Growth of Anodic Layers on 304L Stainless Steel Using Fluoride Free Electrolytes and Their Electrochemical Behavior in Chloride Solution.

Anodic layers have been grown on 304L stainless steel (304L SS) using two kinds of fluoride-free organic electrolytes. The replacement of NH4F for NaAlO2 or Na2SiO3 in the glycerol solution and the influence of the H2O concentration have been examined. The obtained anodic layers were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and potentiodynamic polarization tests. Here, it was found that, although the anodic layers fabricated within the NaAlO2-electrolyte and high H2O concentrations presented limited adherence to the substrate, the anodizing in the Na2SiO3-electrolyte and low H2O concentrations allowed the growth oxide layers, and even a type of ordered morphology was observed. Furthermore, the electrochemical tests in chloride solution determined low chemical stability and active behavior of oxide layers grown in NaAlO2-electrolyte. In contrast, the corrosion resistance was improved approximately one order of magnitude compared to the non-anodized 304L SS substrate for the anodizing treatment in glycerol, 0.05 M Na2SiO3, and 1.7 vol% H2O at 20 mA/cm2 for 6 min. Thus, this anodizing condition offers insight into the sustainable growth of oxide layers with potential anti-corrosion properties.

Influence of exposure time on the release of bacteria from a biofilm on Ti6Al4V discs using sonication: An in vitro model.

Implant sonication is considered a useful method for the diagnosis of implant-related infections. We designed an in vitro study using Ti6Al4V discs and 5 different bacteria to determine the optimal sonication time for recovery of most bacteria tested to enable use of sonication in clinical practice for microbiological diagnosis of implant-related infections. We carried out a specific protocol for the adherence and subsequent biofilm formation on the materials used. The discs were then sonicated and the retrieved bacteria were quantified. From minute 1 to 5, the amount of recovered organisms grew progressively for all bacteria. Between minute 6 and minute 10, the number was irregular for all strains except E. coli, though no pattern was evidenced. E. coli was the only microorganism with a progressive increase in liberation throughout the process. Significant differences were observed in each of the 10minutes analyzed as concerns the release of the 5 strains (P<0.021) as well as in the mean dislodgement (of the 10minutes) of all tested strains (P<0.00001). Considering that infections in which biofilms are involved could be polymicrobial, we concluded that 5minutes is the optimal time of sonication in order to recover the maximum amount of most bacteria attached to Ti6Al4V discs.

Referencias argentinas para la evaluación de proporciones corporales desde el nacimiento hasta los 17 años / Argentine references for the assessment of body proportions from birth to 17 years of age

Introducción. La alteración de las proporciones corporales puede ser indicativa de enfermedad esquelética, por lo cual su detección resulta de gran utilidad clínica. Objetivos. Estimar los centilos de los índices perímetro cefálico/estatura (PC/E) y estatura sentada/estatura (ES/E), y evaluar su utilidad diagnóstica en un grupo de niños con displasia esquelética. Métodos. Los centilos 3, 10, 25, 50, 75, 90 y 97 de ES/E y PC/E fueron estimados por el método LMS, que utiliza la transformación Box-Cox para normalizar la distribución de los datos a cada edad. Se aplicaron los tests Q-Q plot para evaluar la normalidad de los residuos y el Q test para evaluar la bondad de ajuste. Resultados. La muestra incluyó 4818 niñas y 4803 niños sanos de 0 a 17 años de edad. La mediana del índice ES/E para la edad cayó desde valores de 0,67 al nacer hasta 0,57 a los 4 años. A los 12 años, alcanzó valores de 0,52 y 0,53 para varones y mujeres, respectivamente, y se mantuvo así hasta los 17 años de edad. La mediana del índice PC/E cayó desde 0,45 a los 6 años hasta 0,34 a los 17 años de edad en ambos sexos. Los puntajes Z del ES/E en 20 niños con diagnóstico de hipocondroplasia mostraronmejor la desproporción corporal que la utilización del índice ES/E no ajustado por edad. Conclusiones. Los centilos estimados de PC/E y ES/E muestran que, en el período prepuberal, ocurren los mayores cambios en las proporciones corporales. Estas referencias facilitan una detección más temprana de desproporción corporal en niños con displasia esquelética.

