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Search Results: 1 - 10 of 221181 matches for " Sandra L. Rodriguez-Reyna "
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Evaluation of Corrosion Behavior of Galvanized Steel Treated with Conventional Conversion Coatings and a Chromate-Free Organic Inhibitor
Laura A. Hernandez-Alvarado,Luis S. Hernandez,Sandra L. Rodriguez-Reyna
International Journal of Corrosion , 2012, DOI: 10.1155/2012/368130
Abstract: Conventional weight loss tests and both DC and AC electrochemical techniques were used to study if an organic inhibitor containing an alkanolamine salt of a polycarboxylic acid can substitute toxic coatings as chromating and certain phosphating procedures in the protection of galvanized steel. The electrolyte used was a 0.5?M aerated NaCl solution. All tests gave concordant results, indicating that the chromate-free organic inhibitor does protect galvanized steel in this environment, even though the provided protection was less than that of the chromate conversion coating. It was observed that, after a moderate initial attack, the corrosion rate diminishes due to the appearance and growth of passivating corrosion products layers, mainly constituted by zinc hydroxychloride and two varieties of zinc hydroxide, among other crystalline compounds. 1. Introduction Conversion coatings are applied to galvanized steel to improve adhesion of additional protective coatings and for corrosion protection of the zinc coating. Phosphate conversion coatings (PCCs) provide adhesion but do not provide substantial corrosion protection. PCCs provide uniform surface texture and increased surface area, and, when used as a base for paint, they promote good adhesion, increase the resistance of the paint to humidity and water soaking, and eventually increase the corrosion resistance of the painted system [1]. Most galvanized steel used in manufacturing industries (car, household appliances, etc.) is phosphate coated and painted. However, some authors [2] have reported the harmful effects of phosphating, mainly those compositions that contain nickel. Chromate conversion coatings (CCCs) for zinc have been the most widely used, as they enhance bare or painted corrosion resistance, improve the adhesion of paint or other organic finishes, and provide the metallic surface with a decorative finish. CCCs are distinguished by their easy application, their applicability to a wide range of alloys and, in many cases, their ability to improve the galvanized corrosion resistance by virtue of a built-in inhibitor reservoir [3]. Although chromate is an excellent corrosion inhibitor, it is highly toxic; it has carcinogenic effects and must be handled and disposed of with extreme care. Therefore, there are severe restrictions on its use. Much effort has been devoted to replace chromate chemicals with safe, nontoxic alternatives that are environmentally benign, and many environmental friendly coating systems are under development [4–7]. However, preparation and corrosion behavior of these
Systemic Lupus Erythematosus
Hiroshi Okamoto,Ricard Cervera,Tatiana S. Rodriguez-Reyna,Hiroyuki Nishimura
Autoimmune Diseases , 2012, DOI: 10.1155/2012/815753
Abstract:
Systemic Lupus Erythematosus
Hiroshi Okamoto,Ricard Cervera,Tatiana S. Rodriguez-Reyna,Hiroyuki Nishimura,Taku Yoshio
Autoimmune Diseases , 2012, DOI: 10.1155/2012/815753
Abstract:
Cellular and Humoral Mechanisms Involved in the Control of Tuberculosis
Joaquin Zu iga,Diana Torres-García,Teresa Santos-Mendoza,Tatiana S. Rodriguez-Reyna,Julio Granados,Edmond J. Yunis
Clinical and Developmental Immunology , 2012, DOI: 10.1155/2012/193923
Abstract: Mycobacterium tuberculosis (Mtb) infection is a major international public health problem. One-third of the world's population is thought to have latent tuberculosis, a condition where individuals are infected by the intracellular bacteria without active disease but are at risk for reactivation, if their immune system fails. Here, we discuss the role of nonspecific inflammatory responses mediated by cytokines and chemokines induced by interaction of innate receptors expressed in macrophages and dendritic cells (DCs). We also review current information regarding the importance of several cytokines including IL-17/IL-23 in the development of protective cellular and antibody-mediated protective responses against Mtb and their influence in containment of the infection. Finally, in this paper, emphasis is placed on the mechanisms of failure of Mtb control, including the immune dysregulation induced by the treatment with biological drugs in different autoimmune diseases. Further functional studies, focused on the mechanisms involved in the early host-Mtb interactions and the interplay between host innate and acquired immunity against Mtb, may be helpful to improve the understanding of protective responses in the lung and in the development of novel therapeutic and prophylactic tools in TB.
