Abrasion Model Research Articles

Particle saltation trajectories in supercritical open channel flows: Roughness effect

AbstractBed load sediment transport governed by particle saltation in supercritical open channel flows causes bedrock incision in high‐gradient mountain streams and hydro‐abrasion at hydraulic structures. Hence, a better understanding of turbulent flow characteristics and particle dynamics is of prime importance for the prediction of river and landscape evolution, and for a sustainable design of hydraulic structures. To this end, we experimentally investigated single‐particle dynamics in supercritical open channel flows over fixed planar and abraded beds covering smooth, transitionally rough, and hydraulically rough regimes. The experiments were performed at the Laboratory of Hydraulics, Hydrology and Glaciology (VAW) of ETH Zürich in a wide range of hydraulic conditions with various channel width‐to‐depth aspect ratios (b/ho) and Froude numbers (F). We investigated the motions of five particle groups differing in shape, hardness, and diameter. By means of a high‐speed camera, the particle velocities and trajectory parameters—such as hop height and hop length—were determined using particle tracking velocimetry. The results reveal that at least 120 individual particles should be used in the tests to determine sound statistics of particle trajectories. In the present test conditions, the particles are dominantly transported in saltation. The effects of particle properties such as shape and diameter on the particle trajectories are negligible, while the rolling probability of the particles for a given flow condition increases with increasing diameter. Bed roughness was found to be the key parameter having a significant effect on the saltation trajectories and horizontal energy transfer. Hop height, hop length, and particle velocities, as well as horizontal energy transfer, increase with increasing bed roughness. Based on the saltation trajectory data, non‐dimensional equations are developed for each hydraulic regime and used to enhance the saltation–abrasion model of Sklar and Dietrich. The present findings contribute to a better understanding of particle motion characteristics under different hydraulic and roughness conditions, and their effect on the mechanics and prediction of bedrock incision and hydro‐abrasion in three‐dimensional supercritical open channel flows occurring in steeply sloped rivers and at hydraulic structures.

High-speed grinding fracture mechanism of Cf/SiC composite considering interfacial strength and anisotropy

Cf/SiC composite is connected through the bonding interface to achieve the toughening effect, which makes the fiber direction and interface strength in the material directly affect the composite properties and grinding quality. Aiming at the high-quality processing of Cf/SiC composite, a single abrasive particle model is built to reveal the variation law of grinding force in the process and the surface damage phenomena such as interface debonding, fiber fracture and matrix fracture. Based on the constitutive relationship among matrix, reinforcement and interface phase, the constitutive model of composite was established. However, Cf/SiC composite is a typical hard brittle material. Low grinding speed cannot yield to good machining quality. Thus, to improve the output quality, high speed grinding is applied in this paper. Meanwhile, by considering the heterogeneous structure characteristics of composite materials, the two-dimensional simulation of grinding of single abrasive particle grinding, based on FEM (Finite Element Model) method, is realized. Finally, composite fracture behavior is analyzed by observing microstructure in the grinding process. The effects of fiber orientation, surface strength, grinding speed, and grinding depth on the surface properties and the quality of Cf/SiC composite are studied by grinding force and surface analysis. The mechanism of high-speed grinding of ceramic matrix composites, as well as the practical approach and theoretical underpinnings of grinding process optimization, are examined.

Study on the CBN Wheel Wear Mechanism of Longitudinal-Torsional Ultrasonic-Assisted Grinding Applied to TC4 Titanium Alloy.

