Please use this identifier to cite or link to this item: https://hdl.handle.net/20.500.12104/44113
Title: Relaxations in chitin: Evidence for a glass transition
Author: Gorostiza, A.
Acunha-Alonzo, V.
Regalado-Liu, L.
Tirado, S.
Granados, J.
Samano, D.
Rangel-Villalobos, H.
Gonzalez-Martin, A.
Issue Date: 2012
Abstract: The study of genetic information can reveal a reconstruction of human population's history. We sequenced the entire mtDNA control region (positions 16.024 to 576 following Cambridge Reference Sequence, CRS) of 605 individuals from seven Mesoamerican indigenous groups and one Aridoamerican from the Greater Southwest previously defined, all of them in present Mexico. Samples were collected directly from the indigenous populations, the application of an individual survey made it possible to remove related or with other origins samples. Diversity indices and demographic estimates were calculated. Also AMOVAs were calculated according to different criteria. An MDS plot, based on FST distances, was also built. We carried out the construction of individual networks for the four Amerindian haplogroups detected. Finally, barrier software was applied to detect genetic boundaries among populations. The results suggest: a common origin of the indigenous groups; a small degree of European admixture; and inter-ethnic gene flow. The process of Mesoamerica's human settlement took place quickly influenced by the region's orography, which development of genetic and cultural differences facilitated. We find the existence of genetic structure is related to the region's geography, rather than to cultural parameters, such as language. The human population gradually became fragmented, though they remained relatively isolated, and differentiated due to small population sizes and different survival strategies. Genetic differences were detected between Aridoamerica and Mesoamerica, which can be subdivided into "East", "Center", "West" and "Southeast". The fragmentation process occurred mainly during the Mesoamerican Pre-Classic period, with the Otomó being one of the oldest groups. With an increased number of populations studied adding previously published data, there is no change in the conclusions, although significant genetic heterogeneity can be detected in Pima and Huichol groups. This result may be explained because populations historically assigned as belonging to the same group were, in fact, different indigenous populations. " 2012 Gorostiza et al.",,,,,,"10.1371/journal.pone.0044666",,,"http://hdl.handle.net/20.500.12104/44113","http://www.scopus.com/inward/record.url?eid=2-s2.0-84866546267&partnerID=40&md5=f7ca307862e3ffb5f6c8c67c2b7a2fc0",,,,,,"9",,"PLoS ONE",,,,"7",,"Scopus
WOS",,,,,,,,,,,,"Reconstructing the History of Mesoamerican Populations through the Study of the Mitochondrial DNA Control Region",,"Article" "45978","123456789/35008","Nodora, J.N., Moores University of California San Diego Cancer Center, University of California, San Diego, San Diego, CA, United States; Gallo, L., San Diego State University, San Diego, CA, United States; Cooper, R., San Diego State University, San Diego, CA, United States; Wertheim, B.C., Arizona Cancer Center, University of Arizona, Tucson, AR, United States; Natarajan, L., Moores University of California San Diego Cancer Center, University of California, San Diego, San Diego, CA, United States; Thompson, P.A., Arizona Cancer Center, University of Arizona, Tucson, AR, United States; Komenaka, I.K., Department of Surgery, Maricopa Medical Center, Phoenix, AR, United States; Brewster, A., University of Texas M.D. Anderson Cancer Center, Houston, TX, United States; Bondy, M., Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, United States; Daneri-Navarro, A., University of Guadalajara, Guadalajara, Mexico; Meza-Montenegro, M.M., Instituto Tecnológico de Sonora, Ciudad Obregón, Mexico; Gutierrez-Millan, L.E., University of Sonora, Hermosillo, Mexico; Martínez, M.E., Moores University of California San Diego Cancer Center, University of California, San Diego, San Diego, CA, United States
Daneri-Navarro, Adrián., Universidad de Guadalajara. Centro Universitario de Ciencias de la Salud",,"Nodora, J.N.
Gallo, L.
Cooper, R.
Wertheim, B.C.
Natarajan, L.
Thompson, P.A.
Komenaka, I.K.
Brewster, A.
Bondy, M.
Daneri-Navarro, Adrián
Meza-Montenegro, M.M.
Gutierrez-Millan, L.E.
