Full polarization chaos in a pump-polarization modulated isotropic cavity laser

We study the dynamic behavior of an optically pumped J = 0 → J = 1 → J = 0 laser operating with an isotropic ring cavity and a linearly polarized pump field whose direction of polarization is modulated by the sinusoidal law θ(t) = m sin Ωt. Modulation frequencies Ω of the same order of magnitude as the transverse relaxation rate of the laser transition are considered here. At large enough modulation amplitudes, and for a detuned cavity, we obtain fully developed polarization chaos, which affects both the ellipticity and the orientation of the polarization ellipse as well as the laser intensity

Mutations in the EXT1 and EXT2 genes in Spanish patients with multiple osteochondromas

Multiple osteochondromas is an autosomal dominant skeletal disorder characterized by the formation of multiple cartilage-capped tumours. Two causal genes have been identified, EXT1 and EXT2, which account for 65% and 30% of cases, respectively. We have undertaken a mutation analysis of the EXT1 and EXT2 genes in 39 unrelated Spanish patients, most of them with moderate phenotype, and looked for genotype-phenotype correlations. We found the mutant allele in 37 patients, 29 in EXT1 and 8 in EXT2. Five of the EXT1 mutations were deletions identified by MLPA. Two cases of mosaicism were documented. We detected a lower number of exostoses in patients with missense mutation versus other kinds of mutations. In conclusion, we found a mutation in EXT1 or in EXT2 in 95% of the Spanish patients. Eighteen of the mutations were novel.Fil: Sarrión, P.. Universidad de Barcelona; EspañaFil: Sangorrin, A.. Hospital Sant Joan de Déu; EspañaFil: Urreizti, R.. Universidad de Barcelona; EspañaFil: Delgado, María Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Artuch, R.. Hospital Sant Joan de Déu; EspañaFil: Martorell, L.. Hospital Sant Joan de Déu; EspañaFil: Armstrong, J.. Hospital Sant Joan de Déu; EspañaFil: Anton, J.. Hospital Sant Joan de Déu; EspañaFil: Torner, F.. Hospital Sant Joan de Déu; EspañaFil: Vilaseca, M. A.. Hospital Sant Joan de Déu; EspañaFil: Nevado, J.. Hospital Universitario La Paz; EspañaFil: Lapunzina, P.. Hospital Universitario La Paz; EspañaFil: Asteggiano, Carla Gabriela. Universidad Nacional de Córdoba; Argentina. Universidad Católica de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Balcells, S.. Universidad de Barcelona; EspañaFil: Grinberg, D.. Universidad de Barcelona; Españ

Valorization of Hemp Core Residues: Impact of NaOH Treatment on the Flexural Strength of PP Composites and Intrinsic Flexural Strength of Hemp Core Fibers

Hemp core is a lignocellulosic residue in the production chain of hemp strands. Huge amounts of hemp core are gathered annually in Europe (43,000 tons) with no major application end. Such lignocellulosic wastes have potential as filling or reinforcing material to replace synthetic fibers and wood fibers in polymer composites. In this study, hemp core biomass was treated under different NaOH concentrations and then defibrated by means of Sprout Waldron equipment to obtain single fibers. Polypropylene matrix was reinforced up to 50 wt.% and the resulting hemp core fibers and the flexural properties were investigated. The results show that the flexural strength of composites increased with the intensity of NaOH treatment. The effect of NaOH was attributed to the removal of extractives and lignin in the fiber cell wall leading to improved interfacial adhesion characteristics. Besides, a methodology was established for the estimation of the intrinsic flexural strength of hemp core fibers. The intrinsic flexural strength of hemp core fibers was calculated to be 940 MPa for fibers treated at 10 wt.% of NaOH. In addition, a relationship between the lignin content and the intrinsic strength of the fibers was established

Undetectable Levels of CSF Amyloid-β Peptide in a Patient with 17β-Hydroxysteroid Dehydrogenase Deficiency

17β-hydroxysteroid dehydrogenase 10 (HSD10) deficiency is a rare X-linked inborn error of isoleucine catabolism. Although this protein has been genetically implicated in Alzheimer's disease pathogenesis, studies of amyloid-β peptide (Aβ) in patients with HSD10 deficiency have not been previously reported. We found, in a severely affected child with HSD10 deficiency, undetectable levels of Aβ in the cerebrospinal fluid, together with low expression of brain-derived neurotrophic factor, α-synuclein, and serotonin metabolites. Confirmation of these findings in other patients would help elucidating mechanisms of synaptic dysfunction in this disease, and highlight the role of Aβ in both early and late periods of life

Homocistinuria y Acidemia Metilmalónica (CbIC) de evolución fatal en un recién nacido

