bluuebunny/crossref_metadata_2025_split huggingface dataset:
QSAR Investigation of New Cognition Enhancers
Authors: Dearden John C. , Hewitt Mark , Geronikaki Athina A. , Garibova Taissia L. , Macaev Fliur Z. , Voronina Tatiana A. 
Published: September 2009

AbstractIncreasing longevity means that there is an increased likelihood of loss of cognitive functions and of incidence of dementias. There is thus a greater demand for cognition‐enhancing (noötropic) drugs. Some such drugs are already available, but many display serious side‐effects. We have designed, synthesized and tested a number of novel chemical entities that are predicted by the PASS software to be potential noötropic agents. The results have been subjected to QSAR (quantitative structure–activity relationship) analysis, and good QSAR correlations, with external validation, have been obtained, which can be used predictively to guide design of additional potential cognition‐enhancers.
Modelling the association between patient characteristics and the change over time in a disease measure using observational cohort data
Authors: Harrison L. , Dunn D. T. , Green H. , Copas A. J. 
Published: September 2009

AbstractIn observational cohort studies we may wish to examine the associations between fixed patient characteristics and the longitudinal changes from baseline in a repeated outcome measure. Many biological and other outcome measures are known to be subject to measurement error and biological variation. In an initial analysis we may fit a regression model to all outcome measurements, accounting for all the identified sources of variability, and see how the characteristics are linked to the change for typical patients. However, the characteristics may also be linked to different distributions of the underlying outcome value at baseline, which itself may be correlated with the change over time. Therefore, if we wish to examine the change over time for patients of different characteristics but with the same underlying baseline value then the initial approach is confounded by the baseline values. Furthermore, if we attempt to remove this confounding by including the observed baseline measure as a covariate in a model for later measurements, then this may provide an approximate solution but is likely to introduce some bias. We propose a method based on first following the initial approach but then, applying a correction to the parameter estimates. This allows the predicted trajectories to be plotted and valid significance tests of association with characteristics. Our approach is compared with other methods and illustrated through a simulation study and an analysis of the association between HIV‐1 subtype and immunological response after starting antiretroviral therapy. Copyright © 2009 John Wiley & Sons, Ltd.
Arsenic methylation capacity and its correlation with skin lesions induced by contaminated drinking water consumption in residents of chronic arsenicosis area
Authors: Li Xin , Li Bing , Xu Yuanyuan , Wang Yi , Jin Yaping , Itoh Toshihiro , Yoshida Takahiko , Sun Guifan 
Published: September 2009

AbstractChronic exposure to excess level of arsenic through contaminated drinking water is associated with many injuries, among which skin lesions are the most prominent. In this study, we measured the concentrations of inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in the blood of the residents of arsenicosis area, who demonstrated different skin lesion grade from mild, moderate to advanced. We evaluated the individual methylation capacity by two indices of the first and secondary methylation ratio (FMR and SMR). We found that SMR of moderate and advanced groups were markedly lower than that of mild group. Significant negative correlation was found between SMR of all the subjects and the grade of skin lesion, with Spearman's correlation coefficient of −0.429 (P = 0.016). Moreover, blood MMA proportion of moderate and advanced groups was found to be significantly higher than that of the mild group. These results suggest that low secondary arsenic methylation capacity and high MMA proportion are associated with the severity of arsenic‐related skin lesions. Our findings evaluated by blood speciation is consistent with that evaluated by the generally accepted urinary arsenic speciation in the relationship between arsenic methylation capacity and arsenic‐related lesions. © 2009 Wiley Periodicals, Inc. Environ Toxicol 26: 118–123, 2011.
Controlled Growth of Carbon Spheres Through the Mg-Reduction Route
Authors: Shi Liang , Lin Hailin , Bao Keyan , Cao Jie , Qian Yitai 
Published: September 2009

