The longevity of metal-on-polyethylene (MoP) joint replacements, in which a polished CoCr component articulates with a polyethylene liner, may be restricted by mechanical instability or inflammation ...resulting from osteolysis caused by polyethylene wear debris. Recently, laser surface texturing (LST) has emerged as an effective method to improve the tribological performance of lubricated friction pairs. The present work reports a microstructural and tribological study of surface microtextured CoCr alloy discs, modified by the LST method using a pulsed Nd:YAG laser, tested against Ultra High Molecular Weight Polyethylene (UHMWPE) cylindrical pins. Four different texturing patterns varying laser parameters such as peak power, pulse width, repetition rate and travel speed were investigated. An untextured set of CoCr alloy discs was used as reference. The microstructure and mechanical properties of the microtextured CoCr alloy discs were investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, atomic force microscopy, profilometry and nanoindentation test. The coefficient of friction and wear of the UHMWPE pins were determined by means of a pin-on-disc tribometer under lubricated sliding conditions. The microstructural analysis on the laser microtextured CoCr alloy revealed a grain refinement of secondary phases with absence of typical carbides resulting in an increased nanohardness. In addition, all texturing patterns on the CoCr alloy discs promoted a reduction on the coefficient of friction, compared against untextured CoCr alloy discs. Furthermore, it was found that UHMWPE wear was reduced when articulating against dimple textured CoCr alloy discs.
•Laser surface texturing LST allows generating microtextures patterns on CoCr alloy.•Laser microtextured CoCr alloy presented a grain refinement resulting in a hardness increased.•Boundary mixed and hydrodynamic lubrication was superior on textured samples.•Dimple patterns improved the effect on hydrodynamic lubrication and wear.
We hypothesized that mandibular cortical width (MCW) is smaller in children with osteogenesis imperfecta (OI) than in healthy children and that pamidronate can improve the cortical mandibular ...thickness. The aim of this study was to assess changes in the MCW on dental panoramic radiographs (DPRs) of children with normal bone mineral density (BMD) and with OI. We also compared the MCW of children with different types of OI regarding the number of pamidronate cycles and age at the beginning of treatment. MCW measurements were retrospectively obtained from 197 DPRs of 66 children with OI types I, III, and IV who were in treatment with a comparable dosage of cyclical intravenous pamidronate between 2007 and 2013. The control group had 92 DPRs from normal BMD children. Factorial analysis of variance was used to compare MCW measurements among different age groups and between sexes and also to compare MCW measurements of children with different types of OI among different pamidronate cycles and age at the beginning of treatment. No significant differences in results were found between male and female subjects in both OI and healthy children, so they were evaluated altogether (P > 0.05). There was an increase of MCW values related to aging in all normal BMD and OI children but on a smaller scale in children with OI types I and III. Children with OI presented lower mean MCW values than did children with normal BMD at the beginning of treatment (P < 0.05). A linear model estimated the number of pamidronate cycles necessary to achieve mean MCW values equivalent to those of healthy children. The thinning of the mandibular cortex depended on the number of pamidronate cycles, the type of OI, and the age at the beginning of treatment. DPRs could thus provide a way to identify cyclic pamidronate treatment outcomes in patients with OI.
Adult acute myeloid leukemia (AML) is a highly heterogeneous stem cell malignancy characterized by the clonal expansion of immature myeloid precursors. AML may emerge de novo, following other ...hematopoietic malignancies or after cytotoxic therapy for other disorders. Here, we investigated the clonal vs reactive nature of residual maturing bone marrow cells in 59 newly diagnosed adult AML and mixed phenotype acute leukemia (MPAL) patients as assessed by interphase fluorescence in situ hybridization analysis of AML and myelodysplastic syndrome-associated cytogenetic alterations and/or the pattern of chromosome X inactivation, in females. In addition, we investigated the potential association between the degree of molecular/genetic involvement of hematopoiesis and coexistence of altered immunophenotypes by flow cytometry. Our results indicate that residual maturing neutrophils, monocytes and nucleated red cell precursors from the great majority of newly diagnosed AML and MPAL cases show a clonal pattern of involvement of residual maturing hematopoietic cells, in association with a greater number of altered immunophenotypes. These findings are consistent with the replacement of normal/reactive hematopoiesis by clonal myelopoiesis and/or erythropoiesis in most newly diagnosed AML and MPAL cases, supporting the notion that in most adults presenting with de novo AML, accumulation of blast cells could occur over a pre-existing clonal hematopoiesis.
