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Titanium and its alloys have been widely used in many engineering areas due to their properties. Despite having a high implant-tissue osseointegration time, Ti6Al4V has been extensively used in prosthesis and articular implants. To promote a faster bone ingrowth and consequently reduce the implant fixation time, the addition of a bioactive phase to form a biocomposite seems to be an excellent solution. Because of their bioactivity and similarity in composition with the human bone, HAp and ß-TCP are two of the most widely used calcium phosphates in biomedical applications. To guarantee a strong adhesion of the previous bioactive materials in the implants surface, samples of Ti6Al4V, Ti6Al4V+HAp (10 vol %) and Ti6Al4V+ß-TCP (10 vol %) TCP were processed by the hot pressing technique. Tribological tests against Al2 O3, lubricated in PBS at 37°C were carried out on a ball-on-flat reciprocating sliding geometry. Loads in the range of 3 N to 30 N were applied and their effect on the friction behavior and wear resistance of the tested materials was evaluated. Values of the coefficient of friction as well as the wear rate tend to increase with the addition of a bioactive phase to the Ti alloy. Micrographs of the worn surfaces showed that abrasion and plastic deformation are the prevailing wear mechanisms in the studied tribosystems. For biocomposites, particularly in the case of Ti6Al4V+HAp, pull-out of bioactive particle clusters has a determinant role on the tribological response, increasing both the friction coefficient and the specific wear rate. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1010-1016, 2018.

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This work presents a novel texture design for implants surface functionalization, through the creation of line-shaped textures on Ti6Al4V surfaces and subsequent sintering of hydroxyapatite (HAp) powder into the designated locations. HAp-rich locations were designed to avoid HAp detachment during insertion, thus guaranteeing an effective osseointegration. This process starts by creating textured lines using a Nd:YAG laser, filling these lines with HAp powder and sintering HAp using a CO2 laser. The adhesion of HAp is known to be influenced by HAp sintering parameters, especially laser power and scanning speed and also by the textured lines manufacturing. Different laser parameters combinations were used to assess the sintering and adhesion of HAp to the textured lines. HAp adhesion was assessed by performing high energy ultrasonic cavitation tests and sliding tests mimicking an implant insertion, with Ti6Al4V/HAp specimens sliding against animal bone. The HAp content retained after these tests was measured and results showed that an excellent HAp sintering and adhesion was achieved when using a scan speed of 1 mm/s and laser power between 9 and 9.6 W. It is important to emphasize that results indicated that the HAp bioactivity was maintained when using these conditions, validating this functionalization process for the production of hip prosthesis with improved bioactivity. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1534-1545, 2018.

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Secondary metabolites produced by Actinobacteria of tropical soils represent a largely understudied source of novel molecules with relevant application in medicine, pharmaceutical and food industries, agriculture, and environmental bioremediation. The present study aimed to characterize sixty-nine Actinobacteria isolated from compost and tropical soils using morphological, biochemical, and molecular methods. All the isolates showed high variation for morphological traits considering the color of pigments of the aerial and vegetative mycelium and spore chain morphology. The enzymatic activity of amylase, cellulase, and lipase was highly variable. The amylase activity was detected in 53 (76.81%) isolates. Eighteen isolates showed enzymatic index (EI) > 4.0, and the isolates ACJ 45 (Streptomyces curacoi) and ACSL 6 (S. hygroscopicus) showed the highest EI values (6.44 and 6.42, respectively). The cellulase activity varied significantly (P ≤ 0.05) among the isolates. Twenty-nine isolates (42.02%) showed high cellulase activity, and the isolates ACJ 48 (S. chiangmaiensis) and ACJ 53 (S. cyslabdanicus) showed the highest EI values (6.56 for both isolates). The lipase activity varied statistically (P ≤ 0.05) with fourteen isolates (20.29%) considered good lipase producers (EI > 2.0). The isolate ACSL 6 (S. hygroscopicus) showed the highest EI value of 2.60. Molecular analysis of partial 16S rRNA gene sequencing revealed the existence of 49 species, being 38 species with only one representative member and 11 species represented by one or more strains. All species belonged to three genera, namely Streptomyces (82.61%), Amycolatopsis (7.25%), and Kitasatospora (10.14%). The present results showed the high biotechnological potential of different Actinobacteria from tropical soils.

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The Ti6Al4V alloy constitutes an alternative choice to the most common metal-polymer solutions for total hip arthroplasty (THA) due to good biocompatibility, optimal mechanical properties and high load bearing capacity. However, as Ti6Al4V is not bioactive in its conventional form, hydroxyapatite (HAp) and tricalcium phosphate (TCP) have been widely used as coatings of metal prostheses due to their osteogenic properties and ability to form strong bonds with bone tissue. A promising approach consists in creating a bioactive surface metal matrix composite Ti6Al4V+ß-TCP or Ti6Al4V+HAp, obtained by hot pressing (HP) of powders. In this work, the tribological performance of Ti6Al4V+ß-TCP and Ti6Al4V+HAp composites is studied to evaluate the frictional response and surface damage representative of prosthesis implantation, key factors in bone fixation. Biocomposites with 10vol% ß-TCP and 10vol% Hap, as well as base titanium alloy, were prepared by HP with two surface finishing conditions - polished (Ra=0.3-0.5µm) and sandblasted (Ra=2.1-2.5µm) - for tribological testing against bovine cortical bone tissue. The static friction increases with surface roughness (from 0.20 to 0.60), whereas the kinetic regime follows an inverse trend for the biocomposites. In contrast with current knowledge, this study shows that an implant design solution based on Ti6Al4V+ß-TCP or Ti6Al4V+HAp biocomposites with polished surfaces results in an improved primary stability of implants, when compared to traditional rough surfaces. Moreover, it is also expected that the secondary stability will improve due to the adhesion between bone and HAp/ß-TCP, increasing the overall stability of the implant.

