| 1. |
- Lundström, Robert, et al.
(författare)
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Fatigue modeling as related to flexible pavement design - State of the art
- 2007
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Ingår i: International Journal on Road Materials and Pavement Design. - : Informa UK Limited. - 1468-0629 .- 2164-7402. ; 8:2, s. 165-205
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Forskningsöversikt (refereegranskat)abstract
- A literature study of rheological and fatigue modeling of asphalt mixtures is presented. Theoretical aspects on structural modeling, rheological behavior and the fatigue integration in design procedures are reviewed In principle, pavement design methods can be categorized in three broad groups: empirical, semi-mechanistic and fully mechanistic methods. Pavement design is generally performed using semi-mechanistic methods comprising analytical or numerical structural response models and deterioration modeling based on transfer functions and shift factors. In the case of fatigue deterioration, several approaches have been elaborated e.g. classical models, fracture mechanics and damage mechanics. The approaches differ regarding theoretical foundation and evaluation methods used. Recognizing significant limitations concerning theoretical basis as well as lack of empirical support for current design methods, a shift in paradigm from semi-empirical methods towards more advanced fully mechanistic methods have been initiated. According to this approach, improved pavements are achieved by appropriate design methods which are capable of predicting fatigue resistance in the actual pavement environment, and thus taking into account complex stress conditions, influence of temperature and material characteristics, such as aging and healing.
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| 2. |
- Lundström, Robert, et al.
(författare)
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Influence of pavement materials on field performance : Evaluation of rutting on flexible semi-rigid and rigid test sections after 7 years of service
- 2009
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Ingår i: International Journal on Road Materials and Pavement Design. - : Informa UK Limited. - 1468-0629 .- 2164-7402. ; 10:4, s. 689-713
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents results obtained so far from a Swedish full-scale test, comprising in total 19 different rigid, semi-rigid and flexible test stretches. The purpose is to compare rutting performance of the different pavement categories and types using extensive laboratory tests and field measurements after seven years of trafficking. The rigid pavements withstand rutting better than the two other pavement categories due to comparably small abrasion and negligible permanent deformation. The semi-rigid pavements show less rutting than the flexible pavements, which primarily is the result of the negligible permanent deformation in the cement bound layers. Even though the rigid pavements show very small rutting, it is probably not the main distress type and the primary trigger for maintenance activities for this pavement type. In the case of semi-flexible and flexible pavements, both laboratory tests and field measurements indicate that significantly improved rutting performance can be obtained using appropriate asphalt mixtures manufactured using wear-resistant aggregates and stiff binder.
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| 3. |
- Auer, Renate, et al.
(författare)
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Measuring the Signs of H-1(alpha) Chemical Shift Differences Between Ground and Excited Protein States by Off-Resonance Spin-Lock R-1 rho NMR Spectroscopy
- 2009
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Ingår i: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 131:31, s. 10832-10833
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion NMR profiles provides the kinetics and thermodynamics of millisecond-time-scale exchange processes involving the interconversion of populated ground and invisible excited states. In addition, the absolute values of chemical, shift differences between NMR probes in the exchanging states, vertical bar Delta(pi)vertical bar, are also extracted. Herein, we present a simple experiment for obtaining the sign of H-1(alpha) Delta(pi) values by measuring off-resonance H-1(alpha) decay rates, R-1 rho, using weak proton spin-lock fields. A pair of R-1 rho values is measured with a spin-lock field applied vertical bar Delta omega vertical bar downfield and upfield of the major-state peak. In many cases, these two relaxation rates differ substantially, with the larger one corresponding to the case where the spin-lock field coincides with the resonance frequency of the probe in the minor state. The utility of the methodology is demonstrated first on a system involving protein ligand exchange and subsequently on an SH3 domain exchanging between a folded state and its on-pathway folding intermediate. With this experiment, it thus becomes possible to determine H-1(alpha) chemical shifts of the invisible excited state, which can be used as powerful restraints in defining the structural properties of these elusive conformers.
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| 4. |
- Bjorklund, Robert, et al.
(författare)
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Automatic optimization of experimental conditions for fast evaluation of diagnostic tests using ubiquitous instrumentation
- 2008
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 134:1, s. 199-205
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Tidskriftsartikel (refereegranskat)abstract
- Rapid quantitative determinations of creatinine, potassium and glucose, all important parameters in routine medical diagnostics, are demonstrated using a computer screen photo-assisted technique (CSPT). CSPT uses regular computer screens as light sources and web cameras as imaging detectors for supporting optical evaluations of diverse character. The ubiquity and versatility of the setup, makes CSPT an attractive candidate for point of care determinations. A robust procedure for the automatic selection of experimental conditions in CSPT evaluation, including camera channels and illuminating colors that minimize the measuring time up to 5 times is described. The method utilizes the correlation between experimental conditions and classification scores, obtained under a generic 50 color training session, to extract measuring sequences as short as 9 s. The extracted measuring conditions automatically adapted to the different tests provided a general, practical and fast approach for CSPT optimization in real scenarios. © 2008 Elsevier B.V. All rights reserved.
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| 5. |
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| 6. |
- Eriksson, Mats, et al.
(författare)
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Event Detection in Crisis Management Systems
- 2009
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Ingår i: Procedia Chemistry. - : Elsevier. - 1876-6196. ; 1:1, s. 1055-1058
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Tidskriftsartikel (refereegranskat)abstract
- The EVENT project concerns drinking water surveillance and includes sensors and algorithms that detect anomalies in the drinking water properties, communication of the evaluated sensor data to a crises management system and presentation of information that is relevant for the end users of the crises management system. We have chosen to focus on a sensor technique based on an "electronic tongue", since this robust type of non-selective sensor, can detect a plurality of anomalies without the need of a specific sensor for each type of event. Measurements of natural variations and contamination events are presented and discussed.
