| 1. |
- Vasan, Ramachandran S, et al.
(författare)
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Genetic variants associated with cardiac structure and function : a meta-analysis and replication of genome-wide association data
- 2009
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Ingår i: Journal of the American Medical Association (JAMA). - : American Medical Association (AMA). - 0098-7484 .- 1538-3598. ; 302:2, s. 168-178
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Echocardiographic measures of left ventricular (LV) structure and function are heritable phenotypes of cardiovascular disease. OBJECTIVE: To identify common genetic variants associated with cardiac structure and function by conducting a meta-analysis of genome-wide association data in 5 population-based cohort studies (stage 1) with replication (stage 2) in 2 other community-based samples. DESIGN, SETTING, AND PARTICIPANTS: Within each of 5 community-based cohorts comprising the EchoGen consortium (stage 1; n = 12 612 individuals of European ancestry; 55% women, aged 26-95 years; examinations between 1978-2008), we estimated the association between approximately 2.5 million single-nucleotide polymorphisms (SNPs; imputed to the HapMap CEU panel) and echocardiographic traits. In stage 2, SNPs significantly associated with traits in stage 1 were tested for association in 2 other cohorts (n = 4094 people of European ancestry). Using a prespecified P value threshold of 5 x 10(-7) to indicate genome-wide significance, we performed an inverse variance-weighted fixed-effects meta-analysis of genome-wide association data from each cohort. MAIN OUTCOME MEASURES: Echocardiographic traits: LV mass, internal dimensions, wall thickness, systolic dysfunction, aortic root, and left atrial size. RESULTS: In stage 1, 16 genetic loci were associated with 5 echocardiographic traits: 1 each with LV internal dimensions and systolic dysfunction, 3 each with LV mass and wall thickness, and 8 with aortic root size. In stage 2, 5 loci replicated (6q22 locus associated with LV diastolic dimensions, explaining <1% of trait variance; 5q23, 12p12, 12q14, and 17p13 associated with aortic root size, explaining 1%-3% of trait variance). CONCLUSIONS: We identified 5 genetic loci harboring common variants that were associated with variation in LV diastolic dimensions and aortic root size, but such findings explained a very small proportion of variance. Further studies are required to replicate these findings, identify the causal variants at or near these loci, characterize their functional significance, and determine whether they are related to overt cardiovascular disease.
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| 2. |
- Henriksson, Erik, 1982-
(författare)
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Compensating for Unreliable Communication Links in Networked Control Systems
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Control systems utilizing wireless sensor and actuator networks can be severely affectedby the properties of the communication links. Radio fading and interferencemay cause communication losses and outages in situations when the radio environmentis noisy and low transmission power is desirable. This thesis proposes amethod to compensate for such unpredictable losses of data in the feedback controlloop by introducing a predictive outage compensator (POC). The POC is a filter tobe implemented at the receiver sides of networked control systems where it generatesartificial samples when data are lost. If the receiver node does not receive thedata, the POC suggests a command based on the history of past data. It is shownhow to design, tune and implement a POC. Theoretical bounds and simulationresults show that a POC can improve the closed-loop control performance undercommunication losses considerably. We provide a deterministic and a stochasticmethod to synthesize POCs. Worst-case performance bounds are given that relatethe closed-loop performance with the complexity of the compensator. We also showthat it is possible to achieve good performance with a low-order implementationbased on Hankel norm approximation. Tradeoffs between achievable performance,communication loss length, and POC order are discussed. The results are illustratedon a simulated example of a multiple-tank process. The thesis is concludedby an experimental validation of wireless control of a physical lab process. Herethe controller and the physical system are separated geographically and interfacedthrough a wireless medium. For the remote control we use a hybrid model predictivecontroller. The results reflect the difficulties in wireless control as well as theyhighlight the flexibility and possibilities one obtains by using wireless instead of awired communication medium.
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| 3. |
- Lützhöft, Margareta, 1964, et al.
(författare)
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Shore-based pilotage: Pilot or autopilot? Piloting as a control problem
- 2009
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Ingår i: Journal of Navigation. - 0373-4633 .- 1469-7785. ; 62:3, s. 427-437
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Tidskriftsartikel (refereegranskat)abstract
- Remote, or shore-based, pilotage is an issue of some interest to the maritime community.When discussed, it is often in the context of new technology that in one way or the other issupposed to enhance piloting and enable ships to be piloted from the shore. This paper takesa different approach and instead looks at piloting as control of a complex system. Such anapproach makes it possible to identify a fundamental problem with remote pilotage. Theproblem, along with possible solutions, is presented and discussed.
