José Luis Ruvalcaba Sil

Non-destructive in situ spectroscopic analysis of greenstone objects from royal burial offerings of the Mayan site of Palenque, Mexico

One of the most important Mayan cities of the Classic period (A.D. 200–900) of Mesoamerica is Palenque, in Chiapas. The Mayan civilization attributed great importance to greenstone minerals, in particular jadeite. This study covers the analysis of greenstones found in royal tombs of several temples corresponding to the Classic period: the Temple of the Skull, Temple of the Cross and Temples XVIII and XVIII-A. The aim of this research is to determine the use of greenstone minerals and the raw materials’ sources as a first step in understanding the development of Palenque and its relationships to other sites in the Maya region. Here, we present a non-destructive in situ study of lithic objects carried out by means of a several spectroscopic techniques, such as Raman, Fourier transform infrared (FTIR), X-ray fluorescence (XRF) and color measurements, at the Palenque site museum. FTIR and Raman allowed for the identification of minerals including jadeite, omphacite, amazonite, albite, muscovite and green quartz. Moreover, XRF was effective for in situ analysis of the elemental composition of the artifacts. This information was essential for sourcing the raw materials, in particular, jadeite. It was possible to infer the exploitation of an unknown source of jadeite for the earlier burial (A.D. 250–450). During this period the exploitation of the Verapaz and Motagua jadeite deposits also began. These sources were the primary deposits used for the manufacture of the artifacts studied from the period of A.D. 600–850. Also, a greater diversity of minerals is observed during the zenith of Palenque during this period, corresponding to the reign of Pakal. Although, between burials, the color of the artifacts is diverse, the color measurements indicated similarity in color among artifacts within individual burials.

DAVID A. SIQUEIROS: HIS MODIFICATION OF OIL- AND CELLULOSE NITRATE-BASED PAINT AND HIS ADVOCACY FOR INNOVATION, 1931–1949

Abstract Although the use of cellulose nitrate paint by David A. Siqueiros (1896–1974) is well documented, when and how he used it is not well established. This article focuses on a technical examination of six paintings Siqueiros made between 1931 and 1949. The paintings analyzed come from two collections: Museo Nacional de Arte in Mexico City and The Museum of Modern Art in New York. Findings presented here show that Siqueiros did not use cellulose nitrate for a painting he made in 1933, despite having made that claim decades later. Rather, evidence indicates Siqueiros used it in Mexico City just prior to his trip to New York in 1935 where he established a workshop to further explore innovation in painting technique and focus especially on ways to paint without a brush. Examination of a small work from 1936 or 1937 by Jackson Pollock (1912–1956), who attended the workshop, confirms he also experimented with the medium. Afterwards, in 1939, Siqueiros again altered his technique and materials in a way to suggest that rendering specific details in his paintings was more important than being restricted to the innovative “brush-free” effects developed in the workshop.

