bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of interface effects on the rocking behaviour of graphite blocks
Authors: Holmes C , Drinkwater B. W , Payne J. F. B 
Published: January 2005

Large assemblies of blocks are common in many civil engineering structures such as dams, costal defences and ancient buildings. Such assemblies are also found in graphite cored nuclear reactors. These consist of large graphite bricks, which are used to moderate the reaction and are assembled in arrays up to 10m in height and 10m in diameter. In this paper, the bricks considered are 200mm x 200mm x 800mm. The seismic response of such a structure is dependent on both the properties of the bulk material and the nature of the interface between individual bricks. The bricks are in dry contact with those above and below, and it is this contacting interface that governs the rocking behaviour, which is therefore an important factor in assessing the response of the columns to vibration or a seismic event. This paper describes an investigation into the effect of microscopic and macroscopic surface features on the rocking behaviour of a single graphite brick. Typical real surfaces exhibit some form of macroscopic waviness in addition to the microscopic roughness and therefore only a small fraction of the surfaces are in contact. A number of analytical models are used to compare the effects of specific surface features with experimental data from real bricks. These models are compared with experimental results to assess their importance in explaining the rocking behaviour observed experimentally. Factors such as surface curvature, contact size and position are shown to be particularly important to the rocking stiffness of a brick. In most cases, the reduction in the rocking stiffness compared to perfectly flat surfaces is due to both the reduced moment arm of the contact forces and the increased strain at the contact region due to the high stress caused by the small area of contact.
Effect of alpha irradiation on UO2 surface reactivity in aqueous media
Authors: Jégou Christophe , Muzeau B. , Broudic V. , Poulesquen A. , Roudil Danièle , Jorion F. , Corbel C. 
Published: February 2005

Abstract
The option of direct disposal of spent nuclear fuel in a deep geological formation raises the need to investigate the long-term behavior of the UO2 matrix in aqueous media subjected to α-β-γ radiation. The β-γ emitters account for most of the activity of spent fuel at the moment it is removed from the reactor, but diminish within a millennial time frame by over three orders of magnitude to less than the long-term activity. The latter persists over much longer time periods and must therefore be taken into account over a geological disposal time scale. Leaching experiments with solution renewal were carried out on UO2 pellets doped with alpha emitters (238Pu and 239Pu) to quantify the impact of alpha irradiation on UO2 matrix alteration. Three batches of doped UO2 pellets with different alpha flux levels (3.30×104, 3.30×105, and 3.2×106 α cm-2 s-1) were studied. The results obtained in aerated and deaerated media immediately after sample annealing or interim storage in air provide a better understanding of the UO2 matrix alteration mechanisms under alpha irradiation.
Interim storage in air of UO2 pellets doped with alpha emitters results in variations of the UO2 surface reactivity, which depends on the alpha particle flux at the interface and on the interim storage duration. The variation in the surface reactivity and the greater uranium release following interim storage cannot be attributed to the effect of alpha radiolysis in aerated media since the uranium release tends toward the same value after several leaching cycles for the doped UO2 pellet batches and spent fuel. Oxygen diffusion enhanced by alpha irradiation of the extreme surface layer and/or radiolysis of the air could account for the oxidation of the surface UO2 to UO2+x. However, leaching experiments performed in deaerated media after annealing the samples and preleaching the surface suggest that alpha radiolysis does indeed affect the dissolution, which varies with the flux at the UO2/water interface.
Drosophila couch potato Mutants Exhibit Complex Neurological Abnormalities Including Epilepsy Phenotypes
Authors: Glasscock Edward , Tanouye Mark A 
Published: February 2005

Abstract
RNA-binding proteins play critical roles in regulation of gene expression, and impairment can have severe phenotypic consequences on nervous system function. We report here the discovery of several complex neurological phenotypes associated with mutations of couch potato (cpo), which encodes a Drosophila RNA-binding protein. We show that mutation of cpo leads to bang-sensitive paralysis, seizure susceptibility, and synaptic transmission defects. A new cpo allele called cpoEG1 was identified on the basis of a bang-sensitive paralytic mutant phenotype in a sensitized genetic background (sda/+). In heteroallelic combinations with other cpo alleles, cpoEG1 shows an incompletely penetrant bang-sensitive phenotype with ∼30% of flies becoming paralyzed. In response to electroconvulsive shock, heteroallelic combinations with cpoEG1 exhibit seizure thresholds less than half that of wild-type flies. Finally, cpo flies display several neurocircuit abnormalities in the giant fiber (GF) system. The TTM muscles of cpo mutants exhibit long latency responses coupled with decreased following frequency. DLM muscles in cpo mutants show drastic reductions in following frequency despite exhibiting normal latency relationships. The labile sites appear to be the electrochemical GF-TTMn synapse and the chemical PSI-DLMn synapses. These complex neurological phenotypes of cpo mutants support an important role for cpo in regulating proper nervous system function, including seizure susceptibility.
Adaptive Molecular Evolution for 13,000 Phage Generations
Authors: Wichman Holly A , Millstein Jack , Bull J J 
Published: February 2005

