6,613 research outputs found
Rewarding the quantity of peer review could harm biomedical research
Voluntary peer review is generally provided by researchers as a duty or service to their disciplines. They commit their expertise, knowledge and time freely without expecting rewards or compensation. Peer review can be perceived as a reciprocal mission that aims to safeguard the quality of publications by helping authors improve their manuscripts. While voluntary peer review adds value to research, rewarding the quantity or the volume of peer review is likely to lure academics into providing poor quality peer review. Consequently, the quantity of peer review may increase, but at the expense of quality, which may lead to unintended consequences and might negatively affect the quality of biomedical publications. This paper aims to present evidence that while voluntary peer review may aid researchers, pressurized peer review may create a perverse incentive that negatively affects the integrity of the biomedical research record. We closely examine one of the proposed models for rewarding peer review based on the quantity of peer review reports. This article also argues that peer review should remain a voluntary mission, and should not be prompted by the need to attain tenure or promotion
Engineering a Vascularized 3D Hybrid System to Model Tumor-Stroma Interactions in Breast Cancer
The stromal microenvironment of breast tumors, namely the vasculature, has a key role in tumor development and metastatic spread. Tumor angiogenesis is a coordinated process, requiring the cooperation of cancer cells, stromal cells, such as fibroblasts and endothelial cells, secreted factors and the extracellular matrix (ECM). In vitro models capable of capturing such complex environment are still scarce, but are pivotal to improve success rates in drug development and screening. To address this challenge, we developed a hybrid alginate-based 3D system, combining hydrogel-embedded mammary epithelial cells (parenchymal compartment) with a porous scaffold co-seeded with fibroblasts and endothelial cells (vascularized stromal compartment). For the stromal compartment, we used porous alginate scaffolds produced by freeze-drying with particle leaching, a simple, low-cost and non-toxic approach that provided storable ready-to-use scaffolds fitting the wells of standard 96-well plates. Co-seeded endothelial cells and fibroblasts were able to adhere to the surface, spread and organize into tubular-like structures. For the parenchymal compartment, a designed alginate gel precursor solution load with mammary epithelial cells was added to the pores of pre-vascularized scaffolds, forming a hydrogel in situ by ionic crosslinking. The 3D hybrid system supports epithelial morphogenesis in organoids/tumoroids and endothelial tubulogenesis, allowing heterotypic cell-cell and cell-ECM interactions, while presenting excellent experimental tractability for whole-mount confocal microscopy, histology and mild cell recovery for down-stream analysis. It thus provides a unique 3D in vitro platform to dissect epithelial-stromal interactions and tumor angiogenesis, which may assist in the development of selective and more effective anticancer therapies.We would like to acknowledge FEDER – Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 – Operational Programme Competitiveness and Internationalization (POCI), Portugal 2020, and Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of Project ANGIONICHE (POCI-01-0145-FEDER-028744 and PTDC/BTMMAT/28744/2017). The authors thank FCT for research contract DL 57/2016/CP1360/CT0006 (SB), junior research contract in the framework of the project Angioniche (AT), and IF research position IF/00296/2015 (CB)
Marketing of breastmilk substitutes and early breastfeeding practices among native and migrant women
There is a large body of evidence regarding the benefits of breastfeeding for mothers and their children. However, the influence of marketing of breastmilk substitutes on breastfeeding practices remains a big concern. The aim of this study is to examine the association between exposure to different breastmilk substitutes market factors and never breastfeeding or dropping exclusive breastfeeding within 1 month postpartum, comparing migrant with native women. Methods: This study is part of the project baMBINO, an ongoing research on perinatal health among migrant and native women in Portugal. Women with a live-birth and aged ≥ 18 years were recruited in 32 Portuguese public hospitals during admission for delivery. Data on breastfeeding practices and exposure to market factors were collected by telephone interviews at 1-3 months postpartum. According to their feeding practices within 1 month after delivery, women were classified into two categories: those who have never breastfed or have dropped exclusive breastfeeding, and