44 research outputs found

    Measuring consumer perceptions of online shopping convenience

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    The aim of this master thesis is to identify which dimensions of convenience affect consumers’ intention of using online shopping. Also it explores a conceptual model to measuring consumer perceptions of online shopping convenience. This paper contains prospects about online consumer behavior, and the results have important implications for retailers, managers and marketers, related to online shopping strategies. An empirical investigation was carried out to test the hypotheses. In order to answer the research question, data collection was done through a web-based survey with a convenient sample as a means to collect customers’ feedback, opinion, feelings, attitudes, and perceptions about their last online shopping experience. The findings were further discussed in the light of existing literature. The sample includes 250 young Portuguese anonymous participants. It was used a Confirmatory Factor Analysis (CFA) in the scale validation for the analysis and measurement of specific constructs and a Structural Equation Model (SEM) in order to test the relationships of the model. The results reveal that the model proposed Possession, Transaction and Evaluation are the dimensions with more influence in online shopping convenience. The outcomes of this study help to understand which dimensions of online convenience prevent or encourage the use intention of online shopping. The results not only help develop a better understanding of online shopping theories for researchers, but they also offer viable knowledge to those involved in promoting online shopping to potential purchasers

    Adesão das pessoas com diabetes tipo 1 às atividades de autocuidado

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    Objective: to assess the adherence of people with type 1 diabetes to self-care activities. Method: quantitative study with 60 diabetics, from Porto, Portugal. The Self-Care Scale for Diabetes in its version translated and adapted to Portuguese was applied in January to February 2019. Results: respondents are mostly young (36.7%), employed (63.4%), female (73.3%), married (36.7%), high educated (60.0%) and diagnosed with recent diabetes (50.0%). Most have good mean adherence to self-care behaviors related to food (5.0), blood glucose monitoring (6.8), foot care (5.6) and medication (6.4). Regarding physical activity (2.6) and smoking, 73.3% of respondents say they smoked a cigarette in the last seven days lower adherence was identified. Conclusions: there is a need to develop educational programs to ensure a higher adherence to healthy lifestylesinfo:eu-repo/semantics/publishedVersio

    The influence of pre-gestational body mass index and physical activity patterns on maternal, delivery and newborn outcomes in a sample of portuguese pregnant women: a retrospective cohort study.

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    There is a linear association between pregestational body mass index (BMI) and almost all adverse pregnancy outcomes. Pregnancy is “a window of opportunities” in terms of changing behavior and improving awareness of healthy living. The proper assessment of physical activity levels, during pregnancy, determines trends, health benefits, and their effects over time. This study aims to describe maternal physical activity levels, stratified by pregestational BMI, verify the accomplishment of physical activity recommendations in pregnant women, and correlate pregestational BMI and physical activity accomplishment with maternal, delivery, and neonatal parameters.  A retrospective cohort study was carried out with 103 pregnant women. Physical activity levels were evaluated using a questionnaire and accelerometry. Pregestational BMI was obtained through the Quetelet formula and used the American College of Sports Medicine’s guidelines were used to determine physical activity accomplishment levels. Continuous data were presented as mean and standard deviation and categorical data as numbers and percentages. The F test was used to examine the differences between groups. Pregnant women in the sample spent 42.9% of their time on household activities, and for pregnant women with obesity, 91.5% of the time was spent on sedentary activities. Women with normative BMI had higher levels of moderate-intensity activities. Only 15.8% of participants with obesity reached the international recommendations for physical activity practice and women who accomplished physical activity recommendations gained less weight during pregnancy. A high percentage of pre-obesity and obese pregnant women exceeded the recommendations for gestational weight gain and the gestational diabetes prevalence was higher in the obesity group (p = 0.03 between groups). Regarding delivery and neonatal parameters (Apgar score 1st, Apgar score 5th, birth weight, length and head circumference), no statistical differences were found when adjusted to a gestational week at birth, between BMI (p = 0.58; p = 0.18; p = 0.60; p = 0.34; p = 0.34, respectively) or physical activity (p = 0.12; p = 0.15; p = 0.83; p = 0.70; p = 0.70, respectively) groups. Pregnant women with obesity, exhibit high levels of sedentary behavior, a high prevalence of gestational diabetes, and exceed recommended gestational weight gain. Healthcare professionals have a crucial role in promoting regular physical activity and lifestyle changes before and during pregnancy.info:eu-repo/semantics/publishedVersio