Abstract
Bacteriophage φX174 was evolved on a continuous supply of sensitive hosts for 180 days (∼13,000 phage generations). The average rate of nucleotide substitution was nearly 0.2% (11 substitutions)/20 days, and, surprisingly, substitutions accumulated in a clock-like manner throughout the study, except for a low rate during the first 20 days. Rates of silent and missense substitutions varied over time and among genes. Approximately 40% of the 71 missense changes and 25% of the 58 silent changes have been observed in previous adaptations; the rate of parallel substitution was highest in the early phase of the evolution, but 7% of the later changes had evolved in previous studies of much shorter duration. Several lines of evidence suggest that most of the changes were adaptive, even many of the silent substitutions. The sustained, high rate of adaptive evolution for 180 days defies a model of adaptation to a constant environment. We instead suggest that continuing molecular evolution reflects a potentially indefinite arms race, stemming from high levels of co-infection and the resulting conflict among genomes competing within the same cell.
Suppression of an Atypically Spliced Rice CACTA Transposon Transcript in Transgenic Plants
Authors: Greco Raffaella , Ouwerkerk Pieter B F , Pereira Andy 
Published: February 2005

AbstractOsES1, a rice homolog of the maize En/Spm transposon, is transcribed to produce TnpA-like and TnpD-like transcripts. However, an alternatively spliced form of the TnpA-like transcript, which was found to be suppressed in transgenic plants, was revealed to be due to atypical splicing of a Hipa-like CACTA transposon.
Genetic Architecture of Transcript-Level Variation in Differentiating Xylem of a Eucalyptus Hybrid
Authors: Kirst Matias , Basten Christopher J , Myburg Alexander A , Zeng Zhao-Bang , Sederoff Ronald R 
Published: February 2005

Abstract
Species diversity may have evolved by differential regulation of a similar set of genes. To analyze and compare the genetic architecture of transcript regulation in different genetic backgrounds of Eucalyptus, microarrays were used to examine variation in mRNA abundance in the differentiating xylem of a E. grandis pseudobackcross population [E. grandis × F1 hybrid (E. grandis × E. globulus)]. Least-squares mean estimates of transcript levels were generated for 2608 genes in 91 interspecific backcross progeny. The quantitative measurements of variation in transcript abundance for specific genes were mapped as expression QTL (eQTL) in two single-tree genetic linkage maps (F1 hybrid paternal and E. grandis maternal). EQTL were identified for 1067 genes in the two maps, of which 811 were located in the F1 hybrid paternal map, and 451 in the E. grandis maternal map. EQTL for 195 genes mapped to both parental maps, the majority of which localized to nonhomologous linkage groups, suggesting trans-regulation by different loci in the two genetic backgrounds. For 821 genes, a single eQTL that explained up to 70% of the transcript-level variation was identified. Hotspots with colocalized eQTL were identified in both maps and typically contained genes associated with specific metabolic and regulatory pathways, suggesting coordinated genetic regulation.
Genetic Bases of Estrogen-Induced Pituitary Tumorigenesis
Authors: Strecker Tracy E , Spady Thomas J , Schaffer Beverly S , Gould Karen A , Kaufman Amy E , Shen Fangchen , McLaughlin Mac T , Pennington Karen L , Meza Jane L , Shull James D 
Published: February 2005

