16 research outputs found
Patent thickets, licensing and innovative performance
We examine the relationship between fragmented intellectual property (IP) rights and the innovative performance of firms, taking into consideration the role played by in-licensing of IP. We find that firms facing more fragmented IP landscapes have a higher probability of in-licensing. We observe a negative relationship between IP fragmentation and innovative performance, but only for firms that engage in in-licensing. In contrast, greater IP fragmentation is associated with higher innovative performance for firms that do not in-license. Furthermore, the effects of fragmentation on innovation also appear to depend on the size of a firm's patent portfolio. These results suggest that the effects of fragmentation of upstream IP rights are not uniform, and instead vary according to the characteristics of the downstream firm. Copyright 2010 The Author 2010. Published by Oxford University Press on behalf of Associazione ICC. All rights reserved., Oxford University Press.
Removal of Oxide Nanoparticles in a Model Wastewater Treatment Plant: Influence of Agglomeration and Surfactants on Clearing Efficiency
Platelet Microparticles Enhance the Vasoregenerative Potential of Angiogenic Early Outgrowth Cells After Vascular Injury
Performance-Enhancing Asymmetric Separator for Lithium–Sulfur Batteries
Asymmetric
separators with polysulfide barrier properties consisting of porous
polypropylene grafted with styrenesulfonate (PP<i>-<i>g</i>-</i>PLiSS) were characterized in lithium–sulfur cells
to assess their practical applicability. Galvanostatic cycling at
different C-rates with and without an electrolyte additive and cyclic
voltammetry were used to probe the electrochemical performance of
the cells with the PP<i>-<i>g</i>-</i>PLiSS separators
and to compare it with the performance of the cells utilizing state-of-the-art
separator, Celgard 2400. Overall, it was found that regardless of
the applied cycling rate, the use of the grafted separators greatly
enhances the Coulombic efficiency of the cell. An appropriate Li-exchange-site
(−SO<sub>3</sub><sup>–</sup>) concentration at and near
the surface of the separator was found to be essential to effectively
suppress the polysulfide shuttle without sacrificing the Li-ion mobility
through the separator and to improve the practical specific charge
of the cell
Radiochemical Determination of Long-Lived Radionuclides in Proton-Irradiated Heavy-Metal Targets: Part ITantalum
In
this study, distillation, precipitation, and ion-exchange methods
were chosen for the separation of the long-lived β-emitters <sup>129</sup>I, <sup>36</sup>Cl and the α-emitters <sup>154</sup>Dy, <sup>148</sup>Gd, <sup>150</sup>Gd, and <sup>146</sup>Sm from
Ta targets irradiated with protons up to 2.6 GeV to determine their
production cross sections. Measurements of <sup>129</sup>I/<sup>127</sup>I and <sup>36</sup>Cl/<sup>35</sup>Cl ratios were performed with
accelerator mass spectrometry. After separation of the lanthanides,
the molecular plating technique was applied to prepare thin samples
to obtain highly resolved α-spectra. Autoradiography and focused
ion beam/scanning electron microscopy techniques were used to characterize
the lanthanide deposited layer. Experimental cross-section data are
compared with theoretical predictions obtained with INCL++ and ABLA07
code, and a satisfactory agreement is observed
The CLIMTREE Project: Ecological and socioeconomic impacts of climate-induced tree diebacks in highland forests
International audienc
The Extent of Platinum-Induced Hydrogen Spillover on Cerium Dioxide
Hydrogen spillover from metal nanoparticles to oxides
is an essential
process in hydrogenation catalysis and other applications such as
hydrogen storage. It is important to understand how far this process
is reaching over the surface of the oxide. Here, we present a combination
of advanced sample fabrication of a model system and in situ X-ray
photoelectron spectroscopy to disentangle local and far-reaching effects
of hydrogen spillover in a platinum–ceria catalyst. At low
temperatures (25–100 °C and 1 mbar H2) surface
O–H formed by hydrogen spillover on the whole ceria surface
extending microns away from the platinum, leading to a reduction of
Ce4+ to Ce3+. This process and structures were
