Showing papers by "Louisiana State University published in 2002"

Alu repeats and human genomic diversity

Abstract: During the past 65 million years, Alu elements have propagated to more than one million copies in primate genomes, which has resulted in the generation of a series of Alu subfamilies of different ages. Alu elements affect the genome in several ways, causing insertion mutations, recombination between elements, gene conversion and alterations in gene expression. Alu-insertion polymorphisms are a boon for the study of human population genetics and primate comparative genomics because they are neutral genetic markers of identical descent with known ancestral states.

The Customer Orientation of Service Workers: Personality Trait Effects on Self-and Supervisor Performance Ratings:

Abstract: Prior research indicates that market orientation is associated with positive outcomes for firms. For service organizations, a market orientation is implemented largely through individual service workers. The authors investigate the mediational role of customer orientation in a hierarchical model of the influence of personality traits on self-rated and supervisor-rated performance. The results support a partially mediated hierarchical model. Three basic personality traits (emotional stability, agreeability, and the need for activity) account for 39% of the variance in the customer orientation of employees. In turn, the customer orientation measure and conscientiousness account for 26% of the variance in self-rated performance. The customer orientation measure, along with the direct effects of conscientiousness and agreeability, account for 12% of the variance in manager ratings. The authors discuss the results and their implications for marketing researchers and managers.

Audit‐Firm Tenure and the Quality of Financial Reports*

Abstract: This study examines whether the length of the relationship between a company and an audit firm (audit-firm tenure) is associated with financial-reporting quality. Using two proxies for financial-reporting quality and a sample of Big 6 clients matched on industry and size, we find that relative to medium audit-firm tenures of four to eight years, short audit-firm tenures of two to three years are associated with lower-quality financial reports. In contrast, we find no evidence of reduced financial-reporting quality for longer audit-firm tenures of nine or more years. Overall, our results provide empirical evidence pertinent to the recurring debate regarding mandatory audit-firm rotation — a debate that has, to date, relied on anecdotal evidence and isolated cases.

Grid coverage for surveillance and target location in distributed sensor networks

Abstract: We present novel grid coverage strategies for effective surveillance and target location in distributed sensor networks. We represent the sensor field as a grid (two or three-dimensional) of points (coordinates) and use the term target location to refer to the problem of locating a target at a grid point at any instant in time. We first present an integer linear programming (ILP) solution for minimizing the cost of sensors for complete coverage of the sensor field. We solve the ILP model using a representative public-domain solver and present a divide-and-conquer approach for solving large problem instances. We then use the framework of identifying codes to determine sensor placement for unique target location, We provide coding-theoretic bounds on the number of sensors and present methods for determining their placement in the sensor field. We also show that grid-based sensor placement for single targets provides asymptotically complete (unambiguous) location of multiple targets in the grid.

REVEL: A model for Recent plate velocities from space geodesy

Abstract: [1] We present a new global model for Recent plate velocities, REVEL, describing the relative velocities of 19 plates and continental blocks. The model is derived from publicly available space geodetic (primarily GPS) data for the period 1993–2000. We include an independent and rigorous estimate for GPS velocity uncertainties to assess plate rigidity and propagate these uncertainties to the velocity estimates. The velocity fields for North America, Eurasia, and Antarctica clearly show the effects of glacial isostatic adjustment, and Australia appears to depart from rigid plate behavior in a manner consistent with the mapped intraplate stress field. Two thirds of tested plate pairs agree with the NUVEL-1A geologic (3 Myr average) velocities within uncertainties. Three plate pairs (Caribbean–North America, Caribbean–South America, and North America–Pacific) exhibit significant differences between the geodetic and geologic model that may reflect systematic errors in NUVEL-1A due to the use of seafloor magnetic rate data that do not reflect the full plate rate because of tectonic complexities. Most other differences probably reflect real velocity changes over the last few million years. Several plate pairs (Arabia–Eurasia, Arabia–Nubia, Eurasia–India) move more slowly than the 3 Myr NUVEL-1A average, perhaps reflecting long-term deceleration associated with continental collision. Several other plate pairs, including Nazca–Pacific, Nazca–South America and Nubia–South America, are experiencing slowing that began ∼25 Ma, the beginning of the current phase of Andean crustal shortening.