Transcription Factor-MicroRNA-Target Gene Networks Associated with Ovarian Cancer Survival and Recurrence
Kristin R. Delfino, Sandra L. Rodriguez-Zas
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0058608
Abstract: The identification of reliable transcriptome biomarkers requires the simultaneous consideration of regulatory and target elements including microRNAs (miRNAs), transcription factors (TFs), and target genes. A novel approach that integrates multivariate survival analysis, feature selection, and regulatory network visualization was used to identify reliable biomarkers of ovarian cancer survival and recurrence. Expression profiles of 799 miRNAs, 17,814 TFs and target genes and cohort clinical records on 272 patients diagnosed with ovarian cancer were simultaneously considered and results were validated on an independent group of 146 patients. Three miRNAs (hsa-miR-16, hsa-miR-22*, and ebv-miR-BHRF1-2*) were associated with both ovarian cancer survival and recurrence and 27 miRNAs were associated with either one hazard. Two miRNAs (hsa-miR-521 and hsa-miR-497) were cohort-dependent, while 28 were cohort-independent. This study confirmed 19 miRNAs previously associated with ovarian cancer and identified two miRNAs that have previously been associated with other cancer types. In total, the expression of 838 and 734 target genes and 12 and eight TFs were associated (FDR-adjusted P-value <0.05) with ovarian cancer survival and recurrence, respectively. Functional analysis highlighted the association between cellular and nucleotide metabolic processes and ovarian cancer. The more direct connections and higher centrality of the miRNAs, TFs and target genes in the survival network studied suggest that network-based approaches to prognosticate or predict ovarian cancer survival may be more effective than those for ovarian cancer recurrence. This study demonstrated the feasibility to infer reliable miRNA-TF-target gene networks associated with survival and recurrence of ovarian cancer based on the simultaneous analysis of co-expression profiles and consideration of the clinical characteristics of the patients.
A Novel Dynamic Impact Approach (DIA) for Functional Analysis of Time-Course Omics Studies: Validation Using the Bovine Mammary Transcriptome
Massimo Bionaz, Kathiravan Periasamy, Sandra L. Rodriguez-Zas, Walter L. Hurley, Juan J. Loor
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0032455
Abstract: The overrepresented approach (ORA) is the most widely-accepted method for functional analysis of microarray datasets. The ORA is computationally-efficient and robust; however, it suffers from the inability of comparing results from multiple gene lists particularly with time-course experiments or those involving multiple treatments. To overcome such limitation a novel method termed Dynamic Impact Approach (DIA) is proposed. The DIA provides an estimate of the biological impact of the experimental conditions and the direction of the impact. The impact is obtained by combining the proportion of differentially expressed genes (DEG) with the log2 mean fold change and mean –log P-value of genes associated with the biological term. The direction of the impact is calculated as the difference of the impact of up-regulated DEG and down-regulated DEG associated with the biological term. The DIA was validated using microarray data from a time-course experiment of bovine mammary gland across the lactation cycle. Several annotation databases were analyzed with DIA and compared to the same analysis performed by the ORA. The DIA highlighted that during lactation both BTA6 and BTA14 were the most impacted chromosomes; among Uniprot tissues those related with lactating mammary gland were the most positively-impacted; within KEGG pathways ‘Galactose metabolism’ and several metabolism categories related to lipid synthesis were among the most impacted and induced; within Gene Ontology “lactose biosynthesis” among Biological processes and “Lactose synthase activity” and “Stearoyl-CoA 9-desaturase activity” among Molecular processes were the most impacted and induced. With the exception of the terms ‘Milk’, ‘Milk protein’ and ‘Mammary gland’ among Uniprot tissues and SP_PIR_Keyword, the use of ORA failed to capture as significantly-enriched (i.e., biologically relevant) any term known to be associated with lactating mammary gland. Results indicate the DIA is a biologically-sound approach for analysis of time-course experiments. This tool represents an alternative to ORA for functional analysis.
