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1.
Michael P. Hartshorn Richard G. Jensen A. Grant Waller Graeme J. Wright 《Tetrahedron letters》1987,28(52):6701-6704
Reaction of the 15N-4-nitrodienone (1) with excess nitrogen dioxide in benzene for 16 h gives the 4,5,6-trinitro ketone (2), labelled (15NO2) at C6 but not at C4, and recovered 4-nitrodienone (1) in which extensive loss of 15NO2 has occurred. The mechanistic implications of these and related results are discussed. 相似文献
2.
Mark P. Waller Thomas Dresselhaus Jack Yang 《Journal of computational chemistry》2013,34(16):1420-1428
Here, we present just a collection of beans (JACOB): an integrated batch‐based framework designed for the rapid development of computational chemistry applications. The framework expedites developer productivity by handling the generic infrastructure tier, and can be easily extended by user‐specific scientific code. Paradigms from enterprise software engineering were rigorously applied to create a scalable, testable, secure, and robust framework. A centralized web application is used to configure and control the operation of the framework. The application‐programming interface provides a set of generic tools for processing large‐scale noninteractive jobs (e.g., systematic studies), or for coordinating systems integration (e.g., complex workflows). The code for the JACOB framework is open sourced and is available at: www.wallerlab.org/jacob . © 2013 Wiley Periodicals, Inc. 相似文献
3.
Mass spectral analysis of carbohydrates has become an important tool for the biological chemist1–3 and the use of mass spectrometers interfaced with gas-liquid chromatographs has provided a convenient method of study for volatile derivatives of carbohydrates. Several groups4–7 have accomplished separations of the various isomeric trimethylsilyl (TMSi) esters and ethers of the glucuronic acids. The present work utilizes a gas-liquid chromatograph-mass spectrometer to examine the previously unreported mass spectra of pertrimethylsilylated glucuronic acids and these spectra are compared to the previously reported8 spectra of the pemethylated glucuronic acids. 相似文献
4.
Waller MP Howard ST Platts JA Piltz RO Willock DJ Hibbs DE 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(29):7603-7614
The charge distribution of taurine (2-aminoethane-sulfonic acid) is revisited by using an orbital-based method that describes the density in a fixed molecular orbital basis with variable orbital occupation numbers. A new neutron data set is also employed to explore whether this improves the deconvolution of thermal motion and charge density. A range of molecular properties that are novel for experimentally determined charge densities are computed, including Weinhold population analysis, Mayer bond orders, and local kinetic energy densities, in addition to charge topological analysis and quantum theory of atoms-in-molecules (QTAIM) integrated properties. The ease with which a distributed multipole analysis can be performed on the fitted density matrix makes it straightforward to compute molecular moments, the lattice energy, and the electrostatic interaction energies of molecules removed from the crystal. Results are compared with high-level (QCISD) gas-phase calculations and band structure calculations employing density functional theory. Finally, the avenues available for extending the range of molecular properties that can be calculated from experimental charge densities still further using this approach are discussed. 相似文献
5.
The metal content of a series of contaminated sediments has been determined by equilibrating ion-exchange resins of different types (held in porous cages) with aqueous suspensions of the sediments. H(+)-form exchangers took up high proportions of the Cu, Pb, Zn and Cd contents with recoveries depending on whether the acid functional groups were strong. Na(+)-form exchangers took up a smaller, loosely bound, labile fraction. The metal ions held on the exchangers were back-extracted into 0.05M EDTA and determined by flame AAS. Dissolution of sediment components led to the exchangers also taking up large amounts of Ca, Mg, Fe and Al. The exchange-resin technique provides an alternative means of subdividing the metal content of sediments into different "labile" or "available" fractions. Possible advantages include minimal re-adsorption of released metal ions by the sediment phases, retention of only "labile" species (ions or complexes), and a transfer mechanism which may resemble the action of plant roots more closely than chemical extractant processes do. 相似文献
6.
7.
Degradative and other data described below have shown that the tannin of unripe fruits of persimmon (Diospyros virginiana) actually contains (+)-gallocatechin unit in the structure and must be regarded as condensed flavonoid pigments, probably of similar structure to the polymeric proanthocyanidin from avocado seed. The possible structure of the proanthocyanidin from persimmon fruits is proposed tentatively as a polymer of 5, 7, 3′, 4′, 5′-pentahydroxyflavanonol. 相似文献
8.
John?Bartley Thomas?Soltau Hereward?Wimborne Sunjun?Kim Angeline?Martin-Studdard David?Hess William?Hill Jennifer?Waller James?CarrollEmail author 《BMC neuroscience》2005,6(1):15
Background
Mechanisms that affect recovery from fetal and neonatal hypoxic-ischemic (H-I) brain injury have not been fully elucidated. The incidence of intrapartum asphyxia is approximately 2.5%, but the occurrence of adverse clinical outcome is much lower. One of the factors which may account for this relatively good outcome is the process of neurogenesis, which has been described in adult animals. We used a neonatal mouse model to assess new cells in the hippocampus after H-I injury. 相似文献9.
10.
W. S. Andrews E. J. Waller P. Brousseau G. Roy X. Cao K. A. M. Creber L. S. Erhardt 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(3):919-922
During the past decade, interest has increased in qualifying and quantifying the threat posed to the public by the illegal
use of radionuclides. In order to take investigations beyond the laboratory bench into more realistic scenarios, environmental
and safety considerations dictate that these studies be performed on stable and benign surrogates. This paper discusses some
of these studies, specifically the use of cerium dioxide for actinide ceramics and calcium and natural strontium ceramics
for those based on 90Sr. 相似文献