Taro starch spherical aggregates have good potential as wall material for microencapsulation of hydrophobic compounds. This study considered these spherical aggregates for protection of almond oil ...against oxidative stress. Encapsulation efficiency, microcapsules morphology and physical and chemical stability of the microcapsules were determined. The total encapsulation efficiency (TE) was 56.0 ± 0.6%, while the effective encapsulation efficiency was 37.5 ± 0.5%. The size of the microcapsules was in the range 1.6–31.1 μm, with porous structure that allows the flow of solvents through the intraparticle cavities. It was found that the almond oil was located mostly in the internal cavities of the spherical aggregates. Spray drying induced an increase in the peroxide value of the almond oil at the time of microencapsulation, which in turn enhanced the chemical stability. The maximum physical stability of the microcapsules was found around 8.2 g∙100 g−1 of moisture content for temperatures in the range 25–45 °C of storage. Overall, the results showed that the spherical aggregates provide protection against oxidation reactions to microencapsulated almond oil.
•Taro starch spherical aggregates have potential for microencapsulation of oil.•Total encapsulation efficiency of the almond oil was 56%.•Almond oil was located mostly in the internal cavities of the spherical aggregates.•Microcapsules size was in the range 1.6–31.1 μm.
Analysis of clinical isolates of Vibrio parahaemolyticus from outbreaks in Chile in the cities of Puerto Montt in 2004 and Antofagasta in 1998 indicated that 23 of 24 isolates from Puerto Montt and ...19 of 20 from Antofagasta belonged to the pandemic clonal complex that emerged in Southeast Asia in 1996.
Highlights • Vaccines for preventing serogroup AWX meningococcal disease needed in Africa. • An outer membrane vesicle (OMV) vaccine from serogroup AWX meningocci developed. • AWX-OMV vaccine shown ...to induce bactericidal and opsonic antibodies in mice. • Combination of AW-OMV with X polysaccharide also induced bactericidal antibodies. • Vaccine based on AWX-OMV or AW-OMV + X polysaccharide may prevent majority of cases.
The purpose of this retrospective study was to determine the prevalence of hypodontia and associated dental anomalies in patients undergoing orthodontic treatment in Brasília, Brazil, over a 2 year ...period (1998–2000). The records of 1049 orthodontic patients between 10 and 15.7 years of age (507 males and 542 females) from 16 orthodontic clinics were analysed. Descriptive statistics were performed for the study variables. A chi-square test was used to determine the difference in the prevalence of hypodontia between genders. The prevalence of hypodontia was 6.3 per cent (39.4 per cent males and 60.6 per cent females) with no statistically significant difference between the genders. One case of oligodontia was observed. The maxillary lateral incisor was the most frequently missing tooth, followed by the mandibular second premolar. All cases of hypodontia, except one, were associated with at least one other dental anomaly. These associated dental anomalies were retained primary teeth (30.3 per cent), ectopic canine eruption (25.8 per cent), taurodontism (21.2 per cent), and peg-shaped maxillary lateral incisors (16.7 per cent).
Examining whether contextual factors influence the birth outcomes of Mexican-origin infants in the US may contribute to assessing rival explanations for the so-called Mexican health paradox. We ...examined whether birthweight among infants born to Mexican-origin women in the US was associated with Mexican residential enclaves and exposure to neighborhood poverty, and whether these associations were modified by nativity (i.e. mother's place of birth). We calculated metropolitan indices of neighborhood exposure to Mexican-origin population and poverty for the Mexican-origin population, and merged with individual-level, year 2000 natality data (
n
=
490,332). We distinguished between neighborhood exposure to US-born Mexican-origin population (i.e. ethnic enclaves) and neighborhood exposure to foreign-born (i.e. Mexico-born) Mexican-origin population (i.e. immigrant enclaves). We used 2-level hierarchical linear regression models adjusting for individual, metropolitan, and regional covariates and stratified by nativity. We found that living in metropolitan areas with high residential segregation of US-born Mexican-origin residents (i.e. high prevalence of ethnic enclaves) was associated with lower birthweight for infants of US-born Mexican-origin mothers before and after covariate adjustment. When simultaneously adjusting for exposure to ethnic and immigrant enclaves, the latter became positively associated with birthweight and the negative effect of the former increased, among US-born mothers. We found no contextual birthweight associations for mothers born in Mexico in adjusted models. Our findings highlight a differential effect of context by nativity, and the potential health effects of ethnic enclaves, which are possibly a marker of downward assimilation, among US-born Mexican-origin women.
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