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- Van Guelpen, Bethany, et al.
(författare)
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One-carbon metabolism and CpG island methylator phenotype status in incident colorectal cancer : a nested case-referent study
- 2010
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 0957-5243 .- 1573-7225. ; 21:4, s. 557-566
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: We related prediagnostic plasma folate, vitamin B12, and total homocysteine concentrations, and the MTHFR 677C>T and 1298A>C polymorphisms, to the risk of colorectal cancer with and without the CpG island methylator phenotype (CIMP). METHODS: This was a nested case-referent study of 190 cases and double, matched referents from the large, population-based Northern Sweden Health and Disease Study. Using archival tumor tissue, promoter methylation in an eight-gene panel was analyzed by MethyLight. RESULTS: A reduced risk of CIMP-low/CIMP-high CRC (>/=1 gene methylated) was observed in subjects with very low plasma folate concentrations [multivariate odds ratio 2.96 (95% CI 1.24-7.08) for quintiles two to five versus one (lowest)]. With the exception of a reduced risk in MTHFR 677 TT-homozygotes, none of the other one-carbon variables were associated with the risk of CIMP-low/CIMP-high CRC. For CIMP-negative CRC, only the MTHFR polymorphisms were statistically significantly related to risk, inversely for 677C>T and positively for 1298A>C, but a tendency toward a reduced risk was observed in subjects with an adequate methyl availability, combining the plasma variables [multivariate odds ratio 0.61 (95% CI 0.32-1.15)]. CONCLUSION: Though limited by low power, these findings suggest the possibility of different roles for one-carbon metabolism in different pathways of colorectal tumorigenesis.
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- Adolfsson, J
(författare)
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Citing and endpoints
- 2022
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Ingår i: Scandinavian journal of urology. - : Medical Journals Sweden AB. - 2168-1813 .- 2168-1805. ; 56:3, s. 213-213
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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- Bonmann, Marlene, 1988
(författare)
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Effects of impurities on charge transport in graphene field-effect transistors
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In order to push the upper frequency limit of high speed electronics further, thereby extending the range of applications, new device technologies and materials are continuously investigated. The 2D material graphene, with its intrinsically extremely high room temperature charge carrier velocity, is regarded as a promising candidate to push the frequency limit even further. However, so far most fabrication processes unintentionally introduce impurities at the interface between graphene and adjacent materials, which affect the performance. Additionally, due to the lack of a band gap, the important power gain parameter, the maximum frequency of oscillation ($f_\text{max}$), is not impressively high. In this thesis, results of the studies of the effect of impurities on charge transport in a graphene field effect transistor (GFETs) are presented. This study was performed was done by, firstly, setting up a semi-empirical model describing the influence of impurities, i.e., interface states on capacitance and transfer characteristics at low electric fields and, secondly, by developing a method for studying the limiting mechanisms of the charge carrier velocity in the graphene channel at high electric fields. It was found that uncertainties in the material parameters of graphene, such as the Fermi velocity, hamper the possibility to find the correct mobility value by direct measurements on a GFET. Furthermore, it was shown that remote optical phonons limit the saturation velocity and charge carriers emitted from interface states at high fields are preventing the current to saturate and, hence, restricting $f_\text{max}$. By studying the effects and the limitations set by impurities and other parasitic effects in the GFET it is possible to clarify strategies for further development of GFETs towards reliable performance and higher $f_\text{max}$. As is shown in this work, it is necessary to develop a fabrication process which results in clean interfaces and adjacent materials with higher optical phonon energies than today.
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- Carlsson, Svante, et al.
(författare)
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On partitions and presortedness of sequences
- 1992
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Ingår i: Acta Informatica. - 0001-5903 .- 1432-0525. ; 29:3, s. 267-280
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Tidskriftsartikel (refereegranskat)abstract
- To take advantage of existing order in a sequence when sorting, we evaluate the quantity of this information by the minimal size of decomposition of the input sequence, particularly the minimal size of chain and of monotonic partitions. Some sorting strategies that are optimal with respect to these measures of presortedness are presented. The relationships between these new measures of presortedness and other known measures have also been explored. As an application, we carry out the optimality of an adaptive sorting algorithm Skiena'sMelsort. For some special partitioning strategies, we present two sorting algorithms based on Dijkstra'sSmoothsort. Moreover, the optimalities of these two algorithms are demonstrated. By examining the optimalities of sorting algorithms with respect to certain measures of presortedness, we also propose some optimal sorting strategies for one class of measures. Finally, we discuss other types of sorting problems, such as sorting multisets and topological sorting. In particular, we derive an optimal algorithm for sorting multisets and for finding the multiset sizes as well.
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| 7. |
- Jamizadeh, N, et al.
