The harmonic approximation for the potential energy of proteins is known to be inadequate for the calculation of many protein properties. To study the effect of anharmonic terms on protein vibrations, the anharmonic wave functions for the ground state and low-lying excited states of the bovine pancreatic trypsin inhibitor (BPTI) were calculated. The results suggest that anharmonic treatments are essential for protein vibrational spectroscopy. The calculation uses the Vibrational self-consistent field approximation, which includes anharmonicity and interaction among modes in a mean-field sense. Properties obtained include the quantum coordinate fluctuations, zero-point energies, and the vibrational absorption spectrum.
The new pharmaceutical and diagnostic compns. comprise antibody-aggregates and hydrophobic drug or marker mols. The drug or marker mols. are solubilized inside micelle-like antibody-aggregates. In a process for prepg. such types of compns., hydrophobic residues are attached to the antibodies in the presence of a surface active agent. After removal of this agent the hydrophobic drug or marker mols. are solubilized inside the resulting antibody aggregates. A method for targeting mols. towards specific cells and sites within a living body is also disclosed. [on SciFinder(R)]
Air is shown to burn (in theory, using two complementary procedures) under the unusual combination of conditions made possible within a cluster heated by a supersonic impact at an inert surface. Both clusters of neat N-2/O-2 and clusters containing several N-2 and O-2 molecules within a rare gas envelope have been studied. The principal reaction is N-2+ O-2 –> 2NO which proceeds via a four-center mechanism. The four-center reaction N-2 + O-2 –> N2O + O leads to N2O which is quite hot, as is to be expected on the basis of kinematic considerations, and is efficiently destroyed as the cluster expands. During the early, compression, stage multi- (>4) center reactions readily occur. The results of molecular dynamics simulations using a many-body potential are well accounted for by a distribution of products of maximum entropy subject to conservation of energy, matter and charge.
This paper is a study of French Calvinism as a language. It was a language which employed the signifiers and the signs of the traditional Christian culture. There was persistent usages of key Catholic words in the theology of early Huguenot believers, regardless of their level of education or commitment to the cause. In an attempt to follow one such word ("miracle": miracula or mirabilia), a large number of texts are examined, including Calvin's own writings, the Histoire ecclésiastique, Simon Goulart's Mémoires de l'estat de France sous Charles Neufiesme, and the personal diary of an anonymous believer in the provincial town of Millau.
We consider the possibility of smectic and columnar phases in fluids and colloidal suspensions of aligned rods and disks interacting through excluded-volume forces. After briefly reviewing previous work, and applying known cell model techniques to compare the phase behaviors of disks and rods, we present and discuss the results from new Monte Carlo simulations of perfectly oriented rods (spherocylinders) and disks (torocylinders). We conclude tentatively that columnar phases are stable only in the case of disks.
Nechama Muskal, Iva Turyan, Avital Shurky, and Daniel. Mandler. 1995. “Chiral Self-Assembled Monolayers..” J. Am. Chem. Soc.Journal of the American Chemical Society, 117, 3, Pp. 1147 - 8. Abstract
The organization of chiral self-assembled monolayers (SAMs) composed of a thiol deriv. of phenylalanine on a hanging mercury drop electrode (HMDE) has been studied. Comparing the excess of surface coverage of homo and heterochiral monolayers reveals that the latter are more densely packed. This was also supported by examn. the differential capacitance and the electrochem. behavior of an outer-sphere redox couple at surfaces covered by homochiral monolayers vs. monolayers based on the racemic mixt. [on SciFinder(R)]
The implementations of classical and quantum molecular dynamics simulations on distributed-memory massively parallel computers are presented. First, we discuss the implementation of large-scale classical molecular dynamics (MD) simulations on SIMD architecture parallel computers, and in particular, on the family of MasPar distributed-memory data parallel computers. We describe methods of mapping the problem onto the Processing Elements (PE's) of the SIMD architecture, and assess the performance of each strategy. The detailed implementations of this data parallel construct are illustrated for two case studies: classical MD simulation of a two-dimensional lattice and the photodissociation mechanisms of a diatomic iodine impurity in a three-dimensional argon lattice. We also present a study of quantum dynamics using the Time-Dependent Self-Consistent Field (TDSCF) method. These calculations demonstrate the potential of using massively parallel computers in MD simulations of thermodynamic properties and chemical reaction dynamics in condensed phases.
A spectrum of final states can be produced in many ways; It can be a bound-bound process as in optical spectroscopy, a bound-continuum process as in photodissociation, or even a continuum-continuum transition as in a scattering experiment. A homogeneously broadened, resolved, spectrum exhibits variations in intensity which, while fully predictable by quantum dynamics, appear to the eye as `'fluctuations''. A phase space structure in which the statistical properties of such fluctuations can be examined is defined and discussed. In the classical limit, one recovers the results of `'surprisal analysis''. In the more general case, one obtains an extension to situations where quantal interference effects can be important.
The migration-inducing effect of an institution of higher education is often overlooked in university impact studies. This paper deals with estimating the local economic impacts of a university accounting for the fact that students and staff induced to the area by the presence of the university are unlikely to remain in its absence. It is argued that this is an important aspect of the correct identification of the counterfactual position and a vital component in accurate impact analysis. A case study is presented relating to the short-term impacts of the Northwestern University campus in the city of Evanston, Illinois. The tendency to overstate this impact through the incorrect treatment of induced migration is illustrated. It is also shown that the estimated income and output impacts attributed to the university are very sensitive to changes in the local consumption patterns of migrants.
This work focuses on code design and code selection rules under power and decoding delay constraints for an antipodal (BPSK) modulated and convolutionally encoded communication system. The system operates over a slowly fading AWGN channel, described here by the block-fading model. We specialize to perfect coherent detection with maximum likelihood decoding assuming ideal channel information (the instantaneous fading values). The dominant design criterion in this scenario is the code diversity level in terms of blocks while the standard Hamming distance plays a secondary role. A code design procedure, based on maximum distance separable (MDS) cyclic block codes is presented along with a code-search algorithm. The performance results of selected codes are assessed via simulation and compared to those achieved by Reed-Solomon codes with erasure and error decoding.
A highly specific and sensitive electrode for the detn. of ultra-low levels of Hg and an anal. system based on such electrode are described. The electrode is a glassy C electrode spin-coated with a monolayer of a highly sensitive reagent for the detection of Hg. The anal. method based on the use of this type of electrode is a voltammetric method. Concns. of the order of as low as ∼2 × 10-12 Mol Hg can be detected and measured. The reagent is 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo-[8.8.8]hexacosane. [on SciFinder(R)]
