Cushion Method Research Articles

Enhancing static load test of pipe pile composite foundation with innovative elastic cushioning technology

Pipe piles have been widely used in composite foundation treatment by virtue of the advantages of assembly line production, easy control of pile quality, fast construction, high bearing capacity of single pile and green environmental protection. By introducing elastic cushion in the static load test method of pipe pile composite foundation, and using theoretical analysis and field test to study the change rule of settlement, pile-soil stress ratio and pile top stress of pipe pile composite foundation with different cushion stiffness. It is concluded that it is feasible to replace the sand cushion layer recommended by the current specification with elastic cushion layer. The study shows that the elastic cushion method of static load test of pipe pile composite foundation is closer to the bearing state of real working condition. The elastic cushion has better pile-soil stress adjustment effect, which is more responsive to the stress adjustment effect of actual engineering cushion, and the elastic cushion provides an improved method for the static load test method of composite foundation.

Gene knockdown in HaCaT cells by small interfering RNAs entrapped in grapefruit-derived extracellular vesicles using a microfluidic device

Small interfering RNAs (siRNAs) knockdown the expression of target genes by causing mRNA degradation and are a promising therapeutic modality. In clinical practice, lipid nanoparticles (LNPs) are used to deliver RNAs, such as siRNA and mRNA, into cells. However, these artificial nanoparticles are toxic and immunogenic. Thus, we focused on extracellular vesicles (EVs), natural drug delivery systems, for the delivery of nucleic acids. EVs deliver RNAs and proteins to specific tissues to regulate various physiological phenomena in vivo. Here, we propose a novel method for the preparation siRNAs encapsulated in EVs using a microfluidic device (MD). MDs can be used to generate nanoparticles, such as LNPs, by controlling flow rate to the device, but the loading of siRNAs into EVs using MDs has not been reported previously. In this study, we demonstrated a method for loading siRNAs into grapefruit-derived EVs (GEVs), which have gained attention in recent years for being plant-derived EVs developed using an MD. GEVs were collected from grapefruit juice using the one-step sucrose cushion method, and then GEVs-siRNA-GEVs were prepared using an MD device. The morphology of GEVs and siRNA-GEVs was observed using a cryogenic transmission electron microscope. Cellular uptake and intracellular trafficking of GEVs or siRNA-GEVs to human keratinocytes were evaluated by microscopy using HaCaT cells. The prepared siRNA-GEVs encapsulated 11% of siRNAs. Moreover, intracellular delivery of siRNA and gene suppression effects in HaCaT cells were achieved using these siRNA-GEVs. Our findings suggested that MDs can be used to prepare siRNA-EV formulations.

Preparation, Purification and Performance Evaluation of Polyclonal Antibody Against SARS-CoV-2 Produced in Rat.

Among all known human coronaviruses, some viruses (e.g., SARS-CoV-2) cause severe pneumonia or even death. With the regard to its spread and the importance of its rapid identification/treatment, and because pAbs are relatively cheap, able to bind to more sites on antigens and even neutralize them, this study was done for the production and purification of anti-SARS-CoV-2 polyclonal antibodies (pAb) in rats. Viral antigen purification was performed by PEG/NaCl precipitation. The efficiency of the sucrose cushion method was also investigated to produce a purer antigen. Immunization was done and antibody purification was performed by ammonium sulfate precipitation (33%), dialysis, and ion-exchange chromatography. Western blotting and enzyme-linked immunosorbent assay (ELISA) were performed to verify the antibody specificity. All data were analyzed by SPSS software. The results showed that the amount of concentrated virus increased with the increase of PEG concentration. Moreover, the sucrose cushion method increased its purity. Besides, induction of immune response in rats for pAb production with high titers was reached via these antigens and ELISA/western blot results indicated a suitable antibody-antigen interaction. Additionally, it was shown that ion-exchange chromatography could be a suitable technique for IgG purification. Herein, we presented a simple and cheap method for the purification of whole viral particles with relatively high quality. The results verified that these antigens could elicit a good immune response in the rat. The obtained pAbs showed a good specificity toward SARS-CoV-2 antigens. Accordingly, this study proposes a promising method for viral vaccine development.

