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101.
Bentley R 《Natural product reports》2008,25(1):118-138
Tropones and tropolones have been of increasing interest in the past few years; approximately 200 such materials occur in nature. This article reviews the distribution of these materials, the biosynthetic pathways for their production and their biological activities. There are 154 references. 相似文献
102.
Computations provide insight to the stability and isomeric possibilities of thiotropocin, tropodithietic acid, and troposulfenin. Thiotropocin and tropodithietic acid contain a flat 7-membered ring and delocalized pi-bonds similar to those of tropylium ion (C(7)H(7)(+)). Troposulfenin is far less stable; it contains a puckered tropone ring and localized bonds similar to 1,3,5-cycloheptatriene. A facile 1,5-hydrogen shift suggests that thiotropocin and tropodithietic acid exist as a pair of interconverting tautomers. Loss of an acidic proton from these three tautomers produces the same conjugate base structure. 相似文献
103.
104.
E. K. Johansson D. Rudolph J. Ekman C. Fahlander C. Andreoiu M. A. Bentley M. P. Carpenter R. J. Charity R. M. Clark P. Fallon R. V. F. Janssens F. G. Kondev T. L. Khoo T. Lauritsen A. O. Macchiavelli W. Reviol D. G. Sarantites D. Seweryniak C. E. Svensson S. J. Williams 《The European Physical Journal A - Hadrons and Nuclei》2006,27(2):157-165
The doubly magic N = Z nucleus 56Ni has been investigated with two fusion-evaporation reactions; 40Ca(28Si, 3α)56Ni at a beam energy of 122MeV and 28Si(32S, 2p2n)56Ni at 130MeV. To detect γ-rays in coincidence with evaporated particles the Ge-detector array Gammasphere was used in conjunction
with the charged-particle detector system, Microball and a 1π neutron detector array. Results include a significantly extended
level scheme of 56Ni, which is compared to large-scale shell model calculations in the fp shell. The experimental and theoretical results agree to a large extent, with one notable exception; the theoretical model
fails to predict the proper sequence of the yrast and yrare 8+ states. 相似文献
105.
K. B. Alexander D. M. Kroeger J. Bentley J. Brynestad 《Physica C: Superconductivity and its Applications》1991,180(5-6):337-350
The grain boundary segregation behavior of stoichiometric and off-stoichiometric YBa2Cu3O7−x has been studied with analytical electron microscopy (AEM) to complement previous results obtained with Auger electron spectroscopy (AES). It was observed that the grain boundary segregation levels varied from boundary to boundary. In stoichiometry material, excess copper and deficient oxygen were observed at the grain boundaries. In materials containing excess barium, excess yttrium and deficient copper levels were observed at the grain boundaries. The grain boundary segregation levels in the materials containing excess barium can be related to the resistivity and critical current density results. Preferential segregation to specific sites in grain boundaries was observed by AEM. The effect of grain boundary segregation on the superconducting properties of these materials is discussed in terms of the weak link behavior and a possible percolative mechanism in order to maintain a continuous current path. 相似文献
106.
Pham Minh-Quan K. Harvey Steven P. Weigand William A. Bentley William E. 《Applied biochemistry and biotechnology》1996,57(1):779-789
Applied Biochemistry and Biotechnology - An environmentally benign method for the mineralization of sulfur mustard has been proposed involving chemical hydrolysis of sulfur mustard to thiodiglycol,... 相似文献
107.
108.
Cheng Y Luo X Tsao CY Wu HC Betz J Payne GF Bentley WE Rubloff GW 《Lab on a chip》2011,11(14):2316-2318
Programmable 3D cell assembly under physiological pH conditions is achieved using electrodeposited stimuli-responsive alginate gels in a microfluidic device, with parallel sidewall electrodes enabling direct observation of the cell assembly. Electrically triggered assembly and subsequent viability of mammalian cells is demonstrated, along with spatially programmable, multi-address assembly of different strains of E. coli cells. Our approach enables in vitro study of dynamic cellular and inter-cellular processes, from cell growth and stimulus/response to inter-colony and inter-species signaling. 相似文献
109.
In this study, the organization of collagen fibrils within the sclera of the eye was investigated using the 7 keV hard X-ray microscope of the Pohang light source and compared to images from electron and atomic force microscopy. From the captured X-ray images, individual collagen fibrils were observed clearly in a spatial resolution much better than 100 nm, both in longitudinal sections and in transverse sections. Some of the collagen fibrils showed evidence of axial periodicity. In some regions of the samples, we could see cross-bridge like structures between adjacent collagen fibrils. The X-ray microscope also allowed the observation of keratocytes and the lamella structure of the scleral stroma. The X-ray microscope has some unique advantages in the nano-scale imaging of bio-samples relative to other established imaging techniques. 相似文献
110.
Jason Bentley Qinglin Huang Yoshiaki Kawajiri Mladen Eic Andres Seidel-Morgenstern 《Adsorption》2011,17(1):159-170
The resolution of racemic gas mixtures by simulated moving bed (SMB) and pressure swing adsorption (PSA) is investigated by dynamic simulation and optimization. Enantiomer separation of inhalation anesthetics is important because there is evidence that the purified enantiomers may have different pharmacological properties than the racemate. The model parameters reported in an experimental investigation performed elsewhere are used to study the feasibility of this separation using SMB and PSA configurations. Both processes were modeled in gPROMS® as systems of differential algebraic equations. Operating conditions are optimized such that the feed throughput and product recovery for each process were maximized subject to equal constraints on the pressures and superficial gas velocities. SMB was found to be capable of resolving racemic feed mixtures with purity and recovery exceeding 99%. On the other hand, PSA was also able to provide a single purified enantiomer with low recovery of about 30% which may limit its application to enantiomer separation. Nevertheless, PSA consumes less desorbent, and achieves higher throughput at the sacrifice of lower recovery. 相似文献