(författare)
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Endoscopic surveillance of Lynch syndrome at a highly specialized center in Sweden: An observational study of interval colorectal cancer and individual risk factors
- 2023
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Ingår i: Frontiers in oncology. - : Frontiers Media SA. - 2234-943X. ; 13, s. 1127707-
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Tidskriftsartikel (refereegranskat)abstract
- Lynch syndrome (LS) is the most common hereditary cause of colorectal cancer (CRC). In order to detect CRCs amongst LS patients, regular colonoscopies are recommended. However, an international agreement on an optimal surveillance interval has not yet been reached. In addition, few studies have investigated factors that could potentially increase the CRC risk amongst LS patients.AimsThe primary aim was to describe the frequency of CRCs detected during endoscopic surveillance and to estimate the interval from a clean colonoscopy to CRC detection amongst LS patients. The secondary aim was to investigate individual risk factors, including sex, LS genotype, smoking, aspirin use and body mass index (BMI), on CRC risk amongst patients that develop CRC before and during surveillance.Material and methodsClinical data and colonoscopy findings from 366 LS patients’ 1437 surveillance colonoscopies were collected from medical records and patient protocols. Logistic regression and Fisher’s exact test were used to investigate associations between individual risk factors and CRC development. Mann-Whitney U test was used to compare the distribution of TNM stages of CRC detected before surveillance and after index.ResultsCRC was detected in 80 patients before surveillance and in 28 patients during surveillance (10 at index and 18 after index). During the surveillance programme, CRC was detected within 24 months in 65% of the patients, and after 24 months within 35% of the patients. CRC was more common amongst men, previous and current smokers, and the odds of developing CRC also increased with an increasing BMI. CRCs were more often detected amongst MLH1 and MSH2 carriers during surveillance, compared to the other genotypes.ConclusionsWe found that 35% of the CRC cases detected during surveillance were found after 24 months. MLH1 and MSH2 carriers were at higher risk of developing CRC during surveillance. Additionally, men, current or previous smokers, and patients with a higher BMI were at higher risk of developing CRC. Currently, LS patients are recommended a “one-size-fits-all” surveillance program. The results support the development of a risk-score whereby individual risk factors should be taken into consideration when deciding on an optimal surveillance interval.
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- Vardanis, Yannis, et al.
(författare)
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Individuality in bird migration: routes and timing
- 2011
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Ingår i: Biology letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 7, s. 502-505
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Tidskriftsartikel (refereegranskat)abstract
- The exploration of animal migration has entered a new era with individual-based tracking during multiple years. Here, we investigated repeated migratory journeys of a long-distance migrating bird, the marsh harrier Circus aeruginosus, in order to analyse the variation within and between individuals with respect to routes and timing. We found that there was a stronger individual repeatability in time than in space. Thus, the annual timing of migration varied much less between repeated journeys of the same individual than between different individuals, while there was considerable variation in the routes of the same individual on repeated journeys. The overall contrast in repeatability between time and space was unexpected and may be owing to strong endogenous control of timing, while short-term variation in environmental conditions (weather and habitat) might promote route flexibility. The individual variation in migration routes indicates that the birds navigate mainly by other means than detailed route recapitulation based on landmark recognition.
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| 9. |
- Bratt, Ola, et al.
(författare)
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Palliativ cancervård är en betydande del av urologin. Studie av det sista levnadsåret för patienter som dog av urologisk cancer
- 2002
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Ingår i: Läkartidningen. - 0023-7205. ; 99:8, s. 765-770
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Tidskriftsartikel (refereegranskat)abstract
- A total of 330 in-patient episodes at the urology ward, with a mean duration of 9.8 days, were registered in a study of 100 patients who died from urological cancer. Twelve patients spent more than two months of their last year of life at the urology ward. As many as 82% of the admittances were on an emergency basis. A total of 101 operations were performed on 84 patients; 47 patients received palliative radiotherapy. This patient category needs a great deal of palliative care--at short notice--in order to get an optimal quality of life. Although many symptoms could have been alleviated outside hospital, the majority of patients needed specialised urological hospital care during their last year of life.
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| 10. |
- Allen, Mark, et al.
(författare)
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THE TWO-PHASE FRACTIONAL OBSTACLE PROBLEM
- 2015
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Ingår i: SIAM Journal on Mathematical Analysis. - : Society for Industrial and Applied Mathematics. - 0036-1410 .- 1095-7154. ; 47:3, s. 1879-1905
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Tidskriftsartikel (refereegranskat)abstract
- We study minimizers of the functional integral(+)(B1) vertical bar del u vertical bar(2)x(n)(a) dx + 2 integral(')(B1)(lambda + u(+) + lambda-u(-)) dx' for a is an element of (- 1, 1). The problem arises in connection with heat flow with control on the boundary. It can also be seen as a nonlocal analogue of the, by now well studied, two-phase obstacle problem. Moreover, when u does not change signs this is equivalent to the fractional obstacle problem. Our main results are the optimal regularity of the minimizer and the separation of the two free boundaries Gamma(+) = partial derivative'{u(center dot, 0) > 0} and Gamma(-) = partial derivative' {u(center dot, 0) < 0} when a >= 0.
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