Mathematical modeling of watershed hydrology.

Abstract: Mathematical modeling of watershed hydrology is employed to address a wide spectrum of environmental and water re- sources problems. A historical perspective of hydrologic modeling is provided, and new developments and challenges in watershed models are discussed. These include data acquisition by remote sensing and space technology, digital terrain and elevation models, chemical tracers, geographic information and data management systems, topographic representation, upscaling of hydrologic conservation equa- tions, spatial variability of hydraulic roughness, infiltration and precipitation, spatial and temporal scaling, model calibration, and linking with water quality models. Model construction, calibration, and data processing have received a great deal of attention, while model validation, error propagation, and analyses of uncertainty, risk, and reliability have not been treated as thoroughly. Finally, some remarks are made regarding the future outlook for watershed hydrology modeling.

Genotype H: a new Amerindian genotype of hepatitis B virus revealed in Central America.

Abstract: The complete genomes were sequenced for ten hepatitis B virus (HBV) strains. Two of them, from Spain and Sweden, were most similar to genotype D, although encoding d specificity. Five of them were from Central America and belonged to genotype F. Two strains from Nicaragua and one from Los Angeles, USA, showed divergences of 3·1–4·1% within the small S gene from genotype F strains and were recognized previously as a divergent clade within genotype F. The complete genomes of the two genotype D strains were found to differ from published genotype D strains by 2·8–4·6%. Their S genes encoded Lys122, Thr127 and Lys160, corresponding to the putative new subtype adw3 within this genotype, previously known to specify ayw2, ayw3 or, rarely, ayw4. The complete genomes of the three divergent strains diverged by 0·8–2·5% from each other, 7·2–10·2% from genotype F strains and 13·2–15·7% from other HBV strains. Since pairwise comparisons of 82 complete HBV genomes of intratypic and intertypic divergences ranged from 0·1 to 7·4% and 6·8 to 17·1%, respectively, the three sequenced strains should represent a new HBV genotype, for which the designation H is proposed. In the polymerase region, the three strains had 16 unique conserved amino acid residues not present in genotype F strains. So far, genotype H has been encountered in Nicaragua, Mexico and California. Phylogenetic analysis of the complete genomes and subgenomes of the three strains showed them clustering with genotype F but forming a separate branch supported by 100% bootstrap. Being most similar to genotype F, known to be an Amerindian genotype, genotype H has most likely split off from genotype F within the New World.

Health Literacy and Cancer Communication

Abstract: Health literacy is increasingly recognized as a critical factor affecting communication across the continuum of cancer care. We reviewed research on health literacy and examined its impact on cancer outcomes and communication. According to the National Adult Literacy Survey (NALS), considered the most accurate portrait of literacy in our society, about one in five American adults may lack the necessary literacy skills to function adequately in our society. As patients, such individuals are at a disadvantage in their capacity to obtain, process, and understand cancer information and services needed to make appropriate health care decisions. Patients with poor health literacy have a complex array of difficulties with written and oral communication that may limit their understanding of cancer screening and of symptoms of cancer, adversely affecting their stage at diagnosis. In addition, these barriers impair communication and discussion about risks and benefits of treatment options, and patient understanding of informed consent for routine procedures and clinical trials. More research is needed to identify successful methods for educating and communicating with patients who have limited health literacy. Based on our own experience, we offer practical communication aids that can help bridge the cancer communication gap.

