Abrasion Model Research Articles

Evaluation of BepanGel Hydrogel Efficacy and Tolerability Using an Abrasive Wound Model in a Within-Person, Single-Center, Randomized, Investigator-Blind Clinical Investigation.

IntroductionOver the last few years, it has been demonstrated that a moist environment enhances the healing process and reduces scar formation of wounds. Such moist conditions can be created and maintained using hydrogels. The aim of this study was to evaluate wound healing, cooling efficacy, local tolerability, and cosmetic appearance of abrasive wounds treated with BepanGel wound care hydrogel.MethodsThis study was designed as a within-person, single-center, randomized, investigator-blind clinical investigation comparing a hydrogel-treated test field with an untreated test field in an abrasive wound model. In 33 subjects, two small superficial wounds were induced on the non-dominant forearms. Wounds were treated with BepanGel and covered with a standard semi-occlusive wound plaster or covered with a plaster alone for 11 consecutive days. Wound healing efficacy, cooling effect, and tolerability of the treatment were assessed over 12 investigational days. During follow-up at day 31, the cosmetic appearance of the wounds was evaluated.ResultsOn day 12, the test field treated with BepanGel was completely healed in nearly all subjects (97.0%) in contrast with the test field treated with a plaster alone (18.2%, AUCdays 2–12 p < 0.0001) as assessed by a blinded investigator. Two-thirds of the unblinded subjects indicated an immediate cooling effect of the hydrogel (p = 0.0555). At the end of the investigation, the cosmetic appearance of the BepanGel-treated test fields scored superior to the fields treated with a plaster alone as evaluated by a blinded investigator (p = 0.0005) and the unblinded subjects (p = 0.0078). The hydrogel was generally well tolerated and no signs of infection or adverse events (AEs) related to the treatment were observed.ConclusionThis evaluation shows that treatment of superficial cutaneous wounds with BepanGel results in improved wound healing as demonstrated by faster wound closure and a considerably better cosmetic appearance, while providing immediate cooling.Trial Registration NumberEUDAMED-No.: CIV-19-09-029744.Electronic supplementary materialThe online version of this article (10.1007/s13555-020-00432-5) contains supplementary material, which is available to authorized users.

Mechanistic force modeling in drilling of SiCp/Al matrix composites considering a comprehensive abrasive particle model

SiCp/Al composite is one of the key light metal matrix composites widely used in aerospace and electronics industries due to its excellent material properties. Understanding the mechanism of abrasive particle action and the cutting force generation is crucial for achieving desired hole quality and machining accuracy. However, there is no research on cutting force modeling in drilling of SiCp/Al composites. This paper proposes an energy-based mechanistic modeling method to predict the cutting force in drilling of SiCp/Al composites for the first time. A new comprehensive abrasive particle model considering different particle action mechanisms, such as cracking, debonding, and squeezing, is presented to depict the energy consumed by abrasive particle action. Experiments with a wide range of particle volume fractions and feed rates, and different particle sizes were carried out to validate the accuracy of the proposed model. Results show that the proposed model can accurately predict the cutting force with an average error of 6.55% in drilling of SiCp/Al composites. Furthermore, the energy consumed on abrasive particle action is estimated to be 8.2–13.6% of total cutting energy. The proposed model on SiCp/Al composites can be extended to other particle reinforced metal matrix composites.

Failure behavior of projectile abrasion during high-speed penetration into concrete

The mass abrasion of projectile is an obvious failure phenomenon because of mass loss and nose blunting during the high-speed projectile deep penetration into concrete target. The thermal melting and cutting by aggregate on projectile outer surface are the main mechanisms of mass abrasion according to the experimental observation. In this paper, a coupled melting-cutting model is constructed to estimate mass abrasion and dynamic behavior of ogive-nose projectile during penetration. In this model, the abrasion volume of melting and cutting are obtained by two-dimensional heat conduction equation and a classic abrasive theory including a parameter that related to aggregate strength, respectively. Furthermore, the two mechanisms of mass abrasion interact with each other and are connected by the Johnson–Cook model. Finally, the penetration performance parameters, i.e., depth of penetration, variation of projectile shape and mass loss rate, can be obtained by the iteration calculation based on coupled abrasion model. The theoretical predictions agree well with the typical experimental data. Besides, the effects of the model parameters on the penetration performance are discussed.

