| 1. |
- Bergstrand, Helena, et al.
(författare)
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Analys av elektriskt fält och celltransport vid sårläkning
- 2008
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Ingår i: Tsunami. - 1651-5803. ; :1
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Sårläkning är ett komplext problem som än idag inte är helt utrett. Genom historien har många både bra och dåliga metoder utvecklats och prövats. Mycket är känt om sårläkningens olika faser, men för att ytterligare förstå problemet krävs en fullständig kännedom om alla olika faktorer som påverkar kroppens läkningsprocess. Under de sanaste årtiondena har en diskussion uppstått angående elektriska fälts inverkan på sårläkning. I huden finns naturligt ett elektriskt fält som resultat av jontransport mellan hudens olika cellager. Experiment har visat att cellers rörelse stimuleras av ett yttre pålagt fält liknande det som finns i huden. Denna rapport tar fram en modell för att bveräkna det kroppsegna fältet och använda detta till att, utifrån hypotesen att cellers hastighet är proportionell mot den lokala elektriska fältstyrkan, simulera hur cellar tar sig in i sår. Analysen av det kroppsgena elektriska fältet bygger på experimentella data. Då huden liknas vid en elektrolyt stämmer det analytiskt framtagna fältet väl överens med experimentella data. Den numeriska simuleringen av celltransporten sker enligt en rörelseekvation som grundar sig på en förflyttningsterm istället för en diffusionsterm, vilket är det som används i alla tidigare sårläkningsmodeller som studerats. Simuleringarna visar i vilken utsträckning denna representation av verkligheten kan användas för att beskriva sårläkningsprocesser i hornhinnan.
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| 2. |
- Carpatorea, Iulian, 1982-, et al.
(författare)
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APPES Maps as Tools for Quantifying Performance of Truck Drivers
- 2014
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Ingår i: Proceedings of the 2014 International Conference on Data Mining, DMIN'14. - USA : CSREA Press. - 9781601323132 ; , s. 10-16
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Konferensbidrag (refereegranskat)abstract
- Understanding and quantifying drivers’ influence on fuel consumption is an important and challenging problem. A number of commonly used approaches are based on collection of Accelerator Pedal Position - Engine Speed (APPES) maps. Up until now, however, most publicly available results are based on limited amounts of data collected in experiments performed under well-controlled conditions. Before APPES maps can be considered a reliable solution, there is a need to evaluate the usefulness of those models on a larger and more representative data.In this paper we present analysis of APPES maps that were collected, under actual operating conditions, on more than 1200 trips performed by a fleet of 5 Volvo trucks owned by a commercial transporter in Europe. We use Gaussian Mixture Models to identify areas of those maps that correspond to different types of driver behaviour, and investigate how the parameters of those models relate to variables of interest such as vehicle weight or fuel consumption.
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| 3. |
- Carpatorea, Iulian, 1982-, et al.
(författare)
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Learning of Aggregate Features for Comparing Drivers Based on Naturalistic Data
- 2016
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Ingår i: Proceedings. - Los Alamitos, CA : IEEE Computer Society. - 9781509061662 ; , s. 1067-1072
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Konferensbidrag (refereegranskat)abstract
- Fuel used by heavy duty trucks is a major cost for logistics companies, and therefore improvements in this area are highly desired. Many of the factors that influence fuel consumption, such as the road type, vehicle configuration or external environment, are difficult to influence. One of the most under-explored ways to lower the costs is training and incentivizing drivers. However, today it is difficult to measure driver performance in a comprehensive way outside of controlled, experimental setting.This paper proposes a machine learning methodology for quantifying and qualifying driver performance, with respect to fuel consumption, that is suitable for naturalistic driving situations. The approach is a knowledge-based feature extraction technique, constructing a normalizing fuel consumption value denoted Fuel under Predefined Conditions (FPC), which captures the effect of factors that are relevant but are not measured directly.The FPC, together with information available from truck sensors, is then compared against the actual fuel used on a given road segment, quantifying the effects associated with driver behavior or other variables of interest. We show that raw fuel consumption is a biased measure of driver performance, being heavily influenced by other factors such as high load or adversary weather conditions, and that using FPC leads to more accurate results. In this paper we also show evaluation the proposed method using large-scale, real-world, naturalistic database of heavy-duty vehicle operation.
