Pediatric T- and NK-cell lymphomas: new biologic insights and treatment strategies

T- and natural killer (NK)-cell lymphomas are challenging childhood neoplasms. These cancers have varying presentations, vast molecular heterogeneity, and several are quite unusual in the West, creating diagnostic challenges. Over 20 distinct T- and NK-cell neoplasms are recognized by the 2008 World Health Organization classification, demonstrating the diversity and potential complexity of these cases. In pediatric populations, selection of optimal therapy poses an additional quandary, as most of these malignancies have not been studied in large randomized clinical trials. Despite their rarity, exciting molecular discoveries are yielding insights into these clinicopathologic entities, improving the accuracy of our diagnoses of these cancers, and expanding our ability to effectively treat them, including the use of new targeted therapies. Here, we summarize this fascinating group of lymphomas, with particular attention to the three most common subtypes: T-lymphoblastic lymphoma, anaplastic large cell lymphoma, and peripheral T-cell lymphoma-not otherwise specified. We highlight recent findings regarding their molecular etiologies, new biologic markers, and cutting-edge therapeutic strategies applied to this intriguing class of neoplasms

Composite electrode of carbon nanotubes and vitreous carbon for electron field emission

In this work, the electron field emission behaviour of electrodes formed by carbon nanotubes (CNTs) grown onto monolithic vitreous carbon (VCarbon) substrates with microcavities is presented. Scanning electron microscopy was used to characterize the microstructure of the films. Tungsten probes, stainless steel sphere, and phosphor electrodes were employed in the electron field emission study. The CNT/VCarbon composite represents a route to inexpensive excellent large area electron emission cathodes with fields as low as 2.1 V mu m(-1). In preliminary lifetime tests for a period of about 24 h at an emission current of about 4 mA cm(-2), there is an onset degradation of the emission current of about 28%, which then stabilizes. Electron emission images of the composites show the cavity of the samples act as separate emission sites and predominantly control the emission process. The emission of CNTs/VCarbon was found to be stable for several hours.</p

Raman investigation on thin-film electrodes of a-C:Li

Amorphous carbon films, deposited via radio frequency magnetron sputtering, have been electrochemically intercalated with lithium to study their possible application as anodes for rechargeable Li microbatteries. Various concentrations of intercalated lithium have been obtained by using galvanostatic and potentiostatic methods. After preliminary examinations by optical microscopy and by optical absorption measurement, a comparative Raman spectroscopy characterization of the films has been performed with excitation wavelengths ranging from 676.4 to 457.9 nm, to follow resonance effects. A study is made on the Raman spectral shape and its excitation wavelength dependence for the film samples with different Li concentrations. A moderate graphitization process of a-C films after intercalation results from this analysis, The Raman spectral changes induced by Li insertion ion not reverse after further de-intercalation cycles, and this fact is discussed in connection to the observed electrochemical reversibility of the a-C:Li electrodes

Conductivity and Mechanical Properties of Composites Based on MWCNTs and Styrene-Butadiene-Styrene Block (TM) Copolymers

Composites based on multiwall carbon nanotubes (MWCNTs) and the block copolymer styrene-butadiene-styrene with two different contents of styrene have been investigated and their electrical conductivity and mechanical properties have been evaluated. The composites were prepared by a Solution casting procedure, using a dispersant agent for the MWCNTs. Conductivity values of 10(-4) and 1.6 S cm(-1) have been obtained for samples containing 1 and 12 wt % of MWCNTs, respectively. The percolation threshold achieved for these systems was -0.25 wt %. According to dynamic mechanical analysis, the MWCNTs interact with both phases of the copolymers, acting as a reinforcement filler, whereas the dispersant agent acts as a plasticizer. However, it was shown that the reinforcing effect of the MWCNTs overcomes the latter, resulting in an overall improvement of mechanical properties of the composites. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 3241-3248, 2009112632413248URP microscopes of the Electron Microscope Laboratory, LNLS, Campinas [FEG-SEM JSM 6330F, HRTEM-JEM-3010]URP microscopes of the Electron Microscope Laboratory, LNLS, Campinas [FEG-SEM JSM 6330F, HRTEM-JEM-3010