Soft nanosystems based on hydroxypiperidinium surfactants as adjuvants and micellar catalysts

1. Download : Download high-res image (99KB)
2. Download : Download full-size image

     

Facile preparation of superhydrophobic coatings by sol-gel processes

Different organic/inorganic compositions and deposition methods were used to prepare superhydrophobic surfaces using metal alkoxides and the sol-gel process. Both surface roughness and composition had to be adjusted in order to obtain very high contact angles and low contact angle hysteresis as a necessary requirement for superhydrophobicity. Multilayer samples with a fluorinated organic-inorganic top layer showed water contact angles of about 157 degrees with low hysteresis (2 degrees ). Water drops rolled easily off their surface at a tilt angle as low as 4 degrees .     

Design,synthesis, and antimicrobial activity of some new pyrazolo[3,4‐d]pyrimidines

2‐Benzyl‐ and 2‐aryloxymethyl‐3‐amino‐1‐phenyl‐pyrazolo[3,4‐d]pyrimidine‐4‐ones 5a–f have been synthesized by reacting the corresponding arylacetylamino derivatives 3a–f with hydrazine hydrate. Thionation of compounds 5d–f by action of P₂S₅ in pyridine yielded 2‐aryloxy‐methyl‐3‐amino‐1‐pheny‐lpyrazolo[3,4‐d]pyrimidin‐4‐thions 6a–c . 2,5‐Diphenyl‐2,3‐dihydro‐1H‐pyrazolo[5′,1′:4:5]pyrazolo[3,4‐d]pyrimidine‐8‐one ( 8 ) was also obtained via reaction of ethyl‐2‐cinnamoylamino‐1‐phenyl‐pyrazole‐4‐car‐boxylate ( 7 ) with hydrazine hydrate. The prepared compounds were screened in vitro for their antimicrobial activity. Some of the tested compounds were found to be active at 100 μg/ml compared with reference compounds (Ampicillin and Trivid) as antibacterial agents and claforan as antifungal agent. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:530–534, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10187     

Self‐Consistent Brownian Dynamics Simulation of an Anisotropic Brush Under Shear Flow

Summary: The behavior of an anisotropic polymer brush under a lateral shear flow is considered in the framework of a hybrid method combining a self‐consistent field approach and Brownian dynamics simulation. It is shown that such a flow can induce the compression of an anisotropic brush at shear rates much smaller than those which induce the compression of a conventional isotropic brush. Moreover, a lateral flow can initiate a thermotropic collapse which occurs as an LC phase transition. This collapse takes place at higher temperatures than in the absence of the flow. This can help to find brush compression experimentally. The variation of the internal structure of a brush (density, order parameter, and director orientation profiles, distribution of terminal groups) is also investigated. An anomalous effect of brush densification and ordering near the outer surface is observed. At large shear rates the distribution of chains over their deformation has a bimodal character: one fraction of chains is strongly stretched and another fraction remains unperturbed by the flow. Average characteristics of a brush were compared with predictions of the lattice theory for the box model where the lateral force is applied to chain ends. Satisfactory agreement was observed.

Polymer brush under an influence of lateral flow.     

Synthesis of some new spiro naphtho[2,3‐d][1,3]dithiole‐4,9‐dione derivatives

2(1‐Acetyl‐2‐oxopropylidene)naphtho[2,3‐d][1,3]dithiole‐4,9‐dione 1 reacts with a variety of bidentates reagents to give some new functionally substituted spiro naphthodithiole‐4,9‐dione derivatives.     

4-Methylamino antipyrine determination in human plasma by high-performance liquid chromatography tandem mass spectrometry

In the present study, a simple and rapid method for metamizole metabolite 4-methylamino antipyrine (MAA) determination in human plasma was developed, validated and successfully applied to a clinical trial. Chromatographic separation was achieved in HILIC mode on a YMC-Pack SIL column (100 × 2.0 mm; S-5 μm, 30 nm), with a mobile phase consisting of acetonitrile, water and formic acid. Protein precipitation of a small plasma volume using acetonitrile was selected for sample preparation. The multiple reaction monitoring transitions in the positive ionization mode were m/z 218.2 → 56.2 for MAA and m/z 221.2 → 56.2 for MAA-d3 (IS, internal standard). Concentration levels of MAA calibration standards were in the range of 0.100–20 μg/ml. Metamizole conversion into MAA in both water and organic media was investigated, and the level of the conversion in commercially available injection solutions was estimated.