| 41. |
- Kyrø, Cecilie, et al.
(författare)
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Plasma Alkylresorcinols, Biomarkers of Whole-Grain Wheat and Rye Intake, and Incidence of Colorectal Cancer
- 2014
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press. - 0027-8874 .- 1460-2105. ; 106:1, s. djt352-
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Tidskriftsartikel (refereegranskat)abstract
- Background Few studies have investigated the association between whole-grain intake and colorectal cancer. Because whole-grain intake estimation might be prone to measurement errors, more objective measures (eg, biomarkers) could assist in investigating such associations. Methods The association between alkylresorcinols, biomarkers of whole-grain rye and wheat intake, and colorectal cancer incidence were investigated using prediagnostic plasma samples from colorectal cancer case patients and matched control subjects nested within the European Prospective Investigation into Cancer and Nutrition. We included 1372 incident colorectal cancer case patients and 1372 individual matched control subjects and calculated the incidence rate ratios (IRRs) for overall and anatomical subsites of colorectal cancer using conditional logistic regression adjusted for potential confounders. Regional differences (Scandinavia, the Mediterranean, Central Europe) were also explored. Results High plasma total alkylresorcinol concentration was associated with lower incidence of distal colon cancer; the adjusted incidence rate ratio of distal colon cancer for the highest vs lowest quartile of plasma total alkylresorcinols was 0.48 (95% confidence interval [CI] = 0.28 to 0.83). An inverse association between plasma total alkylresorcinol concentrations and colon cancer was found for Scandinavian participants (IRR per doubling = 0.83; 95% CI = 0.70 to 0.98). However, plasma total alkylresorcinol concentrations were not associated with overall colorectal cancer, proximal colon cancer, or rectal cancer. Plasma alkylresorcinols concentrations were associated with colon and distal colon cancer only in Central Europe and Scandinavia (ie, areas where alkylresorcinol levels were higher). Conclusions High concentrations of plasma alkylresorcinols were associated with a lower incidence of distal colon cancer but not with overall colorectal cancer, proximal colon cancer, and rectal cancer.
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| 42. |
- Köhler, Elof, 1980, et al.
(författare)
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Fabrication of High Temperature Thermoelectric Energy Harvesters for Wireless Sensors
- 2013
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 476:1, s. Art. no. 012036-
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Konferensbidrag (refereegranskat)abstract
- Implementing energy harvesters and wireless sensors in jet engines could simplify development and decrease costs. A thermoelectric energy harvester could be placed in the cooling channels where the temperature is between 500–900°C. This paper covers the synthesis of suitable materials and the design and fabrication of a thermoelectric module. The material choices and other design variables were done from an analytic model by numerical analysis. The module was optimized for 600–800°C with the materials Ba8Ga16Ge30 and La-doped Yb14MnSb11, both having the highest measured zT value in this region. The design goal was to be able to maintain a temperature gradient of at least 200°C with high power output. The La-doped Yb14MnSb11 was synthesized and its structure confirmed by x-ray diffraction. Measurement of properties of this material was not possible due to insufficient size of the crystals. Ba8Ga16Ge30 was synthesized and resulted in an approximated zT value of 0.83 at 700°C. Calculations based on a module with 17 couples gave a power output of 1100mW/g or 600mW/cm2 with a temperature gradient of 200K.
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| 43. |
- Köhler, Elof, 1980, et al.
(författare)
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High temperature energy harvester for wireless sensors
- 2014
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Ingår i: Smart Materials and Structures. - : IOP Publishing. - 0964-1726 .- 1361-665X. ; 23:9, s. Art. no. 095042-
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Tidskriftsartikel (refereegranskat)abstract
- Implementing energy harvesters and wireless sensors in jet engines will simplify development and decrease costs by reducing the need for cables. Such a device could include a small thermoelectric generator placed in the cooling channels of the jet engine where the temperature is between 500-900 degrees C. This paper covers the synthesis of suitable thermoelectric materials, design of module and proof of concept tests of a thermoelectric module. The materials and other design variables were chosen based on an analytic model and numerical analysis. The module was optimized for 600-800 degrees C with the thermoelectric materials n-type Ba8Ga16Ge30 and p-type La-doped Yb14MnSb11, both with among the highest reported figure-of-merit values, zT, for bulk materials in this region. The materials were synthesized and their structures confirmed by x-ray diffraction. Proof of concept modules containing only two thermoelectric legs were built and tested at high temperatures and under high temperature gradients. The modules were designed to survive an ambient temperature gradient of up to 200 degrees C. The first measurements at low temperature showed that the thermoelectric legs could withstand a temperature gradient of 123 degrees C and still be functional. The high temperature measurement with 800 degrees C on the hot side showed that the module remained functional at this temperature.
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| 44. |
- Leufkens, Anke M, et al.
