390 research outputs found
Evidence of Hot Carrier Extraction in Metal Halide Perovskite Solar Cells
The presence of hot carriers is presented in the operational properties of an
(FA,Cs)Pb(I, Br, Cl)3 solar cell at ambient temperatures and under practical
solar concentration. At 100 K, clear evidence of hot carriers is observed in
both the high energy tail of the photoluminescence spectra and from the
appearance of a non-equilibrium photocurrent at higher fluence in light J-V
measurements. At room temperature, however, the presence of hot carriers in the
emission at elevated laser fluence are shown to compete with a gradual red
shift in the PL peak energy as photo induced halide segregation begins to occur
at higher lattice temperature. The effects of thermionic emission of hot
carriers and the presence of a non-equilibrium carrier distribution are also
shown to be distinct from simple lattice heating. This results in large
unsaturated photocurrents at high powers as the Fermi distribution exceeds that
of the heterointerface controlling carrier transport and rectification
Potential Role of miRNAs in Developmental Haemostasis
MicroRNAs (miRNAs) are an abundant class of small non-coding RNAs that are negative regulators in a crescent number of physiological and pathological processes. However, their role in haemostasis, a complex physiological process involving multitude of effectors, is just beginning to be characterized. We evaluated the changes of expression of miRNAs in livers of neonates (day one after birth) and adult mice by microarray and qRT-PCR trying to identify miRNAs that potentially may also be involved in the control of the dramatic change of hepatic haemostatic protein levels associated with this transition. Twenty one out of 41 miRNAs overexpressed in neonate mice have hepatic haemostatic mRNA as potential targets. Six of them identified by two in silico algorithms potentially bind the 3′UTR regions of F7, F9, F12, FXIIIB, PLG and SERPINC1 mRNA. Interestingly, miR-18a and miR-19b, overexpressed 5.4 and 8.2-fold respectively in neonates, have antithrombin, a key anti-coagulant with strong anti-angiogenic and anti-inflammatory roles, as a potential target. The levels of these two miRNAs inversely correlated with antithrombin mRNA levels during development (miR-19b: R = 0.81; p = 0.03; miR-18a: R = 0.91; p<0.001). These data suggest that miRNAs could be potential modulators of the haemostatic system involved in developmental haemostasis
Genetic analysis of patients with Fuchs endothelial corneal dystrophy in India
<p>Abstract</p> <p>Background</p> <p>Mutations in <it>COL8A2 </it>gene which encodes the collagen alpha-2 (VIII) chain have been identified in both familial and sporadic cases of Fuchs endothelial corneal dystrophy (FECD). Heterozygous mutations in the <it>SLC4A11 </it>gene are also known to cause late-onset FECD. Therefore we screened for <it>COL8A2</it>, <it>SLC4A11 </it>gene variants in Indian FECD patients.</p> <p>Methods</p> <p>Eighty patients with clinically diagnosed FECD and 100 age matched normal individuals were recruited. Genomic DNA was isolated from peripheral blood leukocytes. Mutations in <it>COL8A2</it>, <it>SLC4A11 </it>coding regions were screened using bi-directional sequencing. Fischer's exact test or Pearson's chi squared test were used to predict the statistical association of genotypes with the phenotype.</p> <p>Results</p> <p>Screening of <it>COL8A2 </it>gene revealed 2 novel c.1610G>A, c.1643A>G and 3 reported variations c.112G>A, c.464G>A and c.1485G>A. In <it>SLC4A11 </it>gene, novel c.1659C>T, c.1974C>T and reported c.405G>A, c.481A>C and c.639G>A variants were identified. However all the variations in both the genes were also present in unaffected controls.</p> <p>Conclusions</p> <p>This is the first study analysing <it>COL8A2 </it>gene in Indian patients with FECD. No pathogenic mutations were identified in <it>COL8A2</it>. Merely silent changes, which showed statistically insignificant association with FECD, were identified in the screening of <it>SLC4A11 </it>gene. These results suggest that <it>COL8A2</it>, <it>SLC4A11 </it>genes may not be responsible for FECD in patients examined in this study.</p
Equivalences between localisations of categories provided by replacements
We give a characterisation of functors whose induced functor on the level of
localisations is an equivalence and where the isomorphism inverse is induced by
some kind of replacements such as projective resolutions or cofibrant
replacements
Estimating required information size by quantifying diversity in random-effects model meta-analyses
<p>Abstract</p> <p>Background</p> <p>There is increasing awareness that meta-analyses require a sufficiently large information size to detect or reject an anticipated intervention effect. The required information size in a meta-analysis may be calculated from an anticipated <it>a priori </it>intervention effect or from an intervention effect suggested by trials with low-risk of bias.</p> <p>Methods</p> <p>Information size calculations need to consider the total model variance in a meta-analysis to control type I and type II errors. Here, we derive an adjusting factor for the required information size under any random-effects model meta-analysis.</p> <p>Results</p> <p>We devise a measure of diversity (<it>D</it><sup>2</sup>) in a meta-analysis, which is the relative variance reduction when the meta-analysis model is changed from a random-effects into a fixed-effect model. <it>D</it><sup>2 </sup>is the percentage that the between-trial variability constitutes of the sum of the between-trial variability and a sampling error estimate considering the required information size. <it>D</it><sup>2 </sup>is different from the intuitively obvious adjusting factor based on the common quantification of heterogeneity, the inconsistency (<it>I</it><sup>2</sup>), which may underestimate the required information size. Thus, <it>D</it><sup>2 </sup>and <it>I</it><sup>2 </sup>are compared and interpreted using several simulations and clinical examples. In addition we show mathematically that diversity is equal to or greater than inconsistency, that is <it>D</it><sup>2 </sup>≥ <it>I</it><sup>2</sup>, for all meta-analyses.</p> <p>Conclusion</p> <p>We conclude that <it>D</it><sup>2 </sup>seems a better alternative than <it>I</it><sup>2 </sup>to consider model variation in any random-effects meta-analysis despite the choice of the between trial variance estimator that constitutes the model. Furthermore, <it>D</it><sup>2 </sup>can readily adjust the required information size in any random-effects model meta-analysis.</p
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