Effect Of Loading Method Research Articles

Effect of loading method on catalytic performance of Pt/CeO2 system for CO oxidation

The oxygen vacancies of CeO2 play a pivotal role in effectively dispersing and stabilizing noble metal nanoparticles (NPs). During the NPs loading process, the post-treatment condition, e.g. atmosphere, has a certain influence on the oxygen vacancy concentration of CeO2, highlighting the importance of suitable choice of loading technique. Herein, A-Pt/HCeO2 and I-Pt/HCeO2 catalysts are prepared by loading Pt NPs on HCeO2 with abundant oxygen vacancies (obtained from the calcination of a Ce(OH)CO3 precursor under H2) using ALD deposition and impregnation methods, respectively. Through detailed characterization and in situ DRIFTS analysis, it was noted that compared to the I-Pt/HCeO2 catalyst, the A-Pt/HCeO2 catalyst processes a uniform distribution of Pt NPs, more Pt0 active sites and oxygen vacancies, thus exhibiting an outstanding catalytic performance for CO oxidation. The ALD deposition technique mitigates the effects of high-temperature sintering and atmospheric exposure during the loading process of noble metal NPs, offering a more accurate assessment of the catalytic performance of catalysts.

Mycophenolic Acid-loaded Naïve Macrophage-derived Extracellular Vesicles Rescue Cardiac Myoblast after Inflammatory Injury.

Exosomes are natural endogenous extracellular vesicles with phospholipid-based bilayer membrane structures. Due to their unique protein-decorated membrane properties, exosomes have been regarded as promising drug carriers to deliver small molecules and genes. A number of approaches have been developed for exosome-based drug loading. However, the drug loading capability of exosomes is inconsistent, and the effects of loading methods on the therapeutic efficacy have not been investigated in detail. Herein, we developed anti-inflammatory drug-loaded exosomes as an immunomodulatory nanoplatform. Naïve macrophage-derived exosomes (Mϕ-EVs) were loaded with the anti-inflammatory drug mycophenolic acid (MPA) by three major loading methods. Loading into exosomes significantly enhanced anti-inflammatory and antioxidation effects of MPA in vitro compared to free drugs. These findings provide a scientific basis for developing naïve macrophage-secreted exosomes as drug carriers for immunotherapy.

Effect of Loading Method, Temperature, and Twin Defects on the Mechanical Behavior of Nanocrystalline Ni with Gradient Spacing Twin Structure

Effect of Loading Method, Temperature, and Twin Defects on the Mechanical Behavior of Nanocrystalline Ni with Gradient Spacing Twin Structure

Study on the Effect of Loading Method on Mechanical Behavior of Rockbolt Based on DEM Modeling

Fully grouted rockbolt is a form of reinforcement commonly used in underground projects. Its mechanical behavior is of vital importance to enhancing the stability of surrounding rock masses. To investigate the effect of different loading methods on the mechanical behaviors of rockbolt, the distinct element code PFC2D was adopted to simulate the pullout test on rockbolt and a compression test on the bolted rock mass, with Hongtoushan Copper Mine as the engineering background. The stress distribution along rockbolt and the maximum pullout capacity were analyzed. The results indicated that the loading method has significant effects on the mechanical behaviors of rockbolt. In the pullout test, the peak stress in the rockbolt always occurs near the free face. As the rock mass is a passive load-bearing component, the cracks and weak intercalations in the rock mass have little effect on the mechanical behaviors of the rockbolt. Meanwhile, as the external load acts directly on the outer end of rockbolt, the effect of the bearing plate cannot be reflected. However, in the compression test on the bolted rock mass, the peak stress in the rockbolt gradually transfers to greater depth. The existence of cracks and weak intercalations have an impact on the mechanical behaviors of the rockbolt. In addition, with increasing size of the bearing plate, the maximum pullout capacity of the rockbolt gradually increases. Comparison of the simulation results showed that the maximum pullout capacity obtained by the pullout test on a rockbolt is higher than that obtained by the compression test on a bolted rock mass. Therefore, appropriate reduction of the maximum pullout capacity obtained by the pullout test is suggested for rockbolt design, and the reduction factor should be in the range of 0.7–0.8.

