bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Chorion Type on Genetic and Environmental Influences on Height, Weight, and Body Mass Index in South Korean Young Twins
Authors: Hur Yoon-Mi , Shin Jung-Sik 
Published: February 2008

AbstractThe present study examined the effects of chorionicity of twins on variations of height, weight, and body mass index (BMI) during childhood in the classical twin design. Mothers of 81 pairs of monochorionic monozygotic (MCMZ), 47 pairs of dichorionic monozygotic (DCMZ), and 457 pairs of dizygotic (DZ) twins drawn from the South Korean Twin Registry reported their children's height and weight. Twins' age ranged from 1.9 to 8.7 yrs, with a mean of 4.0 yrs and SD of 1.7 yrs. We computed maximum likelihood twin correlations and performed model-fitting analyses. In correlational and model-fitting analyses, we treated age and sex as covariates to control their main effects. Maximum likelihood MCMZ, DCMZ, and DZ twin correlations were, respectively, .96, .92, and .74, for height, .88, .91, and .57 for weight, and .93, .92, and .61 for BMI. The pattern of these twin correlations suggested very modest chorion effects on body measures. Model-fitting analyses confirmed the observations from twin correlations. Whereas genetic and shared environmental influences were significant for all three body measures, chorion effects attained statistical significance only for height (4%), and those for weight and BMI were zero. These findings indicate that genetic and environmental estimates for height, weight, and BMI during childhood are biased little by the chorion type of MZ twins, supporting the validity of the equal prenatal environment assumption in the classical twin design.
Factors Associated with Recent Increase of Multiple Births in Spain
Authors: Fuster Vicente , Zuluaga Pilar , Colantonio Sonia , de Blas Clemente 
Published: February 2008

AbstractThe increased incidence of multiple deliveries in Spain, in addition to changes in age at maternity and parity, is attributed to assisted reproductive treatments, but the relative contribution of the latter to this rise remains uncertain, due to the scarce information provided by clinics practicing those treatments. Population based data (1984–2004), including information on mother's age, nationality, marital status, date of delivery, and the characteristics of each (parity, single or multiple), and sex of newborns were provided by the Spanish Institute of Statistics. Twinning and triplet deliveries relate to maternal age, parity, and nationality. For younger ages (≤ 19, 20–24, 25–29) rates remained constant over time, but for older women (30–34, 35–39, ≥ 40) rates increased after 1994. From 1984 to 2004 the percentage of twins of opposite sex increased from 24.31 to 36.58 per cent. Since 1997, Spanish and non-Spanish mothers differentiate with respect to multiple maternity at ages over 30. In addition to unmarried Spanish women, immigrants constitute a reliable reference group that determines the convenience of segregating information on multiple deliveries respecting origin. The proportion of twins and triplets of opposite sex, maternal age, and parity patterns observed are concordant with a differential access to reproductive treatments depending on the woman's age. The present norm regulating the maximum number of fertilizations per cycle and the demand for these treatments explain the high incidence of multiple deliveries in Spain. A modified logistic curve predicts a stabilization of multiple deliveries, which will probably continue to be high in Spain.
Effect of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst.
Authors: Terziev Nasko , Daniel Geoffrey , Marklund Ann 
Published: February 2008

Abstract
The aim of the present study was to determine the effect of a variety of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst. Fibres representing abnormality were obtained from trees treated by irrigation and fertilisation. Moreover, fibres from compression wood and its accompanying opposite wood were isolated. The effect of dislocations on paper quality was studied on four mixtures (20, 40, 60 and 80% fibres with induced dislocations) of untreated/compressed fibres. Two more groups consisting of control untreated samples and samples with 100%-induced dislocations were also included in the test. The mechanical properties of the paper were tested and the results were compared to those of control samples. Abnormal fibres reduced the desired mechanical properties of the final paper concerning tensile strength, modulus of elasticity and tear-tensile index. Irrespective of the type of treatment, all morphological changes introduced in fibre cell walls appear to directly affect changes in the mechanical properties of the paper. Control samples had a tear index of 25 compared to 10 mN m2 g-1 of samples containing 100% dislocations. It is obvious that 20% of dislocations, an amount that is expected to be induced in pulp under mechanical processing and transport, will contribute to a decrease in tear index with an average of 3 mN m2 g-1, i.e., 10% of the total value.
Cellulose aerogels: Highly porous, ultra-lightweight materials
Authors: Liebner Falk , Potthast Antje , Rosenau Thomas , Haimer Emmerich , Wendland Martin 
Published: February 2008

