Dyrk1A is dynamically expressed on subsets of motor neurons and in the neuromuscular junction: possible role in Down syndrome

Individuals with Down syndrome (DS) present important motor deficits that derive from altered motor development of infants and young children. DYRK1A, a candidate gene for DS abnormalities has been implicated in motor function due to its expression in motor nuclei in the adult brain, and its overexpression in DS mouse models leads to hyperactivity and altered motor learning. However, its precise role in the adult motor system, or its possible involvement in postnatal locomotor development has not yet been clarified. During the postnatal period we observed time-specific expression of Dyrk1A in discrete subsets of brainstem nuclei and spinal cord motor neurons. Interestingly, we describe for the first time the presence of Dyrk1A in the presynaptic terminal of the neuromuscular junctions and its axonal transport from the facial nucleus, suggesting a function for Dyrk1A in these structures. Relevant to DS, Dyrk1A overexpression in transgenic mice (TgDyrk1A) produces motor developmental alterations possibly contributing to DS motor phenotypes and modifies the numbers of motor cholinergic neurons, suggesting that the kinase may have a role in the development of the brainstem and spinal cord motor system.

Graphoepitaxy of CeO2 on MgO and its application to the fabrication of 45° grain boundary Josephson junctions of YBa2Cu3O7-x

We communicate a detailed study of the epitaxial growth of CeO2 on MgO. The key feature of the growth is the dependence of the in¿plane orientation of the CeO2 epitaxial layer on the MgO surface morphology. Atomic force microscopic (AFM) measurements, x¿ray analyses, as well as high¿resolution transmission electron microscopy (HRTEM) investigations reveal that on rough substrates a cube¿on¿cube growth of CeO2 on MgO occurs while on smooth substrates the CeO2 unit cell is rotated around the surface normal by 45° with respect to the MgO unit cell when the deposition rate is low (~0.3 Å/s) during the first stages of growth. This growth mechanism can be used for a defined fabrication of 45° grain boundaries in the CeO2 layer by controlling the surface roughness of the MgO substrate. This report demonstrates that these 45° grain boundaries may be used to fabricate YBa2Cu3O7¿x Josephson junctions.

SrRuO3/SrTiO3/SrRuO3 heterostructures for magnetic tunnel junctions

We report on the growth and characterization of SrRuO3 single layers and SrRuO3/SrTiO3/SrRuO3 heterostructures grown on SrTiO3(100) substrates. The thickness dependence of the coercivity was determined for these single layers. Heterostructures with barrier thickness tb=1, 2.5, and 4 nm were fabricated, with electrodes having thickness ranging from 10 to 100 nm. The hysteresis loops of heterostructures with tb=2.5¿nm, 4 nm reveal uncoupled magnetic switching of the electrodes. Therefore, these heterostructures can be used for the fabrication of magnetic tunneling junctions.

Finite energy Dirac-Born-Infeld monopoles and string junctions

It is shown that the world volume field theory of a single D3-brane in a supergravity D3-brane background admits finite energy, and non-singular, Abelian monopoles and dyons preserving 1/2 or 1/4 of the N=4 supersymmetry and saturating a Bogomolnyi-type bound. The 1/4 supersymmetric solitons provide a world volume realization of string-junction dyons. We also discuss the dual M-theory realization of the 1/2 supersymmetric dyons as finite tension self-dual strings on the M5-brane, and of the 1/4 supersymmetric dyons as their intersections.

Plan integral de enfermería para la atención domiciliaria de pacientes con enfermedad neuromuscular e insuficiencia respiratoria

Las enfermedades neuromuscualres son enfermedades neurológicas, de naturaleza progresiva, normalmente hereditarias cuya principal característica clínica es la debilidad muscular. Dentro de las enfermedades que causan problemas respiratorios, existen una gran variedad de enfermedades neuromusculares que comprometen la función respiratoria, las cuales pueden dividirse en enfermedades neuromusculares neuropaticas y miopáticas, además de poder clasificarlas según la evolución. Las ENM pueden comprometer el sistema respiratorio condicionando morbilidad respiratoria de intensidad y precocidad variable dependiendo del grado de afección de los músculos respiratorios y deglutorios, así como de otros factores como el estado nutricional o la capacidad de deambulación, todos ellos factores que pueden ser incluidos dentro de un programa de enfermería de atención a domicilio.

