bluuebunny/crossref_metadata_2025 huggingface dataset:
Inline holographic microscopy through fiber imaging bundles
Authors: Hughes Michael R.
Published: September 2020

Fiber imaging bundles are widely used as thin, passive image conduits for miniaturized and endoscopic microscopy, particularly for confocal fluorescence imaging. Holographic microscopy through fiber bundles is more challenging; phase conjugation approaches are complex and require extensive calibration. This paper describes how simple inline holographic microscopy can be performed through an imaging bundle using a partially coherent illumination source from a multimode fiber. The sample is imaged in transmission, with the intensity hologram sampled by the bundle and transmitted to a remote camera. The hologram can then be numerically refocused for volumetric imaging, achieving a resolution of approximately 6 µm over a depth range of 1 mm. The scheme does not require any complex prior calibration and hence is insensitive to bending.
Spectroscopic detection of traumatic brain injury severity and biochemistry from the retina
Authors: Banbury Carl , Styles Iain , Eisenstein Neil , Zanier Elisa R. , Vegliante Gloria , Belli Antonio , Logan Ann , Goldberg Oppenheimer Pola
Published: September 2020

Traumatic brain injury (TBI) is a major burden on healthcare services worldwide, where scientific and clinical innovation is needed to provide better understanding of biochemical damage to improve both pre-hospital assessment and intensive care monitoring. Here, we present an unconventional concept of using Raman spectroscopy to measure the biochemical response to the retina in an ex-vivo murine model of TBI. Through comparison to spectra from the brain and retina following injury, we elicit subtle spectral changes through the use of multivariate analysis, linked to a decrease in cardiolipin and indicating metabolic disruption. The ability to classify injury severity via spectra of the retina is demonstrated for severe TBI (82.0 %), moderate TBI (75.1 %) and sham groups (69.4 %). By showing that optical spectroscopy can be used to explore the eye as the window to the brain, we lay the groundwork for further exploitation of Raman spectroscopy for indirect, non-invasive assessment of brain chemistry.
Planar Resonators Supporting Extremely Confined Phonon-Polariton Modes
Authors: Dubrovkin Alexander M. , Qiang Bo , Salim Teddy , Nam Donguk , Zheludev Nikolay I. , Wang Qi Jie
Published: September 2020

Infrared nanoimaging revealed extremely subwavelength sheet and edge surface phonon-polariton modes on few-nm thick CMOS-compatible Ge-on-SiC resonators. Surface nature of phononic modes on these ultrathin planar structures enables local sensing at the molecular scale.
Phonon-Polariton-Enhanced Nonlinearity in Hexagonal Boron Nitride
Authors: Jadidi M. Mehdi , Ginsberg Jared S. , Patwardhan Gauri , Chae Sang Hoon , Chen Cecilia Y. , Li Baichang , Watanabe Kenji , Taniguchi Takashi , Hone James , Gaeta Alexander L.
Published: September 2020

We report the first measurements of the nonlinear response of phonon polaritons near 7.3 µm in atomically thin layers of hexagonal boron nitride. We observe the phonon-enhanced third harmonic and the transient phonon-induced second harmonic.
Space-Time Wave Packets as a Platform for a Free-Space Optical Delay Line
Authors: Yessenov Murat , Bhaduri Basanta , Delfyett Peter J. , Abouraddy Ayman F.
Published: September 2020

We demonstrate free-space optical delay lines that make use of diffraction-free space-time wave-packets whose group velocities are continuously tunable in free space, and thus provides a potential platform for all-optical buffers by providing group delays that far exceed the pulse widths.
Experimental Demonstration of Optimal Curved Beams in Micrometer-Scale
Authors: Aborahama Yousuf , Dorrah Ahmed H. , Mojahedi Mo
Published: September 2020

Using ideas from optimization theory and calculus of variation we demonstrate beams that follow curved trajectories in micrometers scale, in air. Unlike commonly studied Airy beams, the beams generated here have minimal side lobes.
Mechanically Mediated Entanglement of Propagating Optical Modes
Authors: Chen Junxin , Rossi Massimiliano , Mason David , Schliesser Albert
Published: September 2020

We demonstrate stationary entanglement between two non-degenerate prop agating optical modes, via interaction with the same soft-clamped mechanical mode. We detect, without any corrections, correlations corresponding to a logarithmic negativity of En = 0.35.
Toward Efficient Microwave-Optical Transduction using Cavity Electro-Optics in Thin-Film Lithium Niobate
Authors: Holzgrafe Jeffrey , Sinclair Neil , Zhu Di , Shams-Ansari Amirhassan , Colangelo Marco , Hu Yaowen , Zhang Mian , Berggren Karl K. , Loncar Marko
Published: September 2020

We describe progress toward high-efficiency transduction between microwave and optical radiation using integrated thin-film superconducting microwave resonators and lithium niobate optical resonators.
Wave-Particle Duality Controlled by Single-Photon Self-Entanglement
Authors: Qian X.-F. , Konthasinghe K. , Manikandan S. K. , Spiecker D. , Vamivakas A.N. , Eberly J.H.
Published: September 2020

We experimentally observe that quantum duality of a single photon is controlled by its self-entanglement through a three-way quantum coherence identity V2 + D2 +C2 = 1. Here V, D, C represent waveness, particleness, and self-entanglement respectively.
Development of a non-amphibious amphibian - an interview with a coquí
Authors: Elinson Richard P.
Published: September 2020