    Enginnering cardiac tissue using human induced pluripotent stem cell derivatives: Proteomic characterization of co-cultures of cardiomyocytes and endothelial cells

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    Prediction of cardiac toxicity effect is extremely relevant in the development of new drugs for different medical applications. In this way, it is important to develop more predictable human cell-based models which physiologically better mimic the human heart and allow the prediction of this toxic effect as well as establish the tools that enable the characterization of these complex cell models. To recreate engineered cardiac tissue, it is essential to reproduce the complexity of the heart by resorting to different cell types. Cardiomyocytes (CMs) are functional contractile units of the heart, and it is known that their communication with endothelial cells (ECs) is crucial for cardiac homeostasis. The aim of this study is to recreate a human pluripotent stem cells (hiPSC)-based cardiac tissue model and evaluate the impact of communication between both cell types on the phenotype of CMs. Co-cultures of hiPSC-CM and hiPSC-EC were established and maintained for 12 days as confirmed by immunofluorescence microscopy. Quantitative whole-proteome analysis was performed using SWATH Mass Spectrometry tools to compare the conditions of hiPSC-CM mono-culture and the co-culture of hiPSC-CM and hiPSC-EC. Our data showed relative increase of expression ratios of morphological maturation-related cardiac proteins in hiPSC-CM co-cultures. In particular, the expression ratios of MYH7/MYH6, MYL2/MYL7, TNNI3/TNNI1 increased 2.4-, 5.1-, and 5-fold, respectively, when compared to the mono-culture condition, indicating that in the presence of hiPSC-EC, hPSC-CM display a more adult- and ventricular- like phenotype. Changes in the extracellular matrix composition were also observed, especially related with the increased expression of ECM proteins in co-culture condition namely, collagens I and III (8.6-fold and 6-fold, respectively), fibronectin (3.5-fold) and thrombospondin-4 (2.5-fold). Other growth factors attributed to the extracellular space (e.g. CTGF, PAI1, CRTAP, IGFBP7, and NPPB) that may be responsible for the communication between both cell types have also shown to be up-regulated in the co-culture condition. The presence of a SMA+ (myofibroblast-like) population in the co-culture condition was observed by immunofluorescence microscopy images, which is in agreement with the more complex and fibrotic extracellular matrix found by whole proteome analysis. Ultrastructure characterization of CMs was carried out by transmission electron microscopy. In both conditions, hiPSC-CM displayed aligned myofibrils composed by sarcomeres with organized Z-disks, A- and I-bands, intercalated discs between adjacent cells as well as abundant mitochondria. Noteworthy, sarcomere length was higher in hiPSC-CM cultured with hiPSC-EC, suggesting structural changes associated with cardiomyocyte maturation. Calcium imaging is being performed to evaluate calcium handling of hiPSC-CMs and their response to drugs. All together our data revealed that promoting the communication of hiPSC-CM and hiPSC-EC induced structural changes in hiPSC-CM associated with maturation. This study provides important insights towards the development of more complex cardiac tissues and establishes potent analytical tools for the characterization of these models. This work was supported by Fundação para a Ciência e Tecnologia (FCT)-funded project CARDIOSTEM (MITP-TB/ECE/0013/2013); and iNOVA4Health UID/Multi/04462/2013, a program supported by FCT/Ministério da Educação e Ciência, through national funds and cofounded by FEDER under the PT2020 Partnership Agreement. BA. was supported by FCT Grant SFRH/BD/52475/201

    Human Extracellular-Matrix Functionalization of 3D hiPSC-Based Cardiac Tissues Improves Cardiomyocyte Maturation

