1,262 research outputs found

    Adhesion Strength of Aluminum on Metallized Plastic Films Used in Flexible Packages - Development and Validation of a Test Procedure

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    OPP and OPET metallized films are widely used as substrates in multi layer packages, since they bring together good mechanical properties and barrier to gases and water vapor, which are damaged with delamination of the film layers, together with the visual appearance and package integrity. One of the main factors that affect the package delamination is the adhesion strength of aluminum layer to the polymeric substrate, a parameter for which there is no standard procedure to quantify. The aim of this work was to establish and validate a procedure to determine the adhesion strength of the aluminum to the polymer. This test procedure was carried out using experimental design with fixed and variables parameters with two levels for each variable. The test procedure was stable, robust and replicable. It consisted basically of the heat sealing of a plastic film to the metallized sample surface, under specific temperature/time/pressure conditions and the measuring of adhesion strength of metallization in a universal test machine running at specific angle and speed.21323323

    A Diagnostic Algorithm for Posterior Fossa Tumors in Children: A Validation Study

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    BACKGROUND AND PURPOSE: Primary posterior fossa tumors comprise a large group of neoplasias with variable aggressiveness and short and long-term outcomes. This study aimed to validate the clinical usefulness of a radiologic decision flow chart based on previously published neuroradiologic knowledge for the diagnosis of posterior fossa tumors in children. MATERIALS AND METHODS: A retrospective study was conducted (from January 2013 to October 2019) at 2 pediatric referral centers, Children's Hospital of Philadelphia, United States, and Great Ormond Street Hospital, United Kingdom. Inclusion criteria were younger than 18 years of age and histologically and molecularly confirmed posterior fossa tumors. Subjects with no available preoperative MR imaging and tumors located primarily in the brain stem were excluded. Imaging characteristics of the tumors were evaluated following a predesigned, step-by-step flow chart. Agreement between readers was tested with the Cohen κ, and each diagnosis was analyzed for accuracy. RESULTS: A total of 148 cases were included, with a median age of 3.4 years (interquartile range, 2.1-6.1 years), and a male/female ratio of 1.24. The predesigned flow chart facilitated identification of pilocytic astrocytoma, ependymoma, and medulloblastoma sonic hedgehog tumors with high sensitivity and specificity. On the basis of the results, the flow chart was adjusted so that it would also be able to better discriminate atypical teratoid/rhabdoid tumors and medulloblastoma groups 3 or 4 (sensitivity = 75%-79%; specificity = 92%-99%). Moreover, our adjusted flow chart was useful in ruling out ependymoma, pilocytic astrocytomas, and medulloblastoma sonic hedgehog tumors. CONCLUSIONS: The modified flow chart offers a structured tool to aid in the adjunct diagnosis of pediatric posterior fossa tumors. Our results also establish a useful starting point for prospective clinical studies and for the development of automated algorithms, which may provide precise and adequate diagnostic tools for these tumors in clinical practice

    Girişimciliğin ilk aşamasında finansman temin yolları ve finansman temininde karşılaşılan sorunlar: Gaziantep ilinde bir uygulama

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    Bugün işletmeler gelişen dünya pazarlarında rekabette bulunarak ekonomik ve finansal açıdan avantaj sağlamaktadırlar. İşletmeler, girişimcilerin temel özellikleri ile teknolojiyi kullanan ve geliştiren işletmeler olarak ülkelerin kalkınmasında önemli rol oynamaktadır. Teknolojik yeniliklerin yanında inovasyona da yatırım yaparak gelişimlerini tamamlarlar. Ancak her alanda olduğu gibi, girişimciler finansal açıdan da sorunlarla karşılaşmaktadırlar. Dolayısıyla işletme sayısının artarak ülkeye katkıda bulunabilmesi için finansman teminindeki sorunları farklı olan girişimcilerin desteklenmeleri ve yönlendirilmeleri gerekmektedir. Bu noktada, girişimcileri desteklemek amacıyla kamu kurum ve kuruluşları ve diğer kuruluşlar faaliyetlerini sürdürmektedir. Bu araştırmanın temel amacı, girişimciliğin ilk aşamasında finans temin yollarının belirlenerek finansman temin yönteminde karşılaşılan sorunları ortaya koymaktır. Bununla birlikte, bu çalışmada Türkiye’de girişimciliğin temel özellikleri, girişimcilik finansman türleri ve finansman temininde karşılaşılan sorunlara yönelik önerilerin sunulması amaçlanmaktadır. Araştırma kapsamında nitel ve nicel araştırma yöntemleri uygulanmıştır. Nicel araştırma kapsamında, 408 girişimciye anket uygulanmış, nitel araştırma kapsamında ise 180 girişimciyle yüz yüze görüşmeler yapılmıştır. Araştırma yöntemlerinden elde edilen veriler, çeşitli istatistiksel analizlere tabi tutulmuştur. Girişimciliğin ilk aşamasında, girişimcilerin finansman temininde karşılaştıkları sorunlar belirlenerek, bu sorunlara yönelik çözüm önerilerinde bulunulmuştur. Bu araştırmanın sonucunda, girişimciliğin ilk aşamasında, girişimcilerin finansman temin yöntemi konusunda yeterli derecede bilgi sahibi olmadıkları ve kendi kaynaklarını daha çok kullandıkları tespit edilmiştir

