2,083 research outputs found

    Analysis of Minerals Using Specimen Isolated Secondary Ion Mass Spectrometry

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    Considerably improved suppression of molecular ions in secondary ion mass spectrometry (SIMS) spectra of nonconductor minerals has been obtained using a CAMECA IMS-3f ion microscope with unconventional operating conditions [so-called specimen isolated (SI) conditions]. In a zircon spectrum close to forty elements are positively identified and molecular ions such as oxides and hydrides have very low intensities. Thus, with a 28Si+ intensity of 106 cps, the Si+/Si0+ ratio is 105, and the 30SiH+ intensity is low enough to enable quantitative analysis using 31P+ down to 0.01 wt % P2O5 in a silicate glass matrix. The SI conditions enable us to follow major, minor and trace element concentrations across a complex alteration zone such as a sphene/hornblende contact. Isotope ratios show reasonable agreement with natural isotopic abundances, but relatively large kinetic energy induced isotopic fractionation is observed due to our analysis of high kinetic energy secondary ions. For zircon, and sphene samples, the isotope fractionation plotted against the mass ratios of the isotopes shows a linear dependence

    Predicting sexual problems in women: The relevance of sexual excitation and sexual inhibition

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    This is the post-print version of the article. The official published version can be obtained from the link below.Data from a non-clinical sample of 540 heterosexual women were used to examine the relationships between scores on the Sexual Excitation/Sexual Inhibition Inventory for Women (SESII-W) and ratings of current sexual problems, lifetime arousal difficulty, lifetime orgasm difficulty, and lifetime problems with low sexual interest. Multiple regression analyses also included several demographic/background variables as predictors: age, full-time employment, completed college, children in household, married, health ratings, importance of sex, and whether the woman was in a sexual relationship. The strongest statistical predictors of both current and lifetime sexual problems were the SESII-W inhibition factors Arousal Contingency and Concerns about Sexual Function. Demographic factors did not feature largely in any of the models predicting sexual problems even when statistically significant relationships were found. If future research supports the predictive utility of the SESII-W in identifying women who are more likely to experience sexual difficulties, these scales may be used as prognostic factors in treatment studies.This study was funded, in part, by a grant from the Lilly Centre for Women's Health

    High Energy Secondaries for the Quantitative Secondary Ion Mass Spectrometric Analysis of Minerals

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    The major hurdle in quantitative analysis by SIMS is the inconsistency and non-predictability of ion yields, particularly their sensitivity to sample matrix. High energy (100-500 eV) secondary ions have been shown to be considerably less susceptible to matrix effects than low energy secondary ions, particularly in mineral analysis. Therefore ion yields of some sixty elements were measured utilizing very high energy secondaries (~ 500 eV), from a standard silicate glass. They show a broad ionization potential dependence and a mass (or velocity) dependency which is not removed by the application of a M½ or M factor. The modification of yields with conventional thermodynamic partition functions, improves but does not clearly define agreement with the inverse exponential relationship observed by others, for low energy secondaries sputtered from oxygen rich matrices. The reproducibility of ion yields of high energy secondaries suggests empirical approaches to quantitative analysis are well justified; however the poor agreement of ion yields with an inverse exponential relationship, suggests that ion yielding mechanisms are somewhat different to those proposed in the low energy regime

    Spatially and genetically distinct African trypanosome virulence variants defined by host interferon-g response

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    We describe 2 spatially distinct foci of human African trypansomiasis in eastern Uganda. The Tororo and Soroti foci of <i>Trypanosoma brucei rhodesiense</i> infection were genetically distinct as characterized by 6 microsatellite and 1 minisatellite polymorphic markers and were characterized by differences in disease progression and host-immune response. In particular, infections with the Tororo genotype exhibited an increased frequency of progression to and severity of the meningoencephalitic stage and higher plasma interferon (IFN)–γ concentration, compared with those with the Soroti genotype. We propose that the magnitude of the systemic IFN-γ response determines the time at which infected individuals develop central nervous system infection and that this is consistent with the recently described role of IFN-γ in facilitating blood-brain barrier transmigration of trypanosomes in an experimental model of infection. The identification of trypanosome isolates with differing disease progression phenotypes provides the first field-based genetic evidence for virulence variants in T. <i>brucei rhodesiense</i>

    A classification of tasks for the systematic study of immune response using functional genomics data

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    A full understanding of the immune system and its responses to infection by different pathogens is important for the development of anti-parasitic vaccines. A growing number of large-scale experimental techniques, such as microarrays, are being used to gain a better understanding of the immune system. To analyse the data generated by these experiments, methods such as clustering are widely used. However, individual applications of these methods tend to analyse the experimental data without taking publicly available biological and immunological knowledge into account systematically and in an unbiased manner. To make best use of the experimental investment, to benefit from existing evidence, and to support the findings in the experimental data, available biological information should be included in the analysis in a systematic manner. In this review we present a classification of tasks that shows how experimental data produced by studies of the immune system can be placed in a broader biological context. Taking into account available evidence, the classification can be used to identify different ways of analysing the experimental data systematically. We have used the classification to identify alternative ways of analysing microarray data, and illustrate its application using studies of immune responses in mice to infection with the intestinal nematode parasites Trichuris muris and Heligmosomoides polygyrus

    Short report. The AIDIT and IMPACT conference 2006: Outcomes and future directions

