899 research outputs found
The effect of competitive public funding on scientific output
Public funding is believed to play an important role in the development of science and technology.
However, whether public funding and, in particular, competitive funding from public agencies
actually helps to increase scientific output (i.e. publications) remains a matter of debate. By
analysing a dataset of co-publications between China and the EU and a dataset of joint project collaborations
in European Framework Programs for Research and Innovation [FP7 and Horizon
2020 (H2020)], we investigate whether different public funding agencies’ competitive assets have
different impact on the volume of publication output. Our results support the hypotheses that
competitively funded research output varies by funding sources, so that a high level of funding
does not necessarily lead to high scientific output. Our results sho
Coarse-grained modeling study of nonpeptide RGD ligand density and PEG molecular weight on the conformation of poly(γ-glutamyl-glutamate) paclitaxel conjugates
Molecular shape, flexibility, and surface hydrophilicity are thought to influence the ability of nanoparticles to cross biological barriers during drug delivery. In this study, coarse-grained (CG) molecular dynamics (MD) simulations were used to study these properties of a polymer-drug construct in potential clinical development: poly(γ-glutamyl-glutamate)-paclitaxel-poly(ethylene glycol) nonpeptide RGD (PGG-PTX-PEG-npRGD), a linear glutamyl-glutamate polymer with paclitaxel and poly(ethylene glycol)-nonpeptide RGD side groups. It was hypothesized that the PEG molecular weight (MW) (500 Da; 1,000 Da; and 2,000 Da) and nonpeptide RGD ligand density (4, 8, 12, and 16 per molecule), respectively, may have advantageous effects on the shape, flexibility, and surface hydrophilicity of PGG-PTX-PEG-npRGD. Circular dichroism spectroscopy was used to suggest initial structures for the all-atom (AA) models of PGG-PTX-PEG-npRGD, which were further converted to CG models using a commercially available mapping algorithm. Due to its semi-flexibility, PGG-PTX-PEG-npRGD is not limited to one specific conformation. Thus, CG MD simulations were run until statistical equilibrium, at which PGG-PTX-PEG-npRGD is represented as an ensemble of statistically similar conformations. The size of a PGG-PTX-PEG-npRGD molecule is not affected by the PEG MW or the nonpeptide RGD density, but higher PEG MW results in increased surface density of a PGG-PTX-PEG-npRGD molecule. Most PGG-PTX-PEG-npRGD shapes are globular, although filamentous shapes were also observed in the PEG500 and PEG1000 molecules. PEG500 and PEG1000 molecules are more flexible than PEG2000 systems. A higher presence of npRGD ligands results in decrease surface hydrophilicity of PGG-PTX-PEG-npRGD. These results indicate that the PGG-PTX-PEG1000-npRGD4 and PGG-PTX-PEG1000-npRGD8 molecules are the most efficacious candidates and are further recommended for experimental preclinical studies
Isolation and molecular characterization of RcSERK1: A Rosa canina gene transcriptionally induced during initiation of protocorm-like bodies
A somatic embryogensis receptor-like kinase (SERK) gene was isolated from protocorm-like bodies (PLBs) of Rosa canina by a rapid amplification of cDNA ends (RACE) approach and was designated as RcSERK1. The RcSERK1 encodes a protein of 626 amino acid residues with a calculated molecular mass of 68.79 kDa and theoretical isoelectric point of 5.65. The amino acid sequence of RcSERK1 shares all the characteristic features of a SERK protein, including the signal peptide (SP), the leucine zipper (LZ), the five leucine-rich repeats (LRRs), the pro-rich domain containing the so-called Ser-Pro- Pro (SPP) motif, the transmembrane domain (TM), the kinase domain and the C-terminal domain. The transcripts of RcSERK1 were more enriched in PLBs than in rhizoids and callus, but not detected in leaflets (incubated under dark and before producing callus) and the regenerated shoots. Subcellular localization indicated that the fluorescence of RcSERK1-GFP was recorded in the plasma membrane. We argue that RcSERK1 is a Leu-rich repeat receptor-like kinase (LRR-RLK) and plasma membrane localization protein.Keywords: somatic embryogensis receptor-like kinase (SERK)1, protocorm-like bodies (PLBs), Rosa canina, RACE, RcSERK1
