457 research outputs found

    Brand gender and consumer-based brand equity on Facebook: The mediating role of consumer-brand engagement and brand love

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    Brand gender has been suggested as a relevant source of consumer-based brand equity (CBBE). The purpose of this paper is to deepen understanding of the relationship between brand gender and CBBE by analyzing the mediating roleofconsumer–brandengagement (CBE)andbrandlove(BL)onthisrelationship.Thisresearchwas conducted on Facebook, the dominant global social media platform. The hypotheses were tested using structural equation modeling. Results support 6 of the 9 hypotheses, with a significant relationship between analyzed constructs. This study advances prior work by showing that brand gender has an indirect and relevant impact on CBBE through BL and CBE. Therefore, this research confirms the advantages of clear gender positioning and extends prior research by suggesting that brands with a strong gender identity will encourage BL and CB

    Investigation of Dendrimer-based nanoparticles cellular uptake and cell tracking in a semiautomated microfluidic platform

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    A microfluidic device such as Kima Pump and Vena8 biochip is able to realize functions that are not easily imaginable in conventional biological analysis, such as highly parallel, sophisticated high-throughput analysis and single-cell analysis in a well-defined manner [1]. Cancer cell tracking within the microfluidic model will be achieved by grafting fluorescent label probe Fluorescein-5(6)-isothiocyanate (FITC) to dendrimer nanoparticles allowing cell visualization by immunofluorescent staining followed by fluorescence microscopy. In this study, synthesis and physicochemical characterization of Carboxymethyl-chitosan/poly(amidoamine) dendrimer nanoparticles (CMCht/PAMAM NPâ s) were performed[2].  Several cancer cell lines such as a HeLA (cervical carcinoma cell line), HTTC-116 (Colon Carcinoma) and Glioblastome cell line (GBM) were exposed to different concentrations of CMCht/PAMAM dendrimer nanoparticles over a period of 7d. After finding the adequate NP concentration, the internalization efficiency was tested, as well as cellular trafficking, in static and dynamic conditions (Kima Pump bioreactor).Portuguese Foundation for Science and Technology (FCT) through the project PEst­C/SAU/LA0026/20

    Oxygen conditioning effect on an in vitro co-culture model of tendon-to-bone interface

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    Tendon-to-bone interface comprises a heterotypic cellular niche. The native interface is hypovascular, suggesting that the junction is physiologically hypoxic. As it bridges tendon and bone, which require different oxygen concentrations, a tight coordination of different oxygen concentrations along the junction must be considered when trying to mimic and understand biological events occurring within the tissue. Herein, an optimized in vitro co-culture model of tendon-derived cells (hTDCs) and pre-osteoblasts (pre-OBs) [1] was used to study the effect of a restricted oxygen environment on cell behavior.Hospital da Prelada (Porto, Portugal) for lipoaspirates and tendon samples; ERC Grant CoG MagTendon nr 772817, the Project NORTE-01-0145-FEDER-000021, HORIZON 2020 under the TEAMING Grant agreement No 739572 - The Discoveries CTR and FCT - PhD grant of IC (PB/DB/128088/2016

    Optimization and establishment of a co-culture model to study cellular interactions in tendon-to-bone interface

