Double power law behavior in everyday phenomena

We study similar statistical properties observed in distinct real world data. In particular, we focus on the power law (PL) distribution. We nd that some data is well tted by a single PL distribution whereas other phenomena force the use of two distinct PLs. This behavior is similar in, a priori, unrelated phenomena, such as catastrophes (terrorism, earthquakes) and variables associated to man-made systems, such as distribution of the number of words in texts or of the number of hits received by websites.N/

Mutual diffusivity in n-Heptane + n-Hexane isomers

A preliminary study of the effect of branching in the binary diffusion of hexane isomer + n-heptane systems is presented. Measurements have been performed with an instrument modeled for the Taylor dispersion technique, at several compositions, at 297 K, for the n-hexane + n-heptane and 2,2-dimethylbutane + n-heptane binary mixtures. The accuracy is estimated to be 1%. The influence of branching is discussed. It was found that the rough hard sphere model for binary diffusion can reproduce the experimental data within 6%. This model was used to predict the binary diffusion coefficients in the 2-methylpentane + n-heptane and 3-methylpentane + n-heptane mixtures, with an estimated accuracy of 5%

Self-similarity in world economy

Self-similarity is a property of complex networks, commonly observed in many distinct areas of science. Many real networks are said to be ¸ Sscale-freeˇT since they show a power law behavior. In this paper, we focus in self-similarity of economical phenomena. For that purpose we analyze data and their corresponding statistical properties. We approximate data by trendlines, whose parameters are unequivocally related with each type of phenomenon.N/

Pareto and Zipf laws for city size distribution

Pareto and Zipf distributions have been used in the modeling of distinct phenomena, namely in biology, demography, computer science, economics, amongst others. In this paper, it is presented a short review of applications of these distributions in city sizes.N/

Gellan gum-based hydrogels support the recreation of the dermal papilla microenvironment

The dermal papilla (DP), a specialized compartment within the hair follicle, regulates hair growth. However, human DP cells rapidly lose their inductivity in 2D-culture given the loss of positional and microenvironmental cues. Spheroids have been capable of recreating the 3D intercellular organization of DP cells, however, DP cell-matrix interactions are poorly represented. Considering the specific nature of the DP's extracellular matrix (ECM), we functionalized gellan gum (GG) with collagen IV-(HepIII) or fibronectin-(cRGDfC) derived peptide sequences to generate a 3D environment in which the phenotype and physiological functions of DP cells are restored. We further tuned the stiffness of the microenvironments by varying GG amount. Biomimetic peptides in stiffer hydrogels promoted the adhesion of DP cells, while each peptide and amount of polymer independently influenced the type and quantity of ECM proteins deposited. Furthermore, although peptides did not seem to have an influence, stiffer hydrogels improved the inductive capacity of DP cells after short term culture. Interestingly, independently of the peptide, these hydrogels supported the recapitulation of basic hair morphogenesis-like events when incorporated in an organotypic human skin in vitro model. Our work demonstrates that tailored GG hydrogels support the generation of a microenvironment in which both cell-ECM and cell-cell interactions positively influence DP cells towards the creation of an artificial DP.Authors would like to acknowledge the financial support from the Consolidator Grant “ECM_INK” (ERC-2016-COG-726061) and from FCT/MCTES (Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior) through the PD/59/2013, PD/BD/113800/2015 (Carla Abreu), PD/169/2013 (Manuela Lago) and IF/00945/2014 (Alexandra Marques) grants. The authors also appreciate the support given by the FSE/POCH (Fundo Social Europeu through the Programa Operacional do Capital Humano) under the scope of the NORTE-08-5369-FSE-000037 grant (Manuela Lago)

Click chemistry oligomerisation of azido-alkyne-functionalised galactose accesses triazole-linked linear oligomers and macrocycles that inhibit Trypanosoma cruzi macrophage invasion

