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- Lars, Herrnsdorf, et al.
(författare)
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Point Dose Profile Measurments using Solid State Detectors in Characterization of Computed Tomograhy Systems
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elesevier. - 0168-9002 .- 1872-9576. ; 607:1, s. 223-225
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Tidskriftsartikel (refereegranskat)abstract
- Existing solid-state detectors for point dose measurements are typically mounted in a package with a high Z material acting as the back contact causing unsymmetrical response. In the Computed Tomography (CT) dose profile application this is a major drawback. A new silicon detector has been constructed without this disturbing element. The new detector has been mounted in a cylindrical tube and its characteristics are presented in this paper. The conclusion is that this new detector design is a major improvement for correct dose and dose profile measurements in CT systems.
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| 3. |
- Stattin, Eva-Lena, et al.
(författare)
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Founder mutations characterise the mutation panorama in 200 Swedish index cases referred for Long QT syndrome genetic testing
- 2012
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Ingår i: BMC Cardiovascular Disorders. - : BioMed Central. - 1471-2261 .- 1471-2261. ; 12, s. 95-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Long QT syndrome (LQTS) is an inherited arrhythmic disorder characterised by prolongation of the QT interval on ECG, presence of syncope and sudden death. The symptoms in LQTS patients are highly variable, and genotype influences the clinical course. This study aims to report the spectrum of LQTS mutations in a Swedish cohort.Methods: Between March 2006 and October 2009, two hundred, unrelated index cases were referred to the Department of Clinical Genetics, Umea University Hospital, Sweden, for LQTS genetic testing. We scanned five of the LQTS-susceptibility genes (KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2) for mutations by DHPLC and/or sequencing. We applied MLPA to detect large deletions or duplications in the KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 genes. Furthermore, the gene RYR2 was screened in 36 selected LQTS genotype-negative patients to detect cases with the clinically overlapping disease catecholaminergic polymorphic ventricular tachycardia (CPVT).Results: In total, a disease-causing mutation was identified in 103 of the 200 (52%) index cases. Of these, altered exon copy numbers in the KCNH2 gene accounted for 2% of the mutations, whereas a RYR2 mutation accounted for 3% of the mutations. The genotype-positive cases stemmed from 64 distinct mutations, of which 28% were novel to this cohort. The majority of the distinct mutations were found in a single case (80%), whereas 20% of the mutations were observed more than once. Two founder mutations, KCNQ1 p.Y111C and KCNQ1 p.R518*, accounted for 25% of the genotype-positive index cases. Genetic cascade screening of 481 relatives to the 103 index cases with an identified mutation revealed 41% mutation carriers who were at risk of cardiac events such as syncope or sudden unexpected death.Conclusion: In this cohort of Swedish index cases with suspected LQTS, a disease-causing mutation was identified in 52% of the referred patients. Copy number variations explained 2% of the mutations and 3 of 36 selected cases (8%) harboured a mutation in the RYR2 gene. The mutation panorama is characterised by founder mutations (25%), even so, this cohort increases the amount of known LQTS-associated mutations, as approximately one-third (28%) of the detected mutations were unique.
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| 4. |
- Stattin, Eva-Lena, et al.
(författare)
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Genetic screening in sudden cardiac death in the young can save future lives
- 2016
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Ingår i: International Journal of Legal Medicine. - : Springer Science and Business Media LLC. - 0937-9827 .- 1437-1596. ; 130:1, s. 59-66
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Tidskriftsartikel (refereegranskat)abstract
- Autopsy of sudden cardiac death (SCD) in the young shows a structurally and histologically normal heart in about one third of cases. Sudden death in these cases is believed to be attributed in a high percentage to inherited arrhythmogenic diseases. The purpose of this study was to investigate the value of performing post-mortem genetic analysis for autopsy-negative sudden unexplained death (SUD) in 1 to 35 year olds. From January 2009 to December 2011, samples from 15 cases suffering SUD were referred to the Department of Clinical Genetics, UmeAyen University Hospital, Sweden, for molecular genetic evaluation. PCR and bidirectional Sanger sequencing of genes important for long QT syndrome (LQTS), short QT syndrome (SQTS), Brugada syndrome type 1 (BrS1), and catecholaminergic polymorphic ventricular tachycardia (CPVT) (KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2, and RYR2) was performed. Multiplex ligation-dependent probe amplification (MLPA) was used to detect large deletions or duplications in the LQTS genes. Six pathogenic sequence variants (four LQTS and two CPVT) were discovered in 15 SUD cases (40 %). Ten first-degree family members were found to be mutation carriers (seven LQTS and three CPVT). Cardiac ion channel genetic testing in autopsy-negative sudden death victims has a high diagnostic yield, with identification of the disease in 40 % of families. First-degree family members should be offered predictive testing, clinical evaluation, and treatment with the ultimate goal to prevent sudden death.
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| 5. |
- Zettergren, Henning, et al.
(författare)
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Are single C-60 fullerenes dielectric or metallic?
- 2012
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 14:47, s. 16360-16364
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Tidskriftsartikel (refereegranskat)abstract
- We present analytical solutions for the interaction energies between a static point charge and a metal- or a dielectric sphere. These solutions include polarization effects to infinite orders in the inverse of the distance between the point charge and the spheres. Further, we present Density Functional Theory (DFT) calculations of interaction energies for a point charge in ranges of fixed positions outside a neutral or a singly charged C-60 molecule. Based on these DFT results, we conclude that the metal sphere model describes the electronic response of the C60 molecule much better than the dielectric sphere model. These findings are particularly important for calculations of energy barriers for charge transfer in reactions involving C60 molecules. The metal- and dielectric models should further be useful for descriptions of, for example, the polarizabilities of and interactions with conducting and insulating spherical clusters or particles.
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