Large Magnetoresistance in Fe/MgO/FeCo(001) Epitaxial Tunnel-Junctions on GaAs(001).

We present tunneling experiments on Fe~001!/MgO~20 Å!/FeCo~001! single-crystal epitaxial junctions of high quality grown by sputtering and laser ablation. Tunnel magnetoresistance measurements give 60% at 30 K, to be compared with 13% obtained recently on ~001!-oriented Fe/amorphous-Al2O3 /FeCo tunnel junctions. This difference demonstrates that the spin polarization of tunneling electrons is not directly related to the density of states of the free metal surface Fe~001! in this case but depends on the actual electronic structure of the entire electrode/barrier system.

Fast generation of spin-squeezed states in bosonic Josephson junctions

We describe methods for the fast production of highly coherent-spin-squeezed many-body states in bosonic Josephson junctions. We start from the known mapping of the two-site Bose-Hubbard (BH) Hamiltonian to that of a single effective particle evolving according to a Schrödinger-like equation in Fock space. Since, for repulsive interactions, the effective potential in Fock space is nearly parabolic, we extend recently derived protocols for shortcuts to adiabatic evolution in harmonic potentials to the many-body BH Hamiltonian. A comparison with current experiments shows that our methods allow for an important reduction in the preparation times of highly squeezed spin states.

Miopatía y polineuropatía en el paciente crítico. Estudio PEC: parálisis del enfermo crítico

Alguns pacients ingressats en la Unitat de Cures Intensives (UCI) desenvolupen una debilitat muscular en grau variable que pot arribar fins a la tetraparesia o tretraplejia. Aquesta condició és deguda a una disfunció neuromuscular perifèrica. No existeix consens internacional per al diagnòstic. En aquest treball s'estudien, de manera prospectiva, les alteracions en l'electromiograma i la seva correlació amb l'anatomia patològica del múscul com a mètode diagnòstic de miopatia i/o neuropatia del pacient crític. A més s'avaluen diversos factors predisponents i pronòstics, conseqüències d'aquesta malaltia i el seu moment d'inici.

Intraovarian sperm storage in Helicolenus dactylopterus dactylopterus fertilitzation, crypt formation and maintenance of stored sperm

The females of the bluemouth rockfish, Helicolenus dactylopterus dactylopterus (DelaRoche, 1809), store sperm within their ovaries for periods of up to 10 months. Twenty six females with standard lengths between 152 and 257 mm and six males with standard lengths between 253 and 209 mm were caught storage crypts with stored spermatozoa and to describe their evolution over the year. After internal fertilization and once sperm reaches the ovary, a crypt forms probably by an epithelial inclusion at the base of the lamellae of one or several spermatozoa groups that are floating freely in the interlamellar space of the ovarian lumen. Stored spermatozoa have a large cytoplasm bag surrounding their heads. This bag could serve as a nutritive reservoir during the long storage period. Many desmosonal and tight junctions between the crypt cells ensure tha male sex cells are protected against the female immune system

Podocalyxin is a novel polysialylated neural adhesion protein with multiple roles in neural development and synapse formation

Neural development and plasticity are regulated by neural adhesion proteins, including the polysialylated form of NCAM (PSA-NCAM). Podocalyxin (PC) is a renal PSA-containing protein that has been reported to function as an anti-adhesin in kidney podocytes. Here we show that PC is widely expressed in neurons during neural development. Neural PC interacts with the ERM protein family, and with NHERF1/2 and RhoA/G. Experiments in vitro and phenotypic analyses of podxl-deficient mice indicate that PC is involved in neurite growth, branching and axonal fasciculation, and that PC loss-of-function reduces the number of synapses in the CNS and in the neuromuscular system. We also show that whereas some of the brain PC functions require PSA, others depend on PC per se. Our results show that PC, the second highly sialylated neural adhesion protein, plays multiple roles in neural development.

