Graphene setting the stage: tracking DNA hybridization with nanoscale resolution

In this study we use nanophotonic effects of graphene to study DNA hybridization: the z−4 nanoscale distance-dependence of the fluorescence lifetime for fluorophores located in the vicinity of graphene is for the first time used to track a DNA hybridization reaction with nanoscale resolution in real time. First, a nanostaircase with ≈2 nm steps from 0 to a total height of 48 nm is used as a nanoruler to confirm the distance dependence law. We find that the axial sensitivity is suited to determine the nanoscale surface roughness of these samples. The proof-of-concept DNA experiments in aqueous medium involve the hybridization of fluorescently labelled DNA beacons attached to CVD grown graphene with complementary (target) DNA added in solution. We track the conformational changes of the beacons statistically by determining the fluorescence lifetimes of the labelling dye and converting them into nanoscale distances from the graphene. In this way, we are able to monitor the vertical displacement of the label during DNA-beacon unfolding with an axial resolution reaching down to 1 nm. The measured distance increase during the DNA hybridization reaction of about 10 nm matches the length of the target DNA strand. Furthermore, the width of the fluorescence lifetime distributions could be used to estimate the molecular tilt angle of the hybridized ds-DNA configuration. The achieved nanoscale sensitivity opens innovation opportunities in material engineering, genetics, biochemistry and medicine.INL received support for this project from the CCDR-N via the project 'Nanotechnology based functional solutions' (Grant No. NORTE-01-0145-FEDER-000019) and from the Portuguese Foundation for Science and Technology (FCT) via the project 'ON4SupremeSens' PTDC/NAN-OPT/29417/2017. Edite Figueiras received a Marie Curie fellowship via the EU-EC COFUND program 'NanoTRAINforGrowth' (Grant No. 600375). U Minho research was partially supported by the FCT in the framework of the Strategic Funding UID/FIS/04650/2013

Biological protein precipitation: a green process for the extraction of cucumisin from melon (Cucumis melo L. inodorus) by-products

Cucumisin (CUC) from industrial melon by-products was separated for the first time through biological precipitation using carrageenan (CRG). This approach could represent a cost-effective and environmentally friendly process for the industries, avoiding the use of expensive equipment and toxic salts or solvents, such as butanol and ethanol. In this study, biological precipitation of proteins from melon by-products using CRG was studied and compared with conventional precipitation with ammonium sulphate. Different methods were applied for the identification and characterization of isolated proteins, including SDS-PAGE gel, FPLC and proteolytic activity assays. The isolated CUC confirmed a molecular weight of 68 kDa and showed highly stable proteolytic (PA) and milk-clotting (MCA) activities in a wide range of CaCl2 (20 to 60 mM), pH (5 to 7) and temperatures (30 to 85 ºC). Melon peel extract demonstrated to possess significant PA (4.24 U/mg protein) and MCA (191.50 MCU/mg protein), but such values were increased by ammonium sulphate precipitation (1.60 and 2.06-folds, respectively), and specially a noticeable increment was observed by biological precipitation with 2.11 and 17.65-folds, respectively, demonstrating the capability to be an effective strategy to isolate and purify CUC, allowing a yield of 0.17 g CUC/100 g of by-products and keeping its biological properties.info:eu-repo/semantics/publishedVersio

Examination of the Feynman-Hibbs Approach in the Study of NeN_N-Coronene Clusters at Low Temperatures

Feynman-Hibbs (FH) effective potentials constitute an appealing approach for investigations of many-body systems at thermal equilibrium since they allow us to easily include quantum corrections within standard classical simulations. In this work we apply the FH formulation to the study of Ne$_N$-coronene clusters ($N=$ 1-4, 14) in the 2-14 K temperature range. Quadratic (FH2) and quartic (FH4) contributions to the effective potentials are built upon Ne-Ne and Ne-coronene analytical potentials. In particular, a new corrected expression for the FH4 effective potential is reported. FH2 and FH4 cluster energies and structures -obtained from energy optimization through a basin-hoping algorithm as well as classical Monte Carlo simulations- are reported and compared with reference path integral Monte Carlo calculations. For temperatures $T> 4$ K, both FH2 and FH4 potentials are able to correct the purely classical calculations in a consistent way. However, the FH approach fails at lower temperatures, especially the quartic correction. It is thus crucial to assess the range of applicability of this formulation and, in particular, to apply the FH4 potentials with great caution. A simple model of $N$ isotropic harmonic oscillators allows us to propose a means of estimating the cut-off temperature for the validity of the method, which is found to increase with the number of atoms adsorbed on the coronene molecule

