Investigations of the Proyecto Arqueológico Tlajinga Teotihuacan (PATT) in 2019 focused on the southern neighborhood center of this cluster of non-elite residences in the southern periphery of the ancient Mexican metropolis. Our objective was to better understand the social infrastructure of public space within the district and how it tied its inhabitants together. Our methods included excavations at two large architectural complexes, geophysical prospection of these and adjacent structures and plazas, and chemical residue analysis of floors and sediments. They revealed architecturally elaborate complexes decorated with mural painting that appear to have been the loci of civic-ceremonial activities. Materials from the excavated portions of the complexes are inconsistent with residential uses, although it is possible that local elites lived elsewhere in the complexes or in others located nearby. The investigations therefore demonstrate that the semipublic spaces of neighborhood centers were distributed as distantly as this periphery of Teotihuacan and could be as elaborate as those in the urban epicenter, underscoring the city's more muted social inequality.

Estudios geofísicos, técnicas de sensores remotos y realización de mapas topográficos con GPS diferencial y vehículos aéreos no tripulados (VANT) han proporcionado una mejor comprensión de la organización espacial de los conjuntos departamentales y barrios en Teotihuacán. Nuestras investigaciones demuestran que en contraste con el mapa producido por el Teotihuacan Mapping Project (TMP) (Millon et al. 1973), el distrito de Tlanjinga es más rectangular y está más formalmente organizado, mientras que los conjuntos individuales tienen formas más irregulares, como lo había mostrado la excavación de Tlajinga 33 (Widmer y Storey 1993). Esto difiere de los nítidos cuadrados y rectángulos interpretados por las reconstrucciones arquitectónicas del TMP. El estudio de las imágenes satelitales mostró manchas blanquecinas en el terreno que parecen corresponder con áreas elevadas del mismo y con la desintegración de los aplanados de cal, destruidos por el tiempo y el trabajo agrícola. También verificamos la continuación del trazo de la Calzada de los Muertos que cruza este distrito mediante la modificación del relieve ocasionada por la excavación realizada en la toba volcánica subyacente (tepetate).

We investigate the structural evolution of Er/Si nanoclusters obtained in co-implanted fused silica upon annealing via Raman spectroscopy and transmission electron microscopy. The effect of annealing temperature (900–1200 °C) on the nature and the relative fraction of the formed amorphous-Si, Si nanocrystals (Si-nc), and amorphous Er nanoparticles (Er-np) was determined in this ternary Er–Si–O system, showing a change of growth regime above 1100 °C due to the formation of mixed Er/O/Si aggregates. We observe that the nucleation and growth of amorphous Er-np and Si-nc are mutually affected. The 2-fold increase in the size of Er-np when no excess Si+ is present in the matrix indicates that the formation of Si-nc in the proximity of Er clusters hinders Er diffusivity above 1100 °C. This finding shows the importance of nanoclustering for improving the thermal stability of Er-doped silica systems.

Recent work at La Laguna in Central Mexico provides an excellent illustration of the way in which information from architecture, food remains, ceramic vessels and chemical signatures can be brought together to demonstrate communal feasting associated with specific structures and public spaces. Structure 12M-3 contained a range of evidence indicative of food preparation and consumption. Ritual effigy vessels depicted deities connected with food and fertility, and fire and the hearth. Taken together, the several lines of evidence indicate that Structure 12M-3 was a special building, located directly behind the main temple and devoted to the preparation and production of communal feasts that were held in the adjacent plaza. This provides new insights into community life in the urban centres of early Mesoamerica.

The purpose of this study was to achieve a descellularized scaffold from cartilage tissue, which can be used as xenograft for cartilage tissue regeneration.

This work presents the results obtained using one method to wash porcine trachea in order to remove cellular material from the extracellular matrix and to avoid the immune reaction using enzymatic detergent and partial enzymatic degradation with Deoxyribonuclease I (DNase-I), Ethylenediaminetetraacetic Acid (EDTA) and Trypsin. This treatment was qualitatively evaluated by Scanning Electron Microscopy (SEM), and H&E Stain (Histology), and quantitatively evaluated by DNA quantification. The thermal characterization of the descellularized scaffold was carried out using Termogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The type of collagen obtained from the scaffold was determined through SDS-PAGE electrophoresis. When using Enzymatic Treatment (ET) to wash trachea tissue, it is possible to obtain an acellular xenograft; this procedure has the potential to avoid rejection reactions of the xenograft.

The photoluminescence (PL) of silicon nanocrystals (Si-nc) obtained by ion implantation in the oxide layer of a MOS structure was measured during the application of a slowly varying electric field generated by biasing the gate electrode. As a result, both PL intensity enhancement and quenching have been observed. These reproducible intensity modulations exhibit a hysteresis effect when the applied electric field is varied and persist even after it is removed. The behavior of the current density and the absence of wavelength shift in the PL spectra during gate voltage sweeps suggest that these modulations are related to the motion of charge carriers rather than to field-induced mechanisms such as quantum-confined Stark effect (QCSE).

Silicon nanocrystals (Si-nc) and amorphous silicon (a–Si) aggregates either produced by silicon implantation in fused silica have been studied by micro-Raman spectroscopy. Under certain experimental conditions, relevant information regarding both the dimension and the size distribution of Si-nc can be extracted from the energy shifts and the spectral distortion of the phonon excitation observed near 520 cm−1. Results are presented for different sample annealing times and ion fluences. These data agree with the direct observation by TEM of non-uniformly depth-distributed silicon nanocrystals. Moreover, measurements recorded for different Raman probing depths give evidence of chemical composition changes within the fused silica matrix. The depth evolution of the phonon peak associated with the Raman signature of a-Si near 470 cm−1 shows the presence of amorphous silicon, whose concentration is higher in the region where the large Si-nc are located.