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    Tendon detachment from its bony insertion is one of the most frequent injuries occurring in the musculoskeletal interface, constituting an unmet challenge in orthopaedics. Tendon-to-bone integration occurs at the enthesis, which is characterized by a complex structure organized in a gradient of cells and microenvironments. Hence, the maintenance of a heterotypic cellular niche is critical for tissue functionality and homeostasis. Replicating this unique complexity constitutes a challenge when addressing tendon-to-bone regeneration and interfacial tissue engineering strategies. Currently, mechanisms presiding to tendon-to-bone interface healing are not yet fully understood, particularly the interactions between tendon and bone cells in the orchestration of interfacial repair versus regeneration. Therefore, this study focused on the hypothesis that interactions between human tendon-derived cells (hTDCs) and pre-osteoblasts (pre-OB) can initiate a cascade of events, potentially leading to interfacial regeneration. Thus, hTDCs and pre-OB (pre-differentiated human adipose-derived stem cells) were used. Herein, five different ratios between basal and osteogenic media (100:0,75:25,50:50,25:75,0:100) were assessed to estimate their influence on cell behaviour and identify the ideal parameters for simultaneously supporting tenogenic and osteogenic differentiation before establishing a co-culture. Tenogenic and osteogenic differentiation were assessed through the expression of tendon and bone markers, mineralization (alizarin red, AZ) and alkaline phosphatase (ALP) quantification. Results showed that hTDCs exhibited osteogenic differentiation potential when cultured in the presence of osteogenic media, as demonstrated by an increase in ALP activity and mineralization. Pre-OB expressed osteogenic markers (OCN, OPN) in all media conditions confirming osteogenic commitment, which was simultaneously confirmed by ALP levels and AZ staining. Thus, three different conditions (100:0, 50:50, 0:100) were chosen for further studies in a direct contact co-culture system. Similarly to single cultures, a significant proliferation was observed in all conditions and mineralization was increased as soon as 7 days of culture. Additionally, osteogenic, tenogenic and interface-relevant markers will be assessed to study the effect of co-culture on phenotype maintenance. In summary, the present work addresses major limitations to clinical translation of cell-based therapies aiming at promoting interfacial regeneration. Particularly, we explored the influence of culture media on the maintenance of tenogenic and osteogenic niches, taking a basic and critical step towards the establishment of more complex cell-based systems. Acknowledgements Authors thank Fundação para a Ciência e Tecnologia in the framework of FCT-POPH-FSE, SFRH/BD/96593/2013 (RCA) and IF/00593/2015 (MEG); and to FCT/MCTES and the FSE/POCH, PD/59/2013 for PD/BD/128088/2016 (IC)Fundação para a Ciência e Tecnologia in the framework of FCT-POPH-FSE, SFRH/BD/96593/2013 (RCA) and IF/00593/2015(MEG); and to FCT/MCTES and the FSE/POCH, PD/59/2013 for PD/BD/128088/2016 (IC)info:eu-repo/semantics/publishedVersio

    Peptide-modified dendrimer nanoparticles for targeted therapy of colorectal cancer

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    Peptides have recently emerged as a promising class of targeting ligands forspecific drug delivery in cancer treatment, which avoid undesirable side effectsof the systemic administration of chemotherapeutics. Their conjugation withnanoparticles has been demonstrated to improve the functionality of peptidesresulting in a versatile platform for biomedical applications. In this work, thedevelopment of carboxymethylchitosan/poly(amidoamine) (CMCht/PAMAM)dendrimer nanoparticles functionalized with YIGSR laminin receptor bindingpeptide for the active targeting and specific delivery of therapeutic agents intocolorectal cancer cells is described. The successful functionalization isconfirmed by several physico-chemical characterization techniques. Theselectivity of the YIGSR-CMCht/PAMAM dendrimer nanoparticles is firstvalidated in vitro using a micropatterned array of 67 kDa laminin receptor.Next, the specificity of YIGSR-CMCht/PAMAM dendrimers nanoparticlestoward laminin receptor is further confirmed both in 2D and 3D settings usingHCT-116 colorectal cancer cells and L929 fibroblasts in co-culture. Finally,gemcitabine-loaded YIGSR-CMCht/PAMAM dendrimer nanoparticles inducea targeted mortality on HCT-116 cancer cells in a co-culture scenario. Overall,the study shows solid evidence that YIGSR laminin receptor binding peptidecoupled to CMCht/PAMAM dendrimer nanoparticles may be employed as ananticancerous target for the specific and intracellular delivery ofchemotherapeutic agents.This work was financially supported through the project FROnTHERA (NORTE-01-0145-FEDER-000023), Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); M.R.C. for her Ph.D. scholarship NORTE-08-5369-FSE-000044, funded by Programa Operacional Regional do Norte, Fundo Social Europeu, Norte 2020 TERM&SC and EMBO Short-Term Fellowship 7232. J.M.O. for his distinction attributed under the FCT Investigator program (IF/00423/2012 and IF/01285/2015; F.R.M. acknowledges FCT for her work contract under the Transitional Rule DL 57/2016 (CTTI-57/18-I3BS(5)). D.C. acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) under the program CEEC Individual 2017 (CEECIND/00352/2017). D.C. and S.C.K. for the Portuguese Foundation for Science and Technology (FCT) under the scope of the project 2MATCH (PTDC/BTMORG/28070/2017) funded by the Programa Operacional Regional do Norte supported by European Regional Development Funds (ERDF). This work is also partially supported by the IET Harvey Engineering Research Award 2018 (ENG ThE CANCER) and the European Union Framework Program for Research and Innovation Horizon 2020 on FoReCaST project under Grant Agreement No. 668983

