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•Binary and ternary Ti alloys were developed.•Ti–Zr alloys exhibited enhanced hardness and electrochemical stability.•Ti–Nb–Zr alloys presented an elastic modulus closer to that of ...bone.•The experimental alloys were not detrimental to albumin adsorption.•The experimental alloys may be considered a suitable candidate for dental implants.
The aim of this study was to develop binary and ternary titanium (Ti) alloys containing zirconium (Zr) and niobium (Nb) and to characterize them in terms of microstructural, mechanical, chemical, electrochemical, and biological properties.
The experimental alloys — (in wt%) Ti–5Zr, Ti–10Zr, Ti–35Nb–5Zr, and Ti–35Nb–10Zr — were fabricated from pure metals. Commercially pure titanium (cpTi) and Ti–6Al–4V were used as controls. Microstructural analysis was performed by means of X-ray diffraction and scanning electron microscopy. Vickers microhardness, elastic modulus, dispersive energy spectroscopy, X-ray excited photoelectron spectroscopy, atomic force microscopy, surface roughness, and surface free energy were evaluated. The electrochemical behavior analysis was conducted in a body fluid solution (pH 7.4). The albumin adsorption was measured by the bicinchoninic acid method. Data were evaluated through one-way ANOVA and the Tukey test (α=0.05).
The alloying elements proved to modify the alloy microstructure and to enhance the mechanical properties, improving the hardness and decreasing the elastic modulus of the binary and ternary alloys, respectively. Ti–Zr alloys displayed greater electrochemical stability relative to that of controls, presenting higher polarization resistance and lower capacitance. The experimental alloys were not detrimental to albumin adsorption.
The experimental alloys are suitable options for dental implant manufacturing, particularly the binary system, which showed a better combination of mechanical and electrochemical properties without the presence of toxic elements.
This study developed an experimental quaternary titanium (Ti) alloy and evaluated its surface properties and electrochemical stability. The viability for a biofunctional surface treatment was also ...tested. Ti-35Nb-7Zr-5Ta (wt%) alloy was developed from pure metals. Commercially pure titanium (cpTi) and Ti-6Al-4V were used as controls. All groups had two surface conditions: untreated (machined surface) and modified by plasma electrolytic oxidation (PEO) (treated surface). The experimental alloy was successfully synthesized and exhibited β microstructure. PEO treatment created a porous surface with increased roughness, surface free energy, hardness and electrochemical stability (p < 0.05). For the machined surfaces, the Ti-Nb-Zr-Ta alloy presented the lowest hardness and elastic modulus (p < 0.05) and displayed greater polarization resistance relative to cpTi. Only PEO-treated cpTi and Ti-Al-V alloys exhibited anatase and rutile as crystalline structures. The β experimental Ti-Nb-Zr-Ta alloy seems to be a good alternative for the manufacture of dental implants, since it presents elastic modulus closer to that of bone, feasibility for surface treatment, electrochemical stability and absence of toxic elements.
•A β experimental Ti-Nb-Zr-Ta alloy with low elastic modulus was developed and functionalized.•The Ti-Nb-Zr-Ta alloy exhibited good electrochemical stability and surface properties.•Plasma electrolytic oxidation (PEO) was a feasible surface treatment for the experimental alloy.•PEO-treated surfaces exhibited remarkable electrochemical stability.
The polysaccharides β-glucans occur as a principal component of the cellular walls. Some microorganisms, such as yeast and mushrooms, and also cereals such as oats and barley, are of economic ...interest because they contain large amounts of β-glucans. These substances stimulate the immune system, modulating humoral and cellular immunity, and thereby have beneficial effect in fighting infections (bacterial, viral, fungal and parasitic). β-Glucans also exhibit hypocholesterolemic and anticoagulant properties. Recently, they have been demonstrated to be anti-cytotoxic, antimutagenic and anti-tumorogenic, making them promising candidate as pharmacological promoters of health.
The chemical composition of biomaterials can drive their biological responses; therefore, this in vitro study aimed to evaluate the proteomic profile of the salivary pellicle formed on titanium (Ti) ...alloys containing niobium (Nb) and zirconium (Zr). The experimental groups consisted of Ti35NbxZr (x = 5 and 10 wt%) alloys, and commercially pure titanium (cpTi); titanium aluminium vanadium (Ti6Al4V) alloys were used as controls. The physical and chemical characteristics of the Ti materials were analysed. The proteomic profile was evaluated by liquid chromatography coupled with tandem mass spectrometry. Bacterial adhesion (2 h) of mixed species (Streptococcus sanguinis and Actinomyces naeslundii) was investigated as colony-forming units (n = 6). This paper reports the finding that salivary pellicle composition can be modulated by the composition of the Ti material. The Ti35NbxZr group showed a significant ability to adsorb proteins from saliva, which can favour interactions with cells and compatibility with the body.
Chemoprevention opens new perspectives in the prevention of cancer and other degenerative diseases. Use of target-organ biological models at the histological and genetic levels can markedly ...facilitate the identification of such potential chemopreventive agents. Colon cancer is one of the highest incidence rates throughout the world and some evidences have indicated carotenoids as possible agents that decrease the risk of colorectal cancer. In the present study, we evaluate the activity of annatto (
Bixa orellana L.), a natural food colorant rich in carotenoid, on the formation of aberrant crypt foci (ACF) induced by dimethylhydrazine (DMH) in rat colon. Further, we investigate, the effect of annatto on DMH-induced DNA damage, by the comet assay. Male Wistar rats were given s.c. injections of DMH (40
mg/kg body wt.) twice a week for 2 weeks to induce ACF. They also received experimental diets containing annatto at 20, 200 or 1000
ppm for five 5 weeks before (pre-treatment), or 10 weeks after (post-treatment) DMH treatment. In both protocols the rats were sacrificed on week 15th. For the comet assay, the animals were fed with the same experimental diets for 2 weeks. Four hours before the sacrifice, the animals received an s.c. injection of DMH (40
mg/kg body wt.). Under such conditions, dietary administration of 1000
ppm annatto neither induce DNA damage in blood and colon cells nor aberrant crypt foci in rat distal colon. Conversely, annatto was successful in inhibiting the number of crypts/colon (animal), but not in the incidence of DMH-induced ACF, mainly when administered after DMH. However, no antigenotoxic effect was observed in colon cells. These findings suggest possible chemopreventive effects of annatto through their modulation of the cryptal cell proliferation but not at the initiation stage of colon carcinogenesis.