AbstractEstrogens stimulate proliferation and enhance survival of the prolactin (PRL)-producing lactotroph of the anterior pituitary gland and induce development of PRL-producing pituitary tumors in certain inbred rat strains but not others. The goal of this study was to elucidate the genetic bases of estrogen-induced pituitary tumorigenesis in reciprocal intercrosses between the genetically related ACI and Copenhagen (COP) rat strains. Following 12 weeks of treatment with the synthetic estrogen diethylstilbestrol (DES), pituitary mass, an accurate surrogate marker of absolute lactotroph number, was increased 10.6-fold in ACI rats and 4.5-fold in COP rats. Composite interval mapping analyses of the phenotypically defined F2 progeny from the reciprocal crosses identified six quantitative trait loci (QTL) that determine the pituitary growth response to DES. These loci reside on chromosome 6 [Estrogen-induced pituitary tumor (Ept)1], chromosome 3 (Ept2 and Ept6), chromosome 10 (Ept9), and chromosome 1 (Ept10 and Ept13). Together, these six Ept loci and one additional suggestive locus on chromosome 4 account for an estimated 40% of the phenotypic variance exhibited by the combined F2 population, while 34% of the phenotypic variance was estimated to result from environmental factors. These data indicate that DES-induced pituitary mass behaves as a quantitative trait and provide information that will facilitate identification of genes that determine the tumorigenic response of the pituitary gland to estrogens.
The Rad1-Rad10 Complex Promotes the Production of Gross Chromosomal Rearrangements From Spontaneous DNA Damage in Saccharomyces cerevisiae
Authors: Hwang Ji-Young , Smith Stephanie , Myung Kyungjae 
Published: February 2005

Abstract
Gross chromosomal rearrangements (GCRs) have been observed in many cancers. Previously, we have demonstrated many mechanisms for suppression of GCR formation in yeast. However, pathways that promote the formation of GCRs are not as well understood. Here, we present evidence that the Rad1-Rad10 endonuclease, which plays an important role in nucleotide excision and recombination repairs, has a novel role to produce GCRs. A mutation of either the RAD1 or the RAD10 gene reduced GCR rates in many GCR mutator strains. The inactivation of Rad1 or Rad10 in GCR mutator strains also slightly enhanced methyl methanesulfonate sensitivity. Although the GCRs induced by treatment with DNA-damaging agents were not reduced by rad1 or rad10 mutations, the translocation- and deletion-type GCRs created by a single double-strand break are mostly replaced by de novo telomere-addition-type GCR. Results presented here suggest that Rad1-Rad10 functions at different stages of GCR formation and that there is an alternative pathway for the GCR formation that is independent of Rad1-Rad10.
Autosomal Genes of Autosomal/X-Linked Duplicated Gene Pairs and Germ-Line Proliferation in Caenorhabditis elegans
Authors: Maciejowski John , Ahn James Hyungsoo , Cipriani Patricia Giselle , Killian Darrell J , Chaudhary Aisha L , Lee Ji Inn , Voutev Roumen , Johnsen Robert C , Baillie David L , Gunsalus Kristin C , Fitch David H A , Hubbard E Jane Albert 
Published: February 2005

Abstract
We report molecular genetic studies of three genes involved in early germ-line proliferation in Caenorhabditis elegans that lend unexpected insight into a germ-line/soma functional separation of autosomal/X-linked duplicated gene pairs. In a genetic screen for germ-line proliferation-defective mutants, we identified mutations in rpl-11.1 (L11 protein of the large ribosomal subunit), pab-1 [a poly(A)-binding protein], and glp-3/eft-3 (an elongation factor 1-α homolog). All three are members of autosome/X gene pairs. Consistent with a germ-line-restricted function of rpl-11.1 and pab-1, mutations in these genes extend life span and cause gigantism. We further examined the RNAi phenotypes of the three sets of rpl genes (rpl-11, rpl-24, and rpl-25) and found that for the two rpl genes with autosomal/X-linked pairs (rpl-11 and rpl-25), zygotic germ-line function is carried by the autosomal copy. Available RNAi results for highly conserved autosomal/X-linked gene pairs suggest that other duplicated genes may follow a similar trend. The three rpl and the pab-1/2 duplications predate the divergence between C. elegans and C. briggsae, while the eft-3/4 duplication appears to have occurred in the lineage to C. elegans after it diverged from C. briggsae. The duplicated C. briggsae orthologs of the three C. elegans autosomal/X-linked gene pairs also display functional differences between paralogs. We present hypotheses for evolutionary mechanisms that may underlie germ-line/soma subfunctionalization of duplicated genes, taking into account the role of X chromosome silencing in the germ line and analogous mammalian phenomena.
Effects of Alcohol Intake During Pregnancy on Docosahexaenoic Acid and Arachidonic Acid in Umbilical Cord Vessels of Black Women
Authors: Beblo Skadi , Stark Ken D. , Murthy Mahadev , Janisse James , Rockett Helaine , Whitty Janice E. , Buda-Abela Michelle , Martier Susan S. , Sokol Robert J. , Hannigan John H. , Salem Norman 
Published: February 2005

