A study of reversible gamma-induced structural transformations in vitreous Ge23.5Sb11.8S64.7 by high-resolution X-ray photoelectron spectroscopy

The structural origin of reversible gamma-induced effects in vitreous Ge(23.5)Sb(11.8)S(64.7) has been investigated by high-resolution X-ray photoelectron spectroscopy (XPS). The changes in valence band spectrum from gamma-irradiation suggest a decrease of sulfur lone pair electron concentration accompanied by changes in bonding states of S and Ge. The appearance of additional doublets in the core-level XPS spectra of Ge, Sb, and S atoms for gamma-irradiated sample is described by the formation of over- and under-coordinated charged defect pairs (Ge(3)(-)-S(3)(+)) as a result of radiation treatment. The results verify the switching of Ge-S covalent bonds into S-S bonds as the main microstructural mechanism for gamma-induced optical effects in this glass.     

Formation of Hollow Polymeric Microspheres with Functionalized Surface on the Basis of Latex Particles with Multilayered Structure

Summary: Latices with “core-shell” particle morphology containing polar “core” and a shell on the basis of copolymer of styrene and functional vinyl monomer (allyl alcohol, vinyl acetate, methacrylic acid) has been obtained as a result of graft-copolymerization initiated from the surface of (meth)acrylate latex particles previously modified with functional polyperoxides. The processes of functional shell grafting as well as the processes of latex particle swelling with obtaining hollow microspheres due to neutralization of core carboxylic groups have been studied.     

Biomolecule Release from Alginate Composite Hydrogels Triggered by Logically Processed Signals

Alginate composite hydrogels that exhibit highly sensitive stimuli-responsive behavior were used for signal-stimulated release of pre-loaded insulin. The alginate pores, particularly located at the periphery, were blocked by interpenetration of polyvinyl alcohol (PVA) cross-linked with 1,3-benzenediboronic acid (IPN), thus, significantly reducing uncontrolled leakage of the entrapped biomolecules. The beads were loaded with insulin and various enzymes mimicking different Boolean logic gates (AND, OR, NOR, IMP, INHIB). The enzymes were activated with biologically relevant input signals applied in four logic combinations: 0 , 0 ; 1 , 0 ; 0 , 1 ; 1 , 1 , having the production of H₂O₂ as the result of the biocatalytic reactions. The “successful” combination of the input signals leading to the H₂O₂ production was different for different logic gates, following the corresponding truth tables of the logic gates. When H₂O₂ was produced, boronate ester bonds were oxidized and the IPN was irreversibly degraded, thus re-opening the original pores of the hydrogel. This process allowed release of insulin from the alginate beads. The smart soft material that we have developed tackled well-known limitations of these systems and it may prove valuable in future medical diagnostics or treatments.     

Adjoints and Monads Related to Compact Lattices and Compact Lawson Idempotent Semimodules

For compact Hausdorff Lawson lattices L that are idempotent semirings with lower semicontinuous multiplications, free compact Hausdorff Lawson L-idempotent semimodules are constructed over compacta and over compact Hausdorff Lawson lower semilattices. It is shown that these free objects are spaces of L-valued regular measures. Related left adjoint functors and monads are described.     

Heterometallic mixed-valence complex with a {CoIICoIIICu2O4} core as a new type of cobalt-based oxide cubane

A tetranuclear heterometallic complex formulated as [Co₂Cu₂(L)₃(ea)(H₂O)(NCS)₂], where H₂L = 2-((2-hydroxyethyl)iminomethyl)-phenol and Hea = 2-aminoethanol, has been obtained by self-assembly and characterized by single crystal X-ray diffraction. The crystal structure of the complex represents a new {Co^IICo^IIIM₂} type of cobalt-based oxide cubane complex according to the classification which has been made via CSD structural analysis.     

1-Azaspiro[3.3]heptane as a Bioisostere of Piperidine**

1-Azaspiro[3.3]heptanes were synthesized, characterized, and validated biologically as bioisosteres of piperidine. The key synthesis step was thermal [2+2] cycloaddition between endocyclic alkenes and the Graf isocyanate, ClO₂S−NCO, to give spirocyclic β-lactams. Reduction of the β-lactam ring with alane produced 1-azaspiro[3.3]heptanes. Incorporation of this core into the anesthetic drug bupivacaine instead of the piperidine fragment resulted in a new patent-free analogue with high activity.     

Synthesis,Antibacterial and Antifungal Activity of New 3-Aryl-5H-pyrrolo[1,2-a]imidazole and 5H-Imidazo[1,2-a]azepine Quaternary Salts

A series of novel 3-aryl-5H-pyrrolo[1,2-a]imidazole and 5H-imidazo[1,2-a]azepine quaternary salts were synthesized in 58–85% yields via the reaction of 3-aryl-6, 7-dihydro-5H-pyrrolo[1,2-a]imidazoles or 3-aryl-6,7,8,9-tetrahydro-5H-imidazo[1,2-a]azepines and various alkylating reagents. All compounds were characterized by ¹H NMR, ¹³C NMR, and LC-MS. The conducted screening studies of the in vitro antimicrobial activity of the new quaternary salts derivatives established that 15 of the 18 newly synthesized compounds show antibacterial and antifungal activity. Synthesized 3-(3,4-dichlorohenyl)-1-[(4-phenoxyphenylcarbamoyl)-methyl]-6,7-dihydro-5H-pyrrolo[1,2-a]imidazol-1-ium chloride 6c possessed a broad activity spectrum towards Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Cryptococcus neoformans, with a high hemolytic activity against human red blood cells and cytotoxicity against HEK-293. However, compound 6c is characterized by a low in vivo toxicity in mice (LD₅₀ > 2000 mg/kg).     

Effect of oxidation of nitride coatings on corrosion properties of Ti-6Al-4V alloy in 0.9% NaCl at 40°C

The corrosion properties of Ti-6Al-4V alloy with oxidized thermodiffusion nitride coatings were investigated in isotonic 0.9% solution of NaCl at temperature of 40°C. It was shown that modification of nitride coatings by oxygen leads to a deterioration of the protective properties of nitrided surface of Ti-6Al-4V alloy. The protective properties of the alloy with nitride coatings modified by oxygen are determined by the composition of formed surface oxynitride film.      

Representing measures and infinite-dimensional holomorphy

We consider some applications of the Bishop-De Leeuw Theorem about representing measures for some algebras of analytic functions on unit balls of Banach spaces. In particular, we investigate Hardy spaces H² associated with corresponding algebras. Some examples are considered.