2,843 research outputs found
A New ZrCuSiAs-Type Superconductor: ThFeAsN
We report the first nitrogen-containing iron-pnictide superconductor ThFeAsN,
which is synthesized by a solid-state reaction in an evacuated container. The
compound crystallizes in a ZrCuSiAs-type structure with the space group P4/nmm
and lattice parameters a=4.0367(1) {\AA} and c=8.5262(2) {\AA} at 300 K. The
electrical resistivity and dc magnetic susceptibility measurements indicate
superconductivity at 30 K for the nominally undoped ThFeAsN.Comment: 6 pages, 4 figures, 1 tabl
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Maternal caffeine intake during pregnancy is associated with risk of low birth weight: a systematic review and dose–response meta-analysis
Background: Considerable controversy exists regarding the relation between maternal caffeine intake during pregnancy and risk of low birth weight (birth weight <2,500 g). We aim to assess this association using a systematic review and dose–response meta-analysis of prospective studies. Methods: Potential articles were identified by searching MEDLINE and SCOPUS databases through 17 July 2013. Two authors independently extracted information on study design, participant characteristics and estimates of associations. Random-effects models were used to derive the summary relative risks (RRs) and corresponding 95% confidence intervals (CIs). Dose–response relationships were assessed using generalized least-squares trend estimation. Results: In our meta-analysis, we included 13 prospective studies: 9 with low birth weight as a binary outcome variable (90,747 participants and 6,303 cases) and 6 with birth weight as a continuous outcome variable (10,015 participants; 2 studies reported both types of outcomes). Compared with the reference category with no or very low caffeine intake, the RR (95% CI) of low birth weight was 1.13 (1.06 to 1.21; I2 0.0%) for low intake (50 to 149 mg/day), 1.38 (1.18 to 1.62; I2 31.9%) for moderate intake (150 to 349 mg/day), and 1.60 (1.24 to 2.08; I2 65.8%) for high intake (≥350 mg/day). In the dose–response analysis, each 100-mg/day increment in maternal caffeine intake (around one cup of coffee) was associated with 13% (RR 1.13, 1.06 to 1.21) higher risk of low birth weight. The association persisted in strata defined according to various study characteristics. Moderate (−33 g, 95% CI −63 to −4; I2 0.3%) and high (−69 g, 95% CI −102 to −35; I2 0.0%) caffeine intakes were also associated with a significantly lower birth weight as compared with the reference category. Conclusions: Higher maternal caffeine intake during pregnancy was associated with a higher risk of delivering low birth weight infants. These findings support recommendations to restrict caffeine intake during pregnancy to low levels. Electronic supplementary material The online version of this article (doi:10.1186/s12916-014-0174-6) contains supplementary material, which is available to authorized users
Y Chromosomes of 40% Chinese Are Descendants of Three Neolithic Super-grandfathers
Demographic change of human populations is one of the central questions for
delving into the past of human beings. To identify major population expansions
related to male lineages, we sequenced 78 East Asian Y chromosomes at 3.9 Mbp
of the non-recombining region (NRY), discovered >4,000 new SNPs, and identified
many new clades. The relative divergence dates can be estimated much more
precisely using molecular clock. We found that all the Paleolithic divergences
were binary; however, three strong star-like Neolithic expansions at ~6 kya
(thousand years ago) (assuming a constant substitution rate of 1e-9/bp/year)
indicates that ~40% of modern Chinese are patrilineal descendants of only three
super-grandfathers at that time. This observation suggests that the main
patrilineal expansion in China occurred in the Neolithic Era and might be
related to the development of agriculture.Comment: 29 pages of article text including 1 article figure, 9 pages of SI
text, and 2 SI figures. 5 SI tables are in a separate ancillary fil
The nucleolar protein NIFK promotes cancer progression via CK1α/β-catenin in metastasis and Ki-67-dependent cell proliferation.
