1,058 research outputs found
Oral History Transcript - Elvira de la Garza
https://scholarworks.utrgv.edu/spanishlandgrantsoralhistories/1031/thumbnail.jp
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No Entiendo: The Effects of Bilingualism on Hispanic Earnings
This paper examines whether the ability to communicate in English and Spanish is rewarded in labor markets. Using data from the 2000 U.S. Census we find that among Hispanics, earnings are higher as the ability to speak English increases. We also find that bilingualism, is associated with higher wages reversing the negative effect found in earlier studies. The reversal could be explained by increasing immigration, and from economic integration with Latin America. Our results also show that bilingualism is negatively correlated with wages among different occupational categories and sectors, but particularly among managers and those employed in the public sector
“CLUPS”: A New Culture Medium for the Axenic Growth of Entamoeba histolytica
Amebiasis remains a major health problem in Mexico. Terefore, the search for better culture media and low-cost diagnostic and therapeutic tools is fundamental. We present a new culture medium for Entamoeba histolytica which allows the microbe to preserve its virulence factors and ability to induce hepatic abscesses in animal models. Te novel CLUPS medium is an improved version
of the PEHPS medium, previously designed in our laboratory. Te main diference is the substitution of raw beef liver in PEHPS by raw beef lung in the CLUPS medium. To compare the performance of three-culture media (traditional TYI-S-33, PEHPS, and CLUPS), E. histolytica trophozoites were cultured in quintuplicate, followed by the evaluation of phospholipase activity and the
induction of liver abscesses in golden hamsters. E. histolytica trophozoites grew signifcantly better in CLUPS medium than in TYIS-33. Likewise, CLUPS-cultured trophozoites produced signifcantly more phospholipases than TYI-S-33-cultured trophozoites. Finally, trophozoites grown in any of the three tested media had similar potential to induce liver abscesse
X-ray determination of compressive residual Stresses in spring steel generated by high-speed water Quenching
Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about -700 MPa were obtained.Peer ReviewedPostprint (published version
Epidermal growth factor enhances osteogenic differentiation of dental pulp stem cells in vitro
Introduction: Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) play an important role in
extracellular matrix mineralization, a complex process required for proper bone regeneration, one of the biggest
challenges in dentistry. The purpose of this study was to evaluate the osteogenic potential of EGF and bFGF on
dental pulp stem cells (DPSCs).
Material and methods: Human DPSCs were isolated using CD105 magnetic microbeads and characterized by flow
cytometry. To induce osteoblast differentiation, the cells were cultured in osteogenic medium supplemented with EGF or bFGF at a low concentration. Cell morphology and expression of CD146 and CD10 surface markers were
analyzed using fluorescence microscopy. To measure mineralization, an alizarin red S assay was performed and
typical markers of osteoblastic phenotype were evaluated by RT-PCR.
Results: EGF treatment induced morphological changes and suppression of CD146 and CD10 markers. Additionally, the
cells were capable of producing calcium deposits and increasing the mRNA expression to alkaline phosphatase (ALP) and osteocalcin (OCN) in relation to control groups (p < 0.001). However, bFGF treatment showed an inhibitory effect.
Conclusion: These data suggests that DPSCs in combination with EGF could be an effective stem cell-based therapy for bone tissue engineering applications in periodontics and oral implantology
Influence of the Delta Phase in the Microstructure of the Inconel 718 subjected to “Delta-processing” Heat Treatment and Hot Deformed
AbstractInconel 718 (IN718) is a nickel base alloy widely used in the aerospace industry due to its mechanical stability at elevated temperatures. Stable δ phase with acicular morphology weakens the IN718, however, it has been found that a spherical morphology distributed in the grain boundaries acts as an anchor preventing grain growth during hot deformation. The delta processing (DP718) is a saturation of δ phase in the alloy by thermal treatment followed by thermomechanical working to control the grain growth and morphology during deformation. Two specimens (A and B) of IN718 alloy were solubilized for 1h at 1100°C WQ and aging at 900°C for 24hWQ thermal treatment, following bythermomechanical deformation. Sample A was deformed at 0.001 s -1 and sample Bat 0.01 s-1, both deformations were carried out at 960°C and the final microstructures were characterized by optical microscopy and scanning electron microscopy (SEM) in order to evaluate morphology and grainsize distribution
Characterization of Corrosion Behavior of Painted Galvanized Steel under Accelerated Conditions
In the present study three systems of carbon steel (1008) are evaluated, which were provide of two corrosion control methods, barrier and cathodic protection (painted and galvanized respectively) commonly used in the construction industry. They were evaluated under accelerated conditions exposed in fog chamber, according to ASTM B-117, which specifies continues exposition of sodium chloride at 5% and 35 °C. The main aim of the research was to characterize the corrosion resistance and to determine the degradation mechanism under test’s conditions. The results after 1080 and 3500 hours of exposure are presented, with adhesion measure (ASTM D-3359) and scratch resistance measure (D-1654) for each exposure time, as well as the characterization of corrosion attack through the mapping analysis of Scanning Electron Microscope / Energy Dispersive X-ray. According to the results it is proposed that the corrosion of the systems under study begins at galvanized – metal base interface. Later advances due to formation of porous layer of zinc hydroxi-chloride, which it’s characteristic of environments with chloride ions, forming zinc’s corrosion products like zinc oxide and zinc hydroxide on the porous layer until iron starts to dissolve, producing iron oxide and iron oxy-hydroxide on the zinc’s corrosion products and porous layer
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