(författare)
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Biomarkers of oxidative stress and risk of developing colorectal cancer : a cohort-nested case-control study in the European Prospective Investigation into Cancer and Nutrition
- 2012
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Ingår i: American Journal of Epidemiology. - : Oxford University Press (OUP). - 0002-9262 .- 1476-6256. ; 175:7, s. 653-663
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Tidskriftsartikel (refereegranskat)abstract
- Oxidative stress has been shown to play an important role in carcinogenesis, but prospective evidence for an association between biomarkers of oxidative stress and colorectal cancer (CRC) risk is limited. The authors investigated the association between prediagnostic serum levels of oxidative stress indicators (i.e., reactive oxygen metabolites (ROM) and ferric reducing ability of plasma (FRAP)) and CRC risk. This was examined in a nested case-control study (1,064 CRC cases, 1,064 matched controls) in the European Prospective Investigation Into Cancer and Nutrition cohort (1992-2003). Incidence rate ratios and 95% confidence intervals were calculated using conditional logistic regression analyses. ROM were associated with overall CRC risk (highest tertile vs. lowest: adjusted incidence rate ratio (IRR(adj)) = 1.91, 95% confidence interval (CI): 1.47, 2.48), proximal (IRR(adj) = 1.89, 95% CI: 1.06, 3.36) and distal (IRR(adj) = 2.31, 95% CI: 1.37, 3.89) colon cancer, and rectal cancer (IRR(adj) = 1.69, 95% CI: 1.05, 2.72). When results were stratified by tertile of follow-up time, the association remained significant only in participants with less than 2.63 years of follow-up (IRR(adj) = 2.28, 95% CI: 1.78, 2.94; P-heterogeneity < 0.01). FRAP was not associated with CRC risk. In conclusion, prediagnostic serum ROM levels were associated with increased risk of CRC. However, this association was seen only in subjects with relatively short follow-up, suggesting that the association results from production of reactive oxygen species by preclinical tumors.
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| 45. |
- Leufkens, Anke M, et al.
(författare)
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Educational level and risk of colorectal cancer in EPIC with specific reference to tumor location
- 2011
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Ingår i: International Journal of Cancer. - New York : Wiley-Blackwell. - 0020-7136 .- 1097-0215. ; 130:3, s. 622-630
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Tidskriftsartikel (refereegranskat)abstract
- Existing evidence is inconclusive on whether socioeconomic status (SES) and educational inequalities influence colorectal cancer (CRC) risk, and whether low or high SES/educational level is associated with developing CRC. The aim of our study was to investigate the relationship between educational level and CRC. We studied data from 400,510 participants in the EPIC (European Prospective Investigation into Cancer and Nutrition) study, of whom 2,447 developed CRC (colon: 1,551, rectum: 896, mean follow-up 8.3 years). Cox proportional hazard regression analysis stratified by age, gender and center, and adjusted for potential confounders were used to estimate hazard ratios (HR) and 95% confidence intervals (95%CI). Relative indices of inequality (RII) for education were estimated using Cox regression models. We conducted separate analyses for tumor location, gender and geographical region. Compared with participants with college/university education, participants with vocational secondary education or less had a nonsignificantly lower risk of developing CRC. When further stratified for tumor location, adjusted risk estimates for the proximal colon were statistically significant for primary education or less (HR 0.73, 95%CI 0.57–0.94) and for vocational secondary education (HR 0.76, 95%CI 0.58–0.98). The inverse association between low education and CRC risk was particularly found in women and Southern Europe. These associations were statistically significant for CRC, for colon cancer and for proximal colon cancer. In conclusion, CRC risk, especially in the proximal colon, is lower in subjects with a lower educational level compared to those with a higher educational level. This association is most pronounced in women and Southern Europe.
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| 46. |
- Ling, Agnes, 1976-, et al.
(författare)
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The intratumoural subsite and relation of CD8(+) and FOXP3(+) T lymphocytes in colorectal cancer provide important prognostic clues
- 2014
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Ingår i: British Journal of Cancer. - : Nature Publishing Group. - 0007-0920 .- 1532-1827. ; 110:10, s. 2551-2559
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Tidskriftsartikel (refereegranskat)abstract
- Background: To find improved tools for prognostic evaluation in patients with colorectal cancer (CRC), we have analysed how infiltration of cytotoxic T lymphocytes (CD8(+)) and regulatory T lymphocytes (FoxP3(+)) correlates to prognosis, not only according to quantity and relation, but also to subsite within tumours of different molecular characteristics (microsatellite instability and CpG island methylator phenotype status).Methods: CD8 and FOXP3 expression was evaluated by immunohistochemistry in 426 archival tumour tissue samples from patients surgically resected for CRC. The average infiltration of CD8(+) and FOXP3(+) cells was assessed along the tumour invasive front, in the tumour centre and within the tumour epithelium (intraepithelial).Results: We found that infiltration of CD8(+) T lymphocytes within the tumour epithelium provided the strongest prognostic information (P < 0.001). At the tumour invasive front and tumour centre, FOXP3 expression withheld the strongest association to prognosis (P < 0.001), suggesting FOXP3(+) T-lymphocyte infiltration to be a better prognostic tool than CD8(+) T lymphocytes at these intratumoural subsites. We further analysed the possible prognostic impact of the relation between these T-cell subsets, finding that a high intraepithelial CD8 expression was associated with a better patient outcome, independent of FOXP3 infiltration. In groups of low intraepithelial CD8 expression, however, a high infiltration rate of FOXP3(+) cells at the tumour invasive front, significantly improved prognosis.Conclusions: Analyses of intraepithelial infiltration of CD8(+) T lymphocytes, infiltration of FOXP3(+) T lymphocytes at the tumour front or centre, and the relation between these subsets, may be a valuable tool for predicting prognosis in colon cancer.
