1,755 research outputs found

    Studies of Heart Development in Normal and Cardiac Lethal Mutant Axolotls: A Review

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    The morphology of developing hearts in axolotls, Ambystoma mexicanum, has been studied by scanning electron microscopy in order to provide a chronology of morphogenesis that can be correlated with ongoing biochemical and immunocytochemical studies. In addition to normal embryos we have studied homozygous recessive cardiac lethal mutant axolotls. The mutant myocardium undergoes aberrant sarcomere development and lacks a normal heartbeat. Morphogenesis of mutant hearts appears to be nearly normal with respect to myocardial cell shape changes, epicardial formation, and the distribution of extracellular matrix fibrils in the cardiac jelly. This suggests that the deficient arrangement of contractile proteins in mutant myocardial cells does not prevent the normal organization or function of cytoskeletal isoforms of these proteins in the developing myocardium and epicardium. The implications of biochemical and morphological investigations of axolotl hearts are considered in the context of the entire developmental history of the cardiogenic mesoderm

    Automated PGP9.5 immunofluorescence staining: a valuable tool in the assessment of small fiber neuropathy?

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    BACKGROUND: In this study we explored the possibility of automating the PGP9.5 immunofluorescence staining assay for the diagnosis of small fiber neuropathy using skin punch biopsies. The laboratory developed test (LDT) was subjected to a validation strategy as required by good laboratory practice guidelines and compared to the well-established gold standard method approved by the European Federation of Neurological Societies (EFNS). To facilitate automation, the use of thinner sections. (16 ”m) was evaluated. Biopsies from previously published studies were used. The aim was to evaluate the diagnostic performance of the LDT compared to the gold standard. We focused on technical aspects to reach high-quality standardization of the PGP9.5 assay and finally evaluate its potential for use in large scale batch testing. RESULTS: We first studied linear nerve fiber densities in skin of healthy volunteers to establish reference ranges, and compared our LDT using the modifications to the EFNS counting rule to the gold standard in visualizing and quantifying the epidermal nerve fiber network. As the LDT requires the use of 16 ”m tissue sections, a higher incidence of intra-epidermal nerve fiber fragments and a lower incidence of secondary branches were detected. Nevertheless, the LDT showed excellent concordance with the gold standard method. Next, the diagnostic performance and yield of the LDT were explored and challenged to the gold standard using skin punch biopsies of capsaicin treated subjects, and patients with diabetic polyneuropathy. The LDT reached good agreement with the gold standard in identifying small fiber neuropathy. The reduction of section thickness from 50 to 16 ”m resulted in a significantly lower visualization of the three-dimensional epidermal nerve fiber network, as expected. However, the diagnostic performance of the LDT was adequate as characterized by a sensitivity and specificity of 80 and 64 %, respectively. CONCLUSIONS: This study, designed as a proof of principle, indicated that the LDT is an accurate, robust and automated assay, which adequately and reliably identifies patients presenting with small fiber neuropathy, and therefore has potential for use in large scale clinical studies

    This Other Eden: Exploring a Sense of Place in Twentieth-Century Reconstructions of Australian Childhoods

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    This thesis explores the sense of place formed during childhood, as remembered by adult Australians who reconstruct their youth through various forms of life writing. While Australian writers do utilize traditional tropes of Western autobiography, such as the mythology of Eden and the Wordsworthian image of the child communing with Nature, these themes are frequently transformed to meet a uniquely Australian context. Isolation and distance from Europe, and the apparent indifference of our landscape towards white settlement, have received much critical attention in Australian studies generally and, indeed, broadly influence the formation of children’s sense of place across the continent. However, writers are also concerned with the role of place on a more local level. Through a comparison of writing from Western Australia, Queensland and Victoria, this thesis explores regional landscape preoccupations that create an awareness of local identity, variously contributing to or frustrating the child’s sense of belonging. Western Australian writing is dominated by images of isolation, the fragility of white settlement in a dry land lacking fresh water, and a pervasive beach culture. A strong sense of the littoral pervades writing from this region. Queensland’s frontier mythology is of a different flavour: warm and tropical, nature here is exuberant, constantly threatening to overwhelm culture, already perceived as transient due to the flimsy aspect of the “Queenslander” house. Writing from Victoria, to some extent, tends to more closely follow English models, juxtaposing country and city environments, although there is a distinctly local flavour to many representations of urban Melbourne and its flat, grid-like organization. As Australian society becomes more concentrated on the coastal fringe, the beach is an increasingly significant environment. Though more prominent in writing from some regions than others, coastal imagery broadly reflects the modern Australian’s sense of inhabiting a liminal zone with negotiable boundaries

    Validation of methods for converting the original Disease Activity Score (DAS) to the DAS28

