Science.gov

Sample records for deleterious materials

  1. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  2. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  3. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  4. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  5. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Added poisonous or deleterious substances. 109.6...-PACKAGING MATERIAL General Provisions § 109.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  6. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Added poisonous or deleterious substances. 109.6...-PACKAGING MATERIAL General Provisions § 109.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  7. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Added poisonous or deleterious substances. 109.6...-PACKAGING MATERIAL General Provisions § 109.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  8. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  9. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Added poisonous or deleterious substances. 109.6...-PACKAGING MATERIAL General Provisions § 109.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  10. Deleterious background selection with recombination

    SciTech Connect

    Hudson, R.R.; Kaplan, N.L.

    1995-12-01

    An analytic expression for the expected nucleotide diversity is obtained for a neutral locus in a region with deleterious mutation and recombination. Our analytic results are used to predict levels of variation for the entire third chromosome of Drosophila melanogaster. The predictions are consistent with the low levels of variation that have been observed at loci near the centromeres of the third chromosome of D. melanogaster. However, the low levels of variation observed near the tips of this chromosome are not predicted using currently available estimates of the deleterious mutation rate and of selection coefficients. If considerably smaller selection coefficients are assumed, the low observed levels of variation at the tips of the third chromosome are consistent with the background selection model. 33 refs., 4 figs., 1 tab.

  11. Limited dispersal, deleterious mutations and the evolution of sex

    SciTech Connect

    Peck, J.R.

    1996-03-01

    This study presents a mathematical model that allows for some offspring to be dispersed at random, while others stay close to their mothers. A single genetic locus is assumed to control fertility, and this locus is subject to the occurrence of deletions mutations. It is shown that, at equilibrium, the frequency of deleterious mutations in the population is inversely related to the rate of dispersal. The results also show that sexual reproduction can lead to a decrease in the equilibrium frequency of deleterious mutations. The reason for this relationship is that sex involves the dispersal of genetic material, and thus, like the dispersal of offspring, sex enhances competition among adults. The model is described using the example of a hermaphroditic plant population. However, the results should apply to animal populations as well. 36 refs., 1 fig.

  12. Validation of Deleterious Mutations in Vorderwald Cattle

    PubMed Central

    Reinartz, Sina; Distl, Ottmar

    2016-01-01

    In Montbéliarde cattle two candidate mutations on bovine chromosomes 19 and 29 responsible for embryonic lethality have been detected. Montbéliarde bulls have been introduced into Vorderwald cattle to improve milk and fattening performance. Due to the small population size of Vorderwald cattle and the wide use of a few Montbéliarde bulls through artificial insemination, inbreeding on Montbéliarde bulls in later generations was increasing. Therefore, we genotyped an aborted fetus which was inbred on Montbéliarde as well as Vorderwald x Montbéliarde crossbred bulls for both deleterious mutations. The abortion was observed in an experimental herd of Vorderwald cattle. The objectives of the present study were to prove if one or both lethal mutations may be assumed to have caused this abortion and to show whether these deleterious mutations have been introduced into the Vorderwald cattle population through Montbéliarde bulls. The aborted fetus was homozygous for the SLC37A2:g.28879810C>T mutation (ss2019324563) on BTA29 and both parents as well as the paternal and maternal grandsire were heterozygous for this mutation. In addition, the parents and the paternal grandsire were carriers of the MH2-haplotype linked with the T-allele of the SLC37A2:g.28879810C>T mutation. For the SHBG:g.27956790C>T mutation (rs38377500) on BTA19 (MH1), the aborted fetus and its sire were heterozygous. Among all further 341 Vorderwald cattle genotyped we found 27 SLC37A2:g.28879810C>T heterozygous animals resulting in an allele frequency of 0.0396. Among the 120 male Vorderwald cattle, there were 12 heterozygous with an allele frequency of 0.05. The SLC37A2:g.28879810C>T mutation could not be found in further nine cattle breeds nor in Vorderwald cattle with contributions from Ayrshire bulls. In 69 Vorderwald cattle without genes from Montbéliarde bulls the mutated allele of SLC37A2:g.28879810C>T could not be detected. The SHBG:g.27956790C>T mutation appeared unlikely to be responsible

  13. Deleterious mutation accumulation and the regeneration of genetic resources

    PubMed Central

    Schoen, Daniel J.; David, Jacques L.; Bataillon, Thomas M.

    1998-01-01

    The accumulation of mildly deleterious mutations accompanying recurrent regeneration of plant germ plasm was modeled under regeneration conditions characterized by different amounts of selection and genetic drift. Under some regeneration conditions (sample sizes ≥75 individuals and bulk harvesting of seed) mutation accumulation was negligible, but under others (sample sizes <75 individuals or equalization of seed production by individual plants) mutation numbers per genome increased significantly during 25–50 cycles of regeneration. When mutations also are assumed to occur (at elevated rates) during seed storage, significant mutation accumulation and fitness decline occurred in 10 or fewer cycles of regeneration regardless of the regeneration conditions. Calculations also were performed to determine the numbers of deleterious mutations introduced and remaining in the genome of an existing variety after hybridization with a genetic resource and subsequent backcrossing. The results suggest that mutation accumulation has the potential to reduce the viability of materials held in germ plasm collections and to offset gains expected by the introduction of particular genes of interest from genetic resources. PMID:9419386

  14. The Role of Deleterious Substitutions in Crop Genomes

    PubMed Central

    Kono, Thomas J. Y.; Fu, Fengli; Mohammadi, Mohsen; Hoffman, Paul J.; Liu, Chaochih; Stupar, Robert M.; Smith, Kevin P.; Tiffin, Peter; Fay, Justin C.; Morrell, Peter L.

    2016-01-01

    Populations continually incur new mutations with fitness effects ranging from lethal to adaptive. While the distribution of fitness effects of new mutations is not directly observable, many mutations likely either have no effect on organismal fitness or are deleterious. Historically, it has been hypothesized that a population may carry many mildly deleterious variants as segregating variation, which reduces the mean absolute fitness of the population. Recent advances in sequencing technology and sequence conservation-based metrics for inferring the functional effect of a variant permit examination of the persistence of deleterious variants in populations. The issue of segregating deleterious variation is particularly important for crop improvement, because the demographic history of domestication and breeding allows deleterious variants to persist and reach moderate frequency, potentially reducing crop productivity. In this study, we use exome resequencing of 15 barley accessions and genome resequencing of 8 soybean accessions to investigate the prevalence of deleterious single nucleotide polymorphisms (SNPs) in the protein-coding regions of the genomes of two crops. We conclude that individual cultivars carry hundreds of deleterious SNPs on average, and that nonsense variants make up a minority of deleterious SNPs. Our approach identifies known phenotype-altering variants as deleterious more frequently than the genome-wide average, suggesting that putatively deleterious variants are likely to affect phenotypic variation. We also report the implementation of a SNP annotation tool BAD_Mutations that makes use of a likelihood ratio test based on alignment of all currently publicly available Angiosperm genomes. PMID:27301592

  15. Obstruction of adaptation in diploids by recessive, strongly deleterious alleles.

    PubMed

    Assaf, Zoe June; Petrov, Dmitri A; Blundell, Jamie R

    2015-05-19

    Recessive deleterious mutations are common, causing many genetic disorders in humans and producing inbreeding depression in the majority of sexually reproducing diploids. The abundance of recessive deleterious mutations in natural populations suggests they are likely to be present on a chromosome when a new adaptive mutation occurs, yet the dynamics of recessive deleterious hitchhikers and their impact on adaptation remains poorly understood. Here we model how a recessive deleterious mutation impacts the fate of a genetically linked dominant beneficial mutation. The frequency trajectory of the adaptive mutation in this case is dramatically altered and results in what we have termed a "staggered sweep." It is named for its three-phased trajectory: (i) Initially, the two linked mutations have a selective advantage while rare and will increase in frequency together, then (ii), at higher frequencies, the recessive hitchhiker is exposed to selection and can cause a balanced state via heterozygote advantage (the staggered phase), and (iii) finally, if recombination unlinks the two mutations, then the beneficial mutation can complete the sweep to fixation. Using both analytics and simulations, we show that strongly deleterious recessive mutations can substantially decrease the probability of fixation for nearby beneficial mutations, thus creating zones in the genome where adaptation is suppressed. These mutations can also significantly prolong the number of generations a beneficial mutation takes to sweep to fixation, and cause the genomic signature of selection to resemble that of soft or partial sweeps. We show that recessive deleterious variation could impact adaptation in humans and Drosophila.

  16. Deleterious mutations and selection for sex in finite diploid populations.

    PubMed

    Roze, Denis; Michod, Richard E

    2010-04-01

    In diploid populations, indirect benefits of sex may stem from segregation and recombination. Although it has been recognized that finite population size is an important component of selection for recombination, its effects on selection for segregation have been somewhat less studied. In this article, we develop analytical two- and three-locus models to study the effect of recurrent deleterious mutations on a modifier gene increasing sex, in a finite diploid population. The model also incorporates effects of mitotic recombination, causing loss of heterozygosity (LOH). Predictions are tested using multilocus simulations representing deleterious mutations occurring at a large number of loci. The model and simulations show that excess of heterozygosity generated by finite population size is an important component of selection for sex, favoring segregation when deleterious alleles are nearly additive to dominant. Furthermore, sex tends to break correlations in homozygosity among selected loci, which disfavors sex when deleterious alleles are either recessive or dominant. As a result, we find that it is difficult to maintain costly sex when deleterious alleles are recessive. LOH tends to favor sex when deleterious mutations are recessive, but the effect is relatively weak for rates of LOH corresponding to current estimates (of the order 10(-4)-10(-5)).

  17. Efficient purging of deleterious mutations in plants with haploid selfing.

    PubMed

    Szövényi, Péter; Devos, Nicolas; Weston, David J; Yang, Xiaohan; Hock, Zsófia; Shaw, Jonathan A; Shimizu, Kentaro K; McDaniel, Stuart F; Wagner, Andreas

    2014-05-14

    In diploid organisms, selfing reduces the efficiency of selection in removing deleterious mutations from a population. This need not be the case for all organisms. Some plants, for example, undergo an extreme form of selfing known as intragametophytic selfing, which immediately exposes all recessive deleterious mutations in a parental genome to selective purging. Here, we ask how effectively deleterious mutations are removed from such plants. Specifically, we study the extent to which deleterious mutations accumulate in a predominantly selfing and a predominantly outcrossing pair of moss species, using genome-wide transcriptome data. We find that the selfing species purge significantly more nonsynonymous mutations, as well as a greater proportion of radical amino acid changes which alter physicochemical properties of amino acids. Moreover, their purging of deleterious mutation is especially strong in conserved regions of protein-coding genes. Our observations show that selfing need not impede but can even accelerate the removal of deleterious mutations, and do so on a genome-wide scale.

  18. Efficient Purging of Deleterious Mutations in Plants with Haploid Selfing

    PubMed Central

    Szövényi, Péter; Devos, Nicolas; Weston, David J.; Yang, Xiaohan; Hock, Zsófia; Shaw, Jonathan A.; Shimizu, Kentaro K.; McDaniel, Stuart F.; Wagner, Andreas

    2014-01-01

    In diploid organisms, selfing reduces the efficiency of selection in removing deleterious mutations from a population. This need not be the case for all organisms. Some plants, for example, undergo an extreme form of selfing known as intragametophytic selfing, which immediately exposes all recessive deleterious mutations in a parental genome to selective purging. Here, we ask how effectively deleterious mutations are removed from such plants. Specifically, we study the extent to which deleterious mutations accumulate in a predominantly selfing and a predominantly outcrossing pair of moss species, using genome-wide transcriptome data. We find that the selfing species purge significantly more nonsynonymous mutations, as well as a greater proportion of radical amino acid changes which alter physicochemical properties of amino acids. Moreover, their purging of deleterious mutation is especially strong in conserved regions of protein-coding genes. Our observations show that selfing need not impede but can even accelerate the removal of deleterious mutations, and do so on a genome-wide scale. PMID:24879432

  19. Efficient purging of deleterious mutations in plants with haploid selfing

    SciTech Connect

    Szovenyi, Peter; Shaw, Jon; Yang, Xiaohan; Devos, Nicolas

    2014-05-30

    In diploid organisms, selfing reduces the efficiency of selection in removing deleterious mutations from a population. This need not be the case for all organisms. Some plants, for example, undergo an extreme form of selfing known as intragametophytic selfing, which immediately exposes all recessive deleterious mutations in a parental genome to selective purging. Here we ask how effectively deleterious mutations are removed from such plants. Specifically, we study the extent to which deleterious mutations accumulate in a predominantly selfing and a predominantly outcrossing pair of moss species, using genome-wide transcriptome data. We find that the selfing species purge significantly more non-synonymous mutations, as well as a greater proportion of radical amino acid changes which alter physicochemical properties of amino acids. Moreover, their purging of deleterious mutation is especially strong in conserved regions of protein-coding genes. Our observations show that selfing need not impede but can even accelerate the removal of deleterious mutations, and do so on a genome-wide scale.

  20. Deleterious oral habits in children with hearing impairment

    PubMed Central

    SUHANI, RALUCA DIANA; SUHANI, MIHAI FLAVIU; MUNTEAN, ALEXANDRINA; MESAROS, MICHAELA; BADEA, MINDRA EUGENIA

    2015-01-01

    Background and aims Deleterious oral habits represent a serious public health issue. The information available about this problem in children with hearing impairment is insufficient. The purpose of this study was to investigate the prevalence of deleterious oral habits among children with hearing impairment and comparing results against children without hearing impairment. Method This epidemiological study was carried out in a sample size of 315 children. We used a random sampling technique that included 150 children with hearing impairment and 165 without hearing impairment. All subjects were submitted to a clinical examination. The parents/legal guardians were asked to complete a questionnaire regarding the deleterious habits of their children. Results The data collected indicated a higher prevalence of deleterious oral habits among children with hearing impairment: 53.3% as opposed to 40.6% among children without hearing impairment. There was a higher incidence of malocclusion in children with hearing impairment (79.3%) compared to children without hearing impairment (57%). Conclusions This study highlighted the need to establish protocols for preventive orthodontic treatment at an early age, in order to reduce the deleterious oral habits and prevent malocclusion. Dental institutions/clinicians need to implement oral care programs including proper oral education aiming to promote oral health. PMID:26609277

  1. Deleterious mutation accumulation in asexual Timema stick insects.

    PubMed

    Henry, Lee; Schwander, Tanja; Crespi, Bernard J

    2012-01-01

    Sexual reproduction is extremely widespread in spite of its presumed costs relative to asexual reproduction, indicating that it must provide significant advantages. One postulated benefit of sex and recombination is that they facilitate the purging of mildly deleterious mutations, which would accumulate in asexual lineages and contribute to their short evolutionary life span. To test this prediction, we estimated the accumulation rate of coding (nonsynonymous) mutations, which are expected to be deleterious, in parts of one mitochondrial (COI) and two nuclear (Actin and Hsp70) genes in six independently derived asexual lineages and related sexual species of Timema stick insects. We found signatures of increased coding mutation accumulation in all six asexual Timema and for each of the three analyzed genes, with 3.6- to 13.4-fold higher rates in the asexuals as compared with the sexuals. In addition, because coding mutations in the asexuals often resulted in considerable hydrophobicity changes at the concerned amino acid positions, coding mutations in the asexuals are likely associated with more strongly deleterious effects than in the sexuals. Our results demonstrate that deleterious mutation accumulation can differentially affect sexual and asexual lineages and support the idea that deleterious mutation accumulation plays an important role in limiting the long-term persistence of all-female lineages.

  2. Nonequilibrium model for estimating parameters of deleterious mutations

    NASA Astrophysics Data System (ADS)

    Gordo, Isabel; Dionisio, Francisco

    2005-03-01

    Deleterious mutations are of extreme evolutionary importance because, even though they are eliminated by natural selection, their continuous pressure creates a pool of variability in natural populations. They are of potential relevance for the existence of several features in evolution, such as sexual reproduction, and pose a risk to small asexual populations. Despite their extreme importance, the deleterious mutation rate and the effects of each mutation on fitness are poorly known quantities. Here we analyze a simple model that can be applied to simple experiments, in microorganisms, aiming at the quantification of these values.

  3. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Added poisonous or deleterious substances. 109.6 Section 109.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION UNAVOIDABLE CONTAMINANTS IN FOOD FOR HUMAN CONSUMPTION AND...

  4. Prevention of deleterious deposits in a coal liquefaction system

    DOEpatents

    Carr, Norman L.; Prudich, Michael E.; King, Jr., William E.; Moon, William G.

    1984-07-03

    A process for preventing the formation of deleterious coke deposits on the walls of coal liquefaction reactor vessels involves passing hydrogen and a feed slurry comprising feed coal and recycle liquid solvent to a coal liquefaction reaction zone while imparting a critical mixing energy of at least 3500 ergs per cubic centimeter of reaction zone volume per second to the reacting slurry.

  5. Effect of deleterious mutations on life span in Drosophila melanogaster.

    PubMed

    Gong, Yi; Thompson, James N; Woodruff, R C

    2006-12-01

    Evolutionary theories of aging assume that the accumulation of deleterious mutations will reduce life span. We tested this assumption in Drosophila melanogaster by a newly designed mating scheme, in which mutations accumulate on the Binscy balancer X chromosome in heterozygous females in the absence of selection and recombination. We found that the life span of Binscy/RY(L) males from this cross decreased faster than the life span of their sibling controls over time in two of three runs, and that there was an age-specific increase in mortality in the Binscy/RY(L) males with time in one of three runs. Therefore, the accumulation of deleterious mutations can decrease life span by increasing fragility and can cause age-specific changes in mortality. These results support the evolutionary theory of aging.

  6. Amino acid composition of proteins reduces deleterious impact of mutations

    PubMed Central

    Hormoz, Sahand

    2013-01-01

    The evolutionary origin of amino acid occurrence frequencies in proteins (composition) is not yet fully understood. We suggest that protein composition works alongside the genetic code to minimize impact of mutations on protein structure. First, we propose a novel method for estimating thermodynamic stability of proteins whose sequence is constrained to a fixed composition. Second, we quantify the average deleterious impact of substituting one amino acid with another. Natural proteome compositions are special in at least two ways: 1) Natural compositions do not generate more stable proteins than the average random composition, however, they result in proteins that are less susceptible to damage from mutations. 2) Natural proteome compositions that result in more stable proteins (i.e. those of thermophiles) are also tuned to have a higher tolerance for mutations. This is consistent with the observation that environmental factors selecting for more stable proteins also enhance the deleterious impact of mutations. PMID:24108121

  7. Prevalence of deleterious ATM germline mutations in gastric cancer patients.

    PubMed

    Huang, Dong-Sheng; Tao, Hou-Quan; He, Xu-Jun; Long, Ming; Yu, Sheng; Xia, Ying-Jie; Wei, Zhang; Xiong, Zikai; Jones, Sian; He, Yiping; Yan, Hai; Wang, Xiaoyue

    2015-12-01

    Besides CDH1, few hereditary gastric cancer predisposition genes have been previously reported. In this study, we discovered two germline ATM mutations (p.Y1203fs and p.N1223S) in a Chinese family with a history of gastric cancer by screening 83 cancer susceptibility genes. Using a published exome sequencing dataset, we found deleterious germline mutations of ATM in 2.7% of 335 gastric cancer patients of different ethnic origins. The frequency of deleterious ATM mutations in gastric cancer patients is significantly higher than that in general population (p=0.0000435), suggesting an association of ATM mutations with gastric cancer predisposition. We also observed biallelic inactivation of ATM in tumors of two gastric cancer patients. Further evaluation of ATM mutations in hereditary gastric cancer will facilitate genetic testing and risk assessment.

  8. RNA chaperones buffer deleterious mutations in E. coli

    PubMed Central

    Rudan, Marina; Schneider, Dominique; Warnecke, Tobias; Krisko, Anita

    2015-01-01

    Both proteins and RNAs can misfold into non-functional conformations. Protein chaperones promote native folding of nascent polypeptides and refolding of misfolded species, thereby buffering mutations that compromise protein structure and function. Here, we show that RNA chaperones can also act as mutation buffers that enhance organismal fitness. Using competition assays, we demonstrate that overexpression of select RNA chaperones, including three DEAD box RNA helicases (DBRHs) (CsdA, SrmB, RhlB) and the cold shock protein CspA, improves fitness of two independently evolved Escherichia coli mutator strains that have accumulated deleterious mutations during short- and long-term laboratory evolution. We identify strain-specific mutations that are deleterious and subject to buffering when introduced individually into the ancestral genotype. For DBRHs, we show that buffering requires helicase activity, implicating RNA structural remodelling in the buffering process. Our results suggest that RNA chaperones might play a fundamental role in RNA evolution and evolvability. DOI: http://dx.doi.org/10.7554/eLife.04745.001 PMID:25806682

  9. A bird's eye view of a deleterious recessive allele.

    PubMed

    Ekblom, Robert

    2016-07-01

    In the endangered Scottish chough (Pyrrhocorax pyrrhocorax) population, a lethal blindness syndrome is found to be caused by a deleterious recessive allele. Photo: Gordon Yates. In Focus: Trask, A.E., Bignal, E.M., McCracken, D.I., Monaghan, P., Piertney, S.B. & Reid, J.M. (2016) Evidence of the phenotypic expression of a lethal recessive allele under inbreeding in a wild population of conservation concern. Journal of Animal Ecology, 85, 879-891. In this issue of Journal of Animal Ecology, Trask et al. () report on a strange, lethal, blindness that regularly affects chicks of an endangered bird population. The authors show that the inheritance mode of this blindness disease precisely matches the expectations of a recessive deleterious mutation. Intriguingly, there is also an indication that the disease-causing variant might be maintained in the population by balancing selection, due to a selective advantage for heterozygotes. Could this finding have consequences for conservation actions implemented for the population?

  10. Quantifying genetic diversity under a broad spectrum of deleterious mutations

    NASA Astrophysics Data System (ADS)

    Good, Benjamin; Desai, Michael

    2013-03-01

    Recent studies have shown that selection against deleterious mutations may play a major role in shaping observed patterns of sequence variation in natural populations. However, our understanding of these patterns remains limited, since selection creates correlations along the genome that are difficult to disentangle from each other. Previous theoretical work has focused on the qualitative effects of selection on sequence diversity, using simplified models in which all selected mutations have the same fitness cost. Yet is known that deleterious mutations follow a wide distribution in most organisms, so it is necessary to extend our theoretical predictions to this more general case before we can make quantitative connections with existing data. The evolutionary dynamics of this regime are complicated: extant mutant lineages represent large, correlated fluctuations away from the background expectation, which hinders efforts to apply existing methods based on deterministic or ``mean-field'' approximations. Here, we will describe recent progress towards this goal, which is based on a ``coarse-graining'' of the underlying distribution of fitnesses in the population.

  11. Sexual selection against deleterious mutations via variable male search success

    PubMed Central

    MacLellan, Kelsie; Whitlock, Michael C.; Rundle, Howard D.

    2009-01-01

    In many species, successful mating requires the initial step of actively searching for and locating a female. The overall health or condition of a male is likely to affect their ability to do this, making search effort a potentially important component of sexual fitness that may have important consequences for population mean fitness. We investigated the potential population genetic consequences of search effort using 10 populations of Drosophila melanogaster, each fixed for a different recessive mutation with a visible phenotypic effect. Mate choice trials were conducted in arenas of varying size, requiring different levels of search ability. Sexual selection against mutant males was stronger when increased search effort was included than when it was excluded. Varying abilities to find mates can substantially increase the strength of selection against deleterious alleles. PMID:19625301

  12. The deleterious role of basophils in systemic lupus erythematosus

    PubMed Central

    Pellefigues, Christophe; Charles, Nicolas

    2013-01-01

    Systemic lupus erythematosus is a complex autoimmune disease of multifactorial origins. All compartments of the immune system appear to be affected, at least in some way, and to contribute to disease pathogenesis. Due to an escape from negative selection autoreactive T and B cells accumulate in SLE patients leading to the production of autoantibodies mainly raised against nuclear components and their subsequent deposition into target organs. We recently showed that basophils, in an IgE and IL-4 dependent manner, contribute to SLE pathogenesis by amplifying autoantibody production. Here, we summarize what we have learned about the deleterious role of basophils in lupus both in a mouse model and in SLE patients. We discuss which possible pathways could be involved in basophil activation and recruitment to secondary lymphoid organs during SLE, and how basophils may amplify autoantibody production. PMID:24209595

  13. Mate choice among yeast gametes can purge deleterious mutations.

    PubMed

    Tazzyman, S J; Seymour, R M; Pomiankowski, A; Greig, D

    2012-08-01

    Meiosis in Saccharomyces yeast produces four haploid gametes that usually fuse with each other, an extreme form of self-fertilization among the products of a single meiosis known as automixis. The gametes signal to each other with sex pheromone. Better-quality gametes produce stronger signals and are preferred as mates. We suggest that the function of this signalling system is to enable mate choice among the four gametes from a single meiosis and so to promote the clearance of deleterious mutations. To support this claim, we construct a mathematical model that shows that signalling during automixis (i) improves the long-term fitness of a yeast colony and (ii) lowers its mutational load. We also show that the benefit to signalling is greater with larger numbers of segregating mutations.

  14. Betel nut chewing and its deleterious effects on oral cavity.

    PubMed

    Anand, Richa; Dhingra, Chandan; Prasad, Sumanth; Menon, Ipseeta

    2014-01-01

    The habit of chewing betel nut has a long history of use. Betel nut and products derived from it are widely used as a masticatory product among various communities and in several countries across the world. Over a long period, several additives have been added to a simple betel nut preparation; thus, creating the betel quid (BQ) and encompassing chewing tobacco in the preparation. Betel nut has deleterious effects on oral soft tissues. Its effects on dental caries and periodontal diseases, two major oral diseases are less well-documented. Betel-induced lichenoid lesions mainly on buccal mucosa have been reported at quid retained sites. In chronic chewers, a condition called betel chewers mucosa is often found where the quid is placed. Betel nut chewing is implicated in oral submucous fibrosis (OSF) and its use along with tobacco can cause leukoplakia, both of which are potentially malignant in the oral cavity. Oral cancer often arises from such precancerous changes. Thus, public health measures to quit betel use are recommended to control disabling conditions such as OSF and oral cancer.

  15. Endocrine dysfunction in sepsis: a beneficial or deleterious host response?

    PubMed

    Gheorghiţă, Valeriu; Barbu, Alina Elena; Gheorghiu, Monica Livia; Căruntu, Florin Alexandru

    2015-03-01

    Sepsis is a systemic, deleterious inflammatory host response triggered by an infective agent leading to severe sepsis, septic shock and multi-organ failure. The host response to infection involves a complex, organized and coherent interaction between immune, autonomic, neuroendocrine and behavioral systems. Recent data have confirmed that disturbances of the autonomic nervous and neuroendocrine systems could contribute to sepsis-induced organ dysfunction. Through this review, we aimed to summarize the current knowledge about the endocrine dysfunction as response to sepsis, specifically addressed to vasopressin, copeptin, cortisol, insulin and leptin. We searched the following readily accessible, clinically relevant databases: PubMed, UpToDate, BioMed Central. The immune system could be regarded as a "diffuse sensory organ" that signals the presence of pathogens to the brain through different pathways, such as the vagus nerve, endothelial activation/dysfunction, cytokines and neurotoxic mediators and the circumventricular organs, especially the neurohypophysis. The hormonal profile changes substantially as a consequence of inflammatory mediators and microorganism products leading to inappropriately low levels of vasopressin, sick euthyroid syndrome, reduced adrenal responsiveness to ACTH, insulin resistance, hyperglycemia as well as hyperleptinemia. In conclusion, clinical diagnosis of this "pan-endocrine illness" is frequently challenging due to the many limiting factors. The most important benefits of endocrine markers in the management of sepsis may be reflected by their potential to be used as biomarkers in different scoring systems to estimate the severity of the disease and the risk of death.

  16. An epidemiological study to know the prevalence of deleterious oral habits among 6 to 12 year old children

    PubMed Central

    Garde, J B; Suryavanshi, Rajendra K; Jawale, Bhushan Arun; Deshmukh, Vikramsingh; Dadhe, Dattaprasad P; Suryavanshi, Maneesha Kshirsagar

    2014-01-01

    Background: This study was taken to assess the prevalence of deleterious oral habits among 6-12 year old school going children. Materials & Methods: A sample size of 832 children was finalized with simple random sampling technique including 444 males and 388 females. To get the demographic information and presence of harmful oral habits a closed-ended questionnaire was developed. Clinical evaluation was also done using mirror and water tests. Chi-square test was done to compare the prevalence of oral habits among different age groups and gender at p<0.05. Results: Bruxism (17.3%) was most commonly seen followed by bottle feeding (10.1%), thumb sucking (8.7%), nail biting (5.8%), tongue thrusting (4.9%) and mouth breathing (4.3%). Prevalence of all deleterious habits were more among female children and it also showed significant differences according to age. Conclusion: The data showed high prevalence of these oral habits. This highlighted the need for preventive orthodontic treatment at early age of life so that future occurrence of malocclusion can be avoided. How to cite the article: Garde JB, Suryavanshi RK, Jawale BA, Deshmukh V, Dadhe DP, Suryavanshi MK. An epidemiological study to know the prevalence of deleterious oral habits among 6 to 12 year old children. J Int Oral Health 2014;6(1):39-43. PMID:24653601

  17. The role of the interactome in the maintenance of deleterious variability in human populations

    PubMed Central

    Garcia-Alonso, Luz; Jiménez-Almazán, Jorge; Carbonell-Caballero, Jose; Vela-Boza, Alicia; Santoyo-López, Javier; Antiñolo, Guillermo; Dopazo, Joaquin

    2014-01-01

    Recent genomic projects have revealed the existence of an unexpectedly large amount of deleterious variability in the human genome. Several hypotheses have been proposed to explain such an apparently high mutational load. However, the mechanisms by which deleterious mutations in some genes cause a pathological effect but are apparently innocuous in other genes remain largely unknown. This study searched for deleterious variants in the 1,000 genomes populations, as well as in a newly sequenced population of 252 healthy Spanish individuals. In addition, variants causative of monogenic diseases and somatic variants from 41 chronic lymphocytic leukaemia patients were analysed. The deleterious variants found were analysed in the context of the interactome to understand the role of network topology in the maintenance of the observed mutational load. Our results suggest that one of the mechanisms whereby the effect of these deleterious variants on the phenotype is suppressed could be related to the configuration of the protein interaction network. Most of the deleterious variants observed in healthy individuals are concentrated in peripheral regions of the interactome, in combinations that preserve their connectivity, and have a marginal effect on interactome integrity. On the contrary, likely pathogenic cancer somatic deleterious variants tend to occur in internal regions of the interactome, often with associated structural consequences. Finally, variants causative of monogenic diseases seem to occupy an intermediate position. Our observations suggest that the real pathological potential of a variant might be more a systems property rather than an intrinsic property of individual proteins. PMID:25261458

  18. Deleterious localized stress fields: the effects of boundaries and stiffness tailoring in anisotropic laminated plates

    PubMed Central

    Weaver, P. M.

    2016-01-01

    The safe design of primary load-bearing structures requires accurate prediction of stresses, especially in the vicinity of geometric discontinuities where deleterious three-dimensional stress fields can be induced. Even for thin-walled structures significant through-thickness stresses arise at edges and boundaries, and this is especially precarious for laminates of advanced fibre-reinforced composites because through-thickness stresses are the predominant drivers in delamination failure. Here, we use a higher-order equivalent single-layer model derived from the Hellinger–Reissner mixed variational principle to examine boundary layer effects in laminated plates comprising constant-stiffness and variable-stiffness laminae and deforming statically in cylindrical bending. The results show that zigzag deformations, which arise due to layerwise differences in the transverse shear moduli, drive boundary layers towards clamped edges and are therefore critically important in quantifying localized stress gradients. The relative significance of the boundary layer scales with the degree of layerwise anisotropy and the thickness to characteristic length ratio. Finally, we demonstrate that the phenomenon of alternating positive and negative transverse shearing deformation through the thickness of composite laminates, previously only observed at clamped boundaries, can also occur at other locations as a result of smoothly varying the material properties over the in-plane dimensions of the laminate. PMID:27843401

  19. Spatial heterogeneity in the strength of selection against deleterious alleles and the mutation load

    PubMed Central

    Roze, D

    2012-01-01

    According to current estimates of genomic deleterious mutation rates (which are often of the order 0.1–1) the mutation load (defined as a reduction in the average fitness of a population due to the presence of deleterious alleles) may be important in many populations. In this paper, I use multilocus simulations to explore the effect of spatial heterogeneity in the strength of selection against deleterious alleles on the mutation load (for example, it has been suggested that stressful environments may increase the strength of selection). These simulations show contrasted results: in some situations, spatial heterogeneity may greatly reduce the mutation load, due to the fact that migrants coming from demes under stronger selection carry relatively few deleterious alleles, and benefit from a strong advantage within demes under weaker selection (where individuals carry many more deleterious alleles); in other situations, however, deleterious alleles accumulate within demes under stronger selection, due to migration pressure from demes under weaker selection, leading to fitness erosion within those demes. This second situation is more frequent when the productivity of the different demes is proportional to their mean fitness. The effect of spatial heterogeneity is greatly reduced, however, when the response to environmental differences is inconsistent across loci. PMID:22588129

  20. Deleterious effects of reactive aldehydes and glycated proteins on macrophage proteasomal function: possible links between diabetes and atherosclerosis.

    PubMed

    Moheimani, Fatemeh; Morgan, Philip E; van Reyk, David M; Davies, Michael J

    2010-06-01

    People with diabetes experience chronic hyperglycemia and are at a high risk of developing atherosclerosis and microvascular disease. Reactions of glucose, or aldehydes derived from glucose (e.g. methylglyoxal, glyoxal, or glycolaldehyde), with proteins result in glycation that ultimately yield advanced glycation end products (AGE). AGE are present at elevated levels in plasma and atherosclerotic lesions from people with diabetes, and previous in vitro studies have postulated that the presence of these materials is deleterious to cell function. This accumulation of AGE and glycated proteins within cells may arise from either increased formation and/or ineffective removal by cellular proteolytic systems, such as the proteasomes, the major multi-enzyme complex that removes proteins within cells. In this study it is shown that whilst high glucose concentrations fail to modify proteasome enzyme activities in J774A.1 macrophage-like cell extracts, reactive aldehydes enhanced proteasomal enzyme activities. In contrast BSA, pre-treated with high glucose for 8 weeks, inhibited both the chymotrypsin-like and caspase-like activities. BSA glycated using methylglyoxal or glycolaldehyde, also inhibited proteasomal activity though to differing extents. This suppression of proteasome activity by glycated proteins may result in further intracellular accumulation of glycated proteins with subsequent deleterious effects on cellular function.

  1. Relative Effectiveness of Mating Success and Sperm Competition at Eliminating Deleterious Mutations in Drosophila melanogaster

    PubMed Central

    Clark, Sean C. A.; Sharp, Nathaniel P.; Rowe, Locke; Agrawal, Aneil F.

    2012-01-01

    Condition-dependence theory predicts that sexual selection will facilitate adaptation by selecting against deleterious mutations that affect the expression of sexually selected traits indirectly via condition. Recent empirical studies have provided support for this prediction; however, their results do not elucidate the relative effects of pre- and postcopulatory sexual selection on deleterious mutations. We used the Drosophila melanogaster model system to discern the relative contributions of pre- and postcopulatory processes to selection against deleterious mutations. To assess second-male ejaculate competition success (P2; measured as the proportion of offspring attributable to the experimental male) and mating success, mutant and wild-type male D. melanogaster were given the opportunity to mate with females that were previously mated to a standard competitor male. This process was repeated for males subjected to a diet quality manipulation to test for effects of environmentally-manipulated condition on P2 and mating success. While none of the tested mutations affected P2, there was a clear effect of condition. Conversely, several of the mutations affected mating success, while condition showed no effect. Our results suggest that precopulatory selection may be more effective than postcopulatory selection at removing deleterious mutations. The opposite result obtained for our diet manipulation points to an interesting discrepancy between environmental and genetic manipulations of condition, which may be explained by the multidimensionality of condition. Establishing whether the various stages of sexual selection affect deleterious mutations differently, and to what extent, remains an important issue to resolve. PMID:22662148

  2. A Temporal Perspective on the Interplay of Demography and Selection on Deleterious Variation in Humans

    PubMed Central

    Koch, Evan; Novembre, John

    2017-01-01

    When mutations have small effects on fitness, population size plays an important role in determining the amount and nature of deleterious genetic variation. The extent to which recent population size changes have impacted deleterious variation in humans has been a question of considerable interest and debate. An emerging consensus is that the Out-of-Africa bottleneck and subsequent growth events have been too short to cause meaningful differences in genetic load between populations; though changes in the number and average frequencies of deleterious variants have taken place. To provide more support for this view and to offer additional insight into the divergent evolution of deleterious variation across populations, we numerically solve time-inhomogeneous diffusion equations and study the temporal dynamics of the frequency spectra in models of population size change for modern humans. We observe how the response to demographic change differs by the strength of selection, and we then assess whether similar patterns are observed in exome sequence data from 33,370 and 5203 individuals of non-Finnish European and West African ancestry, respectively. Our theoretical results highlight how even simple summaries of the frequency spectrum can have complex responses to demographic change. These results support the finding that some apparent discrepancies between previous results have been driven by the behaviors of the precise summaries of deleterious variation. Further, our empirical results make clear the difficulty of inferring slight differences in frequency spectra using recent next-generation sequence data. PMID:28159863

  3. Excess of Deleterious Mutations around HLA Genes Reveals Evolutionary Cost of Balancing Selection

    PubMed Central

    Lenz, Tobias L.; Spirin, Victor; Jordan, Daniel M.; Sunyaev, Shamil R.

    2016-01-01

    Deleterious mutations are expected to evolve under negative selection and are usually purged from the population. However, deleterious alleles segregate in the human population and some disease-associated variants are maintained at considerable frequencies. Here, we test the hypothesis that balancing selection may counteract purifying selection in neighboring regions and thus maintain deleterious variants at higher frequency than expected from their detrimental fitness effect. We first show in realistic simulations that balancing selection reduces the density of polymorphic sites surrounding a locus under balancing selection, but at the same time markedly increases the population frequency of the remaining variants, including even substantially deleterious alleles. To test the predictions of our simulations empirically, we then use whole-exome sequencing data from 6,500 human individuals and focus on the most established example for balancing selection in the human genome, the major histocompatibility complex (MHC). Our analysis shows an elevated frequency of putatively deleterious coding variants in nonhuman leukocyte antigen (non-HLA) genes localized in the MHC region. The mean frequency of these variants declined with physical distance from the classical HLA genes, indicating dependency on genetic linkage. These results reveal an indirect cost of the genetic diversity maintained by balancing selection, which has hitherto been perceived as mostly advantageous, and have implications both for the evolution of recombination and also for the epidemiology of various MHC-associated diseases. PMID:27436009

  4. Estimate of the genomic mutation rate deleterious to overall fitness in E. coll

    NASA Astrophysics Data System (ADS)

    Kibota, Travis T.; Lynch, Michael

    1996-06-01

    MUTATIONS are a double-edged sword: they are the ultimate source of genetic variation upon which evolution depends, yet most mutations affecting fitness (viability and reproductive success) appear to be harmful1. Deleterious mutations of small effect can escape natural selection, and should accumulate in small populations2-4. Reduced fitness from deleterious-mutation accumulation may be important in the evolution of sex5-7, mate choice8,9, and diploid life-cycles10, and in the extinction of small populations11,12. Few empirical data exist, however. Minimum estimates of the genomic deleterious-mutation rate for viability in Drosophila melanogaster are surprisingly high1,13,14, leading to the conjecture that the rate for total fitness could exceed 1.0 mutation per individual per generation5,6. Here we use Escherichia coli to provide an estimate of the genomic deleterious-mutation rate for total fitness in a microbe. We estimate that the per-microbe rate of deleterious mutations is in excess of 0.0002.

  5. Parasites and deleterious mutations: interactions influencing the evolutionary maintenance of sex.

    PubMed

    Park, A W; Jokela, J; Michalakis, Y

    2010-05-01

    The restrictive assumptions associated with purely genetic and purely ecological mechanisms suggest that neither of the two forces, in isolation, can offer a general explanation for the evolutionary maintenance of sex. Consequently, attention has turned to pluralistic models (i.e. models that apply both ecological and genetic mechanisms). Existing research has shown that combining mutation accumulation and parasitism allows restrictive assumptions about genetic and parasite parameter values to be relaxed while still predicting the maintenance of sex. However, several empirical studies have shown that deleterious mutations and parasitism can reduce fitness to a greater extent than would be expected if the two acted independently. We show how interactions between these genetic and ecological forces can completely reverse predictions about the evolution of reproductive modes. Moreover, we demonstrate that synergistic interactions between infection and deleterious mutations can render sex evolutionarily stable even when there is antagonistic epistasis among deleterious mutations, thereby widening the conditions for the evolutionary maintenance of sex.

  6. Two classes of deleterious recessive alleles in a natural population of zebrafish, Danio rerio.

    PubMed Central

    McCune, Amy R.; Houle, David; McMillan, Kyle; Annable, Rebecca; Kondrashov, Alexey S.

    2004-01-01

    Natural populations carry deleterious recessive alleles which cause inbreeding depression. We compared mortality and growth of inbred and outbred zebrafish, Danio rerio, between 6 and 48 days of age. Grandparents of the studied fish were caught in the wild. Inbred fish were generated by brother-sister mating. Mortality was 9% in outbred fish, and 42% in inbred fish, which implies at least 3.6 lethal equivalents of deleterious recessive alleles per zygote. There was no significant inbreeding depression in the growth, perhaps because the surviving inbred fish lived under less crowded conditions. In contrast to alleles that cause embryonic and early larval mortality in the same population, alleles responsible for late larval and early juvenile mortality did not result in any gross morphological abnormalities. Thus, deleterious recessive alleles that segregate in a wild zebrafish population belong to two sharply distinct classes: early-acting, morphologically overt, unconditional lethals; and later-acting, morphologically cryptic, and presumably milder alleles. PMID:15451692

  7. Bottlenecks and selective sweeps during domestication have increased deleterious genetic variation in dogs

    PubMed Central

    Marsden, Clare D.; Ortega-Del Vecchyo, Diego; O’Brien, Dennis P.; Taylor, Jeremy F.; Ramirez, Oscar; Vilà, Carles; Marques-Bonet, Tomas; Schnabel, Robert D.; Wayne, Robert K.; Lohmueller, Kirk E.

    2016-01-01

    Population bottlenecks, inbreeding, and artificial selection can all, in principle, influence levels of deleterious genetic variation. However, the relative importance of each of these effects on genome-wide patterns of deleterious variation remains controversial. Domestic and wild canids offer a powerful system to address the role of these factors in influencing deleterious variation because their history is dominated by known bottlenecks and intense artificial selection. Here, we assess genome-wide patterns of deleterious variation in 90 whole-genome sequences from breed dogs, village dogs, and gray wolves. We find that the ratio of amino acid changing heterozygosity to silent heterozygosity is higher in dogs than in wolves and, on average, dogs have 2–3% higher genetic load than gray wolves. Multiple lines of evidence indicate this pattern is driven by less efficient natural selection due to bottlenecks associated with domestication and breed formation, rather than recent inbreeding. Further, we find regions of the genome implicated in selective sweeps are enriched for amino acid changing variants and Mendelian disease genes. To our knowledge, these results provide the first quantitative estimates of the increased burden of deleterious variants directly associated with domestication and have important implications for selective breeding programs and the conservation of rare and endangered species. Specifically, they highlight the costs associated with selective breeding and question the practice favoring the breeding of individuals that best fit breed standards. Our results also suggest that maintaining a large population size, rather than just avoiding inbreeding, is a critical factor for preventing the accumulation of deleterious variants. PMID:26699508

  8. Bottlenecks and selective sweeps during domestication have increased deleterious genetic variation in dogs.

    PubMed

    Marsden, Clare D; Ortega-Del Vecchyo, Diego; O'Brien, Dennis P; Taylor, Jeremy F; Ramirez, Oscar; Vilà, Carles; Marques-Bonet, Tomas; Schnabel, Robert D; Wayne, Robert K; Lohmueller, Kirk E

    2016-01-05

    Population bottlenecks, inbreeding, and artificial selection can all, in principle, influence levels of deleterious genetic variation. However, the relative importance of each of these effects on genome-wide patterns of deleterious variation remains controversial. Domestic and wild canids offer a powerful system to address the role of these factors in influencing deleterious variation because their history is dominated by known bottlenecks and intense artificial selection. Here, we assess genome-wide patterns of deleterious variation in 90 whole-genome sequences from breed dogs, village dogs, and gray wolves. We find that the ratio of amino acid changing heterozygosity to silent heterozygosity is higher in dogs than in wolves and, on average, dogs have 2-3% higher genetic load than gray wolves. Multiple lines of evidence indicate this pattern is driven by less efficient natural selection due to bottlenecks associated with domestication and breed formation, rather than recent inbreeding. Further, we find regions of the genome implicated in selective sweeps are enriched for amino acid changing variants and Mendelian disease genes. To our knowledge, these results provide the first quantitative estimates of the increased burden of deleterious variants directly associated with domestication and have important implications for selective breeding programs and the conservation of rare and endangered species. Specifically, they highlight the costs associated with selective breeding and question the practice favoring the breeding of individuals that best fit breed standards. Our results also suggest that maintaining a large population size, rather than just avoiding inbreeding, is a critical factor for preventing the accumulation of deleterious variants.

  9. [Study on species and valence state of heavy metals and deleterious elements of mineral medicine].

    PubMed

    Han, Xu; Luo, Jiao-yang; Liu, Qiu-tao; Li, Yan-jun; Xie, Yan-jun; Yang, Shi-hai; Yang, Mei-hua

    2015-12-01

    As an important part of traditional Chinese medicine (TCM), mineral medicine plays an irreplaceable role. However, little has been reported on its species and valence state of heavy metals and deleterious elements, and also the relevance to pharmacological effect and toxicology. The present paper, in a new perspective, summarized the determination of the species and valence state of heavy metals and deleterious elements in recent years, discussed the progress of the pharmacological effect and toxicology, and prospected for future study which might provide reference for mineral medicine.

  10. Separating multiple, short-term deleterious effects of saline solutions to the growth of cowpea seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reductions in plant growth due to salinity are of global importance in natural and agricultural landscapes. Short-term (48 h) solution culture experiments studied 404 treatments with seedlings of cowpea (Vigna unguiculata (L.) Walp. cv. Caloona) to examine the multiple deleterious effects of Ca, Mg...

  11. On the retention of gene duplicates prone to dominant deleterious mutations.

    PubMed

    Malaguti, Giulia; Singh, Param Priya; Isambert, Hervé

    2014-05-01

    Recent studies have shown that gene families from different functional categories have been preferentially expanded either by small scale duplication (SSD) or by whole-genome duplication (WGD). In particular, gene families prone to dominant deleterious mutations and implicated in cancers and other genetic diseases in human have been greatly expanded through two rounds of WGD dating back from early vertebrates. Here, we strengthen this intriguing observation, showing that human oncogenes involved in different primary tumors have retained many WGD duplicates compared to other human genes. In order to rationalize this evolutionary outcome, we propose a consistent population genetics model to analyze the retention of SSD and WGD duplicates taking into account their propensity to acquire dominant deleterious mutations. We solve a deterministic haploid model including initial duplicated loci, their retention through sub-functionalization or their neutral loss-of-function or deleterious gain-of-function at one locus. Extensions to diploid genotypes are presented and population size effects are analyzed using stochastic simulations. The only difference between the SSD and WGD scenarios is the initial number of individuals with duplicated loci. While SSD duplicates need to spread through the entire population from a single individual to reach fixation, WGD duplicates are de facto fixed in the small initial post-WGD population arising through the ploidy incompatibility between post-WGD individuals and the rest of the pre-WGD population. WGD duplicates prone to dominant deleterious mutations are then shown to be indirectly selected through purifying selection in post-WGD species, whereas SSD duplicates typically require positive selection. These results highlight the long-term evolution mechanisms behind the surprising accumulation of WGD duplicates prone to dominant deleterious mutations and are shown to be consistent with cancer genome data on the prevalence of human

  12. The accumulation of deleterious mutations in rice genomes: a hypothesis on the cost of domestication.

    PubMed

    Lu, Jian; Tang, Tian; Tang, Hua; Huang, Jianzi; Shi, Suhua; Wu, Chung-I

    2006-03-01

    The extent of molecular differentiation between domesticated animals or plants and their wild relatives is postulated to be small. The availability of the complete genome sequences of two subspecies of the Asian rice, Oryza sativa (indica and japonica) and their wild relatives have provided an unprecedented opportunity to study divergence following domestication. We observed significantly more amino acid substitutions during rice domestication than can be expected from a comparison among wild species. This excess is disproportionately larger for the more radical kinds of amino acid changes (e.g. Cys<-->Tyr). We estimate that approximately a quarter of the amino acid differences between rice cultivars are deleterious, not accountable by the relaxation of selective constraints. This excess is negatively correlated with the rate of recombination, suggesting that 'hitchhiking' has occurred. We hypothesize that during domestication artificial selection increased the frequency of many deleterious mutations.

  13. Dynamics and Fate of Beneficial Mutations Under Lineage Contamination by Linked Deleterious Mutations.

    PubMed

    Pénisson, Sophie; Singh, Tanya; Sniegowski, Paul; Gerrish, Philip

    2017-03-01

    Beneficial mutations drive adaptive evolution, yet their selective advantage does not ensure their fixation. Haldane's application of single-type branching process theory showed that genetic drift alone could cause the extinction of newly arising beneficial mutations with high probability. With linkage, deleterious mutations will affect the dynamics of beneficial mutations and might further increase their extinction probability. Here, we model the lineage dynamics of a newly arising beneficial mutation as a multitype branching process. Our approach accounts for the combined effects of drift and the stochastic accumulation of linked deleterious mutations, which we call lineage contamination We first study the lineage-contamination phenomenon in isolation, deriving dynamics and survival probabilities (the complement of extinction probabilities) of beneficial lineages. We find that survival probability is zero when [Formula: see text] where U is deleterious mutation rate and [Formula: see text] is the selective advantage of the beneficial mutation in question, and is otherwise depressed below classical predictions by a factor bounded from below by [Formula: see text] We then put the lineage contamination phenomenon into the context of an evolving population by incorporating the effects of background selection. We find that, under the combined effects of lineage contamination and background selection, ensemble survival probability is never zero but is depressed below classical predictions by a factor bounded from below by [Formula: see text] where [Formula: see text] is mean selective advantage of beneficial mutations, and [Formula: see text] This factor, and other bounds derived from it, are independent of the fitness effects of deleterious mutations. At high enough mutation rates, lineage contamination can depress fixation probabilities to values that approach zero. This fact suggests that high mutation rates can, perhaps paradoxically, (1) alleviate competition

  14. Targeted next-generation sequencing reveals multiple deleterious variants in OPLL-associated genes

    PubMed Central

    Chen, Xin; Guo, Jun; Cai, Tao; Zhang, Fengshan; Pan, Shengfa; Zhang, Li; Wang, Shaobo; Zhou, Feifei; Diao, Yinze; Zhao, Yanbin; Chen, Zhen; Liu, Xiaoguang; Chen, Zhongqiang; Liu, Zhongjun; Sun, Yu; Du, Jie

    2016-01-01

    Ossification of the posterior longitudinal ligament of the spine (OPLL), which is characterized by ectopic bone formation in the spinal ligaments, can cause spinal-cord compression. To date, at least 11 susceptibility genes have been genetically linked to OPLL. In order to identify potential deleterious alleles in these OPLL-associated genes, we designed a capture array encompassing all coding regions of the target genes for next-generation sequencing (NGS) in a cohort of 55 unrelated patients with OPLL. By bioinformatics analyses, we successfully identified three novel and five extremely rare variants (MAF < 0.005). These variants were predicted to be deleterious by commonly used various algorithms, thereby resulting in missense mutations in four OPLL-associated genes (i.e., COL6A1, COL11A2, FGFR1, and BMP2). Furthermore, potential effects of the patient with p.Q89E of BMP2 were confirmed by a markedly increased BMP2 level in peripheral blood samples. Notably, seven of the variants were found to be associated with the patients with continuous subtype changes by cervical spinal radiological analyses. Taken together, our findings revealed for the first time that deleterious coding variants of the four OPLL-associated genes are potentially pathogenic in the patients with OPLL. PMID:27246988

  15. Sexual selection is ineffectual or inhibits the purging of deleterious mutations in Drosophila melanogaster.

    PubMed

    Arbuthnott, Devin; Rundle, Howard D

    2012-07-01

    The effects of sexual selection on population mean fitness are unclear and a subject of debate. Recent models propose that, because reproductive success may be condition dependent, much of the genome may be a target of sexual selection. Under this scenario, mutations that reduce health, and thus nonsexual fitness, may also be deleterious with respect to reproductive success, meaning that sexual selection may contribute to the purging of deleterious alleles. We tested this hypothesis directly by subjecting replicate Drosophila melanogaster populations to two treatments that altered the opportunity for sexual selection and then tracked changes in the frequency of six separate deleterious alleles with recessive and visible phenotypic effects. While natural selection acted to decrease the frequency of all six mutations, the addition of sexual selection did not aid in the purging of any of them, and for three of them appears to have hampered it. Courtship and mating have harmful effects in this species and mate choice assays showed that males directed more courtship and mating behavior toward wild-type over mutant females, providing a likely explanation for sexual selection's cost. Whether this cost extends to other mutations (e.g., those lacking visible phenotypic effects) is an important topic for future research.

  16. Somatic deleterious mutation rate in a woody plant: estimation from phenotypic data

    PubMed Central

    Bobiwash, K; Schultz, S T; Schoen, D J

    2013-01-01

    We conducted controlled crosses in populations of the long-lived clonal shrub, Vaccinium angustifolium (lowbush blueberry) to estimate inbreeding depression and mutation parameters associated with somatic deleterious mutation. Inbreeding depression level was high, with many plants failing to set fruit after self-pollination. We also compared fruit set from autogamous pollinations (pollen collected from within the same inflorescence) with fruit set from geitonogamous pollinations (pollen collected from the same plant but from inflorescences separated by several meters of branch growth). The difference between geitonogamous versus autogamous fitness within single plants is referred to as ‘autogamy depression' (AD). AD can be caused by somatic deleterious mutation. AD was significantly different from zero for fruit set. We developed a maximum-likelihood procedure to estimate somatic mutation parameters from AD, and applied it to geitonogamous and autogamous fruit set data from this experiment. We infer that, on average, approximately three sublethal, partially dominant somatic mutations exist within the crowns of the plants studied. We conclude that somatic mutation in this woody plant results in an overall genomic deleterious mutation rate that exceeds the rate measured to date for annual plants. Some implications of this result for evolutionary biology and agriculture are discussed. PMID:23778990

  17. Pathway to neural resilience: Self-esteem buffers against deleterious effects of poverty on the hippocampus.

    PubMed

    Wang, Yinan; Zhang, Lin; Kong, Xiangzhen; Hong, Yingyi; Cheon, Bobby; Liu, Jia

    2016-11-01

    Human neuroimaging studies have shown that people living in poverty tend to suffer hippocampal atrophy, which leads to impaired memory and learning throughout life. However, behavioral studies demonstrate that poor people with high self-esteem are often exempt from the deleterious effect of poverty and instead possess a happy and successful life. Here we investigated whether high self-esteem can buffer against the deleterious effects of poverty, as indicated by low subjective socioeconomic status (SSS), on the hippocampal gray matter volume (GMV) in a large cohort of young participants (N = 280). As expected, findings revealed that although low (vs. high) SSS was linked with a smaller hippocampal GMV, the deleterious effect of low SSS on hippocampal GMV was alleviated when the participants have high self-esteem. Commonality analyses further confirmed this observation. The current study suggests that positive psychological resources such as self-esteem may provide protection for the hippocampal atrophy in adversity. Hum Brain Mapp 37:3757-3766, 2016. © 2016 Wiley Periodicals, Inc.

  18. [Reduction of a risk of the deleterious effects of persistent toxic substances on the health of the far north population].

    PubMed

    Dudarev, A A; Mizerniuk, V N; Chupakhin, V S; Lebedev, G B; Chashchin, V P

    2010-01-01

    The paper presents the general principles and procedure of the development and implementation of measures to decrease and prevent environmental pollution with persistent toxic substances (PTS) in the Russian Arctic and, accordingly, to reduce a risk of the deleterious effects of PTS on human health. Based on the results of a study of PTS in the Russian Arctic (from the Kola Peninsula to Chukotka), the authors first systematized the basic lines and actions and formulated specific measures to reduce the North population's exposure to PTSs, such as polychlorinated biphenyls, organic chlorine pesticides (dichlorodiphenyltrichloroethane, hexachlorocyclohexane, hexachlorobenzene, etc.), and heavy metals (mercury, lead, cadmium). A package of measures is aimed at maximally reducing the presence of PTS-containing objects and materials in the north (via detection, collection, and extermination), at neutralizing the soils in settlement lands, at setting up safe water consumption systems, at organizing effective control over the safe use of chemicals and the levels of PTS in raw food materials and foodstuffs, and at working out recommendations on safe procedures for food purchase, storage, and cooking.

  19. SDS, a structural disruption score for assessment of missense variant deleteriousness

    PubMed Central

    Preeprem, Thanawadee; Gibson, Greg

    2014-01-01

    We have developed a novel structure-based evaluation for missense variants that explicitly models protein structure and amino acid properties to predict the likelihood that a variant disrupts protein function. A structural disruption score (SDS) is introduced as a measure to depict the likelihood that a case variant is functional. The score is constructed using characteristics that distinguish between causal and neutral variants within a group of proteins. The SDS score is correlated with standard sequence-based deleteriousness, but shows promise for improving discrimination between neutral and causal variants at less conserved sites. The prediction was performed on 3-dimentional structures of 57 gene products whose homozygous SNPs were identified as case-exclusive variants in an exome sequencing study of epilepsy disorders. We contrasted the candidate epilepsy variants with scores for likely benign variants found in the EVS database, and for positive control variants in the same genes that are suspected to promote a range of diseases. To derive a characteristic profile of damaging SNPs, we transformed continuous scores into categorical variables based on the score distribution of each measurement, collected from all possible SNPs in this protein set, where extreme measures were assumed to be deleterious. A second epilepsy dataset was used to replicate the findings. Causal variants tend to receive higher sequence-based deleterious scores, induce larger physico-chemical changes between amino acid pairs, locate in protein domains, buried sites or on conserved protein surface clusters, and cause protein destabilization, relative to negative controls. These measures were agglomerated for each variant. A list of nine high-priority putative functional variants for epilepsy was generated. Our newly developed SDS protocol facilitates SNP prioritization for experimental validation. PMID:24795746

  20. High-protein-low-carbohydrate diet: deleterious metabolic and cardiovascular effects depend on age.

    PubMed

    Bedarida, Tatiana; Baron, Stephanie; Vessieres, Emilie; Vibert, Francoise; Ayer, Audrey; Marchiol-Fournigault, Carmen; Henrion, Daniel; Paul, Jean-Louis; Noble, Florence; Golmard, Jean-Louis; Beaudeux, Jean-Louis; Cottart, Charles-Henry; Nivet-Antoine, Valerie

    2014-09-01

    High-protein-low-carbohydrate (HP-LC) diets have become widespread. Yet their deleterious consequences, especially on glucose metabolism and arteries, have already been underlined. Our previous study (2) has already shown glucose intolerance with major arterial dysfunction in very old mice subjected to an HP-LC diet. The hypothesis of this work was that this diet had an age-dependent deleterious metabolic and cardiovascular outcome. Two groups of mice, young and adult (3 and 6 mo old), were subjected for 12 wk to a standard or to an HP-LC diet. Glucose and lipid metabolism was studied. The cardiovascular system was explored from the functional stage with Doppler-echography to the molecular stage (arterial reactivity, mRNA, immunohistochemistry). Young mice did not exhibit any significant metabolic modification, whereas adult mice presented marked glucose intolerance associated with an increase in resistin and triglyceride levels. These metabolic disturbances were responsible for cardiovascular damages only in adult mice, with decreased aortic distensibility and left ventricle dysfunction. These seemed to be the consequence of arterial dysfunctions. Mesenteric arteries were the worst affected with a major oxidative stress, whereas aorta function seemed to be maintained with an appreciable role of cyclooxygenase-2 to preserve endothelial function. This study highlights for the first time the age-dependent deleterious effects of an HP-LC diet on metabolism, with glucose intolerance and lipid disorders and vascular (especially microvessels) and cardiac functions. This work shows that HP-LC lead to equivalent cardiovascular alterations, as observed in very old age, and underlines the danger of such diet.

