Numerical analysis of lobular structures for biomimicry of a mammary gland structure

Francisco Josué Hernández Rangel ADRIANA DEL CARMEN GALLEGOS MELGAR AZAHEL DE JESUS RANGEL LOPEZ Pedro Cruz Alcantar (2022)

The mammary gland is an organ that has an internal structure formed by lobules, ducts and ligaments that perform both physiological and mechanical functions. This structure aesthetically defines the body and has the additional function of producing milk in mammals to support offspring. Currently, structures and shapes are being studied to imitate the nature of the mammary gland for medical applications such as prostheses, systems and models for surgeries, the most used technique for this is biomimetics. There are no models or devices that contemplate the internal structure of the mammary gland, so in this work different structures that imitate the lobular adjustment found in a real mammary gland are proposed, these structures were subjected to different load states to numerically evaluate and optimize the proposed structures. It was found that the triangular or lobular structures have better behavior in the distribution of deformations and stresses being excellent candidates to be part of biomedical applications.

Article

Biomimetics Biomedical structures Mammary gland Numerical analysis MEDICINA Y CIENCIAS DE LA SALUD CIENCIAS MÉDICAS OTRAS ESPECIALIDADES MÉDICAS OTRAS OTRAS

Population genetic structure of the maize weevil, Sitophilus zeamais, in southern Mexico

Martha Willcox (2023)

Article

Maize Weevil Genetic Structure CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AGRICULTURAL WORKERS FILTRATION GENE FLOW MAIZE SINGLE NUCLEOTIDE POLYMORPHISM SITOPHILUS ZEAMAIS CURCULIONIDAE

Exploring the genetic diversity and population structure of wheat landrace population conserved at ICARDA genebank

Ahmed Amri Carolina Sansaloni Ezgi Kurtulus Kumarse Nazari (2022)

Article

Wheat Landraces Genetic Diversity SNP Markers Analysis of Molecular Variance AMOVA CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA BREEDING DISCRIMINANT ANALYSIS GENETIC VARIATION GENETIC DISTANCE GENETIC IMPROVEMENT GENETIC MARKERS HEXAPLOIDY LANDRACES POPULATION STRUCTURE SINGLE NUCLEOTIDE POLYMORPHISM TRITICUM AESTIVUM WHEAT

Effect of F1 and F2 generations on genetic variability and working steps of doubled haploid production in maize

Evellyn Couto Massaine e Sousa Italo Granato Miriam Vidotti Jose Crossa Juan Burgueño Roberto Fritsche-Neto (2019)

Article

Doubled Haploid Tropical Germplasm Genetic Variability CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA DIPLOIDY GENETIC MARKERS GENETIC VARIATION GERMPLASM MAIZE POPULATION STRUCTURE SINGLE NUCLEOTIDE POLYMORPHISM PLANT BREEDING

Microstructure and microhardness evolution of additively manufactured cellular Inconel 718 after heat treatment with different aging times

Juan Manuel salgado Lopez Enrique Martinez-Franco celso cruz JORGE CORONA CASTUERA J. A. Villada (2022)

The manufacture of cellular structures using high-performance materials is possible thanks to the additive manufacturing of metals. However, it is well known that the mechanical and microstructural properties of metals manufactured by this technique do not correspond to those of the same metals manufactured by conventional methods. It is well known that the mechanical properties depend on the direction of manufacture, the size of the pieces, and the type of cell structure used. In addition, the effect of heat treatments on parts manufactured by additive manufacturing differs from parts manufactured by conventional methods. In this work, the microstructure and microhardness of cellular structures of Inconel 718, manufactured by additive manufacturing under heat treatments with different aging times, were evaluated. It was found that the time of the first aging impacts the microhardness and its homogeneity, affecting the microstructure. The highest hardness was obtained for an aging time of 8 h, while the lowest standard deviation was obtained at 10 h. Finally, it is shown that the aging time influences a more homogeneous distribution of the elements and phases.

