Size and emission wavelength control of InAs/InP quantum wires

For a certain heteroepitaxial system, the optical properties of self-assembled nanostructures basically depend on their size. In this work, we have studied different ways to modify the height of InAs/InP quantum wires (QWrs) in order to change the photoluminescence emission wavelength. One procedure consists of changing the QWr size by varying the amount of InAs deposited. The other two methods explored rely on the control of As/P exchange process, in one case during growth of InAs on InP for QWr formation and in the other case during growth of InP on InAs for QWr capping. The combination of the three approaches provides a fine tuning of QWr emission wavelength between 1.2 and 1.9 μm at room [email protected]

Polarized laser light scattering applied to surface morphology characterization of epitaxial III–V semiconductor layers

11 pages.-- PACS: 68.35.Bs; 81.05.Ea; 81.15.Hi; 78.35.+c; 78.66.FdIn this paper, we analyze typical morphologies of epitaxial III–V semiconductor layers by using a polarized laser light scattering technique. Crosshatched topographies, which are developed during heteroepitaxial growth, are studied. A sample with an intentionally high density of oval defects is also explored to establish how the laser light scattering pattern is affected by the presence of these defects, which are unavoidable in the epitaxial layers grown by molecular beam epitaxy. The former topographies produce a scattered light pattern that is highly anisotropic, with the intensity concentrated along two preferential directions; the latter defects give rise to a fairly isotropic pattern. Employing a perturbation-theoretical model, whose applicability and consistency are explicitly demonstrated by our results, the surface power spectral density is retrieved from the angle-resolved light scattering experimental data. For the samples exhibiting crosshatched topography, the scattering measurements provide information that allows us to model the roughness of the surface in terms of two quasi-one-dimensional, anisotropic components, and one two-dimensional, isotropic, long-range background. The root mean square heights and the typical lateral distances between ridges are obtained in quantitative agreement with the values extracted from the atomic force microscopy measurements. For the sample presenting oval defects, we consider their contribution to the surface power spectral density by means of a simple model of randomly distributed particles on a surface, and we compare the resulting power spectral density with typical behavior found in the literature for good-morphology GaAs layers. With the help of the ex situ information thus obtained, we also discuss the implementation of the light scattering technique for in situ monitoring during epitaxial growth.The authors wish to acknowledge the Spanish CICYT for financial support under Project No. TIC96-1020-C02. M.U.G. thanks the Consejería de Educación y Cultura de la Comunidad de Madrid for financial support. J.A.S.-G. acknowledges financial support from the Spanish DGESIC Grant No. PB97-1221.Spanish CICYTConsejería de Educación y Cultura de la Comunidad de MadridPeer reviewe

Cardioprotection of benzolamide in a regional ischemia model: Role of ENOS/NO

Background: Recent studies from our laboratory show the cardioprotective action of benzolamide (BZ, carbonic anhydrase inhibitor) against ischemia-reperfusion injury. However, the mechanisms involved have not been fully elucidated. Objective: To examine the participation of the endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) in the effects of BZ in a model of regional ischemia.Methods: Isolated rat hearts perfused by Langendorff technique were submitted to 40 min of coronary artery occlusion followed by 60 min of reperfusion (IC). Other hearts received BZ during the first 10 min of reperfusion in absence or presence of L-NAME, NOS inhibitor. The infarct size (IS) and the post-ischemic recovery of myocardial function were measured. Oxidative/nitrosative damage were assessed by reduced glutathione (GSH) content, thiobarbituric acid reactivesubstances (TBARS) and 3-nitrotyrosine levels. The expression of phosphorylated forms of Akt, p38MAPK and eNOS, and the concentration of inducible nitric oxide synthase (iNOS) were also determined. Results: BZ significantly decreased IS (6.2 ± 0.5% vs. 34 ± 4%), improved postischemic contractility, preserved GSH levels and diminished TBARS and 3-nitrotyrosine. In IC hearts, P-Akt, P-p38MAPK and P-eNOS decreased and iNOS increased. After BZ addition the levels of P-kinases and P-eNOS increased and iNOS decreased. Except for P-Akt, P-p38MAPK and iNOS, the effects of BZ were abolished by L-NAME. Conclusions: Our data demonstrate that the treatment with BZ at the onset of reperfusion was effective to reduce cell death, contractile dysfunction and oxidative/nitrosative damage produced by coronary artery occlusion. These BZmediated beneficial actions appear mediated by eNOS/NO-dependent pathways.Fil: González Arbeláez, Luisa Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Ciocci Pardo, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Swenson, Eric R.. University of Washington; Estados UnidosFil: Álvarez, Bernardo V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Mosca, Susana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Fantinelli, Juliana Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; Argentin

