615 research outputs found

    Blue light absorption enhancement based on vertically channelling modes in nano-holes arrays

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    We investigate the specific optical regime occurring at short wavelengths, in the high absorption regime, in silicon thin-films patterned by periodically arranged nano-holes. Near-field scanning optical microscopy indicates that the incoming light is coupled to vertically channelling modes. Optical modelling and simulations show that the light, travelling inside the low-index regions, is absorbed at the direct vicinity of the nano-holes sidewalls. This channelling regime should be taken into account for light management in optoelectronic devices

    Differential cartilaginous tissue formation by human synovial membrane, fat pad, meniscus cells and articular chondrocytes

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    Objective: To identify an appropriate cell source for the generation of meniscus substitutes, among those which would be available by arthroscopy of injured knee joints. Methods: Human inner meniscus cells, fat pad cells (FPC), synovial membrane cells (SMC) and articular chondrocytes (AC) were expanded with or without specific growth factors (Transforming growth factor-betal, Fibroblast growth factor-2 and Plate let-derived growth factor bb, TFP) and then induced to form three-dimensional cartilaginous tissues in pellet cultures, or using a hyaluronan-based scaffold (Hyaff(R)-11), in culture or in nude mice. Human native menisci were assessed as reference. Results: Cell expansion with TFP enhanced glycosaminoglycan (GAG) deposition by all cell types (up to 4.1-fold) and messenger RNA expression of collagen type II by FPC and SMC (up to 472-fold) following pellet culture. In all models, tissues generated by AC contained the highest fractions of GAG (up to 1.9 were positively stained for collagen type II (specific of the inner avascular region of meniscus), type IV (mainly present in the outer vascularized region of meniscus) and types I, III and VI (common to both meniscus regions). Instead, inner meniscus, FPC and SMC developed tissues containing negligible GAG and no detectable collagen type II protein. Tissues generated by AC remained biochemically and phenotypically stable upon ectopic implantation. Conclusions: Under our experimental conditions, only AC generated tissues containing relevant amounts of GAG and with cell phenotypes compatible with those of the inner and outer meniscus regions. Instead, the other investigated cell sources formed tissues resembling only the outer region of meniscus. It remains to be determined whether grafts based on AC will have the ability to reach the complex structural and functional organization typical of meniscus tissue. (C) 2006 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights rese

    The application of stem cells from different tissues to cartilage repair

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    The degeneration of articular cartilage represents an ongoing challenge at the clinical and basic level. Tissue engineering and regenerative medicine using stem/progenitor cells have emerged as valid alternatives to classical reparative techniques. This review offers a brief introduction and overview of the field, highlighting a number of tissue sources for stem/progenitor cell populations. Emphasis is given to recent developments in both clinical and basic sciences. The relative strengths and weaknesses of each tissue type are discussed

    Determinantes de transferencia espermática en Holocnemus pluchei (Araneae: Pholcidae): Importancia de variables corporales y comportamentales desde la selección sexual