Abstract
Hollow spheres, hollow capsules and solid spheres of carbon were selectively synthesized by Mg-reduction of hexachlorobutadiene at appropriate reaction conditions. X-ray powder diffraction and Raman spectra reveal that the as-prepared materials have a well-ordered structure. A possible formation mechanism has been proposed.
Growth of InAs Quantum Dots on Germanium Substrate Using Metal Organic Chemical Vapor Deposition Technique
Authors: Dhawan Tanuj , Tyagi Renu , Bag RajeshKumar , Singh Mahavir , Mohan Premila , Haldar T , Murlidharan R , Tandon RP 
Published: September 2009

Abstract
Self-assembled InAs quantum dots (QDs) were grown on germanium substrates by metal organic chemical vapor deposition technique. Effects of growth temperature and InAs coverage on the size, density, and height of quantum dots were investigated. Growth temperature was varied from 400 to 450 °C and InAs coverage was varied between 1.40 and 2.35 monolayers (MLs). The surface morphology and structural characteristics of the quantum dots analyzed by atomic force microscope revealed that the density of the InAs quantum dots first increased and then decreased with the amount of InAs coverage; whereas density decreased with increase in growth temperature. It was observed that the size and height of InAs quantum dots increased with increase in both temperature and InAs coverage. The density of QDs was effectively controlled by growth temperature and InAs coverage on GaAs buffer layer.
Changes in Oil Content of Transgenic Soybeans Expressing the Yeast SLC1 Gene
Authors: Rao Suryadevara S. , Hildebrand David 
Published: September 2009

AbstractThe wild type (Wt) and mutant form of yeast (sphingolipid compensation) genes, SLC1 and SLC1‐1, have been shown to have lysophosphatidic acid acyltransferase (LPAT) activities (Nageic et al. in J Biol Chem 269:22156–22163, 1993). Expression of these LPAT genes was reported to increase oil content in transgenic Arabidopsis and Brassica napus. It is of interest to determine if the TAG content increase would also be seen in soybeans. Therefore, the wild type SLC1 was expressed in soybean somatic embryos under the control of seed specific phaseolin promoter. Some transgenic somatic embryos and in both T2 and T3 transgenic seeds showed higher oil contents. Compared to controls, the average increase in triglyceride values went up by 1.5% in transgenic somatic embryos. A maximum of 3.2% increase in seed oil content was observed in a T3 line. Expression of the yeast Wt LPAT gene did not alter the fatty acid composition of the seed oil.
RETRACTED ARTICLE: Missed Monteggia fracture in children: Is annular ligament reconstruction always required?
Authors: Bhaskar Atul 
Published: September 2009

Background Missed radio-capitellar joint dislocation is one of the feared complications of Monteggia fractures, especially when associated with subtle fractures of the ulna bone. Many treatment strategies have been described to manage the chronic Monteggia fracture and the need for annular ligament reconstruction is not always clear. This study is an attempt to address the issue of annular ligament reconstruction in the surgical management of missed Monteggia fracture. Materials and methods A retrospective study was performed in 12 patients who presented with missed Monteggia fracture. All children underwent open reduction of the radio-capitellar joint. Five children (Group A) were treated with ulna angulation–distraction osteotomy and annular ligament reconstruction, and six cases required only an ulna angulation–distraction osteotomy without ligament reconstruction. The duration of missed dislocation was from 3 to 18 months (mean 9 months). Ten patients were classified as Bado I, and one each as Bado II and III, respectively. Results The mean follow up period was 22 months. All ulna osteotomies healed uneventfully. The mean loss of pronation was 15° in Group A and 10° in Group B. Elbow flexion improved from the preoperative range and no child complained of pain, deformity and restriction of activity. In one case (Group A), there was 3 mm of radiographic subluxation of the radial head, but this child was clinically asymptomatic. The elbow score was excellent in ten cases and good in two cases. Conclusion Distraction–angulation osteotomy of the ulna suffices in most cases of missed Monteggia fracture and the need for annular ligament reconstruction is based on the intra-operative findings of radial head instability.
Inbreeding depression and heterosis of litter size in mice
Authors: Bowman J. C. , Falconer D. S. 
Published: September 2009