Cardioprotection of benzolamide in a regional ischemia model: Role of eNOS/NO

Background: Recent studies from our laboratory show the cardioprotective action of benzolamide (BZ, carbonic anhydrase inhibitor) against ischemia-reperfusion injury. However, the mechanisms involved have not been fully elucidated. Objective: To examine the participation of the endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) in the effects of BZ in a model of regional ischemia.Methods: Isolated rat hearts perfused by Langendorff technique were submitted to 40 min of coronary artery occlusion followed by 60 min of reperfusion (IC). Other hearts received BZ during the first 10 min of reperfusion in absence or presence of L-NAME, NOS inhibitor. The infarct size (IS) and the post-ischemic recovery of myocardial function were measured. Oxidative/nitrosative damage were assessed by reduced glutathione (GSH) content, thiobarbituric acid reactivesubstances (TBARS) and 3-nitrotyrosine levels. The expression of phosphorylated forms of Akt, p38MAPK and eNOS, and the concentration of inducible nitric oxide synthase (iNOS) were also determined. Results: BZ significantly decreased IS (6.2 ± 0.5% vs. 34 ± 4%), improved postischemic contractility, preserved GSH levels and diminished TBARS and 3-nitrotyrosine. In IC hearts, P-Akt, P-p38MAPK and P-eNOS decreased and iNOS increased. After BZ addition the levels of P-kinases and P-eNOS increased and iNOS decreased. Except for P-Akt, P-p38MAPK and iNOS, the effects of BZ were abolished by L-NAME. Conclusions: Our data demonstrate that the treatment with BZ at the onset of reperfusion was effective to reduce cell death, contractile dysfunction and oxidative/nitrosative damage produced by coronary artery occlusion. These BZmediated beneficial actions appear mediated by eNOS/NO-dependent pathways.Centro de Investigaciones Cardiovasculare

Myocardial and mitochondrial effects of the anhydrase carbonic inhibitor ethoxzolamide in ischemia-reperfusion

We have previously demonstrated that inhibition of extracellularly oriented carbonic anhydrase (CA) isoforms protects the myocardium against ischemia-reperfusion injury. In this study, our aim was to assess the possible further contribution of CA intracellular isoforms examining the actions of the highly diffusible cell membrane permeant inhibitor of CA, ethoxzolamide (ETZ). Isolated rat hearts, after 20 min of stabilization, were assigned to the following groups: (1) Nonischemic control: 90 min of perfusion; (2) Ischemic control: 30 min of global ischemia and 60 min of reperfusion (R); and (3) ETZ: ETZ at a concentration of 100 μM was administered for 10 min before the onset of ischemia and then during the first 10 min of reperfusion. In additional groups, ETZ was administered in the presence of SB202190 (SB, a p38MAPK inhibitor) or chelerythrine (Chel, a protein kinase C [PKC] inhibitor). Infarct size, myocardial function, and the expression of phosphorylated forms of p38MAPK, PKCε, HSP27, and Drp1, and calcineurin Aβ content were assessed. In isolated mitochondria, the Ca2+ response, Ca2+ retention capacity, and membrane potential were measured. ETZ decreased infarct size by 60%, improved postischemic recovery of myocardial contractile and diastolic relaxation increased P-p38MAPK, P-PKCε, P-HSP27, and P-Drp1 expression, decreased calcineurin content, and normalized calcium and membrane potential parameters measured in isolated mitochondria. These effects were significantly attenuated when ETZ was administered in the presence of SB or Chel. These data show that ETZ protects the myocardium and mitochondria against ischemia-reperfusion injury through p38MAPK- and PKCε-dependent pathways and reinforces the role of CA as a possible target in the management of acute cardiac ischemic diseases.Fil: Ciocci Pardo, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: González Arbeláez, Luisa Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Fantinelli, Juliana Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Álvarez, Bernardo V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Mosca, Susana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Swenson, Erik R.. Washington University in St. Louis; Estados Unido

Positive and negative regulation of carbon nanotube catalysts through encapsulation within macrocycles

One of the most attractive applications of carbon nanomaterials is as catalysts, due to their extreme surface-to-volume ratio. The substitution of C with heteroatoms (typically B and N as p- and n-dopants) has been explored to enhance their catalytic activity. Here we show that encapsulation within weakly doping macrocycles can be used to modify the catalytic properties of the nanotubes towards the reduction of nitroarenes, either enhancing it (n-doping) or slowing it down (p-doping). This artificial regulation strategy presents a unique combination of features found in the natural regulation of enzymes: binding of the effectors (the macrocycles) is noncovalent, yet stable thanks to the mechanical link, and their effect is remote, but not allosteric, since it does not affect the structure of the active site. By careful design of the macrocycles' structure, we expect that this strategy will contribute to overcome the major hurdles in SWNT-based catalysts: activity, aggregation, and specificity.Funding from the European Union (ERC-Starting Grant: 307609 (to E.M.P.)), MINECO (Grants: CTQ2014-60541-P (to E.M.P.), JdC-2015-23531 postdoctoral fellowship (to B.N.-O.)), and the Comunidad de Madrid (Grant: MAD2D-CM program S2013/MIT-3007 (to E.M.P.)) is gratefully acknowledged. IMDEA Nanociencia acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant SEV-2016-0686