Detection of a superconducting phase in a two-atom layer of hexagonal Ga film grown on semiconducting GaN(0001)
The recent observation of superconducting state at atomic scale has motivated
the pursuit of exotic condensed phases in two-dimensional (2D) systems. Here we
report on a superconducting phase in two-monolayer crystalline Ga films
epitaxially grown on wide band-gap semiconductor GaN(0001). This phase exhibits
a hexagonal structure and only 0.552 nm in thickness, nevertheless, brings
about a superconducting transition temperature Tc as high as 5.4 K, confirmed
by in situ scanning tunneling spectroscopy, and ex situ electrical
magneto-transport and magnetization measurements. The anisotropy of critical
magnetic field and Berezinski-Kosterlitz-Thouless-like transition are observed,
typical for the 2D superconductivity. Our results demonstrate a novel platform
for exploring atomic-scale 2D superconductor, with great potential for
understanding of the interface superconductivity
Phase Separation and Magnetic Order in K-doped Iron Selenide Superconductor
Alkali-doped iron selenide is the latest member of high Tc superconductor
family, and its peculiar characters have immediately attracted extensive
attention. We prepared high-quality potassium-doped iron selenide (KxFe2-ySe2)
thin films by molecular beam epitaxy and unambiguously demonstrated the
existence of phase separation, which is currently under debate, in this
material using scanning tunneling microscopy and spectroscopy. The
stoichiometric superconducting phase KFe2Se2 contains no iron vacancies, while
the insulating phase has a \surd5\times\surd5 vacancy order. The iron vacancies
are shown always destructive to superconductivity in KFe2Se2. Our study on the
subgap bound states induced by the iron vacancies further reveals a
magnetically-related bipartite order in the superconducting phase. These
findings not only solve the existing controversies in the atomic and electronic
structures in KxFe2-ySe2, but also provide valuable information on
understanding the superconductivity and its interplay with magnetism in
iron-based superconductors
2D materials beyond graphene for high-performance energy storage applications
Energy crisis is one of the most urgent and critical issues in our modern society. Currently, there is an increasing demand for efficient, low-cost, light-weight, flexible and environmentally benign, small-, medium-, and large-scale energy storage devices, which can be used to power smart grids, portable electronic devices, and electric vehicles. Novel electrode materials, with a high energy density at high power are urgently needed for realizing high-performance energy storage devices. The recent development in the field of 2D materials, including both graphene and other layered systems, has shown promise for a wide range of applications. In particular, graphene analogues, due to their remarkable electrochemical properties, have shown great potential in energy-related applications. This review aims at providing an overview of current research and important advances on the development of 2D materials beyond graphene for supercapacitors and batteries. The major challenges to be tackled, and more generally the future directions in the field, are also highlighted
Search for the Lepton Flavor Violation Process at BESIII
We search for the lepton-flavor-violating decay of the into an
electron and a muon using events
collected with the BESIII detector at the BEPCII collider. Four candidate
events are found in the signal region, consistent with background expectations.
An upper limit on the branching fraction of (90% C.L.) is obtained
Search for Baryonic Decays of \psi(3770) and \psi(4040)
By analyzing data samples of 2.9 fb^{-1} collected at \sqrt s=3.773 GeV, 482
pb^{-1} collected at \sqrt s=4.009 GeV and 67 pb^{-1} collected at \sqrt
s=3.542, 3.554, 3.561, 3.600 and 3.650 GeV with the BESIII detector at the
BEPCII storage ring, we search for \psi(3770) and \psi(4040) decay to baryonic
final states, including \Lambda\bar\Lambda\pi^+\pi^-, \Lambda \bar\Lambda\pi^0,
\Lambda\bar\Lambda\eta, \Sigma^+ \bar\Sigma^-, \Sigma^0 \bar\Sigma^0,
\Xi^-\bar\Xi^+ and \Xi^0\bar\Xi^0 decays. None are observed, and upper limits
are set at the 90% confidence level.Comment: 9 pages, 3 figure
- …