The effect of loading methods on the microstructural evolution and degree of strain localization in Cu50Zr50 metallic glass composite nanowires: A molecular dynamics simulation study

In this work, the Cu50Zr50 metallic glass composite nanowire (MGCNW) is subjected to uniaxial tensile, bending, and cyclic deformation. The effect of loading methods on the microstructural evolution and degree of strain localization is investigated. The simulations are performed using molecular dynamics (MD) code. The embedded atom method (EAM) is used to model the interactions between Cu–Zr atoms. The model for the study is created by embedding spherical copper nanocrystallites (diameter = 50 Å) in the Cu50Zr50 metallic glass matrix. Uniaxial tensile simulations have been carried out at strain rates in the range of 106 s−1 to 109 s−1. Three-point bend tests are carried out at different loading rates (1 m/s to 10 m/s). Finally, a strain-controlled cyclic deformation test is carried out at a strain amplitude of 0.02. All the tests are carried out at a temperature of 300 K. Atomic clusters of high shear strain are observed at the yield that later develops into bands with increasing strain. The degree of strain localization is observed to be higher in the bend tests as compared to the tensile and cyclic deformations. Also, it increases with decreasing strain rate. Voronoi polyhedral analysis reveals the breakdown of (0, 0, 12, 0) icosahedral clusters during plastic deformation, which is prominent during tensile deformation.

Effect of loading methods on progressive collapse behavior of RC beam-slab substructures under corner column removal scenario

In this paper, high-fidelity finite element (FE) models were developed to investigate the behavior of reinforced concrete (RC) beam-slab substructures to resist progressive collapse under a corner column removal scenario. The numerical models were validated by test results. Then, the validated FE models were employed to investigate the structural behavior under different loading methods, including concentrated loading (CL) and uniformly distributed loading (UDL) methods. Moreover, multi-story frames were built to capture the load redistribution behavior of substructures at different floors under different loading methods. The results indicated that the loading methods affect overall structural responses, load transfer mechanisms, and failure modes. It was demonstrated that the Vierendeel action could not be ignored for multi-story frames to resist progressive collapse caused by the loss of a corner column scenario. More significant Vierendeel action was developed in the structure subjected to CL method than that subjected to UDL method. It was also found that the load transfer mechanisms developed in the top story and bottom story for a multi-story frame are pretty different from those in the middle stories. The bottom story has the most remarkable load resisting capacity.

Effect of loading methods on the performance of hierarchical porous carbon/sulfur composites in lithium sulfur batteries

Lithium-sulfur batteries have shown increasing promise for high energy densities and reduced costs. Facile sulfur loading techniques demonstrate a critical way to achieving high dispersions of sulfur in the host's matrix, improving conductivity and simultaneously decreasing the active mass loss from the cathode. Here we investigate the effect of sulfur loading methods on the electrochemical performance of porous carbon/sulfur composites containing approximately 70 wt% sulfur. Three different loading techniques are tested, including one-step molten sulfur impregnation (155°C), two-step molten sulfur impregnation (155°C + 300°C) and a sulfur organic solution impregnation, in which the entire microporous volume of carbon is filled by sulfur. It is found that the simple sulfur organic solution impregnation method is the most effective in enhancing the electrochemical performance of the hierarchical porous carbon/sulfur composite cathode in the lithium-sulfur battery system, due to the weaker interaction occurring between the sulfur and microporous carbon. Our work demonstrates the impact of sulfur loading method on the electrochemical performance of lithium-sulfur batteries, which offers new insights into the preparation technology of electrodes.

Effects of loading methods and oxidation degree of support on the tar reforming activity of char-supported Ni catalyst using toluene as a model compound

It is necessary to remove the tars present in gasification systems of biomass or low-rank coal to prevent the blockage and corrosion of downstream equipment. In this study, catalysts were prepared using different Ni loading methods: impregnation, pressure impregnation, and ion exchange methods using coal char as a catalyst support for tar removal. The catalyst prepared by ion exchange method showed considerably better performance for the steam reforming of toluene (model tar) compared with the other two catalysts. The oxygen-containing groups of low-rank coal acted as cation-exchange sites, and the oxidation significantly increased the number of oxygen-containing groups. Therefore, the intrinsic correlation between oxidation degree of support and catalytic property was further explored. ICP analysis, XRD spectroscopy, and TEM images confirmed that Ni loading and Ni crystallite size (NCS) significantly depended on the oxidation degree of support. When coal was oxidized with 30% H2O2 and 30% HNO3, the Ni loadings of catalysts were 9.9 wt% and 12.1 wt%, and the NCS were 3.5 nm and 4.5 nm, respectively. Compared to HNO3, the catalyst prepared using H2O2 pretreatment exhibited a higher toluene removal efficiency.

