5,860 research outputs found

    Reaction of Group III Biheterocyclic Complexes

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    Group III alkyl complexes supported by a ferrocene diamide ligand (1,1′-fc(NSitBuMe_2)_2) have been found to be reactive toward aromatic N-heterocycles such as 1-methylimidazole and pyridines. These reactions were investigated experimentally and computationally. An initial C−H activation event is followed by a coupling reaction to form biheterocyclic complexes, in which one of the rings is dearomatized. In the case of 1-methylimidazole, the biheterocyclic compound could not be isolated and further led to an imidazole ring-opened product; in the case of pyridines, it transformed into an isomer with extended conjugation of double bonds. Mechanisms for both reactions are proposed on the basis of experimental and computational results. DFT calculations were also used to show that an energetically accessible pathway for the ring-opening of pyridines exists

    Research and Development of Automated Eddy Current Testing for Composite Overwrapped Pressure Vessels

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    Eddy current testing (ET) was used to scan bare metallic liners used in the fabrication of composite overwrapped pressure vessels (COPVs) for flaws which could result in premature failure of the vessel. The main goal of the project was to make improvements in the areas of scan signal to noise ratio, sensitivity of flaw detection, and estimation of flaw dimensions. Scan settings were optimized resulting in an increased signal to noise ratio. Previously undiscovered flaw indications were observed and investigated. Threshold criteria were determined for the system software's flaw report and estimation of flaw dimensions were brought to an acceptable level of accuracy. Computer algorithms were written to import data for filtering and a numerical derivative filtering algorithm was evaluated

    Cumulative and Differential Effects of Early Child Care and Middle Childhood Out-of-School Time on Adolescent Functioning.

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    Effects associated with early child care and out-of-school time (OST) during middle childhood were examined in a large sample of U.S. adolescents (N = 958). Both higher quality early child care AND more epochs of organized activities (afterschool programs and extracurricular activities) during middle childhood were linked to higher academic achievement at age 15. Differential associations were found in the behavioral domain. Higher quality early child care was associated with fewer externalizing problems, whereas more hours of early child care was linked to greater impulsivity. More epochs of organized activities was associated with greater social confidence. Relations between early child care and adolescent outcomes were not mediated or moderated by OST arrangements in middle childhood, consistent with independent, additive relations of these nonfamilial settings

    Exchange-coupling constants, spin density map, and Q dependence of the inelastic neutron scattering intensity in single-molecule magnets

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    The Q dependence of the inelastic neutron scattering (INS) intensity of transitions within the ground-state spin multiplet of single-molecule magnets (SMMs) is considered. For these transitions, the Q dependence is related to the spin density map in the ground state, which in turn is governed by the Heisenberg exchange interactions in the cluster. This provides the possibility to infer the exchange-coupling constants from the Q dependence of the INS transitions within the spin ground state. The potential of this strategy is explored for the M = +-10 -> +- 9 transition within the S = 10 multiplet of the molecule Mn12 as an example. The Q dependence is calculated for powder as well as single-crystal Mn12 samples for various exchange-coupling situations discussed in the literature. The results are compared to literature data on a powder sample of Mn12 and to measurements on an oriented array of about 500 single-crystals of Mn12. The calculated Q dependence exhibits significant variation with the exchange-coupling constants, in particular for a single-crystal sample, but the experimental findings did not permit an unambiguous determination. However, although challenging, suitable experiments are within the reach of today's instruments.Comment: 11 pages, 6 figures, REVTEX4, to appear in PR

    Negative affect and ruminative self-focus during everyday goal pursuit

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    Models of self-regulation propose that negative affect is generated when progress towards goals is perceived to be inadequate. Similarly, ruminative thinking is hypothesised to be triggered by unattained goals (Martin & Tesser, 1996). We conducted an experience-sampling study in which participants recorded their negative affect, ruminative self-focus, and goal appraisals eight times daily for one week. Negative affect and ruminative self-focus were each associated with low levels of goal success and (with the exception of sadness) high levels of goal importance. As predicted, the combination of low goal success and high goal importance was associated with the highest levels of negative affect, and this interaction was marginally significant for ruminative self-focus. Decomposition of the ruminative self-focus measure revealed that the success by importance interaction was significantly associated with focus on problems but not focus on feelings. Findings did not differ for individuals reporting high versus low levels of depressive symptoms or trait rumination. These results suggest that self-regulatory models of goal pursuit provide a useful explanatory framework for the study of affect and ruminative thinking in everyday life

    Annotation of two large contiguous regions from the Haemonchus contortus genome using RNA-seq and comparative analysis with Caenorhabditis elegans