Resistencia a biocidad en cepas de Salmonella SP. aisladas de huevo

Se ha estudiado la presencia de presuntas salmonelas en la superficie de huevos comerciales, y se ha determinado la sensibilidad a biocidas para la colección de cepas ensayadas. El porcentaje de muestras positivas osciló entre el 37% y el 43%. En algunas de las marcas comerciales analizadas no se logró aislar la bacteria en los huevos analizados, mientras que en los huevos de comercios pequeños o granjas se aisló en todas las muestras ensayadas. La mayoría de las cepas fueron inhibidas a una concentración del 0.1% de los biocidas cloruro de benzalconio, cetrimida, hexadecilpiridinio, hexaclorofeno, polihexametil biguanidio o P3 oxonia. Sin embargo, en algunos casos (cetrimida, polihexametil biguanidio o P3 oxonia ) se encontró un bajo porcentaje de cepas que requerían concentraciones de biocida de hasta diez veces superiores para su inhibición. El triclosan mostró una mayor eficacia, inhibiendo al 77% de las cepas a una concentración de 0.075%. Sin embargo, el resto de las cepas fueron muy tolerantes a este biocida, siendo necesaria una concentración del 1% para su inhibición. Los resultados de este estudio sugieren la existenciaWe have studied the presence of presumptive salmonellae in comercial eggs, and the biocide tolerance of isolates. Presumptive salmonellae were detected in some 37 to 43% of samples tested. Some comercial brands were free of the bacterium, but all eggs from local stores and farms tested positive. Most isolates were inhibited by 0.1% of the biocides benzalkonium chloride, cetrimide, hexadecylpyridinium chloride, hexachlorophene, polyhexamethylen biguanide and P3 oxonia. A small percentage of isolates required up to ten-fold higher biocide concentrations for inhibition (as in the case of cetrimide, polyhexamethylen biguanide and P3 oxonia). Triclosan was apparently more effective, inhibiting 77% of isolates at 0.075%. However, the remaining of isolates only were inhibited at 1% of the biocide. Results from this study suggest that a low percentage of the Salmonella population on egg surfaces can tolerate biocides

Early neuromodulation prevents the development of brain and behavioral abnormalities in a rodent model of schizophrenia

The notion that schizophrenia is a neurodevelopmental disorder in which neuropathologies evolve gradually over the developmental course indicates a potential therapeutic window during which pathophysiological processes may be modified to halt disease progression or reduce its severity. Here we used a neurodevelopmental maternal immune stimulation (MIS) rat model of schizophrenia to test whether early targeted modulatory intervention would affect schizophrenia’s neurodevelopmental course. We applied deep brain stimulation (DBS) or sham stimulation to the medial prefrontal cortex (mPFC) of adolescent MIS rats and respective controls, and investigated its behavioral, biochemical, brain-structural and -metabolic effects in adulthood. We found that mPFC-DBS successfully prevented the emergence of deficits in sensorimotor gating, attentional selectivity and executive function in adulthood, as well as the enlargement of lateral ventricle volumes and mal-development of dopaminergic and serotonergic transmission. These data suggest that the mPFC may be a valuable target for effective preventive treatments. This may have significant translational value, suggesting that targeting the mPFC before the onset of psychosis via less invasive neuromodulation approaches may be a viable preventive strategy.We thank Renate Winter, Doris Zschaber and Roselies Pickert for excellent technical assistance. This research was conducted under the EraNet Neuron framework (DBS_F20rat) and supported by the BMBF, Germany (B01EW1103, 01EE1403A), Fundación Mapfre, Comunidad de Madrid and the Ministry of Economy and Competitiveness ISCIII-FIS grants (PI14/00860, CPII/00005) co-financed by ERDF (FEDER) Funds from the European Commission, ‘A way of making Europe’, Spain (PI14/00860, CPII/00005, MV1500002), the CSO-MOH, Israel (3-8580) and the Canadian Institutes of Health Research, Canada (CIHR, 110068), and co-financed by the DFG, Germany (WI 2140/1-1/2; WI 2140/2-1).Publicad

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund