Transporting water and oil microdroplets is important for applications ranging from water harvesting to biomedical analysis but remains a great challenge. This is due to the amplified contact angle ...hysteresis and insufficient driving force in the micrometer scale, especially for low-surface energy oil droplets. Coalescence of neighboring droplets, which releases vast additional surface energy, was often required, but its relatively uncontrollable nature brings uncertainties to the droplet motion, and the methodology is not applicable to single droplets. Here we introduce a strategy based on slippery surface with immobilized lubricant menisci to directionally transport microdroplets. By simply mounting hydrogel dots on slippery surface, the raised menisci remotely pump microdroplets via capillary force with high efficiency, regardless of droplet size or surface energy. By proof-of-concept experiments, we demonstrate that our method allows for highly efficient water droplet collection and highly sensitive biomedical analyte detection.
The effect of red blood cells and the undulation of the endothelium on the shear stress in the microvasculature is studied numerically using the lattice Boltzmann–immersed boundary method. The ...results demonstrate a significant effect of both the undulation of the endothelium and red blood cells on wall shear stress. Our results also reveal that morphological alterations of red blood cells, as occur in certain pathologies, can significantly affect the values of wall shear stress. The resulting fluctuations in wall shear stress greatly exceed the nominal values, emphasizing the importance of the particulate nature of blood as well as a more realistic description of vessel wall geometry in the study of hemodynamic forces. We find that within the channel widths investigated, which correspond to those found in the microvasculature, the inverse minimum distance normalized to the channel width between the red blood cell and the wall is predictive of the maximum wall shear stress observed in straight channels with a flowing red blood cell. We find that the maximum wall shear stress varies several factors more over a range of capillary numbers (dimensionless number relating strength of flow to membrane elasticity) and reduced areas (measure of deflation of the red blood cell) than the minimum wall shear stress. We see that waviness reduces variation in minimum and maximum shear stresses among different capillary and reduced areas.
To make a propensity-score matching analysis on the clinical application of gastric-jejunum pouch anastomosis (GJPA) and continuous jejunal pouch and residual stomach anastomosis combined with ...jejunal lateral anastomosis (Contin-L).
The clinic data of 287 patients who received distal gastrectomy from January 2015 to January 2019 were collected retrospectively. The enrolled patients were divided into the GJPA group and the Contin-L group according to the reconstruction method used. Clinical data and operation complications were analyzed.
Compared with Contin-L group, the duration of digestive tract reconstruction in the GJPA group was shorter, and the overall cost in the GJPA group was lower. No obvious intergroup differences were found in other intraoperative data, early surgical outcomes, incidence rates of reflux gastritis, anastomotic ulcer, postoperative nutritional and hematological indicators. The postoperative subjective feelings in the GJPA group were similar with those in the Contin-L groups.
Addition of jejunal lateral anastomosis is not necessary for GJPA following distal gastrectomy.
•Blood flow constantly interacts with chemical signaling.•Blood flow and chemical signaling coupling is achieved via lattice Boltzmann method.•Drug delivery by liposomes and ATP release by ...erythrocytes are addressed applications.
Diffusion of solutes is often encountered in many biological processes. In the blood micro circulation system, solutes, such as oxygen and calcium molecules, as well as Adenosine Triphosphate (ATP) and biochemical messengers, are released by cells (like red blood and endothelial cells), and are dispersed via diffusion and advection. Moreover, several targeted drug delivery strategies rely on an encapsulation of chemicals and on their release in the blood stream at specific location. The released chemicals couple to blood flow, in which red blood cells (RBCs) constitute the major component. Thus, the development of numerical methods which take into account both dynamics of RBCs and their coupling with chemicals is of great importance for many biomedical applications. We develop here a lattice-Boltzmann based method that deals with generic moving boundary conditions in an advection-diffusion field representing the chemicals. The boundary condition of the solutes at the cell membrane is based on a modified bounce-back scheme. We prove analytically, and validate numerically, that it enjoys second order precision. The solver is validated with several benchmarks and is then coupled with a solver for a suspension of RBCs, we developed previously. We then exemplify the method on the problem of liposome drug delivery in arterioles. The results show that for a rigid drug carrier at a scale of about 1 μm, the presence of RBCs facilitates the drug absorption along the vessel wall. We also exemplify the solver for the release of chemicals induced by membrane shear stress, a feature which is omnipresent in mechano-involved signaling processes. As a way of example, we briefly study the problem of ATP release by RBCs. We point out several possible generalizations.
