Analysis of Fluorescent Proteins with a Nanoparticle Probe

This letter presents the first application of high energy, single nanoparticle probes (e.g., 520 keV Au(400) 2nm NP) in the characterization of surfaces containing fluorescent proteins (e.g., GFP variants) by their co-emitted photon, electron and secondary ion signals. NP induced protein luminescence increases with the NP incident energy, is originated by the NP impact and is transferred to the protein fluorophor via electronic energy transfer. Multi-electron emission is observed per single NP impacts and their distributions are specific to the target morphology and composition. Fragment ions of protein sub-units consisting of 2-7 amino acid peptides are observed under individual NP impacts that can be correlated to the random protein orientation relative to the impact site (e.g., outer layer or "skin" of the protein).     

Continuous-wave tunnel ring fiber laser

The continuous-wave oscillation of a tunnel ring fiber laser is demonstrated. The high losses encountered in tunneling systems are compensated for by a high-gain amplifying medium from barrier widths for 0 to lambda/2. The experimental observations are in good agreement with a simple theoretical model. This near-field probe system allows one to detect small displacements in the picometer range.     

Kinetics of adsorption of polyvinylamine on cellulose fibers. II. Adsorption from electrolyte solutions

Adsorption from electrolyte solutions of fully hydrolyzed polyvinylamine on cellulose fibers was investigated by supplying the polymer to the fibers at controlled rate. This was implemented by employing a reactor only open to the fluid in which the fiber dispersion were confined and homogenized. The adsorbed layers may be defined as diffuse or dense layers. Diffuse layers are characterized by a surface coverage limited to 0.65 mg/g cellulose in salt-free solutions. Addition of NaCl or CaCl(2) to the fiber dispersion and the polymer solution promotes the adsorption rate and increases the amount of adsorption to 1.5 mg/g cellulose. For dense polymer layers, for which the coverage amounts to values close to 10 mg/g cellulose in salt-free systems, addition of electrolyte does not change the kinetic and adsorption characteristics. Insofar as the variation of the molecular areas of the polymer within the diffuse layers as a function of the ionic strength parallels the variation of the molecular characteristics of solute molecules, the formation of diffuse layers is expected to proceed by random deposition of solute molecules which later individually sustain strong reconformation. Adsorption isotherms show a limited influence of the ionic strength. Obviously, the passage from dense layers of high surface coverage to low adsorption values at equilibrium requires extended reconformation of adsorbed macromolecules and desorption of a great part of the molecules already adsorbed.     

Optimization of the separation of polymethoxylated flavones in reversed phase liquid chromatography

Summary An optimization procedure for the chromatographic separation of polymethoxylated flavones is described. A polyhedron working volume is drawn from a truncated tetrahedron constructed from the four solvents selected. The response function is an n'th degree polynomial the coefficients of which are calculated through the least squares method by means of B=(XX)^–1XY in which XX is the information matrix (XX)^–1 the variance covariance matrix. X is the matrix of the model (polynomial built from the selected experiments) and X the transposed matrix. Y is the quality of the chromatogram defined by the resolution of each pair of solutes. An exchange algorithm matrix yields the minimum number of runs necessary to obtain a correct B. Isoresponses curves are drawn by intersection of a cubic volume which includes the polyhedron to give a better insight. An optimal zone is then determined and provides the solvent composition. An optimized chromatogram of 8 methoxylated flavones demonstrates the application of the method.     

Relation between classical and quantum mechanics

Expressions for the Lie derivatives of functions of non-commuting variables are derived and used to reformulate classical mechanics. This is possible only if the phase space variables commute, or if they satisfy Heisenberg's commutation relations.This work was supported in part by the National Science Foundation Grant Number NSF GP-14803, and by the Air Force Office of Scientific Research, contract number AFOSR 68-1524.     

A new route to 7-deazaguanine derivatives

The Synthesis of 2-amino-4,6-dichloro-5-(2,2-diethoxyethyl) pyrimidine $\text{7}$ has been performed in four steps starting from guanidine and diethylallylmalonate. $\text{7}$ is a new key intermediate for the synthesis of 7-alkyl-2-amino-3,4-dihydro-7H-pyrrolo [2,3-d] pyrimidin-4-ones.     

The Electrochemical Measurement of Rate Constants for the Catalyzed Oxidation and Reduction of Water in microheterogeneous systems

The appearent first-order rate constants for the oxidation of water by iron tris (bipyridyl) (Fe (bpy)³⁺₃), and reduction of water by methylviologen (MV⁺) catalyzed by a stabilized RuO₂ or Pt-sol, respectively, were measured. Rate constants for water oxidation at pH 7 of 0.4 s^?1 and water reduction at pH 4.7 and pH 1 of up to 460 s^?1 for different sols were found.     

Über eine Fernfokus-Elektronenkanone und ihre Anwendungen

Ohne Zusammenfassung