    Mesenchymal stem cells secretome-induced axonal outgrowth is mediated by BDNF

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    Mesenchymal stem cells (MSCs) have been used for cell-based therapies in regenerative medicine, with increasing importance in central and peripheral nervous system repair. However, MSCs grafting present disadvantages, such as, a high number of cells required for transplantation and low survival rate when transplanted into the central nervous system (CNS). In line with this, MSCs secretome which present on its composition a wide range of molecules (neurotrophins, cytokines) and microvesicles, can be a solution to surpass these problems. However, the effect of MSCs secretome in axonal elongation is poorly understood. In this study, we demonstrate that application of MSCs secretome to both rat cortical and hippocampal neurons induces an increase in axonal length. In addition, we show that this growth effect is axonal intrinsic with no contribution from the cell body. To further understand which are the molecules required for secretome-induced axonal outgrowth effect, we depleted brain-derived neurotrophic factor (BDNF) from the secretome. Our results show that in the absence of BDNF, secretome-induced axonal elongation effect is lost and that axons present a reduced axonal growth rate. Altogether, our results demonstrate that MSCs secretome is able to promote axonal outgrowth in CNS neurons and this effect is mediated by BDNF.European Regional Development Fund (ERDF), through the Centro 2020 Regional Operational Programme under project CENTRO-01–0145-FEDER-000008:BrainHealth 2020, and through the COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation and Portuguese national funds via FCT – Fundação para a Ciência e a Tecnologia, I.P., under projects PTDC/SAU-NEU/104100/2008, EXPL/NEU-NMC/0541/2012 and UID/NEU/04539/2013. This work was also funded by Marie Curie Actions - International reintegration grant #249288, 7th Framework programme, EU. Partially funded by Prémios Santa Casa Neurociências - Prize Melo e Castro for Spinal Cord Injury Research; Portuguese Foundation for Science and Technology (IF Development Grant to A.J.S.); NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme; by FEDER funds, through the Competitiveness Factors Operational Programme (COMPETE), and by national funds, through the Foundation for Science and Technology (FCT), under the scope of the project POCI-01-0145-FEDER-007038. The authors would also like to acknowledge Prof. J.E. Davies from the Institute of Biomaterials and Biomedical Engineering at the University of Toronto, Canada, for kindly providing some of the HUCPVCs lots used in the present workinfo:eu-repo/semantics/publishedVersio

    Relationship Between Sonic Hedgehog Protein, Brain-Derived Neurotrophic Factor and Oxidative Stress in Autism Spectrum Disorders

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    The etiology of autism spectrum disorders (ASD) is not well known but oxidative stress has been suggested to play a pathological role. We report here that the serum levels of Sonic hedgehog (SHH) protein and brain-derived neurotrophic factor (BDNF) might be linked to oxidative stress in ASD. By using the whole blood or polymorphonuclear leukocytes, we demonstrated that autistic children produced a significantly higher level of oxygen free radicals (OFR). In addition, we found significantly higher levels of serum SHH protein in children with mild as well as severe form of autism. We also found that the serum level of BDNF was significantly reduced in autistic children with mild form of the disorder but not with severe form of the disorder. Our findings are the first to report a correlation between SHH, BDNF and OFR in autistic children, suggesting a pathological role of oxidative stress and SHH in autism spectrum disorders
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