Reaction of Diphenyldiazomethane with Phosphorus Monothioacids

The mechanism of the reaction of phosphorus monothioacids with diaryldiazomethanes was studied in different solvent systems at 20 °c. The thiolo to thiono product ratios were determined by 1H NMR spectroscopy and g.l.c. of the reaction mixtures. The results imply that the reaction involves two competing processes leading to the corresponding S- and 0-isomeric esters

The Impact of One Heat Treated Contact Element on the Coefficient of Static Friction

The subject of the paper includes theoretical considerations, the conducting of experimental tests, and the analysis of exposed test results related to determination of the coefficient of static friction of previously heat-treated contact pairs. One contact element is previously, before the procedure of determining the coefficient of static friction, heated at temperatures in the range of ambient temperature to 280°C and then cooled down to ambient temperature. The results of experimental tests of five different materials show that depending on the heat treatment of one contact element, there is a significant decrease in the coefficient of static friction. The authors of the paper consider that the reasons for the decreasing coefficient of static friction are related to oxide formation and changes in the surface layer of the contact element which is previously heat-treated

Identification of material parameters based on Mohr-Coulomb failure criterion for bisphosphonate treated canine vertebral cancellous bone

Nanoindentation has been widely used to study bone tissue mechanical properties. The common method and equations for analyzing nanoindentation, developed by Oliver and Pharr, are based on the assumption that the material is linearly elastic. In the present study, we adjusted the constraint of linearly elastic behavior and use nonlinear finite element analysis to determine the change in cancellous bone material properties caused by bisphosphonate treatment, based on an isotropic form of the Mohr–Coulomb failure model. Thirty-three canine lumbar vertebrae were used in this study. The dogs were treated daily for 1 year with oral doses of alendronate, risedronate, or saline vehicle at doses consistent, on a mg/kg basis, to those used clinically for the treatment of post-menopausal osteoporosis. Two sets of elastic modulus and hardness values were calculated for each specimen using the Continuous Stiffness Measurement (CSM) method (ECSM and HCSM) from the loading segment and the Oliver–Pharr method (EO–P and HO–P) from the unloading segment, respectively. Young's modulus (EFE), cohesion (c), and friction angle (ϕ) were identified using a finite element model for each nanoindentation. The bone material properties were compared among groups and between methods for property identification. Bisphosphonate treatment had a significant effect on several of the material parameters. In particular, Oliver–Pharr hardness was larger for both the risedronate- and alendronate-treated groups compared to vehicle and the Mohr–Coulomb cohesion was larger for the risedronate-treated compared to vehicle. This result suggests that bisphosphonate treatment increases the hardness and shear strength of bone tissue. Shear strength was linearly predicted by modulus and hardness measured by the Oliver–Pharr method (r2 = 0.99). These results show that bisphosphonate-induced changes in Mohr–Coulomb material properties, including tissue shear cohesive strength, can be accurately calculated from Oliver–Pharr measurements of Young's modulus and hardness

Synthesis, characterization, HSA/DNA interactions and antitumor activity of new [Ru(η6-p-cymene)Cl2(L)] complexes