Transcriptomic Profiling of Central Nervous System Regions in Three Species of Honey Bee during Dance Communication Behavior
Moushumi Sen Sarma, Sandra L. Rodriguez-Zas, Feng Hong, Sheng Zhong, Gene E. Robinson
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006408
Abstract: Background We conducted a large-scale transcriptomic profiling of selected regions of the central nervous system (CNS) across three species of honey bees, in foragers that were performing dance behavior to communicate to their nestmates the location, direction and profitability of an attractive floral resource. We used microarrays to measure gene expression in bees from Apis mellifera, dorsata and florea, species that share major traits unique to the genus and also show striking differences in biology and dance communication. The goals of this study were to determine the extent of regional specialization in gene expression and to explore the molecular basis of dance communication. Principal Findings This “snapshot” of the honey bee CNS during dance behavior provides strong evidence for both species-consistent and species-specific differences in gene expression. Gene expression profiles in the mushroom bodies consistently showed the biggest differences relative to the other CNS regions. There were strong similarities in gene expression between the central brain and the second thoracic ganglion across all three species; many of the genes were related to metabolism and energy production. We also obtained gene expression differences between CNS regions that varied by species: A. mellifera differed the most, while dorsata and florea tended to be more similar. Significance Species differences in gene expression perhaps mirror known differences in nesting habit, ecology and dance behavior between mellifera, florea and dorsata. Species-specific differences in gene expression in selected CNS regions that relate to synaptic activity and motor control provide particularly attractive candidate genes to explain the differences in dance behavior exhibited by these three honey bee species. Similarities between central brain and thoracic ganglion provide a unique perspective on the potential coupling of these two motor-related regions during dance behavior and perhaps provide a snapshot of the energy intensive process of dance output generation. Mushroom body results reflect known roles for this region in the regulation of learning, memory and rhythmic behavior.
Transcriptomics Comparison between Porcine Adipose and Bone Marrow Mesenchymal Stem Cells during In Vitro Osteogenic and Adipogenic Differentiation
Elisa Monaco, Massimo Bionaz, Sandra Rodriguez-Zas, Walter L. Hurley, Matthew B. Wheeler
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0032481
Abstract: Bone-marrow mesenchymal stem cells (BMSC) are considered the gold standard for use in tissue regeneration among mesenchymal stem cells (MSC). The abundance and ease of harvest make the adipose-derived stem cells (ASC) an attractive alternative to BMSC. The aim of the present study was to compare the transcriptome of ASC and BMSC, respectively isolated from subcutaneous adipose tissue and femur of 3 adult pigs, during in vitro osteogenic and adipogenic differentiation for up to four weeks. At 0, 2, 7, and 21 days of differentiation RNA was extracted for microarray analysis. A False Discovery Rate ≤0.05 for overall interactions effect and P<0.001 between comparisons were used to determine differentially expressed genes (DEG). Ingenuity Pathway Analysis and DAVID performed the functional analysis of the DEG. Functional analysis of highest expressed genes in MSC and genes more expressed in MSC vs. fully differentiated tissues indicated low immunity and high angiogenic capacity. Only 64 genes were differentially expressed between ASC and BMSC before differentiation. The functional analysis uncovered a potential larger angiogenic, osteogenic, migration, and neurogenic capacity in BMSC and myogenic capacity in ASC. Less than 200 DEG were uncovered between ASC and BMSC during differentiation. Functional analysis also revealed an overall greater lipid metabolism in ASC, while BMSC had a greater cell growth and proliferation. The time course transcriptomic comparison between differentiation types uncovered <500 DEG necessary to determine cell fate. The functional analysis indicated that osteogenesis had a larger cell proliferation and cytoskeleton organization with a crucial role of G-proteins. Adipogenesis was driven by PPAR signaling and had greater angiogenesis, lipid metabolism, migration, and tumorigenesis capacity. Overall the data indicated that the transcriptome of the two MSC is relatively similar across the conditions studied. In addition, functional analysis data might indicate differences in therapeutic application.
