Self-Healing Polymers Coupling Shape Memory Effect.

In recent years, shape memory polymers (SMPs) and self-healing polymers (SHPs) have been research hotspots in the field of smart polymers owing to their unique stimulus response mechanisms. Previous research on SHPs has primarily focused on contact repair. However, in instances where substantial cracks occur during practical use, autonomous closure becomes challenging, impeding effective repair. By integration of the shape memory effect (SME) with SHPs, physical wound closure can be achieved via the SME, facilitating subsequent chemical/physical repair processes and enhancing self-healing effectiveness. This article reviews key findings from previous research on shape memory-assisted self-healing (SMASH) materials and addresses the challenges and opportunities for future investigation.

Prediction of high-intensity focused ultrasound (HIFU)-induced lesion size using the echo amplitude from the focus in tissue.

In the realm of high-intensity focused ultrasound (HIFU) therapy, the precise prediction of lesion size during treatment planning remains a challenge, primarily due to the difficulty in quantitatively assessing energy deposition at the target site and the acoustic properties of the tissue through which the ultrasound wave propagates. This study investigates the hypothesis that the echo amplitude originating from the focus is indicative of acoustic attenuation and is directly related to the resultant lesion size. Echoes from multi-layered tissues, specifically porcine tenderloin and bovine livers, with varying fat thickness from 0 mm to 35 mm were collected using a focused ultrasound (FUS) transducer operated at a low power output and short duration. Subsequent to HIFU treatment under clinical conditions, the resulting lesion areas in the ex vivo tissues were meticulously quantified. A novel treatment strategy that prioritizes treatment spots based on descending echo amplitudes was proposed and compared with the conventional raster scan approach. Our findings reveal a consistent trend of decreasing echo amplitudes and HIFU-induced lesion areas with the increasing fat thickness. For porcine tenderloin, the values decreased from 2541.7 ± 641.9 mV and 94.4 ± 17.9 mm2 to 385(342.5) mV and 24.9 ± 18.7 mm2, and for bovine liver, from 1406(1202.5) mV and 94.4 ± 17.9 mm2 to 502.1 ± 225.7 mV and 9.4 ± 6.3 mm2, respectively, as the fat thickness increases from 0 mm to 35 mm. Significant correlations were identified between preoperative echo amplitudes and the HIFU-induced lesion areas (R = 0.833 and 0.784 for the porcine tenderloin and bovine liver, respectively). These correlations underscore the potential for an accurate and dependable prediction of treatment outcomes. Employing the proposed treatment strategy, the ex vivo experiment yielded larger lesion areas in bovine liver at a penetration depth of 8 cm compared to the conventional approach (58.84 ± 17.16 mm2 vs. 44.28 ± 15.37 mm2, p < 0.05). The preoperative echo amplitude from the FUS transducer is shown to be a reflective measure of acoustic attenuation within the wave propagation window and is closely correlated with the induced lesion areas. The proposed treatment strategy demonstrated enhanced efficiency in ex vivo settings, affirming the feasibility and accuracy of predicting HIFU-induced lesion size based on echo amplitude.

ß-cyclodextrin modified GO ultrafiltration membranes with enhanced antifouling property for water purification.

The study investigated the influence of additives on the fabrication of mixed matrix membranes comprising polyethersulfone (PES), with a specific focus on hydrophilicity, flux, morphology, and antifouling properties. Carboxymethyl modified ß-cyclodextrin (CMß-CD) was used to enhance the dispersion and hydrophilicity of graphene oxide (GO), leading to the formation of a hydrophilic and stable composite nanoparticle (CMCD@GO). The hydrophilicity (WCA <51.5°) and water flux (32.6 L.m-2.h-1) of the modified PES membranes (MCDGO-x) were improved by the incorporation of CMCD@GO nanoparticles, while that of PES membrane was 79.7° and 10.6 L.m-2.h-1. The rate of backscattered light intensity (ΔBS) of MCDGO-x suspensions remains stable, suggesting stable dispersion of CMCD@GO in organic solvents. Compared to the bare PES membrane, the MCDGO-x membrane exhibits a thinner active layer and a finger-like structure. The MCDGO-x membrane exhibited excellent naphthenic acids (NAs) rejection (> 93.2%) due to reduced roughness and higher hydrophilicity, while the GO-modified PES membrane (MGO-5) exhibited lower NAs rejection (87.2%). Furthermore, the MCDGO-5 membrane showed higher flux recovery ratio (FRR) of 79.3% compared to MGO-5 membrane (68.5%) after three cycles, indicating the antifouling performance of MCDGO-x for NAs was significantly improved. The combination of CMß-CD and GO enhance the flux and antifouling properties of PES ultrafiltration membranes, suggesting significant potential for applications in the purification of oil sands process water and the treatment of oily wastewater.