Objective. Alcohol influences the intake and metabolism of several nutrients including long-chain polyunsaturated fatty acids (LC-PUFAs). The LC-PUFAs docosahexaenoic acid (DHA) and arachidonic acid (AA) are particularly crucial for intrauterine growth and brain development. We hypothesized that alcohol consumption adversely affects LC-PUFA levels in pregnant women and their newborn infants.
Methods. Pregnant black women (N = 208) presenting at a core city antenatal clinic were screened and recruited. Shortly before delivery, maternal plasma was collected. After delivery, umbilical arteries and veins were dissected from the cords, total lipids were extracted from the vessel tissues and maternal plasma, and fatty acid levels were assayed by gas chromatography. For statistical analysis, subjects were categorized according to absolute alcohol intake per day (AAD) and absolute alcohol intake per drinking day (AADD) around the time of conception, with smoking and other potential confounders included in the analyses.
Results. Significant differences in fatty acid composition of total lipid extracts were detected in umbilical cord vessels among the AADD groups: abstainers (AADD = 0), moderate drinkers (AADD &lt; 130 g), and heavy drinkers (AADD ≥ 130 g). DHA and AA content in the arterial umbilical vessel wall was ∼14% and ∼10% higher in the moderate (n = 127) and heavy (n = 32) alcohol groups, respectively, than in abstainers (n = 49). A small, nonsignificant increase (∼3%) was seen in the umbilical vein for AA but not for DHA. Alcohol intake was positively correlated to both DHA and AA concentrations in the arterial vessel wall but to neither in the venous wall nor maternal plasma. Maternal plasma DHA was positively correlated with both umbilical arteries and vein DHA, but there were no significant correlations for AA between maternal plasma and either umbilical vessel.
Conclusions. Our findings indicate that alcohol intake during pregnancy is associated with altered DHA and AA status in fetal tissues. Although differences may be due to either metabolism and/or distribution, it is most likely a result of a direct influence of alcohol on fetal metabolism.
Obesity and Renal Transplant Outcome: A Report of the North American Pediatric Renal Transplant Cooperative Study
Authors: Hanevold Coral D. , Ho Ping-Leung , Talley Lynya , Mitsnefes Mark M. 
Published: February 2005

Objective. Obesity is increasing in the end-stage renal disease population. Studies that have evaluated the effect of obesity on transplant outcomes in adults have yielded varying results. This issue has received little attention in the pediatric population.Methods. We performed a retrospective study of the effect of obesity on pediatric renal transplant outcomes using the North American Pediatric Renal Transplant Cooperative Study database. Registry data from 1987 through 2002 on 6658 children aged 2 to 17 years were analyzed. Obesity was defined by a BMI &gt;95th percentile for age.Results. Overall, 9.7% were obese with an increase noted in recent years (12.4% after 1995 vs 8% before 1995). Obese children were significantly younger and shorter and had been on dialysis for a longer time than nonobese children. There was no significant difference in the overall patient and allograft survival between the 2 groups. However, obese children aged 6 to 12 years had higher risk for death than nonobese patients (adjusted relative risk: 3.65 for living donor; adjusted relative risk: 2.94 for cadaver), and death was more likely as a result of cardiopulmonary disease (27% in obese vs 17% in nonobese). Overall, graft loss as a result of thrombosis was more common in obese as compared with nonobese (19% vs 10%).Conclusions. Obesity is an increasing problem in children who present for transplantation and may have an adverse effect on allograft and patient survival.
School Bullying and Suicidal Risk in Korean Middle School Students
Authors: Kim Young Shin , Koh Yun-Joo , Leventhal Bennett 
Published: February 2005

