Ileocolic intussusception due to Burkitt lymphoma: a case report

Burkitt lymphoma has many forms of clinical presentations and, in children, it is usually discovered due to the presence of an abdominal mass. This rapidly growing tumor is highly malignant, aggressive, and may cause either indirect symptoms, due to pressure phenomena or direct involvement of the bowel lumen, leading to either intestinal obstruction or intussusception. We describe the case of a 4-year-old girl who exhibited an unusual presentation of ileocolic intussusception on a Burkitt lymphoma lesion of the ileum.

Synthesis and micellization of polydimethylsiloxane– carboxy-terminated poly(ethylene oxide) graft copolymer in aqueous and organic media and its application for the synthesis of core-shell magnetite particles

An amphiphilic graft copolymer having an average of 7-8 carboxyesterterminated poly(ethylene oxide) grafted sequences on each polydimethylsiloxane main chain was obtained by a multistep procedure. Through fluorescence, surface tension and laser diffractometry methods the graft copolymer was proved to undergo micellization in aqueous media. In water, the critical micellization concentrations (CMC) are dependent on pH. Two CMC values were established for pH = 4, i.e. CMC1 = 1.01 g/L and CMC2 = 1.73 g/L corresponding to the transition from single chain to multiple chain micelles and to intermicellar aggregation, respectively. Between CMC1 and CMC2, the dimensions of micelles increased from 18 nm to 46 nm. The graft copolymer was proved to efficiently act as surfactant in the preparation of magnetite particles with a hydrophobic siloxane shell.

Surface Properties of Cellulose Acetate

Cellulose acetates with different substitution degrees were investigated as to their surface tension properties and morphology. Atomic force microscopy (AFM) studies on membranes, obtained from solution in acetone/water nonsolvent mixtures, evidenced pores and nodules of different size and intensity, depending on the substitution degrees of cellulose acetate and on the water contents in nonsolvent mixtures. Modification of hydrophilicity, put into evidence by the apolar components and by the electron acceptor and electron donor parameters of the polar components, was correlated with the pores volumes — influenced both by their diameter and depths, and by surface roughness as illustrated by AFM images. Surface wettability trends were also studied by means of the free energy of hydration between compounds and water.

Glycidoxypropylsilane-functionalized Magnetite as Precursor for Polymer-covered Core-shell Magnetic Particles

Surface-functionalized core-shell magnetic particles were obtained by reacting the hydroxyl groups on the surface of pre-prepared magnetite particles with 3-glycidoxypropyltrimethoxysilane. Fourier transform infrared spectra indicated that epoxy silane molecules were chemically bound onto the surface of magnetite particles through Fe—O—Si linkages. As proved by atomic force microscopy and environmental scanning microscopy combined with energy dispersive X-ray spectroscopy, particles with average core diameter and shell width of about 700 and 70 nm, respectively, were obtained. The covered magnetite particles showed a lower saturation magnetization (46 emu g 1) as compared to the uncoated magnetite (64 emu g 1).

Structural and dielectric properties of some epiclon-based polyimide films

Surface and electrical properties of two flexible and cross-linked epiclon based polyimide films were investigated. Surface tension measurements indicate an increased hydrophobicity due to both isothermal treatment - which induces imidization and cross-linking - and to the chemical structure, characterized by the different number of ether linkages in the polyimide backbone. Morphology of film surfaces, modified by plasma treatment, shows high roughness and, implicitly, improved adhesion, as required in electronics. The studied polyimides exhibit low dielectric constants and dielectric losses, comparatively to conventional aromatic polyimides. The electrical conductance and resistivity characteristics of these polymers recommend them as good insulators for dielectric layers in microelectronic applications.

Solvent Interactions and Protein Dynamics in Spin-labeled T4 Lysozyme

Aspects of T4 lysozyme dynamics and solvent interaction are investigated using atomically detailed Molecular Dynamics (MD) simulations. Two spin-labeled mutants of T4 lysozyme are analyzed (T4L-N40C and T4L-K48C), which have been found from electronic paramagnetic resonance (EPR) experiments to exhibit different mobilities at the site of spin probe attachment (N- and C-terminus of helix B, respectively). Similarities and differences in solvent distribution and diffusion around the spin label, as well as around exposed and buried residues within the protein, are discussed. The purpose is to capture possible strong interactions between the spin label (ring) and solvent molecules, which may affect EPR lineshapes. The effect of backbone motions on the water density profiles is also investigated. The focus is on the domain closure associated with the T4 lysozyme hinge-bending motion, which is analyzed by Essential Dynamics (ED). The N-terminus of helix B is found to be a "hinge" residue, which explains the high degree of flexibility and motional freedom at this site.