A new abrasive wear model for railway ballast

A new method to model the abrasion of granular particles using the discrete element method is demonstrated in this paper. This new, simple method is based on a classical theory of abrasive wear, relating the volume of solid lost to the frictional work at particle contacts. The modelling technique is demonstrated in simulations of railway ballast using realistically-shaped particles, which are compared to experimental data. The new abrasion model correctly introduces stress-dependent behaviour at small strains into the simulations, which is essential for any realistic discrete element model.

Dual dynamically crosslinked thermosensitive hydrogel with self-fixing as a postoperative anti-adhesion barrier

Tissue adhesion is a severe postoperative complication. Various strategies have been developed to minimize postoperative adhesion, but the clinical efficacy is still far from satisfactory. Herein, we present a dual dynamically crosslinked hydrogel to serve as a physical postoperative anti-adhesion barrier. The hydrogel was generated by dynamic chemical oxime bonding from alkoxyamine-terminated Pluronic F127 (AOP127) and oxidized hyaluronic acid (OHA), as well as hydrophobic association of AOP127. Rheological analysis demonstrated that the hydrogel exhibits temperature sensitivity. At 37 °C, it shows much higher modulus and higher stability than the Pluronic F127 hydrogel. Hemolytic assays suggested that the hydrogel undergoes low hemolysis. In addition, it exhibited anti-adhesion to blood cells in blood cell adhesion tests. It also showed an anti-attachment effect to fibroblasts and biocompatibility in vitro cell studies. Macroscopic evaluation and lap-shear tests revealed that the hydrogel has a moderate adhesive capacity to tissue, which is important for self-fixation. A rat model of sidewall defect-bowel abrasion was established to evaluate the anti-adhesion effect in vivo. The gross observation and pathological analysis revealed a significant reduction in postoperative peritoneal adhesion in the AOP127/OHA hydrogel-treated group than those treated with normal saline or Pluronic F127 hydrogel. Hence, the dual dynamically crosslinked hydrogel with self-fixable capacity may be suitable as a physical barrier for postoperative adhesion prevention. Statement of SignificanceDespite the development of numerous postoperative anti-adhesion barriers, their anti-adhesion efficacy is still limited in clinical trials due to poor tissue adhesion and rapid clearance from injured areas. Herein, we have developed a dual dynamic crosslinked hydrogel, generated by dynamic oxime bonds and hydrophobic interactions. The hydrogel is temperature-sensitive and demonstrates moderate tissue adhesion capacity, which allows for self-fixation when applied to defects. The introduction of dynamic covalent bonds improves the stability of the hydrogel. Moreover, the hydrogel not only displays appropriate hemocompatibility, cytocompatibility and anti-adhesion of blood cells and fibroblasts, but it also effectively contributes to preventing postoperative peritoneal adhesions in vivo. Hence, this dual dynamic crosslinked hydrogel may have potential applications as a physical barrier in clinical practice.