Three new ruthenium(II) complexes were synthesized from different substituted isothiazole ligands 5-(methylamino)-3-pyrrolidine-1-ylisothiazole-4-carbonitrile (1), 5-(methylamino)-3- (4-methylpiperazine-1-yl)isothiazole-4-carbonitrile (2) and 5-(methylamino)-3-morpholine-4- ylisothiazole-4-carbonitrile (3): [Ru(η6-p-cymene)Cl2(L1)]·H2O (4), [Ru(η6 -pcymene)Cl2(L2)] (5) and [Ru(η6-p-cymene)Cl2(L3)] (6). All complexes were characterized by IR, UV-Vis, NMR spectroscopy, and elemental analysis. The molecular structures of all ligands and complexes 4 and 6 were determined by an X-ray. The results of the interactions of CT-DNA (calf thymus deoxyribonucleic acid) and HSA (human serum albumin) with ruthenium (II) complexes reveal that complex 4 binds well to CT-DNA and HSA. Kinetic and thermodynamic parameters for the reaction between complex and HSA confirmed the associative mode of interaction. The results of Quantum mechanics (QM) modelling and docking experiments toward DNA dodecamer and HSA support the strongest binding of the complex 4 to DNA major groove, as well as its binding to IIa domain of HSA with the lowest ΔG energy, which agrees with the solution studies. The modified GOLD docking results are indicative for Ru(p-cymene)LCl··(HSA··GLU292) binding and GOLD/MOPAC(QM) docking/modelling of DNA/Ligand (Ru(II)-N(7)dG7) covalent binding. The cytotoxic activity of compounds was evaluated by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl2H-tetrazolium bromide) assay. Neither of the tested compounds shows activity against a healthy MRC-5 cell line while the MCF-7 cell line is the most sensitive to all. Compounds 3, 4 and 5 were about two times more active than cisplatin, while the antiproliferative activity of 6 was almost the same as with cisplatin. Flow cytometry analysis showed the apoptotic death of the cells with a cell cycle arrest in the subG1 phase

Sinteza, svojstva i primena umreženih makroporoznih kopolimera na bazi metakrilata

In this paper, the results obtained during extensive research on the synthesis, properties and application of cross linked copolymers, performed at the Faculty of Technology and Metallurgy (Department of Physical Chemistry and Electrochemistry) and at the IChTM (Center for Catalysis and Chemical Engineering and Center for Chemistry) are summarized. According to the obtained results, changes in the composition of the inert component and the content, type and amount of the crosslinking agent, as well as the type of copolymerization reaction, all strongly influence the porosity parameters of the synthesized macroporous copolymers. Also, it was shown that the synthesized copolymers of glycidyl methacrylate, GMA, and ethylene glycol dimethacrylate, EGDMA, modified with ethylene diamine can be used for the selective sorption of gold and platinum from mixed solutions containing copper, cobalt and nickel ions.U okviru ovoga rada prikazani su rezultati dobijeni u toku višegodišnjeg izučavanja sinteze, svojstava i primene makroporoznih umreženih kopolimera na bazi metakrilata, koja su obavljena pri Katedri za fizičku hemiju i elektrohemiju Tehnološko-metalurškog fakulteta u Beogradu, Centra za katalizu i hemijsko inženjerstvo i Centra za hemiju Instituta za hemiju, tehnologiju i metalurgiju u Beogradu. Pokazano je da se izmenom sastava i udela inertne komponente, vrste i udela umreživača, kao i načina izvođenja reakcije kopolimerizacije može bitno uticati na parametre porozne strukture sintetizovanih umreženih makroporoznih kopolimera i na taj način njihova svojstva prilagoditi različitim potrebama. Pokazano je takođe da se sintetizovani kopolimeri glicidilmetakrilata i etilenglikoldimetakrilata obrađeni sa etilendiaminom mogu uspešno koristiti za selektivno izdvajanje platine iz mešanih rastvora sa jonima bakra, kobalta i nikla

Sulfasalazine Induced DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome with severe acute hepatitis: Case report

Introduction: Drug Reaction with Eosinophilia and Systemic Symptoms Syndrome is a rare and severe form of drug induced delayed-type hypersensitivity reaction with mortality rate up to 10%. It usually manifests with skin rash, fever, lymphadenopathy, hematological abnormalities and involvement of one or more internal organs. Establishing the diagnosis is sometimes late due to variable clinical presentation. Current recommendations for therapy rely mainly on expert opinions, retrospective studies, case reports and series. Sulfasalazine was firstly synthesized in 1930 and is currently being prescribed for various inflammatory and rheumatic diseases. Case report: We present a 45-year-old patient who was prescribed sulfasalazine tablets by a rheumatologist due to reactive arthritis. In the fourth week of therapy, he developed skin rash and fever up to 39.5°C. On admission, generalized maculopapular exanthema covering over 60% of the body surface area, edema of the lower eyelids and bilateral cervical and inguinal lymphadenomegaly were registered. Laboratory findings showed leukocytosis with significant eosinophilia, lymphocytosis, elevated bilirubin values, ALT <100 U/L, while ultrasonography of the upper abdomen confirmed hepatosplenomegaly. The patient was diagnosed with Drug Reaction with Eosinophilia and Systemic Symptoms Syndrome using RegiSCAR and J-SCAR diagnostic criteria and systemic therapy with methylprednisolone at a dose of 1.5 mg/kg and other supportive therapy was applied, which resulted in complete regression of the skin changes and normalization of laboratory values. Conclusion: The authors would like to recall the occurrence of Drug Reaction with Eosinophilia and Systemic Symptoms Syndrome as a rare and potentially fatal drug reaction in which awareness of this disease is of key importance for early recognition. Identification of the offending drug followed by a prompt withdrawal and subsequent treatment is essential for decreasing disease related morbidity and mortality and thus we wish to familiarize the sulfasalazine prescribers with this syndrome