Article

Additive manufacturing Inconel 718 Heat treatment Cellular structures Metamaterials INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS OTRAS ESPECIALIDADES TECNOLÓGICAS OTRAS OTRAS

Genetic diversity of huaya india (Melicoccus oliviformis Kunth), a neglected neotropical fruit crop

MONICA ILSY JIMENEZ ROJAS RUBEN HUMBERTO ANDUEZA NOH Obed I. Noh Ake Daniel Potter MATILDE MARGARITA ORTIZ GARCIA Renee S. Arias JAIME MARTINEZ CASTILLO (2021)

Currently, some species of Sapindaceae are important fruit crops worldwide. The Huaya India (Meliccocus oliviformis, Sapindaceae) is a neglected Neotropical fruit tree consumed locally in the Maya Lowlands of Mexico, where it exists in both wild and domesticated forms. Our objective was to evaluate the genetic diversity of the Huaya India in its possible domestication area and thus generate knowledge that serves as the basis for a commercial management. A total of 450 individuals collected from 15 natural vegetation sites and 15 Maya villages, were characterized using nine microsatellite loci and population genetics approaches were applied. STRUCTURE, Neighbor-Joining and PCoA analyses suggested the existence of three main groups: 1) one composed by 14 natural vegetation sites, 2) one integrated by 10 Maya villages plus one natural vegetation site, 3) one composed by five Maya villages. At the species level, genetic differentiation was high (FST = 0.562) and gene flow was low (Nm = 0.395); between genetic groups, differentiation was low and gene flow was high. Genetic diversity was low at the level species (HE = 0.19) and higher in the group composed for only natural vegetation sites. When we considered only two groups (natural vegetation sites vs Maya villages) to explore a possible bottleneck as a consequence of human management, the natural vegetation sites showed higher, and significant, genetic diversity (HE = 0.231) than the Maya villages (HE = 0.152). This study can serve as a basis to develop management strategies for Huaya India in the Maya Lowlands of Mexico, but without compromising its conservation.

Article

DOMESTICATION GENETIC STRUCTURE MAYA LOWLANDS OF MEXICO MICROSATELLITE MOLECULAR MARKERS PERENNIAL FRUIT SPECIES SAPINDACEAE SSR MARKERS YUCATAN PENINSULA BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) ECOLOGÍA VEGETAL ECOLOGÍA VEGETAL

Térmicos de estructuras tipo giroide fabricadas en Ti6Al4V por manufactura aditiva

Heat treatments on a Ti6Al4A giroid-type structure fabricated by additive manufacturing

Luis Kevin Ayala Gastelum JORGE CORONA CASTUERA John Henao Carlos Agustín Poblano Salas Juan Carlos Castro Sandoval (2022)

El Ti6Al4V es una de las aleaciones de titanio más utilizadas por sus propiedades físico- mecánicas y químicas para diferentes aplicaciones industriales, entre las que se incluyen la industria biomédica y la aeronáutica. En el presente trabajo se presenta la fabricación por manufactura aditiva DMLS de una estructura tipo giroide en Ti6Al4V que presenta potencial para aplicaciones estructurales. Las muestras de estructura tipo giroide fueron sometidas a tratamientos térmicos (TT) de solubilizado y envejecido (910°C/8h/WC) y recocidos (800°C/4h, 850°C/3h, y 870°C/2h, con enfriamientos en aire). Adicionalmente, el estudio incluye el análisis metalográfico de las muestras antes y después de los tratamientos térmicos aplicados. Los resultados revelan que se produce la precipitación de fases estables y/o metaestables según el tipo de tratamiento térmico aplicado a las muestras. Se realizaron pruebas de las propiedades mecánicas de las muestras antes y después del tratamiento térmico con el fin de correlacionar la microestructura obtenida con las propiedades mecánicas inducidas en el material. Se encontró que la dureza, módulo elástico, y punto de fluencia dependen del tipo tratamiento térmico aplicado; por ejemplo, se presenta un incremento de dureza y reducción en ductilidad de las muestras estudiadas con un TT de envejecido.

Ti6Al4V is one of the most widely used titanium alloys due to its physical-mechanical and chemical properties for different industrial applications, including the biomedical and aeronautical industries. In the present work we present the fabrication by DMLS additive manufacturing of a gyroid-type structure in Ti6Al4V that shows potential for structural applications. The gyroid-type structure samples were subjected to thermal treatments (TT) of solubilizing and aging (910°C/8h/WC) and annealing (800°C/4h, 850°C/3h, and 870°C/2h, with air cooling). Additionally, the study includes the metallographic analysis of the samples before and after the heat treatments applied. The results reveal that precipitation of stable and/or metastable phases occurs depending on the type of heat treatment applied to the samples. Tests of the mechanical properties of the samples before and after heat treatment were carried out in order to correlate the microstructure obtained with the mechanical properties induced in the material. It was found that the hardness, elastic modulus, and yield point depend on the type of heat treatment applied; for example, an increase in hardness and a reduction in ductility of the samples studied with an aging TT is presented.