Peroxymonosulfate activation by iron-cobalt bimetallic phosphide modified nickel foam for efficient dye degradation.

Novel catalysts with multiple active sites and rapid separation are required to effectively activate peroxymonosulfate (PMS) for the removal of organic pollutants from water. Therefore, an integrated catalyst for PMS activation was developed by directly forming Co-Fe Prussian blue analogs on a three-dimensional porous nickel foam (NF), which were subsequently phosphorylated to obtain cobalt-iron bimetallic phosphide (FeCoP@NF). The FeCoP@NF/PMS system efficiently degraded dye wastewater within 20 min. The system exhibited excellent catalytic degradation over a broad pH range and at high dye concentrations due to the presence of unique asymmetrically charged Coa+ and Pb- dual active sites formed by cobalt phosphides within FeCoP@NF. These active sites significantly enhanced the catalytic activity of PMS. The activation mechanism of PMS involves phosphorylation that accelerates electron transfer from FeCoP@NF to PMS, to generate SO4·-, ·OH, O2·-, and 1O2 active species. Three-dimensional FeCoP@NF could be readily recycled and showed good stability for PMS activation. In this study, a highly efficient, stable, and readily recyclable integrated catalyst was developed. This catalyst system effectively resolves the separation and recovery issues associated with conventional powder catalysts and has a wide range of potential applications in wastewater treatment.

Defective nitrogen doped carbon material derived from nano-ZIF-8 for enhanced in-situ H2O2 generation and tetracycline hydrochloride degradation in electro-Fenton system.

Tetracycline hydrochloride (TC) accumulates in large quantities in the water environment, causing a serious threat to human health and ecological environment safety. This research focused on developing cost-effective catalysts with high 2e- selectivity for electro-Fenton (EF) technology, a green pollution treatment method. Defective nitrogen-doped porous carbon (d-NPC) was prepared using the metal-organic framework as the precursor to achieve in-situ H2O2 production and self-decomposition into high activity ·OH for degradation of TC combined with Co2+/Co3+. The d-NPC produced 172.1 mg L-1 H2O2 within 120 min, and could degrade 96.4% of TC in EF system. The self-doped defects and graphite-nitrogen in d-NPC improved the oxygen reduction performance and increased the H2O2 yield, while pyridine nitrogen could catalyze H2O2 to generate ·OH. The possible pathway of TC degradation was also proposed. In this study, defective carbon materials were prepared by ball milling, which provided a new strategy for efficient in-situ H2O2 production and the degradation of pollutants.

In vivo evaluation of focused ultrasound ablation surgery (FUAS)-induced coagulation using echo amplitudes of the therapeutic focused ultrasound transducer.

