Dynamical simulations of charged soliton transport in conjugated polymers with the inclusion of electron-electron interactions

We present numerical studies of the transport dynamics of a charged soliton in conjugated polymers under the influence of an external time-dependent electric field. All relevant electron-phonon and electron-electron interactions are nearly fully taken into account by simulating the monomer displacements with classical molecular dynamics (MD) and evolving the wavefunction for the $\pi$ electrons by virtue of the adaptive time-dependent density matrix renormalization group (TDDMRG) simultaneously and nonadiabatically. It is found that after a smooth turn-on of the external electric field the charged soliton is accelerated at first up to a stationary constant velocity as one entity consisting of both the charge and the lattice deformation. An ohmic region (6 mV/$\text{\AA}$ $\leq E_0\leq$ 12 mV/$\text{\AA}$) where the stationary velocity increases linearly with the electric field strength is observed. The relationship between electron-electron interactions and charged soliton transport is also investigated in detail. We find that the dependence of the stationary velocity of a charged soliton on the on-site Coulomb interactions $U$ and the nearest-neighbor interactions $V$ is due to the extent of delocalization of the charged soliton defect.Comment: 25 pages, 15 figure

Knowledge Management as a Strategic Tool to Foster Innovativeness of SMEs

This study examines the relationship between knowledge management (KM) (in terms of external acquisition and internal sharing) and innovation behavior. The concept of absorptive capacity and assumptions from the dynamic capabilities view underlie the proposed framework and hypotheses. The framework is empirically tested using a random sample of 649 Dutch small to medium sized enterprises (SMEs). Our empricial results indicate that external acquisition practices play a key role in fostering SMEs’ innovativeness while internal sharing practices do not appear to have a significant influence. External acquisition activity enhances a firm’s awareness of available knowledge opportunities. Firms which actively acquire external knowledge (regardless of the type of knowledge) may build a greater competitive dynamic capability to sense and seize business opportunities which in turn may lead to new or improved products or processes. We suggest that owners/entrepreneurs of SMEs and their firms will benefit in the long term if they strategically manage knowledge, especially using external acquisition practices

Knowledge Management in the SME and its Relationship to Strategy, Family Orientation and Organization Learning

In this study, we examine the prevalence of different KM practices and the organizational determinants of KM among SMEs by conducting a quantitative study of empirical data from nearly 500 Dutch SMEs. Our empirical results show that knowledge is managed in a people-based approach in SMEs. SMEs are most likely to acquire knowledge by staying in touch with professionals and experts outside the company and they incline to share knowledge and experience by talking to each other. Furthermore, KM is dependent on other organizational resources and processes. Organizational learning and competitive strategy with a formality approach are the positive determinants of KM while family orientation is a negative determinant of it. One of the challenges in the current study was to clearly distinguish, on an empirical basis, the previously defined concepts of knowledge management practices and organizational learning. Although in theory, they are distinct, the results of this study lead us to conclude that they may overlap in practice. In the conclusion, we recommend a learning-oriented knowledge management model for SMEs which combines aspects of the two literatures

What Turns Knowledge into Innovative Products? The Role of Entrepreneurship and Knowledge Spillovers

The knowledge spillover theory of entrepreneurship seeks to explain the fundamentals and consequences of entrepreneurship with respect to economic performance. This paper uses the knowledge spillover theory to explain different innovation outcomes. We hypothesize that a high rate of entrepreneurship facilitates the process of turning knowledge into new-to-the-market innovation but has no effect on the relationship between knowledge and new-to-the-firm innovation. Our results using European country-level and pooled OLS, fixed- and random-effects regressions show that a high rate of entrepreneurship increases the chances that knowledge will become new-to-the-market innovation. The findings highlight the importance of Schumpeterian entrepreneurship in the process of the commercialization of knowledge. We discuss the implications for entrepreneurship and innovation policy

The impact of Labour Relations on Innovative Output: An Exploration of Firm-level Data in the Netherlands

A growing literature on determinants of innovative per- formance focuses on factors such as market structure, firm size, (regional and international) knowledge spill- overs, R&D collaboration, conditions for appropriation of innovation benefits, and others. This paper contrib- utes to an aspect that is still sparsely explored: The im- pact of labour relations and Human Resource Manage- ment (HRM) practices on a firm’s innovative behaviour. Our empirical findings identify that active HRM policies, including job rotation, performance pay, and high qualification levels of personnel contribute positively to innovative performance

