14,052 research outputs found

    Highly Stable Sr-Free Cobaltite-Based Perovskite Cathodes Directly Assembled on a Barrier-Layer-Free Y2O3-ZrO2 Electrolyte of Solid Oxide Fuel Cells

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    Direct assembly is a newly developed technique in which a cobaltite-based perovskite (CBP) cathode can be directly applied to a barrier-layer-free Y2O3-ZrO2 (YSZ) electrolyte with no high-temperature pre-sintering steps. Solid oxide fuel cells (SOFCs) based on directly assembled CBPs such as La0.6Sr0.4Co0.2Fe0.8O3-d show high performance initially but degrade rapidly under SOFC operation conditions at 750 °C owing to Sr segregation and accumulation at the electrode/electrolyte interface. Herein, the performance and interface of Sr-free CBPs such as LaCoO3-d (LC) and Sm0.95CoO3-d (SmC) and their composite cathodes directly assembled on YSZ electrolyte was studied systematically. The LC electrode underwent performance degradation, most likely owing to cation demixing and accumulation of La on the YSZ electrolyte under polarization at 500 mA cm-2 and 750 °C. However, the performance and stability of LC electrodes could be substantially enhanced by the formation of LC-gadolinium-doped ceria (GDC) composite cathodes. Replacement of La by Sm increased the cell stability, and doping of 5 % Pd to form Sm0.95Co0.95Pd0.05O3-d (SmCPd) significantly improved the electrode activity. An anode-supported YSZ-electrolyte cell with a directly assembled SmCPd-GDC composite electrode exhibited a peak power density of 1.4 W cm-2 at 750 °C, and an excellent stability at 750 °C for over 240 h. The higher stability of SmC as compared to that of LC is most likely a result of the lower reactivity of SmC with YSZ. This study demonstrates the new opportunities in the design and development of intermediate-temperature SOFCs based on the directly assembled high-performance and durable Sr-free CBP cathodes

    Antisense oligonucleotide: A potential therapeutic intervention for chronic kidney disease

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    Chronic kidney disease (CKD) is a global public health issue that places an increasing burden on the healthcare systems of both the developed and developing countries. CKD is a progressive and irreversible condition, affecting approximately 10% of the population worldwide. Patients that have progressed to end-stage renal disease (ESRD) require expensive renal replacement therapy, i.e., dialysis or kidney transplantation. Current CKD therapy largely relies on the use of angiotensin-converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs). However, these treatments by no means halt the progression of CKD to ESRD. Therefore, the development of new therapies is urgently needed. Antisense oligonucleotide (ASO) has recently attracted considerable interest as a drug development platform. Thus far, eight ASO-based drugs have been granted approval by the US Food and Drug Administration for the treatment of various diseases. Herein, we review the ASOs developed for the identification of CKD-relevant genes and/or the simultaneous development of the ASOs as potential therapeutics towards treating CKD

    Rectification of electronic heat current by a hybrid thermal diode

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    We report the realization of an ultra-efficient low-temperature hybrid heat current rectifier, thermal counterpart of the well-known electric diode. Our design is based on a tunnel junction between two different elements: a normal metal and a superconducting island. Electronic heat current asymmetry in the structure arises from large mismatch between the thermal properties of these two. We demonstrate experimentally temperature differences exceeding 6060 mK between the forward and reverse thermal bias configurations. Our device offers a remarkably large heat rectification ratio up to 140\sim 140 and allows its prompt implementation in true solid-state thermal nanocircuits and general-purpose electronic applications requiring energy harvesting or thermal management and isolation at the nanoscale.Comment: 8 pages, 6 color figure

    The effects of socioeconomic status and indices of physical environment on reduced birth weight and preterm births in Eastern Massachusetts