  1. Analysis of the Estimators of the Average Coefficient of Dominance of Deleterious Mutations

    PubMed Central

    Fernández, B.; García-Dorado, A.; Caballero, A.

    2004-01-01

    We investigate the sources of bias that affect the most commonly used methods of estimation of the average degree of dominance (h) of deleterious mutations, focusing on estimates from segregating populations. The main emphasis is on the effect of the finite size of the populations, but other sources of bias are also considered. Using diffusion approximations to the distribution of gene frequencies in finite populations as well as stochastic simulations, we assess the behavior of the estimators obtained from populations at mutation-selection-drift balance under different mutational scenarios and compare averages of h for newly arisen and segregating mutations. Because of genetic drift, the inferences concerning newly arisen mutations based on the mutation-selection balance theory can have substantial upward bias depending upon the distribution of h. In addition, estimates usually refer to h weighted by the homozygous deleterious effect in different ways, so that inferences are complicated when these two variables are negatively correlated. Due to both sources of bias, the widely used regression of heterozygous on homozygous means underestimates the arithmetic mean of h for segregating mutations, in contrast to their repeatedly assumed equality in the literature. We conclude that none of the estimators from segregating populations provides, under general conditions, a useful tool to ascertain the properties of the degree of dominance, either for segregating or for newly arisen deleterious mutations. Direct estimates of the average h from mutation-accumulation experiments are shown to suffer some bias caused by purging selection but, because they do not require assumptions on the causes maintaining segregating variation, they appear to give a more reliable average dominance for newly arisen mutations. PMID:15514075

  2. Quorum-sensing inhibition abrogates the deleterious impact of Pseudomonas aeruginosa on airway epithelial repair.

    PubMed

    Ruffin, Manon; Bilodeau, Claudia; Maillé, Émilie; LaFayette, Shantelle L; McKay, Geoffrey A; Trinh, Nguyen Thu Ngan; Beaudoin, Trevor; Desrosiers, Martin-Yvon; Rousseau, Simon; Nguyen, Dao; Brochiero, Emmanuelle

    2016-09-01

    Chronic Pseudomonas aeruginosa lung infections are associated with progressive epithelial damage and lung function decline. In addition to its role in tissue injury, the persistent presence of P. aeruginosa-secreted products may also affect epithelial repair ability, raising the need for new antivirulence therapies. The purpose of our study was to better understand the outcomes of P. aeruginosa exoproducts exposure on airway epithelial repair processes to identify a strategy to counteract their deleterious effect. We found that P. aeruginosa exoproducts significantly decreased wound healing, migration, and proliferation rates, and impaired the ability of directional migration of primary non-cystic fibrosis (CF) human airway epithelial cells. Impact of exoproducts was inhibited after mutations in P. aeruginosa genes that encoded for the quorum-sensing (QS) transcriptional regulator, LasR, and the elastase, LasB, whereas impact was restored by LasB induction in ΔlasR mutants. P. aeruginosa purified elastase also induced a significant decrease in non-CF epithelial repair, whereas protease inhibition with phosphoramidon prevented the effect of P. aeruginosa exoproducts. Furthermore, treatment of P. aeruginosa cultures with 4-hydroxy-2,5-dimethyl-3(2H)-furanone, a QS inhibitor, abrogated the negative impact of P. aeruginosa exoproducts on airway epithelial repair. Finally, we confirmed our findings in human airway epithelial cells from patients with CF, a disease featuring P. aeruginosa chronic respiratory infection. These data demonstrate that secreted proteases under the control of the LasR QS system impair airway epithelial repair and that QS inhibitors could be of benefit to counteract the deleterious effect of P. aeruginosa in infected patients.-Ruffin, M., Bilodeau, C., Maillé, É., LaFayette, S. L., McKay, G. A., Trinh, N. T. N., Beaudoin, T., Desrosiers, M.-Y., Rousseau, S., Nguyen, D., Brochiero, E. Quorum-sensing inhibition abrogates the deleterious impact

  3. Analysis of the estimators of the average coefficient of dominance of deleterious mutations.

    PubMed

    Fernández, B; García-Dorado, A; Caballero, A

    2004-10-01

    We investigate the sources of bias that affect the most commonly used methods of estimation of the average degree of dominance (h) of deleterious mutations, focusing on estimates from segregating populations. The main emphasis is on the effect of the finite size of the populations, but other sources of bias are also considered. Using diffusion approximations to the distribution of gene frequencies in finite populations as well as stochastic simulations, we assess the behavior of the estimators obtained from populations at mutation-selection-drift balance under different mutational scenarios and compare averages of h for newly arisen and segregating mutations. Because of genetic drift, the inferences concerning newly arisen mutations based on the mutation-selection balance theory can have substantial upward bias depending upon the distribution of h. In addition, estimates usually refer to h weighted by the homozygous deleterious effect in different ways, so that inferences are complicated when these two variables are negatively correlated. Due to both sources of bias, the widely used regression of heterozygous on homozygous means underestimates the arithmetic mean of h for segregating mutations, in contrast to their repeatedly assumed equality in the literature. We conclude that none of the estimators from segregating populations provides, under general conditions, a useful tool to ascertain the properties of the degree of dominance, either for segregating or for newly arisen deleterious mutations. Direct estimates of the average h from mutation-accumulation experiments are shown to suffer some bias caused by purging selection but, because they do not require assumptions on the causes maintaining segregating variation, they appear to give a more reliable average dominance for newly arisen mutations.

  4. Increased burden of de novo predicted deleterious variants in complex congenital diaphragmatic hernia

    PubMed Central

    Yu, Lan; Sawle, Ashley D.; Wynn, Julia; Aspelund, Gudrun; Stolar, Charles J.; Arkovitz, Marc S.; Potoka, Douglas; Azarow, Kenneth S.; Mychaliska, George B.; Shen, Yufeng; Chung, Wendy K.

    2015-01-01

    Congenital diaphragmatic hernia (CDH) is a serious birth defect that accounts for 8% of all major birth anomalies. Approximately 40% of cases occur in association with other anomalies. As sporadic complex CDH likely has a significant impact on reproductive fitness, we hypothesized that de novo variants would account for the etiology in a significant fraction of cases. We performed exome sequencing in 39 CDH trios and compared the frequency of de novo variants with 787 unaffected controls from the Simons Simplex Collection. We found no significant difference in overall frequency of de novo variants between cases and controls. However, among genes that are highly expressed during diaphragm development, there was a significant burden of likely gene disrupting (LGD) and predicted deleterious missense variants in cases (fold enrichment = 3.2, P-value = 0.003), and these genes are more likely to be haploinsufficient (P-value = 0.01) than the ones with benign missense or synonymous de novo variants in cases. After accounting for the frequency of de novo variants in the control population, we estimate that 15% of sporadic complex CDH patients are attributable to de novo LGD or deleterious missense variants. We identified several genes with predicted deleterious de novo variants that fall into common categories of genes related to transcription factors and cell migration that we believe are related to the pathogenesis of CDH. These data provide supportive evidence for novel genes in the pathogenesis of CDH associated with other anomalies and suggest that de novo variants play a significant role in complex CDH cases. PMID:26034137

  5. Increased burden of deleterious variants in essential genes in autism spectrum disorder

    PubMed Central

    Kember, Rachel L.; Brown, Christopher D.; Bućan, Maja

    2016-01-01

    Autism spectrum disorder (ASD) is a heterogeneous, highly heritable neurodevelopmental syndrome characterized by impaired social interaction, communication, and repetitive behavior. It is estimated that hundreds of genes contribute to ASD. We asked if genes with a strong effect on survival and fitness contribute to ASD risk. Human orthologs of genes with an essential role in pre- and postnatal development in the mouse [essential genes (EGs)] are enriched for disease genes and under strong purifying selection relative to human orthologs of mouse genes with a known nonlethal phenotype [nonessential genes (NEGs)]. This intolerance to deleterious mutations, commonly observed haploinsufficiency, and the importance of EGs in development suggest a possible cumulative effect of deleterious variants in EGs on complex neurodevelopmental disorders. With a comprehensive catalog of 3,915 mammalian EGs, we provide compelling evidence for a stronger contribution of EGs to ASD risk compared with NEGs. By examining the exonic de novo and inherited variants from 1,781 ASD quartet families, we show a significantly higher burden of damaging mutations in EGs in ASD probands compared with their non-ASD siblings. The analysis of EGs in the developing brain identified clusters of coexpressed EGs implicated in ASD. Finally, we suggest a high-priority list of 29 EGs with potential ASD risk as targets for future functional and behavioral studies. Overall, we show that large-scale studies of gene function in model organisms provide a powerful approach for prioritization of genes and pathogenic variants identified by sequencing studies of human disease. PMID:27956632

  6. Asperger syndrome and early-onset schizophrenia associated with a novel MECP2 deleterious missense variant.

    PubMed

    Curie, Aurore; Lesca, Gaëtan; Bussy, Gérald; Manificat, Sabine; Arnaud, Valérie; Gonzalez, Sibylle; Revol, Olivier; Calender, Alain; Gérard, Daniel; des Portes, Vincent

    2017-02-27

    Methyl-CpG-binding protein 2 (MECP2) deleterious variants, which are responsible for Rett syndrome in girls, are involved in a wide spectrum of developmental disabilities in males. A neuropsychiatric phenotype without intellectual disability is uncommon in patients with MECP2 deleterious variants. We report on two dizygotic twins with an MECP2-related psychiatric disorder without intellectual disability. Neuropsychological and psychiatric phenotype assessments were performed, and a genetic analysis was carried out. Both patients fulfilled the Pervasive Developmental Disorder criteria on Autism Diagnostic Observation Schedule and Asperger syndrome criteria on Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV). One patient developed early-onset schizophrenia (DSM-IV criteria) with two acute psychotic episodes, the latest one following corticosteroids and sodium valproate intake, with major hyperammonemia. A novel MECP2 gene transversion c.491 G>T [p.(Ser164Ile)] was found in both twins. Pathogenicity of this variant was considered on the basis of strong clinical and molecular data. The underlying molecular basis of neuropsychiatric disorders may have important consequences on genetic counseling and therapeutic strategies.

  7. Deleterious mutation in GPR88 is associated with chorea, speech delay, and learning disabilities

    PubMed Central

    Alkufri, Fadi; Shaag, Avraham; Abu-Libdeh, Bassam

    2016-01-01

    Objective: To identify the underlying molecular basis of a familial developmental disorder characterized by chorea, marked speech delay, and learning difficulties in 4 sisters from a consanguineous family. Methods: Whole-exome analysis of DNA of the 2 older patients followed by Sanger sequencing of the mutated exon in all family members. Results: A homozygous deleterious mutation, p.C291X, was identified in the GPR88 gene in both exome analyses. The mutation segregated with the disease in the family and was absent from a large cohort of controls. Conclusions: Homozygous deleterious mutation in GPR88 in humans is associated with marked speech delay, learning disabilities, and chorea, which manifest at 8–9 years of age. The finding is consistent with the reported abundant expression of GPR88 in the striatum and the hyperkinetic activity and learning impairment observed in GPR88 knockout mice. Although further functional characterization is needed, the finding underscores the importance of GPR88 in movement control and learning. PMID:27123486

  8. Accumulation of Deleterious Mutations on the Neo-Y Chromosome of Japan Sea Stickleback (Gasterosteus nipponicus).

    PubMed

    Yoshida, Kohta; Makino, Takashi; Kitano, Jun

    2017-01-01

    Degeneration of Y chromosomes is a common evolutionary path of XY sex chromosome systems. Recent genomic studies in flies and plants have revealed that even young neo-sex chromosomes with the age of a few million years show signs of Y degeneration, such as the accumulation of nonsense and frameshift mutations. However, it remains unclear whether neo-Y chromosomes also show rapid degeneration in fishes, which often have homomorphic sex chromosomes. Here, we investigated whether a neo-Y chromosome of Japan Sea stickleback (Gasterosteus nipponicus), which was formed by a Y-autosome fusion within the last 2 million years, accumulates deleterious mutations. Our previous genomic analyses did not detect excess nonsense and frameshift mutations on the Japan Sea stickleback neo-Y. In the present study, we found that the nonrecombining region of the neo-Y near the fusion end has accumulated nonsynonymous mutations altering amino acids of evolutionarily highly conserved residues. Enrichment of gene ontology terms related to protein phosphorylation and cellular protein modification process was found in the genes with potentially deleterious mutations on the neo-Y. These results suggest that the neo-Y of the Japan Sea stickleback has already accumulated mutations that may impair protein functions.

  9. Predicting the impact of deleterious single point mutations in SMAD gene family using structural bioinformatics approach.

    PubMed

    George Priya Doss, C; Nagasundaram, N; Tanwar, Himani

    2012-06-01

    Functional alteration in SMAD proteins leads to dis-regulation of its mechanism results in possibilities of high risk diseases like fibrosis, cancer, juvenile polyposis etc. Studying single nucleotide polymorphism (SNP) in SMAD genes helps understand the malfunction of these proteins. In this study, we focused on deleterious effects of nsSNPs in both structural and functional level using publically available bioinformatics tools. We have mainly focused on identifying deleterious nsSNPs in both structural and functional level in SMAD genes by using SIFT, PolyPhen, SNPs&GO, I-Mutant 3.0, MUpro and PANTHER. Structure analysis was carried out with the major mutation that occurred in the native protein coded by SMAD genes and its amino acid positions (R358W, K306S, R310G, S433R and R361C). SRide was used to check the stability of the native and mutant modelled proteins. In addition, we used MAPPER to identify SNPs present in transcription factor binding sites. These findings demonstrate that the in silico approaches can be used efficiently to identify potential candidate SNPs in large scale analysis.

  10. Profiling deleterious non-synonymous SNPs of smoker's gene CYP1A1.

    PubMed

    Ramesh, A Sai; Khan, Imran; Farhan, Md; Thiagarajan, Padma

    2013-01-01

    CYP1A1 gene belongs to the cytochrome P450 family and is known better as smokers' gene due to its hyperactivation as a consequence of long term smoking. The expression of CYP1A1 induces polycyclic aromatic hydrocarbon production in the lungs, which when over expressed, is known to cause smoking related diseases, such as cardiovascular pathologies, cancer, and diabetes. Single nucleotide polymorphisms (SNPs) are the simplest form of genetic variations that occur at a higher frequency, and are denoted as synonymous and non-synonymous SNPs on the basis of their effects on the amino acids. This study adopts a systematic in silico approach to predict the deleterious SNPs that are associated with disease conditions. It is inferred that four SNPs are highly deleterious, among which the SNP with rs17861094 is commonly predicted to be harmful by all tools. Hydrophobic (isoleucine) to hydrophilic (serine) amino acid variation was observed in the candidate gene. Hence, this investigation aims to characterize a candidate gene from 159 SNPs of CYP1A1.

  11. Deleterious effects of recombination and possible nonrecombinatorial advantages of sex in a fungal model.

    PubMed

    López-Villavicencio, M; Debets, A J M; Slakhorst, M; Giraud, T; Schoustra, S E

    2013-09-01

    Why sexual reproduction is so prevalent in nature remains a major question in evolutionary biology. Most of the proposed advantages of sex rely on the benefits obtained from recombination. However, it is still unclear whether the conditions under which these recombinatorial benefits would be sufficient to maintain sex in the short term are met in nature. Our study addresses a largely overlooked hypothesis, proposing that sex could be maintained in the short term by advantages due to functions linked with sex, but not related to recombination. These advantages would be so essential that sex could not be lost in the short term. Here, we used the fungus Aspergillus nidulans to experimentally test predictions of this hypothesis. Specifically, we were interested in (i) the short-term deleterious effects of recombination, (ii) possible nonrecombinatorial advantages of sex particularly through the elimination of mutations and (iii) the outcrossing rate under choice conditions in a haploid fungus able to reproduce by both outcrossing and haploid selfing. Our results were consistent with our hypotheses: we found that (i) recombination can be strongly deleterious in the short term, (ii) sexual reproduction between individuals derived from the same clonal lineage provided nonrecombinatorial advantages, likely through a selection arena mechanism, and (iii) under choice conditions, outcrossing occurs in a homothallic species, although at low rates.

  12. Joint Prediction of the Effective Population Size and the Rate of Fixation of Deleterious Mutations.

    PubMed

    Santiago, Enrique; Caballero, Armando

    2016-11-01

    Mutation, genetic drift, and selection are considered the main factors shaping genetic variation in nature. There is a lack, however, of general predictions accounting for the mutual interrelation between these factors. In the context of the background selection model, we provide a set of equations for the joint prediction of the effective population size and the rate of fixation of deleterious mutations, which are applicable both to sexual and asexual species. For a population of N haploid individuals and a model of deleterious mutations with effect s appearing with rate U in a genome L Morgans long, the asymptotic effective population size (Ne) and the average number of generations (T) between consecutive fixations can be approximated by [Formula: see text] and [Formula: see text] The solution is applicable to Muller's ratchet, providing satisfactory approximations to the rate of accumulation of mutations for a wide range of parameters. We also obtain predictions of the effective size accounting for the expected nucleotide diversity. Predictions for sexual populations allow for outlining the general conditions where mutational meltdown occurs. The equations can be extended to any distribution of mutational effects and the consideration of hotspots of recombination, showing that Ne is rather insensitive and not proportional to changes in N for many combinations of parameters. This could contribute to explain the observed small differences in levels of polymorphism between species with very different census sizes.

  13. Accumulation of Deleterious Passenger Mutations Is Associated with the Progression of Hepatocellular Carcinoma

    PubMed Central

    d’Avigdor, William M. H.; McCaughan, Geoffrey W.; Luciani, Fabio; Shackel, Nicholas A.

    2016-01-01

    In hepatocellular carcinoma (HCC), somatic genome-wide DNA mutations are numerous, universal and heterogeneous. Some of these somatic mutations are drivers of the malignant process but the vast majority are passenger mutations. These passenger mutations can be deleterious to individual protein function but are tolerated by the cell or are offset by a survival advantage conferred by driver mutations. It is unknown if these somatic deleterious passenger mutations (DPMs) develop in the precancerous state of cirrhosis or if it is confined to HCC. Therefore, we studied four whole-exome sequencing datasets, including patients with non-cirrhotic liver (n = 12), cirrhosis without HCC (n = 6) and paired HCC with surrounding non-HCC liver (n = 74 paired samples), to identify DPMs. After filtering out putative germline mutations, we identified 187±22 DPMs per non-diseased tissue. DPMs number was associated with liver disease progressing to HCC, independent of the number of exonic mutations. Tumours contained significantly more DPMs compared to paired non-tumour tissue (258–293 per HCC exome). Cirrhosis- and HCC-associated DPMs do not occur predominantly in specific genes, chromosomes or biological pathways and the effect on tumour biology is presently unknown. Importantly, for the first time we have shown a significant increase in DPMs with HCC. PMID:27631787

  14. Materialism.

    PubMed

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website.

  15. Additive genetic breeding values correlate with the load of partially deleterious mutations.

    PubMed

    Tomkins, Joseph L; Penrose, Marissa A; Greeff, Johan; LeBas, Natasha R

    2010-05-14

    The mutation-selection-balance model predicts most additive genetic variation to arise from numerous mildly deleterious mutations of small effect. Correspondingly, "good genes" models of sexual selection and recent models for the evolution of sex are built on the assumption that mutational loads and breeding values for fitness-related traits are correlated. In support of this concept, inbreeding depression was negatively genetically correlated with breeding values for traits under natural and sexual selection in the weevil Callosobruchus maculatus. The correlations were stronger in males and strongest for condition. These results confirm the role of existing, partially recessive mutations in maintaining additive genetic variation in outbred populations, reveal the nature of good genes under sexual selection, and show how sexual selection can offset the cost of sex.

  16. Covert deformed wing virus infections have long-term deleterious effects on honeybee foraging and survival.

    PubMed

    Benaets, Kristof; Van Geystelen, Anneleen; Cardoen, Dries; De Smet, Lina; de Graaf, Dirk C; Schoofs, Liliane; Larmuseau, Maarten H D; Brettell, Laura E; Martin, Stephen J; Wenseleers, Tom

    2017-02-08

    Several studies have suggested that covert stressors can contribute to bee colony declines. Here we provide a novel case study and show using radiofrequency identification tracking technology that covert deformed wing virus (DWV) infections in adult honeybee workers seriously impact long-term foraging and survival under natural foraging conditions. In particular, our experiments show that adult workers injected with low doses of DWV experienced increased mortality rates, that DWV caused workers to start foraging at a premature age, and that the virus reduced the workers' total activity span as foragers. Altogether, these results demonstrate that covert DWV infections have strongly deleterious effects on honeybee foraging and survival. These results are consistent with previous studies that suggested DWV to be an important contributor to the ongoing bee declines in Europe and the USA. Overall, our study underlines the strong impact that covert pathogen infections can have on individual and group-level performance in bees.

  17. Genome-wide Polygenic Burden of Rare Deleterious Variants in Sudden Unexpected Death in Epilepsy

    PubMed Central

    Leu, Costin; Balestrini, Simona; Maher, Bridget; Hernández-Hernández, Laura; Gormley, Padhraig; Hämäläinen, Eija; Heggeli, Kristin; Schoeler, Natasha; Novy, Jan; Willis, Joseph; Plagnol, Vincent; Ellis, Rachael; Reavey, Eleanor; O'Regan, Mary; Pickrell, William O.; Thomas, Rhys H.; Chung, Seo-Kyung; Delanty, Norman; McMahon, Jacinta M.; Malone, Stephen; Sadleir, Lynette G.; Berkovic, Samuel F.; Nashef, Lina; Zuberi, Sameer M.; Rees, Mark I.; Cavalleri, Gianpiero L.; Sander, Josemir W.; Hughes, Elaine; Helen Cross, J.; Scheffer, Ingrid E.; Palotie, Aarno; Sisodiya, Sanjay M.

    2015-01-01

    Sudden unexpected death in epilepsy (SUDEP) represents the most severe degree of the spectrum of epilepsy severity and is the commonest cause of epilepsy-related premature mortality. The precise pathophysiology and the genetic architecture of SUDEP remain elusive. Aiming to elucidate the genetic basis of SUDEP, we analysed rare, protein-changing variants from whole-exome sequences of 18 people who died of SUDEP, 87 living people with epilepsy and 1479 non-epilepsy disease controls. Association analysis revealed a significantly increased genome-wide polygenic burden per individual in the SUDEP cohort when compared to epilepsy (P = 5.7 × 10− 3) and non-epilepsy disease controls (P = 1.2 × 10− 3). The polygenic burden was driven both by the number of variants per individual, and over-representation of variants likely to be deleterious in the SUDEP cohort. As determined by this study, more than a thousand genes contribute to the observed polygenic burden within the framework of this study. Subsequent gene-based association analysis revealed five possible candidate genes significantly associated with SUDEP or epilepsy, but no one single gene emerges as common to the SUDEP cases. Our findings provide further evidence for a genetic susceptibility to SUDEP, and suggest an extensive polygenic contribution to SUDEP causation. Thus, an overall increased burden of deleterious variants in a highly polygenic background might be important in rendering a given individual more susceptible to SUDEP. Our findings suggest that exome sequencing in people with epilepsy might eventually contribute to generating SUDEP risk estimates, promoting stratified medicine in epilepsy, with the eventual aim of reducing an individual patient's risk of SUDEP. PMID:26501104

  18. Outcome of triple-negative breast cancer in patients with or without deleterious BRCA mutations

    PubMed Central

    Bayraktar, Soley; Gutierrez-Barrera, Angelica M.; Liu, Diane; Tasbas, Tunc; Akar, Ugur; Litton, Jennifer K.; Lin, E.; Albarracin, Constance T.; Meric-Bernstam, Funda; Gonzalez-Angulo, Ana M.; Hortobagyi, Gabriel N.

    2015-01-01

    More than 75% of breast cancers that develop in BRCA1 mutation carriers are triple-negative breast cancers (TNBC). The aim of this study was to compare the recurrence-free survival (RFS) and overall survival (OS) in high-risk patients with TNBC with and without deleterious BRCA1/2 mutations. A total of 227 women with TNBC who were referred for genetic counseling and underwent BRCA genetic testing between 1997 and 2010 were included in the study. The relationships between clinical variables and outcomes were evaluated using univariate and multivariate Cox proportional hazard regression models. Of 227 high-risk women with TNBC, 50% (n = 114) tested positive for BRCA1/2 mutations. Age, race, and tumor characteristics did not differ between BRCA non-carriers and carriers. At a median follow-up of 3.4 years, the 5-year RFS rates were 74 and 81% (P = 0.21), and 5-year OS rates were 85 and 93% in BRCA non-carriers and BRCA carriers, respectively (P = 0.11). In a multivariate model, after adjusting for age and disease stage, BRCA carriers tended to have a decreased risk of recurrence (HR = 0.67; 95% CI: 0.38–1.19; P = 0.17) or death (HR = 0.51; 95% CI:0.23–1.17; P = 0.11) compared to non-carriers. Our data indicate a 50% prevalence of deleterious BRCA1/2 mutations in high-risk women diagnosed with TNBC. Overall prognosis of TNBC in BRCA carriers and non-carriers is not significantly different within the first 5 years following an initial diagnosis. Further studies need to evaluate whether different therapies will change the outcome in these subgroups of TNBC. PMID:21830012

  19. Intestinal nutrient absorption - A biomarker for deleterious heavy metals in aquatic environments

    SciTech Connect

    Farmanfarmaian, A. )

    1988-09-01

    The deleterious effects of heavy metals on absorptive processes at the membrane surface will be summarized. Among the deleterious heavy metal chlorides (HgCl{sub 2}, CH{sub 3}HgCl, CdCl{sub 2}, CoCl{sub 2}, SrCl{sub 2}) tested HgCl{sub 2}, CH{sub 3}HgCl, and CdCl{sub 2} inhibit the absorption of several amino acids and sugars (L-leucine, L-methionine, L-isoleucine, L-lysine, cyclolencine, D-glucose, and D-galactose). The dose dependent inhibition of L-leucine uptake by HgCl{sub 2} is shown in a number of fish from different collection sites representing nektonic plankton feeders as well as demersal carnivores. The same type of data is shown for both HgCl{sub 2} and HC{sub 3}HgCl in the case of the commercially important summer flounder. Since the overall rate of intestinal absorption of amino acids and sugars involves the three processes of simple diffusion, protein-mediated facilitated diffusions, and protein-mediated sodium dependent active transport, the inhibition of the overall rate may not be sensitive enough as a biomarker. However, the active component, which alone accumulates essential amino acids in the tissue, appears to be very sensitive and can be used as a biomarker. The terminal tissue-to-medium (T/M) ratio of L-leucine concentration shows a 2-3 fold accumulation in the absence of mercury. Since the diffusional components can at best equilibrate L-leucine across the membrane % inhibition of the active component can be calculated after subtracting 1 from the experimental T/M values. The resulting inhibition is very sever ranging from approximately 50-100% for HgCl{sub 2} and 20-70% for CH{sub 3}HgCl over a range of 5-20 ppm of mercury.

  20. TNF and its receptors in the CNS: The essential, the desirable and the deleterious effects.

    PubMed

    Probert, L

    2015-08-27

    Tumor necrosis factor (TNF) is the prototypic pro-inflammatory cytokine. It is central to host defense and inflammatory responses but under certain circumstances also triggers cell death and tissue degeneration. Its pleiotropic effects often lead to opposing outcomes during the development of immune-mediated diseases, particularly those affecting the central nervous system (CNS). The reported contradictions may result from lack of precision in discussing TNF. TNF signaling comprises at minimum a two-ligand (soluble and transmembrane TNF) and two-receptor (TNFR1 and TNFR2) system, with ligands and receptors both differentially expressed and regulated on different cell types. The "functional multiplicity" this engenders is the focus of much research, but there is still no general consensus on functional outcomes of TNF signaling in general, let alone in the CNS. In this review, evidence showing the effects of TNF in the CNS under physiological and pathophysiological conditions is placed in the context of major advances in understanding of the cellular and molecular mechanisms that govern TNF function in general. Thus the roles of TNF signaling in the CNS shift from the conventional dichotomy of beneficial and deleterious, that mainly explain effects under pathological conditions, to incorporate a growing number of "essential" and "desirable" roles for TNF and its main cellular source in the CNS, microglia, under physiological conditions including regulation of neuronal activity and maintenance of myelin. An improved holistic view of TNF function in the CNS might better reconcile the expansive experimental data with stark clinical evidence that reduced functioning of TNF and its dominant pro-inflammatory receptor, TNFR1, are risk factors for the development of multiple sclerosis. It will also facilitate the safe translation of basic research findings from animal models to humans and propel the development of more selective anti-TNF therapies aimed at selectively

  1. Methylphenidate and environmental enrichment ameliorate the deleterious effects of prenatal stress on attention functioning.

    PubMed

    Zubedat, Salman; Aga-Mizrachi, Shlomit; Cymerblit-Sabba, Adi; Ritter, Ami; Nachmani, Maayan; Avital, Avi

    2015-01-01

    Either pre- or post-natal environmental factors seem to play a key role in brain and behavioral development and to exert long-term effects. Increasing evidence suggests that exposure to prenatal stress (PS) leads to motor and learning deficits and elevated anxiety, while enriched environment (EE) shows protective effects. The dopaminergic system is also sensitive to environmental life circumstances and affects attention functioning, which serves as the preliminary gate to cognitive processes. However, the effects of methylphenidate (MPH) on the dopaminergic system and attentional functioning, in the context of these life experiences, remain unclear. Therefore, we aimed to examine the effects of EE or PS on distinct types of attention, along with possible effects of MPH exposure. We found that PS impaired selective attention as well as partial sustained attention, while EE had beneficial effects. Both EE and MPH ameliorated the deleterious effects of PS on attention functioning. Considering the possible psychostimulant effect of MPH, we examined both anxiety-like behavior as well as motor learning. We found that PS had a clear anxiogenic effect, whereas EE had an anxiolytic effect. Nevertheless, the treatment with both MPH and/or EE recovered the deleterious effects of PS. In the motor-learning task, the PS group showed superior performance while MPH led to impaired motor learning. Performance decrements were prevented in both the PS + MPH and EE + MPH groups. This study provides evidence that peripubertal exposure to EE (by providing enhanced sensory, motor, and social opportunities) or MPH treatments might be an optional therapeutic intervention in preventing the PS long-term adverse consequences.

  2. Most of rare missense alleles in humans are deleterious:implications for evolution of complex disease and associationstudies

    SciTech Connect

    Kryukov, Gregory V.; Pennacchio, Len A.; Sunyaev, Shamil R.

    2006-10-24

    The accumulation of mildly deleterious missense mutations inindividual human genomes has been proposed to be a genetic basis forcomplex diseases. The plausibility of this hypothesis depends onquantitative estimates of the prevalence of mildly deleterious de novomutations and polymorphic variants in humans and on the intensity ofselective pressure against them. We combined analysis of mutationscausing human Mendelian diseases, human-chimpanzee divergence andsystematic data on human SNPs and found that about 20 percent of newmissense mutations in humans result in a loss of function, while about 27percent are effectively neutral. Thus, more than half of new missensemutations have mildly deleterious effects. These mutations give rise tomany low frequency deleterious allelic variants in the human populationas evident from a new dataset of 37 genes sequenced in over 1,500individual human chromosomes. Surprisingly, up to 70 percent of lowfrequency missense alleles are mildly deleterious and associated with aheterozygous fitness loss in the range 0.001-0.003. Thus, the low allelefrequency of an amino acid variant can by itself serve as a predictor ofits functional significance. Several recent studies have reported asignificant excess of rare missense variants in disease populationscompared to controls in candidate genes or pathways. These studies wouldbe unlikely to work if most rare variants were neutral or if rarevariants were not a significant contributor to the genetic component ofphenotypic inheritance. Our results provide a justification for thesetypes of candidate gene (pathway) association studies and imply thatmutation-selection balance may be a feasible mechanism for evolution ofsome common diseases.

  3. Deleterious alleles in the human genome are on average younger than neutral alleles of the same frequency.

    PubMed

    Kiezun, Adam; Pulit, Sara L; Francioli, Laurent C; van Dijk, Freerk; Swertz, Morris; Boomsma, Dorret I; van Duijn, Cornelia M; Slagboom, P Eline; van Ommen, G J B; Wijmenga, Cisca; de Bakker, Paul I W; Sunyaev, Shamil R

    2013-01-01

    Large-scale population sequencing studies provide a complete picture of human genetic variation within the studied populations. A key challenge is to identify, among the myriad alleles, those variants that have an effect on molecular function, phenotypes, and reproductive fitness. Most non-neutral variation consists of deleterious alleles segregating at low population frequency due to incessant mutation. To date, studies characterizing selection against deleterious alleles have been based on allele frequency (testing for a relative excess of rare alleles) or ratio of polymorphism to divergence (testing for a relative increase in the number of polymorphic alleles). Here, starting from Maruyama's theoretical prediction (Maruyama T (1974), Am J Hum Genet USA 6:669-673) that a (slightly) deleterious allele is, on average, younger than a neutral allele segregating at the same frequency, we devised an approach to characterize selection based on allelic age. Unlike existing methods, it compares sets of neutral and deleterious sequence variants at the same allele frequency. When applied to human sequence data from the Genome of the Netherlands Project, our approach distinguishes low-frequency coding non-synonymous variants from synonymous and non-coding variants at the same allele frequency and discriminates between sets of variants independently predicted to be benign or damaging for protein structure and function. The results confirm the abundance of slightly deleterious coding variation in humans.

  4. Age-associated molecular changes are deleterious and may modulate life span through diet

    PubMed Central

    Lee, Sang-Goo; Kaya, Alaattin; Avanesov, Andrei S.; Podolskiy, Dmitriy I.; Song, Eun Ju; Go, Du-Min; Jin, Gwi-Deuk; Hwang, Jae Yeon; Kim, Eun Bae; Kim, Dae-Yong; Gladyshev, Vadim N.

    2017-01-01

    Transition through life span is accompanied by numerous molecular changes, such as dysregulated gene expression, altered metabolite levels, and accumulated molecular damage. These changes are thought to be causal factors in aging; however, because they are numerous and are also influenced by genotype, environment, and other factors in addition to age, it is difficult to characterize the cumulative effect of these molecular changes on longevity. We reasoned that age-associated changes, such as molecular damage and tissue composition, may influence life span when used in the diet of organisms that are closely related to those that serve as a dietary source. To test this possibility, we used species-specific culture media and diets that incorporated molecular extracts of young and old organisms and compared the influence of these diets on the life span of yeast, fruitflies, and mice. In each case, the “old” diet or medium shortened the life span for one or both sexes. These findings suggest that age-associated molecular changes, such as cumulative damage and altered dietary composition, are deleterious and causally linked with aging and may affect life span through diet. PMID:28232953

  5. Blind Prediction of Deleterious Amino Acid Variations with SNPs&GO.

    PubMed

    Capriotti, Emidio; Martelli, Pier Luigi; Fariselli, Piero; Casadio, Rita

    2017-01-19

    SNPs&GO is a machine learning method for predicting the association of single amino acid variations (SAVs) to disease, considering protein functional annotation. The method is a binary classifier that implements a Support Vector Machine algorithm to discriminate between disease-related and neutral SAVs. SNPs&GO combines information from protein sequence with functional annotation encoded by Gene Ontology terms. Tested in sequence mode on more than 38,000 SAVs from the SwissVar dataset, our method reached 81% overall accuracy and an area under the receiving operating characteristic curve (AUC) of 0.88 with low false positive rate. In almost all the editions of the Critical Assessment of Genome Interpretation (CAGI) experiments, SNPs&GO ranked among the most accurate algorithms for predicting the effect of SAVs. In this paper we summarize the best results obtained by SNPs&GO on disease related variations of four CAGI challenges relative to the following genes: CHEK2 (CAGI 2010), RAD50 (CAGI 2011), p16-INK (CAGI 2013) and NAGLU (CAGI 2016). Result evaluation provides insights about the accuracy of our algorithm and the relevance of GO terms in annotating the effect of the variants. It also helps to define good practices for the detection of deleterious SAVs.

  6. Female rats are more susceptible to the deleterious effects of paradoxical sleep deprivation on cognitive performance.

    PubMed

    Hajali, Vahid; Sheibani, Vahid; Esmaeili-Mahani, Saeed; Shabani, Mohammad

    2012-03-17

    Paradoxical sleep deprivation (PSD) may alter subsequent learning and memory capacity. There are differences in both the intensity and direction of responses of the male and female species to the same environmental stimuli and experimental conditions. In the present study, we examined the extent of the effects of PSD for 72h on spatial learning and memory, anxiety-like behavior, corticosterone levels, and the body weight in male as well as in intact and ovariectomized (OVX) female Wistar rats. Multiple platform method was used for PSD induction. Spatial learning and memory and anxiety-like behavior were determined using Morris water maze (MWM) task and open field test, respectively. The data showed that PSD could not significantly affect subsequent spatial learning and short-term memory in male rats, while it significantly impaired the performance of the intact and OVX female rats. The PSD-intact and -OVX female rats showed more memory impairment than the PSD-male animals. Those impairments do not appear to be due to elevated stress level, since the plasma corticosterone did not significantly change following PSD induction. The open field data showed that PSD significantly reduced anxiety-like behavior in all experimental groups. In addition, PSD had a reducing effect on the mean body weight of female groups. Such results suggest that the female rats are more vulnerable to the deleterious effects of sleep loss on cognitive performance.

  7. Age-associated molecular changes are deleterious and may modulate life span through diet.

    PubMed

    Lee, Sang-Goo; Kaya, Alaattin; Avanesov, Andrei S; Podolskiy, Dmitriy I; Song, Eun Ju; Go, Du-Min; Jin, Gwi-Deuk; Hwang, Jae Yeon; Kim, Eun Bae; Kim, Dae-Yong; Gladyshev, Vadim N

    2017-02-01

    Transition through life span is accompanied by numerous molecular changes, such as dysregulated gene expression, altered metabolite levels, and accumulated molecular damage. These changes are thought to be causal factors in aging; however, because they are numerous and are also influenced by genotype, environment, and other factors in addition to age, it is difficult to characterize the cumulative effect of these molecular changes on longevity. We reasoned that age-associated changes, such as molecular damage and tissue composition, may influence life span when used in the diet of organisms that are closely related to those that serve as a dietary source. To test this possibility, we used species-specific culture media and diets that incorporated molecular extracts of young and old organisms and compared the influence of these diets on the life span of yeast, fruitflies, and mice. In each case, the "old" diet or medium shortened the life span for one or both sexes. These findings suggest that age-associated molecular changes, such as cumulative damage and altered dietary composition, are deleterious and causally linked with aging and may affect life span through diet.

  8. Lipoxidation adducts with peptides and proteins: deleterious modifications or signaling mechanisms?

    PubMed

    Domingues, Rosário M; Domingues, Pedro; Melo, Tânia; Pérez-Sala, Dolores; Reis, Ana; Spickett, Corinne M

    2013-10-30

    Protein lipoxidation refers to the modification by electrophilic lipid oxidation products to form covalent adducts, which for many years has been considered as a deleterious consequence of oxidative stress. Oxidized lipids or phospholipids containing carbonyl moieties react readily with lysine to form Schiff bases; alternatively, oxidation products containing α,β-unsaturated moieties are susceptible to nucleophilic attack by cysteine, histidine or lysine residues to yield Michael adducts, overall corresponding to a large number of possible protein adducts. The most common detection methods for lipoxidized proteins take advantage of the presence of reactive carbonyl groups to add labels, or use antibodies. These methods have limitations in terms of specificity and identification of the modification site. The latter question is satisfactorily addressed by mass spectrometry, which enables the characterization of the adduct structure. This has allowed the identification of lipoxidized proteins in physiological and pathological situations. While in many cases lipoxidation interferes with protein function, causing inhibition of enzymatic activity and increased immunogenicity, there are a small number of cases where lipoxidation results in gain of function or activity. For certain proteins lipoxidation may represent a form of redox signaling, although more work is required to confirm the physiological relevance and mechanisms of such processes. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine.

  9. Metformin reverts deleterious effects of advanced glycation end-products (AGEs) on osteoblastic cells.

    PubMed

    Schurman, L; McCarthy, A D; Sedlinsky, C; Gangoiti, M V; Arnol, V; Bruzzone, L; Cortizo, A M

    2008-06-01

    Advanced glycation endproducts (AGEs) are implicated in the complications of diabetes and ageing, affecting several tissues, including bone. Metformin, an insulin-sensitizer drug, reduces the risk of life-threatening macrovascular complications. We have evaluated the hypothesis that metformin can abrogate AGE-induced deleterious effects in osteoblastic cells in culture. In two osteoblast-like cell lines (UMR106 and MC3T3E1), AGE-modified albumin induced cell death, caspase-3 activity, altered intracellular oxidative stress and inhibited alkaline phosphatase activity. Metformin-treatment of osteoblastic cells prevented these AGE-induced alterations. We also assessed the expression of AGE receptors as a possible mechanism by which metformin could modulate the action of AGEs. AGEs-treatment of osteoblast-like cells enhanced RAGE protein expression, and this up-regulation was prevented in the presence of metformin. Although the precise mechanisms involved in metformin signaling are still elusive, our data implicate the AGE-RAGE interaction in the modulation of growth and differentiation of osteoblastic cells.

  10. Deleterious effects of maternal ingestion of cocoa upon fetal ductus arteriosus in late pregnancy

    PubMed Central

    Zielinsky, Paulo; Martignoni, Felipe V.; Vian, Izabele

    2014-01-01

    Cocoa powder has twice more antioxidants than red wine and three times more than green tea. Ten percent of its weight is made up of flavonoids. Cocoa has antioxidant and anti-inflammatory effects by downregulating cyclooxigenase-2 receptors expression in the endothelium and enhancing nitric oxide bioavailability. There are evidences that while polyphenols ingestion have cardioprotective effects in the adult, it may have deleterious effect on the fetus if ingested by the mother on the third trimester of pregnancy, causing intrauterine fetal ductus arteriosus (DA) constriction. Polyphenols present in many foods and their anti-inflammatory and antinociceptive activities have been shown to be as or more powerful than those of indomethacin. These effects are dependent on the inhibition of modulation of the arachidonic acid and the synthesis of prostaglandins, especially E-2, which is responsible for fetal DA patency. So, we hypothesized that this same mechanism is responsible for the harmful effect of polyphenol-rich foods, such as cocoa, upon the fetal DA after maternal intake of such substances in the third trimester of pregnancy, thereby rising the perspective of a note of caution for pregnant women diet. PMID:25566077

  11. Partition dataset according to amino acid type improves the prediction of deleterious non-synonymous SNPs

    SciTech Connect

    Yang, Jing; Li, Yuan-Yuan; Li, Yi-Xue; Ye, Zhi-Qiang

    2012-03-02

    Highlights: Black-Right-Pointing-Pointer Proper dataset partition can improve the prediction of deleterious nsSNPs. Black-Right-Pointing-Pointer Partition according to original residue type at nsSNP is a good criterion. Black-Right-Pointing-Pointer Similar strategy is supposed promising in other machine learning problems. -- Abstract: Many non-synonymous SNPs (nsSNPs) are associated with diseases, and numerous machine learning methods have been applied to train classifiers for sorting disease-associated nsSNPs from neutral ones. The continuously accumulated nsSNP data allows us to further explore better prediction approaches. In this work, we partitioned the training data into 20 subsets according to either original or substituted amino acid type at the nsSNP site. Using support vector machine (SVM), training classification models on each subset resulted in an overall accuracy of 76.3% or 74.9% depending on the two different partition criteria, while training on the whole dataset obtained an accuracy of only 72.6%. Moreover, the dataset was also randomly divided into 20 subsets, but the corresponding accuracy was only 73.2%. Our results demonstrated that partitioning the whole training dataset into subsets properly, i.e., according to the residue type at the nsSNP site, will improve the performance of the trained classifiers significantly, which should be valuable in developing better tools for predicting the disease-association of nsSNPs.

  12. Malocclusion and deleterious oral habits among adolescents in a developing area in northeastern Brazil.

    PubMed

    Thomaz, Erika Bárbara Abreu Fonseca; Cangussu, Maria Cristina Teixeira; Assis, Ana Marlúcia Oliveira

    2013-01-01

    Although malocclusions represent a serious public health issue, there is insufficient information about this problem in adolescents in Brazil, especially in poorer areas. The purpose of this cross-sectional study was to estimate the prevalence of facial alterations, dental malocclusions, and deleterious oral habits (DOH) among adolescents in a developing area in northeastern Brazil and to test the hypothesis that the occurrence of DOH in infancy is associated with DOH during adolescence. The study included a probabilistic population-based sample of 2,060 Brazilian students aged 12-15 years. Facial characteristics (type of facial profile, facial symmetry, and passive lip sealing) and malocclusions (Angle and Dental Aesthetic Index, DAI) were evaluated. DOH in infancy and adolescence were evaluated by interviews with the parents and adolescents. Most adolescents presented with normal facial characteristics. The malocclusion prevalence (Angle) was 83%. The DAI ranged from 13 to 69 (mean ± SD: 25.9 ± 7.7). Orthodontic treatment was necessary in 45.1% of the sample. The most prevalent DOH in adolescents were nail biting, object biting, cheek/lip biting, and bruxism, which were associated with finger sucking during infancy (P < 0.05). We conclude that malocclusions and DOH are common among Brazilian adolescents and that finger sucking during infancy may be a good predictor of DOH occurrence during adolescence.

  13. Tattoo inks contain polycyclic aromatic hydrocarbons that additionally generate deleterious singlet oxygen.

    PubMed

    Regensburger, Johannes; Lehner, Karin; Maisch, Tim; Vasold, Rudolf; Santarelli, Francesco; Engel, Eva; Gollmer, Anita; König, Burkhard; Landthaler, Michael; Bäumler, Wolfgang

    2010-08-01

    In the past years, tattoos have become very popular worldwide, and millions of people have tattoos with mainly black colours. Black tattoo inks are usually based on soot, are not regulated and may contain hazardous polycyclic aromatic hydrocarbons (PAHs). Part of PAHs possibly stay lifelong in skin, absorb UV radiation and generate singlet oxygen, which may affect skin integrity. Therefore, we analysed 19 commercially available tattoo inks using HPLC and mass spectrometry. The total concentrations of PAHs in the different inks ranged from 0.14 to 201 microg/g tattoo ink. Benz(a)pyrene was found in four ink samples at a mean concentration of 0.3 +/- 0.2 microg/g. We also found high concentrations of phenol ranging from 0.2 to 385 microg/g tattoo ink. PAHs partly show high quantum yields of singlet oxygen (Phi(Delta)) in the range from 0.18 to 0.85. We incubated keratinocytes with extracts of different inks. Subsequent UVA irradiation decreased the mitochondrial activity of cells when the extracts contained PAHs, which sufficiently absorb UVA and show simultaneously high Phi(Delta) value. Tattooing with black inks entails an injection of substantial amounts of phenol and PAHs into skin. Most of these PAHs are carcinogenic and may additionally generate deleterious singlet oxygen inside the dermis when skin is exposed to UVA (e.g. solar radiation).

  14. Ursolic acid derivative ameliorates streptozotocin-induced diabestic bone deleterious effects in mice

    PubMed Central

    Yu, Su-Guo; Zhang, Cheng-Jie; Xu, Xiu-E; Sun, Ji-Hua; Zhang, Li; Yu, Peng-Fei

    2015-01-01

    Objective: This study was performed to investigate bone deteriorations of diabetic mice in response to the treatment of ursolic acid derivative (UAD). Methods: The biomarkers in serum and urine were measured, tibias were taken for the measurement on gene and protein expression and histomorphology analysis, and femurs were taken for the measurement on bone Ca and three-dimensional architecture of trabecular bone. Results: UAD showed a greater increase in bone Ca, BMD and significantly increased FGF-23 and OCN, reduced PTH and CTX in diabetic mice. UAD reversed STZ-induced trabecular deleterious effects and stimulated bone remodeling. The treatment of STZ group with UAD significantly elevated the ratio of OPG/RANKL. Moreover, insulin and IGF-1 showed a negative correlation with both FBG and Hb1Ac in STZ group. We attributed down-regulating the level of Hb1Ac in diabetic mice to that ursolic acid derivative could primely control blood sugar levels. After analyzing of two adipocyte markers, PPARγ and aP2, increased expression in the tibias of diabetic mice, and UAD could improve STZ-induced adipocyte dysfunction. Conclusions: These results demonstrated that UAD could ameliorate STZ-induced bone deterioration through improving adipocyte dysfunction and enhancing new bone formation and inhibiting absorptive function of osteoclast in the bone of diabetic mice. PMID:26097549

  15. Are There Deleterious Cardiac Effects of Acute and Chronic Endurance Exercise?

    PubMed

    Eijsvogels, Thijs M H; Fernandez, Antonio B; Thompson, Paul D

    2016-01-01

    Multiple epidemiological studies document that habitual physical activity reduces the risk of atherosclerotic cardiovascular disease (ASCVD), and most demonstrate progressively lower rates of ASCVD with progressively more physical activity. Few studies have included individuals performing high-intensity, lifelong endurance exercise, however, and recent reports suggest that prodigious amounts of exercise may increase markers for, and even the incidence of, cardiovascular disease. This review examines the evidence that extremes of endurance exercise may increase cardiovascular disease risk by reviewing the causes and incidence of exercise-related cardiac events, and the acute effects of exercise on cardiovascular function, the effect of exercise on cardiac biomarkers, including "myocardial" creatine kinase, cardiac troponins, and cardiac natriuretic peptides. This review also examines the effect of exercise on coronary atherosclerosis and calcification, the frequency of atrial fibrillation in aging athletes, and the possibility that exercise may be deleterious in individuals genetically predisposed to such cardiac abnormalities as long QT syndrome, right ventricular cardiomyopathy, and hypertrophic cardiomyopathy. This review is to our knowledge unique because it addresses all known potentially adverse cardiovascular effects of endurance exercise. The best evidence remains that physical activity and exercise training benefit the population, but it is possible that prolonged exercise and exercise training can adversely affect cardiac function in some individuals. This hypothesis warrants further examination.

  16. Rare deleterious mutations are associated with disease in bipolar disorder families

    PubMed Central

    Rao, Aliz R; Yourshaw, Michael; Christensen, Bryce; Nelson, Stanley F; Kerner, Berit

    2016-01-01

    Bipolar disorder (BD) is a common, complex, and heritable psychiatric disorder characterized by episodes of severe mood swings. The identification of rare, damaging genomic mutations in families with BD could inform about disease mechanisms and lead to new therapeutic interventions. To determine whether rare, damaging mutations shared identity-by-descent in families with BD could be associated with disease, exome sequencing was performed in multigenerational families of the NIMH BD Family Study followed by in silico functional prediction. Disease association and disease specificity was determined using 5 090 exomes from the Sweden-Schizophrenia (SZ) Population-Based Case-Control Exome Sequencing study. We identified 14 rare and likely deleterious mutations in 14 genes that were shared identity-by-descent among affected family members. The variants were associated with BD (p<0.05 after Bonferroni correction) and disease specificity was supported by the absence of the mutations in patients with SZ. In addition, we found rare, functional mutations in known causal genes for neuropsychiatric disorders including holoprosencephaly and epilepsy. Our results demonstrate that exome sequencing in multigenerational families with BD is effective in identifying rare genomic variants of potential clinical relevance and also disease modifiers related to coexisting medical conditions. Replication of our results and experimental validation are required before disease causation could be assumed. PMID:27725659

  17. Deleterious effects of obesity upon the hormonal and molecular mechanisms controlling spermatogenesis and male fertility.

    PubMed

    Davidson, Lien M; Millar, Kate; Jones, Celine; Fatum, Muhammad; Coward, Kevin

    2015-09-01

    Worldwide obesity rates have nearly doubled since 1980 and currently over 10% of the population is obese. In 2008, over 1.4 billion adults aged 20 years and older had a body mass index or BMI above a healthy weight and of these, over 200 million men and nearly 300 million women were obese. While obesity can have many ramifications upon adult life, one growing area of concern is that of reproductive capacity. Obesity affects male infertility by influencing the hypothalamic-pituitary-gonadal axis, thus causing detrimental effects upon spermatogenesis and subsequent fertility. In particular, evidence indicates that excess adipose tissue can alter the relative ratio of testosterone and oestrogen. Additional effects involve the homeostatic disruption of insulin, sex-hormone-binding-globulin, leptin and inhibin B, leading to diminished testosterone production and impairment to spermatogenesis. Aberrant spermatogenesis arising from obesity is associated with downstream changes in key semen parameters, defective sperm capacitation and binding, and deleterious effects on sperm chromatin structure. More recent investigations into trans-generational epigenetic inheritance further suggest that molecular changes in sperm that arise from obesity-related impaired spermatogenesis, such as modified sperm RNA levels, DNA methylation, protamination and histone acetylation, can impact upon the development of offspring. Here, we summarise our current understanding of how obesity exerts influence over spermatogenesis and subsequent fertility status, and make recommendations for future investigative research.

  18. Increased mitochondrial mutation frequency after an island colonization: positive selection or accumulation of slightly deleterious mutations?

    PubMed

    Hardouin, Emilie A; Tautz, Diethard

    2013-04-23

    Island colonizations are excellent models for studying early processes of evolution. We found in a previous study on mice that had colonized the sub-Antarctic Kerguelen Archipelago about 200 years ago that they were derived from a single founder lineage and that this showed an unexpectedly large number of new mutations in the mitochondrial D-loop. To assess whether positive selection has played a role in the emergence of these variants, we have obtained 16 full mitochondrial genome sequences from these mice. For comparison, we have compiled 57 mitochondrial genome sequences from laboratory inbred lines that became established about 100 years ago, also starting from a single founder lineage. We find that the island mice and the laboratory lines show very similar mutation frequencies and patterns. None of the patterns in the Kerguelen mice provides evidence for positive selection. We conclude that nearly neutral evolutionary processes that assume the presence of slightly deleterious variants can fully explain the patterns. This supports the notion of time-dependency of molecular evolution and provides a new calibration point. Based on the observed mutation frequency, we calculate an average evolutionary rate of 0.23 substitutions per site per Myr for the earliest time frame of divergence, which is about six times higher than the long-term rate of 0.037 substitutions per site per Myr.

  19. Rare deleterious variants in GRHL3 are associated with human spina bifida.

    PubMed

    Lemay, Philippe; De Marco, Patrizia; Emond, Alexandre; Spiegelman, Dan; Dionne-Laporte, Alexandre; Laurent, Sandra; Merello, Elisa; Accogli, Andrea; Rouleau, Guy A; Capra, Valeria; Kibar, Zoha

    2017-03-08

    Neural tube defects, including spina bifida, are among the most common birth defects caused by failure of neural tube closure during development. They have a complex etiology involving largely undetermined environmental and genetic factors. Previous studies in mouse models have implicated the transcription factor Grhl3 as an important factor in the pathogenesis of spina bifida. In the present study, we conducted a resequencing analysis of GRHL3 in a cohort of 233 familial and sporadic cases of spina bifida. We identified two novel truncating variants: one homozygous frameshift variant, p.Asp16Aspfs*10, in two affected siblings and one heterozygous intronic splicing variant, p.Ala318Glyfs*26. We also identified five missense variants, one of which was demonstrated to reduce the activation of gene targets in a luciferase reporter assay. With the previously identified p.Arg391Cys variant, eight variants were found in GRHL3. Comparison of the variant rate between our cohort and the ExAC database identified a significant enrichment of deleterious variants in GRHL3 in the whole gene and the transactivation region in spina bifida patients. These data provide strong evidence for a role of GRHL3 as a predisposing factor to spina bifida and will help dissect the complex etiology and pathogenic mechanisms of these malformations.

  20. Selective propagation of functional mitochondrial DNA during oogenesis restricts the transmission of a deleterious mitochondrial variant.

    PubMed

    Hill, Jahda H; Chen, Zhe; Xu, Hong

    2014-04-01

    Although mitochondrial DNA (mtDNA) is prone to mutation and few mtDNA repair mechanisms exist, crippling mitochondrial mutations are exceedingly rare. Recent studies have demonstrated strong purifying selection in the mouse female germline. However, the mechanisms underlying positive selection of healthy mitochondria remain to be elucidated. We visualized mtDNA replication during Drosophila melanogaster oogenesis, finding that mtDNA replication commenced before oocyte determination during the late germarium stage and was dependent on mitochondrial fitness. We isolated a temperature-sensitive lethal mtDNA allele, mt:CoI(T300I), which resulted in reduced mtDNA replication in the germarium at the restrictive temperature. Additionally, the frequency of the mt:CoI(T300I) allele in heteroplasmic flies was decreased, both during oogenesis and over multiple generations, at the restrictive temperature. Furthermore, we determined that selection against mt:CoI(T300I) overlaps with the timing of selective replication of mtDNA in the germarium. These findings establish a previously uncharacterized developmental mechanism for the selective amplification of wild-type mtDNA, which may be evolutionarily conserved to limit the transmission of deleterious mutations.

  1. Deleterious mutations of a claw keratin in multiple taxa of reptiles.

    PubMed

    Dalla Valle, Luisa; Benato, Francesca; Rossi, Chiara; Alibardi, Lorenzo; Tschachler, Erwin; Eckhart, Leopold

    2011-03-01

    We have recently shown that homologs of mammalian hair keratins are expressed in the claws of the green anole lizard, Anolis carolinensis. To test whether reptilian hair keratin homologs are functionally associated with claws, we investigated the conservation of the prototypical reptilian hair keratin homolog, hard acidic keratin 1 (HA1), in representative species from all main clades of reptiles. A complete cDNA of HA1 was cloned from the claw-forming epidermis of the lacertid lizard Podarcis sicula, and partial HA1 gene sequences could be amplified from genomic DNA of tuatara, lizards, gekkos, turtles, and crocodiles. In contrast, the HA1 gene of the limbless slow worm, Anguis fragilis, and of two species of turtles contained at least one deleterious mutation. Moreover, an HA1 gene was undetectable in the softshell turtle, snakes, and birds. Mapping the presence and absence of HA1 onto the phylogenetic tree of sauropsids suggested that the HA1 gene has been lost independently in several lineages of reptiles. The species distribution of HA1 is compatible with the hypothesis of a primary function of HA1 in claws but also shows that the formation of reptilian claws does not strictly depend on this keratin.