Double-Blind, Randomized Trial Comparing the Efficacy and Tolerability of Fulvestrant Versus Anastrozole in Postmenopausal Women With Advanced Breast Cancer Progressing on Prior Endocrine Therapy: Results of a North American Trial

Abstract: PURPOSE: To compare the efficacy and tolerability of fulvestrant (formerly ICI 182,780) with anastrozole in the treatment of advanced breast cancer in patients whose disease progresses on prior endocrine treatment. PATIENTS AND METHODS: In this double-blind, double-dummy, parallel-group study, postmenopausal patients were randomized to receive either an intramuscular injection of fulvestrant 250 mg once monthly or a daily oral dose of anastrozole 1 mg. The primary end point was time to progression (TTP). Secondary end points included objective response (OR) rate, duration of response (DOR), and tolerability. RESULTS: Patients (n = 400) were followed for a median period of 16.8 months. Fulvestrant was as effective as anastrozole in terms of TTP (hazard ratio, 0.92; 95.14% confidence interval [CI], 0.74 to 1.14; P = .43); median TTP was 5.4 months with fulvestrant and 3.4 months with anastrozole. OR rates were 17.5% with both treatments. Clinical benefit rates (complete response + partial response + stable ...

Investigation of submarine groundwater discharge

Abstract: Coastal hydrogeologists and oceanographers now recognize the potentially significant contribution that submarine groundwater discharge (SGD) could make to the coastal ocean. SGD may be both volumetrically and chemically important to coastal water and chemical budgets. A worldwide compilation of observed SGD shows that groundwater seepage from the land to the ocean occurs in many environments along the world’s continental margins. Further, SGD has a significant influence on the environmental condition of many nearshore marine environments and provides a strong motivation for improved assessments. Our review reveals a critical lack of data from coastal zones of almost all parts of the world, especially in South America, Africa and parts of Asia, making a comprehensive compilation incomplete. SGD should be paid more attention with regard to water and dissolved material budgets at the local and global scales. SGD intercomparison experiments and coastal typologies (classification) may enable evaluation of the accuracy of the SGD estimates and up-scaling of SGD to a global scale. Copyright  2002 John Wiley & Sons, Ltd.

Molecular systematics of the Eastern Fence Lizard (Sceloporus undulatus): a comparison of Parsimony, Likelihood, and Bayesian approaches.

Abstract: Phylogenetic analysis of large datasets using complex nucleotide substitution models under a maximum likelihood framework can be computationally infeasible, especially when attempting to infer confidence values by way of nonparametric bootstrapping. Recent developments in phylogenetics suggest the computational burden can be reduced by using Bayesian methods of phylogenetic inference. However, few empirical phylogenetic studies exist that explore the efficiency of Bayesian analysis of large datasets. To this end, we conducted an extensive phylogenetic analysis of the wide-ranging and geographically variable Eastern Fence Lizard (Sceloporus undulatus). Maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses were performed on a combined mitochondrial DNA dataset (12S and 16S rRNA, ND1 protein-coding gene, and associated tRNA; 3,688 bp total) for 56 populations of S. undulatus (78 total terminals including other S. undulatus group species and outgroups). Maximum parsimony analysis resulted in numerous equally parsimonious trees (82,646 from equally weighted parsimony and 335 from weighted parsimony). The majority rule consensus tree derived from the Bayesian analysis was topologically identical to the single best phylogeny inferred from the maximum likelihood analysis, but required approximately 80% less computational time. The mtDNA data provide strong support for the monophyly of the S. undulatus group and the paraphyly of "S. undulatus" with respect to S. belli, S. cautus, and S. woodi. Parallel evolution of ecomorphs within "S. undulatus" has masked the actual number of species within this group. This evidence, along with convincing patterns of phylogeographic differentiation suggests "S. undulatus" represents at least four lineages that should be recognized as evolutionary species.

Gene expression profiling of 12633 genes in Alzheimer hippocampal CA1: transcription and neurotrophic factor down-regulation and up-regulation of apoptotic and pro-inflammatory signaling.

