Where the infection is isolated rather than the specific species correlates with adherence strength, whereas biofilm density remains static in clinically isolated Candida and arthroconidial yeasts

To colonize and infect the host, arthroconidial yeasts must avoid being killed by the host’s defenses. The formation of biofilms on implanted devices allows fungi to avoid host responses and to disseminate into the host. To better study the mechanisms of infection by arthroconidial yeasts, adherence and biofilm formation were assayed using patient samples collected over 10 years. In clinical samples, adherence varies within species, but the relative adherence is constant for those samples isolated from the same infection site. Herein we document, for the first time, in-vitro biofilm formation by Trichosporon dohaense, T. ovoides, T. japonicum, T. coremiiforme, Cutaneotrichosporon mucoides, Cutaneotrichosporon cutaneum, Galactomyces candidus, and Magnusiomyces capitatus on clinically relevant catheter material. Analysis of biofilm biomass assays indicated that biofilm mass changes less than 2-fold, regardless of the species. Our results support the hypothesis that most pathogenic fungi can form biofilms, and that biofilm formation is a source of systemic infections.

Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls

One of the main functions of renders, together with the overall aesthetic appearance of the building, is the protection of the walls against external aggressive actions, such as water, salts solutions, erosion, and mechanical impacts. However, some anomalies of renders may drastically hinder their protection ability. In fact, cracking, high water permeability, and loss of adherence to the substrate of renders limit their barrier effect and favour the exposure of the substrate to external actions. The incorporation of fibres in mortars is commonly pointed out to reduce their cracking susceptibility, due to the probable enhancement in tensile strength and ductility of the composite. The use of lime in substitution of the part of the cement binder is seen as a method to reduce the modulus of elasticity and therefore enhance the resistance to cracking due to drying shrinkage. Therefore, this study investigates the wall protection-related properties of natural fibre-reinforced renders with cement-lime as a binary binder at 1:1:6 volumetric ratio. With this purpose, wool, coir, and flax fibres are used at 20% by total mortar volume and the water behaviour, cracking susceptibility, and adherence to the substrate of the mortars are assessed. Specifically, the water absorption by capillarity, drying rates, permeability to water under pressure, adherence strength, and shrinkage are evaluated. In order to evaluate the renders’ durability and therefore the durability of the protection to the walls, an artificial accelerated ageing test is performed based on heating-freezing and humidification-freezing cycles. The results indicate that the fibres’ addition reduced the shrinkage and modulus of elasticity of the mortars, which suggests lower susceptibility to cracking. The addition of fibres in mortars seemed to slightly affect their water performance and only at early ages. From the results, it was concluded that the adherence strength is not affected by the fibres’ incorporation. The fibres seem also to reduce the impacts of the ageing cycles on the mortar and the improvements provided by the fibres’ addition to the mortars’ performance remained after ageing when compared to the mortars without fibres, thus being a potential alternative to increase their durability. These aspects are particularly important for buildings, since they can extend their service life and promote their sustainability.

Adherence Kinetics of a PDMS Gripper with Inherent Surface Tackiness

Damage and fibre misalignment of woven fabrics during discontinuous polymer processing remain challenging. To overcome these, a promising switchable elastomeric adherence gripper is introduced here. The inherent surface tackiness is utilized for picking and placing large sheets. Due to the elastomer’s viscoelastic material behavior, the surface properties depend on loading speed and temperature. Different peeling speeds result in different adherence strength of an interface between the gripper and the substrate. This feature is mechanically characterized and the viscoelastic behavior of the stamp is examined. Based on this experimental characterization, an empirical model is proposed. Furthermore, a discussion of the applicability and limitation of the elastomeric gripper is given.

Mechanical and tribological properties of Cr/Cr2O3 multilayer films

Cr/Cr2O3 multilayer and single-layer films were deposited through multiple arc ion plating technique. The influence of modulation ratio on the mechanical and tribological properties was also investigated. Results show that the multilayer design of Cr/Cr2O3 films could improve the toughness of films, but a certain degree of hardness loss is also observed. The hardness and adherence strength are improved with the increase of Cr2O3 layer thickness. Furthermore, alternating layers of ductile soft metals and hard ceramics could suppress the propagation of microcracks and brittle fracture. However, the decrease of modulation ratio could causes a decline in the mechanical properties. The film with appropriate modulation ratio (Cr2O3:Cr ratio 10:1) exhibits better comprehensive properties than other films, this film also exhibits an excellent wear resistance with a high load of 10 N. Consequently, the wear life is improved from 6 m of the single-layer Cr2O3 film to 835 m of the multilayer film.

Effects of a Fibrin Sealant on Skin Graft Tissue Adhesion in a Rodent Model

Objective To establish a rodent model for skin grafting with fibrin glue and examine the effects of fibrin glue on the adhesive strength of skin grafts without bolsters. Study Design Animal cohort. Setting Academic hospital laboratory. Subjects and Methods Three skin grafts were created using a pneumatic microtome on the dorsum of 12 rats. Rats were evenly divided into experimental (n = 6) and control (n = 6) groups. The experimental group received a thin layer of fibrin glue between the graft and wound bed, and the control group was secured with standard bolsters. Adherence strength of the skin graft was tested by measurement of force required to sheer the graft from the recipient wound. Adhesion strength measurements were taken on postoperative days (PODs) 1, 2, and 3. Results The experimental group required an average force of 719 g on POD1, 895 g on POD2, and 676 g on POD3, while the average force in the control group was 161 g on POD1, 257 g on POD2, and 267 g on POD3. On each of the 3 PODs, there was a significant difference in adherence strength between the experimental and control groups ( P = .036, P = .029, P = .024). Conclusion There is a significant difference in the adhesion strength of skin grafts to the wound bed in the early postoperative period of the 2 groups. In areas of high mobility, using the fibrin sealant can keep the graft immobile during the critical phases of early healing.

Evaluation of Incorporation of a Leather Waste Powder in Mortars for Construction Industry

This paper has the objective to evaluate the technical feasibility of incorporation of leather powder in mortars. First a physical characterization of aggregate was carried and then preceded to the dissolution of the leather powder in alkaline solution, in the proportion of 1:1:1 of waste, alkaline solution and water respectively, obtaining the processed waste. In the next step, it has been molded specimen using two reference recipes in terms of mass, 1:3 of cement and sand, and 1:1:6 of cement, hydrated lime and sand respectively, keeping constant the flow table consistency of 130 ±10 mm and 220±10 mm, for each respectively recipe. Two groups of mortars were produced: one without processed waste, one with 5% and one with 10% in ratio to the cement mass. Tests had been carried such as compressive strength to axial compression, tensile strength to diametrical compression, and adherence strength on surfaces. The resistance tests performed; also the analyses of the leachate and solubilized extracts confirmed the feasibility of incorporation of leather powder in mortars.

Evaluation of the Thermally Sprayed Cermet Coatings Adhesion by Scratch Test

The paper presents a study regarding the evaluation of the adherence strength using scratch test of WC 12%Co coating deposited by high velocity oxygen fuel (HVOF) method onto the surface of a carbon steel substrate.The coating morphology was characterized by scanning electron microscopy (SEM).The scratching process of the WC Co coating was controlled and monitored using a Millennium 200 Technical Tribo equipment, the test being performed according to DIN EN 1071-3 Standard. The load required to cause the failure of the WC Co coating on the carbon steel substrate was determined. The points where the coating fails by cracking are taken as critical failure points.