1. A random bred population of mice was subjected to inbreeding and the changes of litter size, measured as the number of live young in first litters, were followed.2. The mean litter size declined at a rate of 0·56 young per 10% increase of the inbreeding coefficient.3. Selection for large litters within the lines during the inbreeding did not effectively reduce the rate of decline.4. Out of twenty lines at the beginning of the inbreeding seventeen were lost by the time the inbreeding coefficient reached 76%. Two more were lost later and one survived indefinitely. The three lines that survived longest started at a level below the mean and did not decline in litter size. The one that survived indefinitely reached 99% inbreeding without dropping below the non-inbred control.5. The three lines surviving at 81% inbreeding were crossed and the litters produced by the crossbred progeny were larger than the non-inbred control by about two young per litter. This gain from heterosis is attributable to selection among the lines on their performance as inbreds. A second and third cycle of inbreeding and crossing yielded no further progress, and the level of the first cross was never regained. This is attributable to the ineffectiveness of the selection applied and to the previous restrictions of the population size.6. The behaviour of the lines in the inbreeding and crossing point to simple dominance rather than over-dominance at the loci causing variation of litter size.7. This experiment suggests that, as a means of improvement of farm animals, cyclical inbreeding and crossing does not look very hopeful.
Sexual dimorphism in mouse gametogenesis
Authors: Slizynski B. M. 
Published: September 2009

Diplotene and diakinesis chiasma frequency in oöcytes of the mouse cannot be studied successfully with the present technique. Metaphase chiasmata have been examined in thirty-nine oöcytes. It is deduced that the total diplotene map length in females is about 2300 cM. compared with 1950 cM. in males. There is sexual dimorphism in the frequency of chiasmata, which is paralleled by similar dimorphism in frequencies of crossing-over, measured genetically.The two sexes differ in the duration of various stages of meiosis. In adult males the pachytene stage, lasting for about 7 days, is directly followed by diplotene and diakinesis, after which the metaphase stage sets in. The sex bivalent in males develops visible chiasmata much earlier than do the autosomes and it precedes them in anaphase separation. Quick terminalization of chiasmata in it leads in a fair proportion of cases to precocious separation and in less than 1% of cases to cytologically detectable non-disjunction of sex chromosomes.In females the pachytene stage appears in oöcytes of the embryo and is followed by the dictyotene stage, which last still ovulation, i.e. between 35–40 days and several months. Since in the oöcyte chiasmata are formed and move during the dictyotene stage, it follows that stainable materials of the chromosomes are not necessary for the formation and movement of chiasmata and are concomitant with pairing and anaphase separation. It follows also that the time for chiasma formation and movement is in females at least five to six times longer than in males. In old oöcytes in which time is available for maximum terminalization of chiasmata, non-disjunction may appear with detectable frequency. This mechanism may also operate in cases of Mongolism in man, where non-disjunction of an autosome has been recently cytologically established and higher frequency of incidence of the condition for old mothers has been known for some time.It is possible that the differences in duration of various stages of gametogenesis are connected with the period at which gametic selection is operating: in spermatogenesis after the second meiotic division, in oögenesis prior to first meiotic metaphase.
Genic basis of the mate-killer trait inParamecium aurelia, stock 540
Authors: Gibson I. , Beale G. H. 
Published: September 2009

1. Stock 540 ofParamecium aurelia(syngen or variety 1) contains two duplicate genesM1andM2, each of which is capable of supporting growth of mu particles in the cytoplasm, thus producing the mate-killer phenotype.2. Of six sensitive stocks ofP. aureliasyngen 1, collected from widely separated localities, none contained eitherM1orM2.3. One sensitive stock (544), though proved to contain both recessive genesm1andm2, gave aberrant ratios of mate-killers and sensitives following hybridization with stock 540. Evidence has been adduced consistent with the hypothesis that them1- andm2-bearing chromosomes are involved in a translocation, by comparison with stock 540.4. There is a proportionality between numbers ofMgenes and speed of killing, and presumably therefore with the number of mu particles.5. Loss of mu particles following substitution ofMgenes by their recessive alleles occurs at times varying between eight and fifteen fissions after change of genotype.
Regular responses to selection I. Description of responses
Authors: Thoday J. M. , Boam T. B. 
Published: September 2009