In this study, the CBN (cubic boron nitride) wheel wear model of TC4 titanium alloy in longitudinal-torsional ultrasonic-assisted grinding (LTUAG) was established to explore the grinding wheel wear pattern of TC4 titanium alloy in LTUAG and to improve the grinding efficiency of TC4 titanium alloy and the grinding wheel life. The establishment of the model is based on the grinding force model, the abrasive surface temperature model, the abrasive wear model, and the adhesion wear model of TC4 titanium alloy in LTUAG. The accuracy of the built model is verified by the wheel wear test of TC4 titanium alloy in LTUAG. Research has shown that the grinding force and grinding temperature in LTUAG increase with the increase of the grinding depth and workpiece feed rate and decrease with the increase of the longitudinal ultrasonic amplitude. It also shows that the grinding force gradually decreases with the increase of the grinding wheel speed, while the grinding temperature gradually increases with the increase of the grinding wheel speed. In addition, the use of LTUAG can significantly reduce the wear rate of the grinding wheel by 25.2%. It can also effectively reduce the grinding force and grinding temperature.

DEM Simulation in Wear Performance of Four Typical Bionic Structures

In order to resist the abrasion of sand and gravel, shellfish such as arca subcrenala lischke and arca inflata reeve have evolved non-smooth surface morphology with high wear resistance. In this paper, four biomimetic structures of prismatic, conical, ball crown and stripd were designed to study the abrasive wear behavior of different biomimetic structures. Built on the Discrete Element Method (DEM), the DEM model and its abrasive wear calculation model are established. By analyzing the changes of the contact bond field of the abrasive wear system, the non-uniform evolution process and wear law of the abrasive wear process of the four bionic structures are obtained. The research in this paper provides a new research method and means for the numerical simulation of wear behavior of biomimetic structures and the optimal design of biomimetic structures based on the surface morphology of biological non-smooth wear-resistant bodies.

Scoping Review: Evaluation of Moringa oleifera (Lam.) for Potential Wound Healing in In Vivo Studies.

Wound healing is a natural process to restore damaged tissues due to loss of tissue integrity. Moringa oleifera (locally known as merunggai in Malaysia) has been traditionally used in various ailments, including for wound management. To evaluate the wound healing properties in M. oleifera, publications were searched and selected following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement with predetermined inclusion criteria. The databases searched for primary studies include PubMed, Google Scholar, Science Direct, LILACS, ClinicalTrials.gov, and CENTRAL. In total, 18 in vivo studies were included, which involved the leaves, while the remaining 5 studies involved other plant parts tested on excision, incision, dead space, abrasion, and burn-induced wound models. All studies reported significant wound healing abilities. Most studies used different topical formulations of aqueous leaves extract. The accumulation of collagen content and underlying wound healing mechanism through antimicrobial, antioxidant, and anti-inflammatory activities may be contributed by its bioactive phytochemical content, which has the potential to accelerate the wound contraction, increase the rate of epithelialization, and protect tissues against oxidative damage. In conclusion, M. oleifera showed wound healing potential but further studies are warranted to determine the main bioactive phytocompounds and safety.

A mass abrasion model with the melting and cutting mechanisms during high-speed projectile penetration into concrete slabs

A mass abrasion model with the melting and cutting mechanisms during high-speed projectile penetration into concrete slabs

Combined treatment of xyloglucan derivative hydrogel and anti-C5a receptor antibody in preventing peritoneal adhesion

Postoperative peritoneal adhesion is a common complication after surgery with high morbidity. In addition to improving surgical operations, medical therapy and physical barriers are the two main ways to prevent postoperative peritoneal adhesion. Satisfactory efficacy is not often obtained by the single antiadhesion method, and the combination of barrier therapy and antiadhesion drugs has attracted more attention. In this study, we first demonstrated that aberrant complement activation was associated with peritoneal injury and inflammatory responses. Correspondingly, blocking the C5a-C5aR axis reaction effectively reduced inflammatory reactions. Therefore, we creatively developed an integrated treatment of xyloglucan derivative (mXG) hydrogel and intravenous anti-C5a receptor antibody (anti-C5aRab) aimed at peritoneal adhesion, and then systematically evaluated the therapeutic efficacy using a sidewall defect-cecum abrasion model in mice. In vitro and in vivo experiments showed that the mXG hydrogel had good biocompatibility and degradability and could serve as a safe anti-adhesion barrier. The results showed that anti-C5aRab treatment could significantly inhibit peritoneal adhesions by reducing neutrophil infiltration and the expression of phosphorylated Smad2. Taken together, the mXG hydrogel integrated with anti-C5aRab showed superior antiadhesion performance and holds promising clinical applications in preventing peritoneal adhesion. STATEMENT OF SIGNIFICANCE: Postoperative peritoneal adhesion is an urgent problem to be solved after surgery. Previously, a biodegradable and thermoreversible xyloglucan derivative (mXG) hydrogel was developed that effectively prevented postoperative peritoneal adhesions, but obvious inflammatory responses and proliferation could still be observed. In addition, aberrant complement activation is associated with a variety of inflammatory diseases. We demonstrated that aberrant complement activation is involved in peritoneal adhesion. In this work, mXG hydrogel and intravenous anti-C5a receptor antibody (anti-C5aRab) were integrated to address peritoneal adhesions. The anti-C5aRab reduced the inflammatory responses. In addition, the mXG hydrogel was easy to use and effectively isolated the wound surface at the local injury site. Overall, this integrated treatment significantly improved the antiadhesion effect.