  2. Are There Deleterious Cardiac Effects of Acute and Chronic Endurance Exercise?

    PubMed Central

    Eijsvogels, Thijs M. H.; Fernandez, Antonio B.; Thompson, Paul D.

    2015-01-01

    Multiple epidemiological studies document that habitual physical activity reduces the risk of atherosclerotic cardiovascular disease (ASCVD), and most demonstrate progressively lower rates of ASCVD with progressively more physical activity. Few studies have included individuals performing high-intensity, lifelong endurance exercise, however, and recent reports suggest that prodigious amounts of exercise may increase markers for, and even the incidence of, cardiovascular disease. This review examines the evidence that extremes of endurance exercise may increase cardiovascular disease risk by reviewing the causes and incidence of exercise-related cardiac events, and the acute effects of exercise on cardiovascular function, the effect of exercise on cardiac biomarkers, including “myocardial” creatine kinase, cardiac troponins, and cardiac natriuretic peptides. This review also examines the effect of exercise on coronary atherosclerosis and calcification, the frequency of atrial fibrillation in aging athletes, and the possibility that exercise may be deleterious in individuals genetically predisposed to such cardiac abnormalities as long QT syndrome, right ventricular cardiomyopathy, and hypertrophic cardiomyopathy. This review is to our knowledge unique because it addresses all known potentially adverse cardiovascular effects of endurance exercise. The best evidence remains that physical activity and exercise training benefit the population, but it is possible that prolonged exercise and exercise training can adversely affect cardiac function in some individuals. This hypothesis warrants further examination. PMID:26607287

  3. Is the deleterious effect of cryotherapy on proprioception mitigated by exercise?

    PubMed

    Ribeiro, F; Moreira, S; Neto, J; Oliveira, J

    2013-05-01

    This study aimed to examine the acute effects of cryotherapy on knee position sense and to determine the time period necessary to normalize joint position sense when exercising after cryotherapy. 12 subjects visited the laboratory twice, once for cryotherapy followed by 30 min of exercise on a cycloergometer and once for cryotherapy followed by 30 min of rest. Sessions were randomly determined and separated by 48 h. Cryotherapy was applied in the form of ice bag, filled with 1 kg of crushed ice, for 20 min. Knee position sense was measured at baseline, after cryotherapy and every 5 min after cryotherapy removal until a total of 30 min. The main effect of cryotherapy was significant showing an increase in absolute (F7,154=43.76, p<0.001) and relative (F7,154=7.97, p<0.001) errors after cryotherapy. The intervention after cryotherapy (rest vs. exercise) revealed a significant main effect only for absolute error (F7,154=4.05, p<0.001), i.e., when subjects exercised after cryotherapy, the proprioceptive acuity reached the baseline values faster (10 min vs. 15 min). Our results indicated that the deleterious effect of cryotherapy on proprioception is mitigated by low intensity exercise, being the time necessary to normalize knee position sense reduced from 15 to 10 min.

  4. Rapid Detection of Rare Deleterious Variants by Next Generation Sequencing with Optional Microarray SNP Genotype Data.

    PubMed

    Watson, Christopher M; Crinnion, Laura A; Gurgel-Gianetti, Juliana; Harrison, Sally M; Daly, Catherine; Antanavicuite, Agne; Lascelles, Carolina; Markham, Alexander F; Pena, Sergio D J; Bonthron, David T; Carr, Ian M

    2015-09-01

    Autozygosity mapping is a powerful technique for the identification of rare, autosomal recessive, disease-causing genes. The ease with which this category of disease gene can be identified has greatly increased through the availability of genome-wide SNP genotyping microarrays and subsequently of exome sequencing. Although these methods have simplified the generation of experimental data, its analysis, particularly when disparate data types must be integrated, remains time consuming. Moreover, the huge volume of sequence variant data generated from next generation sequencing experiments opens up the possibility of using these data instead of microarray genotype data to identify disease loci. To allow these two types of data to be used in an integrated fashion, we have developed AgileVCFMapper, a program that performs both the mapping of disease loci by SNP genotyping and the analysis of potentially deleterious variants using exome sequence variant data, in a single step. This method does not require microarray SNP genotype data, although analysis with a combination of microarray and exome genotype data enables more precise delineation of disease loci, due to superior marker density and distribution.

  5. The Accumulation of Deleterious Mutations as a Consequence of Domestication and Improvement in Sunflowers and Other Compositae Crops.

    PubMed

    Renaut, Sebastien; Rieseberg, Loren H

    2015-09-01

    For populations to maintain optimal fitness, harmful mutations must be efficiently purged from the genome. Yet, under circumstances that diminish the effectiveness of natural selection, such as the process of plant and animal domestication, deleterious mutations are predicted to accumulate. Here, we compared the load of deleterious mutations in 21 accessions from natural populations and 19 domesticated accessions of the common sunflower using whole-transcriptome single nucleotide polymorphism data. Although we find that genetic diversity has been greatly reduced during domestication, the remaining mutations were disproportionally biased toward nonsynonymous substitutions. Bioinformatically predicted deleterious mutations affecting protein function were especially strongly over-represented. We also identify similar patterns in two other domesticated species of the sunflower family (globe artichoke and cardoon), indicating that this phenomenon is not due to idiosyncrasies of sunflower domestication or the sunflower genome. Finally, we provide unequivocal evidence that deleterious mutations accumulate in low recombining regions of the genome, due to the reduced efficacy of purifying selection. These results represent a conundrum for crop improvement efforts. Although the elimination of harmful mutations should be a long-term goal of plant and animal breeding programs, it will be difficult to weed them out because of limited recombination.

  6. In Silico profiling of deleterious amino acid substitutions of potential pathological importance in haemophlia A and haemophlia B

    PubMed Central

    2012-01-01

    Background In this study, instead of current biochemical methods, the effects of deleterious amino acid substitutions in F8 and F9 gene upon protein structure and function were assayed by means of computational methods and information from the databases. Deleterious substitutions of F8 and F9 are responsible for Haemophilia A and Haemophilia B which is the most common genetic disease of coagulation disorders in blood. Yet, distinguishing deleterious variants of F8 and F9 from the massive amount of nonfunctional variants that occur within a single genome is a significant challenge. Methods We performed an in silico analysis of deleterious mutations and their protein structure changes in order to analyze the correlation between mutation and disease. Deleterious nsSNPs were categorized based on empirical based and support vector machine based methods to predict the impact on protein functions. Furthermore, we modeled mutant proteins and compared them with the native protein for analysis of protein structure stability. Results Out of 510 nsSNPs in F8, 378 nsSNPs (74%) were predicted to be 'intolerant' by SIFT, 371 nsSNPs (73%) were predicted to be 'damaging' by PolyPhen and 445 nsSNPs (87%) as 'less stable' by I-Mutant2.0. In F9, 129 nsSNPs (78%) were predicted to be intolerant by SIFT, 131 nsSNPs (79%) were predicted to be damaging by PolyPhen and 150 nsSNPs (90%) as less stable by I-Mutant2.0. Overall, we found that I-Mutant which emphasizes support vector machine based method outperformed SIFT and PolyPhen in prediction of deleterious nsSNPs in both F8 and F9. Conclusions The models built in this work would be appropriate for predicting the deleterious amino acid substitutions and their functions in gene regulation which would be useful for further genotype-phenotype researches as well as the pharmacogenetics studies. These in silico tools, despite being helpful in providing information about the nature of mutations, may also function as a first-pass filter to

  7. Materials

    NASA Technical Reports Server (NTRS)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  8. Distributions of selectively constrained sites and deleterious mutation rates in the hominid and murid genomes.

    PubMed

    Eory, Lél; Halligan, Daniel L; Keightley, Peter D

    2010-01-01

    Protein-coding sequences make up only about 1% of the mammalian genome. Much of the remaining 99% has been long assumed to be junk DNA, with little or no functional significance. Here, we show that in hominids, a group with historically low effective population sizes, all classes of noncoding DNA evolve more slowly than ancestral transposable elements and so appear to be subject to significant evolutionary constraints. Under the nearly neutral theory, we expected to see lower levels of selective constraints on most sequence types in hominids than murids, a group that is thought to have a higher effective population size. We found that this is the case for many sequence types examined, the most extreme example being 5'UTRs, for which constraint in hominids is only about one-third that of murids. Surprisingly, however, we observed higher constraints for some sequence types in hominids, notably 4-fold sites, where constraint is more than twice as high as in murids. This implies that more than about one-fifth of mutations at 4-fold sites are effectively selected against in hominids. The higher constraint at 4-fold sites in hominids suggests a more complex protein-coding gene structure than murids and indicates that methods for detecting selection on protein-coding sequences (e.g., using the d(N)/d(S) ratio), with 4-fold sites as a neutral standard, may lead to biased estimates, particularly in hominids. Our constraint estimates imply that 5.4% of nucleotide sites in the human genome are subject to effective negative selection and that there are three times as many constrained sites within noncoding sequences as within protein-coding sequences. Including coding and noncoding sites, we estimate that the genomic deleterious mutation rate U = 4.2. The mutational load predicted under a multiplicative model is therefore about 99% in hominids.

  9. Origin and dynamics of admixture in Brazilians and its effect on the pattern of deleterious mutations.

    PubMed

    Kehdy, Fernanda S G; Gouveia, Mateus H; Machado, Moara; Magalhães, Wagner C S; Horimoto, Andrea R; Horta, Bernardo L; Moreira, Rennan G; Leal, Thiago P; Scliar, Marilia O; Soares-Souza, Giordano B; Rodrigues-Soares, Fernanda; Araújo, Gilderlanio S; Zamudio, Roxana; Sant Anna, Hanaisa P; Santos, Hadassa C; Duarte, Nubia E; Fiaccone, Rosemeire L; Figueiredo, Camila A; Silva, Thiago M; Costa, Gustavo N O; Beleza, Sandra; Berg, Douglas E; Cabrera, Lilia; Debortoli, Guilherme; Duarte, Denise; Ghirotto, Silvia; Gilman, Robert H; Gonçalves, Vanessa F; Marrero, Andrea R; Muniz, Yara C; Weissensteiner, Hansi; Yeager, Meredith; Rodrigues, Laura C; Barreto, Mauricio L; Lima-Costa, M Fernanda; Pereira, Alexandre C; Rodrigues, Maíra R; Tarazona-Santos, Eduardo

    2015-07-14

    While South Americans are underrepresented in human genomic diversity studies, Brazil has been a classical model for population genetics studies on admixture. We present the results of the EPIGEN Brazil Initiative, the most comprehensive up-to-date genomic analysis of any Latin-American population. A population-based genome-wide analysis of 6,487 individuals was performed in the context of worldwide genomic diversity to elucidate how ancestry, kinship, and inbreeding interact in three populations with different histories from the Northeast (African ancestry: 50%), Southeast, and South (both with European ancestry >70%) of Brazil. We showed that ancestry-positive assortative mating permeated Brazilian history. We traced European ancestry in the Southeast/South to a wider European/Middle Eastern region with respect to the Northeast, where ancestry seems restricted to Iberia. By developing an approximate Bayesian computation framework, we infer more recent European immigration to the Southeast/South than to the Northeast. Also, the observed low Native-American ancestry (6-8%) was mostly introduced in different regions of Brazil soon after the European Conquest. We broadened our understanding of the African diaspora, the major destination of which was Brazil, by revealing that Brazilians display two within-Africa ancestry components: one associated with non-Bantu/western Africans (more evident in the Northeast and African Americans) and one associated with Bantu/eastern Africans (more present in the Southeast/South). Furthermore, the whole-genome analysis of 30 individuals (42-fold deep coverage) shows that continental admixture rather than local post-Columbian history is the main and complex determinant of the individual amount of deleterious genotypes.

  10. Optical spectroscopy and prevention of deleterious cerebral vascular effects of ethanol by magnesium ions.

    PubMed

    Barbour, Randall L; Gebrewold, Asefa; Altura, Bella T; Altura, Burton M

    2002-06-28

    Previously, it has been suggested that acute ethanol (alcohol) administration can result in concentration-dependent vasoconstriction and decreased cerebral blood flow. Here, we present in vivo results using rapid (240 nm/min) optical backscatter measurements, with an intact cranial preparation in the rat, indicating that acute infusion of ethanol directly into the rat brain rapidly produces dose-dependent vasoconstriction of the cerebral microcirculation associated with a pronounced reduction in tissue blood content, pronounced rises in deoxyhemoglobin, significantly increased levels of reduced cytochrome oxidase and microvascular damage as the dose increases. Furthermore, we present in vivo experiments demonstrating the capability of magnesium ions (Mg(2+)) to attenuate and prevent these deleterious responses. Optical backscatter spectra (500-800 nm) were obtained by directing a single sending and receiving fiber to a portion of the left parietal cranium (in anesthetized rats), shaved to a translucent appearance to facilitate optical penetration. In the absence of added Mg(2+), infusion of a 10% solution of ethanol at 0.34 ml/min ( approximately 26.8 mg/min) produced prompt vasoconstriction as evidenced by a greater than 90% loss of oxyhemoglobin from the field-of-view and increases in levels of reduced cytochrome oxidase to between 50% and >90%. These effects were partially, to nearly completely, attenuated by the addition of MgCl(2) to the infusate containing added ethanol. Of special interest was the observation that attenuation of the vasoconstrictive effect of ethanol by Mg(2+) persisted despite a subsequent ethanol challenge without added Mg(2+). The results obtained demonstrate that, depending on dose, ethanol can produce prompt and severe vasoconstriction of the intact cerebral microcirculation and that infusion of moderate doses of Mg(2+) can largely attenuate and prevent this response. We conclude that appreciable, graded changes in cerebral cytochrome

  11. Extracellular localization of galectin-3 has a deleterious role in joint tissues.

    PubMed

    Janelle-Montcalm, Audrée; Boileau, Christelle; Poirier, Françoise; Pelletier, Jean-Pierre; Guévremont, Mélanie; Duval, Nicolas; Martel-Pelletier, Johanne; Reboul, Pascal

    2007-01-01

    In this study we examine the extracellular role of galectin-3 (gal-3) in joint tissues. Following intra-articular injection of gal-3 or vehicle in knee joints of mice, histological evaluation of articular cartilage and subchondral bone was performed. Further studies were then performed using human osteoarthritic (OA) chondrocytes and subchondral bone osteoblasts, in which the effect of gal-3 (0 to 10 microg/ml) was analyzed. Osteoblasts were incubated in the presence of vitamin D3 (50 nM), which is an inducer of osteocalcin, encoded by an osteoblast terminal differentiation gene. Genes of interest mainly expressed in either chondrocytes or osteoblasts were analyzed with real-time RT-PCR and enzyme immunoassays. Signalling pathways regulating osteocalcin were analyzed in the presence of gal-3. Intra-articular injection of gal-3 induced knee swelling and lesions in both cartilage and subchondral bone. On human OA chondrocytes, gal-3 at 1 microg/ml stimulated ADAMTS-5 expression in chondrocytes and, at higher concentrations (5 and 10 microg/ml), matrix metalloproteinase-3 expression. Experiments performed with osteoblasts showed a weak but bipolar effect on alkaline phosphatase expression: stimulation at 1 microg/ml or inhibition at 10 microg/ml. In the absence of vitamin D3, type I collagen alpha 1 chain expression was inhibited by 10 microg/ml of gal-3. The vitamin D3 induced osteocalcin was strongly inhibited in a dose-dependent manner in the presence of gal-3, at both the mRNA and protein levels. This inhibition was mainly mediated by phosphatidylinositol-3-kinase. These findings indicate that high levels of extracellular gal-3, which could be encountered locally during the inflammatory process, have deleterious effects in both cartilage and subchondral bone tissues.

  12. Origin and dynamics of admixture in Brazilians and its effect on the pattern of deleterious mutations

    PubMed Central

    Kehdy, Fernanda S. G.; Gouveia, Mateus H.; Machado, Moara; Magalhães, Wagner C. S.; Horimoto, Andrea R.; Horta, Bernardo L.; Moreira, Rennan G.; Leal, Thiago P.; Scliar, Marilia O.; Soares-Souza, Giordano B.; Rodrigues-Soares, Fernanda; Araújo, Gilderlanio S.; Zamudio, Roxana; Sant Anna, Hanaisa P.; Santos, Hadassa C.; Duarte, Nubia E.; Fiaccone, Rosemeire L.; Figueiredo, Camila A.; Silva, Thiago M.; Costa, Gustavo N. O.; Beleza, Sandra; Berg, Douglas E.; Cabrera, Lilia; Debortoli, Guilherme; Duarte, Denise; Ghirotto, Silvia; Gilman, Robert H.; Gonçalves, Vanessa F.; Marrero, Andrea R.; Muniz, Yara C.; Weissensteiner, Hansi; Yeager, Meredith; Rodrigues, Laura C.; Barreto, Mauricio L.; Lima-Costa, M. Fernanda; Pereira, Alexandre C.; Rodrigues, Maíra R.; Tarazona-Santos, Eduardo

    2015-01-01

    While South Americans are underrepresented in human genomic diversity studies, Brazil has been a classical model for population genetics studies on admixture. We present the results of the EPIGEN Brazil Initiative, the most comprehensive up-to-date genomic analysis of any Latin-American population. A population-based genome-wide analysis of 6,487 individuals was performed in the context of worldwide genomic diversity to elucidate how ancestry, kinship, and inbreeding interact in three populations with different histories from the Northeast (African ancestry: 50%), Southeast, and South (both with European ancestry >70%) of Brazil. We showed that ancestry-positive assortative mating permeated Brazilian history. We traced European ancestry in the Southeast/South to a wider European/Middle Eastern region with respect to the Northeast, where ancestry seems restricted to Iberia. By developing an approximate Bayesian computation framework, we infer more recent European immigration to the Southeast/South than to the Northeast. Also, the observed low Native-American ancestry (6–8%) was mostly introduced in different regions of Brazil soon after the European Conquest. We broadened our understanding of the African diaspora, the major destination of which was Brazil, by revealing that Brazilians display two within-Africa ancestry components: one associated with non-Bantu/western Africans (more evident in the Northeast and African Americans) and one associated with Bantu/eastern Africans (more present in the Southeast/South). Furthermore, the whole-genome analysis of 30 individuals (42-fold deep coverage) shows that continental admixture rather than local post-Columbian history is the main and complex determinant of the individual amount of deleterious genotypes. PMID:26124090

  13. Malarial pathocoenosis: beneficial and deleterious interactions between malaria and other human diseases

    PubMed Central

    Faure, Eric

    2014-01-01

    In nature, organisms are commonly infected by an assemblage of different parasite species or by genetically distinct parasite strains that interact in complex ways. Linked to co-infections, pathocoenosis, a term proposed by M. Grmek in 1969, refers to a pathological state arising from the interactions of diseases within a population and to the temporal and spatial dynamics of all of the diseases. In the long run, malaria was certainly one of the most important component of past pathocoenoses. Today this disease, which affects hundreds of millions of individuals and results in approximately one million deaths each year, is always highly endemic in over 20% of the world and is thus co-endemic with many other diseases. Therefore, the incidences of co-infections and possible direct and indirect interactions with Plasmodium parasites are very high. Both positive and negative interactions between malaria and other diseases caused by parasites belonging to numerous taxa have been described and in some cases, malaria may modify the process of another disease without being affected itself. Interactions include those observed during voluntary malarial infections intended to cure neuro-syphilis or during the enhanced activations of bacterial gastro-intestinal diseases and HIV infections. Complex relationships with multiple effects should also be considered, such as those observed during helminth infections. Moreover, reports dating back over 2000 years suggested that co- and multiple infections have generally deleterious consequences and analyses of historical texts indicated that malaria might exacerbate both plague and cholera, among other diseases. Possible biases affecting the research of etiological agents caused by the protean manifestations of malaria are discussed. A better understanding of the manner by which pathogens, particularly Plasmodium, modulate immune responses is particularly important for the diagnosis, cure, and control of diseases in human populations

  14. Review: Bucephalus minimus, a deleterious trematode parasite of cockles Cerastoderma spp.

    PubMed

    Magalhães, L; Freitas, R; de Montaudouin, X

    2015-04-01

    Trematodes are the most prevalent and abundant macroparasites in coastal waters. They display a complex life cycle with alternation of free-living and parasitic stages generally involving three host species. The most deleterious stage is in the first intermediate host (a mollusc) where the parasite penetrates as miracidium larvae and asexually multiplicates in sporocysts/rediae to provide cercariae larvae. However, due to basic low prevalence in ecosystems, this system remains difficult to study. Taking the example of the cockle (Cerastoderma edule), an exploited bivalve along North-Eastern Atlantic coasts, and Bucephalus minimus, its most prevalent parasite as first intermediate host, we summarised the 51 most relevant papers (1887-2015). Besides, a 16-year monthly monitoring was performed at Banc d'Arguin (Atlantic coast of France), and allowed to obtain a sufficient number of infected cockles (276 out of 5,420 individuals) in order to provide new information concerning this parasite/host system. Sporocysts (diameter 80-500 μm) and developing cercariae (length 300-500 μm) are not visible before cockle reaches 16-mm shell length and then prevalence increases with host size. Seasonality of infection was not observed but variation of prevalence was significant among years and negatively correlated to the temperature of the former year, which could correspond to the period of infection by miracidium. Seven other species of trematode were identified in cockles as second intermediate host. For six of them, metacercariae abundance per individual was 2 to 12 folds higher in B. minimus-infected cockles, exacerbating the potential negative impact on host. From the parasite point of view, metacercariae can be considered as hitchhikers, taking advantage of the abnormal migration of B. minimus-infected cockles to the sediment surface where they become more vulnerable to predators that are also the final hosts of many of these parasites.

  15. Multiple deleterious effects of experimentally aged sperm in a monogamous bird

    USGS Publications Warehouse

    White, J.; Wagner, R.H.; Helfenstein, F.; Hatch, Shyla A.; Mulard, Hervé; Naves, L.C.; Danchin, E.

    2008-01-01

    Sperm aging is known to be detrimental to reproductive performance. However, this apparently general phenomenon has seldom been studied in an evolutionary context. The negative impact of sperm aging on parental fitness should constitute a strong selective pressure for adaptations to avoid its effects. We studied the impact of sperm aging on black-legged kittiwakes (Rissa tridactyla), a monogamous seabird. Kittiwakes comprise a model system because (i) of evidence that females eject their mates' sperm to prevent fertilization by sperm that would be old and degraded by the time of fertilization and result in reduced reproductive performance and (ii) the lack of extra-pair fertilization in this species makes cryptic female choice an unlikely explanation of postcopulatory sperm ejection by females. We experimentally manipulated the age of the sperm fertilizing kittiwake eggs by fitting males with anti-insemination rings for variable periods of time preceding egg-laying. We found evidence that sperm aging negatively affected four sequential stages of reproduction: fertilization potential, rate of embryonic development, embryonic mortality, and chick condition at hatching. These results may be produced by a continuum of a single process of sperm aging that differentially affects various aspects of development, depending on the degree of damage incurred to the spermatozoa. The marked impact of sperm age on female fitness may thus drive postcopulatory sperm ejection by females. These results provide experimental evidence of deleterious effects of sperm aging on a nondomestic vertebrate, underlining its taxonomic generality and its potential to select for a wide array of adaptations. ?? 2008 by The National Academy of Sciences of the USA.

  16. Weakly Deleterious Mutations and Low Rates of Recombination Limit the Impact of Natural Selection on Bacterial Genomes

    SciTech Connect

    Price, Morgan N.; Arkin, Adam P.

    2015-12-15

    Free-living bacteria are usually thought to have large effective population sizes, and so tiny selective differences can drive their evolution. However, because recombination is infrequent, “background selection” against slightly deleterious alleles should reduce the effective population size (Ne) by orders of magnitude. For example, for a well-mixed population with 1012 individuals and a typical level of homologous recombination (r/m= 3, i.e., nucleotide changes due to recombination [r] occur at 3 times the mutation rate [m]), we predict that Ne is<107. An argument for high Ne values for bacteria has been the high genetic diversity within many bacterial “species,” but this diversity may be due to population structure: diversity across subpopulations can be far higher than diversity within a subpopulation, which makes it difficult to estimate Ne correctly. Given an estimate ofNe, standard population genetics models imply that selection should be sufficient to drive evolution if Ne ×s is >1, where s is the selection coefficient. We found that this remains approximately correct if background selection is occurring or when population structure is present. Overall, we predict that even for free-living bacteria with enormous populations, natural selection is only a significant force ifs is above 10-7 or so. Because bacteria form huge populations with trillions of individuals, the simplest theoretical prediction is that the better allele at a site would predominate even if its advantage was just 10-9 per generation. In other words, virtually every nucleotide would be at the local optimum in most individuals. A more

  17. Weakly Deleterious Mutations and Low Rates of Recombination Limit the Impact of Natural Selection on Bacterial Genomes

    DOE PAGES

    Price, Morgan N.; Arkin, Adam P.

    2015-12-15

    Free-living bacteria are usually thought to have large effective population sizes, and so tiny selective differences can drive their evolution. However, because recombination is infrequent, “background selection” against slightly deleterious alleles should reduce the effective population size (Ne) by orders of magnitude. For example, for a well-mixed population with 1012 individuals and a typical level of homologous recombination (r/m= 3, i.e., nucleotide changes due to recombination [r] occur at 3 times the mutation rate [m]), we predict that Ne is<107. An argument for high Ne values for bacteria has been the high genetic diversity within many bacterial “species,” but thismore » diversity may be due to population structure: diversity across subpopulations can be far higher than diversity within a subpopulation, which makes it difficult to estimate Ne correctly. Given an estimate ofNe, standard population genetics models imply that selection should be sufficient to drive evolution if Ne ×s is >1, where s is the selection coefficient. We found that this remains approximately correct if background selection is occurring or when population structure is present. Overall, we predict that even for free-living bacteria with enormous populations, natural selection is only a significant force ifs is above 10-7 or so. Because bacteria form huge populations with trillions of individuals, the simplest theoretical prediction is that the better allele at a site would predominate even if its advantage was just 10-9 per generation. In other words, virtually every nucleotide would be at the local optimum in most individuals. A more sophisticated theory considers that bacterial genomes have millions of sites each and selection events on these many sites could interfere with each other, so that only larger effects would be important. However, bacteria can exchange genetic material, and in principle, this exchange could eliminate the interference between the evolution of

  18. A novel deleterious PTEN mutation in a patient with early-onset bilateral breast cancer

    PubMed Central

    2014-01-01

    Background An early age at Breast Cancer (BC) onset may be a hallmark of inherited predisposition, but BRCA1/2 mutations are only found in a minority of younger BC patients. Among the others, a fraction may carry mutations in rarer BC genes, such as TP53, STK11, CDH1 and PTEN. As the identification of women harboring such mutations allows for targeted risk-management, the knowledge of associated manifestations and an accurate clinical and family history evaluation are warranted. Case presentation We describe the case of a woman who developed an infiltrating ductal carcinoma of the right breast at the age of 32, a contralateral BC at age 36 and another BC of the right breast at 40. When she was 39 years-old, during a dermatological examination, mucocutaneous features suggestive of Cowden Syndrome, a disorder associated to germ-line PTEN mutations, were noticed. PTEN genetic testing revealed the novel c.71A > T (p.Asp24Val) mutation, whose deleterious effect, suggested by conservation data and in silico tools, was definitely demonstrated by the incapacity of mutant PTEN to inhibit Akt phosphorylation when used to complement PTEN-null cells. In BC tissue, despite the absence of LOH or somatic mutations of PTEN, Akt phosphorylation was markedly increased in comparison to normal tissue, thus implying additional somatic events into the deregulation of the PI3K/Akt/mTOR pathway and, presumably, into carcinogenesis. Hence, known oncogenic mutations in PIK3CA (exons 10 and 21) and AKT1 (exon 2) were screened in tumor DNA with negative results, which suggests that the responsible somatic event(s) is a different, uncommon one. Conclusion This case stresses the importance of clinical/genetic assessment of early-onset BC patients in order to identify mutation carriers, who are at high risk of new events, so requiring tailored management. Moreover, it revealed a novel PTEN mutation with pathogenic effect, pointing out, however, the need for further efforts to elucidate the

  19. Juvenile idiopathic arthritis activity and function ability: deleterious effects in periodontal disease?

    PubMed

    Pugliese, Camila; van der Vinne, Roberta T A; Campos, Lucia M A; Guardieiro, Priscila R; Saviolli, Cynthia; Bonfá, Eloisa; Pereira, Rosa M R; Viana, Vilma S; Borba, Eduardo F; Silva, Clovis A

    2016-01-01

    provides additional evidence that increased activity and reduced functional ability underlies the deleterious effect of JIA in oral health.

  20. The deleterious effect of metabolic acidosis on nutritional status of hemodialysis patients.

    PubMed

    Soleymanian, Tayebeh; Ghods, Ahad

    2011-11-01

    One of the main causes of protein-energy malnutrition in patients on maintenance hemodialysis (MHD) is metabolic acidosis. The aim of this study was to evaluate the effect of metabolic acidosis on nutritional status in a group of MHD patients with adequately delivered dialysis treatment. Of 165 eligible anuric MHD outpatients with Kt/V ≥ 1 and no underlying inflammatory diseases, 47 subjects were enrolled. In order to evaluate the effect of different parameters on serum albumin, we measured the pre-dialysis serum albumin, blood pH, serum bicarbonate (HCO 3‾ ), Kt/V, normalized protein catabolic rate (nPCR) and body mass index (BMI) in these patients. The mean age of the study patients was 55 ± 13.8 years; there were 22 females and six diabetics. The average Kt/V was 1.22 ± 0.16, pH was 7.40 ± 0.15, serum HCO 3‾ was 23.18 ± 2.38 mEq/L, serum albumin was 4.03 ± 0.56 g/dL, nPCR was 1.00 ± 0.16 g/kg/day, post-dialysis body weight was 58.50 ± 11.50 kg and BMI was 23.47 ± 2.70 kg/m 2 . There was a statistically significant direct correlation between serum albumin and BMI (r = 0.415, P = 0.004), and between serum albumin and serum HCO 3 (r = 0.341, P = 0.019). On multiple regression analysis, the predictors of serum albumin were serum HCO3‾ and BMI (direct effect) and nPCR (inverse effect). In 17 patients on MHD with serum HCO3‾ <22 mEq/L, there was a significant inverse correlation between HCO 3 and nPCR (r = 0.492, P = 0.045), and these patients had significantly lower serum albumin compared with patients with serum HCO3‾ >22 mEq/L (P = 0.046). These data demonstrate that patients on MHD with metabolic acidosis had a lower serum albumin concentration despite adequate dialysis treatment. The inverse effect of nPCR on serum albumin concentration in acidotic MHD patients may be due to hypercatabolism in the setting of metabolic acidosis, leading to deleterious effects on the nutritional status of patients on MHD.

  1. Distinguishing between longevity and buffered-deleterious genotypes for exceptional human longevity: the case of the MTP gene.

    PubMed

    Huffman, Derek M; Deelen, Joris; Ye, Kenny; Bergman, Aviv; Slagboom, Eline P; Barzilai, Nir; Atzmon, Gil

    2012-11-01

    The single nucleotide polymorphism, rs2866164, in the MTP gene, has been associated with human longevity but has not been validated by subsequent longevity studies. Using our population of Ashkenazi Jews, we find that the MTP CC genotype is significantly overrepresented in centenarians and their offspring, as compared with controls (p < .05). However, when we examined MTP CC genotype frequency pattern with aging, we observed a monotonic decline between ages 55-85 years followed by a dramatic enrichment after age 90 years, forming a U-shape pattern (p < .05). Furthermore, the MTP CC genotype was buffered by three validated longevity genotypes (p < .05). This buffering effect was found to confer an enrichment of the MTP CC genotype in centenarians, whereas their absence in CC controls resulted in poorer survivorship (p < .05). Thus, we conclude that MTP CC is a buffered-deleterious genotype and that assessing genotype frequency across aging is essential for discerning longevity from buffered-deleterious genotypes.

  2. Minute doping with deleterious rare earths in YBa2Cu3O7-δ films for flux pinning enhancements

    NASA Astrophysics Data System (ADS)

    Barnes, P. N.; Kell, J. W.; Harrison, B. C.; Haugan, T. J.; Varanasi, C. V.; Rane, M.; Ramos, F.

    2006-07-01

    To enhance the critical current density of YBa2Cu3O7-δ films, flux pinning centers are intentionally added to inhibit flux flow in applied magnetic fields. Here we provide an initial demonstration that the incorporation of very minor additions (⩽1% of Y as opposed to the 10%-40% in standard substitutions) of typically deleterious rare earths into high quality YBa2Cu3O7-δ thin films provides significant improvement of the film's in-field current density. This is accomplished without reoptimization of the deposition parameters. Instead of site substitution for Y as might be expected, the deleterious rare earths potentially result in the formation of nanoparticulates.

  3. Additives to Prevent Deleterious Effects Associated with Long-Term Storage of Petroleum Products,

    DTIC Science & Technology

    1980-09-01

    source of carbon for bacteria than the fuel itself. When the material is used it must be protected by a bactericide . 50. Sulfate-reducing bacteria... Bactericides have been widely used to control microbial effects in petroleum storage. Most of these compounds dissolve in the petroleum product but, move into...the bactericides . Generally these materials would be deactivated by absorp- tion on particulates or oxidation. Testing of bactericides for use in long

  4. Vitamin E prevents deleterious effects of di (2-ethyl hexyl) phthalate, a plasticizer used in PVC blood storage bags.

    PubMed

    Dhanya, C R; Gayathri, N S; Mithra, K; Nair, K V Neelakantan; Kurup, P A

    2004-09-01

    Vitamin E administration prevented DEHP induced deleterious effects like (i) degenerative changes in the brain and thyroid, (ii) decrease in the activity of neuronal membrane Na+ - K+ ATPase, (iii) decrease in the concentration of insulin, cortisol and TSH, and (iv) the increase in T3 and T4 in female Albino rats. The results suggest use of vitamin E to prevent harmful effects of repeated transfusion of DEHP containing blood as in thalassemia patient. The possibility of using vitamin E to prevent the harmful effects of repeated transfusion of DEHP containing blood, as in thalassemia patients, is discussed.

  5. Duration of Sexual Harassment and Generalized Harassment in the Workplace Over Ten Years: Effects on Deleterious Drinking Outcomes

    PubMed Central

    McGinley, Meredith; Richman, Judith A.; Rospenda, Kathleen M.

    2012-01-01

    While harassment in the workplace has been linked to deleterious drinking outcomes, researchers have yet to examine the long-term effects of chronic workplace harassment. During a ten year longitudinal mail survey, university employees (N = 2265) were administered measures of sexual harassment, generalized workplace harassment, and problematic drinking. Using growth mixture modeling, two latent classes of workplace harassment emerged: infrequent and chronic. Demographic characteristics (gender, age, and race) predicted the shape of the trajectories and likelihood of class membership. As hypothesized, membership in the chronic harassment classes was linked to future problematic drinking, even after controlling for previous drinking. PMID:21745045

  6. Duration of sexual harassment and generalized harassment in the workplace over ten years: effects on deleterious drinking outcomes.

    PubMed

    McGinley, Meredith; Richman, Judith A; Rospenda, Kathleen M

    2011-01-01

    Although harassment in the workplace has been linked to deleterious drinking outcomes, researchers have yet to examine the long-term effects of chronic workplace harassment. During a 10-year longitudinal mail survey, university employees (N = 2,265) were administered measures of sexual harassment, generalized workplace harassment, and problematic drinking. Using growth mixture modeling, two latent classes of workplace harassment emerged: infrequent and chronic. Demographic characteristics (gender, age, and race) predicted the shape of the trajectories and likelihood of class membership. As hypothesized, membership in the chronic harassment classes was linked to future problematic drinking, even after controlling for previous drinking.

  7. The effects of a deleterious mutation load on patterns of influenza A/H3N2's antigenic evolution in humans.

    PubMed

    Koelle, Katia; Rasmussen, David A

    2015-09-15

    Recent phylogenetic analyses indicate that RNA virus populations carry a significant deleterious mutation load. This mutation load has the potential to shape patterns of adaptive evolution via genetic linkage to beneficial mutations. Here, we examine the effect of deleterious mutations on patterns of influenza A subtype H3N2's antigenic evolution in humans. By first analyzing simple models of influenza that incorporate a mutation load, we show that deleterious mutations, as expected, act to slow the virus's rate of antigenic evolution, while making it more punctuated in nature. These models further predict three distinct molecular pathways by which antigenic cluster transitions occur, and we find phylogenetic patterns consistent with each of these pathways in influenza virus sequences. Simulations of a more complex phylodynamic model further indicate that antigenic mutations act in concert with deleterious mutations to reproduce influenza's spindly hemagglutinin phylogeny, co-circulation of antigenic variants, and high annual attack rates.

  8. A deleterious Nav1.1 mutation selectively impairs telencephalic inhibitory neurons derived from Dravet Syndrome patients

    PubMed Central

    Sun, Yishan; Paşca, Sergiu P; Portmann, Thomas; Goold, Carleton; Worringer, Kathleen A; Guan, Wendy; Chan, Karen C; Gai, Hui; Vogt, Daniel; Chen, Ying-Jiun J; Mao, Rong; Chan, Karrie; Rubenstein, John LR; Madison, Daniel V; Hallmayer, Joachim; Froehlich-Santino, Wendy M; Bernstein, Jonathan A; Dolmetsch, Ricardo E

    2016-01-01

    Dravet Syndrome is an intractable form of childhood epilepsy associated with deleterious mutations in SCN1A, the gene encoding neuronal sodium channel Nav1.1. Earlier studies using human induced pluripotent stem cells (iPSCs) have produced mixed results regarding the importance of Nav1.1 in human inhibitory versus excitatory neurons. We studied a Nav1.1 mutation (p.S1328P) identified in a pair of twins with Dravet Syndrome and generated iPSC-derived neurons from these patients. Characterization of the mutant channel revealed a decrease in current amplitude and hypersensitivity to steady-state inactivation. We then differentiated Dravet-Syndrome and control iPSCs into telencephalic excitatory neurons or medial ganglionic eminence (MGE)-like inhibitory neurons. Dravet inhibitory neurons showed deficits in sodium currents and action potential firing, which were rescued by a Nav1.1 transgene, whereas Dravet excitatory neurons were normal. Our study identifies biophysical impairments underlying a deleterious Nav1.1 mutation and supports the hypothesis that Dravet Syndrome arises from defective inhibitory neurons. DOI: http://dx.doi.org/10.7554/eLife.13073.001 PMID:27458797

  9. Deleterious mutations in the essential mRNA metabolism factor, hGle1, in amyotrophic lateral sclerosis

    PubMed Central

    Kaneb, Hannah M.; Folkmann, Andrew W.; Belzil, Véronique V.; Jao, Li-En; Leblond, Claire S.; Girard, Simon L.; Daoud, Hussein; Noreau, Anne; Rochefort, Daniel; Hince, Pascale; Szuto, Anna; Levert, Annie; Vidal, Sabrina; André-Guimont, Catherine; Camu, William; Bouchard, Jean-Pierre; Dupré, Nicolas; Rouleau, Guy A.; Wente, Susan R.; Dion, Patrick A.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the selective death of motor neurons. Causative mutations in the global RNA-processing proteins TDP-43 and FUS among others, as well as their aggregation in ALS patients, have identified defects in RNA metabolism as an important feature in this disease. Lethal congenital contracture syndrome 1 and lethal arthrogryposis with anterior horn cell disease are autosomal recessive fetal motor neuron diseases that are caused by mutations in another global RNA-processing protein, hGle1. In this study, we carried out the first screening of GLE1 in ALS patients (173 familial and 760 sporadic) and identified 2 deleterious mutations (1 splice site and 1 nonsense mutation) and 1 missense mutation. Functional analysis of the deleterious mutants revealed them to be unable to rescue motor neuron pathology in zebrafish morphants lacking Gle1. Furthermore, in HeLa cells, both mutations caused a depletion of hGle1 at the nuclear pore where it carries out an essential role in nuclear export of mRNA. These results suggest a haploinsufficiency mechanism and point to a causative role for GLE1 mutations in ALS patients. This further supports the involvement of global defects in RNA metabolism in ALS. PMID:25343993

  10. Mutation accumulation in real branches: fitness assays for genomic deleterious mutation rate and effect in large-statured plants.

    PubMed

    Schultz, Stewart T; Scofield, Douglas G

    2009-08-01

    The genomic deleterious mutation rate and mean effect are central to the biology and evolution of all species. Large-statured plants, such as trees, are predicted to have high mutation rates due to mitotic mutation and the absence of a sheltered germ line, but their size and generation time has hindered genetic study. We develop and test approaches for estimating deleterious mutation rates and effects from viability comparisons within the canopy of large-statured plants. Our methods, inspired by E. J. Klekowski, are a modification of the classic Bateman-Mukai mutation-accumulation experiment. Within a canopy, cell lineages accumulate mitotic mutations independently. Gametes or zygotes produced at more distal points by these cell lineages contain more mitotic mutations than those at basal locations, and within-flower selfs contain more homozygous mutations than between-flower selfs. The resulting viability differences allow demonstration of lethal mutation with experiments similar in size to assays of genetic load and allow estimates of the rate and effect of new mutations with moderate precision and bias similar to that of classic mutation-accumulation experiments in small-statured organisms. These methods open up new possibilities with the potential to provide valuable new insights into the evolutionary genetics of plants.

  11. De novo, systemic, deleterious amino acid substitutions are common in large cytoskeleton-related protein coding regions

    PubMed Central

    Stoll, Rebecca J.; Thompson, Grace R.; Samy, Mohammad D.; Blanck, George

    2017-01-01

    Human mutagenesis is largely random, thus large coding regions, simply on the basis of probability, represent relatively large mutagenesis targets. Thus, we considered the possibility that large cytoskeletal-protein related coding regions (CPCRs), including extra-cellular matrix (ECM) coding regions, would have systemic nucleotide variants that are not present in common SNP databases. Presumably, such variants arose recently in development or in recent, preceding generations. Using matched breast cancer and blood-derived normal datasets from the cancer genome atlas, CPCR single nucleotide variants (SNVs) not present in the All SNPs(142) or 1000 Genomes databases were identified. Using the Protein Variation Effect Analyzer internet-based tool, it was discovered that apparent, systemic mutations (not shared among others in the analysis group) in the CPCRs, represented numerous deleterious amino acid substitutions. However, no such deleterious variants were identified among the (cancer blood-matched) variants shared by other members of the analysis group. These data indicate that private SNVs, which potentially have a medical consequence, occur de novo with significant frequency in the larger, human coding regions that collectively impact the cytoskeleton and ECM. PMID:28357075

  12. Methyl donor supplementation in rats reverses the deleterious effect of maternal separation on depression-like behaviour.

    PubMed

    Paternain, Laura; Martisova, Eva; Campión, Javier; Martínez, J Alfredo; Ramírez, Maria J; Milagro, Fermin I

    2016-02-15

    Adverse early life events are associated with altered stress responsiveness and metabolic disturbances in the adult life. Dietary methyl donor supplementation could be able to reverse the negative effects of maternal separation by affecting DNA methylation in the brain. In this study, maternal separation during lactation reduced body weight gain in the female adult offspring without affecting food intake, and altered total and HDL-cholesterol levels. Also, maternal separation induced a cognitive deficit as measured by NORT and an increase in the immobility time in the Porsolt forced swimming test, consistent with increased depression-like behaviour. An 18-week dietary supplementation with methyl donors (choline, betaine, folate and vitamin B12) from postnatal day 60 also reduced body weight without affecting food intake. Some of the deleterious effects induced by maternal separation, such as the abnormal levels of total and HDL-cholesterol, but especially the depression-like behaviour as measured by the Porsolt test, were reversed by methyl donor supplementation. Also, the administration of methyl donors increased total DNA methylation (measured by immunohistochemistry) and affected the expression of insulin receptor in the hippocampus of the adult offspring. However, no changes were observed in the DNA methylation status of insulin receptor and corticotropin-releasing hormone (CRH) promoter regions in the hypothalamus. In summary, methyl donor supplementation reversed some of the deleterious effects of an early life-induced model of depression in rats and altered the DNA methylation profile in the brain.

  13. Pulmonary exposure to cellulose nanocrystals caused deleterious effects to reproductive system in male mice.

    PubMed

    Farcas, Mariana T; Kisin, Elena R; Menas, Autumn L; Gutkin, Dmitriy W; Star, Alexander; Reiner, Richard S; Yanamala, Naveena; Savolainen, Kai; Shvedova, Anna A

    2016-01-01

    Over the past several years there has been an increased number of applications of cellulosic materials in many sectors, including the food industry, cosmetics, and pharmaceuticals. However, to date, there are few studies investigating the potential adverse effects of cellulose nanocrystals (CNC). The objective of this study was to determine long-term outcomes on the male reproductive system of mice upon repeated pharyngeal aspiration exposure to CNC. To achieve this, cauda epididymal sperm samples were analyzed for sperm concentration, motility, morphological abnormalities, and DNA damage. Testicular and epididymal oxidative damage was evaluated, as well as histopathology examination of testes. In addition, changes in levels of testosterone in testes and serum and of luteinizing hormone (LH) in serum were determined. Three months after the last administration, CNC exposure significantly altered sperm concentration, motility, cell morphology, and sperm DNA integrity. These parameters correlated with elevated proinflammatory cytokines levels and myeloperoxidase (MPO) activity in testes, as well as oxidative stress in both testes and epididymis. Exposure to CNC also produced damage to testicular structure, as evidenced by presence of interstitial edema, frequent dystrophic seminiferous tubules with arrested spermatogenesis and degenerating spermatocytes, and imbalance in levels of testosterone and LH. Taken together, these results demonstrate that pulmonary exposure to CNC induces sustained adverse effects in spermatocytes/spermatozoa, suggesting male reproductive toxicity.

  14. A new approach to tag design in dolphin telemetry: Computer simulations to minimise deleterious effects

    NASA Astrophysics Data System (ADS)

    Pavlov, V. V.; Wilson, R. P.; Lucke, K.

    2007-02-01

    Remote-sensors and transmitters are powerful devices for studying cetaceans at sea. However, despite substantial progress in microelectronics and miniaturisation of systems, dolphin tags are imperfectly designed; additional drag from tags increases swim costs, compromises swimming capacity and manoeuvrability, and leads to extra loads on the animal's tissue. We propose a new approach to tag design, elaborating basic principles and incorporating design stages to minimise device effects by using computer-aided design. Initially, the operational conditions of the device are defined by quantifying the shape, hydrodynamics and range of the natural deformation of the dolphin body at the tag attachment site (such as close to the dorsal fin). Then, parametric models of both of the dorsal fin and a tag are created using the derived data. The link between parameters of the fin and a tag model allows redesign of tag models according to expected changes of fin geometry (difference in fin shape related with species, sex, and age peculiarities, simulation of the bend of the fin during manoeuvres). A final virtual modelling stage uses iterative improvement of a tag model in a computer fluid dynamics (CFD) environment to enhance tag performance. This new method is considered as a suitable tool of tag design before creation of the physical model of a tag and testing with conventional wind/water tunnel technique. Ultimately, tag materials are selected to conform to the conditions identified by the modelling process and thus help create a physical model of a tag, which should minimise its impact on the animal carrier and thus increase the reliability and quality of the data obtained.

  15. The role of aromatase inhibitors in ameliorating deleterious effects of ovarian stimulation on outcome of infertility treatment

    PubMed Central

    Mitwally, Mohamed FM; Casper, Robert F; Diamond, Michael P

    2005-01-01

    Clinical utilization of ovulation stimulation to facilitate the ability of a couple to conceive has not only provided a valuable therapeutic approach, but has also yielded extensive information on the physiology of ovarian follicular recruitment, endometrial receptivity and early embryo competency. One of the consequences of the use of fertility enhancing agents for ovarian stimulation has been the creation of a hyperestrogenic state, which may influence each of these parameters. Use of aromatase inhibitors reduces hyperestrogenism inevitably attained during ovarian stimulation. In addition, the adjunct use of aromatase inhibitors during ovarian stimulation reduces amount of gonadotropins required for optimum stimulation. The unique approach of reducing hyperestrogenism, as well as lowering amount of gonadotropins without affecting the number of mature ovarian follicles is an exciting strategy that could result in improvement in the treatment outcome by ameliorating the deleterious effects of the ovarian stimulation on follicular development, endometrial receptivity, as well as oocyte and embryo quality. PMID:16202169

  16. WS-SNPs&GO: a web server for predicting the deleterious effect of human protein variants using functional annotation

    PubMed Central

    2013-01-01

    Background SNPs&GO is a method for the prediction of deleterious Single Amino acid Polymorphisms (SAPs) using protein functional annotation. In this work, we present the web server implementation of SNPs&GO (WS-SNPs&GO). The server is based on Support Vector Machines (SVM) and for a given protein, its input comprises: the sequence and/or its three-dimensional structure (when available), a set of target variations and its functional Gene Ontology (GO) terms. The output of the server provides, for each protein variation, the probabilities to be associated to human diseases. Results The server consists of two main components, including updated versions of the sequence-based SNPs&GO (recently scored as one of the best algorithms for predicting deleterious SAPs) and of the structure-based SNPs&GO3d programs. Sequence and structure based algorithms are extensively tested on a large set of annotated variations extracted from the SwissVar database. Selecting a balanced dataset with more than 38,000 SAPs, the sequence-based approach achieves 81% overall accuracy, 0.61 correlation coefficient and an Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve of 0.88. For the subset of ~6,600 variations mapped on protein structures available at the Protein Data Bank (PDB), the structure-based method scores with 84% overall accuracy, 0.68 correlation coefficient, and 0.91 AUC. When tested on a new blind set of variations, the results of the server are 79% and 83% overall accuracy for the sequence-based and structure-based inputs, respectively. Conclusions WS-SNPs&GO is a valuable tool that includes in a unique framework information derived from protein sequence, structure, evolutionary profile, and protein function. WS-SNPs&GO is freely available at http://snps.biofold.org/snps-and-go. PMID:23819482

  17. Comparison of the deleterious effects of binge drinking-like alcohol exposure in adolescent and adult mice.

    PubMed

    Lacaille, Hélène; Duterte-Boucher, Dominique; Liot, Donovan; Vaudry, Hubert; Naassila, Mickael; Vaudry, David

    2015-03-01

    A major cause of alcohol toxicity is the production of reactive oxygen species generated during ethanol metabolism. The aim of this study was to compare the effect of binge drinking-like alcohol exposure on a panel of genes implicated in oxidative mechanisms in adolescent and adult mice. In adolescent animals, alcohol decreased the expression of genes involved in the repair and protection of oxidative DNA damage such as atr, gpx7, or nudt15 and increased the expression of proapoptotic genes such as casp3. In contrast, in the adult brain, genes activated by alcohol were mainly associated with protective mechanisms that prevent cells from oxidative damage. Whatever the age, iterative binge-like episodes provoked the same deleterious effects as those observed after a single binge episode. In adolescent mice, multiple binge ethanol exposure substantially reduced neurogenesis in the dentate gyrus and impaired short-term memory in the novel object and passive avoidance tests. Taken together, our results indicate that alcohol causes deleterious effects in the adolescent brain which are distinct from those observed in adults. These data contribute to explain the greater sensitivity of the adolescent brain to alcohol toxicity. The effects of alcohol exposure were investigated on genes involved in oxidative mechanisms. In adolescent animals, alcohol decreased the expression of genes involved in DNA repair, a potential cause of the observed decrease of neurogenesis. In contrast, in the adult brain, alcohol increased the expression of genes associated with antioxidant mechanisms. Apoptosis was increase in all groups and converged with other biochemical alterations to enhance short-term memory impairment in the adolescent brain. These data contribute to explain the greater sensitivity of the adolescent brain to alcohol toxicity.

  18. The Founder Strains of the Collaborative Cross Express a Complex Combination of Advantageous and Deleterious Traits for Male Reproduction

    PubMed Central

    Odet, Fanny; Pan, Wenqi; Bell, Timothy A.; Goodson, Summer G.; Stevans, Alicia M.; Yun, Zianing; Aylor, David L.; Kao, Chia-Yu; McMillan, Leonard; de Villena, Fernando Pardo-Manuel; O’Brien, Deborah A.

    2015-01-01

    Surveys of inbred strains of mice are standard approaches to determine the heritability and range of phenotypic variation for biomedical traits. In addition, they may lead to the identification of novel phenotypes and models of human disease. Surprisingly, male reproductive phenotypes are among the least-represented traits in the Mouse Phenome Database. Here we report the results of a broad survey of the eight founder inbred strains of both the Collaborative Cross (CC) and the Diversity Outbred populations, two new mouse resources that are being used as platforms for systems genetics and sources of mouse models of human diseases. Our survey includes representatives of the three main subspecies of the house mice and a mix of classical and wild-derived inbred strains. In addition to standard staples of male reproductive phenotyping such as reproductive organ weights, sperm counts, and sperm morphology, our survey includes sperm motility and the first detailed survey of testis histology. As expected for such a broad survey, heritability varies widely among traits. We conclude that although all eight inbred strains are fertile, most display a mix of advantageous and deleterious male reproductive traits. The CAST/EiJ strain is an outlier, with an unusual combination of deleterious male reproductive traits including low sperm counts, high levels of morphologically abnormal sperm, and poor motility. In contrast, sperm from the PWK/PhJ and WSB/EiJ strains had the greatest percentages of normal morphology and vigorous motility. Finally, we report an abnormal testis phenotype that is highly heritable and restricted to the WSB/EiJ strain. This phenotype is characterized by the presence of a large, but variable, number of vacuoles in at least 10% of the seminiferous tubules. The onset of the phenotype between 2 and 3 wk of age is temporally correlated with the formation of the blood-testis barrier. We speculate that this phenotype may play a role in high rates of extinction in

  19. L-Cysteine ethyl ester reverses the deleterious effects of morphine on, arterial blood-gas chemistry in tracheotomized rats.

    PubMed

    Mendoza, James; Passafaro, Rachael; Baby, Santhosh; Young, Alex P; Bates, James N; Gaston, Benjamin; Lewis, Stephen J

    2013-10-01

    This study determined whether the membrane-permeable ventilatory stimulant, L-cysteine ethylester (L-CYSee), reversed the deleterious actions of morphine on arterial blood-gas chemistry in isoflurane-anesthetized rats. Morphine (2 mg/kg, i.v.) elicited sustained decreases in arterial blood pH, pO₂ and sO₂, and increases in pCO₂ (all responses indicative of hypoventilation) and alveolar-arterial gradient (indicative of ventilation-perfusion mismatch). Injections of L-CYSee (100 μmol/kg, i.v.) reversed the effects of morphine in tracheotomized rats but were minimally active in non-tracheotomized rats. L-cysteine or L-serine ethylester (100 μmol/kg, i.v.) were without effect. It is evident that L-CYSee can reverse the negative effects of morphine on arterial blood-gas chemistry and alveolar-arterial gradient but that this positive activity is negated by increases in upper-airway resistance. Since L-cysteine and L-serine ethylester were ineffective, it is evident that cell penetrability and the sulfur moiety of L-CYSee are essential for activity. Due to its ready penetrability into the lungs, chest wall muscle and brain, the effects of L-CYSee on morphine-induced changes in arterial blood-gas chemistry are likely to involve both central and peripheral sites of action.

  20. Interlocus gene conversion events introduce deleterious mutations into at least 1% of human genes associated with inherited disease.

    PubMed

    Casola, Claudio; Zekonyte, Ugne; Phillips, Andrew D; Cooper, David N; Hahn, Matthew W

    2012-03-01

    Establishing the molecular basis of DNA mutations that cause inherited disease is of fundamental importance to understanding the origin, nature, and clinical sequelae of genetic disorders in humans. The majority of disease-associated mutations constitute single-base substitutions and short deletions and/or insertions resulting from DNA replication errors and the repair of damaged bases. However, pathological mutations can also be introduced by nonreciprocal recombination events between paralogous sequences, a phenomenon known as interlocus gene conversion (IGC). IGC events have thus far been linked to pathology in more than 20 human genes. However, the large number of duplicated gene sequences in the human genome implies that many more disease-associated mutations could originate via IGC. Here, we have used a genome-wide computational approach to identify disease-associated mutations derived from IGC events. Our approach revealed hundreds of known pathological mutations that could have been caused by IGC. Further, we identified several dozen high-confidence cases of inherited disease mutations resulting from IGC in ∼1% of all genes analyzed. About half of the donor sequences associated with such mutations are functional paralogous genes, suggesting that epistatic interactions or differential expression patterns will determine the impact upon fitness of specific substitutions between duplicated genes. In addition, we identified thousands of hitherto undescribed and potentially deleterious mutations that could arise via IGC. Our findings reveal the extent of the impact of interlocus gene conversion upon the spectrum of human inherited disease.

  1. Activators of the Glutamate-Dependent Acid Resistance System Alleviate Deleterious Effects of YidC Depletion in Escherichia coli▿

    PubMed Central

    Yu, Zhong; Bekker, Martijn; Tramonti, Angela; Cook, Gregory M.; van Ulsen, Peter; Scheffers, Dirk-Jan; de Mattos, Joost Teixeira; De Biase, Daniela; Luirink, Joen

    2011-01-01

    The function of the essential inner membrane protein (IMP) YidC in Escherichia coli has been studied for a limited number of model IMPs and primarily using targeted approaches. These studies suggested that YidC acts at the level of insertion, folding, and quality control of IMPs, both in the context of the Sec translocon and as a separate entity. To further our understanding of YidC's role in IMP biogenesis, we screened a random overexpression library for factors that rescued the growth of cells upon YidC depletion. We found that the overexpression of the GadX and GadY regulators of the glutamate-dependent acid resistance system complemented the growth defect of YidC-depleted cells. Evidence is presented that GadXY overexpression counteracts the deleterious effects of YidC depletion on at least two fronts. First, GadXY prepares the cells for the decrease in respiratory capacity upon the depletion of YidC. Most likely, GadXY-regulated processes reduce the drop in proton-motive force that impairs the fitness of YidC-depleted cells. Second, in GadXY-overproducing cells increased levels of the general chaperone GroEL cofractionate with the inner membranes, which may help to keep newly synthesized inner membrane proteins in an insertion-competent state when YidC levels are limiting. PMID:21216990

  2. Imipramine protects against the deleterious effects of chronic corticosterone on depression-like behavior, hippocampal reelin expression, and neuronal maturation.

    PubMed

    Fenton, Erin Y; Fournier, Neil M; Lussier, April L; Romay-Tallon, Raquel; Caruncho, Hector J; Kalynchuk, Lisa E

    2015-07-03

    We have hypothesized that a downregulation of reelin and deficient maturation of adult-born hippocampal neurons are important factors in the pathogenesis of depression. This hypothesis is based on previous work showing that depression-like behavior in rats treated with protracted corticosterone develops in concert with decreased dendritic complexity in newborn hippocampal granule neurons and decreased reelin expression in the proliferative subgranular zone of the dentate gyrus. In addition, heterozygous reeler mice with approximately 50% of normal brain levels of reelin are more vulnerable to the depressogenic effects of corticosterone than wild-type mice. The purpose of this experiment was to provide pharmacological validation for the link between reelin, neuronal maturation, and depression by examining whether the deleterious effects of corticosterone on these measures could be prevented by co-administration of the antidepressant imipramine. Rats received corticosterone injections, corticosterone injections plus either 10 or 15mg/kg imipramine injections, or vehicle injections for 21 consecutive days. They were then subjected to the forced swim test to assess depression-like behavior and sacrificed for immunohistochemical examination of immature neuron number and dendritic complexity and the presence of reelin+cells. We found that corticosterone increases depression-like behavior, decreases the number of reelin+cells in the subgranular zone, and decreases the number and complexity of immature neurons in the granule cell layer. All of these behavioral and cellular phenotypes were prevented by imipramine, providing further support for the idea that reelin is involved in the pathogenesis of depression.

