The dry sliding wear behaviour of different Ti-Nb and Ti-Mo surfaces was investigated in order to evaluate the role of Nb and Mo β-stabilizing elements in titanium wear resistance to consider them ...for biomedical applications. Dry sliding wear tests were performed under unlubricated conditions using a ball-on-plate tribometer (UMT) with reciprocating lineal movement of 1 Hz frequency at different loads (2 and 5 N) and against two counterface materials (alumina and stainless steel) to assess the effect of these parameters on wear. The results indicated an improvement in wear resistance for all the modified Ti surfaces. Metal-on-metal surfaces exhibited higher wear rate than ceramic-on-metal, and higher wear was observed for the more severe conditions. Wear rate values on modified surfaces were between 53% and 96% lower compared to pure Ti tested at 2 N, and up to 79% lower than Ti at 5 N. In both cases the highest wear reduction was observed for Ti-Mo
surface.
•Effect of Nb and Mo diffusion treatments in Ti corrosion and tribocorrosion behaviour.•β-Ti gradient surfaces with Young’s modulus closer to that of bone exhibited better anticorrosive properties ...than cp-Ti.•These Ti surfaces with Nb or Mo presented lower tendency to corrosion under tribological action.•The Mo + NH4Cl diffusion resulted in the hardest surface with the best tribocorrosion behaviour.
Corrosion and tribocorrosion behaviour of modified Ti surfaces through thermochemical treatments has been studied. Electrochemical Impedance Spectroscopy (EIS) and reciprocating sliding tests using a ball-on-plate tribometer under 1 N load and alumina as counter-material were used to evaluate the influence of Nb and Mo on titanium corrosion and tribocorrosion properties.
Ti-Nb and Ti-Mo surfaces exhibited better anticorrosive properties than CP-titanium. Under tribological action the modified Ti surfaces showed similar coefficient of friction and lower tendency to corrosion compared to CP-Ti. Furthermore, Nb diffusion increased the repassivation rate with respect to Ti and Ti-Mo surfaces due to its stable passive film.
This work focuses on the bioactivity and biological response of modified Ti surfaces produced by powder metallurgy. They are processed by diffusion of two β-stabilizing elements, Nb and Mo, deposited ...onto the surface of PM Ti substrates. Moreover, the addition of an activating agent, NH4Cl, to the suspension has been carried out by thermo-reactive diffusion process. The surface modification led to a gradient in composition (Ti-Nb or Ti-Mo) and microstructure (β/α+β/α phases). This work presents the bioactivity results of these Ti-Mo and Ti-Nb surfaces as well as the cell-material response of the Ti-Nb surfaces. The reactivity of the materials was tested through immersion in simulated body fluid considering Ca and P precipitation in order to assess the ability of the materials to induce hydroxyapatite formation. The in-vitro cell response was evaluated by human osteoblast-like cells incubation on the different surfaces for 48h. The investigation led to positive results in terms of surface bioactivity and an improved cell-material interaction of the PM modified Ti-Nb surfaces compared to the reference Ti material.
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•The surface modification of Ti by Mo or Nb diffusion processes decrease elastic modulus and enhance bioactivity.•Ti surfaces modified with Mo and Nb show ability for hydroxyapatite formation without additional pre-treatments to promote it.•Improved cell-material interaction of the different Ti-Nb surfaces designed compared to Ti.
Objective
To compare the efficacy of infliximab (IFX) versus adalimumab (ADA) as a first‐line biologic drug over 1 year of treatment in a large series of patients with refractory uveitis due to ...Behçet's disease (BD).
Methods
We conducted an open‐label multicenter study of IFX versus ADA for BD‐related uveitis refractory to conventional nonbiologic treatment. IFX or ADA was chosen as the first‐line biologic agent based on physician and patient agreement. Patients received 3–5 mg/kg intravenous IFX at 0, 2, and 6 weeks and every 4–8 weeks thereafter, or 40 mg subcutaneous ADA every other week without a loading dose. Ocular parameters were compared between the 2 groups.
Results
The study included 177 patients (316 affected eyes), of whom 103 received IFX and 74 received ADA. There were no significant baseline differences between treatment groups in main demographic features, previous therapy, or ocular sign severity. After 1 year of therapy, we observed an improvement in all ocular parameters in both groups. However, patients receiving ADA had significantly better outcomes in some parameters, including improvement in anterior chamber inflammation (92.31% versus 78.18% for IFX; P = 0.06), improvement in vitritis (93.33% versus 78.95% for IFX; P = 0.04), and best‐corrected visual acuity (mean ± SD 0.81 ± 0.26 versus 0.67 ± 0.34 for IFX; P = 0.001). A nonsignificant difference was seen for macular thickness (mean ± SD 250.62 ± 36.85 for ADA versus 264.89 ± 59.74 for IFX; P = 0.15), and improvement in retinal vasculitis was similar between the 2 groups (95% for ADA versus 97% for IFX; P = 0.28). The drug retention rate was higher in the ADA group (95.24% versus 84.95% for IFX; P = 0.042).
Conclusion
Although both IFX and ADA are efficacious in refractory BD‐related uveitis, ADA appears to be associated with better outcomes than IFX after 1 year of follow‐up.
