3,056 research outputs found

    INJECTABLE HYBRID SYSTEM FOR STRONTIUM LOCAL DELIVERY TO PROMOTE BONE REGENERATION

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    In bone tissue regeneration strategies, injectable bone substitutes are very attractive since they can be applied with minimally invasive surgical procedures and can perfectly fill irregular defects created in cases of trauma, infection or tumor resection. These materials must combine adequate mechanical properties with the ability to induce new bone formation. Incorporating strontium (Sr) in bone substitute biomaterials may be a strategy to achieve high Sr concentrations, not in a systemic but in a local environment, taking advantage of the osteoanabolic and anti-osteoclastic activity of Sr, for the enhancement of new bone formation. In this context, the aim of the present work was to evaluate the response of a Sr-hybrid injectable system for bone regeneration, designed by our group, consisting of hydroxyapatite microspheres doped with Sr and an alginate vehicle crosslinked in situ with Sr, in an in vivo scenario. Two different animal models were used, rat (Wistar) and sheep (Merino Branco) critical sized bone defect. Non Sr-doped similar materials (Ca-hybrid) or empty defects were used as control. Sr-hybrid system led to an increased bone formation in both center and periphery of a rat critical sized defect compared to a non Sr–doped similar system, where new bone formation was restricted to the periphery. Moreover newly formed bone was identified as early as one week after its implantation in a sheep model. After eight weeks, the bone surrounded the microspheres, both in the periphery and in the center of the defect. Most importantly, the hybrid system provided a scaffold for cell migration and tissue ingrowth and offered structural support, as observed in both models. The effective improvement of local bone formation suggests that this might be a promising approach for bone regeneration, especially in osteoporotic conditions

    Adequação do leite produzido no Rio Grande do Sul à instrução normativa 51 do MAPA.

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    bitstream/item/31104/1/COMUNICADO-143.pd

    Physical modification of intermetallic phases in Al-Si-Cu alloys

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    The effect of applying ultrasonic vibration to the melt during cooling on grain structure, type and morphology of intermetallic compounds in AlSi9Cu3(Fe) alloy was studied, as well as their nucleation mechanism. Detailed intermetallics analysis was performed using a combination of SEM/EDS and XRD techniques in order to obtain the most possible reliable information. Results show that without ultrasonic treatment alpha-Al-17(Fe-3.2, Mn-0.8)Si-2, alpha-Al8Fe2Si, beta-Al9Fe2Si2 and Al2Cu are the intermetallic phases present in the as-cast samples. The application of ultrasonic vibration to the melt during cooling proved to be very effective in converting the alpha-intermetallics with Chinese script morphology to polyhedral crystals, suppressing at the same time the formation of the beta-phase. Moreover, the application of this treatment only changes the morphology of alpha-intermetallics since its stoichiometry remains the same (alpha-Al-17(Fe-3.2, Mn-0.8)Si-2). It was also verified that the application of acoustic energy to the melt promotes the change of alpha-Al grains from dendritic to a more globular structure. The ultrasonic treatment is also effective in promoting the fracture of polyhedral crystals of intermetallic phases, reducing their dimensions and causing their homogenous dispersion in the matrix.This research was supported by FEDER/COMPETE funds and by national funds through FCT - Portuguese Foundation for Science and Technology on the aim of the research project PTDC/EME-TME/119658/2010 and the Post-Doctoral Grant SFRH/BPD/76680/2011.info:eu-repo/semantics/publishedVersio

    Orbital Exenteration for Eyelid Skin Carcinoma

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    Exenteration of the orbit is a disfiguring and destructive procedure; it is generally performed for orbital malignancies and often provides a significant reconstructive challenge. Our purpose was to evaluate the clinical indications for orbital exenteration in a tertiary referral center and to assess the reconstructive options employed. A retrospective nonrandomized analysis was performed, selecting all patients undergoing orbital exenteration over a 5-year period, between January 2005 and January 2010. Patient demographics, tumor characteristics, and reconstructive techniques used were evaluated. Twenty patients with a mean age of 76.5 years underwent total orbital exenteration. Basal cell carcinoma was the main operative indication (45%), followed by squamous cell carcinoma (15%). Reconstructive techniques included cover of the raw orbital cavity with a temporal muscular flap in all cases followed with split skin grafting (25%), bilaterally pedicle V-Y advancement flap (10%) and a fasciocutaneous island flap of the retroauricular region (65%). Twenty percent of patients had local complications and all were treated in a satisfactory fashion. Eyelid skin tumors remain an important cause of orbital exenteration. Temporal muscle flap is a reliable and stable reconstructive solution after orbital exenteration and additional aid is supplied with skin grafts or local flaps. This technique ensures a good aesthetic outcome and better situation for later complementary treatments and minimal associated donor site morbidity