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| 4. |
- Carpatorea, Iulian, 1982-, et al.
(författare)
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Towards Data Driven Method for Quantifying Performance of Truck Drivers
- 2014
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Ingår i: The SAIS Workshop 2014 Proceedings. - : Swedish Artificial Intelligence Society (SAIS). ; , s. 133-142
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Konferensbidrag (refereegranskat)abstract
- Understanding factors that influence fuel consumption is a very important task both for the OEMs in the automotive industry and for their customers. There is a lot of knowledge already available concerning this topic, but it is poorly organized and often more anecdotal than rigorously verified. Nowadays, however, rich datasets from actual vehicle usage are available and a data-mining approach can be used to not only validate earlier hypotheses, but also to discover unexpected influencing factors.In this paper we particularly focus on analyzing how behavior of drivers affects fuel consumption. To this end we introduce a concept of “Base Value”, a number that incorporates many constant, unmeasured factors. We show our initial results on how it allows us to categorize driver’s performance more accurately than previously used methods. We present a detailed analysis of 32 trips by Volvo trucks that we have selected from a larger database. Those trips have a large overlap in the route traveled, of over 100 km, and at the same time exhibit different driver and fuel consumption characteristics.
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| 5. |
- Elmer, Eskil, et al.
(författare)
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Regulation of neuronal nitric oxide synthase mRNA levels in rat brain by seizure activity
- 1996
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Ingår i: NeuroReport. - 1473-558X. ; 7:7, s. 1335-1335
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Tidskriftsartikel (refereegranskat)abstract
- The regulation of neuronal nitric oxide synthase (NOS) mRNA levels during kindling epileptogenesis in the rat brain was investigated using in situ hybridization. Following 40 rapidly recurring seizures evoked by hippocampal stimulations, NOS mRNA expression decreased by 56% in the dentate granule cell layer (maximum at 2 h) and increased by 420,105 and 1260% in the CA1 and CA3 pyramidal layers and piriform cortex, respectively (maximum at 12-24 h). Gene expression had returned to control levels after one week. The presumed alterations of nitric oxide production, following the changes in NOS mRNA shown here, may modulate synaptic function during kindling development, and could influence neuronal vulnerability after epileptic insults.
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| 6. |
- Elmer, Steven J, et al.
(författare)
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Fatigue is specific to working muscles : no cross-over during single-leg cycling in trained cyclists
- 2013
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 113:2, s. 479-488
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Tidskriftsartikel (refereegranskat)abstract
- Fatigue induced via a maximal isometric contraction of a single limb muscle group can evoke a "cross-over" of fatigue that reduces voluntary muscle activation and maximum isometric force in the rested contralateral homologous muscle group. We asked whether a cross-over of fatigue also occurs when fatigue is induced via high-intensity endurance exercise involving a substantial muscle mass. Specifically, we used high-intensity single-leg cycling to induce fatigue and evaluated associated effects on maximum cycling power (P max) in the fatigued ipsilateral leg (FATleg) as well as the rested contralateral leg (RESTleg). On separate days, 12 trained cyclists performed right leg P max trials before and again 30 s, 3, 5, and 10 min after a cycling time trial (TT, 10 min) performed either with their right or left leg. Fatigue was estimated by comparing exercise-induced changes in P max and maximum handgrip isometric force (F max). Mean power produced during the right and left leg TTs did not differ (203 ± 8 vs. 199 ± 8 W). Compared to pre-TT, FATleg P max was reduced by 22 ± 3 % at 30 s post-TT and remained reduced by 9 ± 2 % at 5 min post-TT (both P < 0.05). Despite considerable power loss in the FATleg, post-TT RESTleg P max (596–603 W) did not differ from pre-TT values (596 ± 35 W). There were no alterations in handgrip F max (529–547 N). Our data suggest that any potential cross-over of fatigue, if present at all, was not sufficient to measurably compromise RESTleg P max in trained cyclists. These results along with the lack of changes in handgrip F max indicate that impairments in maximal voluntary neuromuscular function were specific to working muscles.
