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Unbundling dynamic capabilities: An exploratory study of continuous product innovation
Get PDFIn order to understand better the organizational sources of continuous innovation, this paper provides an inâdepth analysis of Oticon A/S, a leading company in the hearingâaid industry, which showed an impressive ability to develop new products in the nineties. Findings highlight that dynamic capabilities are made up of: knowledge creation and absorption, knowledge integration and knowledge reconfiguration. Discussion links the findings to previous literature and shows how these knowledgeâbased processes are all based on a coherent mix of organizational resources
Spectroscopic properties and radiation damage investigation of a diamond based Schottky diode for ion-beam therapy microdosimetry
Get PDFIn this work, a detailed analysis of the properties of a novel microdosimeter based on a synthetic single crystal diamond is reported. Focused ion microbeams were used to investigate the device spectropscopic properties as well as the induced radiation damageeffects. A diamond based Schottky diode was fabricated by chemical vapor deposition with a very thin detecting region, about 400ânm thick (approximately 1.4âÎŒm water equivalent thickness), corresponding to the typical size in microdosimetric measurements. A 200âĂâ200âÎŒm2 square metallic contact was patterned on the diamond surface by standard photolithography to define the sensitive area. Experimental measurements were carried out at the Ruder BoĆĄkovicâČ Institute microbeam facility using 4âMeV carbon and 5âMeV silicon ions. Ion beam induced charge maps were employed to characterize the microdosimeter response in terms of its charge collection properties. A stable response with no evidence of polarization or memory effects was observed up to the maximum investigated ion beam flux of about 1.7âĂâ109 ions·cmâ2·sâ1. A homogeneity of the response about 6% was found over the sensitive region with a well-defined confinement of the response within the active area. Tests of the radiation damageeffect were performed by selectively irradiating small areas of the device with different ion fluences, up to about 1012 ions/cm2. An exponential decrease of the charge collection efficiency was observed with a characteristic decay constant of about 4.8 MGy and 1 MGy for C and Si ions, respectively. The experimental data were analyzed by means of GEANT4 Monte Carlo simulations. A direct correlation between the diamond damaging effect and the Non Ionizing Energy Loss (NIEL) fraction was found. In particular, an exponential decay of the charge collection efficiency with an exponential decay as a function of NIEL is observed, with a characteristic constant of about 9.3 kGy-NIEL for both carbon and silicon ions
Photo-physical properties of He-related color centers in diamond
Get PDFDiamond is a promising platform for the development of technological
applications in quantum optics and photonics. The quest for color centers with
optimal photo-physical properties has led in recent years to the search for
novel impurity-related defects in this material. Here, we report on a
systematic investigation of the photo-physical properties of two He-related
(HR) emission lines at 535 nm and 560 nm created in three different diamond
substrates upon implantation with 1.3 MeV He+ ions and subsequent annealing.
The spectral features of the HR centers were studied in an "optical grade"
diamond substrate as a function of several physical parameters, namely the
measurement temperature, the excitation wavelength and the intensity of
external electric fields. The emission lifetimes of the 535 nm and 560 nm lines
were also measured by means of time-gated photoluminescence measurements,
yielding characteristic decay times of (29 +- 5) ns and (106 +- 10) ns,
respectively. The Stark shifting of the HR centers under the application of an
external electrical field was observed in a CVD diamond film equipped with
buried graphitic electrodes, suggesting a lack of inversion symmetry in the
defects' structure. Furthermore, the photoluminescence mapping under 405 nm
excitation of a "detector grade" diamond sample implanted at a 1x1010 cm-2 He+
ion fluence enabled to identify the spectral features of both the HR emission
lines from the same localized optical spots. The reported results provide a
first insight towards the understanding of the structure of He-related defects
in diamond and their possible utilization in practical applicationsComment: 9 pages, 3 figure
Glucocerebrosidase deficiency promotes release of α-synuclein fibrils from cultured neurons
Get PDFMutations in the GBA gene, which encodes the lysosomal enzyme glucocerebrosidase (GCase), are the most important genetic risk factor for Parkinson disease (PD). GCase activity is also decreased in sporadic PD brains and with normal aging. Loss of GCase activity impairs the autophagy lysosomal pathway resulting in increased α-synuclein (α-syn) levels. Furthermore, elevated α-syn results in decreased GCase activity. While the role of α-syn in PD remains unclear, evidence indicates that aggregated α-syn fibrils are a pathogenic species in PD, passing between neurons and inducing endogenous native α-syn to aggregate; spreading pathology through the brain. We have investigated if preformed α-syn fibrils (PFFs) impair GCase activity in mouse cortical neurons and differentiated dopaminergic cells, and whether GCase deficiency in these models increased the transfer of α-syn pathology to naĂŻve cells. Neurons treated with PFFs induced endogenous α-syn to become insoluble and phosphorylated at Ser129 to a greater extent than monomeric α-syn-treatment. PFFs, but not monomeric α-syn, inhibited lysosomal GCase activity in these cells and induced the unfolded protein response. Neurons in which GCase was inhibited by conduritol ÎČ-epoxide did not increase the amount of insoluble monomeric α-syn or its phosphorylation status. Instead the release of α-syn fibrils from GCase deficient cells was significantly increased. Co-culture studies showed that the transfer of α-syn pathology to naĂŻve cells was greater from GCase deficient cells. This study suggests that GCase deficiency increases the spread of α-syn pathology and likely contributes to the earlier age of onset and increased cognitive decline associated with GBA-PD
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