Morphological evaluation of fetal membranes and placenta of wild life Mazama gouazoubira deer in the first third of pregnancy

Mazama gouazoubira, o veado-catingueiro, é uma espécie de cervídeo de porte pequeno, que pode ser encontrado na América do Sul, desde o sul do Uruguai até o norte de Mato Grosso, no Brasil. Este estudo teve como objetivo descrever as membranas fetais e a placenta de M. gouazoubira no terço inicial de gestação. As amostras coletadas foram analisadas macroscopicamente e microscopicamente. O exame do útero demonstrou uma gestação univitelina e um embrião com crown-rump de 13mm. Na análise do embrião pode ser observado o olho pigmentado, as saliências auriculares, o mesonefro e e metanefro em desenvolvimento, o fígado e sua proeminência externa, o estômago, os membros torácicos e os brotos dos membros pélvicos. A placenta apresentou-se oligocotiledonária e no útero puderam ser observadas nove carúnculas. O saco gestacional mediu 15cm de comprimento e, como observado no início da gestação dos ruminantes domésticos, os cotilédones não puderam ser identificados macroscopicamente. Uma fraca adesão foi observada entre as carúnculas e a membrana corioalantóica (cotilédones) que formavam os placentônios. A membrana corioalantóica demonstrou um alantóide bem vascularizado composto por uma fina camada de células de núcleos e citoplasmas alongados. Na outra face da membrana, o cório foi composto por células cúbicas, de citoplasmas escassos e núcleos grandes e arredondados, características de células trofoblásticas. Envolvendo o embrião visualizou-se o saco amniótico constituído de duas camadas passíveis de separação mecânica, que apresentaram morfologia similar, sendo formadas por um epitélio pavimentoso avascular. Não foi observado saco vitelino no estágio gestacional do espécime estudado. Conclui-se que a placenta de M. gouazoubira é oligocotiledonária, como observado em outros cervídeos, e que as membranas fetais apresentam semelhanças com a de outros ruminantes, incluindo as características citológicas. Estudos adicionais são necessários para determinar a presença do saco vitelino e quando ocorre sua regressão.Mazama gouazoubira is a small-sized deer, which can be found in South America, from southern Uruguay to the north of Mato Grosso, Brazil. This study aimed to describe the fetal membranes and placenta of M. gouazoubira in the first third of pregnancy. Samples collected were macroscopically and microscopically analyzed. Uterus examination demonstrated univitelinic gestation with an embryo measuring a crown-rump length of 13mm. In the embryo analysis we could identify the pigmented eye, auricular hillocks, mesonephron and early metanephron, liver and its external prominence, stomach, thoracic members and buds of pelvic members. Placenta was oligocotyledonary and nine caruncles were found in the uterus. Gestational sac measured 15cm in length, and, as observed in the early gestation of domestic ruminants, cotyledons could not be identified macroscopically. A weak adhesion was found between caruncles and chorioallantoic membrane (cotyledons) forming the placentomes. The chorioallantoic membrane showed a well-vascularized allantoid composed by a thin layer of cells with stretched nucleus and cytoplasm. On the other side of the membrane, the chorion was composed by cubic cells with scant cytoplasm and large-rounded nuclei, features of trophoblast cells. Involving the embryo we identified a two-layered amniotic sac. Layers could be mechanically separated and had similar morphology, showing a non-vascularized squamous epithelium. There was no yolk sac in the gestational stage of this specimen. We concluded that the placenta of M. gouazoubira is an oligocotyledonary placenta, as observed in others cervids, and that the fetal membranes showed similarities with those from other domestic ruminants, including cytological characteristics. Further studies are required in order to determine the presence of the yolk sac and its regression time