Agradecimientos: Los autores agradecen al Programa de Becas Nacionales de CONACYT por el apoyo brindado en el proyecto. Agradecimientos al programa de posgrados de CIATEQ AC y al PICYT (Posgrado Interinstitucional en Ciencia y Tecnología) por el apoyo a la realización del presente trabajo al Dr. Jorge Corona y al Dr. John Henao.

Agradecimiento al programa “Investigadores por México” proyecto 848.

Article

Manufactura aditiva Estructura giroide Tratamientos térmicos Pruebas mecánicas DMLS Additive manufacturing Gyroid-type structure Heat treatment Mechanical tests INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS OTRAS ESPECIALIDADES TECNOLÓGICAS OTRAS OTRAS

Distribución de la diversidad genética de Tegeticula baja (Lepidoptera: Prodoxidae), polillas polinizadoras de yucas endémicas de la Península de Baja California

Distribution of the genetic diversity of Tegeticula baja (Lepidoptera: Prodoxidae), pollinating moths of endemic yucas from the Baja California Peninsula

Nicole Sicaeros Samaniego (2023)

La heterogeneidad del paisaje, la historia de la región y las interacciones ecológicas son factores que afectan la distribución espacial de la diversidad genética de las especies, porque influyen en el flujo génico entre poblaciones. Un ejemplo clásico de interacción ecológica es el mutualismo entre yucas y polillas de la yuca. Mientras las yucas necesitan de polillas adultas para su polinización, las polillas requieren de semillas en desarrollo de las yucas para que sus larvas se alimenten y se refugien. En la Península de Baja California, México, existen tres especies de yucas y al menos tres especies de polillas polinizadoras. La polilla Tegeticula baja poliniza a Yucca valida, Y. capensis y a poblaciones de híbridos de éstas. En este proyecto se evaluó el nivel de diversidad y el grado de estructuración genética de la polilla polinizadora T. baja en su área de distribución. Para esto se usaron 128 secuencias del marcador mitocondrial COI. Específicamente se evaluó si existe una estructura genética que sea congruente con la distribución alopátrica de sus hospedadores. Además, se generó un modelo de nicho ecológico bajo diferentes proyecciones históricas y actual. La diversidad haplotípica es alta (H= 0.708), en cambio, la nucleotídica es baja (Pi= 0.0015). Estos valores aunados con la prueba D de Tajima (-2.28, P<0.01) y un análisis “mismatch” indican una expansión demográfica. Los valores obtenidos para el índice de estructuración son bajos (Fst<0.07) al compararse las poblaciones según su hospedador. El modelo de nicho ecológico indica que las áreas con condiciones climáticas adecuadas para la ocurrencia de T. baja han variado a lo largo del tiempo, con la mayor cobertura en la actualidad. Se observó que la historia de la región afectó la diversidad y baja estructura de T. baja, mientras que no se encontró una diferenciación genética que coincida con la distribución de sus hospedadores. Se recomienda el uso de marcadores moleculares con un mayor nivel de variación para dilucidar el efecto de las interacciones ecológicas sobre la distribución de la variación genética de T. baja.

The heterogeneity of the landscape, the history of the region and ecological interactions influence the spatial distribution of species’ genetic diversity, because these influence genetic flow between populations. A classic example of an ecological interaction is the mutualism between yucas and yuca moths. While yucas need adult moths to pollinate their flowers, moths require the developing seeds of yucas for their larvae to feed on and take refuge. In the Peninsula of Baja California, Mexico there are three species of yucas and at least three species of pollinating yuca moths. The moth Tegeticula baja pollinates the species Yucca valida, Y. capensis and hybrid populations between the two. In this project we evaluated the level of genetic diversity and genetic structuring of the pollinating yucca moth T. baja in its geographical range. For this, 128 sequences from COI mitochondrial marker were used. Specifically, we evaluated if there’s genetic structuring that is congruent with the allopatric distributions of its hosts. Furthermore, an ecological niche model was constructed with past and present projections. Haplotype diversity is high (H= 0.708), while nucleotide diversity is low (Pi= 0.0015). The levels of genetic diversity joined with Tajima’s neutrality test and mismatch analysis indicate a population demographic expansion. The values obtained for the structure index were low (Fst <0.07) when comparing the population in accordance with their host. The ecological niche model indicates that the areas with the suitable climatic conditions have varied with time, with the greatest coverage during the present. In this study we observed that the history of the region affected the diversity and low structure of T. baja, and no genetic differentiation was observed in accordance with host geography. The use of molecular markers with a greater level of genetic variation is recommended to reveal the effect that ecological interactions have on the genetic diversity and structure of T. baja.