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    IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls) is an international collaboration investigating the utility of targeted prostate-specific antigen (PSA) screening for men at increased risk of prostate cancer due to inherited predisposition. Although the majority of prostate cancer occurs sporadically, it is recognized that family history plays a role in a significant number of cases: a family history either of prostate cancer alone, or of other cancers including breast and ovarian cancer. Evidence of the link between single genes and prostate cancer risk is strongest for the BRCA1 and BRCA2 genes, with BRCA2 in particular thought to lead to a relative risk of 4.65 (95%CI 3.48-6.22). This relative risk may be as high as 7.33 in men under the age of 65 years

    Social Work with Children Affected by Domestic Violence: An Analysis of Policy and Practice Implications

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    The past decade has seen an increasing awareness of the emotional harm to children that can ensue from exposure to domestic violence. This article develops a framework for understanding social work responses, using an analysis of recent developments in British policy as an example. It is argued that to understand what these developments mean in practice we need to develop our analysis of the value perspectives underpinning them. Issues facing those charged with implementing these sometimes ambiguous policy and practice changes are discussed in three levels of intervention: the macro, the intermediate, and the 'street-level.' The article concludes by calling for closer collaboration between policy makers, practitioners and service users in the co-production of policy

    Signaling via interleukin-4, receptor alpha chain is required for successful vaccination against schistosomiasis in BALB/c mice

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    Radiation-attenuated (RA) schistosome larvae are potent stimulators of innate immune responses at the skin site of exposure (pinna) that are likely to be important factors in the development of Th1-mediated protective immunity. In addition to causing an influx of neutrophils, macrophages, and dendritic cells (DCs) into the dermis, RA larvae induced a cascade of chemokine and cytokine secretion following in vitro culture of pinna biopsy samples. While macrophage inflammatory protein 1 and interleukin-1 (IL-1) were produced transiently within the first few days, the Th1-promoting cytokines IL-12 and IL-18 were secreted at high levels until at least day 14. Assay of C3H/HeJ mice confirmed that IL-12 secretion was not due to lipopolysaccharide contaminants binding Toll-like receptor 4. Significantly, IL-12 p40 secretion was sustained in pinnae from vaccinated mice but not in those from nonprotected infected mice. In contrast, IL-10 was produced from both vaccinated and infected mice. This cytokine regulates IL-12-associated dermal inflammation, since in vaccinated IL-10/ mice, pinna thickness was greatly increased concurrent with elevated levels of IL-12 p40. A significant number of IL-12 p40 cells were detected as emigrants from in vitro-cultured pinnae, and most were within a population of rare large granular cells that were Ia, consistent with their being antigen-presenting cells. Labeling of IL-12 cells for CD11c, CD205, CD8, CD11b, and F4/80 indicated that the majority were myeloid DCs, although a proportion were CD11c F4/80, suggesting that macrophages were an additional source of IL-12 in the skin

    Asexuality: Classification and characterization

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    This is a post-print version of the article. The official published version can be obtaineed at the link below.The term “asexual” has been defined in many different ways and asexuality has received very little research attention. In a small qualitative study (N = 4), individuals who self-identified as asexual were interviewed to help formulate hypotheses for a larger study. The second larger study was an online survey drawn from a convenience sample designed to better characterize asexuality and to test predictors of asexual identity. A convenience sample of 1,146 individuals (N = 41 self-identified asexual) completed online questionnaires assessing sexual history, sexual inhibition and excitation, sexual desire, and an open-response questionnaire concerning asexual identity. Asexuals reported significantly less desire for sex with a partner, lower sexual arousability, and lower sexual excitation but did not differ consistently from non-asexuals in their sexual inhibition scores or their desire to masturbate. Content analyses supported the idea that low sexual desire is the primary feature predicting asexual identity

    Spectroscopy of 28^{28}Na: shell evolution toward the drip line

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    Excited states in 28^{28}Na have been studied using the β\beta-decay of implanted 28^{28}Ne ions at GANIL/LISE as well as the in-beam γ\gamma-ray spectroscopy at the NSCL/S800 facility. New states of positive (Jπ^{\pi}=3,4+^+) and negative (Jπ^{\pi}=1-5^-) parity are proposed. The former arise from the coupling between 0d_5/2\_{5/2} protons and a 0d_3/2\_{3/2} neutron, while the latter are due to couplings with 1p_3/2\_{3/2} or 0f_7/2\_{7/2} neutrons. While the relative energies between the Jπ^{\pi}=1-4+^+ states are well reproduced with the USDA interaction in the N=17 isotones, a progressive shift in the ground state binding energy (by about 500 keV) is observed between 26^{26}F and 30^{30}Al. This points to a possible change in the proton-neutron 0d_5/2\_{5/2}-0d_3/2\_{3/2} effective interaction when moving from stability to the drip line. The presence of Jπ^{\pi}=1-4^- negative parity states around 1.5 MeV as well as of a candidate for a Jπ^{\pi}=5^- state around 2.5 MeV give further support to the collapse of the N=20 gap and to the inversion between the 0f_7/2\_{7/2} and 1p_3/2\_{3/2} levels below Z=12. These features are discussed in the framework of Shell Model and EDF calculations, leading to predicted negative parity states in the low energy spectra of the 26^{26}F and 25^{25}O nuclei.Comment: Exp\'erience GANIL/LISE et NSCL/S80
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