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    The work here presented was funded by Fundacao para a Ciencia e Tecnologia (FCT) projects NETDIAMOND (SAICTPAC/0047/2015), financially supported by FEEI-Lisboa2020 and FCT/POCI-01-0145-FEDER-016385, and MetaCardio (PTDC/BTM-SAL/32566/2017); iNOVA4-Health -UIDB/04462/2020 and UIDP/04462/2020, a program financially supported by FCT/Ministerio da Ciencia, Tecnologia e Ensino Superior, through national funds is acknowledged; Funding from INTERFACE Programme, through the Innovation, Technology and Circular Economy Fund (FITEC), is gratefully acknowledged; and EU-funded projects BRAV3 (H2020, ID:874827) and ERAatUC (ref. 669088). HVA, AFL, and DS were financed by FCT Grants SFRH/BPD/120595/2016 and PD/BD/139078/2018 and PD/BD/106051/2015, respectively.Human induced pluripotent stem cells (hiPSC) possess significant therapeutic potential due to their high self-renewal capability and potential to differentiate into specialized cells such as cardiomyocytes. However, generated hiPSC-derived cardiomyocytes (hiPSC-CM) are still immature, with phenotypic and functional features resembling the fetal rather than their adult counterparts, which limits their application in cell-based therapies, in vitro cardiac disease modeling, and drug cardiotoxicity screening. Recent discoveries have demonstrated the potential of the extracellular matrix (ECM) as a critical regulator in development, homeostasis, and injury of the cardiac microenvironment. Within this context, this work aimed to assess the impact of human cardiac ECM in the phenotype and maturation features of hiPSC-CM. Human ECM was isolated from myocardium tissue through a physical decellularization approach. The cardiac tissue decellularization process reduced DNA content significantly while maintaining ECM composition in terms of sulfated glycosaminoglycans (s-GAG) and collagen content. These ECM particles were successfully incorporated in three-dimensional (3D) hiPSC-CM aggregates (CM+ECM) with no impact on viability and metabolic activity throughout 20 days in 3D culture conditions. Also, CM+ECM aggregates displayed organized and longer sarcomeres, with improved calcium handling when compared to hiPSC-CM aggregates. This study shows that human cardiac ECM functionalization of hiPSC-based cardiac tissues improves cardiomyocyte maturation. The knowledge generated herein provides essential insights to streamline the application of ECM in the development of hiPSC-based therapies targeting cardiac diseases.publishersversionpublishe

    Inhibition of IL-10 Production by Maternal Antibodies against Group B Streptococcus GAPDH Confers Immunity to Offspring by Favoring Neutrophil Recruitment

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    Group B Streptococcus (GBS) is the leading cause of neonatal pneumonia, septicemia, and meningitis. We have previously shown that in adult mice GBS glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an extracellular virulence factor that induces production of the immunosuppressive cytokine interleukin-10 (IL-10) by the host early upon bacterial infection. Here, we investigate whether immunity to neonatal GBS infection could be achieved through maternal vaccination against bacterial GAPDH. Female BALB/c mice were immunized with rGAPDH and the progeny was infected with a lethal inoculum of GBS strains. Neonatal mice born from mothers immunized with rGAPDH were protected against infection with GBS strains, including the ST-17 highly virulent clone. A similar protective effect was observed in newborns passively immunized with anti-rGAPDH IgG antibodies, or F(ab')2 fragments, indicating that protection achieved with rGAPDH vaccination is independent of opsonophagocytic killing of bacteria. Protection against lethal GBS infection through rGAPDH maternal vaccination was due to neutralization of IL-10 production soon after infection. Consequently, IL-10 deficient (IL-10−/−) mice pups were as resistant to GBS infection as pups born from vaccinated mothers. We observed that protection was correlated with increased neutrophil trafficking to infected organs. Thus, anti-rGAPDH or anti-IL-10R treatment of mice pups before GBS infection resulted in increased neutrophil numbers and lower bacterial load in infected organs, as compared to newborn mice treated with the respective control antibodies. We showed that mothers immunized with rGAPDH produce neutralizing antibodies that are sufficient to decrease IL-10 production and induce neutrophil recruitment into infected tissues in newborn mice. These results uncover a novel mechanism for GBS virulence in a neonatal host that could be neutralized by vaccination or immunotherapy. As GBS GAPDH is a structurally conserved enzyme that is metabolically essential for bacterial growth in media containing glucose as the sole carbon source (i.e., the blood), this protein constitutes a powerful candidate for the development of a human vaccine against this pathogen

    Impact of tumor size on the difficulty of laparoscopic left lateral sectionectomies

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    Impact of liver cirrhosis, severity of cirrhosis and portal hypertension on the difficulty of laparoscopic and robotic minor liver resections for primary liver malignancies in the anterolateral segments

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