  3. Identification of Deleterious Mutations in Myostatin Gene of Rohu Carp (Labeo rohita) Using Modeling and Molecular Dynamic Simulation Approaches.

    PubMed

    Rasal, Kiran Dashrath; Chakrapani, Vemulawada; Patra, Swagat Kumar; Mohapatra, Shibani D; Nayak, Swapnarani; Jena, Sasmita; Sundaray, Jitendra Kumar; Jayasankar, Pallipuram; Barman, Hirak Kumar

    2016-01-01

    The myostatin (MSTN) is a known negative growth regulator of skeletal muscle. The mutated myostatin showed a double-muscular phenotype having a positive significance for the farmed animals. Consequently, adequate information is not available in the teleosts, including farmed rohu carp, Labeo rohita. In the absence of experimental evidence, computational algorithms were utilized in predicting the impact of point mutation of rohu myostatin, especially its structural and functional relationships. The four mutations were generated at different positions (p.D76A, p.Q204P, p.C312Y, and p.D313A) of MSTN protein of rohu. The impacts of each mutant were analyzed using SIFT, I-Mutant 2.0, PANTHER, and PROVEAN, wherein two substitutions (p.D76A and p.Q204P) were predicted as deleterious. The comparative structural analysis of each mutant protein with the native was explored using 3D modeling as well as molecular-dynamic simulation techniques. The simulation showed altered dynamic behaviors concerning RMSD and RMSF, for either p.D76A or p.Q204P substitution, when compared with the native counterpart. Interestingly, incorporated two mutations imposed a significant negative impact on protein structure and stability. The present study provided the first-hand information in identifying possible amino acids, where mutations could be incorporated into MSTN gene of rohu carp including other carps for undertaking further in vivo studies.

  4. Identification of Deleterious Mutations in Myostatin Gene of Rohu Carp (Labeo rohita) Using Modeling and Molecular Dynamic Simulation Approaches

    PubMed Central

    Rasal, Kiran Dashrath; Chakrapani, Vemulawada; Patra, Swagat Kumar; Mohapatra, Shibani D.; Nayak, Swapnarani; Jena, Sasmita; Sundaray, Jitendra Kumar; Jayasankar, Pallipuram; Barman, Hirak Kumar

    2016-01-01

    The myostatin (MSTN) is a known negative growth regulator of skeletal muscle. The mutated myostatin showed a double-muscular phenotype having a positive significance for the farmed animals. Consequently, adequate information is not available in the teleosts, including farmed rohu carp, Labeo rohita. In the absence of experimental evidence, computational algorithms were utilized in predicting the impact of point mutation of rohu myostatin, especially its structural and functional relationships. The four mutations were generated at different positions (p.D76A, p.Q204P, p.C312Y, and p.D313A) of MSTN protein of rohu. The impacts of each mutant were analyzed using SIFT, I-Mutant 2.0, PANTHER, and PROVEAN, wherein two substitutions (p.D76A and p.Q204P) were predicted as deleterious. The comparative structural analysis of each mutant protein with the native was explored using 3D modeling as well as molecular-dynamic simulation techniques. The simulation showed altered dynamic behaviors concerning RMSD and RMSF, for either p.D76A or p.Q204P substitution, when compared with the native counterpart. Interestingly, incorporated two mutations imposed a significant negative impact on protein structure and stability. The present study provided the first-hand information in identifying possible amino acids, where mutations could be incorporated into MSTN gene of rohu carp including other carps for undertaking further in vivo studies. PMID:27019850

  5. Tanshinol Attenuates the Deleterious Effects of Oxidative Stress on Osteoblastic Differentiation via Wnt/FoxO3a Signaling

    PubMed Central

    Yang, Yajun; Su, Yanjie; Wang, Dongtao; Chen, Yahui; Wu, Tie; Li, Gang; Sun, Xuegang

    2013-01-01

    There is now increasing evidence which suggests a pivotal role for oxidative stress in the development and progression of osteoporosis. We confirm herein the protective effects of natural antioxidant Tanshinol against oxidative stress in osteoblastic differentiation and the underlying mechanism. Our results show that hydrogen peroxide (H2O2) leads to accumulation of reactive oxygen species (ROS), decrease in cell viability, cell cycle arrest and apoptosis in a caspase-3-dependent manner, and inhibition of osteoblastic differentiation. Tanshinol reverses these deleterious consequence triggered by oxidative stress. Moreover, under the condition of oxidative stress, Tanshinol suppresses the activation of FoxO3a transcription factor and expressions of its target genes Gadd45a and catalase (CAT) and simultaneously counteracts the inhibition of Wnt signalling and expressions of target genes Axin2, alkaline phosphatase (ALP), and Osteoprotegerin (OPG). The findings are further consolidated using FoxO3a siRNA interference and overexpression of Tcf4. The results illustrate that Tanshinol attenuates oxidative stress via down-regulation of FoxO3a signaling, and rescues the decrease of osteoblastic differentiation through upregulation of Wnt signal under oxidative stress. The present findings suggest that the beneficial effects of Tanshinol may be adopted as a novel therapeutic approach in recently recognized conditions of niche targeting osteoporosis. PMID:24489983

  6. Enhanced fixation and preservation of a newly arisen duplicate gene by masking deleterious loss-of-function mutations.

    PubMed

    Tanaka, Kentaro M; Takahasi, K Ryo; Takano-Shimizu, Toshiyuki

    2009-08-01

    Segmental duplications are enriched within many eukaryote genomes, and their potential consequence is gene duplication. While previous theoretical studies of gene duplication have mainly focused on the gene silencing process after fixation, the process leading to fixation is even more important for segmental duplications, because the majority of duplications would be lost before reaching a significant frequency in a population. Here, by a series of computer simulations, we show that purifying selection against loss-of-function mutations increases the fixation probability of a new duplicate gene, especially when the gene is haplo-insufficient. Theoretically, the probability of simultaneous preservation of both duplicate genes becomes twice the loss-of-function mutation rate (u(c)) when the population size (N), the degree of dominance of mutations (h) and the recombination rate between the duplicate genes (c) are all sufficiently large (Nu(c)>1, h>0.1 and c>u(c)). The preservation probability declines rapidly with h and becomes 0 when h=0 (haplo-sufficiency). We infer that masking deleterious loss-of-function mutations give duplicate genes an immediate selective advantage and, together with effects of increased gene dosage, would predominantly determine the fates of the duplicate genes in the early phase of their evolution.

  7. Deleterious coding variants in multi-case families with non-syndromic cleft lip and/or palate phenotypes

    PubMed Central

    Pengelly, Reuben J.; Arias, Liliana; Martínez, Julio; Upstill-Goddard, Rosanna; Seaby, Eleanor G.; Gibson, Jane; Ennis, Sarah; Collins, Andrew; Briceño, Ignacio

    2016-01-01

    Nonsyndromic Cleft Lip and/or Palate (NSCLP) is regarded as a multifactorial condition in which clefting is an isolated phenotype, distinguished from the largely monogenic, syndromic forms which include clefts among a spectrum of phenotypes. Nonsyndromic clefting has been shown to arise through complex interactions between genetic and environmental factors. However, there is increasing evidence that the broad NSCLP classification may include a proportion of cases showing familial patterns of inheritance and contain highly penetrant deleterious variation in specific genes. Through exome sequencing of multi-case families ascertained in Bogota, Colombia, we identify 28 non-synonymous single nucleotide variants that are considered damaging by at least one predictive score. We discuss the functional impact of candidate variants identified. In one family we find a coding variant in the MSX1 gene which is predicted damaging by multiple scores. This variant is in exon 2, a highly conserved region of the gene. Previous sequencing has suggested that mutations in MSX1 may account for ~2% of NSCLP. Our analysis further supports evidence that a proportion of NSCLP cases arise through monogenic coding mutations, though further work is required to unravel the complex interplay of genetics and environment involved in facial clefting. PMID:27456059

  8. Deleterious effects of sunscreen titanium dioxide nanoparticles on DNA: efforts to limit DNA damage by particle surface modification

    NASA Astrophysics Data System (ADS)

    Serpone, Nick; Salinaro, Angela; Emeline, A.

    2001-06-01

    Sunlight can have deleterious effects on humans: causes sunburns and is the principal cause of skin cancers. Usage of TiO2 (and ZnO) in sunscreen lotions, widely used as UVA/UVB blockers, and intended to prevent sunburns and to protect consumers from skin cancers (carcinomas and melanomas) is examined. Although used to mineralize many undesired organic pollutants, TiO2 is considered to be a safe physical sunscreen agent because it reflects and scatters both UVB (290-320 nm) and UVA (320-400 nm) sunlight; however, it also absorbs substantial UV radiation which, in aqueous media, yields hydroxyl radial ((DOT)OH) species. These species cause substantial damage to DNA (J. Photochem.Photobio.A:Chem.,111(1997)205). Most importantly, sunlight-illuminated sunscreen TiO2 particles catalyze DNA damage both in vitro and in human cells (FEBS Letters, 418 (1997)87). These results raise concerns on the overall effects of sunscreens and raise the question on the suitability of photoactive TiO2 as a sunscreen component without further studies. The photocatalytically active nature of these metal oxides necessitates some changes since even the TiO2 specimens currently used in suncreams cause significant DNA strand breaks.

  9. De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features

    PubMed Central

    Webster, Emily; Cho, Megan T.; Alexander, Nora; Desai, Sonal; Naidu, Sakkubai; Bekheirnia, Mir Reza; Lewis, Andrea; Retterer, Kyle; Juusola, Jane; Chung, Wendy K.

    2016-01-01

    Using whole-exome sequencing, we have identified novel de novo heterozygous pleckstrin homology domain-interacting protein (PHIP) variants that are predicted to be deleterious, including a frameshift deletion, in two unrelated patients with common clinical features of developmental delay, intellectual disability, anxiety, hypotonia, poor balance, obesity, and dysmorphic features. A nonsense mutation in PHIP has previously been associated with similar clinical features. Patients with microdeletions of 6q14.1, including PHIP, have a similar phenotype of developmental delay, intellectual disability, hypotonia, and obesity, suggesting that the phenotype of our patients is a result of loss-of-function mutations. PHIP produces multiple protein products, such as PHIP1 (also known as DCAF14), PHIP, and NDRP. PHIP1 is one of the multiple substrate receptors of the proteolytic CUL4-DDB1 ubiquitin ligase complex. CUL4B deficiency has been associated with intellectual disability, central obesity, muscle wasting, and dysmorphic features. The overlapping phenotype associated with CUL4B deficiency suggests that PHIP mutations cause disease through disruption of the ubiquitin ligase pathway. PMID:27900362

  10. The effects of a deleterious mutation load on patterns of influenza A/H3N2's antigenic evolution in humans

    PubMed Central

    Koelle, Katia; Rasmussen, David A

    2015-01-01

    Recent phylogenetic analyses indicate that RNA virus populations carry a significant deleterious mutation load. This mutation load has the potential to shape patterns of adaptive evolution via genetic linkage to beneficial mutations. Here, we examine the effect of deleterious mutations on patterns of influenza A subtype H3N2's antigenic evolution in humans. By first analyzing simple models of influenza that incorporate a mutation load, we show that deleterious mutations, as expected, act to slow the virus's rate of antigenic evolution, while making it more punctuated in nature. These models further predict three distinct molecular pathways by which antigenic cluster transitions occur, and we find phylogenetic patterns consistent with each of these pathways in influenza virus sequences. Simulations of a more complex phylodynamic model further indicate that antigenic mutations act in concert with deleterious mutations to reproduce influenza's spindly hemagglutinin phylogeny, co-circulation of antigenic variants, and high annual attack rates. DOI: http://dx.doi.org/10.7554/eLife.07361.001 PMID:26371556

  11. Positive Selection of Deleterious Alleles through Interaction with a Sex-Ratio Suppressor Gene in African Buffalo: A Plausible New Mechanism for a High Frequency Anomaly

    PubMed Central

    van Hooft, Pim; Greyling, Ben J.; Getz, Wayne M.; van Helden, Paul D.; Zwaan, Bas J.; Bastos, Armanda D. S.

    2014-01-01

    Although generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer) population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this body-condition-associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations), we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has important

  12. Harnessing Mechanistic Knowledge on Beneficial Versus Deleterious IFN-I Effects to Design Innovative Immunotherapies Targeting Cytokine Activity to Specific Cell Types

    PubMed Central

    Tomasello, Elena; Pollet, Emeline; Vu Manh, Thien-Phong; Uzé, Gilles; Dalod, Marc

    2014-01-01

    Type I interferons (IFN-I) were identified over 50 years ago as cytokines critical for host defense against viral infections. IFN-I promote anti-viral defense through two main mechanisms. First, IFN-I directly reinforce or induce de novo in potentially all cells the expression of effector molecules of intrinsic anti-viral immunity. Second, IFN-I orchestrate innate and adaptive anti-viral immunity. However, IFN-I responses can be deleterious for the host in a number of circumstances, including secondary bacterial or fungal infections, several autoimmune diseases, and, paradoxically, certain chronic viral infections. We will review the proposed nature of protective versus deleterious IFN-I responses in selected diseases. Emphasis will be put on the potentially deleterious functions of IFN-I in human immunodeficiency virus type 1 (HIV-1) infection, and on the respective roles of IFN-I and IFN-III in promoting resolution of hepatitis C virus (HCV) infection. We will then discuss how the balance between beneficial versus deleterious IFN-I responses is modulated by several key parameters including (i) the subtypes and dose of IFN-I produced, (ii) the cell types affected by IFN-I, and (iii) the source and timing of IFN-I production. Finally, we will speculate how integration of this knowledge combined with advanced biochemical manipulation of the activity of the cytokines should allow designing innovative immunotherapeutic treatments in patients. Specifically, we will discuss how induction or blockade of specific IFN-I responses in targeted cell types could promote the beneficial functions of IFN-I and/or dampen their deleterious effects, in a manner adapted to each disease. PMID:25400632

  13. Positive selection of deleterious alleles through interaction with a sex-ratio suppressor gene in African Buffalo: a plausible new mechanism for a high frequency anomaly.

    PubMed

    van Hooft, Pim; Greyling, Ben J; Getz, Wayne M; van Helden, Paul D; Zwaan, Bas J; Bastos, Armanda D S

    2014-01-01

    Although generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer) population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this body-condition-associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations), we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has important

  14. Quality of the Exotic Parasitoid Cotesia flavipes (Hymenoptera: Braconidae) Does Not Show Deleterious Effects after Inbreeding for 10 Generations

    PubMed Central

    Trevisan, Maíra; De Bortoli, Sergio A.; Vacari, Alessandra M.; Laurentis, Valéria L.; Ramalho, Dagmara G.

    2016-01-01

    Although the parasitoid Cotesia flavipes (Cameron) has proven effective in controlling sugarcane borer Diatraea saccharalis (Fabricius) for many years, concern has arisen over the quality of individuals produced at large scales. The parasitoid has been reared in laboratories in Brazil for more than 40 years, with no new introductions of new populations during that period. Since the quality of the parasitoids was not verified at the time of the species' introduction in Brazil, we do not know if there has been any reduction in quality so far. However, it is possible to determine whether the parasitoid could reduce in quality in future generations. Thus, the objective of this research was to assess the quality of these insects over 10 generations and look for evidence of any loss in quality. We used two populations: one from a biofactory that has been maintained in the laboratory for over 40 years, and an inbred laboratory population. Both were bred, and compared for 10 generations. We wanted to determine what happened to the quality of the parasitoid after 10 generations in an extreme inbreeding situation. To assure inbreeding, newly emerged females were forced to mate with a sibling. Individual females were then allowed to parasitize larvae of D. saccharalis. We performed evaluations for each generation until the tenth generation, and recorded the sex ratio, percentage emergence, number of offspring/females, and longevity of both males and females. Results of the measurements of biological characteristics demonstrated random significant differences between populations; best results were obtained intermittently for both the biofactory population and the inbred population. No significant differences across generations for the same population were observed. Thus, rearing of a C. flavipes population subjected to inbreeding for 10 generations was not sufficient to reveal any deleterious effects of inbreeding. PMID:27509087

  15. An Excess of Deleterious Variants in VEGF-A Pathway Genes in Down-Syndrome-Associated Atrioventricular Septal Defects

    PubMed Central

    Ackerman, Christine; Locke, Adam E.; Feingold, Eleanor; Reshey, Benjamin; Espana, Karina; Thusberg, Janita; Mooney, Sean; Bean, Lora J.H.; Dooley, Kenneth J.; Cua, Clifford L.; Reeves, Roger H.; Sherman, Stephanie L.; Maslen, Cheryl L.

    2012-01-01

    About half of people with trisomy 21 have a congenital heart defect (CHD), whereas the remainder have a structurally normal heart, demonstrating that trisomy 21 is a significant risk factor but is not causal for abnormal heart development. Atrioventricular septal defects (AVSD) are the most commonly occurring heart defects in Down syndrome (DS), and ∼65% of all AVSD is associated with DS. We used a candidate-gene approach among individuals with DS and complete AVSD (cases = 141) and DS with no CHD (controls = 141) to determine whether rare genetic variants in genes involved in atrioventricular valvuloseptal morphogenesis contribute to AVSD in this sensitized population. We found a significant excess (p < 0.0001) of variants predicted to be deleterious in cases compared to controls. At the most stringent level of filtering, we found potentially damaging variants in nearly 20% of cases but fewer than 3% of controls. The variants with the highest probability of being damaging in cases only were found in six genes: COL6A1, COL6A2, CRELD1, FBLN2, FRZB, and GATA5. Several of the case-specific variants were recurrent in unrelated individuals, occurring in 10% of cases studied. No variants with an equal probability of being damaging were found in controls, demonstrating a highly specific association with AVSD. Of note, all of these genes are in the VEGF-A pathway, even though the candidate genes analyzed in this study represented numerous biochemical and developmental pathways, suggesting that rare variants in the VEGF-A pathway might contribute to the genetic underpinnings of AVSD in humans. PMID:23040494

  16. Analysis of the biases in the estimation of deleterious mutation parameters from natural populations at mutation-selection balance.

    PubMed

    Caballero, A

    2006-12-01

    Indirect estimates of the genomic rate of deleterious mutations (lambda), their average homozygous effect (s) and their degree of dominance (h) can be obtained from genetic parameters of natural populations, assuming that the frequencies of the loci controlling a given fitness trait are at mutation-selection equilibrium. In 1996, H.-W. Deng and M. Lynch developed a general methodology for obtaining these estimates from inbreeding/outbreeding experiments. The prediction of the sign and magnitude of the biases incurred by these estimators is essential for a correct interpretation of the empirical results. However, the assessment of these biases has been tested so far under a rather limited model of the distribution of dominance effects. In this paper, the application of this method to outbred populations is evaluated, focusing on the level of variation in h values (sigma(h)(2) and the magnitude of the negative correlation (rs,h) between s and h. It is shown that the method produces upwardly biased estimates of lambda and downwardly biased estimates of the average s in the reference situation where rs,h=0, particularly for large values of sigma(h)(2), and biases of different sign depending on the magnitude of the correlation. A modification of the method, substituting the estimates of the average h for alternative ones, allows estimates to be obtained with little or no bias for the case of rs,h=0, but is otherwise biased. Information on rs,h and sigma(h)(2), gathered from mutation-accumulation experiments, suggests that sigma(h)(2) may be rather large and rs,h is usually negative but not higher than about -0.2, although the data are scarce and noisy, and should be used with caution.

  17. Frequent germline deleterious mutations in DNA repair genes in familial prostate cancer cases are associated with advanced disease

    PubMed Central

    Leongamornlert, D; Saunders, E; Dadaev, T; Tymrakiewicz, M; Goh, C; Jugurnauth-Little, S; Kozarewa, I; Fenwick, K; Assiotis, I; Barrowdale, D; Govindasami, K; Guy, M; Sawyer, E; Wilkinson, R; Antoniou, A C; Eeles, R; Kote-Jarai, Z

    2014-01-01

    Background: Prostate cancer (PrCa) is one of the most common diseases to affect men worldwide and among the leading causes of cancer-related death. The purpose of this study was to use second-generation sequencing technology to assess the frequency of deleterious mutations in 22 tumour suppressor genes in familial PrCa and estimate the relative risk of PrCa if these genes are mutated. Methods: Germline DNA samples from 191 men with 3 or more cases of PrCa in their family were sequenced for 22 tumour suppressor genes using Agilent target enrichment and Illumina technology. Analysis for genetic variation was carried out by using a pipeline consisting of BWA, Genome Analysis Toolkit (GATK) and ANNOVAR. Clinical features were correlated with mutation status using standard statistical tests. Modified segregation analysis was used to determine the relative risk of PrCa conferred by the putative loss-of-function (LoF) mutations identified. Results: We discovered 14 putative LoF mutations in 191 samples (7.3%) and these mutations were more frequently associated with nodal involvement, metastasis or T4 tumour stage (P=0.00164). Segregation analysis of probands with European ancestry estimated that LoF mutations in any of the studied genes confer a relative risk of PrCa of 1.94 (95% CI: 1.56–2.42). Conclusions: These findings show that LoF mutations in DNA repair pathway genes predispose to familial PrCa and advanced disease and therefore warrants further investigation. The clinical utility of these findings will become increasingly important as targeted screening and therapies become more widespread. PMID:24556621

  18. A novel approach to the pulmonary delivery of liposomes in dry powder form to eliminate the deleterious effects of milling.

    PubMed

    Desai, Tejas R; Wong, Jonathan P; Hancock, Robert E W; Finlay, Warren H

    2002-02-01

    The effect of lyophilization and jet-milling on liposome integrity was investigated as a function of their ability to retain the encapsulated model drug on reconstitution of the dry products. The encapsulation efficiencies of the lyophilized and jet-milled formulations were determined at various concentrations of lactose. Lyophilization resulted in considerable leakage of the model drug at lower concentrations of lactose, and jet-milling further augmented the leakage for all the lyophilized formulations, with optimum retention obtained for formulations containing at least 10:1 molar ratio of lactose/lipid. In an attempt to overcome the deleterious effects of lyophilization and jet-milling, the feasibility of formulating phospholipid-based powders that result in spontaneous formation of liposomes in an aqueous environment has been investigated. Partitioning of three model drugs (viz., ciprofloxacin, CM3 peptide, and salbutamol sulfate) between the aqueous phase and spontaneously formed liposomes was determined in terms of encapsulation efficiency. The effects of several parameters, including lactose concentration, lipid composition, and lipid concentration on the encapsulation efficiency of these model drugs were investigated. The spontaneous formation of liposomes on dispersion of phospholipid-based powder formulations was further evidenced by freeze-fracture scanning electron microscopy. This novel approach for the delivery of liposomes in dry powder form appears promising because lyophilization is not involved and jet-milling of these powder formulations did not impact encapsulation efficiency. Jet-milled phospholipid-based powder formulations showed high encapsulation efficiencies of 96.2 +/- 1.4% for ciprofloxacin, 100% for CM3 peptide, and 45.3 +/- 3.1% for salbutamol sulfate compared with a high amount of leakage (> 50%) observed due to jet-milling of lyophilized liposome formulations encapsulating ciprofloxacin.

  19. Deleterious effects of glucocorticoid replacement on bone in women after long-term remission of Cushing's syndrome.

    PubMed

    Barahona, Maria-José; Sucunza, Nuria; Resmini, Eugenia; Fernández-Real, Jose-Manuel; Ricart, Wifredo; Moreno-Navarrete, Jose-Maria; Puig, Teresa; Wägner, Ana M; Rodriguez-Espinosa, José; Farrerons, Jordi; Webb, Susan M

    2009-11-01

    Endogenous hypercortisolism and high-dose and long-term glucocorticoid (GC) therapy reduce bone mass. Patients in remission after successful treatment of Cushing's syndrome (CS) often present hypoadrenalism and require long-term GC replacement. The aim of our study was to evaluate whether this GC "replacement" had any further effect on bone in women after long-term remission of CS. Thirty-seven women (mean age: 50 +/- 14 yr; 27 of pituitary and 10 of adrenal origin) with cured CS (mean time of cure: 11 +/- 6 yr), 14 with active CS, and 85 sex-, body mass index (BMI)-, and age-matched controls were enrolled. BMD and BMC were measured by DXA scanning. Bone biochemical markers were also measured. Duration and dose of GC replacement and duration of endogenous hypercortisolism were calculated. Cured and active CS patients had less BMC, BMD, and osteocalcin than controls (p < 0.01). These differences were observed in estrogen-sufficient women but not in those with estrogen deficiency. Duration of GC treatment (mean: 42 mo; range, 2-420 mo) and endogenous hypercortisolism (mean: 70 mo; range, 13-241 mo) negatively correlated with BMC and lumbar spine BMD. After regression analysis, the main predictor of abnormal BMC and BMD was the duration of GC replacement (p < 0.01). Patients treated for CS persistently have less bone mass despite long-term cure. Both duration of endogenous hypercortisolism and mainly exogenous "replacement" therapy with GC negatively affect bone mass. Thus, the additional deleterious effect of GC for the treatment of adrenal axis suppression should be considered.

  20. Deleterious Effects of Minocycline after in vivo Target Deprivation of Thalamocortical Neurons in the Immature, Metallothionein-Deficient Mouse Brain

    PubMed Central

    Potter, Emily G.; Cheng, Ying; Natale, JoAnne E.

    2015-01-01

    Compared to adults, immature metallothionein I & II knockout (MT−/−) mice incur greater neuronal loss and a more rapid rate of microglia accumulation following target deprivation-induced injury. Since minocycline has been proposed to inhibit microglial activation and associated production of neuroinflammatory factors, we investigated its ability to promote neuronal survival in the immature, metallothionein-deficient brain. Following ablation of the visual cortex, 10-day-old MT−/− mice were treated with minocycline or saline and sacrificed 24 or 48 hours after injury. Using stereological methods, the number of microglia and neurons were estimated in the ipsilateral dorsal lateral geniculate nucleus (dLGN) by an investigator blinded to the treatment. No effect on neuronal survival was observed at 24 hours, but 48 hours after injury an unanticipated but significant minocycline-mediated increase in neuronal loss was detected. Further, while failing to inhibit microglial accumulation, minocycline treatment increased the proportion of amoeboid microglia in the ipsilateral dLGN. To understand the molecular mechanisms underlying this neurotoxic response, we identified minocycline-mediated changes in the expression of three potentially pro-apoptotic/ inflammatory genes: growth arrest- and DNA damage-inducible gene 45γ (GADD45γ); interferon-inducible protein 1 (IFI1) and cytokine induced growth factor (CTGF). We also observed increased mitogen-activated protein kinase (MAPK) p38 phosphorylation with minocycline treatment. Although minocycline inhibited calpain activity at 12 hours post-injury, this effect was not sustained at 24 hours. Together, these results help to explain how minocycline has a deleterious effect on neuronal survival in this injury model. PMID:19115404

  1. Long-term excessive magnesium supplementation is deleterious whereas suboptimal supply is beneficial for bones in rats.

    PubMed

    Riond, J L; Hartmann, P; Steiner, P; Ursprung, R; Wanner, M; Forrer, R; Spichiger, U E; Thomsen, J S; Mosekilde, L

    2000-12-01

    the parameters indicators of bone health whereas the long-term supplementation was deleterious.

  2. Structures and characteristics of novel siderophores from plant deleterious Pseudomonas fluorescens A225 and Pseudomonas putida ATCC 39167.

    PubMed

    Khalil-Rizvi, S; Toth, S I; van der Helm, D; Vidavsky, I; Gross, M L

    1997-04-08

    When Pseudomonas putida ATCC 39167 and plant-deleterious Pseudomonas fluorescens A225 were grown in an iron-deficient culture medium, they each produced two different novel yellow-green fluorescent pseudobactins: P39167-I, II and PA225-I, II. Pseudobactin P39167-I has a molecular formula of C46H65O23N13 and is monoanionic at neutral pH. P39167-II has the molecular formula of C46H63O22N13 and no charge at neutral pH. Pseudobactin PA225-I has a molecular formula of C46H65O24N13 and is monoanionic at neutral pH whereas pseudobactin PA225-II has the molecular formula of C46H63O23N13 and no charge at neutral pH. All four of the pseudobactins contain a dihydroxyquinoline-based chromophore. The amino acid sequence for the octapeptide in case of pseudobactins from P. putida ATCC 39167 is Chr-Ser(1)-Ala(1)-AcOHOrn-Gly-Ala(2)-OHAsp-Ser(2)-Thr. In case of pseudobactins from P. fluorescens A225, the octapeptide has the sequence Chr-Ser(1)-Ala-AcOHOrn-Gly-Ser(2)-OHAsp-Ser(3)-Thr. For all four pseudobactins (P39167-I, II and PA225-I, II), the serine(1) residue of the octapeptide is attached to the carboxylic acid group on the C-11 of the fluorescent quinoline via an amide bond. Additionally, for pseudobactin P39167-II and PA225-II, the hydroxyl group of the serine(1) residue is also attached to the carboxyl group of threonine residue at the carboxy terminus of the peptide via an ester bond, resulting in a cyclic depsipeptide in contrast to the linear peptide chain of P39167-I and PA225-I. For all four pseudobactins, a malamide group is attached to the C-3 of the quinoline derived chromophore. The three bidentate iron(III) chelating groups in all four pseudobactins consist of a 1,2-dihydroxy aromatic group of the fluorescent chromophore, a hydroxy acid group of beta-hydroxy aspartic acid, and a hydroxamate group from the acylated Ndelta-hydroxyornithine. The amino acid constituents of the pseudobactins P39167 I, II are the same as those in pseudobactin A214, whereas those in A225

  3. Human Spermatogenic Failure Purges Deleterious Mutation Load from the Autosomes and Both Sex Chromosomes, including the Gene DMRT1

    PubMed Central

    Thompson, Emma; Carvalho, Filipa; Gonçalves, João; Huang, Ni; Matthiesen, Rune; Noordam, Michiel J.; Quintela, Inés; Ramu, Avinash; Seabra, Catarina; Wilfert, Amy B.; Dai, Juncheng; Downie, Jonathan M.; Fernandes, Susana; Guo, Xuejiang; Sha, Jiahao; Amorim, António; Barros, Alberto; Carracedo, Angel; Hu, Zhibin; Hurles, Matthew E.; Moskovtsev, Sergey; Ober, Carole; Paduch, Darius A.; Schiffman, Joshua D.; Schlegel, Peter N.; Sousa, Mário; Carrell, Douglas T.; Conrad, Donald F.

    2013-01-01

    Gonadal failure, along with early pregnancy loss and perinatal death, may be an important filter that limits the propagation of harmful mutations in the human population. We hypothesized that men with spermatogenic impairment, a disease with unknown genetic architecture and a common cause of male infertility, are enriched for rare deleterious mutations compared to men with normal spermatogenesis. After assaying genomewide SNPs and CNVs in 323 Caucasian men with idiopathic spermatogenic impairment and more than 1,100 controls, we estimate that each rare autosomal deletion detected in our study multiplicatively changes a man's risk of disease by 10% (OR 1.10 [1.04–1.16], p<2×10−3), rare X-linked CNVs by 29%, (OR 1.29 [1.11–1.50], p<1×10−3), and rare Y-linked duplications by 88% (OR 1.88 [1.13–3.13], p<0.03). By contrasting the properties of our case-specific CNVs with those of CNV callsets from cases of autism, schizophrenia, bipolar disorder, and intellectual disability, we propose that the CNV burden in spermatogenic impairment is distinct from the burden of large, dominant mutations described for neurodevelopmental disorders. We identified two patients with deletions of DMRT1, a gene on chromosome 9p24.3 orthologous to the putative sex determination locus of the avian ZW chromosome system. In an independent sample of Han Chinese men, we identified 3 more DMRT1 deletions in 979 cases of idiopathic azoospermia and none in 1,734 controls, and found none in an additional 4,519 controls from public databases. The combined results indicate that DMRT1 loss-of-function mutations are a risk factor and potential genetic cause of human spermatogenic failure (frequency of 0.38% in 1306 cases and 0% in 7,754 controls, p = 6.2×10−5). Our study identifies other recurrent CNVs as potential causes of idiopathic azoospermia and generates hypotheses for directing future studies on the genetic basis of male infertility and IVF outcomes. PMID:23555275

  4. Human spermatogenic failure purges deleterious mutation load from the autosomes and both sex chromosomes, including the gene DMRT1.

    PubMed

    Lopes, Alexandra M; Aston, Kenneth I; Thompson, Emma; Carvalho, Filipa; Gonçalves, João; Huang, Ni; Matthiesen, Rune; Noordam, Michiel J; Quintela, Inés; Ramu, Avinash; Seabra, Catarina; Wilfert, Amy B; Dai, Juncheng; Downie, Jonathan M; Fernandes, Susana; Guo, Xuejiang; Sha, Jiahao; Amorim, António; Barros, Alberto; Carracedo, Angel; Hu, Zhibin; Hurles, Matthew E; Moskovtsev, Sergey; Ober, Carole; Paduch, Darius A; Schiffman, Joshua D; Schlegel, Peter N; Sousa, Mário; Carrell, Douglas T; Conrad, Donald F

    2013-03-01

    Gonadal failure, along with early pregnancy loss and perinatal death, may be an important filter that limits the propagation of harmful mutations in the human population. We hypothesized that men with spermatogenic impairment, a disease with unknown genetic architecture and a common cause of male infertility, are enriched for rare deleterious mutations compared to men with normal spermatogenesis. After assaying genomewide SNPs and CNVs in 323 Caucasian men with idiopathic spermatogenic impairment and more than 1,100 controls, we estimate that each rare autosomal deletion detected in our study multiplicatively changes a man's risk of disease by 10% (OR 1.10 [1.04-1.16], p<2 × 10(-3)), rare X-linked CNVs by 29%, (OR 1.29 [1.11-1.50], p<1 × 10(-3)), and rare Y-linked duplications by 88% (OR 1.88 [1.13-3.13], p<0.03). By contrasting the properties of our case-specific CNVs with those of CNV callsets from cases of autism, schizophrenia, bipolar disorder, and intellectual disability, we propose that the CNV burden in spermatogenic impairment is distinct from the burden of large, dominant mutations described for neurodevelopmental disorders. We identified two patients with deletions of DMRT1, a gene on chromosome 9p24.3 orthologous to the putative sex determination locus of the avian ZW chromosome system. In an independent sample of Han Chinese men, we identified 3 more DMRT1 deletions in 979 cases of idiopathic azoospermia and none in 1,734 controls, and found none in an additional 4,519 controls from public databases. The combined results indicate that DMRT1 loss-of-function mutations are a risk factor and potential genetic cause of human spermatogenic failure (frequency of 0.38% in 1306 cases and 0% in 7,754 controls, p = 6.2 × 10(-5)). Our study identifies other recurrent CNVs as potential causes of idiopathic azoospermia and generates hypotheses for directing future studies on the genetic basis of male infertility and IVF outcomes.

  5. [Black or white--is amalgam 'out'? Part 1. Amalgam or composite: which of these 2 materials is the most deleterious?].

    PubMed

    De Moor, Roeland; Delmé, Katleen

    2008-01-01

    Dental amalgam containing mercury has been condemned because of its toxicity and hence to be damaging of harmful to the general health. It must be clear that many sensational, confusing and misleading reports have been published. Today there is evidence that dental amalgam in the oral cavity does not harm anyone's health. For those who are condemning amalgam there an abundant number of alarming reports taking into consideration the biologic effects of resin composites: methacrylate allergy for dentists and dental technicians, the three-finger-syndrome due to contact with liquid resin, allergic reactions at the level of the airways and breathing problems caused by dust particles (esp. composite particles after polishing procedures) have been described. It can be concluded that dental amalgam is not more toxic than resin composite in light of both patients' and dental care providers' health. Recent investigations demonstrated higher than expected health risks with resin composites.

  6. Quantifying rare, deleterious variation in 12 human cytochrome P450 drug-metabolism genes in a large-scale exome dataset

    PubMed Central

    Gordon, Adam S.; Tabor, Holly K.; Johnson, Andrew D.; Snively, Beverly M.; Assimes, Themistocles L.; Auer, Paul L.; Ioannidis, John P.A.; Peters, Ulrike; Robinson, Jennifer G.; Sucheston, Lara E.; Wang, Danxin; Sotoodehnia, Nona; Rotter, Jerome I.; Psaty, Bruce M.; Jackson, Rebecca D.; Herrington, David M.; O'Donnell, Christopher J.; Reiner, Alexander P.; Rich, Stephen S.; Rieder, Mark J.; Bamshad, Michael J.; Nickerson, Deborah A.

    2014-01-01

    The study of genetic influences on drug response and efficacy (‘pharmacogenetics’) has existed for over 50 years. Yet, we still lack a complete picture of how genetic variation, both common and rare, affects each individual's responses to medications. Exome sequencing is a promising alternative method for pharmacogenetic discovery as it provides information on both common and rare variation in large numbers of individuals. Using exome data from 2203 AA and 4300 Caucasian individuals through the NHLBI Exome Sequencing Project, we conducted a survey of coding variation within 12 Cytochrome P450 (CYP) genes that are collectively responsible for catalyzing nearly 75% of all known Phase I drug oxidation reactions. In addition to identifying many polymorphisms with known pharmacogenetic effects, we discovered over 730 novel nonsynonymous alleles across the 12 CYP genes of interest. These alleles include many with diverse functional effects such as premature stop codons, aberrant splicesites and mutations at conserved active site residues. Our analysis considering both novel, predicted functional alleles as well as known, actionable CYP alleles reveals that rare, deleterious variation contributes markedly to the overall burden of pharmacogenetic alleles within the populations considered, and that the contribution of rare variation to this burden is over three times greater in AA individuals as compared with Caucasians. While most of these impactful alleles are individually rare, 7.6–11.7% of individuals interrogated in the study carry at least one newly described potentially deleterious alleles in a major drug-metabolizing CYP. PMID:24282029

  7. Quantifying rare, deleterious variation in 12 human cytochrome P450 drug-metabolism genes in a large-scale exome dataset.

    PubMed

    Gordon, Adam S; Tabor, Holly K; Johnson, Andrew D; Snively, Beverly M; Assimes, Themistocles L; Auer, Paul L; Ioannidis, John P A; Peters, Ulrike; Robinson, Jennifer G; Sucheston, Lara E; Wang, Danxin; Sotoodehnia, Nona; Rotter, Jerome I; Psaty, Bruce M; Jackson, Rebecca D; Herrington, David M; O'Donnell, Christopher J; Reiner, Alexander P; Rich, Stephen S; Rieder, Mark J; Bamshad, Michael J; Nickerson, Deborah A

    2014-04-15

    The study of genetic influences on drug response and efficacy ('pharmacogenetics') has existed for over 50 years. Yet, we still lack a complete picture of how genetic variation, both common and rare, affects each individual's responses to medications. Exome sequencing is a promising alternative method for pharmacogenetic discovery as it provides information on both common and rare variation in large numbers of individuals. Using exome data from 2203 AA and 4300 Caucasian individuals through the NHLBI Exome Sequencing Project, we conducted a survey of coding variation within 12 Cytochrome P450 (CYP) genes that are collectively responsible for catalyzing nearly 75% of all known Phase I drug oxidation reactions. In addition to identifying many polymorphisms with known pharmacogenetic effects, we discovered over 730 novel nonsynonymous alleles across the 12 CYP genes of interest. These alleles include many with diverse functional effects such as premature stop codons, aberrant splicesites and mutations at conserved active site residues. Our analysis considering both novel, predicted functional alleles as well as known, actionable CYP alleles reveals that rare, deleterious variation contributes markedly to the overall burden of pharmacogenetic alleles within the populations considered, and that the contribution of rare variation to this burden is over three times greater in AA individuals as compared with Caucasians. While most of these impactful alleles are individually rare, 7.6-11.7% of individuals interrogated in the study carry at least one newly described potentially deleterious alleles in a major drug-metabolizing CYP.

  8. Lack of deleterious effect of slow-release sodium fluoride treatment on cortical bone histology and quality in osteoporotic patients

    NASA Technical Reports Server (NTRS)

    Zerwekh, J. E.; Antich, P. P.; Sakhaee, K.; Prior, J.; Gonzales, J.; Gottschalk, F.; Pak, C. Y.

    1992-01-01

    We evaluated the effects of intermittent slow-release sodium fluoride (SRNaF) and continuous calcium citrate therapy on cortical bone histology, reflection ultrasound velocity (material strength) and back-scattered electron image analysis (BEI) in 26 osteoporotic patients before and following therapy. All measurements were made on transiliac crest bone biopsies obtained before and following 2 years of therapy in each patient. For all 26 patients there were no significant changes in cortical bone histomorphometric parameters. In 15 patients in whom bone material quality was assessed by reflection ultrasound, there was no change in velocity (4000 +/- 227 SD to 4013 +/- 240 m/s). BEI disclosed no mineralization defects or the presence of woven bone. Mean atomic number (density) of bone increased slightly, but significantly (9.261 +/- 0.311 to 9.457 +/- 0.223, P = 0.031). While these changes are less marked than those observed for cancellous bone, they indicate that this form of therapy does not adversely affect cortical bone remodelling.

  9. Deleterious Effects of Intra-arterial Administration of Particulate Steroids on Microvascular Perfusion in a Mouse Model.

    PubMed

    Laemmel, Elisabeth; Segal, Nicolas; Mirshahi, Massoud; Azzazene, Dalel; Le Marchand, Sylvie; Wybier, Marc; Vicaut, Eric; Laredo, Jean-Denis

    2016-06-01

    Purpose To determine the in vivo effects of several particulate steroids on microvascular perfusion by using intravital microscopy in a mice model and to investigate the in vitro interactions between these particulate steroids and red blood cells (RBCs). Materials and Methods The study was conducted in agreement with the guidelines of the National Committee of Ethic Reflection on Animal Experimentation. By using intravital microscopy of mouse cremaster muscle, the in vivo effects of several particulate steroids on microvascular perfusion were assessed. Four to five mice were allocated to each of the following treatment groups: saline solution, dexamethasone sodium phosphate, a nonparticulate steroid, and the particulate steroids cortivazol, methylprednisolone, triamcinolone, and prednisolone. By using in vitro blood microcinematography and electron microscopy, the interactions between these steroids and human RBCs were studied. All results were analyzed by using nonparametric tests. Results With prednisolone, methylprednisolone, or triamcinolone, blood flow was rapidly and completely stopped in all the arterioles and venules (median RBC velocity in first-order arterioles, 5 minutes after administration was zero for these three groups) compared with a limited effect in mice treated with saline, dexamethasone, and cortivazol (20.3, 21.3, and 27.5 mm/sec, respectively; P < .003). This effect was associated with a large decrease in the functional capillary density (4.21, 0, and 0 capillaries per millimeter for methylprednisolone, triamcinolone, or prednisolone, respectively, vs 21.0, 21.4, and 19.1 capillaries per millimeter in mice treated with saline, dexamethasone, and cortivazol, respectively; P < .003). This was because of the rapid formation of RBC aggregates. However, no change in microvascular perfusion was associated with administration of cortivazol or dexamethasone. In vitro experiments confirmed the formation of RBC aggregates associated with the

  10. Pantoea agglomerans: a mysterious bacterium of evil and good. Part III. Deleterious effects: infections of humans, animals and plants.

    PubMed

    Dutkiewicz, Jacek; Mackiewicz, Barbara; Kinga Lemieszek, Marta; Golec, Marcin; Milanowski, Janusz

    2016-06-02

    Pantoea agglomerans, a bacterium associated with plants, is not an obligate infectious agent in humans. However, it could be a cause of opportunistic human infections, mostly by wound infection with plant material, or as a hospital-acquired infection, mostly in immunocompromised individuals. Wound infection with P. agglomerans usually follow piercing or laceration of skin with a plant thorn, wooden splinter or other plant material and subsequent inoculation of the plant-residing bacteria, mostly during performing of agricultural occupations and gardening, or children playing. Septic arthritis or synovitis appears as a common clinical outcome of exogenous infection with P. agglomerans, others include endophthalmitis, periostitis, endocarditis and osteomyelitis. Another major reason for clinical infection with P. agglomerans is exposure of hospitalized, often immunodeficient individuals to medical equipment or fluids contaminated with this bacterium. Epidemics of nosocomial septicemia with fatal cases have been described in several countries, both in adult and paediatric patients. In most cases, however, the clinical course of the hospital-acquired disease was mild and application of the proper antibiotic treatment led to full recovery. Compared to humans, there are only few reports on infectious diseases caused by Pantoea agglomerans in vertebrate animals. This species has been identified as a possible cause of equine abortion and placentitis and a haemorrhagic disease in dolphin fish (Coryphaena hippurus). P. agglomerans strains occur commonly, usually as symbionts, in insects and other arthropods. Pantoea agglomerans usually occurs in plants as an epi- or endophytic symbiont, often as mutualist. Nevertheless, this species has also also been identified as a cause of diseases in a range of cultivable plants, such as cotton, sweet onion, rice, maize, sorghum, bamboo, walnut, an ornamental plant called Chinese taro (Alocasia cucullata), and a grass called onion couch

  11. N-acetylcycsteine attenuates the deleterious effects of radiation therapy on inci-sional wound healing in rats

    PubMed Central

    Tascilar, O; Çakmak, GK; Emre, AU; Bakkal, H; Kandemir, N; Turkcu, UO; Demir, EO

    2014-01-01

    Background: During preoperative radiotherapy, effective doses of ionizing radiation occasionally cause wound complications after subsequent surgery. This study was designed to determine the effects of intraperitoneally or orally administered N-acetylcysteine (NAC) on anastomotic healing of irradiated rats. Material & Methods: Forty Wistar albino rats were randomized into four groups containing 10 rats each. A 3 cm long surgical full-thickness midline laparotomy was performed to all groups (Groups 1-4). Group 1 was designed as a control group without radiation therapy and NAC treatment. Groups 2, 3 and 4 received a single abdominal dose of 10 Gy irradiation before laparotomy and groups 3 and 4 received oral and intraperitoneal NAC, respectively. Results: Group comparisons demonstrated that breaking strength was significantly higher in NAC treated rats. A statistically significant difference was determined in terms of superoxide dismutase (SOD), malondealdehyde (MDA) and glutation (GSH) values between groups (p<0.001). Nevertheless, advanced oxidation protein products (AOPP) levels were found to be similar between groups (p=0.163). Serum GSH and SOD levels were significantly higher in groups 3 and 4 when compared to group 2 (p < 0.05). Similarly, there was a significant increase in serum MDA concentration, predicting lipid peroxidation, in group 2 when compared to groups 1, 3 and 4 (p < 0.05). There was not a significant difference between Groups 3 and 4 regarding GSH, MDA, SOD, and AOPP levels. Histopathological analysis revealed that NAC administration, either orally or intraperitoneally, leads to a better incisional healing in terms of inflammation, granulation, collagen deposition, reepithelization and neovascularization. Conclusion: The present study supports the hypothesis that NAC administration alleviates the negative effects of radiotherapy on incisional wound healing by means of reducing oxidative stress markers and improving histologic parameters

  12. Spectrum of BRCA1/2 variants in 940 patients from Argentina including novel, deleterious and recurrent germline mutations: impact on healthcare and clinical practice.

    PubMed

    Solano, Angela Rosaria; Cardoso, Florencia Cecilia; Romano, Vanesa; Perazzo, Florencia; Bas, Carlos; Recondo, Gonzalo; Santillan, Francisco Bernardo; Gonzalez, Eduardo; Abalo, Eduardo; Viniegra, María; Michel, José Davalos; Nuñez, Lina María; Noblia, Cristina Maria; Mc Lean, Ignacio; Canton, Enrique Diaz; Chacon, Reinaldo Daniel; Cortese, Gustavo; Varela, Eduardo Beccar; Greco, Martín; Barrientos, María Laura; Avila, Silvia Adela; Vuotto, Hector; Lorusso, Antonio; Podesta, Ernesto Jorge; Mando, Oscar Gaspar

    2016-07-24

    BRCA1/2 mutations in Latin America are scarcely documented and in serious need of knowledge about the spectrum of BRCA pathogenic variants, information which may alter clinical practice and subsequently improve patient outcome. In addition, the search for data on testing policies in different regions constitutes a fundamental strength for the present study, which analyzes BRCA1/2 gene sequences and large rearrangements in 940 probands with familial and/or personal history of breast/ovary cancer (BOC). In non-mutated DNA samples, Multiplex Ligation-dependent Probe Amplification assays (MLPA) were used for the analysis of large rearrangements.Our studies detected 179 deleterious mutations out of 940 (19.04%) probands, including 5 large rearrangements and 22 novel mutations. The recurrent mutations accounted for 15.08% of the total and only 2.87% of the probands analyzed, very different from a Hispanic panel previously described.

  13. Protective coatings for sensitive materials

    DOEpatents

    Egert, C.M.

    1997-08-05

    An enhanced protective coating is disclosed to prevent interaction between constituents of the environment and devices that can be damaged by those constituents. This coating is provided by applying a synergistic combination of diffusion barrier and physical barrier materials. These materials can be, for example, in the form of a plurality of layers of a diffusion barrier and a physical barrier, with these barrier layers being alternated. Further protection in certain instances is provided by including at least one layer of a getter material to actually react with one or more of the deleterious constituents. The coating is illustrated by using alternating layers of an organic coating (such as Parylene-C{trademark}) as the diffusion barrier, and a metal coating (such as aluminum) as the physical barrier. For best results there needs to be more than one of at least one of the constituent layers. 4 figs.

  14. Protective coatings for sensitive materials

    DOEpatents

    Egert, Charles M.

    1997-01-01

    An enhanced protective coating to prevent interaction between constituents of the environment and devices that can be damaged by those constituents. This coating is provided by applying a synergistic combination of diffusion barrier and physical barrier materials. These materials can be, for example, in the form of a plurality of layers of a diffusion barrier and a physical barrier, with these barrier layers being alternated. Further protection in certain instances is provided by including at least one layer of a getter material to actually react with one or more of the deleterious constituents. The coating is illustrated by using alternating layers of an organic coating (such as Parylene-C.TM.) as the diffusion barrier, and a metal coating (such as aluminum) as the physical barrier. For best results there needs to be more than one of at least one of the constituent layers.

  15. Analysis of Repair Mechanisms following an Induced Double-Strand Break Uncovers Recessive Deleterious Alleles in the Candida albicans Diploid Genome.

    PubMed

    Feri, Adeline; Loll-Krippleber, Raphaël; Commere, Pierre-Henri; Maufrais, Corinne; Sertour, Natacha; Schwartz, Katja; Sherlock, Gavin; Bougnoux, Marie-Elisabeth; d'Enfert, Christophe; Legrand, Mélanie

    2016-10-11

    The diploid genome of the yeast Candida albicans is highly plastic, exhibiting frequent loss-of-heterozygosity (LOH) events. To provide a deeper understanding of the mechanisms leading to LOH, we investigated the repair of a unique DNA double-strand break (DSB) in the laboratory C. albicans SC5314 strain using the I-SceI meganuclease. Upon I-SceI induction, we detected a strong increase in the frequency of LOH events at an I-SceI target locus positioned on chromosome 4 (Chr4), including events spreading from this locus to the proximal telomere. Characterization of the repair events by single nucleotide polymorphism (SNP) typing and whole-genome sequencing revealed a predominance of gene conversions, but we also observed mitotic crossover or break-induced replication events, as well as combinations of independent events. Importantly, progeny that had undergone homozygosis of part or all of Chr4 haplotype B (Chr4B) were inviable. Mining of genome sequencing data for 155 C. albicans isolates allowed the identification of a recessive lethal allele in the GPI16 gene on Chr4B unique to C. albicans strain SC5314 which is responsible for this inviability. Additional recessive lethal or deleterious alleles were identified in the genomes of strain SC5314 and two clinical isolates. Our results demonstrate that recessive lethal alleles in the genomes of C. albicans isolates prevent the occurrence of specific extended LOH events. While these and other recessive lethal and deleterious alleles are likely to accumulate in C. albicans due to clonal reproduction, their occurrence may in turn promote the maintenance of corresponding nondeleterious alleles and, consequently, heterozygosity in the C. albicans species.

  16. Albumin infusion may deleteriously promote extracellular fluid overload without improving circulating hypovolemia in patients of advanced cirrhosis with diabetes mellitus and sepsis.

    PubMed

    Kumar, Ramesh; Kumar, Sachin; Lata, Suman

    2013-04-01

    In patients with liver cirrhosis, albumin is given to improve relative hypovolemia caused by marked splanchnic arteriolar vasodilatation. However, the volume effect of albumin is not predictable and depends also on capillary permeability, hydrostatic pressure and lymphatic ability to re-circulate albumin from interstitium to plasma. In patients with decompensated cirrhosis, the capillary permeability is increased, hydrostatic pressure is higher, and the lymphatics functions are deficient. Hence the albumin molecules are more likely to be extravasated rapidly into the interstitium and are subsequently less likely to be re-circulated back into the plasma. This would not only fail to correct circulating hypovolemia, the purpose for which it is given, but also would favor development of reverse colloid oncotic pressure and fluid movement out of the capillaries leading to development of edema. Thus, anything else which could further increase capillary permeability or hydrostatic pressure in cirrhotic patients might create more problems with albumin infusion. An increased capillary permeability is the hallmark of diabetes mellitus. Furthermore, diabetes mellitus may worsen immunodepression in cirrhotic patients thus increasing the incidence of severe infections which may further have a deleterious effect on hemodynamics and capillary permeability. A diabetic patient with advanced cirrhosis and sepsis usually has markedly increased capillary permeability, high hydrostatic pressure due to hyperdynamic circulation, and compromised lymphatic drainage capacity. Hence, using albumin infusion in them would not only fail to improve relative hypovolemia, but also would deleteriously promote extravascular accumulation of fluid, which might impair the functions of many vital organs. However, the efficacy and safety of albumin infusion in diabetic patients with advanced cirrhosis and sepsis is not known. Such data can have a great clinical implication and would necessitate search of

  17. Deleterious Rare Variants Reveal Risk for Loss of GABAA Receptor Function in Patients with Genetic Epilepsy and in the General Population

    PubMed Central

    Hernandez, Ciria C.; Klassen, Tara L.; Jackson, Laurel G.; Gurba, Katharine; Hu, Ningning; Macdonald, Robert L.

    2016-01-01

    Genetic epilepsies (GEs) account for approximately 50% of all seizure disorders, and familial forms include mutations in single GABAA receptor subunit genes (GABRs). In 144 sporadic GE cases (GECs), exome sequencing of 237 ion channel genes identified 520 GABR variants. Among these variants, 33 rare variants in 11 GABR genes were present in 24 GECs. To assess functional risk of variants in GECs, we selected 8 variants found in GABRA, 3 in GABRB, and 3 in GABRG and compared them to 18 variants found in the general population for GABRA1 (n = 9), GABRB3 (n = 7), and GABRG2 (n = 2). To identify deleterious variants and gain insight into structure-function relationships, we studied the gating properties, surface expression and structural perturbations of the 32 variants. Significant reduction of GABAA receptor function was strongly associated with variants scored as deleterious and mapped within the N-terminal and transmembrane domains. In addition, 12 out of 17 variants mapped along the β+/α- GABA binding interface, were associated with reduction in channel gating and were predicted to cause structural rearrangements of the receptor by in silico simulations. Missense or nonsense mutations of GABRA1, GABRB3 and GABRG2 primarily impair subunit biogenesis. In contrast, GABR variants affected receptor function by impairing gating, suggesting that different mechanisms are operating in GABR epilepsy susceptibility variants and disease-causing mutations. The functional impact of single GABR variants found in individuals with sporadic GEs warrants the use of molecular diagnosis and will ultimately improve the treatment of genetic epilepsies by using a personalized approach. PMID:27622563

  18. In silico analysis of the deleterious nsSNPs (missense) in the homeobox domain of human HOXB13 gene responsible for hereditary prostate cancer.

    PubMed

    Chandrasekaran, Gopalakrishnan; Hwang, Eu Chang; Kang, Taek Won; Kwon, Dong Deuk; Park, Kwangsung; Lee, Je-Jung; Lakshmanan, Vinoth-Kumar

    2017-01-10

    The human HOXB13 gene encodes a transcription factor containing a DNA-binding homeobox domain and a HoxA13 N-terminal domain. SNP is considered to be the primary genetic cause for hereditary prostate cancer (PCa). The study of functional nsSNPs would give an insight into the exact cause underlying the onset of hereditary PCa and possible methodologies for the cure or early management of the disease. Several in silico tools were used to screen and map the deleterious nsSNPs to the protein structure for predicting the structure-function effects. Among the 23 homeobox nsSNPs, sift predicted 20, whereas PolyPhen, panther, and provean predicted 21 nsSNP's as deleterious. W63R, D244N, K239Q, P222R, K218R, and G216C were found to have higher energy values than the native 2CRA. The RMSD value showed increased deviation for T253P(2.53 Å), P222R(2.27 Å), G216C(2.15 Å), K218R(1.66 Å), and K239Q(1.62 Å). The I-Mutant showed increase in the stability of R258C, S254T, S250L, K239Q, and Q227E. Ramachandran plot showed mutants P222R, G216C, W263R, and K218R having drastically unfavorable pattern of amino acid residues. The presence of these mutations may result in the altered structure and function of the transcription factor; however, the exact mechanism and pathology of those predicted nsSNPs should further be validated by in vivo experiments and population-based studies.

  19. Analysis of Repair Mechanisms following an Induced Double-Strand Break Uncovers Recessive Deleterious Alleles in the Candida albicans Diploid Genome

    PubMed Central

    Feri, Adeline; Loll-Krippleber, Raphaël; Commere, Pierre-Henri; Maufrais, Corinne; Sertour, Natacha; Schwartz, Katja; Sherlock, Gavin; Bougnoux, Marie-Elisabeth

    2016-01-01

    ABSTRACT The diploid genome of the yeast Candida albicans is highly plastic, exhibiting frequent loss-of-heterozygosity (LOH) events. To provide a deeper understanding of the mechanisms leading to LOH, we investigated the repair of a unique DNA double-strand break (DSB) in the laboratory C. albicans SC5314 strain using the I-SceI meganuclease. Upon I-SceI induction, we detected a strong increase in the frequency of LOH events at an I-SceI target locus positioned on chromosome 4 (Chr4), including events spreading from this locus to the proximal telomere. Characterization of the repair events by single nucleotide polymorphism (SNP) typing and whole-genome sequencing revealed a predominance of gene conversions, but we also observed mitotic crossover or break-induced replication events, as well as combinations of independent events. Importantly, progeny that had undergone homozygosis of part or all of Chr4 haplotype B (Chr4B) were inviable. Mining of genome sequencing data for 155 C. albicans isolates allowed the identification of a recessive lethal allele in the GPI16 gene on Chr4B unique to C. albicans strain SC5314 which is responsible for this inviability. Additional recessive lethal or deleterious alleles were identified in the genomes of strain SC5314 and two clinical isolates. Our results demonstrate that recessive lethal alleles in the genomes of C. albicans isolates prevent the occurrence of specific extended LOH events. While these and other recessive lethal and deleterious alleles are likely to accumulate in C. albicans due to clonal reproduction, their occurrence may in turn promote the maintenance of corresponding nondeleterious alleles and, consequently, heterozygosity in the C. albicans species. PMID:27729506

  20. Weathering of Roofing Materials-An Overview

    SciTech Connect

    Berdahl, Paul; Akbari, Hashem; Levinson, Ronnen; Miller, William A.

