Pseudo five-component synthesis of bis-α-acyloxy-β-diketo amides from diimide-dicarboxylic acids

Diimide-dicaboxylic acids derived from condensation of α-amino acids with the 2,3,5,6-bicyclo[2.2.2] oct-2-enetetracarboxylic-2,3:5,6-dianhydride or 1,2,4,5- bezenetetracarboxylic-1,2:4,5-dianhydride react with ninhydrin and isocyanides to produce some novel interesting bis-α-acyloxy-β-diketo amides.     

Synthesis and characterization of new polyesters based on 2,5-bis[(4-chloro carboxyanilino) carbonyl] pyridine and aromatic diols

<正>Six new polyesters 7a-f were synthesized through the solution polycondensation reaction of diacid chloride 5 with six aromatic diols 6a-f in N,N-dimethyl acetamide(DMAc) as solvent in the presence of pyridine as base.The polycondensation reaction produced a series of novel polyester containing pyridyl moiety in the main chain in high yields with inherent viscosities between 0.35 and 0.54 dL/g.The resulted polymers were fully characterized by means of FT-IR spectroscopy,elemental analyses,inherent viscosity and solubility tests.Thermal properties of these polymers were investigated by using thermal gravimetric analysis(TGA) and differentional thermal gravimetric(DTG).The glass-transition temperatures of these polyesters were recorded between 130 and 170℃by differential scanning calorimetry(DSC) and the 10%weight loss temperatures were ranging from 390 to 450℃under nitrogen.     

Mouse bone marrow‐derived mesenchymal stem cell response to nanostructured titanium substrates produced by high‐pressure torsion

Mesenchymal stem cells (MSCs) with the ability to differentiate into various mesoderm‐like cells are known to migrate to various organs to repair injured tissues. They can attach to the implant surface, differentiate into bone‐forming cells, and ultimately osseointegrate with the prosthesis. This study investigates bone marrow‐derived mesenchymal stem cellular response to the grain structure of titanium substrates produced by high‐pressure torsion and annealing processes. Cell attachment, proliferation, viability, and morphology are evaluated on the surface of differently processed nanostructured and coarse‐grained samples. The bacterial adhesion and calcium phosphate crystal formation and growth are also assessed on the surface of the substrates. The nanostructured titanium shows significantly higher cell adhesion, proliferation, spreading, and viability compared with the untreated and coarse‐grained titanium substrates. The adhesion of bacteria is lower and surface bioactivity is higher on the surface of the nanostructured titanium substrate. The results demonstrate the superior MSC compatibility, antibacterial efficacy, and surface bioactivity of the nanostructured titanium substrates, which could lead to early implant fixation and improved osseointegration. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis and characterization of organo-soluble poly(amide-imide)s based on 1,2-bis[4-(trimellitimido)phenoxy]ethane and aromatic diamines

<正>New organo-soluble poly(amide-imide)s(PAIs) 8a-8f were prepared from newly synthesized 1,2-bis[4,4'-(trimellitimido) phenoxy]ethane 6 via direct polycondensation with various aromatic diamines.The diacid 6 was synthesized by the condensation reaction of 12-bis[4-atninophenoxy]ethane 4 with trimellitic anhydride 5 in acetic acid.All polymers were obtained in quantitative high yields with inherent viscosities of 0.48-0.61 dL/g.All of these polymers were highly soluble in organic solvents such as,N-methyl-2-pyrrolidone(NMP),dimethylformamide(DMF),N,N'-dimethylacetamide (DMAc) and dimethylsulfoxide(DMSO) at room temperature and were fully characterized by means of NMR spectroscopy, FTIR spectroscopy,elemental analyses,inherent viscosity,solubility test,specific rotation,differential scanning calorimetry (DSC) and thermogravimetric analysis(TGA).     

Synthesis and characterization of new optically active copoly(amid-imide)s based on N-phthalimido-L-aspartic acid and aromatic diamines

<正>In this article,six new optically active copoly(amide-imide)s(10a-f) were synthesized through the direct polycondensation reaction of N-phthalimido-L-aspartic acid(4) with 1,5-diamino naphthalene(8),3,4-diamino benzophenone(9) in the presence of therphthahc acid(7),fumaric acid(6) and adipic acid(5) as a second diacid in a medium consisting of N-methyl-2-pyrrolidone,triphenyl phosphite, calcium chloride and pyridine.The resulting copolymers were fully characterized by means of FT-IR spectroscopy,elemental analyses, inherent viscosity,solubility tests and UV-vis spectroscopy.Thermal properties of resulting copolymers(10a-c) containing three different second diacid in the main chain were compared by using TGA and DTG thermograms.     

