Chiral logarithms to five loops

We investigate two specific Green functions in the framework of chiral perturbation theory. We show that, using analyticity and unitarity, their leading logarithmic singularities can be evaluated in the chiral limit to any desired order in the chiral expansion, with a modest calculational cost. The claim is illustrated with an evaluation of the leading logarithm for the scalar two-point function to five-loop order.Comment: 13 pages, 5 figure

Development of a Supplement for CHO Cell Culture Serum-free Media by the Fractionation of Peptide mixtures using Nanofiltration

The objective of this work was the investigation of nanofiltration as a potential avenue to fractionate protein hydrolysates and produce protein hydrolysate fractions with stimulating bioactivity for the development of a supplement for a serum-free media. Mammalian cell culture is widely used for the production of therapeutic proteins such as antibodies, interleukins, and vaccines because of the ability of mammalian cells to glycosylate proteins. A complex media with the addition of serum is often required to meet the requirements of the cells. Although serum is a supplement that provides different proteins such as growth factors and hormones, serum has several disadvantages such as high cost, difficulty of downstream processing due to its high protein content and the possibility of microbiological contamination. Protein hydrolysates from plant, animal, or yeast cells contain a complex mixture of peptides and amino acids and have been shown to enhance growth of certain mammalian cell lines cultured in serum-free media. To fractionate peptide mixtures, nanofiltration was investigated in this study. Nanofiltration is a pressure driven membrane separation process based on size and charge. The investigation of pH and NaCl on the filtration performance for two different nanofiltration membranes (HL membrane and G-10 membrane) was achieved using a 24 factorial design. The total peptide concentration, the antioxidant activity, and organic and inorganic content were analyzed in the permeate and retentate fraction. The fractions were also tested for their enhanced growth ability and the specific -interferon productivity with CHO cells. Furthermore the retentate and permeate fractions were analyzed by reversed phase-HPLC to characterize the peptide and free amino acid distribution profile. Through the factorial design, the membrane type was shown to have a significant effect on the filtration performance for both yeast extract and Primatone. A significant difference, but similar for both feed sources, was observed for the total peptide transmission with around 10% for the HL membrane and around 30% for the G-10 membrane. The average permeate flux was significantly lower for the G-10 membrane although the G-10 membrane is a loose nanofiltration membrane with a reported 2500 Da MWCO compared to the HL membrane with a reported 300-500 Da MWCO. The total peptide transmission, organic and inorganic content of the fractions for the two feed sources and membrane type were affected differently according to pH and NaCl addition. These results indicate that the two feed sources are of different composition and that nanofiltration is a possible method to fractionate peptides. The bioactivity of the nanofiltration fractions was tested as a nutrient additive to a serum-free media in CHO cells. It was shown that the productivity is not always related to the cell density, as the highest overall specific interferon productivity was achieved for low cell density similar to the hydrolysate free negative control. Furthermore, the retentate fraction of yeast extract separated with the G-10 membrane at a pH of 8 resulted in the highest cell density. According to these results, nanofiltration is a promising method for the enrichment of protein hydrolysates as a supplement for serum in cell culture

Scope of the direct trimerisation to C3-symmetric cyclotribenzylene derivatives

The scope of the trimerisation reaction of 3-substituted benzyl alcohols was explored. Several C 3 -symmetric cyclotribenzylene derivatives were obtained in preparative useful yields in one step and applied to the short synthesis (one or two steps) of two CTB derivatives, so far only accessible in six or seven linear steps

Die sprachlich konstruierte Wahrnehmung von Sozialhilfebezüger*innen und Arbeitslosen : eine quantitativ informierte qualitative Diskursanalyse