Master thesis

filogeografía, estructura, COI, diversidad, tegeticula phylogeography, structure, COI, diversity, tegeticula BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA OTRAS ESPECIALIDADES DE LA BIOLOGÍA OTRAS OTRAS

La arquitectura y la producción de imágenes de tarjeta postal. La invocación de la tradición versus el regionalismo crítico en Curitiba

Clara Irazabal (2001)

Curitiba, metrópoli de 2.5 millones de habitantes en el estado sureño de Panamá, Brasil, ha realizado grandes esfuerzos en los últimos 35 años por mejorar su imagen y calidad urbana, hasta el punto de alcanzar reconocimiento mundial y ser tenida por muchos como modelo de planeación y administración urbana. Si bien algunos de los aspectos de esta transformación han sido ampliamente documenta dos -como e l sistema de tránsito, la creación de parques urbanos y el desarrollo de programas de reciclaje- falta hacer aún una evaluación crítica de su experiencia. A fin de contribuir a esta tarea el presente ensayo intenta, a partir del fenómeno en Curitiba, una discusión teórica y empírica de lo que se ha convertido en una tendencia mundial del nuevo siglo como invención y consumo de tradición. Discuto cómo los temas de trasfondo vernáculo son utilizados por los funcionarios del gobierno local para invocar las tradiciones arquitectónicas internacionales en beneficio de la imagen urbana y el desarrollo turístico de su ciudad. Finalmente, propongo que el regionalismo crítico es un enfoque alternativo que puede aprovechar mejor las oportunidades de desarrollo arquitectónico y urbano, de modo que sirva a las necesidades de la región y la vincule con la economía global de manera competitiva.

Article

Urban renewal--Brazil--Curitiba. Vernacular architecture--Brazil--Curitiba. Curitiba (Brazil)--Buildings, structures, etc. Rehabilitación urbana. Arquitectura vernácula. HT178.B72 HUMANIDADES Y CIENCIAS DE LA CONDUCTA CIENCIAS DE LAS ARTES Y LAS LETRAS ARQUITECTURA DISEÑO ARQUITECTÓNICO

Gene flow and population structure in the Mexican blind cavefish complex (Astyanax mexicanus)

Martina Bradic Peter Beerli FRANCISCO JAVIER GARCIA DE LEON SARAI ESQUIVEL BOBADILLA (2012)

"Background

Cave animals converge evolutionarily on a suite of troglomorphic traits, the best known of which are eyelessness and depigmentation. We studied 11 cave and 10 surface populations of Astyanax mexicanus in order to better understand the evolutionary origins of the cave forms, the basic genetic structuring of both cave and surface populations, and the degree to which present day migration among them affects their genetic divergence.

Results

To assess the genetic structure within populations and the relationships among them we genotyped individuals at 26 microsatellite loci. We found that surface populations are similar to one another, despite their relatively large geographic separation, whereas the cave populations are better differentiated. The cave populations we studied span the full range of the cave forms in three separate geographic regions and have at least five separate evolutionary origins. Cave populations had lower genetic diversity than surface populations, correlated with their smaller effective population sizes, probably the result of food and space limitations. Some of the cave populations receive migrants from the surface and exchange migrants with one another, especially when geographically close. This admixture results in significant heterozygote deficiencies at numerous loci due to Wahlund effects. Cave populations receiving migrants from the surface contain small numbers of individuals that are intermediate in both phenotype and genotype, affirming at least limited gene flow from the surface.

Conclusions

Cave populations of this species are derived from two different surface stocks denoted "old" and "new." The old stock colonized caves at least three times independently while the new stock colonized caves at least twice independently. Thus, the similar cave phenotypes found in these caves are the result of repeated convergences. These phenotypic convergences have occurred in spite of gene flow from surface populations suggesting either strong natural or sexual selection for alleles responsible for the cave phenotype in the cave environment."

Article

Gene flow, population structure, Mexican blind cavefish BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) GENÉTICA ANIMAL GENÉTICA ANIMAL