    2006-03-30

    An overview of several aspects of the weathering of roofing materials is presented. Degradation of materials initiated by ultraviolet radiation is discussed for plastics used in roofing, as well as wood and asphalt. Elevated temperatures accelerate many deleterious chemical reactions and hasten diffusion of material components. Effects of moisture include decay of wood, acceleration of corrosion of metals, staining of clay, and freeze-thaw damage. Soiling of roofing materials causes objectionable stains and reduces the solar reflectance of reflective materials. (Soiling of non-reflective materials can also increase solar reflectance.) Soiling can be attributed to biological growth (e.g., cyanobacteria, fungi, algae), deposits of organic and mineral particles, and to the accumulation of flyash, hydrocarbons and soot from combustion.

  1. Spectrum and characterisation of BRCA1 and BRCA2 deleterious mutations in high-risk Czech patients with breast and/or ovarian cancer

    PubMed Central

    Machackova, Eva; Foretova, Lenka; Lukesova, Mirka; Vasickova, Petra; Navratilova, Marie; Coene, Ilse; Pavlu, Hana; Kosinova, Veronika; Kuklova, Jitka; Claes, Kathleen

    2008-01-01

    Background The incidence of breast cancer has doubled over the past 20 years in the Czech Republic. Hereditary factors may be a cause of young onset, bilateral breast or ovarian cancer, and familial accumulation of the disease. BRCA1 and BRCA2 mutations account for an important fraction of hereditary breast and ovarian cancer cases. One thousand and ten unrelated high-risk probands with breast and/or ovarian cancer were analysed for the presence of a BRCA1 or BRCA2 gene mutation at the Masaryk Memorial Cancer Institute (Czech Republic) during 1999–2006. Methods The complete coding sequences and splice sites of both genes were screened, and the presence of large intragenic rearrangements in BRCA1 was verified. Putative splice-site variants were analysed at the cDNA level for their potential to alter mRNA splicing. Results In 294 unrelated families (29.1% of the 1,010 probands) pathogenic mutations were identified, with 44 different BRCA1 mutations and 41 different BRCA2 mutations being detected in 204 and 90 unrelated families, respectively. In total, three BRCA1 founder mutations (c.5266dupC; c.3700_3704del5; p.Cys61Gly) and two BRCA2 founder mutations (c.7913_7917del5; c.8537_8538del2) represent 52% of all detected mutations in Czech high-risk probands. Nine putative splice-site variants were evaluated at the cDNA level. Three splice-site variants in BRCA1 (c.302-3C>G; c.4185G>A and c.4675+1G>A) and six splice-site variants in BRCA2 (c.475G>A; c.476-2>G; c.7007G>A; c.8755-1G>A; c.9117+2T>A and c.9118-2A>G) were demonstrated to result in aberrant transcripts and are considered as deleterious mutations. Conclusion This study represents an evaluation of deleterious genetic variants in the BRCA1 and 2 genes in the Czech population. The classification of several splice-site variants as true pathogenic mutations may prove useful for genetic counselling of families with high risk of breast and ovarian cancer. PMID:18489799

  2. Protective Effect of Parsley Juice (Petroselinum crispum, Apiaceae) against Cadmium Deleterious Changes in the Developed Albino Mice Newborns (Mus musculus) Brain

    PubMed Central

    Allam, Ahmed A.; Maodaa, Salah N.; Abo-Eleneen, Rasha; Ajarem, Jamaan

    2016-01-01

    Parsley was used as a probe of the current experiment to prevent the behavioral, morphological and biochemical changes in the newborn brain following the administration of cadmium (Cd) to the pregnant mice. The nonanesthetized pregnant mice were given daily parsley juice (Petroselinum crispum) at doses of 20 mg/kg and 10 mg/kg. Pregnant mothers were given Cd at a dose of 30 mg/kg divided into 3 equal times. The newborns have been divided into 6 groups: Group A, mothers did not take treatment; Groups B and C, mothers were treated with low and high dose of parsley, respectively; Group D, mothers were treated only with Cd (perinatal intoxication); Groups E and F, mothers were treated with Cd doses and protected by low and high doses of parsley, respectively. Light microscopy showed that Cd-induced neuronal degeneration by chromatolysis and pyknosis in the brain regions. The low dose of parsley 10 g/kg/day exhibited significant effects in neutralizing and reducing the deleterious changes due to Cd exposure during pregnancy on the behavioral activities, neurotransmitters, oxidative stress, and brain neurons morphology of the mice newborns. PMID:26966507

  3. Protective Effect of Parsley Juice (Petroselinum crispum, Apiaceae) against Cadmium Deleterious Changes in the Developed Albino Mice Newborns (Mus musculus) Brain.

    PubMed

    Allam, Ahmed A; Maodaa, Salah N; Abo-Eleneen, Rasha; Ajarem, Jamaan

    2016-01-01

    Parsley was used as a probe of the current experiment to prevent the behavioral, morphological and biochemical changes in the newborn brain following the administration of cadmium (Cd) to the pregnant mice. The nonanesthetized pregnant mice were given daily parsley juice (Petroselinum crispum) at doses of 20 mg/kg and 10 mg/kg. Pregnant mothers were given Cd at a dose of 30 mg/kg divided into 3 equal times. The newborns have been divided into 6 groups: Group A, mothers did not take treatment; Groups B and C, mothers were treated with low and high dose of parsley, respectively; Group D, mothers were treated only with Cd (perinatal intoxication); Groups E and F, mothers were treated with Cd doses and protected by low and high doses of parsley, respectively. Light microscopy showed that Cd-induced neuronal degeneration by chromatolysis and pyknosis in the brain regions. The low dose of parsley 10 g/kg/day exhibited significant effects in neutralizing and reducing the deleterious changes due to Cd exposure during pregnancy on the behavioral activities, neurotransmitters, oxidative stress, and brain neurons morphology of the mice newborns.

  4. Genotyping of a family with a novel deleterious DPYD mutation supports the pretherapeutic screening of DPD deficiency with dihydrouracil/uracil ratio.

    PubMed

    Thomas, F; Hennebelle, I; Delmas, C; Lochon, I; Dhelens, C; Garnier Tixidre, C; Bonadona, A; Penel, N; Goncalves, A; Delord, J P; Toulas, C; Chatelut, E

    2016-02-01

    Despite the growing evidence that dihydropyrimidine dehydrogenase deficiency (DPD, encoded by the DPYD gene) confers a higher risk of developing severe toxicity, most patients are not screened for DPD deficiency before fluoropyrimidine treatment. We report here the genetic and phenotypic analyses of DPD in a family related to a patient who died after a first cycle of 5-fluorouracil and in 15 additional retrospective patients having a partial DPD deficiency (as measured by plasma dihydrouracil/uracil ratio). The patient with lethal toxicity was found to be a compound heterozygote for two DPYD mutations: a novel 8-bp duplication (c.168_175dupGAATAATT, p.Phe59Ter) and c.1679T>G (Ile560Ser). The patient's dihydrouracil/uracil ratio indicates complete DPD deficiency. The novel mutation was found in two members of the patient's family. Deleterious DPYD mutations were identified in 9 out of the 15 patients. The relationship between genotype and dihydrouracil/uracil values in the 22 patients of the present study was significant (P = 0.01).

  5. Cannabidiol provides long-lasting protection against the deleterious effects of inflammation in a viral model of multiple sclerosis: a role for A2A receptors.

    PubMed

    Mecha, M; Feliú, A; Iñigo, P M; Mestre, L; Carrillo-Salinas, F J; Guaza, C

    2013-11-01

    Inflammation in the central nervous system (CNS) is a complex process that involves a multitude of molecules and effectors, and it requires the transmigration of blood leukocytes across the blood-brain barrier (BBB) and the activation of resident immune cells. Cannabidiol (CBD), a non-psychotropic cannabinoid constituent of Cannabis sativa, has potent anti-inflammatory and immunosuppressive properties. Yet, how this compound modifies the deleterious effects of inflammation in TMEV-induced demyelinating disease (TMEV-IDD) remains unknown. Using this viral model of multiple sclerosis (MS), we demonstrate that CBD decreases the transmigration of blood leukocytes by downregulating the expression of vascular cell adhesion molecule-1 (VCAM-1), chemokines (CCL2 and CCL5) and the proinflammatory cytokine IL-1β, as well as by attenuating the activation of microglia. Moreover, CBD administration at the time of viral infection exerts long-lasting effects, ameliorating motor deficits in the chronic phase of the disease in conjunction with reduced microglial activation and pro-inflammatory cytokine production. Adenosine A2A receptors participate in some of the anti-inflammatory effects of CBD, as the A2A antagonist ZM241385 partially blocks the protective effects of CBD in the initial stages of inflammation. Together, our findings highlight the anti-inflammatory effects of CBD in this viral model of MS and demonstrate the significant therapeutic potential of this compound for the treatment of pathologies with an inflammatory component.

  6. Welding of Materials for Energy Applications

    NASA Astrophysics Data System (ADS)

    DuPont, John N.; Babu, Suresh; Liu, Stephen

    2013-07-01

    Materials will play a critical role in power generation from both new and existing plants that rely on coal, nuclear, and oil/gas as energy supplies. High efficiency power plants are currently being designed that will require materials with improved mechanical properties and corrosion resistance under conditions of elevated temperature, stress, and aggressive gaseous environments. Most of these materials will require welding during initial fabrication and plant maintenance. The severe thermal and strain cycles associated with welding can produce large gradients in microstructure and composition within the heat-affected and fusion zones of the weld, and these gradients are commonly accompanied by deleterious changes to properties. Thus, successful use of materials in energy applications hinges on the ability to understand, predict, and control the processing-microstructure-property relations during welding. This article highlights some of the current challenges associated with fusion welding of materials for energy applications.

  7. β1-C121W Is Down But Not Out: Epilepsy-Associated Scn1b-C121W Results in a Deleterious Gain-of-Function

    PubMed Central

    Kruger, Larisa C.; O'Malley, Heather A.; Hull, Jacob M.; Kleeman, Amanda; Patino, Gustavo A.

    2016-01-01

    Voltage-gated sodium channel (VGSC) β subunits signal through multiple pathways on multiple time scales. In addition to modulating sodium and potassium currents, β subunits play nonconducting roles as cell adhesion molecules, which allow them to function in cell–cell communication, neuronal migration, neurite outgrowth, neuronal pathfinding, and axonal fasciculation. Mutations in SCN1B, encoding VGSC β1 and β1B, are associated with epilepsy. Autosomal-dominant SCN1B-C121W, the first epilepsy-associated VGSC mutation identified, results in genetic epilepsy with febrile seizures plus (GEFS+). This mutation has been shown to disrupt both the sodium-current-modulatory and cell-adhesive functions of β1 subunits expressed in heterologous systems. The goal of this study was to compare mice heterozygous for Scn1b-C121W (Scn1b+/W) with mice heterozygous for the Scn1b-null allele (Scn1b+/−) to determine whether the C121W mutation results in loss-of-function in vivo. We found that Scn1b+/W mice were more susceptible than Scn1b+/− and Scn1b+/+ mice to hyperthermia-induced convulsions, a model of pediatric febrile seizures. β1-C121W subunits are expressed at the neuronal cell surface in vivo. However, despite this, β1-C121W polypeptides are incompletely glycosylated and do not associate with VGSC α subunits in the brain. β1-C121W subcellular localization is restricted to neuronal cell bodies and is not detected at axon initial segments in the cortex or cerebellum or at optic nerve nodes of Ranvier of Scn1bW/W mice. These data, together with our previous results showing that β1-C121W cannot participate in trans-homophilic cell adhesion, lead to the hypothesis that SCN1B-C121W confers a deleterious gain-of-function in human GEFS+ patients. SIGNIFICANCE STATEMENT The mechanisms underlying genetic epilepsy syndromes are poorly understood. Closing this gap in knowledge is essential to the development of new medicines to treat epilepsy. We have used mouse models to

  8. Mutation-Structure-Function Relationship Based Integrated Strategy Reveals the Potential Impact of Deleterious Missense Mutations in Autophagy Related Proteins on Hepatocellular Carcinoma (HCC): A Comprehensive Informatics Approach

    PubMed Central

    Awan, Faryal Mehwish; Obaid, Ayesha; Ikram, Aqsa; Janjua, Hussnain Ahmed

    2017-01-01

    Autophagy, an evolutionary conserved multifaceted lysosome-mediated bulk degradation system, plays a vital role in liver pathologies including hepatocellular carcinoma (HCC). Post-translational modifications (PTMs) and genetic variations in autophagy components have emerged as significant determinants of autophagy related proteins. Identification of a comprehensive spectrum of genetic variations and PTMs of autophagy related proteins and their impact at molecular level will greatly expand our understanding of autophagy based regulation. In this study, we attempted to identify high risk missense mutations that are highly damaging to the structure as well as function of autophagy related proteins including LC3A, LC3B, BECN1 and SCD1. Number of putative structural and functional residues, including several sites that undergo PTMs were also identified. In total, 16 high-risk SNPs in LC3A, 18 in LC3B, 40 in BECN1 and 43 in SCD1 were prioritized. Out of these, 2 in LC3A (K49A, K51A), 1 in LC3B (S92C), 6 in BECN1 (S113R, R292C, R292H, Y338C, S346Y, Y352H) and 6 in SCD1 (Y41C, Y55D, R131W, R135Q, R135W, Y151C) coincide with potential PTM sites. Our integrated analysis found LC3B Y113C, BECN1 I403T, SCD1 R126S and SCD1 Y218C as highly deleterious HCC-associated mutations. This study is the first extensive in silico mutational analysis of the LC3A, LC3B, BECN1 and SCD1 proteins. We hope that the observed results will be a valuable resource for in-depth mechanistic insight into future investigations of pathological missense SNPs using an integrated computational platform. PMID:28085066

  9. Overproduction of the rbo gene product from Desulfovibrio species suppresses all deleterious effects of lack of superoxide dismutase in Escherichia coli.

    PubMed Central

    Pianzzola, M J; Soubes, M; Touati, D

    1996-01-01

    In an attempt to isolate the superoxide dismutase (SOD) gene from the anaerobic sulfate-reducing bacterium Desulfoarculus baarsii, a DNA fragment was isolated which functionally complemented an Escherichia coli mutant (sodA sodB) deficient in cytoplasmic SODs. This region carries two open reading frames with sequences which are very similar to that of the rbo-rub operon from Desulfovibrio vulgaris. Independent expression of the rbo and rub genes from ptac showed that expression of rbo was responsible for the observed phenotype. rbo overexpression suppressed all deleterious effects of SOD deficiency in E. coli, including inactivation by superoxide of enzymes containing 4Fe-4S clusters and DNA damage produced via the superoxide-enhanced Fenton reaction. Thus, rbo restored to the sodA sodB mutant the ability to grow on minimal medium without the addition of branched amino acids, and growth on gluconate and succinate carbon sources was no longer impaired. The spontaneous mutation rate, which is elevated in SOD-deficient mutants, returned to the wild-type level in the presence of Rbo, which also restored aerobic viability of sodA sodB recA mutants. Rbo from Desulfovibrio vulgaris, but not Desulfovibrio gigas desulforedoxin, which corresponds to the NH2-terminal domain of Rbo, complemented sod mutants. The physiological role of Rbo in sulfate-reducing bacteria is unknown. In E. coli, Rbo may permit the bacterium to avoid superoxide stress by maintaining functional (reduced) superoxide sensitive 4Fe-4S clusters. It would thereby restore enzyme activities and prevent the release of iron that occurs after cluster degradation and presumably leads to DNA damage. PMID:8955290

  10. Pharmacological activation of CB2 receptors counteracts the deleterious effect of ethanol on cell proliferation in the main neurogenic zones of the adult rat brain

    PubMed Central

    Rivera, Patricia; Blanco, Eduardo; Bindila, Laura; Alen, Francisco; Vargas, Antonio; Rubio, Leticia; Pavón, Francisco J.; Serrano, Antonia; Lutz, Beat; Rodríguez de Fonseca, Fernando; Suárez, Juan

    2015-01-01

    Chronic alcohol exposure reduces endocannabinoid activity and disrupts adult neurogenesis in rodents, which results in structural and functional alterations. Cannabinoid receptor agonists promote adult neural progenitor cell (NPC) proliferation. We evaluated the protective effects of the selective CB1 receptor agonist ACEA, the selective CB2 receptor agonist JWH133 and the fatty-acid amide-hydrolase (FAAH) inhibitor URB597, which enhances endocannabinoid receptor activity, on NPC proliferation in rats with forced consumption of ethanol (10%) or sucrose liquid diets for 2 weeks. We performed immunohistochemical and stereological analyses of cells expressing the mitotic phosphorylation of histone-3 (phospho-H3+) and the replicating cell DNA marker 5-bromo-2'-deoxyuridine (BrdU+) in the main neurogenic zones of adult brain: subgranular zone of dentate gyrus (SGZ), subventricular zone of lateral ventricles (SVZ) and hypothalamus. Animals were allowed ad libitum ethanol intake (7.3 ± 1.1 g/kg/day) after a controlled isocaloric pair-feeding period of sucrose and alcoholic diets. Alcohol intake reduced the number of BrdU+ cells in SGZ, SVZ, and hypothalamus. The treatments (URB597, ACEA, JWH133) exerted a differential increase in alcohol consumption over time, but JWH133 specifically counteracted the deleterious effect of ethanol on NPC proliferation in the SVZ and SGZ, and ACEA reversed this effect in the SGZ only. JWH133 also induced an increased number of BrdU+ cells expressing neuron-specific β3-tubulin in the SVZ and SGZ. These results indicated that the specific activation of CB2 receptors rescued alcohol-induced impaired NPC proliferation, which is a potential clinical interest for the risk of neural damage in alcohol dependence. PMID:26483633

  11. Pharmacological activation of CB2 receptors counteracts the deleterious effect of ethanol on cell proliferation in the main neurogenic zones of the adult rat brain.

    PubMed

    Rivera, Patricia; Blanco, Eduardo; Bindila, Laura; Alen, Francisco; Vargas, Antonio; Rubio, Leticia; Pavón, Francisco J; Serrano, Antonia; Lutz, Beat; Rodríguez de Fonseca, Fernando; Suárez, Juan

    2015-01-01

    Chronic alcohol exposure reduces endocannabinoid activity and disrupts adult neurogenesis in rodents, which results in structural and functional alterations. Cannabinoid receptor agonists promote adult neural progenitor cell (NPC) proliferation. We evaluated the protective effects of the selective CB1 receptor agonist ACEA, the selective CB2 receptor agonist JWH133 and the fatty-acid amide-hydrolase (FAAH) inhibitor URB597, which enhances endocannabinoid receptor activity, on NPC proliferation in rats with forced consumption of ethanol (10%) or sucrose liquid diets for 2 weeks. We performed immunohistochemical and stereological analyses of cells expressing the mitotic phosphorylation of histone-3 (phospho-H3+) and the replicating cell DNA marker 5-bromo-2'-deoxyuridine (BrdU+) in the main neurogenic zones of adult brain: subgranular zone of dentate gyrus (SGZ), subventricular zone of lateral ventricles (SVZ) and hypothalamus. Animals were allowed ad libitum ethanol intake (7.3 ± 1.1 g/kg/day) after a controlled isocaloric pair-feeding period of sucrose and alcoholic diets. Alcohol intake reduced the number of BrdU+ cells in SGZ, SVZ, and hypothalamus. The treatments (URB597, ACEA, JWH133) exerted a differential increase in alcohol consumption over time, but JWH133 specifically counteracted the deleterious effect of ethanol on NPC proliferation in the SVZ and SGZ, and ACEA reversed this effect in the SGZ only. JWH133 also induced an increased number of BrdU+ cells expressing neuron-specific β3-tubulin in the SVZ and SGZ. These results indicated that the specific activation of CB2 receptors rescued alcohol-induced impaired NPC proliferation, which is a potential clinical interest for the risk of neural damage in alcohol dependence.

  12. Mutation-Structure-Function Relationship Based Integrated Strategy Reveals the Potential Impact of Deleterious Missense Mutations in Autophagy Related Proteins on Hepatocellular Carcinoma (HCC): A Comprehensive Informatics Approach.

    PubMed

    Awan, Faryal Mehwish; Obaid, Ayesha; Ikram, Aqsa; Janjua, Hussnain Ahmed

    2017-01-11

    Autophagy, an evolutionary conserved multifaceted lysosome-mediated bulk degradation system, plays a vital role in liver pathologies including hepatocellular carcinoma (HCC). Post-translational modifications (PTMs) and genetic variations in autophagy components have emerged as significant determinants of autophagy related proteins. Identification of a comprehensive spectrum of genetic variations and PTMs of autophagy related proteins and their impact at molecular level will greatly expand our understanding of autophagy based regulation. In this study, we attempted to identify high risk missense mutations that are highly damaging to the structure as well as function of autophagy related proteins including LC3A, LC3B, BECN1 and SCD1. Number of putative structural and functional residues, including several sites that undergo PTMs were also identified. In total, 16 high-risk SNPs in LC3A, 18 in LC3B, 40 in BECN1 and 43 in SCD1 were prioritized. Out of these, 2 in LC3A (K49A, K51A), 1 in LC3B (S92C), 6 in BECN1 (S113R, R292C, R292H, Y338C, S346Y, Y352H) and 6 in SCD1 (Y41C, Y55D, R131W, R135Q, R135W, Y151C) coincide with potential PTM sites. Our integrated analysis found LC3B Y113C, BECN1 I403T, SCD1 R126S and SCD1 Y218C as highly deleterious HCC-associated mutations. This study is the first extensive in silico mutational analysis of the LC3A, LC3B, BECN1 and SCD1 proteins. We hope that the observed results will be a valuable resource for in-depth mechanistic insight into future investigations of pathological missense SNPs using an integrated computational platform.

  13. EEG theta/beta ratio as a potential biomarker for attentional control and resilience against deleterious effects of stress on attention.

    PubMed

    Putman, Peter; Verkuil, Bart; Arias-Garcia, Elsa; Pantazi, Ioanna; van Schie, Charlotte

    2014-06-01

    Anxious stress compromises cognitive executive performance. This occurs, for instance, in cognitive performance anxiety (CPA), in which anxiety about one's cognitive performance causes that performance to actually deteriorate (e.g., test anxiety). This is thought to result from a prefrontal cortically (PFC) mediated failure of top-down attentional control over stress-induced automatic processing of threat-related information. In addition, stress-induced increased catecholamine influx into the PFC may directly compromise attentional function. Previous research has suggested that the ratio between resting state electroencephalographic (EEG) low- and high-frequency power (the theta/beta ratio) is related to trait attentional control, which might moderate these effects of stress on attentional function. The goals of the present study were to test the novel prediction that theta/beta ratio moderates the deleterious effects of CPA-like anxious stress on state attentional control and to replicate a previous finding that the theta/beta ratio is related to self-reported trait attentional control. After recording of baseline frontal EEG signals, 77 participants performed a stress induction or a control procedure. Trait attentional control was assessed with the Attentional Control Scale, whereas stress-induced changes in attentional control and anxiety were measured with self-report visual analogue scales. The hypothesized moderating influence of theta/beta ratio on the effects of stress on state attentional control was confirmed. Theta/beta ratio explained 28% of the variance in stress-induced deterioration of self-reported attentional control. The negative relationship between theta/beta ratio and trait attentional control was replicated (r = -.33). The theta/beta ratio reflects, likely prefrontally mediated, attentional control, and should be a useful biomarker for the study of CPA and other anxiety-cognition interactions.

  14. Synthesis and evaluation of the potential deleterious effects of ZnO nanomaterials (nanoneedles and nanoflowers) on blood components, including albumin, erythrocytes and human isolated primary neutrophils

    NASA Astrophysics Data System (ADS)

    Pastrello, Bruna; Paracatu, Luana Chiquetto; de Carvalho Bertozo, Luiza; Paino, Iêda Maria Martinez; Lisboa-Filho, Paulo Noronha; Ximenes, Valdecir Farias

    2016-07-01

    The application of zinc oxide (ZnO) nanoparticles in biomaterials has increased significantly in the recent years. Here, we aimed to study the potential deleterious effects of ZnO on blood components, including human serum albumin (HSA), erythrocytes and human isolated primary neutrophils. To test the influence of the morphology of the nanomaterials, ZnO nanoneedles (ZnO-nn) and nanoflowers (ZnO-nf) were synthesized. The zeta potential and mean size of ZnO-nf and ZnO-nn suspensions in phosphate-buffered saline were -10.73 mV and 3.81 nm and -5.27 mV and 18.26 nm, respectively. The incubation of ZnO with HSA did not cause its denaturation as verified by the absence of significant alterations in the intrinsic and extrinsic fluorescence and in the circular dichroism spectrum of the protein. The capacity of HSA as a drug carrier was not affected as verified by employing site I and II fluorescent markers. Neither type of ZnO was able to provoke the activation of neutrophils, as verified by lucigenin- and luminol-dependent chemiluminescence and by the extracellular release of hydrogen peroxide. ZnO-nf, but not ZnO-nn, induced the haemolysis of erythrocytes. In conclusion, our results reinforce the concept that ZnO nanomaterials are relatively safe for usage in biomaterials. A potential exception is the capacity of ZnO-nf to promote the lysis of erythrocytes, a discovery that shows the importance of the morphology in the toxicity of nanoparticles.

  15. Detection of haplotypes associated with prenatal death in dairy cattle and identification of deleterious mutations in GART, SHBG and SLC37A2.

    PubMed

    Fritz, Sébastien; Capitan, Aurelien; Djari, Anis; Rodriguez, Sabrina C; Barbat, Anne; Baur, Aurélia; Grohs, Cécile; Weiss, Bernard; Boussaha, Mekki; Esquerré, Diane; Klopp, Christophe; Rocha, Dominique; Boichard, Didier

    2013-01-01

    The regular decrease of female fertility over time is a major concern in modern dairy cattle industry. Only half of this decrease is explained by indirect response to selection on milk production, suggesting the existence of other factors such as embryonic lethal genetic defects. Genomic regions harboring recessive deleterious mutations were detected in three dairy cattle breeds by identifying frequent haplotypes (>1%) showing a deficit in homozygotes among Illumina Bovine 50k Beadchip haplotyping data from the French genomic selection database (47,878 Holstein, 16,833 Montbéliarde, and 11,466 Normande animals). Thirty-four candidate haplotypes (p<10(-4)) including previously reported regions associated with Brachyspina, CVM, HH1, and HH3 in Holstein breed were identified. Haplotype length varied from 1 to 4.8 Mb and frequencies from 1.7 up to 9%. A significant negative effect on calving rate, consistent in heifers and in lactating cows, was observed for 9 of these haplotypes in matings between carrier bulls and daughters of carrier sires, confirming their association with embryonic lethal mutations. Eight regions were further investigated using whole genome sequencing data from heterozygous bull carriers and control animals (45 animals in total). Six strong candidate causative mutations including polymorphisms previously reported in FANCI (Brachyspina), SLC35A3 (CVM), APAF1 (HH1) and three novel mutations with very damaging effect on the protein structure, according to SIFT and Polyphen-2, were detected in GART, SHBG and SLC37A2 genes. In conclusion, this study reveals a yet hidden consequence of the important inbreeding rate observed in intensively selected and specialized cattle breeds. Counter-selection of these mutations and management of matings will have positive consequences on female fertility in dairy cattle.

  16. Detection of Haplotypes Associated with Prenatal Death in Dairy Cattle and Identification of Deleterious Mutations in GART, SHBG and SLC37A2

    PubMed Central

    Fritz, Sébastien; Capitan, Aurelien; Djari, Anis; Rodriguez, Sabrina C.; Barbat, Anne; Baur, Aurélia; Grohs, Cécile; Weiss, Bernard; Boussaha, Mekki; Esquerré, Diane; Klopp, Christophe; Rocha, Dominique; Boichard, Didier

    2013-01-01

    The regular decrease of female fertility over time is a major concern in modern dairy cattle industry. Only half of this decrease is explained by indirect response to selection on milk production, suggesting the existence of other factors such as embryonic lethal genetic defects. Genomic regions harboring recessive deleterious mutations were detected in three dairy cattle breeds by identifying frequent haplotypes (>1%) showing a deficit in homozygotes among Illumina Bovine 50k Beadchip haplotyping data from the French genomic selection database (47,878 Holstein, 16,833 Montbéliarde, and 11,466 Normande animals). Thirty-four candidate haplotypes (p<10−4) including previously reported regions associated with Brachyspina, CVM, HH1, and HH3 in Holstein breed were identified. Haplotype length varied from 1 to 4.8 Mb and frequencies from 1.7 up to 9%. A significant negative effect on calving rate, consistent in heifers and in lactating cows, was observed for 9 of these haplotypes in matings between carrier bulls and daughters of carrier sires, confirming their association with embryonic lethal mutations. Eight regions were further investigated using whole genome sequencing data from heterozygous bull carriers and control animals (45 animals in total). Six strong candidate causative mutations including polymorphisms previously reported in FANCI (Brachyspina), SLC35A3 (CVM), APAF1 (HH1) and three novel mutations with very damaging effect on the protein structure, according to SIFT and Polyphen-2, were detected in GART, SHBG and SLC37A2 genes. In conclusion, this study reveals a yet hidden consequence of the important inbreeding rate observed in intensively selected and specialized cattle breeds. Counter-selection of these mutations and management of matings will have positive consequences on female fertility in dairy cattle. PMID:23762392

  17. Developmental expression of Musashi-1 and Musashi-2 RNA-binding proteins during spermatogenesis: analysis of the deleterious effects of dysregulated expression.

    PubMed

    Sutherland, Jessie M; Fraser, Barbara A; Sobinoff, Alexander P; Pye, Victoria J; Davidson, Tara-Lynne; Siddall, Nicole A; Koopman, Peter; Hime, Gary R; McLaughlin, Eileen A

    2014-05-01

    Spermatogenesis is a complex developmental process whereby diploid spermatogenic stem cells become haploid and undergo a series of morphological changes to produce physically mature spermatozoa. Crucial to this process are a number of RNA-binding proteins, responsible for the posttranscriptional control of essential mRNAs and particularly pertinent to the two periods of inactive transcription that occur in spermatogenesis. One such group of RNA-binding proteins is the Musashi family, specifically Musashi-1 (MSI1) and Musashi-2 (MSI2), which act as key translational regulators in various stem cell populations and have been linked with the induction of tumorigenesis. In the present study, we examined the differential expression of mammalian MSI1 and MSI2 during germ cell development in the mouse testis. MSI1 was found to be predominately localized in mitotic gonocytes and spermatogonia, whereas MSI2 was detected in meiotic spermatocytes and differentiating spermatids. Extensive examination of the function of Musashi in spermatogenesis was achieved through the use of two transgenic mouse models with germ cell-specific overexpression of full-length isoforms of Msi1 or Msi2. These models demonstrated that aberrant expression of either Msi1 or Msi2 has deleterious effects on normal spermatogenesis, with Msi2 overexpression resulting in male sterility. Studies undertaken on human testicular seminoma tumors provide further insights into the relevance of MSI1 and MSI2 overexpression as diagnostic markers to human stem cell cancers. Overall this study provides further evidence for the unique functions that RNA-binding protein isoforms occupy within spermatogenesis, and introduces the potential manipulation of the Musashi family proteins to elucidate the mechanisms of posttranscriptional gene expression during germ cell development.

  18. Advanced materials for solid oxide fuel cells

    SciTech Connect

    Armstrong, T.R.; Stevenson, J.

    1995-08-01

    The purpose of this research is to improve the properties of the current state-of-the-art materials used for solid oxide fuel cells (SOFCs). The objectives are to: (1) develop materials based on modifications of the state-of-the-art materials; (2) minimize or eliminate stability problems in the cathode, anode, and interconnect; (3) Electrochemically evaluate (in reproducible and controlled laboratory tests) the current state-of-the-art air electrode materials and cathode/electrolyte interfacial properties; (4) Develop accelerated electrochemical test methods to evaluate the performance of SOFCs under controlled and reproducible conditions; and (5) Develop and test materials for use in low-temperature SOFCs. The goal is to modify and improve the current state-of-the-art materials and minimize the total number of cations in each material to avoid negative effects on the materials properties. Materials to reduce potential deleterious interactions, (3) improve thermal, electrical, and electrochemical properties, (4) develop methods to synthesize both state-of-the-art and alternative materials for the simultaneous fabricatoin and consolidation in air of the interconnections and electrodes with the solid electrolyte, and (5) understand electrochemical reactions at materials interfaces and the effects of component composition and processing on those reactions.

  19. Behavior of Materials Under Conditions of Thermal Stress

    NASA Technical Reports Server (NTRS)

    Manson, S S

    1954-01-01

    A review is presented of available information on the behavior of brittle and ductile materials under conditions of thermal stress and thermal shock. For brittle materials, a simple formula relating physical properties to thermal-shock resistance is derived and used to determine the relative significance of two indices currently in use for rating materials. For ductile materials, thermal-shock resistance depends upon the complex interrelation among several metallurgical variables which seriously affect strength and ductility. These variables are briefly discussed and illustrated from literature sources. The importance of simulating operating conditions in tests for rating materials is especially to be emphasized because of the importance of testing conditions in metallurgy. A number of practical methods that have been used to minimize the deleterious effects of thermal stress and thermal shock are outlined.

  20. Understanding Materials

    ERIC Educational Resources Information Center

    Katsioloudis, Petros J.

    2010-01-01

    Almost everything people have ever done has involved materials. Historical evidence indicates that "engineered materials" have been available and utilized for the benefit of humankind since the Neolithic period, beginning about 10,000 BC. Some of these materials have been in existence for thousands of years. At first, materials consisted of wood,…

  1. A fusion power plant without plasma-material interactions

    SciTech Connect

    Cohen, S.A.

    1997-04-01

    A steady-state fusion power plant is described which avoids the deleterious plasma-material interactions found in D-T fueled tokamaks. It is based on driven p-{sup 11}B fusion in a high-beta closed-field device, the field-reversed configuration (FRC), anchored in a gas-dynamic trap (GDT). The plasma outflow on the open magnetic-field lines is cooled by radiation in the GDT, then channeled through a magnetic nozzle, promoting 3-body recombination in the expansion region. The resulting supersonic neutral exhaust stream flows through a turbine, generating electricity.

  2. Containerless synthesis of ceramic materials using microwave heating

    NASA Technical Reports Server (NTRS)

    Dunn, B.; Crouch-Baker, S.

    1990-01-01

    It was demonstrated that microwave heating technique may be employed for the synthesis of a number of multicomponent ceramic oxide-based materials, e.g., YBa2Cu3O7 and CuFe2O4. A characteristic, and potentially extremely useful, feature of such synthesis is that they occur in significantly less time than that required using conventional furnace-based techniques. However, the information obtained to date is necessarily rather empirical, and systematic investigations of the use of microwave heating for the synthesis of ceramic materials are required. The synthesis of ceramic materials at high temperatures are often affected by unwanted, deleterious reactions of the reactants and/or products with the reaction container. Consequently, it is of interest to investigate the high temperature synthesis of ceramic materials using microwave heating in a containerless environment.

  3. Establishment and characterization of a penile cancer cell line, penl1, with a deleterious TP53 mutation as a paradigm of HPV-negative penile carcinogenesis

    PubMed Central

    Li, Zaishang; Deng, Chuangzhong; Wang, Liangjiao; Yu, Xingsu; Liang, Peili; Xie, Qiankun; Chen, Peng; Qin, Zike; Ye, Yunlin; Liu, Zhuowei; Zhou, Fangjian; Zhang, Zhenfeng; Han, Hui

    2016-01-01

    Purpose To establish penile cancer (PeCa) cell lines for the study of molecular mechanisms of carcinogenesis and testing therapeutic reagents. Materials and Methods We successfully established two PeCa cell lines from fresh tumor tissues from 21 cases. One cell line named Penl1 was isolated from a lymph node metastasis (LNM) of penile squamous cell carcinoma (PeSCC), usual type and comprehensively characterized here. Our in-depth characterization analysis of the Penl1 cell line included morphology, tumorigenicity, genetic characteristics, protein expression, biology, and chemosensitivity. Penl1 was authenticated by single tandem repeat (STR) DNA typing. Results Comparative histomorphology, genetic characteristics, and protein expression patterns revealed essential similarities between the cell line and its corresponding LNM. In-depth characterization analysis of Penl1 cell line revealed tumorigenicity in immunodeficient mice, negative human papilloma virus (HPV) and mycoplasma infection, TP53 mutations and sensitivity to cisplatin and epirubicin. STR DNA typing did not match any cell lines within three international cell banks. The limitation of this study is that one patient cannot represent the complete heterogeneity of PeCa, especially primary tumor. Conclusions We established and characterized an HPV-negative and moderately differentiated PeCa cell model with a TP53 missense mutation from a PeSCC, usual type patient. A preliminarily study of carcinogenesis and chemosensitivity suggests that this cell model carries a tumor suppressor gene mutation and is sensitive to chemotherapy drugs. PMID:27351128

  4. Analytic materials

    NASA Astrophysics Data System (ADS)

    Milton, Graeme W.

    2016-11-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90° rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  5. Contrast Materials

    MedlinePlus

    ... veins of the body, including vessels in the brain, neck, chest, abdomen, pelvis and legs soft tissues of the body, including the muscles, fat and skin brain breast Microbubble Contrast Materials Microbubble contrast materials are ...

  6. Analytic materials.

    PubMed

    Milton, Graeme W

    2016-11-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90(°) rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  7. Extensive recombination-induced disruption of genetic interactions is highly deleterious but can be partially reversed by small numbers of secondary recombination events.

    PubMed

    Monjane, Adérito L; Martin, Darren P; Lakay, Francisco; Muhire, Brejnev M; Pande, Daniel; Varsani, Arvind; Harkins, Gordon; Shepherd, Dionne N; Rybicki, Edward P

    2014-07-01

    Although homologous recombination can potentially provide viruses with vastly more evolutionary options than are available through mutation alone, there are considerable limits on the adaptive potential of this important evolutionary process. Primary among these is the disruption of favorable coevolved genetic interactions that can occur following the transfer of foreign genetic material into a genome. Although the fitness costs of such disruptions can be severe, in some cases they can be rapidly recouped by either compensatory mutations or secondary recombination events. Here, we used a maize streak virus (MSV) experimental model to explore both the extremes of recombination-induced genetic disruption and the capacity of secondary recombination to adaptively reverse almost lethal recombination events. Starting with two naturally occurring parental viruses, we synthesized two of the most extreme conceivable MSV chimeras, each effectively carrying 182 recombination breakpoints and containing thorough reciprocal mixtures of parental polymorphisms. Although both chimeras were severely defective and apparently noninfectious, neither had individual movement-, encapsidation-, or replication-associated genome regions that were on their own "lethally recombinant." Surprisingly, mixed inoculations of the chimeras yielded symptomatic infections with viruses with secondary recombination events. These recombinants had only 2 to 6 breakpoints, had predominantly inherited the least defective of the chimeric parental genome fragments, and were obviously far more fit than their synthetic parents. It is clearly evident, therefore, that even when recombinationally disrupted virus genomes have extremely low fitness and there are no easily accessible routes to full recovery, small numbers of secondary recombination events can still yield tremendous fitness gains. Importance: Recombination between viruses can generate strains with enhanced pathological properties but also runs the risk

  8. Nanostructured materials

    NASA Astrophysics Data System (ADS)

    Moriarty, Philip

    2001-03-01

    Nanostructured materials may be defined as those materials whose structural elements - clusters, crystallites or molecules - have dimensions in the 1 to 100 nm range. The explosion in both academic and industrial interest in these materials over the past decade arises from the remarkable variations in fundamental electrical, optical and magnetic properties that occur as one progresses from an `infinitely extended' solid to a particle of material consisting of a countable number of atoms. This review details recent advances in the synthesis and investigation of functional nanostructured materials, focusing on the novel size-dependent physics and chemistry that results when electrons are confined within nanoscale semiconductor and metal clusters and colloids. Carbon-based nanomaterials and nanostructures including fullerenes and nanotubes play an increasingly pervasive role in nanoscale science and technology and are thus described in some depth. Current nanodevice fabrication methods and the future prospects for nanostructured materials and nanodevices are discussed.

  9. Scintillator material

    DOEpatents

    Anderson, D.F.; Kross, B.J.

    1992-07-28

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography. 4 figs.

  10. Scintillator material

    DOEpatents

    Anderson, David F.; Kross, Brian J.

    1994-01-01

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography.

  11. Scintillator material

    DOEpatents

    Anderson, David F.; Kross, Brian J.

    1992-01-01

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography.

  12. Scintillator material

    DOEpatents

    Anderson, D.F.; Kross, B.J.

    1994-06-07

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography. 4 figs.

  13. Compatibility of refrigerants and lubricants with motor materials. Volume 1, Final report

    SciTech Connect

    Doerr, R.; Kujak, S.

    1993-05-01

    This volume contains the abstract, scope, discussion of results, charts of motor material compatibility, test procedures, material identifications, and 84 pages of data summary tables. Compatibility test results for 11 pure refrigerants and 17 refrigerant-lubricant combinations with 24 motor materials are included. The greatest effect on the motor materials was caused by adsorption followed by desorption of refrigerants at higher temperatures. High internal pressure of the adsorbed refrigerants and their tendency to evolve from the materials resulted in blisters, cracks, internal bubbles in the varnish, and delamination or bubbles in the sheet insulations. The second effect was extraction or dissolution of materials that lead to embrittlement of some sheet insulations. HCFC-22 and HCFC- 22/mineral oil had the most deleterious effects; the materials are expected to be reliable when used with most of the new refrigerants and lubricants. Tables.

  14. Nano Materials

    DTIC Science & Technology

    2007-03-01

    Nano Materials Henne van Heeren enablingMNT Drakensteynlaan 34 3319 RG Dordrecht The Netherlands Henne@enablingMNT.com Introduction... micro sized particles. Nanotubes From a Mancef patent investigation it was learned that carbon nanotechnology (mainly nanotubes, but also...for high purity nanotubes. RTO-EN-AVT-129bis 3 - 1 van Heeren, H. (2007) Nano Materials. In Nanotechnology Aerospace Applications

  15. Materials Repurposed

    ERIC Educational Resources Information Center

    White, Orvil L.; Townsend, J. Scott

    2008-01-01

    Few teachers find themselves with the support to purchase all of the materials they ideally need to supply their classrooms. Buying one or two simple, ready-made items can put a serious strain on anyone's budget. However, materials for science in the classroom need not be prefabricated or expensive. By looking at the function and purpose of any…

  16. Bioresponsive materials

    NASA Astrophysics Data System (ADS)

    Lu, Yue; Aimetti, Alex A.; Langer, Robert; Gu, Zhen

    2016-10-01

    'Smart' bioresponsive materials that are sensitive to biological signals or to pathological abnormalities, and interact with or are actuated by them, are appealing therapeutic platforms for the development of next-generation precision medications. Armed with a better understanding of various biologically responsive mechanisms, researchers have made innovations in the areas of materials chemistry, biomolecular engineering, pharmaceutical science, and micro- and nanofabrication to develop bioresponsive materials for a range of applications, including controlled drug delivery, diagnostics, tissue engineering and biomedical devices. This Review highlights recent advances in the design of smart materials capable of responding to the physiological environment, to biomarkers and to biological particulates. Key design principles, challenges and future directions, including clinical translation, of bioresponsive materials are also discussed.

  17. Composite material

    DOEpatents

    Hutchens, Stacy A [Knoxville, TN; Woodward, Jonathan [Solihull, GB; Evans, Barbara R [Oak Ridge, TN; O'Neill, Hugh M [Knoxville, TN

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  18. Periodontal materials.

    PubMed

    Darby, I

    2011-06-01

    Periodontics is more associated with debridement of periodontal pockets and not generally thought of as using dental materials in the treatment of patients. However, the last 30 years have seen the development of materials used in regeneration of the periodontal tissues following periodontal disease, guided tissue regeneration, and the use of these materials in bone regeneration more recently, guided bone regeneration. The materials used include bone grafts and membranes, but also growth factors and cells-based therapies. This review provides an overview of the materials currently used and looks at contemporary research with a view to what may be used in the future. It also looks at the clinical effectiveness of these regenerative therapies with an emphasis on what is available in Australia.

  19. Insulation Material

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Manufactured by Hitco Materials Division of Armco, Inc. a ceramic fiber insulation material known as Refrasil has been used extensively as a heat-absorbing ablative reinforcement for such space systems as rocket motor nozzles, combustion chambers, and re-entry shields. Refrasil fibers are highly porous and do not melt or vaporize until fibers exceed 3,100 degrees Fahrenheit. Due to these and other properties, Refrasil has found utility in a number of industrial high temperature applications where glass, asbestos and other materials fail. Hitco used this insulation to assist Richardson Co., Inc. in the manufacturing of hard rubber and plastic molded battery cases.

  20. Complex Materials

    ScienceCinema

    Cooper, Valentino

    2016-07-12

    Valentino Cooper uses some of the world's most powerful computing to understand how materials work at subatomic levels, studying breakthroughs such as piezoelectrics, which convert mechanical stress to electrical energy.

  1. Contrast Materials

    MedlinePlus

    ... or other medical conditions history of asthma and hay fever history of heart disease, diabetes, kidney disease, thyroid ... materials if: you have a history of asthma, hay fever, or other allergies, which will increase your risk ...

  2. Hazardous materials

    MedlinePlus

    ... for words like: Acid Alkali Carcinogenic Caution Corrosive Danger Explosive Flammable Irritant Radioactive Unstable Warning A label ... leak occurs What to do if there is danger from the material mixing with other substances How ...

  3. CURRICULUM MATERIALS.

    ERIC Educational Resources Information Center

    New Jersey State Dept. of Education, Trenton.

    MATERIALS ARE LISTED BY 36 TOPICS ARRANGED IN ALPHABETICAL ORDER. TOPICS INCLUDE APPRENTICE TRAINING, BAKING, DRAFTING, ENGLISH, GLASSBLOWING, HOME ECONOMICS, INDUSTRIAL CHEMISTRY, MACHINE SHOP, NEEDLE TRADES, REFRIGERATION, AND UPHOLSTERY. PRICES ARE GIVEN FOR EACH ITEM. (EL)

  4. Propulsion materials

    SciTech Connect

    Wall, Edward J.; Sullivan, Rogelio A.; Gibbs, Jerry L.

    2008-01-01

    The Department of Energy’s (DOE’s) Office of Vehicle Technologies (OVT) is pleased to introduce the FY 2007 Annual Progress Report for the Propulsion Materials Research and Development Program. Together with DOE national laboratories and in partnership with private industry and universities across the United States, the program continues to engage in research and development (R&D) that provides enabling materials technology for fuel-efficient and environmentally friendly commercial and passenger vehicles.

  5. Rice PROTEIN l-ISOASPARTYL METHYLTRANSFERASE isoforms differentially accumulate during seed maturation to restrict deleterious isoAsp and reactive oxygen species accumulation and are implicated in seed vigor and longevity.

    PubMed

    Petla, Bhanu Prakash; Kamble, Nitin Uttam; Kumar, Meenu; Verma, Pooja; Ghosh, Shraboni; Singh, Ajeet; Rao, Venkateswara; Salvi, Prafull; Kaur, Harmeet; Saxena, Saurabh Chandra; Majee, Manoj

    2016-07-01

    PROTEIN l-ISOASPARTYL O-METHYLTRANSFERASE (PIMT) is a protein-repairing enzyme involved in seed vigor and longevity. However, the regulation of PIMT isoforms during seed development and the mechanism of PIMT-mediated improvement of seed vigor and longevity are largely unknown. In this study in rice (Oryza sativa), we demonstrate the dynamics and correlation of isoaspartyl (isoAsp)-repairing demands and PIMT activity, and their implications, during seed development, germination and aging, through biochemical, molecular and genetic studies. Molecular and biochemical analyses revealed that rice possesses various biochemically active and inactive PIMT isoforms. Transcript and western blot analyses clearly showed the seed development stage and tissue-specific accumulation of active isoforms. Immunolocalization studies revealed distinct isoform expression in embryo and aleurone layers. Further analyses of transgenic lines for each OsPIMT isoform revealed a clear role in the restriction of deleterious isoAsp and age-induced reactive oxygen species (ROS) accumulation to improve seed vigor and longevity. Collectively, our data suggest that a PIMT-mediated, protein repair mechanism is initiated during seed development in rice, with each isoform playing a distinct, yet coordinated, role. Our results also raise the intriguing possibility that PIMT repairs antioxidative enzymes and proteins which restrict ROS accumulation, lipid peroxidation, etc. in seed, particularly during aging, thus contributing to seed vigor and longevity.

  6. Parachute materials

    SciTech Connect

    Peterson, C.W.; Johnson, D.W.

    1987-06-01

    The purpose of this paper is to present guidelines for the use of Kevlar and nylon materials in modern parachute systems. Nylon has been used in parachutes for many years, so this discussion will place emphasis upon Kevlar material properties and their application to parachute design and construction. Kevlar-29 is an aramid fiber manufactured by DuPont and is being used on parachute systems requiring high strength-to-weight ratios or sustained strength at high temperatures. Tests of parachutes using Kevlar webbing, braided cords, ribbons, and thread have demonstrated that these Kevlar materials can be used successfully in ribbon parachutes with no detrimental effects on performance. A few changes must be made in the design of a ribbon parachute to accommodate Kevlar's high modulus. Examples of parachutes that use Kevlar suspension lines, radials, ribbons, reefing lines, bridles, and skirt bands are presented to show that they are much lighter and more resistant to aerodynamic heating than all-nylon parachutes. Nylon continues to be an important material for high-performance parachute systems, however. New nylon weaves have resulted in lighter weight, stronger ribbon materials with excellent sewability characteristics.

  7. Packaging Materials and Design for Improved PV Module Reliability

    SciTech Connect

    Jorgensen, G.; Terwilliger, K.; Kempe, M.; Pern, J.; Glick, S.; del Cueto, J.; Kennedy, C.; McMahon, T.

    2005-01-01

    A number of candidate alternative encapsulant and soft backsheet materials have been evaluated in terms of their suitability for photovoltaic (PV) module packaging applications. Relevant properties, including peel strength as a function of damp heat exposure and permeability, have been measured. Based on these tests, promising new encapsulants with adhesion-promoting primers have been identified that result in improved properties. Test results for backsheets provided by industry and prepared at the National Renewable Energy Laboratory (NREL) have suggested strategies to achieve significantly improved products. The ability of glass/glass and glass/breathable backsheet constructions laminated with various encapsulant and/or edge seal materials to protect thin-film aluminum coatings deposited onto glass substrates was assessed. Glass/glass laminate constructions can trap harmful compounds that catalyze moisture-driven corrosion of the aluminum. Constructions with breathable backsheets allow higher rates of moisture ingress, but also allow egress of deleterious substances that can result in decreased corrosion.

  8. Projections on structures and material strength in the computational context

    NASA Technical Reports Server (NTRS)

    Knauss, Wolfgang G.

    1993-01-01

    The ideas associated with the subsequent viewgraphs are summarized. The primary motivation behind this presentation is to observe that certain macroscopic, microscopic, and submicroscopic phenomena are being understood that have basic influence on understanding the durability and high temperature sensitivity of polymers and polymer-based composites. This understanding covers important issues of long term stability with respect to residual stresses and deformations which can have very deleterious effects on structures used for long periods of time as a result of the heat-involving manufacturing process. Beyond this, important progress is being made in understanding the nonlinear material response of polymers in the fracture context, because the nonlinear mechanics of the material at the tip of a crack, either propagating or ready to do so, is being understood with increasing precision.

  9. Hardfacing material

    DOEpatents

    Branagan, Daniel J [Iona, ID

    2012-01-17

    A method of producing a hard metallic material by forming a mixture containing at least 55% iron and at least one of boron, carbon, silicon and phosphorus. The mixture is formed into an alloy and cooled to form a metallic material having a hardness of greater than about 9.2 GPa. The invention includes a method of forming a wire by combining a metal strip and a powder. The metal strip and the powder are rolled to form a wire containing at least 55% iron and from two to seven additional elements including at least one of C, Si and B. The invention also includes a method of forming a hardened surface on a substrate by processing a solid mass to form a powder, applying the powder to a surface to form a layer containing metallic glass, and converting the glass to a crystalline material having a nanocrystalline grain size.

  10. THERMOELECTRIC MATERIALS

    DTIC Science & Technology

    Preparation of materials: Multiple oxides: Additions of TiO2, ZrO2 , CeO2 and SnO2 to YCrO3 were prepared. X-ray diffrac ion data established the...La2O3 and Nb2O5 to CeO2; CdO, Bi2O3, Sb2O5, MoO3 and WO3 to PbNb2O6 or Pb2N6207. Percentage compositions and ceramic properties of the materials are

  11. Squishy Materials

    NASA Astrophysics Data System (ADS)

    Habdas, Piotr; Weeks, Eric R.; Lynn, David G.

    2006-05-01

    Most people do not realize that many substances they use in the kitchen and the bathroom are not simple liquids or solids. Everyone is familiar with three states of matter: solids, liquids, and gases. However, creams, shampoo, toothpaste, and ketchup all have properties of both liquids and solids. This paper describes demonstrations and laboratory exercises1 that show intriguing properties of squishy substances, defined as materials that are not unambiguously solid, liquid, or gas. Unlike some areas of physics, the concepts behind squishy materials are understandable even by beginning students. Squishy physics can be used to show physics questions arising from everyday life and to convey the excitement of current research.

  12. Audiovisual Materials.

    ERIC Educational Resources Information Center

    American Council on Education, Washington, DC. HEATH/Closer Look Resource Center.

    The fact sheet presents a suggested evaluation framework for use in previewing audiovisual materials, a list of selected resources, and an annotated list of films which were shown at the AHSSPPE '83 Media Fair as part of the national conference of the Association on Handicapped Student Service Programs in Postsecondary Education. Evaluation…

  13. BIOBASED MATERIALS

    EPA Science Inventory

    Biobased materials refer to products that mainly consist of a substance (or substances) derived from living matter (biomass) and either occur naturally or are synthesized, or it may refer to products made by processes that use biomass. Following a strict definition, many common m...

  14. Strategic Materials

    DTIC Science & Technology

    2007-01-01

    to meet their obligations. Competition requires maintaining a lean cost structure, managing raw material requirements, improving the quality of products and...competitive reputations in the market through the quality of products and the ability to meet defense ballistic performance specifications and delivery

  15. Superconducting Materials

    NASA Technical Reports Server (NTRS)

    1995-01-01

    After working with Lewis Research Center and Jet Propulsion Laboratory, Superconducting Technologies, Inc. (STI) adapted NASA requirements and refined its own standard production recipe. STI uses high temperature superconducting (HTS) materials in its basic products: high quality thin films, circuits and components. Applications include microwave circuits for radar to reduce interference.

  16. Materials Science

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Materials Science Program is structured so that NASA s headquarters is responsible for the program content and selection, through the Enterprise Scientist, and MSFC provides for implementation of ground and flight programs with a Discipline Scientist and Discipline Manager. The Discipline Working Group of eminent scientists from outside of NASA acts in an advisory capacity and writes the Discipline Document from which the NRA content is derived. The program is reviewed approximately every three years by groups such as the Committee on Microgravity Research, the National Materials Advisory Board, and the OBPR Maximization and Prioritization (ReMaP) Task Force. The flight program has had as many as twenty-six principal investigators (PIs) in flight or flight definition stage, with the numbers of PIs in the future dependent on the results of the ReMaP Task Force and internal reviews. Each project has a NASA-appointed Project Scientist, considered a half-time job, who assists the PI in understanding and preparing for internal reviews such as the Science Concept Review and Requirements Definition Review. The Project Scientist also insures that the PI gets the maximum science support from MSFC, represents the PI to the MSFC community, and collaborates with the Project Manager to insure the project is well-supported and remains vital. Currently available flight equipment includes the Materials Science Research Rack (MSRR-1) and Microgravity Science Glovebox. Ground based projects fall into one or more of several categories. Intellectual Underpinning of Flight Program projects include theoretical studies backed by modeling and computer simulations; bring to maturity new research, often by young researchers, and may include preliminary short duration low gravity experiments in the KC-135 aircraft or drop tube; enable characterization of data sets from previous flights; and provide thermophysical property determinations to aid PIs. Radiation Shielding and preliminary In

  17. Strategic Materials

    DTIC Science & Technology

    2001-01-01

    temperature superconductors may one day open the door to magnetic levitation vehicles. And, medical technology is expected to increase the use of...telemedicine, telemaintenance, new internet-based music formats and unified messaging will demand the additional bandwidth that only fiber optic cables...controllers that create new functionality, such as vibration control and health monitoring. One approach used to develop smart materials is to “create

  18. Magnetic Materials

    DTIC Science & Technology

    1985-03-01

    Defense supported the development of microwave ferrites , and today 85 percent of that market is still military. Magnetostrictive sensors for sonar...or hard ferrite , Although both cobalt and samarium are expensive and the production process is difficult v4,*-°’. because of the strong tendency of...plentiful materials supply and low magnet cost. This calls for automated mass-production methods for ferrites and, perhaps, Nd-Fe-based REPMs. But for

  19. Ceramic Material.

    DTIC Science & Technology

    1990-05-02

    A ceramic material which is (1) ceramics based on monoclinic BaO.Al2O3.2SiO2; (2) ceramics based on monoclinic SrO.Al2O3.2SiO2; or (3) ceramics based on monoclinic solid solution of BaO.Al2O3.2SiO2 and SrO.Al2O3.2SiO2.

  20. Prosthesis Material

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In this photograph, James Carden uses a NASA-developed prosthesis to moved planks around his home. Derived from foam insulation technology used to protect the Space Shuttle External Tank from excessive heat, FAB/CAD, a subsidiary of the Harshberger Prosthetic and Orthotic Center, utilized the technology to replace the heavy, fragile plaster they used to produce master molds for prosthetics. The new material was lighter, cheaper and easier to manufacture than plaster, resulting in lower costs to the customer.

  1. Prosthesis Material

    NASA Technical Reports Server (NTRS)

    2004-01-01

    In this photograph, Amputee Amie Bradly uses a NASA-developed prosthesis to paint her fingernails. Derived from foam insulation technology used to protect the Space Shuttle External Tank from excessive heat, FAB/CAD, a subsidiary of the Harshberger Prosthetic and Orthotic Center, utilized the technology to replace the heavy, fragile plaster they used to produce master molds for prosthetics. The new material was lighter, cheaper and easier to manufacture than plaster, resulting in lower costs to the customer.

  2. Prosthesis Material

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In this photograph, Sandra Rossi user her NASA-developed prosthesis for the first time. Derived from foam insulation technology used to protect the Space Shuttle External Tank from excessive heat, FAB/CAD, a subsidiary of the Harshberger Prosthetic and Orthotic Center, utilized the technology to replace the heavy, fragile plaster they used to produce master molds for prosthetics. The new material was lighter, cheaper and easier to manufacture than plaster, resulting in lower costs to the customer.

  3. Strategic Materials

    DTIC Science & Technology

    2006-01-01

    Sears, US Navy Lt Col Mark Williams, US Air Force Dr. Sylvia Babus , Faculty Dr. Maureen Crandall, Faculty Mr. Bill Jones, Faculty Strategic...graying rapidly, populated predominantly with baby- boomers over 40 years of age. Aggravating this demographic shift, the number of workforce S&E...Transnational Environment. [Student Essay from Strategic Materials Industry Study 2005, available from Dr. Sylvia Babus , Industrial College of the Armed

  4. Fullerene materials

    SciTech Connect

    Malhotra, R.; Ruoff, R.S.; Lorents, D.C.