Introduction. Abnormal body proportions may indicate skeletal disorders; therefore, their detection has great clinical significance. Objectives.To estimate centiles for head circumference/height (HC/H) and sitting height/height (SH/H) ratios, and assess their diagnostic usefulness among a group of children with skeletal dysplasia. Methods. Centiles 3, 10, 25, 50, 75, 90 and 97 for HC/H and SH/H ratios were estimated with the LMS method using Box-Cox transformation to normalize data distribution for each age. Q-Q plot tests were applied to evaluate normality of residuals and the Q test to calculate goodness-of-fit. Results. The sample included 4818 girls and 4803 boys, all healthy, between 0-17 years old. The median of the SH/H ratio for each age decreased from 0.67 at birth to 0.57 at age 4. At 12 years of age, values reached 0.52 and 0.53 for males and females, respectively, remaining unchanged until age 17. The median of the HC/H ratio decreased from 0.45 at 6 years old to 0.34 at 17 years old for both sexes. Z-scores for SH/H among 20 children diagnosed with hypochondroplasia were better at showing abnormal proportions than the SH/H ratio not adjusted by age. Conclusions.Estimated centiles for HC/H and SH/H ratios show that the most dramatic changes in body proportions occur in the prepubertal period. These references allow an earlier detection of abnormal body proportions in children with skeletal dysplasia.

Argentine references for the assessment of body proportions from birth to 17 years of age. / Referencias argentinas para la evaluación de proporciones corporales desde el nacimiento hasta los 17 años.

INTRODUCTION: Abnormal body proportions may indicate skeletal disorders; therefore, their detection has great clinical significance. OBJETIVES: To estimate centiles for head circumference/height (HC/H) and sitting height/height (SH/H) ratios, and assess their diagnostic usefulness among a group of children with skeletal dysplasia. METHODS: Centiles 3, 10, 25, 50, 75, 90 and 97 for HC/H and SH/H ratios were estimated with the LMS method using Box-Cox transformation to normalize data distribution for each age. Q-Q plot tests were applied to evaluate normality of residuals and the Q test to calculate goodness-of-fit. RESULTS: The sample included 4818 girls and4803 boys, all healthy, between 0-17 years old. The median of the SH/H ratio for each age decreased from 0.67 at birth to 0.57 at age 4. At 12 years of age, values reached 0.52 and 0.53 for males and females, respectively, remaining unchanged until age 17. The median of the HC/H ratio decreased from 0.45 at 6 years old to 0.34 at 17 years old for both sexes. Z-scores for SH/H among 20 children diagnosed with hypochondroplasia were better at showing abnormal proportions than the SH/H ratio not adjusted by age. CONCLUSIONS: Estimated centiles for HC/H and SH/H ratios show that the most dramatic changes in body proportions occur in the prepubertal period. These references allow an earlier detection of abnormal body proportions in children with skeletal dysplasia.