Development without a free-living tadpole is common among Ibero American frogs. The most derived condition is direct development where the tadpole has been eliminated, and the most investigated direct developing frog is Eleutherodactylus coqui. To provide a different point-of-view, an imaginary interview with a coqui is conducted. Opinions are offered on invasive species, developmental features that are surprisingly conserved, and novelty in germ layer specification.
Early and late stages of Developmental Biology in Argentina
Authors: Sánchez Sara S. , Honoré Stella M.
Published: September 2020

The history of science in Argentina is based on the enormous contribution that the great immigration of the 19th and 20th centuries produced in the country. The scientific and philosophical ideas and the role played especially by Italian scientists who arrived in the country produced a great impact on the different disciplines including Development Biology in emerging universities. The University of Tucumán pioneered the study of experimental biology, making important contributions to reproductive biology and to the early development of amphibians. The contribution of the Italian embryologist Armando Pisanó and the Argentinian Francisco D. Barbieri expanded the field to other universities and research centers located in Córdoba, La Plata, Bahía Blanca and Rosario. Given its strategic position, laboratories located in the city of Buenos Aires reached technological advances faster than others. Indeed, these laboratories saw the evolution from experimental biology to developmental genetics, renewing interest in this area. Currently, Developmental Biology brings together young researchers eager to consolidate regional and global collaboration networks that seek to help solve specific problems such as fertility, epigenetics, stem cells and tissue engineering.
A tale of turns and cycles guiding to neural crest migration - an interview with Roberto Mayor
Authors: Concha Miguel L.
Published: September 2020

Roberto Mayor is a prominent Chilean developmental biologist working in the UK and an advocate of the developmental biology discipline in Latin America. Roberto started as a preimplantation mouse developmental biologist during his undergraduate and graduate studies in Chile. Yet, he now uses Xenopus and zebrafish to elucidate the mechanisms that drive the directed collective locomotion of neural crest cells. What life events moulded the research career of Roberto across the years? This article addresses this question and provides a personal perspective on his scientific achievements. The story of Roberto is a mix of turns and cycles that ultimately guided him to the migrating neural crest. Turns that made him shift between model organisms and scientific topics. Cycles that drove him back and forth between Chile and the UK and which have connected his early studies as an undergraduate student with the most recent work of his lab. A big lesson that we can learn from the life of Roberto is that no matter how much you plan your life always serendipity plays a significant role. But you have to be alert and brave to take the opportunities that life offers you.
Six decades of scientific pan-Americanism - an interview with Jorge E. Allende
Authors: Allende Miguel L.
Published: September 2020

Jorge E. Allende is a biochemist trained in the United States of America who has been a professor at the University of Chile since 1961. He has served in many leadership positions in both Chilean and international scientific organizations and academic institutions. He led the International Cell Research Organization, the Latin American Network of Biological Sciences and obtained the Chilean National Science Prize. He belongs to the Chilean Academy of Sciences and is a foreign member of the National Academy of Sciences (USA) and also of the National Academy of Medicine (USA). During his career, besides leading a highly successful research group, he was instrumental in generating an esprit de corps among Latin American scientists of all fields in biology starting in the late 1960’s. He began a longstanding tradition by organizing advanced training courses for young scientists from the region who would not have otherwise had the opportunity to experience the latest methods and concepts in biological research, courses that had world leading researchers as instructors. A constant focus of his efforts consisted in promoting the establishment of postgraduate programs in biology throughout the continent, coordinating international funding programs aimed at scientific development in the third world and, more recently, advocating for science education among children and school teachers as the only way to achieve scientific literacy in our societies. In this interview, we explore how these issues were addressed by him and his counterparts in other Latin American countries, at a time when they had to start, essentially, from scratch.
Stress and sex determination in fish: from brain to gonads
Authors: Castañeda-Cortés Diana C. , Fernandino Juan I.
Published: September 2020

Fish present remarkable malleability regarding gonadal sex fate. This phenotypic plasticity enables an organism to adapt to changes in the environment by responding with different phenotypes. The gonad and the brain present this extraordinary plasticity. These organs are involved in the response to environmental stressors to direct gonadal fate, inducing sex change or sex reversal in hermaphroditic and gonochoristic fish, respectively. The presence of such molecular and endocrine plasticity gives this group a large repertoire of possibilities against a continuously changing environment, resulting in the highest radiation of reproduction strategies described in vertebrates. In this review, we provide a broad and comparative view of tremendous radiation of sex determination mechanisms to direct gonadal fate. New results have established that the driving mechanism involves early response to environmental stressors by the brain plus high plasticity of gonadal differentiation and androgens as by-products of stress inactivation. In addition to the stress axis, two other major axes – the hypothalamic-pituitary-gonadal axis and the hypothalamic-pituitary-thyroid axis, which are well known for their participation in the regulation of reproduction – have been proposed to reinforce brain-gonadal interrelationships in the fate of the gonad.
Conserved roles of Rax/rx3 genes in hypothalamus and pituitary development
Authors: De Souza Flávio S. J. , Placzek Marysia
Published: September 2020

