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31.
A method is described that solves the problem of determining the correct birefringence and orientation angle of samples having multiple orders of retardation. The approach simultaneously uses two wavelengths of light combined with modulation of the polarization vector using a high-speed rotating half waveplate. The simultaneous application of two wavelengths is possible with the use of an achromatic waveplate. The technique is demonstrated by performing start-up Couette flow experiments on a concentrated polystyrene solution that produced multiple orders in retardation. 相似文献
32.
Wong SY Moskowitz JS Veselinovic J Rosario RA Timachova K Blaisse MR Fuller RC Klibanov AM Hammond PT 《Journal of the American Chemical Society》2010,132(50):17840-17848
Here we present a new bifunctional layer-by-layer (LbL) construct made by combining a permanent microbicidal polyelectrolyte multilayered (PEM) base film with a hydrolytically degradable PEM top film that offers controlled and localized delivery of therapeutics. Two degradable film architectures are presented: (1) bolus release of an antibiotic (gentamicin) to eradicate initial infection at the implant site, or (2) sustained delivery of an anti-inflammatory drug (diclofenac) to cope with inflammation at the site of implantation due to tissue injury. Each degradable film was built on top of a permanent base film that imparts the implantable device surface with microbicidal functionality that prevents the formation of biofilms. Controlled-delivery of gentamicin was demonstrated over hours and that of diclofenac over days. Both drugs retained their efficacy upon release. The permanent microbicidal base film was biocompatible with A549 epithelial cancer cells and MC3T3-E1 osteoprogenitor cells, while also preventing bacteria attachment from turbid media for the entire duration of the two weeks studied. The microbicidal base film retains its functionality after the biodegradable films have completely degraded. The versatility of these PEM films and their ability to prevent biofilm formation make them attractive as coatings for implantable devices. 相似文献
33.
Daniel?R.?Fuller Matthew?S.?Glover Nicholas?A.?Pierson DoYong?Kim David?H.?Russell David?E.?ClemmerEmail author 《Journal of the American Society for Mass Spectrometry》2016,27(8):1376-1382
Ion mobility/mass spectrometry techniques are employed to investigate the binding of Zn2+ to the nine-residue peptide hormone oxytocin (OT, Cys1-Tyr2-Ile3-Gln4-Asn5-Cys6-Pro7-Leu8-Gly9-NH2, having a disulfide bond between Cys1 and Cys6 residues). Zn2+ binding to OT is known to increase the affinity of OT for its receptor [Pearlmutter, A. F., Soloff, M. S.: Characterization of the metal ion requirement for oxytocin-receptor interaction in rat mammary gland membranes. J. Biol. Chem. 254, 3899–3906 (1979)]. In the absence of Zn2+, we find evidence for two primary OT conformations, which arise because the Cys6–Pro7 peptide bond exists in both the trans- and cis-configurations. Upon addition of Zn2+, we determine binding constants in water of KA = 1.43 ± 0.24 and 0.42 ± 0.12 μM?1, for the trans- and cis-configured populations, respectively. The Zn2+ bound form of OT, having a cross section of Ω = 235 Å2, has Pro7 in the trans-configuration, which agrees with a prior report [Wyttenbach, T., Liu, D., Bowers, M. T.: Interactions of the hormone oxytocin with divalent metal ions. J. Am. Chem. Soc. 130, 5993–6000 (2008)], in which it was proposed that Zn2+ binds to the peptide ring and is further coordinated by interaction of the C-terminal, Pro7-Leu8-Gly9-NH2, tail. The present work shows that the cis-configuration of OT isomerizes to the trans-configuration upon binding Zn2+. In this way, the proline residue regulates Zn2+ binding to OT and, hence, is important in receptor binding. 相似文献
34.
Lee JJ Fuller RO Sobolev AN Clausen HF Overgaard J Koutsantonis GA Iversen BB Spackman MA 《Chemical communications (Cambridge, England)》2011,47(7):2029-2031
The title compound undergoes two order-disorder transitions between 15 and 299 K, dictated by ordering of the guest molecules in the host cages, and resulting in three related crystal structures. We anticipate behaviour of this kind to be widespread, and speculate that the concept of "the crystal structure" for individual Dianin's clathrates may be elusive. 相似文献
35.
M. E. Keillor L. E. Erikson C. E. Aalseth A. R. Day E. S. Fuller B. D. Glasgow E. W. Hoppe T. W. Hossbach L. K. Mizouni A. W. Myers C. T. Overman A. Seifert T. J. Stavenger 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(2):683-687
The Pacific Northwest National Laboratory (PNNL) is currently developing a custom software suite capable of automating many of the tasks required to accurately analyze coincident signals within gamma spectrometer arrays. During the course of this work, significant crosstalk was identified in the energy determination for spectra collected with a new low-background intrinsic germanium (HPGe) array at PNNL. The HPGe array is designed for high detection efficiency, ultra-low-background performance, and sensitive γ–γ coincidence detection. The first half of the array, a single cryostat containing seven HPGe crystals, was recently installed into a new shallow underground laboratory facility. This update will present a brief review of the germanium array, describe the observed crosstalk, and present a straight-forward empirical correction that significantly reduces the impact of this crosstalk on the spectroscopic performance of the system. 相似文献
36.
In Part 1 of this paper, we noted the systematic errors in the estimates of means and standard deviations produced by a rapid approximation applied to a model of hydrocarbon discovery. In Part 2, we apply regression to predict the approximation errors, as functions of model parameters and approximation output. With the regression model, we can correct much of the error in the approximation, as we illustrate with data from the Nisku-Shelf play of western Canada. 相似文献
37.
38.
On the finitistic dimension conjecture for artinian rings 总被引:1,自引:0,他引:1
39.
Michael J. Fuller E.Bright Wilson Walther Caminati 《Journal of Molecular Spectroscopy》1982,96(1):131-145
The rotational spectra of two conformations of 3-chloro-propanol were observed for the four possible and isotopic species. For both conformations the oxygen atom is gauche with respect to the C2C3 bond and the hydroxyl hydrogen is trans with respect to the C2C1 bond. In one conformation (T) the chlorine is trans with respect to C1C2 and it is gauche in the other form (G). The ground state of the G form is about 0.7 kcal/mole more stable than that of the T form. A discussion is given about the failure to observe the H bond species. The most likely reason is the too close approach of Cl and O in this hypothetical configuration. The quadrupole coupling constants were obtained for the G form. The rotational spectra of five excited states of the T form and of one excited state of the G species were measured. Partial r0 and rs structures are given. 相似文献
40.
Using a transmission line theory, expressions for the propagation constant and characteristic impedance of a borehole antenna
are derived. Both air-filled and fluid-filled holes are considered. The required modal equation is solved by a rapidly convergent
iterative method. Some data for the input impedance and effective dipole moment for the terminated line are then provided.
It appears that the presence of conducting fluid in the hole will not seriously impair the effectiveness of the radiating
structure, but the voltage gradients in the insulation will be increased markedly. 相似文献