| 1. |
- Dyrskjøt, Lars, et al.
(författare)
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Gene expression signatures predict outcome in non-muscle-invasive bladder carcinoma : a multicenter validation study
- 2007
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 13:12, s. 3545-3551
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Clinically useful molecular markers predicting the clinical course of patients diagnosed with non–muscle-invasive bladder cancer are needed to improve treatment outcome. Here, we validated four previously reported gene expression signatures for molecular diagnosis of disease stage and carcinoma in situ (CIS) and for predicting disease recurrence and progression. Experimental Design: We analyzed tumors from 404 patients diagnosed with bladder cancer in hospitals in Denmark, Sweden, England, Spain, and France using custom microarrays. Molecular classifications were compared with pathologic diagnosis and clinical outcome. Results: Classification of disease stage using a 52-gene classifier was found to be highly significantly correlated with pathologic stage (P < 0.001). Furthermore, the classifier added information regarding disease progression of Ta or T1 tumors (P < 0.001). The molecular 88-gene progression classifier was highly significantly correlated with progression-free survival (P < 0.001) and cancer-specific survival (P = 0.001). Multivariate Cox regression analysis showed the progression classifier to be an independently significant variable associated with disease progression after adjustment for age, sex, stage, grade, and treatment (hazard ratio, 2.3; P = 0.007). The diagnosis of CIS using a 68-gene classifier showed a highly significant correlation with histopathologic CIS diagnosis (odds ratio, 5.8; P < 0.001) in multivariate logistic regression analysis. Conclusion: This multicenter validation study confirms in an independent series the clinical utility of molecular classifiers to predict the outcome of patients initially diagnosed with non–muscle-invasive bladder cancer. This information may be useful to better guide patient treatment.
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| 2. |
- Kalered, Emil, et al.
(författare)
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On the work function and the charging of small (r ≤ 5 nm) nanoparticles in plasmas
- 2017
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Ingår i: Physics of Plasmas. - : American Institute of Physics (AIP). - 1070-664X .- 1089-7674. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- The growth of nanoparticles (NPs) in plasmas is an attractive technique where improved theoretical understanding is needed for quantitative modeling. The variation of the work function W with size for small NPs, rNP≤ 5 nm, is a key quantity for modeling of three NP charging processes that become increasingly important at a smaller size: electron field emission, thermionic electron emission, and electron impact detachment. Here we report the theoretical values of the work function in this size range. Density functional theory is used to calculate the work functions for a set of NP charge numbers, sizes, and shapes, using copper for a case study. An analytical approximation is shown to give quite accurate work functions provided that rNP > 0.4 nm, i.e., consisting of about >20 atoms, and provided also that the NPs have relaxed close to spherical shape. For smaller sizes, W deviates from the approximation, and also depends on the charge number. Some consequences of these results for nanoparticle charging are outlined. In particular, a decrease in W for NP radius below about 1 nm has fundamental consequences for their charge in a plasma environment, and thereby on the important processes of NP nucleation, early growth, and agglomeration.
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| 3. |
- Minea, T. M., et al.
(författare)
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Kinetics of plasma species and their ionization in short-HiPIMS by particle modeling
- 2014
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 255, s. 52-61
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Tidskriftsartikel (refereegranskat)abstract
- The ionization efficiency of High Power Impulse Magnetron Sputtering (HiPIMS) discharges is the key parameter leading to (i) gas ion production and consequently controlling the sputtering effectiveness and (ii) sputtered vapor ionization, self-consistently linked to self-sputtering and thin film properties. To study the HiPIMS discharge time dependent two dimensional Particle in Cell (2D PIC) modelling coupled with Monte Carlo treatment of the plasma kinetics is discussed in terms of numerical scheme and stability criteria. The first microscopic results are presented for very short pulses (similar to 5 mu s) using superimposed DC pre-ionization. During this modeled HiPIMS short-pulse the plasma density increases at least two orders of magnitude driven by the pulse voltage, which also continues for a short time in the afterglow. During the pulse voltage plateau, the plasma potential shows a linear dependency going away from the target with two slopes over two space regions. First region is very narrow (<0.5 mm), corresponding to the cathode sheath in front of the race-track, while the second region, much larger, corresponds to the pre-sheath or Ionization Region (IR). Modeling results show an increasing electric field in the sheath with the voltage rise of the pulse, while it stays almost constant in the IR, corresponding to about 150 Vcm(-1), in agreement with reported probe measurements. The local electron energy distribution functions in the IR and further out in the Diffusion Region (DR) are very different. IR electrons are much more energetic compared to the ones found in the DR, which have an important low energy population as a result of the ionization processes. The transport of sputtered metal vapor from the target is simulated by 3D Monte Carlo (MC) modeling, in the intermediary pressure range - between ballistic and diffusive. Using the self-consistent output of plasma density maps from PLC with MC transport of sputtered vapor including their possible ionization when they cross the HiPIMS dense plasma, it is possible to estimate the metal ionization fraction, found here slightly lower than in previous reported works.
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| 4. |
- Pilch, Iris, et al.
(författare)
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Nanoparticle growth by collection of ions : orbital motion limited theory and collision-enhanced collection
- 2016
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Ingår i: Journal of Physics D. - : Institute of Physics Publishing (IOPP). - 0022-3727 .- 1361-6463. ; 49:39
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Tidskriftsartikel (refereegranskat)abstract
- The growth of nanoparticles in plasma is modeled for situations where the growth is mainly due to the collection of ions of the growth material. The model is based on the classical orbit motion limited (OML) theory with the addition of a collision-enhanced collection (CEC) of ions. The limits for this type of model are assessed with respect to three processes that are not included: evaporation of the growth material, electron field emission, and thermionic emission of electrons. It is found that both evaporation and thermionic emission can be disregarded below a temperature that depends on the nanoparticle material and on the plasma parameters; for copper in our high-density plasma this limit is about 1200 K. Electron field emission can be disregarded above a critical nanoparticle radius, in our case around 1.4 nm. The model is benchmarked, with good agreement, to the growth of copper nanoparticles from a radius of 5 nm-20 nm in a pulsed power hollow cathode discharge. Ion collection by collisions contributes with approximately 10% of the total current to particle growth, in spite of the fact that the collision mean free path is four orders of magnitude longer than the nanoparticle radius.
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