Rax (Rx) genes encode paired-type homeodomain-containing transcription factors present in virtually all metazoan groups. In vertebrates, studies in fish, amphibian, chick and mouse models have revealed that these genes play important roles in the development of structures located at the anterior portion of the central nervous system, in particular the eyes, the hypothalamus and the pituitary gland. In addition, human patients with eye and brain defects carry mutations in the two human Rax paralogues, RAX and RAX2. Here, we review work done in the last years on Rax genes, focusing especially on the function that mouse Rax and its zebrafish homologue, rx3, play in hypothalamic and pituitary development. Work on both of these model organisms indicate that Rax genes are necessary for the patterning, growth and differentiation of the hypothalamus, in particular the ventro-tuberal and dorso-anterior hypothalamus, where they effect their action by controlling expression of the secreted signalling protein, Sonic hedgehog (Shh). In addition, Rax/rx3 mutations disturb the development of the pituitary gland, mimicking phenotypes observed in human subjects carrying mutations in the RAX gene. Thus, along with their crucial role in eye morphogenesis, Rax genes play a conserved role in the development of the hypothalamus and adjacent structures in the vertebrate clade.
Inducing your neighbors to become like you: cell recruitment in developmental patterning and growth
Authors: Muñoz-Nava Luis M. , Flores-Flores Marycruz , Nahmad Marcos
Published: September 2020

Cell differentiation, proliferation, and morphogenesis are generally driven by instructive signals that are sent and interpreted by adjacent tissues, a process known as induction. Cell recruitment is a particular case of induction in which differentiated cells produce a signal that drives adjacent cells to differentiate into the same type as the inducers. Once recruited, these new cells may become inducers to continue the recruitment process, closing a feed-forward loop that propagates the growth of a specific cell-type population. So far, little attention has been given to cell recruitment as a developmental mechanism. Here, we review the components of cell recruitment and discuss its contribution to development in three different examples: the Drosophila wing, the vertebrate inner ear, and the mammalian thyroid gland. Finally, we posit some open questions about the role of cell recruitment in organ patterning and growth.
UNESCO Chair of Developmental Biology: how an initiative that fostered careers in Developmental Biology impacted Brazilian Science
Authors: Abreu Jose G.
Published: September 2020

The UNESCO Chair in Developmental Biology started in 1998, at the Institute of Biomedical Sciences of the Federal University of Rio de Janeiro, in Brazil. This Chair was a Brazilian-French initiative led by Professor Vivaldo Moura Neto and Professor Nicole Le Douarin, one of the most inspiring Developmental Biologists of the 20th and 21st centuries. The UNESCO Chair wanted to stimulate interest in Developmental Biology among Brazilian students and scientists by organizing annual international courses on Evolution and Developmental Biology at an advanced level. At the Federal University of Rio de Janeiro, the UNESCO Chair established an international laboratory for the permanent training of researchers and the development of research programs in Developmental Biology and related areas. Moreover, the program aimed at establishing an international network connecting Brazilian Universities and research centers in Latin America and Europe. The advanced hands-on courses, symposiums, and workshops promoted by this Chair inspired the careers of many young scientists. They generated new lines of research in Developmental Biology using a variety of animal models. This review does not intend to bring up all the historical events that marked the beginning of Developmental Biology in Brazil. Instead, it will be dedicated to highlighting one specific initiative that inspired a new generation of Developmental Biologists who established important research lines and contributed to the advance of this scientific field in Brazil.
Ancestral form and function of larval feeding structures are retained during the development of non-planktotrophic gastropods
Authors: Collin Rachel , Shishido Caitlin M. , Cornejo Anabell J. , Lesoway Maryna P.
Published: September 2020

Mode of development (MOD) is a key feature that influences the rate and direction of evolution of marine invertebrates. Although many groups include species with different MODs, the evolutionary loss of feeding larvae is thought to be irreversible, as the complex structures used for larval feeding and swimming are lost, reduced, or modified in many species lacking feeding larvae. This view is largely based on observations of echinoderms. Phylogenetic analysis suggests that feeding larvae have been re-gained in at least one species of calyptraeid gastropod. Further, its sister species has retained the velum, the structure used for larval feeding and swimming. Here, we document velar morphology and function in calyptraeids with 4 different MODs. Embryos of Crepidula navicella, Crepidula atrasolea, Bostrycapulus aculeatus, Bostrycapulus odites, Bostrycapulus urraca, Crepipatella dilatata, Crepipatella occulta, Crucibulum quiriquinae and Crepidula coquimbensis all hatch as crawling juveniles, yet only Crepidula coquimbensis does not make a well-formed velum during intracapsular development. The velar dimensions of 6 species with non-planktotrophic development were similar to those of planktotrophic species, while the body sizes were significantly larger. All of the species studied were able to capture and ingest particles from suspension, but several non-planktotrophic species may ingest captured particles only occasionally. Video footage suggests that some species with adelphophagic direct development capture but frequently fail to ingest particles compared to species with the other MODs. Together these lines of evidence show that, among calyptraeids at least, species that lack planktotrophic larvae often retain the structures and functions necessary to successfully capture and ingest particles, reducing the barriers to the re-evolution of planktotrophy
The “Mexican dancer” in Ecuador: molecular confirmation, embryology and planktotrophy in the sea slug Elysia diomedea
Authors: Moreano-Arrobo Lola , Pérez Oscar D. , Brown Federico D. , Oyarzún Fernanda X. , Canales-Aguirre Cristian B.
Published: September 2020