Survival of the Strong and Dense: Field Evidence for Rapid, Transport‐Dependent Bed Material Abrasion of Heterogeneous Source Lithology

AbstractBed material abrasion is a major control on the partitioning of basin‐scale sediment fluxes between coarse and fine material. While abrasion is traditionally treated as an exponential function of transport distance and a lithology‐specific abrasion coefficient, experimental studies have demonstrated greater complexity in the abrasion process: the rate of abrasion varies with clast angularity, transport rate, and grain size. Yet, few studies have attempted to assess the importance of these complexities in a field setting. Here, we develop a new method for rapidly quantifying baseline abrasion rate in the field via Schmidt Hammer Rock Strength. We use this method, along with measurements of gravel bar lithology, to quantify abrasion in the Suiattle River, a basin in the North Cascades of Washington State in which sediment supply to the channel is dominated by recurrent debris flows from a tributary draining Glacier Peak stratovolcano. Rapid downstream strengthening of river bar sediment and a preferential loss of weak, low‐density vesicular volcanic clasts relative to non‐vesicular ones suggest that abrasion is extremely effective in this system. The standard exponential model for downstream abrasion, using single‐lithology abrasion rates fails to reproduce observed downstream patterns in lithology and clast strength. Incorporating heterogeneity in source material strength as well as transport rate‐dependent abrasion largely resolves this failure. Further work is needed to develop a comprehensive quantitative framework for the dependence of bed material abrasion on grain size and transport rate.

Modelling Particle Motion during High-Voltage Electrostatic Abrasive Implantation Based on Multi-Physics Field Coupling

Electrostatic abrasive implantation technology is a classical process based on electrostatic field to implant abrasive particles into base material. However, there is still not a quantitative model to ensure the implantation performance due to the fact that the electrostatic abrasive implantation is a complex multi-physics coupled process. To ensure the quality of sandpaper and elucidate the complex motion mechanism of Al2O3 based abrasive particles in a high voltage electrostatic field, a multi-physical field coupling simulation model is proposed. First, the mechanical model is constructed for the complex problem of the electrostatic abrasive implantation process. Then, the field model is established for the problem that the superposition of multi-physical fields leads to complicated environmental conditions. Finally, the evaluation model is established for the problems that the abrasive planting effect is difficult to evaluate and the planting parameters are difficult to adjust. Besides, a tailored electrostatic abrasive planting testing equipment is designed for the implantation performance analysis purpose. Single-parameter electrostatic abrasive planting experiments were conducted to analyze and verify the effect of different pole plate voltage and pole plate spacing on the abrasive implantation rate. To ensure the implantation performance, the applicable pole plate spacing ranges from 30 mm to 50 mm and the suitable voltage is 20–40 kV according to the simulation result in the proposed two models. Meanwhile, the implantation rate experimentation shows the coupling field model coincides with the experiments better. The key factors affecting the electrostatic abrasive planting process are identified, and a feasible multi-physical field coupled abrasive particle motion simulation model is proposed.

