On the confluent singularity for bond-weighted undirected animals

Analyses of the expansions for bond weighted undirected site animals give support to an estimate range for the first confluent singularity overlapping with that for the total number of animals (in two dimensions).     

On the Crystal-to-Mesophase Phase Transition in Copper(II) Salts of Even-Chain Fatty Acids

The phase transition from the solid state to the liquid crystal state was investigated for the copper(II) salts of the fatty acids with 10, 12, 14, 16 or 18 carbon atoms in the chain, by measuring the temperature dependence of the conductance and capacitance of a cell containing the material under investigation. The temperatures deduced from these dependences agree reasonably with those found by DSC measurements and with those to be found in the literature. Differences in dielectric behaviour between the samples are qualitatively discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Dispersion theory of multiple-prism beam expanders for pulsed dye lasers

The single pass dispersion of multiple-prism beam expanders of interest for practical pulsed dye laser cavities is calculated. The theory is extended to enable evaluation of the overall (outward and return pass) dispersion of multiple-prism-grating combinations. It is found that although the contribution to overall dispersion from the prisms can be minimized (though not eliminated for practical expanders) by arrangement of the prisms in compensating pairs, it is in any case small (≈2%) compared to the contribution to dispersion from the grating in practical cavities. Formulae for dispersion of multiple-prism-grating combinations including up to four prisms arranged in additive or compensating configurations are given; the dispersion of an arbitrary number of prisms arranged in conjunction with a grating can also be calculated. The implications for output linewidth of pulsed dye lasers incorporating prism beam expanders are discussed.     

Treatment of long‐term stored DNA—Comparison between different methods to obtain high‐quality material

Long‐term stored DNA can be sometimes the only source of genetic material of an organism that does not exist anymore, but a research interest still persists. However, there is a lack of information about useful methods to improve quality from such type of material. In this study, we compared four different protocols using DNA samples collected in 1998. Fresh DNA was also tested aiming to check the differences between these two material types. Sixteen samples of each DNA type treated with phenol‐chloroform with PEG 5.0%, silica‐gel membrane spin column, PEG 7.5%, and glass‐fiber matrix spin column were submitted to spectrophotometer measurements, electrophoresis, PCR, and RFLP‐PCR to assess the best method concerning yield, quality, and purity. Based on the results, purification with PEG 7.5% was considered the best method to treat aged DNA samples. In addition to the efficiency, this protocol has low cost. Analyzing the data, we also conclude that long‐term stored DNA may be considered a reliable and potential resource for future molecular studies.     

Analysis of salivary peptides using HPLC-electrospray mass spectrometry

Salivary peptides are involved in a wide range of functions constituting the first line of defence of oral cavity and precursors of dental pellicle formation. The presence of mucins in saliva makes difficult the analysis of the proteic content. This is due mainly to aggregation phenomenon between mucins and other high molecular weight glycoproteins and salivary proteins. Considering the importance of salivary peptides in biological functions, we have evaluated the influence of four different extraction methodologies on the separation and identification of these proteins by HPLC-MS. Based on their molecular weight, we identified a total of 22 peptides when extraction was performed using a solution of guanidine (6 m), compared with 14 peptides identified when saliva is acidified with TFA, which is an often used procedure. Our results also show the presence of mucin bind peptides, which include statherin, PRP1, PRP3, Histatin 1 and Histatin 5.     

Directed-site percolation clusters: The scaling function in dimensions two to six

Exact series for lattices of dimension between 2 and 6 are used to report on the asymptotic features of the scaling function for the average number of clusters in directed percolation, close to, and away from, the most recent estimated intervals forp _c . Scanning of the noncritical regions yields exponent ranges compatible with the undirected percolation equivalents. Close top _c the scaling function varies fairly linearly in terms of the variablez=(p–p _c )s and this result is rather stable particularly bearing in mind the modestly available precision forp _c in higher dimensionalities.     

Collapse transition and cyclomatic number distribution of directed lattice animals

We computed the specific heat of directed lattice animals using a Monte Carlo method for various animals sizesN, withN up to 100 on the square andN up to 125 on the simple cubic lattices. The specific heat as a function of the temperature for various animal sizes exhibits peaks which seem to approach a collapse transition temperature monotonically from below with increasingN. A least square fit together with finite-size scaling then gives both the transition temperature T_c and the specific heat exponent for these two lattices. The cyclomatic number distributions for the number of animals with fixed animal sizeN are also calculated and these seem to obey a scaling law for largeN. On leave from Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China.