Impact of simulated in vitro gastrointestinal digestion on bioactive compounds, bioactivity and cytotoxicity of melon (Cucumis melo L. inodorus) peel juice powder

The objectives of this research work were to evaluate the effect of in vitro gastrointestinal digestion (GIT) on melon peel juice (MPJ) powder from fruit processing industry by-products, considering (i) the recovery and accessibility indexes, (ii) the changes on antioxidant activity, and (iii) the prebiotic effect. Throughout exposition to GIT conditions a decrease on the total phenolic content (TPC = 65.31%) and antioxidant activity by ABTS = 39.77% and DPPH = 45.91% were observed. However, these both parameters exhibited stable accessibility, accounting with 81.89%, 76.55%, and 54.07% for TPC, ABTS and DPPH, respectively. After gastrointestinal digestion, the non-absorbed fraction exhibited a positive impact on the growth of Bifidobacterium and Lactobacillus strains, possibly associated with the high content of simple sugar (glucose and fructose). This fraction also showed to be safe on Caco-2 intestinal cells. These findings suggest that MPJ might be used as a potential food functional ingredient.info:eu-repo/semantics/publishedVersio

Left ventricular systolic dysfunction in Marfan syndrome is related to aortic distensibility

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2019.Background: The cardiovascular involvement in Marfan syndrome (MS) is characterized mainly by dilatation and reduced distensibility of the ascending aorta. Left ventricular (LV) dysfunction has been detected in MS and a primary cardiomyopathy has been suggested but the pathophysiology is unclear. The purpose of this study was to evaluate the LV function in patients with MS and to assess the relationship with the aortic distensibility, as possible underlying mechanism. Methods: We studied 53 patients with MS (27.0 ± 11 years, 29 men) without valvular or hypertensive heart disease and a control group of 26 healthy subjects (29 ± 9 years, 17 men). All underwent echocardiography and cardiac magnetic resonance (CMR) and the following indexes were analyzed: a) Echo: mitral flow velocities E/A ratio and deceleration of mitral E; E’ velocity obtained from the medial and lateral mitral ring; E/E’ ratio b) CMR: LV volumes indexed to BSA and ejection fraction (EF); global longitudinal strain (GLS, Circle cvI42); maximal size and distensibility of proximal ascending aorta. Distensibility was calculated from maximal (systolic) and minimum (diastolic) area of maximal proximal ascending aorta (cross-sectional images from SSFP sequence) using the formula=(maximum area-minimum area)/[ minimum area x (systolic BP-diastolic BP)]. Results: 17 from 53 patients with MS had increased LV end-diastolic volume, 14 decreased EF (<50%) and 22 decreased GLS. Compared with the control group, patients with MS showed increased LV end-diastolic volume (85.0 ± 5.2vs 80.1 ± 5.3ml/m2, p = 0.04), lower GLS (17.1 ± 1.9 vs 18.9 ± 2.2, p = 0.01) lower LVEF (53.0 ± 7.1% vs 56.0 ± 5.4%, p = 0.03) and higher E/E’ value (9.2 ± 1.3 vs. 6.2 ± 0.8, p = 0.01) as well as larger dimensions of proximal aorta (39 ± 2.2cm vs 32 ± 0.8,p = 0.010) and lower aortic distensibility (3.4 ± 1.9 vs. 4.4 ± 1.7 dynes cm-1, p = 0.03). In the group of patients, a correlation was found between the aortic distensibility and the LVEF (r = 0.47, p = 0.045) and GLS (r = 0.65, p = 0.02), but not with the other variables. Aortic distensibility was an independent predictor of LV dysfunction using a cutoff of 50% for LVEF and 19% for GLS. Conclusion: In our population of patients with MS, we found changes in the LV function, which were related with aortic distensibility, possibly sharing a common pathway. The prognostic significance of these findings is under evaluation.info:eu-repo/semantics/publishedVersio

Global conservation prioritization areas in three dimensions of crocodilian diversity

