325 research outputs found

    Enhanced Eshelby twist on thin wurtzite InP nanowires and measurement of local crystal rotation

    Get PDF
    We have performed a detailed study of the lattice distortions of InP wurtzite nanowires containing an axial screw dislocation. Eshelby predicted that this kind of system should show a crystal rotation due to the dislocation induced torque. We have measured the twisting rate and the dislocation Burgers vector on individual wires, revealing that nanowires with a 10-nm radius have a twist up to 100% larger than estimated from elasticity theory. The strain induced by the deformation has a Mexican-hat-like geometry, which may create a tube-like potential well for carriers

    Galeorhinus galeus, Tope

    Get PDF
    Tope (Galeorhinus galeus) is a medium-sized (to 200 cm total length) bentho-pelagic shark, widespread in temperate waters in most oceans. It is present across the Northeast, Eastern Central, Southwest, and Southeast Atlantic, the Mediterranean Sea, the Eastern Indian, and across all of the Pacific, except in the Northwest Pacific. It occurs on continental shelves and upper to mid slopes from shallow inshore to well offshore to depths of 826 m, though most frequently to depths of 200 m. Genetic and tagging data support up to six separate subpopulations of Tope and while the species makes extensive movements within each of the subpopulations, there is no evidence of mixing between them. Tope has a particularly low biological productivity with a late age-at-maturity and triennial reproductive cycle. It is caught globally as target and bycatch in industrial and small-scale demersal and pelagic gillnet and longline fisheries, and to a lesser extent in trawl and hook-and-line fisheries. Tope is often retained for the meat and fins but is discarded or released in some areas, in line with regional management measures. Steep subpopulation and stock reductions of >80% over the past three generation lengths (79 years) have occurred in the Southwest Atlantic, southern Africa, and Australia. In the Northeast Atlantic, the subpopulation is estimated to have undergone a reduction of 76% over the past three generation lengths (79 years). The New Zealand stock is estimated to have undergone a reduction of 30?49% over the past three generation lengths (79 years). In the Northeast Pacific, a dramatic decline in the subpopulation occurred in the early 1940s, with no recovery until 1997?2004 when localized management led to a localized increase in abundance. The consistent steep subpopulation reductions across most of the analyzed subpopulations and stocks together with the lack of movement between the subpopulations are cause for serious concern. Management in Australia, probably aided by the immigration of large mature animals from New Zealand, appears to have stabilized that stock since 2000. The subpopulation in the Northeast Atlantic has been stable in recent years, possibly due to management measures, and there is some recovery in part of the Northeast Pacific. Release of this species is mandatory since 2011 off Canada. Release is mandatory in European Union waters for line-caught Tope. The global population is estimated to have undergone a reduction of 88% with the highest probability of >80% reduction over the last three generations (79 years) due to levels of exploitation, and Tope is assessed as Critically Endangered A2bd.Fil: Walker, T. I.. University of Melbourne; AustraliaFil: Rigby, C. L.. James Cook University; AustraliaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Ellis, J.. No especifíca;Fil: Kulka, D. W.. No especifíca;Fil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Herman, K.. Georgia Aquarium; Estados Unido

    New Histamine-Related Five-Membered N-Heterocycle Derivatives as Carbonic Anhydrase I Activators

    Get PDF
    A series of histamine (HST)-related compounds were synthesized and tested for their activating properties on five physiologically relevant human Carbonic Anhydrase (hCA) isoforms (I, II, Va, VII and XIII). The imidazole ring of HST was replaced with different 5-membered heterocycles and the length of the aliphatic chain was varied. For the most interesting compounds some modifications on the terminal amino group were also performed. The most sensitive isoform to activation was hCA I (K(A) values in the low micromolar range), but surprisingly none of the new compounds displayed activity on hCA II. Some derivatives (1, 3a and 22) displayed an interesting selectivity for activating hCA I over hCA II, Va, VII and XIII

    Effect of virtual reality rehabilitation on functional outcomes for return-to-work patients with Parkinson's disease: an umbrella review of systematic reviews

    Get PDF
    BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disease characterized by loss of substantia nigra neurons with deficiency of dopamine. The main symptoms are tremor, rigidity and bradykinesia. Rehabilitation has an important role in the treatment of this condition and virtual reality (VR) is one of the most recent tools. OBJECTIVE: The purpose of this umbrella review is to evaluate the effectiveness of VR systems on gait control for return to work in patients with PD. METHODS: The electronic search, for reviews and meta-analysis studies that investigated the effectiveness of VR on gait control in PD patients, was performed through December 2021 using the following databases: PubMed, Scopus, PEDro, and Google Scholar. Mesh terms used were: Job integration/reintegration OR return-to-work AND Parkinson's disease AND virtual reality OR exergame. No limit on the year of publication of the article was used. CONCLUSIONS: A total of 14 articles were included in our analysis. The included evidence shows a stride length improvement in patients treated with VR compared to conventional active treatments. No difference was found in walking speed. Also, the included articles show an improvement on various measures of balance, motor function and severity of PD motor symptoms. In addition, the literature shows an improvement in the quality of life and neuropsychiatric symptoms in patients undergoing VR rehabilitation training. RESULTS: he results of our study suggest that VR rehabilitation improves gait performance, particularly stride length, thus being able to provide an improvement in the quality of life and a more effective return to work training in patients with PD

    Optical phonon modes of wurtzite InP

    Get PDF
    Optical vibration modes of InP nanowires in the wurtzite phase were investigated by Raman scattering spectroscopy. The wires were grown along the [0001] axis by the vapor-liquid-solid method. The A1(TO), E2h, and E1(TO) phonon modes of the wurtzite symmetry were identified by using light linearly polarized along different directions in backscattering configuration. Additionally, forbidden longitudinal optical modes have also been observed. Furthermore, by applying an extended 11-parameter rigid-ion model, the complete dispersion relations of InP in the wurtzite phase have been calculated, showing a good agreement with the Raman experimental data
    • …
    corecore