The neuroregenerative effects of topical decorin on the injured mouse cornea

BackgroundThe cornea is innervated with a rich supply of sensory nerves that play important roles in ocular surface health. Any injury or pathology of the corneal nerves increases the risk of dry eye disease and infection. This study aims to evaluate the therapeutic potential of topical decorin to improve corneal nerve regeneration in a mouse model of sterile epithelial abrasion injury.MethodsBilateral central corneal epithelial abrasions (2-mm, Alger Brush) were performed on young C57BL/6 J mice to remove the corneal sensory nerves. Decorin, or vehicle, was applied topically, three times per day for 1 week or every 2 h for 6 h. Spectral-domain optical coherence tomography was performed to measure the abrasion area and corneal thickness. Wholemount immunofluorescence staining was used to assess sensory nerve regeneration (β-tubulin III) and immune cell density (CD45, Iba1, CD11c). To investigate the specific role of dendritic cells (DCs), Cx3cr1gfp/gfp mice, which spontaneously lack resident corneal epithelial DCs, were also investigated. The effect of prophylactic topical administration of recombinant human decorin (applied prior to the abrasion) was also investigated. Nerve tracing (NeuronJ software) was performed to compare recovery of basal nerve axons and superficial nerve terminals in the central and peripheral cornea.ResultsAt 6 h after injury, topical decorin application was associated with greater intraepithelial DC recruitment but no change in re-epithelialisation or corneal thickness, compared to the vehicle control. One week after injury, sub-basal nerve plexus and superficial nerve terminal density were significantly higher in the central cornea in the decorin-treated eyes. The density of corneal stromal macrophages in the decorin-treated eyes and their contralateral eyes was significantly lower compared to saline-treated corneas. No significant improvement in corneal nerve regeneration was observed in Cx3cr1gfp/gfp mice treated with decorin.ConclusionsDecorin promotes corneal epithelial nerve regeneration after injury. The neuroregenerative effect of topical decorin was associated with a higher corneal DC density during the acute phase, and fewer macrophages at the study endpoint. The corneal neuroregenerative effects of decorin were absent in mice lacking intraepithelial DCs. Together, these findings support a role for decorin in DC-mediated neuroregeneration following corneal abrasion injury.

Polysaccharide-based films for the prevention of unwanted postoperative adhesions at biological interfaces

Postoperative adhesions protect, repair, and supply nutrients to injured tissues; however, such adhesions often remain permanent and complicate otherwise successful surgeries by tethering tissues together that are normally separated. An ideal adhesion barrier should not only effectively prevent unwanted adhesions but should be easy to use, however, those that are currently available have inconsistent efficacy and are difficult to handle or to apply. A robust hydrogel film composed of alginate and a photo-crosslinkable hyaluronic acid (HA) derivative (glycidyl methacrylate functionalized hyaluronic acid (GMHA)) represents a solution to this problem. A sacrificial porogen (urea) was used in the film manufacture process to impart macropores that yield films that are more malleable and tougher than equivalent films produced without the sacrificial porogen. The robust mechanical behavior of these templated alginate/GMHA films directly facilitated handling characteristics of the barrier film. In a rat peritoneal abrasion model for adhesion formation, the polysaccharide films successfully prevented adhesions with statistical equivalence to the leading anti-adhesion technology on the market, Seprafilm®. Statement of SignificancePostoperative adhesions often remain permanent and complicate otherwise successful surgeries by tethering tissues together that are normally separated and pose potentially significant challenges to patients. Therefore, the generation of adhesion barriers that are easy to deploy during surgery and effectively prevent unwanted adhesions is a big challenge. In this study robust hydrogel films composed of alginate and a photo-crosslinkable hyaluronic acid (HA) derivative (glycidyl methacrylate functionalized HA, GMHA) were fabricated and investigated for their potential to act as a solution to this problem using a rat peritoneal abrasion model for adhesion formation. We observed the polysaccharide films successfully prevented adhesions with statistical equivalence to the leading anti-adhesion technology on the market, Seprafilm®, suggesting that such films represent a promising strategy for the prevention of postoperative adhesions.