Abstract
Cellulosic aerogels are intriguing new materials produced by supercritical drying of regenerated cellulose obtained by solvent exchange of solid Lyocell moldings. From N-methylmorpholine-N-oxide (NMMO) solutions with cellulose contents between 1 and 12%, dimensionally stable cellulose bodies are produced, in which the solution structure of the cellulose is largely preserved and transferred into the solid state, the material having densities down to 0.05 g cm-3 and surface areas of up to 280 m2 g-1. In this study, several aspects of cellulosic aerogel production are communicated: the stabilization of the cellulose solutions against degradation reactions by agents suitable for later extraction and drying, a reliable extraction and drying procedure by supercritical carbon dioxide, the advantages of DMSO/NMMO in this procedure as a solvent/non-solvent pair, and some data on the physical properties of the materials.
A generalized mat consolidation model for wood composites
Authors: Zhou Cheng , Dai Chunping , Smith Gregory D. 
Published: February 2008

Abstract
A generalized model for the prediction of mat pressure-density relationship of wood-based composites was developed. Based on the compression models for fiber assembly, this model treats the composite mat structure as a system of bending units, thus making element bending the dominant mechanism during early stage of mat consolidation. The consolidation behavior of fiber, strand, and particle mats were experimentally investigated. Satisfactory agreement was found between the model predictions and experimental results. Combined with the compression model, the entire strand mat consolidation can be predicted based on the properties of the wood constituents.
Conditional Switches for Extracellular Matrix Patterning inDrosophila melanogaster
Authors: Khokhar Arvinder , Chen Nan , Yuan Ji-Ping , Li Yishi , Landis Gary N , Beaulieu Gregory , Kaur Harminder , Tower John 
Published: February 2008

AbstractAn F1 mutagenesis strategy was developed to identify conditional mutations affecting extracellular matrix (ECM) patterning. Tubulogenesis requires coordinated movement of epithelial cells and deposition of a multilayered ECM. In the Drosophila ovary, an epithelium of follicle cells creates the eggshells, including the paired tubular dorsal appendages (DAs) that act as breathing tubes for the embryo. A P-element mutagenesis strategy allowed for conditional overexpression of hundreds of genes in follicle cells. Conditional phenotypes were scored at the level of individual mutant (F1) female flies. ECM pattern regulators were readily identified including MAPK signaling gene ets domain lacking (fused DAs), Wnt pathway genes frizzled 3 and osa (long DAs), Hh pathway gene debra (branched DAs), and transcription factor genes sima/HIF-1α, ush, lilli, Tfb1, broad, and foxo. In moving cells the [Ca2+]/calcineurin pathway can regulate adhesion to ECM while adherens junctions link cells together. Accordingly, thin eggshell and DA phenotypes were identified for the calcineurin regulator calreticulin and the adherens junction component arc. Finally a tubulogenesis defect phenotype was identified for the gene pterodactyl, homologous to the mammalian serine/threonine receptor-associated protein (STRAP) that integrates the TGF-β and PI3K/AKT signaling pathways. Because phenotypes can be scored in each mutant fly before and after gene induction, this F1 conditional mutagenesis strategy should allow for increased scale in screens for mutations affecting repeated (reiterated) events in adult animals, including gametogenesis, movement, behavior, and learning.
Genetic Evidence for Sites of Interaction Between the Gal3 and Gal80 Proteins of the Saccharomyces cerevisiae GAL Gene Switch
Authors: Diep Cuong Q , Tao Xiaorong , Pilauri Vepkhia , Losiewicz Mandy , Blank T Eric , Hopper James E 
Published: February 2008