those who have maintained exclusive breastfeeding. Five market factors were assessed: free samples, discounts, television, newspaper/magazine, and shop/ pharmacy advertisement. Logistic regression models were used to study the association between each market factor and early breastfeeding practices, adjusting for maternal age, education, parity, mode of delivery, and skin-to-skin contact in the first hour after birth. All analyses were stratified by women’s country of birth (native vs. migrant). Adjusted odds-ratio (aOR) and a respective 95% confidence interval (95%CI) were obtained. Results: Out of 539 natives and an equal number of migrant women, 43.4% and 36.7%, respectively, have either never breastfed or dropped exclusive breastfeeding within 1 month postpartum. After adjustment, natives exposed to free samples were more likely to never breastfeed or drop exclusive breastfeeding within 1 month after delivery (aOR = 1.90, 95%CI: 1.06-3.42), while those exposed to shop/pharmacy advertisement were less likely to (aOR = 0.62, 95%CI 0.43-0.89). Conversely, migrants exposed to newspaper/magazine advertisement were less likely to never breastfeed or drop exclusive breastfeeding within 1 month postpartum (aOR = 0.54, 95%CI 0.31-0.95). Conclusions/Recommendations: Our results revealed differences in the effect of market factors on breastfeeding practices between native and migrant women, which might be explained by cultural factors. Future research should investigate the mechanisms underlying the direction of association between specific market factors and early breastfeeding practices.info:eu-repo/semantics/publishedVersio
Marketing of breastmilk substitutes and early breastfeeding practices among native and migrant women
There is a large body of evidence regarding the benefits of breastfeeding for mothers and their children. However, the influence of marketing of breastmilk substitutes on breastfeeding practices remains a big concern. The aim of this study is to examine the association between exposure to different breastmilk substitutes market factors and never breastfeeding or dropping exclusive breastfeeding within 1 month postpartum, comparing migrant with native women. Methods: This study is part of the project baMBINO, an ongoing research on perinatal health among migrant and native women in Portugal. Women with a live-birth and aged ≥ 18 years were recruited in 32 Portuguese public hospitals during admission for delivery. Data on breastfeeding practices and exposure to market factors were collected by telephone interviews at 1-3 months postpartum. According to their feeding practices within 1 month after delivery, women were classified into two categories: those who have never breastfed or have dropped exclusive breastfeeding, and those who have maintained exclusive breastfeeding. Five market factors were assessed: free samples, discounts, television, newspaper/magazine, and shop/ pharmacy advertisement. Logistic regression models were used to study the association between each market factor and early breastfeeding practices, adjusting for maternal age, education, parity, mode of delivery, and skin-to-skin contact in the first hour after birth. All analyses were stratified by women’s country of birth (native vs. migrant). Adjusted odds-ratio (aOR) and a respective 95% confidence interval (95%CI) were obtained.
Results: Out of 539 natives and an equal number of migrant women, 43.4% and 36.7%, respectively, have either never breastfed or dropped exclusive breastfeeding within 1 month postpartum. After adjustment, natives exposed to free samples were more likely to never breastfeed or drop exclusive breastfeeding within 1 month after delivery (aOR = 1.90, 95%CI: 1.06-3.42), while those exposed to shop/pharmacy advertisement were less likely to (aOR = 0.62, 95%CI 0.43-0.89). Conversely, migrants exposed to newspaper/magazine advertisement were less likely to never breastfeed or drop exclusive breastfeeding within 1 month postpartum (aOR = 0.54, 95%CI 0.31-0.95). Conclusions/Recommendations: Our results revealed differences in the effect of market factors on breastfeeding practices between native and migrant women, which might be explained by cultural factors. Future research should investigate the mechanisms underlying the direction of association between specific market factors and early breastfeeding practices.info:eu-repo/semantics/publishedVersio
Size-dependent bandgap and particle size distribution of colloidal semiconductor nanocrystals
A new analytical expression for the size-dependent bandgap of colloidal
semiconductor nanocrystals is proposed within the framework of the finite-depth
square-well effective mass approximation in order to provide a quantitative
description of the quantum confinement effect. This allows one to convert
optical spectroscopic data (photoluminescence spectrum and absorbance edge)