Photoinactivation of catalase sensitizes a wide range of bacteria to ROS-producing agents and immune cells.

Bacteria have evolved to cope with the detrimental effects of ROS using their essential molecular components. Catalase, a heme-containing tetramer protein expressed universally in most aerobic bacteria, plays an indispensable role in scavenging excess hydrogen peroxide (H2O2). Here, through use of wild-type and catalase-deficient mutants, we identified catalase as an endogenous therapeutic target of 400–420 nm blue light. Catalase residing inside bacteria could be effectively inactivated by blue light, subsequently rendering the pathogens extremely vulnerable to H2O2 and H2O2-producing agents. As a result, photoinactivation of catalase and H2O2 synergistically eliminated a wide range of catalase-positive planktonic bacteria and P. aeruginosa inside biofilms. In addition, photoinactivation of catalase was shown to facilitate macrophage defense against intracellular pathogens. The antimicrobial efficacy of catalase photoinactivation was validated using a Pseudomonas aeruginosa–induced mouse abrasion model. Taken together, our findings offer a catalase-targeting phototherapy approach against multidrug-resistant bacterial infections.

Hypothyroidism affects corneal homeostasis and wound healing in mice

PurposeThyroid hormones have a critical role in maintaining metabolic and physiological homeostasis. However, understanding of the possible effects of thyroid dysfunction on corneal homeostasis and the wound healing process is quite limited. To explore the influence of hypothyroidism on corneal homeostasis and the post-wound repair processes of the murine cornea. MethodsA hypothyroidism model was established by total thyroidectomy (TThy) in C57BL/6J mice. On day 10 after TThy, hypothyroidism was confirmed via thyronine (T3 and T4) and thyroid-stimulating hormone serum levels. We further assessed changes in corneal thickness, corneal sensitivity, sub-basal nerve density, and the corneal expression of thyroid hormone receptors. A corneal epithelial abrasion model was established via mechanical removal of a central epithelium 2 mm in diameter. Wound closure and recruitment of inflammatory cells (neutrophils and γδ T-cells) were evaluated. RNA-sequencing and gene set enrichment analysis were performed in injured corneas after abrasion. The effect of local T3 administration on corneal wound healing in thyroidectomized mice was also observed. ResultsCompared with sham-operated control mice, the TThy-treated mice showed the following: (1) a significant decrease in corneal epithelial thickness, sensitivity to external stimuli, and sub-basal nerve density, as well as an alteration in thyroid hormone receptor expression in the steady state; (2) delayed corneal wound repair and enhanced inflammatory response after corneal abrasion; (3) down-regulation of actin-skeleton and DNA replication pathways and up-regulation of inflammation-associated pathways in abraded corneas; and (4) significant restoration of delayed corneal wound repair and inhibition of excessive inflammation following topical T3 administration. ConclusionsWe conclude that deficient thyroid hormone secretion significantly affects corneal homeostasis and post-wound repair processes. Topical T3 administration might have a potential reversal effect on delayed corneal wound repair among hypothyroid individuals.

Simulation and Experimental Study on Abrasive Wear of Brake Discs

High-speed train brake discs are prone to abnormal wear in low temperature and heavy snow, which affects the safety of train operation. In this article, a staged braking strategy was proposed to improve the performance of train brake system in extremely cold climate by optimizing the relationship between operating speed and braking pressure. First, based on a brake bench test study, it was found that the average friction coefficient between the friction pairs increases significantly when the friction block holes were filled with quartz sand, and it was determined that the rigid particles introduced between the friction pairs at low temperatures are the direct cause of brake disc scratches. Then, a single abrasive wear model of the brake disc was established based on the Lagrangian finite-element method, and the damage characteristics of the brake disc under different braking modes were simulated and analyzed by the proposed model. The simulation results show that the braking mode with low speed and high pressure causes the most severe brake disc wear, which is consistent with the test results. According to the experiment and simulation results, the wear depth of the brake disc can be reduced by about 40% with the proposed staged braking strategy, which is of great significance to the safety of train operation in extremely cold weather.