OBJECTIVE: Monitoring sensitivity of sonography in focused ultrasound ablation surgery (FUAS) is limited (no hyperechoes in ∼50% of successful coagulation in uterine fibroids). A more accurate and sensitive approach is required. METHOD: The echo amplitudes of the focused ultrasound (FUS) transducer in a testing mode (short pulse duration and low power) were found to correlate with the ex vivo coagulation. To further evaluate its coagulation prediction capabilities, in vivo experiments were carried out. The liver, kidney, and leg muscles of three adult goats were treated using clinical FUAS settings, and the echo amplitude of the FUS transducer and grayscale in sonography before and after FUAS were collected. On day 7, animals were sacrificed humanely, and the treated tissues were dissected to expose the lesion. Echo amplitude changes and lesion areas were analyzed statistically, as were the coagulation prediction metrics. RESULTS: The echo amplitude changes of the FUS transducer correlate well with the lesion areas in the liver (R = 0.682). Its prediction in accuracy (94.4% vs. 50%), sensitivity (92.9% vs. 35.7%), and negative prediction (80% vs. 30.8%) is better than sonography, but similar in specificity (80% vs. 100%) and positive prediction (100% vs. 100%). In addition, the correlation between tissue depth and the lesion area is not good (|R| < 0.2). Prediction performances in kidney and leg muscles are similar. CONCLUSION: The FUS echo amplitudes are sensitive to the tissue properties and their changes after FUAS. They are sensitive and reliable in evaluating and predicting FUAS outcomes.

Bimetallic iron-nickel phosphide as efficient peroxymonosulfate activator for tetracycline hydrochloride degradation: Performance and mechanism.

Sulfate radical-based advanced oxidation processes with (SR-AOPs) are widely employed to degrade organic pollutants due to their high efficiency, cost-effectiveness and safety. In this study, a highly active and stable FeNiP was successfully prepared by reduction and heat treatment. FeNiP exhibited high performance of peroxymonosulfate (PMS) activation for tetracycline hydrochloride (TC) removal. Over a wide pH range, an impressive TC degaradation efficiency 97.86% was achieved within 60 min employing 0.1 g/L FeNiP and 0.2 g/L PMS at room temperature. Both free radicals of SO4·-, ·OH, ·O2- and non-free radicals of 1O2 participated the TC degradation in the FeNiP/PMS system. The PMS activation ability was greatly enhanced by the cycling between Ni and Fe bimetal, and the active site regeneration was achieved due to the existence of the negatively charged Pn-. Moreover, the FeNiP/PMS system exhibited substantial TC degradation levels in both simulated real-world disturbance scenarios and practical water tests. Cycling experiments further affirmed the robust stability of FeNiP catalyst, demonstrating sustained degradation efficiency of approximately 80% even after four cycles. These findings illuminate its promising potential across natural water bodies, presenting an innovative catalyst construction approach for PMS activation in the degradation of antibiotic pollutants.

Ultra-high flux mesh membranes coated with tannic acid-ZIF-8@MXene composites for efficient oil-water separation.

Oil/water separation has become a global concern due to the increasing discharge of multi-component harmful oily wastewater. Super wetting membranes have been shown to be an effective material for oil/water separation. Ultra-high flux stainless-steel meshes (SSM) with superhydrophilicity and underwater superoleophobicity were fabricated by tannic acid (TA) modified ZIF-8 nanoparticles (TZIF-8) and two-dimensional MXene materials for oil/water separation. The TZIF-8 increased the interlayer space of MXene, enhancing the flux permeation (69,093 L m-2h-1) and rejection of the composite membrane (TZIF-8@MXene/SSM). The TZIF-8@MXene/SSM membrane showed an underwater oil contact angle of 154.2°. The membrane maintained underwater superoleophobic after stability and durability tests, including various pH solutions, organic solvents, reusability, etc. In addition, the oil/water separation efficiency of TZIF-8@MXene/SSM membranes was higher than 99% after treatment in harsh conditions and recycling. The outstanding anti-fouling, stability, durability, and recyclability properties of TZIF-8@MXene/SSM membrane highlight the remarkable potential of membranes for complex oil/water separation process.

High-throughput single-cell assay for precise measurement of the intrinsic mechanical properties and shape characteristics of red blood cells.

