Volatile and trace elements in basaltic glasses from Samoa : implications for water distribution in the mantle

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 241 (2006): 932-951, doi:10.1016/j.epsl.2005.10.028.We report volatile (H2O, CO2, F, S, Cl) and trace element data for submarine alkalic basalt glasses from the three youngest Samoan volcanoes, Ta’u, Malumalu and Vailulu’u. Most samples are visibly sulfide saturated, so have likely lost some S during fractionation. Cl/K ratios (0.04 – 0.15) extend to higher values than pristine MORBs, but are suspected to be partly due to source differences since Cl/K roughly varies as a function of 87Sr/86Sr. There are no resolvable differences in the relative enrichment of F among sources, and compatibility of F during mantle melting is established to be nearly identical to Nd. Shallow degassing has affected CO2 in all samples, and H2O only in the most shallowly erupted samples from Vailulu’u. Absolute water contents are high for Samoa (0.63 – 1.50 wt%), but relative enrichment of water compared to equally incompatible trace elements (Ce, La) is low and falls entirely below normal MORB values. H2O/Ce (58 – 157) and H2O/La (120 – 350) correlate inversely with 87Sr/86Sr compositions (0.7045 – 0.7089). This leads us to believe that, because of very fast diffusion of hydrogen in mantle minerals, recycled lithospheric material with high initial water and trace element content will lose water to the drier ambient mantle during storage within the inner Earth. The net result is the counter-intuitive appearance of greater dehydration with greater mantle enrichment. We expect that subducted slabs will experience a two-stage dehydration history, first within subduction zones and then in the ambient mantle during long-term convective mixing

Idiopathic toe walking and sensory processing dysfunction

<p>Abstract</p> <p>Background</p> <p>It is generally understood that toe walking involves the absence or limitation of heel strike in the contact phase of the gait cycle. Toe walking has been identified as a symptom of disease processes, trauma and/or neurogenic influences. When there is no obvious cause of the gait pattern, a diagnosis of idiopathic toe walking (ITW) is made. Although there has been limited research into the pathophysiology of ITW, there has been an increasing number of contemporary texts and practitioner debates proposing that this gait pattern is linked to a sensory processing dysfunction (SPD). The purpose of this paper is to examine the literature and provide a summary of what is known about the relationship between toe walking and SPD.</p> <p>Method</p> <p>Forty-nine articles were reviewed, predominantly sourced from peer reviewed journals. Five contemporary texts were also reviewed. The literature styles consisted of author opinion pieces, letters to the editor, clinical trials, case studies, classification studies, poster/conference abstracts and narrative literature reviews. Literature was assessed and graded according to level of evidence.</p> <p>Results</p> <p>Only one small prospective, descriptive study without control has been conducted in relation to idiopathic toe walking and sensory processing. A cross-sectional study into the prevalence of idiopathic toe walking proposed sensory processing as being a reason for the difference. A proposed link between ITW and sensory processing was found within four contemporary texts and one conference abstract.</p> <p>Conclusion</p> <p>Based on the limited conclusive evidence available, the relationship between ITW and sensory processing has not been confirmed. Given the limited number and types of studies together with the growing body of anecdotal evidence it is proposed that further investigation of this relationship would be advantageous.</p

Empowerment of Whom and for What? Financial Literacy Education and the New Regulation of Consumer Financial Services

Financial regulators in many states recently have obtained statuory mandates to enhance consumer financial literacy. This paper investicages the development of policy pursuant to such mandates in the UK and Canada to identify how national regulators in both countries represent financial market place. It finds that regulators in both countries represent financial education as empowerment and responsible consumer behaviour. The paper rekates the tension between empowerment and responsibilization aspects of literacy enhancement to policy goals of expectations of protection. It raises questions about regulators' use of consumer education to responsiblize consumption of financial products and calls for further research on the international growth of financial literacy education as a regulatory project

Melanoma cells undergo aggressive coalescence in a 3D Matrigel model that is repressed by anti-CD44