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Air pollution and social characteristics have been shown to affect indicators of health. While use of spatial methods to estimate exposure to air pollution has increased the power to detect effects, questions have been raised about potential for confounding by social factors.Methods: A study of singleton births in Eastern Massachusetts was conducted between 1996 and 2002 to examine the association between indicators of traffic, land use, individual and area-based socioeconomic measures (SEM), and birth outcomes ( birth weight, small for gestational age and preterm births), in a two-level hierarchical model.Results: We found effects of both individual ( education, race, prenatal care index) and area-based ( median household income) SEM with all birth outcomes. The associations for traffic and land use variables were mainly seen with birth weight, with an exception for an effect of cumulative traffic density on small for gestational age. Race/ethnicity of mother was an important predictor of birth outcomes and a strong confounder for both area-based SEM and indices of physical environment. The effects of traffic and land use differed by level of education and median household income.Conclusion: Overall, the findings of the study suggested greater likelihood of reduced birth weight and preterm births among the more socially disadvantaged, and a greater risk of reduced birth weight associated with traffic exposures. Results revealed the importance of controlling simultaneously for SEM and environmental exposures as the way to better understand determinants of health.This work is supported by the Harvard Environmental Protection Agency (EPA) Center, Grants R827353 and R-832416, and National Institute for Environmental Health Science (NIEHS) ES-0002

    Identification of a pleiotropic locus on chromosome 7q for a composite left ventricular wall thickness factor and body mass index: the HyperGEN Study

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    <p>Abstract</p> <p>Background</p> <p>Left ventricular (LV) mass and wall thickness are closely associated with measures of body size and blood pressure and also correlated with systolic and diastolic function, suggesting a contribution of common physiologic mechanisms, including pleiotropic genes, to their covariation.</p> <p>Methods</p> <p>Doppler echocardiography was performed in 434 African-American (1344 individuals) and 284 white families (1119 individuals). We conducted a genome-wide linkage scan for LV mass, LV structure and function, and composite factors derived from a factor analysis of LV structure and function in the HyperGEN Study population.</p> <p>Results</p> <p>Factor analysis identified (i) a LV wall thickness factor correlated strongly with interventricular septal thickness (IVSTd) and posterior wall thickness (PWTd) and (ii) a LV diastolic filling factor strongly correlated with early and atrial phase peak transmitral filling velocities. The LV phenotypes and composite factor scores were analyzed in multipoint variance components linkage model implemented in SOLAR with 387 microsatellite markers. In whites, the two highest LODs were 3.42 for LV atrial phase peak filling velocity at 144 cM on chromosome 1 and 3.12 for the LV wall thickness factor at 160 cM on chromosome 7. The peak LODs of the component traits (IVSTd and PWTd) clustered at the same region as the composite factor. Adjusting the factor score for body mass index (BMI) substantially reduced the peak LOD at this region (LOD = 1.92). Bivariate linkage analysis of the composite factor with BMI improved LOD to 3.42 at 158 cM. Also in whites, suggestive linkage was observed on chromosomes 2 and 4 for LV mass, chromosomes 3, 5, 10, and 17 for LV atrial phase peak filling velocity, and chromosome 10 for LV diastolic filling factor. In African Americans, suggestive linkage was observed on chromosome 12 for LV mass, chromosome 21 for IVSTd, and chromosome 3 for LV internal diameter at end-diastole.</p> <p>Conclusion</p> <p>Our study suggests that a region on chromosome 7 contains pleiotropic genes contributing to the variations of both LV wall thickness and BMI in whites.</p

    Both piRNA and siRNA Pathways Are Silencing Transcripts of the Suffix Element in the Drosophila melanogaster Germline and Somatic Cells

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    In the Drosophila melanogaster germline, the piRNA pathway silences retrotransposons as well as other transcribed repetitive elements. Suffix is an unusual short retroelement that was identified both as an actively transcribed repetitive element and also as an element at the 3′ ends of the Drosophila non-LTR F element. The copies of suffix that are F element-independent are far more actively transcribed than their counterparts on the F element. We studied the patterns of small RNAs targeting both strands of suffix in Drosophila ovaries using an RNase protection assay and the analysis of the corresponding RNA sequences from the libraries of total small RNAs. Our results indicate that suffix sense and antisense transcripts are targeted mainly by 23–29 nucleotides in length piRNAs and also by 21 nucleotides in length siRNAs. Suffix sense transcripts actively form longer RNA species, corresponding either to partial digestion products of the RNAi and Piwi pathways or to another RNA silencing mechanism. Both sense and antisense suffix transcripts accumulated in the ovaries of homozygous spn-E, piwi and aub mutants. These results provide evidence that suffix sense and antisense transcripts in the germ line and soma are targeted by both RNAi and Piwi pathways and that a Dicer-independent pathway of biogenesis of siRNAs could exist in Drosophila cells

