Rapidly self-deoxygenating controlled radical polymerization in water via in situ disproportionation of Cu(i)

Rapidly self-deoxygenating Cu-RDRP in aqueous media is investigated. The disproportionation of Cu(i)/Me₆Tren in water towards Cu(ii) and highly reactive Cu(0) leads to O₂-free reaction environments within the first seconds of the reaction, even when the reaction takes place in the open-air. By leveraging this significantly fast O₂-reducing activity of the disproportionation reaction, a range of well-defined water-soluble polymers with narrow dispersity are attained in a few minutes or less. This methodology provides the ability to prepare block copolymers via sequential monomer addition with little evidence for chain termination over the lifetime of the polymerization and allows for the synthesis of star-shaped polymers with the use of multi-functional initiators. The mechanism of self-deoxygenation is elucidated with the use of various characterization tools, and the species that participate in the rapid oxygen consumption is identified and discussed in detail.

The rapidly self-deoxygenating Cu-RDRP in aqueous media is investigated.     

Cohen-Macaulay Local Rings of Embedding Dimension e + d - 3

In this paper we determine the possible Hilbert functions ofa Cohen–Macaulay local ring of dimension d and multiplicitye, in the case where the embedding dimension v satisfies v =e + d – 3 and the Cohen–Macaulay type is less thanor equal to e – 3. 1991 Mathematics Subject Classification:primary 13D40; secondary 13P99.     

Solvent-free synthesis of nitrones in a ball-mill

Various C-aryl and C-alkyl-nitrones were synthesized within 0.5–2 h via condensation of an equimolar amount of aldehydes and N-substituted-hydroxylamines under solvent-free conditions in a ball-mill apparatus. Reactions can be performed without the need of excluding air and moisture and yields the expected products with no need for further purification. The study has been complemented by Differential Scanning Calorimetry (DSC) and solid-state ¹³C MAS nuclear magnetic resonance experiments. We have also studied the temperature profile during the reaction. A comparative study with the corresponding solvent-free microwave activated reaction showed the superiority of the ball-milling method; 31 examples are described, including the synthesis of the anti-aging agent C-phenyl-N-tert-butyl nitrone (PBN) and one of its analogues C-2-pyridyl-N-tert-butylnitrone (2-PyBN).     

On the rate of points in projective spaces

The rate of a standard gradedK-algebraR is a measure of the growth of the shifts in a minimal free resolution ofK as anR-module. It is known that rate(R)=1 if and only ifR is Koszul and that rate(R) ≥m(I)−1 wherem(I) denotes the highest degree of a generator of the defining idealI ofR. We show that the rate of the coordinate ring of certain sets of pointsX of the projective space P ⁿ is equal tom(I)−1. This extends a theorem of Kempf. We study also the rate of algebras defined by a space of forms of some fixed degreed and of small codimension.     

Synthesis of a new hydrophilic poly(ethylene glycol)-ionic liquid and its application in peptide synthesis

The synthesis of a new hydrophilic ammonium-based poly(ethylene glycol)-ionic liquid (PEG-IL) is reported; the structure was assigned by NMR ((1)H, (13)C) and MALDI mass spectrometry. The viscosity and thermal stability were also studied, as well as its polarity. Its application as an alternative solvent in the synthesis of dipeptides under microwave irradiation is also described.     

Electron capture and loss in the scattering of H+ from HOPG graphite

In this paper we report measurements of the positive (H⁺) and negative (H^?) ion fractions after H⁺ scattering from a highly oriented pyrolytic graphite (HOPG) surface. The experimental results show that for a fixed (large) exit angle the negative fraction is almost independent of the primary ion energy, while the positive fraction increases steadily. For a fixed incident energy, the H⁺ and H^? fractions show a complementary behavior with exit angle. A dynamical quantum mechanical calculation, based on the localized and extended features of the atom–surface interaction, allows us to understand many of the features of the experimental results.     

Antioxidant activity of methimazole-copper(II) bioactive species and spectroscopic investigations on the mechanism of its interaction with Bovine Serum Albumin

Free radical-mediated oxidative stress has been implicated in numerous autoimmune disorders including Graves’ disease. Hyperthyroidism results in a marked increase in intracellular antioxidant enzymes including superoxide dismutase. The later activity is significantly increased in untreated Graves’ patients while treatment with methimazole results in normalization of the free radical and antioxidant activity indices. In this context, and considering the findings mentioned above, the aim of the present study was to evaluate unknown biological activities of methimazole and its methimazole-copper(II) complex investigating their superoxide scavenger power. Under the applied experimental conditions, methimazole did not show superoxide dismutase (SOD) activity while the copper complexes exhibited a strong superoxide radical scavenging capacity. Bearing in mind that the capacity of drugs to bind and/or interact with albumin is essential for their pharmacokinetic and pharmacodynamic properties, a complete investigation of the binding ability of both compounds by using Fourier transform infrared (FT-IR), Raman and Fluorescence spectroscopies, and UV-Vis spectrophotometry was included. Besides, in order to probe the copper ligand environment the EPR spectra of such compounds were analyzed.