VARTM process of composites using double-bag air cushion method

This article introduced the double-bag air cushion method (DBACM) as an economical and efficient manufacturing process of polymer composites associated with the vacuum-assisted resin transfer molding (VARTM) process. The method utilizes an improved double-bag along with several air cushions to create distribution channels for enhancing the resin flow during infusion. Experimental evaluation on resin infusion behavior and mechanical properties, including ultimate strength, void content, surface finish, and thickness uniformity, is performed for composites reinforced with both jute fibers and glass fibers. Results showed that the DBACM reduces the infusion time by more than 26.0% as compared with traditional VARTM. The difference in ultimate strength of the part between the DBACM and the VARTM is about 2.9%–3.9%. The void content of the E-glass composites is 1.3%–1.5% due to the few fissure-like microvoids, whereas the void content of the jute composites is high, about 2.4%–4.0%, because of the sparse spherical macrovoids. Additionally, there are no major differences in surface finish and thickness uniformity between the parts fabricated by DBACM and by conventional VARTM.

A More Accessible, Time-Saving, and Efficient Method for In Vitro Plant Regeneration from Potato Protoplasts.

Both obtaining high-yielding, viable protoplasts and following reliable regeneration protocols are prerequisites for the continuous expansion and development of newly emerging systems involving protoplast utilization. This study determines an efficient process from protoplast isolation to shoot regeneration in vitro. The maximum yield of protoplast extraction, which was 6.36 ± 0.51 × 106 protoplasts/g fresh weight (FW), was approximately 3.7 times higher than that previously reported for potato protoplasts. To obtain data, wounded leaves were used by partially cutting both sides of the midrib, and isolated protoplasts were purified by the sucrose cushion method, with a sucrose concentration of 20%. We confirmed a significant effect on the extraction efficiency by measuring enzymolysis during a 6 h period, with three times more washing buffer than the amount normally used. Protoplasts fixed in alginate lenses with appropriate space were successfully recovered and developed into microcalli 2 weeks after culture. In addition, to induce high efficiency regeneration from protoplasts, calli in which greening occurred for 6 weeks were induced to develop shoots in regeneration medium solidified by Gelrite, and they presented a high regeneration efficiency of 86.24 ± 11.76%.

Analysis of Monitoring in Displacement For Vacuum Combined Stack Preloading about Soft foundation Sluice

Soft soil foundation treatment methods mainly include soil replacement cushion method, dynamic compaction method, drainage consolidation method, etc. Drainage consolidation methods mainly include: vacuum preloading method, stack preloading method and vacuum combined stacking preloading method. Among them, the vacuum preloading method has obvious advantages in treating large areas and deep soft foundations. This paper describes the process of soft soil foundation vacuum combined with stack preloading reinforcement. Through the monitoring of the vacuum preloading process, we mainly analyzed the monitoring results and development trend of horizontal displacement.

Exosomes Released by Gastric Cancer Cells Induce Transition of Pericytes Into Cancer-Associated Fibroblasts.

BackgroundCancer-associated fibroblasts (CAFs) are functionally and structurally essential for tumor progression. There are 3 main origins of CAFs: mesenchymal stem cells (MSCs), epithelial-to-mesenchymal (EMT) transition cells, and tissue-resident cells. Pericytes retain characteristics of progenitor cells and can differentiate into other cells under normal physiological conditions and into myofibroblasts under pathological conditions. Exosomes play an important role in intercellular communication by transferring membrane components and nucleic acids between different cells. In this study, we evaluated whether cancer cell-derived exosomes are involved in regulating the transition of pericytes to CAFs.Material/MethodsExosomes from GES-1 and SGC7901 cells were isolated by serial centrifugation and purified from the supernatant by the 30% sucrose/D2O cushion method. A transmission electron microscope was used to observe exosome morphologies, and nanoparticle tracking analysis was used to analyze size distribution of exosomes. Western blot analysis, immunofluorescent staining, and qPCR were employed to detect CAFs marker expression and signaling pathways involved in CAFs transition.ResultsGastric cancer cell-derived exosomes enhanced pericytes proliferation and migration and induced the expression of CAFs marker in pericytes. We then demonstrated that the PI3K/AKT and MEK/ERK pathways were activated by tumor-derived exosomes, and BMP pathway inhibition reverses cancer exosomes-induced CAFs transition.ConclusionsOur results suggest that gastric cancer cells induce the transition of pericytes to CAFs by exosomes-mediated BMP transfer and PI3K/AKT and MEK/ERK pathway activation, and suggest that pericytes may be an important source of CAFs.

The Cushion Method: A New Technique for the Recovery of Hydrophilic Nanocarriers.