Abstract
Galactose-activated transcription of the Saccharomyces cerevisiae GAL genes occurs when Gal3 binds the Gal4 inhibitor, Gal80. Noninteracting variants of Gal3 or Gal80 render the GAL genes noninducible. To identify the binding determinants for Gal3's interaction with Gal80 we carried out GAL3–GAL80 intergenic suppression analyses and selected for new GAL3 mutations that impair the Gal3–Gal80 interaction. We show that a GAL3C-D368V mutation can suppress the noninducibility due to a GAL80S-1-G323R mutation, and a GAL80-M350C mutation can suppress the noninducibility due to a gal3-D111C mutation. A reverse two-hybrid selection for GAL3 mutations that impair the Gal3–Gal80 interaction yielded 12 single-amino-acid substitutions at residues that are predicted to be surface exposed on Gal3. The majority of the affected Gal3 residues localized to a composite surface that includes D111 and a sequence motif containing D368, which has been implicated in interaction with Gal80. The striking colocalization of intergenic suppressor residues and Gal80 nonbinder residues identifies a Gal3 surface that likely interacts with Gal80.
The Glucose Transporter (GLUT4) Enhancer Factor Is Required for Normal Wing Positioning in Drosophila
Authors: Yazdani Umar , Huang Zhiyu , Terman Jonathan R 
Published: February 2008

Abstract
Many of the transcription factors and target genes that pattern the developing adult remain unknown. In the present study, we find that an ortholog of the poorly understood transcription factor, glucose transporter (GLUT4) enhancer factor (Glut4EF, GEF) [also known as the Huntington's disease gene regulatory region-binding protein (HDBP) 1], plays a critical role in specifying normal wing positioning in adult Drosophila. Glut4EF proteins are zinc-finger transcription factors named for their ability to regulate expression of GLUT4 but nothing is known of Glut4EF's in vivo physiological functions. Here, we identify a family of Glut4EF proteins that are well conserved from Drosophila to humans and find that mutations in Drosophila Glut4EF underlie the wing-positioning defects seen in stretch mutants. In addition, our results indicate that previously uncharacterized mutations in Glut4EF are present in at least 11 publicly available fly lines and on the widely used TM3 balancer chromosome. These results indicate that previous observations utilizing these common stocks may be complicated by the presence of Glut4EF mutations. For example, our results indicate that Glut4EF mutations are also present on the same chromosome as two gain-of-function mutations of the homeobox transcription factor Antennapedia (Antp) and underlie defects previously attributed to Antp. In fact, our results support a role for Glut4EF in the modulation of morphogenetic processes mediated by Antp, further highlighting the importance of Glut4EF transcription factors in patterning and morphogenesis.
Dominant Suppression of Repeat-Induced Point Mutation in Neurospora crassa by a Variant Catalytic Subunit of DNA Polymerase-ζ
Authors: Tamuli Ranjan , Kasbekar Durgadas P 
Published: February 2008

Abstract
Crosses involving the Adiopodoumé strain of Neurospora crassa are defective for repeat-induced point mutation (RIP), a genome defense mechanism of fungi. We show here that the Adiopodoumé strain possesses an incompletely penetrant and variably expressive dominant suppressor of RIP (Srp) that maps to an ∼34-kbp genome segment that is ∼26 kbp proximal to mat on linkage group IL. Gene disruption experiments revealed that Srp is the upr-1 allele of Adiopodoumé (upr-1Ad) that is contained within this segment. The upr-1 gene codes for the catalytic subunit of the translesion DNA polymerase-ζ (Pol-ζ) and it is unusually polymorphic in Neurospora. That the upr-1 gene contains upstream ORFs that overlap with the main ORF is potentially relevant to the incomplete penetrance and variable expressivity of the suppressor. Crosses between heterokaryons that contain upr-1Ad and strains that prevent mating events involving nuclei that contain upr-1Ad yielded no progeny in which RIP had occurred, consistent with the idea that the suppressor encoded by upr-1Ad is diffusible. The potential involvement of the Pol-ζ subunit in two functions, translesion DNA synthesis and RIP regulation, might account for the rapid evolution of its gene in Neurospora.
Comparison of Mixed-Model Approaches for Association Mapping
Authors: Stich Benjamin , Möhring Jens , Piepho Hans-Peter , Heckenberger Martin , Buckler Edward S , Melchinger Albrecht E 
Published: February 2008