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| 7. |
- Eriksson, Therese, 1979-
(författare)
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Organelle movement in melanophores: Effects of Panax ginseng, ginsenosides and quercetin
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Panax ginseng is a traditional herb that has been used for over 2000 years to promote health and longevity. Active components of ginseng include ginsenosides, polysaccharides, flavonoids, polyacetylenes, peptides, vitamins, phenols and enzymes, of which the ginsenosides are considered to be the major bioactive constituents. Although widely used, the exact mechanisms of ginseng and its compounds remain unclear. In this thesis we use melanophores from Xenopus laevis to investigate the effects of Panax ginseng extract G115 and its constituents on organelle transport and signalling. Due to coordinated bidirectional movement of their pigmented granules (melanosomes), in response to defined chemical signals, melanophores are capable of fast colour changes and provide a great model for the study of intracellular transport. The movement is regulated by alterations in cyclic adenosine 3’:5’-monophosphate (cAMP) concentration, where a high or low level induce anterograde (dispersion) or retrograde (aggregation) transport respectively, resulting in a dark or light cell. Here we demonstrate that Panax ginseng and its constituents ginsenoside Rc and Rd and flavonoid quercetin induce a concentration-dependent anterograde transport of melanosomes. The effect of ginseng is shown to be independent of cAMP changes and protein kinase A activation. Upon incubation of melanophores with a combination of Rc or Rd and quercetin, a synergistic increase in anterograde movement was seen, indicating cooperation between the ginsenoside and flavonoid parts of ginseng. Protein kinase C (PKC) inhibitor Myristoylated EGF-R Fragment 651-658 decreased the anterograde movement stimulated by ginseng and ginsenoside Rc and Rd. Moreover, ginseng, but not ginsenosides or quercetin, stimulated an activation of 44/42-mitogen activated protein kinase (MAPK), previously shown to be involved in both aggregation and dispersion of melanosomes. PKC-inhibition did not affect the MAPK-activation, suggesting a role for PKC in the ginseng- and ginsenoside-induced dispersion but not as an upstream activator of MAPK.
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| 8. |
- Klenkar, Goran, et al.
(författare)
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Piezo Dispensed Microarray of Multivalent Chelating Thiols for Dissecting Complex Protein-Protein Interactions
- 2006
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 78:11, s. 3643-3650
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Tidskriftsartikel (refereegranskat)abstract
- The fabrication of a novel biochip, designed for dissection of multiprotein complex formation, is reported. An array of metal chelators has been produced by piezo dispensing of a bis-nitrilotriacetic acid (bis-NTA) thiol on evaporated gold thin films, prestructured with a microcontact printed grid of eicosanethiols. The bis-NTA thiol is mixed in various proportions with an inert, tri(ethylene glycol) hexadecane thiol, and the thickness and morphological homogeneity of the dispensed layers are characterized by imaging ellipsometry before and after back-filling with the same inert thiol and subsequent rinsing. It is found that the dispensed areas display a monotonic increase in thickness with increasing molar fraction of bis-NTA in the dispensing solution, and they are consistently a few Ångströms thicker than those prepared at the same molar fraction by solution self-assembly under equilibrium-like conditions. The bulkiness of the bis-NTA tail group and the short period of time available for chemisorption and in-plane organization of the dispensed thiols are most likely responsible for the observed difference in thickness. Moreover, the functional properties of this biochip are demonstrated by studying multiple protein−protein interactions using imaging surface plasmon resonance. The subunits of the type I interferon receptor are immobilized as a composition array determined by the surface concentration of bis-NTA in the array elements. Ligand dissociation kinetics depends on the receptor surface concentration, which is ascribed to the formation of a ternary complex by simultaneous interaction of the ligand with the two receptor subunits. Thus, multiplexed monitoring of binding phenomena at various compositions (receptor densities) offers a powerful tool to dissect protein−protein interactions.
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| 9. |
- Lundström, Robert, et al.
(författare)
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Fatigue characterization of asphalt concrete using Schapery's work potential model
- 2006
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Ingår i: Nordic Rheology Society.
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Konferensbidrag (refereegranskat)abstract
- This paper presents an investigation ofSchapery´s work potential theory (WPT), aconstitutive viscoelastic continuum damagemodel, applied to characterize fatigue behaviorof asphalt concrete. Although someanomalies were noted, results indicate thatthe model is applicable to characterizefatigue-related damage growth at differentloading modes, excitation amplitudes andtemperatures.
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| 10. |
- Winquist, Fredrik, et al.
(författare)
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An electronic tongue in the dairy industry
- 2005
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 111, s. 299-304
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Tidskriftsartikel (refereegranskat)abstract
- The concept of electronic tongues or taste sensors has developed rapidly during recent years due to their large potential. They are based on electrochemical sensors combined with multivariate data analysis. Voltammetric electronic tongues have proven valuable in many applications. Due to their ruggedness and simplicity, they have been found especially suitable for on-line monitoring of industrial processes. A voltammetric electronic tongue, specially designed for use in the dairy industry is described. It consisted of four working electrodes (gold, platinum, rhodium and stainless steel), embedded in PEEK (TM). It was mounted in a housing of stainless steel, which was inserted in the process line for direct on-line measurements. The voltammetric electronic tongue was used to follow different sources of milk coming into the process and to monitor the cleaning process. (c) 2005 Elsevier B.V. All rights reserved.
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