    A semiautomated microfluidic platform for real-time investigation of nanoparticles' cellular uptake and cancer cells' tracking

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    Aims: develop a platform composed of labeled dendrimer nanoparticles and a microfluidic device for real-time monitoring of cancer cells fate. Materials and Methods: The physicochemical and biological characterization of the developed Carboxymethyl-chitosan/poly(amidoamine) (CMCht/PAMAM) dendrimer nanoparticles were performed using TEM, AFM, Zeta Sizer, DSC and cytotoxicity screening. Cancer cell lines derived from different tumor types, including HeLa (Cervical Carcinoma), HCT-116 (Colon Carcinoma) and U87MG (Glioblastoma), were exposed to different concentrations of CMCht/PAMAM dendrimer nanoparticles over a period of 3 days (MTS/DNA). Results: Nanoparticles were successfully modified with an average size of 50 nm. Internalization levels go from 87% to 100% in static and from 95% to 100% in dynamic conditions. Viability levels range from 95% to 100% in static and from 90% to 100% in dynamic conditions, being HCT the most sensitive to the presence of the NP. Conclusions: the results show different responses to the presence of 0.5 mg.mL-1 dendrimer nanoparticles when comparing static to dynamic conditions, with a tendency towards higher sensitivity when subjected to confinement. This work demonstrated that the proposed microfluidic-based platform allows real-time cell monitoring, which, upon more studies, namely the assessment of the drug release effect, could be used for cancer theranostics.FR Maia acknowledges ERC-2012-ADG 20120216–321266 (ComplexiTE) for her Postdoc scholarship. JM Oliveira thanks Portuguese Foundation for Science and Technology (FCT) for his distinction attributed under the FCT Investigator program (IF/00423/2012). BM Costa also thanks Portuguese Foundation for Science and Technology (PTDC/SAU-GMG/113795/2009 and IF/00601/2012 to BM Costa), Fundação Calouste Gulbenkian (BM Costa) and Liga Portuguesa Contra o Cancro (BM Costa). MR Carvalho also thanks the funding through the LA ICVS/3Bs project (UID/Multi/50026/2013). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.info:eu-repo/semantics/publishedVersio

    Fresh-cut melon quality during storage: an NMR study of water transverse relaxation time

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    Molecular mobility is a fundamental parameter which reflects the dynamic properties of food components and contributes to food degradation reactions comprehension. Fresh-cut fruits have become an important food market segment. However, processing of fruits promotes faster its physiological deterioration, biochemical changes and microbial degradation. The purpose of this work was to use NMR methodology as a tool to evaluate fresh-cut fruit quality, during storage at refrigerated conditions. The fresh-cut melon transverse relaxation time (T2) was measured for a period of 7 days of storage at 5 °C. The relationship between the obtained values, microstructure and quality parameters was investigated. In general, results show the existence of one class of water fluidity in the system, the one present in cells after processing. T2, a measure of this fluidity, is affected by the processing and storage time. Also, it is possible to find a close relationships between T2 and quality parameters of total colour difference (TCD), firmness and aw. As T2 increases TCD also increases, while firmness and aw decrease. These results highlight the usefulness of NMR methodology application in food science.Author Joana F. Fundo acknowledges Fundacao para a Ciencia e a Tecnologia (grant SFRH/BD/62176/2009). The authors acknowledge the Portuguese NMR Network and Strategic Project PEst-C/CTM/LA0025/2013-14. This work was supported by National Funds from FCT through project PEst-OE/EQB/LA0016/201