INTRODUCCIÓN: La alteración de las proporciones corporales puede ser indicativa de enfermedad esquelética, por lo cual su detección resulta de gran utilidad clínica. OBJETIVOS: Estimar los centilos de los índices perímetro cefálico/estatura (PC/E) y estatura sentada/estatura (ES/E), y evaluar su utilidad diagnóstica en un grupo de niños con displasia esquelética. MÉTODOS: Los centilos 3, 10, 25, 50, 75, 90 y 97 de ES/E y PC/E fueron estimados por el método LMS, que utiliza la transformación Box-Cox para normalizar la distribución de los datos a cada edad. Se aplicaron los tests Q-Q plot para evaluar la normalidad de los residuos y el Q test para evaluar la bondad de ajuste. RESULTADOS: La muestra incluyó 4818 niñas y 4803 niños sanos de 0 a 17 años de edad. La mediana del índice ES/E para la edad cayó desde valores de 0,67 al nacer hasta 0,57 a los 4 años. A los 12 años, alcanzó valores de 0,52 y 0,53 para varones y mujeres, respectivamente, y se mantuvo así hasta los 17 años de edad. La mediana del índice PC/E cayó desde 0,45 a los 6 años hasta 0,34 a los 17 años de edad en ambos sexos. Los puntajes Z del ES/E en 20 niños con diagnóstico de hipocondroplasia mostraronmejor la desproporción corporal que la utilización del índice ES/E no ajustado por edad. CONCLUSIONES: Los centilos estimados de PC/E y ES/E muestran que, en el período prepuberal, ocurren los mayores cambios en las proporciones corporales. Estas referencias facilitan una detección más temprana de desproporción corporal en niños con displasia esquelética.

Influence of the nanostructure of F-doped TiO2 films on osteoblast growth and function.

The aim of this study was to evaluate the proliferation and mineralization ability of mouse osteoblastic MC3T3-E1 cells on F-containing TiO2 films with different morphology and nanostructure that previously confirmed antibacterial properties. F-containing TiO2 films were fabricated by anodizing Ti-6Al-4V alloy ELI -grade 23. By using a mixture of H2SO4/HF acid at 20 V for 5 and 60 min, a TiO2 film grows with nanoporous (NP) and nanotubular (NT) features, characterized with a pore diameter of 20 and 100 nm, respectively. Fluoride-TiO2 barrier films (FBL) were produced in 1M NH4H2PO4/0.15M NH4F solution at constant voltage controlled at 20 V for 120 min. The amount of F incorporated in the nanostructured oxide films was 6 at % and of 4 at %, for the NP and NT, respectively, while for the FBL film was 12 at %. MC3T3-E1 cells exhibited different behavior when seeded and grown onto these surfaces. Thus, F-doped TiO2 films with NP structures increased proliferation as well as osteogenic gene expression and the mineralization capacity of these osteoblastic cells. These results confirm that anodizing process is suitable to fabricate multifunctional surfaces on Ti-6Al-4V alloy with improved not only antibacterial but also osteogenic properties useful for bone fixation of prosthetic devices

Anodization Mechanism on SiC Nanoparticle Reinforced Al Matrix Composites Produced by Power Metallurgy.

Specimens of aluminum-based composites reinforced by silicon carbide nanoparticles (Al/SiCnp) produced by powder metallurgy (PM) were anodized under voltage control in tartaric-sulfuric acid (TSA). In this work, the influence of the amount of SiCnp on the film growth during anodizing was investigated. The current density versus time response and the morphology of the porous alumina film formed at the composite surface are compared to those concerning a commercial aluminum alloy (AA1050) anodized under the same conditions. The processing method of the aluminum alloys influences the efficiency of the anodizing process, leading to a lower thicknesses for the unreinforced Al-PM alloy regarding the AA1050. The current density versus time response is strongly dependent on the amount of SiCnp. The current peaks and the steady-state current density recorded at each voltage step increases with the SiCnp volume fraction due to the oxidation of the SiCnp. The formation mechanism of the anodic film on Al/SiCnp composites is different from that occurring in AA1050, partly due the heterogeneous distribution of the reinforcement particles in the metallic matrix, but also to the entrapment of SiCnp in the anodic film.

Doped TiO2 anodic layers of enhanced antibacterial properties.

Ti-6Al-4V joint replacement implants foster uncemented fixation in orthopaedic surgery. However, bacterial colonization competes with host cells and ultimately may produce implant-related difficult-to-treat infections, justifying the efforts to obtain infection-resistant materials. In a previous work, the authors demonstrated the antibacterial properties of anodic fluoride-TiO2 nanostructured layers on Ti-6Al-4V alloy. In this work, the anodizing bath has been modified in order to grow fluoride-TiO2 barrier layers (FBL). A bacterial adherence protocol, run with reference and six different clinical strains of Staphylococcus aureus and Staphylococcus epidermidis, showed a statistically significant decrease in the percentage of covered surface (p<0.0001, Kruskal-Wallis test) for FBL specimens when compared with non fluoride-containing specimens, i.e. chemically polished Ti-6Al-4V and F-free TiO2 barrier layers. The results obtained on the F-barrier layers allowed discrimination between the effects of the presence of fluoride in the layer and the layer nanostructure on bacterial adhesion.

