Role of spin noise in the detection of nanoscale ensembles of nuclear spins

When probing nuclear spins in materials on the nanometer scale, random fluctuations of the spin polarization will exceed the mean Boltzmann polarization for sample volumes below about (100 nm){3}. In this Letter, we use magnetic resonance force microscopy to observe nuclear spin fluctuations in real time. We show how reproducible measurements of the polarization variance can be obtained by controlling the spin correlation time and rapidly sampling a large number of independent spin configurations. This allows significant improvement in the signal-to-noise ratio for nanometer-scale magnetic resonance imaging.     

Supersymmetric regulators and supercurrent anomalies

The supercurrent anomalies of the supercurrent $\text{S}$_μ of the supersymmetric Yang-Mills theory in Wess-Zumino gauge are computed using the supersymmetric dimensional regulator of Siegel. It is shown that $\text{γ}{}_{\mathrm{\mu }}\text{S}{}^{\mathrm{\mu }}\text{=0}$ and $\text{?}{}_{\mathrm{\mu }}\text{S}{}^{\mathrm{\mu }}\text{≠0}$ in agreement with an earlier calculation based on the Adler-Rosenberg method. The problem of exhibiting the chiral anomaly and a regulator for local supersymmetry suggests that the interpretation of dimensional reduction in component language is incomplete.     

Copper and iron interactions with angiotensin-converting enzyme inhibitors. A study by fast-atom bombardment tandem mass spectrometry

Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd.     

Two‐dimensional non‐close‐packed arrays of nanoparticles via core‐shell nanospheres and reactive ion etching

Nanosized PTFE/polystyrene core‐shell particles were prepared by seed emulsion polymerization technique starting from PTFE seeds of 20 nm. At the end of the reaction, no residual PTFE nor secondary nucleation was observed and by appropriately choosing the ratio between the monomer and the PTFE seed it was possible to obtain particles, with predetermined size in the range 60–100 nm, featuring an extremely narrow size distribution. These particles were successfully employed as building blocks for the preparation of large scale nanosized monolayers through the floating technique. Reactive ion etching was further applied to modulate the size characteristics of the resulting 2D ordered nanostructure. Although for relatively short RIE times a peculiar continuous morphology was observed in which the particles are interconnected through thin arms, on further increasing the RIE time a well‐organized 2D arrangement of particles with size of about 30 nm was obtained. Considering the shell as an expendable ordering and spacing tool, the use of core‐shell nanospheres allows a wide variety of controlled morphologies to be designed and prepared thus opening new perspectives for nanostructure fabrication processes through nanosphere lithography (NSL). Copyright © 2011 John Wiley & Sons, Ltd.     

On the renormalization method: a different outlook,and the energy-momentum tensor in the gφ4 theory

An alternate method of renormalizing a quartic self-interacting boson theory has been developed. We find that one can obtain finite renormalized expressions for the perturbation theory contributions to the Green's function without carrying out limiting procedures. As a consequence of the analysis, one is able to renormalize explicitly the field energy-momentum tensor to all orders. There exists a one-parameter family of renormalized tensors. The method will allow for a simple determination of the asymptotic “zero-mass” theory.