993 research outputs found

    Effect of characteristics of (Sm,Ce)O2 powder on the fabrication and performance of anode-supported solid oxide fuel cells

    Get PDF
    Effect of characteristics of Sm0.2Ce0.8O1.9 (SDC) powder as a function of calcination temperature on the fabrication of dense and flat anode-supported SDC thin electrolyte cells has been studied. The results show that the calcination temperature has a significant effect on the particle size, degree of agglomeration, and sintering profiles of the SDC powder. The characteristics of SDC powders have a significant effect on the structure integrity and flatness of the SDC electrolyte film/anode substrate bilayer cells. The SDC electrolyte layer delaminates from the anode substrate for the SDC powder calcined at 600 °C and the bilayer cell concaves towards the SDC electrolyte layer for the SDC powder calcined at 800 °C. When the calcinations temperature increased to 1000 °C, strongly bonded SDC electrolyte film/anode substrate bilayer structures were achieved. An open-circuit voltage (OCV) of 0.82–0.84 V and maximum power density of ~1 W cm−2 were obtained at 600 °C using hydrogen as fuel and stationary air as the oxidant. The results indicate that the matching of the onset sintering temperature and maximum sintering rate temperature is most critical for the development of a dense and flat Ni/SDC supported SDC thin electrolyte cells for intermediate temperature solid oxide fuel cells

    Fabrication and characterization of PEEK/PEI multilayer composites

    Get PDF
    Polyetheretherketone (PEEK)/polyetherimide (PEI) blends (50/50, v/v) keeping the crystal phase of PEEK have been manufactured by alternate PEEK/PEI layer stacking. This strategy avoided the complete miscibility of both polymers, keeping layers of PEEK and PEI unmixed along the sample thickness, as well as promoting the formation of a smooth interfacial layer where PEEK and PEI were mixed. The properties of this interface after processing at molten state and different times was studied by DSC, DMA, and X-Ray synchrotron. These techniques allowed monitoring the evolution of glass transition, where isolated Tg’s for both pristine polymers were observed even after long processing time. PEEK crystallinity slightly decreased during manufacturing, whereas PEEK crystal parameters did not vary. These observations show that, although the interface—the zone where both polymers are mixed—grew, layers with pristine polymers remained even after prolonged processing time. The preservation of the PEEK crystallinity was also observed in the mechanical properties of the multilayer PEEK/PEI films, which were compared with pristine PEEK and PEI films. Multilayer samples processed for shorter times rendered higher young modulus, tensile strength, and strain at break.Ángel Alvaredo-Atienza gratefully acknowledges the Community of Madrid for financial support through the framework ‘Sistema Nacional de Garantía Juvenil’ fomented by the European Social Fund and the Youth Employment Initiative. SAXS/WAXS experiments were funded by the Diamond Light Source Synchrotron, (grant number SM20494). This work benefited from the use of the SasView application, originally developed under NSF award DMR-0520547. SasView contains code developed with funding from the European Union’s Horizon 2020 research and innovation programme under the SINE2020 project, grant agreement No 654000

    Entanglement detection via condition of quantum correlation

    Full text link
    We develop a novel necessary condition of quantum correlation. It is utilized to construct dd-level bipartite Bell-type inequality which is strongly resistant to noise and requires only analyses of O(d)O(d) measurement outcomes compared to the previous result O(d2)O(d^{2}). Remarkably, a connection between the arbitrary high-dimensional bipartite Bell-type inequality and entanglement witnesses is found. Through the necessary condition of quantum correlation, we propose that the witness operators to detect truly multipartite entanglement for a generalized Greenberger-Horne-Zeilinger (GHZ) state with two local measurement settings and a four-qubit singlet state with three settings. Moreover, we also propose the first robust entanglement witness to detect four-level tripartite GHZ state with only two local measurement settings

    Amino-functionalized mesoporous silica based polyethersulfone-polyvinylpyrrolidone composite membranes for elevated temperature proton exchange membrane fuel cells