Field Investigation on Hydroabrasion in High-Speed Sediment-Laden Flows at Sediment Bypass Tunnels

Wear due to sediment particles in fluid flows, also termed ‘hydroabrasion’ or simply ‘abrasion’, is an omnipresent issue at hydraulic structures as well as in bedrock rivers. However, interactions between flow field, particle motion, channel topography, material properties and abrasion have rarely been investigated on a prototype scale, leaving many open questions as to their quantitative interrelations. Therefore, we investigated hydroabrasion in a multi-year field study at two Swiss Sediment Bypass Tunnels (SBTs). Abrasion depths of various invert materials, hydraulics and sediment transport conditions were determined and used to compute the abrasion coefficients kv of different abrasion models for high-strength concrete and granite. The results reveal that these models are useful to estimate spatially averaged abrasion rates. The kv‑value is about one order of magnitude higher for granite than for high-strength concrete, hence, using material-specific abrasion coefficients enhances the prediction accuracy. Three-dimensional flow structures, i.e., secondary currents occurring both, in the straight and curved sections of the tunnels cause incision channels, while also longitudinally undulating abrasion patterns were observed. Furthermore, hydroabrasion concentrated along joints and protruding edges. The maximum abrasion depths were roughly twice the mean abrasion depths, irrespective of hydraulics, sediment transport conditions and invert material.

Experimental Investigation and Simulation of Aircraft Tire Wear

ABSTRACT Not only in the automotive sector, but also in the field of aircraft tires, the topic of abrasion is of great importance. The aircraft tire manufacturers provide criteria for the permissible degree of wear. If these limits are exceeded, the tire must be replaced or retreaded. By this time, the tire should withstand as many takeoff and landing cycles as possible. Abrasion models should help to predict the wear behavior in preflight modeling. At the Institute of Dynamics and Vibration Research, quasi-steady abrasion tests are performed using tread block samples from an aircraft tire. For various pressures and sliding speeds, the abrasion is determined by recording the mass loss of the rubber sample. Based on these measurement data, a wear model is derived as a function of coefficient of friction, contact pressure, and sliding speed for different ambient temperatures. The well-known brush model forms the basis for the wear simulations. With parameters validated on the aircraft tire, such as contact length, stiffness, and friction coefficient, the resulting mechanical forces within the contact area are calculated. Finally, the classic brush model is extended by the abrasion calculation. The tire wear is determined during unsteady load and slip conditions by use of the quasi-steady wear maps derived from our experiments. Within a measurement campaign on the complete tire, the tread depth is measured after various driving maneuvers and is in good agreement with the simulation results.

A Comparative Efficacy Evaluation of Recombinant Topical Thrombin (RECOTHROM®) With A Gelatin Sponge Carrier Versus Topical Oxidized Regenerated Cellulose (TABOTAMP®/SURGICEL®) In A Porcine Liver Bleeding Model

Purpose Topical hemostatic agents can be classified as active or passive. This study compared the hemostatic efficacy of an active agent, recombinant thrombin (RECOTHROM® [rT]) plus gelatin sponge carrier versus a passive agent, oxidized regenerated cellulose (TABOTAMP®/SURGICEL® [ORC]), in a porcine liver abrasion model. Materials and Methods Eight pigs were used, four of them were heparinized. A total of 80 liver lesions were created, 40 of them in heparinized pigs. Lesions were treated with rT plus gelatin sponge or ORC. Bleeding rate was quantified before treatment by applying pre-weighed gauze. Time to hemostasis was assessed visually for 10 minutes. Results Seven of the 80 lesions were excluded for having initial bleeding rates exceeding the target of 10 g/min. Sixteen and 20 lesions were treated with rT plus gelatin sponge and 19 and 18 lesions were treated with ORC, in non-heparinized and heparinized animals, respectively. Time to hemostasis (median [IQR]) was significantly shorter with rT plus gelatin sponge (30 [30,30] seconds) in heparinized and non-heparinized animals versus ORC in non-heparinized (180 [120,210] seconds) and heparinized animals (215 [135,345] seconds); P < 0.0001 for both comparisons. In heparinized animals, ORC took longer to achieve hemostasis, with treatment failure in 2/18 lesions. Time to hemostasis with ORC was longer for lesions in heparinized animals with initial bleeding rates of >5–10 g/min (285 [225,394] seconds) versus ≤5 g/min (175 [108,290] seconds). Conclusions In this model, rT plus gelatin sponge carrier (active) was a more effective hemostat than ORC (passive) in both heparinized and non-heparinized animals.