Nondestructive in situ XRF provenance study of Mesoamerican turquoise

Trabajo presentado en AIChE Annual Meeting, celebrado en Salt Lake City (Estados Unidos) del 8 al 13 de noviembre de 2015.The authors acknowledge the financial support of CINVESTAV and CONACYT (project number 39557-Y), both from Mexico. Berenice Fernandez-Arguijo thanks Eng. Felipe de Jesus Marquez-Torres of CINVESTAV-Saltillo for his assistance in the preparation of samples for SEM observations, as well as Eng. Carlos Palacios of Quimica del Rey, MET – MEX Penoles, who supplied the dolomite used in this work.Trabajo presentado en el XXIV Congreso Iberoamericano de Catalisis, celebrado en Medellin (Colombia) del 14 al 19 de septiembre de 2014.El presente trabajo reporta el estudio de la oxidacion catalitica de tolueno (1400 ppm) en catalizadores de Pd y Pt soportados en alumina promovida con 1 y 10% en peso de Ce. Los catalizadores se caracterizaron por: adsorcion fisica de N2 (BET), XRD, FTIR de piridina adsorbida, FTIR de la adsorcion de CO, XPS y TPO. Los resultados mostraron disminucion en el numero de sitios acidos con el contenido de cerio en el catalizador. Se observo una mayor dispersion en los catalizadores de Pd que en los de Pt. En los catalizadores de Pt solo se detectaron especies de Pt0 mientras que en Pd se detectaron especies de Pd0 y Pd2+. En ambas series de catalizadores la combustion total se alcanzo a contenidos de 1% peso en Ce, catalizadores Pd/ACe1 y Pt/ACe1, a 300oC. En el caso del Pd la combustion de tolueno dependen de las propiedades redox optimas (Ce3+/ Ce4+, Pd0/ Pd2+) por lo que resulta importante el tiempo de activacion del catalizador. La combustion catalitica de tolueno en Pt se vio favorecida en una superficie reductora por un proceso de demetilacion. El deposito de carbono en el catalizador disminuyo con el contenido de cerio en el catalizador debido a las propiedades redox del oxido de cerioPartial financial support from the Ministry of Science and Technology (Spain) (GrantMAT2002-04529-C03) and from CONACYT (Mexico) (fellowship to A.K. Cuentas-Gallegos) are gratefully acknowledged.Trabajo presentado en el XXIV Congreso Iberoamericano de Catalisis, celebrado en Medellin (Colombia) del 14 al 19 de septiembre de 2014.Tesis doctoral presentada por Kilian Laclavetine. Programa de doctorado de Fisica Nuclear, en el Departamento de Fisica Atomica, Molecular y Nuclear de la Universidad de Sevilla.Se propone la localizacion de fugas en redes de distribucion de agua medianteclasificadores basados en el metodo de los vecinos mas cercanos (k-NN) con metrica de distanciacosenoidal. El uso de distancias cosenoidales mejora la respuesta del clasificador, con relacional que usa metrica Euclidiana. Comparado con las tecnicas de localizacion de fugas basadasen la maxima correlacion de los residuos, se consigue una mayor robustez en condicionesaltamente ruidosas, y una menor dependencia del modelo hidraulico de la red, lo que facilita suimplementacion, pues no requiere del calculo de la matriz de sensibilidad. La tecnica propuestase programo en MATLABR©y se probo con datos sinteticos obtenidos de simulaciones conEPANET. La evaluacion del desempeno reportada se basa en el indice de perdidas (la fraccionde fugas localizadas erroneamente) y en una medida del error de localizacion obtenida de ladistancia topologicaTrabajo presentado en el XI Congreso de la Asociacion Iberica de Endocrinologia Comparada, celebrado en Vigo del 13 al 15 de julio de 2017.Resumen del trabajo presentado al 41st International Symposium on Archaeometry (ISA), celebrado en Kalamata (Grecia) del 15 al 21 de mayo de 2016.This study was financed by CONACYT-CB grant 240447 and logistically supported by MARN-El Salvador.Lanthanum chromite nano-particles, with a composition of La0.9Ca0.1CrO3 and La0.8Ca0.2CrO3, were produced by 1 h of hydrothermal reaction at 400 and 425??C respectively. The sintering of the powders was conducted using a spark plasma apparatus over the temperature range 1300-1550oC for 1 min with a constant loading pressure of 45 MPa. Additional sintering experiments using conventional firing were carried out for comparison. Fully densified (98 % r.d.) lanthanum chromite pellets with fine equiaxial grains 2.3 ?Em in size were obtained using the SPS (spark plasma sintering) method. n contrast, a maximum relative density of 97 % was produced using La0.8Ca0.2CrO3 sintered conventionally at 1400oC for 300 min, and the average grain size of the resulting sintered sample was 6 ?Em.Trabajo presentado al 10th Summer Workshop on Interval Methods, and 3rd International Symposium on Set Membership - Applications, Reliability and Theory, celebrado en Manchester (UK) del 