Elysia diomedea, otherwise known as the “Mexican dancer”, aries in adult size and color across its geographical distribution in Ecuador. Because of morphological variation and the absence of genetic information for this species in Ecuador, we analyzed mtDNA sequences in three populations (Ballenita, La Cabuya, and Mompiche) and confirmed that individuals from the three locations belonged to E. diomedea and that there was no population structure that could explain their morphological differences. Next, we analyzed general aspects about the reproductive biology and embryology of this species. Live slugs from the Ballenita population were maintained and reproduced ex situ. Egg ribbons and embryos were fixed and observed by brightfield and confocal microscopy. We observed a single embryo per capsule, 98 embryos per mm2 of egg ribbon, and compared the cleavage pattern of this species to that of other heterobranchs and spiralians. E. diomedea early development was characterized by a slight unequal first cleavage, occurrence of a 3-cell stage in the second cleavage, and the formation of an enlarged second quartet of micromeres. We observed clear yolk bodies in the egg capsules of some eggs ribbons at early stages of development. Both reproductive and embryological characteristics, such as presence of stomodeum in the larva, and ingestion of particles after hatching confirmed the planktotrophic veliger larvae of this species, consistent with the majority of sacoglossans from the Eastern and Northeast Pacific Oceans.
Inhibition of WNT/β-catenin is necessary and sufficient to induce Scx expression in developing tendons of chicken limb
Authors: Garcia-Lee Valentina , Díaz-Hernandez Martha E. , Chimal-Monroy Jesús
Published: September 2020

The cell differentiation of the musculoskeletal system is highly coordinated during limb development. In the distal-most region of the limb, WNT and FGF released from the apical ectodermal ridge maintain mesenchymal cells in the undifferentiated stage. Once the cells stop receiving WNT and FGF, they respond to differentiation signals. Particularly during tendon development, mesenchymal cells enter the cell differentiation program once Scleraxis (Scx) gene expression occurs. Among the signals that trigger the cell differentiation programs, TGFβ signaling has been found to be closely involved in tendon differentiation. However, whether Scx gene expression depends merely on TGFβ signaling or other signals is still not fully understood. In the present study, considering that WNT/β-catenin is an inhibitory signal of cell differentiation, we speculated possible antagonistic or additive effects between canonical Wnt/β-catenin and TGFβ/SMAD signaling pathways to control Scx gene expression. We found that the blockade of WNT/β-catenin promoted Scx gene expression. In contrast, the inhibition of TGFβ/SMAD signaling did not maintain Scx gene expression. Interestingly, the blockade of both WNT/β-catenin and TGFβ/SMAD signaling at the same time promoted Scx gene expression. Thus the inhibition of WNT/β-catenin signaling appears to be necessary and sufficient to induce Scx gene expression.
Oxygen, reactive oxygen species and developmental redox networks: Evo-Devo Evil-Devils?
Authors: Salas-Vidal Enrique , Méndez-Cruz Francisco J. , Ramírez-Corona Arlen , Reza-Medina Brenda
Published: September 2020

Molecular oxygen (O2), reactive oxygen species (ROS), and associated redox networks are cornerstones of aerobic life. These molecules and networks have gained recognition as fundamental players in mechanisms that regulate the development of multicellular organisms. First, we present a brief review in which we provide a historical description of some relevant discoveries that led to this recognition. We also discuss the fact that, despite its abundance in nature, oxygen is a limiting factor, and its high availability variation impacted the evolution of adaptive mechanisms to guarantee the proper development of diverse species under such extreme environments. Finally, some examples of when oxygen and ROS were identified as relevant for the control of developmental processes are discussed. We take into account not only the current knowledge on animal redox developmental biology, but also briefly discuss potential scenarios on the origin and evolution of redox developmental mechanisms and the importance of the ever-changing environment.
Developmental delay during eye morphogenesis underlies optic cup and neurogenesis defects in mab21l2u517 zebrafish mutants
Authors: Wycliffe Rebecca , Plaisancie Julie , Leaman Sydney , Santis Octavia , Tucker Lisa , Cavieres Daniela , Fernandez Michelle , Weiss-Garrido Camila , Sobarzo Cristian , Gestri Gaia , Valdivia Leonardo E.
Published: September 2020

Shaping the vertebrate eye requires evagination of the optic vesicles. These vesicles subsequently fold into optic cups prior to undergoing neurogenesis and allocating a population of late progenitors at the margin of the eye. mab21l2 encodes a protein of unknown biological function expressed in the developing optic vesicles, and loss of mab21l2 function results in malformed eyes. The bases of these defects are, however, poorly understood. To further study mab21l2 we used CRISPR/Cas9 to generate a new zebrafish mutant allele (mab21l2u517). We characterized eye morphogenesis and neurogenesis upon loss of mab21l2 function using tissue/cell-type-specific transgenes and immunostaining, in situ hybridization and bromodeoxyuridine incorporation. mab21l2u517 eyes fail to grow properly and display an excess of progenitors in the ciliary marginal zone. The expression of a transgene reporter for the vsx2 gene –a conserved marker for retinal progenitors– was delayed in mutant eyes and accompanied by disruptions in the epithelial folding that fuels optic cup morphogenesis. Mutants also displayed nasal-temporal malformations suggesting asynchronous development along that axis. Consistently, nasal retinal neurogenesis initiated but did not propagate in a timely fashion to the temporal retina. Later in development, mutant retinas did laminate and differentiate. Thus, mab21l2u517 mutants present a complex eye morphogenesis phenotype characterized by an organ-specific developmental delay. We propose that mab21l2 facilitates optic cup development with consequences both for timely neurogenesis and allocation of progenitors to the zebrafish ciliary marginal zone. These results confirm and extend previous analyses supporting the role of mab21l2 in coordinating morphogenesis and differentiation in developing eyes.
Bisphenol A alters differentiation of Leydig cells in the rabbit fetal testis
Authors: Ortega-García Alexis P. , Díaz-Hernández Verónica , Collazo-Saldaña Pedro , Merchant-Larios Horacio
Published: September 2020

