Superparamagnetic Composites Based on Ionic Resin Beads/CaCO3/Magnetite

The preparation of superparamagnetic composites obtained by CaCO₃ mineralization from supersaturate aqueous solutions is presented. The preparation was conducted in the presence of oleic acid stabilized magnetite nanoparticles as a water‐based magnetic fluid and insoluble templates as gel‐like cross‐linked polymeric beads. The presence of the magnetic particles in the composites provides a facile way for external manipulation using a permanent magnet, thus allowing the separation and extraction of magnetically modified materials. Two ion exchangers based on divinylbenzene/ethyl acrylate/acrylonitrile cross‐linked copolymer—a cation ion exchanger (CIE) and an amphoteric ion exchanger (AIE)—were used, as well as different addition orders of magnetite and CaCO₃ crystals growth precursors. The morphology of the composites was investigated by SEM, the polymorphs content by X‐ray diffraction, and the thermal stability by thermogravimetric analysis. Polymer, CaCO₃, and magnetite in the composite particles were shown to be present by energy dispersive X‐ray (EDX), XPS, and TEM. The sorption capacity for Cu^II ions was tested, as compared to samples prepared without magnetite.     

Carbohydrates as Additives for the Formation of Isoporous PS‐b‐P4VP Diblock Copolymer Membranes

Highly porous polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) diblock copolymer membranes are prepared using carbohydrates as additives. Therefore α‐cyclodextrine, α‐(D )‐glucose, and saccharose (cane sugar) are tested for the membrane formation of three different PS‐b‐P4VP polymers. The addition of the carbohydrates leads to an increasing viscosity of the membrane solutions due to hydrogen bonding between hydroxyl groups of the carbohydrates and pyridine units of the block copolymer. In all cases, the membranes made from solution with carbohydrates have higher porosity, an improved narrow pore distribution on the surface and a higher water flux as membranes made without carbohydrates with the same polymer, solvent ratio, and polymer concentration.     

Essential spectrum of the weighted Laplacian on noncompact manifolds and applications

We obtain upper estimates for the bottom (that is, greatest lower bound) of the essential spectrum of weighted Laplacian operator of a noncompact weighted manifold under assumptions of the volume growth of their geodesic balls and spheres. Furthermore, we find examples where the equality occurs in the estimates obtained. As a consequence, we give estimates for the weighted mean curvature of complete noncompact hypersurfaces into weighted manifolds.     

Altered Glycosylation of Human Alpha-1-Acid Glycoprotein as a Biomarker for Malignant Melanoma

A high-resolution HILIC-MS/MS method was developed to analyze anthranilic acid derivatives of N-glycans released from human serum alpha-1-acid glycoprotein (AGP). The method was applied to samples obtained from 18 patients suffering from high-risk malignant melanoma as well as 19 healthy individuals. It enabled the identification of 102 glycan isomers separating isomers that differ only in sialic acid linkage (α-2,3, α-2,6) or in fucose positions (core, antenna). Comparative assessment of the samples revealed that upregulation of certain fucosylated glycans and downregulation of their nonfucosylated counterparts occurred in cancer patients. An increased ratio of isomers with more α-2,6-linked sialic acids was also observed. Linear discriminant analysis (LDA) combining 10 variables with the highest discriminatory power was employed to categorize the samples based on their glycosylation pattern. The performance of the method was tested by cross-validation, resulting in an overall classification success rate of 96.7%. The approach presented here is significantly superior to serological marker S100B protein in terms of sensitivity and negative predictive power in the population studied. Therefore, it may effectively support the diagnosis of malignant melanoma as a biomarker.     