14 al 16 de junio de 2017.The Application of Ixodicidas has been considered for a long time the alternative for control of the cattle tick Boophilus microplus, however, its use is currently limited in reducing tick infestations, due to the appearance of resistant field tick populations. Ixodicide resistance is a growing problem that needs to be attended, because, it is currently affecting the competitiveness of the Mexican Cattle industry in general and in particular the income of cattle producers. The solution to this problem needs to increase the budget dedicated to basic research in order to elucidate the molecular mechanisms of ixodicide resistance leading to the discovery of new molecular targets for ixodicide resistance detection and recombinant vaccine development. The recent use of new genomic tools, as well as reverse genetics approaches, will provide an extraordinary contribution to the improvement of tick control strategies and ixodicide resistance mitigation programs. The aim of the present review is to make a compilation of different topics related with acaricide resistance in the cattle tick Boophilus microplus, starting with some biological and molecular considerations on its new classification, to the analysis of ixodicide resistance, its impact on the Mexican cattle industry and the perspective of the genomic research in order to solve the problems associated to tick control, new diagnostic tools and development of tick vaccines.The present paper shows an interesting Optical Microscopy (OM) and Scanning Electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX) application to study degradation crust formation processes in Fort San Pedro, a historical building located at the colonial City of San Francisco de Campeche, Mexico; and the Cathedral of Seville, at Seville, Spain. The results show that while in Seville the crusts are consequence of sulfur dioxide reaction whit calcareous stone, leading to gypsum crystal formation (CaSO4 . 2H2O), in San Francisco de Campeche, deterioration crust are consequence of natural recrystallization processes of CaCO3 induced by excessive environmental humidity.Trabajo realizado en el Departamento de Biologia Molecular, CABIMER, y en el Departamento de Genetica, Facultad de Biologia, Universidad de Sevilla, para optar al grado de Doctor en Genetica Molecular y Biomedicina, por el Licenciado Andres Cruz Garcia.Proteases from the tentacles of the sea cucumber Isostichopusfuscus were partially purified and used to produce antioxidant peptides from body wall proteins of this marine species. Three proteins (105, 68, and 39 kDa) were identified by SDS-PAGE in the proteolytic extract of the tentacles. Protein hydrolyzates were generated with gelatin and crude protein substrates from body wall, and peptidic fractions lower and higher than 3 kDa were obtained to evaluate their oxygen radical scavenging capacity (ORAC). The 3 kDa-fraction obtained from the crude protein hydrolyzate showed the highest ORAC value (0.92 +/- 0.04 micromol Trolox equivalent/mg protein). This fraction was selected to purify peptides potentially responsible for the activity that might be used as ingredients for development of functional foods.The periphery of the archaeological city of Teotihuacan is going through a gradual process of destruction due to the unorganized urban growth of its neighboring communities; this has caused clashes between the National Institute of Archaeology and History (INAH) and said communities. This is a multifactorial problem that requires coordinated actions on behalf of the three levels of government involved. However, this article discusses the problem from a generational perspective, based on the fact that at this moment groups of schoolchildren and youth from these communities are creating their own opinions of the problem, learning from the placement of the people in conflict. In this context, we present the origin, development and current state of a scholastic archaeological news report called Archaeologists in a Jam, created with puppets and reported by the schoolchildren themselves, intended to stimulate critical thinking about the value, use and future of the conversation of this heritage.espanolCatalizadores de Pd, PdFe y PdCo fueron preparados por el metodo de impregnacion, usando borohidruro de sodio (NaBH4) como agente reductor y un material de carbono comercial, (Vulcan XC-72R) como soporte. Los electrocatalizadores sintetizados fueron probados para la reaccion de oxidacion de acido formico (FAOR, por sus siglas en ingles) en medio acido (H2SO4 0,5 M). La morfologia, la composicion y el tamano de particula de los electrocatalizadores se caracterizaron mediante