A Metrological Based Realization of Time-of-Flight Diffraction Technique

AbstractTime-of-Flight Diffraction (ToFD) is a technique of non-destructive testing by ultrasound used for detecting faults and discontinuities in different components. The development and implementation of this technique was based on ISO 16828:2012 (Non-Destructive testing – Ultrasonic Testing – Time-of-Flight Diffraction Technique as a method for Detection and Sizing of Discontinuities). Controlling the different characteristics of the system, from the specification of the ultrasonic characteristics, to the imaging technique, was possible to identify the sources of uncertainty and estimate the ToFD measurement uncertainty. For a 25mm deep stainless steel test object, expanded uncertainties less than 0.5%(0.093 mm) was achieved with ToFD. For larger ultrasonic paths, the technique is able to depict even lower uncertainties, regarding some care are taken in the ultrasonic measurement setup

A Transcriptomic Approach to the Recruitment of Venom Proteins in a Marine Annelid

CEECIND/02699/2017The growing number of known venomous marine invertebrates indicates that chemical warfare plays an important role in adapting to diversified ecological niches, even though it remains unclear how toxins fit into the evolutionary history of these animals. Our case study, the Polychaeta Eulalia sp., is an intertidal predator that secretes toxins. Whole-transcriptome sequencing revealed proteinaceous toxins secreted by cells in the proboscis and delivered by mucus. Toxins and accompanying enzymes promote permeabilization, coagulation impairment and the blocking of the neuromuscular activity of prey upon which the worm feeds by sucking pieces of live flesh. The main neurotoxins ("phyllotoxins") were found to be cysteine-rich proteins, a class of substances ubiquitous among venomous animals. Some toxins were phylogenetically related to Polychaeta, Mollusca or more ancient groups, such as Cnidaria. Some toxins may have evolved from non-toxin homologs that were recruited without the reduction in molecular mass and increased specificity of other invertebrate toxins. By analyzing the phylogeny of toxin mixtures, we show that Polychaeta is uniquely positioned in the evolution of animal venoms. Indeed, the phylogenetic models of mixed or individual toxins do not follow the expected eumetazoan tree-of-life and highlight that the recruitment of gene products for a role in venom systems is complex.publishersversionpublishe

Ultrasound Methods for Biodiesel Production and Analysis

Ultrasonic techniques have been widely used in biodiesel production, since the acoustic cavitation is a phenomenon capable of accelerating potentially the transesterification reactions. The equipment employed in such approach was simply equipment available in any regular laboratory of chemistry. Further developments introduced the ultrasound as an important tool to produce biodiesel. The main advantage is increasing the conversion of esters at reduced reaction times, with significantly lower production costs. As a method for characterization and analysis of materials, ultrasound has been used since several decades ago. However, ultrasonic analytical methods based on metrological principles are fairly recent investigated. Using ultrasound as physical principle to interrogate biodiesel is a promising field of research, with some remarkable outcomes produced so far. The aim of this chapter is to demonstrate advances of using ultrasonic techniques in production and characterization of biodiesel, as well as an appraisal of the current technology status, and provide insights into future developments

Ultrasound as a Metrological Tool for Monitoring Transesterification Kinetics

Ultrasound has been widely used as a technological alternative way to analyse non-invasively an assortment of materials. It includes liquids with dissimilar physical characteristics, including mono- and multi-phasic mixtures, suspension formation and dissolution, in-line processing, among other practical applications. Regardless the huge spread of uses, so far ultrasound has not been proved to be able to quantify transesterification kinetics with a metrological approach. The aim of this chapter is to demonstrate that a properly designed ultrasonic experiment can be developed to identify remarkable stages of a transesterification reaction to produce biodiesel. The method was compared both with gas chromatography and hydrogen nuclear magnetic resonance (1H NMR). For an in-line application, ultrasound has been proved to work properly as a monitoring tool for chemical reaction kinetics

Specific Antiproliferative Properties of Proteinaceous Toxin Secretions from the Marine Annelid Eulalia sp. onto Ovarian Cancer Cells