Abstract: Alterations in transcription, RNA editing, translation, protein processing, and clearance are a consistent feature of Alzheimer's disease (AD) brain. To extend our initial study (Alzheimer Reports [2000] 3:161-167), RNA samples isolated from control and AD hippocampal cornu ammonis 1 (CA1) were analyzed for 12633 gene and expressed sequence tag (EST) expression levels using DNA microarrays (HG-U95Av2 Genechips; Affymetrix, Santa Clara, CA). Hippocampal CA1 tissues were carefully selected from several hundred potential specimens obtained from domestic and international brain banks. To minimize the effects of individual differences in gene expression, RNA of high spectral quality (A260/280 ≥ 1.9) was pooled from CA1 of six control or six AD subjects. Results were compared as a group; individual gene expression patterns for the most-changed RNA message levels were also profiled. There were no significant differences in age, postmortem interval (mean ≤ 2.1 hr) nor tissue pH (range 6.6–6.9) between the two brain groups. AD tissues were derived from subjects clinically classified as CDR 2-3 (CERAD/NIA). Expression data were analyzed using GeneSpring (Silicon Genetics, Redwood City, CA) and Microarray Data Mining Tool (Affymetrix) software. Compared to controls and 354 background/alignment markers, AD brain showed a generalized depression in brain gene transcription, including decreases in RNA encoding transcription factors (TFs), neurotrophic factors, signaling elements involved in synaptic plasticity such as synaptophysin, metallothionein III, and metal regulatory factor-1. Three- or morefold increases in RNAs encoding DAXX, cPLA2, CDP5, NF-κBp52/p100, FAS, βAPP, DPP1, NFIL6, IL precursor, B94, HB15, COX-2, and CEX-1 signals were strikingly apparent. These data support the hypothesis of widespread transcriptional alterations, misregulation of RNAs involved in metal ion homeostasis, TF signaling deficits, decreases in neurotrophic support and activated apoptotic and neuroinflammatory signaling in moderately affected AD hippocampal CA1. © 2002 Wiley-Liss, Inc.

Relationship quality and relationship context as antecedents of person- and task-focused interpersonal citizenship behavior.

Abstract: A model hypothesizing relationship quality and relationship context as antecedents of two complementary forms of interpersonal citizenship behavior (ICB) was tested. Measures with coworkers as the frame of reference were used to collect data from 273 individuals working in 2 service-oriented organizations. As hypothesized, variables reflecting relationship quality were associated with person-focused ICB, as mediated by empathic concern. Also as hypothesized, a relationship context variable, network centrality, exhibited a direct relationship with task-focused ICB. Unexpectedly, network centrality was directly associated with person-focused ICB, and empathic concern was associated with task-focused ICB. The results are discussed, and implications for research and practice are offered.

Sex, race/ethnicity, socioeconomic status, and BMI in relation to self-perception of overweight

Abstract: Objective: To compare the self-perception of overweight in the study population according to sex, race/ethnicity, and socioeconomic status and to compare the self-perception of overweight among individuals classified as normal weight, overweight, and obese. Research Methods and Procedures: Data from 5440 adults who participated in the 1994 to 1996 Continuing Survey of Food Intakes by Individuals and the Diet and Health Knowledge Survey conducted by the U.S. Department of Agriculture were analyzed. Data for analysis included self-perceived weight status, self-reported weight and height, and demographic and socioeconomic data. Underweight individuals, defined as those with a body mass index <18.5 kg/m2, were excluded from the analysis. Results: Self-perception of overweight was more common in women compared with men and in whites compared with blacks or Hispanics. Both the correct and incorrect perception of overweight was more common in normal weight and overweight white women compared with black women. More overweight and obese white men correctly perceived their overweight status compared with black men. Multiple logistic regression showed that the odds ratio of perceived overweight was significantly higher in women, whites, and individuals with higher body mass index, higher income, and higher education. Discussion: Self-perceived overweight varied by sex, race/ethnicity, and socioeconomic status. Erroneous perception of body weight may have important health and behavioral implications. In particular, a considerable proportion of overweight men may be at risk of obesity if they continue to perceive themselves as having normal weight.