Thermal stimuli-responsive hyaluronic acid loaded cellulose based physical hydrogel for post-surgical de novo peritoneal adhesion prevention.

Effective strategies for post-surgical adhesion prevention have increasingly focused on injectable adhesion barriers due to their minimal invasiveness and wider applicability. In this study, a thermo-reversible hydrogel was developed by combining high molecular weight hyaluronic acid (HA) at various concentrations (0.05, 0.25, and 0.45% w/v) with tempo-oxidized nanocellulose (TOCN), methyl cellulose (MC) and polyethylene glycol (PEG) for anti-adhesion application. The hydrogel preparation time was short and did not require any chemical modification. TOCN ensured the mechanical stability of the hydrogel. MC confirmed thermo-sensitive feature. Higher amounts of HA increased the rate of hydrogel degradation. The HA 0.25 hydrogel was free-flowing, injectable at ambient temperature, capable of faster (40±2s), and reversible sol-gel (4°C-37°C) transition. A rat side-wall cecum abrasion model was used to confirm the complete de novo adhesion prevention efficacy of optimized HA 0.25 hydrogel, where the scratched abdominal wall of animals treated with HA 0.25 hydrogel healed after 14days. During in vivo experiment, PEG in the hydrogel played a crucial role in adhesion prevention by minimizing friction between the surgical site and nearby organs. In a nutshell, HA 0.25 hydrogel, fabricated without crosslinking agent, is a potential candidate for tissue adhesion prevention strategies.

A numerical approach for predicting the remaining useful life of an aviation hydraulic pump based on monitoring abrasive debris generation

Abstract The effective operation of aviation hydraulic pumps is directly related to the safety of passengers. Accurate remaining useful life (RUL) prediction will help establish maintenance strategy, which will reduce the risks of passengers. Currently, the degradation processes developing in the aviation hydraulic pump cannot be accurately modeled, because of the complexity of the experiment and lack of data. To address the problem, we resort to a numerical approach in this paper, taking uncertainty into consideration. Wear debris features are simulated by Monte Carlo sampling from an abrasive debris generation model. The model describes the relationship between rough surfaces and abrasive debris at the microscale level. A partition-integration RUL prediction framework is proposed to apply the microscale model to the macroscale process of pump degradation. The proposed method is validated by experimental data. The results show that the model is able to cover extreme dry contact conditions and gives good results with small amounts of data.

Controlled release of Mitomycin C from modified cellulose based thermo-gel prevents post-operative de novo peritoneal adhesion

The complications from surgery associated peritoneal adhesion can be alleviated by combination of physical isolation and pharmaceutical treatment. This work aims to develop thermo-sensitive hydrogel barrier by combining mitomycin C (MMC) with modified tempo oxidized nanocellulose (cTOCN) through EDC/NHS-chemical conjugation followed by integration with methyl cellulose (MC). The MMC was successfully combined with cTOCN and ensured controlled release of MMC from hydrogel throughout 14 days. Amount of MC (1.5, 2.5, 3.5% w/v) was proportional to gelation time and inversely proportional to degradation of hydrogel. The optimized hydrogel (C2.5T1M0.2) needed only 30 s for thermoreversible sol-gel (4℃-37℃) phenomenon and did not show in vitro fibroblast cells toxicity as well as ensured complete adhesion prevention efficacy, reperitonealization in rat side wall-cecal abrasion model. Overall, the developed C2.5T1M0.2 thermo-gel advances state-of-the-art in view of cytocompatibility, mechanical stability, optimum degradation, good injectability, sustain drug release from surgical sites, and satisfactory de novo anti-adhesion capacity.