An Injectable Peptide Hydrogel Constructed of Natural Antimicrobial Peptide J-1 and ADP Shows Anti-Infection, Hemostasis, and Antiadhesion Efficacy.

Postoperative adhesion is a common complication of abdominal surgery, which always has many adverse effects in patients. At present, there is still a lack of effective treatment measures and materials to prevent adhesion in the clinics. Herein, we report the potential use of J-1-ADP hydrogel formed by natural antimicrobial peptide jelleine-1 (J-1) self-assembling in adenosine diphosphate (ADP) sodium solution to prevent postsurgery adhesion formation. J-1-ADP hydrogel was found to have good antimicrobial activity against the bacteria and fungi tested and can be used to prevent tissue infection, which was thought to be one of the incitements of adhesion. Due to ADP being a platelet-activating factor, J-1-ADP hydrogel showed significant hemostatic activity in vitro verified by whole blood coagulation, plasma coagulation, platelet activation, and platelet adhesion assays. Further, it showed potent hemostatic activity in a mouse liver hemorrhage model. Bleeding was believed to be a cause of the formation of postsurgery adhesion. J-1-ADP hydrogel had a significant antiadhesion effect in a rat side wall defect-cecum abrasion model. In addition, it had good biocompatibility and degradation properties. So the present study may provide an alternative strategy for designing antimicrobial peptide hydrogel material to prevent postoperative adhesion formation in the clinic.

The protective and therapeutic effects of 5-androstene3β, 17β-diol (ADIOL) in abdominal post-operative adhesions in rat: Suppressing TLR4/NFκB/HMGB1/TGF1 β/α SMA pathway

Neurosteroid, 5-androstenediol (ADIOL) had been experimentally applied to protect against many diseases as it had anti-oxidant, anti-inflammatory, and anti-apoptotic effects. In our study, we investigate its role in abdominal postoperative adhesion (APA) formations. Our results demonstrate that ADIOL alleviates APA formation after induction by cecal abrasion (CA) model in the male rat. Interestingly, per administration of ADIOL before APA induction leads to inhibit oxidative stress by increasing superoxide dismutase (SOD) and decreasing Malondialdehyde (MAD) levels to a similar level to the sham group, in addition inhibiting inflammatory pathway by decreasing toll-like receptor 4 (TLR4), nuclear factor kappa-B (NFκB), and High mobility group box 1 (HMGB1) to a similar level to the sham group, furthermore decreasing Transforming growth factor beta 1 (TGFβ1) and alpha Smooth muscle -actin (α SMA) levels to similar levels in the sham group. While administration of ADIOL after APA induction lead to decrease adhesions formation by decreasing oxidative stress (↓MDA and ↑SOD levels), inflammatory markers (↓TLR4, ↓NFκB, and ↓HMGB1levels), and collagen deposition by (↓TGF1 β and↓α SMA levels) is the highly significant manner to those levels in CA model but also significant to those levels in the sham group. Concluded that, pre-administration of ADIOL before APA induction was more effective than its administration after adhesions formations.

N, O-carboxymethyl chitosan/oxidized cellulose composite sponge containing ε-poly-l-lysine as a potential wound dressing for the prevention and treatment of postoperative adhesion

Herein, we designed and fabricated a biodegradable composite sponge which main component contained N, O-carboxymethyl chitosan (N,O-CS) and oxidized cellulose nanocrystals (TOCN) as a potential wound dressing for the prevention and treatment of postoperative adhesion. In order to improve antimicrobial properties of N,O-CS/TOCN composite sponges, natural antimicrobial agents (ε-Poly-l-Lysine，EPL) were successfully introduced and the EPL/N,O-CS/TOCN composite sponge exhibited excellent antibacterial properties and biological security. The EPL/N,O-CS/TOCN composite sponge can be degraded in vivo within 3 weeks. Finally, we analyzed the anti-adhesion performance of EPL/N,O-CS/TOCN composite sponge through a rat model of sidewall defect-cecum abrasion. These results demonstrated that EPL/N,O-CS/TOCN-treated group can effectively reduce the peritoneal adhesion formation than the commercial soluble gauze group and normal saline group, which mainly attribute to the excellent hemostatic function and tissue repair function of EPL/N,O-CS/TOCN composite sponge. It is believed that the EPL/N,O-CS/TOCN composite sponge will prove to be as a new medical device treat the internal tissue/organ repair and simultaneous prevention of postoperative adhesion.