The endocrine disruptor Bisphenol A (BPA) crosses the placental barrier and reaches the fetal organs, including the gonads. In the testis, fetal Leydig cells (FLC) produce testosterone required for the male phenotype and homeostatic cell-cell signaling in the developing testis. Although it is known that BPA affects cell proliferation and differentiation in FLC, results concerning the mechanism involved are contradictory, mainly due to differences among species. Fast developing fetal gonads of rodents lack cortex and medulla, whereas species with more extended gestation periods form these two tissue compartments. The rabbit provides a good subject for studying the disruptive effect of BPA in fetal Leydig and possible postnatal endocrine consequences in adult Leydig cells. Here, we investigated the impact of BPA administered to pregnant rabbits on the FLC population of the developing testes. Using qRT-PCR, we assessed the levels of SF1, CYP11A1, 3β-HSD, and androgen receptor genes, and levels of fetal serum testosterone were measured by ELISA. These levels correlated with both the mitotic activity and the ultrastructural differentiation of the FLC by confocal and electron microscopy, respectively. Results indicate that BPA alters the expression levels of essential genes involved in androgen paracrine signaling, modifies the proliferation and differentiation of the FLCs, and alters the levels of serum testosterone after birth. Thus, BPA may change the postnatal levels of serum testosterone due to the impaired FLC population formed by the proliferating stem and non-proliferating cytodifferentiated FLC.
Limb regeneration in salamanders: the plethodontid tale
Authors: Arenas-Gómez Claudia M. , Delgado Jean-Paul
Published: September 2020

Salamanders are the only vertebrates that can regenerate limbs as adults. This makes them ideal models to investigate the cellular and molecular mechanisms of tissue regeneration. Ambystoma mexicanum and Nothopthalmus viridescens have long served as primary salamander models of limb regeneration, and the recent sequencing of the axolotl genome now provides a blueprint to mine regeneration insights from other salamander species. In particular, there is a need to study South American plethodontid salamanders that present different patterns of limb development and regeneration. A broader sampling of species using next-generation sequencing approaches is needed to reveal shared and unique mechanisms of regeneration, and more generally, the evolutionary history of salamander limb regeneration.
Insights into vertebrate head development: from cranial neural crest to the modelling of neurocristopathies
Authors: Weiner Andrea M. J. , Coux Gabriela , Armas Pablo , Calcaterra Nora
Published: September 2020

Although the vertebrate head has evolved to a wide collection of adaptive shapes, the fundamental signalling pathways and cellular events that outline the head skeleton have proven to be highly conserved. This conservation suggests that major morphological differences are due to changes in differentiation and morphogenetic programs downstream of a well-maintained developmental prepattern. Here we provide a brief examination of the mechanisms and pathways responsible for vertebrate head development, as well as an overview of the animal models suitable for studying face development. In addition, we describe the criteria for neurocristopathy classification, highlighting the contribution of zebrafish to the modelling of Treacher Collins/Franceschetti Syndrome, an emblematic neurocristopathy. The contributions from our laboratory reveal that proper zebrafish head development depends on the fine-tuning of developmental-gene expression mediated by nucleic acid binding proteins able to regulate DNA conformation and / or the neuroepithelium redox state.
The levels of reprogramming factors influence the induction and maintenance of pluripotency: the case of CD1 mouse strain cells
Authors: Covarrubias Luis , Martínez-Sarmiento José-Ángel , Valencia Concepción , Nagy Andras , Hernández-García David
Published: September 2020

The amount of proteins of the regulatory pluripotency network can be determinant for somatic cell reprogramming into induced pluripotent stem cells (iPSCs) as well as for the maintenance of pluripotent stem cells (PSCs). Here, we report a transposon-based reprogramming system (PB-Booster) that allowed high expression levels of a polycistronic transgene containing Myc, Klf4, Oct4 and Sox2 (MKOS) and showed increased reprogramming efficiency of fresh mouse embryonic fibroblasts (MEFs) into iPSCs under low, but not under high, MKOS expression levels. In contrast, MEFs after 2 passages derived into a similar number of iPSC colonies as fresh MEFs at a high MKOS dose, but this number was reduced at a low MKOS dose. Timing of reprogramming was not affected by MKOS expression levels but, importantly, exogenous MKOS expression in established PSCs caused a significant cell loss. At high but not at low MKOS expression levels, MEFs of the CD1 strain produced more initial cell clusters than iPSCs and, although reprogrammed at a similar efficiency as MEFs of the 129/Sv strain, iPSCs could not be maintained in the absence of exogenous MKOS. In CD1-iPSCs, Oct4, Nanog, Rex1 and Esrrb expression levels were reduced when compared with the levels in PSCs derived from the 129/Sv strain. Culture of CD1-iPSCs in medium with MEK and GSK3β inhibitors allowed their self-renewal in the absence of exogenous MKOS, but the expression levels of Oct4, Nanog, Rex1 and Esrrb were only partially increased. Despite the reduced levels of those pluripotency factors, CD1-iPSC kept high capacity for contribution to chimeric mouse embryos. Therefore, levels of regulatory pluripotency factors influence reprogramming initiation and PSC maintenance in vitro without affecting their differentiation potential in vivo.
Cenefas y orlas caladas en la pintura romana de Hispania
Authors: Fernández Díaz Alicia , Castillo Alcántara Gonzalo
Published: September 2020