Mechanical Properties of UV Cured Mixture of Linear and Hyperbranched Urethane Acrylates

Ispitivane su smeše uretan akrilata na bazi linearnog poliestra i dva uretan akrilata, sa istim stepenom akrilovanja, na bazi alifatskih hiperrazgranatih poliestara (HRP). Linearni poliestar sintetisan je od neopentil glikola i adipinske kiseline. HRP treće generacije dobijen je od 2,2- bis(hidroksimetil)propionske kiseline i di-trimetilol propana. Modifikacija 60 % završnih OH grupa HRP-a izvedena je masnim kiselinama sojinog ulja ili izononskom kiselinom. Linearni uretan akrilat (LUA) i hiperrazgranati uretan akrilat (HUA) na bazi HRP modifikovanog masnim kiselinama sojinog ulja i HUA na bazi HRP modifikovanog izononskom kiselinom dobijeni su reakcijom određenog poliestra i izocijanatnog adukta, prethodno dobijenog reakcijom ekvimolarnih količina izoforon diizocijanata i 2-hidroksietil akrilata. Procena mešljivosti smeša LUA i HUA izvršena je na osnovu viskozimetrijskih merenja koristeći metodu koju je ustanovio Chee. Ovako pripremljenim smešama dodato je 20 mas. % heksandioldiakrilata i 4 mas. % fotoinicijatora, Irgacure 184, i umrežene su pod dejstvom UV zračenja. Umreženi uzorci ispitivani su u ogledima dinamičkog uvijanja i jednoosnog istezanja. Mehanička svojstva umreženih uzoraka zavise od mešljivosti komponenata smeše i od njenog sastava.The mixtures of urethane acrylate resin based on linear polyester and two urethane acrylates, with the same degree of acrylation, prepared from partially modified aliphatic hyperbranched polyesters (HBP), were examined. Linear polyester was obtained from neopentil glycol and adipic acid. HBP of the third generation was synthesized from 2,2-bis(hydroxymethyl)propionic acid and ditrimethylol propane. The modification of 60 % OH end-groups of HBP was carried out with soybean fatty acids or isononanoic acid. Linear urethane acrylate (LUA) and hyperbranched urethane acrylate (HUA) based on the HBP modified with soy been faty acid and HUA based on the HBP modified with isononanoic acid were obtained by reaction of appropriate polyester and NCO adduct, previously obtained by reaction of equimolar amount of isophorone diisocyanate and 2-hydroxyethyl acrylate. The miscibility of the prepared mixtures of LUA and HUAs was estimated according to viscosity measurements using the approach developed by Chee. UV curable formulation was obtained by adding hexanediol diacrylate (20 wt. %) and photoinitiator, Irgacure 184, (4 wt. %) to the prepared LUA and HUA mixtures. The UV cured samples were examined by dynamic torsion and uniaxial tension. It was obtained that mechanical properties of the UV cured samples depend on miscibility of mixture’s constituents and on its composition

Influence of alkyl gallate surface modified TiO2 nanoparticles on the rheological properties of alkyd resin