Numerical simulation of fluidized bed coating process considering particle abrasion

A coupled methodology was developed to model the fluidized bed coating process considering particle abrasion. Interactions of gas phase, particle phase and droplet phase were coupled with multiphase flow. Evaporation, coating and abrasion models were involved and verified by experimental data. The coupled method was evaluated by NaCl coating cases. Under the conditions of two experimental cases, quantitative proportion of the adhered precipitation abrased from the coated particle surface was obtained, which is attributed to frequent particle collisions. Another fluidized bed coating process, in-situ preparation of the Calcium-based supported sorbent for flue gas desulfurization, was simulated to validate the coupled model and investigate the effects of operating conditions on the net coating efficiency. When the nozzle was arranged near the dense phase zone, the conditions had little effect on the efficiency. Otherwise, higher efficiency can be achieved by increasing the bed inventory, droplet diameter, and droplet initial velocity. This research offers an efficient approach for modeling of fluidized bed coating process where particle abrasion is exigent, as well as providing guidelines for practical application of in-situ desulfurizer preparation.

The effect of topical decorin on temporal changes to corneal immune cells after epithelial abrasion

BackgroundCorneal immune cells interact with corneal sensory nerves during both homeostasis and inflammation. This study sought to evaluate temporal changes to corneal immune cell density in a mouse model of epithelial abrasion and nerve injury, and to investigate the immunomodulatory effects of topical decorin, which we have shown previously to promote corneal nerve regeneration.MethodsBilateral corneal epithelial abrasions (2 mm) were performed on C57BL/6J mice. Topical decorin or saline eye drops were applied three times daily for 12 h, 24 h, 3 days or 5 days. Optical coherence tomography imaging was performed to measure the abrasion area. The densities of corneal sensory nerves (β-tubulin III) and immune cells, including dendritic cells (DCs; CD11c+), macrophages (Iba-1+) and neutrophils (NIMP-R14+) were measured. Cx3cr1gfp/gfp mice that spontaneously lack resident corneal intraepithelial DCs were used to investigate the specific contribution of epithelial DCs. Neuropeptide and cytokine gene expression was evaluated using qRT-PCR at 12 h post-injury.ResultsIn decorin-treated corneas, higher intraepithelial DC densities and lower neutrophil densities were observed at 24 h after injury, compared to saline controls. At 12 h post-injury, topical decorin application was associated with greater re-epithelialisation. At 5 days post-injury, corneal stromal macrophage density in the decorin-treated and contralateral eyes was lower, and nerve density was higher, compared to eyes treated with saline only. Lower expression of transforming growth factor beta (TGF-β) and higher expression of CSPG4 mRNA was detected in corneas treated with topical decorin. There was no difference in corneal neutrophil density in Cx3cr1gfp/gfp mice treated with or without decorin at 12 h.ConclusionsTopical decorin regulates immune cell dynamics after corneal injury, by inhibiting neutrophils and recruiting intraepithelial DCs during the acute phase (< 24 h), and inhibiting macrophage density at the study endpoint (5 days). These immunomodulatory effects were associated with faster re-epithelialisation and likely contribute to promoting sensory nerve regeneration. The findings suggest a potential interaction between DCs and neutrophils with topical decorin treatment, as the decorin-induced neutrophil inhibition was absent in Cx3cr1gfp/gfp mice that lack corneal epithelial DCs. TGF-β and CSPG4 proteoglycan likely regulate decorin-mediated innate immune cell responses and nerve regeneration after injury.