A Critical Evaluation of the Parenting Stress Index-Short Form (PSI-SF) in a Head Start Population

Abstract: Examines psychometric characteristics of the 36-item Parenting Stress Index-Short Form (PSI-SF) in a low-income, predominantly minority population. Relations between the PSI-SF, demographic, and psychosocial factors associated with parenting stress were examined. Internal consistencies for the PSI-SF were very good to excellent. However, confirmatory factor analysis (CFA) indicated that a 3-factor model comprised of Parental Distress, Difficult Child, and Parent-Child Dysfunctional Interaction subscales was only marginally superior to a single-factor model. A series of multiple regression analyses examining the relation of psychosocial and demographic measures to PSI-SF subscales were more supportive of the 3-factor model proposed by Abidin (1995). As anticipated, the PSI-SF Difficult Child subscale was most strongly associated with a measure of child oppositionality, and the Parental Distress subscale was most highly associated with self-reported psychological symptoms and low income. Parent-Child Dysfun...

DNA repair mediated by endonuclease-independent LINE-1 retrotransposition

Abstract: Long interspersed elements (LINE-1s) are abundant retrotransposons in mammalian genomes that probably retrotranspose by target site-primed reverse transcription (TPRT). During TPRT, the LINE-1 endonuclease cleaves genomic DNA, freeing a 3' hydroxyl that serves as a primer for reverse transcription of LINE-1 RNA by LINE-1 reverse transcriptase. The nascent LINE-1 cDNA joins to genomic DNA, generating LINE-1 structural hallmarks such as frequent 5' truncations, a 3' poly(A)+ tail and variable-length target site duplications (TSDs). Here we describe a pathway for LINE-1 retrotransposition in Chinese hamster ovary (CHO) cells that acts independently of endonuclease but is dependent upon reverse transcriptase. We show that endonuclease-independent LINE-1 retrotransposition occurs at near-wildtype levels in two mutant cell lines that are deficient in nonhomologous end-joining (NHEJ). Analysis of the pre- and post-integration sites revealed that endonuclease-independent retrotransposition results in unusual structures because the LINE-1s integrate at atypical target sequences, are truncated predominantly at their 3' ends and lack TSDs. Moreover, two of nine endonuclease-independent retrotranspositions contained cDNA fragments at their 3' ends that are probably derived from the reverse transcription of endogenous mRNA. Thus, our results suggest that LINE-1s can integrate into DNA lesions, resulting in retrotransposon-mediated DNA repair in mammalian cells.

Examining the roles of job involvement and work centrality in predicting organizational citizenship behaviors and job performance

Abstract: A recent meta-analysis by Brown (1996) concluded that job involvement was unrelated to job performance. The present investigation proposed that the null findings reported in this meta-analysis stem from the choice of performance criteria and the use of job involvement measures that are confounded with work centrality in the primary studies included in the meta-analysis. The current study found that job involvement, when assessed with a recently published measure (Paullay et al., 1994), is a significant predictor of supervisor ratings of organizational citizenship behaviors (OCB) and in-role performance, controlling for work centrality and other individual difference variables. Consistent with recent findings, there is evidence that sex moderates some of the job involvement and OCB relationships, with females having a stronger, positive relationship between these constructs than males. Copyright © 2001 John Wiley & Sons, Ltd.

The relation of gender, race and socioeconomic status to obesity and obesity comorbidities in a sample of US adults.