Microencapsulation of hydrophilic therapeutic agents such as proteins or nucleotides into a nanocarrier is frequently accomplished in inverse (water-in-oil) emulsions. However, the redispersion of the nanocarriers in aqueous media often involves a complicated purification process, and the redispersion usually requires additional surfactants for its colloidal stability, which is not favored for biological applications. We propose a simple, fast, and mild method to recover hydrophilic nanocarriers prepared in inverse emulsions by temporary coating of the nanocarriers with biocompatible small molecules, so that the final aqueous dispersion of the nanocarriers can be dispersed with high recovery rate, minimal aggregation, and no additional surfactants. Such a method is termed the "cushion method" and was adopted in the preparation of chitosan nanocarriers. The nanocarriers recovered with the cushion method release encapsulated peptides in a pH-responsive manner and do not require surfactants for colloidal stabilization.

OR16 Antibodies to donor human leukocyte antigen induce exosomes containing tissue-restricted self-antigens in acute and chronic rejection

Aim Immune responses to tissue-restricted self-antigens (SAgs) are known contributors to acute and chronic rejection in solid organ transplantation (Tx). The goal of this study was to determine whether a donor-specific antibody (DSA) induces exosomes during lung and kidney allograft rejection and to define its antigenic compositions. Methods Exosomes were isolated from sera and bronchoalveolar lavage (BAL) of lung Tx recipients with acute or chronic rejection who developed both DSA and antibodies to SAgs, and from sera of kidney Tx recipients with transplant glomerulopathy (TG) who developed both DSA and antibodies to kidney-associated SAgs. The exosomes were isolated by ultracentrifugation, and then purified by the sucrose cushion method. Expression of lung-associated SAgs Collagen-V and K α 1-tubulin was examined by immunogold labelling and visualized by transmission electron microscopy. The presence of lung-associated SAgs and kidney-associated SAgs (i.e., Collagen-IV, fibronectin), and exosome-specific marker annexin-V was detected by Western immunoblot. Results Exosomes isolated from patients with acute rejection, chronic rejection, and TG showed the presence of tissue-restricted SAgs. Lung-associated SAgs Collagen-V and K α 1-tubulin were confirmed on the surface of exosomes. Exosomes with Collagen-V were detectable in exosomes isolated from sera just 1 month after lung Tx in all patients with acute rejection, much earlier than it could be diagnosed clinically (i.e., 3 months). Similarly, exosomes from sera in patients with bronchiolitis obliterans syndrome contained Collagen-V 6 months after lung Tx, before clinical diagnosis was possible. Exosomes from patients with TG had significantly higher expression of kidney-associated SAgs compared with the stable group. Conclusions The exosomes isolated from lung Tx recipients with acute and chronic rejection who developed DSA and antibodies to lung-associated SAgs and from kidney Tx recipients with TG confirm the presence of tissue-restricted SAgs in these patients, while the respective stable control groups do not. We therefore conclude that antibodies to human leukocyte antigen after lung or kidney Tx induce exosomes containing SAgs, which may result in the spread of immune response to tissue-restricted SAgs. T. Mohanakumar: Grant/Research Support; Company/Organization ; NIH R21AI123034 .

Experimental analysis of resin infusion in air cushion method

Abstract A new technique of resin infusion, called the air cushion method (ACM), has been developed to improve infusion time associated with the vacuum assisted resin transfer molding (VARTM) process. The method utilizes an innovative vacuum bag consisting of a bagging film and air cushions. After the preform is sealed by the bagging film and then evacuated, distribution channels are created between air cushions for flow enhancement during infusion. Once the required volume of resin is infused, the bonding interfaces between the air cushion and the bagging film are punctured and distribution channels collapse. The ambient pressure is applied on the bagging film that entirely compacts the preform. This paper investigates the infusion process in ACM using flow visualization experiments. An approximate estimation of the equivalent permeability of the bulk distribution channel is provided. Finally, an assessment of the properties of the ACM part is performed in comparison with VARTM part.

