52 resultados para CYLINDRICAL CONFIGURATION


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The domain configuration of micron-sized permalloy ellipses was studied under the influence of an in-plane rotating magnetic field using magnetic force microscopy. The field amplitude was chosen such that when the field is applied parallel to the long axis of the ellipses they are saturated, but when the field is perpendicular to the long axis they exhibit multi-domain states. The rotation angle for nucleation and annihilation of domains was determined for different magnitudes of the applied magnetic field and for two different lateral sizes of ellipses, 6 Am x 2 Am and 3 Am x 1 Am. It was found that both nucleation and annihilation occur over a range of angles for both lateral sizes of ellipses. Saturated states are stable for a wider range of angles for larger values of the applied field.

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Purpose: To determine the intra- and interobserver agreement in assessing the configuration of the human anterior chamber angle using ultrasound biomicroscopy (UBM). Methods: Two masked clinicians used ubm images to estimate, in 41 eyes, (a) the position of contact between the peripheral iris and the inside of the eye wall, (b) the angular size of the anterior chamber angle (ACA), and (c) the curvature of the peripheral iris. Both observers, masked to the previous results, examined the same images in a second session. Agreement was evaluated using the unweighted ? statistic. Results: Intraobserver agreement in assessing the iris insertion, angular width, and the iris curvature was high (range of ? values, 0.83-0.92). Interobserver agreement in evaluating the level of iris insertion (? = 0.79), the angular width (? = 0.95), and the iris curvature (? = 0.84) was also high. Conclusion: The agreement within the same observer and between observers in evaluating the ACA configuration by UBM was excellent.

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Manipulator motion planning is a task which relies heavily on the construction of a configuration space prior to path planning. However when fast real-time motion is needed, the full construction of the manipulator's high-dimensional configu-ration space can be too slow and expensive. Alternative planning methods, which avoid this full construction of the manipulator's configuration space are needed to solve this problem. Here, one such existing local planning method for manipulators based on configuration-sampling and subgoal-selection has been extended. Using a modified Artificial Potential Fields (APF) function, goal-configuration sampling and a novel subgoal selection method, it provides faster, more optimal paths than the previously proposed work. Simulation results show a decrease in both runtime and path lengths, along with a decrease in unexpected local minimum and crashing issues.

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Stereochemical evidence is presented to demonstrate that (−)-inthomycin C has (3R)- and not (3S)-stereochemistry. Careful reappraisal of the previously published work2−5 now indicates that the Hatakeyama, Hale, Ryu, and Taylor teams all have synthesized (−)-(3R)-inthomycin C. The newly measured [α]D of pure (−)-(3R)-inthomycin C (98% ee) is −7.9 (c 0.33, CHCl3) and not −41.5 (c 0.1, CHCl3) as was previously reported in 2012.

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WcaJ is an Escherichia coli membrane enzyme catalysing the biosynthesis of undecaprenyl-diphosphate-glucose, the first step in the assembly of colanic acid exopolysaccharide. WcaJ belongs to a large family of polyisoprenyl-phosphate hexose-1-phosphate transferases (PHPTs) sharing a similar predicted topology consisting of an N-terminal domain containing four transmembrane helices (TMHs), a large central periplasmic loop, and a C-terminal domain containing the fifth TMH (TMH-V) and a cytosolic tail. However, the topology of PHPTs has not been experimentally validated. Here, we investigated the topology of WcaJ using a combination of LacZ/PhoA reporter fusions and sulfhydryl
labelling by PEGylation of novel cysteine residues introduced into a cysteine-less WcaJ. The results showed that the large central loop and the C-terminal tail both reside in the cytoplasm and are separated by TMH-V, which does not fully span the membrane, likely forming a "hairpin" structure. Modelling of TMH-V revealed that a highly conserved proline might contribute to a helix-break-helix structure in all PHPT members. Bioinformatic analyses show that all of these features are conserved in PHPT homologues from
Gram-negative and Gram-positive bacteria. Our data demonstrate a novel topological configuration for PHPTs, which is proposed as a signature for all members of this enzyme family