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Puebla de Zaragoza, Mexico

Merlo J.M.,Tecnolgico de Monterrey | Aguilar J.F.,Instituto Nacional Of Astrofsica Ptica Y Electrnica | Mart-Panameo E.,Benemerita University Autnoma Of Puebla
Review of Scientific Instruments

We study the interaction distance in the lateral force detection, using a standard quartz tuning fork as a force transducer. That is the distance at which the interaction sample-probe starts to be detected. We study in particular the dependence on the approaching angle. For angles smaller than 0.366 radians, we found an exponential behavior of the interaction distance as a function of the approaching angle. We show an equation that adjusts well with the experimental data, and discuss the possible phenomena. © 2011 American Institute of Physics. Source

Estevez J.O.,Benemerita University Autnoma Of Puebla | Arriaga J.,Benemerita University Autnoma Of Puebla | Mendez-Blas A.,Benemerita University Autnoma Of Puebla | Robles-Chirez M.G.,Unidad University | Contreras-Solorio D.A.,Unidad University
Journal of Applied Physics

We report experimental results of the reflectance spectra of deterministic aperiodic multilayer structures fabricated with porous silicon. The refractive index of the layers forming the structures follows the values generated by the self-similar sequence called the 1s-counting sequence. We fabricated samples with 64, 128, and 256 layers with different thicknesses and porosities by controlling the applied current density and the etching time. The measured reflectance spectra exhibit properties of self-similarity, which are in good agreement with theoretical results reported previously. © 2012 American Institute of Physics. Source

Zamora-Ginez I.,Benemerita University Autnoma Of Puebla | Baez-Duarte B.G.,Benemerita University Autnoma Of Puebla | Brambila E.,Benemerita University Autnoma Of Puebla
Annals of Human Biology

Background: Independent of obesity, family history of type 2 diabetes mellitus (FHT2DM) is another important risk factor for developing diabetes.Aim: To establish the association among FHT2DM, risk factors for diabetes and cardiovascular disease in subjects from central Mexico.Subjects and methods: Clinical and biochemical studies were performed in 383 first-degree relatives of patients with type 2 diabetes and 270 subjects unrelated to patients with type 2 diabetesall subjects were from the city of Puebla in central Mexico. Logistic regressions were used to assess the association between FHT2DM and metabolic parameters. Cardiovascular risk was classified by dyslipidemia and the Framingham Risk Score (FRS).Results: FHT2DM was associated with risk factors for diabetes, such as increased fasting insulin levels (OR = 1.731, 95% CI = 1.0412.877), decreased insulin sensitivity (OR = 1.951, 95% CI = 1.2363.080) and pre-diabetes (OR = 1.63, 95% CI = 1.142.33). FHT2DH was not associated with risk factors for cardiovascular disease, such as dyslipidemia (OR = 1.12, 95% CI = 0.701.79) and FRS (OR = 0.74, 95% CI = 0.401.36) when adjusted for gender, age, smoking and obesity.Conclusion: Diabetic risk factors, but not cardiovascular disease risk factors, are associated with a positive family history of diabetes in subjects from central Mexico, independent of the presence of obesity. © 2012 Informa UK, Ltd. Source

Coyopol A.,Benemerita University Autnoma Of Puebla | Garcia-Salgado G.,Benemerita University Autnoma Of Puebla | Diaz-Becerril T.,Benemerita University Autnoma Of Puebla | Juarez H.,Benemerita University Autnoma Of Puebla | And 5 more authors.
Journal of Nanomaterials

The interest in developing optoelectronic devices integrated in the same silicon chip has motivated the study of Silicon nanocrystals (Si-ncs) embedded in SiO x (nonstoichiometric silicon oxides) films. In this work, Si-ncs in SiO x films were obtained by Hot Wire Chemical Vapor Deposition (HWCVD) at 800, 900, and 1000°C. The vibration modes of SiO x films were determined by FTIR measurements. Additionally, FTIR and EDAX were related to get the proper composition of the films. Micro-Raman studies in the microstructure of SiO x films reveal a transition from amorphous-to-nanocrystalline phase when the growth temperature increases; thus, Si-ncs are detected. Photoluminescence (PL) measurement shows a broad emission from 400 to 1100nm. This emission was related with both Si-ncs and interfacial defects present in SiO x films. The existence of Si-ncs between 3 and 6nm was confirmed by HRTEM. Copyright © 2012 A. Coyopol et al. Source

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