99 research outputs found

    Effect of implantoplasty on the elastic limit of dental implants of different diameters

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    Background Implantoplasty reduces both implant diameter and the thickness of its walls, subsequently reducing the ability of the implant to resist fracture in response to functional load. In combination with an increase in the crown-implant ratio due to bone loss, this could increase the lever effect, which in presence of high masticatory forces or parafunctional habits, could lead to complications such as fracture of the implant or loosening of the prosthetic screw. Objectives To determine the elastic limits of internal connection, dental implants of different designs and diameters after an implantoplasty. Materials and methods This in vitro study included 315 tapered internal connection titanium dental implants, the threads of which were removed with an industrial milling machine-for standardized implantoplasty (IMP1; n = 105)-or with the conventional approach-manually, using high-speed burs (IMP2; n = 105). The remaining 105 implants were used as controls. The final implant diameters were recorded. The quality of the newly polished surfaces was assessed by scanning electron microscopy. All implants were subjected to a mechanical pressure resistance test. A Tukey''s test for multiple comparisons was used to detect differences in the elastic limit and final implant diameters between the implant groups. Results There were statistically significant differences in the elastic limit between the IMP1, IMP2, and control groups (p < 0.05). Furthermore, the implant diameter was significantly smaller in the IMP1 and IMP2 groups (p < 0.05). Scanning electron microscopy revealed smooth implant surfaces in the IMP1 and IMP2 groups, with some titanium particles visible in the IMP1 group. Conclusions Implantoplasty significantly decreased the elastic limit of internal connection titanium dental implants, especially in those with a smaller diameter (3-3.5 mm)

    Cadeia de valor: histórico e mercado atual.

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    O capítulo apresenta algumas perspectivas para o futuro da cadeia, à luz dos dados e informações existentes na literatura e aqui sintetizados. Espera?se que esse trabalho possa colaborar com outros estudos e pesquisas, somando forças para qualificar essa importante cadeia, tipicamente amazônica e de grande valor para a bioeconomia brasileira.V. 1: Aspectos sociais, econômicos e organizacionais. ODS 2, ODS 3, ODS 8, ODS 11, ODS 12, ODS 13, ODS 17

    Design of a precision compactor for use in guided bone regeneration in the area of oral surgery

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    During the processes of guided bone regeneration in the maxillary bones, which aim to recover or preserve support tissue for the placement of implants on which dental prostheses are retained, the use of various particulate graft biomaterials from different sources (animal or synthetic) is standardized. At present, the pressure of compaction of this material in the recipient bone is manual, dependent on the clinician, although there is some scientific evidence on the effects of different compressive forces on angiogenesis and prognosis of the regeneration of the grafted areas. The aim of the present study is to design, calibrate and verify in vitro a compaction instrument for clinical use, which allows a controlled and precise compaction pressure of the particulate graft biomaterial and standardize the procedure. The designed instrument is a precision compactor of adequate size for proper intra and extraoral clinical manageability and manufactured in a sterilizable material by autoclaving. The range of compression that allows (0 -1, 82 Newton), is within the forces that are commonly applied in surgery and that have been determined by a specific test on 8 oral surgeons. Instrument calibration has been performed by an independent accredited company. The testing of the instrument was carried out by an in vitro test where the biomaterial was compacted at different forces (0, 80 and 1, 82 Newton) and was observed by a computerized micro-tomography that when increasing the compression force, decreased the space between particles provided for the migration and proliferation of new blood vessels and cells. Durante los procedimientos de regeneración ósea guiada en los huesos maxilares, que tienen como objetivo recuperar o preservar tejido de soporte para la colocación de implantes sobre los que se retienen las prótesis dentales, está estandarizado el uso de diversos biomateriales de injerto particulado de diferente procedencia (animal o sintético). En la actualidad la presión de compactación de dicho material en el hueso receptor es manual, clínico dependiente, pese a que existe cierta evidencia científica sobre los efectos de las diferentes fuerzas de compresión en la angiogénesis y pronóstico de la regeneración de las zonas injertadas. El objetivo del presente estudio es el de diseñar, calibrar y comprobar in vitro un instrumento de compactación para uso clínico, que permita una presión de compactación controlada y precisa del biomaterial de injerto particulado y estandarizar el procedimiento. El instrumento diseñado es un compactador de precisión de tamaño adecuado para una correcta manejabilidad clínica intra y extraoral y fabricado en un material esterilizable por autoclavado. El rango de compresión que permite (0 – 1, 82 Newton), está dentro de las fuerzas que se aplican comúnmente en cirugía y que se han determinado mediante una prueba específica sobre 8 cirujanos orales. La calibración del instrumento se ha realizado por una empresa acreditada independiente. La comprobación del instrumento se ha realizado mediante un ensayo in vitro donde se compactó el biomaterial a diferentes fuerzas (0, 80 y 1, 82 Newton) y se observó mediante micro-tomografía computerizada que al aumentar la fuerza de compresión disminuía el espacio entre partículas provisto para la migración y proliferación de los nuevos vasos sanguíneos y células