Fine-mapping of a QTL influencing pork tenderness on porcine chromosome 2
Stacey N Meyers, Sandra L Rodriguez-Zas, Jonathan E Beever
BMC Genetics , 2007, DOI: 10.1186/1471-2156-8-69
Abstract: Recent advances in porcine genome resources, including high-resolution radiation hybrid and bacterial artificial chromosome (BAC) physical maps, were utilized for development of novel informative markers. Marker density in the ~30-Mb region surrounding the most likely QTL position was increased by addition of eighteen new microsatellite markers, including nine publicly-available and nine novel markers. Two newly-developed markers were derived from a porcine BAC clone containing the CAST gene. Refinement of the QTL position was achieved through linkage and haplotype analyses. Within-family linkage analyses revealed at least two families segregating for a highly-significant QTL in strong positional agreement with CAST markers. A combined analysis of these two families yielded QTL intervals of 36 cM and 7 cM for Instron shear force and taste panel tenderness, respectively, while haplotype analyses suggested further refinement to a 1.8 cM interval containing CAST markers. The presence of additional tenderness QTL on SSC2q was also suggested.These results reinforce CAST as a strong positional candidate. Further analysis of CAST molecular variation within the IMQP F1 boars should enhance understanding of the molecular basis of pork tenderness, and thus allow for genetic improvement of pork products. Furthermore, additional resources have been generated for the targeted investigation of other putative QTL on SSC2q, which may lead to further advancements in pork quality.A major objective of the swine industry is to supply high-quality, nutritious pork for consumers. To meet consumer demand, it is necessary for animal producers to recognize and understand both the genetic and environmental factors influencing pork quality. The genetic component of meat quality is complex, i.e. many economically important quality traits, such as color, flavor, juiciness, fat content and tenderness, are controlled by several genes throughout the genome referred to as quantitative trait loci (Q
Meta-analysis of genome-wide expression patterns associated with behavioral maturation in honey bees
Heather A Adams, Bruce R Southey, Gene E Robinson, Sandra L Rodriguez-Zas
BMC Genomics , 2008, DOI: 10.1186/1471-2164-9-503
Abstract: Comparison of lists of genes with significant differential expression across studies failed to identify genes with consistent patterns of expression that were below the selected significance threshold, or identified genes with significant yet inconsistent patterns. The meta-analytical framework supported the identification of genes with consistent overall expression patterns and eliminated genes that exhibited contradictory expression patterns across studies. Sample-level meta-analysis of normalized gene-expression can detect more differentially expressed genes than the study-level meta-analysis of estimates for genes that were well described by similar model parameter estimates across studies and had small variation across studies. Furthermore, study-level meta-analysis was well suited for genes that exhibit consistent patterns across studies, genes that had substantial variation across studies, and genes that did not conform to the assumptions of the sample-level meta-analysis. Meta-analyses confirmed previously reported genes and helped identify genes (e.g. Tomosyn, Chitinase 5, Adar, Innexin 2, Transferrin 1, Sick, Oatp26F) and Gene Ontology categories (e.g. purine nucleotide binding) not previously associated with maturation in honey bees.This study demonstrated that a combination of meta-analytical approaches best addresses the highly dimensional nature of genome-wide microarray studies. As expected, the integration of gene expression information from microarray studies using meta-analysis enhanced the characterization of the transcriptome of complex biological processes.One goal of microarray studies is to identify transcripts that are regulated similarly across a variety of contexts. The integration of gene expression information from multiple microarray studies can enhance the characterization of gene expression profiles that are consistently expressed across experiments. The across-study integration of information can support a more accurate identification
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