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| 47. |
- Ljuslinder, Ingrid, et al.
(författare)
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Increased epidermal growth factor receptor expression at the invasive margin is a negative prognostic factor in colorectal cancer
- 2011
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 128:9, s. 2031-2037
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Tidskriftsartikel (refereegranskat)abstract
- The receptor tyrosine kinase epidermal growth factor receptor (EGFR) is often expressed in solid malignant tumours, and the expression has been correlated to disease progression. Multiple new agents targeted against the EGFR have been developed during the last decade, but treatment selecting criteria are still not clear. This immunohistochemical study includes 386 colorectal cancer patients and focuses on EGFR expression variations within the tumour, comparing central parts to the invasive margin. Positive immunostaining for EGFR was evident in the central part in 176/386 (46%) of analyzed primary tumours. The invasive margin was positive in 222/386 (58%). A similar expression in both the central part and the invasive front was evident in 286/386 (74%). An increased score at the invasive margin compared to central parts (EGFR(i)) was evident in 97/386 (25%) of the tumours. Moreover, the results show a significant survival disadvantage for the EGFR(i) group, both in potentially curatively resected colon cancer patients (n = 170, p = 0.01) and in potentially curatively resected colon and rectal cancer patients combined (n = 273, p = 0.013). Multivariate survival analysis adjusted for age, gender, bowel localisation, grade, stage and tumour type showed an increased risk of cancer death for EGFR(i) tumours (HR, 1.53; 95% CI, 1.04-2.23; p = 0.029). A significant correlation between EGFR expression at the invasive margin and the presence of budding was seen (p = 0.0001). This investigation of a large patient material implies that EGFR immunohistochemical analysis still has a role in risk evaluation of colorectal cancer patients.
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| 48. |
- Lundberg, Ida V, et al.
(författare)
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SOX2 expression is regulated by BRAF and contributes to poor patient prognosis in colorectal cancer
- 2014
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Ingår i: PLOS ONE. - : Public library of science. - 1932-6203. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- Sporadic colorectal cancer (CRC) is a common malignancy and also one of the main causes of cancer deaths worldwide. Aberrant expression of the transcription factor SOX2 has recently been observed in several cancer types, but its role in CRC has not been fully elucidated. Here we studied the expression of SOX2 in 441 CRC patients by immunohistochemistry and related the expression to clinicopathological and molecular variables and patient prognosis. SOX2 was expressed in 11% of the tumors and was significantly associated to BRAF(V600E) mutation, but not to KRAS mutations (codon 12 and 13). SOX2 positivity was correlated to poor patient survival, especially in BRAF(V600E) mutated cases. In vitro studies showed that cells expressing the constitutively active BRAF(V600E) had increased SOX2 expression, a finding not found in cells expressing KRAS(G12V). Furthermore, blocking downstream BRAF signalling using a MEK-inhibitor resulted in a decreased expression of SOX2. Since SOX2 overexpression has been correlated to increased migration and invasion, we investigated the SOX2 expression in human CRC liver metastasis and found that a SOX2 positive primary CRC also had SOX2 expression in corresponding liver metastases. Finally we found that cells overexpressing SOX2 in vitro showed enhanced expression of FGFR1, which has been reported to correlate with liver metastasis in CRC. Our novel findings suggest that SOX2 expression is partly regulated by BRAF signalling, and an increased SOX2 expression may promote CRC metastasis and mediate a poor patient prognosis.
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| 49. |
- Ma, Yi, 1982, et al.
(författare)
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Composite thermoelectric materials with embedded nanoparticles
- 2013
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 48:7, s. 2767-2778
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Tidskriftsartikel (refereegranskat)abstract
- The current status of the development of composite thermoelectric materials with embedded nanoparticles is reviewed. An introduction is given to the suggested mechanisms of improving thermoelectric properties by inclusions of nanoparticles and to experimental methods used to prepare such composites. The progress made in the development of thermoelectric materials with embedded nanoparticles is then covered, grouping the studies according to the optimal temperature range of operation of the materials investigated. Most studies have been devoted to materials within the medium temperature range, followed by low temperature materials, whereas high temperature materials have not yet received much attention within this area. In the majority of the materials systems studied, reports of improved thermoelectric performance upon introduction of nanoparticles in bulk thermoelectrics are found. However, for continued progress in this area, there is a need for systematic experimental studies that unambiguously correlate the resulting physical effects of the nanoinclusions to the measured materials properties.
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| 50. |
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