The intrinsic physical and mechanical properties of red blood cells (RBCs), including their geometric and rheological characteristics, can undergo changes in various circulatory and metabolic diseases. However, clinical diagnosis using RBC biophysical phenotypes remains impractical due to the unique biconcave shape, remarkable deformability, and high heterogeneity within different subpopulations. Here, we combine the hydrodynamic mechanisms of fluid-cell interactions in micro circular tubes with a machine learning method to develop a relatively high-throughput microfluidic technology that can accurately measure the shear modulus of the membrane, viscosity, surface area, and volume of individual RBCs. The present method can detect the subtle changes of mechanical properties in various RBC components at continuum scales in response to different doses of cytoskeletal drugs. We also investigate the correlation between glycosylated hemoglobin and RBC mechanical properties. Our study develops a methodology that combines microfluidic technology and machine learning to explore the material properties of cells based on fluid-cell interactions. This approach holds promise in offering novel label-free single-cell-assay-based biophysical markers for RBCs, thereby enhancing the potential for more robust disease diagnosis.

KIF2C promotes clear cell renal cell carcinoma progression via activating JAK2/STAT3 signaling pathway.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) is one of the most common malignant tumors that can be highly aggressive. Despite advances in the exploration of its underlying molecular biology, the clinical outcome for advanced ccRCC is still unsatisfied. Recently, more attention was paid to the functions of Kinesin family member 2C (KIF2C) in cancer progression, while the specific function of KIF2C in ccRCC has not been sufficiently elucidated. The present study aims to investigate the role of KIF2C in the progression of ccRCC and reveal potential mechanisms. METHODS: Expression of KIF2C in ccRCC tissues and adjacent normal tissue was compared and the association of KIF2C expression level with tumor grade, stage, and metastasis were analyzed using online web tool. Kaplan-Meier survival was performed to detect the association of KIF2C expression and patient' prognosis. Stably cell lines with KIF2C knockdown or overexpression were constructed by lentivirus infection. CCK-8, colony formation, scratch healing, and transwell invasion assays were carried out to explore the effect of KIF2C knockdown or overexpression on the proliferation, migration, and invasion of ccRCC cells. Gene set enrichment analysis (GSEA) was conducted to reveal signaling pathways associated with KIF2C expression. The effect of KIF2C on JAK2/STAT3 signaling pathway were explored by western blot assay. RESULTS: KIF2C expression was significantly upregulated in ccRCC tissues and was higher with the increase of tumor grade, stage, and metastasis. Higher expression of KIF2C was correlated with worse overall survival and diseases free survival in ccRCC patients. Silence of KIF2C inhibited proliferation, migration, and invasion in ccRCC cells. Conversely, overexpression of KIF2C had the opposite effect. GSEA results showed that JAK/STAT signaling pathway was markedly enriched in KIF2Chigh group. Pearson' correlation revealed that KIF2C expression was significantly associated with genes in JAK2/STAT3 signaling. Western blot results showed that KIF2C knockdown decreased protein expression of p-JAK2 and p-STAT3, and KIF2C overexpression increased the phosphorylation of JAK2 and STAT3. AG490, a JAK2/STAT3 signaling inhibitor, could partly impair the tumor-promoting effects of KIF2C in ccRCC. CONCLUSION: KIF2C expression was significantly upregulated in ccRCC and correlated with tumor grade, stage, metastasis, and patients' prognosis. KIF2C promoted ccRCC progression via activating JAK2/STAT3 signaling pathway, and KIF2C might be a novel target in ccRCC therapy.

Mechanosensitive accumulation of non-muscle myosin IIB during mitosis requires its translocation activity.

Non-muscle myosin II (NMII) is a force-generating mechanosensitive enzyme that responds to mechanical forces. NMIIs mechanoaccumulate at the cell cortex in response to mechanical forces. It is essential for cells to mechanically adapt to the physical environment, failure of which results in mitotic defects when dividing in confined environment. Much less is known about how NMII mechanoaccumulation is regulated during mitosis. We show that mitotic cells respond to compressive stress by promoting accumulation of active RhoA at the cell cortex as in interphase cells. RhoA mechanoresponse during mitosis activates and stabilizes NMIIB via ROCK signaling, leading to NMIIB mechanoaccumulation at the cell cortex. Using disease-related myosin II mutations, we found that NMIIB mechanoaccumulation requires its motor activity that translocates actin filaments, but not just its actin-binding function. Thus, the motor activity coordinates structural movement and nucleotide state changes to fine-tune actin-binding affinity optimal for NMIIs to generate and respond to forces.