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    Fil: Cargnelutti, Franco I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I. Laboratorio de Biología Reproductiva y Evolución; Argentina.Fil: Bolatti, Fedra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I. Laboratorio de Biología Reproductiva y Evolución; Argentina.Fil: Calbacho-Rosa, Lucia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I. Laboratorio de Biología Reproductiva y Evolución; Argentina.Fil: Calbacho-Rosa, Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Diversidad y Ecología Animal; Argentina.Fil: Peretti, Alfredo V. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I. Laboratorio de Biología Reproductiva y Evolución; Argentina.Fil: Peretti, Alfredo V. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Diversidad y Ecología Animal; Argentina.Diversos estudios han demostrado que la duración de la cópula en arácnidos es más larga de lo necesario para transferir el esperma requerido para la fertilización. Esto podría implicar la existencia de procesos, tales como elección femenina críptica y/o competencia espermática. Los machos de la araña Holocnemus pluchei realizan movimientos con ambos pedipalpos de manera simultánea, asociados a la transferencia de esperma, cuando copulan con hembras vírgenes. Dichos movimientos no son constantes y se extienden en la primera mitad de la cópula. Nuestros objetivos fueron: 1- Investigar si en esta especie la cantidad de esperma transferido a las hembras está relacionada con la duración total de la cópula, 2- Determinar si el tamaño y el peso de machos y hembras influye sobre la cantidad de esperma transferido, y 3- Evaluar si las frecuencias y duraciones de los movimientos simultáneos que los machos realizan se asocian con la cantidad de esperma que éstos transfieren. Se realizaron dos tratamientos, uno de cópulas completas (n=18) y otro de cópulas incompletas (n=10), las cuales se interrumpieron al finalizar los movimientos pedipalpares. Se comparó el número de espermatozoides almacenados en el útero de las hembras y el remanente en los bulbos espermáticos de los machos con respecto a la duración de las cópulas, tamaño y peso de los individuos y a variables comportamentales (frecuencia y duración de movimientos pedipalpares) en el tratamiento de cópulas completas como incompletas. Nuestros resultados en curso muestran en ambos tratamientos que ni la duración de las cópulas (r=0,099, p=0,3389; r=-0,1698, p=0,6391), ni el tamaño (r=0,3437,p=0,1271; r=0,0767, p=0,8331) y peso de las hembras (r=0,4088, p=0,0921; r=-0,3437, p=0,332) ni de machos(r=-0,0771, p=0,7331; r=-0,2846, p=0,4255; r=-0,0026, p=0,9915; r=-0,1152, p=0,7514) estarían relacionados con la cantidad de esperma transferido. Sin embargo, resultados preliminares indican que la frecuencia y duración de los movimientos pedipalpares podrían asociarse con la cantidad de esperma transferido. Se discuten los resultados obtenidos, próximos a completar, desde perspectivas de selección sexual.http://cuz.szu.org.uy/libro_resumenes/Libro%20resumenes%20IIICUZ.pdfFil: Cargnelutti, Franco I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I. Laboratorio de Biología Reproductiva y Evolución; Argentina.Fil: Bolatti, Fedra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I. Laboratorio de Biología Reproductiva y Evolución; Argentina.Fil: Calbacho-Rosa, Lucia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I. Laboratorio de Biología Reproductiva y Evolución; Argentina.Fil: Calbacho-Rosa, Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Diversidad y Ecología Animal; Argentina.Fil: Peretti, Alfredo V. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I. Laboratorio de Biología Reproductiva y Evolución; Argentina.Fil: Peretti, Alfredo V. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Diversidad y Ecología Animal; Argentina.Zoología, Ornitología, Entomología, Etologí

    Discrimination against HIV-Infected People and the Spread of HIV: Some Evidence from France

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    BACKGROUND: Many people living with HIV/AIDS (PLWHA) suffer from stigma and discrimination. There is an ongoing debate, however, about whether stigma, fear and discrimination actually fuel the persisting spread of HIV, or slow it down by reducing contacts between the whole population and high-risk minorities. To contribute to this debate, we analysed the relationship between perceived discrimination and unsafe sex in a large sample of French PLWHAs. METHODOLOGY/PRINCIPAL FINDINGS: In 2003, we conducted a national cross-sectional survey among a random sample of HIV-infected patients. The analysis was restricted to sexually active respondents (N = 2,136). Unsafe sex was defined as sexual intercourse without a condom with a seronegative/unknown serostatus partner during the prior 12 months. Separate analyses were performed for each transmission group (injecting drug use (IDU), homosexual contact, heterosexual contact). Overall, 24% of respondents reported experiences of discrimination in their close social environment (relatives, friends and colleagues) and 18% reported unsafe sex during the previous 12 months. Both prevalences were higher in the IDU group (32% for perceived discrimination, 23% for unsafe sex). In multivariate analyses, experience of discrimination in the close social environment was associated with an increase in unsafe sex for both PLWHAs infected through IDU and heterosexual contact (OR = 1.65 and 1.80 respectively). CONCLUSIONS: Our study clearly confirms a relationship between discrimination and unsafe sex among PLWHAs infected through either IDU or heterosexual contact. This relationship was especially strong in the heterosexual group that has become the main vector of HIV transmission in France, and who is the more likely of sexual mixing with the general population. These results seriously question the hypothesis that HIV-stigma has no effect or could even reduce the infection spread of HIV

    Hypoxia as a stimulus upon neonatal swinemeniscus cells: highway to phenotypic maturation of meniscal fibro-chondrocytes?

