| 1. |
- Abadir Guirgis, Georg, 1988-, et al.
(författare)
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Simulatorbaserad utbildning i ERTMS : utvärdering av utbildning och träning för lokförare i VTI:s tågsimulator
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Detta notat presenterar en studie för att utvärdera VTI:s tågsimulator för träning och utbildning i ERTMS (European Rail Traffic Management System) för lokförare. Resultaten visar att både lärare och elever är mycket positiva till den simulatorbaserade träningen och mycket tyder på att teori och simulatorträning som varvas ger bäst resultat. På sikt ska de större järnvägsstråken i Sverige utrustas med ERTMS. Detta kommer kräva stora utbildningsinsatser för Sveriges cirka 3 500 lokförare. Det är orealistiskt att dessa ska utbildas på riktiga spår och det finns ett behov av en mer realistisk ERTMS-simulator än den ERSA-simulator som Trafikverket erbjuder idag. Studiens syfte var därför att utvärdera VTI:s tågsimulator, dels jämfört med European Rail Software Applications (ERSA) simulatorn, dels för att studera två olika sätt att kombinera teoretisk utbildning med praktisk träning i simulator. Tre olika grupper jämfördes: Teoretisk utbildning i ERTMS kombinerat med träning i ERSA-simulator (grupp 0), teoretisk utbildning i ERTMS som avslutades med träning i VTI-simulatorn (grupp 1) och teoretisk utbildning i ERTMS som till viss del varvades med träning i VTI-simulatorn (grupp 2). Grupp 1 och 2 fick avsluta utbildningen med ett teoretiskt prov och ett praktiskt körprov i simulator. Grupp 0 endast fick göra det teoretiska provet.
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| 2. |
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| 3. |
- Aftab, A., et al.
(författare)
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Novel zinc oxide nanoparticles deposited acrylamide composite used for enhancing the performance of water-based drilling fluids at elevated temperature conditions
- 2016
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Ingår i: Journal of Petroleum Science and Engineering. - : Elsevier. - 0920-4105 .- 1873-4715. ; 146, s. 1142-1157
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional nano-micron composite compared to single nano-sphere materials revealed wide applications to enhance the physical and chemical stability of base fluids. Therefore, it can be a possible solution for the improvement of the rheological properties and shale inhibition characteristics of conventional water-based drilling fluid (WBDF). The primary goal of the study was to investigate the effects zinc oxide nanoparticles-acrylamide composite termed as ZnO-Am composite over rheological and shale swelling behavior of conventional WBDF. Herein, ZnO-Am composite was synthesized and successfully characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermalgravimeteric analysis (TGA), scanning electron microscope (SEM) and field emission electron microscope (FESEM). Results revealed that the rheological properties such as 10-min gel strength (10-min GS), apparent viscosity (AV), and plastic vicscocity (PV) were slightly increased and obtained within operating range at 150 degrees F by adding the synthesized composite in conventional WBDF. Lubricity was improved by 25% at 150 degrees F. API filtrate loss volume was reduced by 14%. Elevated temperature and pressure (ETP) filtrate loss volume (500 psi, 250 degrees F) was slightly minimized. Shale swelling was merely reduced from 16% to 9%. These findings will contribute to enhance the oil and gas well drilling operations.
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| 4. |
- Aftab, Muhammad Usman, et al.
(författare)
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Towards A Distributed Ledger Based Verifiable Trusted Protocol for VANET
- 2021
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Ingår i: 2021 International Conference on Digital Futures and Transformative Technologies, ICoDT2 2021. - : Institute of Electrical and Electronics Engineers Inc.. - 9781665412858
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Konferensbidrag (refereegranskat)abstract
- To ensure traffic safety and proper operation of vehicular networks, safety messages or beacons are periodically broadcasted in Vehicular Adhoc Networks (VANETs) to neighboring nodes and road side units (RSU). Thus, authenticity and integrity of received messages along with the trust in source nodes is crucial and highly required in applications where a failure can result in life-threatening situations. Several digital signature based approaches have been described in literature to achieve the authenticity of these messages. In these schemes, scenarios having high level of vehicle density are handled by RSU where aggregated signature verification is done. However, most of these schemes are centralized and PKI based where our goal is to develop a decentralized dynamic system. Along with authenticity and integrity, trust management plays an important role in VANETs which enables ways for secure and verified communication. A number of trust management models have been proposed but it is still an ongoing matter of interest, similarly authentication which is a vital security service to have during communication is not mostly present in the literature work related to trust management systems. This paper proposes a secure and publicly verifiable communication scheme for VANET which achieves source authentication, message authentication, non repudiation, integrity and public verifiability. All of these are achieved through digital signatures, Hash Message Authentication Code (HMAC) technique and logging mechanism which is aided by blockchain technology.
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| 5. |
- Aftab, Obaid, 1984-, et al.