1. Several lines of Drosophila melanogaster have been selected for increase of sternopleural chaeta-number.2. Three lines of the same origin, dp 1, dp 2 and dp 6, showed remarkably similar patterns of response involving an accelerated response from 24 to 28 chaetae and a plateau at about 30 chaetae. A line formed by crossing two of these was not responsive to selection, suggesting that the two parent lines were genetically similar.3. A fourth line, vg 4, related to these others, showed a similar accelerated response but continued to respond beyond 30 chaetae, reaching a plateau at about 37 chaetae.4. A further line, vg 6, set up by crossing two ‘improved’ lines, one with 30, the other with 22 chaetae, reached 46 chaetae and suggests there may sometimes be merit in selecting from the hybrids of ‘improved’ strains.5. It is argued that the event making possible the accelerated response is probably a recombinational event.6. The line vg 4 clearly demonstrates that some of the genes that may be exploited in a selection experiment have to be exploited in a particular order because of gene interactions.
Induced mitotic crossing-over inUstilago maydis
Authors: Holliday Robin 
Published: September 2009

1. Two different methods of selection were used to obtain stable prototrophic solopathogenic strains ofUstilago maydisfrom haploids with different biochemical requirements. The strains were shown to be heterozygous diploids.2. Two diploids which were examined in detail had four markers in common, but they were in different coupling and repulsion phases. Rare spontaneous segregation was detected in one of the diploids, but a high frequency of segregation was obtained in both after treatment with ultra-violet light. The proportion of segregants amongst the survivors increased with the dose. These auxotrophic segregants were detected by means of the replica plating technique.3. The types of segregant which were obtained from both diploids were consistent with the view that they arose as a result of mitotic crossing-over. After low doses of radiation the reciprocal products of crossing-over were often detected. There was no evidence from the phenotypes of the segregants that haploidization was occurring. The diploidy of a sample of the segregants was confirmed by mating-type tests, and by the fact that they showed further segregation after another dose of radiation.4. A slow-growing unstable segregant recovered after a high dose of radiation proved to be a monosomic strain which consistently reverted to a stable diploid homozygous for one chromosome. It was possible to use this auxotrophic diploid together with a haploid with different biochemical requirements, to synthesize a prototrophic triploid strain. The triploid was much less stable than the diploid strains.5. By means of pathogenicity tests with certain segregants it was possible to distinguish the function of the two loci which control the mating system. Thealocus is responsible for the fusion of haploid sporidia and has no effect on the pathogenicity of the heterokaryon which is under the control of theblocus.6. The effects of ultra-violet light on mitotic crossing-over do not seem to be easily compatible with a copy choice or similar mechanism of recombination.
Attachment of wild-typeFfactor to a specific chromosomal region in a variant strain ofEscherichia coliK12: the phenomenon of episomic alternation
Authors: Richter Alan 
Published: September 2009

A variant strain ofEscherichia coliK12 (♂3) was obtained after ultra-violet irradiation. This strain differs from wild type in the possession of a preferred chromosomal site for theFfactor.When wild-type females are infected with theFfactor they are converted toF+ males which carry theFfactor in the infectious state. TheseF+ males (standard) change with low frequency toHfrmales which carry theFfactor on the chromosome. When the variant female (♀3) is infected with theFfactor it is converted to anF+ male (state II) which changes with high frequency to a specificHfrmale (state I) which carries theFfactor at the preferred site (Hfr3).Male strains carrying the preferred site alternate between the specificHfrstate and theF+ state. The mechanism of this alternation is the back-and-forth shift of theFfactor between its integrated state of multiplication at theHfr3locus and its autonomous state of multiplication. This process is termedepisomic alternation.Episomic alternation offers a physical model for regular changes in state of the gene.TheHfr3locus has two allelic forms, high rate of change and standard rate of change. The allele for high rate of change may be considered as a genetic system which occurs in two possible states, state I in which theFfactor is present atHfr3, and state II in which it is not.
The genetics of fimbriation inEscherichia coli
Authors: Maccacaro G. A. , Hayes W. 
Published: September 2009