Objective. Being a victim or a perpetrator of school bullying, the most common type of school violence, has been frequently associated with a broad spectrum of behavioral, emotional, and social problems. In a Korean middle school community sample, this study specifically investigated the prevalence of suicidal ideations and behaviors in victims, perpetrators, and victim-perpetrators of school bullying and compared them with a group of students who were in the same schools and were not involved with bullying.Methods. In a cross-sectional study, 1718 seventh- and eighth-grade students in 2 middle schools participated in the study in October 2000. Students completed demographic information, Korean Peer Nomination Inventory, and Korean Youth Self-Report.Results. Compared with the students who were not involved with school bullying, victim-perpetrators reported more suicidal/self-injurious behaviors and suicidal ideation in the previous 6 months (odds ratio [OR]: 1.9 and 1.9, respectively). In female students, all 3 school bullying groups had increased suicidal ideation for the previous 2 weeks (OR: 2.8, 2.0, and 2.8, respectively) but not in male students (OR: 0.9, 1.1, and 1.3, respectively).Conclusions. Students who were involved in school bullying, especially victim-perpetrators and female students, had significantly higher risks for suicide ideation and suicidal behavior when compared with individuals who were not involved in school bullying. In addition to attempting to decrease bullying in a community, students who are involved in school bullying should be the targets for suicide monitoring and prevention programs.
Neuropsychological Functioning and Viral Load in Stable Antiretroviral Therapy-Experienced HIV-Infected Children
Authors: Jeremy Rita J. , Kim Soyeon , Nozyce Molly , Nachman Sharon , McIntosh Kenneth , Pelton Stephen I. , Yogev Ram , Wiznia Andrew , Johnson George M. , Krogstad Paul , Stanley Kenneth ,   for the Pediatric AIDS Clinical Trials Group (PACTG) 338 & 377 Study Teams
Published: February 2005

Objective. Neuropsychological functioning and its correlation with viral load were investigated for previously treated HIV-infected children who underwent a change in treatment regimen.Methods. Thirteen age-appropriate measures of cognitive, neurologic, and behavioral functioning were administered to 489 HIV-infected children who were aged 4 months to 17 years and had been treated previously for at least 16 weeks with antiretroviral therapy. These clinically and immunologically stable children were randomized onto 1 of 7 drug treatment combinations, 6 of which included a protease inhibitor (PI), and evaluated prospectively for 48 weeks with respect to changes in neuropsychological performance and viral load.Results. Neuropsychological functioning was significantly poorer at baseline for the HIV-infected children as compared with established norms for their age. Children with higher viral load had poorer cognitive, both-hands fine-motor, and neurologic signs at baseline, but single-hand fine-motor and behavioral functioning were not correlated with viral load. After 48 weeks of treatment with PI-containing combination therapy, there was significant improvement in only the vocabulary score. Neuropsychological changes did not differ among the 6 PI-containing combination regimens. At week 48, even children with a viral load response below the level of detection (RNA ≤400 copies/mL) still showed poorer neuropsychological functioning compared with established norms.Conclusion. Poor neuropsychological functioning was seen for HIV-infected children and was worse for children with higher viral loads. Only 1 measure of neuropsychological functioning showed improvement after treatment with PI-containing combination therapy, and the extent of that improvement was relatively minor. Treatment strategies for children with HIV disease need to be reevaluated so that they consider restoration of neuropsychological functioning in addition to lowering the viral load.
The Internet and Psychoactive Substance Use Among Innovative Drug Users
Authors: Boyer Edward W. , Shannon Michael , Hibberd Patricia L. 
Published: February 2005

Objective. The Internet contains an extraordinary amount of information on the recreational use of psychoactive substances. We investigated the effect of the Internet on the drug-use knowledge, attitudes, and behaviors of adolescents.Methods. Cross-sectional survey of adolescents being managed for substance abuse.Results. Of 12 patients (9 male, 3 female) who had used the Internet to learn about psychoactive substances, 100% reported that Internet-based information had affected the ways in which they had used psychoactive substances. Of the 12 respondents, 8 described adopting behaviors intended to minimize the risks associated with psychoactive substance use. Respondents also reported changes in the use of a wide variety of illicit substances as well as over-the-counter and prescription pharmaceuticals. Examiners assessed whether quotations demonstrated that respondents’ knowledge, attitudes, and behaviors toward psychoactive substance use were affected by Internet information. Despite the subjective nature of the research question, there was a highly significant agreement between coders.Conclusions. Web-based data on psychoactive substances seem to influence a broad range of drug-use behaviors in adolescents. Information on the ways that the Internet is being used by this vulnerable population should be considered in the design of Web sites to prevent the initiation and use of psychoactive substances.