Manufacturing and Assessing the New Orally Disintegrating Tablets,Containing Nimodipine-hydroxypropyl-β-cyclodextrin and Nimodipine-methyl-β-cyclodextrin Inclusion Complexes

The aim of the present study was to manufacture new orally disintegrating tablets containing nimodipine–hydroxypropyl-β-cyclodextrin and nimodipine–methyl-β-cyclodextrin inclusion complexes. For obtaining a better quality of the manufactured tablets, three methods of the preparation of inclusion complexes, in a 1:1 molar ratio, were used comparatively; namely, a solid-state kneading method and two liquid state coprecipitation and lyophilization techniques. The physical and chemical properties of the obtained inclusion complexes, as well as their physical mixtures, were investigated using Fourier transformed infrared spectroscopy, scanning electron microscopy, X-ray diffraction analyses, and differential scanning calorimetry. The results showed that the lyophilization method can be successfully used for a better complexation. Finally, the formulation and precompression studies for tablets for oral dispersion, containing Nim–HP-β-CD and Nim–Me-β-CD inclusion complexes, were successfully assessed.     

Isonitrile derivatives of polyacrylamide as supports for the immobilization of biomolecules

Isonitrile derivatives of crosslinked polyacrylamide beads (Biogell P-100) were prepared by a two-step procedure: a. N-hydroxymethylation (methylolation) of amide groups on the polymer by treatment with formaldehyde; and b. Attachment of side chains, containing isonitrile functional groups by a displacement reaction involving 1-tosyloxy-3-isocyanopropane (p-CH₃-C₆H₄·SO₂·O·(CH₂)₃ NC) and alkoxide ions generated on methylolated polyacrylamide by treatment with a strong base in a polar aprotic solvent. The modified polyacrylamide beads were tested as support for the immobilization of proteins, and low mol wt ligands by four component condensation (4CC) reactions. Trypsin-polyacrylamide acting on N-benzoyl-L-arginine ethylester exhibited nonlinear Michaelis Menten kinetics and distorted pH activity profiles. The kinetic anomalies could be reduced by increasing the concentration of buffer. The data were consistent with a model assuming “buffer facilitated proton transport” in a diffusionally constrained system.     

A convenient and simple procedure for the preparation of nitrate esters from alcohols employing LiNO3/(CF3CO)2O

Alcohols in small peptides, monosaccharides and steroids (12 examples) are conveniently transformed to their corresponding nitrate esters upon treatment with an acetonitrile solution of LiNO₃ and trifluoroacetic anhydride. The in situ formed mixed anhydride (CF₃COONO₂) is proposed to be the reactive nitration reagent.     

Distribution and Excretion of Radiolabeled Temoporfin in a Murine Tumor Model

The biodistribution and excretion of temoporfin (tetra[ m -hydroxyphenyl]chlorin, m -THPC), a recently developed photosensitizer, was investigated in BALB/c mice. [¹⁴C]temoporfin was administered intravenously (0.73 μmol/kg) to tumor-free mice or to mice implanted with the Colo 26 colorectal carcinoma. Blood, tissue and fecal samples were collected for 35 days and 10 days postdose from tumor-free mice and tumor-bearing mice, respectively. Blood concentrations fell rapidly such that at later time points they were indistinguishable from background counts. Tumor concentrations rose to a peak of 0.34 μg temoporfin equivalents/mL at 2 days and then declined in parallel (log plot) with the blood concentrations. Tumor : tissue ratios at 2 days for skin, adipose tissue and skeletal muscle underlying the tumor were 1.5, 2.3 and 3.8, respectively. By 4 days the corresponding values were 1.6, 3.4 and 4.0. Nearly 40% of the administered radioactivity was excreted in the feces in the first 24 h and more than 80% had been excreted by 20 days. Less than 0.2 % of the dose was recovered from the urine. An elimination half-life of 10–12 days was calculated from the excretion data.     

Alkylated polyethyleneimine/polyoxometalate synzymes as catalysts for the oxidation of hydrophobic substrates in water with hydrogen peroxide

Combinations of alkylated polyethylenimine and polyoxometalates yield water-soluble synzymes with hydrophobic regions that allowed the aqueous biphasic selective oxidation of very hydrophobic, water-insoluble substrates with hydrogen peroxide. With the alkylated PEI/{PO4[WO(O2)2]4}3- highly effective C-C bond cleavage of alkenes to aldheydes was observed. The synzymes have both tertiary and quaternary amine centers as shown by a combination of 15N-1H HMBC and XPS measurements. The existence of hydrophobic regions was concluded from the measurement of contact angles and a hypsochromic shift of a fluorescent probe.