    Get PDF
    It is important to find alternative membranes to the state-of-the-art polybenzimidazole based high temperature proton exchange membranes with high proton conductivity at elevated temperature but with simple synthesis procedures. In this work, inorganic-organic nanostructured hybrid membranes are developed based on a polyethersulfone-polyvinylpyrrolidone (PES-PVP) polymeric matrix with hollow mesoporous silica (HMS), amino-functionalized hollow mesoporous silica (NH2-HMS) and amino-functionalized mesoporous silica (NH2-meso-silica). The composite membranes show a significant increase in proton conductivity and a decrease in the activation energy for proton diffusion in comparison with the phosphoric acid (H3PO4, PA) doped PES-PVP membrane. And the composite membrane with NH2-HMS shows the best performance under the conditions in this study, achieving the highest proton conductivity of 1.52 × 10-1 S cm-1 and highest peak power density of 480 mW cm-2 at 180 °C under anhydrous conditions, which is 92.7% higher than that of the PA doped PES-PVP membrane at identical conditions. Such enhancement results from the facilitated proton transportation in the ordered mesoporous channels via the hydrogen bond between the -NH2 groups and H3PO4. The high water retention capability of silica materials with a hollow structure also contributes to the decrease of the activation of proton diffusion. Consequently, the results show promising potential of the NH2-HMS based PES-PVP composite membrane for the elevated temperature proton exchange membrane fuel cells

    (E)-N′-(2-Hydr­oxy-4-methoxy­benzyl­idene)isonicotinohydrazide monohydrate

    Get PDF
    The title compound, C14H13N3O3·H2O, was prepared by the reaction of 4-methoxy­salicylaldehyde and isonicotinohydrazide in ethanol. The Schiff base mol­ecule is not planar and has an E configuration with respect to the methyl­idene unit. The dihedral angle between the benzene and pyridine rings is 36.8 (2)°. In the mol­ecule there is an intra­molecular O—H⋯N hydrogen bond involving the hydroxyl substituent and the N atom of the 2-hydr­oxy-4-methoxy­benzyl­idene unit. In the crystal, the mol­ecules are linked through inter­molecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds, forming layers parallel to the bc plane

    N′-(5-Bromo-2-hydr­oxy-3-methoxy­benzyl­idene)isonicotinohydrazide

    Get PDF
    The title compound, C14H12BrN3O3, was prepared by reaction of 5-bromo-3-methoxy­salicylaldehyde and isonicotinohydrazide in methanol. The mol­ecule is not planar and adopts a trans configuration with respect to the C=N bond. There is an intra­molecular O—H⋯N hydrogen bond in the mol­ecule. The dihedral angle between the benzene and pyridine rings is 12.2 (2)°. In the crystal structure, mol­ecules are linked through inter­molecular N—H⋯N hydrogen bonds, forming chains running along the c-axis direction

    Poly A- Transcripts Expressed in HeLa Cells

    Get PDF
    BACKGROUND: Transcripts expressed in eukaryotes are classified as poly A+ transcripts or poly A- transcripts based on the presence or absence of the 3' poly A tail. Most transcripts identified so far are poly A+ transcripts, whereas the poly A- transcripts remain largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: We developed the TRD (Total RNA Detection) system for transcript identification. The system detects the transcripts through the following steps: 1) depleting the abundant ribosomal and small-size transcripts; 2) synthesizing cDNA without regard to the status of the 3' poly A tail; 3) applying the 454 sequencing technology for massive 3' EST collection from the cDNA; and 4) determining the genome origins of the detected transcripts by mapping the sequences to the human genome reference sequences. Using this system, we characterized the cytoplasmic transcripts from HeLa cells. Of the 13,467 distinct 3' ESTs analyzed, 24% are poly A-, 36% are poly A+, and 40% are bimorphic with poly A+ features but without the 3' poly A tail. Most of the poly A- 3' ESTs do not match known transcript sequences; they have a similar distribution pattern in the genome as the poly A+ and bimorphic 3' ESTs, and their mapped intergenic regions are evolutionarily conserved. Experiments confirmed the authenticity of the detected poly A- transcripts. CONCLUSION/SIGNIFICANCE: Our study provides the first large-scale sequence evidence for the presence of poly A- transcripts in eukaryotes. The abundance of the poly A- transcripts highlights the need for comprehensive identification of these transcripts for decoding the transcriptome, annotating the genome and studying biological relevance of the poly A- transcripts

