recent papers we applied this approach to various populations, using viscometry at high shear rate (1000 s–1). However the shape of this curve has been reported to be dependent on the shear rate, resulting in a right-shift in this top value when Hct increase. We present here in 11 young recreative athletes the evolution of the predicted top of the h/η curve and optimal theoretical Hct and the discrepancy between theoretical and optimal values over the range of shear rates 1 to 6000 s–1. Results show that the predicted optimal value of both h/η and Hct increases when shear rate increases and that the discrepancy between predicted laquooptimalraquo and actual values decreases and becomes almost asymptotic at very high shear (500 s–1). It is minimal at 2720 s–1. The correlation between predicted laquooptimalraquo and actual values of both parameters describes the same evolution. Therefore, it is better for assessing h/η and its agreement with theoretical values, and for determining the theoretical ideal hematocrit, to measure blood viscosity at shear rates equal or superior to 500 s–1. [ABSTRACT FROM AUTHOR]

Abstract Marine resources are limited and optimal utilisation of all the available material is essential to ensure sustainability. This brings two main challenges: the first is to get the maximum quantity and quality out of the catch of high value-added raw material. The second is to upgrade low value-added raw material such as blood-waters. The volume of blood-waters generated from pelagic processing industries and their organic load varies from species to species but volumes are large and costs associated with disposal are substantial. However, pelagic blood-water waste streams contain proteins, lipids and small molecules with potential for use in food and feed. The dog and cat feed and food industry is a lucrative sector which is currently valued at $42 billion and is considerably larger than the worldwide baby food market. Furthermore, blood-water from processing is a substantial environmental and economic cost for pelagic processors. To date, the utilisation of blood-waters as food and feed ingredients has not been intensively reviewed. The central focus of this paper is to provide a comprehensive and critical review of recent progress in the recovery of proteins and other molecules from pelagic fish derived blood-waters using filtration and other methods which have potential for use by food and feed industries. The current and potential applications of blood-waters are discussed and the review confirms that blood-water recovery technologies are viable and environmentally beneficial but production efficiency and costs should be improved. The review also provides analysis of challenges that exist concerning the development of ingredients from this resource including the relevant legislation and regulation governing access/use of blood-water and limitations that can be encountered in the development of products. Recent research indicates that proteins derived from blood-waters which are obtained in properly managed processing plants can be considered safe if handled correctly and have potential to replace proteins from other sources in fish and feed manufacture. It is recommended that the safety of recovered pelagic blood-waters in terms of the microbial and heavy metal load is assessed prior to use and that further research should be carried out in conjunction with industry to reduce costs associated with implementation of successful filtration methods. This review provides scientific value for marine and food scientists concerning recovery and utilisation strategies of pelagic processing blood-waters and this may be used to inform industry and environmental policy makers in the future. Graphical abstract Image 1 Highlights • Review collates the current state-of-the-art concerning treatment of blood-water prior to release at sea. • Details potential markets and challenges associated with these markets for proteins recovered from bloodwaters. • Details potential health and technofunctional properties of recovered blood-water proteins. [ABSTRACT FROM AUTHOR]

Establishment of real‐time monitoring technique for blood viscosity during extracorporeal treatment is strongly desired. We have demonstrated that the red blood cell aggregation degree, which highly correlates with the blood viscosity, can be estimated by the microscopic observation of the red blood cell over a transparent blood circuit tube and the two‐dimensional correlation process executed between time different images. In this paper, for estimation precision improvement, a maximum likelihood design of correlation region based on calculation of local flow vector has been attempted. [ABSTRACT FROM AUTHOR]

