On the microbial reduction of ethyl α-methylacetoacetate

In the present work several microorganisms were screened in the reduction of methyl and ethyl acetoacetates. Good to excellent ees were obtained with up to quantitative substrate conversions. These microorganisms were also tested in the reduction of ethyl α-methylacetoacetate with good des and excellent ees. It was noticed that Kluyveromyces marxianus and Trichoderma harzianum were found to lead to products of opposite configuration with the use of methyl or ethyl acetoacetates, which is a very unusual finding.     

Synthesis and characterization of diorganotin(IV) complexes of Schiff bases with ONO‐type donors and crystal structure of [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐ethoxysalicylideneiminato]diphenyltin(IV)

A series of neutral complexes, namely, [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐hydroxysalicylideneiminato]‐ diphenyltin(IV) ( Ia ), [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐methoxysalicylideneiminato]diphenyltin(IV) ( IIa ) and [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐ethoxysalicylideneiminato]diphenyltin(IV) ( IIIa ) were prepared by the reaction of diphenyltin dichloride on the corresponding Schiff bases. The Schiff bases were the reaction products of 2‐hydroxy‐4‐nitroaniline and appropriate salicylaldehydes. All the compounds were characterized by elemental analysis, ¹H‐NMR, ¹³C‐NMR, IR and mass spectroscopy. Compound IIIa was also characterized by single crystal X‐ray diffraction and shows a C₂NO₂ coordination geometry nearly half‐way between a trigonal bipyramidal and square pyramidal arrangement. In the solid state, π? π interactions exist between the aniline fragments of neighbouring molecules. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and microwave‐assisted catalytic activity of novel bis‐benzimidazole salts bearing furfuryl and thenyl moieties in Heck and Suzuki cross‐coupling reactions

A mixture of bis‐benzimidazole salts ( 1–7 ), Pd(OAc)₂ and K₂CO₃ in DMF ? H₂O catalyzes, in high yield, the Suzuki and Heck cross‐coupling reactions assisted by microwave irradiation in a short time. In particular, the yields of the Heck and Suzuki reactions with aryl bromides were found to be nearly quantative. The synthesized bis‐benzimidazole salts ( 1 – 7 ) were identified by ¹H? ¹³C NMR, IR spectroscopic methods and micro analysis. Copyright © 2010 John Wiley & Sons, Ltd.     

Lebesgue and co-Lebesgue di-uniform texture spaces

The author introduces the notions of Lebesgue di-uniformity and co Lebesgue di-uniformity and investigates the relationship between a Lebesgue quasi uniformity on X and the corresponding Lebesgue di-uniformity on the discrete texture (X,P(X)). Finally a notion of a dual dicovering Lebesgue quasi di-uniform texture space is introduced and several properties are discussed.     

Bone repair using mineral trioxide aggregate combined to a material carrier, associated or not with calcium hydroxide in bone defects

Mineral trioxide aggregate (MTA) is a powder aggregate containing mineral oxides with a good biological action and may facilitate the regeneration of the periodontal ligament and formation of bone. Calcium hydroxide demonstrates antibacterial properties, enhances tissue dissolution, and induces bone formation. The objective of this study was to evaluate the MTA in the bone healing process and verify if the calcium hydroxide P.A. can improve and accelerate this process. It was used forty male Wistar rats, which were divided into two groups, considering or not the use of calcium hydroxide P.A. solution before treatment. Thus, each one of these groups was divided in four groups with five animals each, according to the treatment and the defect filled by: animal's coagulum, monoolein gel, MTA in aqueous solution, and MTA combined with monoolein gel. After 10 days, the animals were perfused and the right hemimandibles removed for histological analysis. Statistical analysis of the data showed significant difference between all analyzed groups when it was made comparisons using or not calcium hydroxide P.A. (p<0.0001). There was found statistical difference between the groups that was inserted or not MTA, independently the calcium hydroxide application (p<0.05). Results showed that the MTA used was able to induce bone regeneration and had its action optimized when combined to calcium hydroxide P.A.     

Bone healing process in critical-sized defects by rhBMP-2 using poloxamer gel and collagen sponge as carriers

The bone morphogenetic protein type 2, is an osteoinduction protein, but new carriers to improve its actions are being studied in recent researches. The objective of this study was to evaluate the poloxamer gel as potential carrier of the rhBMP-2 during the bone healing process and verify if the collagen sponge can improve this process. Fifty-six male Wistar rats were used, which were divided into two groups, considering two periods of time. Thus, each one of these groups was divided in four groups with seven animals each, according to the treatment and the defect filled by 4 microg rhBMP-2 in aqueous solution, 4 microg rhBMP-2 in aqueous solution+collagen sponge, 4 microg rhBMP-2 combined with poloxamer gel, and 4 microg rhBMP-2 combined with poloxamer gel+collagen sponge. After 2 and 4 weeks, respectively, animals were perfused and the hemi-mandibles removed for histological analysis. Statistical analysis of the data showed significant difference between all analyzed groups (p<0.01), and between the periods of time (p=0.0118). There was no interaction between the applied treatment and considered periods of time (p=0.642). Results showed that the rhBMP-2 used in this study was able to induce bone regeneration and had its action optimized when combined to the used carriers, being the bone repair time-dependent.     

Herstellung von Derivaten des Pyridoxins,insbesondere dessen Schwefelanaloga

Zusammenfassung Durch Einwirken von Thioharnstoff, Phosphorpentasulid bzw. thioessigsaurem Kalium auf Pyridoxin oder dessen Derivate wurden Schwefelanaloga von Pyridoxol, Pyridoxamin und 4-Desoxypyridoxin hergestellt und die Ultraviolett-absorptionsspektren dieser Derivate in saurer und alkalischer Lösung gemessen.Mit 2 Abbildungen     

Studying structural,morphological and optical properties of nanocrystalline ZnO:Ag films prepared by sol–gel method for antimicrobial activity

Pure and Ag-doped zinc oxide sol–gel thin films were prepared by spin-coating process. Pure and Ag–ZnO films, containing 2–8% Ag, were annealed at 500?°C for 2?h. All thin films were prepared and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV–visible spectroscopy. X-ray diffraction studies show the polycrystalline nature with hexagonal wurtzite structure of ZnO and Ag:ZnO thin films. The crystallite size of the prepared samples reduced with increasing Ag doping concentrations. AFM and SEM results indicated that the average crystallite size decreased as Ag doping concentration increased. The transmittance spectra were then recorded at wavelengths ranging from 300 to 1000?nm. The films produced yielded high transmission at visible regions. The optical band gap energy of spin-coated films also decreased as Ag doping concentration increased. In particular, their optical band gap energies were 3.75, 3.55, 3.4, 3.3, and 3.23?eV at 0%, 2%, 4%, 6%, and 8%, respectively. Antibacterial activity of pure and Ag-doped zinc oxide against Escherichia coli and Staphylococcus aureus was evaluated by international recognized test (JIS Z 2801). The results showed that pure and Ag-doped ZnO thin film has an antibacterial inhibition zone against E. coli and S. aureus. Gram-positive bacteria seemed to be more resistant to pure and Ag-doped ZnO thin film than gram-negative bacteria. The test shows incrementally increasing in antibacterial activity of the thin films when dopant ratio increased under UV light.

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