Preparation of cadmium selenide-polyolefin composites from functional phosphine oxides and ruthenium-based metathesis

Cadmium selenide nanoparticles, prepared by known methods, were stabilized with functional phosphine oxide 1, then used to support the polymerization of cyclic olefins radially outward from the surface by ruthenium-catalyzed ring-opening metathesis polymerization (ROMP). The conversion of compound 1 into the new metathesis catalyst 3 by carbene exchange and the subsequent polymerization of cyclic olefins were observed spectroscopically by (1)H NMR to afford for example CdSe-polycyclooctene composite 6. Transmission electron micrographs on thin films of these composites showed good nanoparticle dispersion. This is in stark contrast to the substantial nanoparticle aggregation observed when similar polymerizations were performed in the presence of conventional TOPO-covered nanoparticles. The methods reported here to prepare composite product 6 are applicable to other cyclic olefins, and suggest that this chemistry will be useful for incorporating CdSe nanoparticles into a wide variety of polymer matrices.     

Nuclear-Electron Overhauser Effect in MC800 Liquid Asphalt Solutions

Experimental results on the extrapolated ultimate enhancement factors of o-, m-, and p-xylene protons at 1.53 mT are obtained for MC800 asphalt solutions. The ultimate enhancement factors are found such as ?26.9, ?25.7, and ?11.7 for o-, m-, and p-xylene, respectively. These results show that the solvent proton Overhauser effect cannot reach the extrapolated enhancement of ?330 in the extreme narrowing case because of occurrence of small scalar interactions in addition to the dipole–dipole interactions between solvent protons and asphalt electrons. The ortho, meta, and para positions of the –CH₃ group change the nature of the interactions. The nuclear magnetic resonance (NMR) signal enhancements exhibit a sensitive behavior depending on the chemical environment differing from isomer to isomer. The solvation or association of asphalt in xylene isomers at room temperature is revealed. Quantum chemical calculations for the xylene isomers with the electronic and optical properties; absorption wavelengths, excitation energy, atomic charges, dipole moment and frontier molecular orbital energies, molecular electrostatic potential; are carried out using the density functional theory (DFT) method (B3LYP) with the 6-311G(d,p) basis set by the standard Gaussian 09 software package program. The relative importance of scalar and translational dipolar interaction parameters determined in dynamic nuclear polarization experiments is explained by the electronic structure of HOMO–LUMO of the xylene isomers.     

MRI findings of primary small-cell carcinoma of kidney

We report the MRI findings of primary small-cell carcinoma of the kidney (PSCCK) in a 59-year-old female. This tumor appeared as a 16-cm mass that arose from the right kidney. This lesion had diminished signal on T1-weighted images and heterogeneous mixed signal on T2-weighted images. The tumor primarily involved the renal medulla with persistent thin renal cortex. Despite the tumors' large size, no substantial central necrosis was present. The predominant medullary location and the lack of central necrosis in this large tumor were features unusual for renal cell carcinoma and should raise the suspicion of another malignancy, the differential diagnosis of which should contain extrapulmonary small-cell carcinoma of the kidney.     

An unusual case of acute disseminated encephalomyelitis confined to brainstem

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated demyelinating disorder usually encountered in children or adolescents and characterized by multifocal neurological deficits of rapid onset. Typical target areas of demyelination include the corona radiata, centrum semiovale, periventricular white matter, cerebellar peduncles and brainstem. Involvement of deep gray matter nuclei is also frequent. We report a 6-year-old boy with ADEM who had only brainstem involvement. Serial magnetic resonance images representing the stage of disease and response to steroid treatment are presented.     

Hazardous metal geochemistry of sedimentary phosphate rock used for fertilizer (Maz?dag, SE Anatolia, Turkey)

Composition of phosphate rocks mostly depend on their type and origin. Sedimentary rocks contain high concentration of heavy metals. Phosphate rocks are mainly used for the manufacturing of phosphate fertilizers. The contents of heavy metals Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn, as well as rare earth elements Ce, La, and Th were determined in sedimentary phosphate rock used for production of fertilizer in Turkey. The Kasrik-Semikan, Mazidag (Mardin, SE Anatolia, Turkey) high-grade phosphate rock used in this study is situated near the border with Syria and was deposited during the Turonian and Senonian (Cretaceous) ages. Total phosphorus (P) concentration in the rock is 18.5% on the average. Microwave acid digestion (MW-AD) followed by ?nductively Coupled Plasma-Optical Emission Spectrophotometry (ICP-OES) was carried out for the determination of all the elements of interest in phosphate rock. The results revealed that hazardous metal content of the phosphate rock was lower in Mazidag phosphate than that in samples imported from other countries and were within the safety limits.     

Chemical profile by LC–MS/MS,GC/MS and antioxidant activities of the essential oils and crude extracts of two Euphorbia species

In this study, it was aimed to investigate the chemical composition and antioxidant activities of two Euphorbia species. The major component of the fatty acid compositions obtained from the petroleum ether extracts was identified as palmitic acid for Euphorbia gaillardotii and Euphorbia macroclada. The main constituents of the essential oils were identified as arachidic acid for E. gaillardotii and tetratetracontane for E. macroclada. Among the 27 studied compounds, hesperidin, rutin, hyperoside and quinic, malic, gallic and tannic acids were found to be the most abundant compounds in the two Euphorbia species. The methanol extracts of E. gaillardotii and E. macroclada showed strong antioxidant activity in all tested methods. Particularly, IC₅₀ values of E. macroclada methanol extract that was the richest in terms of total phenolic-flavonoid contents were found to be lower than α-tocopherol and butylated hydroxytoluene in β-carotene bleaching, 2,2-diphenyl-1-picrylhydrazyl free and ABTS cation radical scavenging methods.     

Duplex strand formation using alternating copolymers

The regular arrangement of complementary diaminopyridine-thymine (DAP-THY) on alternating copolymers permits cooperative binding events and the effective formation of well-controlled micrometre-scale aggregates.     

Polyglycidol Based Amphiphilic Double‐Comb Copolymers and Their Self‐Association in Aqueous Solution

Herein, we report synthesis and self‐association properties of amphiphilic double‐comb polymers with polyglycidol backbones. First, a bifunctional polyglycidol precursor is synthesized via monomer activated anionic polymerization. Next, two efficient and orthogonal polymer analogous reactions are carried out for grafting hydrophilic oligoethylene glycol side chains and hydrophobic linear aliphatic side‐chains. The polymers are analyzed by means of NMR, GPC, and DSC. From the DSC analysis of the bulk samples it is evident that aliphatic side chains segregate from the polar backbone and thus crystallize. Furthermore, in aqueous media the double‐comb polymers spontaneously self‐assemble to form a multilayer structure. The present results pave a way to tailor and design amphiphilic polymers based on glycidols. Major advantages are spontaneous self‐assembly in water and the possibility to form onion polymersomes relevant to encapsulation.