Effect of exosome isolation methods on physicochemical properties of exosomes and clearance of exosomes from the blood circulation

Exosomes, which are expected to be delivery systems for biomolecules such as nucleic acids, are collected by several methods. However, the effect of exosome isolation methods on the characteristics of exosomes as drug carriers, such as recovery efficiency after sterile filtration and pharmacokinetics, has not been investigated despite the importance of these characteristics for the development of exosome-based delivery systems. In the present study, exosomes collected from murine melanoma B16-BL6 cells by several methods were compared with respect to dispersibility, recovery rate after filtering, and clearance from the blood circulation in mice. The exosomes were collected by three ultracentrifugation-based methods: simple ultracentrifugation/pelleting (pelleting method), ultracentrifugation with an iodixanol cushion (cushion method), and ultracentrifugation on an iodixanol density gradient (gradient method). The isolation methods had little effect on the particle number of exosomes. In contrast, transmission electron microscopy observation and size distribution measurement using tunable resistive pulse sensing indicated that the exosomes of the gradient method were more dispersed than the others. The exosomes were labeled with Gaussia luciferase and intravenously injected into mice. Clearance of injected exosomes from the blood circulation did not significantly change with isolation methods. When the exosomes were filtered using a 0.2-μm filter, the recovery rate was 82% for the exosomes of the gradient method, whereas it was less than 50% for the others. These results indicate that the exosome isolation method markedly affects the dispersibility and filtration efficiency of the exosomes.

Research on the Ideal Cushion Method of Pneumatic Cylinder

In the situation of high-speed or heavy load, pneumatic cylinders usually generate cushion failure like collision or rebound, so that the key question to be solved for the cylinders is cushion. In order to obtain a better cushion method, the paper used the ideal cushion characteristic curve of hydraulic cylinders for reference; and throttling area equation, temperature equation, flow rate equation and motion equation were established. By building the simulation module in Matlab/Simulink, the rule of throttling area approaching to the ideal cushion curve was found, which provide theoretical basis for the design of cylinders cushion devices.

Effect of process parameters on the surface quality of air cushion method

A new method of the vacuum-assisted resin transfer molding process, called air cushion method, has been developed to manufacture composite parts. The process utilizes additional air cushions bound into the bagging film beneath. After the preform is sealed by the bag and evacuated, distribution channels are created between air cushions to enhance resin flow during infusion. Once the resin infusion is completed, the binding interfaces between the air cushion and the bagging film are cut and distribution channels collapse. The vacuum bag entirely compacts the preform. The goal of this study is to utilize a 24 full factorial design to evaluate the effects of process variables, including the number of the air cushion (factor A), thickness of the air cushion (factor B), elasticity of the bagging film (factor C), and vacuum pressure in the cavity (factor D), on the surface quality of air cushion method components. Results show that the process parameters ranked in decreasing order of importance are B, D, A, and C for affecting the surface height difference. Compared with traditional vacuum-assisted resin transfer molding, air cushion method at the optimum settings reduces the infusion time by 68.4% but increases the surface height difference by 0.0312 mm.

The Structural Design and Experimental Research of Multi-Level Cushioning Packaging Storage Box

Aiming at the damage of package caused by emergency rescue and other severe transportation environment, a multi-level cushioning packaging storage box is proposed in this paper, the precise instrument is fixed in the box, which achieves the box-instrument integration. At the moment when air-dropped box touches the ground, the impact force is absorbed and cushioned through plastic cork base, rubber absorber, box body, steel wire rope spring, hydraulic damper for five times, which could provide effective cushion protection for the precise instrument which fragility value is not less than 15G. Simulation airdrop tests are performed to the storage box with different cushion levels, and the test shows that the result of five-level cushion method proposed in the paper is the best, and overload values are all within 12G, which could provide enough cushion space for precise instrument to avoid touchdown damage.

The Selection of the Collapsible Loess Foundation Treatment Methods

The collapsible loess ground treatment methods include dynamic compaction, soil replacement cushion method, lime-soil compaction pile composite foundation, pile foundation, etc. Each method has its advantages and disadvantages. The bearing capacity of collapsible loess is not lower, it is non-soft soil. The purpose of the collapsible loess ground treatment is to eliminate the collapsible at the most, few to increase the capacity and improve the heterogeneity of the foundation. In this paper, the collapsible loess foundation treatment methods are been compacted from the technical and economic factors. And the key issues of the collapsible loess ground treatment methods are discussed.

Cracking Mechanism of Long Concrete Bedding Cushion and Prevention Method

The long concrete bedding cushions are more vulnerable to cracking than the dam concrete, even the cushion is much shorter than the dam block, especially those constructed in hot season and the off period lasts long. The cracking mechanism of such cushion is studied and presented in this paper. There are several reasons contribute to the cracks of bedding cushion, but the thermal stress is the main factor. The temperature distribution is always unevenly during the construction period of bedding cushion. During the long off period, temperature drop in local high temperature zone, temperature fluctuation and temperature difference between inside and surface are the main factors causing cracks for bedding cushion without proper thermal control measures. Some thermal control measures are always used in practical engineering, but it can not always effectively prevent bedding cushion from cracking. Reasonable water pipes cooling measure, which can prevent local high temperature at the early age of construction, and effective heat preservation measures in cold season, which can reduce temperature difference between inside and surface and temperature fluctuation, are necessary to prevent cracking. One bedding cushion of concrete dam is numerically stimulated by 3D FEM, and effective temperature control measure is proposed in this paper.