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| 7. |
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| 8. |
- Hansson, Magnus, et al.
(författare)
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Calcium-induced generation of reactive oxygen species in brain mitochondria is mediated by permeability transition.
- 2008
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Ingår i: Free Radical Biology & Medicine. - : Elsevier BV. - 0891-5849. ; 45, s. 284-294
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondrial uptake of calcium in excitotoxicity is associated with subsequent increase in reactive oxygen species (ROS) generation and delayed cellular calcium deregulation in ischemic and neurodegenerative insults. The mechanisms linking mitochondrial calcium uptake and ROS production remain unknown but activation of the mitochondrial permeability transition (mPT) may be one such mechanism. In the present study, calcium increased ROS generation in isolated rodent brain and human liver mitochondria undergoing mPT despite an associated loss of membrane potential, NADH and respiration. Unspecific permeabilization of the inner mitochondrial membrane by alamethicin likewise increased ROS independently of calcium, and the ROS increase was further potentiated if NAD(H) was added to the system. Importantly, calcium per se did not induce a ROS increase unless mPT was triggered. Twenty-one cyclosporin A analogs were evaluated for inhibition of calcium-induced ROS and their efficacy clearly paralleled their potency of inhibiting mPT-mediated mitochondrial swelling. We conclude that while intact respiring mitochondria possess powerful antioxidant capability, mPT induces a dysregulated oxidative state with loss of GSH- and NADPH-dependent ROS detoxification. We propose that mPT is a significant cause of pathological ROS generation in excitotoxic cell death.
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| 9. |
- Hansson, Magnus, et al.
(författare)
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Powerful cyclosporin inhibition of calcium-induced permeability transition in brain mitochondria.
- 2003
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Ingår i: Brain Research. - 1872-6240. ; 960:1-2, s. 99-111
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Tidskriftsartikel (refereegranskat)abstract
- The mitochondrial permeability transition (mPT) is considered to be an important mediator of apoptosis and necrosis, and is specifically blocked by cyclosporin A (CsA). CsA has been shown to exert a potent neuroprotective action in vivo when allowed to cross the blood–brain barrier in various animal models of acute neurological insults and neurodegenerative disease. The neuroprotective effect of CsA is considered to be mediated through specific inhibition of the mitochondrial permeability transition pore (mPTP) and through inhibition of neuronal calcineurin activity. Characterization of mPT has mainly been performed in liver and heart mitochondria, and some brain studies have reported a decreased inhibitory effect of CsA and questioned the importance of mPT in brain-derived mitochondria. We have used the de-energized model of swelling to examine the mPT in brain-derived non-synaptosomal mitochondria. Ca2+-induced swelling was evaluated by electron microscopy and by measurement of spectrophotometric alterations in light scattering. Permeability transition was readily induced in a majority of the mitochondria at a wide range of Ca2+ levels and was powerfully inhibited by CsA with a half-maximal effect at not, vert, similar23 nM CsA. The swelling kinetics and CsA effects were comparable to previous findings in de-energized liver and heart mitochondria. Careful characterization of mPT and CsA effects in brain-derived mitochondria is the first step in evaluating newly developed CsA analogues capable of crossing the blood–brain barrier and preferentially entering the brain. The importance of CsA causing a shift of the mitochondrial sensitivity to Ca2+ in neurological disorders is discussed.
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| 10. |
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