The Portuguese Foundation for Science and Technology (FCT) funded project WormALL (PTDC/BTA-BTA/28650/2017) plus the grants SFRH/BD/109462/2015 to A.P.R., and CEECIND/02699/2017 to A.R.G. The Applied Molecular Biosciences Unit-UCIBIO is financed by national funds from FCT, ref. UIDB/04378/2020. FCT, along with the European Regional Development Fund (ERDF) through the COMPETE 2020-Operational Programme for Competitiveness and Internationalisation also funded the projects: POCI-01-0145-FEDER-007440 (UID/NEU/04539/2019), POCI-01-0145-FEDER-016428 (SAICTPAC/0010/2015), POCI-01-0145-FEDER-029311 (PTDC/BTM-TEC/29311/2017), POCI-01-0145-FEDER-30943 (PTDC/MEC-PSQ/30943/2017) and PTDC/MED-NEU/27946/2017. The work was also funded by the National Mass Spectrometry Network (RNEM) under the contract POCI-01-0145-FEDER-402-022125 (ref.: ROTEIRO/0028/2013).As Yondelis joins the ranks of approved anti-cancer drugs, the benefit from exploring the oceans' biodiversity becomes clear. From marine toxins, relevant bioproducts can be obtained due to their potential to interfere with specific pathways. We explored the cytotoxicity of toxin-bearing secretions of the polychaete Eulalia onto a battery of normal and cancer human cell lines and discovered that the cocktail of proteins is more toxic towards an ovarian cancer cell line (A2780). The secretions' main proteins were identified by proteomics and transcriptomics: 14-3-3 protein, Hsp70, Rab3, Arylsulfatase B and serine protease, the latter two being known toxins. This mixture of toxins induces cell-cycle arrest at G2/M phase after 3h exposure in A2780 cells and extrinsic programmed cell death. These findings indicate that partial re-activation of the G2/M checkpoint, which is inactivated in many cancer cells, can be partly reversed by the toxic mixture. Protein-protein interaction networks partake in two cytotoxic effects: cell-cycle arrest with a link to RAB3C and RAF1; and lytic activity of arylsulfatases. The discovery of both mechanisms indicates that venomous mixtures may affect proliferating cells in a specific manner, highlighting the cocktails' potential in the fine-tuning of anti-cancer therapeutics targeting cell cycle and protein homeostasis.publishersversionpublishe

Um dashboard para a percepção dos professores sobre as atividades de estudantes em ambiente virtual de aprendizagem

Este estudo apresenta o desenvolvimento de um dashboard para ser incorporado a um ambiente virtual de aprendizagem. O dashboard permite aos professores um maior acompanhamento das atividades dos estudantes no ambiente. As diretrizes da pesquisa foram definidas a partir da análise de três outras propostas similares, sendo o método Design Science Research escolhido para o percurso metodológico. Os resultados apontam que o dashboard obteve bons indicadores, tanto para questões de usabilidade quanto para aceitação do artefato proposto

Deciphering Network Community Structure by Surprise

The analysis of complex networks permeates all sciences, from biology to sociology. A fundamental, unsolved problem is how to characterize the community structure of a network. Here, using both standard and novel benchmarks, we show that maximization of a simple global parameter, which we call Surprise (S), leads to a very efficient characterization of the community structure of complex synthetic networks. Particularly, S qualitatively outperforms the most commonly used criterion to define communities, Newman and Girvan's modularity (Q). Applying S maximization to real networks often provides natural, well-supported partitions, but also sometimes counterintuitive solutions that expose the limitations of our previous knowledge. These results indicate that it is possible to define an effective global criterion for community structure and open new routes for the understanding of complex networks.Comment: 7 pages, 5 figure

Quantum Conductance in Semimetallic Bismuth Nanocontacts

Electronic transport properties of bismuth nanocontacts are analyzed by means of a low temperature scanning tunneling microscope. The subquantum steps observed in the conductance versus elongation curves give evidence of atomic rearrangements in the contact. The underlying quantum nature of the conductance reveals itself through peaks in the conductance histograms. The shape of the conductance curves at 77 K is well described by a simple gliding mechanism for the contact evolution during elongation. The strikingly different behaviour at 4 K suggests a charge carrier transition from light to heavy ones as the contact cross section becomes sufficiently small.Comment: 5 pages including 4 figures. Accepted for publication in Phys. Rev. Let

The Deubiquitinating Enzyme Ataxin-3 Regulates Ciliogenesis and Phagocytosis in the Retina

Expansion of a CAG repeat in ATXN3 causes the dominant polyglutamine disease spinocerebellar ataxia type 3 (SCA3), yet the physiological role of ATXN3 remains unclear. Here, we focus on unveiling the function of Ataxin-3 (ATXN3) in the retina, a neurological organ amenable to morphological and physiological studies. Depletion of Atxn3 in zebrafish and mice causes morphological and functional retinal alterations and, more precisely, photoreceptor cilium and outer segment elongation, cone opsin mislocalization, and cone hyperexcitation. ATXN3 localizes at the basal body and axoneme of the cilium, supporting its role in regulating ciliary length. Abrogation of Atxn3 expression causes decreased levels of the regulatory protein KEAP1 in the retina and delayed phagosome maturation in the retinal pigment epithelium. We propose that ATXN3 regulates two relevant biological processes in the retina, namely, ciliogenesis and phagocytosis, by modulating microtubule polymerization and microtubule-dependent retrograde transport, thus positing ATXN3 as a causative or modifier gene in retinal/macular dystrophies