into accurate estimates for the particle size distributions of colloidal
systems even if the traditional effective mass model is expected to fail, which
occurs typically for very small particles belonging to the so-called strong
confinement limit. By applying the reported theoretical methodologies to CdTe
nanocrystals synthesized through wet chemical routes, size distributions are
inferred and compared directly to those obtained from atomic force microscopy
and transmission electron microscopy. This analysis can be used as a
complementary tool for the characterization of nanocrystal samples of many
other systems such as the II-VI and III-V semiconductor materials.Comment: 9 pages, 5 figure
The effect of aluminium nanocoating and water pH value on the wettability behavior of an aluminium surface
Experimental investigation was performed to highlight the influence of ionic bounding and surface roughness effects on the surface wettability. Nanocoating technique via e-beam physical vapor deposition process was used to fabricate aluminium (Al) film of 50, 100, and 150 nm on the surface of an Al substrate. Microstructures of the samples before and after deposition were observed using an atomic force microscopy. A goniometer device was later on used to examine the influence of surface topography on deionised water of pH 4, 7 and 9 droplets at a temperature ranging from 10 °C to 60 °C through their contact angles with the substrate surface, for both coated and uncoated samples. It was found that, although the coated layer has reduced the mean surface roughness of the sample from 10.7 nm to 4.23 nm, by filling part of the microstructure gaps with Al nanoparticles, the wettability is believed to be effected by the ionic bounds between the surface and the free anions in the fluid. As the deionised water of pH 4, and 9 gave an increase in the average contact angles with the increase of the coated layer thickness. On the other hand, the deionised water of pH 7 has showed a negative relation with the film thickness, where the contact angle reduced as the thickness of the coated layer was increased. The results from the aforementioned approach had showed that nanocoating can endorse the hydrophobicity (unwitting) nature of the surface when associated with free ions hosted by the liquid
Hygienic quality of dehydrated aromatic herbs marketed in Southern Portugal
Dehydrated aromatic herbs are highly valued ingredients, widely used at home level and by food processing industry, frequently added to a great number of recipes in the Mediterranean countries. Despite being considered low-moisture products and classified as GRAS, during pre and post-harvesting stages of production they are susceptible of microbial contamination. In Europe an increasing number of food recalls and disease outbreaks associated with dehydrated herbs have been reported in recent years. In this study the microbial quality of 99 samples of aromatic herbs (bay leaves, basil, coriander, oregano, parsley, Provence herbs, rosemary and thyme) collected from retails shops in the region of Algarve (Southern Portugal) was assessed. All the samples were tested by conventional methods and were assayed for the total count of aerobic mesophilic microorganisms, Salmonella spp., Escherichia coli, coagulase-positive staphylococci and filamentous fungi. Almost 50 % of the herbs did not exceed the aerobic mesophilic level of 104 CFU/g. The fungi count regarded as unacceptable (106 CFU/g) was not found in any of the tested herbs, while 84 % of the samples ranged from ≤102 to 104 CFU/g. No sample was positive for the presence of Salmonella spp., Escherichia coli and staphylococci. The results are in compliance with the European Commission criteria although they point out to the permanent need of surveillance on the good standards of handling/cooking practices as well as the importance of avoiding contamination at production, retailing and distribution. The microbiological hazards associated with the pathogenic and toxigenic microbiota of dried herbs remain as a relevant public health issue, due to the fact that they are added to foods not submitted to any following lethal procedure. Control measures should be adopted in order to ensure that all phases of their supply chain respect the food safety standards.FCT: UID/BIA/04325/2019.info:eu-repo/semantics/publishedVersio
Tobacco use during pregnancy among native and migrant women in Portugal. Results from the bambino study
Tobacco use is a major modifiable risk factor of adverse maternal and fetal health outcomes. Being a migrant has been associated with lower risk of smoking during pregnancy. However, it remains a matter of debate whether such association could be explained by other socio-demographic characteristics or whether such effect remains or increases according to the length of stay in the host country.