Abstract
Association-mapping methods promise to overcome the limitations of linkage-mapping methods. The main objectives of this study were to (i) evaluate various methods for association mapping in the autogamous species wheat using an empirical data set, (ii) determine a marker-based kinship matrix using a restricted maximum-likelihood (REML) estimate of the probability of two alleles at the same locus being identical in state but not identical by descent, and (iii) compare the results of association-mapping approaches based on adjusted entry means (two-step approaches) with the results of approaches in which the phenotypic data analysis and the association analysis were performed in one step (one-step approaches). On the basis of the phenotypic and genotypic data of 303 soft winter wheat (Triticum aestivum L.) inbreds, various association-mapping methods were evaluated. Spearman's rank correlation between P-values calculated on the basis of one- and two-stage association-mapping methods ranged from 0.63 to 0.93. The mixed-model association-mapping approaches using a kinship matrix estimated by REML are more appropriate for association mapping than the recently proposed QK method with respect to (i) the adherence to the nominal α-level and (ii) the adjusted power for detection of quantitative trait loci. Furthermore, we showed that our data set could be analyzed by using two-step approaches of the proposed association-mapping method without substantially increasing the empirical type I error rate in comparison to the corresponding one-step approaches.
MultivariateQst–Fst Comparisons: A Neutrality Test for the Evolution of the G Matrix in Structured Populations
Authors: Martin Guillaume , Chapuis Elodie , Goudet Jérôme 
Published: February 2008

AbstractNeutrality tests in quantitative genetics provide a statistical framework for the detection of selection on polygenic traits in wild populations. However, the existing method based on comparisons of divergence at neutral markers and quantitative traits (Qst–Fst) suffers from several limitations that hinder a clear interpretation of the results with typical empirical designs. In this article, we propose a multivariate extension of this neutrality test based on empirical estimates of the among-populations (D) and within-populations (G) covariance matrices by MANOVA. A simple pattern is expected under neutrality: D = 2Fst/(1 − Fst)G, so that neutrality implies both proportionality of the two matrices and a specific value of the proportionality coefficient. This pattern is tested using Flury's framework for matrix comparison [common principal-component (CPC) analysis], a well-known tool in G matrix evolution studies. We show the importance of using a Bartlett adjustment of the test for the small sample sizes typically found in empirical studies. We propose a dual test: (i) that the proportionality coefficient is not different from its neutral expectation [2Fst/(1 − Fst)] and (ii) that the MANOVA estimates of mean square matrices between and among populations are proportional. These two tests combined provide a more stringent test for neutrality than the classic Qst–Fst comparison and avoid several statistical problems. Extensive simulations of realistic empirical designs suggest that these tests correctly detect the expected pattern under neutrality and have enough power to efficiently detect mild to strong selection (homogeneous, heterogeneous, or mixed) when it is occurring on a set of traits. This method also provides a rigorous and quantitative framework for disentangling the effects of different selection regimes and of drift on the evolution of the G matrix. We discuss practical requirements for the proper application of our test in empirical studies and potential extensions.
Functioning of the Drosophila Wilms'-Tumor-1-Associated Protein Homolog, Fl(2)d, in Sex-Lethal-Dependent Alternative Splicing
Authors: Penn Jill K M , Graham Patricia , Deshpande Girish , Calhoun Gretchen , Chaouki Ahmad Sami , Salz Helen K , Schedl Paul 
Published: February 2008