Prevention of postoperative peritoneal adhesions in rats with sidewall defect-bowel abrasions using metal ion-crosslinked N-succinyl chitosan hydrogels

In situ injectable hydrogels have attracted much attention as adhesion barriers. In this study, N-succinyl chitosan (CH-Su) hydrogels were crosslinked with various polyvalent metal ions (Fe3+, Al3+, and Ca2+) and were developed for the prevention of peritoneal adhesions. CH-Su hydrogels crosslinked with Fe3+ (CH-Su/Fe3+) or Al3+ (CH-Su/Al3+) indicated higher Young's modulus, longer degradation times, and shorter gelation times compared with those crosslinked with Ca2+ (CH-Su/Ca2+). In addition, CH-Su/Fe3+ hydrogels had higher Young's modulus than CH-Su/Al3+ hydrogels, likely reflecting differences in stability constants between CH-Su and each ion. Although while CH-Su/Al3+ and CH-Su/Ca2+ hydrogels were not significantly cytotoxic in cell viability assays, CH-Su/Fe3+ hydrogels showed significantly higher cytotoxicity than controls, presumably due to the release of Fe3+ and decreases in pH. Consistent with the ion-dependent hydrogel properties above, CH-Su/Al3+ hydrogels showed the highest anti-adhesive effects, and significantly decreased adhesion scores in a rat model of sidewall defect-bowel abrasion.

Waterjet Erosion Model for Rock-Like Material Considering Properties of Abrasive and Target Materials

In this study, we investigated the characteristics of abrasive erosion considering the material properties of abrasives and targets. An abrasive particle erosion model considering energy transfer due to hardness differences was developed based on energy conservation using the correlation between volume removal and effective kinetic energy. To obtain the effective erosion kinetic energy of an abrasive, an acceleration model was derived for the abrasive particles, including terms describing the properties of the abrasive and fluid. The applicability of the suggested model was verified by comparing the brittle erosion results obtained using a previous theoretical approach to those of the present numerical analysis. The results obtained using the developed model exhibited good qualitative agreement with the brittle material erosion results. By evaluating acceleration and the erosion characteristics of an abrasive, the erosion performance could be predicted and optimized.

Honed surface multi-scale Prediction based on multi-stage honing process of engine cylinder bore

Abstract Sequential honing process is usually implemented in engine cylinder bore processing to obtain the cross-hatched surface texture with excellent function to balance lubricant storage capacities and supporting performance. Many researches have devoted to correlating honed surface quality of cylinder bore with honing process parameters by means of experiments or simulations. Quite a few efforts have addressed the effect of sequential multiple steps on the surface texture in the honing of engine cylinder bore. However, these researches cannot provide an explicit and analytical methodology to predict honed surface texture efficiently and accurately. This paper presents an analytical and explicit methodology to incorporate a proposed microscale abrasive model into the analytical simulation process of sequential honing. The proposed abrasive model synthetically considers the shape, size, posture, and position of abrasives randomly distributed in honing stone, which is incorporated into honing head motions in terms of rotation, oscillation and feeding. The kinematics of honing head is calculated by space-time discretization to capture the interaction between honing stones and cylinder bore surface. The above procedure acts as each single step for the sequential honing processes. This study investigates the sequential honing of two stages including semi-finish honing and plateau honing at different feeding speeds by applying the abrasive model with different abrasive sizes. The formation of cross-hatched surface texture was successfully achieved sequentially by semi-finish honing and plateaus honing. Then the Abbott-Firestone Curve of the honed surface can be obtained to analyze the influences of abrasive size and honing time of two stages on the surface roughness. Correctness of surface roughness predicted by the model is verified by comparing with a group of experiment measurements in terms of Abbott-Firestone Curve. Most errors of all the predicted Rk roughness family roughness parameters in the two honing stages are less than 15%. Based on the model, simulations are done to analyze the influences of abrasive size and honing duration time of two stages on the surface roughness. The result shows that the larger abrasive used in finish honing leads to the decrease of the material portions Mr1, Mr2 and the increase of the reduced valley depth Rvk. The longer plateau honing duration time is preferred to produce the larger Mr1, Mr2 and the smaller Rvk.