ATP is not only an energy carrier but also serves as an important signalling molecule in many physiological processes. Abnormal ATP level in blood vessel is known to be related to several ...pathologies, such as inflammation, hypoxia and atherosclerosis. Using advanced numerical methods, we analysed ATP released by red blood cells (RBCs) and its degradation by endothelial cells (ECs) in a cat mesentery-inspired vascular network, accounting for RBC mutual interaction and interactions with vascular walls. Our analysis revealed a heterogeneous ATP distribution in the network, with higher concentrations in the cell-free layer, concentration peaks around bifurcations and heterogeneity among vessels of the same level. These patterns arise from the spatio-temporal organization of RBCs induced by the network geometry. It is further shown that an alteration of hematocrit and flow strength significantly affects ATP level as well as heterogeneity in the network. These findings constitute a first building block to elucidate the intricate nature of ATP patterns in vascular networks and the far reaching consequences for other biochemical signalling, such as calcium, by ECs.
ATP release by red blood cells (RBCs) under shear stress (SS) plays a pivotal role in endothelial biochemical signaling cascades. The aim of this study is to investigate through numerical simulation ...how RBC spatiotemporal organization depends on flow and geometrical conditions to generate ATP patterns. Numerical simulations were conducted in a straight channel by considering both plasma and explicit presence of RBCs, their shape deformation and cell-cell interaction, and ATP release by RBCs. Two ATP release pathways through cell membrane are taken into account: pannexin 1 channel, sensitive to SS, and cystic fibrosis transmembrane conductance regulator, which responds to cell deformation. Several flow and hematocrit conditions are explored. The problem is solved by the lattice Boltzmann method. Application of SS to the RBC suspension triggers a nontrivial spatial RBC organization and ATP patterns. ATP localizes preferentially in the vicinity of the cell-free layer close to channel wall. Conditions for maximal ATP release per cell are identified, which depend on vessel size and hematocrit Ht. Increasing further Ht beyond optimum enhances the total ATP release but should degrade oxygen transport capacity, a compromise between an efficient ATP release and minimal blood dissipation. Moreover, ATP is boosted in capillaries, suggesting a vasomotor activity coordination throughout the resistance network.
Here, we describe a simple method to prepare oil-repellent surfaces with inherent reactivity. Liquid-like copolymers with pendant reactive groups are covalently immobilized onto substrates via a ...sequential layer-by-layer method. The stable and transparent nanocoatings showed oil repellency to a broad range of organic liquids even in the presence of reactive sites. Functional molecules could be covalently immobilized onto the oil-repellent surfaces. Moreover, the liquid repellency can be maintained or finely tailored after post-chemical modification via synergically tailoring the film thickness, selection of capping molecules, and labeling degree of the capping molecules. Oil-repellent surfaces that are capable of post-functionalization would have technical implications in surface coatings, membrane separation, and biomedical and analytical technologies.
The prognostic significance of tumor-infiltrating immune cells in endometrial cancer is a subject of ongoing debate. Recent evidence increasingly suggests that these immune cells and cytokines, ...abundant in endometrial cancer tissues, play a pivotal role in stimulating the body inherent anti-tumor immune responses.
Leveraging publicly accessible genetic data, we conducted an exhaustive 2-sample Mendelian randomization (MR) study. This study aimed to explore the causal links between 731 immunophenotypes and the risk of endometrial cancer. We thoroughly assessed the robustness, heterogeneity, and potential horizontal pleiotropy of our findings through extensive sensitivity analyses.