Pt/SAPO-11 Catalysts: Effect of Platinum Loading Method on the Hydroisomerization of n-Hexadecane

A series of platinum were supported on a crystalline pure SAPO-11 by different loading methods; ethylene glycol reduction (EG) method and conventional incipient wetness impregnation (IM) technique. Effects of loading method and amount of platinum on the hydroisomerization of n-hexadecane in fixed bed-reactor were investigated. N2 ad/desorption, XRD, NH3-TPD, H2-chemisorption and FE-SEM techniques were employed to study the effects of different preparation methods on the physicochemical and morphological characterization of the prepared samples. The results suggest that the Pt metal particles on the catalyst prepared by (IM) method can be located near the micropore mouth of SAPO-11 support, while the Pt sites on the catalyst prepared by EG method mainly located on the external surface. The 5 wt% Pt (EG)/SAPO-11 catalyst exhibited the best isomerization activity and yield at smaller reaction temperature (300 °C) in the hydroisomerization of n-hexadecane, which is attributed to preferential location of Pt metal particles as it was assessed that the (de)hydrogenation activity function operated by Pt metal particles is a limiting step in the catalytic performance towards improving the isomerization activity of Pt/SAPO-11 catalysts prepared by different methods.

Effect Of Loading Method On Metabolism Of Foreign Molecules In Intact Cells Of Dictyostelium Discoideum

Loading foreign molecules inside living cells allows one to monitor cellular metabolism, track various metabolic pathways and alter activities of the cell. However, the effects of loading methods on the fate of these foreign molecules are poorly understood. In this experiment, we examined three promising loading methods including pinocytosis, electroporation and myristoylation to insert a peptide substrate reporter in cells of Dictyostelium discoideum. These methods were optimized to maximize cell viability, and factors such as loading efficiency, loading duration, localization and uniformity were characterized. Capillary electrophoresis was used to determine how each loading method affected the enzyme activity on the peptide substrate reporter. It was observed that these loading methods had strong effects on the stability and degradation of the peptide. Myristoylation was found to be the most effective method at transporting the peptide into cells while electroporation produced the most uniform loading within cells suggesting cytoplasmic loading. The peptide was degraded most rapidly after loading by myristoylation (half‐life = 12 ± 1 min), while pinocytic loading produced slightly slower degradation (half‐life = 19 ± 2 min). Phosphorylation of the peptide was only observed in cells loaded with electroporation. This experiment suggests that the choice of loading method influences the stability and metabolism of foreign molecules in cells. Our future work includes investigating the specificity of different peptide substrate reporters in Dictyostelium lysates.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Experimental investigation of CFS steel sheathed shear walls with openings using self-piercing rivets

This paper presents an experimental investigation of self-piercing riveted cold-formed steel (SPRCFS) shear walls with openings under monotonic and reversed cyclic loading. The effects of loading method and wall's openings ratio on the behavior and failure modes of SPRCFS shear walls were studied. Based on the test results researched, the damage levels of intact, slight, moderate, and severe were defined. The story drift angles under different damage levels were also determined. The existing shear wall design methods were analyzed for their feasibility on the shear strength of SPRCFS shear walls with openings and a new design method for SPRCFS shear walls with openings was proposed. The research indicated that the major failure modes of SPRCFS shear walls with openings were in the sheet buckling and SPR connections failure at the edge of openings. The shear strength and stiffness decreased with the increase of opening's ratio, and the strength reduction can be neglected by reinforcing construction measures when the openings ratio is less than 5.6%. Wall openings can effectively improve ductility of walls, but it also can cause the decrease of ductility when openings ratio is over 38.9%. 1/300 rad was suggested as the elastic story drift angle for wind loads and 1/100 rad was recommended to be the elastic-plastic story drift angle for seismic loads.

Repair of Fire-Damaged Reinforced Concrete Members with Axial Load: A Review

It is common knowledge that structural fires have led to a great loss of buildings and damage to property in the past two decades. Therefore, there is a growing need to provide approaches for post-fire repair of structural members to enhance their structural safety. This paper presents a state-of-the-art review on the repair of fire-damaged reinforced concrete (RC) members with axial load. The investigations into the effects of loading method, physical dimension and bonding behavior on the residual strength of members are presented. In the meantime, the available experimental investigations on the performance of fire-damaged RC members with axial load repaired with concrete jacketing, steel jacketing and fiber-reinforced polymer (FRP) jacketing are summarized. Moreover, models for predicting the residual strength of fire- damaged columns are reviewed.

The Construction of Sustained-Release Systems of Tanshinone IIA and Sodium Tanshinone IIA Sulfonate by SBA-15 Mesoporous Material.