Las cenefas y orlas caladas constituyen un elemento característico de la pintura del IV estilo pompeyano y de la producción local en las provincias a partir de la segunda mitad del siglo I d.C., y hasta el siglo II d.C. aproximadamente, siendo un elemento clave para la datación e identificación de talleres itálicos y locales. El presente trabajo constituye una compendio y análisis de todas las documentadas en contextos hispanos con el objetivo de catalogarlas y establecer una clasificación en base a su tipología y cronología a partir de los datos contextuales obtenidos de cada uno de los yacimientos a los que corresponden. Pretendemos que este trabajo sirva de referencia para la futura identificación y datación de cenefas y orlas caladas, así como de los conjuntos que decoran.
La “ciudad ennegrecida”: esclavos en el Belém do Grão-Pará colonial
Authors: Silva Da Silva Marley Antonia , Costa Barbosa Benedito Carlos
Published: September 2020

La ciudad de Belém, ubicada al norte de la América portuguesa, tuvo como principales habitantes a los africanos y sus descendientes, durante el período comprendido entre 1755 y 1800. El propósito de este artículo es describir aspectos de la vida de la población negra en la capital del entonces estado de Grão-Pará, destacando las experiencias de las personas esclavizadas, no solo en el mundo laboral, sino en otros aspectos que nos permiten conocer su presencia en la ciudad. Las fuentes de investigación están compuestas, grosso modo, de documentos del Archivo Histórico de Ultramar (AHU), del Archivo Público de Pará y del Libro de Visitas del Santo Oficio de la Inquisición al Estado de Grão-Pará.
Gilberto Freyre y Roger Bastide sobre el Oriente íntimo en Brasil: ¿aculturación o transculturación?
Authors: González Alcantud José Antonio
Published: September 2020

La comparación de las obras sobre el Oriente y el Islam brasileños de Gilberto Freyre y Roger Bastide, amigos y colaboradores, nos permite plantearnos problemas tales como el de la aculturación y transculturación entre África y América. En este texto, emergen otras figuras de su tiempo como Mariátegui, Arguedas, Fernando Ortiz, Malinowski. En todos ellos late el antirracismo, la vindicación del mestizaje, y la simpatía, vía la Península Ibérica, por los “orientes”.
Iberismo, tradición y mestizaje: la defensa del Nordeste brasileño antiguo en el primer Gilberto Freyre (1920 a 1940)
Authors: Schneider Alberto Luiz
Published: September 2020

En este artículo se debate la producción intelectual de Gilberto Freyre entre las décadas de 1920 y 1940. Nuestro objetivo consiste en comprender no solamente las lecturas freyreanas alrededor del iberismo de Miguel de Unamuno, Ángel Ganivet y Ortega y Gasset, sino sobre todo investigar y registrar en la extensa obra de Freyre una continua defensa de la legitimidad histórica de la cultura ibérica que el autor veía amenazada ante la fuerza disgregadora del moderno Occidente industrial, protestante y capitalista.
Entrevista con Enrique García: impases en el desarrollo de América Latina
Authors: Dallari Pedro B. A.
Published: September 2020

Entrevista realizada por el Prof. Dr. Pedro Dallari, del Instituto de Relaciones Internacionales y coordinador del Centro Iberoamericano (Ciba) y de la Cátedra José Bonifácio de la Universidad de São Paulo (USP) al economista boliviano Enrique García, en diciembre de 2019. La entrevista forma parte de las actividades realizadas en el ámbito de la Cátedra José Bonifácio.
Debret, Gilberto Freyre, Cecília Meireles: representaciones del comercio callejero en Brasil y sus influencias orientales y africanas
Authors: Contatori Romano Luís Antônio
Published: September 2020

El comercio callejero ha existido en Brasil desde el período colonial, practicado por negros libres y esclavos. El objetivo de este estudio es mostrar aspectos de este comercio en ciudades como Rio de Janeiro y Recife, desde el período imperial hasta el Estado Novo del gobierno de Vargas, marcando influencias orientales, especialmente islámicas, introducidas por esclavos y colonizadores portugueses, hasta la llegada de nuevos inmigrantes europeos en las primeras décadas del siglo XX. Se parte del análisis de extractos e imágenes de obras de tres autores: Jean-Baptiste Debret, en Viagem Pitoresca e Histórica ao Brasil (1835-1839); Gilberto Freyre, en Casa-grande & Senzala (1933), Sobrados e Mucambos (1936) y Guia prático, histórico e sentimental do Recife (1934); Cecilia Meireles (1941), en la crónica “Through the Rio Streets”, publicada en la revista Travel in Brazil, ilustrada con fotografías de Jean Manzon, que registra la inserción del inmigrante europeo en el comercio callejero de Río de Janeiro. También se pretende mostrar la intersección entre este comercio y las concepciones de viajero y turista.
“Mi palabra es afilada y contamina”: análisis lingüístico-discursivo de comentarios racistas implícitamente manifestados en Facebook
Authors: Faria Lopes Viviane , Lainne Dos Santos Kets
Published: September 2020