Investigation of the dose rate dependency of the PAGAT gel dosimeter at low dose rates

Medical physicists need dosimeters such as gel dosimeters capable of determining three-dimensional dose distributions with high spatial resolution. To date, in combination with magnetic resonance imaging (MRI), polyacrylamide gel (PAG) polymers are the most promising gel dosimetry systems. The purpose of this work was to investigate the dose rate dependency of the PAGAT gel dosimeter at low dose rates. The gel dosimeter was used for measurement of the dose distribution around a Cs-137 source from a brachytherapy LDR source to have a range of dose rates from 0.97 Gy h^?1 to 0.06 Gy h^?1. After irradiation of the PAGAT gel, it was observed that the dose measured by gel dosimetry was almost the same at different distances (different dose rates) from the source, although the points nearer the source had been expected to receive greater doses. Therefore, it was suspected that the PAGAT gel is dose rate dependent at low dose rates. To test this further, three other sets of measurements were performed by placing vials containing gel at different distances from a Cs-137 source. In the first two measurements, several plastic vials were exposed to equal doses at different dose rates. An ionization chamber was used to measure the dose rate at each distance. In addition, three TLD chips were simultaneously irradiated in order to verify the dose to each vial. In the third measurement, to test the oxygen diffusion through plastic vials, the experiment was repeated again using plastic vials in a nitrogen box and glass vials. The study indicates that oxygen diffusion through plastic vials for dose rates lower than 2 Gy h^?1 would affect the gel dosimeter response and it is suggested that the plastic vials or (phantoms) in an oxygen free environment or glass vials should be used for the dosimetry of low dose rate sources using PAGAT gel to avoid oxygen diffusion through the vials.     

Minimal generalized permutations

In this paper, we obtain the number of the minimal generalized permutations on a finite set. Also, we determine the minimal generalized permutations on a setX of cardinality less than or equal to 4.     

Applications of heteropoly acids in multi-component reactions

The present review covers the advances and applications of Keggin, Wells-Dawson, and Preyssler types of heteropoly acids as the green, recyclable, and efficient solid-acid catalysts in multi-component reactions.     

Biocorrosion and biocompatibility of Zr–Cu–Fe–Al bulk metallic glasses

Owing to their unique chemo‐physical and structural characteristics, amorphous bulk metallic glasses (BMGs) are of great demand for fabrication of variety of advanced and innovative products including surgical and biomedical tools and devices. In this study, a series of Ni‐free Zr‐based BMGs in Zr–Cu–Fe–Al system are fabricated using copper‐mold casting technique, and their biocorrosion and biocompatibility are evaluated with respect to their corrosion behavior in the phosphate buffered saline (pH = 7.4) solution. Anodic polarization curves, scanning electron microscopy combined with energy‐dispersive X‐ray, and wettability analyses are conducted to characterize the surfaces of BMG samples. The biocompatibility of the BMG and control samples is studied by comparing cell–substrate interactions among different samples. It is found that Zr₆₀Cu₂₀Fe₁₀Al₁₀ displays a higher passive region compared with that of Zr₆₀Cu_22.5Fe_7.5Al₁₀, but both BMGs exhibit lower corrosion resistance compared with Ti–6Al–4V alloy. By addition of titanium to Zr–Cu–Fe–Al system (Zr₆₀Ti₆Cu₁₉Fe₅Al₁₀), a significant increase in the passive region of the polarization curve is detected. The cell culture experiments reveal that the number of attached and grown cells is significantly higher on the surface of the treated BMGs as compared with Ti–6Al–4V substrates and the culture plate as controls. There is no noticeable difference in cellular morphology among the BMG samples, and no cytotoxicity is detected. We speculate that the interaction of water molecules and matrix proteins with the surfaces of BMGs plays an important role in cell–substrate interactions and improved cell response. Copyright © 2013 John Wiley & Sons, Ltd.