<div><p>Using unique computer-assisted 3D reconstruction software, it was previously demonstrated that tumorigenic cell lines derived from breast tumors, when seeded in a 3D Matrigel model, grew as clonal aggregates which, after approximately 100 hours, underwent coalescence mediated by specialized cells, eventually forming a highly structured large spheroid. Non-tumorigenic cells did not undergo coalescence. Because histological sections of melanomas forming in patients suggest that melanoma cells migrate and coalesce to form tumors, we tested whether they also underwent coalescence in a 3D Matrigel model. Melanoma cells exiting fragments of three independent melanomas or from secondary cultures derived from them, and cells from the melanoma line HTB-66, all underwent coalescence mediated by specialized cells in the 3D model. Normal melanocytes did not. However, coalescence of melanoma cells differed from that of breast-derived tumorigenic cell lines in that they 1) coalesced immediately, 2) underwent coalescence as individual cells as well as aggregates, 3) underwent coalescence far faster and 4) ultimately formed long, flat, fenestrated aggregates that were extremely dynamic. A screen of 51 purified monoclonal antibodies (mAbs) targeting cell surface-associated molecules revealed that two mAbs, anti-beta 1 integrin/(CD29) and anti-CD44, blocked melanoma cell coalescence. They also blocked coalescence of tumorigenic cells derived from a breast tumor. These results add weight to the commonality of coalescence as a characteristic of tumorigenic cells, as well as the usefulness of the 3D Matrigel model and software for both investigating the mechanisms regulating tumorigenesis and screening for potential anti-tumorigenesis mAbs.</p></div

Single cell facilitation of coalescence between two aggregates.

<p>The preparation was that of a secondary culture of melanoma cells derived from a melanoma biopsy. The single facilitator cell (magenta), attached to the small aggregate (blue), extended a tapering projection ending at the large aggregate (yellow). The large aggregate extended a green projection at 171 hours which in the direction of the cell, then attached to it. The projection of the magenta facilitator cell attached to another cell on the surface of the large yellow aggregate and contracted as a multicellular bridge formed (not shown), resulting in coalescence of the two aggregates. The small blue aggregate was incorporated into the large yellow aggregate by 173 hours, and was then color-coded yellow.</p

4D reconstructions are generated with a customized cabinet and J3D-DIAS4.2 software.

<p>A. The 3D platform included an upright light microscope supporting the 3D Matrigel preparation seeded with cells, a computer-synchronized mechanical stage, camera and light source for optical sectioning, and DIC optics. This system is housed in a 5% CO₂ incubator and maintained at 37°C. B. One hundred and fifty optical sections were collected in a 30 second period, as cartooned in this panel, and this sectioning process repeated every 10 minutes. Optical sections are drawn in grey. Blue boxes denote different depths. C. DIC optical sections obtained at four depths during one series of sectioning. D. Computer-assisted autotracing of the optical sections in C. E. 3D reconstruction by J3D-DIAS4.2 of an aggregate formed by coalescence, viewed from four angles.</p

The peptide A6 had no effect on the coalescence of HTB-66 cells in the 3D Matrigel model.

<p>A. DIC images of the absence of an effect on coalescence in the 3D Matrigel model in the wells of multiwell tissue culture dishes, by peptide concentrations ranging from 0 to 1 mg per ml after four days. B. 3D reconstructions of coalescence in the presence of 1 mg per ml between 42 and 106 hours of incubation in the 3D Matrigel model reveals continued coalescence. Curved white arrows in 42 hour panel point to aggregates that are partially obscured by another aggregate. Straight white arrows at 74 hours indicate the direction of travel of cells or aggregates that moved out of the field of view.</p

Coalescence of cells of the established melanoma cell line HTB-66 begins immediately after Matrigel coalescence and is rapid.

<p>Only the cells that coalesced into large aggregates in the 43 hour period of reconstruction are numbered.</p

Treatment with H4C4 also blocked coalescence of melanoma cells exiting fresh melanoma tissue in the 3D Matrigel model.

<p>A. Only one potential coalescence event was observed in the treated preparation (white arrow, 48 hr), but the bridge that formed did not fully did not pull the smaller into the larger aggregate and the cells separated at 52 hr (white arrow, 52 hr). B. Coalescence in the absence of mAb. Coalesced cells are color-coded blue in panel B.</p

Cells subcultured from melanoma and seeded in Matrigel undergo cell-aggregate and aggregate-aggregate coalescence.

<p>The three examples in panels A, B and C were reconstructed at different times and different locations of a single preparation. A. Example of a cell (blue) translocating to a small aggregate (red) and coalescing with it, in a four hour period. B. Example of three individual cells (green, yellow, blue) coalescing with an aggregate (red), between 45.5 and 49 hours. C. Examples of cell-aggregate and aggregate-aggregate coalescence between 140 and 279 hours of reconstruction. In these panels, the original cells and small aggregates that undergo coalescence are multicolored and numbered so that they can be monitored through coalescence. Note that cells and aggregates 1, 2, 3, 7, 8, 9, 10, 11 and 12 form the aggregate labeled 1/2/3/7/8/9/10/11/12 and cells 4, 5 and 6 form 4/5/6 aggregate.</p