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81.
In order to understand better the organizational sources ofcontinuous innovation, this paper provides an in-depth analysisof Oticon A/S, a leading company in the hearing-aid industry,which showed an impressive ability to develop new products inthe nineties. Findings highlight that dynamic capabilities aremade up of: knowledge creation and absorption, knowledge integrationand knowledge reconfiguration. Discussion links the findingsto previous literature and shows how these knowledge-based processesare all based on a coherent mix of organizational resources.  相似文献   
82.
This paper reports the results of a comparison between two TiO2 photocatalysts that differ for particle size and absorption/scattering optical properties. The catalyst with larger particles and lower surface area performed better in the degradation of phenol than the specimen with smaller particles and larger surface area. Following carefully designed experiments, it is possible to assess the relative role of light absorption/scattering properties and catalyst-related efficiency by means of a basic kinetic model for the rate of photocatalytic reactions. Explicit relationships are derived in the framework of the steady-state approximation for the quantum yield as a function of one a-dimensional number collecting surface kinetic constants for charge carrier reactions at the interface, absorbed light and surface substrate concentrations. The dimensionality change to volume-defined quantities allows derivation of the explicit dependence of the quantum yield on substrate concentration and partition constants, catalyst concentration, and the rate of volumetric light absorption. Following this approach, the rate expression for slurry systems, valid in the absence of back reactions, is directly derived. Some further simplification of the rate equation for the case of low quantum yield regime leads to analytical relationships able to account for the dependence of the rate on catalyst concentration and absorbed light in the case of stirred and unstirred conditions. The reported properly designed experiments allow the estimation of catalyst-specific micro-kinetic constants.  相似文献   
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84.
In this pilot study, we compared two protocols for robot-based rehabilitation of upper limb in multiple sclerosis (MS): a protocol involving reaching tasks (RT) requiring arm transport only and a protocol requiring both objects' reaching and manipulation (RMT). Twenty-two MS subjects were assigned to RT or RMT group. Both protocols consisted of eight sessions. During RT training, subjects moved the handle of a planar robotic manipulandum toward circular targets displayed on a screen. RMT protocol required patients to reach and manipulate real objects, by moving the robotic arm equipped with a handle which left the hand free for distal tasks. In both trainings, the robot generated resistive and perturbing forces. Subjects were evaluated with clinical and instrumental tests. The results confirmed that MS patients maintained the ability to adapt to the robot-generated forces and that the rate of motor learning increased across sessions. Robot-therapy significantly reduced arm tremor and improved arm kinematics and functional ability. Compared to RT, RMT protocol induced a significantly larger improvement in movements involving grasp (improvement in Grasp ARAT sub-score: RMT 77.4%, RT 29.5%, p=0.035) but not precision grip. Future studies are needed to evaluate if longer trainings and the use of robotic handles would significantly improve also fine manipulation.  相似文献   
85.
Two-dimensional in vivo optical images of metacarpal bones of a human palm and in vitro images of turkey and chicken bones embedded in tissues were obtained in the near-infrared region using femtosecond pulse transillumination and picosecond electronic time-sliced detection technique. A small hole drilled in chicken bone and embedded in chicken breast tissue was imaged using early arriving light. Time-gated fluorescence images of an interior marrow region of a bone injected with a fluorescent dye were recorded. The techniques have potential for monitoring bone fracture, bone diseases such as, osteoporosis and arthritis, and diseases that originate in or affect bone marrow  相似文献   
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87.
In this paper, novel and previously proposed reversed nested Miller compensation (RNMC) networks are analyzed and compared, and their design equations are also presented. Hence, this paper is the natural extension of a previous paper by the authors (Int. J. Circ. Theor. Appl. 2008; 36 (1):53–80), where only the nested Miller compensation topologies were treated. In particular, a coherent and comprehensive analytical comparison of the RNMC topologies, including two new networks presented for the first time, is performed by means of the figure of merit that expresses a trade‐off among gain‐bandwidth product, load capacitance and total transconductance, for equal values of phase margin (Int. J. Circ. Theor. Appl. 2008; 36 (1):53–80). The analysis shows that there is no unique optimal solution among the RNMC topologies, as this depends on the load condition as well as on the relative transconductance magnitude of each amplifier stage. From this point of view, the proposed comparison also outlines useful design guidelines for the optimization of large‐signal and small‐signal performance. Simulations confirming the effectiveness of the proposed design methodology and analytical comparison are also included. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
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89.
Retinitis pigmentosa (RP) is a family of inherited disorders caused by the progressive degeneration of retinal photoreceptors. There is no cure for RP, but recent research advances have provided promising results from many clinical trials. All these therapeutic strategies are focused on preserving existing photoreceptors or substituting light-responsive elements. Vision recovery, however, strongly relies on the anatomical and functional integrity of the visual system beyond photoreceptors. Although the retinal structure and optic pathway are substantially preserved at least in early stages of RP, studies describing the visual cortex status are missing. Using a well-established mouse model of RP, we analyzed the response of visual cortical circuits to the progressive degeneration of photoreceptors. We demonstrated that the visual cortex goes through a transient and previously undescribed alteration in the local excitation/inhibition balance, with a net shift towards increased intracortical inhibition leading to improved filtering and decoding of corrupted visual inputs. These results suggest a compensatory action of the visual cortex that increases the range of residual visual sensitivity in RP.  相似文献   
90.
Malignant Pleural Mesothelioma (MPM) is a rare and aggressive neoplasm of the pleural mesothelium, mainly associated with asbestos exposure and still lacking effective therapies. Modern targeted biological strategies that have revolutionized the therapy of other solid tumors have not had success so far in the MPM. Combination immunotherapy might achieve better results over chemotherapy alone, but there is still a need for more effective therapeutic approaches. Based on the peculiar disease features of MPM, several strategies for local therapeutic delivery have been developed over the past years. The common rationale of these approaches is: (i) to reduce the risk of drug inactivation before reaching the target tumor cells; (ii) to increase the concentration of active drugs in the tumor micro-environment and their bioavailability; (iii) to reduce toxic effects on normal, non-transformed cells, because of much lower drug doses than those used for systemic chemotherapy. The complex interactions between drugs and the local immune-inflammatory micro-environment modulate the subsequent clinical response. In this perspective, the main interest is currently addressed to the development of local drug delivery platforms, both cell therapy and engineered nanotools. We here propose a review aimed at deep investigation of the biologic effects of the current local therapies for MPM, including cell therapies, and the mechanisms of interaction with the tumor micro-environment.  相似文献   
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