Abstract: OBJECTIVE: To examine the obesity-related chronic diseases in the US adult population according to gender, race and socioeconomic status. METHODS: Data from the 1994-1996 Continuing Survey of Food Intakes by Individuals (1994-1996 CSFII) conducted by the US Department of Agriculture/Agricultural Research Service (USDA/ARS) were used in the analysis. Relevant data included self-reported weight and height, self-reported physician-diagnosed diabetes mellitus, hypertension, heart disease and high serum cholesterol. Analysis was conducted according to gender, race, income level and education level. RESULTS: There was a graded increase in diabetes, hypertension and high serum cholesterol with increasing body weight in nearly all gender, racial and socioeconomic groups. Among the obese individuals, the prevalence of hypertension was higher in black subjects and the prevalence of diabetes, hypertension and heart disease was higher in individuals with lower education compared to their counterparts. The odds of having diabetes, hypertension, heart disease and high serum cholesterol increased with increasing body weight after adjusting for age, gender, race, income, education and smoking. CONCLUSION: Although cross-sectional in nature, our results suggest that the disease burden associated with obesity in the population may be substantial. This burden increases with increasing severity of obesity. Our findings support the current opinion that, although the nature of obesity-related health risks is similar in all populations, the specific level of risk associated with a given level of obesity may be different depending on gender, race and socioeconomic condition.

Increased taxon sampling is advantageous for phylogenetic inference.

Abstract: Until recently, it was believed that complex phylogenies might be extremely difficult to reconstruct due to the phenomenal rate of increase in the number of possible phylogenies as the number of taxa increases. However, Hillis (1996) showed through simulation that, for at least one complex phylogeny of angiosperms with 228 taxa, reconstruction was far more accurate than expected, even with relatively modest amounts of DNA sequence data. This led to a flurry of papers on the subject of taxon sampling and phylogenetic reconstruction, with focus quickly shifting from the question of whether complex phylogenies can be reconstructed to whether and how much an existing phylogeny can be improved through increased taxon sampling (Hillis, 1998; Kim, 1998; Poe, 1998; Poe and Swofford, 1999; Pollock and Bruno, 2000; Rannala et al., 1998; Yang, 1998). Although a statistician might intuitively believe that it is generally better (or at least no worse) to increase the amount of data to resolve a question in statistical inference, the benefits of taxon addition for phylogenetic inference remain controversial. Some researchers have argued that taxon addition can decrease accuracy (Kim, 1996,1998), while others believe that increased sampling improves accuracy (Graybeal, 1998; Hillis, 1996, 1998; Murphy et al., 2001; Poe, 1998; Pollock and Bruno, 2000; Pollock et al., 2000; Soltis et al., 1999). The reasons that different papers come to apparently contradictory conclusions deserve careful consideration. An often cited factor affecting the benefits of taxon addition is the phenomenon of long-branch attraction (LBA). Some phylogenetic methods have a bias toward preferential clustering of long branches, leading to erroneous results when those long branches do not actually represent a monophyletic assemblage (Felsenstein, 1978; Hendy and Penny, 1989). This phenomenon has been cited in favor of increased taxon sampling, since sampling can be designed to break up long branches (Hillis, 1998). However, increased sampling has also been implicated as a potential cause of LBA because addition of a new long branch may wrongly attract a pre-existing long branch that had previously been inferred correctly (Poe and Swofford, 1999; Rannala et al., 1998). LBA may also explain some simulations that have found problems in phylogeny estimation when sampling outside the taxonomic group of interest (but see Pollock and Bruno [2000] for an alternative explanation). Outside sampling in these simulations tended to add long branches, which tended to attract the longest unbroken branch in the group of interest (Hillis, 1998; Rannala et al., 1998). The degree to which LBA is a problem depends greatly on the method of analysis, and LBA is much less of a problem for maximum likelihood (ML) than for parsimony or distance methods (Bruno and Halpern, 1999). A recent paper on the subject of taxon addition (Rosenberg and Kumar, 2001) concludes that increased taxon sampling is of little benefit to phylogenetic inference when compared to increasing sequence length. We disagree with their interpretation and believe that their data support the importance of increased taxon sampling. In addition, some of their data were simulated under extreme conditions (i.e., substitution rates that were very high or low, or sequences that were unreasonably short). Large error values and nonlinear relationships at these extremes make it difficult to interpret effects for the majority of the range, and averaging across the entire range is inappropriate. Moreover, we do not believe that Rosenberg and Kumar (2001) used the most appropriate metric to measure the relative effect of taxon addition. Our reanalysis of their simulated data indicates that increased taxon sampling is highly beneficial for phylogenetic inference.