Our study identified 36 immunophenotypes associated with endometrial cancer risk. Specific immunophenotypes, such as the percentage of Naive-mature B-cells in lymphocytes (OR = 0.917, 95% CI = 0.863-0.974, P = .005), and HLA DR expression on CD14-CD16 + monocytes (OR = 0.952, 95% CI = 0.911-0.996, P = .032), exhibited a negative correlation with endometrial cancer. Conversely, CD127 expression on CD45RA + CD4 + in Treg cells (OR = 1.042, 95% CI = 1.000-1.085, P = .049), and CM CD4+%T in T cell maturation stages (OR = 1.074, 95% CI = 1.012-1.140, P = .018) showed a positive correlation. Reverse MR analysis linked endometrial cancer to 4 immunophenotypes, including a positive correlation with CD127-CD8br %T cell of Treg (OR = 1.172, 95% CI = 1.080-1.270, P = .0001), and negative correlations with 3 others, including CM CD4+%T cell (OR = 0.905, 95% CI = 0.832-0.984, P = .019).
Our findings underscore a significant causal relationship between immunophenotypes and endometrial cancer in bidirectional MR analyses. Notably, the CM CD4+%T immunophenotype emerged as potentially crucial in endometrial cancer development.
ATP is a major player as a signaling molecule in blood microcirculation. It is released by red blood cells (RBCs) when they are subjected to shear stresses large enough to induce a sufficient shape ...deformation. This prominent feature of chemical response to shear stress and RBC deformation constitutes an important link between vessel geometry, flow conditions, and the mechanical properties of RBCs, which are all contributing factors affecting the chemical signals in the process of vasomotor modulation of the precapillary vessel networks. Several in vitro experiments have reported on ATP release by RBCs due to mechanical stress. These studies have considered both intact RBCs as well as cells within which suspected pathways of ATP release have been inhibited. This has provided profound insights to help elucidate the basic governing key elements, yet how the ATP release process takes place in the (intermediate) microcirculation zone is not well understood. We propose here an analytical model of ATP release. The ATP concentration is coupled in a consistent way to RBC dynamics. The release of ATP, or the lack thereof, is assumed to depend on both the local shear stress and the shape change of the membrane. The full chemo-mechanical coupling problem is written in a lattice-Boltzmann formulation and solved numerically in different geometries (straight channels and bifurcations mimicking vessel networks) and under two kinds of imposed flows (shear and Poiseuille flows). Our model remarkably reproduces existing experimental results. It also pinpoints the major contribution of ATP release when cells traverse network bifurcations. This study may aid in further identifying the interplay between mechanical properties and chemical signaling processes involved in blood microcirculation.
The rheological behavior and dynamics of a vesicle suspension, serving as a simplified model for red blood cells, are explored within a Poiseuille flow under the Stokes limit. Investigating vesicle ...response has led to the identification of novel solutions that complement previously documented forms like the parachute and slipper shapes. This study has brought to light the existence of alternative configurations, including a fully off-centered form and a multilobe structure. The study unveils the presence of two distinct branches associated with the slipper shape. One branch arises as a consequence of a supercritical bifurcation from the symmetric parachute shape, while the other emerges from a saddle-node bifurcation. Notably, the findings are represented through diagrams that display data collapsing harmoniously based on a combination of independent dimensionless parameters. Delving into the rheological implications, a remarkable observation emerges: the normalized viscosity (
i.e.
similar to intrinsic viscosity) exhibits a non-monotonic trend as a function of vesicle concentration. Initially, the normalized viscosity diminishes as the concentration increases, followed by a subsequent rise at higher concentrations. Noteworthy is the presence of a minimum value in the normalized viscosity at lower concentrations, aligning well with the concentrations observed in microcirculation scenarios. The intricate behavior of the normalized viscosity can be attributed to a delicate spatial arrangement within the suspension. Importantly, this trend echoes the observations made in a linear shear flow scenario, thereby underscoring the universality of the rheological behavior for confined suspensions.
We study the rheological behavior and dynamics of vesicles in a Poiseuille flow, unveiling the presence of two distinct branches with slipper shapes and the non-monotonic trend of the normalized viscosity as a function of vesicle concentration.
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