The Chattanooga Procedure: A New Technique Used for Anterior Multi-level Cervical Fusions

STUDY DESIGN: A preliminary assessment of anterior cervical fusion performed with interbody cage and DOC plate. OBJECTIVES: To describe and evaluate the efficacy and safety of the Chattanooga Procedure , a modified technique in achieving anterior cervical fusion. SUMMARY OF BACKGROUND DATA: Anterior cervical fusion with interbody bone graft and anterior plating is connnonly performed. Unfortunately, the plate has been reported to shield the graft from loading thus reducing fusion rates. The use of interbody fusion cages has been effective in the lumbar spine and has gained acceptance in the cervical spine. METHODS:. Twenty-five patients received The Chattanooga Procedure between 7/24/98 and 4/8/99. All patients had anterior discectomies and carpectomies, placement of a Harms cage packed with carpectomy bone, and application ofDePuy-Acromed DOC. Fusion was defined by radiographic evidence of trabecular bone bridging across the Harms cage. CT scans were performed on twelve randomly chosen patients to verify fusion. No external bracing was used except a soft collar as needed. Pre- and post-operative pain and functional capacity data were collected and statistically analyzed using paired t-tests. RESULTS: There were no cases of pseudoarthrosis, major neurological, vascular, or wound complications. Only one case of unresolved dysphasia was noted. The average operative time (11 0 minutes) was comparable to standard instrumented multi-level anterior cervical fusion surgeries. The average estimated blood loss was 113 ml (range, 50-750 ml). Both visual analog pain scale and Oswestry functional capacity data were significantly improved post-operatively (p\u3c 0.01). DISCUSSION: Advantages of the Chattanooga Procedure include immediate stability, support, elimination of donor site pain to iliac crest bone autograft, and a decrease in pseudoarthrosis by dividing the fusion surfaces by half. Concerns regarding this technique include an increased risk for dysphasia due to the DOC\u27s high profile. Pseudoarthrosis or instrumentation migration could also become problematic since the removal of the Harms cage could be difficult if necessary

Subduction-driven recycling of continental margin lithosphere

Whereas subduction recycling of oceanic lithosphere is one of the central themes of plate tectonics, the recycling of continental lithosphere appears to be far more complicated and less well understood(1). Delamination and convective downwelling are two widely recognized processes invoked to explain the removal of lithospheric mantle under or adjacent to orogenic belts(2-5). Here we relate oceanic plate subduction to removal of adjacent continental lithosphere in certain plate tectonic settings. We have developed teleseismic body wave images from dense broadband seismic experiments that show higher than expected volumes of anomalously fast mantle associated with the subducted Atlantic slab under northeastern South America and the Alboran slab beneath the Gibraltar arc region(6,7); the anomalies are under, and are aligned with, the continental margins at depths greater than 200 kilometres. Rayleigh wave analysis(8,9) finds that the lithospheric mantle under the continental margins is significantly thinner than expected, and that thin lithosphere extends from the orogens adjacent to the subduction zones inland to the edges of nearby cratonic cores. Taking these data together, here we describe a process that can lead to the loss of continental lithosphere adjacent to a subduction zone. Subducting oceanic plates can viscously entrain and remove the bottom of the continental thermal boundary layer lithosphere from adjacent continental margins. This drives surface tectonics and pre-conditions the margins for further deformation by creating topography along the lithosphere-asthenosphere boundary. This can lead to development of secondary downwellings under the continental interior, probably under both South America and the Gibraltar arc(8,10), and to delamination of the entire lithospheric mantle, as around the Gibraltar arc(11). This process reconciles numerous, sometimes mutually exclusive, geodynamic models proposed to explain the complex oceanic-continental tectonics of these subduction zones(12-17)This research was supported by US National Science Foundation grants EAR 0003572, 0607801 and 0808939 (A.L.), EAR 0808931 (E.D.H.), EAR 0809023 and 1054638 (M.S.M.), the Venezuelan National Fund for Science, Technology and Innovation grant G-2002000478 and PDVSA-INTEVEP-FUNVISIS cooperative agreement 2004-141 (M.S.), the Spanish Ministry of Science and Innovation grants CSD2006-00041, CGL2009-09727 and CGL2010-15146 (J.G. and R.C.), and by an A. v. Humboldt Foundation Research Prize (A.L.).Peer Reviewe

Experimental study and multiscale modelling of the high temperature deformation of tempered martensite under multiaxial loading

peer-reviewedThe microstructural deformation of ex-service 9Cr-1Mo steel, with a tempered martensitic microstructure, has been examined in this study, through the combined use of electron backscatter diffraction (EBSD) and multiscale modelling techniques. Both the experimental and predicted deformation of the material at a notch root on a range of scales from the specimen level down to the microstructural block level are compared. A tension loaded notch specimen of the material which was extracted from an ex-service power plant pipe was used for this analysis. The deformation at the specimen level was quantified by analysis of the load displacement curves and notch opening displacement, which showed excellent agreement with the predicted results from the experimentally calibrated elastic-plastic finite-element model of the specimen geometry. The microstructural deformation was experimentally measured through the use of EBSD carried out at the notch root before and after high temperature mechanical testing. The initial orientation of the microstructure as well as the displacement around the boundary of the area of interest in the macroscale model were applied to a representative volume element (RVE) and a slip based crystal plasticity modelling framework was implemented to model the in-elastic deformation of the material under high temperature loading

Astronomical Distance Determination in the Space Age: Secondary Distance Indicators

The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations. © 2018, The Author(s)