    1995-04-01

    Fullerenes are all-carbon cage molecules. The most celebrated fullerene is the soccer-ball shaped C{sub 60}, which is composed of twenty hexagons and twelve pentagons. Because its structure is reminiscent of the geodesic domes of architect R. Buckminster Fuller, C{sub 60} is called buckminsterfullerene, and all the materials in the family are designated fullerenes. Huffman and Kraetschmer`s discovery unleashed activity around the world as scientists explored production methods, properties, and potential uses of fullerenes. Within a short period, methods for their production in electric arcs, plasmas, and flames were discovered, and several companies began selling fullerenes to the research market. What is remarkable is that in all these methods, carbon atoms assemble themselves into cage structures. The capability for self-assembly points to some inherent stability of these structures that allows their formation. The unusual structure naturally leads to unusual properties. Among them are ready solubility in solvents and a relatively high vapor pressure for a pure carbon material. The young fullerene field has already produced a surprising array of structures for the development of carbon-base materials having completely new and different properties from any that were previously possible.

  5. Alloy materials

    DOEpatents

    Hans Thieme, Cornelis Leo; Thompson, Elliott D.; Fritzemeier, Leslie G.; Cameron, Robert D.; Siegal, Edward J.

    2002-01-01

    An alloy that contains at least two metals and can be used as a substrate for a superconductor is disclosed. The alloy can contain an oxide former. The alloy can have a biaxial or cube texture. The substrate can be used in a multilayer superconductor, which can further include one or more buffer layers disposed between the substrate and the superconductor material. The alloys can be made a by process that involves first rolling the alloy then annealing the alloy. A relatively large volume percentage of the alloy can be formed of grains having a biaxial or cube texture.

  6. Construction material

    DOEpatents

    Wagh, Arun S.; Antink, Allison L.

    2008-07-22

    A structural material of a polystyrene base and the reaction product of the polystyrene base and a solid phosphate ceramic is applied as a slurry which includes one or more of a metal oxide or a metal hydroxide with a source of phosphate to produce a phosphate ceramic and a poly (acrylic acid or acrylate) or combinations or salts thereof and polystyrene or MgO applied to the polystyrene base and allowed to cure so that the dried aqueous slurry chemically bonds to the polystyrene base. A method is also disclosed of applying the slurry to the polystyrene base.

  7. Casting materials

    DOEpatents

    Chaudhry, Anil R.; Dzugan, Robert; Harrington, Richard M.; Neece, Faurice D.; Singh, Nipendra P.

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  8. Method of mitigating titanium impurities effects in p-type silicon material for solar cells

    NASA Technical Reports Server (NTRS)

    Salama, A. M. (Inventor)

    1980-01-01

    Microstructural evaluation tests performed on Cu-doped, Ti-doped and Cu/Ti doped p-type silicon single crystal wafers, before and after the solar cell fabrication, and evaluation of both dark forward and reverse I-V characteristic records for the solar cells produced from the corresponding silicon wafers, show that Cu mitigates the unfavorable effects of Ti, and thus provides for higher conversion efficiency, thereby providing an economical way to reduce the deleterious effects of titanium, one of the impurities present in metallurgical grade silicon material.

  9. Materializing superghosts

    NASA Astrophysics Data System (ADS)

    Alexandrov, V.; Krotov, D.; Losev, A.; Lysov, V.

    2007-12-01

    The off-shell Batalin-Vilkovysky (BV) realization has been constructed for N = 1, d = 10 super-Yang-Mills theory with seven auxiliary fields. This becomes possible due to the materialized ghost phenomenon. Namely, supersymmetry ghosts are coordinates on a manifold B of ten-dimensional spinors with the pure spinors cut out. Auxiliary fields are sections of a bundle over B, and supersymmetry transformations are nonlinear in ghosts. By integrating out the auxiliary fields, we obtain an on-shell supersymmetric BV action with quadratic terms in the antifields. Exactly this on-shell BV action was obtained in our previous paper after integration out of auxiliary fields in the framework of a pure spinor superfield formalism.

  10. Photovoltaic Materials

    SciTech Connect

    Duty, C.; Angelini, J.; Armstrong, B.; Bennett, C.; Evans, B.; Jellison, G. E.; Joshi, P.; List, F.; Paranthaman, P.; Parish, C.; Wereszczak, A.

    2012-10-15

    The goal of the current project was to help make the US solar industry a world leader in the manufacture of thin film photovoltaics. The overall approach was to leverage ORNL’s unique characterization and processing technologies to gain a better understanding of the fundamental challenges for solar cell processing and apply that knowledge to targeted projects with industry members. ORNL has the capabilities in place and the expertise required to understand how basic material properties including defects, impurities, and grain boundaries affect the solar cell performance. ORNL also has unique processing capabilities to optimize the manufacturing process for fabrication of high efficiency and low cost solar cells. ORNL recently established the Center for Advanced Thin-film Systems (CATS), which contains a suite of optical and electrical characterization equipment specifically focused on solar cell research. Under this project, ORNL made these facilities available to industrial partners who were interested in pursuing collaborative research toward the improvement of their product or manufacturing process. Four specific projects were pursued with industrial partners: Global Solar Energy is a solar industry leader in full scale production manufacturing highly-efficient Copper Indium Gallium diSelenide (CIGS) thin film solar material, cells and products. ORNL worked with GSE to develop a scalable, non-vacuum, solution technique to deposit amorphous or nanocrystalline conducting barrier layers on untextured stainless steel substrates for fabricating high efficiency flexible CIGS PV. Ferro Corporation’s Electronic, Color and Glass Materials (“ECGM”) business unit is currently the world’s largest supplier of metallic contact materials in the crystalline solar cell marketplace. Ferro’s ECGM business unit has been the world's leading supplier of thick film metal pastes to the crystalline silicon PV industry for more than 30 years, and has had operational cells and

  11. MATERIAL PROCESSING FOR SELF-ASSEMBLING MACHINE SYSTEMS

    SciTech Connect

    K. LACKNER; D. BUTT; C. WENDT

    1999-06-01

    We are developing an important aspect of a new technology based on self-reproducing machine systems. Such systems could overcome resource limitations and control the deleterious side effects of human activities on the environment. Machine systems capable of building themselves promise an increase in industrial productivity as dramatic as that of the industrial revolution. To operate successfully, such systems must procure necessary raw materials from their surroundings. Therefore, next to automation, most critical for this new technology is the ability to extract important chemicals from readily available soils. In contrast to conventional metallurgical practice, these extraction processes cannot make substantial use of rare elements. We have designed a thermodynamically viable process and experimentally demonstrated most steps that differ from common practice. To this end we had to develop a small, disposable vacuum furnace system. Our work points to a viable extraction process.

  12. PREFACE: Superconducting materials Superconducting materials

    NASA Astrophysics Data System (ADS)

    Charfi Kaddour, Samia; Singleton, John; Haddad, Sonia

    2011-11-01

    The discovery of superconductivity in 1911 was a great milestone in condensed matter physics. This discovery has resulted in an enormous amount of research activity. Collaboration among chemists and physicists, as well as experimentalists and theoreticians has given rise to very rich physics with significant potential applications ranging from electric power transmission to quantum information. Several superconducting materials have been synthesized. Crucial progress was made in 1987 with the discovery of high temperature superconductivity in copper-based compounds (cuprates) which have revealed new fascinating properties. Innovative theoretical tools have been developed to understand the striking features of cuprates which have remained for three decades the 'blue-eyed boy' for researchers in superconductor physics. The history of superconducting materials has been notably marked by the discovery of other compounds, particularly organic superconductors which despite their low critical temperature continue to attract great interest regarding their exotic properties. Last but not least, the recent observation of superconductivity in iron-based materials (pnictides) has renewed hope in reaching room temperature superconductivity. However, despite intense worldwide studies, several features related to this phenomenon remain unveiled. One of the fundamental key questions is the mechanism by which superconductivity takes place. Superconductors continue to hide their 'secret garden'. The new trends in the physics of superconductivity have been one of the two basic topics of the International Conference on Conducting Materials (ICoCoM2010) held in Sousse,Tunisia on 3-7 November 2010 and organized by the Tunisian Physical Society. The conference was a nice opportunity to bring together participants from multidisciplinary domains in the physics of superconductivity. This special section contains papers submitted by participants who gave an oral contribution at ICoCoM2010

  13. Biointegrating Materials

    NASA Astrophysics Data System (ADS)

    Amédée, J.; Bordenave, L.; Durrieu, M.-C.; Fricain, J.-C.; Pothuaud, L.

    The extraordinary increase in human longevity explains the growing need for replacement organs. The remarkable successes of conventional transplants (associated with the development of effective antirejection drugs and improved control of their administration) are also accompanied by certain drawbacks. First on the list is an inadequate supply of replacement organs: the number of candidates for transplants grows larger, opposition to the removal of organs increases, and the number of transplants has reached a ceiling. Furthermore, it has come to light over the past few years that organ transplants carry a significant risk of transmitting pathogens. Finally, the main drawback lies in the need to pursue an immunosuppression treatment. Scientists and doctors have long been in search of alternatives to human organ transplants. According to the definition drawn up in Chester in 1986 at the Consensus Conference organised under the aegis of the European Society for Biomaterials, biomaterials are non-viable materials used in a medical device and destined to interact with biological systems, whether they contribute to the constitution of a diagnostic device, a tissue or organ substitute, or a device designed to provide functional assistance or replacement.

  14. Critical Materials Institute

    ScienceCinema

    Alex King

    2016-07-12

    Ames Laboratory Director Alex King talks about the goals of the Critical Materials Institute in diversifying the supply of critical materials, developing substitute materials, developing tools and techniques for recycling critical materials, and forecasting materials needs to avoid future shortages.

  15. Critical Materials Institute

    SciTech Connect

    Alex King

    2013-01-09

    Ames Laboratory Director Alex King talks about the goals of the Critical Materials Institute in diversifying the supply of critical materials, developing substitute materials, developing tools and techniques for recycling critical materials, and forecasting materials needs to avoid future shortages.

  16. Functional Hydrogel Materials Inspired by Amyloid

    NASA Astrophysics Data System (ADS)

    Schneider, Joel

    2012-02-01

    Protein assembly resulting in the formation of amyloid fibrils, assemblies rich in cross beta-sheet structure, is normally thought of as a deleterious event associated with disease. However, amyloid formation is also involved in a diverse array of normal biological functions such as cell adhesion, melanin synthesis, insect defense mechanism and modulation of water surface tension by fungi and bacteria. These findings indicate that Nature has evolved to take advantage of large, proteinaceous fibrillar assemblies to elicit function. We are designing functional materials, namely hydrogels, from peptides that self-assembled into fibrillar networks, rich in cross beta-sheet structure. These gels can be used for the direct encapsulation and delivery of small molecule-, protein- and cell-based therapeutics. Loaded gels exhibit shear-thinning/self-healing mechanical properties enabling their delivery via syringe. In addition to their use for delivery, we have found that some of these gels display antibacterial activity. Although cytocompatible towards mammalian cells, the hydrogels can kill a broad spectrum of bacteria on contact.

  17. Gas storage materials, including hydrogen storage materials

    DOEpatents

    Mohtadi, Rana F; Wicks, George G; Heung, Leung K; Nakamura, Kenji

    2014-11-25

    A material for the storage and release of gases comprises a plurality of hollow elements, each hollow element comprising a porous wall enclosing an interior cavity, the interior cavity including structures of a solid-state storage material. In particular examples, the storage material is a hydrogen storage material, such as a solid state hydride. An improved method for forming such materials includes the solution diffusion of a storage material solution through a porous wall of a hollow element into an interior cavity.

  18. Gas storage materials, including hydrogen storage materials

    DOEpatents

    Mohtadi, Rana F; Wicks, George G; Heung, Leung K; Nakamura, Kenji

    2013-02-19

    A material for the storage and release of gases comprises a plurality of hollow elements, each hollow element comprising a porous wall enclosing an interior cavity, the interior cavity including structures of a solid-state storage material. In particular examples, the storage material is a hydrogen storage material such as a solid state hydride. An improved method for forming such materials includes the solution diffusion of a storage material solution through a porous wall of a hollow element into an interior cavity.

  19. Geopolymer resin materials, geopolymer materials, and materials produced thereby

    SciTech Connect

    Seo, Dong-Kyun; Medpelli, Dinesh; Ladd, Danielle; Mesgar, Milad

    2016-03-29

    A product formed from a first material including a geopolymer resin material, a geopolymer resin, or a combination thereof by contacting the first material with a fluid and removing at least some of the fluid to yield a product. The first material may be formed by heating and/or aging an initial geopolymer resin material to yield the first material before contacting the first material with the fluid. In some cases, contacting the first material with the fluid breaks up or disintegrates the first material (e.g., in response to contact with the fluid and in the absence of external mechanical stress), thereby forming particles having an external dimension in a range between 1 nm and 2 cm.

  20. Materials Project: A Materials Genome Approach

    DOE Data Explorer

    Ceder, Gerbrand [MIT; Persson, Kristin [LBNL

    Technological innovation - faster computers, more efficient solar cells, more compact energy storage - is often enabled by materials advances. Yet, it takes an average of 18 years to move new materials discoveries from lab to market. This is largely because materials designers operate with very little information and must painstakingly tweak new materials in the lab. Computational materials science is now powerful enough that it can predict many properties of materials before those materials are ever synthesized in the lab. By scaling materials computations over supercomputing clusters, this project has computed some properties of over 80,000 materials and screened 25,000 of these for Li-ion batteries. The computations predicted several new battery materials which were made and tested in the lab and are now being patented. By computing properties of all known materials, the Materials Project aims to remove guesswork from materials design in a variety of applications. Experimental research can be targeted to the most promising compounds from computational data sets. Researchers will be able to data-mine scientific trends in materials properties. By providing materials researchers with the information they need to design better, the Materials Project aims to accelerate innovation in materials research.[copied from http://materialsproject.org/about] You will be asked to register to be granted free, full access.

  1. Composite material dosimeters

    DOEpatents

    Miller, Steven D.

    1996-01-01

    The present invention is a composite material containing a mix of dosimeter material powder and a polymer powder wherein the polymer is transparent to the photon emission of the dosimeter material powder. By mixing dosimeter material powder with polymer powder, less dosimeter material is needed compared to a monolithic dosimeter material chip. Interrogation is done with excitation by visible light.

  2. Method for forming materials

    DOEpatents

    Tolle, Charles R.; Clark, Denis E.; Smartt, Herschel B.; Miller, Karen S.

    2009-10-06

    A material-forming tool and a method for forming a material are described including a shank portion; a shoulder portion that releasably engages the shank portion; a pin that releasably engages the shoulder portion, wherein the pin defines a passageway; and a source of a material coupled in material flowing relation relative to the pin and wherein the material-forming tool is utilized in methodology that includes providing a first material; providing a second material, and placing the second material into contact with the first material; and locally plastically deforming the first material with the material-forming tool so as mix the first material and second material together to form a resulting material having characteristics different from the respective first and second materials.

  3. Flat-plate solar array project. Volume 2: Silicon material

    NASA Astrophysics Data System (ADS)

    Lutwack, R.

    1986-10-01

    The goal of the Silicon Material Task, a part of the Flat Plate Solar Array (FSA) Project, was to develop and demonstate the technology for the low cost production of silicon of suitable purity to be used as the basic material for the manufacture of terrestrial photovoltaic solar cells. Summarized are 11 different processes for the production of silicon that were investigated and developed to varying extent by industrial, university, and Government researchers. The silane production section of the Union Carbide Corp. (UCC) silane process was developed completely in this program. Coupled with Siemens-type chemical vapor deposition reactors, the process was carried through the pilot stage. The overall UCC process involves the conversion of metallurgical-grade silicon to silane followed by decomposition of the silane to purified silicon. The other process developments are described to varying extents. Studies are reported on the effects of impurities in silicon on both silicon-material properties and on solar cell performance. These studies on the effects of impurities yielded extensive information and models for relating specific elemental concentrations to levels of deleterious effects.

  4. Flat-plate solar array project. Volume 2: Silicon material

    NASA Technical Reports Server (NTRS)

    Lutwack, R.

    1986-01-01

    The goal of the Silicon Material Task, a part of the Flat Plate Solar Array (FSA) Project, was to develop and demonstate the technology for the low cost production of silicon of suitable purity to be used as the basic material for the manufacture of terrestrial photovoltaic solar cells. Summarized are 11 different processes for the production of silicon that were investigated and developed to varying extent by industrial, university, and Government researchers. The silane production section of the Union Carbide Corp. (UCC) silane process was developed completely in this program. Coupled with Siemens-type chemical vapor deposition reactors, the process was carried through the pilot stage. The overall UCC process involves the conversion of metallurgical-grade silicon to silane followed by decomposition of the silane to purified silicon. The other process developments are described to varying extents. Studies are reported on the effects of impurities in silicon on both silicon-material properties and on solar cell performance. These studies on the effects of impurities yielded extensive information and models for relating specific elemental concentrations to levels of deleterious effects.

  5. Transporting particulate material

    DOEpatents

    Aldred, Derek Leslie; Rader, Jeffrey A.; Saunders, Timothy W.

    2011-08-30

    A material transporting system comprises a material transporting apparatus (100) including a material transporting apparatus hopper structure (200, 202), which comprises at least one rotary transporting apparatus; a stationary hub structure (900) constraining and assisting the at least one rotary transporting apparatus; an outlet duct configuration (700) configured to permit material to exit therefrom and comprising at least one diverging portion (702, 702'); an outlet abutment configuration (800) configured to direct material to the outlet duct configuration; an outlet valve assembly from the material transporting system venting the material transporting system; and a moving wall configuration in the material transporting apparatus capable of assisting the material transporting apparatus in transporting material in the material transporting system. Material can be moved from the material transporting apparatus hopper structure to the outlet duct configuration through the at least one rotary transporting apparatus, the outlet abutment configuration, and the outlet valve assembly.

  6. Coated electroactive materials

    DOEpatents

    Amine, Khalil; Abouimrane, Ali

    2016-08-30

    A process includes suspending an electroactive material in a solvent, suspending or dissolving a carbon precursor in the solvent; and depositing the carbon precursor on the electroactive material to form a carbon-coated electroactive material. Compositions include a graphene-coated electroactive material prepared from a solution phase mixture or suspension of an electroactive material and graphene, graphene oxide, or a mixture thereof.

  7. Introductory Materials Laboratory.

    ERIC Educational Resources Information Center

    Ritter, John E., Jr.

    Described is an introductory materials science laboratory program which emphasizes crystal structure both on the atomistic and microscopic scale and the dependence of materials properties on structure. The content of this program is classified into four major areas: (1) materials science, (2) mechanical behavior of materials, (3) materials testing…

  8. Materials Informatics: Statistical Modeling in Material Science.

    PubMed

    Yosipof, Abraham; Shimanovich, Klimentiy; Senderowitz, Hanoch

    2016-12-01

    Material informatics is engaged with the application of informatic principles to materials science in order to assist in the discovery and development of new materials. Central to the field is the application of data mining techniques and in particular machine learning approaches, often referred to as Quantitative Structure Activity Relationship (QSAR) modeling, to derive predictive models for a variety of materials-related "activities". Such models can accelerate the development of new materials with favorable properties and provide insight into the factors governing these properties. Here we provide a comparison between medicinal chemistry/drug design and materials-related QSAR modeling and highlight the importance of developing new, materials-specific descriptors. We survey some of the most recent QSAR models developed in materials science with focus on energetic materials and on solar cells. Finally we present new examples of material-informatic analyses of solar cells libraries produced from metal oxides using combinatorial material synthesis. Different analyses lead to interesting physical insights as well as to the design of new cells with potentially improved photovoltaic parameters.

  9. Material efficiency: providing material services with less material production

    PubMed Central

    Allwood, Julian M.; Ashby, Michael F.; Gutowski, Timothy G.; Worrell, Ernst

    2013-01-01

    Material efficiency, as discussed in this Meeting Issue, entails the pursuit of the technical strategies, business models, consumer preferences and policy instruments that would lead to a substantial reduction in the production of high-volume energy-intensive materials required to deliver human well-being. This paper, which introduces a Discussion Meeting Issue on the topic of material efficiency, aims to give an overview of current thinking on the topic, spanning environmental, engineering, economics, sociology and policy issues. The motivations for material efficiency include reducing energy demand, reducing the emissions and other environmental impacts of industry, and increasing national resource security. There are many technical strategies that might bring it about, and these could mainly be implemented today if preferred by customers or producers. However, current economic structures favour the substitution of material for labour, and consumer preferences for material consumption appear to continue even beyond the point at which increased consumption provides any increase in well-being. Therefore, policy will be required to stimulate material efficiency. A theoretically ideal policy measure, such as a carbon price, would internalize the externality of emissions associated with material production, and thus motivate change directly. However, implementation of such a measure has proved elusive, and instead the adjustment of existing government purchasing policies or existing regulations— for instance to do with building design, planning or vehicle standards—is likely to have a more immediate effect. PMID:23359746

  10. Material efficiency: providing material services with less material production.

    PubMed

    Allwood, Julian M; Ashby, Michael F; Gutowski, Timothy G; Worrell, Ernst

    2013-03-13

    Material efficiency, as discussed in this Meeting Issue, entails the pursuit of the technical strategies, business models, consumer preferences and policy instruments that would lead to a substantial reduction in the production of high-volume energy-intensive materials required to deliver human well-being. This paper, which introduces a Discussion Meeting Issue on the topic of material efficiency, aims to give an overview of current thinking on the topic, spanning environmental, engineering, economics, sociology and policy issues. The motivations for material efficiency include reducing energy demand, reducing the emissions and other environmental impacts of industry, and increasing national resource security. There are many technical strategies that might bring it about, and these could mainly be implemented today if preferred by customers or producers. However, current economic structures favour the substitution of material for labour, and consumer preferences for material consumption appear to continue even beyond the point at which increased consumption provides any increase in well-being. Therefore, policy will be required to stimulate material efficiency. A theoretically ideal policy measure, such as a carbon price, would internalize the externality of emissions associated with material production, and thus motivate change directly. However, implementation of such a measure has proved elusive, and instead the adjustment of existing government purchasing policies or existing regulations-- for instance to do with building design, planning or vehicle standards--is likely to have a more immediate effect.

  11. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1982-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons and methods for making such materials. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  12. Thermoelectric materials and devices

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor); Talcott, Noel A. (Inventor)

    2011-01-01

    New thermoelectric materials comprise highly [111]-oriented twinned group IV alloys on the basal plane of trigonal substrates, which exhibit a high thermoelectric figure of merit and good material performance, and devices made with these materials.

  13. Closed cellular materials for smart materials

    NASA Astrophysics Data System (ADS)

    Kishimoto, Satoshi

    2008-11-01

    New methods to fabricate a metallic closed cellular material for smart materials using an isostatic pressing, spark plasma sintering (SPS) method and penetrating method are introduced. Powder particles of polymer or ceramics coated with a metal layer using electro-less plating were pressed into pellets and sintered at high temperatures by sintering at high temperature. Also these powder particles were sintered by spark plasma sintering (SPS) method. Also a many kinds of closed cellular materials with different materials of cell walls and different materials inside of the cell were tried to fabricate. The physical, mechanical and thermal properties of this material were measured. The results of the compressive tests show that this material has the different stress-strain curves among the specimens that have different thickness of the cell walls and the sintering temperatures of the specimens affect the compressive strength of each specimen. Also, the results of the compressive tests show that this material has high-energy absorption and Young's modulus of this material depends on the thickness of the cell walls and sintering conditions. The internal friction of this material was measured and the results show that this internal friction is same as that of pure aluminum.

  14. Removal of Hazardous Pollutants from Wastewaters: Applications of TiO 2 -SiO 2 Mixed Oxide Materials

    DOE PAGES

    Rasalingam, Shivatharsiny; Peng, Rui; Koodali, Ranjit T.

    2014-01-01

    The direct release of untreated wastewaters from various industries and households results in the release of toxic pollutants to the aquatic environment. Advanced oxidation processes (AOP) have gained wide attention owing to the prospect of complete mineralization of nonbiodegradable organic substances to environmentally innocuous products by chemical oxidation. In particular, heterogeneous photocatalysis has been demonstrated to have tremendous promise in water purification and treatment of several pollutant materials that include naturally occurring toxins, pesticides, and other deleterious contaminants. In this work, we have reviewed the different removal techniques that have been employed for water purification. In particular, the applicationmore » of TiO 2 -SiO 2 binary mixed oxide materials for wastewater treatment is explained herein, and it is evident from the literature survey that these mixed oxide materials have enhanced abilities to remove a wide variety of pollutants.« less

  15. Nonmetallic materials handbook. Volume 1: Epoxy materials

    NASA Technical Reports Server (NTRS)

    Podlaseck, S. E.

    1979-01-01

    Thermochemical and other properties data is presented for the following types of epoxy materials: adhesives, coatings finishes, inks, electrical insulation, encapsulants, sealants, composite laminates, tapes, and thermal insulators.

  16. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-04-07

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  17. Advanced Ceramic Armor Materials

    DTIC Science & Technology

    1990-05-11

    materials, toughened alumina, fiber -reinforced glass matrix composites, and multilayer-gradient materials for ballistic testing. Fabrication and...material systems: Multilayer advanced armor materials consisting of a hard ceramic faceplate bonded to a graphite fiber -reinforced glass matrix...toughened alumina, and fiber - applied studies of advanced reinforced ceramic matrix glass and glass -ceramic composites for ballistic testing. technologies

  18. Tritium breeding materials

    SciTech Connect

    Hollenberg, G.W.; Johnson, C.E.; Abdou, M.

    1984-03-01

    Tritium breeding materials are essential to the operation of D-T fusion facilities. Both of the present options - solid ceramic breeding materials and liquid metal materials are reviewed with emphasis not only on their attractive features but also on critical materials issues which must be resolved.

  19. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-01-01

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  20. Immunohistochemistry staining for mismatch repair proteins: the endoscopic biopsy material provides useful and coherent results.

    PubMed

    Vilkin, Alex; Leibovici-Weissman, Ya'ara; Halpern, Marisa; Morgenstern, Sara; Brazovski, Eli; Gingold-Belfer, Rachel; Wasserberg, Nir; Brenner, Baruch; Niv, Yaron; Sneh-Arbib, Orly; Levi, Zohar

    2015-11-01

    Immunohistochemistry (IHC) testing for mismatch repair proteins (MMRP) in patients with colorectal cancer can be performed on endoscopic biopsy material or the surgical resection material. Data are continuing to accumulate regarding the deleterious effect of neoadjuvant chemoradiation on MMRP expression. However, despite continuing rise in the use of endoscopic biopsies for IHC, most pathology departments still use mainly the surgical materials for IHC testing. In this study we compared the quality of stains among 96 colon cancer subjects with paired endoscopic and surgical material available for MLH1, MSH2, MSH6, and PMS2 stains (96 × 4, yielding 384 paired stains). Each slide received both a quantitative score (immunoreactivity [0-3] × percent positivity [0-4]) and a qualitative score (absent; weak and focal; strong). The quantitative scores of all MMRP were significantly higher among the endoscopic material (P<.001 for all). In 358 pairs (93.2%), both the endoscopic and operative material stained either strong (322, 83.9%) or absent (36, 9.4%). In 26 pairs (6.8%), the endoscopic material stained strong, whereas the operative material stained focal and weak. No endoscopic biopsy materials stained focal and weak. Our findings indicate that the biopsy material may provide more coherent results. Although these results may indicate that biopsy material provides coherent and useful results, it is yet to be determined if the demonstrated differences pose a real clinical problem in interpreting final results of IHC staining of such kind. Hence, we suggest that when available, the endoscopic material rather than the operative one should serve as the primary substrate for IHC staining.

  1. Materials Analysis and Modeling of Underfill Materials.

    SciTech Connect

    Wyatt, Nicholas B; Chambers, Robert S.

    2015-08-01

    The thermal-mechanical properties of three potential underfill candidate materials for PBGA applications are characterized and reported. Two of the materials are a formulations developed at Sandia for underfill applications while the third is a commercial product that utilizes a snap-cure chemistry to drastically reduce cure time. Viscoelastic models were calibrated and fit using the property data collected for one of the Sandia formulated materials. Along with the thermal-mechanical analyses performed, a series of simple bi-material strip tests were conducted to comparatively analyze the relative effects of cure and thermal shrinkage amongst the materials under consideration. Finally, current knowledge gaps as well as questions arising from the present study are identified and a path forward presented.

  2. Nanocrystalline ceramic materials

    DOEpatents

    Siegel, R.W.; Nieman, G.W.; Weertman, J.R.

    1994-06-14

    A method is disclosed for preparing a treated nanocrystalline metallic material. The method of preparation includes providing a starting nanocrystalline metallic material with a grain size less than about 35 nm, compacting the starting nanocrystalline metallic material in an inert atmosphere and annealing the compacted metallic material at a temperature less than about one-half the melting point of the metallic material. 19 figs.

  3. Puncture detecting barrier materials

    DOEpatents

    Hermes, R.E.; Ramsey, D.R.; Stampfer, J.F.; Macdonald, J.M.

    1998-03-31

    A method and apparatus for continuous real-time monitoring of the integrity of protective barrier materials, particularly protective barriers against toxic, radioactive and biologically hazardous materials has been developed. Conductivity, resistivity or capacitance between conductive layers in the multilayer protective materials is measured by using leads connected to electrically conductive layers in the protective barrier material. The measured conductivity, resistivity or capacitance significantly changes upon a physical breach of the protective barrier material. 4 figs.

  4. Puncture detecting barrier materials

    DOEpatents

    Hermes, Robert E.; Ramsey, David R.; Stampfer, Joseph F.; Macdonald, John M.

    1998-01-01

    A method and apparatus for continuous real-time monitoring of the integrity of protective barrier materials, particularly protective barriers against toxic, radioactive and biologically hazardous materials has been developed. Conductivity, resistivity or capacitance between conductive layers in the multilayer protective materials is measured by using leads connected to electrically conductive layers in the protective barrier material. The measured conductivity, resistivity or capacitance significantly changes upon a physical breach of the protective barrier material.

  5. Orbital foamed material extruder

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S. (Inventor)

    2009-01-01

    This invention is a process for producing foamed material in space comprising the steps of: rotating the material to simulate the force of gravity; heating the rotating material until it is molten; extruding the rotating, molten material; injecting gas into the extruded, rotating, molten material to produce molten foamed material; allowing the molten foamed material to cool to below melting temperature to produce the foamed material. The surface of the extruded foam may be heated to above melting temperature and allowed to cool to below melting temperature. The extruded foam may also be cut to predetermined length. The starting material may be metal or glass. Heating may be accomplished by electrical heating elements or by solar heating.

  6. Enhanced magnetocaloric effect material

    DOEpatents

    Lewis, Laura J. H.

    2006-07-18

    A magnetocaloric effect heterostructure having a core layer of a magnetostructural material with a giant magnetocaloric effect having a magnetic transition temperature equal to or greater than 150 K, and a constricting material layer coated on at least one surface of the magnetocaloric material core layer. The constricting material layer may enhance the magnetocaloric effect by restriction of volume changes of the core layer during application of a magnetic field to the heterostructure. A magnetocaloric effect heterostructure powder comprising a plurality of core particles of a magnetostructural material with a giant magnetocaloric effect having a magnetic transition temperature equal to or greater than 150 K, wherein each of the core particles is encapsulated within a coating of a constricting material is also disclosed. A method for enhancing the magnetocaloric effect within a giant magnetocaloric material including the step of coating a surface of the magnetocaloric material with a constricting material is disclosed.

  7. Joining of dissimilar materials

    DOEpatents

    Tucker, Michael C; Lau, Grace Y; Jacobson, Craig P

    2012-10-16

    A method of joining dissimilar materials having different ductility, involves two principal steps: Decoration of the more ductile material's surface with particles of a less ductile material to produce a composite; and, sinter-bonding the composite produced to a joining member of a less ductile material. The joining method is suitable for joining dissimilar materials that are chemically inert towards each other (e.g., metal and ceramic), while resulting in a strong bond with a sharp interface between the two materials. The joining materials may differ greatly in form or particle size. The method is applicable to various types of materials including ceramic, metal, glass, glass-ceramic, polymer, cermet, semiconductor, etc., and the materials can be in various geometrical forms, such as powders, fibers, or bulk bodies (foil, wire, plate, etc.). Composites and devices with a decorated/sintered interface are also provided.

  8. Materials science and engineering

    SciTech Connect

    Lesuer, D.R.

    1997-02-01

    During FY-96, work within the Materials Science and Engineering Thrust Area was focused on material modeling. Our motivation for this work is to develop the capability to study the structural response of materials as well as material processing. These capabilities have been applied to a broad range of problems, in support of many programs at Lawrence Livermore National Laboratory. These studies are described in (1) Strength and Fracture Toughness of Material Interfaces; (2) Damage Evolution in Fiber Composite Materials; (3) Flashlamp Envelope Optical Properties and Failure Analysis; (4) Synthesis and Processing of Nanocrystalline Hydroxyapatite; and (5) Room Temperature Creep Compliance of Bulk Kel-E.

  9. Comprehensive Nuclear Materials

    SciTech Connect

    Konings, Dr. Rudy J. M.; Allen, Todd R.; Stoller, Roger E; Yamanaka, Prof. Shinsuke

    2012-01-01

    This book encompasses a rich seam of current information on the vast and multidisciplinary field of nuclear materials employed in fission and prototype fusion systems. Discussion includes both historical and contemporary international research in nuclear materials, from Actinides to Zirconium alloys, from the worlds leading scientists and engineers. Synthesizes pertinent current science to support the selection, assessment, validation and engineering of materials in extreme nuclear environments. The work discusses the major classes of materials suitable for usage in nuclear fission, fusion reactors and high power accelerators, and for diverse functions in fuels, cladding, moderator and control materials, structural, functional, and waste materials.

  10. Nondestructive material characterization

    DOEpatents

    Deason, Vance A.; Johnson, John A.; Telschow, Kenneth L.

    1991-01-01

    A method and apparatus for nondestructive material characterization, such as identification of material flaws or defects, material thickness or uniformity and material properties such as acoustic velocity. The apparatus comprises a pulsed laser used to excite a piezoelectric (PZ) transducer, which sends acoustic waves through an acoustic coupling medium to the test material. The acoustic wave is absorbed and thereafter reflected by the test material, whereupon it impinges on the PZ transducer. The PZ transducer converts the acoustic wave to electrical impulses, which are conveyed to a monitor.

  11. Materials Test Branch

    NASA Technical Reports Server (NTRS)

    Gordon, Gail

    2012-01-01

    The Materials Test Branch resides at Marshall Space Flight Center's Materials and Processing laboratory and has a long history of supporting NASA programs from Mercury to the recently retired Space Shuttle. The Materials Test Branch supports its customers by supplying materials testing expertise in a wide range of applications. The Materials Test Branch is divided into three Teams, The Chemistry Team, The Tribology Team and the Mechanical Test Team. Our mission and goal is to provide world-class engineering excellence in materials testing with a special emphasis on customer service.

  12. Materials Discovery: Informatic Strategies for Optical Materials

    SciTech Connect

    Ferris, Kim F.; Webb-Robertson, Bobbie-Jo M.; Jones, Dumont M.

    2007-01-15

    Information-based materials discovery offers a structured method to evolve materials signatures based upon their physical properties, and to direct searches using performance-based criteria. In this current paper, we focus on the crystal structure aspects of an optical material and construct an information-based model to determine the proclivity of a particular AB composition to exhibit multiple crystal system behavior. Exploratory data methods used both supervised (support-vector machines) and unsupervised (disorder-reduction and principal-component) classification methods for structural signature development; revealing complementary valid signatures. Examination of the relative contributions of the materials chemistry descriptors within these signatures indicates a strong role for Mendeleev number chemistry which must be balanced against the cationic/anionic radius ratio and electronegativity differences of constituents within the unit cell.

  13. Materials science and engineering

    SciTech Connect

    Lesuer, D R

    1998-01-01

    During FY-97, work within the Materials Science and Engineering thrust area was focused on material modeling. Their motivation for this work is to develop the capability to study the structural response of materials as well as materials processing. These capabilities have been applied to a broad range of problems, which support many programs at Lawrence Livermore National Laboratory. Recent examples of structural response problems studied include material fracture (such as interface failure), damage in laser optics, the response of weapons components (such as high explosives) and the failure of composite materials. For materials processing, typical problems studied include metal forming, laser processing, casting, and heat treating. To improve our ability to model material behavior, much of the work involves developing new material models and failure models, as well as applying the codes to new problems. Most investigations involve experimental studies to gather basic information on material response and to validate codes or material models. Projects are inherently multi-disciplinary, involving several investigators with expertise in materials and mechanics. The thrust area studies for FY-97 are described in the following three articles: (1) Evolution of Anisotropic Yield Behavior; (2) Modeling of She Localization in Materials; and (3) Modeling of Casting Microstructures and Defects.

  14. EC Transmission Line Materials

    SciTech Connect

    Bigelow, Tim S

    2012-05-01

    The purpose of this document is to identify materials acceptable for use in the US ITER Project Office (USIPO)-supplied components for the ITER Electron cyclotron Heating and Current Drive (ECH&CD) transmission lines (TL), PBS-52. The source of material property information for design analysis shall be either the applicable structural code or the ITER Material Properties Handbook. In the case of conflict, the ITER Material Properties Handbook shall take precedence. Materials selection, and use, shall follow the guidelines established in the Materials Assessment Report (MAR). Materials exposed to vacuum shall conform to the ITER Vacuum Handbook. [Ref. 2] Commercial materials shall conform to the applicable standard (e.g., ASTM, JIS, DIN) for the definition of their grade, physical, chemical and electrical properties and related testing. All materials for which a suitable certification from the supplier is not available shall be tested to determine the relevant properties, as part of the procurement. A complete traceability of all the materials including welding materials shall be provided. Halogenated materials (example: insulating materials) shall be forbidden in areas served by the detritiation systems. Exceptions must be approved by the Tritium System and Safety Section Responsible Officers.

  15. Renewable smart materials

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Chan; Mun, Seongcheol; Ko, Hyun-U.; Zhai, Lindong; Kafy, Abdullahil; Kim, Jaehwan

    2016-07-01

    The use of renewable materials is essential in future technologies to harmonize with our living environment. Renewable materials can maintain our resources from the environment so as to overcome degradation of natural environmental services and diminished productivity. This paper reviews recent advancement of renewable materials for smart material applications, including wood, cellulose, chitin, lignin, and their sensors, actuators and energy storage applications. To further improve functionality of renewable materials, hybrid composites of inorganic functional materials are introduced by incorporating carbon nanotubes, titanium dioxide and tin oxide conducting polymers and ionic liquids. Since renewable materials have many advantages of biocompatible, sustainable, biodegradable, high mechanical strength and versatile modification behaviors, more research efforts need to be focused on the development of renewable smart materials.

  16. FUEL CELL ELECTRODE MATERIALS

    DTIC Science & Technology

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  17. Nanostructured composite reinforced material

    DOEpatents

    Seals, Roland D [Oak Ridge, TN; Ripley, Edward B [Knoxville, TN; Ludtka, Gerard M [Oak Ridge, TN

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  18. Sustainable Materials Management

    EPA Pesticide Factsheets

    To introduce businesses, NGOs, and government officials to the concept of Sustainable Materials Management (SMM). To provide tools to allow stakeholders to take a lifecycle approach managing their materials, & to encourage them to join a SMM challenge.

  19. Bridged graphite oxide materials

    NASA Technical Reports Server (NTRS)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  20. Ultrasonic material property determinations

    NASA Technical Reports Server (NTRS)

    Serabian, S.

    1986-01-01

    The use and potential offered by ultrasonic velocity and attenuation measurements to determine and/or monitor material properties is explored. The basis for such unique measurements along with examples of materials from a variety of industries are presented.

  1. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1982-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  2. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1983-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  3. Materials modelling in London

    NASA Astrophysics Data System (ADS)

    Ciudad, David

    2016-04-01

    Angelos Michaelides, Professor in Theoretical Chemistry at University College London (UCL) and co-director of the Thomas Young Centre (TYC), explains to Nature Materials the challenges in materials modelling and the objectives of the TYC.

  4. Improvisation: Teaching Materials.

    ERIC Educational Resources Information Center

    Kuzmich, John A., Jr.

    1980-01-01

    The past, present and future of music improvisation is discussed. Resources for piano, guitar, elementary general music materials, and electronic music materials are included, along with addresses of publishers. The emphasis is on jazz. (KC)

  5. Silicone azide fireproof material

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Finely powdered titanium oxide was added to silicone azide as the sintering agent to produce a nonflammable material. Mixing proportions, physical properties, and chemical composition of the fireproofing material are included.

  6. Supplements to Textbook Materials.

    ERIC Educational Resources Information Center

    Holmes, Ken

    1994-01-01

    Describes the many kinds of materials that English teachers can draw upon to enrich and expand students' experiences with literature. Outlines ancillary materials used to supplement the study of William Shakespeare's "Julius Caesar." (HB)

  7. Impact tolerant material

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S. (Inventor)

    1990-01-01

    A material is protected from acoustic shock waves generated by impacting projectiles by means of a backing. The backing has an acoustic impedance that efficiently couples the acoustic energy out of the material.

  8. Bibliography of AV Materials.

    ERIC Educational Resources Information Center

    Friedstein, Harriet, Ed.

    1981-01-01

    Lists commercially available audiovisual materials by subject area. Includes title, producer (addresses given), catalog number, format (film, filmstrip, cassette, slides), and prices. Subject areas include: elements; equilibrium; gases; laboratory techniques and experiments; general chemistry; introductory materials (including mathematics); and…

  9. Lightweight Materials & Structures

    NASA Video Gallery

    The Lightweight Materials and Structures (LMS) project will mature high-payoff structures and materials technologies that have direct application to NASA’s future space exploration needs.One of the...

  10. Pantoea agglomerans: a mysterious bacterium of evil and good. Part II--Deleterious effects: Dust-borne endotoxins and allergens--focus on grain dust, other agricultural dusts and wood dust.

    PubMed

    Dutkiewicz, Jacek; Mackiewicz, Barbara; Lemieszek, Marta Kinga; Golec, Marcin; Skórska, Czesława; Góra-Florek, Anna; Milanowski, Janusz

    2016-01-01

    Pantoea agglomerans, a Gram-negative bacterium developing in a variety of plants as epiphyte or endophyte is particularly common in grain and grain dust, and has been identified by an interdisciplinary group from Lublin, eastern Poland, as a causative agent of work-related diseases associated with exposure to grain dust and other agricultural dusts. The concentration of P. agglomerans in grain as well as in the settled grain and flour dust was found to be high, ranging from 10(4)-10(8) CFU/g, while in the air polluted with grain or flour dust it ranged from 10(3)-10(5) CFU/m(3) and formed 73.2-96% of the total airborne Gram-negative bacteria. The concentration of P. agglomerans was also relatively high in the air of the facilities processing herbs and other plant materials, while it was lower in animal farms and in wood processing facilities. Pantoea agglomerans produces a biologically-potent endotoxin (cell wall lipopolysaccharide, LPS). The significant part of this endotoxin occurs in dusts in the form of virus-sized globular nanoparticles measuring 10-50 nm that could be described as the 'endotoxin super-macromolecules'. A highly significant relationship was found (R=0.804, P=0.000927) between the concentration of the viable P. agglomerans in the air of various agricultural and wood industry settings and the concentration of bacterial endotoxin in the air, as assessed by the Limulus test. Although this result may be interfered by the presence of endotoxin produced by other Gram-negative species, it unequivocally suggests the primary role of the P. agglomerans endotoxin as an adverse agent in the agricultural working environment, causing toxic pneumonitis (ODTS). Numerous experiments by the inhalation exposure of animals to various extracts of P. agglomerans strains isolated from grain dust, including endotoxin isolated with trichloroacetic acid (LPS-TCA), endotoxin nanoparticles isolated in sucrose gradient (VECN), and mixture of proteins and endotoxin obtained

  11. Smart materials and structures

    NASA Technical Reports Server (NTRS)

    Rogowski, Robert S.; Heyman, Joseph S.

    1993-01-01

    Embedded optical fibers allow not only the cure-monitoring and in-service lifetime measurements of composite materials, but the NDE of material damage and degradation with aging. The capabilities of such damage-detection systems have been extended to allow the quantitative determination of 2D strain in materials by several different methods, including the interferometric and the numerical. It remains to be seen, what effect the embedded fibers have on the strength of the 'smart' materials created through their incorporation.

  12. Materials Genome Initiative Element

    NASA Technical Reports Server (NTRS)

    Vickers, John

    2015-01-01

    NASA is committed to developing new materials and manufacturing methods that can enable new missions with ever increasing mission demands. Typically, the development and certification of new materials and manufacturing methods in the aerospace industry has required more than 20 years of development time with a costly testing and certification program. To reduce the cost and time to mature these emerging technologies, NASA is developing computational materials tools to improve understanding of the material and guide the certification process.

  13. Electronics materials research

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The electronic materials and is aimed at the establishment of quantitative relationships underlying crystal growth parameters, materials properties, electronic characteristics and device applications. The overall program evolves about the following main thrust areas: (1) crystal growth novel approaches to engineering of semiconductor materials; (2) investigation of materials properties and electronic characteristics on a macro and microscale; (3) surface properties and surface interactions with the bulk and ambients; (4) electronic properties controlling device applications and device performance.

  14. Synthesis and Characterization of Polyphosphazene Materials for Advanced Lithium-Water Batteries

    SciTech Connect

    Mason K. Harrup; Thomas A. Luther; Frederick F. Stewart; Christopher J. Orme; Mark L. Stone; William F. Bauer

    2007-08-01

    Development of long-lived high-energy lithium-water batteries hinges upon developing solid polymer electrolytes (SPEs) with the appropriate properties. These polymer membranes paradoxically must allow lithium atoms to pass from the metallic surface, oxidize to the ionic form, and then pass through the membrane to the water outside. At the same time, the membrane must exclude all water, tramp ions, and deleterious gases such as oxygen and carbon dioxide. SPE membranes are the leading choice for lithium-water batteries however, because current non-membrane approaches being pursued by other research groups suffer from two insurmountable problems - storage and non-productive energy loss via direct lithium/water reaction. In this paper, we present the results of our latest investigations into the transport of water and permanent gasses, such as carbon dioxide, through polyphosphazene SPE materials designed to address the challenges inherent in lithium water batteries.

  15. Green materials science and engineering reduces biofouling: approaches for medical and membrane-based technologies

    PubMed Central

    Dobosz, Kerianne M.; Kolewe, Kristopher W.; Schiffman, Jessica D.

    2015-01-01

    Numerous engineered and natural environments suffer deleterious effects from biofouling and/or biofilm formation. For instance, bacterial contamination on biomedical devices pose serious health concerns. In membrane-based technologies, such as desalination and wastewater reuse, biofouling decreases membrane lifetime, and increases the energy required to produce clean water. Traditionally, approaches have combatted bacteria using bactericidal agents. However, due to globalization, a decline in antibiotic discovery, and the widespread resistance of microbes to many commercial antibiotics and metallic nanoparticles, new materials, and approaches to reduce biofilm formation are needed. In this mini-review, we cover the recent strategies that have been explored to combat microbial contamination without exerting evolutionary pressure on microorganisms. Renewable feedstocks, relying on structure-property relationships, bioinspired/nature-derived compounds, and green processing methods are discussed. Greener strategies that mitigate biofouling hold great potential to positively impact human health and safety. PMID:25852659

  16. Green materials science and engineering reduces biofouling: approaches for medical and membrane-based technologies.

    PubMed

    Dobosz, Kerianne M; Kolewe, Kristopher W; Schiffman, Jessica D

    2015-01-01

    Numerous engineered and natural environments suffer deleterious effects from biofouling and/or biofilm formation. For instance, bacterial contamination on biomedical devices pose serious health concerns. In membrane-based technologies, such as desalination and wastewater reuse, biofouling decreases membrane lifetime, and increases the energy required to produce clean water. Traditionally, approaches have combatted bacteria using bactericidal agents. However, due to globalization, a decline in antibiotic discovery, and the widespread resistance of microbes to many commercial antibiotics and metallic nanoparticles, new materials, and approaches to reduce biofilm formation are needed. In this mini-review, we cover the recent strategies that have been explored to combat microbial contamination without exerting evolutionary pressure on microorganisms. Renewable feedstocks, relying on structure-property relationships, bioinspired/nature-derived compounds, and green processing methods are discussed. Greener strategies that mitigate biofouling hold great potential to positively impact human health and safety.

  17. Optimal Super Dielectric Material

    DTIC Science & Technology

    2015-09-01

    electrically insulating materials filled to the point of incipient wetness (paste consistency) with liquids containing dissolved ions. This work...109. This strongly supports the fundamental hypothesis of SDM: In the presence of an electric field any electrically insulating, porous material...ABSTRACT The results of this study establish that powder-based super dielectric materials (SDM) are a large family of porous electrically

  18. Bibliography of Citizenship Materials

    ERIC Educational Resources Information Center

    CASAS - Comprehensive Adult Student Assessment Systems (NJ1), 2008

    2008-01-01

    The 2008 CASAS "Bibliography of Citizenship Materials" lists available instructional resources for citizenship education. It focuses on materials appropriate for preparing people for the naturalization process and the standardized citizenship examination. Resources include textbooks, audio materials, software and Videos/DVDs. The bibliography also…

  19. Portuguese Language Teaching Materials.

    ERIC Educational Resources Information Center

    Hoge, Henry W.

    This annotated bibliography is a selective list of the most useful reference and teaching materials for Portuguese language study. The listing includes both traditional materials and the few items available which reflect the current advances of linguistic theory. Commercially prepared materials known to be out of print have not been included.…

  20. Materials Flow and Sustainability

    USGS Publications Warehouse

    Sznopek, John L.; Brown, William M.

    1998-01-01

    Materials extracted from the Earth are necessary to produce our most fundamental needs – food, clothing, and shelter. Materials are needed to maintain and improve our standard of living. Understanding the whole system of materials flow, from source to ultimate disposition, can help us better manage the use of natural resources and protect the environment.

  1. Paramagnetic and Diamagnetic Materials

    ERIC Educational Resources Information Center

    Thompson, Frank

    2011-01-01

    Paramagnetic and diamagnetic materials are now generally known as the "Cinderella" materials of the magnetic world. However, susceptibility measurements made on these materials in the past have revealed many details about the molecular bonding and the atomic structure of the so-called "transition" elements. Indeed, the magnetic moment of neodymium…

  2. Advanced neutron absorber materials

    DOEpatents

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  3. Energy Education Materials Bibliography.

    ERIC Educational Resources Information Center

    Minnesota State Energy Agency, St. Paul.

    This is an annotated bibliography of selected energy education materials. The materials included in this document are indexed according to grade level and according to whether they are background materials or classroom activities. Each of the 100 items listed were evaluated and included into either the "A" list or the "B" list.…

  4. Advanced Materials Technology

    NASA Technical Reports Server (NTRS)

    Blankenship, C. P. (Compiler); Teichman, L. A. (Compiler)

    1982-01-01

    Composites, polymer science, metallic materials (aluminum, titanium, and superalloys), materials processing technology, materials durability in the aerospace environment, ceramics, fatigue and fracture mechanics, tribology, and nondestructive evaluation (NDE) are discussed. Research and development activities are introduced to the nonaerospace industry. In order to provide a convenient means to help transfer aerospace technology to the commercial mainstream in a systematic manner.

  5. Advances in dental materials.

    PubMed

    Fleming, Garry J P

    2014-05-01

    The dental market is replete with new resorative materials marketed on the basis of novel technological advances in materials chemistry, bonding capability or reduced operator time and/or technique sensitivity. This paper aims to consider advances in current materials, with an emphasis on their role in supporting contemporary clinical practice.

  6. Fingerprinting Of Materials

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1994-01-01

    Collection of three reports surveys emerging technology of chemical fingerprinting, which can be defined, loosely, as systematic application of modern methods of analysis to determine elemental or molecular compositions of materials, measure relative amounts of constituents of materials, and/or measure other relevant properties of materials.

  7. Hierarchical cellular materials

    SciTech Connect

    Gibson, L.J.

    1991-12-31

    In this paper a method for estimating the contributions of both the composite and the cellular microstructures to the overall material properties and the mechanical efficiency of natural cellular solids will be described. The method will be demonstrated by focusing on the Young`s modulus; similar techniques can be used for other material properties. The results suggest efficient microstructures for engineered cellular materials.

  8. Hierarchical cellular materials

    SciTech Connect

    Gibson, L.J.

    1991-01-01

    In this paper a method for estimating the contributions of both the composite and the cellular microstructures to the overall material properties and the mechanical efficiency of natural cellular solids will be described. The method will be demonstrated by focusing on the Young's modulus; similar techniques can be used for other material properties. The results suggest efficient microstructures for engineered cellular materials.

  9. Survival Learning Materials.

    ERIC Educational Resources Information Center

    Wilson, Robert M.; Barnes, Marcia M.

    This booklet is designed to provide some starter ideas for teachers to use in developing their own packet of learning materials. The procedures suggested and the examples included are literally starters. "Introduction to Survival Learning Materials" presents some procedures to help teachers get started in developing materials. "Following…

  10. Fusion reactor materials

    SciTech Connect

    none,

    1989-01-01

    This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics.

  11. Materials for Space Exploration

    NASA Technical Reports Server (NTRS)

    Robertson, Luke B.; Williams, Martha

    2010-01-01

    Topics include a lab overview, testing and processing equipment, hemochromic hydrogen sensors, antimicrobial materials, wire system materials, CNT ink formulations, CNT ink dust screens, CNT ink printed circuitry, cryogenic materials development, fire and polymers, the importance of lighting, electric lighting systems, LED for plant growth, and carbon nanotube fiber filaments.

  12. [Refugee Materials Center Bibliography].

    ERIC Educational Resources Information Center

    Department of Education, Kansas City, MO. Regional Office 7.

    The citations in this bibliography include textbooks, other instructional materials, and resource materials that can be used in teaching refugees in the United States. The title entries are grouped in series consisting of: (1) textbooks, workbooks, and other instuctional materials on teaching English to non-English speakers; (2) curricular and…

  13. Safer Aviation Materials Tested

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    2001-01-01

    A series of thermally stable polymer samples were tested. These materials are called low heat release materials and are designed for aircraft interior decorative materials. The materials are designed to give off a minimum amount of noxious gases when heated, which increases the possibility that people can escape from a burning aircraft. New cabin materials have suitably low heat release so that fire does not spread, toxic chemicals are not given off, and the fire-emergency escape time for crew and passengers is lengthened. These low heat-release materials have a variety of advantages and applications: interiors for ground-based facilities, interiors of space vehicles, and many commercial fire-protection environments. A microscale combustion calorimeter at the Federal Aviation Administration's (FAA) Technical Center tested NASA Langley Research Center materials samples. The calorimeter is shown. A sharp, quantitative, and reproducible heat-release-rate peak is obtained in the microscale heat-release-rate test. The newly tested NASA materials significantly reduced the heat release capacity and total heat release. The thermal stability and flammability behavior of the samples was very good. The new materials demonstrated a factor of 4 reduction in total heat release over ULTEM (a currently used material). This information is provided in the following barchart. In other tests, the materials showed greater than a factor 9 reduction in heat-release capacity over ULTEM. The newly tested materials were developed for low dielectric constant, low color, and good solubility. A scale up of the material samples is needed to determine the repeatability of the performance in larger samples. Larger panels composed of the best candidate materials will be tested in a larger scale FAA Technical Center fire facility. The NASA Glenn Research Center, Langley (Jeff Hinkley), and the FAA Technical Center (Richard Lyon) cooperatively tested these materials for the Accident Mitigation

  14. Tailored Porous Materials

    SciTech Connect

    BARTON,THOMAS J.; BULL,LUCY M.; KLEMPERER,WALTER G.; LOY,DOUGLAS A.; MCENANEY,BRIAN; MISONO,MAKOTO; MONSON,PETER A.; PEZ,GUIDO; SCHERER,GEORGE W.; VARTULI,JAMES C.; YAGHI,OMAR M.

    1999-11-09

    Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol-gel derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities.

  15. Self-healing materials.

    PubMed

    Hager, Martin D; Greil, Peter; Leyens, Christoph; van der Zwaag, Sybrand; Schubert, Ulrich S

    2010-12-14

    Self-healing materials are able to partially or completely heal damage inflicted on them, e.g., crack formation; it is anticipated that the original functionality can be restored. This article covers the design and generic principles of self-healing materials through a wide range of different material classes including metals, ceramics, concrete, and polymers. Recent key developments and future challenges in the field of self-healing materials are summarised, and generic, fundamental material-independent principles and mechanism are discussed and evaluated.

  16. Femtosecond laser materials processing

    NASA Astrophysics Data System (ADS)

    Banks, Paul S.; Stuart, Brent C.; Komashko, Aleksey M.; Feit, Michael D.; Rubenchik, Alexander M.; Perry, Michael D.

    2000-05-01

    The use of femtosecond lasers allows materials processing of practically any material with extremely high precision and minimal collateral damage. Advantages over conventional laser machining (using pulses longer than a few tens of picoseconds) are realized by depositing the laser energy into the electrons of the material on a time scale short compared to the transfer time of this energy to the bulk of the material, resulting in increased ablation efficiency and negligible shock or thermal stress. The improvement in the morphology by using femtosecond pulses rather than nanosecond pulses has been studied in numerous materials from biological materials to dielectrics to metals. During the drilling process, we have observed the onset of small channels which drill faster than the surrounding material.

  17. Femtosecond Laser Materials Processing

    SciTech Connect

    Banks, P.S.; Stuart, B.C.; Komashko, A.M.; Feit, M.D.; Rubenchik, A.M.; Perry, M.D.

    2000-03-06

    The use of femtosecond lasers allows materials processing of practically any material with extremely high precision and minimal collateral damage. Advantages over conventional laser machining (using pulses longer than a few tens of picoseconds) are realized by depositing the laser energy into the electrons of the material on a time scale short compared to the transfer time of this energy to the bulk of the material, resulting in increased ablation efficiency and negligible shock or thermal stress. The improvement in the morphology by using femtosecond pulses rather than nanosecond pulses has been studied in numerous materials from biologic materials to dielectrics to metals. During the drilling process, we have observed the onset of small channels which drill faster than the surrounding material.

  18. Materials processing in space

    NASA Technical Reports Server (NTRS)

    Waldron, R. D.; Criswell, D. R.

    1982-01-01

    Processing-refining of raw materials from extraterrestrial sources is detailed for a space materials handling facility. The discussion is constrained to those steps necessary to separate desired components from raw or altered input ores, semi-purified feedstocks, or process scrap and convert the material into elements, alloys, and consumables. The materials are regarded as originating from dead satellites and boosters, lunar materials, and asteroids. Strong attention will be given to recycling reagent substances to avoid the necessity of transporting replacements. It is assumed that since no aqueous processes exist on the moon, the distribution of minerals will be homogeneous. The processing-refining scenario will include hydrochemical, pyrochemical, electrochemical, and physical techniques selected for the output mass rate/unit plant mass ratio. Flow charts of the various materials processing operations which could be performed with lunar materials are provided, noting the necessity of delivering several alloying elements from the earth due to scarcities on the moon.