Nucleolar protein interacting with the FHA domain of pKi-67 (NIFK) is a Ki-67-interacting protein. However, its precise function in cancer remains largely uninvestigated. Here we show the clinical significance and metastatic mechanism of NIFK in lung cancer. NIFK expression is clinically associated with poor prognosis and metastasis. Furthermore, NIFK enhances Ki-67-dependent proliferation, and promotes migration, invasion in vitro and metastasis in vivo via downregulation of casein kinase 1α (CK1α), a suppressor of pro-metastatic TCF4/β-catenin signaling. Inversely, CK1α is upregulated upon NIFK knockdown. The silencing of CK1α expression in NIFK-silenced cells restores TCF4/β-catenin transcriptional activity, cell migration, and metastasis. Furthermore, RUNX1 is identified as a transcription factor of CSNK1A1 (CK1α) that is negatively regulated by NIFK. Our results demonstrate the prognostic value of NIFK, and suggest that NIFK is required for lung cancer progression via the RUNX1-dependent CK1α repression, which activates TCF4/β-catenin signaling in metastasis and the Ki-67-dependent regulation in cell proliferation
Listen to genes : dealing with microarray data in the frequency domain
Background: We present a novel and systematic approach to analyze temporal microarray data. The approach includes
normalization, clustering and network analysis of genes.
Methodology: Genes are normalized using an error model based uniform normalization method aimed at identifying and
estimating the sources of variations. The model minimizes the correlation among error terms across replicates. The
normalized gene expressions are then clustered in terms of their power spectrum density. The method of complex Granger
causality is introduced to reveal interactions between sets of genes. Complex Granger causality along with partial Granger
causality is applied in both time and frequency domains to selected as well as all the genes to reveal the interesting
networks of interactions. The approach is successfully applied to Arabidopsis leaf microarray data generated from 31,000
genes observed over 22 time points over 22 days. Three circuits: a circadian gene circuit, an ethylene circuit and a new
global circuit showing a hierarchical structure to determine the initiators of leaf senescence are analyzed in detail.
Conclusions: We use a totally data-driven approach to form biological hypothesis. Clustering using the power-spectrum
analysis helps us identify genes of potential interest. Their dynamics can be captured accurately in the time and frequency
domain using the methods of complex and partial Granger causality. With the rise in availability of temporal microarray
data, such methods can be useful tools in uncovering the hidden biological interactions. We show our method in a step by
step manner with help of toy models as well as a real biological dataset. We also analyse three distinct gene circuits of
potential interest to Arabidopsis researchers
N-(2-Chloro-2-nitro-1-phenylpropyl)-4-methylbenzenesulfonamide
In the title compound, C16H17ClN2O4S, the dihedral angle between the phenyl and benzene rings is 19.4 (2)°. The crystal packing is stabilized by intermolecular N—H⋯O hydrogen bonds, as well as by intra- and intermolecular C—H⋯O hydrogen bonds
Financial production marketing prediction based on optimization GA-BP neural network
The traditional BP neural network has some application problems.For example,the network structure parameter is too dependent on experience and easy to fall into local solution.In order to improve the application defects of BP neural network model,the optimization GA-BP algorithm to optimize BP neural network topology and the selection process of network initial parameter value is proposed.In order to verify the feasibility of the model,marketing customer historical data of a bank short-term financial products as the research object is used to validate the model which could more accurately predict the customer compared with BP neural network model.The test results show that the model could be applied to analysis financial product marketing data and more accurately predict the future marketing results
Constraints on Spin-Independent Nucleus Scattering with sub-GeV Weakly Interacting Massive Particle Dark Matter from the CDEX-1B Experiment at the China Jin-Ping Laboratory
We report results on the searches of weakly interacting massive particles
(WIMPs) with sub-GeV masses () via WIMP-nucleus spin-independent
scattering with Migdal effect incorporated. Analysis on time-integrated (TI)
and annual modulation (AM) effects on CDEX-1B data are performed, with 737.1
kgday exposure and 160 eVee threshold for TI analysis, and 1107.5
kgday exposure and 250 eVee threshold for AM analysis. The sensitive
windows in are expanded by an order of magnitude to lower DM masses
with Migdal effect incorporated. New limits on at
90\% confidence level are derived as 1010
for TI analysis at 50180 MeV/, and
1010 for AM analysis at
75 MeV/3.0 GeV/.Comment: 5 pages, 4 figure
Pairing symmetry and properties of iron-based high temperature superconductors
Pairing symmetry is important to indentify the pairing mechanism. The
analysis becomes particularly timely and important for the newly discovered
iron-based multi-orbital superconductors. From group theory point of view we
classified all pairing matrices (in the orbital space) that carry irreducible
representations of the system. The quasiparticle gap falls into three
categories: full, nodal and gapless. The nodal-gap states show conventional
Volovik effect even for on-site pairing. The gapless states are odd in orbital
space, have a negative superfluid density and are therefore unstable. In
connection to experiments we proposed possible pairing states and implications
for the pairing mechanism.Comment: 4 pages, 1 table, 2 figures, polished versio
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