Enhanced conversion of superoxide radical to singlet oxygen in peroxymonosulfate activation by metal-organic frameworks derived heteroatoms dual-doped porous carbon catalyst.

The activation of persulfate technology using carbon-based materials doped with heteroatoms has been extensively researched for the elimination of refractory pollutants in wastewater. In this study, metal-organic frameworks were utilized as precursors to synthesize P, N dual-doped carbon material (PNC), which was employed to activate peroxymonosulfate (PMS) for the degradation of tetracycline hydrochloride (TCH). The results demonstrated a 90.2% removal efficiency of total organic carbon within 60 min. The significant increase of surface defects on the nitrogen self-doped porous carbon materials anchored with phosphorus promoted the conversion of superoxide radical to singlet oxygen during PMS activation, which was identified as the key active species of PNC/PMS system. Additionally, the enhanced direct electron transfer also facilitated the degradation of TCH. Consequently, TCH was successfully degraded into nontoxic and harmless inorganic small molecules. The findings of this research provide valuable insights into improving the performance of heteroatom-doped carbon materials for pollutant degradation by activating PMS and transforming the non-radical pathway. The results highlight the potential of metal-organic frameworks derived heteroatoms dual-doped porous carbon catalysts for the development of advanced treatment technologies in wastewater treatment.

Evolution of surface area and membrane shear modulus of matured human red blood cells during mechanical fatigue.

Mechanical properties of red blood cells (RBCs) change during their senescence which supports numerous physiological or pathological processes in circulatory systems by providing crucial cellular mechanical environments of hemodynamics. However, quantitative studies on the aging and variations of RBC properties are largely lacking. Herein, we investigate morphological changes, softening or stiffening of single RBCs during aging using an in vitro mechanical fatigue model. Using a microfluidic system with microtubes, RBCs are repeatedly subjected to stretch and relaxation as they squeeze into and out of a sudden contraction region. Geometric parameters and mechanical properties of healthy human RBCs are characterized systematically upon each mechanical loading cycle. Our experimental results identify three typical shape transformations of RBCs during mechanical fatigue, which are all strongly associated with the loss of surface area. We constructed mathematical models for the evolution of surface area and membrane shear modulus of single RBCs during mechanical fatigue, and quantitatively developed an ensemble parameter to evaluate the aging status of RBCs. This study provides not only a novel in vitro fatigue model for investigating the mechanical behavior of RBCs, but also an index closely related to the age and inherent physical properties for a quantitative differentiation of individual RBCs.

Effects of Accelerated Aging on Thermal, Mechanical and Shape Memory Properties of Cyanate-Based Shape Memory Polymer: III Vacuum Thermal Cycling.

Shape memory polymers (SMPs) with intelligent deformability have shown great potential in the field of aerospace, and the research on their adaptability to space environments has far-reaching significance. Chemically cross-linked cyanate-based SMPs (SMCR) with excellent resistance to vacuum thermal cycling were obtained by adding polyethylene glycol (PEG) with linear polymer chains to the cyanate cross-linked network. The low reactivity of PEG overcame the shortcomings of high brittleness and poor deformability while endowing cyanate resin with excellent shape memory properties. The SMCR with a glass transition temperature of 205.8 °C exhibited good stability after vacuum thermal cycling. The SMCR maintained a stable morphology and chemical composition after repeated high-low temperature cycle treatments. The SMCR matrix was purified by vacuum thermal cycling, which resulted in an increase in its initial thermal decomposition temperature by 10-17 °C. The continuous vacuum high and low temperature relaxation of the vacuum thermal cycling increased the cross-linking degree of the SMCR, which improved the mechanical properties and thermodynamic properties of SMCR: the tensile strength of SMCR was increased by about 14.5%, the average elastic modulus was greater than 1.83 GPa, and the glass transition temperature increased by 5-10 °C. Furthermore, the shape memory properties of SMCR after vacuum thermal cycling treatment were well maintained due to the stable triazine ring formed by the cross-linking of cyanate resin. This revealed that our developed SMCR had good resistance to vacuum thermal cycling and thus may be a good candidate for aerospace engineering.

