Browsing by Author "Xiao, Y"
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Item Open Access Comparison of methods for fullerene detection and measurements of reactive oxygen production in cosmetic products(Environmental Engineering Science, 2010-09-01) Chae, SR; Hotze, EM; Xiao, Y; Rose, J; Wiesner, MRNumerous commercial products incorporate novel engineered nanomaterials such as gold, silica, zinc oxide, and fullerenes in complex matrices such as polymer composites, creams, and textiles. Analytical methods for detecting nanomaterials in complex matrices are not well developed. Moreover, nanomaterial content and properties of these commercial products are typically unknown and protected for proprietary reasons. This study had two primary aims: detection of C60 within commercial face creams to establish a baseline concentration in these products (the first time this has been performed) and detection of residual C60 reactivity remaining in the products aged in water under various light conditions with a view toward environmental exposure assessment. To achieve these aims, three commercial creams advertised as containing the fullerene nanomaterials were investigated using a range of analytical techniques. Among the detection methods tested, only extraction followed by high-performance liquid chromatography was able to detect fullerenes in these products. The measured quantities of C60 in these creams represented <0.005% (w/w) with an unknown yield because total amounts added to the creams were unknown. Production of reactive oxygen species from these face creams was measured after aging them in water as well as exposing them to solar spectrum illumination or ultraviolet light, or storage in the dark. Singlet oxygen generated in the products after 48 h of aging was correlated with the amounts of C60 extracted from preaged samples, indicating residual photochemical reactivity and pointing toward the long-term impacts of utilizing these materials in commercial products. © 2010, Mary Ann Liebert, Inc.Item Open Access Extensive haplotype diversity in African American mothers and their cord blood units.(Tissue antigens, 2013-01) Tu, B; Leahy, N; Yang, R; Cha, N; Kariyawasam, K; Hou, L; Xiao, Y; Masaberg, C; Pulse-Earle, D; Maiers, M; Ng, J; Kurtzberg, J; Hurley, CKHLA-A, -B, -C, -DRB1, -DQB1 assignments were obtained for 374 pairs of African American mothers and their umbilical cord blood units (CBU) by DNA sequencing. An algorithm developed by the National Marrow Donor Program was used to assign 1122 haplotypes by segregation. Seventy percent of the haplotypes carried assignments at all five loci. In the remainder, alleles at various loci, most often DQB1 in 48% of the haplotypes with a missing assignment, could not be assigned due to sharing of both alleles by mother and CBU. There were 652 haplotypes carrying a unique combination of alleles at the five loci; the majority (74%) were singletons. Novel B∼C and DRB1~DQB1 associations were observed. The results show the genetic diversity in this population and provide validation for a publically available tool for pedigree analysis. Our observations underscore the need for procurement of increased numbers of units in the national cord blood inventory in order to identify matching donors for all patients requiring hematopoietic stem cell transplantation.Item Open Access Optimal Monitoring Schedule in Dynamic Contracts(2017-09-16) Chen, M; Sun, P; Xiao, YItem Open Access Relationship between giant panda populations and selected ecosystem services(Ecosystem Services, 2020-08-01) Zhang, J; Pimm, SL; Xu, W; Shi, X; Xiao, Y; Kong, L; Fan, X; Ouyang, ZThe Convention on Biological Diversity's Aichi Targets address both biodiversity and ecosystem services. We explore the relationship between giant panda populations and three ecosystem services: carbon sequestration, water retention, and soil retention. Do pandas prefer areas with higher than average values of these services? Areas may be good for pandas but not for these ecosystem services, and vice versa. Answering these questions can focus panda conservation. We map their spatial distribution and temporal changes from 2000 to 2015, by watershed, to target future protected areas for both pandas and these ecosystem services. Pandas occupy watersheds with above-average carbon sequestration and water retention. There is no tendency for pandas to be increasing in watersheds that have higher than average values of these ecosystem services or in watersheds where they are improving. Protected areas represented watersheds with higher than average values of these ecosystem services but without pandas only poorly. Watersheds with pandas do provide higher than average ecosystem services, but watersheds above average for these ecosystem services often lack pandas. Those areas might be potentially important for pandas, but obstacles block their way. We identified conservation areas combining habitats, population, activity range, and higher than average values of these ecosystem services and then proposed new protected areas.Item Open Access Role of mesons in the electromagnetic form factors of the nucleon(Physical Review C - Nuclear Physics, 2010-11-30) Crawford, C; Akdogan, T; Alarcon, R; Bertozzi, W; Booth, E; Botto, T; Calarco, JR; Clasie, B; de Grush, A; Donnelly, TW; Dow, K; Farkhondeh, M; Fatemi, R; Filoti, O; Franklin, W; Gao, H; Geis, E; Gilad, S; Hasell, D; Karpius, P; Kohl, M; Kolster, H; Lee, T; Lomon, E; Maschinot, A; Matthews, J; McIlhany, K; Meitanis, N; Milner, R; Rapaport, J; Redwine, R; Seely, J; Shinozaki, A; Sindile, A; Širca, S; Six, E; Smith, T; Tonguc, B; Tschalaer, C; Tsentalovich, E; Turchinetz, W; Xiao, Y; Xu, W; Zhang, C; Zhou, Z; Ziskin, V; Zwart, TThe roles played by mesons in the electromagnetic form factors of the nucleon are explored using as a basis a model containing vector mesons with coupling to the continuum together with the asymptotic Q2 behavior of perturbative QCD. Specifically, the vector dominance model (GKex) developed by E. L. Lomon is employed, as it is known to be very successful in representing the existing high-quality data published to date. An analysis is made of the experimental uncertainties present when the differences between the GKex model and the data are expanded in orthonormal basis functions. A main motivation for the present study is to provide insight into how the various ingredients in this model yield the measured behavior, including discussions of when dipole form factors are to be expected or not, of which mesons are the major contributors, for instance, at low Q2 or large distances, and of what effects are predicted from coupling to the continuum. Such insights are first discussed in momentum space, followed by an analysis of how different and potentially useful information emerges when both the experimental and theoretical electric form factors are Fourier transformed to coordinate space. While these Fourier transforms should not be interpreted as "charge distributions," nevertheless the roles played by the various mesons, especially those which are dominant at large or small distance scales, can be explored via such experiment-theory comparisons. © 2010 The American Physical Society.