Crocodilians are a taxonomic group of large predators with important ecological and evolutionary benefits for ecosystem functioning in the face of global change. Anthropogenic actions affect negatively crocodilians' survival and more than half of the species are threatened with extinction worldwide. Here, we map and explore three dimensions of crocodilian diversity on a global scale. To highlight the ecological importance of crocodilians, we correlate the spatial distribution of species with the ecosystem services of nutrient retention in the world. We calculate the effectiveness of global protected networks in safeguarding crocodilian species and provide three prioritization models for conservation planning. Our results show the main hotspots of ecological and evolutionary values are in southern North, Central and South America, west-central Africa, northeastern India, and southeastern Asia. African species have the highest correlation to nutrient retention patterns. Twenty-five percent of the world's crocodilian species are not significantly represented in the existing protected area networks. The most alarming cases are reported in northeastern India, eastern China, and west-central Africa, which include threatened species with low or non-significant representation in the protected area networks. Our highest conservation prioritization model targets southern North America, east-central Central America, northern South America, west-central Africa, northeastern India, eastern China, southern Laos, Cambodia, and some points in southeastern Asia. Our research provides a global prioritization scheme to protect multiple dimensions of crocodilian diversity for achieving effective conservation outcomes

Risk of development of diabetes Mellitus in higher education students and their correlation with weight and BMI

Introdução: Estudos recentes indicam que a prevalência de diabetes mellitus tem aumentado de forma alarmante a nível mundial, e que em 2040, um em cada 10 indivíduos será portador desta doença. Objetivos: 1) Avaliar o risco de desenvolver diabetes mellitus nos próximos 10 anos, em estudantes do Ensino Superior; 2) Correlacionar peso e IMCcom o risco de desenvolver diabetes mellitus. Material e Métodos: Participaram no estudo 356 estudantes do Ensino Superior (M±DP=21,10±3,69 anos de idade), tendo os dados sido recolhidos mediante a aplicação do“Questionário de Avaliação de Risco de Desenvolver Diabetes nos Próximos 10 Anos”, desenvolvido pelo Centro Hospitalar e Universitário de Coimbra (CHUC). Para correlação do peso e IMC utilizou-se a correlação de Spearman. Resultados: A maioria dos participantes (n=326; 91,6%) apresenta baixo risco de desenvolvimento de diabetes mellitus e existe uma correlação positiva e significativa entre risco de desenvolvimento de diabetes mellitus e peso (p= 0,001; r=0,179; correlação pequena) e IMC (p= 0,001; r=0,251;correlação pequena). Conclusões: Os achados confirmam a importância da atividade física desportiva e alimentação saudável para a redução/controlo do peso corporal, diminuindo assim o risco de prevalência da doença.info:eu-repo/semantics/publishedVersio

Usefulness of discriminability and response bias indices for the evaluation of recognition memory in mild cognitive impairment and Alzheimer disease

Background: Most studies examining episodic memory in Alzheimer disease (AD) have focused on patients' impaired ability to remember information. This approach provides only a partial picture of memory deficits since other factors involved are not considered. Objective: To evaluate the recognition memory performance by using a yes/no procedure to examine the effect of discriminability and response bias measures in amnestic mild cognitive impairment (a-MCI), AD dementia, and normal-aging subjects. Methods: We included 43 controls and 45 a-MCI and 51 mild AD dementia patients. Based on the proportions of correct responses (hits) and false alarms from the Rey Auditory Verbal Learning Test (RAVLT), discriminability (d′) and response bias (C) indices from signal detection theory (SDT) were calculated. Results: Results showed significant group differences for d′ (F (2) = 83.26, p < 0.001), and C (F (2) = 6.05, p = 0.00). The best predictors of group membership were delayed recall and d′ scores. The d′ measure correctly classified subjects with 82.98% sensitivity and 91.11% specificity. Conclusions: a-MCI and AD dementia subjects exhibit less discrimination accuracy and more liberal response bias than controls. Furthermore, combined indices of delayed recall and discriminability from the RAVLT are effective in defining early AD. SDT may help enhance diagnostic specificity