La forma CblC de la Acidemia Metilmalónica (AMMC CbIC) es un error congénito del metabolismo intracelular de la cobalamina. Los síntomas clínicos consisten en descompensación neurológica y síntomas sistémicos. Describimos la evolución clínica y bioquímica en una paciente con inicio neonatal del defecto CblC. Recién nacido a termino, mujer, con peso al nacer de 2290 g. A los pocos día de vida presentó hipotonía, hipoactividad y succión dificultosa. Alos 13 días de vida se ingresó en UCIN presentando letargia, hipotonía, hipotermia y signos de afectación neurológica de tronco encefálico, además hiperlactacidemia y alteraciones del recuento celular. La RNM junto con los síntomas clínicos nos surgirieron una patología mitocondrial. Los ácidos orgánicos mostraron un importante aumento del ácido metilmalónico con homocistinemia y homocistinuria, sospechándose un defecto del metabolismo de la cobalamina que se comprobó in vitro. En el estudio mutacional se confirmó el diagnostico de AMM CbIC. A pesar de una buena respuesta bioquímica al tratamiento con cobalamina la paciente mantuvo un deterioro neurológico progresivo con éxitus a los 2 meses de vida. Se concluye que la AMMC, variante CblC, se puede presentar con retraso en el desarollo, lactacidemia y alteración en los parámetros hematológicos. A pesar de la normalización de los parámetros bioquímicos presentó una progresión de la enfermedad que la condujo al éxitus. Se especula la posibilidad de que existan otros factores fisiopatológicos que influyen en una mala evolución.The CblC form of methylmalonic acidemia with homocistinuria (MMA CblC) is a rare condition which results from impaired biosynthesis of methylcobalamin and adenosylcobalamin. The clinical phenotype implies neurological decompensation and systemic symptoms. We describe the clinical course and biochemical evolution of a girl with neonatal onset of the CblC variant. The female patient was delivered at term and weighed 2290 gr. The mother noticed hypotonia, hypoactivity and lack of sucking from very early on. At the 13 th day of life the patient was admitted to our hospital at the NICU. Lethargy, hypotonia, hipothermia, central ataxic breathing were the main symptoms. Initial blood profile pointed moderate hyperlactacidemia and alterations of blood cell count. RMN and the clinical profile suggested a mitochondrial disease. The metabolic profile, showed methylmalonic aciduria, with homocystinemia and homocystinuria suggesting a intracellular defect of cobalamin metabolism. The diagnosis of a MMA CbIC variant was confirmed by the propionate test in vitro and the genetic study. After treatment with cobalamin, levels of methylmalonic acid and homocysteine normalized, but the patient suffered progressive neurological deterioration with secondary multiorgan failure and death at two months of age. We conclude that Methylmalonic Aciduria with combined homocystinuria, CblC variant, may present with developmental delay, minor dysmorphology, moderate hyperlactacidemia and alteration of hematologic parameters. In spite of a normalization of biochemical parameters the disease led to a fatal outcome. We therefore think that in presence of a dysfunction of intracellular cobalamin, other physiological alterations leading to a fatal evolution might be possible

The Gcn4 transcription factor reduces protein synthesis capacity and extends yeast lifespan

In Saccharomyces cerevisiae, deletion of large ribosomal subunit protein-encoding genes increases the replicative lifespan in a Gcn4-dependent manner. However, how Gcn4, a key transcriptional activator of amino acid biosynthesis genes, increases lifespan, is unknown. Here we show that Gcn4 acts as a repressor of protein synthesis. By analyzing the messenger RNA and protein abundance, ribosome occupancy and protein synthesis rate in various yeast strains, we demonstrate that Gcn4 is sufficient to reduce protein synthesis and increase yeast lifespan. Chromatin immunoprecipitation reveals Gcn4 binding not only at genes that are activated, but also at genes, some encoding ribosomal proteins, that are repressed upon Gcn4 overexpression. The promoters of repressed genes contain Rap1 binding motifs. Our data suggest that Gcn4 is a central regulator of protein synthesis under multiple perturbations, including ribosomal protein gene deletions, calorie restriction, and rapamycin treatment, and provide an explanation for its role in longevity and stress response

Sub-Doppler cooling of three-level A Atoms in space-shifted standing light waves

We present an investigation of an alternative mechanism for sub-Doppler cooling of atoms, based on coherent population transfer in three-level LAMBDA systems. The mechanism considered is that of a LAMBDA atom interacting with two standing light waves with a mutual spatial phase shift phi not-equal 0. The spatial dependence of the level populations of the LAMBDA atom for different values of phi is presented. For phi not-equal 0, this clearly demonstrates coherent population transfer in an atom with transverse motion along the space-shifted nodes and antinodes of the two standing waves. We show that this allows translational temperatures well below the Doppler limit T(D) = hgammaBAR/k(B) to be achieved

Self-assembled trityl radical capsules implications for dynamic nuclear polarization

A new class of guest-induced, bi-radical self-assembled organic capsules is reported. They are formed by the inclusion of a tetramethylammonium (TMA) cation between two monomers of the stable trityl radical OX63. OX63 is extensively used in dissolution dynamic nuclear polarization (DNP) where it leads to NMR sensitivity enhancements of several orders of magnitude. The supramolecular properties of OX63 have a strong impact on its DNP properties. An especially relevant case is the polarization of choline-containing metabolites, where complex formation between choline and OX63 results in faster relaxation