151 research outputs found
Development of methods for predicting large crack growth in elastic-plastic work-hardening materials in fully plastic conditions
The objects of the first, exploratory, stage of the project were listed as: (1) to make a detailed and critical review of the Boundary Element method as already published and with regard to elastic-plastic fracture mechanics, to assess its potential for handling present concepts in two-dimensional and three-dimensional cases. To this was subsequently added the Finite Volume method and certain aspects of the Finite Element method for comparative purposes; (2) to assess the further steps needed to apply the methods so far developed to the general field, covering a practical range of geometries, work hardening materials, and composites: to consider their application under higher temperature conditions; (3) to re-assess the present stage of development of the energy dissipation rate, crack tip opening angle and J-integral models in relation to the possibilities of producing a unified technology with the previous two items; and (4) to report on the feasibility and promise of this combined approach and, if appropriate, make recommendations for the second stage aimed at developing a generalized crack growth technology for its application to real-life problems
Metallurgy of open-bath plasma processes
Abstract -Thermodynamic simulation of the carbothermic chemical reactions likely to occur in the open bath of a d.c. transferred plasma-arc furnace using a standard slag comprising CaO, MgO, A1203, and SiO, as a basis, and with FeO, Crz03, MnO, and ZnO added at various carbon levels, has shown that the high temperatures expected in the arc attachment zone (AAZ) can cause unacceptable products to be produced at the expense of the desired ones and result in higher consumption of energy. The thermal inertia of the AAZ can be used in efforts to assess the level of control needed over the feed rate, distribution of the feed, and power input of a particular process in order to limit high temperature excursions, which cause so-called 'side reactions', e.g. the reduction of MgO to Mg vapour
Corneal involvement in Graves' orbitopathy : an in vivo confocal study
PURPOSE: To study the clinical involvement of the ocular surface and the in vivo
morphology of corneal cells and nerves, in patients affected by active and
inactive Graves' orbitopathy (GO).
METHODS: The study included 26 consecutive GO patients and 20 age- and
sex-matched healthy control subjects. GO was diagnosed on the basis of the
criteria of the European Group on Graves' Orbitopathy, and disease activity was
evaluated by the Clinical Activity Score (CAS). Each participant underwent a full
eye examination, including an evaluation of symptoms (Ocular Surface Disease
Index score), tear break-up time, fluorescein and lissamine green staining,
corneal apex sensitivity, and Schirmer's test. The corneal apex was examined by
means of confocal microscopy to investigate the number and morphology of
epithelial and stromal corneal cells and subbasal nerves.
RESULTS: Eleven (43%) of the 26 patients had active GO. One-way ANOVA with the
least-significant difference (LSD) post hoc test revealed statistically
significant differences between patients and controls in all the evaluated
parameters, except corneal sensitivity and nerve reflectivity. Among the GO
patients, the only significant difference observed in active compared with
inactive disease was in the number of hyperreflective (activated) keratocytes
(P<0.001, LSD). Corneal sensitivity correlated inversely with proptosis (P<0.001,
Spearman's test).
CONCLUSIONS: GO patients show clinical and confocal corneal alterations and signs
and symptoms partially related to dry eye disease. The ocular surface
inflammation in GO seems to be due to both the dry eye and the autoimmune
orbitopathy
Antibodies to neurofascin, contactin-1, and contactin-associated protein 1 in CIDP: Clinical relevance of IgG isotype.
Objective: To assess the prevalence and isotypes of anti-nodal/paranodal antibodies to nodal/paranodal proteins in a large chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) cohort, compare clinical features in seronegative vs seropositive patients, and gather evidence of their isotype-specific pathogenic role.
Methods: Antibodies to neurofascin-155 (Nfasc155), neurofascin-140/186 (Nfasc140/186), contactin-1 (CNTN1), and contactin-associated protein 1 (Caspr1) were detected with ELISA and/or cell-based assay. Antibody pathogenicity was tested by immunohistochemistry on skin biopsy, intraneural injection, and cell aggregation assay.