The Feasibility of Imaging Myocardial Ischemic/Reperfusion Injury Using \u3csup\u3e99m\u3c/sup\u3eTc-labeled Duramycin in a Porcine Model

When pathologically externalized, phosphatidylethanolamine (PE) is a potential surrogate marker for detecting tissue injuries. 99mTc-labeled duramycin is a peptide-based imaging agent that binds PE with high affinity and specificity. The goal of the current study was to investigate the clearance kinetics of 99mTc-labeled duramycin in a large animal model (normal pigs) and to assess its uptake in the heart using a pig model of myocardial ischemia–reperfusion injury. Methods The clearance and distribution of intravenously injected 99mTc-duramycin were characterized in sham-operated animals (n = 5). In a closed chest model of myocardial ischemia, coronary occlusion was induced by balloon angioplasty (n = 9). 99mTc-duramycin (10–15 mCi) was injected intravenously at 1 hour after reperfusion. SPECT/CT was acquired at 1 and 3 hours after injection. Cardiac tissues were analyzed for changes associated with acute cellular injuries. Autoradiography and gamma counting were used to determine radioactivity uptake. For the remaining animals, 99mTc-tetrafosamin scan was performed on the second day to identify the infarct site. Results Intravenously injected 99mTc-duramycin cleared from circulation predominantly via the renal/urinary tract with an α-phase half-life of 3.6 ± 0.3 minutes and β-phase half-life of 179.9 ± 64.7 minutes. In control animals, the ratios between normal heart and lung were 1.76 ± 0.21, 1.66 ± 0.22, 1.50 ± 0.20 and 1.75 ± 0.31 at 0.5, 1, 2 and 3 hours post-injection, respectively. The ratios between normal heart and liver were 0.88 ± 0.13, 0.80 ± 0.13, 0.82 ± 0.19 and 0.88 ± 0.14. In vivo visualization of focal radioactivity uptake in the ischemic heart was attainable as early as 30 min post-injection. The in vivo ischemic-to-normal uptake ratios were 3.57 ± 0.74 and 3.69 ± 0.91 at 1 and 3 hours post-injection, respectively. Ischemic-to-lung ratios were 4.89 ± 0.85 and 4.93 ± 0.57; and ischemic-to-liver ratios were 2.05 ± 0.30 to 3.23 ± 0.78. The size of 99mTc-duramycin positive myocardium was qualitatively larger than the infarct size delineated by the perfusion defect in 99mTc-tetrafosmin uptake. This was consistent with findings from tissue analysis and autoradiography. Conclusion 99mTc-duramycin was demonstrated, in a large animal model, to have suitable clearance and biodistribution profiles for imaging. The agent has an avid target uptake and a fast background clearance. It is appropriate for imaging myocardial injury induced by ischemia/reperfusion

Health-related quality of life as measured with EQ-5D among populations with and without specific chronic conditions: A population-based survey in Shaanxi province, China

© 2013 Tan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Introduction: The aim of this study was to examine health-related quality of life (HRQoL) as measured by EQ-5D and to investigate the influence of chronic conditions and other risk factors on HRQoL based on a distributed sample located in Shaanxi Province, China. Methods: A multi-stage stratified cluster sampling method was performed to select subjects. EQ-5D was employed to measure the HRQoL. The likelihood that individuals with selected chronic diseases would report any problem in the EQ-5D dimensions was calculated and tested relative to that of each of the two reference groups. Multivariable linear regression models were used to investigate factors associated with EQ VAS. Results: The most frequently reported problems involved pain/discomfort (8.8%) and anxiety/depression (7.6%). Nearly half of the respondents who reported problems in any of the five dimensions were chronic patients. Higher EQ VAS scores were associated with the male gender, higher level of education, employment, younger age, an urban area of residence, access to free medical service and higher levels of physical activity. Except for anemia, all the selected chronic diseases were indicative of a negative EQ VAS score. The three leading risk factors were cerebrovascular disease, cancer and mental disease. Increases in age, number of chronic conditions and frequency of physical activity were found to have a gradient effect. Conclusion: The results of the present work add to the volume of knowledge regarding population health status in this area, apart from the known health status using mortality and morbidity data. Medical, policy, social and individual attention should be given to the management of chronic diseases and improvement of HRQoL. Longitudinal studies must be performed to monitor changes in HRQoL and to permit evaluation of the outcomes of chronic disease intervention programs. © 2013 Tan et al.National Nature Science Foundation (No. 8107239