    Glial Cell Line-Derived Neurotrophic Factor-Loaded CMCht/PAMAM Dendrimer Nanoparticles for Peripheral Nerve Repair

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    (1) Background: Peripheral nerve injuries represent a major clinical challenge. If nerve ends retract, there is no spontaneous regeneration and grafts are required to proximate the nerve ends and give continuity to the nerve. (2) Methods: GDNF-loaded NPs were characterized physicochemically. For that, NPs stability at different pH’s was assessed, and GDNF release was studied through ELISA. In vitro studies are performed with Schwann cells, and the NPs are labeled with fluorescein-5(6)-isothiocyanate for uptake experiments with SH-SY5Y neural cells. (3) Results: GDNF-loaded NPs are stable in physiological conditions, releasing GDNF in a two-step profile, which is beneficial for nerve repair. Cell viability is improved after 1 day of culture, and the uptake is near 99.97% after 3 days of incubation. (4) Conclusions: The present work shows the efficiency of using CMCht/PAMAM NPs as a GDNF-release system to act on peripheral nerve regeneration.This work was supported by the Portuguese Foundation for Science and Technology for the funds provided under the distinction attributed to JMO (IF/01285/2015) and the project NanOptoNerv (ref. PTDC/NAN-MAT/29936/2017). The work was also supported by the European Commission and FEDER program, the JUSTHera project (NORTE-01-0145-FEDER-000055), and the 0624_2IQBIONEURO_6_E project (Inter-regional cooperation program VA Spain-Portugal POCTEP 2014-2020)

    Sugarcane straw polyphenols as potential food and nutraceutical ingredient

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    The sugarcane processing industry generates a large amount of straw, which has a negative environmental impact, and high costs are associated with their elimination, wasting their potential bioactive value attributed to their richness in polyphenols. In this study, an ethanolic extract produced from sugarcane straw was screened for its phenolic compounds content, and the potential use of this extract in the development of a food ingredient was further evaluated. Fifty different secondary metabolites belonging to the hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids were identified by liquid chromatography–electrospray ionization–ultrahigh-resolution—quadrupole time of flight–mass spectrometry (LC-ESI-UHR-QqTOF-MS). The predominant phenolic compounds found were 4-hydroxybenzaldehyde, chlorogenic acid, and 5-O-feruloylquinic acid. The obtained extracts showed strong potential as food preservatives by exhibiting (a) antioxidant activity using both 2.2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt radical cation (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods; and (b) antimicrobial capacity, with a minimum inhibitory concentration of 50 mg/mL for Staphylococcus aureus, 74% inhibition for Bacillus cereus, and 44% for Salmonella enterica; and (c) the capacity to inhibit a food browning enzyme, tyrosinase (28–73% for 1–8 mg/ mL). Moreover, the extracts showed antidiabetic potential by inhibiting the enzymes α-glucosidase (15–38% for 1.25–5.00 mg/mL) and dipeptidyl peptidase-IV (DPP-IV) (62–114% for 0.31–5.00 mg/mL). The extract (0.625 mg/mL) also exhibited the capacity to reduce proinflammatory mediators (i.e., interleukins 6 and 8, and tumor necrosis factor alpha) when Caco-2 cells were stimulated with interleukin 1 beta. Thus, sugarcane straw extract, which is rich in phenolic compounds, showed high potential to be used in the development of food-preservative ingredients owing to its antioxidant and antimicrobial potential, and to be explored as a food supplement in diabetes prevention and as coadjuvant to reduce intestinal inflammation by reducing proinflammatory mediators.info:eu-repo/semantics/publishedVersio
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