Results: Of 342 patients with CIDP, 19 (5.5%) had antibodies against Nfasc155 (n = 9), Nfasc140/186 and Nfasc155 (n = 1), CNTN1 (n = 3), and Caspr1 (n = 6). Antibodies were absent from healthy and disease controls, including neuropathies of different causes, and were mostly detected in patients with European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) definite CIDP (n = 18). Predominant antibody isotypes were immunoglobulin G (IgG)4 (n = 13), IgG3 (n = 2), IgG1 (n = 2), or undetectable (n = 2). IgG4 antibody-associated phenotypes included onset before 30 years, severe neuropathy, subacute onset, tremor, sensory ataxia, and poor response to intravenous immunoglobulin (IVIG). Immunosuppressive treatments, including rituximab, cyclophosphamide, and methotrexate, proved effective if started early in IVIG-resistant IgG4-seropositive cases. Five patients with an IgG1, IgG3, or undetectable isotype showed clinical features indistinguishable from seronegative patients, including good response to IVIG. IgG4 autoantibodies were associated with morphological changes at paranodes in patients' skin biopsies. We also provided preliminary evidence from a single patient about the pathogenicity of anti-Caspr1 IgG4, showing their ability to penetrate paranodal regions and disrupt the integrity of the Nfasc155/CNTN1/Caspr1 complex.
Conclusions: Our findings confirm previous data on the tight clinico-serological correlation between antibodies to nodal/paranodal proteins and CIDP. Despite the low prevalence, testing for their presence and isotype could ultimately be part of the diagnostic workup in suspected inflammatory demyelinating neuropathy to improve diagnostic accuracy and guide treatment.
Classification of evidence: This study provides Class III evidence that antibodies to nodal/paranodal proteins identify patients with CIDP (sensitivity 6%, specificity 100%)
Diversities, affinities and diasporas: a southern lens and methodology for understanding multilingualisms
We frame multilingualisms through a growing interest in a linguistics and sociology of the ‘south’ and acknowledge earlier contributions of linguists in Africa, the Américas and Asia who have engaged with human mobility, linguistic contact and consequential ecologies that alter over time and space. Recently, conversations of multilingualism have drifted in two directions. Southern conversations have become intertwined with ‘decolonial theory’, and with ‘southern’ theory, thinking and epistemologies. In these, ‘southern’ is regarded as a metaphor for marginality, coloniality and entanglements of the geopolitical north and south. Northern debates that receive traction appear to focus on recent ‘re-awakenings’ in Europe and North America that mis-remember southern experiences of linguistic diversity. We provide a contextual backdrop for articles in this issue that illustrate intelligences of multilingualisms and the linguistic citizenship of southern people. In these, southern multilingualisms are revealed as phenomena, rather than as a phenomenon defined usually in English. The intention is to suggest a third direction of mutual advantage in rethinking the social imaginary in relation to communality, entanglements and interconnectivities of both South and North
Ecological drivers of plant diversity patterns in remnants coastal sand dune ecosystems along the northern Adriatic coastline
Coastal sand dunes represent one of the most fragile ecosystems in the Mediterranean basin. These habitats naturally suffer the action of several limiting factors such as sand burial, marine aerosol and low soil fertility; on the other hand, they often host species of high conservation value. Over the last decades, they have also experienced a high level of biological invasion. In this study, we sampled psammophilous vegetation in two sites in the northern Adriatic coast belonging to the Natura 2000 network to describe diversity patterns and to identify the main ecological drivers of species diversity. Plant species richness and their abundance were assessed in each plot. Differences in species composition for native and alien species were compared via PERMANOVA analysis. Species complementarity was explored by partitioning beta diversity in its spatial components (richness and replacement). A Generalized Linear Model was also computed to assess the main environmental factors that may promote invasiveness in these ecosystems. For the investigated area, our results highlight the strong differentiation in community composition both in alien and native species: in particular alien species showed on average a lower complementarity among habitats compared to native species. Specifically, communities seem to be more diversified when larger spatial scales were considered. Beta diversity in both groups appears to be more dominated by the richness component with respect to the replacement component. Furthermore, in these habitats, the occurrence of alien species was shown to be related to geomorphological predictors more than climatic variables
Tracing Beach Sand Provenance and Transport using Foraminifera: Preliminary Examples from Northwest Europe and Southeast Australia
Foraminifera are marine Sarcodine Protozoa that possess tests (shells) that are preservable in the fossil record. These tests may either be constructed using organically cemented detritus (agglutinating or arenaceous forms), or secreted using calcium carbonate (calcareous forms). Their ecology embraces planktonic and benthonic modes, although planktonic forms generally inhabit the open ocean and seldom live in coastal waters in any abundance, while benthonic foraminifera exist on substrates from abyssal plains to high intertidal areas. There are many species of foraminifera that are niche-specific, making them ideal for palaeoenvironmental analysis (Boersma, 1978; Brasier, 1980; Murray, 1991; Culver, 1993)
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