This study examined the differences in maternal smoking prevalence between native, long-term and recent migrant women in Portugal.
METHODS: This study was derived from baMBINO, a national project grounded on 32 public maternity units in mainland Portugal aiming to investigate the differences in perinatal healthcare and outcomes among migrant and native women. Recruitment took place during admission for delivery, inviting both native and foreign-born women. Participants included in this analysis (n=1107) were classified according to their country of birth and length of stay in Portugal into: native (Portuguese-born), recent migrant (foreign-born women who spent 10 years or less in Portugal), and long-term migrants (foreign-born women who spent more than 10 years in Portugal). Logistic regression model was fitted to estimate the association between the aforementioned migration statuses and having or not smoked tobacco during pregnancy, taking into account women’s age, parity, marital status, level of education, family income, country of origin of women’s parents and gestational age at the first prenatal care visit. Adjusted odds-ratio (OR) and respective 95% confidence interval (95%CI) were obtained.
RESULTS: A little over half of the study participants were foreign-born and almost 60% of those were recent migrants. Tobacco smoking during pregnancy was evidently more prevalent among native women than among long-term or recent migrant women (14% vs. 8% and 4% respectively; p<0.001). Compared to native women, both long-term and recent migrant women were more likely to be unmarried, have a family income lower than 1000€, and have their first prenatal visit after 12 weeks of gestation. Long-term migrants were more likely to have Portuguese-born parents than recent migrants (26.0% vs. 2.5%; p<0.001).
According to the multivariate regression model, having a higher educational level was significantly associated with not smoking during pregnancy (secondary school: OR=0.38; 95%CI:0.23–0.62; postgraduate education: OR=0.18; 95%CI:0.09–0.35), opposed to women who have 9 or less years of education. However no association was observed between smoking during pregnancy and maternal age (OR=1.10; 95%CI:0.60–2.01 and OR=0.95; 95%CI:0.57–1.58 for women aged less than 25 and 35 or more years, respectively, in comparison with women aged 25-34 years), family income (OR=1.30; 95%CI:0.77–2.18 for women with higher income), parity (OR=0.68; 95%CI:0.43–1.09 for multiparous in comparison with primiparous women), gestational age at first prenatal visit (OR=1.12, 95%CI:0.59–2.11 for women having their first prenatal visit after 12 weeks), having a foreign-born parent (yes vs no: OR=0.83; 95%CI:0.43–1.63) and marital status (single vs married women: OR=0.76; 95%CI:0.46–1.24). Smoking during pregnancy was significantly less frequent in recent and long-term migrants (OR=0.24; 95%CI:0.10-0.57, OR=0.52, 95%CI: 0.25-1.09 respectively) compared with native Portuguese women.
CONCLUSION: Results of this study demonstrated significant disparities in the prevalence of maternal smoking during pregnancy according to the women’s place of birth and duration of stay in Portugal. Native-born women had a higher risk of smoking during pregnancy than foreign-born women. The increase in the duration of stay in the host country seemed to have a negative effect on maternal smoking of migrants in Portugal. Smoking cessation health strategies in pregnant women in Portugal need to be improved by taking into account the mentioned variations in smoking behaviors.info:eu-repo/semantics/publishedVersio
Deposition of stainless steel thin films: an electron beam physical vapour deposition approach
This study demonstrates an electron beam physical vapour deposition approach as an alternative stainless steel thin films fabrication method with controlled layer thickness and uniform particles distribution capability. The films were fabricated at a range of starting electron beam power percentages of 3–10%, and thickness of 50–150 nm. Surface topography and wettability analysis of the samples were investigated to observe the changes in surface microstructure and the contact angle behaviour of 20 °C to 60 °C deionised waters, of pH 4, pH 7, and pH 9, with the as-prepared surfaces. The results indicated that films fabricated at low controlled deposition rates provided uniform particles distribution and had the closest elemental percentages to stainless steel 316L and that increasing the deposition thickness caused the surface roughness to reduce by 38%. Surface wettability behaviour, in general, showed that the surface hydrophobic nature tends to weaken with the increase in temperature of the three examined fluids
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