308 エアクッション方式による自動車搬送用パレットの開発に関する研究(流体工学(2))

308 エアクッション方式による自動車搬送用パレットの開発に関する研究(流体工学(2))

Reducing differential settlements of approach embankments

This paper presents a case history of an approach road remediation project on a low embankment over soft Ariake clay, located in the coastal Saga Plain of Japan. After the road had been opened to traffic for two-and-a-half years, large settlements were observed, and there was significant differential settlement between piled structures and approach road embankments on soft clay. This differential settlement had a significant impact on vehicle ride quality, and necessitated a remediation programme. In the remediation project, a new method called the column approach (CA) method was adopted to support a transitional zone at the interfaces of piled structures and road embankment. With the CA method a transitional zone was designed at these interfaces to be supported by soil-cement columns of varying lengths to smooth out the settlement profile within these zones. Field monitoring was conducted following completion of remediation. The CA method was also compared with two other Japanese code-designated methods: overlaying a new pavement on the existing pavement at a certain time interval, and constructing a concrete cushion slab under the road pavement. Both practical and economic aspects are examined in the case study presented. This study shows that, when the differential settlement is over 0·3 m, overlay remediation is not economic, and the approach cushion method does not perform well. The CA method not only reduces the differential settlement effectively, but also reduces the total construction cost, although the initial investment is relatively high.

Reducing differential settlements of approach embankments

This paper presents a case history of an approach road remediation project on a low embankment over soft Ariake clay, located in the coastal Saga Plain of Japan. After the road had been opened to traffic for two-and-a-half years, large settlements were observed, and there was significant differential settlement between piled structures and approach road embankments on soft clay. This differential settlement had a significant impact on vehicle ride quality, and necessitated a remediation programme. In the remediation project, a new method called the column approach (CA) method was adopted to support a transitional zone at the interfaces of piled structures and road embankment. With the CA method a transitional zone was designed at these interfaces to be supported by soil-cement columns of varying lengths to smooth out the settlement profile within these zones. Field monitoring was conducted following completion of remediation. The CA method was also compared with two other Japanese code-designated methods: overlaying a new pavement on the existing pavement at a certain time interval, and constructing a concrete cushion slab under the road pavement. Both practical and economic aspects are examined in the case study presented. This study shows that, when the differential settlement is over 0·3 m, overlay remediation is not economic, and the approach cushion method does not perform well. The CA method not only reduces the differential settlement effectively, but also reduces the total construction cost, although the initial investment is relatively high.

Evaluation of a cushioned method for centrifugation and processing for freezing boar semen

The purpose of this investigation was to evaluate the use of an iodixanol cushion during centrifugation on sperm recovery and yield after centrifugation (sperm recovery, sperm motility, viability, membrane lipid disorder, acrosome reaction and ROS generation); and to investigate how this procedure affects sperm function after freezing–thawing (sperm motility, membrane lipid disorder, acrosomal status and homologous in vitro penetration test). The sperm-rich fractions from fertile boars were centrifuged under two centrifugation régimes: 800 × g for 10 min (standard method) and 1000 × g for 20 min with an iodixanol (60% w/v) cushion at the bottom of the centrifuge tubes (Cushion method). The highest recovery was achieved using the cushion method (sperm loss for cushion method was 0.50% ± 0.18 versus 2.97% ± 0.43 for standard method, P < 0.01) and sperm quality was not significantly affected by the centrifugation régime. The motion parameters (% progressive motility, % motility, VCL, VSL, VAP, ALH, BCF, P < 0.05) of frozen–thawed samples showed higher values using the standard method. However, a higher number of viable spermatozoa with lower lipid disorders were found in spermatozoa processed with the cushion method. The in vitro penetration assay showed that the individual boar influenced the parameters studied but there were no differences between the two centrifugation régimes used. Our results support the hypothesis that the proportion of sperm loss in frozen–thawed semen was significantly influenced by the centrifugation régime. Therefore, the iodixanol cushion method is a suitable tool for cryopreservation of boar semen in order to reduce sperm loss without affecting sperm quality.