657 research outputs found

    Resource utilization of microalgae from biological soil crusts::biodiesel production associated with desertification control

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    With the continuing consumption of resources and increasingly prominent environmental issues, microalgal resource utilization has received extensive attention. In this study, based on the microalgal investigation in desert biological soil crusts (BSCs) using pyrosequencing technology, the cultivated crust microalgae were further isolated in order to obtain high quality microalgae for resource utilization. The results showed that with crust development and succession, microalgal diversity gradually decreased, including the number of operational taxonomic units (OTUs) and genus, although Microcokus always was the dominant genera. Pyrosequencing obtained 630 OTUs of cyanobacteria, 25 OTUs of green algae and 9 OTUs of diatom; however, part of cultivated microalgae still could not yet be detected due to the DNA extraction preferences and errors caused by PCR amplification. After isolation, four strains were purified and cultivated, including two filamentous cyanobacteria Microcoleus vaginatus BSC-06 and Scytonema javanicum BSC-39, and two unicellular green algae Chlorella sp. BSC-24 and Monoraphidium dybowskii BSC-81. The two green algae grew fast (> 250 mg L-1 d(-1)), and achieved high lipid productivity up to 75-85 mg L-1 d(-1), with lipid content of 28.7-39.0%, thus was considered as promising feedstock for biodiesel production. In addition, the two crust cyanobacteria could be used to construct artificial cyanobacterial soil crusts in desertification control, although their biomass accumulation was not as high as that in the green algae. Ultimately, combining biodiesel production with desertification control would not only improve desert environments, but also provide ideal places for the local microalgal resource exploitation, further promoting desert socioeconomic development

    Ischemic Stroke in Pontine and Corona Radiata: Location Specific Impairment of Neural Network Investigated With Resting State fMRI

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    Objective: This study aims to investigate location-specific functional remodeling following ischemic stroke in pons and corona radiata.Methods: This study was approved by the local Institutional Review Board. Written consent was obtained from each of the participants prior to the MRI examination. Thirty six subjects with first ever acute ischemic stroke in pons (PS, n = 15, aged 62.8 ± 11.01 years) or corona radiata (CRS, n = 21, aged 59.33 ± 13.84 years) as well as 30 age and sex matched healthy controls (HC, n = 30, aged 60 ± 6.43 years) were examined with resting state functional magnetic resonance imaging (rs-fMRI). Regional homogeneity (ReHo) and degree centrality (DC) were calculated using a voxel-based approach. Intergroup differences in ReHo and DC were explored using a permutation test with a threshold-free cluster enhancement (PT TFCE, number of permutations = 1,000, family-wise error rate (FWER) < 0.05).Results: ReHo and DC alterations were identified in distributed anatomies for both PS and CRS groups. DC mainly increased in the bilateral anterior and posterior cingulate cortex, the inferior frontal-orbital gyrus, and decreased in the bilateral cuneus, calcarine, and the precuneus, while ReHo mainly decreased in the precentral and the postcentral gyri, inferior parietal lobules, precuneus, posterior cingulate cortex, and the superior occipital gyrus. PS and CRS groups were not significantly different in ReHo or DC (FWER > 0.05).Conclusions: Focal ischemic stroke in pons or corona radiata leads to extensive alterations in the functional network centrality. IS-induced network remodeling is more anatomy-specific than pathway-specific, which may underpin the clinicotopographical profiles during the disease dynamic. Approaches targeting neural pathway and functional connectivity may shed light on a better characterization and management innovation of ischemic stroke

    Fabrication and magnetic properties of Sm2Co17 and Sm2Co17/Fe7Co3 magnetic nanowires via AAO templates

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    AbstractThe Sm2Co17 single-phase and Sm2Co17/Fe7Co3 double-phase nanowire arrays with smaller diameter (around 50nm) have been fabricated into the anodic aluminum oxide (AAO) templates by direct-current electrodeposition. The crystal structure and micrograph of these nanowire arrays were characterized by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy (TEM). It is found that the as-deposited Sm2Co17 nanowires have the amorphous microstructure. The magnetic hysteresis loops obtained by vibrating sample magnetometer (VSM) show that the easily magnetized direction of the Sm2Co17 single-phase and Sm2Co17/Fe7Co3 double-phase nanowire arrays is parallel to the nanowire arrays and the exchange coupling interaction in nanocomposite Sm2Co17/Fe7Co3 is discussed. The study of the Sm2Co17 single-phase and Sm2Co17/Fe7Co3 double-phase nanowires with small diameter may open up new opportunities for the design and control of nanostructures such as the fabrication of magnetic recording devices

    Preparation and Characterization of Mesoporous Zirconia Made by Using a Poly (methyl methacrylate) Template

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    Superfine powders of poly (methyl methacrylate) (PMMA) have been prepared by means of an emulsion polymerization method. These have been used as templates in the synthesis of tetragonal phase mesoporous zirconia by the sol–gel method, using zirconium oxychloride and oxalic acid as raw materials. The products have been characterized by infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, N2adsorption-desorption isotherms, and pore size distribution. The results indicate that the average pore size was found to be 3.7 nm
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