Global analysis of the Deinococcus radiodurans proteome by using accurate mass tags.

Abstract: Understanding biological systems and the roles of their constituents is facilitated by the ability to make quantitative, sensitive, and comprehensive measurements of how their proteome changes, e.g., in response to environmental perturbations. To this end, we have developed a high-throughput methodology to characterize an organism's dynamic proteome based on the combination of global enzymatic digestion, high-resolution liquid chromatographic separations, and analysis by Fourier transform ion cyclotron resonance mass spectrometry. The peptides produced serve as accurate mass tags for the proteins and have been used to identify with high confidence >61% of the predicted proteome for the ionizing radiation-resistant bacterium Deinococcus radiodurans. This fraction represents the broadest proteome coverage for any organism to date and includes 715 proteins previously annotated as either hypothetical or conserved hypothetical.

Development and Validation of the Food-Craving Inventory

Abstract: Objective: The primary aim of this study was to develop and validate the Food-Craving Inventory (FCI), a self-report measure of specific food cravings. Research Methods and Procedures: In a preliminary study, participants (n = 474) completed the initial version of the FCI. The results from this study were used in developing the revised FCI. Participants (n = 379) completed the revised FCI in the primary study designed to develop a self-report measure of specific food cravings. Results: Common factor analysis yielded four conceptual factors (subscales) that were interpreted as high fats, sweets, carbohydrates/starches, and fast-food fats. Confirmatory factor analysis found that the four factors could be modeled as dimensions (or first-order factors) of a higher order construct—food craving. Test–retest and internal consistency analyses indicated good reliability for the total score and each of the subscales. Subscale scores were compared with scores on the Three Factor Eating Questionnaire and a conceptual measure of food craving. We found support for the content, concurrent, construct, and discriminant validity of the FCI. Discussion: The FCI was found to be a reliable and valid measure of general and specific food cravings. The FCI can be used in research related to overeating and binge eating. Also, it may be useful in treatment studies that target obesity and/or food cravings.

Abrasive wear/corrosion properties and TEM analysis of Al2O3 coatings fabricated using plasma electrolysis

Abstract: Alumina coatings were deposited on Al alloy substrates using an electrolytic plasma technique, based on a dielectric barrier discharge created during anodic oxidation in an aqueous electrolyte. The substrate material (BS Al 6082) was biased anodically with an unbalanced AC high voltage. During processing, a plasma current density of 100 mA/cm2 was used, at which a coating deposition rate of 1.67 μm/min was achieved. Coating abrasive wear and corrosion properties were assessed by conducting dry and wet rubber wheel abrasive tests and potentiodynamic polarization experiments, respectively. X-Ray diffraction (XRD) and transmission electron microscopy (TEM) were used to investigate the coating microstructure, and the coating/substrate interface. The property test results show that the coatings possess excellent abrasive wear and corrosion resistance. XRD analyses indicate that the coatings consist of α- and γ-Al2O3. An amorphous+nanocrystalline inner layer (1.5-μm thick) and a nanocrystalline (50–60 nm) intermediate layer in the coating were observed by TEM. The higher resistance to wear and corrosion can in part be attributed to the presence of these interlayers.

4-1BB promotes the survival of CD8+ T lymphocytes by increasing expression of Bcl-xL and Bfl-1.

Abstract: 4-1BB, a T cell costimulatory receptor, prolongs CD8(+) T cell survival. In these studies, 4-1BB stimulation was shown to increase expression of the antiapoptotic genes bcl-x(L) and bfl-1 via 4-1BB-mediated NF-kappaB activation. This signaling pathway was specifically inhibited by PDTC and was different from the pathways that enhanced CD8(+) T cell proliferation. The results suggest a role for the antiapoptotic activities of Bcl-x(L) and Bfl-1 proteins in 4-1BB-mediated CD8(+) T cell survival in vivo.