    A consistent picture for large penguins in D -> pi+ pi-, K+ K-

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    A long-standing puzzle in charm physics is the large difference between the D0 -> K+ K- and D0 -> pi+ pi- decay rates. Recently, the LHCb and CDF collaborations reported a surprisingly large difference between the direct CP asymmetries, Delta A_CP, in these two modes. We show that the two puzzles are naturally related in the Standard Model via s- and d-quark "penguin contractions". Their sum gives rise to Delta A_CP, while their difference contributes to the two branching ratios with opposite sign. Assuming nominal SU(3) breaking, a U-spin fit to the D0 -> K+ pi-, pi+ K-, pi+ pi-, K+ K- decay rates yields large penguin contractions that naturally explain Delta A_CP. Expectations for the individual CP asymmetries are also discussed.Comment: 24 pages, 8 figure

    Escherichia coli induces apoptosis and proliferation of mammary cells

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    Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection, The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1 beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection, Induction of matrix metalloproteinase-g, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue, These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation

    A new parametric equation of state and quark stars

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    It is still a matter of debate to understand the equation of state of cold supra-nuclear matter in compact stars because of unknown on-perturbative strong interaction between quarks. Nevertheless, it is speculated from an astrophysical view point that quark clusters could form in cold quark matter due to strong coupling at realistic baryon densities. Although it is hard to calculate this conjectured matter from first principles, one can expect the inter-cluster interaction to share some general features to nucleon-nucleon interaction. We adopt a two-Gaussian component soft-core potential with these general features and show that quark clusters can form stable simple cubic crystal structure if we assume Gaussian form wave function. With this parameterizing, Tolman-Oppenheimer-Volkoff equation is solved with reasonable constrained parameter space to give mass-radius relation of crystalline solid quark star. With baryon densities truncated at 2 times nuclear density at surface and range of interaction fixed at 2fm we can reproduce similar mass-radius relation to that obtained with bag model equations of state. The maximum mass ranges from about 0.5 to 3 solar mass. Observed maximum pulsar mass (about 2 solar mass) is then used to constrain parameters of this simple interaction potential.Comment: 5 pages, 2 figure

    Analysis on the clinical features of 22 basaloid squamous cell carcinoma of the lung

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    <p>Abstract</p> <p>Background</p> <p>Basaloid squamous cell carcinoma of the lung is a rare and highly malignant tumor mostly observed in the proximal bronchi. Basaloid squamous cell carcinoma of the lung cases typically show rapid clinical progression, very poor prognosis and special pathological morphology. This project aimed to examine the clinical features of basaloid squamous cell carcinoma of the lung and the factors related to its prognosis; and to compare survival outcomes between basaloid squamous cell carcinoma and poorly differentiated squamous cell carcinomas (PDSC).</p> <p>Methods</p> <p>Between January 2004 and December 2008, pathological sections from basaloid squamous cell carcinoma and PDSC of the lung were collected and retrospectively analyzed at Tianjin Medical University Cancer Institute and Hospital. Data analysis was performed using Statistical Package for the Social Sciences (SPSS11.0). The Kaplan-Meier method was used to calculate the survival rate. Log-rank test was used to compare the differences in survival rate between the two groups. The factors influencing prognosis were analyzed using the Cox proportional hazard model.</p> <p>Results</p> <p>A total of 120 pathological sections were used in the analysis of this study-22 from basaloid squamous cell carcinoma cases and 98 from PDSC cases. Compared to the PDSC group, the basaloid squamous cell carcinoma group had a larger proportion of female patients (p = 0.001); however it had higher proportion of male smokers (p = 0.003). There were no statistically significant differences in survival rate between the two groups (χ<sup>2 </sup>= 1.200, p = 0.273). Additionally, prognosis of basaloid squamous cell carcinoma is significantly influenced by treatment mode and clinical stages of the tumor. The post-operation mortality hazard of patients treated with a combination chemotherapy and radiotherapy was 1.296 times higher than other treatment modes (<it>p </it>= 0.025). Increases in post-operation mortality hazard ratio were also associated with more advanced clinical stage of tumors (χ<sup>2 </sup>trend = 11.907, <it>p </it>= 0.000).</p> <p>Conclusions</p> <p>This study demonstrated that basaloid squamous cell carcinoma and PDSC have very similar clinical features, and there are no significant differences in survival rates between the two groups. Hence, we conclude that in the short term, the same clinical treatments and therapeutic modes can be administered to patients with basaloid squamous cell carcinoma and PDSC of the lung.</p
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