•Suspicion of strongyloidiasis in immunodepressed individuals in endemic areas is essential.•Detection of S. stercoralis in patients with diabetes has clinical and diagnostic implications.•IgG and ...IgG4 are usefull for strongyloidiasis detection in patients with diabetes in endemic areas.
We report the detection of IgG, IgG1, IgG4 and IgE anti-Strongyloides stercoralis as complementary tool for screening in patients with diabetes in hyperendemic areas for strongyloidiasis. A panel of 119 serum samples were analyzed: 76 from patients with DM2 and 43 patients with other endocrine diseases and a positive correlation for total IgG levels with IgG4 (rs = 0.559; P = 0.024; n = 16) and IgG and IgE (rs = 0.585; P < 0.0001; n = 76) was found in the diabetes group.
Abstract Background Atherosclerotic coronary artery disease (CAD) is a multifactorial process that appears to be caused by the interaction of environmental risk factors with multiple predisposing ...genes. It is nowadays accepted that increased levels of DNA damage induced by xenobiotics play an important role in the early phases of atherogenesis. Therefore, in this study, we focus on determining whether genetic variations in xenobiotic-metabolizing glutathione- S -transferase theta 1 ( GSTT1 ), glutathione- S -transferase mu 1 ( GSTM1 ), cytochrome P450 IIEI (CYP2E1) and DNA repair X-ray cross-complementing group 1 ( XRCC1 ) genes might be associated with increased risk for CAD. Methods A case-control study was conducted with 400 individuals who underwent subjected to coronary angiography. A total of 299 were patients diagnosed with effective coronary atherosclerosis (case group; >20% obstructive lesion), and 101 (control group) were individuals diagnosed as negative for CAD (<20% obstructive lesions). The polymorphism identifications for GSTM1 and GSTT1 , and for CYP2E1 and XRCC1 genes were performed by polymerase chain reaction (PCR) amplification and by PCR-RFLP, respectively. Results and conclusions The XRCC1 homozygous wild-type genotype Arg/Arg for codon 399 was statistically less pronounced in the case subjects (21.4%) than in controls (38.5%); individuals with the variant XRCC1 genotype had a 2.3-fold increased risk for coronary atherosclerosis than individuals with the wild-type genotype (OR=2.3, 95% CI=1.13–4.69). Conversely, no association between GSTM1 , GSTT1 , and CYP2E1 gene polymorphisms and coronary atherosclerosis was detected. The results provide evidence of the role of DNA damage and repair in cardiovascular disease.
This study was undertaken to understand how Lentinula edodes modulates in vivo mutagenesis induced by alkylating agents in bone marrow and peripheral blood as described in our previous article. Male ...Swiss mice were pretreated for 15 consecutive days with aqueous extracts prepared from L. edodes, after which, the number of circulating blood cells, normal erythroid bone marrow cell cycling, and phagocytosis of micronucleated reticulocyte (MNRET) and activation of spleen macrophages were assessed. The results indicate that the antimutagenicity seen in bone marrow and peripheral blood is exerted by distinct compounds with different actions. The antimutagenic effect in bone marrow is exerted by compounds subject to degradation at deep-freeze storage temperature of −20°C. On the other hand, compounds responsible for antimutagenicity in peripheral blood are not subject to degradation at −20°C. The results also indicate that the antimutagenic action in peripheral blood leading to the reduction of circulating MNRET occurs in the spleen primarily through a phagocytic activity due to higher macrophage numbers and probably not due to the enhanced activation state of individual cells.
Temporary wetlands are short-term alternative ecosystems formed by flooding for irrigation of areas used for rice farming. The goal of this study is to describe the development cycle of rice fields ...as temporary wetlands in southern Brazil, evaluating how this process affect the gas production (CH4 and CO2) in soil with difference % carbon and organic matter content. Two areas adjacent to Lake Mangueira in southern Brazil were used during a rice-farming cycle. One area had soil containing 1.1% carbon and 2.4% organic matter, and the second area had soil with 2.4% carbon and 4.4% organic matter. The mean rates of gas production were 0.04 ± 0.02 mg CH4 m(-2) d(-1) and 1.18 ± 0.30 mg CO2 m(-2) d(-1) in the soil area with the lower carbon content, and 0.02 ± 0.03 mg CH4 m(-2) d(-1) and 1.38 ± 0.41 mg CO2 m(-2) d(-1) in the soil area with higher carbon content. Our results showed that mean rates of CO2 production were higher than those of CH4 in both areas. No statistically significant difference was observed for production of CH4 considering different periods and sites. For carbon dioxide (CO2), however, a Two-Way ANOVA showed statistically significant difference (p = 0.05) considering sampling time, but no difference between areas. The results obtained suggest that the carbon and organic matter contents in the soil of irrigated rice cultivation areas may have been used in different ways by soil microorganisms, leading to variations in CH4 and CO2 production.
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