Dried blood spots (DBS) are a versatile and stable tool for direct clinical blood analysis. Ambient high-resolution mass spectrometry is emerging as a method of choice for their quantitative analysis, for instance in therapeutic drug monitoring. Here, we coupled liquid microjunction surface sampling technology, a so-called Flowprobe, with an Orbitrap mass spectrometer and demonstrated the utility of this set-up for direct quantification of multiple drugs in DBS on filter paper. A three-layer set-up that we had introduced earlier enabled introduction of internal standards into DBS. We furthermore took an established point-of-care test system a step further and analyzed disposable test fields for blood glucose monitoring also for Flowprobe-based acetaminophen screening without additional sample preparation. Using as little as 2 μL blood, the method had an LOD of 1 μg mL−1 (coefficient of variation of ≤15%) and acetaminophen recoveries of 82 to 119% for blinded samples, as assessed by LC-MS/MS. Half an hour after ingestions of a single 1000 mg acetaminophen dose, indistinguishable drug levels were measured in three healthy volunteers by LC-MS/MS and Flowprobe-Orbitrap MS analysis of DBS. Flowprobe analysis of DBS was 6- to 100-times more sensitive than corresponding desorption electrospray ionization MS analysis for four drugs. For instance, the LOD for salicylic acid analysis was 0.07 ng mL−1 with Flowprobe measurement. Furthermore, we showed that multi-component analysis of five different substances, which may mimic polypharmacy in diabetes patients, in one blood sample for screening purposes was feasible. Taken together, our study suggests that microjunction surface sampling of DBS on filter paper and disposable point-of-care test fields may be developed into routine methods for near-patient multi-compound therapeutic drug monitoring that may advance blood screening analysis for patients with polypharmacy. [ABSTRACT FROM AUTHOR]

Blood is one of the most important biofluids used for clinical diagnostics. Cells and proteins in the blood can provide a rich source of information for the evaluation of human health. Efficient separation of blood components is a necessary process in order to minimize the interference of unwanted components during sensing, separation, and detection. In this paper, an insulator-based gradient dielectrophoretic device has been applied to separate red blood cells from model protein biomarkers for myocardial infarction in buffer. Within one min, red blood cells are largely depleted regardless of the minimum adherence on the channel wall. Considering the adhered red blood cells will not be transported further, a purified protein solution can be delivered for potential downstream processing or detection. [ABSTRACT FROM AUTHOR]

In microcirculation, red blood cells (RBCs) tend to migrate toward the centre of the vessel leaving a region of a cell depleted layer or cell-free layer (CFL) at the vessel wall and a core of RBCs at the centre. This heterogenous distribution of cells has an effect on the blood apparent viscosity and the exchanges of gases and nutrients between the RBCs and the vessel. Understanding the formation of the CFL and obtaining accurate measurement of it is paramount for furthering development of devices such as drug administration. This paper presents a general semi-automatic method to quantify the thickness of the CFL for different channel geometries and image quality. It enables the use of a method based on intensity, a method using the gradient of the intensity, or a method based on spatiotemporal variation. The main features are reported, the performance is demonstrated on experimentally obtained image sets and accuracy is validated using synthetic images with known CFL thickness. A pure automatic detection is limited by the most visually correct using the spatiotemporal method, however proposed thresholding through automatic detection allows for quality controls through manual adjustments. With a semi-automatic approach RBC core variability between 3 % to 8 % was found when the test user was tasked with repeating the analysis of the same set. The presented method provides, users without programming ability with a user-friendly interface that can extract CFL automatically with quality control through manual adjustments. • Detection of channel walls, diameter measurement • Automatic or semis-automatic detection of the red blood cell core • User interface with visual feedback and manual adjustment • Batch processing • Thorough verification of the software for this application [ABSTRACT FROM AUTHOR]