The basic problems of the low dissolution rate of Tanshinone IIA (TSN) and the instability and precipitation of sodium tanshinone IIA sulfonate (STS) injection limit their usage in clinical. For these facts, the study aims to improve the dissolution rate of TSN and to enhance the sustained release effects of TSN and STS by using SBA-15 mesoporous molecular sieve as a drug carrier. Furthermore, controlling the pore size of SBA-15 and using different loaded methods to achieve expectations and provide a novel scheme for existing Danshen formulations. The effect of loading methods on drug loading efficiency (DL%), as well as the influence of the pore size of SBA-15s, the drug polarities and release mediums on drug loading and release behaviors were analyzed. It was found that the DL% was enhanced with the enlargement of the pore size, and was higher of TSN than STS. The in vitro tests of drug-loaded SBA-15s confirmed that the dissolution rate of TSN was improved obviously as compared with pure TSN. Moreover, SBA-15s prolonged the release times up to 12 h of TSN and 60 h of STS and promoted the sustained-release behaviors by decreasing the pore size. To ascertain the kinetic mechanisms of these samples, the Korsmeyer-Peppas release model was employed and the fitted results indicated that TSN/SBA-15s followed Fickian diffusion and non-Fickian transport was the predominant kinetic release mechanisms for STS/SBA-15s.

Effect of Loading Method on a Peptide Substrate Reporter in Intact Cells.

Studies of live cells often require loading of exogenous molecules through the cell membrane; however, effects of loading method on experimental results are poorly understood. Therefore, in this work, we compared three methods for loading a fluorescently labeled peptide into cells of the model organism Dictyostelium discoideum. We optimized loading by pinocytosis, electroporation, and myristoylation to maximize cell viability and characterized loading efficiency, localization, and uniformity. We also determined how the loading method affected measurements of enzyme activity on the peptide substrate reporter using capillary electrophoresis. Loading method had a strong effect on the stability and phosphorylation of the peptide. The half-life of the intact peptide in cells was 19 ± 2, 53 ± 15, and 12 ± 1 min, for pinocytosis, electroporation, and myristoylation, respectively. The peptide was phosphorylated only in cells loaded by electroporation. Fluorescence microscopy suggested that the differences between methods were likely due to differences in peptide localization.

Kaempferol-immobilized titanium dioxide promotes formation of new bone: effects of loading methods on bone marrow stromal cell differentiation in vivo and in vitro.

BackgroundSurface modification of titanium dioxide (TiO2) implants promotes bone formation and shortens the osseointegration period. Kaempferol is a flavonoid that has the capacity to promote osteogenic differentiation in bone marrow stromal cells. The aim of this study was to promote bone formation around kaempferol immobilized on TiO2 implants.MethodsThere were four experimental groups. Alkali-treated TiO2 samples (implants and discs) were used as a control and immersed in Dulbecco’s phosphate-buffered saline (DPBS) (Al-Ti). For the coprecipitation sample (Al-cK), the control samples were immersed in DPBS containing 50 µg kaempferol/100% ethanol. For the adsorption sample (Al-aK), 50 µg kaempferol/100% ethanol was dropped onto control samples. The surface topography of the TiO2 implants was observed by scanning electron microscopy with energy-dispersive X-ray spectroscopy, and a release assay was performed. For in vitro experiments, rat bone marrow stromal cells (rBMSCs) were cultured on each of the TiO2 samples to analyze cell proliferation, alkaline phosphatase activity, calcium deposition, and osteogenic differentiation. For in vivo experiments, TiO2 implants placed on rat femur bones were analyzed for bone–implant contact by histological methods.ResultsKaempferol was detected on the surface of Al-cK and Al-aK. The results of the in vitro study showed that rBMSCs cultured on Al-cK and Al-aK promoted alkaline phosphatase activity, calcium deposition, and osteogenic differentiation. The in vivo histological analysis revealed that Al-cK and Al-aK stimulated new bone formation around implants.ConclusionTiO2 implant-immobilized kaempferol may be an effective tool for bone regeneration around dental implants.

Insight into natural biopolymer-emulsified solid lipid nanoparticles for encapsulation of curcumin: Effect of loading methods

