Search

Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We first present the general treatment of the steady-state orientational distribution of a segmentally flexible macromolecule with two subunits in an electric field E. The orientation-dependent property that we consider is the electric birefringence Δn, although other electro-optical properties can be derived in the same way. In the low-field region linear in E2 we obtain the Kerr constant of macromolecules with a partially flexible joint, and explicit results are presented for a broken rod. A theory recently proposed by Yoshioka is used for the region of intermediate field strength, where Δn is quadratic in E2. The quadratic constant is also evaluated for hinged rods. For electric field of arbitrary strenght we have devised a Monte Carlo simulation procedure which has been checked using analytical results for straight rods. We have determined the extension of the E2 and E4 regions as a function of flexibility, using Yoshioka’s formulas and the simulation results. Finally, we have used literature data for the Kerr constant of myosin rod and its subfragments to obtain a value of the flexibility parameter that is in agreement with those for other properties. [ABSTRACT FROM AUTHOR]

At any repeating unit of the randomly broken chain model, the direction of the chain can either follow that of the preceding bond, or change at random. The contour-length dependence of the mean-squared end-to-end distance and radius of gyration, when expressed in terms of a persistance length, is found to be the same as that for worm-like chains. However, other moments of the end-to-end distance have a clearly distinct length dependence, as found by computer simulation. Due to the finite probability of a fully extended, straight conformation, the distribution function of the end-to-end distance has a peculiar sharp peak. The similarities and differences between this model and the worm-like chains are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new electrochemical framework for tracking individual soft particles in solution and monitoring their fusion with polarized liquid-liquid interfaces is reported. The physicochemical principle lies in the interfacial transfer of an ionic probe confined in the particles dispersed in solution and that is released upon their collision and fusion with the fluid interface. As a proof-of-concept, spike-like transients of a stochastic nature are reported in the current-time response of 1,2-dichloroethane(DCE)|water(W) submilli-interfaces after injection of DCE-in-W emulsions. The sign and potential dependence of the spikes reflect the charge and lipophilicity of the ionic load of the droplets. A comparison with dynamic light scattering measurements indicates that each spike is associated with the collision of a single sub-picoliter droplet. This opens a new framework for the study of single fusion events at the micro- and nanoscale and of ion transport across biomimetic soft interfaces. [ABSTRACT FROM AUTHOR]

Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)