On-Line LC-GC for the Analysis of the Minor Components in Edible Oils and Fats – The Direct Method Involving Silylation

The previous on-line LC-GC method for the direct analysis of the minor components in oils and fats (without cleavage of esters) was modified: The free alcohols/sterols were silylated instead of acylated, and the LC fraction transferred to GC is widened to range from the beginning of the LC chromatogram up to the sterol esters. Silylation eliminated the problem that acylation may esterify some free alcohols with free fatty acids from the oil if the oil or fat is of high acidity. Widening of the LC fraction to include squalene and the tocopherols added information to that previously obtained.     

Stereochemistry and Circular Dichroism of Chiral Internal Olefin-Platinum(II) Complexes

A series of cis- and trans-dichloro(benzylamine) (chiral olefin) platinum(II) complexes, containing (Z) and (E) isomers of the internal chiral olefins R-CH=CH-R', has been prepared by ethylene displacement from the corresponding ethylene containing complexes. The particular stereochemical features of the complexes allow one to interpret the CD on the basis of the individual contributions coming from the chiral centres already present in the free olefin and from the chiral centres formed in the complexation of the double bond. Evidence is reported showing that the aforementioned contributions are additive and that the chiral centre(s) bound to the metal dominates the CD at about 400 nm, its chirality type being reflected in the sign and its chirality prevalence in the Δϵ value.     

Vacuum-u.v. circular dichroism of optically active isotactic poly-α-olefins

Summary Circular dichroism of isotactic samples of poly-(S)-4-methyl-1-hexene and poly-(R)-3,7-dimethyl-1-octene, have been measured in the vacuum ultraviolet spectral region (200-140 nm). The c.d. band at about 160. nm accounts for the optical activity in the visible region and reflects the presence of one screw sense helical conformation of the sample examined.The authors thank Prof. W.C. Johnson, Jr., Department of Biochemistry and Biophysics, Oregon State University, for allowing them to use the vacuum u.v. spectrometer. This work has been partially supported by a N.A.T.O. grant, and by Ministero Pubblica Istruzione (MPI), Roma — Italy.     

Molecular and technological characterization of Staphylococcus xylosus isolated from naturally fermented Italian sausages by RAPD, Rep-PCR and Sau-PCR analysis

Coagulase-negative cocci (CNC) are important microorganisms in fermented sausages because they release lipases and proteases that are able to free short-chain fatty acids and peptides and aminoacids, respectively, that are responsible for the aroma of fermented sausage. The purpose of this study was to characterize Staphylococcus xylosus strains isolated from naturally fermented sausages, produced in three different processing plants in the Friuli Venezia Giulia region in the Northeast of Italy. Two hundred and forty-nine strains of S. xylosus were identified by species-specific PCR and subjected to molecular and technological characterization. RAPD-PCR with primer M13, Rep-PCR using primer (GTG)(5) and Sau-PCR with primer SAG(1) were used for the molecular analysis, while the capability of the strains to grow at different temperatures and in the presence of NaCl and their lipolytic and proteolytic activity were tested in order to define the technological characteristics. The results obtained allowed us to differentiate strains coming from different plants, thereby admitting the presence of strains that are plant-specific.     

Crystallisation of high density polyethylene from dilute solution: Heterogeneous nucleation

The self-seeding crystallisation technique is applied to a dilute solution of polyethylene in xylene containing, in suspension, foreign particles; data concerning some pigments usually employed for colouring the plastics are reported. It is shown that this method allows easy demonstration of the interactions existing between the dissolved polymer and the pigment; at the same time, it is possible to study the morphology which is evolved as a consequence of these interactions under particularly simple conditions as only a small amount of polymer crystallises on the pigment particles. The behaviour of several pigments is consistent with the results obtained by crystallising the bulk polyethylene coloured with the same pigments. Some unusual morphologies are made evident.     

Amnestic mild cognitive impairment: Difference of memory profile in subjects who converted or did not convert to Alzheimer's disease.

Episodic long-term, short-term, and implicit memory were investigated in 79 elderly subjects who fulfilled criteria for the amnestic form of mild cognitive impairment (a-MCI; i.e., by having an idiopathic amnestic disorder with absence of impairment in cognitive areas other than memory and without confounding medical or psychiatric conditions) and who developed Alzheimer's disease (AD) after 2 years as well as in 111 subjects affected by a-MCI who did not develop dementia. Results document a memory profile in a-MCI subjects characterized by preserved short-term and implicit memory and extensive impairment of episodic long-term memory. In virtually all episodic memory indexes examined (learning, forgetting, recognition abilities), a-MCI subjects who converted to AD were more severely impaired than were subjects who did not become demented. This memory profile, which closely resembles that exhibited by amnestic patients with bilateral mesial-temporal lobe lesions, confirms a precocious phase in preclinical AD characterized by selective involvement of mesial-temporal areas and worsening of the memory impairment as atrophic changes progress in hippocampal structures. In this context of pervasive episodic memory impairment, tests assessing the free recall of verbal material following a delay interval demonstrated the greater sensitivity to memory deficits of a-MCI subjects who developed AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quasiparticle correction for electronic transport in molecular wires

In this paper we present calculations of ballistic transport in molecular wires. The calculations are performed using an approximated version of the GW correction in the plasmon-pole framework, which is used to improve the starting Density Functional Theory energy spectrum of the molecule between metallic leads. We show that this correction reduces the error of the correlation part for the electron energy. Finally a model with complex bands is implemented in order to get the damping regime for long polymers.