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In the present study, we demonstrated the in vitro activity of endophytic phosphate-solubilizing bacteria (PSB). Fifty-five endophytic PSB that were isolated from sap, leaves, and roots of maize were tested for their ability to solubilize tricalcium phosphate and produce organic acid. Partial sequencing of the 16S rRNA-encoding gene showed that the isolates were from the genus Bacillus and different species of Enterobacteriaceae. The phosphate solubilization index on solid medium and phosphate solubilization in liquid medium varied significantly among the isolates. There was a statistically significant difference (P ≤ 0.05) for both, the values of phosphate-solubilizing activity and pH of the growth medium, among the isolates. Pearson correlation was statistically significant (P ≤ 0.05) between P-solubilization and pH (R = -0.38), and between the gluconic acid production and the lowering of the pH of the liquid medium at 6 (R = 0.28) and 9 days (R = 0.39). Gluconic acid production was prevalent in all the PSB studied, and Bacillus species were most efficient in solubilizing phosphate. This is the first report on the characterization of bacterial endophytes from maize and their use as potential biofertilizers. In addition, this may provide an alternative strategy for improving the phosphorus acquisition efficiency of crop plants in tropical soils.

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The antimicrobial activity of five sanitizing agents employed in clean areas designated for the pharmaceutical manufacturing of sterile products was tested against nine microorganisms, including four microorganisms from the clean area microbiota. The method consisted of challenging 5 mL of each sanitizing agent - 70% isopropyl alcohol, 0.4% LPH®, 1.16% hydrogen peroxide, 4% hydrogen peroxide, 1% Bioper® and 5% phenol - with 0.1mL each of concentrated suspensions (105 ? 106 CFU/mL) of Staphylococcus aureus, Candida albicans, Corynebacterium sp., Micrococcus luteus, Escherichia coli, Aspergillus niger, Bacillus subtilis, Staphylococcus sp. and Bacillus sp. for 10 minutes, followed by serial dilutions and plating. The results demonstrated that the five agents were effective against S. aureus, C. albicans, Corynebacterium sp., and M. luteus. The same was true of E. coli, except that isopropyl alcohol showed low levels of inactivation. With A. niger, isopropyl alcohol, 0.4% LPH® and hydrogen peroxide were more effective and 5% phenol and 1% Bioper® less effective. 1% Bioper® and 4% hydrogen peroxide showed greater inactivation of Staphylococcus sp., Bacillus sp. and B. subtilis than the other agents. Against S. aureus, C. albicans, Corynebacterium sp. and M. luteus, 5% phenol showed similar activity to other agents, while with A. niger, B. subtilis, Staphylococcus sp. and Bacillus sp., it was similar to or less active than the other agents. It was demonstrated that two microorganisms from the clean area microbiota, Staphylococcus sp. and Bacillus sp., were the most difficult to eradicate, requiring more frequent application of hydrogen peroxide and 1% Bioper® than the other strains.

O objetivo deste estudo é avaliar a atividade antimicrobiana de cinco agentes sanitizantes empregados em áreas limpas construídas para a fabricação de produtos farmacêuticos estéreis contra nove microrganismos, incluindo quatro microrganismos oriundos da área limpa. A metodologia constituiu em desafiar 5 mL de cada agente sanitizante, álcool isopropílico 70%, LPH® 0,400%, peróxido de hidrogênio 1,160% e 4%, Bioper® 1% e fenol 5% com 0,1 mL de suspensão concentrada (105 ? 106 UFC/mL) de Staphylococcus aureus, Candida albicans, Corynebacterium sp., Micrococcus luteus, Escherichia coli, Aspergillus niger, Bacillus subtilis, Staphylococcus sp. e Bacillus sp. individualmente por 10 minutos, seguido de diluições seriadas e plaqueamento. Os resultados demonstraram que os cinco agentes sanitizantes foram efetivos contra S. aureus, C. albicans, Corynebacterium sp., e M. luteus. Os mesmos resultados foram observados com E. coli, exceto para o álcool isopropílico, que demonstrou baixos níveis de inativação. Contra A. niger, álcool isopropílico, 0.4% LPH® e peróxido de hidrogênio foram mais efetivos e fenol e Bioper® menos efetivos. Bioper® e peróxido de hidrogênio 4% demonstraram altos níveis de inativação de Staphylococcus sp., Bacillus sp. e B. subtilis quando comparados com outros agentes. Fenol demonstrou atividade antimicrobiana similar aos outros agentes contra S. aureus, C. albicans, Corynebacterium sp. e M. luteus. Contra A. niger, B. subtilis, Staphylococcus sp. e Bacillus sp., a atividade antimicrobiana do fenol foi similar ou inferior a dos outros agentes. Foi demonstrado que os microrganismos isolados da área limpa, Staphylococcus sp. e Bacillus sp., foram os que apresentaram maior dificuldade para inativar, sendo necessária a aplicação de peróxido de hidrogênio e Bioper® , com maior frequência.

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