The influence of alkyl gallate surface modified TiO2 nanoparticles on the rheological properties of long oil alkyd resin, based on soybean oil, was investigated. Surface modification of TiO2 nanoparticles, obtained by acid catalyzed hydrolysis of titanium tetraisopropoxide, was performed with propyl, lauryl or cetyl gallate. The average particle size and the crystal structure of synthesized nanoparticles were estimated by transmission electron microscopy and X-ray diffraction. The gallate chemisorption onto surface of TiO2 nanoparticles was confirmed by FTIR and UV spectroscopy. The examined dispersions were prepared by the addition of modified TiO2 nanoparticles to the commercial alkyd resin. The viscosity of the prepared dispersions was higher than viscosity of the pure resin and it increased with increasing length of hydrophobic part of the gallate used for surface modification of TiO2 nanoparticles. This occurred because the increase of their hydrodynamic volume led to the increase of the effective volume fraction of particles in dispersion

Uticaj veličine nanočestica TIO2 i njihove površinske modifikacije na reološka svojstva alkidne smole

Spherical TiO2 particles of different size were dispersed in alkyd resin based on soybean oil. Four samples of TiO2 particles were used, three commercial and one obtained by acid catalyzed hydrolysis of titanium tetraisopropoxide. The size of the synthesized nanoparticles was determined by transmission electron microscopy. Surface modification of TiO2 nanoparticles was performed with propyl gallate and lauryl gallate. The influence of the size of TiO2 nanoparticles, their concentration and type of the surface modification on the rheological properties of alkyd resin was investigated. The obtained results have shown that the viscosity of the prepared dispersions was higher than the viscosity of the pure resin, increases with decreasing particle diameter and decreases with frequency increase. Surface modified particles showed higher influence on the viscosity of alkyd resin than unmodified, because their hydrodynamic volume is higher due to the presence of the adsorbed gallates, leading to the increase of effective volume fraction of particles in dispersion. For the lowest TiO2 concentration, the viscosity was higher for the sample modified with lauryl gallate, due to the higher thickness of the adsorbed layer. The increase of concentration, because of less dispersion stability of the particles modified with propyl gallate, leads to particle agglomeration. The presence of agglomerates, which was confirmed by a change in the slope of the functional dependence of storage modulus on loss modulus, leads to a rapid increase in viscosity.Sferne čestice TiO2 različitih veličina dispergovane su u alkidnoj smoli. Površinska modifikacija nanočestica TiO2 izvedena je propil galatom i lauril galatom. Ispitivan je uticaj veličine nanočestica TiO2, koncentracije, kao i vrste površinske modifikacije na reološka svojstva alkidne smole. Dobijeno je da je viskoznost pripremljenih disperzija veća od viskoznosti čiste smole, da raste sa smanjenjem prečnika čestica i opada sa povećanjem frekvencije. Površinski modifikovane čestice imaju veći uticaj na viskoznost alkidne smole nego nemodifikovane zbog povećanja efektivnog zapreminskog udela čestica u disperziji. Za najmanju koncentraciju TiO2 viskoznost je veća kada je modifikacija izvršena lauril galatom, dok sa povećanjem koncentracije, zbog manje disperzione stabilnosti čestica modifikovanih propil galatom, dolazi do njihove aglomerizacije i naglog povećanja viskoznosti

Structure and Properties of Nanocrystalline Tetragonal BaTiO3 Prepared by Combustion Solid State Synthesis

Barium titanate (BaTiO3) attracts high scientific and technological attention due to good dielectric and electromechanical properties. Although BaTiO3 is one of the most frequently investigated ferroelectric materials, the need for finding new and/or improved synthesis methods of this material still exists. In this paper, a novel, mild synthesis route for producing tetragonal BaTiO3 from barium nitrate and Ti-oxalate precursor is presented. Morphology of the prepared and subsequently sintered BaTiO3 was determined by SEM. Particle size distribution of the as prepared powder was monitored by the laser diffraction. The phase composition, structure and lattice dynamics were investigated by XRD and Raman spectroscopy. Finally, dielectric parameters were determined in the temperature range from 30 to 180 degrees C, and within a variety of frequencies. Curie temperature was detected at 130 degrees C