Intoxicação por monofluoroacetato em animais

O monofluoroacetato (MF) ou ácido monofluoroacético é utilizado na Austrália e Nova Zelândia no controle populacional de mamíferos nativos ou exóticos. O uso desse composto é proibido no Brasil, devido ao risco de intoxicação de seres humanos e de animais, uma vez que a substância permanece estável por décadas. No Brasil casos recentes de intoxicação criminosa ou acidental têm sido registrados. MF foi identificado em diversas plantas tóxicas, cuja ingestão determina "morte súbita"; de bovinos na África do Sul, Austrália e no Brasil. O modo de ação dessa substância baseia-se na formação do fluorocitrato, seu metabólito ativo, que bloqueia competitivamente a aconitase e o ciclo de Krebs, o que reduz produção de ATP. As espécies animais têm sido classificadas nas quatro Categorias em função do efeito provocado por MF: (I) no coração, (II) no sistema nervoso central (III) sobre o coração e sistema nervoso central ou (IV) com sintomatologia atípica. Neste trabalho, apresenta-se uma revisão crítica atualizada sobre essa substância. O diagnóstico da intoxicação por MF é realizado pelo histórico de ingestão do tóxico, pelos achados clínicos e confirmado por exame toxicológico. Uma forma peculiar de degeneração hidrópico-vacuolar das células epiteliais dos túbulos uriníferos contorcidos distais tem sido considerada como característica dessa intoxicação em algumas espécies. O tratamento da intoxicação por MF é um desafio, pois ainda não se conhece um agente capaz de reverte-la de maneira eficaz; o desfecho geralmente é fata

Piecewise delamination of Moroccan lithosphere from beneath the Atlas Mountains

The elevation of the intracontinental Atlas Mountains of Morocco and surrounding regions requires a mantle component of buoyancy, and there is consensus that this buoyancy results from an abnormally thin lithosphere. Lithospheric delamination under the Atlas Mountains and thermal erosion caused by upwelling mantle have each been suggested as thinning mechanisms. We use seismic tomography to image the upper mantle of Morocco. Our imaging resolves the location and shape of lithospheric cavities and of delaminated lithosphere ∼400 km beneath the Middle Atlas. We propose discontinuous delamination of an intrinsically unstable Atlas lithosphere, enabled by the presence of anomalously hot mantle, as a mechanism for producing the imaged structures. The Atlas lithosphere was made unstable by a combination of tectonic shortening and eclogite loading during Mesozoic rifting and Cenozoic magmatism. The presence of hot mantle sourced from regional upwellings in northern Africa or the Canary Islands enhanced the instability of this lithosphere. Flow around the retreating Alboran slab focused upwelling mantle under the Middle Atlas, which we infer to be the site of the most recent delamination. The Atlas Mountains of Morocco stand as an example of large-scale lithospheric loss in a mildly contractional orogen. Key Points We image lithospheric cavities beneath the Middle Atlas and central HighAtlas We image the delaminated lithosphere of the Middle Atlas at ∼400 km depth We propose piecewise delamination of Atlas lithosphere © 2014. American Geophysical Union. All Rights Reserved.This work is funded by the PICASSO project (NSF grant EAR-0808939). The deployment and data processing for Spanish stations was funded by Consolider-Ingenio 2010 project TOPO-IBERIA (CSD2006-00041) as well as ALERT-ES (CGL2010-19803-C03-02).Peer Reviewe

The labour of user co-creators: Emergent social network markets?

Co-creative relations among professional media producers and consumers indicate a profound shift in which our frameworks and categories of analysis (such as the traditional labour theory of value) that worked well in the context of an industrial media economy are perhaps less helpful than before. Can this phenomenon just be explained as the exploitative extraction of surplus value from the work of users, or is something else, potentially more profound and challenging, playing out here? Does consumer co-creation contribute to the precarious conditions of professional creative workers? This article draws from ethnographic research undertaken from 2000 to 2005 with Auran games (a game development company based in Brisbane, Australia) to engage with debates about the status of user co-creation as labour. The article argues that as a hybrid and emergent social network market these relationships introduce a form of creative destruction to labour relations in the context of the creative industries

Evidence for slab rollback in westernmost Mediterranean from improved upper mantle imaging

This work is funded by the PICASSO project (NSF grant EAR-0808939), The deployment and data processing for Spanish stations was funded by Consolider-Ingenio 2010 project TOPO-IBERIA (CSD2006-00041) as well as ALERT-ES (CGL2010-19803-C03-02).Peer Reviewe

Absence of Class II-Associated Invariant Chain Peptide on Leukemic Blasts of Patients Promotes Activation of Autologous Leukemia-Reactive CD4(+) T Cells

Immune escape in cancer poses a substantial obstacle to successful cancer immunotherapy. Multiple defects in HLA class I antigen presentation exist in cancer that may contribute to immune escape, but less is known about roles for HLA class II antigen presentation. On class II+ leukemic blasts, the presence of class II-associated invariant chain peptide (CLIP) is known to be correlated with poor survival in acute myeloid leukemia (AML). In this study, we evaluated the functional significance of CLIP expression on leukemic blasts of AML patients. CD4(+) T cells from patients were cocultured with autologous CLIP- and CLIP+ primary leukemic blasts and analyzed for several functional parameters by flow cytometry. Increased HLA-DR and IFN-gamma expression was observed for CD4(+) T cells stimulated with CLIP- leukemic blasts, in contrast to CLIP+ leukemic blasts, which indicated an activation and polarization of the CD4(+) T cells toward T-helper 1 cells. In addition, CLIP- leukemic blasts induced greater outgrowth of effector memory CD4(+) T cells (with HLA-DR-restricted T-cell receptor V beta repertoires) that were associated with better leukemia-specific reactivity than with CLIP+ leukemic blasts. Our findings offer a clinical rationale to downmodulate CLIP on leukemic blasts as a strategy to degrade immune escape and improve leukemia-specific T-cell immunity in AML patients. Cancer Res; 71(7); 2507-17. (C)2011 AAC