Low-lying (K π = 0+) states of gadolinium isotopes

The sd-interacting boson approximation (sd-IBA) and the df-interacting boson approximation (df-IBA) can be related to each other and the states of the interacting boson approximation model can be identified with the fully symmetric states in the sdf interacting boson approximation model. A systematic study of the sdf-IBA model showed that the constructed Hamiltonian can successfully describe the strong octupole correlations in the deformed nuclei. We showed that the interacting boson approximation may account for many of these K ^π ?=?0⁺ states. It was found that the calculated energy spectra of the gadolinium isotopes agree quite well with the experimental data. The observed B(E2) values were also calculated and compared with the experimental data.     

Three-dimensional blow-up solutions of the Navier-Stokes equations

In this paper we extend the plane blow-up results of Grundy& McLaughlin (1997) to the three-dimensional Navier-Stokes equations.Using a solution structure originally due to Lin we first providenumerical evidence for the existence of blow-up solutions on- < x, z < , 0 y 1 with boundary conditions on y = 0and y = 1 involving derivatives of the velocity components.The formulation enables us to consider plane and radial flowas special cases. Various features of the computations are isolatedand are used to construct a formal asymptotic solution closeto blow-up. We show that the numerical and asymptotic analysesprovide a mutually consistent global picture which supportsthe conclusion that, for the family of problems we considerhere, blow-up in fact can take place in three dimensions butat an inverse linear rate rather than the faster inverse squareof the plane case.     

Development of an analytical microsystem for organic gas detection based on surface acoustic wave resonators

Modified Surface Acoustic Wave (SAW) devices can be used as highly sensitive detectors for gases: coated with a selective sorptive layer, they serve as a frequency determining element of an oscillator circuit. To perform a quantitative analysis of organic gas mixtures with polymer coatings as sensitive membranes, it is necessary to use an array of several SAW sensors with sensitivities towards various gaseous components and a subsequent pattern recognition of the sensor responses. An automatic working, self purging and compact analytical microsystem has been developed for organic gas detection. As the central component it contains an array of nine commercially available SAW resonators working at frequency of 433.92 MHz. Eight sensor oscillators, one common reference oscillator for temperature compensation and circuits for frequency mixing are mounted within a compact radial housing (diameter 108 mm). A selection of polymers has been made to detect a broad variety of gaseous organic analytes. Of particular interest have been hydrocarbons, halogenated hydrocarbons and aromatic compounds. Initial experiments with these analytes have been carried out to proof the selection and to optimize the combination of polymer coatings. With the compact sensor configuration a very fast response time in the range of seconds is obtained for qualitative determination of the analytes.Dedicated to Professor Dr. Dr. h.c. mult. J. F. K. Huber on the occasion of his 70th birthday     

Eine Methode zur Trennung der Phenolcarbonsäuren durch Hochdruck-Flüssigkeits-Chromatographie

Zusammenfassung Es wurde die Trennung von Phenolcarbonsäuren durch Hochdruck-Flüssigkeits-Chromatographie untersucht. Die bisher besten Resultate wurden durch Verteilungs-Chromatographie mit Merckogel Si 150-Trennsäulen erzielt. Als mobile Phasen dienten ternäre Zweiphasengemische. Die Elution wird durch Ansäuern der mobilen Phase beschleunigt. Mit dem beschriebenen System lassen sich auch die cis-trans-Isomeren der p-Cumarsäure und Ferulasäure auftrennen.

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A method for separating phenolic acids by high pressure liquid chromatography

Summary The separation of phenolic acids has been investigated by high-pressure liquid chromatography. Until now the best results have been obtained by partition chromatography with Merckogel Si 150-columns. Ternary two-phase compositions served as mobile phases. Elution is accelerated by acidifying the mobile phase. Also the cis-trans isomers of p-cumaric acid and ferulic acid may be separated with the system described.

     

Long-term retention of ice-nucleating active Pseudomonas fluorescens by overwintering colorado potato beetles

Ice nucleating-active Pseudomonas fluorescens F264C was fed to Colorado potato beetles to determine bacterial retentioin in the beetle gut and its effect on the cold hardiness of this insect pest. The bacrterium was present in beetles recovered after overwintering in the field, seven months after their exposure to P. fluorescens. Retention was evident not only in the detection of the P. fluorescens ice nucleating gene, inaW, in bacterial cultures from beetle guts but also in the elevated supercooling points of some treated beetles.     

The Chemistry of Cyborgs—Interfacing Technical Devices with Organisms

The term “cyborg” refers to a cybernetic organism, which characterizes the chimera of a living organism and a machine. Owing to the widespread application of intracorporeal medical devices, cyborgs are no longer exclusively a subject of science fiction novels, but technically they already exist in our society. In this review, we briefly summarize the development of modern prosthetics and the evolution of brain–machine interfaces, and discuss the latest technical developments of implantable devices, in particular, biocompatible integrated electronics and microfluidics used for communication and control of living organisms. Recent examples of animal cyborgs and their relevance to fundamental and applied biomedical research and bioethics in this novel and exciting field at the crossroads of chemistry, biomedicine, and the engineering sciences are presented.     

Electrospun ceramic fibers: Composition, structure and the fate of precursors

Fibers are electrospun from aluminum acetate/polymer mixtures and characterized by an array of techniques before and after annealing at 1200 °C. We demonstrate that sodium and boron present in the initial starting materials as adducts and stabilizers remain incorporated into the resulting fibers after annealing and pyrolysis of the host polymer. The influence of these minor constituents on the surfaces of the fibers is suggested by infrared and X-ray photoelectron spectroscopic data. The presence of these species may impact potential chemical applications of small diameter ceramic fibers, such as their use as catalytic supports or for chemical decomposition.     

Reactions of trimethylsilyl fluorosulfonyldifluoroacetate with purine and pyrimidine nucleosides

Difluorocarbene, generated from trimethylsilyl fluorosulfonyldifluoroacetate (TFDA), reacts with the uridine and adenosine substrates preferentially at the enolizable amide moiety of the uracil ring and the 6-amino group of the purine ring. 2′,3′-Di-O-benzoyl-3′-deoxy-3′-methyleneuridine reacts with TFDA to produce 4-O-difluoromethyl product derived from an insertion of difluorocarbene into the 4-hydroxyl group of the enolizable uracil ring. Reaction of the difluorocarbene with the adenosine substrates having the unprotected 6-amino group in the purine ring produced the 6-N-difluoromethyl derivative, while reaction with 6-N-benzoyl protected adenosine analogues gave the difluoromethyl ether product derived from the insertion of difluorocarbene into the enol form of the 6-benzamido group. Treatment of the 6-N-phthaloyl protected adenosine analogues with TFDA resulted in the unexpected one-pot conversion of the imidazole ring of the purine into the corresponding N-difluoromethylthiourea derivatives. Treatment of the suitably protected pyrimidine and purine nucleosides bearing an exomethylene group at carbons 2′, 3′ or 4′ of the sugar rings with TFDA afforded the corresponding spirodifluorocyclopropyl analogues but in low yields.