Fatigue life prediction of clutch sleeve based on abrasion mathematical model in service period

AbstractTo predict the service life of clutch sleeve, major reasons for the change of clearance between the clutch sleeve and shell in service period are analysed. A mathematical model of the clearance is established considering abrasion of the step outside sleeve caused by friction. To determine the size of abrasion, a micro‐convex body model for the friction surface is built. Based on surface fatigue abrasion theory, an abrasion model is established. A life model is established based on the entire abrasion of the sleeve. Fatigue life of sleeve is predicted using the model based on actual surface morphology parameters of the enterprise products. Major factors affecting the abrasion speed are discussed and determined after the prediction result is analysed.

On energetic evaluation of robotic belt grinding mechanisms based on single spherical abrasive grain model

A tentative study from the perspective of abrasive grain geometry in this paper is conducted to investigate the specific energy and energy efficiency for clarifying the robotic belt grinding mechanisms. The energy efficiency model is established based on the friction coefficient model of the single spherical grain, then the experiments and simulation are implemented to energetically evaluate the microscale material removal mechanisms from the specific energy contributions. It has been demonstrated that the specific plowing energy is more predominant than both the specific cutting and sliding energy in robotic belt grinding, resulting in the energy efficiency ranges between 17 and 41 %. Both the large grain size and normal contact force can be taken as optimization strategies to maximize the energy efficiency for material removal.

Engineering antimicrobial and biocompatible electrospun PLGA fibrous membranes by irradiation grafting polyvinylpyrrolidone and periodate

Postoperative adhesion may form as the result of a complicated fibrosis and inflammatory response, thus leads to a series of complications or increases the risk of surgery failure. Herein, we prepared poly (lactic-co-glycolic acid)-graft-polyvinylpyrrolidone/polyiodide (PLGA-g-PVP/I) electrospun fibrous membranes to prevent postoperative adhesion and infection formation. Firstly, hydrophilic PVP molecules were grafted on the surface of PLGA powders by gamma ray, and then iodine ions were coordinated with the grafted PVP. Subsequently, PLGA-g-PVP/I fibrous membranes were prepared by electrospinning. The PLGA-g-PVP/I membranes were analyzed via UV–vis, FTIR, Raman, and XPS. The formed polyiodide endowed the membranes with sustained antibacterial activity. The antimicrobial property of PLGA-g-PVP/I membranes was ascribed to the synergistic effect of intracellular ROS production and glutathione oxidation. Furthermore, the prevention efficacy of postoperative abdominal adhesion from the PLGA-g-PVP/I composite membranes was characterized in a rat model of sidewall defect-cecum abrasion. The results demonstrated that the PLGA-g-PVP/I fibrous membranes could prevent the postoperative abdominal adhesion effectively. Therefore, to endow the PLGA-g-PVP/I electrospun fibrous membranes with durable antibacterial property may be a promising strategy towards an anti-bacterial and anti-adhesion system for commercial and clinical uses.

Calibration of the Swedish studded tyre abrasion wear prediction model with implication for the NORTRIP road dust emission model

ABSTRACT An experimentally based prediction model of road abrasion wear due to studded tyres is available in Sweden and has been found to work well. However, it has not been validated since 2007, and since then road surfaces and tyre design have developed, and the question has arisen regarding the model’s current validity. The abrasion wear model is used in the NORTRIP emission model (NOn-exhaust Road Traffic Induced Particle emission modelling), and the effect of a recalibrated abrasion wear model on the emission model is shown. In this paper, the abrasion wear model is compared to full-scale field measurements at several recently constructed roads in Sweden to investigate its validity, while also proposing changes to allow for continued use. It is concluded that the model overestimates the wear and an update is suggested. In addition, the impact on NORTRIP emission predictions is briefly investigated. There were also indications that NORTRIP is affected by the abrasion model overestimating the contribution of pavement wear to the particle emissions.