strongly temperature dependent. At temperatures above 150 °C
(at 1 mbar H2), O–H partially disappeared from the
surface due to its decreasing thermodynamic stability. This resulted
in a ceria reoxidation. Higher hydrogen pressures are likely to shift
these transition temperatures upward due to the increasing chemical
potential. The findings reveal that on a catalyst containing a structure
capable to promote spillover, hydrogen can affect the whole catalyst
surface and be involved in catalysis and restructuring
Biochemical and Biophysical Analysis of a Chiral PqsD Inhibitor Revealing Tight-binding Behavior and Enantiomers with Contrary Thermodynamic Signatures
Antivirulence strategies addressing
bacterial pathogenicity without
exhibiting growth inhibition effects represent a novel approach to
overcome today’s crisis in antibiotic development. In recent
studies, we examined various inhibitors of PqsD, an enzyme involved
in formation of <i>Pseudomonas aeruginosa</i> cell-to-cell
signaling molecules, and observed desired cellular effects for 2-nitrophenyl
derivatives. Herein, we investigated the binding characteristics of
this interesting compound class using several biochemical and biophysical
methods. The inhibitors showed time-dependent activity, tight-binding
behavior, and interactions with the catalytic center. Furthermore,
isothermal titration calorimetry (ITC) experiments with separated
enantiomers revealed contrary thermodynamic signatures showing either
enthalpy- or entropy-driven affinity. A combination of site-directed
mutagenesis and thermodynamic profiling was used to identify key residues
involved in inhibitor binding. This information allowed the proposal
of experimentally confirmed docking poses. Although originally designed
as transition state analogs, our results suggest an altered position
for both enantiomers. Interestingly, the main difference between stereoisomers
was found in the orientation of the hydroxyl group at the stereogenic
center. The predicted binding modes are in accordance with experimental
data and, thus, allow future structure-guided optimization
Structure Optimization of 2‑Benzamidobenzoic Acids as PqsD Inhibitors for Pseudomonas aeruginosa Infections and Elucidation of Binding Mode by SPR, STD NMR, and Molecular Docking
Pseudomonas aeruginosa employs a
characteristic <i>pqs</i> quorum sensing (QS) system that
functions via the signal molecules PQS and its precursor HHQ. They
control the production of a number of virulence factors and biofilm
formation. Recently, we have shown that sulfonamide substituted 2-benzamidobenzoic
acids, which are known FabH inhibitors, are also able to inhibit PqsD,
the enzyme catalyzing the last and key step in the biosynthesis of
HHQ. Here, we describe the further optimization and characterization
of this class of compounds as PqsD inhibitors. Structural modifications
showed that both the carboxylic acid <i>ortho</i> to the
amide and 3′-sulfonamide are essential for binding. Introduction
of substituents in the anthranilic part of the molecule resulted in
compounds with IC<sub>50</sub> values in the low micromolar range.
Binding mode investigations by SPR with wild-type and mutated PqsD
revealed that this compound class does not bind into the active center
of PqsD but in the ACoA channel, preventing the substrate from accessing
the active site. This binding mode was further confirmed by docking
studies and STD NMR
Poly(Methyl Vinyl Ketone) as a Potential Carbon Fiber Precursor
Given
their increasing importance in a variety of applications,
the preparation of carbon fibers with well-defined chemical structures
and innocuous byproducts has garnered a growing interest over the
past decade. We report the preparation of medium molecular weight
poly(methyl vinyl ketone) (PMVK) as a potential carbon fiber precursor
material which can easily undergo carbonization via the well-known,
acid-catalyzed aldol condensation with water as a sole byproduct.
Rheological studies further show that PMVK (MW ∼ 50 kg/mol)
exhibits excellent physical and thermal properties for the spinning
of single and multifilament fibers and easily produces carbon yields
of 25% at temperatures as low as 250 °C. Analysis of the carbonized
product also suggests a more defect-free structure than commercially
available carbon fibers