    Aniline incorporated silica nanobubbles

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    We report the synthesis of stearate functionalized nanobubbles of SiO2 with a few aniline molecules inside, represented as C6H5NH2@SiO2@stearate, exhibiting fluorescence with red-shifted emission. Stearic acid functionalization allows the materials to be handled just as free molecules, for dissolution, precipitation, storage etc. The methodology adopted involves adsorption of aniline on the surface of gold nanoparticles with subsequent growth of a silica shell through monolayers, followed by the selective removal of the metal core either using sodium cyanide or by a new reaction involving halocarbons. The material is stable and can be stored for extended periods without loss of fluorescence. Spectroscopic and voltammetric properties of the system were studied in order to understand the interaction of aniline with the shell as well as the monolayer, whilst transmission electron microscopy has been used to study the silica shell

    A novel modelling toolkit for unpacking the Water-Energy-Food-Environment (WEFE) nexus of agricultural development

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    Increasing food demand has led to significant agricultural expansion globally with negative impacts on resources and the environment, a perfect manifestation of the Water-Energy-Food-Environment nexus. Whilst many tools have been developed to understand the complexity of the Water-Energy-Food-Environment nexus most have failed to explicitly consider biophysical and socio-economic aspects simultaneously. A novel Water-Energy-Food-Environment modelling toolkit is developed that integrates both these components by combining different modelling approaches including irrigation simulation, economic modelling and life cycle environmental assessment. The toolkit is demonstrated using two major agro-export crops (asparagus and table grapes) in the Ica Valley, Peru, a severely water-stressed region. The toolkit was able to provide novel insights into the implications of different farming practices on resource efficiency at the field level in relation to water and energy, under contrasting future scenarios reflecting socio-economic outcomes at the local to regional levels (e.g., food prices, employment, and income) as well as environmental impacts at local to global scales. This information enables different stakeholders to better understand the interlinkages and inter-dependences between the Water-Energy-Food-Environment nexus elements and the complex impacts of agricultural expansion beyond the immediate sector and its geographical extent, helping decision makers design more coordinated agricultural policies and support sustainable agricultural transformation.Natural Environment Research Council (NERC): NE/R015759/1. Chilean National Agency for Research and Development (ANID/CONICYT) - FONDE

    The role of retinal fluid location in atrophy and fibrosis evolution of patients with neovascular age-related macular degeneration long-term treated in real world

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    Purpose: To assess the effect of clinical factors on the development and progression of atrophy and fibrosis in patients with neovascular age-related macular degeneration (nAMD) receiving long-term treatment in the real world. Methods: An ambispective 36-month multicentre study, involving 359 nAMD patients from 17 Spanish hospitals treated according to the Spanish Vitreoretinal Society guidelines, was designed. The influence of demographic and clinical factors, including the presence and location of retinal fluid, on best-corrected visual acuity (BCVA) and progression to atrophy and/or fibrosis were analysed. Results: After 36 months of follow-up and an average of 13.8 anti-VEGF intravitreal injections, the average BCVA gain was +1.5 letters, and atrophy and/or fibrosis were present in 54.8% of nAMD patients (OR = 8.54, 95% CI = 5.85-12.47, compared to baseline). Atrophy was associated with basal intraretinal fluid (IRF) (OR = 1.87, 95% CI = 1.09-3.20), whereas basal subretinal fluid (SRF) was associated with a lower rate of atrophy (OR = 0.40, 95% CI = 0.23-0.71) and its progression (OR = 0.44, 95% CI = 0.26-0.75), leading to a slow progression rate (OR = 0.34, 95% CI = 0.14-0.83). Fibrosis development and progression were related to IRF at any visit (p < 0.001). In contrast, 36-month SRF was related to a lower rate of fibrosis (OR = 0.49, 95% CI = 0.29-0.81) and its progression (OR = 0.50, 95% CI = 0.31-0.81). Conclusion: Atrophy and/or fibrosis were present in 1 of 2 nAMD patients treated for 3 years. Both, especially fibrosis, lead to vision loss. Subretinal fluid (SRF) was associated with good visual outcomes and lower rates of atrophy and fibrosis, whereas IRF yields worse visual results and a higher risk of atrophy and especially fibrosis in routine clinical practice