Este trabajo es el resultado de la investigación y el análisis de los discursos racistas aparecidos en los comentarios de Facebook y publicados por los propios usuarios en la web de esta red virtual. Con el propósito de investigar y analizar discursos discriminatorios, centrándonos en aquellos de segregación manifiestamente implícita, se evaluó de qué modo dichas frases han contribuido al mantenimiento de las desigualdades resultantes de las relaciones sociales de dominación, con estrategias y recursos discursivos de movilización e influencia. Con este fin, los datos analizados son el resultado de una compilación basada en el método cualitativo e interpretativo, y han sido descritos y examinados desde la perspectiva del paradigma teórico-metodológico proporcionado por el Análisis Crítico del Discurso (ADC) y también por la concepción crítica de los datos. Estudios de ideología. El corpus está compuesto por cuatro muestras discursivas, una de las cuales se ilustra con una figura distinta en su disposición original. De esta forma, se descubrió que los sujetos / usuarios recurrieron a diversas estrategias prejuiciosas, con base ideológica, en sus discursos, aunque disimuladas, contribuyendo a la hegemonía de las desigualdades, donde prima la continuidad de los conflictos en las relaciones étnico-raciales.
Entre experiencias de tiempo y (re)configuraciones de la nación: lecturas de la historia frente a la construcción nacional en los discursos de “Brasil” en Oliveira Vianna y Sérgio Buarque de Holanda
Authors: Machado Bruno Daniel
Published: September 2020

En este texto proponemos un ejercicio hermenéutico y dialógico entre los discursos de dos intérpretes de la sociedad brasileña del siglo XX, Francisco José de Oliveira Viana y Sérgio Buarque de Holanda. Para ello, nuestra propuesta consiste en una aproximación entre los textos de estos pensadores para comprender sus lecturas de la historia nacional asociada al desafío teórico-político de construcción de la nación brasileña. Desde este ángulo metodológico, las imbricaciones entre historia, política y cultura pueden visualizarse desde el plano ensayístico de ambas interpretaciones históricas del pensamiento social, cuyo impacto, todavía hoy, en cierto modo, es contemporáneo.
Plataforma para Análise de Dados de Honeypots no Curto Prazo
Authors: Neves da Silva Gustavo José , Obelheiro Rafael
Published: September 2020

Honeypots are computing resources whose value lies in being probed,attacked, or compromised. They are security tools instrumentalin observing attackers’ behavior and understanding attack dynamics.Honeypots generate a large amount of monitoring data, whichare often processed and analyzed manually. This introduces a delayin the perception of atypical occurrences and changes in trends,often rendering a deeper analysis of such phenomena unfeasible.We introduce a platform for the periodic automated processing ofdata collected by honeypots. The platform generates statistics andgraphs from a set of traffic capture files in the PCAP format, andits modular design allows it to be easily extended and adapted toproduce different outputs.
Rede de Sensores Sem Fio para Monitoramento de Variáveis de Ambiente
Authors: José da Cunha Lucas , Roberto Oliveira Valim Paulo
Published: September 2020

This research has the objective of implementing a sensors networkfor monitoring variable of environments using an IoT(Internet ofThings) technology focused on low energy consumption and longrange. The idea is to implement this network using LoRa technologyand LoRaWaN protocol. For a better utilization, it will be used andtested different LoRa parameters to communicate the nodes aimingshow the impacts of these parameters changes in long range, withconsistent data and low power consumption.
Um Modelo de Rede Neural Convolucional para Classificação de Peças de Vestuário
Authors: Maria da Rocha Fernandes Anita , Hodecker Andrei
Published: September 2020

An algorithm capable of identifying clothing parts can be very useful for identifying a person´s social identity, among other applications. Convolutional neural networks models have been shown to be efficient in the task of image classification. This paper explores and analyzes models of convolutional neural networks in the task of classifying clothing parts by images. The models presented in this paper showed higher accuracy compared to non-convolutional models of the literature.
Detecção de Roubo de Computadores em Laboratório Usando Visão Computacional
Authors: Andrade Cordeiro Gabriel , Grockotzki Giovani , Junior de Azevedo Itamar , Mantovani João , Henrique da Silva Santos Matheus , Vinicius Poncio Ricardo , Mazetto Mendes Caroline
Published: September 2020

Computer theft in computer labs causes academic damage to coursesthat require this resource and ends up directly harming students. Inthis context, this paper describes a methodology applied to detectcomputer removal through video analysis in real-time. For eachframe, image processing and computer vision techniques were used,subtracting background information, binarization, segmentationof the region of interest and definition of contours. The case studywas developed at a Brazilian university. For theft detection, it wasconsidered a black computer tower case carried by people leavingthe laboratory. Monitoring is carried out by a camera positioned infront of the lab exit door. The software developed alerts a suspiciousactivity that may indicate a possible computer theft.
Rastreabilidade de alocação e desalocação de contêineres usando Docker Swarm com base em blockchain Hyperledger consorciado
Authors: Marques Marco , Pillon Maurício , Koslovski Guilherme , Miers Charles
Published: September 2020