Effect of neoadjuvant endocrine therapy on the acoustic environment in tissue of prostate cancer: a study of histopathological characteristics.

Background: Neoadjuvant endocrine therapy (NET) of prostate cancer (PCa) may alter the tissue acoustic environment (AET). The structure of tissue is an important factor affecting AET. The aim is to analyze changes in tissue structures after NET in PCa, focusing on calcifications, smooth muscle cells, and blood vessels. Methods: We collected 40 patients diagnosed with PCa by pathological examination between October 2020 and December 2022. Twenty patients who underwent radical prostatectomy (RP) after NET were designed as the test group. Twenty patients without NET were assigned to the control group. Calcifications, smooth muscle cells and blood vessels were observed by hematoxylin-eosin (HE) staining and Van Gieson (VG)-special staining respectively. Then the amount and acreage of calcified tissue, the number of smooth muscle cells and different types of blood vessels were quantitatively analyzed. Results: There was a subtle increase in the number (P=0.001) and the area (P<0.001) of calcification after NET. The total number of smooth muscle cells was significantly higher than that without NET (P<0.001). NET resulted in significantly fewer veins compared to those without NET (P<0.001). There was a little increase in the number of arteries after NET (P=0.001). The number of veins decreased was much greater than the number of arteries increased resulting in significantly fewer total vessels after NET (P<0.001). Conclusions: NET can lead to changes in calcifications, smooth muscle cells, and blood vessels within PCa tissues, which may cause alterations in AET.

A Metal Coordination-Based Supramolecular Elastomer with Shape Memory-Assisted Self-Healing Effect.

Rubber materials are widely used in aerospace, automotive, smart devices and artificial skin. It is significant to address the aging susceptibility of conventional vulcanized rubber and to impart it rapid self-healing performance for destructive crack damage. Herein, a novel supramolecular rubber elastomer is prepared by introducing metal coordination between carboxyl-terminated polybutadiene and polystyrene-vinylpyridine copolymer. Based on the metal coordination interaction, the elastomer exhibits shape memory and self-healing properties. Moreover, a rapid closure-repair process of destructive cracks is achieved by presetting temporary shapes. This shape memory-assisted self-repair model is shown to be an effective means for rapid repair of severe cracks. An approach to enhance the mechanical and self-healing properties of elastomer was demonstrated by adding appropriate amounts of oxidized carbon nano-onions (O-CNO) into the system. The tensile strength of the elastomer with an O-CNOs content of 0.5 wt% was restored to 83 ± 10% of the original sample after being repaired at 85 °C for 6 h. This study confirms that metal coordination interaction is an effective method for designing shape memory self-healing rubber elastomer. The shape memory-assisted self-healing effect provides a reference for the rapid self-repairing of severe cracks.

High-Intensity Focused Ultrasound in Interventricular Septal Myocardial Ablation.

High-intensity focused ultrasound (HIFU) can cause necrotic damage in deep tissues through thermal ablation and cavitation, without significant damage to the surrounding tissues. High blood perfusion of heart affects the energy deposition. This study aimed to evaluate the effect of cooling of coronary blood flow for HIFU ablation.Continuous and pulsed HIFU (2000 J) at duty cycles of 100% and 25% were examined for their capacity to ablate the perfused porcine heart tissue in vitro. After ablation, grayscale changes and pathological features were observed or measured, and the area and volume of tissue necrosis were calculated.The cardiomyocytes in the lesions underwent necrosis with a clear boundary. The endocardial surface was intact without necrosis. The three-dimensional morphology of the lesions appeared approximately as ellipsoids. With the increase in perfusion speed, the necrotic volume in the target area was gradually reduced.HIFU has the potential to become a new minimally invasive surgery for ventricular septal myocardial ablation. Reduction of coronary blood flow can improve the ablation effect.