This paper proposes an algorithm that estimates blood viscosity during cardiopulmonary bypass (CPB) and validates its application in clinical cases. The proposed algorithm involves adjustable parameters based on the oxygenator and fluid types and estimates blood viscosity based on pressure-flow characteristics of the fluid perfusing through the oxygenator. This novel nonlinear model requires four parameters that were derived by in vitro experiments. The results estimated by the proposed method were then compared with a conventional linear model to demonstrate the former's optimal curve fitting. The viscosity (\eta e) estimated using the proposed algorithm and the viscosity (\eta) measured using a viscometer were compared for 20 patients who underwent mildly hypothermic CPB. The developed system was applied to ten patients, and \eta _{e} was recorded for comparisons with hematocrit and blood temperature. The residual sum of squares between the two curve fittings confirmed the significant difference, with p < 0.001. \eta _{e} and \eta showed a very strong correlation with R^{2} = 0.9537 and p < 0.001. Regarding the mean coefficient of determination for all cases, the hematocrit and temperature showed weak correlations at 0.33 ± 0.14 and 0.22 ± 0.21, respectively. For CPB measurements of all cases, \eta _{e}$ was more than 98% distributed in the range from 1 to 3 mPa⋅s. This new system for estimating viscosity may be useful for detecting various viscosity-related effects that may occur during CPB. [ABSTRACT FROM AUTHOR]

Background: A normal number of T-cell receptor excision circles (TRECs) and K-deleting recombination excision circles (KRECs) is considered a biomarker for adequate new T- and B-cell production. In newborns, detection of TRECs and KRECs by real time PCR from dried blood spotted on filter paper is used for the screening of severe immunodeficiency. In adults, elderly and during diseases, where the number of TRECs is lower than in newborns and children, a large amount of DNA and a sensitive method of amplification are necessary to identify newly produced lymphocytes.Methods: DNA was prepared from blood of 203 healthy adults (range: 18-91 years old) absorbed for 10 s on flocked swabs and let to dry, or from peripheral blood mononuclear cells. DNA was subjected to digital PCR and to well established conventional real time PCR-based method using TREC- and KREC-specific primers and probes. The number of TRECs and KRECs was expressed per mL of blood. Statistical analysis was performed by nested ANOVA, Pearson coefficient of determination, and by linear regression tests.Results: The novel method for the storage of dried blood on nylon flocked swabs and the use of digital PCR allow quantification of TRECs and KRECs with high degree of sensitivity, specificity, accuracy, and precision. TRECs and KRECs were amplified by digital PCR in all tested blood samples, including those obtained from elderly individuals (>70 years old) and that were negative by real time PCR. Furthermore, values of TRECs and KRECs obtained by digital PCR were in the range of those acquired by real time PCR.Conclusions: Our findings demonstrate that DNA isolation from dried blood on flocked swabs followed by digital PCR-based analysis represents a useful tool for studying new lymphocyte production in adults and elderly individuals. This suggests the potential use of the methodology when monitoring of clinical variables is limited by the number of molecules that can be amplified and detected, such as in patients with immunodeficiency or under immunosuppressive therapies. [ABSTRACT FROM AUTHOR]

Introduction Information on the prevalence of lead exposure is essential to formulate efficient public health policies. Developed countries have implemented successful public policies for the prevention and control of lead poisoning. In the United States, Canada, Japan and the European Union, for instance, periodically repeated prevalence studies show that blood lead levels (BLLs) in children have decreased overall. Although BLL of Latino children in the U.S. have also dropped in recent years, the geometric mean remains higher than that of white children. Little is known about lead exposure in children in Latin America and the Caribbean (LAC). In this review, we responded to two questions: What is currently known about lead sources and levels in children in LAC? Are there public policies to prevent children's exposure to lead in LAC? Method We conducted a literature review covering the period from January 2000 to March 2014 in the PubMed and Lilacs databases to obtain English, Portuguese and Spanish language studies reporting the prevalence of BLLs in children aged 0–18 years living in LAC countries. No specific analytical method was selected, and given the scarcity of data, the study was highly inclusive. Results Fifty-six papers were selected from 16 different LAC countries. The children's BLLs found in this review are high (≥ 10 μg/dL) compared to BLLs for the same age group in the U. S. However, most studies reported an association with some type of “lead hot spot”, in which children can be exposed to lead levels similar to those of occupational settings. Only Peru and Mexico reported BLLs in children from population-based studies. Conclusions Most BLLs prevalence studies carried out in LAC were in areas with known emission sources. The percentage of children at risk of lead poisoning in LAC is unknown, and probably underestimated. Thus, there is an urgent need to establish public health policies to quantify and prevent lead poisoning, specifically by prioritizing the identification and control of “hot spots”. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model capable to reproduce a celebrated phenomenon in blood microcirculation known as Fåhræus effect, since its discovery by Robin Fåhræus (1929). This consists in a decaying of the relative hematocrit in small vessels as the vessel diameter decreases. The key point of the model is a formula, direct consequence of the basic principles of fluid dynamics, that links the relative hematocrit to the reservoir hematocrit and the vessel diameter, which confirms the observed behavior. To test the model we selected, among the few experiments carried on since then, those performed by Barbee and Cokelet (1971). The agreement is remarkable. An extended comparison is also carried out with a celebrated empirical formula proposed by Pries et al. (1992) to describe the same phenomenon. • Modeling of blood flow in medium–large microvessels. • Theoretical description of the Fåhræus effect. • Explicit formulas for H T as a function of H D. • Comparison with the Barbee–Cokelet experiments. [ABSTRACT FROM AUTHOR]