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    Menisci are essential structures in the knee joint where they cover fundamental biomechanical and protective roles (1-3). Menisci are characterized by a peculiar structure that, on one hand, allow them to perform their particular role in the stifle joint, but simultaneously make them a very challenging structure to deal with (2). Immature menisci are featured by numerously elongated cells (fibrocytes-like) in a disorganized matrix composed almost completely of collagen type I and few glycosaminoglycans (GAGs) and have a rich vascularization, on the other hand, mature and functional menisci are characterized by few round-shaped cells,a matrix rich of well ordinated collagen fibres (above all collagen type II) and GAGs, and preserve vascularization only in the outer zone (aka red zone) (1). Great interest, in both human and veterinary medicines, is reserved to the treatment of the injuries of the inner and avascular zone (aka white zone) of the meniscus: until now, there are no perfect solutions for the regeneration or the replacement of this tissue once injured (3). This work is focused on the utilization of an environmental factor like hypoxia in meniscal tissue culture, in order to evaluate if it could be utilized to improve meniscal culture with a view to tissue engineering. Ninety menisci from neonatal pigs (day 0) were harvested and cultured under two different atmospheric conditions (hypoxia with 1% O2 and normoxia) until 14 days. Samples were analysed at 0, 7 and 14 days through histochemical (Safranin-O staining), immunofluorescence and RT-PCR (Sox-9, Hif-1a, Hif-2, Collagen I and II, both methods) and biochemical (DNA, GAGs, DNA/GAGs ratio) techniques to record any possible differences in maturation of meniscal cells. Safranin-O staining allowed to show an increment in matrix deposition and round-shape \u201cfibro-chondrocytic\u201d cells quantity of hypoxia-cultured menisci respect to controls under normal atmospheric conditions. The same maturation shifting was observed by means of immunofluorescence and RT-PCR analysis, characterized by an increment of Sox-9 and collagen II, moving from day zero to 14-days under hypoxic environment, and by biochemical analysis,with an increment of DNA/GAGs ratio typical of mature meniscal tissue (characterized by few cells and much GAGs). This study shows that hypoxia can be considered as a booster to achieve meniscal cells maturation and opens considerably opportunities in the field of meniscus tissue engineering. References 1. Dai Z, et al. J Orthop Res 2013 ;31:1514-9, 2. Fox AJS, et al. Clin Anat 2015 ;28:269-87 3. Sosio C, et al. Tissue Eng Part A 2015 ;21:3-4

    Salvage carbon dioxide transoral laser microsurgery for laryngeal cancer after (chemo)radiotherapy: a European Laryngological Society consensus statement

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    Purpose: To provide expert opinion and consensus on salvage carbon dioxide transoral laser microsurgery (CO2 TOLMS) for recurrent laryngeal squamous cell carcinoma (LSCC) after (chemo)radiotherapy [(C)RT]. Methods: Expert members of the European Laryngological Society (ELS) Cancer and Dysplasia Committee were selected to create a dedicated panel on salvage CO2 TOLMS for LSCC. A series of statements regarding the critical aspects of decision-making were drafted, circulated, and modified or excluded in accordance with the Delphi process. Results: The expert panel reached full consensus on 19 statements through a total of three sequential evaluation rounds. These statements were focused on different aspects of salvage CO2 TOLMS, with particular attention on preoperative diagnostic work-up, treatment indications, postoperative management, complications, functional outcomes, and follow-up. Conclusion: Management of recurrent LSCC after (C)RT is challenging and is based on the need to find a balance between oncologic and functional outcomes. Salvage CO2 TOLMS is a minimally invasive approach that can be applied to selected patients with strict and careful indications. Herein, a series of statements based on an ELS expert consensus aimed at guiding the main aspects of CO2 TOLMS for LSCC in the salvage setting is presented
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