(1) Fimbriated cells ofE. coli K-12 are of two types. In the Fim+type the expression of fimbriation is susceptible to reversible environmental suppression. This type gives rise to environment-stable mutants termed Fimσ+.(2) Fimbriated cells can yield two types of non-fimbriated mutant, Fim−and Fimσ−, the latter arising from populations of Fimσ+cells. Neither type reverts to the fimbriated state.(3) Both types of fimbriated and non-fimbriated cells can be distinguished by physiological and genetic criteria.(4) Fimbriation of both types can be transferred to non-fimbriated cells of both types, and segregates among recombinants, in crosses mediated either by transduction or sexual conjugation.(5) The genetic control of fimbriation involves at least two determinants, for one of which a chromosomal location (fim) has been mapped.(6) Certain anomalies offimsegregation are interpreted in terms of negative interference over relatively large regions of the bacterial chromosome.
The quantitative relations between variation in red eye pigment and related pteridine compounds inDrosophila melanogaster
Authors: Barthelmess Ilse B. , Robertson Forbes W. 
Published: September 2009

SUMMARYThe relations between the quantity of red eye pigment and related pteridine compounds ofDrosophila melanogasterhave been studied in a variety of genotypes, which include strains selected for high or low pigment content, various derivatives of these lines and also lines in which one or other of the major autosome pairs were represented by homozygous chromosome pairs, derived by random sampling from the base population and also inbred lines. The quantity of red pigment was defined by the optical density when whole heads were extracted in a suitable solvent, while the pteridines were separated by chromatography and their amounts estimated by means of their characteristic fluorescence.The evidence from selection, inbreeding and chromosome sampling from the base population demonstrated the presence of substantial genetic variation for pigment content and amounts of related pteridines.The genetic and biochemical properties of the selected lines differed according to the direction of selection. High lines remained heterozygous after many generations of selection and displayed dominance and epistasis in favour of higher pigment content in crosses to the unselected stock. Selection for low pigment content led to fixation of recessive effects, attributable to particular chromosomes. The dominance-recessive relationship in red pigment differences was also applicable to the associated pteridines.The metabolic pattern in all lines with reduced pigment content is compatible with the assumption of reduced enzyme activity at particular steps of the pathway leading to the drosopterins (red eye pigments). The two steps accessible to study are subject to genetic variation in the base population, while inbreeding or selection for low pigment content leads to genetically fixed alterations at one or other of these steps. The genetic analysis was consistent with the biochemical evidence.Increase in pigment content above the normal level, either by selection or chance fixation, is accompanied by correlated increase in all the precursors. Several alternatives are possible but it is suggested that this may be due to an increase in early precursors, before the stages which have been altered in the low pigment lines.Attention is drawn to the similarity in genetic behaviour between pigment content and body size. Particular emphasis is laid on the value of selection as a means of creating biochemical differences which offer a basis for relating biochemical function and genetic behaviour.
Recombination events that span sites within neighbouring gene loci ofNeurospora
Authors: Murray Noreen E. 
Published: September 2009

SUMMARYEvidence is given thatme-7andme-9are separate but contiguous gene loci.The pattern of polarized recombination throughout theme-7 me-9region indicates the location of a recombinational discontinuity between the knownme-7alleles and the knownme-9alleles.Recombination events may include sites in both genes but such events are not preferentially associated with parental combinations of flanking markers.Recombination events extending into both genes provide an extra criterion for the ordering of the sites within theme-7locus. The order so obtained confirms that deduced from the flanking markers of me+recombinants fromme-7×me-7crosses.Inme-7×me-9crosses butnotinme-7×me-7crosses, the map order derived on the assumption that single exchanges are more frequent than apparent triple exchanges is the reverse of that derived from prototroph frequencies. It is concluded that the former criterion is more likely to have provided the correct order and the anomalous prototroph frequencies reflect the polarity of gene conversion withinme-7.