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| 4. |
- Lützhöft, Margareta, 1964, et al.
(författare)
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Talk and trust before technology: First steps toward shore-based pilotage
- 2009
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Ingår i: RINA, Royal Institution of Naval Architects International Conference - Human Factors in Ship Design, Safety and Operation; London; United Kingdom; 25 February 2009 through 26 February 2009. - 9781905040551 ; , s. 47-53
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Konferensbidrag (refereegranskat)abstract
- Many instances discuss shore-based pilotage (SBP) as if it was only a question of putting technology to work. “The technology exists”, we are told. The Swedish Maritime Authority commissioned a “pilot study” to clarify definitions, technical and operational limitations, and to suggest a way forward regarding testing and simulations. Here, some of the results of the study are presented. It is for instance clear that in the minds of today’s pilots and VTS operators, technology is not a central aspect of their work. Communication and trust are two issues that both seen as far more important, and they are presented and discussed.
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| 5. |
- Mariscalco, Giovanni, et al.
(författare)
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Relationship between atrial histopathology and atrial fibrillation after coronary bypass surgery
- 2006
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Mosby Inc.. - 0022-5223 .- 1097-685X. ; 131:6, s. 1364-1372
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Postoperative atrial fibrillation is common after coronary surgery. The cellular condition of atrial myocytes might play a part in the postoperative development of atrial fibrillation. Our study aimed to investigate whether patients in whom postoperative atrial fibrillation develops show pre-existent alterations in histopathology of the right atrium and how such changes are expressed in relation to the use of cardiopulmonary bypass.METHODS: Seventy patients undergoing elective coronary revascularization were prospectively randomized to on-pump conventional surgery (conventional coronary artery bypass grafting, n = 35) or off-pump surgery on the beating heart (off-pump coronary artery bypass grafting, n = 35). Samples from the right atrial appendage were immediately collected after opening the pericardium. In the on-pump group samples were also taken after weaning from cardiopulmonary bypass. Focusing on degenerative alterations, histology was studied by means of light microscopy and for confirmation of particular findings by means of electronic microscopy.RESULTS: Twenty-two (31%) patients had postoperative atrial fibrillation, with the rate not being different between the off-pump coronary artery bypass grafting and conventional coronary artery bypass grafting groups (P = .797). Left atrial enlargement and inotropic requirement were related to atrial fibrillation. Interstitial fibrosis, vacuolization, and nuclear derangement of myocytes were the histologic abnormalities associated with the development of postoperative atrial fibrillation. However, in multivariate analysis fibrosis was confounded by myocyte vacuolization (P = .002) and nuclear derangement (P = .016), representing independent atrial fibrillation predictors. As expected, the conventional coronary artery bypass grafting and off-pump coronary artery bypass grafting groups showed similar histology, but more importantly, no atrial changes were detected in relation to cardiopulmonary bypass exposure in the conventional coronary artery bypass grafting group. Atrial histology showed degenerative changes that correlated with advanced age and left atrial enlargement.CONCLUSIONS: Our study supports the contention that atrial fibrillation after coronary surgery is associated with pre-existing histopathologic changes of the right atrium. Patients randomly allocated to off-pump coronary artery bypass grafting procedures showed a similar rate of atrial fibrillation and a similar relationship to atrial histology as did those exposed to cardiopulmonary bypass. Cardiopulmonary bypass did not cause additional changes in tested histology variables.
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| 6. |
- Marzorati, Mattia, et al.
(författare)
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Incorporation of primary amines into a polyester chain by a combination of chemical and lipase-catalyzed epsilon-caprolactone ring-opening processes
- 2007
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Ingår i: Advanced Synthesis and Catalysis. - : Wiley. - 1615-4150 .- 1615-4169. ; 349:12-nov, s. 1963-1968
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Tidskriftsartikel (refereegranskat)abstract
- A simple chemoenzymatic strategy for the incorporation of bioactive and suitably functionalized molecules into a polyester chain has been developed. The protocol involves first the reaction of a primary amine with E-caprolactone to give an amide carrying a terminal primary hydroxy group, followed by the enzymatic growth of the polymeric chain triggered by Novozym 435. This method is versatile and of different amines into polyesters, as has been shown with the model compounds benzylamine and tryptamine, the bioactive compound N-deacetylthiocolchicine and the functionalized propargylamine and tyramine.
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