| 1. |
- Chen, Min Rui, et al.
(författare)
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Effects of nanoparticles on hydraulic cavitation
- 2018
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Ingår i: XI International Conference on Computational Heat, Mass and Momentum Transfer (ICCHMT 2018). - : EDP Sciences. ; 240
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Konferensbidrag (refereegranskat)abstract
- When liquids flowing through a throttling element, such as a perforated plate, the velocity increases and the pressure decreases. If the pressure is below the saturated vapor pressure, the liquid will vaporize into small bubbles, which is called hydraulic cavitation. In fact, vaporization nucleus is another crucial condition for vaporizing. The nanoparticles contained in the nanofluids play a significant role in vaporization of liquids. In this paper, the effects of the nanoparticles on hydraulic cavitation are investigated. Firstly, a geometric model of a pipe channel equipped with a perforated plate is established. Then with different nanoparticle volume fractions and diameters, the nanofluids flowing through the channel is numerically simulated based on a validated numerical method. The operation conditions, such as the temperature and the pressure ratio of inlet to outlet, are the considered variables. As a significant parameter, cavitation numbers under different operation conditions are achieved to investigate the effects of nanoparticles on hydraulic cavitation. Meanwhile, the contours are extracted to research the distribution of bubbles for further investigation. This study is of interests for researchers working on hydraulic cavitation or nanofluids.
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| 2. |
- Karpaty, Patrik, et al.
(författare)
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Foreign direct investment and productivity spillovers in Swedish manufacturing
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Based on a panel of data for Swedish manufacturing firms in 1990-2000, this paper finds strong evidence for the existence of positive spillover effects from inward FDI. The presence of foreign ownership in the same industry and region seems to enhance the total factor productivity of domestic firms. Moreover, the size of these FDI spillover effects seems to depend both on the nationality of the foreign MNF as well as on the absorptive capacity of the domestic firm, measured by its own R&D. It appears that this positive relationship between foreign presence and productivity cannot be explained as a consequence of reverse causality, i.e that FDI is attracted to highly productive regions and industries.
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| 3. |
- Vernet, Erik, et al.
(författare)
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Affibody-mediated retention of the epidermal growth factor receptor in the secretory compartments leads to inhibition of phosphorylation in the kinase domain
- 2009
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Ingår i: New biotechnology. - : Elsevier BV. - 1871-6784. ; 25:6, s. 417-423
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal activity of the epidermal growth factor receptor (EGFR) is associated with various cancer-related processes and motivates the search for strategies that can selectively block EGFR signalling. In this study, functional knockdown of EGFR was achieved through expression of an affibody construct, (Z(EGFR:1907))(2)-KDEL, with high affinity for EGFR and extended with the amino acids KDEL to make it resident in the secretory compartments. Expression of (Z(EGFR:1907))(2)-KDEL resulted in 80% reduction of the cell surface level of EGFR, and fluorescent staining for EGFR and the (Z(EGFR:1907))(2)-KDEL construct showed overlapping intracellular localisation. Immunocapture of EGFR from cell lysates showed that an intracellular complex between EGFR and the affibody construct had been formed, further indicating a specific interaction between the affibody construct and EGFR. Surface depletion of EGFR led to a dramatic decrease in the amount of kinase domain phosphorylated EGFR, coincident with a significant decrease in the proliferation rate.
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| 4. |
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| 5. |
- Xie, Ling, et al.
(författare)
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3D electron tomography analysis of silicon nanoparticles in SiC matrices by quantitative determination of EELS plasmon intensities
- 2014
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Konferensbidrag (refereegranskat)abstract
- Silicon nanoparticles (NPs) embedded in insulating or semiconducting matrices has attracted much interest for the third generation of photovoltaics, “all-Si” tandem solar cells. This study is to show how silicon NPs are distributed in 3D on a silicon carbide thin film using the electron tomography technique in the transmission electron microscopy (TEM). [2]We first have assessed Si NPs distributions in such SiCx sample with a low degree of crystalline using bright field (BF) TEM tomography (figure 1) and found an average nearest neighbor spacing of two NPs of about 12nm. For more crystalline NPs, the projection requirement is no more fulfilled and only those Si NPs that are both crystalline and oriented to a Bragg reflection are detectable. [3] Therefore, in this case, conventional BF TEM signal is unsuitable for electron tomography and we applied spectrum imaging (SI) techniques: EELS SI imaging and EFTEM SI imaging. Since Si and SiCx have different plasmon energies, [4] we can extract Si plasmon and SiCx plasmon images from the spectrum images. We observed that only a proper fit of the plasmon spectrum with subsequent extraction of Si and SiCx plasmon images results in the correct Si ad SiCx distribution (figures 2 and 3), whereas just EFTEM images taken from windows around the Si and the SiC plasmon energy resulted in overlaps in the image. For both, STEM and EFTEM SI signals, in figure 2 and 3, we are able to detect the entire population of NPs. In figure 3, the stripes like contrast inside of crystalline NPs shown in the BF TEM image persist in plasmon images. This is due to parallel beam illumination in EFTEM SI mode thus making the STEM SI imaging more suitable for tomography of these NPs. In Figure 2, for STEM SI, the contrast evolution during the tilting is thickness dependent, thicker part of the sample gives stronger contrast in the extracted plasmon images, and this nonlinear thickness effect can be corrected by introducing attenuation coefficient. [5]In summary, to study the 3D distribution of Si NPs in SiCx matrix, we compared three signals from BF TEM, STEM and EFTEM SI signals. In order to overcome the non-linearity of contrast change during the tilting process, STEM-SI signal in combination with quantitative treatment of the plasmon spectra shows clear Si NP contrasts and overcomes limits set by the projection requirement.[1] S. Perraud et al., Phys. Status Solidi A, 1–9 (2012).[2] J. Frank, Electron Tomography: Three Dimensional Imaging with the Transmission ElectronMicroscope, Plenum, New York, London, 1992.[3] P. A. Midgley et al., Ultramicroscopy 96 (2003) 413.[4] R.F. Egerton, Electron Energy-Loss Spectroscopy in the Electron Microscope, 420, 2011.[5] W. Van den Broek et al. Ultramicroscopy 116 (2012) 8–12
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| 6. |
- Xie, Li, et al.