    Associations Between Hepatitis B Virus Genotype and Mutants and the Risk of Hepatocellular Carcinoma

    Get PDF
    Background The risk of hepatocellular carcinoma (HCC) increases with increasing level of hepatitis B virus (HBV) in serum (viral load). However , it is unclear whether genetic characteristics of HBV, including HBV genotype and specific genetic mutations, contribute to the risk of HCC. We examined the HCC risk associated with HBV genotypes and common variants in the precore and basal core promoter (BCP) regions. Methods From January 5, 1991, to December 21, 1992 , baseline blood samples were collected from 2762 Taiwanese men and women who were seropositive for HBV surface antigen but had not been diagnosed with HCC; the samples were tested for HBV viral load by real-time polymerase chain reaction and genotyped by melting curve analysis. Participants who had a baseline serum HBV DNA level greater than 101 copies/ mL (n = 1526) were tested for the precore G 1896A and BCP A 1762T/G1764A mutants by direct sequencing. Incident cases of HCC were ascertained through follow-up examinations and computerized linkage to the National Cancer Registry and death certification profiles. A Cox proportional hazards model was used to estimate the risk of HCC associated with HBV genotype and precore and BCP mutants after adjustment for other risk factors. All statistical tests were two-sided . Results A total of 153 HCC cases occurred during 33847 person-years of follow-up. The HCC incidence rates per 100000 person-years for participants infected with HBV genotype B or C were 305.6 (95% confidence interval [CI] = 236.9 to 388.1) and 785.8 (95% CI = 626.8 to 972.9), respectively. Among participants with a baseline HBV DNA level of at least 10(4) copies/mL, HCC incidence per 100000 person-years was higher for those with the precore G1896 ( wild-type) variant than for those with the G1896A variant ( 955.5 [95% CI = 749.0 to 1201.4] vs 269.4 [95% CI = 172.6 to 400.9]) and for those with the BCP A1762T/G1764A double mutant than for those with BCP A1762/G1764 (wild-type) variant (1149.2 [95% CI = 872.6 to 1485.6] vs 358.7 [95% Cl = 255.1 to 490.4]). The multivariable-adjusted hazard ratio of developing HCC was 1.76 (95% CI = 1.19 to 2.61) for genotype C vs genotype B, 0.34 (95% CI = 0.21 to 0.57) for precore G1896A vs wild type, and 1.73 (95% CI = 1.13 to 2.67 ) for BCP A1762T/G1764A vs wild type. Risk was highest among participants infected with genotype C HBV and wild type for the precore 1896 variant and mutant for the BCP 1762/1764 variant ( adjusted hazard ratio = 2.99, 95% CI = 1.57 to 5.70 , P<.001). Conclusions HBV genotype C and specific alleles of BCP and precore were associated with risk of HCC. These associations were independent of serum HBV DNA level

    Metabolic Deregulation of the Blood-Outer Retinal Barrier in Retinitis Pigmentosa

    Get PDF
    Retinitis pigmentosa (RP) initiates with diminished rod photoreceptor function, causing peripheral and nighttime vision loss. However, subsequent loss of cone function and high-resolution daylight and color vision is most debilitating. Visual pigment-rich photoreceptor outer segments (OS) undergo phagocytosis by the retinal pigment epithelium (RPE), and the RPE also acts as a blood-outer retinal barrier transporting nutrients, including glucose, to photoreceptors. We provide evidence that contact between externalized phosphatidylserine (PS) on OS tips and apical RPE receptors activates Akt, linking phagocytosis with glucose transport to photoreceptors for new OS synthesis. As abundant mutant rod OS tips shorten in RP, Akt activation is lost, and onset of glucose metabolism in the RPE and diminished glucose transport combine to cause photoreceptor starvation and accompanying retinal metabolome changes. Subretinal injection of OS tip mimetics displaying PS restores Akt activation, glucose transport, and cone function in end-stage RP after rods are lost
    corecore