The current study deals with the mathematical modelling and analysis of the effects of thermoregulation on blood viscosity under magnetic and thermal radiation effects on a permeable, stretching blood capillary. The model comprises the governing equations of the resulting boundary layer problem, which is a set of nonlinear partial differential equations, and this is transformed into a coupled system of nonlinear differential equations using similarity transformation. The numerical solution of the problem is attained by the fourth-order Runge Kutta method with the shooting method. The current work examines the velocity and temperature profile of blood flow with the impact of varying temperature-dependent blood viscosity, involving the variation of several physical parameters such as magnetic field, radiation parameter, permeability parameter, Prandtl number, and surface temperature, as well as their physical interpretation. During certain therapies, the thermoregulation mechanism in humans causes a change in blood flow behaviour. Also, blood flow must be regulated during pathological conditions with the help of radiation, heat, or magnetic effects. It is found that, due to the varying viscosity parameter, the magnetic field effect inhibits heat transport in the body. It has also been found that increasing the permeability parameter enhances mass and heat transfer. The results of this paper could be important in analysing and regulating blood flow and body temperature during hypothermia and hyperthermia therapies. • Mathematical analysis of the Newtonian model of blood flow with viscosity variation is carried out. • Heat transfer at the vessel wall is reduced by magnetic and thermal radiation effects. • The body's thermoregulatory response to magnetic and thermal effects is investigated. • Rising the permeability of the blood vessel wall increases the heat transfer rate. • Blood temperature rises as the radiation effect and the surface temperature rise. [ABSTRACT FROM AUTHOR]

An obvious candidate for the seminal event in the history of haemorheology is Harvey's presentation of the concept of the circulation of the blood. Prior to this, the ideas concerning the movement of blood were based, in Europe and Middle East, largely on the principles laid down by Galen, and these had been, in effect, dogma for nearly a millennium and a half. These principles were basically that blood is formed in the liver, thence it travels to the bodily organs and is consumed - hence there is one-way flow and no circulation of the blood at all. Harvey's revolutionary idea that blood circulates repeatedly around the cardiovascular system laid the foundation for haemorheology because once that idea was accepted then the fluidity of the blood immediately became potentially of crucial importance - and haemorheology was conceived. In this paper the ideas that preceded Harvey will be presented, i.e. those of Galen, Ibn al-Nafis, Vesalius, Fabricius and Colombo etc. Harvey's awareness of this background, due mainly to time spent in Padua, triggered his many experimental investigations and discoveries. Ultimately, these led to his astonishing insights published in De Mortu Cordis in 1628 which changed the understanding of the cardio-vascular system forever. [ABSTRACT FROM AUTHOR]