Abstractfl(2)d, the Drosophila homolog of Wilms'-tumor-1-associated protein (WTAP), regulates the alternative splicing of Sex-lethal (Sxl), transformer (tra), and Ultrabithorax (Ubx). Although WTAP has been found in functional human spliceosomes, exactly how it contributes to the splicing process remains unknown. Here we attempt to identify factors that interact genetically and physically with fl(2)d. We begin by analyzing the Sxl-Fl(2)d protein–protein interaction in detail and present evidence suggesting that the female-specific fl(2)d1 allele is antimorphic with respect to the process of sex determination. Next we show that fl(2)d interacts genetically with early acting general splicing regulators and that Fl(2)d is present in immunoprecipitable complexes with Snf, U2AF50, U2AF38, and U1-70K. By contrast, we could not detect Fl(2)d complexes containing the U5 snRNP protein U5-40K or with a protein that associates with the activated B spliceosomal complex SKIP. Significantly, the genetic and molecular interactions observed for Sxl are quite similar to those detected for fl(2)d. Taken together, our findings suggest that Sxl and fl(2)d function to alter splice-site selection at an early step in spliceosome assembly.
Independent Effects of cis- and trans-regulatory Variation on Gene Expression in Drosophila melanogaster
Authors: Wittkopp Patricia J , Haerum Belinda K , Clark Andrew G 
Published: February 2008

Abstract
Biochemical interactions between cis-regulatory DNA sequences and trans-regulatory gene products suggest that cis- and trans-acting polymorphisms may interact genetically. Here we present a strategy to test this hypothesis by comparing the relative cis-regulatory activity of two alleles in different genetic backgrounds. Of the eight genes surveyed in this study, five were affected by trans-acting variation that altered total transcript levels, two of which were also affected by differences in cis-regulation. The presence of trans-acting variation had no effect on relative cis-regulatory activity, showing that cis-regulatory polymorphisms can function independently of trans-regulatory variation. The frequency of such independent interactions on a genomic scale is yet to be determined.
Drop-Size Soda Lakes: Transient Microbial Habitats on a Salt-Secreting Desert Tree
Authors: Qvit-Raz Noga , Jurkevitch Edouard , Belkin Shimshon 
Published: February 2008

AbstractWe describe a hitherto unrecognized bacterial community, inhabiting the leaf surfaces of the salt-excreting desert tree Tamarix. High temperatures, strong radiation, and very low humidity dictate a daytime existence in complete desiccation, but damp nights allow the microbial population to proliferate in a sugar-rich, alkaline, and hypersaline solution, before drying up again after sunrise. The exclusively bacterial population contains many undescribed species and genera, but nevertheless appears to be characterized by relatively limited species diversity. Sequences of 16S rRNA genes from either isolates or total community DNA place the identified members of the community in five bacterial groups (Actinobacteria, Bacteroidetes, Firmicutes, α-, and γ-Proteobacteria); in each of these, they concentrate in a very narrow branch that in most cases harbors organisms isolated from unrelated halophilic environments.
Fine Haplotype Structure of a Chromosome 17 Region in the Laboratory and Wild Mouse
Authors: Trachtulec Zdenek , Vlcek Cestmir , Mihola Ondrej , Gregorova Sona , Fotopulosova Vladana , Forejt Jiri 
Published: February 2008

Abstract
Extensive linkage disequilibrium among classical laboratory strains represents an obstacle in the high-resolution haplotype mapping of mouse quantitative trait loci (QTL). To determine the potential of wild-derived mouse strains for fine QTL mapping, we constructed a haplotype map of a 250-kb region of the t-complex on chromosome 17 containing the Hybrid sterility 1 (Hst1) gene. We resequenced 33 loci from up to 80 chromosomes of five mouse (sub)species. Trans-species single-nucleotide polymorphisms (SNPs) were rare between Mus m. musculus (Mmmu) and Mus m. domesticus (Mmd). The haplotypes in Mmmu and Mmd differed and therefore strains from these subspecies should not be combined for haplotype-associated mapping. The haplotypes of t-chromosomes differed from all non-t Mmmu and Mmd haplotypes. Half of the SNPs and SN indels but only one of seven longer rearrangements found in classical laboratory strains were useful for haplotype mapping in the wild-derived M. m. domesticus. The largest Mmd haplotype block contained three genes of a highly conserved synteny. The lengths of the haplotype blocks deduced from 36 domesticus chromosomes were in tens of kilobases, suggesting that the wild-derived Mmd strains are suitable for fine interval-specific mapping.