  19. Materials research for fusion

    NASA Astrophysics Data System (ADS)

    Knaster, J.; Moeslang, A.; Muroga, T.

    2016-05-01

    Fusion materials research started in the early 1970s following the observation of the degradation of irradiated materials used in the first commercial fission reactors. The technological challenges of fusion energy are intimately linked with the availability of suitable materials capable of reliably withstanding the extremely severe operational conditions of fusion reactors. Although fission and fusion materials exhibit common features, fusion materials research is broader. The harder mono-energetic spectrum associated with the deuterium-tritium fusion neutrons (14.1 MeV compared to <2 MeV on average for fission neutrons) releases significant amounts of hydrogen and helium as transmutation products that might lead to a (at present undetermined) degradation of structural materials after a few years of operation. Overcoming the historical lack of a fusion-relevant neutron source for materials testing is an essential pending step in fusion roadmaps. Structural materials development, together with research on functional materials capable of sustaining unprecedented power densities during plasma operation in a fusion reactor, have been the subject of decades of worldwide research efforts underpinning the present maturity of the fusion materials research programme.

  20. Materials and structures

    NASA Technical Reports Server (NTRS)

    Saito, Theodore T.; Langenbeck, Sharon L.; Al-Jamily, Ghanim; Arnold, Joe; Barbee, Troy; Coulter, Dan; Dolgin, Ben; Fichter, Buck; George, Patricia; Gorenstein, Paul

    1992-01-01

    Materials and structures technology covers a wide range of technical areas. Some of the most pertinent issues for the Astrotech 21 missions include dimensionally stable structural materials, advanced composites, dielectric coatings, optical metallic coatings for low scattered light applications, low scattered light surfaces, deployable and inflatable structures (including optical), support structures in 0-g and 1-g environments, cryogenic optics, optical blacks, contamination hardened surfaces, radiation hardened glasses and crystals, mono-metallic telescopes and instruments, and materials characterization. Some specific examples include low coefficients of thermal expansion (CTE) structures (0.01 ppm/K), lightweight thermally stable mirror materials, thermally stable optical assemblies, high reliability/accuracy (1 micron) deployable structures, and characterization of nanometer level behavior of materials/structures for interferometry concepts. Large filled-aperture concepts will require materials with CTE's of 10(exp 9) at 80 K, anti-contamination coatings, deployable and erectable structures, composite materials with CTE's less than 0.01 ppm/K and thermal hysteresis, 0.001 ppm/K. Gravitational detection systems such as LAGOS will require rigid/deployable structures, dimensionally stable components, lightweight materials with low conductivity, and high stability optics. The Materials and Structures panel addressed these issues and the relevance of the Astrotech 21 mission requirements by dividing materials and structures technology into five categories. These categories, the necessary development, and applicable mission/program development phasing are summarized. For each of these areas, technology assessments were made and development plans were defined.

  1. Engineering Living Functional Materials

    PubMed Central

    2016-01-01

    Natural materials, such as bone, integrate living cells composed of organic molecules together with inorganic components. This enables combinations of functionalities, such as mechanical strength and the ability to regenerate and remodel, which are not present in existing synthetic materials. Taking a cue from nature, we propose that engineered ‘living functional materials’ and ‘living materials synthesis platforms’ that incorporate both living systems and inorganic components could transform the performance and the manufacturing of materials. As a proof-of-concept, we recently demonstrated that synthetic gene circuits in Escherichia coli enabled biofilms to be both a functional material in its own right and a materials-synthesis platform. To demonstrate the former, we engineered E. coli biofilms into a chemical-inducer-responsive electrical switch. To demonstrate the latter, we engineered E. coli biofilms to dynamically organize biotic-abiotic materials across multiple length scales, template gold nanorods, gold nanowires, and metal/semiconductor heterostructures, and synthesize semiconductor nanoparticles (Chen, A. Y. et al. (2014) Synthesis and patterning of tunable multiscale materials with engineered cells. Nat. Mater.13, 515–523.). Thus, tools from synthetic biology, such as those for artificial gene regulation, can be used to engineer the spatiotemporal characteristics of living systems and to interface living systems with inorganic materials. Such hybrids can possess novel properties enabled by living cells while retaining desirable functionalities of inorganic systems. These systems, as living functional materials and as living materials foundries, would provide a radically different paradigm of materials performance and synthesis–materials possessing multifunctional, self-healing, adaptable, and evolvable properties that are created and organized in a distributed, bottom-up, autonomously assembled, and environmentally sustainable manner. PMID

  2. Material behavior and materials problems in TFTR

    NASA Astrophysics Data System (ADS)

    Dylla, H. F.; Ulrickson, M. A.; Owens, D. K.; Heifetz, D. B.; Mills, B. E.; Pontau, A. E.; Wampler, W. R.; Doyle, B. L.; Lee, S. R.; Watson, R. D.; Croessmann, C. D.

    1988-07-01

    This paper reviews the experience with first-wall materials in TFTR over a 20 month period of operatiori during 1985-1987. Experience with the axisymmetric inner wall limiter, constructed of graphite tiles, is described, including the necessary conditioning procedures needed for impurity and particle control of high power (≤ 20 MW) neutral injection experiments. The thermal effects in disruptions have been quantified and no significant damage to the bumper limiter has occurred as a result of disruptions. Carbon and metal impurity redeposition effects have been quantified through surface analysis of wall samples. Estimates of the tritium retention in the graphite limiter tiles and redeposited carbon films have been made, based on analysis of deuterium retention in removed graphite tiles and wall samples. New limiter structures have been designed using a 2D carbon/carbon ( {C}/{C}) composite material for RF antenna protection. Laboratory tests of the important thermal, mechanical, and vacuum properties of {C}/{C} materials are described. Finally, the last series of experiments in TFTR with in-situ {Zr}/{Al} surface pumps are discussed. Problems with {Zr}/{Al} embrittlement have led to the removal of the getter material from the in-torus environment.

  3. Geothermal materials development

    SciTech Connect

    Kukacka, L.E.

    1982-01-01

    Among the most pressing problems constraining the development of geothermal energy is the lack of satisfactory component and system reliability. This is due to the unavailability, on a commercial scale, of cost-effective materials that can function in a wide range of geothermal environments and to the unavailability of a comprehensive body of directly relevant test data or materials selection experience. Suitable materials are needed for service in geothermal wells and in process plant equipment. For both situations, this requires materials that can withstand high-temperature, highly-corrosive, and scale-forming geothermal fluids. In addition to requiring a high degree of chemical and thermal resistance, the downhole environment places demands on the physical/mechanical properties of materials for components utilized in well drilling, completion, pumping, and logging. Technical and managerial assistance provided by Brookhaven in the program for studying these materials problems is described.

  4. Ultrasonic nondestructive materials characterization

    NASA Technical Reports Server (NTRS)

    Green, R. E., Jr.

    1986-01-01

    A brief review of ultrasonic wave propagation in solid materials is presented with consideration of the altered behavior in anisotropic and nonlinear elastic materials in comparison with isotropic and linear elastic materials. Some experimental results are described in which ultrasonic velocity and attenuation measurements give insight into materials microstructure and associated mechanical properties. Recent developments with laser beam non-contact generation and detection of ultrasound are presented. The results of several years of experimental measurements using high-power ultrasound are discussed, which provide substantial evidence of the inability of presently accepted theories to fully explain the interaction of ultrasound with solid materials. Finally, a special synchrotron X-ray topographic system is described which affords the possibility of observing direct interaction of ultrasonic waves with the microstructural features of real crystalline solid materials for the first time.

  5. NUCLEAR FUEL MATERIAL

    DOEpatents

    Goeddel, W.V.

    1962-06-26

    An improved method is given for making the carbides of nuclear fuel material. The metal of the fuel material, which may be a fissile and/or fertile material, is transformed into a silicide, after which the silicide is comminuted to the desired particle size. This silicide is then carburized at an elevated temperature, either above or below the melting point of the silicide, to produce an intimate mixture of the carbide of the fuel material and the carbide of silicon. This mixture of the fuel material carbide and the silicon carbide is relatively stable in the presence of moisture and does not exhibit the highly reactive surface condition which is observed with fuel material carbides made by most other known methods. (AEC)

  6. Benzimidazole Based Aerogel Materials

    NASA Technical Reports Server (NTRS)

    Rhine, Wendell E. (Inventor); Mihalcik, David (Inventor)

    2016-01-01

    The present invention provides aerogel materials based on imidazoles and polyimidazoles. The polyimidazole based aerogel materials can be thermally stable up to 500 C or more, and can be carbonized to produce a carbon aerogel having a char yield of 60% or more, specifically 70% or more. The present invention also provides methods of producing polyimidazole based aerogel materials by reacting at least one monomer in a suitable solvent to form a polybenzimidazole gel precursor solution, casting the polybenzimidazole gel precursor solution into a fiber reinforcement phase, allowing the at least one gel precursor in the precursor solution to transition into a gel material, and drying the gel materials to remove at least a portion of the solvent, to obtain an polybenzimidazole-based aerogel material.

  7. Characterization of Nanophase Materials

    NASA Astrophysics Data System (ADS)

    Wang, Zhong Lin

    2000-01-01

    Engineering of nanophase materials and devices is of vital interest in electronics, semiconductors and optics, catalysis, ceramics and magnetism. Research associated with nanoparticles has widely spread and diffused into every field of scientific research, forming a trend of nanocrystal engineered materials. The unique properties of nanophase materials are entirely determined by their atomic scale structures, particularly the structures of interfaces and surfaces. Development of nanotechnology involves several steps, of which characterization of nanoparticles is indespensable to understand the behavior and properties of nanoparticles, aiming at implementing nanotechnolgy, controlling their behavior and designing new nanomaterials systems with super performance. The book will focus on structural and property characterization of nanocrystals and their assemblies, with an emphasis on basic physical approach, detailed techniques, data interpretation and applications. Intended readers of this comprehensive reference work are advanced graduate students and researchers in the field, who are specialized in materials chemistry, materials physics and materials science.

  8. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2012-05-15

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  9. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.

    2010-07-13

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  10. Femtosecond laser materials processing

    SciTech Connect

    Stuart, B

    1998-08-05

    Femtosecond lasers enable materials processing of most any material with extremely high precision and negligible shock or thermal loading to the surrounding area. Applications ranging from drilling teeth to cutting explosives to precision cuts in composites are possible by using this technology. For material removal at reasonable rates, we have developed a fully computer-controlled 15-Watt average power, 100-fs laser machining system.

  11. Material for Fast Cutting

    NASA Technical Reports Server (NTRS)

    Perez, A.

    1986-01-01

    New material for cutting tools increases productivity of machining processes. Material, called Iscanite (or equivalent), based on silicon nitride contains more than 90 percent silicon. Combines impact resistance close to that of coated carbides with heat and wear resistance close to those of aluminum oxide ceramics. Material used for cutting on old or new machine tools and makes it possible to exploit fully power and speed of machine.

  12. Multilayer Insulation Material Guidelines

    NASA Technical Reports Server (NTRS)

    Finckenor, M. M.; Dooling, D.

    1999-01-01

    Multilayer Insulation Material Guidelines provides data on multilayer insulation materials used by previous spacecraft such as Spacelab and the Long-Duration Exposure Facility and outlines other concerns. The data presented in the document are presented for information only. They can be used as guidelines for multilayer insulation design for future spacecraft provided the thermal requirements of each new design and the environmental effects on these materials are taken into account.

  13. Infrared fiber optic materials

    NASA Technical Reports Server (NTRS)

    Feigelson, Robert S.

    1987-01-01

    The development of IR fiber optics for use in astronomical and other space applications is summarized. Candidate materials were sought for use in the 1 to 200 micron and the 200 to 1000 micron wavelength range. Synthesis and optical characterization were carried out on several of these materials in bulk form. And the fabrication of a few materials in single crystal fiber optic form were studied.

  14. Femtosecond laser materials processing

    SciTech Connect

    Stuart, B. C., LLNL

    1998-06-02

    Femtosecond lasers enable materials processing of most any material with extremely high precision and negligible shock or thermal loading to the surrounding area Applications ranging from drilling teeth to cutting explosives to making high-aspect ratio cuts in metals with no heat-affected zone are made possible by this technology For material removal at reasonable rates, we developed a fully computer-controlled 15-Watt average power, 100-fs laser machining system.

  15. ANS materials databook

    SciTech Connect

    Marchbanks, M.F.

    1995-08-01

    Technical development in the Advanced Neutron Source (ANS) project is dynamic, and a continuously updated information source is necessary to provide readily usable materials data to the designer, analyst, and materials engineer. The Advanced Neutron Source Materials Databook (AMBK) is being developed as a part of the Advanced Neutron Source Materials Information System (AMIS). Its purpose is to provide urgently needed data on a quick-turnaround support basis for those design applications whose schedules demand immediate estimates of material properties. In addition to the need for quick materials information, there is a need for consistent application of data throughout the ANS Program, especially where only limited data exist. The AMBK is being developed to fill this need as well. It is the forerunner to the Advanced Neutron Source Materials Handbook (AMHB). The AMHB, as reviewed and approved by the ANS review process, will serve as a common authoritative source of materials data in support of the ANS Project. It will furnish documented evidence of the materials data used in the design and construction of the ANS system and will serve as a quality record during any review process whose objective is to establish the safety level of the ANS complex. The information in the AMBK and AMHB is also provided in electronic form in a dial-up computer database known as the ANS Materials Database (AMDB). A single consensus source of materials information prepared and used by all national program participants has several advantages. Overlapping requirements and data needs of various sub-projects and subcontractors can be met by a single document which is continuously revised. Preliminary and final safety analysis reports, stress analysis reports, equipment specifications, materials service reports, and many other project-related documents can be substantially reduced in size and scope by appropriate reference to a single data source.

  16. Wear of engineering materials

    SciTech Connect

    Hawk, J.A.

    1998-12-31

    Nearly 60 papers discuss fundamental and applied research in the areas of wear, erosion and wear-corrosion of materials. Focus is on ceramics, ceramic and polymer-matrix composites, and coatings; the effect of sliding wear and wear-corrosion of materials in manufacturing processes, automobiles and bearings; and wear and erosion of materials used in fossil-fuel power plants, minerals processing and heavy manufacturing.

  17. Materials for Slack Diaphragms

    NASA Technical Reports Server (NTRS)

    Puschmann, Traute

    1940-01-01

    This report deals with systematic experiments carried out on five diaphragm materials with different pretreatment, for the purpose of ascertaining the suitability of such materials for slack diaphragms. The relationship of deflection and load, temperature and moisture, was recorded. Of the explored materials, synthetic leather, balloon cloth, goldbeaters skin, Igelit and Buna, synthetic leather treated with castor oil is the most suitable material for the small pressure range required. Balloon cloth is nearly as good, while goldbeaters skin, Igelit and Buna were found to be below the required standards.

  18. Fluorinated elastomeric materials

    DOEpatents

    Lagow, Richard J.; Dumitru, Earl T.

    1990-02-13

    This invention relates to a method of making perfluorinated elastomeric materials, and to materials made by such methods. In the full synthetic scheme, a partially fluorinated polymeric compound, with moieties to prevent crystallization, is created. It is then crosslinked to a desired degree, then perfluorinated. Various intermediate materials, such as partially fluorinated crosslinked polymers, have useful properties, and are or may become commercially available. One embodiment of this invention therefore relates to perfluorination of a selected partially fluorinated, crosslinked material, which is one step of the full synthetic scheme.

  19. Fluorinated elastomeric materials

    DOEpatents

    Lagow, Richard J.; Dumitru, Earl T.

    1986-11-04

    This invention relates to a method of making perfluorinated elastomeric materials, and to materials made by such methods. In the full synthetic scheme, a partially fluorinated polymeric compound, with moieties to prevent crystallization, is created. It is then crosslinked to a desired degree, then perfluorinated. Various intermediate materials, such as partially fluorinated crosslinked polymers, have useful properties, and are or may become commercially available. One embodiment of this invention therefore relates to perfluorination of a selected partially fluorinated, crosslinked material, which is one step of the full synthetic scheme.

  20. Material for radioactive protection

    DOEpatents

    Taylor, R.S.; Boyer, N.W.

    A boron containing burn resistant, low-level radiation protection material useful, for example, as a liner for radioactive waste disposal and storage, a component for neutron absorber, and a shield for a neutron source is described. The material is basically composed of borax in the range of 25 to 50%, coal tar in the range of 25 to 37.5%, with the remainder being an epoxy resin mix. A preferred composition is 50% borax, 25% coal tar and 25% epoxy resin. The material is not susceptible to burning and is about 1/5 the cost of existing radiation protection material utilized in similar applications.

  1. Ceramic breeder materials

    SciTech Connect

    Johnson, C.E.; Kummerer, K.R.; Roth, E.

    1987-01-01

    Ceramic materials are under investigation as potential breeder material in fusion reactors. This paper will review candidate materials with respect to fabrication routes and characterization, properties in as-fabricated and irradiated condition, and experimental results from laboratory and inpile investigations on tritium transport and release. Also discussed are the resources of beryllium, which is being considered as a neutron multiplier. The comparison of ceramic properties that is attempted here aims at the identification of the most-promising material for use in a tritium breeding blanket. 82 refs., 12 figs., 5 tabs.

  2. Materials Science Laboratory

    NASA Technical Reports Server (NTRS)

    Jackson, Dionne

    2005-01-01

    The NASA Materials Science Laboratory (MSL) provides science and engineering services to NASA and Contractor customers at KSC, including those working for the Space Shuttle. International Space Station. and Launch Services Programs. These services include: (1) Independent/unbiased failure analysis (2) Support to Accident/Mishap Investigation Boards (3) Materials testing and evaluation (4) Materials and Processes (M&P) engineering consultation (5) Metrology (6) Chemical analysis (including ID of unknown materials) (7) Mechanical design and fabrication We provide unique solutions to unusual and urgent problems associated with aerospace flight hardware, ground support equipment and related facilities.

  3. Thermoelectric materials having porosity

    DOEpatents

    Heremans, Joseph P.; Jaworski, Christopher M.; Jovovic, Vladimir; Harris, Fred

    2014-08-05

    A thermoelectric material and a method of making a thermoelectric material are provided. In certain embodiments, the thermoelectric material comprises at least 10 volume percent porosity. In some embodiments, the thermoelectric material has a zT greater than about 1.2 at a temperature of about 375 K. In some embodiments, the thermoelectric material comprises a topological thermoelectric material. In some embodiments, the thermoelectric material comprises a general composition of (Bi.sub.1-xSb.sub.x).sub.u(Te.sub.1-ySe.sub.y).sub.w, wherein 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 1.8.ltoreq.u.ltoreq.2.2, 2.8.ltoreq.w.ltoreq.3.2. In further embodiments, the thermoelectric material includes a compound having at least one group IV element and at least one group VI element. In certain embodiments, the method includes providing a powder comprising a thermoelectric composition, pressing the powder, and sintering the powder to form the thermoelectric material.

  4. The Materials Genome Project

    NASA Astrophysics Data System (ADS)

    Aourag, H.

    2008-09-01

    In the past, the search for new and improved materials was characterized mostly by the use of empirical, trial- and-error methods. This picture of materials science has been changing as the knowledge and understanding of fundamental processes governing a material's properties and performance (namely, composition, structure, history, and environment) have increased. In a number of cases, it is now possible to predict a material's properties before it has even been manufactured thus greatly reducing the time spent on testing and development. The objective of modern materials science is to tailor a material (starting with its chemical composition, constituent phases, and microstructure) in order to obtain a desired set of properties suitable for a given application. In the short term, the traditional "empirical" methods for developing new materials will be complemented to a greater degree by theoretical predictions. In some areas, computer simulation is already used by industry to weed out costly or improbable synthesis routes. Can novel materials with optimized properties be designed by computers? Advances in modelling methods at the atomic level coupled with rapid increases in computer capabilities over the last decade have led scientists to answer this question with a resounding "yes'. The ability to design new materials from quantum mechanical principles with computers is currently one of the fastest growing and most exciting areas of theoretical research in the world. The methods allow scientists to evaluate and prescreen new materials "in silico" (in vitro), rather than through time consuming experimentation. The Materials Genome Project is to pursue the theory of large scale modeling as well as powerful methods to construct new materials, with optimized properties. Indeed, it is the intimate synergy between our ability to predict accurately from quantum theory how atoms can be assembled to form new materials and our capacity to synthesize novel materials atom

  5. Mechanics of materials model

    NASA Technical Reports Server (NTRS)

    Meister, Jeffrey P.

    1987-01-01

    The Mechanics of Materials Model (MOMM) is a three-dimensional inelastic structural analysis code for use as an early design stage tool for hot section components. MOMM is a stiffness method finite element code that uses a network of beams to characterize component behavior. The MOMM contains three material models to account for inelastic material behavior. These include the simplified material model, which assumes a bilinear stress-strain response; the state-of-the-art model, which utilizes the classical elastic-plastic-creep strain decomposition; and Walker's viscoplastic model, which accounts for the interaction between creep and plasticity that occurs under cyclic loading conditions.

  6. Innovative Solar Optical Materials

    NASA Astrophysics Data System (ADS)

    Lampert, Carl M.

    1984-02-01

    A variety of optical coatings are discussed in the context of solar energy utilization. Well-known coatings such as transparent conductors (heat mirrors), selective absorbers, and reflective films are surveyed briefly. Emphasis is placed on the materials' limitations and on use of lesser-known optical coatings and materials. Physical and optical properties are detailed for protective antireflection films, cold mirrors, fluorescent concentrator materials, radiative cooling surfaces, and optical switching films including electrochromic, thermochromic, photochromic, and liquid crystal types. For many of these materials, research has only recently been considered, so various design and durability issues need to be addressed.

  7. Flexible Material Systems Testing

    NASA Technical Reports Server (NTRS)

    Lin, John K.; Shook, Lauren S.; Ware, Joanne S.; Welch, Joseph V.

    2010-01-01

    An experimental program has been undertaken to better characterize the stress-strain characteristics of flexible material systems to support a NASA ground test program for inflatable decelerator material technology. A goal of the current study is to investigate experimental methods for the characterization of coated woven material stiffness. This type of experimental mechanics data would eventually be used to define the material inputs of fluid-structure interaction simulation models. The test methodologies chosen for this stress-strain characterization are presented along with the experimental results.

  8. Charge Photogeneration Experiments and Theory in Aggregated Squaraine Donor Materials for Improved Organic Solar Cell Efficiencies

    NASA Astrophysics Data System (ADS)

    Spencer, Susan Demetra

    Fossil fuel consumption has a deleterious effect on humans, the economy, and the environment. Renewable energy technologies must be identified and commercialized as quickly as possible so that the transition to renewables can happen at a minimum of financial and societal cost. Organic photovoltaic cells offer an inexpensive and disruptive energy technology, if the scientific challenges of understanding charge photogeneration in a bulk heterojunction material can be overcome. At RIT, there is a strong focus on creating new materials that can both offer fundamentally important scientific results relating to quantum photophysics, and simultaneously assist in the development of strong candidates for future commercialized technology. In this presentation, the results of intensive materials characterization of a series of squaraine small molecule donors will be presented, as well as a full study of the fabrication and optimization required to achieve >4% photovoltaic cell efficiency. A relationship between the molecular structure of the squaraine and its ability to form nanoscale aggregates will be explored. Squaraine aggregation will be described as a unique optoelectronic probe of the structure of the bulk heterojunction. This relationship will then be utilized to explain changes in crystallinity that impact the overall performance of the devices. Finally, a predictive summary will be given for the future of donor material research at RIT.

  9. LDEF materials overview

    NASA Technical Reports Server (NTRS)

    Stein, Bland A.

    1993-01-01

    The flight and retrieval of the National Aeronautics and Space Administration's Long Duration Exposure Facility (LDEF) provided an opportunity for the study of the low-Earth orbit (LEO) environment and long-duration space environmental effects (SEE) on materials that is unparalleled in the history of the U.S. Space Program. The 5-year, 9-month flight of LDEF greatly enhanced the potential value of all materials on LDEF to the international SEE community, compared to that of the original 1-year flight plan. The remarkable flight attitude stability of LDEF enables specific analyses of individual and combined effects of LEO environmental parameters on identical materials on the same space vehicle. NASA recognized this potential by forming the LDEF Space Environmental Effects on Materials Special Investigation Group (MSIG) to address the greatly expanded materials and LEO space environment analysis opportunities available in the LDEF structure, experiment trays, and corollary measurements so that the combined value of all LDEF materials data to current and future space missions will be addressed and documented. An overview of the interim LDEF materials findings of the principal investigators and the Materials Special Investigation Group is provided. These revelations are based on observations of LEO environmental effects on materials made in space during LDEF retrieval and during LDEF tray deintegration at the Kennedy Space Center, and on findings of approximately 1.5 years of laboratory analyses of LDEF materials by the LDEF materials scientists. These findings were extensively reviewed and discussed at the MSIG-sponsored LDEF Materials Workshop '91. The results are presented in a format that categorizes the revelations as 'clear findings' or 'obscure preliminary findings' (and progress toward their resolution), plus resultant needs for new space materials developments and ground simulation testing/analytical modeling, in seven categories: materials

  10. Social network architecture and the maintenance of deleterious cultural traits

    PubMed Central

    Yeaman, Sam; Schick, Alana; Lehmann, Laurent

    2012-01-01

    How have changes in communications technology affected the way that misinformation spreads through a population and persists? To what extent do differences in the architecture of social networks affect the spread of misinformation, relative to the rates and rules by which individuals transmit or eliminate different pieces of information (cultural traits)? Here, we use analytical models and individual-based simulations to study how a ‘cultural load’ of misinformation can be maintained in a population under a balance between social transmission and selective elimination of cultural traits with low intrinsic value. While considerable research has explored how network architecture affects percolation processes, we find that the relative rates at which individuals transmit or eliminate traits can have much more profound impacts on the cultural load than differences in network architecture. In particular, the cultural load is insensitive to correlations between an individual's network degree and rate of elimination when these quantities vary among individuals. Taken together, these results suggest that changes in communications technology may have influenced cultural evolution more strongly through changes in the amount of information flow, rather than the details of who is connected to whom. PMID:22031730

  11. Deleterious effects of magnesium intoxication upon the domestic broiler chick

    SciTech Connect

    Lee, S.R.

    1984-01-01

    Dietary levels of 0.6 to 0.8% magnesium in a corn-soy basal were rachitogenic. These rickets appeared most like phosphorus deficiency. Bone Ca/P ratios were numerically quite low implying a lack of transformation from amorphous calcium phosphate to hydroxyapatite. Bone alkaline phosphatase activity was elevated. Additional dietary phosphorus ameliorated, but could not overcome the rachitogenic effects of magnesium. Tibial dyschondroplasia (TD), induced by elevated dietary P, was decreased by high levels of dietary Mg, but with no decrease in plasma phosphorus. Anticoccidial ionophores fed in conjunction with a moderate dietary challenge of Mg (0.48%) produced no clear changes in plasma calcium or Mg, but did interact to reduce body weight. The diarrhea caused by magnesium intoxication is not due to hyperosmotic loads of Mg per se. Rather, Cl was observed to be the major ionic constituent of the gut osmotic load implying different gut ionic fluxes in control versus magnesium intoxicated chicks. These data imply that the cathartic action of Mg is due to hypersecretion of the gut. Effects mediated or modified by the CNS changed in magnesium intoxicated chicks. Such chicks appeared cold and stayed near the heat. When startled, they exhibited extreme avoidance behavior and seizures similar to epilepsy and/or Cl deficiency. Brain tissue Mg content did not concomitantly increase. Whether these effects are due to central signals is unclear.

  12. Sildenafil citrate attenuates the deleterious effects of elevated ammonia.

    PubMed

    Arafa, Manar H; Atteia, Hebatallah H

    2013-07-01

    Ammonia is a bi-product of protein metabolism in the body. It is able to cross the blood-brain barrier and elevated ammonia levels are toxic to the brain. Rats with hyperammonemia showed impaired learning ability and impaired function of the glutamate-nitric oxide-cyclic guanosine monophosphate (glutamate-NO-cGMP) pathway in the brain. Chronic treatment with sildenafil restored learning ability. We therefore tested the hypothesis that sildenafil has a protective effect on the brains of hyperammonemic rats. Hyperammonemia was induced in male rats by daily intraperitoneal (i.p.) injection of ammonium chloride (100 mg/kg body weight) for 8 weeks. Sildenafil citrate was administered intraperitoneally (10 mg/kg body weight/3 days) for 8 weeks. Treatment with sildenafil resulted in a significant reduction in plasma liver enzymes, lipid profile as well as brain lipid peroxidation and caspase-3 mRNA. Meanwhile, plasma NO as well as cGMP, antioxidants and endothelial nitric oxide synthase (eNOS) gene expression were significantly elevated in the brains of hyperammonemic rats. Our results showed that sildenafil exerts a protective effect on the brain by reversing oxidative stress during hyperammonemia and this could be due to (i) cytoprotective, antioxidant and anti-apoptotic effects (ii) increasing cGMP and enhancing the proper metabolism of fats which could suppress oxygen radical generation and thus preventing oxidative damage in the brain. The exact protective mechanism of sildenafil has to be still investigated and further studies are warranted. Consequently, therapeutic modulation of the NO/cGMP pathway might have important clinical applications to improve brain functions in patients with hyperammonemia or clinical hepatic encephalopathy.

  13. Social network architecture and the maintenance of deleterious cultural traits.

    PubMed

    Yeaman, Sam; Schick, Alana; Lehmann, Laurent

    2012-05-07

    How have changes in communications technology affected the way that misinformation spreads through a population and persists? To what extent do differences in the architecture of social networks affect the spread of misinformation, relative to the rates and rules by which individuals transmit or eliminate different pieces of information (cultural traits)? Here, we use analytical models and individual-based simulations to study how a 'cultural load' of misinformation can be maintained in a population under a balance between social transmission and selective elimination of cultural traits with low intrinsic value. While considerable research has explored how network architecture affects percolation processes, we find that the relative rates at which individuals transmit or eliminate traits can have much more profound impacts on the cultural load than differences in network architecture. In particular, the cultural load is insensitive to correlations between an individual's network degree and rate of elimination when these quantities vary among individuals. Taken together, these results suggest that changes in communications technology may have influenced cultural evolution more strongly through changes in the amount of information flow, rather than the details of who is connected to whom.

  14. Temporal regularity in speech perception: Is regularity beneficial or deleterious?

    PubMed

    Geiser, Eveline; Shattuck-Hufnagel, Stefanie

    2012-04-01

    Speech rhythm has been proposed to be of crucial importance for correct speech perception and language learning. This study investigated the influence of speech rhythm in second language processing. German pseudo-sentences were presented to participants in two conditions: 'naturally regular speech rhythm' and an 'emphasized regular rhythm'. Nine expert English speakers with 3.5±1.6 years of German training repeated each sentence after hearing it once over headphones. Responses were transcribed using the International Phonetic Alphabet and analyzed for the number of correct, false and missing consonants as well as for consonant additions. The over-all number of correct reproductions of consonants did not differ between the two experimental conditions. However, speech rhythmicization significantly affected the serial position curve of correctly reproduced syllables. The results of this pilot study are consistent with the view that speech rhythm is important for speech perception.

  15. Gestational magnesium deficiency is deleterious to fetal outcome.

    PubMed

    Almonte, R A; Heath, D L; Whitehall, J; Russell, M J; Patole, S; Vink, R

    1999-07-01

    A number of recent epidemiological findings have implicated magnesium as being essential to fetal well-being. Few studies, however, have examined the relationship between maternal requirements for dietary magnesium and subsequent mortality and morbidity in offspring. The present study uses a rodent model of dietary-induced hypomagnesemia to investigate the effects of magnesium deficiency prior to and during gestation on neonatal morbidity and mortality. Magnesium deficiency during gestation significantly increased neonatal mortality and morbidity. Such increases were associated with a reduced free magnesium concentration in both maternal and offspring blood and an increased incidence of periventricular hemorrhage and edema in newborn pups as observed by magnetic resonance imaging and histology. Animals fed a magnesium-deficient diet before mating but given magnesium supplementation during gestation did not demonstrate a significant change in neonatal mortality and morbidity when compared to control animals. The significant improvement in fetal outcome with dietary magnesium supports the concept of magnesium supplementation during pregnancy.

  16. Bombardment of the Hadean Earth: wholesome or deleterious?

    PubMed

    Ryder, Graham

    2003-01-01

    Graham Ryder died in January 2002 at the age of 53. He was a Staff Scientist at the Lunar and Planetary Science Institute in Houston, TX for most of his professional life, studying lunar petrology and planetary impacts. For many years he was the senior editor of the Proceedings of the Lunar and Planetary Science Conference, and he was the senior editor of Geological Society of America Special Paper 307, The Cretaceous-Tertiary Event and Other Catastrophes in Earth History. He was the major advocate for the 3.8 Ga lunar impact cataclysm and was just beginning to publish on correlations of the early lunar impact record to that of the other inner planets at the time of his death. Graham's abstract to the Rubey Colloquium was never presented. Although Graham made many of the points in this abstract to lunar science audiences, he certainly would have wanted these views to be shared with the Astrobiology community. We have taken the liberty of publishing this abstract with the Rubey proceedings, with only a few minor revisions to include reference to some recently published papers. These revisions were recommended by Gary R. Byerly, who reviewed this abstract for publication.

  17. Deleterious actions of gossypol on bovine spermatozoa, oocytes, and embryos.

    PubMed

    Brocas, C; Rivera, R M; Paula-Lopes, F F; McDowell, L R; Calhoun, M C; Staples, C R; Wilkinson, N S; Boning, A J; Chenoweth, P J; Hansen, P J

    1997-10-01

    Gossypol (50 and 100 micrograms/ml) decreased the percentage of sperm that completed the swim-up procedure. This effect was not blocked by glutathione monoethyl ester. Cleavage rates were not different between oocytes inseminated with gossypol-treated spermatozoa (10 or 50 micrograms/ml) and oocytes inseminated with control spermatozoa. Development to the blastocyst stage at Day 7 after insemination was reduced when spermatozoa treated with 50 micrograms/ml gossypol were used for fertilization. Gossypol toxicity was evident in cows fed cottonseed meal because erythrocyte fragility was greater than for control cows. However, there were no differences between cottonseed meal and control groups in number of oocytes collected per cow, cleavage rate after in vitro maturation and fertilization, or the proportion of oocytes or embryos that developed to blastocysts. Similarly, exposure of oocytes to 2.5-10 micrograms/ml gossypol during in vitro maturation did not affect cleavage rates or subsequent development. In contrast, addition of 10 micrograms/ml gossypol to embryos reduced cleavage rate. Moreover, development of cleaved embryos was reduced by culture with 5 or 10 micrograms/ml gossypol and tended to be reduced by 2.5 micrograms/ml gossypol. In conclusion, bovine gametes are resistant to gossypol at concentrations similar to those in blood of cows fed cottonseed meal. In contrast, the developing embryo is sensitive to gossypol.

  18. Escaping Deleterious Immune Response in Their Hosts: Lessons from Trypanosomatids

    PubMed Central

    Geiger, Anne; Bossard, Géraldine; Sereno, Denis; Pissarra, Joana; Lemesre, Jean-Loup; Vincendeau, Philippe; Holzmuller, Philippe

    2016-01-01

    The Trypanosomatidae family includes the genera Trypanosoma and Leishmania, protozoan parasites displaying complex digenetic life cycles requiring a vertebrate host and an insect vector. Trypanosoma brucei gambiense, Trypanosoma cruzi, and Leishmania spp. are important human pathogens causing human African trypanosomiasis (HAT or sleeping sickness), Chagas’ disease, and various clinical forms of Leishmaniasis, respectively. They are transmitted to humans by tsetse flies, triatomine bugs, or sandflies, and affect millions of people worldwide. In humans, extracellular African trypanosomes (T. brucei) evade the hosts’ immune defenses, allowing their transmission to the next host, via the tsetse vector. By contrast, T. cruzi and Leishmania sp. have developed a complex intracellular lifestyle, also preventing several mechanisms to circumvent the host’s immune response. This review seeks to set out the immune evasion strategies developed by the different trypanosomatids resulting from parasite–host interactions and will focus on: clinical and epidemiological importance of diseases; life cycles: parasites–hosts–vectors; innate immunity: key steps for trypanosomatids in invading hosts; deregulation of antigen-presenting cells; disruption of efficient specific immunity; and the immune responses used for parasite proliferation. PMID:27303406

  19. Nanoprobes, nanostructured materials and solid state materials

    NASA Astrophysics Data System (ADS)

    Yin, Houping

    2005-07-01

    Novel templates have been developed to prepare nanostructured porous materials through nonsurfactant templated pathway. And new applications of these materials, such as drug delivery and molecular imprinting, have been explored. The relationship between template content and pore structure has been investigated. The composition and pore structures were studied in detail using IR, TGA, SEM, TEM, BET and XRD. The obtained mesoporous materials have tunable diameters in the range of 2--12 nm. Due to the many advantages of this nonsurfactant templated pathway, such as environment friendly and biocompatibility, controlled release of antibiotics in the nanoporous materials were studied. The in vitro release properties were found to depend on the silica structures which were well tuned by varying the template content. A controlled long-term release pattern of vancomycin was achieved when the template content was 30 wt% or lower. Nanoscale electrochemical probes with dimensions as small as 50 nm in diameter and 1--2 mum in length were fabricated using electron beam deposition on the apex of conventional micron size electrodes. The electroactive region was limited to the extreme tip of the nanoprobe by coating with an insulating polymer and re-opening of the coating at the extreme tip. The novel nanoelectrodes thus prepared were employed to probe neurons in mouse brain slice and the results suggest that the nanoprobes were capable of recording neuronal excitatory postsynaptic potential signals. Interesting solid state chemistry was found in oxygenated iron phthalocyanine. Their Mossbauer spectra show the formation of four oxygenated species apart from the unoxygenated parent compound. The oxygen-bridged compounds formed in the solid matrix bear no resemblance to the one formed by solution chemistry. Tentative assignment of species has been made with the help of Mossbauer and IR spectroscopy. An effort to modify aniline trimer for potential nanoelectronics applications and to

  20. Materials characterization on efforts for ablative materials

    NASA Technical Reports Server (NTRS)

    Tytula, Thomas P.; Schad, Kristin C.; Swann, Myles H.

    1992-01-01

    Experimental efforts to develop a new procedure to measure char depth in carbon phenolic nozzle material are described. Using a Shor Type D Durometer, hardness profiles were mapped across post fired sample blocks and specimens from a fired rocket nozzle. Linear regression was used to estimate the char depth. Results are compared to those obtained from computed tomography in a comparative experiment. There was no significant difference in the depth estimates obtained by the two methods.

  1. 75 FR 30863 - Nixon Presidential Historical Materials: Opening of Materials

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... RECORDS ADMINISTRATION Nixon Presidential Historical Materials: Opening of Materials AGENCY: National Archives and Records Administration. ACTION: Notice of opening of additional materials. SUMMARY: This notice announces the opening of additional Nixon Presidential Historical Materials by the Richard...

  2. 76 FR 62856 - Nixon Presidential Historical Materials: Opening of Materials

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-11

    ... RECORDS ADMINISTRATION Nixon Presidential Historical Materials: Opening of Materials AGENCY: National Archives and Records Administration. ACTION: Notice of opening of additional materials. SUMMARY: This notice announces the opening of Nixon Presidential Historical Materials by the Richard Nixon...

  3. 76 FR 35918 - Nixon Presidential Historical Materials; Opening of Materials

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... Materials; Opening of Materials AGENCY: National Archives and Records Administration. ACTION: Notice of Opening of Additional Materials. SUMMARY: This notice announces the opening of additional Nixon Presidential Historical Materials by the Richard Nixon Presidential Library and Museum, a division of...

  4. Materials Science and Technology.

    ERIC Educational Resources Information Center

    Piippo, Steven W.

    1989-01-01

    Describes a materials science and technology course for high school students, which combines chemistry, physics, engineering, math, technology education, and crafts to introduce students to the atomic make-up and physical properties of materials and to apply this knowledge in creative activities. (SK)

  5. Social character of materialism.

    PubMed

    Chatterjee, A; Hunt, J M; Kernan, J B

    2000-06-01

    Scores for 170 undergraduates on Richins and Dawson's Materialism scale were correlated with scores on Kassarjian's Social Preference Scale, designed to measure individuals' character structure. A correlation of .26 between materialism and other-directed social character suggested that an externally oriented reference system guides materialists' perceptions, judgments, acquisitions, and possessions.

  6. Material Writer's Guide.

    ERIC Educational Resources Information Center

    Byrd, Patricia, Ed.

    This guide is a collection of essays on the writing of English-as-a-Second-Language (ESL) textbooks and other instructional materials. Articles include: "Writing and Publishing Textbooks (Patricia Byrd); "The Craft of Materials Writing" (Fraida Dubin); "Considering Culture: Guidelines for ESL/EFL Textbook Writers" (Gayle Nelson); "Issues in the…

  7. Gravitation in Material Media

    ERIC Educational Resources Information Center

    Ridgely, Charles T.

    2011-01-01

    When two gravitating bodies reside in a material medium, Newton's law of universal gravitation must be modified to account for the presence of the medium. A modified expression of Newton's law is known in the literature, but lacks a clear connection with existing gravitational theory. Newton's law in the presence of a homogeneous material medium…

  8. Marine Education Materials System.

    ERIC Educational Resources Information Center

    Gammisch, Sue; Gray, Kevin

    1980-01-01

    Described is a marine education materials clearinghouse, the Marine Education Materials System (MEMS). MEMS classifies marine education documents and reproduces them on microfiche for distribution. There are 25 distribution centers, each of which has a collection of documents and provides assistance on a request basis to teachers. (Author/DS)

  9. Packaging Your Training Materials

    ERIC Educational Resources Information Center

    Espeland, Pamela

    1977-01-01

    The types of packaging and packaging materials to use for training materials should be determined during the planning of the training programs, according to the packaging market. Five steps to follow in shopping for packaging are presented, along with a list of packaging manufacturers. (MF)

  10. Scintillator materials for calorimetry

    SciTech Connect

    Weber, M.J.

    1994-09-01

    Requirements for fast, dense scintillator materials for calorimetry in high energy physics and approaches to satisfying these requirements are reviewed with respect to possible hosts and luminescent species. Special attention is given to cerium-activated crystals, core-valence luminescence, and glass scintillators. The present state of the art, limitations, and suggestions for possible new scintillator materials are presented.

  11. Carbon Materials Research

    DTIC Science & Technology

    2005-07-14

    behavior, interfacial energies, and surface molecular orientation (surface anchoring states) for mesophase pitch on carbon fibers and other...Mochida (2) extended it to the production of mesophase pitch by dramatically raising Distribution A: Approved for public release; distribution...involved i.e. it is a very insoluble material. Mochida, however, recognized that this material was liquid-crystalline mesophase pitch , which was

  12. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R. G.; Wiberley, S. E.

    1985-01-01

    Various topics relating to composite structural materials for use in aircraft structures are discussed. The mechanical properties of high performance carbon fibers, carbon fiber-epoxy interface bonds, composite fractures, residual stress in high modulus and high strength carbon fibers, fatigue in composite materials, and the mechanical properties of polymeric matrix composite laminates are among the topics discussed.

  13. NBS: Materials measurements

    NASA Technical Reports Server (NTRS)

    Manning, J. R.

    1981-01-01

    Measurement of materials properties and thermophysical properties is described. The topics discussed are: surface tensions and their variations with temperature and impurities; convection during unidirectional solidification: measurement of high temperature thermophysical properties of tungsten liquid and solid; thermodynamic properties of refractory materials at high temperatures; and experimental and theoretical studies in wetting and multilayer adsorption.

  14. Strongly correlated materials.

    PubMed

    Morosan, Emilia; Natelson, Douglas; Nevidomskyy, Andriy H; Si, Qimiao

    2012-09-18

    Strongly correlated materials are profoundly affected by the repulsive electron-electron interaction. This stands in contrast to many commonly used materials such as silicon and aluminum, whose properties are comparatively unaffected by the Coulomb repulsion. Correlated materials often have remarkable properties and transitions between distinct, competing phases with dramatically different electronic and magnetic orders. These rich phenomena are fascinating from the basic science perspective and offer possibilities for technological applications. This article looks at these materials through the lens of research performed at Rice University. Topics examined include: Quantum phase transitions and quantum criticality in "heavy fermion" materials and the iron pnictide high temperature superconductors; computational ab initio methods to examine strongly correlated materials and their interface with analytical theory techniques; layered dichalcogenides as example correlated materials with rich phases (charge density waves, superconductivity, hard ferromagnetism) that may be tuned by composition, pressure, and magnetic field; and nanostructure methods applied to the correlated oxides VO₂ and Fe₃O₄, where metal-insulator transitions can be manipulated by doping at the nanoscale or driving the system out of equilibrium. We conclude with a discussion of the exciting prospects for this class of materials.

  15. Hydrocarbonaceous material upgrading method

    DOEpatents

    Brecher, Lee E.; Mones, Charles G.; Guffey, Frank D.

    2015-06-02

    A hydrocarbonaceous material upgrading method may involve a novel combination of heating, vaporizing and chemically reacting hydrocarbonaceous feedstock that is substantially unpumpable at pipeline conditions, and condensation of vapors yielded thereby, in order to upgrade that feedstock to a hydrocarbonaceous material condensate that meets crude oil pipeline specification.

  16. MATERIAL TRACKING USING LANMAS

    SciTech Connect

    Armstrong, F.

    2010-06-07

    LANMAS is a transaction-based nuclear material accountability software product developed to replace outdated and legacy accountability systems throughout the DOE. The core underlying purpose of LANMAS is to track nuclear materials inventory and report transactions (movement, mixing, splitting, decay, etc.) to the Nuclear Materials Management and Safeguards System (NMMSS). While LANMAS performs those functions well, there are many additional functions provided by the software product. As a material is received onto a site or created at a site, its entire lifecycle can be tracked in LANMAS complete to its termination of safeguards. There are separate functions to track material movements between and within material balance areas (MBAs). The level of detail for movements within a MBA is configurable by each site and can be as high as a site designation or as detailed as building/room/rack/row/position. Functionality exists to track the processing of materials, either as individual items or by modeling a bulk process as an individual item to track inputs and outputs from the process. In cases where sites have specialized needs, the system is designed to be flexible so that site specific functionality can be integrated into the product. This paper will demonstrate how the software can be used to input material into an account and track it to its termination of safeguards.

  17. Selection of Music Materials

    ERIC Educational Resources Information Center

    Luttmann, Stephen

    2004-01-01

    The conscientious selection of music materials requires an understanding of the needs of the public being served at least as much as it requires subject competence on the part of the selector. Online and print resources are available to aid in the selection of music materials in all formats, the most important of which are books, scores, audio and…

  18. Materials Science and Engineering

    SciTech Connect

    Lesuer, D.R.

    1993-03-01

    Five papers are included: processing/characterization of laminated metal composites, casting process modeling, characterizing the failure of composite materials, fiber-optic Raman spectroscopy for cure monitoring of advanced polymer composites, and modeling superplastic materials. The papers are processed separately for the data base.

  19. Thermal Protection Materials

    NASA Technical Reports Server (NTRS)

    Johnson, Sylvia M.

    2011-01-01

    Thermal protection materials and systems (TPS) are required to protect a vehicle returning from space or entering an atmosphere. The selection of the material depends on the heat flux, heat load, pressure, and shear and other mechanical loads imposed on the material, which are in turn determined by the vehicle configuration and size, location on the vehicle, speed, a trajectory, and the atmosphere. In all cases the goal is to use a material that is both reliable and efficient for the application. Reliable materials are well understood and have sufficient test data under the appropriate conditions to provide confidence in their performance. Efficiency relates to the behavior of a material under the specific conditions that it encounters TPS that performs very well at high heat fluxes may not be efficient at lower heat fluxes. Mass of the TPS is a critical element of efficiency. This talk will review the major classes of TPS, reusable or insulating materials and ablators. Ultra high temperature ceramics for sharp leading edges will also be reviewed. The talk will focus on the properties and behavior of these materials.

  20. Materials inventory management manual

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This NASA Materials Inventory Management Manual (NHB 4100.1) is issued pursuant to Section 203(c)(1) of the National Aeronautics and Space Act of 1958 (42 USC 2473). It sets forth policy, performance standards, and procedures governing the acquisition, management and use of materials. This Manual is effective upon receipt.

  1. Impacted material placement plans

    SciTech Connect

    Hickey, M.J.

    1997-01-29

    Impacted material placement plans (IMPP) are documents identifying the essential elements in placing remediation wastes into disposal facilities. Remediation wastes or impacted material(s) are those components used in the construction of the disposal facility exclusive of the liners and caps. The components might include soils, concrete, rubble, debris, and other regulatory approved materials. The IMPP provides the details necessary for interested parties to understand the management and construction practices at the disposal facility. The IMPP should identify the regulatory requirements from applicable DOE Orders, the ROD(s) (where a part of a CERCLA remedy), closure plans, or any other relevant agreements or regulations. Also, how the impacted material will be tracked should be described. Finally, detailed descriptions of what will be placed and how it will be placed should be included. The placement of impacted material into approved on-site disposal facilities (OSDF) is an integral part of gaining regulatory approval. To obtain this approval, a detailed plan (Impacted Material Placement Plan [IMPP]) was developed for the Fernald OSDF. The IMPP provides detailed information for the DOE, site generators, the stakeholders, regulatory community, and the construction subcontractor placing various types of impacted material within the disposal facility.

  2. MATERIALS FOR MODERNIZATION.

    ERIC Educational Resources Information Center

    JACKSON, R. GRAHAM

    CHOICES AND ISSUES IN SELECTING MATERIALS FOR MODERNIZATION OF SCHOOL BUILDINGS ARE DISCUSSED IN THIS REPORT. BACKGROUND INFORMATION IS INTRODUCED IN TERMS OF REASONS FOR ABANDONMENT, THE CAUSES AND EFFECTS OF SCHOOL BUILDING OBSOLESCENCE, AND PROBLEMS IN THE MODERNIZATION PROCESS. INTERIOR PARTITIONS ARE DISCUSSED IN TERMS OF BUILDING MATERIALS,…

  3. Millwright Instructional Materials.

    ERIC Educational Resources Information Center

    Hendrix, Laborn J.; Pierce, Greg

    This manual contains instructional materials for use in training millwrights working in industrial and commercial construction sites. Intended as an innovative complement to on-the-job training in construction, the material is written in terms of student performance using behavioral objectives and measured by criterion-referenced evaluation…

  4. Supramolecular biofunctional materials.

    PubMed

    Zhou, Jie; Li, Jie; Du, Xuewen; Xu, Bing

    2017-06-01

    This review discusses supramolecular biofunctional materials, a novel class of biomaterials formed by small molecules that are held together via noncovalent interactions. The complexity of biology and relevant biomedical problems not only inspire, but also demand effective molecular design for functional materials. Supramolecular biofunctional materials offer (almost) unlimited possibilities and opportunities to address challenging biomedical problems. Rational molecular design of supramolecular biofunctional materials exploit powerful and versatile noncovalent interactions, which offer many advantages, such as responsiveness, reversibility, tunability, biomimicry, modularity, predictability, and, most importantly, adaptiveness. In this review, besides elaborating on the merits of supramolecular biofunctional materials (mainly in the form of hydrogels and/or nanoscale assemblies) resulting from noncovalent interactions, we also discuss the advantages of small peptides as a prevalent molecular platform to generate a wide range of supramolecular biofunctional materials for the applications in drug delivery, tissue engineering, immunology, cancer therapy, fluorescent imaging, and stem cell regulation. This review aims to provide a brief synopsis of recent achievements at the intersection of supramolecular chemistry and biomedical science in hope of contributing to the multidisciplinary research on supramolecular biofunctional materials for a wide range of applications. We envision that supramolecular biofunctional materials will contribute to the development of new therapies that will ultimately lead to a paradigm shift for developing next generation biomaterials for medicine.

  5. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Wiberley, S. E.

    1978-01-01

    The purpose of the RPI composites program is to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, reliability and life prediction. Concommitant goals are to educate engineers to design and use composite materials as normal or conventional materials. A multifaceted program was instituted to achieve these objectives.

  6. Environmental materials and interfaces

    SciTech Connect

    Not Available

    1991-11-01

    A workshop that explored materials and interfaces research needs relevant to national environmental concerns was conducted at Pacific Northwest Laboratory. The purposes of the workshop were to refine the scientific research directions being planned for the Materials and Interface Program in the Molecular Science Research Center (MSRC) and further define the research and user equipment to the included as part of the proposed Environmental and Molecular Science Laboratory (EMSL). Three plenary information sessions served to outline the background, objectives, and status of the MSRC and EMSL initiatives; selected specific areas with environmentally related materials; and the status of capabilities and facilities planned for the EMSL. Attention was directed to four areas where materials and interface science can have a significant impact on prevention and remediation of environmental problems: in situ detection and characterization of hazardous wastes (sensors), minimization of hazardous waste (separation membranes, ion exchange materials, catalysts), waste containment (encapsulation and barrier materials), and fundamental understanding of contaminant transport mechanisms. During all other sessions, the participants were divided into three working groups for detailed discussion and the preparation of a written report. The working groups focused on the areas of interface structure and chemistry, materials and interface stability, and materials synthesis. These recommendations and suggestions for needed research will be useful for other researchers in proposing projects and for suggesting collaborative work with MSRC researchers. 1 fig.

  7. Smart materials in dentistry.

    PubMed

    McCabe, J F; Yan, Z; Al Naimi, O T; Mahmoud, G; Rolland, S L

    2011-06-01

    Most dental materials are designed to have a relatively 'neutral' existence in the mouth. It is considered that if they are 'passive' and do not react with the oral environment they will be more stable and have a greater durability. At the same time, it is hoped that our materials will be well accepted and will cause neither harm nor injury. This is an entirely negative approach to material tolerance and biocompatibility and hides the possibility that some positive gains can be achieved by using materials which behave in a more dynamic fashion in the environment in which they are placed. An example of materials which have potential for 'dynamic' behaviour exists with structures which are partly water-based or have phases or zones with significant water content and for which the water within the material can react to changes in the ambient conditions. Such materials may even be said to have the potential for 'smart' behaviour, i.e. they can react to changes in the environment to bring about advantageous changes in properties, either within the material itself or in the material-tooth complex. The controlled movement of water or aqueous media through the material may cause changes in dimensions, may be the carrier for various dissolved species, and may influence the potential for the formation of biofilms at the surface. Some of these issues may be closely interrelated. Clearly, materials which do not have the capacity for water transport or storage do not have the potential for this sort of behaviour. Some materials which are normally resistant to the healthy oral environment can undergo controlled degradation at low pH in order to release ions which may prove beneficial or protective. It is doubtful whether such behaviour should be classified as 'smart' because the material cannot readily return to its original condition when the stimulus is removed. Other materials, such as certain alloys, having no means of transporting water through their structure, can display

  8. Fingerprinting of Materials

    NASA Technical Reports Server (NTRS)

    Workman, Gary L

    1992-01-01

    Recent issues emerging in our fiscal and ecological environments have promulgated that federal agencies shall promote activities which respond to the improvement of both. In response to these developments, the National Aeronautics and Space Administration (NASA) has undertaken an innovative approach to improve the control of materials used in all NASA manufacturing activities. In concert with this goal, NASA is requiring that its contractors and their sub-contractors perform a more intensive consolidation of technologies that can provide an accounting of materials, which includes in-coming materials, materials in process, end-products and waste materials. The purpose of this handbook is to provide guidelines to NASA and its contractor personnel for the planning and implementation of chemical fingerprinting programs and to illustrate the chemical and statistical fundamentals needed for successful use of chemical fingerprinting.

  9. Material-based Stratification

    SciTech Connect

    MacQueen, D H

    2007-05-31

    A simple probability model was applied to detection sampling in a room or space in which different surface materials are present. The model assesses the overall detection capability when the sampling and analytical methods have different performance properties for the different materials. The results suggest that some common sampling strategies may not be ideal. In particular: (1) In a single room or area that includes different surface types with different detection properties, do not use a single sampling grid with a common spacing throughout. (2) If it is known or strongly suspected that one material has better detection properties than the other, place all samples on that material. (3) When it is completely unknown which material has the better detection properties, allocate the samples equally between them.

  10. Extraterrestrial materials processing

    NASA Technical Reports Server (NTRS)

    Steurer, W. H.

    1982-01-01

    The first year results of a multi-year study of processing extraterrestrial materials for use in space are summarized. Theoretically, there are potential major advantages to be derived from the use of such materials for future space endeavors. The types of known or postulated starting raw materials are described including silicate-rich mixed oxides on the Moon, some asteroids and Mars; free metals in some asteroids and in small quantities in the lunar soil; and probably volatiles like water and CO2 on Mars and some asteroids. Candidate processes for space materials are likely to be significantly different from their terrestrial counterparts largely because of: absence of atmosphere; lack of of readily available working fluids; low- or micro-gravity; no carbon-based fuels; readily available solar energy; and severe constraints on manned intervention. The extraction of metals and oxygen from lunar material by magma electrolysis or by vapor/ion phase separation appears practical.

  11. Materials of Gasification

    SciTech Connect

    2005-09-15

    The objective of this project was to accumulate and establish a database of construction materials, coatings, refractory liners, and transitional materials that are appropriate for the hardware and scale-up facilities for atmospheric biomass and coal gasification processes. Cost, fabricability, survivability, contamination, modes of corrosion, failure modes, operational temperatures, strength, and compatibility are all areas of materials science for which relevant data would be appropriate. The goal will be an established expertise of materials for the fossil energy area within WRI. This would be an effort to narrow down the overwhelming array of materials information sources to the relevant set which provides current and accurate data for materials selection for fossil fuels processing plant. A significant amount of reference material on materials has been located, examined and compiled. The report that describes these resources is well under way. The reference material is in many forms including texts, periodicals, websites, software and expert systems. The most important part of the labor is to refine the vast array of available resources to information appropriate in content, size and reliability for the tasks conducted by WRI and its clients within the energy field. A significant has been made to collate and capture the best and most up to date references. The resources of the University of Wyoming have been used extensively as a local and assessable location of information. As such, the distribution of materials within the UW library has been added as a portion of the growing document. Literature from recent journals has been combed for all pertinent references to high temperature energy based applications. Several software packages have been examined for relevance and usefulness towards applications in coal gasification and coal fired plant. Collation of the many located resources has been ongoing. Some web-based resources have been examined.

  12. Materials Research Capabilities

    NASA Technical Reports Server (NTRS)

    Stofan, Andrew J.