Temporal changes in the expression and distribution of adhesion molecules during liver development and regeneration

We have compared by immunocytochemistry and immunoblotting the expression and distribution of adhesion molecules participating in cell-matrix and cell-cell interactions during embryonic development and regeneration of rat liver. Fibronectin and the fibronectin receptor, integrin alpha 5 beta 1, were distributed pericellularly and expressed at a steady level during development from the 16th day of gestation and in neonate and adult liver. AGp110, a nonintegrin fibronectin receptor was first detected on the 17th day of gestation in a similar, nonpolarized distribution on parenchymal cell surfaces. At that stage of development haemopoiesis is at a peak in rat liver and fibronectin and receptors alpha 5 beta 1 and AGp110 were prominent on the surface of blood cell precursors. During the last 2 d of gestation (20th and 21st day) hepatocytes assembled around lumina. AGp110 was initially depolarized on the surface of these acinar cells but then confined to the lumen and to newly-formed bile canaliculi. At birth, a marked increase occurred in the canalicular expression of AGp110 and in the branching of the canalicular network. Simultaneously, there was enhanced expression of ZO-1, a protein component of tight junctions. On the second day postpartum, presence of AGp110 and of protein constituents of desmosomes and intermediate junctions, DGI and E-cadherin, respectively, was notably enhanced in cellular fractions insoluble in nonionic detergents, presumably signifying linkage of AGp110 with the cytoskeleton and assembly of desmosomal and intermediate junctions. During liver regeneration after partial hepatectomy, AGp110 remained confined to apical surfaces, indicating a preservation of basic polarity in parenchymal cells. A decrease in the extent and continuity of the canalicular network occurred in proliferating parenchyma, starting 24 h after resection in areas close to the terminal afferent blood supply of portal veins and spreading to the rest of the liver within the next 24 h. Distinct acinar structures, similar to the ones in prenatal liver, appeared at 72 h after hepatectomy. Restoration of the normal branching of the biliary tree commenced at 72 h. At 7 d postoperatively acinar formation declined and one-cell-thick hepatic plates, as in normal liver, were observed.

Structural and functional characterization of (110)-oriented epitaxial La2/3Ca1/3MnO3 electrodes and SrTiO3 tunnel barriers

La2/3Ca1/3MnO3 (LCMO) films have been deposited on (110)-oriented SrTiO3 (STO) substrates. X-ray diffraction and high-resolution electron microscopy reveal that the (110) LCMO films are epitaxial and anisotropically in-plane strained, with higher relaxation along the [1¿10] direction than along the [001] direction; x-ray absorption spectroscopy data signaled the existence of a single intermediate Mn3+/4+ 3d-state at the film surface. Their magnetic properties are compared to those of (001) LCMO films grown simultaneously on (001) STO substrates It is found that (110) LCMO films present a higher Curie temperature (TC) and a weaker decay of magnetization when approaching TC than their (001) LCMO counterparts. These improved films have been subsequently covered by nanometric STO layers. Conducting atomic-force experiments have shown that STO layers, as thin as 0.8 nm, grown on top of the (110) LCMO electrode, display good insulating properties. We will show that the electric conductance across (110) STO layers, exponentially depending on the barrier thickness, is tunnel-like. The barrier height in STO (110) is found to be similar to that of STO (001). These results show that the (110) LCMO electrodes can be better electrodes than (001) LCMO for magnetic tunnel junctions, and that (110) STO are suitable insulating barriers.