Preparation of a Zinc Monocysteine Compound

Both zinc and the amino acid cysteine play important roles in biological function, including antioxidant protection and tissue repair. We attempted to prepare a (1:l) zinc‐cysteine complex using L‐cysteine and zinc metal. Zinc metal was added to a solution of L‐cysteine and refluxed with constant stirring. The product was selected by filtration and, after evaporation precipitation, was subjected to elemental analysis, ¹H NMR, and mass spectroscopy. The novel compound has one molecule of zinc conjugated to one molecule of cysteine.     

Molecular-orientation analysis based on alignment-induced TROSY chemical shift changes

We present a new NMR technique for determining the alignment tensor of a weakly aligned protein using only alignment-induced ¹⁵N transverse relaxation optimized spectroscopy (TROSY) chemical shift changes. Alignment-induced TROSY chemical shift changes reflect the combined contributions from two different anisotropic spin interactions including the residual dipolar couplings (RDCs) and the residual chemical shift anisotropy effects (RCSAs). We show here that these two residual anisotropic spin interactions’ values, encoded in the TROSY chemical shift changes, can be used to determine a weakly aligned protein’s alignment tensor. To prove the significance of this method, we show that our TROSY-based analysis gives the consistent alignment angles with those determined using RDCs for ¹⁵N-labeled ubiquitin (8.6 kDa) in an aligned medium, within an uncertainty range estimated by considering experimental and structural noises, being 5° at most. Because our approach requires a pre-determined ¹⁵N CSA tensor value, we also estimated the uncertainties associated with the resultant alignment tensor values caused by variation in ¹⁵N CSA tensors. In spite of the significant variations in literature-reported ¹⁵N CSA tensors, they gave consistent orientation angles within an uncertainty range. These results ensure that our TROSY-based approach is a useful alternative to the RDC-based method to determine the alignment angles especially for large proteins in a weakly aligned state.     

Non-destructive analysis of museum objects by fibre-optic Raman spectroscopy

Raman spectroscopy is a versatile technique that has frequently been applied for the investigation of art objects. By using mobile Raman instrumentation it is possible to investigate the artworks without the need for sampling. This work evaluates the use of a dedicated mobile spectrometer for the investigation of a range of museum objects in museums in Scotland, including antique Egyptian sarcophagi, a panel painting, painted surfaces on paper and textile, and the painted lid and soundboard of an early keyboard instrument. The investigations of these artefacts illustrate some analytical challenges that arise when analysing museum objects, including fluorescing varnish layers, ambient sunlight, large dimensions of artefacts and the need to handle fragile objects with care. Analysis of the musical instrument (the Mar virginals) was undertaken in the exhibition gallery, while on display, which meant that interaction with the public and health and safety issues had to be taken into account. Experimental set-up for the non-destructive Raman spectroscopic investigation of a textile banner in the National Museums of Scotland     

High temperature study of yttrium--barium--copper oxides near the YBa2Cu3Ox composition by 111In/Cd time differential \gamma--\gamma perturbed angular correlation spectroscopy

The local atomic order around very dilute indium impurities in c-axis-oriented YBa₂Cu₃O₇ and YBa₂Cu₃O_6.25 films at room temperature and in YBa₂Cu₃O_x bulk powders held in air or oxygen over a wide temperature range were investigated using ¹¹¹In/Cd \gamma--\gamma perturbed angular correlation (PAC) spectroscopy. The probe atoms occupy a single substitutional lattice position in YBa₂Cu₃O_x, and evidence reported here strongly supports previous claims that this is the yttrium position. In YBa₂Cu₃O_x powders, the local atomic order changes continuously with temperature. At room temperature the electric field gradient measured by PAC in bulk YBa₂Cu₃O_x powder is indistinguishable from that in the fully oxygenated YBa₂Cu₃O₇ film. Near the decomposition temperature, the bulk YBa₂Cu₃O_x powder data are semiquantitatively similar to data in the room temperature YBa₂Cu₃O_6.25 film, with quantitative differences that we attribute to temperature averaging in the former. Other sites usually found in PAC spectra of YBa₂Cu₃O_x bulk samples arise from ¹¹¹In dissolved in Y₂BaCuO₅ and Y₂Cu₂O₅ impurity phases. The latter phase apparently arises because of significant barium loss during processing; the barium deficiency is clearly demonstrated by comparison of PAC data with the alloy phase diagram above the decomposition temperature. PAC data on pure Y₂Cu₂O₅ are reported here also. This revised version was published online in July 2006 with corrections to the Cover Date.     

Multispecies Virial Expansions

We study the virial expansion of mixtures of countably many different types of particles. The main tool is the Lagrange–Good inversion formula, which has other applications such as counting coloured trees or studying probability generating functions in multi-type branching processes. We prove that the virial expansion converges absolutely in a domain of small densities. In addition, we establish that the virial coefficients can be expressed in terms of two-connected graphs.     

On a Conjecture of Finotti

We prove a conjecture of Luis Finotti about cubic polynomials of one variable in characteristic p. He checked it by computer for primes p < 890 and uses it to define and study the minimal degree lift of the generic point of an ordinary elliptic curve in characteristic p to the canonical lift mod p ³ of the curve. Received: 5 June 2002     

Phase-locking of a second-harmonic gyrotron oscillator using aquasi-optical circulator to separate injection and output signals

Phase-locking in a 34.5-GHz special complex cavity gyrotron oscillator operating at the second harmonic of the electron cyclotron frequency was studied. Injection of the locking power was made via a quasi-optical circulator connected to the gyrotron output. Locking bandwidth was measured by comparing the phase of the injection signal and output signal using a balanced mixer. Locking was observed with input power level as low as 40 dB below the gyrotron output power. The locking bandwidth is, however, narrower than in gyrotrons operating at the fundamental cyclotron frequency which may be attributed to the longer resonant cavity in the second harmonic gyrotron and the corresponding larger value of external quality factor. The measurements are roughly in agreement with predictions of Adler's phase-locking equation which is given for our system in terms of powers propagating in the output waveguide toward and away from the gyrotron cavity