Collective mechanism for nuclear stopping and transverse flow in heavy-ion collisions

The role of filamentation instability of quark-gluon plasma, in explaining collective phenomena in relativistic heavy-ion collisions, has been analyzed. Using equations of SU(2) two fluid color hydrodynamics it is shown that this instability can significantly enhance nuclear stopping and might contribute to collective sideward flows.     

Identification of metabolites of halofantrine, a new candidate anti-malarial drug, by gas chromatography-mass spectrometry.

Two previously unknown metabolites of halofantrine, a candidate anti-malarial drug, have been isolated by thin-layer chromatography from the plasma of dogs administered a single oral dose of 60 mg/kg. Their identifies were investigated after trimethylsilylation by gas chromatography-mass spectrometry under electron-impact and negative-ion chemical ionization conditions. The structural assignment was further confirmed by using a combination of elemental composition analysis of all the isotope peaks at low mass resolution and isotope pattern matching. These two metabolites were formed by modification of the dibutylaminopropyl side-chain of the parent compound involving deamination and oxidation or reduction.     

Time-resolved EPR studies on magnetic interactions between excited triplet (tetraphenylporphinato) zinc and doublet nitroxide radical

By time-resolved electron paramagnetic resonance (TREPR), four (tetraphenylporphinato) zinc (ZnTPP) complexes coordinated by an axial ligand containing a nitroxide radical (NRX; X=4, 5, 8, and 10, denotes the bond number from zinc to nitroxide nitrogen) have been studied in terms of magnetic interactions between the photoexcited triplet state of ZnTPP and NRX. The TREPR spectrum of ZnTPP coordinated by NR10 is almost the same as the one of ZnTPP coordinated by pyridine, indicating that the electron exchange interaction,J, between ZnTPP and the doublet nitroxide is negligibly small. On the other hand, TREPR spectra of the NR4 and NR5 complexes are assigned to the Q₁ state constituted by the ZnTPP and the nitroxide radical. In the case of the ZnTPP-NR8 complex, both T₁ and Q₁ TREPR signals are seen, which may originate from two conformations or degenerate T₁ states of ZnTPP. This EPR study is useful for understanding the photophysical and photochemical properties of chromophores.     

Enantiospecific synthesis of isomers of AES, a new environmentally friendly chelating agent

Three four-step enantiospecific syntheses of different diastereomers of AES, a new biodegradable chelating agent, are described. The stereocenters in each of the isomers are accessible from l- and d-malic and aspartic acids.     

Eine neue Methode zur Bestimmung der Thonerde

Ohne ZusammenfassungSt. Petersburg, den 20. April 1885.     

Mother-to-child transmission of HIV: a simulation-based approach for the evaluation of intervention strategies

Mother-to-child transmission (MTCT) of HIV is the most significant source of HIV infection in children below the age of 15 years. In 2000 alone, about 600 000 new infections occurred, the vast majority from mothers living in developing countries who were not aware of their HIV-positive status. To date, at least 4.3 million children have died from AIDS. In this paper, we discuss the development of an operational model that can be used to evaluate intervention options for the prevention of MTCT of HIV. The problem was approached by defining suitable pregnancy risk groups, prevention options and the required model outputs to evaluate different intervention strategies. The method chosen to approach the problem was a discrete-event, three-phase simulation, built in Visual Basic, with a stochastic semi-Markov structure. The developed model takes individual pregnant women through each stage of their pregnancy, labour and birth. Different intervention strategies may be modelled at any time, including short-course antiretroviral drugs and cessation of breastfeeding. The model is demonstrated with data from Botswana, which has one of the highest HIV-infection rates in the world.