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151.
DNA was studied in lipid reverse micelles with the aim of investigating the interactions of DNA with lipids in a restricted compartment with minimal water content. Circular dichroic (CD) spectra of DNA at low water content showed the characteristic polymer-salt-induced (psi) spectra of condensed DNA. Dynamic light scattering showed a peak around a radius of 400 nm (corresponding to DNA-containing micelles), and a peak around 2.5 nm (corresponding to "empty" micelles). Fourier Transform-IR (FT-IR) spectroscopy was carried out and analyzed in terms of three distinct states of water inside the micelle water pool, where the local concentration of DNA reached an estimated value of ca. 600 mg/mL, comparable to that found in restricted biological compartments. 相似文献
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Metastasis, the dissemination of tumor cells to distant organs, is often associated with fatal outcome in cancer patients. Formation of metastasis requires degradation of extracellular matrices and several families of proteases have been implicated in this process, including matrix metalloproteinases (MMPs), serine and cysteine proteases. Inhibition of these enzymes in animal models of metastasis has shown impressive therapeutic effects. This report discusses the various approaches used for enzyme inhibition and describes new developments in drug design for inhibition of proteases in metastatic disease. 相似文献
155.
Shahriar Sajjadi 《Journal of polymer science. Part A, Polymer chemistry》2002,40(10):1652-1663
Particle nucleation in the seeded emulsion polymerization of styrene in the presence of Aerosol‐MA emulsifier micelles and in the absence of monomer droplets (interval III) was investigated. The seed particles were swollen with different amounts of the styrene monomer before the experiments. A larger number of polymer particles formed in interval III than in the corresponding seeded batch operation in the presence of monomer droplets. The increase in the number of particles could be attributed to the reduced rate of growth of new particles, which retarded the depletion of emulsifier micelles. The number of secondary particles initially increased with the initial polymer weight ratio in the seed particles (wp0) but decreased at a higher range of wp0, after reaching a maximum at wp0 = 0.60, and eventually was reduced to zero. At high values of wp0 (>0.75), polymerization occurred in the seed particles, whereas few or no new particles were formed despite the presence of micelles. The cessation of particle formation at high conversions was ascertained with a semibatch process in which the neat monomer feed was added to the reaction vessel containing the seed particles and emulsifier micelles. For wp0 > 0.85, the emulsifier micelles were disintegrated to stabilize the seed particles with no secondary particle formation. The possible reasons for the cessation of particle formation at high wp0 were examined. The size distribution of secondary particles showed a positive skewness in terms of volume because of the declining rate of growth for particles, together with a low rate of growth for small particles. The distribution breadth of new particles sharpened with increasing wp0. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1652–1663, 2002 相似文献
156.
We report observation of high contrast Raman-Ramsey fringes using time delayed optical pulse pairs in a rubidium vapor cell. The width of these fringes are not limited by saturation and provides a simpler means to produce narrow atomic linewidths using a thermal vapor medium for compact atomic clock applications. We also demonstrate phase-scanned Raman-Ramsey fringes, with potential application to sensitive detection of trace vapors. 相似文献
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Bio-inspired optimization algorithms for optical parameter extraction of dielectric materials: A comparative study 下载免费PDF全文
Particle swarm optimization(PSO) and invasive weed optimization(IWO) algorithms are used for extracting the modeling parameters of materials useful for optics and photonics research community. These two bio-inspired algorithms are used here for the first time in this particular field to the best of our knowledge. The algorithms are used for modeling graphene oxide and the performances of the two are compared. Two objective functions are used for different boundary values. Root mean square(RMS) deviation is determined and compared. 相似文献
159.
Reza Azin Seyed Mostafa Jafari Raad Shahriar Osfouri Rooholla Fatehi 《Heat and Mass Transfer》2013,49(11):1603-1612
Storage and disposal of greenhouse gases in saline aquifers is an important solution for reduction of these gases from atmosphere. Understanding the concepts and mechanisms involved in the storage process, especially natural convection and their impact on long-term fate of injected CO2 are essential. Natural convection is an effective mechanism which increases solubility of carbon dioxide in the storage process. In this work, injection of carbon dioxide into aquifer is numerically simulated. First, numerical criteria are developed to provide numerical accuracy and stability by mesh resolution. Then, changes in input wave number in surface perturbation and order of element used in finite element method were analyzed. It was found that depending on Rayleigh number, there is a wave number at which instability occurs earlier and grows faster. Also, onset of CO2 convective mixing in saline aquifers was obtained and correlated for a number of field cases. Results show that onset of convection can be approximated by a scaling relationship for dimensionless time as a function of inverse square of Rayleigh number, Ra ?2, for Rayleigh range used in this work. This scaling relationship provides a predictive tool for onset of convection and also long-term fate of disposed CO2 in large scale geological sequestration. 相似文献
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Barra Valeria Afkhami Shahriar Kondic Lou 《The European physical journal. E, Soft matter》2019,42(1):1-23
The European Physical Journal E - The phenomena on the capillarity-driven migration of small objects are full of interest for both scientific and engineering communities, and a critical review is... 相似文献