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Dendroctonus jeffreyi andD. ponderosae are morphologically similar sympatric species of pine bark beetles over portions of their geographic ranges; however,D. jeffreyi is monophagous onP. jeffreyi whileD. ponderosae is highly polyphagous. Both species carry a species of mycangial fungi that are also very similar in appearance. Growth of the two mycangial fungi and of the fungusLeptographium terebrantis (associated with the polyphagous and non-tree-killingDendroctonus valens) in the presence of oleoresin constituents of host and nonhost conifers was tested by placing individual chemicals on agar growth medium and by growing the cultures in saturated atmospheres of the chemicals. The fungus associated withD. jeffreyi showed greater tolerance for chemical constituents placed on the growth medium than the other two fungi, and growth after three days was enhanced by heptane, the dominant constituent ofP. jeffreyi oleoresin. Growth of all three species of fungi was reduced by the resin constituents when the chemicals were presented as saturated atmospheres. The results suggest that the influence of the tree on growth of the symbiotic fungi of the bark beetles during the initial attack process may be different than after colonization by the beetles is complete. The difference in the responses of the apparently related species of mycangial fungi may provide some new insight into the evolutionary history of these beetle/mycangial fungus/host tree systems. 相似文献
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R. Bai C. L. Briant D. C. Paine J. R. Beresford 《Metallurgical and Materials Transactions A》1998,29(3):757-764
This article presents a study of the evolution of the annealing texture in hafnium, as measured by electron backscattering
diffraction patterns (EBSPs). It was found that the annealing texture of asreceived extruded rod depended on the annealing
temperature. After low-temperature recrystallization, the deformation axis was parallel to
or
and the basal planes were approximately parallel to the deformation axis. These orientations were deduced by the position
of the points in the standard stereographic triangle used to produce the inverse pole figure. As the annealing temperature
was raised to 1700 °C, the direction parallel to the rolling direction changed to
and the grain size increased. It appeared that the increase in grain size occurred by a process of abnormal grain growth,
and this abnormal grain growth appeared to be the cause of the change in the texture. Texture was also examined in samples
that had been warm rolled to thickness reductions between 10 and 90 pct and then annealed at 1700 °C. In these samples, the
main feature of the texture was that the basal plane became parallel to the rolling plane as the amount of rolling increased.
The maximum grain size was observed in samples that had been rolled to a reduction in thickness of 50 pct. 相似文献
4.
Paine SW Barton P Bird J Denton R Menochet K Smith A Tomkinson NP Chohan KK 《Journal of molecular graphics & modelling》2010,29(4):529-537
In silico models that predict the rate of human renal clearance for a diverse set of drugs, that exhibit both active secretion and net re-absorption, have been produced using three statistical approaches. Partial Least Squares (PLS) and Random Forests (RF) have been used to produce continuous models whereas Classification And Regression Trees (CART) has only been used for a classification model. The best models generated from either PLS or RF produce significant models that can predict acids/zwitterions, bases and neutrals with approximate average fold errors of 3, 3 and 4, respectively, for an independent test set that covers oral drug-like property space. These models contain additional information on top of any influence arising from plasma protein binding on the rate of renal clearance. Classification And Regression Trees (CART) has been used to generate a classification tree leading to a simple set of Renal Clearance Rules (RCR) that can be applied to man. The rules are influenced by lipophilicity and ion class and can correctly predict 60% of an independent test set. These percentages increase to 71% and 79% for drugs with renal clearances of < 0.1 ml/min/kg and > 1 ml/min/kg, respectively. As far as the authors are aware these are the first set of models to appear in the literature that predict the rate of human renal clearance and can be used to manipulate molecular properties leading to new drugs that are less likely to fail due to renal clearance. 相似文献
5.
In June 2010, the US Environmental Protection Agency (EPA) finalized a new, very stringent National Ambient Air Quality Standard (NAAQS) for sulfur dioxide1 (SO2). 相似文献
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Maomin Fan Eileen N. Duesler Jerzy F. Janik Robert T. Paine 《Journal of Inorganic and Organometallic Polymers and Materials》2007,17(2):423-437
The transamination reactions between Ti(NMe2)4 and 1,3,4,5,6-pentamethyl-2-aminoborazine, (Me)3N3(Me)2B3(NH2), and diphenylamine (Ph2NH) and between [Zr(NMe2)4]2 and 1,3,4,5,6-pentamethyl-2-aminoborazine, aniline (PhNH2) and diphenylamine have been studied and the molecular product species have been isolated, spectroscopically characterized
and single crystal X-ray structure analyses completed. The results of these studies have been used to interpret the outcome
of reactions of Ti(NMe2)4 and Zr(NMe2)4 with borazinylamine preceramic polymers that, upon pyrolysis, produce TiN/BN, ZrN/BN and ZrH0.6N/BN composite powders.
The transamination reactivity of a two-point poly(borazinylamine) oligomer having terminal –NH2 amino groups with Ti(NMe2)4 and Zr(NMe2)4 has been used to obtain metallated preceramic oligomers that, upon pyrolysis, give TiN/BN and ZrN/ZrH0.6N/BN nanocomposites. Model reactions of 1,3,4,5,6-pentamethyl-2-amino borazine, aniline and Ph2NH2 with Ti(NMe2)4 and Zr(NMe2)4 are also described as models for the formation of the metallated oligomers. Molecular structure determinations for the metal
amides are presented.
We dedicate this paper to Professor Christopher W. Allen in recognition of his distinguished career and his accomplishments
in inorganic ring and polymer chemistry. 相似文献
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