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    The genomes of numerous parasitic nematodes are currently being sequenced, but their complexity and size, together with high levels of intra-specific sequence variation and a lack of reference genomes, makes their assembly and annotation a challenging task. Haemonchus contortus is an economically significant parasite of livestock that is widely used for basic research as well as for vaccine development and drug discovery. It is one of many medically and economically important parasites within the strongylid nematode group. This group of parasites has the closest phylogenetic relationship with the model organism Caenorhabditis elegans, making comparative analysis a potentially powerful tool for genome annotation and functional studies. To investigate this hypothesis, we sequenced two contiguous fragments from the H. contortus genome and undertook detailed annotation and comparative analysis with C. elegans. The adult H. contortus transcriptome was sequenced using an Illumina platform and RNA-seq was used to annotate a 409 kb overlapping BAC tiling path relating to the X chromosome and a 181 kb BAC insert relating to chromosome I. In total, 40 genes and 12 putative transposable elements were identified. 97.5% of the annotated genes had detectable homologues in C. elegans of which 60% had putative orthologues, significantly higher than previous analyses based on EST analysis. Gene density appears to be less in H. contortus than in C. elegans, with annotated H. contortus genes being an average of two-to-three times larger than their putative C. elegans orthologues due to a greater intron number and size. Synteny appears high but gene order is generally poorly conserved, although areas of conserved microsynteny are apparent. C. elegans operons appear to be partially conserved in H. contortus. Our findings suggest that a combination of RNA-seq and comparative analysis with C. elegans is a powerful approach for the annotation and analysis of strongylid nematode genomes

    Hemin as a generic and potent protein misfolding inhibitor

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    Abstract not availableYanqin Liu, John A. Carver, Lam H. Ho, Abigail K. Elias, Ian F. Musgrave, Tara L. Pukal

    A systematic review of the relationship between rigidity/flexibility and transdiagnostic cognitive and behavioral processes that maintain psychopathology

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    An ever-growing number of transdiagnostic processes that maintain psychopathology across disorders have been identified. However, such processes are not consistently associated with psychological distress and symptoms. An understanding of what makes such processes pathological is required. One possibility is that individual differences in rigidity in the implementation of these processes determine the degree of psychopathology. The aim of this article is to examine the relationship between rigidity/flexibility and transdiagnostic maintenance processes. Initial searches were made for research examining relationships between 18 transdiagnostic processes and rigidity/flexibility. Relationships between rumination, perfectionism, impulsivity and compulsivity, and rigidity/flexibility were systemically reviewed; 50 studies met inclusion criteria. The majority of studies indicated that transdiagnostic cognitive and behavioral maintenance processes and rigidity were correlated, co-occurring, or predictive of each other. Findings are consistent with the hypothesis that it is inflexibility in the manner in which processes are employed that makes them pathologically problematic. However, further research is required to test and establish this

    Association between canine leishmaniosis and Ehrlichia canis co-infection: a prospective case-control study

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    Abstract Background In the Mediterranean basin, Leishmania infantum is a major cause of disease in dogs, which are frequently co-infected with other vector-borne pathogens (VBP). However, the associations between dogs with clinical leishmaniosis (ClinL) and VBP co-infections have not been studied. We assessed the risk of VBP infections in dogs with ClinL and healthy controls. Methods We conducted a prospective case-control study of dogs with ClinL (positive qPCR and ELISA antibody for L. infantum on peripheral blood) and clinically healthy, ideally breed-, sex- and age-matched, control dogs (negative qPCR and ELISA antibody for L. infantum on peripheral blood) from Paphos, Cyprus. We obtained demographic data and all dogs underwent PCR on EDTA-blood extracted DNA for haemoplasma species, Ehrlichia/Anaplasma spp., Babesia spp., and Hepatozoon spp., with DNA sequencing to identify infecting species. We used logistic regression analysis and structural equation modelling (SEM) to evaluate the risk of VBP infections between ClinL cases and controls. Results From the 50 enrolled dogs with ClinL, DNA was detected in 24 (48%) for Hepatozoon spp., 14 (28%) for Mycoplasma haemocanis, 6 (12%) for Ehrlichia canis and 2 (4%) for Anaplasma platys. In the 92 enrolled control dogs, DNA was detected in 41 (45%) for Hepatozoon spp., 18 (20%) for M. haemocanis, 1 (1%) for E. canis and 3 (3%) for A. platys. No Babesia spp. or “Candidatus Mycoplasma haematoparvum” DNA was detected in any dog. No statistical differences were found between the ClinL and controls regarding age, sex, breed, lifestyle and use of ectoparasitic prevention. A significant association between ClinL and E. canis infection (OR = 12.4, 95% CI: 1.5–106.0, P = 0.022) was found compared to controls by multivariate logistic regression. This association was confirmed using SEM, which further identified that younger dogs were more likely to be infected with each of Hepatozoon spp. and M. haemocanis, and dogs with Hepatozoon spp. were more likely to be co-infected with M. haemocanis. Conclusions Dogs with ClinL are at a higher risk of co-infection with E. canis than clinically healthy dogs. We recommend that dogs diagnosed with ClinL should be tested for E. canis co-infection using PCR
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