(författare)
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Detection of cell aggregation and altered cell viability by automated label-free video microscopy : A promising alternative to endpoint viability assays in high throughput screening
- 2015
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Ingår i: Journal of Biomolecular Screening. - : Elsevier BV. - 1087-0571 .- 1552-454X. ; 20:3, s. 372-381
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Tidskriftsartikel (refereegranskat)abstract
- Automated phase-contrast video microscopy now makes it feasible to monitor a high-throughput (HT) screening experiment in a 384-well microtiter plate format by collecting one time-lapse video per well. Being a very cost-effective and label-free monitoring method, its potential as an alternative to cell viability assays was evaluated. Three simple morphology feature extraction and comparison algorithms were developed and implemented for analysis of differentially time-evolving morphologies (DTEMs) monitored in phase-contrast microscopy videos. The most promising layout, pixel histogram hierarchy comparison (PHHC), was able to detect several compounds that did not induce any significant change in cell viability, but made the cell population appear as spheroidal cell aggregates. According to recent reports, all these compounds seem to be involved in inhibition of platelet-derived growth factor receptor (PDGFR) signaling. Thus, automated quantification of DTEM (AQDTEM) holds strong promise as an alternative or complement to viability assays in HT in vitro screening of chemical compounds.
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| 6. |
- Aftab, Obaid, 1984-, et al.
(författare)
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Label-free detection and dynamic monitoring of drug-induced intracellular vesicle formation enabled using a 2-dimensional matched filter
- 2014
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8627 .- 1554-8635. ; 10:1, s. 57-69
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of vesicle formation and degradation is a central issue in autophagy research and microscopy imaging is revolutionizing the study of such dynamic events inside living cells. A limiting factor is the need for labeling techniques that are labor intensive, expensive, and not always completely reliable. To enable label-free analyses we introduced a generic computational algorithm, the label-free vesicle detector (LFVD), which relies on a matched filter designed to identify circular vesicles within cells using only phase-contrast microscopy images. First, the usefulness of the LFVD is illustrated by presenting successful detections of autophagy modulating drugs found by analyzing the human colorectal carcinoma cell line HCT116 exposed to each substance among 1266 pharmacologically active compounds. Some top hits were characterized with respect to their activity as autophagy modulators using independent in vitro labeling of acidic organelles, detection of LC3-II protein, and analysis of the autophagic flux. Selected detection results for 2 additional cell lines (DLD1 and RKO) demonstrate the generality of the method. In a second experiment, label-free monitoring of dose-dependent vesicle formation kinetics is demonstrated by recorded detection of vesicles over time at different drug concentrations. In conclusion, label-free detection and dynamic monitoring of vesicle formation during autophagy is enabled using the LFVD approach introduced.
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| 7. |
- Ahlin, Gustav, 1977-, et al.
(författare)
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Genotype-dependent effects of inhibitors of the organic cation transporter, OCT1: : predictions of metformin interactions
- 2011
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Ingår i: The Pharmacogenomics Journal. - : Springer Science and Business Media LLC. - 1470-269X .- 1473-1150. ; 11:6, s. 400-411
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Tidskriftsartikel (refereegranskat)abstract
- Common genetic variants of the liver-specific human organic cation transporter 1 (OCT1; SLC22A1) have reduced transport capacity for substrates such as the antidiabetic drug metformin. The effect of the reduced OCT1 function on drug interactions associated with OCT1 has not been investigated and was, therefore, the focus of the study presented here. HEK293 cells expressing human OCT1-reference or the variants R61C, V408M, M420del and G465R were first used to study the kinetics and inhibition pattern of the OCT1 substrate 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP(+)). In the second part OCT1-mediated (14)C-metformin uptake was studied in the presence of drugs administered concomitantly with metformin. Transport studies using ASP(+) showed that the function of the variants decreased in the following order: OCT1-reference = V408M = M420del >R61C > >G465R. Variants M420del and R61C were more sensitive to drug inhibition, with IC(50) values up to 23 times lower than those of the OCT1-reference. Uptake studies using (14)C-metformin were in qualitative agreement with those using ASP(+), with the exception that a larger reduction in transport capacity was observed for M420del. Concomitantly administered drugs, such as verapamil and amitriptyline, revealed potential drug-drug interactions at clinical plasma concentrations of metformin for OCT1-M420del.
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| 8. |
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| 9. |
- Amiri, Saeid, et al.
(författare)
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Assessing the coefficient of variations of chemical data using bootstrap method
- 2011
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Ingår i: Journal of Chemometrics. - : Wiley. - 0886-9383 .- 1099-128X. ; 25:6, s. 295-300
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Tidskriftsartikel (refereegranskat)abstract
- The coefficient of variation is frequently used in the comparison and precision of results with different scales. This work examines the comparison of the coefficient of variation without any assumptions about the underlying distribution. A family of tests based on the bootstrap method is proposed, and its properties are illustrated using Monte Carlo simulations. The proposed method is applied to chemical experiments with iid and non-iid observations.
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| 10. |
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