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111.
112.
I. T. Vieira R. C. H. Cheng P. R. Harper V. de Senna 《Annals of Operations Research》2010,178(1):173-200
It has long been recognised that the structure of social networks plays an important role in the dynamics of disease propagation.
The spread of HIV results from a complex network of social interactions and other factors related to culture, sexual behaviour,
demography, geography and disease characteristics, as well as the availability, accessibility and delivery of healthcare.
The small world phenomenon has recently been used for representing social network interactions. It states that, given some
random connections, the degrees of separation between any two individuals within a population can be very small. In this paper
we present a discrete event simulation model which uses a variant of the small world network model to represent social interactions
and the sexual transmission of HIV within a population. We use the model to demonstrate the importance of the choice of topology
and initial distribution of infection, and capture the direct and non-linear relationship between the probability of a casual
partnership (small world randomness parameter) and the spread of HIV. Finally, we illustrate the use of our model for the
evaluation of interventions such as the promotion of safer sex and introduction of a vaccine. 相似文献
113.
Lu Z Van Wagoner RM Harper MK Hooper JN Ireland CM 《Natural product communications》2010,5(10):1571-1574
Two ring-A-aromatized bile acids, 1 and 2, were isolated from the sponge Sollasella moretonensis, collected from the seabed of northern Queensland. Structures were assigned on the basis of extensive 1D and 2D NMR studies, as well as analysis by HRESIMS. Compound 2 has previously been produced synthetically, though this marks its first isolation from a natural source. 相似文献
114.
Proteins are a diverse class of molecules that can act as catalysts and structural components. Interest in their interactions with ionic solvents is on the increase due to the tuneable possibilities for non-aqueous biocatalysis, improved thermostability of biomaterials, and possible roles in medicine, such as drug delivery and use as cell-growth scaffolds. We summarise here the recent examples of these exciting new aspects of protein-ionic solvent interactions, highlighting future directions. 相似文献
115.
116.
We report on one aspect of an extended research and development project that was conducted to support teachers?? development of mathematical knowledge for teaching (MKT) algebra through participation and authentic engagement in online collaborative mathematical problem solving. This article expands on our recent work, which has succeeded in developing a model for supporting teachers?? mathematical development at a distance that has shown great promise for supporting significant gains in teachers?? MKT. Specifically, this ex-post-facto analysis consisted of qualitative, micro-level analysis of the content of teachers?? activity and generated artifacts and helps us understand how the various collaborative activities (specific combinations of interaction, instructor support and feedback, and technology) supported and/or constrained the development of MKT algebra in an online environment. 相似文献
117.
118.
Tasnádi G Winkler CK Clay D Sultana N Fabian WM Hall M Ditrich K Faber K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(33):10362-10367
The degree of C?C bond activation in the asymmetric bioreduction of α,β-unsaturated carboxylic esters by ene-reductases was studied, and general recommendations to render these "borderline-substrates" more reactive towards enzymatic reduction are proposed. The concept of "supported substrate activation" was developed. In general, an additional α-halogenated substituent proved to be beneficial for enzymatic activity, whereas β-alkyl or β-aryl substituents were detrimental for the reactivity of nonhalogenated substrates, and α-cyano groups showed little effect. The alcohol moiety of the ester functionality was found to have a strong influence on the reaction rate. Overall, activities were determined by both steric and electronic effects. 相似文献
119.
A. Yu. Plotski A. A. Sysoliatin A. I. Latkin V. F. Khopin P. Harper J. Harrison S. K. Turitsyn 《JETP Letters》2007,85(7):319-322
The experimental results for the propagation of high-power pulses in fibers with length-varying chromatic dispersion are presented. 相似文献
120.
Harper SM Neil LC Day IJ Hore PJ Gardner KH 《Journal of the American Chemical Society》2004,126(11):3390-3391
Phototropins are light-activated kinases from plants that utilize light-oxygen-voltage (LOV) domains as blue light photosensors. Illumination of these domains leads to the formation of a covalent linkage between the protein and an internally bound flavin chromophore, destabilizing the surrounding protein and displacing an alpha-helix from its surface. Here we use a combination of spectroscopic tools to monitor the kinetic processes that spontaneously occur in the dark as the protein returns to the noncovalent ground state. Using time-resolved two-dimensional (2D) NMR methods, we measured the rate of this process at over 100 independent sites throughout the protein, establishing that regeneration of the dark state occurs cooperatively within a 1.6-fold range of observed rates. These data agree with other spectroscopic measurements of the kinetics of protein/FMN bond cleavage and global conformational changes, consistent with these processes experiencing a common rate-limiting step. Arrhenius analyses of the temperature dependence of these rates suggest that the transition state visited during this regeneration has higher energy than the denatured form of this protein domain despite the fact that there is no global unfolding of the domain during this process. 相似文献