tecnicas fisico-quimicas como difraccion de rayos X (XRD), microscopia electronica de barrido con espectroscopia por energia dispersiva (SEM-EDS) y microscopia electronica de transmision (TEM). La actividad catalitica se evaluo mediante tecnicas de voltamperometria ciclica (CV) y cronoamperometria (CA) EnglishPd, PdCo and PdFe catalysts were prepared by the impregnation method, using sodium borohydride (NaBH4) as the reducing agent and a commercial carbon material (Vulcan XC-72R) as support. The synthesized electrocatalysts were tested for the formic acid oxidation reaction (FAOR) in acid medium (H2SO4 0.5 M). The morphology, composition and particle size of the electrocatalysts were characterized by physicochemical techniques as X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The catalytic activity was evaluated by cyclic voltammetry (CV) and chronoamperometry techniques (CA)Al Consejo Nacional de Ciencia y Tecnologia (CONACyT, Mexico), por el apoyo economico (beca 354779) recibida durante parte de esta investigacion.Poster presentado a la 6th International Conference on Food Digestion (ICFD), celebrada en Granada (Espana) del 2 al 4 de abril de 2019.The authors acknowledge the financial support of the Mexican National Council of Science and Technology (CONACYT), through project number 31356-U, as well as through a scholarship granted to M.G.G. to carry out her Ph.D. studies at Cinvestav-Saltillo.The Major Intrinsic Protein (MIP) is a large family of integral membrane proteins with six putative transmembrane domains conserved throughout evolution. Members of this family have been identified in many organisms, ranging from bacteria to mammals. Functional data has been reported for some members of the different subfamilies (Chrispeels and Agre, 1994; Agre et al., 1995). There are MIPs that are thought to constitute relatively simple but selective channels for a variety of ions or small uncharged molecules. In the case of the bacterial glycerol facilitator GlpF, it has been shown that it facilitates glycerol, other polyhidric alcohols, urea and glycine uptake into E. coli (Maurel et al., 1994). For the bovine prototype MIP26, there is data showing that it serves as voltage-dependent anion channel (Ehring et al., 1990). Other MIP members have been shown to facilitate transport of water in plants and animals which are known as aquaporins (Chrispeels and Agre, 1994; Chrispeels and Maurel 1994). Different subfamilies have been identified by sequence comparisons which allows to distinguish animal and plant genes and that may help to recognize different functions of MIPs (Yamada et al., 1995). Interested in the function of proteins involved in water or solutes transport, we isolated a member of the MIP gene-family from common bean (Phaseolus vulgaris) using as probe a pea cDNA encoding a putative turgor responsive MIP (Guerrero et al., 1990). The sequence analysis of the putative PvMip-1 indicated that it can be classified within the subfamily of plant MIP genes encoding aquaporins. Northern-blot analysis showed that the PvMip-1 transcript is present in roots, leaves and stems. In spite of the high homology with the pea turgor responsive PsMip-7a cDNA, drought and ABA treatments doTrabajo presentado en el XXIV Congreso Iberoamericano de Catalisis, celebrado en Medellin (Colombia) del 14 al 19 de septiembre de 2014.Resumen del trabajo presentado al 25th international Congress on X-ray optic and microanalysis (ICXOM), celebrado en EE.UU. del 5 al 9 de agosto de 2019.

Technological study of pre-Columbian bimetallic discs from Monte Alban, Oaxaca, Mexico

One of the most remarkable examples of metalwork from Mesoamerica is the collection from Monte Alban’s Tomb 7. Among its items, we encounter extraordinary examples of bimetallic artefacts; a pair of solar representations whose main particularity is that they are formed by two different alloy sheets: one rich in silver and the other rich in gold. The silver-rich zones show deterioration characterized by brittleness, fractures and the loss of some fragments; this fragility is apparently due to dislocations caused by repeated hammering and insufficient annealing during the manufacturing process. Because sampling of the original items was not allowed, test specimens were prepared replicating the manufacturing techniques and alloy compositions, based on data previously obtained by X-ray Fluorescence Analysis of the original pieces. Examination of these test specimens was undertaken in order to understand the thermodynamic behaviour of the metallic microstructure and its relation to the alteration processes. Samples of each alloy were then taken and analyzed by metallographic methods.