3D Zero Poisson's Ratio Honeycomb Structure for Morphing Wing Applications.

Such as flying creatures, morphing aircraft can expand their aerodynamic flight envelopes by changing aerodynamic shapes, significantly improving the scope of application and flight efficiency. A novel 3D Zero Poisson's Ratio (ZPR) honeycomb structure is designed to meet the flexible deformation requirements of morphing aircraft. The 3D ZPR honeycomb can deform in the three principal directions with smooth borders and isotropic. Analytical models related to the uniaxial and shear stiffnesses are derived using the Timoshenko beam model and validated using the quasi-static compression test. The Poisson's ratio of the 3D ZPR honeycomb structure has an average value of 0.0038, proving the feasibility of the 3D ZPR concept. Some pneumatic muscle fibers are introduced into the system as flexible actuators to drive the active deformation of the 3D ZPR honeycomb. The active 3D ZPR honeycomb can contract by 14.4%, unidirectionally bend by 7.8°, and multi-directions bend under 0.4 Mpa pressure. Both ZPR properties and flexible morphing capabilities show the potential of this novel 3D ZPR configuration for morphing wings.

Numerical simulation of flow characteristics in a permeable liver sinusoid with leukocytes.

Double-layered channels of sinusoid lumen and Disse space separated by fenestrated liver sinusoidal endothelial cells (LSECs) endow the unique mechanical environment of the liver sinusoid network, which further guarantees its biological function. It is also known that this mechanical environment changes dramatically under liver fibrosis and cirrhosis, including the reduced plasma penetration and metabolite exchange between the two flow channels and the reduced Disse space deformability. The squeezing of leukocytes through narrow sinusoid lumen also affects the mechanical environment of liver sinusoid. To date, the detailed flow-field profile of liver sinusoid is still far from clear due to experimental limitations. It also remains elusive whether and how the varied physical properties of the pathological liver sinusoid regulate the fluid flow characteristics. Here a numerical model based on the immersed boundary method was established, and the effects of Disse space and leukocyte elasticities, endothelium permeability, and sinusoidal stenosis degree on fluid flow as well as leukocyte trafficking were specified upon a mimic liver sinusoid structure. Results showed that endothelium permeability dominantly controlled the plasma penetration velocity across the endothelium, whereas leukocyte squeezing promoted local penetration and significantly regulated wall shear stress on hepatocytes, which was strongly related to the Disse space and leukocyte deformability. Permeability and elasticity cooperatively regulated the process of leukocytes trafficking through the liver sinusoid, especially for stiffer leukocytes. This study will offer new insights into deeper understanding of the elaborate mechanical features of liver sinusoid and corresponding biological function.

Impact Response of the Honeycomb Sandwich Structure with Different Poisson's Ratios.

The honeycomb sandwich structure is widely used in energy-absorbing facilities because it is lightweight, has a high specific stiffness and high specific strength, and is easy to process. It also has dynamic mechanical characteristics such as a high impact resistance and high energy absorption. To explore the influence of the Poisson's ratio on the local impact resistance, this paper compares and analyzes the local impact resistance of a series of honeycomb cores with different Poisson's ratios under the impact of a spherical projectile at different speeds. Three typical honeycombs with negative/zero/positive Poisson ratios (re-entrant hexagon, semi-re-entrant hexagon, and hexagon) are selected to change the geometric parameters in order to have the same relative density and different Poisson ratios (−2.76−3.63). The relative magnitude of the rear face sheet displacement is in the order of negative Poisson's ratio > zero Poisson's ratio > positive Poisson's ratio, which reveals that the honeycomb structure with the positive Poisson's ratio has better protection ability than the others. Finally, a dual-wall hexagonal honeycomb is proposed. The rear face sheet displacement of the dual-wall hexagonal honeycomb sandwich structure is reduced by 34.4% at 25 m/s compared with the hexagonal honeycomb, which has a better local impact resistance.