University of Cologne

About: University of Cologne is a education organization based out in Cologne, Germany. It is known for research contribution in the topics: Population & Gene. The organization has 32050 authors who have published 66350 publications receiving 2210092 citations. The organization is also known as: Universität zu Köln & Universitatis Coloniensis.

Genome-wide association analysis of more than 120,000 individuals identifies 15 new susceptibility loci for breast cancer

Abstract: Genome-wide association studies (GWAS) and large-scale replication studies have identified common variants in 79 loci associated with breast cancer, explaining ∼14% of the familial risk of the disease. To identify new susceptibility loci, we performed a meta-analysis of 11 GWAS, comprising 15,748 breast cancer cases and 18,084 controls together with 46,785 cases and 42,892 controls from 41 studies genotyped on a 211,155-marker custom array (iCOGS). Analyses were restricted to women of European ancestry. We generated genotypes for more than 11 million SNPs by imputation using the 1000 Genomes Project reference panel, and we identified 15 new loci associated with breast cancer at P < 5 × 10(-8). Combining association analysis with ChIP-seq chromatin binding data in mammary cell lines and ChIA-PET chromatin interaction data from ENCODE, we identified likely target genes in two regions: SETBP1 at 18q12.3 and RNF115 and PDZK1 at 1q21.1. One association appears to be driven by an amino acid substitution encoded in EXO1.

Controlling Morphology in Polymer–Fullerene Mixtures

Abstract: In the past several years, polymer–fullerene mixtures have been intensely studied for use in organic solar cells because they can be deposited from solution, are compatible with lowcost roll-to-roll fabrication technology, and have shown high power conversion efficiency (g), up to 4–5%. The best devices consist of a single bulk-heterojunction active layer, in which the polymer (donor) and fullerene (acceptor) are deposited from a common solvent. As the solvent dries the donor and acceptor components separate into domains. The final efficiency of the solar cell has been shown to be extremely sensitive to the size, composition, and crystallinity of the formed domains. Improvement of the morphology in devices fabricated with a mixture of [6,6]-phenyl C61-butyric acid methyl ester (PCBM) and regioregular poly(3-hexylthiophene) (P3HT) has been achieved by using heat-treatment techniques and long-time solvent curing, with resulting record efficiencies. More recently, a method for increasing the crystallinity of the P3HT component has been introduced which involves filtering preformed nanofibers of P3HT out of solution and mixing the prepared nanofiber dispersion with PCBM to increase the efficiency of as-cast devices. Interestingly, the best device performance was achieved by mixing lower-molecular-weight (MW) amorphous P3HT back into the solution to reduce the crystalline content of the active layer and, thereby, to increase connection between crystalline domains. Studies of the MW impact on P3HT/PCBM solar cells have indicated that a large polydispersity and number-average molecular weight (Mn) over 19000 g mol -1 leads to improved efficiency. Morphology studies of organic field-effect transistor (OFET) devices indicate that the increased MW leads to better network formation between crystalline domains. The morphology of these improved devices has been studied using transmission electron microscopy (TEM), grazing-angle X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), NMR, and a variety of other optical and electrical techniques. The morphology studies give a picture of a device in which the P3HT forms aligned/crystalline domains, between which are amorphous segments of P3HT and PCBM. These domains form with larger size and crystallinity for higher heat-treatment temperatures and longer solvent soaking times. Depending on the fabrication and measurement techniques, the aligned domains of P3HT are depicted as fibers or as shapeless masses. The majority of these studies do not, however, allow quantification of the percentage of the P3HT that is agglomerated/ crystalline in the final device. Only by making use of the nanofiber filtration technique have the authors been given the ability to control the crystalline content of the P3HT in solution and in the final device. The disadvantages of this technique are the necessity of more complicated preparation, and filtered P3HT is restricted to a fibrous form that requires the addition of amorphous P3HT to provide connections between crystalline domains. We present here a simple method to determine the agglomerated–amorphous ratio of the P3HT and to control the degree of agglomeration/crystallinity of the P3HT in the final device by using a solvent mixing method and no further heat-treatment or prepreparation of the polymer. The most obvious change that heat-treatment and solvent soaking yield on a P3HT:PCBM layers is the change in color. It has been widely reported that the P3HT absorption red-shifts and a series of vibronic peaks become visible at k ∼ 600 nm, 550 nm, and 510 nm. This red-shift has been assigned to increased planarization and stabilization of the P3HT chains that accompanies self-stacking of the polymer. The crystal structure for these self-stacking domains has been solved by using XRD and TEM, and shows a herringbone interconnection of the alkyl chains and an a-dimension stacking distance of 1.6 nm. The p–p chain stacking of the P3HT chains in crystallites has been measured to be 0.38 nm. The herringbone structure and planarization of the P3HT with heating has been confirmed using heteronuclear solid-state NMR measurements. The red-shift in the UV-vis spectrum occurs proportionally to the degree of agglomeration of the P3HT. The pure amorphous electronic spectrum of P3HT or a mixture of P3HT and PCBM is simple to measure. A solution UV-vis spectrum can also be measured in the liquid state. If C O M M U N IC A TI O N

Multiple independent variants at the TERT locus are associated with telomere length and risks of breast and ovarian cancer

Abstract: TERT-locus SNPs and leukocyte telomere measures are reportedly associated with risks of multiple cancers. Using the Illumina custom genotyping array iCOG, we analyzed similar to 480 SNPs at the TERT locus in breast (n = 103,991), ovarian (n = 39,774) and BRCA1 mutation carrier (n = 11,705) cancer cases and controls. Leukocyte telomere measurements were also available for 53,724 participants. Most associations cluster into three independent peaks. The minor allele at the peak 1 SNP rs2736108 associates with longer telomeres (P = 5.8 x 10(-7)), lower risks for estrogen receptor (ER)-negative (P = 1.0 x 10(-8)) and BRCA1 mutation carrier (P = 1.1 x 10(-5)) breast cancers and altered promoter assay signal. The minor allele at the peak 2 SNP rs7705526 associates with longer telomeres (P = 2.3 x 10(-14)), higher risk of low-malignant-potential ovarian cancer (P = 1.3 x 10(-15)) and greater promoter activity. The minor alleles at the peak 3 SNPs rs10069690 and rs2242652 increase ER-negative (P = 1.2 x 10(-12)) and BRCA1 mutation carrier (P = 1.6 x 10-14) breast and invasive ovarian (P = 1.3 x 10(-11)) cancer risks but not via altered telomere length. The cancer risk alleles of rs2242652 and rs10069690, respectively, increase silencing and generate a truncated TERT splice variant.