Encapsulation of lipophilic bioactives into solid lipid nanoparticles (SLNs) has been a promising approach to incorporate them into functional foods with attempt to improve bioavailability. Nevertheless, how these bioactives should be loaded into the lipid core have never been systematically studied before. Thus, in the present study, biopolymer-emulsified SLNs were prepared using a recently developed synthetic surfactant-free technique, and four different loading methods were tested for their efficacy to encapsulate curcumin into SLNs. Sodium caseinate (NaCas) and pectin were used as natural emulsifier and stabilizer, respectively, to prepare food-grade SLNs using stearic acid. Four loading methods varied in the use of organic solvent, and the order of critical steps including addition of curcumin and solid lipids, deprotonation of NaCas at pH 12, as well as pectin adsorption at pH 4. The resulting four types of curcumin-loaded SLNs were subject to comprehensive characterization, such as measurement of particle size, polydispersibility, zeta potential, stability test in simulated gastrointestinal (GI) fluids, antioxidant activities of encapsulated curcumin, as well as morphological observation under transmission electron microscopy. Nano spray drying technology was then exploited to obtain ultrafine powders from colloidal SLNs and their redispersibility in water was also evaluated. Our results suggested that solubilization of curcumin in deprotonated NaCas was a better approach than using organic solvent which resulted in large and aggregated SLNs. Furthermore, mixing curcumin with deprotonated NaCas and then adding melted lipid and pectin at pH 12 before emulsification were the two critical steps in fabricating uniform and small SLNs that were GI-stable and re-dispersible in water after spray drying. This study provides insight into the preparation of natural biopolymer-emulsified SLNs as a potential food-grade oral delivery system for lipophilic bioactives.

Effect of Drug Loading Method and Drug Physicochemical Properties on the Material and Drug Release Properties of Poly (Ethylene Oxide) Hydrogels for Transdermal Delivery.

Novel poly (ethylene oxide) (PEO) hydrogel films were synthesized via UV cross-linking with pentaerythritol tetra-acrylate (PETRA) as cross-linking agent. The purpose of this work was to develop a novel hydrogel film suitable for passive transdermal drug delivery via skin application. Hydrogels were loaded with model drugs (lidocaine hydrochloride (LID), diclofenac sodium (DIC) and ibuprofen (IBU)) via post-loading and in situ loading methods. The effect of loading method and drug physicochemical properties on the material and drug release properties of medicated film samples were characterized using scanning electron microscopy (SEM), swelling studies, differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FT-IR), tensile testing, rheometry, and drug release studies. In situ loaded films showed better drug entrapment within the hydrogel network and also better polymer crystallinity. High drug release was observed from all studied formulations. In situ loaded LID had a plasticizing effect on PEO hydrogel, and films showed excellent mechanical properties and prolonged drug release. The drug release mechanism for the majority of medicated PEO hydrogel formulations was determined as both drug diffusion and polymer chain relaxation, which is highly desirable for controlled release formulations.

Effects of loading methods on microstructure of diffusion welded joint of AZ31B/Cu with Ni interlayer

Diffusion brazing was carried out to weld AZ31B magnesium alloy and copper with Ni foil interlayer under different loading methods that are divided into intermittent gradient pressure, gradient pressure and constant pressure. The microstructure and element diffusion of welded joint were analyzed by SEM and EDS. The results show that the AZ31B/Cu can achieve good bonded joint composed of brazing seam zone and magnesium substrate grain boundary penetration zone at 500 °C for 20 min. The loading methods have great influence on the thickness of brazing seam zone, microstructure and α-Mg grain size of the welded joint. At intermittent gradient pressure, the brazing seam zone reaches the biggest width of 0.18 mm, and the microstructure of brazing seam zone is composed of Cu11Mg10Ni9, (α-Mg+Mg2Cu+Mg2Ni)eutectic structure and α-Mg. Under gradient pressure, the width of brazing seam zone reduces, and the microstructure of brazing seam zone is mainly dominated by (α-Mg+Mg2Cu+Mg2Ni)eutectic structure and Cu11Mg10Ni9 compounds closed magnesium matrix. When using constant pressure, the microstructure of joint is similar to that under intermittent gradient pressure, the brazing seam zone reaches the smallest width of 0.11 mm, and the size of α-Mg grains reduces.

The effect of loading methods and parameters on defect detection in digital shearography

Digital Shearography Speckle Pattern Interferometry (DSSPI) is a non-destructive testing technique, which has a wide range of applications in industrial field due to the merits of non-contact, fast response, full-field measurement and high sensitivity. However, in the real application, the loading methods and parameters usually depend on the experience of the operator, which affect the effectiveness and accuracy of the test. Based on this background and the principle of DSSPI, a model using finite element analysis software and Matlab is established to simulate the defects detections of aluminum plate and composite laminates under different loading conditions. The simulation covers loading methods, shearing direction, shearing amount, loading intensity, defect size, defect depth and defect position. In order to quantify the testing effect, a parameter named the deviation D is first defined. And through the parameter D, the simulation system can evaluate the system detection ability. The work in this paper can provide systematic guidance for the choice of loading methods and parameters in the real DSSPI experiment system.

スーパー二相ステンレス鋼の疲労強度に及ぼす荷重様式と平均応力の影響

スーパー二相ステンレス鋼の疲労強度に及ぼす荷重様式と平均応力の影響