    Wearing colored glasses can influence the exercise performance and testosterone concentration

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    Perception of red color is associated with higher testosterone concentration and better human performance. Thus, we evaluated the acute effects of wearing colored-lens glasses on the YoYo intermittent endurance exercise test 2 (YoYoIE2) performance indicators and testosterone concentration. Ten soccer players performed three YoYoIE2 (counterbalanced crossover) wearing colorless (control), blue- or red-lensed glasses (2–4 days of rest in between). YoYoIE2 performance did not differ among the trials (p>0.05), but blood testosterone increased post-exercise in red compared to red baseline (red=14%, effect size=0.75). Analysis showed faster heart rate recovery (p0.05) among the trials. Wearing red-colored lenses during high-intensity intermittent exercise increased testosterone concentration, but do not influence performance

    Comparison of Outcomes in Immediate Implant-Based Breast Reconstruction: Acellular Dermal Matrix versus Inferior Dermal Flap

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    Background Implant-based breast reconstruction has evolved tremendously in the last decades, mainly due to the development of new products and techniques that make the procedure safer and more reliable. The purpose of this study was to compare the outcomes in immediate one-stage breast reconstruction between acellular dermal matrix (ADM) and inferior dermal flap (IDF). Methods We conducted a retrospective comparative study of patients submitted to immediate breast reconstructions with an anatomical implant and ADM or IDF in a single center between 2016 and 2018. Outcomes evaluated included major complications, early complications, reinterventions, readmissions, and reconstruction failure. Simple descriptive statistics and univariate analysis were performed. Results A total of 118 breast reconstructions (85 patients) were included in the analysis. Patients in the IDF group had a higher body mass index (median = 27.0) than patients in the ADM group (median = 24). There were no statistically significant differences among both groups regarding immediate major complication, early complications, readmissions, and reinterventions. Conclusion There are no significant differences in complications between the ADM and IDF approach to immediate implant breast reconstruction. In patients with higher body mass index and large, ptotic breasts, we recommend an immediate implant reconstruction with IDF.info:eu-repo/semantics/publishedVersio

    Validação de seqüência didática sobre o aquecimento global a partir de uma análise das atividades e ações propostas

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    Este trabalho procurou realizar a validação de uma seqüência didática (SD) sobre aquecimento global, proposta a partir de uma situação-problema que foi desenvolvida com alunos do ensino médio de uma escola pública. A SD foi construída articulando os fundamentos da teoria da atividade de Leontiev (1985) e da teoria de assimilação de ações mentais de Galperin (1986). Na análise da seqüência, verificamos que a maior parte das atividades propostas atingiu os seus objetivos e as ações realizadas pelos alunos promoveram aprendizagens significativas no âmbito conceitual e atitudinal. Dessa forma, podemos considerar que a seqüência aplicada alcançou um resultado de aprendizagem satisfatório

    Evaluation of Y2O3 as front layer of ceramic crucibles for vaccum induction melting of tial based alloys

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    During the last decades titanium alloys were found to be valuable engineering materials for many different applications. Formerly used in critical applications like aerospace, aeronautic and military equipment, where the factor cost is not relevant, titanium alloys are finding now new and different markets. However, the development of such new markets will depend on an effective cost reduction of titanium parts, in order to achieve a selling cost suitable with its application in consumer goods. A possible solution to decrease production costs might be the use of traditional casting techniques to produce near net shape functional parts. During the last years, the authors have developed extensive research work on this field, and a new technique both for melting and moulding, using ceramic multi-layered crucibles and investment casting shells was developed. This paper presents some of the results obtained during that research work: Ti-48Al alloy were melted and cooled inside CaO, MgO and Y2O3 stabilized ZrO2 crucibles with inside layer of Y2O3. The chemical composition, hardness and microstructure at the metal-crucible interface, studied by secondary ion mass spectrometry, SEM/EDS and XRS are presented. On a second step, the same alloy was melted on the same crucibles, and poured into graphite moulds, and the crucibles wall was characterized by SEM/EDS and XRS.(undefined
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