In this work, a cellulose acetate butyrate (CAB) and polyethylene glycol (PEG) blend is used as the binder system in a zirconium silicate mineral powder feedstock for powder injection moulding. These ...irregular zircon powders make the mixing process and the selection of an optimal solid loading level a difficult task. Torque rheology methodologies combined with other techniques are used for evaluation of the parameters affecting the mixing process and determination of the critical powder volume concentration (CPVC). Temperature variations during the mixing process are monitored and used as an indicator of the friction energy of the system and thus for the optimal solid loading selection. There have thus far been limited amounts of work conducted on torque rheology of highly loaded feedstocks that incorporate a study of the system's temperature evolution. A detailed study could be a key factor for understanding the mixing behaviour of highly loaded feedstocks.
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•Sol-gel coatings have been modified with dimethyltrimethylsilylphosphite, DMPTMS.•DMPTMS acts as a phosphorous precursor and cross-linking agent.•DMPTMS increases the rate of ...intermolecular condensation within the coating.•DMPTMS enhances osteoblast biocompatibility and corrosion resistance of coating.
The durability and long-term success of metallic implants are enhanced through the molecular scale design of biocompatible and corrosion resistant surface coatings. To pursue this hypothesis, we have developed a new class of organic-inorganic (O-I) hybrid nanocomposite coatings based on tetramethylorthosilicate (TMOS) and γ-methacryloxypropyltrimethoxysilane (MAPTMS) as organofunctional alkoxysilanes precursors and dimethyltrimethylsilylphosphite (DMTMSP) as a phosphorus precursor. Addition of DMTMSP to TMOS-MAPTMS hybrids increased the extent of intermolecular condensation and cross-linking observed. Both normal human osteoblast in-vitro biocompatibility and corrosion resistance were enhanced in coatings containing DMTMSP. Though increasing phosphorous content correlated with biocompatibility, a compromise in the amount of phosphorus incorporated would be required if corrosion resistance was the most desirable parameter for optimization, at least for single coat systems. Evaluation of the electrochemical behaviour and the in-vitro biocompatibility show that films prepared using these materials by dip coating onto Ti6Al4V alloys offer a promising alternative to simpler coatings and wholly metallic prostheses.
The sterilization processes of nanoparticles (NP) by autoclaving and filtration are two of the most utilized methods in the pharmaceutical industry but are not always a viable option. For this ...reason, the search for alternative options such as UV and gamma radiation is of interest. In this work, we evaluated both types of sterilization on two types of NP in solid state widely employed in the literature for biomedical applications, poly-(ε-caprolactone) and poly(D, L-lactide-co-glycolide) acid NP stabilized with polyvinyl alcohol. Physicochemical properties and cell viability were studied pre- and post-sterilization. The efficiency of irradiation sterilization was performed by a test of sterility using 1 × 10
CFU/mL of Escherichia coli, Staphylococcus aureus, and Candida albicans. Microbiological monitoring revealed that both methods were sufficient for sterilization. After the UV irradiation sterilization (100 µJ/cm
), no substantial changes were observed in the physicochemical properties of the NP or in the interaction or morphology of human glial cells, though 5 and 10 kGy of gamma irradiation showed slight changes of NP size as well as a decrease in cell viability (from 100 µg/mL of NP). At 5 kGy of radiation doses, the presence of trehalose as cryoprotectant reduces the cell damage with high concentrations of NP, but this did not occur at 10 kGy. Therefore, these methods could be highly effective and low-processing-time options for sterilizing NP for medical purposes. However, we suggest validating each NP system because these generally are of different polymer-composition systems.
•Simple halide treatment with NH4Cl was carried out on Ti6Al4V alloy.•High temperature oxidation and electrochemical corrosion were evaluated.•Improvement in high temperature oxidation resistance was ...observed.•Improvement in corrosion resistance was observed for samples treated at 200°C.
The aim of this work is to study the effect of halide treatment in powder metallurgy Ti–6Al–4V alloy, in order to improve high temperature oxidation and electrochemical corrosion resistance. Halide treatment was performed by immersing samples in a powder mixture containing 3wt% NH4Cl, at 200°C and 950°C. Oxidation resistance was assessed by exposure to 600°C for 300h. The microstructure and phase constitution of the formed oxide layers was characterized. Corrosion resistance in aircraft simulated environment was evaluated with electrochemical impedance spectroscopy. Notable improvement in oxidation and corrosion resistance was observed for samples treated at 200°C.
Summary
Alternative strategies are required to enhance the diagnosis of silent hepatitis C virus (HCV) infections in key populations at risk. Among them, HCV prevalence and bio‐behavioural data are ...scarce for HIV‐negative men who have sex with men (MSM) and men and trans‐women sex workers. We sought to describe and assess the potential benefits of a community‐based one‐step HCV screening and confirmatory strategy for these populations in Barcelona. The screening strategy based on a real‐time RT‐PCR assay for HCV‐RNA detection in dried‐blood spots (DBS) was validated and implemented in addition to an antibody point‐of‐care test in a community centre. HCV prevalence was assessed, and bio‐behavioural data were collected. The molecular assay was precise, reproducible, sensitive and specific. Four HIV‐negative MSM reported being currently infected (0.75% HCV self‐reported prevalence). Implementation of DBS testing was easy, and acceptability was >95%, but no silent HCV case was diagnosed (N = 580). High‐risk sexual practices and drug use for sex were reported frequently. HIV prevalence was 4.7% in MSM and 10% in sex workers. Self‐reported prevalence of other STIs ranged from 11.3% to 36.2%. In conclusion, HCV‐RNA testing in DBS showed a good performance, but the assessed one‐step strategy does not seem beneficial in this setting. Although no silent HCV infections were detected, the observed high‐risk behaviours and prevalence of other STIs suggest that HCV spread should be periodically monitored among these populations in Barcelona by means of behavioural surveillance, rapid antibody testing and molecular confirmation in DBS.
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