Die vorliegende Arbeit untersucht, wie Sozialhilfebezüger*innen und Arbeitslose in einem Ausschnitt der Schweizer Medien sowie in Leser*innenkommentaren ebenjener Medien dargestellt werden. Zu diesem Zwecke wurde eine quantitativ informierte qualitative Diskursanalyse nach Bubenhofer durchgeführt. Im Zusammenhang mit den Medien wurden hierfür die durch den Swiss-AL-Korpus erhobenen Keywords und Kollokationen zu zusammengehörenden Mustern geclustert. Weiter wurde analysiert, welche Aussagen entsprechend über das vermittelte Bild von Sozialhilfebezüger*innen und Arbeitslosen getroffen werden können. Ausgehend von diesen Aussagen und Fachpublikationen aus dem Bereich der Sozialwissenschaften wurde zudem untersucht, welche Themen im medialen Diskurs nicht vorkommen, inwiefern in diesem Teildiskurs also absences bestehen. In Bezug zu Sozialhilfebezüger*innen konnte Folgendes festgestellt werden: Abgesehen von Lexemen aus dem Bereich der Behörden und Leistungen wird der Diskurs von Vermischungen mit dem Migrationsdiskurs dominiert. Insbesondere in diesem Zusammenhang wurden auch die am Diskurs beteiligten Akteure beleuchtet. Dahingegen werden Gründe für die Notlage und die tatsächliche Lebensrealität der Betroffenen kaum diskutiert. Der Diskurs rund um Arbeitslose wiederum ist stark von statistischen Angaben und den Handlungen der zuständigen Behörden geprägt – die Menschen hinter den Zahlen finden kaum Beachtung. Abschliessend wurde verglichen, inwiefern die Aussagen und absences des medialen Teildiskurs auch in Leser*innenkommentaren beobachtet werden können, die in eigens erstellten Korpora zusammengetragen wurden. Diesbezüglich konnte festgestellt werden, dass grundsätzlich Parallelen zwischen den beiden Teildiskursen bestehen. Es ist aber auch ersichtlich, dass die Leser*innen auch Wissen aus anderen Teildiskursen als aus dem medialen einbeziehen und auch Themen besprechen, die im medialen Teildiskurs keinen Platz finden. This thesis aims to demonstrate how social benefit receivers and the unemployed are depicted within a selection of Swiss newspapers and the comment sections of said media. To achieve this aim, we conducted a quantitatively informed qualitative discourse analysis based on Bubenhofer. Regarding the newspapers, we clustered keywords and collocations gained from the Swiss-AL corpus and analysed the thereby recognized underlying statements about the conveyed image of social benefit receiver and the unemployed. Based on those statements and academic articles issued from scholars of Social Sciences we established the absences prevalent within the discourses lead by the media. With regard to the discourse about social benefit receivers, the following conclusion can be drawn: The migration discourse plays a crucial role, besides lexemes closely linked to the benefits themselves and the authorities involved in the processes to receive them. Especially with regard to the migration discourse, we also investigated the actors involved in the discourse. The media does, however, not discuss the reasons for the financial difficulties and the daily life of those concerned at all. The discourse about the unemployed is highly dominated by statistical information and the action of the relevant authorities, whereas no attention is paid to the individuals behind the figures. Subsequently, we compared these statements and the absences with the comment section corpora we created ourselves. By and large, we were able to discern parallels between the two parts of the discourse. However, it also became clear that readers involve knowledge drawn from other parts of the discourse than the media and discuss topics absent within the discourse lead by the media

JoyaPhos: An Atropisomeric Teraryl Monophosphine Ligand

A topologically well-defined atropisomeric teraryl monophosphine ligand system, prepared by a highly stereoselective arene-forming aldol condensation combined with a direct ester-to-anthracene transformation, is described herein. The ligands were evaluated for gold(I)-catalyzed [2+2] cycloaddition and cycloisomerization reactions as well as a unique intramolecular Pd-catalyzed C-N cross-coupling for the atroposelective synthesis of a N-aryl-indoline bearing a C-N stereogenic axis. The ligand structure induced up to 95:5 stereoselectivity in the asymmetric allylic alkylation reaction and features an interesting dynamic behavior as observed by X-ray crystallographic studies

JoyaPhos: An Atropisomeric Teraryl Monophosphine Ligand

A topologically well-defined atropisomeric teraryl monophosphine ligand system, prepared by a highly stereoselective arene-forming aldol condensation combined with a direct ester-to-anthracene transformation, is described herein. The ligands were evaluated for gold(I)-catalyzed [2+2] cycloaddition and cycloisomerization reactions as well as a unique intramolecular Pd-catalyzed C-N cross-coupling for the atroposelective synthesis of a N-aryl-indoline bearing a C-N stereogenic axis. The ligand structure induced up to 95:5 stereoselectivity in the asymmetric allylic alkylation reaction and features an interesting dynamic behavior as observed by X-ray crystallographic studies

Radiative corrections in K --> 3 pi decays

We investigate radiative corrections to K --> 3 pi decays. In particular, we extend the non-relativistic framework developed recently to include real and virtual photons and show that, in a well-defined power counting scheme, the results reproduce corrections obtained in the relativistic calculation. Real photons are included exactly, beyond the soft-photon approximation, and we compare the result with the latter. The singularities generated by pionium near threshold are investigated, and a region is identified where standard perturbation theory in the fine structure constant alpha may be applied. We expect that the formulae provided allow one to extract S-wave pi pi scattering lengths from the cusp effect in these decays with high precision.Comment: 57 pages, 17 figure

Analysis of discrepancies in Dalitz plot parameters in eta to 3 pion decay

We analyze the Dalitz plot parameters of eta to 3 pion decay in the framework of resummed chiral perturbation theory. This approach allows us to keep the uncertainties in the NNLO and higher orders under better control and estimate their influence. We cannot confirm the suspected discrepancy in the case of the charged decay parameter b, where even small uncertainties in higher orders could accommodate the difference. On the other hand, we find the experimental value of the neutral decay parameter alpha incompatible with an assumption of good convergence properties in the center of the Dalitz plot. We calculate pion-pion rescattering bubble corrections up to three loops and show that these might explain the discrepancy, especially for a low value of the pseudoscalar decay constant in the chiral limit. However, that could indicate a failure of convergence of the chiral series in this channel already at low energies around 500MeV.Comment: Presented at "Hadron Structure 2011", Tatranska Strba, Slovakia, June 2011. 4 pages, 1 figur