High level investigations

A high level investigation will involve a team-based investigation, involving supervisors or line managers, health and safety advisers and employee representatives. It will be carried out under the... 

Baranowska et reported a high-level investigation of the potential energy surface (PES) of the Ne-CO interaction. The calculations were performed at the CCSD(T) level of theory with the d-aug-cc-pVTZ basis set supplemented with 3s3p2dlflg midbond functions. The minimum of the PES corresponds to a nearly T-shaped structure with the Ne atom located at a distance of 3.383 A from CO and an angle of 79.4°. The interaction-induced electric dipole moment and polarizability was determined at the CCSD/d-aug-cc-pVTZ-33211 level of theory. In addition, the authors determined the dielectric and refractivity virial coeflicients and the pressure virial coeflicients of the CO-Ne complex. 

The widespread usage of phthalates in flexible PVC has resulted in many investigations being made of their concentration in the environment. Unfortunately the ubiquitous presence of phthalates in laboratory chemicals and equipment has caused problems in the analysis of very low concentrations of phthalates in environmental samples and has led to erroneously high levels being reported. 

From this equation it is seen that parameters have been introduced into the QM-MM method, with K, L, M, and corresponding to the pseudo s orbital on the classical atom. These parameters can be optimized to reproduce experimental or high level theoretical data. Field et al. [9] perfonned extensive investigations of the values of these extra parameters and suggested that the parameters K, L, and M (i = 1,. . . , 4) can be set to zero and that should take a value of 5.0. These are generally the values used in most current QM-MM implementations that employ semiempirical methods in the quantum region. 

A quick scan of the collection of structures in Part Three will confirm the high level of activity and accomplishment which has been associated with the field of chemical synthesis over the past three decades. Upon closer inspection, it becomes apparent that the rate of achievement of successful syntheses has been increasing steadily with time. As of this writing (1988) there are many laboratories in which outstanding work on multistep synthesis of complex molecules is being carried out. One consequence of this intense effort is that the problem of keeping track of the literature of synthesis has become a difficult one for investigators and students. The... 

Studies of actinide photochemistry are always dominated by the reactions that photochemically reduce the uranyl, U(VI), species. Almost any UV-visible light will excite the uranyl species such that the long-lived, 10-lt seconds, excited-state species will react with most reductants, and the quantum yield for this reduction of UQ22+ to U02+ is very near unity (8). Because of the continued high level of interest in uranyl photochemistry and the similarities in the actinyl species, one wonders why aqueous plutonium photochemistry was not investigated earlier. 

Extensive quantum chemical calculations have been reported for sulfur-rich compounds in the past two decades. These calculations were used to investigate molecular structures and spectroscopic properties, as well as to understand the nature chemical bonding and reaction mechanism. Many high-level ab initio calculations were used for interpretation of experimental data and for providing accurate predictions of molecular structures and thermochemical data where no reliable experimental values are available. In recent years, density functional calculations have been extensively tested and used on many first- and second-row compounds. These proven DFT methods look promising for larger systems because for their computational efficiency. 

Immediate hypersensitivity reactions to RCM are associated with histamine release from basophils and mast cells [27], and extensive mast cell activation in vivo associated with clinical symptoms has been demonstrated by Earoche et al. [31]. Patients with hypersensitivity reactions after contrast medium exposure had increased plasma levels of both histamine and tryptase, and levels correlated with severity. Also other investigators have reported high levels of tryptase in connection with severe or fatal reactions [21, 33]. 

Second, there has been another severe outbreak of paralytic shellfish poisoning along the Pacific coast of Central America, with veiy high levels of shellHsh toxicity detected in Guatemala. There have, however, been no deaths and very few illnesses reported there, due to a timely response based on information gained from detailed investigations of the first outbreak. This time they were ready. 

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