    1986-01-01

    Lewis Research Center, in partnership with U.S. industry and academia, has long been a major force in developing advanced aerospace propulsion and power systems. One key aspect that made many of these systems possible has been the availability of high-performance, reliable, and long-life materials. To assure a continuing flow of new materials and processing concepts, basic understanding to guide such innovation, and technological support for development of major NASA systems, Lewis has supported a strong in-house materials research activity. Our researchers have discovered new alloys, polymers, metallic composites, ceramics, coatings, processing techniques, etc., which are now also in use by U.S. industry. This brochure highlights selected past accomplishments of our materials research and technology staff. It also provides many examples of the facilities available with which we can conduct materials research. The nation is now beginning to consider integrating technology for high-performance supersonic/hypersonic aircraft, nuclear space power systems, a space station, and new research areas such as materials processing in space. As we proceed, I am confident that our materials research staff will continue to provide important contributions which will help our nation maintain a strong technology position in these areas of growing world competition. Lewis Research Center, in partnership with U.S. industry and academia, has long been a major force in developing advanced aerospace propulsion and power systems. One key aspect that made many of these systems possible has been the availability of high-performance, reliable, and long-life materials. To assure a continuing flow of new materials and processing concepts, basic understanding to guide such innovation, and technological support for development of major NASA systems, Lewis has supported a strong in-house materials research activity. Our researchers have discovered new alloys, polymers, metallic composites

  13. Mitigating the Effects of the Space Radiation Environment: A Novel Approach of Using Graded-Z Materials

    NASA Technical Reports Server (NTRS)

    Atwell, William; Rojdev, Kristina; Aghara, Sukesh; Sriprisan, Sirikul

    2013-01-01

    In this paper we present a novel space radiation shielding approach using various material lay-ups, called "Graded-Z" shielding, which could optimize cost, weight, and safety while mitigating the radiation exposures from the trapped radiation and solar proton environments, as well as the galactic cosmic radiation (GCR) environment, to humans and electronics. In addition, a validation and verification (V&V) was performed using two different high energy particle transport/dose codes (MCNPX & HZETRN). Inherently, we know that materials having high-hydrogen content are very good space radiation shielding materials. Graded-Z material lay-ups are very good trapped electron mitigators for medium earth orbit (MEO) and geostationary earth orbit (GEO). In addition, secondary particles, namely neutrons, are produced as the primary particles penetrate a spacecraft, which can have deleterious effects to both humans and electronics. The use of "dopants," such as beryllium, boron, and lithium, impregnated in other shielding materials provides a means of absorbing the secondary neutrons. Several examples of optimized Graded-Z shielding layups that include the use of composite materials are presented and discussed in detail. This parametric shielding study is an extension of some earlier pioneering work we (William Atwell and Kristina Rojdev) performed in 20041 and 20092.

  14. Materials at LANL

    SciTech Connect

    Taylor, Antoinette J

    2010-01-01

    Exploring the physics, chemistry, and metallurgy of materials has been a primary focus of Los Alamos National Laboratory since its inception. In the early 1940s, very little was known or understood about plutonium, uranium, or their alloys. In addition, several new ionic, polymeric, and energetic materials with unique properties were needed in the development of nuclear weapons. As the Laboratory has evolved, and as missions in threat reduction, defense, energy, and meeting other emerging national challenges have been added, the role of materials science has expanded with the need for continued improvement in our understanding of the structure and properties of materials and in our ability to synthesize and process materials with unique characteristics. Materials science and engineering continues to be central to this Laboratory's success, and the materials capability truly spans the entire laboratory - touching upon numerous divisions and directorates and estimated to include >1/3 of the lab's technical staff. In 2006, Los Alamos and LANS LLC began to redefine our future, building upon the laboratory's established strengths and promoted by strongly interdependent science, technology and engineering capabilities. Eight Grand Challenges for Science were set forth as a technical framework for bridging across capabilities. Two of these grand challenges, Fundamental Understanding of Materials and Superconductivity and Actinide Science. were clearly materials-centric and were led out of our organizations. The complexity of these scientific thrusts was fleshed out through workshops involving cross-disciplinary teams. These teams refined the grand challenge concepts into actionable descriptions to be used as guidance for decisions like our LDRD strategic investment strategies and as the organizing basis for our external review process. In 2008, the Laboratory published 'Building the Future of Los Alamos. The Premier National Security Science Laboratory,' LA-UR-08

  15. NSUF Irradiated Materials Library

    SciTech Connect

    Cole, James Irvin

    2015-09-01

    The Nuclear Science User Facilities has been in the process of establishing an innovative Irradiated Materials Library concept for maximizing the value of previous and on-going materials and nuclear fuels irradiation test campaigns, including utilization of real-world components retrieved from current and decommissioned reactors. When the ATR national scientific user facility was established in 2007 one of the goals of the program was to establish a library of irradiated samples for users to access and conduct research through competitively reviewed proposal process. As part of the initial effort, staff at the user facility identified legacy materials from previous programs that are still being stored in laboratories and hot-cell facilities at the INL. In addition other materials of interest were identified that are being stored outside the INL that the current owners have volunteered to enter into the library. Finally, over the course of the last several years, the ATR NSUF has irradiated more than 3500 specimens as part of NSUF competitively awarded research projects. The Logistics of managing this large inventory of highly radioactive poses unique challenges. This document will describe materials in the library, outline the policy for accessing these materials and put forth a strategy for making new additions to the library as well as establishing guidelines for minimum pedigree needed to be included in the library to limit the amount of material stored indefinitely without identified value.

  16. Bioinspired structural materials

    NASA Astrophysics Data System (ADS)

    Wegst, Ulrike G. K.; Bai, Hao; Saiz, Eduardo; Tomsia, Antoni P.; Ritchie, Robert O.

    2015-01-01

    Natural structural materials are built at ambient temperature from a fairly limited selection of components. They usually comprise hard and soft phases arranged in complex hierarchical architectures, with characteristic dimensions spanning from the nanoscale to the macroscale. The resulting materials are lightweight and often display unique combinations of strength and toughness, but have proven difficult to mimic synthetically. Here, we review the common design motifs of a range of natural structural materials, and discuss the difficulties associated with the design and fabrication of synthetic structures that mimic the structural and mechanical characteristics of their natural counterparts.

  17. Bioinspired structural materials.

    PubMed

    Wegst, Ulrike G K; Bai, Hao; Saiz, Eduardo; Tomsia, Antoni P; Ritchie, Robert O

    2015-01-01

    Natural structural materials are built at ambient temperature from a fairly limited selection of components. They usually comprise hard and soft phases arranged in complex hierarchical architectures, with characteristic dimensions spanning from the nanoscale to the macroscale. The resulting materials are lightweight and often display unique combinations of strength and toughness, but have proven difficult to mimic synthetically. Here, we review the common design motifs of a range of natural structural materials, and discuss the difficulties associated with the design and fabrication of synthetic structures that mimic the structural and mechanical characteristics of their natural counterparts.

  18. Materials science and engineering

    SciTech Connect

    Holden, T.M.

    1995-10-01

    The science-based stockpile stewardship program emphasizes a better understanding of how complex components function through advanced computer calculations. Many of the problem areas are in the behavior of materials making up the equipment. The Los Alamos Neutron Science Center (LANSCE) can contribute to solving these problems by providing diagnostic tools to examine parts noninvasively and by providing the experimental tools to understand material behavior in terms of both the atomic structure and the microstructure. Advanced computer codes need experimental information on material behavior in response to stress, temperature, and pressure as input, and they need benchmarking experiments to test the model predictions for the finished part.

  19. ATS materials/manufacturing

    SciTech Connect

    Karnitz, M.A.; Wright, I.G.; Ferber, M.K.

    1997-11-01

    The Materials/Manufacturing Technology subelement is a part of the base technology portion of the Advanced Turbine Systems (ATS) Program. The work in this subelement is being performed predominantly by industry with assistance from national laboratories and universities. The projects in this subelement are aimed toward hastening the incorporation of new materials and components in gas turbines. Work is currently ongoing on thermal barrier coatings (TBCs), the scale-up of single crystal airfoil manufacturing technologies, materials characterization, and technology information exchange. This paper presents highlights of the activities during the past year. 12 refs., 24 figs., 4 tabs.

  20. On material fracture criteria

    NASA Astrophysics Data System (ADS)

    Kremnev, L. S.

    2017-01-01

    Based on the nonlinear mechanics of material fracture, a model of the fracture of materials with actual (discrete) structures has been constructed. The model is supported by proofs that crack resistance K 1 c and fracture toughness G 1 c obtained from the energy conservation law without using the assumptions adopted in the linear material fracture mechanics serve as the force and energy criteria in the nonlinear fracture mechanics. It has been shown that energy criterion G 1 c in the nonlinear mechanics is much greater than G 1 c in the linear fracture mechanics.

  1. Solid breeder materials

    SciTech Connect

    Johnson, C.E.; Clemmer, R.G.; Hollenber, G.w.

    1981-01-01

    Increased attention is being given to the consideration of lithium-containing ceramic materials for use as breeder blankets in fusion devices. These materials, e.g., Li/sub 2/O, ..gamma..-LiAlO/sub 2/, Li/sub 4/SiO/sub 4/, Li/sub 2/ZrO/sub 3/, etc., are attractive because of their inherent safety advantages. At present, there is a broad scope of laboratory and irradiation activities in force to provide the requisite data enabling selection of th prime-candidate solid breeder material.

  2. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R.; Wiberley, S. E.

    1986-01-01

    Overall emphasis is on basic long-term research in the following categories: constituent materials, composite materials, generic structural elements, processing science technology; and maintaining long-term structural integrity. Research in basic composition, characteristics, and processing science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to present and future problems. Detailed descriptions of the progress achieved in the various component parts of this comprehensive program are presented.

  3. Investigating Encrypted Material

    NASA Astrophysics Data System (ADS)

    McGrath, Niall; Gladyshev, Pavel; Kechadi, Tahar; Carthy, Joe

    When encrypted material is discovered during a digital investigation and the investigator cannot decrypt the material then s/he is faced with the problem of how to determine the evidential value of the material. This research is proposing a methodology of extracting probative value from the encrypted file of a hybrid cryptosystem. The methodology also incorporates a technique for locating the original plaintext file. Since child pornography (KP) images and terrorist related information (TI) are transmitted in encrypted format the digital investigator must ask the question Cui Bono? - who benefits or who is the recipient? By doing this the scope of the digital investigation can be extended to reveal the intended recipient.

  4. Electrically conductive composite material

    DOEpatents

    Clough, R.L.; Sylwester, A.P.

    1988-06-20

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  5. Encapsulation materials research

    NASA Technical Reports Server (NTRS)

    Willis, P. B.

    1984-01-01

    Encapsulation materials for solar cells were investigated. The different phases consisted of: (1) identification and development of low cost module encapsulation materials; (2) materials reliability examination; and (3) process sensitivity and process development. It is found that outdoor photothermal aging devices (OPT) are the best accelerated aging methods, simulate worst case field conditions, evaluate formulation and module performance and have a possibility for life assessment. Outdoor metallic copper exposure should be avoided, self priming formulations have good storage stability, stabilizers enhance performance, and soil resistance treatment is still effective.

  6. Electrically conductive composite material

    SciTech Connect

    Clough, R.L.; Sylwester, A.P.

    1989-05-23

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  7. Composite Structural Materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

    1984-01-01

    The development and application of filamentary composite materials, is considered. Such interest is based on the possibility of using relatively brittle materials with high modulus, high strength, but low density in composites with good durability and high tolerance to damage. Fiber reinforced composite materials of this kind offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been made since the initial developments in the mid 1960's. There were only limited applied to the primary structure of operational vehicles, mainly as aircrafts.

  8. Gravity and Granular Materials

    NASA Technical Reports Server (NTRS)

    Behringer, R. P.; Hovell, Daniel; Kondic, Lou; Tennakoon, Sarath; Veje, Christian

    1999-01-01

    We describe experiments that probe a number of different types of granular flow where either gravity is effectively eliminated or it is modulated in time. These experiments include the shaking of granular materials both vertically and horizontally, and the shearing of a 2D granular material. For the shaken system, we identify interesting dynamical phenomena and relate them to standard simple friction models. An interesting application of this set of experiments is to the mixing of dissimilar materials. For the sheared system we identify a new kind of dynamical phase transition.

  9. Electrically conductive composite material

    DOEpatents

    Clough, Roger L.; Sylwester, Alan P.

    1989-01-01

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistant pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like.

  10. The NASA/JPL Evaluation of Oxygen Interactions with Materials-3 (EOIM-3)

    NASA Technical Reports Server (NTRS)

    Brinza, David E.; Chung, Shirley Y.; Minton, Timothy K.; Liang, Ranty H.

    1994-01-01

    The deleterious effects of hyperthermal atomic oxygen (AO) found in low-earth-orbit (LEO) environments on critical flight materials has been known since early shuttle flights. This corrosive effect is of considerable concern because it compromises the performance and longevity of spacecraft/satellite materials deployed for extended periods in LEO. The NASA Evaluation of Oxygen Interactions with Materials-3 (EOIM-3) experiment served as a testbed for a variety of candidate flight materials for space assets. A total of 57 JPL test specimens were present in six subexperiments aboard EOIM-3. In addition to a number of passive exposure materials for flight and advanced technology programs, several subexperiments were included to provide data for understanding the details of atomic oxygen interactions with materials. Data and interpretations are presented for the heated tray, heated strips, solar ultraviolet exposure, and scatterometer subexperiments, along with a detailed description of the exposure conditions experienced by materials in the various experiments. Mass spectra of products emerging from identical samples of a (sup 13)C-enriched polyimide polymer (chemically equivalent to Kapton) under atomic oxygen bombardment in space and in the laboratory were collected. Reaction products unambiguously detected in space were (sup 13)CO, NO, (sup 12)CO2, and (sup 13)CO2. These reaction products and two others, H2O and (sup 12)CO, were detected in the laboratory, along with inelastically scattered atomic and molecular oxygen. Qualitative agreement was seen in the mass spectra taken in space and in the laboratory; the agreement may be improved by reducing the fraction of O2 in the laboratory molecular beam.

  11. The NASA/JPL Evaluation of Oxygen Interactions with Materials-3 (EOIM-3). Final report

    SciTech Connect

    Brinza, D.E.; Chung, S.Y.; Minton, T.K.; Liang, R.H.

    1994-12-01

    The deleterious effects of hyperthermal atomic oxygen (AO) found in low-earth-orbit (LEO) environments on critical flight materials has been known since early shuttle flights. This corrosive effect is of considerable concern because it compromises the performance and longevity of spacecraft/satellite materials deployed for extended periods in LEO. The NASA Evaluation of Oxygen Interactions with Materials-3 (EOIM-3) experiment served as a testbed for a variety of candidate flight materials for space assets. A total of 57 JPL test specimens were present in six subexperiments aboard EOIM-3. In addition to a number of passive exposure materials for flight and advanced technology programs, several subexperiments were included to provide data for understanding the details of atomic oxygen interactions with materials. Data and interpretations are presented for the heated tray, heated strips, solar ultraviolet exposure, and scatterometer subexperiments, along with a detailed description of the exposure conditions experienced by materials in the various experiments. Mass spectra of products emerging from identical samples of a (sup 13)C-enriched polyimide polymer (chemically equivalent to Kapton) under atomic oxygen bombardment in space and in the laboratory were collected. Reaction products unambiguously detected in space were (sup 13)CO, NO, (sup 12)CO2, and (sup 13)CO2. These reaction products and two others, H2O and (sup 12)CO, were detected in the laboratory, along with inelastically scattered atomic and molecular oxygen. Qualitative agreement was seen in the mass spectra taken in space and in the laboratory; the agreement may be improved by reducing the fraction of O2 in the laboratory molecular beam.

  12. Materials research at CMAM

    NASA Astrophysics Data System (ADS)

    Zucchiatti, Alessandro

    2013-07-01

    The Centro de Micro Analisis de Materiales (CMAM) is a research centre of the Universidad Autónoma de Madrid dedicated to the modification and analysis of materials using ion beam techniques. The infrastructure, based on a HVEE 5MV tandem accelerator, provided with a coaxial Cockcroft Walton charging system, is fully open to research groups of the UAM, to other public research institutions and to private enterprises. The CMAM research covers a few important lines such as advanced materials, surface science, biomedical materials, cultural heritage, materials for energy production. The Centre gives as well support to university teaching and technical training. A detail description of the research infrastructures and their use statistics will be given. Some of the main research results will be presented to show the progress of research in the Centre in the past few years and to motivate the strategic plans for the forthcoming.

  13. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1982-01-01

    The promise of filamentary composite materials, whose development may be considered as entering its second generation, continues to generate intense interest and applications activity. Fiber reinforced composite materials offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been achieved since the initial developments in the mid 1960's. Rather limited applications to primary aircraft structure have been made, however, mainly in a material-substitution mode on military aircraft, except for a few experiments currently underway on large passenger airplanes in commercial operation. To fulfill the promise of composite materials completely requires a strong technology base. NASA and AFOSR recognize the present state of the art to be such that to fully exploit composites in sophisticated aerospace structures, the technology base must be improved. This, in turn, calls for expanding fundamental knowledge and the means by which it can be successfully applied in design and manufacture.

  14. Cookoff of energetic materials

    SciTech Connect

    Baer, M.R.; Hobbs, M.L.; Gross, R.J.; Schmitt, R.G.

    1998-09-01

    An overview of cookoff modeling at Sandia National Laboratories is presented aimed at assessing the violence of reaction following cookoff of confined energetic materials. During cookoff, the response of energetic materials is known to involve coupled thermal/chemical/mechanical processes which induce thermal damage to the energetic material prior to the onset of ignition. These damaged states enhance shock sensitivity and lead to conditions favoring self-supported accelerated combustion. Thus, the level of violence depends on the competition between pressure buildup and stress release due to the loss of confinement. To model these complex processes, finite element-based analysis capabilities are being developed which can resolve coupled heat transfer with chemistry, quasi-static structural mechanics and dynamic response. Numerical simulations that assess the level of violence demonstrate the importance of determining material damage in pre- and post-ignition cookoff events.

  15. Mesoporous carbon materials

    SciTech Connect

    Dai, Sheng; Wang, Xiqing

    2013-08-20

    The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

  16. Mesoporous carbon materials

    SciTech Connect

    Dai, Sheng; Wang, Xiqing

    2012-02-14

    The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

  17. Materials research at CMAM

    SciTech Connect

    Zucchiatti, Alessandro

    2013-07-18

    The Centro de Micro Analisis de Materiales (CMAM) is a research centre of the Universidad Autonoma de Madrid dedicated to the modification and analysis of materials using ion beam techniques. The infrastructure, based on a HVEE 5MV tandem accelerator, provided with a coaxial Cockcroft Walton charging system, is fully open to research groups of the UAM, to other public research institutions and to private enterprises. The CMAM research covers a few important lines such as advanced materials, surface science, biomedical materials, cultural heritage, materials for energy production. The Centre gives as well support to university teaching and technical training. A detail description of the research infrastructures and their use statistics will be given. Some of the main research results will be presented to show the progress of research in the Centre in the past few years and to motivate the strategic plans for the forthcoming.

  18. Unusual spacecraft materials

    NASA Technical Reports Server (NTRS)

    Post, Jonathan V.

    1990-01-01

    For particularly innovative space exploration missions, unusual requirements are levied on the structural components of the spacecraft. In many cases, the preferred solution is the utilization of unusual materials. This trend is forecast to continue. Several hypothetic examples are discussed.

  19. Reversible hydrogen storage materials

    DOEpatents

    Ritter, James A [Lexington, SC; Wang, Tao [Columbia, SC; Ebner, Armin D [Lexington, SC; Holland, Charles E [Cayce, SC

    2012-04-10

    In accordance with the present disclosure, a process for synthesis of a complex hydride material for hydrogen storage is provided. The process includes mixing a borohydride with at least one additive agent and at least one catalyst and heating the mixture at a temperature of less than about 600.degree. C. and a pressure of H.sub.2 gas to form a complex hydride material. The complex hydride material comprises MAl.sub.xB.sub.yH.sub.z, wherein M is an alkali metal or group IIA metal, Al is the element aluminum, x is any number from 0 to 1, B is the element boron, y is a number from 0 to 13, and z is a number from 4 to 57 with the additive agent and catalyst still being present. The complex hydride material is capable of cyclic dehydrogenation and rehydrogenation and has a hydrogen capacity of at least about 4 weight percent.

  20. Semiconductivity in Organoarsenic Materials.

    DTIC Science & Technology

    1977-12-01

    A general investigation of the macromolecule formation abilities of the hypothetical monomeric unit, RE, where R is an organic group and E either arsenic or antimony, resulted in the development of several novel crystalline materials possessing

  1. Photoconductivity in Dirac materials

    SciTech Connect

    Shao, J. M.; Yang, G. W.

    2015-11-15

    Two-dimensional (2D) Dirac materials including graphene and the surface of a three-dimensional (3D) topological insulator, and 3D Dirac materials including 3D Dirac semimetal and Weyl semimetal have attracted great attention due to their linear Dirac nodes and exotic properties. Here, we use the Fermi’s golden rule and Boltzmann equation within the relaxation time approximation to study and compare the photoconductivity of Dirac materials under different far- or mid-infrared irradiation. Theoretical results show that the photoconductivity exhibits the anisotropic property under the polarized irradiation, but the anisotropic strength is different between 2D and 3D Dirac materials. The photoconductivity depends strongly on the relaxation time for different scattering mechanism, just like the dark conductivity.

  2. Evaluation of sorbent materials

    SciTech Connect

    Rankin, W.N.; Gomillion, S.L.; Luckenbach, R.L.

    1989-01-01

    The sorption efficiency of different types of liquid sorbent materials was determined under carefully controlled laboratory conditions. Results show that the sorption capacity is affected both by the type of material and by the form of the material. Attractive alternate sorbents to ''atomic wipes'' and Oil-Dry were identified. Small pillows of shredded synthetic sorbents are an attractive alternative to Oil-Dry as a sorbent and to ''atomic wipes'' as both a sorbent and in decontamination by wiping. Synthetic sorbents in cloth form offer an attractive alternative to ''atomic wipes'' in decontamination by wiping because these materials are compatible with nitric acid and they may be more fire resistant. A larger-scale evaluation is planned with the most promising sorbents. In addition, development is planned of a sorbent that will be efficient, compatible with nitric acid and fire resistant. 6 refs., 2 tabs.

  3. Evaluation of sorbent materials

    SciTech Connect

    Rankin, W N; Gomillion, S L; Luckenbach, R L

    1989-01-01

    The sorption efficiency of different types of liquid sorbent materials was determined under carefully controlled laboratory conditions. Results show that the sorption capacity is affected both by the type of material and by the form of the material. Attractive alternate sorbents to atomic wipes'' and Oil-Dry were identified. Small pillows of shredded synthetic sorbents are an attractive alternative to Oil-Dry as a sorbent and to atomic wipes'' as both a sorbent and in decontamination by wiping. Synthetic sorbents in cloth form offer an attractive alternative to atomic wipes'' in decontamination by wiping because theses materials are compatible with nitric acid and they may be more fire resistant. A larger-scale evaluation is planned with the most promising sorbents. In addition, development is planned of a sorbent that will be efficient, compatible with nitric acid, fire resistant. 6 refs., 2 tabs.

  4. Building Materials Property Table

    SciTech Connect

    2010-04-16

    This information sheet describes a table of some of the key technical properties of many of the most common building materials taken from ASHRAE Fundamentals - 2001, Moisture Control in Buildings, CMHC, NRC/IRC, IEA Annex 24, and manufacturer data.

  5. Dynamics of Granular Materials

    NASA Technical Reports Server (NTRS)

    Behringer, Robert P.

    1996-01-01

    Granular materials exhibit a rich variety of dynamical behavior, much of which is poorly understood. Fractal-like stress chains, convection, a variety of wave dynamics, including waves which resemble capillary waves, l/f noise, and fractional Brownian motion provide examples. Work beginning at Duke will focus on gravity driven convection, mixing and gravitational collapse. Although granular materials consist of collections of interacting particles, there are important differences between the dynamics of a collections of grains and the dynamics of a collections of molecules. In particular, the ergodic hypothesis is generally invalid for granular materials, so that ordinary statistical physics does not apply. In the absence of a steady energy input, granular materials undergo a rapid collapse which is strongly influenced by the presence of gravity. Fluctuations on laboratory scales in such quantities as the stress can be very large-as much as an order of magnitude greater than the mean.

  6. Tough Composite Materials

    NASA Technical Reports Server (NTRS)

    Vosteen, L. F. (Compiler); Johnson, N. J. (Compiler); Teichman, L. A. (Compiler)

    1984-01-01

    Papers and working group summaries are presented which address composite material behavior and performance improvement. Topic areas include composite fracture toughness and impact characterization, constituent properties and interrelationships, and matrix synthesis and characterization.

  7. Designing Printed Instructional Materials.

    ERIC Educational Resources Information Center

    Burbank, Lucille; Pett, Dennis

    1986-01-01

    Discusses the importance of identifying the audience and determining specific objectives when designing printed instructional materials that will communicate effectively and provides detailed guidelines for dealing with such design factors as content, writing style, typography, illustrations, and page organization. (MBR)

  8. Instrumentation for Materials Research

    ERIC Educational Resources Information Center

    Claassen, Richard S.

    1976-01-01

    Discusses how sophisticated instrumentation techniques yield practical results in three typical materials problems: fracture analysis, joining, and compatibility. Describes techniques such as scanning and transmission electron microscopy, and Auger spectroscopy. (MLH)

  9. Computational Materials Research

    NASA Technical Reports Server (NTRS)

    Veazie, David R.

    1998-01-01

    High temperature thermoplastic polyimide polymers are incorporated in engineering structures in the form of matrix materials in advanced fiber composites and adhesives in bonded joints. Developing analytical tools to predict long term performance and screen for final materials selection for polymers is the impetus for intensive studies at NASA and major industry based airframe developers. These fiber-reinforced polymeric composites (FRPCs) combine high strength with lightweight. In addition, they offer corrosion and fatigue resistance, a reduction in parts count, and new possibilities for control through aeroelastic tailoring and "smart" structures containing fully-integrated sensors and actuators. However, large-scale acceptance and use of polymer composites has historically been extremely slow. Reasons for this include a lack of familiarity of designers with the materials; the need for new tooling and new inspection and repair infrastructures; and high raw materials and fabrication costs.

  10. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1979-01-01

    Technology utilization of fiber reinforced composite materials is discussed in the areas of physical properties, and life prediction. Programs related to the Composite Aircraft Program are described in detail.

  11. Degradation of Spacecraft Materials

    NASA Technical Reports Server (NTRS)

    Dever, Joyce; Banks, Bruce; deGroh, Kim; Miller, Sharon

    2004-01-01

    This chapter includes descriptions of specific space environmental threats to exterior spacecraft materials. The scope will be confined to effects on exterior spacecraft surfaces, and will not, therefore, address environmental effects on interior spacecraft systems, such as electronics. Space exposure studies and laboratory simulations of individual and combined space environemntal threats will be summarized. A significant emphasis is placed on effects of Earth orbit environments, because the majority of space missions have been flown in Earth orbits which have provided a significant amount of data on materials effects. Issues associated with interpreting materials degradation results will be discussed, and deficiencies of ground testing will be identified. Recommendations are provided on reducing or preventing space environmental degradation through appropriate materials selection.

  12. Materials engineering data base

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The various types of materials related data that exist at the NASA Marshall Space Flight Center and compiled into databases which could be accessed by all the NASA centers and by other contractors, are presented.

  13. Burn Wise - Outreach Materials

    EPA Pesticide Factsheets

    Burn Wise outreach material. Burn Wise is a partnership program of that emphasizes the importance of burning the right wood, the right way, in the right wood-burning appliance to protect your home, health, and the air we breathe.

  14. Holographic Recording Materials Development

    NASA Technical Reports Server (NTRS)

    Verber, C. M.; Schwerzel, R. E.; Perry, P. J.; Craig, R. A.

    1976-01-01

    Organic photorefractive materials were evaluated for application in a reversible holographic memory system. Representative indigo and thioindigo derivatives and several stilbene derivatives were studied as well as 15, 16-dialkyldihydropyrene derivatives the following goals were achieved: (1) the successful writing of phase holograms in a thioindigo/polymer gel system, (2) the successful writing and erasing of phase holograms in a variety of indigo/polymer gel and indigo/solid polymer systems, and (3) the identification of indigoid dyes and 15, 16-dialkyldihydropyrene derivatives as materials potentially suitable for utilization in an operational system. Photochemical studies of the stilbene, indigo, thioindigo, and dialkyldihydropyrene derivatives in solution and in a variety of polymer matrix materials were conducted with the goal of optimizing the photorefractive behavior of the chemical system as a whole. The spectroscopic properties required of optimal photorefractive materials were identified, and it was shown that both the indigoid dyes and the dialkyldihydropyrenes closely match the required properties.

  15. Indigenous lunar construction materials

    NASA Technical Reports Server (NTRS)

    Rogers, Wayne; Sture, Stein

    1991-01-01

    The objectives are the following: to investigate the feasibility of the use of local lunar resources for construction of a lunar base structure; to develop a material processing method and integrate the method with design and construction of a pressurized habitation structure; to estimate specifications of the support equipment necessary for material processing and construction; and to provide parameters for systems models of lunar base constructions, supply, and operations. The topics are presented in viewgraph form and include the following: comparison of various lunar structures; guidelines for material processing methods; cast lunar regolith; examples of cast basalt components; cast regolith process; processing equipment; mechanical properties of cast basalt; material properties and structural design; and future work.

  16. Developments in carbon materials

    NASA Technical Reports Server (NTRS)

    Burchell, Timothy D.

    1994-01-01

    The following carbon-based materials are reviewed and their applications discussed: fullerenes; graphite (synthetic and manufactured); activated carbon fibers; and carbon-carbon composites. Carbon R&D activities at ORNL are emphasized.

  17. Nuclear material operations manual

    SciTech Connect

    Tyler, R.P.

    1981-02-01

    This manual provides a concise and comprehensive documentation of the operating procedures currently practiced at Sandia National Laboratories with regard to the management, control, and accountability of nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations-management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of playscripts in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion.

  18. Electrically conductive material

    DOEpatents

    Singh, Jitendra P.; Bosak, Andrea L.; McPheeters, Charles C.; Dees, Dennis W.

    1993-01-01

    An electrically conductive material for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO.sub.2 as a matrix and 6-19 wt. % monoclinic ZrO.sub.2 formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO.sub.2 as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns.

  19. Electrically conductive material

    DOEpatents

    Singh, J.P.; Bosak, A.L.; McPheeters, C.C.; Dees, D.W.

    1993-09-07

    An electrically conductive material is described for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO[sub 2] as a matrix and 6-19 wt. % monoclinic ZrO[sub 2] formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO[sub 2] as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns. 8 figures.

  20. Sustainable Materials Management Basics

    EPA Pesticide Factsheets

    SMM is a systemic approach to using and reusing materials more productively over their entire lifecycles. It represents a change in how our society thinks about the use of natural resources and environmental protection

  1. Lunar material transport vehicle

    NASA Technical Reports Server (NTRS)

    Fisher, Charles D.; Lyons, Douglas; Wilkins, W. Allen, Jr.; Whitehead, Harry C., Jr.

    1988-01-01

    The proposed vehicle, the Lunar Material Transport Vehicle (LMTV), has a mission objective of efficient lunar soil material transport. The LMTV was designed to meet a required set of performance specifications while operating under a given set of constraints. The LMTV is essentially an articulated steering, double-ended dump truck. The vehicle moves on four wheels and has two identical chassis halves. Each half consists of a chassis frame, a material bucket, two wheels with integral curvilinear synchronous motors, a fuel cell and battery arrangement, an electromechanically actuated dumping mechanism, and a powerful microprocessor. The vehicle, as designed, is capable of transporting up to 200 cu ft of material over a one mile round trip per hour. The LMTV is capable of being operated from a variety of sources. The vehicle has been designed as simply as possible with attention also given to secondary usage of components.

  2. Moldable cork ablation material

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

  3. Materials inspired by mathematics.

    PubMed

    Kotani, Motoko; Ikeda, Susumu

    2016-01-01

    Our world is transforming into an interacting system of the physical world and the digital world. What will be the materials science in the new era? With the rising expectations of the rapid development of computers, information science and mathematical science including statistics and probability theory, 'data-driven materials design' has become a common term. There is knowledge and experience gained in the physical world in the form of know-how and recipes for the creation of material. An important key is how we establish vocabulary and grammar to translate them into the language of the digital world. In this article, we outline how materials science develops when it encounters mathematics, showing some emerging directions.

  4. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1984-01-01

    Progress is reported in studies of constituent materials composite materials, generic structural elements, processing science technology, and maintaining long-term structural integrity. Topics discussed include: mechanical properties of high performance carbon fibers; fatigue in composite materials; experimental and theoretical studies of moisture and temperature effects on the mechanical properties of graphite-epoxy laminates and neat resins; numerical investigations of the micromechanics of composite fracture; delamination failures of composite laminates; effect of notch size on composite laminates; improved beam theory for anisotropic materials; variation of resin properties through the thickness of cured samples; numerical analysis composite processing; heat treatment of metal matrix composites, and the RP-1 and RP2 gliders of the sailplane project.

  5. Heavy Vehicle Propulsion Materials

    SciTech Connect

    Ray Johnson

    2000-01-31

    The objectives are to Provide Key Enabling Materials Technologies to Increase Energy Efficiency and Reduce Exhaust Emissions. The following goals are listed: Goal 1: By 3rd quarter 2002, complete development of materials enabling the maintenance or improvement of fuel efficiency {ge} 45% of class 7-8 truck engines while meeting the EPA/Justice Department ''Consent Decree'' for emissions reduction. Goal 2: By 4th quarter 2004, complete development of enabling materials for light-duty (class 1-2) diesel truck engines with efficiency over 40%, over a wide range of loads and speeds, while meeting EPA Tier 2 emission regulations. Goal 3: By 4th quarter 2006, complete development of materials solutions to enable heavy-duty diesel engine efficiency of 50% while meeting the emission reduction goals identified in the EPA proposed rule for heavy-duty highway engines.''

  6. Materials inspired by mathematics

    PubMed Central

    Kotani, Motoko; Ikeda, Susumu

    2016-01-01

    Abstract Our world is transforming into an interacting system of the physical world and the digital world. What will be the materials science in the new era? With the rising expectations of the rapid development of computers, information science and mathematical science including statistics and probability theory, ‘data-driven materials design’ has become a common term. There is knowledge and experience gained in the physical world in the form of know-how and recipes for the creation of material. An important key is how we establish vocabulary and grammar to translate them into the language of the digital world. In this article, we outline how materials science develops when it encounters mathematics, showing some emerging directions. PMID:27877877

  7. Concise polymeric materials encyclopedia

    SciTech Connect

    Salamone, J.C.

    1999-01-01

    This comprehensive, accessible resource abridges the ``Polymeric Materials Encyclopedia'', presenting more than 1,100 articles and featuring contributions from more than 1,800 scientists from all over the world. The text discusses a vast array of subjects related to the: (1) synthesis, properties, and applications of polymeric materials; (2) development of modern catalysts in preparing new or modified polymers; (3) modification of existing polymers by chemical and physical processes; and (4) biologically oriented polymers.

  8. Keeping Nuclear Materials Secure

    SciTech Connect

    2016-10-19

    For 50 years, Los Alamos National Laboratory has been helping to keep nuclear materials secure. We do this by developing instruments and training inspectors that are deployed to other countries to make sure materials such as uranium are being used for peaceful purposes and not diverted for use in weapons. These measures are called “nuclear safeguards,” and they help make the world a safer place.

  9. Nano-composite materials

    DOEpatents

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  10. Fibre-reinforced materials.

    PubMed

    Brown, D

    2000-11-01

    This paper considers the role of fibres in the reinforcement of composite materials, and the significance of the form the fibre takes and the material from which it is made. The current dental applications of fibre reinforcement, including dental cements and splints, fibres made into structures for use in composites, denture bases and the contemporary use of fibres in fixed partial dentures, are reviewed. Their role in biomedical implants is surveyed and their future forecast.

  11. Nonmetallic Materials Handbook

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A handbook compilation of chemical and physical property tests data obtained during qualification and receiving inspection testing of nonmetallic materials for the Viking Lander is introduced. Data cover the following materials: sealants, potting compounds, lubricants, paints and finishes, inks, films, encapsulants, elastomers, structural plastics, ablatives, adhesives, and electrical and thermal insulation. Thermochemical data showing degradation as a function of temperature, from room to 500 C, are included.

  12. Container for radioactive materials

    DOEpatents

    Fields, Stanley R.

    1985-01-01

    A container for housing a plurality of canister assemblies containing radioactive material and disposed in a longitudinally spaced relation within a carrier to form a payload package concentrically mounted within the container. The payload package includes a spacer for each canister assembly, said spacer comprising a base member longitudinally spacing adjacent canister assemblies from each other and a sleeve surrounding the associated canister assembly for centering the same and conducting heat from the radioactive material in a desired flow path.

  13. Materials with negative stiffness

    NASA Astrophysics Data System (ADS)

    Jaglinski, Tim

    Negative stiffness, or a reversal in the usual assumed direction between causal forces and ensuing deformations, has been proposed as a pathway to materials which exceed theoretical performance bounds. Negative stiffness, as a concept, represents a relaxation of tacitly assumed material behavior, but it violates no natural laws. Negative stiffness, normally unstable without constraint, is permissible for stability under special conditions, for example a rigid boundary constraint so long as the material satisfies strong ellipticity in the parlance of elasticity. Hence, negative stiffness is not observed in materials or structures which are not constrained. If negative stiffness is allowed for inclusions of material, which are surrounded by a stabilizing positive stiffness matrix, composite theory predicts large increases in the mechanical damping and composite stiffness. The work herein explores several material systems which possess negative stiffness, and seeks to characterize the composite mechanical properties of these systems. Two metal matrix composite systems, namely Sn-VO2 and Sn-BaTIO3, were investigated. Here, negative stiffness arises from the ferroelastic phase transformations in the ceramic inclusions; stability is imparted by the tin matrix. Polycrystalline In-Tl and BaTIO 3 were also studied. Here, the entire material volume is phase transforming. Constraint is imparted on a small volume fraction of crystallites by the surrounding material. Various manifestations of negative stiffness were observed. Thermally broad damping peaks which depended upon thermal cycling were observed in the Sn-VO2 composites. Furthermore, mechanical instabilities were seen in composites intentionally designed to be unstable. Negative stiffness was indicated in the In-Tl alloy by magnification of damping peaks over those observed in single crystals, increases in damping peaks with increased cooling rates, occurrence of damping peaks before the appearance of martensite and

  14. Microwave Processing of Materials

    DTIC Science & Technology

    1994-01-01

    of peak output power of 100 megawatts at 10 GHz. Microwave Fundamentals 11 RESONANT HELIX TWT STO KLYSTRON CTf C 0 Grid oShadow Grid PPM FOCUS SPACE C...Rather, broadband and high-temperature measurement techniques that have been used in conjunction with microwave processing of materials-specifically... Broadband Dielectric Properties Measurement Techniques. Pp. 527-539 in Materials Research Society Symposium Proceedings, Vol. 269, Microwave Processing

  15. Optical materials research.

    PubMed

    Parsons, W F

    1972-01-01

    There are eras in research when days are filled with excitement because unique materials are being produced and researchers "think what nobody else has thought" (Albert von Szent Gyorgyi). Such were the periods when many new optical glasses emerged from the laboratories of the Eastman Kodak Company and when the hot pressing technology was applied to produce new polycrystalline materials. This paper discusses the people and accomplishments of those periods.

  16. Multifunctional Metallosupramolecular Materials

    DTIC Science & Technology

    2011-02-28

    Approaches to Stimuli-Responsive Materials: From Sea Cucumbers to Self-Healing Films. Oct 2010 University of Wisconsin, Madison, USA Invited Lecture...2008 Lubrizol, Wickliffe, Ohio Invited Lecture: Supramolecular Materials: From Re-healable Plastics to Sea Cucumbers Dec 2008 US-Japan Polymer...scholarships or fellowships for further studies in science, mathematics, engineering or technology fields: 0.00 0.00 0.00 0.00 0.00 0.00

  17. Materials Coating Techniques

    DTIC Science & Technology

    1980-03-01

    properties of the coating layers and their interaction with the bulk material will be considered. Lectures will also cover the behaviour of coated parts...stability etc. Finally, available techniques for the analysis and non-destructive evaluation of the composition. properties and soundness of the...provide stiffness or flexibility, and to carry the applied loads without macroscopic failure. Such properties are associated with the bulk material of

  18. Beam-Material Interaction

    SciTech Connect

    Mokhov, N. V.; Cerutti, F.

    2016-01-01

    Th is paper is motivated by the growing importance of better understanding of the phenomena and consequences of high-intensity energetic particle beam interactions with accelerator, generic target, and detector components. It reviews the principal physical processes of fast-particle interactions with matter, effects in materials under irradiation, materials response, related to component lifetime and performance, simulation techniques, and methods of mitigating the impact of radiation on the components and environment in challenging current and future applications.

  19. Noise Abatement Materials

    NASA Technical Reports Server (NTRS)

    1986-01-01

    A former NASA employee who discovered a kind of plastic that soaked up energy, dampened vibrations, and was a good noise abatement material, founded a company to market noise deadening adhesives, sheets, panels and enclosures. Known as SMART products, they are 75-80% lighter than ordinary soundproofing material and have demonstrated a high degree of effectiveness. The company, Varian Associates, makes enclosures for high voltage terminals and other electronic system components, and easily transportable audiometric test booths.

  20. Biomimetic Hydrogel Materials

    DOEpatents

    Bertozzi, Carolyn , Mukkamala, Ravindranath , Chen, Oing , Hu, Hopin , Baude, Dominique

    2003-04-22

    Novel biomimetic hydrogel materials and methods for their preparation. Hydrogels containing acrylamide-functionalized carbohydrate, sulfoxide, sulfide or sulfone copolymerized with a hydrophilic or hydrophobic copolymerizing material selected from the group consisting of an acrylamide, methacrylamide, acrylate, methacrylate, vinyl and a derivative thereof present in concentration from about 1 to about 99 wt %. and methods for their preparation. The method of use of the new hydrogels for fabrication of soft contact lenses and biomedical implants.

  1. Biomimetic hydrogel materials

    SciTech Connect

    Bertozzi, Carolyn; Mukkamala, Ravindranath; Chen, Qing; Hu, Hopin; Baude, Dominique

    2000-01-01

    Novel biomimetic hydrogel materials and methods for their preparation. Hydrogels containing acrylamide-functionalized carbohydrate, sulfoxide, sulfide or sulfone copolymerized with a hydrophilic or hydrophobic copolymerizing material selected from the group consisting of an acrylamide, methacrylamide, acrylate, methacrylate, vinyl and a derivative thereof present in concentration from about 1 to about 99 wt %. and methods for their preparation. The method of use of the new hydrogels for fabrication of soft contact lenses and biomedical implants.

  2. Plasma Processing of Materials

    DTIC Science & Technology

    1985-02-22

    Estimates for Producing Alu -.. a from Domestic Raw Materials. U.S. Bureau ot Mines Information Circ lar 8648. 6. Barclay, James A., arti Frank A...heating occurs via joule -type heating, whereas cleaning is believed to occur via vaporization of thin oxide films from cathodic arc spots caused by a...Research Society Symposium on Plasma Processing and Synthesis of Materials, Boston, November. 43. Frind, G., C. P. Goody, and L. E. Prescott . 1983

  3. Ceramic Laser Materials

    SciTech Connect

    Soules, T F; Clapsaddle, B J; Landingham, R L; Schaffers, K I

    2005-02-15

    Transparent ceramic materials have several major advantages over single crystals in laser applications, not the least of which is the ability to make large aperture parts in a robust manufacturing process. After more than a decade of working on making transparent YAG:Nd, Japanese workers have recently succeeded in demonstrating samples that performed as laser gain media as well as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. We have established a good working relationship with Konoshima Ltd., the Japanese producer of the best ceramic laser materials, and have procured and evaluated slabs designed by us for use in our high-powered SSHCL. Our measurements indicate that these materials will work in the SSHCL, and we have nearly completed retrofitting the SSHCL with four of the largest transparent ceramic YAG:Nd slabs in existence. We have also begun our own effort to make this material and have produced samples with various degrees of transparency/translucency. We are in the process of carrying out an extensive design-of-experiments to establish the significant process variables for making transparent YAG. Finally because transparent ceramics afford much greater flexibility in the design of lasers, we have been exploring the potential for much larger apertures, new materials, for example for the Mercury laser, other designs for SSHL, such as, edge pumping designs, slabs with built in ASE suppression, etc. This work has just beginning.

  4. Food Packaging Materials

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The photos show a few of the food products packaged in Alure, a metallized plastic material developed and manufactured by St. Regis Paper Company's Flexible Packaging Division, Dallas, Texas. The material incorporates a metallized film originally developed for space applications. Among the suppliers of the film to St. Regis is King-Seeley Thermos Company, Winchester, Ma'ssachusetts. Initially used by NASA as a signal-bouncing reflective coating for the Echo 1 communications satellite, the film was developed by a company later absorbed by King-Seeley. The metallized film was also used as insulating material for components of a number of other spacecraft. St. Regis developed Alure to meet a multiple packaging material need: good eye appeal, product protection for long periods and the ability to be used successfully on a wide variety of food packaging equipment. When the cost of aluminum foil skyrocketed, packagers sought substitute metallized materials but experiments with a number of them uncovered problems; some were too expensive, some did not adequately protect the product, some were difficult for the machinery to handle. Alure offers a solution. St. Regis created Alure by sandwiching the metallized film between layers of plastics. The resulting laminated metallized material has the superior eye appeal of foil but is less expensive and more easily machined. Alure effectively blocks out light, moisture and oxygen and therefore gives the packaged food long shelf life. A major packaging firm conducted its own tests of the material and confirmed the advantages of machinability and shelf life, adding that it runs faster on machines than materials used in the past and it decreases product waste; the net effect is increased productivity.

  5. Materials Processing in Space

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.

    1982-01-01

    A report describes investigations of materials processing in low-gravity environment. Ultimately, research could lead to new commercially-applicable materials and processes and to an understanding of constraints imposed by gravity. NASA-supported work is carried out in 46 academic, industrial, and Government laboratories, and covers a number of areas. An overview is given of objective and current state of development for over 100 tasks.

  6. NMR imaging of materials

    SciTech Connect

    Vinegar, H.J.; Rothwell, W.P.

    1988-03-01

    A method for obtaining at least one petrophysical property of a porous material containing therein at least one preselected fluid, is described, comprising: NMR imaging the material to generate signals dependent upon both M(0) and T/sub 1/ and M(0) and T/sub 2/, generating separate M(0), T/sub 1/ and T/sub 2/ images from the signals, and determining at least one petrophysical property from at least one of the images.

  7. Enzymes on material surfaces.

    PubMed

    Talbert, Joey N; Goddard, Julie M

    2012-05-01

    Enzyme interactions with material surfaces are of interest for industrial food and pharmaceutical transformations, biosensors, artificial cells, cell free reactions, drug and nutrition delivery technologies, and imaging. When in contact with a material surface, an enzyme may lose or appear to lose activity due to the nature of the enzyme, the nature of the material, and/or the nature of the interface between the enzyme, material, and substrate environment. The purpose of this review is to survey recent advances that have been made towards the preservation, optimization, and enhancement of enzyme activity on material surfaces within the context of well-known concepts that describe the loss of activity after immobilization. This review breaks down the immobilized enzyme system to look at the individual components of the system-namely the enzyme, the material, and the interface. For each piece, possible causes for the loss of enzyme activity are described as well as strategies that have been applied to limit the affect. At the conclusion we identify areas of future research needed to overcome limitations in the current state-of-the art for immobilized enzyme systems.

  8. Superconducting materials processing

    NASA Astrophysics Data System (ADS)

    Hurley, John S.; Karikari, Emmanuel K.; Hiamang, S. O.; Danjaji, M.; Bassey, Affiong; Morgan, Andre

    1995-08-01

    The effects of materials processing on the properties and behavior of high temperature yttrium barium copper oxide (YBCO) superconductors were investigated. Electrical, magnetic, and structural characteristics of thin films (300 nm) YBA2CU3O(delta) structures grown by pulsed laser deposition on LaAlO3 and SrTiO3 substrates were used to evaluate processing. Pole projection and thin film diffraction measurements were used to establish grain orientation and verify structural integrity of the samples. Susceptibility magnetization, and transport measurements were used to evaluate the magnetic and electrical transport properties of the samples. Our results verified that an unfortunate consequence of processing is inherent changes to the internal structure of the material. This effect translates into modifications in the properties of the materials, and undesired feature that makes it very difficult to consistently predict material behavior. The results show that processing evaluation must incorporate a comprehensive understanding of the properties of the materials. Future studies will emphasize microstructural characteristics of the materials, in particular, those microscopic properties that map macroscopic behavior.

  9. LDEF materials data bases

    NASA Technical Reports Server (NTRS)

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1993-01-01

    The Long Duration Exposure Facility (LDEF) and the accompanying experiments were composed of and contained a wide variety of materials representing the largest collection of materials flown in low Earth orbit (LEO) and retrieved for ground based analysis to date. The results and implications of the mechanical, thermal, optical, and electrical data from these materials are the foundation on which future LEO space missions will be built. The LDEF Materials Special Investigation Group (MSIG) has been charged with establishing and developing data bases to document these materials and their performance to assure not only that the data are archived for future generations but also that the data are available to the spacecraft user community in an easily accessed, user-friendly form. This paper discusses the format and content of the three data bases developed or being developed to accomplish this task. The hardware and software requirements for each of these three data bases are discussed along with current availability of the data bases. This paper also serves as a user's guide to the MAPTIS LDEF Materials Data Base.

  10. Superconducting materials processing

    NASA Technical Reports Server (NTRS)

    Hurley, John S.; Karikari, Emmanuel K.; Hiamang, S. O.; Danjaji, M.; Bassey, Affiong; Morgan, Andre

    1995-01-01

    The effects of materials processing on the properties and behavior of high temperature yttrium barium copper oxide (YBCO) superconductors were investigated. Electrical, magnetic, and structural characteristics of thin films (300 nm) YBA2CU3O(delta) structures grown by pulsed laser deposition on LaAlO3 and SrTiO3 substrates were used to evaluate processing. Pole projection and thin film diffraction measurements were used to establish grain orientation and verify structural integrity of the samples. Susceptibility magnetization, and transport measurements were used to evaluate the magnetic and electrical transport properties of the samples. Our results verified that an unfortunate consequence of processing is inherent changes to the internal structure of the material. This effect translates into modifications in the properties of the materials, and undesired feature that makes it very difficult to consistently predict material behavior. The results show that processing evaluation must incorporate a comprehensive understanding of the properties of the materials. Future studies will emphasize microstructural characteristics of the materials, in particular, those microscopic properties that map macroscopic behavior.

  11. EDITORIAL: Materially speaking!

    NASA Astrophysics Data System (ADS)

    Cornwall, Malcolm G.

    1997-05-01

    We live in a highly materialistic age. This is true not only for our spiritual outlook - or lack of it - but undeniably so for the physical world in which we live. Materials, which are the feature of this special issue, provide literally the fabric on which the modern world is built. Materials science is the systematic study of the physical properties and behaviour of solids with practical applications and importance (if the utility of the material is not explicit or important we are probably in the realm of solid state physics!). Materials in this sense are the stuff of which cars and computers, jet aircraft and washing machines, tower blocks and saucepans, bridges and golf clubs are made. The science of materials therefore encompasses most of the things that form the infrastructure of modern life. But perhaps it is its very ubiquity that removes the mystique, the glamour, the 'zing' from the subject. In contrast, anything cosmological, astronomical or 'fundamental' (as in 'particle'), i.e. of little or no practical significance to our day-to-day lives, excites the curiosity of many able young people. Witness the profusion of books about galaxies and black holes, and quarks and GUTs which strain the popular science shelves of the bookshops. I'm probably being heretical, but perhaps the over-hyping of the very large and the very small has indeed attracted the able few into the serious study of physics, but because of its inherent mathematical complexity and esoteric remoteness maybe it has put off the average youngster who would nevertheless enjoy and succeed in physics-based higher education (and, not incidentally, help fill the seriously depleted lecture theatres in many university physics - and engineering - departments). Materials science on the other hand deals with an intermediate range of things which, give or take an order of magnitude or three, are person-sized as well as person useful. It is - therefore? - undoubtedly one of the less glamorous of the

  12. Organic Material Based Fluorescent Sensor for Hg(2+): a Brief Review on Recent Development.

    PubMed

    Saleem, Muhammad; Rafiq, Muhammad; Hanif, Muhammad

    2017-01-01

    Due to the deleterious effects of mercury on human health and natural ecosystems, high reactivity, non-degradability, extreme volatility and relative water and tissue solubility, it would consider as one of the most toxic environmental pollutants among the transition metals. In the present investigation, we have tried to summarized the several organic material based fluorescent sensor including rhodamine, boron-dipyrromethene (BODIPYs), thiourea, crown-ether, coumarine, squaraines, pyrene, imidazole, triazole, anthracene, dansyl, naphthalenedimide/ naphthalene/ naphthalimide, naphthyridine, iridium (III) complexes, polymeric materials, cyclodextrin, phthalic anhydride, indole, calix [4]arene, chromenone, 1,8-naphthalimides, lysine, styrylindolium, phenothiazine, thiocarbonyl quinacridone, oxadiazole, triphenylamine-triazines, tetraphenylethene, peptidyl and semicarbazone for the trace mercury detection in the aqueous, aqueous-organic and cellular media. The present review provides a brief look over the previous development in the organic material based fluorescent sensor for mercuric ion detection. Furthermore, the ligand-metal binding stoichiometry, binding/association/dissociation constants and the detection limit by the receptors have been particularly highlighted which might be useful for the future design and development of more sensitive and robust fluorescent chemosensor/chemodosimeter for the mercuric ion detection. Graphical Abstract Dummy.

  13. Tribological comparison of materials

    NASA Astrophysics Data System (ADS)

    Shi, Bing

    Approximately 600,000 total joint replacement surgeries are performed each year in the United States. Current artificial joint implants are mainly metal-on-plastic. The synthetic biomaterials undergo degradation through fatigue and corrosive wear from load-bearing and the aqueous ionic environment of the human body. Deposits of inorganic salts can scratch weight-bearing surfaces, making artificial joints stiff and awkward. The excessive wear debris from polyethylene leads to osteolysis and potential loosening of the prosthesis. The lifetime for well-designed artificial joints is at most 10 to 15 years. A patient can usually have two total joint replacements during her/his lifetime. Durability is limited by the body's reaction to wear debris of the artificial joints. Wear of the artificial joints should be reduced. A focus of this thesis is the tribological performance of bearing materials for Total Replacement Artificial Joints (TRAJ). An additional focus is the scaffolds for cell growth from both a tissue engineering and tribological perspective. The tribological properties of materials including Diamond-like Carbon (DLC) coated materials were tested for TRAJ implants. The DLC coatings are chemically inert, impervious to acid and saline media, and are mechanically hard. Carbon-based materials are highly biocompatible. A new alternative to total joints implantation is tissue engineering. Tissue engineering is the replacement of living tissue with tissue that is designed and constructed to meet the needs of the individual patient. Cells were cultured onto the artificial materials, including metals, ceramics, and polymers, and the frictional properties of these materials were investigated to develop a synthetic alternative to orthopedic transplants. Results showed that DLC coated materials had low friction and wear, which are desirable tribological properties for artificial joint material. Cells grew on some of the artificial matrix materials, depending on the

  14. Microwave impregnation of porous materials with thermal energy storage materials

    SciTech Connect

    Benson, D.K.; Burrows, R.W.

    1991-03-13

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent tc the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  15. Microwave impregnation of porous materials with thermal energy storage materials

    SciTech Connect

    Benson, D.K.; Burrows, R.W.

    1992-12-31

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  16. Microwave impregnation of porous materials with thermal energy storage materials

    DOEpatents

    Benson, David K.; Burrows, Richard W.

    1993-01-01

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  17. Microwave impregnation of porous materials with thermal energy storage materials

    DOEpatents

    Benson, D.K.; Burrows, R.W.

    1993-04-13

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  18. Melding the Old with the New: Trends in Methods Used to Identify, Monitor, and Control Microorganisms on Cultural Heritage Materials.

    PubMed

    Sanmartín, Patricia; DeAraujo, Alice; Vasanthakumar, Archana

    2016-04-27

    Microbial activity has an important impact on the maintenance of cultural heritage materials, owing to the key role of microorganisms in many deterioration processes. In order to minimize such deleterious effects, there is a need to fine-tune methods that detect and characterize microorganisms. Trends in microbiology indicate that this need can be met by incorporating modern techniques. All of the methods considered in this review paper are employed in the identification, surveillance, and control of microorganisms, and they have two points in common: They are currently used in microbial ecology (only literature from 2009 to 2015 is included), and they are often applied in the cultural heritage sector. More than 75 peer-reviewed journal articles addressing three different approaches were considered: molecular, sensory and morphological, and biocontrol methods. The goal of this review is to highlight the usefulness of the traditional as well as the modern methods. The general theme in the literature cited suggests using an integrated approach.

  19. ATS materials support

    SciTech Connect

    Karnitz, M.A.; Wright, I.G.; Ferber, M.K.; Holcomb, R.S.; Rawlins, M.H.

    1996-12-31

    The technology based portion of the Advanced Turbine System Program (ATS) contains several subelements which address generic technology issues for land-base gas turbine systems. One subelement is the Materials/Manufacturing Technology Program which is coordinated by DOE-Oak Ridge Operations and Oak Ridge National laboratory (ORNL) for the Department of Energy. The work in this subelement is being performed predominantly by industry with assistance from national laboratories and universities. Projects in this subelement are aimed toward hastening the incorporation of new materials and components in gas turbines. The materials manufacturing subelement was developed with input from gas turbine manufacturers, material suppliers, government laboratories and universities. Work is currently ongoing on thermal barrier coatings (TBCs), the scale-up of single-crystal airfoil manufacturing technologies, materials characterization and technology information exchange. Westinghouse Power Generation and Pratt and Whitney each have material programs to develop dependable TBCs that enable increased turbine inlet temperatures while maintaining airfoil substrate temperatures at levels to meet the ATS life goals. Howmet and PCC Airfoils each have projects to extend the capability of single-crystal complex-cored airfoil technology to larger sizes so that higher turbine inlet temperatures can be attained in land-based turbines in a cost-effective manner. Materials characterization tasks are ongoing on TBCs in support of the industrial projects. In addition, a project on long-term testing of ceramics and ceramic-matrix composites for gas turbines is being conducted in support of programs at Solar Turbines, Allison Engines, and Westinghouse Power Generation.

  20. BUILDING MATERIALS RECLAMATION PROGRAM

    SciTech Connect

    David C. Weggel; Shen-En Chen; Helene Hilger; Fabien Besnard; Tara Cavalline; Brett Tempest; Adam Alvey; Madeleine Grimmer; Rebecca Turner

    2010-08-31

    This report describes work conducted on the Building Materials Reclamation Program for the period of September 2008 to August 2010. The goals of the project included selecting materials from the local construction and demolition (C&D) waste stream and developing economically viable reprocessing, reuse or recycling schemes to divert them from landfill storage. Educational resources as well as conceptual designs and engineering feasibility demonstrations were provided for various aspects of the work. The project was divided into two distinct phases: Research and Engineering Feasibility and Dissemination. In the Research Phase, a literature review was initiated and data collection commenced, an advisory panel was organized, and research was conducted to evaluate high volume C&D materials for nontraditional use; five materials were selected for more detailed investigations. In the Engineering Feasibility and Dissemination Phase, a conceptual study for a regional (Mecklenburg and surrounding counties) collection and sorting facility was performed, an engineering feasibility project to demonstrate the viability of recycling or reuse schemes was created, the literature review was extended and completed, and pedagogical materials were developed. Over the two-year duration of the project, all of the tasks and subtasks outlined in the original project proposal have been completed. The Final Progress Report, which briefly describes actual project accomplishments versus the tasks/subtasks of the original project proposal, is included in Appendix A of this report. This report describes the scientific/technical aspects (hypotheses, research/testing, and findings) of six subprojects that investigated five common C&D materials. Table 1 summarizes the six subprojects, including the C&D material studied and the graduate student and the faculty advisor on each subproject.