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61.
The influence of high uniaxial stress on the ΓI,C conduction band effective mass of gallium arsenide
J.C. Portal R.A. Cooke R.A. Stradling A.R. Adams C.N. Ahmad 《Solid State Communications》1980,34(5):335-338
From a study of the Zeeman splitting of the shallow donor states, the variation of the effective mass in the ΓIC conduction band minimum of gallium arsenide has been measured as a function of applied uniaxial stress. The effective mass is found to be proportional to the stress, the percentage increase being (0.23 ± 0.06), (0.115 ± 0.015) and (0.075 ± 0.015) kbar?1 for 〈100〉, 〈110〉 and 〈111〉 stress respectively. The precision inherent in the far-infrared technique employed is greater than that of previous experimental methods. 相似文献
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Self-similar solutions to the Riemann problem for water with the modified Tait equation of state are presented. The methods of Smoller for gas dynamics are employed to reduce the problem to the solution of a single non-linear equation. The same methods are used for solving the Riemann problem at a gas-water interface. In both cases the method of interval bisections affords a solution technique free of problems with convergence. 相似文献
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Stochasticity is an inherent feature of complex systems with nanoscale structure. In such systems information is represented by small collections of elements (e.g., a few electrons on a quantum dot), and small variations in the populations of these elements may lead to big uncertainties in the information. Unfortunately, little is known about how to work within this inherently noisy environment to design robust functionality into complex nanoscale systems. Here, we look to the biological cell as an intriguing model system where evolution has mediated the trade-offs between fluctuations and function, and in particular we look at the relationships and trade-offs between stochastic and deterministic responses in the gene expression of budding yeast (Saccharomyces cerevisiae). We find gene regulatory arrangements that control the stochastic and deterministic components of expression, and show that genes that have evolved to respond to stimuli (stress) in the most strongly deterministic way exhibit the most noise in the absence of the stimuli. We show that this relationship is consistent with a bursty two-state model of gene expression, and demonstrate that this regulatory motif generates the most uncertainty in gene expression when there is the greatest uncertainty in the optimal level of gene expression. 相似文献
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We have calculated the stability of two of the low-index surfaces known to dominate the morphology of ZnO as a function of stoichiometry. These two surfaces are (10(-)10) and (11(-)20). In each case, two terminations only are stable for a significant range of oxygen and hydrogen chemical potential: the pure stoichiometric surface and a surface covered in a monolayer of water. The mode by which the water adsorbs is however different for the two surfaces considered. On the (10(-)10) surface the close proximity of the water molecules means hydrogen bonding can occur between adjacent chemiabsorbed water molecules and hence there is little difference in the stability of the hydrated and hydroxylated surface, and in fact the most stable surface occurs with a combination of dissociated and undissociated water adsorption. In the case of the (11(-)20) surface, it is only when full dissociation has occurred that a hydrogen-bonding network can form. Our results also show good agreement between DFT and atomistic simulations, suggesting that potential based methods can usefully be applied to ZnO. 相似文献
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Ruthenium‐Containing Linear Helicates and Mesocates with Tuneable p53‐Selective Cytotoxicity in Colorectal Cancer Cells 下载免费PDF全文
Dr. Simon J. Allison Dr. David Cooke Francesca S. Davidson Prof. Paul I. P. Elliott Dr. Robert A. Faulkner Hollie B. S. Griffiths Owen J. Harper Omar Hussain Prof. P. Jane Owen‐Lynch Prof. Roger M. Phillips Prof. Craig R. Rice Samantha L. Shepherd Dr. Richard T. Wheelhouse 《Angewandte Chemie (International ed. in English)》2018,57(31):9799-9804
The ligands L1 and L2 both form separable dinuclear double‐stranded helicate and mesocate complexes with RuII. In contrast to clinically approved platinates, the helicate isomer of [Ru2( L1 )2]4+ was preferentially cytotoxic to isogenic cells (HCT116 p53?/?), which lack the critical tumour suppressor gene. The mesocate isomer shows the reverse selectivity, with the achiral isomer being preferentially cytotoxic towards HCT116 p53+/+. Other structurally similar RuII‐containing dinuclear complexes showed very little cytotoxic activity. This study demonstrates that alterations in ligand or isomer can have profound effects on cytotoxicity towards cancer cells of different p53 status and suggests that selectivity can be “tuned” to either genotype. In the search for compounds that can target difficult‐to‐treat tumours that lack the p53 tumour suppressor gene, [Ru2( L1 )2]4+ is a promising compound for further development. 相似文献
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Jordan BJ Pollier MA Ofir Y Joubanian S Mehtala JG Sinkel C Caldwell ST Kennedy A Rabani G Cooke G Rotello VM 《Chemical communications (Cambridge, England)》2008,(14):1653-1655
We report the modulation of the absorbance of a flavin push-pull derivative through specific recognition by a complementary diamidopyridine (DAP), shifting the flavin intramolecular charge transfer band by approximately 30 nm. 相似文献
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Caldwell ST Cooke G Cooper A Nutley M Rabani G Rotello V Smith BO Woisel P 《Chemical communications (Cambridge, England)》2008,(23):2650-2652
A biotinylated 1,5-dialkoxynaphthalene derivative has been shown to have the ability to bind strongly to avidin and thus act as an artificial binding site for cyclobis(paraquat-p-phenylene) thereby facilitating the formation of a tuneable pseudorotaxane-based bioconjugate. 相似文献