Container-based virtualization technology enables dynamic allocation,addressing needs of scalability and fault tolerance. This featureprovides flexibility in the use of computing resources, but turnsmonitoring a challenge due to the large flow of calls and allocations.Recording these operations in a Blockchain allows to not only auditthe resources employed but also the chronology analysis of theperformed operations. In addition, the use of blockchain distributesthe credibility of record veracity between provider, end user, anddeveloper of the container-based solution.
Estudo da classificação de imagens a partir de sensoriamento remoto de Santa Catarina
Authors: Ricardo Bizon Artur , Pereira de Araújo Kohler Luciana , Luiz Nicoletti Adilson , Dal Bosco Fernanda , Yuri Andrade Marlon , Schramm da Silva Murilo , Bohn Pessatti Thales , Cesar Refosco Julio , Christian Vibrans Alexander , Liesenberg Veraldo
Published: September 2020

The mapping of the use of the land in a certain region allows theidentification of the available resources in it. In that way, the areaof remote sensoring searches for ways of processing large amountsof data with reliability in its results. This paper compares the automatedprocess of image, along with a spacial filter, with the imageedited manually. The overall accuracy for each categorized imageresulted in 71,3% for simple category, 72,6% for filtered categoryand 94,5% for manually edited category.
Dispositivo de IoT para Monitoramento e Controle Remoto de Condicionadores de Ar
Authors: Eduardo de Andrade Gil , Jorge F. da Silva Levy , Jonathan Hoss Diego
Published: September 2020

Electricity consumption in public education institutions compromisesan important part of the annual budget availableto finance expenses. These costs are even higher during theperiod between October and February, where the averagetemperatures are higher. The temperature increase in thisperiod is mainly related to the use of air conditioners. In thiscontext, intelligent solutions and devices capable of remotelymonitoring and controlling air conditioners can reduce energyconsumption and costs. Alternatively, the ARCO system isproposed, it’s composed of an IoT device capable of monitoringthe air conditioners, turning on and off when they receivea remote control. In addition to the designed hardware, thesystem also includes an application interface (API) and aweb application.
Processo para Reconhecimento e Tradução de Sinais em LIBRAS Utilizando Redes Neurais Artificiais
Authors: Pedro C. Sobrinho João , Pacheco H. da Silva Lucas , Dalpra Gabriella , Basilio Samuel
Published: September 2020

Recognized by law, the Brazilian Sign Language (LIBRAS), is thesecond Brazilian official language and, according to IBGE (BrazilianInstitute of Geography and Statistics), Brazil has a large communityof hearing-impaired people, with approximately nine million ofdeaf people. Besides that, most of the non-deaf community cannotcommunicate or understand this language. Considering that, theuse of LIBRAS’ interpreters becomes extremely necessary in orderto allow a greater inclusion of people with this type of disabilitywith the whole community. However, an alternative solution tothis problem would be to use artificial neural network methods forthe LIBRAS recognition and translation. In this work, a processof LIBRAS’ recognition and translation is presented, using videosas input and a convolutional-recurrent neural network, known asConvLSTM. This type of neural network receives the sequence offrames from the videos and analyzes, frame by frame, if the framebelongs to the video and if the video belongs to a specific class.This analysis is done in two steps: first, the image is analyzed inthe convolutional layer of the network and, after that, it is sent tothe network recurrent layer. In the current version of the implementednetwork, data collection has already been carried out, theconvolutional-recurrent neural network has been trained and it ispossible to recognize when a given LIBRAS’ video represents ornot a specific sentence in this language.
Detection of Depression Symptoms Using Chatbots Based on Machine Learning
Authors: Bastos Vitor , Felipe Monteiro André
Published: September 2020

Nowadays depression is a relevant issue due the high level of stressobserved even in students and young people. Moreover, the detectionof the depression symptons is a complex task, since eachperson has different behaviors and reactions in these scenarios. Thiswork address the detection of depression symptoms using chatbotsbased on machine learning algorithms. The use of chatbots enablesa smooth approach for shy and introspective people, whose donot feel comfortable for talking to parents, psychologists or medicalprofessionals in general. To this end, an App for smart-phoneis proposed in order to perform a talk with a person, and verifyif some depression symptoms are observed based using machinelearning algorithms. The initial results show that the proposedmodel has a good accuracy on simulated scenarios, where basictalks are performed by the chatbot.
API ACCESSIBILITY EXTRACTION∗ API para Extração de Parâmetros em Objetos de Aprendizagem Digital para Validação de Acessibilidade
Authors: De Fatima da Silva Juliana , André Dall’ Asta Maicon , J. Parreira Fábio , Binda Renan , Ribas Ulbricht Vânia , Renato Silveira Sidnei
Published: September 2020

This article presents the development of an API in NodeJs to automatically extract parameters in EPUB, DOCX and PDF digital learning objects. These parameters are used to check the degree of accessibility of Digital Learning Objects for people with hearing and visual impairments. The API uses refactoring techniques and the use of recursive functions, resulting in a JSON object that can be used by many programming languages. The article presents the results of preliminary tests, where it was found that EPUB files are better structured, leaving the parameters completely free to be extracted. The validation will be supported by the Development and Innovation group in Rehabilitation and Digital Assistive Technology (DIRTA-UFSM) and the accessibility team at the Social Media and Social Inclusion (LAMID) laboratory at the Federal University of Santa Catarina (UFSC).