Prolame produces anxiolytic- and antidepressant-like effects in middle-aged female rats with less uterotrophic effects than 17ß-estradiol.

Estrogen hormone replacement therapy (EHRT), improving women's life quality at menopause, reduces anxiety and depression symptoms associated with ovarian hormonal decline. However, its potential adverse effects, like thromboembolism and cancer risk, limit its use. Prolame is a synthetic 17ß-amino estrogen with antithrombotic actions that exerts anxiolytic- and antidepressant-like effects on young adult ovariectomized female rats. It is unknown if prolame's effects may be observed in age and endocrine conditions emulating menopause. This study aimed to identify the antidepressant- and anxiolytic-like effects of prolame and E2 (used as a reference estrogen treatment) in middle-aged female rats coursing with irregular cycles, in two different conditions: ovariectomized or gonadally intact. Results were compared with those from young adult ovariectomized rats. Prolame (60 or 120 µg/kg), 17ß-estradiol (E2, 40 or 80 µg/kg), or vehicle were chronically administered, and their effects were evaluated in the elevated plus-maze, defensive burying behavior test, open field test, and forced swimming test. Uterotrophic actions were estimated by uterine weight related to body weight. Prolame and E2 produced robust anxiolytic- and antidepressant-like effects in young adult ovariectomized rats, but these effects were absent in gonadally intact middle-aged rats. Interestingly, only prolame induced anxiolytic- and antidepressant-like effects in middle-aged ovariectomized rats. Uterotrophic effects of prolame were weaker than E2 effects, notably in middle-aged females. Altogether, present data support the notion that prolame has the potential to be considered an EHRT with relevant psychoactive actions and with apparently lower adverse-side effects, especially in middle-aged populations.

Polycrystalline Ni nanotubes under compression: a molecular dynamics study.

Mechanical properties of nanomaterials, such as nanowires and nanotubes, are an important feature for the design of novel electromechanical nano-architectures. Since grain boundary structures and surface modifications can be used as a route to modify nanostructured materials, it is of interest to understand how they affect material strength and plasticity. We report large-scale atomistic simulations to determine the mechanical response of nickel nanowires and nanotubes subject to uniaxial compression. Our results suggest that the incorporation of nanocrystalline structure allows completely flexible deformation, in sharp contrast with single crystals. While crystalline structures at high compression are dominated by dislocation pinning and the multiplication of highly localized shear regions, in nanocrystalline systems the dislocation distribution is significantly more homogeneous. Therefore, for large compressions (large strains) coiling instead of bulging is the dominant deformation mode. Additionally, it is observed that nanotubes with only 70% of the nanowire mass but of the same diameter, exhibit similar mechanical behavior up to 0.3 strain. Our results are useful for the design of new flexible and light-weight metamaterials, when highly deformable struts are required.

Transport inefficiency in branched-out mesoscopic networks: an analog of the Braess paradox.

We present evidence for a counterintuitive behavior of semiconductor mesoscopic networks that is the analog of the Braess paradox encountered in classical networks. A numerical simulation of quantum transport in a two-branch mesoscopic network reveals that adding a third branch can paradoxically induce transport inefficiency that manifests itself in a sizable conductance drop of the network. A scanning-probe experiment using a biased tip to modulate the transmission of one branch in the network reveals the occurrence of this paradox by mapping the conductance variation as a function of the tip voltage and position.

Scanning gate microscopy of quantum rings: effects of an external magnetic field and of charged defects.

We study scanning gate microscopy (SGM) in open quantum rings obtained from buried semiconductor InGaAs/InAlAs heterostructures. By performing a theoretical analysis based on the Keldysh-Green function approach we interpret the radial fringes observed in experiments as the effect of randomly distributed charged defects. We associate SGM conductance images with the local density of states (LDOS) of the system. We show that such an association cannot be made with the current density distribution. By varying an external magnetic field we are able to reproduce recursive quasi-classical orbits in LDOS and conductance images, which bear the same periodicity as the Aharonov-Bohm effect.

Production and characterization of single-crystal FeCo nanowires inside carbon nanotubes.

We describe the synthesis of novel monocrystalline FeCo nanowires encapsulated inside multiwalled carbon nanotubes (MWNTs). These FeCo nanowires exhibit homogeneous Fe and Co concentrations and do not contain an external oxide layer due to the presence of insulating nanotube layers. The method involves the aerosol thermolysis of toluene-ferrocene-cobaltocene solutions in inert atmospheres. The materials have been carefully characterized using state-of-the-art high-resolution transmission electron microscopy (HRTEM), electron-energy-loss spectroscopy (EELS), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), electron diffraction, HREELS-STM elemental mapping, X-ray powder diffraction, and SQUID magnetometry. We noted that the formation of FeCo alloys occurs at relatively low pyrolytic temperatures (e.g., 650-750 degrees C). These single-crystal nanowires, which have not been reported hitherto, always exhibit the FeCo (110) plane parallel to the carbon nanotube axis. The FeCo nanomaterials have shown large coercive fields at room temperature (e.g., 900 Oe). We envisage that these aligned ferromagnetic nanowires could be used in the fabrication of high-density magnetic storage devices and magnetic composites.

Ascariasis in children and the response to hexylresorcinol

1) A group of 347 children were observed for ascariasis in the Childrens Department of the North General Hospital2) Expulsion of ascaris and recurrent abdominal pain were the most common complaints on admission3) Children under four years comprised the most infested group. Sex had no bearing on the incidence of ascariasis4) Twelve patients presenting manifestations of acute abdomen were studied. All were over five years of age. Only one was operated on, but he was given hexylresorcinol treatment postoperatively. The other eleven cases were treated conservatively, and they were given hexylresorcinol therapy5) Of the 331 cases treated, 75.8% expelled ascaris, and, in most of them, this occurred 24 hours after administration of the crystoids. Most of them expelled less than ten ascaris immediately after therapy; but thirteen passed countless ascaris, and seven passed balls of worms6) Only 6 cases showed some untoward effects, of which first-degree burns of the buccal nucosa was the most common. All these, however, were very mild and transient. (Summary)