AbstractReaction of 2-(2-(2-azidoethoxy)ethoxy)ethyl 6-O-(prop-2-ynyl)-β-d-galactopyranoside (7) under CuAAC conditions gives rise to mixed cyclic and linear triazole-linked oligomers, with individual compounds up to d.p. 5 isolable, along with mixed larger oligomers. The linear compounds resolve en bloc from the cyclic materials by RP HPLC, but are separable by gel permeation chromatography. The triazole-linked oligomers—pseudo-galactooligomers—were demonstrated to be acceptor substrates for the multi-copy cell surface trans-sialidase of the human parasite Trypanosoma cruzi. In addition, these multivalent TcTS ligands were able to block macrophage invasion by T. cruzi

β-amino alcohols and their respective 2-phenyl-N-alkyl aziridines as potential DNA minor groove binders

It is known that aziridines and nitrogen mustards exert their biological activities, especially in chemotherapy, via DNA alkylation. The studied scaffold, 2-phenyl-1-aziridine, provides a distinct conformation compared to commonly used aziridines, and therefore, leads to a change in high-strained ring reactivity towards biological nucleophiles, such as DNA. The above series of compounds was tested in three breast cell lines: MCF-10, a healthy cell; MCF-7, a hormone responsive cancer cell; and MDA-MB-231, a triple negative breast cancer cell. Both aziridines and their precursors, β-amino alcohols, showed activity towards these cells, and some of the compounds showed higher selectivity index than cisplatin, the drug used as control. When the type of cell death was investigated, the synthesized compounds demonstrated higher apoptosis and lower necrosis rates than cisplatin, and when the mechanism of action was studied, the compounds were shown to interact with DNA via its minor groove instead of alkylation or intercalation

Standardised sampling of lepidopterans (Lepidoptera) in Serra da Estrela (Portugal) - 2013 and 2014. v1.2

Mountain ecosystems are crucial for biodiversity conservation since they host high biodiversity. This study reports novel information on lepidopteran species diversity, distribution and abundance from Serra da Estrela Natural Park (Portugal). Seventy two lepidopteran species were sampled in this protected area, including the first findings of Apatura ilia (Denis & Schiffermüller, 1775) and Vanessa virginiensis (Drury, 1773). New populations of Euphydrias aurinia (Rottemburg, 1775), a protected species under the Habitats Directive, was found in this Natural Park and novel distribution and ecological data was collected for most species, including several rare species [e.g., Coenonympha glycerion iphioides Staudinger, 1870, Cyaniris semiargus (Rottemburg, 1775)]. All data were collected using standardised sampling allowing its use as baseline for environmental changes long-term monitoring of Serra da Estrela mountain biodiversity.FUNDING: The study was financed by Energias de Portugal (EDP) under the Fundo EDP para a Biodioversidade 2011.info:eu-repo/semantics/publishedVersio

Standardised sampling of odonates (Odonata) in Serra da Estrela (Portugal) - 2013 and 2014

Mountain ecosystems are crucial for biodiversity conservation since they host high biodiversity. This study reports novel information on odonate species diversity, distribution and abundance from Serra da Estrela Natural Park (Portugal). Twenty six odonate species were sampled in this protected area, including the first finding of Macromia splendens (Pictet, 1843). New populations of Oxygastra curtisii (Dale, 1834), a protected species under the Habitats Directive, was found in this Natural Park and novel distribution and ecological data was collected for most species, including several rare species (e.g., Aeshna juncea (Linnaeus, 1758), Sympetrum flaveolum (Linnaeus, 1758)). All data were collected using standardised sampling allowing its use as baseline for long-term monitoring of Serra da Estrela mountain biodiversity.FUNDING: This work was financed by Energias de Portugal (EDP) Fund for Biodiversity 2011 through project "Biodiversidade, endemismos e espécies protegidas associadas às lagoas e cursos de água da Serra da Estrela: valorização de um século de aproveitamento hidroeléctrico". Fundação para a Ciência e a Tecnologia supported MB by contract DL 57/2016/CP1375/CT0001.info:eu-repo/semantics/publishedVersio