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    © The Author(s) 2018.The Disease Activity Score (DAS) is integral in tailoring the clinical management of rheumatoid arthritis (RA) patients and is an important measure in clinical research. Different versions have been developed over the years to improve reliability and ease of use. Combining the original DAS and the newer DAS28 data in both contemporary and historical studies is important for both primary and secondary data analyses. As such, a methodologically robust means of converting the old DAS to the new DAS28 measure would be invaluable. Using data from The Early RA Study (ERAS), a sub-sample of patients with both DAS and DAS28 data were used to develop new regression imputation formulas using the total DAS score (univariate), and using the separate components of the DAS score (multivariate). DAS were transformed to DAS28 using an existing formula quoted in the literature, and the newly developed formulas. Bland and Altman plots were used to compare the transformed DAS with the recorded DAS28 to ascertain levels of agreement. The current transformation formula tended to overestimate the true DAS28 score, particularly at the higher end of the scale. A formula which uses all separate components of the DAS was found to estimate the scores with a higher level of precision. A new formula is proposed that can be used by other early RA cohorts to convert the original DAS to DAS28.Peer reviewedFinal Published versio

    Knowledge and Informed Decision-Making about Population-Based Colorectal Cancer Screening Participation in Groups with Low and Adequate Health Literacy

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    Objective. To analyze and compare decision-relevant knowledge, decisional conflict, and informed decision-making about colorectal cancer (CRC) screening participation between potential screening participants with low and adequate health literacy (HL), defined as the skills to access, understand, and apply information to make informed decisions about health. Methods. Survey including 71 individuals with low HL and 70 with adequate HL, all eligible for the Dutch organized CRC screening program. Knowledge, attitude, intention to participate, and decisional conflict were assessed after reading the standard information materials. HL was assessed using the Short Assessment of Health Literacy in Dutch. Informed decision-making was analyzed by the multidimensional measure of informed choice. Results. 64% of the study population had adequate knowledge of CRC and CRC screening (low HL 43/71 (61%), adequate HL 47/70 (67%), p>0.05). 57% were informed decision-makers (low HL 34/71 (55%), adequate HL 39/70 (58%), p>0.05). Intention to participate was 89% (low HL 63/71 (89%), adequate HL 63/70 (90%)). Respondents with low HL experienced significantly more decisional conflict (25.8 versus 16.1; p=0.00). Conclusion. Informed decision-making about CRC screening participation was suboptimal among both individuals with low HL and individuals with adequate HL. Further research is required to develop and implement effective strategies to convey decision-relevant knowledge about CRC screening to all screening invitees

    Identification of mixed-symmetry states in an odd-mass nearly-spherical nucleus

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    The low-spin structure of 93Nb has been studied using the (n,n' gamma) reaction at neutron energies ranging from 1.5 to 3.0 MeV and the 94Zr(p,2n gamma)93Nb reaction at bombarding energies from 11.5 to 19 MeV. States at 1779.7 and 1840.6 keV, respectively, are proposed as mixed-symmetry states associated with the coupling of a proton hole in the p_1/2 orbit to the 2+_1,ms state in 94Mo. These assignments are derived from the observed M1 and E2 transition strengths to the symmetric one-phonon states, energy systematics, spins and parities, and comparison with shell model calculations.Comment: 5 pages, 3 figure

    Lifetime determination of excited states in Cd-106

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    Two separate experiments using the Differential Decay Curve Method have been performed to extract mean lifetimes of excited states in 106 Cd. The inedium-spin states of interest were populated by the Mo-98(C-12, 4n) Cd-106 reaction performed at the Wright Nuclear Structure Lab., Yale University. From this experiment, two isomeric state mean lifetimes have been deduced. The low-lying states were populated by the Mo-96(C-13, 3n)Cd-106 reaction performed at the Institut fur Kernphysik, Universitat zu Koln. The mean lifetime of the I-pi = 2(1)(+) state was deduced, tentatively, as 16.4(9) ps. This value differs from the previously accepted literature value from Coulomb excitation of 10.43(9) ps

    Search for the electric dipole excitations to the 3s1/2⊗[21+⊗31−]3s_{1/2} \otimes [2^{+}_{1} \otimes 3^{-}_{1}] multiplet in 117^{117}Sn

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    The odd-mass 117^{117}Sn nucleus was investigated in nuclear resonance fluorescence experiments up to an endpoint energy of the incident photon spectrum of 4.1 MeV at the bremsstrahlung facility of the Stuttgart University. More than 50 mainly hitherto unknown levels were found. From the measurement of the scattering cross sections model independent absolute electric dipole excitation strengths were extracted. The measured angular distributions suggested the spins of 11 excited levels. Quasi-particle phonon model calculations including a complete configuration space were performed for the first time for a heavy odd-mass spherical nucleus. These calculations give a clear insight in the fragmentation and distribution of the E1E1, M1M1, and E2E2 excitation strength in the low energy region. It is proven that the 1−1^{-} component of the two-phonon [21+⊗31−][2^{+}_{1} \otimes 3^{-}_{1}] quintuplet built on top of the 1/2+1/2^{+} ground state is strongly fragmented. The theoretical calculations are consistent with the experimental data.Comment: 10 pages, 5 figure
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