Martinez, M.E.",,"2014",,"Background: We compared the distribution of breast cancer reproductive and hormonal risk factors by level of acculturation and country of residence in women of Mexican descent. Methods: To compare the distribution of breast cancer reproductive and hormonal risk factors by level of acculturation and country of residence in women of Mexican descent, taking into account level of education, we analyzed data on 581 Mexican and 620 Mexican American (MA) women with a history of invasive breast cancer from the Ella Binational Breast Cancer Study. An eight-item language-based acculturation measure was used to classify MA women. Multivariate logistic regression was used to test associations between language acculturation, country of residence, and reproductive and hormonal risk factors. Results: After adjustment for age and education, compared to women residing in Mexico, English-dominant MAs were significantly more likely to have an earlier age at menarche (<12 years; odds ratio [OR]=2.08; 95% confidence interval [CI], 1.30-3.34), less likely to have a late age at first birth (?30 years; OR=0.49; 95% CI, 0.25-0.97), and less likely to ever breastfeed (OR=0.13; 95% CI, 0.08-0.21). Conclusions: Differences in reproductive and hormonal risk profile according to language acculturation and country of residence are evident; some of these were explained by education. Results support continued efforts to educate Mexican and MA women on screening and early detection of breast cancer along with promotion of modifiable factors, such as breastfeeding. © Mary Ann Liebert, Inc.",,,,,,"10.1089/jwh.2013.4498",,,,"http://www.scopus.com/inward/record.url?eid=2-s2.0-84902206196&partnerID=40&md5=fb5e52372e4c3d2e496e75030966c27a
http://hdl.handle.net/20.500.12104/44199",,,,,,"6",,"Journal of Women's Health",,"532
540",,"23",,"Scopus
WOS",,,,,,,,,,"Reproductive and hormonal risk profile according to language acculturation and country of residence in the ella binational breast cancer study",,,,"Article", "45957","123456789/35008",,"Campos, J.B.G., Cinvestav Querétaro, Fracc. Real de Juriquilla Querétaro, Libramiento norponiente No. 2000, Qro., 76230, Mexico; Prokhorov, E., Cinvestav Querétaro, Fracc. Real de Juriquilla Querétaro, Libramiento norponiente No. 2000, Qro., 76230, Mexico; Luna-Bárcenas, G., Cinvestav Querétaro, Fracc. Real de Juriquilla Querétaro, Libramiento norponiente No. 2000, Qro., 76230, Mexico; Galván, A.M., Cinvestav Querétaro, Fracc. Real de Juriquilla Querétaro, Libramiento norponiente No. 2000, Qro., 76230, Mexico; Sanchez, I.C., Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78703, United States; Donlucas, S.M.N., Departamento de Ingeniería Química, Universidad de Guadalajara, Blvd. M. García Barragán No. 1451, Guadalajara, Jal., 44430, Mexico; García-Gaitan, B., Division de Estudios de Posgrado e Investigación, Instituto Tecnológico de Toluca, Metepec, Edo. de MEX 52140, Mexico; Kovalenko, Y., Centro de Tecnología Avanzada (CIATEQ), Calzada del Retablo 150, 76150 Querétaro, Mexico",,"Campos, J.B.G.
Prokhorov, E.
Luna-Barcenas, G.
Galvan, A.M.
Sanchez, I.C.
Donlucas, S.M.N.
García-Gaitan, B.
Kovalenko, Y.",,"2009",,"Relaxations in chitin have been investigated in the temperature range 298-523 K using impedance spectroscopy in the frequency range 10 -1-108 Hz. The objective was to detect a glass-transition temperature for this naturally occurring, semicrystalline polysaccharide. The impedance study was complemented with X-ray diffraction, thermogravimetric, and differential scanning calorimetry measurements. Preliminary impedance data treatment includes the subtraction of the dc conductivity contribution, the exclusion of contact and interfacial polarization effects, and obtaining a condition of minimum moisture content for further analysis. When all these aspects are taken into account, two relaxations are clearly revealed in the impedance data. For the first time, evidence is presented for a relaxation process, which exhibits a non-Arrhenius temperature dependence, in dry ?-chitin (? 0.1% moisture content), and likely represents the primary ?-relaxation. This evidence suggests a glass transition temperature for chitin of 335 ± 10 K estimated on the basis of the temperature dependence of the conductivity and of the relaxation time. A second relaxation in dry ?-chitin, not previously reported in the literature, is observed from 353 K to the onset of thermal degradation (?483 K) and is identified as the rrelaxation often associated with proton mobility. It exhibits a normal Arrhenius-type temperature dependence with activation energy of 113 ? 3 kJ/mol. The latter has not been previously reported in the literature. A high frequency secondary ?-relaxation is also observed with Arrhenius activation energy of 45 activation energy of 45 activation energy of 45 1 kJ/mol 1 kJ/mol 1 kJ/mol. " 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 932-943, 2009.
URI: http://hdl.handle.net/20.500.12104/44178
http://www.scopus.com/inward/record.url?eid=2-s2.0-65649130003&partnerID=40&md5=990ad06daba903dfbffe5372a9e89176
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