(författare)
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A system-on-chip and paper-based inkjet printed electrodes for a hybrid wearable bio-sensing system
- 2012
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Ingår i: Engineering in Medicine and Biology Society (EMBC), 2012 Annual International Conference of the IEEE. - : IEEE. - 9781424441198 ; , s. 5026-5029
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Konferensbidrag (refereegranskat)abstract
- This paper presents a hybrid wearable bio-sensing system, which combines traditional small-area low-power and high-performance System-on-Chip (SoC), flexible paper substrate and cost-effective Printed Electronics. Differential bio-signals are measured, digitized, stored and transmitted by the SoC. The total area of the chip is 1.5 × 3.0 mm2. This enables the miniaturization of the wearable system. The electrodes and interconnects are inkjet printed on paper substrate and the performance is verified in in-vivo tests. The quality of electrocardiogram signal sensed by printed electrodes is comparable with commercial electrodes, with noise level slightly increased. The paper-based inkjet printed system is flexible, light and thin, which makes the final system comfortable for end-users. The hybrid bio-sensing system offers a potential solution to the next generation wearable healthcare technology.
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| 7. |
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| 8. |
- Xie, Long, et al.
(författare)
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Baseline structural MRI and plasma biomarkers predict longitudinal structural atrophy and cognitive decline in early Alzheimer’s disease
- 2023
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Ingår i: Alzheimer's Research and Therapy. - 1758-9193. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Crucial to the success of clinical trials targeting early Alzheimer’s disease (AD) is recruiting participants who are more likely to progress over the course of the trials. We hypothesize that a combination of plasma and structural MRI biomarkers, which are less costly and non-invasive, is predictive of longitudinal progression measured by atrophy and cognitive decline in early AD, providing a practical alternative to PET or cerebrospinal fluid biomarkers. Methods: Longitudinal T1-weighted MRI, cognitive (memory-related test scores and clinical dementia rating scale), and plasma measurements of 245 cognitively normal (CN) and 361 mild cognitive impairment (MCI) patients from ADNI were included. Subjects were further divided into β-amyloid positive/negative (Aβ+/Aβ−)] subgroups. Baseline plasma (p-tau181 and neurofilament light chain) and MRI-based structural medial temporal lobe subregional measurements and their association with longitudinal measures of atrophy and cognitive decline were tested using stepwise linear mixed effect modeling in CN and MCI, as well as separately in the Aβ+/Aβ− subgroups. Receiver operating characteristic (ROC) analyses were performed to investigate the discriminative power of each model in separating fast and slow progressors (first and last terciles) of each longitudinal measurement. Results: A total of 245 CN (35.0% Aβ+) and 361 MCI (53.2% Aβ+) participants were included. In the CN and MCI groups, both baseline plasma and structural MRI biomarkers were included in most models. These relationships were maintained when limited to the Aβ+ and Aβ− subgroups, including Aβ− CN (normal aging). ROC analyses demonstrated reliable discriminative power in identifying fast from slow progressors in MCI [area under the curve (AUC): 0.78–0.93] and more modestly in CN (0.65–0.73). Conclusions: The present data support the notion that plasma and MRI biomarkers, which are relatively easy to obtain, provide a prediction for the rate of future cognitive and neurodegenerative progression that may be particularly useful in clinical trial stratification and prognosis. Additionally, the effect in Aβ− CN indicates the potential use of these biomarkers in predicting a normal age-related decline.
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| 9. |
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| 10. |
- Xie, Ling, 1982-, et al.
(författare)
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Electron tomography analysis of 3D interfacial nanostructures appearing in annealed Si rich SiC films
- 2017
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Ingår i: Nanoscale. - : ROYAL SOC CHEMISTRY. - 2040-3364 .- 2040-3372. ; 9:20, s. 6703-6710
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Tidskriftsartikel (refereegranskat)abstract
- The optical and electrical properties of Si rich SiC (SRSC) solar cell absorber layers will strongly depend on interfacial layers between the Si and the SiC matrix and in this work, we analyze hitherto undiscovered interfacial layers. The SRSC thin films were deposited using a plasma-enhanced chemical vapor deposition (PECVD) technique and annealed in a nitrogen environment at 1100 degrees C. The thermal treatment leads to metastable SRSC films spinodally decomposed into a Si-SiC nanocomposite. After the thermal treatment, the coexistence of crystalline Si and SiC nanostructures was analysed by high resolution transmission electron microscopy (HRTEM) and electron diffraction. From the quantitative extraction of the different plasmon signals from electron energy-loss spectra, an additional structure, amorphous SiC (a-SiC) was found. Quantitative spectroscopic electron tomography was developed to obtain three dimensional (3D) plasmonic maps. In these 3D spectroscopic maps, the Si regions appear as network structures inside the SiC matrix where the a-SiC appears as an interfacial layer separating the matrix and Si network. The presence of the a-SiC interface can be explained in the framework of the nucleation and growth model.
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