Conceptual aspects of line tensions

We analyze two representative systems containing a three-phase-contact line: a liquid lens at a fluid--fluid interface and a liquid drop in contact with a gas phase residing on a solid substrate. We discuss to which extent the decomposition of the grand canonical free energy of such systems into volume, surface, and line contributions is unique in spite of the freedom one has in positioning the Gibbs dividing interfaces. In the case of a lens it is found that the line tension is independent of arbitrary choices of the Gibbs dividing interfaces. In the case of a drop, however, one arrives at two different possible definitions of the line tension. One of them corresponds seamlessly to that applicable to the lens. The line tension defined this way turns out to be independent of choices of the Gibbs dividing interfaces. In the case of the second definition,however, the line tension does depend on the choice of the Gibbs dividing interfaces. We provide equations for the equilibrium contact angles which are form-invariant with respect to notional shifts of dividing interfaces which only change the description of the system. Conceptual consistency requires to introduce additional stiffness constants attributed to the line. We show how these constants transform as a function of the relative displacements of the dividing interfaces. The dependences of the contact angles on lens or drop volumes do not render the line tension alone but a combination of the line tension, the Tolman length, and the stiffness constants of the line.Comment: 34 pages, 9 figure

NEOPLASIA TROFOBLÁSTICA GESTACIONAL: HOSPITAL FÉLIX BULNES CERDA, 1992 - 2002

Objetivo: Analizar los hallazgos clínicos y el seguimiento de los casos de neoplasia trofoblástica gestacional. Material y Métodos: Se revisaron todos los casos de mola hidatidiforme en el Hospital Félix Bulnes Cerda, entre los años 1992 y 2002. Resultados: Se diagnosticaron 79 casos. La edad promedio de las pacientes fue 26,4 años. El diagnóstico de mola hidatidiforme fue sospechado clínicamente en 75,6% y en 24,4% fue hallazgo anatomopatológico. Los principales síntomas al ingreso fueron: dolor hipogástrico (75,6%), náuseas y/o vómitos (32,1%) y disuria (19,2%). Entre los signos clínicos destacan sangrado vaginal (83,3%), altura uterina discordante (25,3%) y expulsión de vesículas (12,8%). La ecografía concluyó mola hidatidiforme en 74,4% y quistes tecaluteínicos en 23,1%. Los hallazgos de anatomía patológica fueron mola completa (61,5%), mola parcial (31,2%) y coriocarcinoma (1,3%). En el seguimiento, 30,8% no volvieron a control y 23,1% tuvieron entre 7 y 12 controles. Conclusión: Los hallazgos de este estudio son similares a los descritos en la literatur

Soft Photons in Hadron-Hadron Collisions: Synchrotron Radiation from the QCD Vacuum?

We discuss the production of soft photons in high energy hadron-hadron collisions. We present a model where quarks and antiquarks in the hadrons emit ``synchrotron light'' when being deflected by the chromomagnetic fields of the QCD vacuum, which we assume to have a nonperturbative structure. This gives a source of prompt soft photons with frequencies $\omega <= 300 MeV$ in the c.m. system of the collision in addition to hadronic bremsstrahlung. In comparing the frequency spectrum and rate of ``synchrotron'' photons to experimental results we find some supporting evidence for their existence. We make an exclusive--inclusive connection argument to deduce from the ``synchrotron'' effect a behaviour of the neutron electric formfactor $G_E^n(Q^2)$ proportional to $(Q^2)^{1/6}$ for $Q^2 < 20 fm^{-2}$. We find this to be consistent with available data. In our view, soft photon production in high energy hadron-hadron and lepton-hadron collisions as well as the behaviour of electromagnetic hadron formfactors for low $Q^2$ are thus sensitive probes of the nonperturbative structure of the QCD vacuum.Comment: Heidelberg preprint HD-THEP-94-36, 31 pages, LaTeX + ZJCITE.sty (included), 12 figures appended as uuencoded compressed ps-fil

Attenuated and Protease-Profile Modified Sendai Virus Vectors as a New Tool for Virotherapy of Solid Tumors

Peer reviewe

Elastic Mid-Infrared Light Scattering: a Basis for Microscopy of Large-Scale Electrically Active Defects in Semiconducting Materials

A method of the mid-IR-laser microscopy has been proposed for the investigation of the large-scale electrically and recombination active defects in semiconductors and non-destructive inspection of semiconductor materials and structures in the industries of microelectronics and photovoltaics. The basis for this development was laid with a wide cycle of the investigations on the low-angle mid-IR-light scattering in semiconductors. The essence of the technical idea was to apply the dark-field method for spatial filtering of the scattered light in the scanning mid-IR-laser microscope. This approach enabled the visualization of large-scale electrically active defects which are the regions enriched with ionized electrically active centers. The photoexcitation of excess carriers within a small volume located in the probe mid-IR-laser beam enabled the visualization of the large-scale recombination-active defects like those revealed in the optical or electron beam induced current methods. Both these methods of the scanning mid-IR-laser microscopy are now introduced in detail in the present paper as well as a summary of techniques used in the standard method of the lowangle mid-IR-light scattering itself. Besides the techniques for direct observations, methods for analyses of the defect composition associated with the mid-IR-laser microscopy are also discussed in the paper.Comment: 44 pages, 13 figures. A good oldi