Physiological studies on fetal blood in narrow glass tubes have suggested that fetal optimal hematocrit (hct) might be as high as 60%. A theoretical 'ideal' hct can also be predicted with a theoretical curve of hematocrit/viscosity (h/η) ratio vs hct constructed with Quemada's model. We used the database of one of our previous papers on fetal hemorheology to reinterpret its results with this concept. A series of 28 intrauterine cord punctures (between 19 and 33 weeks gestation) with doppler measurements of resistance in umbilical arteries was studied. The theoretical 'optimal hematocrit' was well correlated to actual (r = 0.857, p < 0.01) but systematically lower (Bland-Altman plot +12.1[8.52-15.7]) than the actual one. Umbilical artery resistance index is correlated with actual hematocrit (r = 0.407, p < 0.05), the discrepancy between ideal and actual (r = -0.542, p < 0.05) but not predicted ideal hematocrit, suggesting that the discrepancy between ideal and actual may reflect an adaptative decrease aiming at reducing vascular resistance. These findings indicate that prediction of ideal hematocrit with Quemada's equation makes sense in fetal blood, and suggest that a 'viscoregulatory mechanism' maintains hematocrit below this theoretical value in order to avoid excess vascular resistance. [ABSTRACT FROM AUTHOR]

Since blood viscosity is a basic parameter for understanding hemodynamics in human physiology, great amount of research has been done in order to accurately predict this highly non-Newtonian flow property. However, previous works lacked in consideration of hemodynamic changes induced by heterogeneous vessel networks. In this paper, the effect of bifurcation on hemodynamics in a microvasculature is quantitatively predicted. The flow resistance in a single bifurcation microvessel was calculated by combining a new simple mathematical model with 3-dimensional flow simulation for varying bifurcation angles under physiological flow conditions. Interestingly, the results indicate that flow resistance induced by vessel bifurcation holds a constant value of approximately 0.44 over the whole single bifurcation model below diameter of 60 μm regardless of geometric parameters including bifurcation angle. Flow solutions computed from this new model showed substantial decrement in flow velocity relative to other mathematical models, which do not include vessel bifurcation effects, while pressure remained the same. Furthermore, when applying the bifurcation angle effect to the entire microvascular network, the simulation results gave better agreements with recent in vivo experimental measurements. This finding suggests a new paradigm in microvascular blood flow properties, that vessel bifurcation itself, regardless of its angle, holds considerable influence on blood viscosity, and this phenomenon will help to develop new predictive tools in microvascular research. [ABSTRACT FROM AUTHOR]

References 1 Lim PN, Wylie G. Symmetrical drug-related intertriginous and flexural exanthema like eruption associated with COVID-19 vaccination. COVID-19 vaccination and exanthema-like eruption Dear Editor, We read with interest the paper by Lim and Wylie1 published recently in I Clinical and Experimental Dermatology i , in which they proposed a possible association between an exanthema-like eruption of the skin and the administration of the ChAdOx1 nCoV-19 (AstraZeneca-Oxford) COVID-19 vaccine. [Extracted from the article]

Advanced personalized medical diagnostics depend on the availability of high-quality biological samples. These are typically biofluids, such as blood, saliva, or urine; and their collection and storage is critical to obtain reliable results. Without proper temperature regulation, protein biomarkers in particular can degrade rapidly in blood samples, an effect that ultimately compromises the quality and reliability of laboratory tests. Here, we present the use of silk fibroin as a solid matrix to encapsulate blood analytes, protecting themfrom thermally induced damage that could be encountered during nonrefrigerated transportation or freeze-thaw cycles. Blood samples are recovered by simple dissolution of the silk matrix in water. This process is demonstrated to be compatible with a number of immunoassays and provides enhanced sample preservation in comparison with traditional air-drying paper approaches. Additional processing can remediate interactions with conformational structures of the silk protein to further enhance blood stabilization and recovery. This approach can provide expanded utility for remote collection of blood and other biospecimens empowering new modalities of temperature- independent remote diagnostics. [ABSTRACT FROM AUTHOR]