Autonomic nervous system receptor-mediated regulation of mast cell degranulation modulates the inflammation after corneal epithelial abrasion

Mast cells (MCs) regulate wound healing and are influenced by the autonomic nervous system (ANS). However, the underlying mechanisms affecting wound healing outcomes remain elusive. Here, we explored the specific role of the ANS by regulating MC degranulation following corneal epithelium abrasion. A mouse model of corneal abrasion was established by mechanically removing a 2-mm central epithelium. Wound closure, neutrophil infiltration, and transcription of injured corneas were investigated using whole-mount immunostaining, flow cytometry, and RNA-sequencing analysis, respectively. Inhibition of MC degranulation by the MC stabilizers cromolyn sodium and lodoxamide tromethamine increased the infiltration of neutrophils and delayed healing of abraded corneas. Moreover, transcriptomic profiling analysis showed that purified MCs from the limbus expressed adrenergic and cholinergic receptors. Pharmacological manipulation and sympathectomy with 6-hydroxydopamine confirmed that sympathetic nervous system signaling inhibited MC degranulation after corneal abrasion, whereas parasympathetic nervous system signaling enhanced MC degranulation. We conclude that normal degranulation of MCs in the corneal limbus and crosstalk between the ANS and MCs are crucial for the appropriate control of inflammation and the repair progress of wounded corneas. This suggests a potential approach for improving defective corneal wound healing by the administration of clinically available autonomic activity-modulating agents.

Photoinactivation of Catalase Sensitizes Candida albicans and Candida auris to ROS-Producing Agents and Immune Cells.

Microbes have developed their own specific strategies to cope with reactive oxygen species (ROS). Catalase, a heme‐containing tetramer expressed in a broad range of aerobic fungi, shows remarkable efficiency in degrading hydrogen peroxide (H2O2) for fungal survival and host invasion. Here, it is demonstrated that catalase inactivation by blue light renders fungal cells highly susceptible to ROS attack. To confirm catalase as a major molecular target of blue light, wild type Candida albicans are systematically compared with a catalase‐deficient mutant strain regarding their susceptibility to ROS through 410 nm treatment. Upon testing a wide range of fungal species, it is found that intracellular catalase can be effectively and universally inactivated by 410 nm blue light. It is also found that photoinactivation of catalase in combination with ROS‐generating agents is highly effective in total eradication of various fungal species, including multiple Candida auris strains, the causative agent of the global fungal epidemic. In addition, photoinactivation of catalase is shown to facilitate macrophage killing of intracellular Candida albicans. The antifungal efficacy of catalase photoinactivation is further validated using a C. albicans‐induced mouse model of skin abrasion. Taken together, the findings offer a novel catalase‐photoinactivation approach to address multidrug‐resistant Candida infections.

Numerical Modeling of the Tuyere Surface Abrasion under Different Operating Conditions of Blast Furnace

The wear of tuyere in blast furnaces is a common problem in iron‐making production. One of the wear types is the abrasion caused by the impact of the coke and coal particles on the tuyere surface, which is also related to the hardness of the tuyere material. In this study, a computational fluid dynamics model is developed by considering pulverized coal injection, coke reaction, tuyere's heat transfer, and temperature affected hardness of the tuyere. With the obtained velocity field and temperature profiles, the heat transfer simulation with the particle abrasion model is applied on the tuyere surface to calculate the abrasive rate. The results indicated that the high temperature and severe abrasion occurred mostly on the tuyere's top surface for all simulated cases. The abrasive rate on the tuyere surface is around 5.2 × 10−6 kg (m2 s)−1, and the peak value reached 9.87 × 10−6 kg (m2 s)−1 under the operation condition of 0.26 oxygen concentration. The high‐temperature area on the tuyere surface is a key factor that affects the abrasive rate. The statistical analysis showed that the area of the temperature over 1000 K can reach nearly 30% for 0.26 oxygen concentration, while this area is less than 10% without oxygen enrichment.