In vitro assessment of Staphylococcus epidermidis and Staphylococcus aureus adhesion on TiO2 nanotubes on Ti-6Al-4V alloy.

The aim of this study was to evaluate Staphylococcus sp. adhesion to modified surfaces of titanium alloy (Ti-6Al-4V). Specimens of Ti-6Al-4V alloy 6-4 ELI-grade 23 that meets the requirements of ASTM F136 2002A (AMS 2631B class A1) were anodized in a mixture of sulfuric/hydrofluoric acid at 20 V for 5 and 60 min to form nanoporous (NP) and nanotubular (NT) oxide layers with pore diameter of 20 and 100 nm, respectively. The amount of fluorine incorporated in the oxide films from the electrolyte was 6 and 4 wt %, respectively. Bacterial adherence was studied using laboratory strains and six clinical strains each of Staphylococcus aureus and Staphylococcus epidermidis. Lower adherence of laboratory strains was demonstrated on fluoride nanostructured surfaces in comparison with the fluoride-free surfaces. Significant differences between clinical strains and laboratory strains were also found (p < 0.0001, Kruskal-Wallis test) when NP and NT specimens were compared with chemically polished (CP) surfaces. The results of the tests using multiple clinical strains confirmed a decrease in bacterial adherence on F-containing titanium oxide surfaces, suggesting a potential applicability of this surface, with a confirmed added value of decreasing clinical staphylococci adherence, for medical prosthetic devices.

[Prevalence of indirect sharing of drug-injecting paraphernalia in Galicia, Madrid, Seville and Valencia [Spain]]. / Prevalencia de prácticas indirectas de compartir material para inyectarse drogas en Galicia, Madrid, Sevilla y Valencia.

OBJECTIVES: To study drug-injecting practices, particularly indirect sharing of injecting paraphernalia (ISIP), and sexual risk behavior. METHODS: We performed a cross-sectional study of 1638 users of needle exchange programs (NEPs). Different types of ISIP were studied: taking diluted drugs in a syringe used by others, placing the needle in a recipient with other used needles, and reusing cleaning liquid previously used by others. RESULTS: The prevalence of injecting with syringes already used by others was 16% in Galicia, 4.7% in Madrid, 17.6% in Seville and 13.2% in Valencia (p < 0.001). With geographical variations, other types of ISIP (Galicia: 32.4%; Madrid: 28.5%; Seville: 42.6%; Valencia: 27.4% -p < 0.001-) were more frequent than injecting with syringes already used by others (Galicia: 32.4%; Madrid: 28.5%; Seville: 42.6%; Valencia: 27.4% -p < 0.001-). The percentage not injecting with syringes used by others but performing ISIP was 21.7%, 25.3%, 28.2% and 18.1% (p < 0.01) respectively. In all geographical areas, sexual risk practices were more prevalent with steady sex partners (68.6%, 72.0%, 77.8%, 72.8% [NS]) than with casual partners (36.6%, 40.9%, 37.9%, 23.9% [NS]). Among injectors with a stable partner, 81.3% in Galicia, 75.9% in Madrid, 86.1% in Seville and 79.7% in Valencia reported that his/her serological status was negative for HIV or was unknown (p < 0.001). CONCLUSIONS: ISIP is more prevalent than injection with syringes already used by others. For a substantial percentage of injectors, ISIP is the only risk practice. ISIP and the low use of condoms, particularly with steady partners, could be a contributory factor to the spread of HIV, hepatitis C virus, and hepatitis B virus infection.