    Micronutrient Deficits Are Still Public Health Issues among Women and Young Children in Vietnam

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    Background: The 2000 Vietnamese National Nutrition Survey showed that the population’s dietary intake had improved since 1987. However, inequalities were found in food consumption between socioeconomic groups. As no national data exist on the prevalence of micronutrient deficiencies, a survey was conducted in 2010 to assess the micronutrient status of randomly selected 1526 women of reproductive age and 586 children aged 6–75 mo. Principal Findings: In women, according to international thresholds, prevalence of zinc deficiency (ZnD, 67.262.6%) and vitamin B12 deficiency (11.761.7%) represented public health problems, whereas prevalence of anemia (11.661.0%) and iron deficiency (ID, 13.761.1%) were considered low, and folate (,3%) and vitamin A (VAD,,2%) deficiencies were considered negligible. However, many women had marginal folate (25.1%) and vitamin A status (13.6%). Moreover, overweight (BMI$23 kg/m 2 for Asian population) or underweight occurred in 20 % of women respectively highlighting the double burden of malnutrition. In children, a similar pattern was observed for ZnD (51.963.5%), anemia (9.161.4%) and ID (12.961.5%) whereas prevalence of marginal vitamin A status was also high (47.362.2%). There was a significant effect of age on anemia and ID prevalence, with the youngest age group (6–17 mo) having the highest risk for anemia, ID, ZnD and marginal vitamin A status as compared to other groups. Moreover, the poorest groups of population had a higher risk for zinc, anemia and ID

    Discordant identification of pediatric severe sepsis by research and clinical definitions in the SPROUT international point prevalence study

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    Introduction: Consensus criteria for pediatric severe sepsis have standardized enrollment for research studies. However, the extent to which critically ill children identified by consensus criteria reflect physician diagnosis of severe sepsis, which underlies external validity for pediatric sepsis research, is not known. We sought to determine the agreement between physician diagnosis and consensus criteria to identify pediatric patients with severe sepsis across a network of international pediatric intensive care units (PICUs). Methods: We conducted a point prevalence study involving 128 PICUs in 26 countries across 6 continents. Over the course of 5 study days, 6925 PICU patients &lt;18 years of age were screened, and 706 with severe sepsis defined either by physician diagnosis or on the basis of 2005 International Pediatric Sepsis Consensus Conference consensus criteria were enrolled. The primary endpoint was agreement of pediatric severe sepsis between physician diagnosis and consensus criteria as measured using Cohen's ?. Secondary endpoints included characteristics and clinical outcomes for patients identified using physician diagnosis versus consensus criteria. Results: Of the 706 patients, 301 (42.6 %) met both definitions. The inter-rater agreement (? ± SE) between physician diagnosis and consensus criteria was 0.57 ± 0.02. Of the 438 patients with a physician's diagnosis of severe sepsis, only 69 % (301 of 438) would have been eligible to participate in a clinical trial of pediatric severe sepsis that enrolled patients based on consensus criteria. Patients with physician-diagnosed severe sepsis who did not meet consensus criteria were younger and had lower severity of illness and lower PICU mortality than those meeting consensus criteria or both definitions. After controlling for age, severity of illness, number of comorbid conditions, and treatment in developed versus resource-limited regions, patients identified with severe sepsis by physician diagnosis alone or by consensus criteria alone did not have PICU mortality significantly different from that of patients identified by both physician diagnosis and consensus criteria. Conclusions: Physician diagnosis of pediatric severe sepsis achieved only moderate agreement with consensus criteria, with physicians diagnosing severe sepsis more broadly. Consequently, the results of a research study based on consensus criteria may have limited generalizability to nearly one-third of PICU patients diagnosed with severe sepsis
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