Effects of vinyl substitutions on resonance Raman spectra of (bacterio)chlorophylls

Soret resonance and Qy preresonance Raman spectra are reported and compared for a series of (bacterio)chlorophylls. Chlorophyll a, 2-acetylchlorophyll a, bacteriochlorophyll a and 2-vinylbacteriochlorophyll a were studied in the non-protic solvent tetrahydrofuran. These experiments were designed to identify Raman bands corresponding to the stretching mode(s) of the vinyl group at the C-2 position of ring I of chlorophyll a and 2-vinylbacteriochlorophyll a, and to ascertain whether additional bands corresponding to Ca Cm and/or Cb Cb vibrations could be observed in the 1615-1660 cm-1 region. Raman spectra of chlorophyll a and 2-vinylbacteriochlorophyll a exhibit a 1625 cm-1 band, which is absent from the Raman spectra of 2-acetylchlorophyll a and bacteriochlorophyll a. It is assigned to the vC2a C2b mode of the vinyl group. No other band can be definitively assigned to any mode predominantly arising from vinyl motions. The acetyl-containing molecules 2-acetylchlorophyll a and bacteriochlorophyll a give rise to a ca. 1070 cm-1 band, which appears to be related to the presence of the acetyl substituent. The 1615-1660 cm-1 region of the Raman spectra of all four derivatives did not contain any additional band which could be ascribed to modes involving the vCa Cm and/or Cb Cb coordinates

Who Prices Locally? Survey Evidence of Swiss Exporters

Survey information on Swiss exporters is used to test the hypothesis that firm-specific factors, in particular firm size, are important determinants of pricing--to-market (PTM). The survey asked exporters whether they set different prices across markets and, if so, whether price segmentation occurred because of pricing conditions in the local market or other factors. The empirical analysis is based on a probit model that regresses a binary-choice variable of PTM on firm size and other control variables. The main empirical finding is that firm size and PTM are positively and significantly correlated. A further result is that while firms whose main export market is in the Euro area are less likely to engage in PTM, firm size plays a bigger role for them. These results are robust across different PTM classifications, regression specifications, export destinations, and industrial sectors.Pricing to markets, local currency pricing, firm size

Who Prices Locally? Survey Evidence of Swiss Exporters

Survey information on Swiss exporters is used to test the hypothesis that firm-specific factors, in particular firm size, are important determinants of pricing-to-market (PTM). The survey asked exporters whether they set dif- ferent prices across markets and, if so, whether price segmentation occurred because of pricing conditions in the local market or other factors. The empirical analysis is based on a probit model that regresses a binary-choice variable of PTM on firm size and other control variables. The main empirical finding is that firm size and PTM are positively and significantly correlated. A further result is that while firms whose main export market is in the Euro area are less likely to engage in PTM, firm size plays a bigger role for them. These results are robust across different PTM classifications, regression specifications, export destinations, and industrial sectors.Pricing to markets, local currency pricing, .rm size

Biotransformation of caffeoyl quinic acids from green coffee extracts by Lactobacillus johnsonii NCC 533

Acknowledgements The authors are grateful to Nicole Page-Zoerkler and Olivier Mauroux for their technical assistant. We thank David Pridmore and Kimo Makkinen for critical reading of this manuscript.Peer reviewedPublisher PD

Short communication : Mouse skin papilloma formation by chronic dermal application of 7,12-dimethylbenz[a]anthracene is not reduced by diet restriction

No abstract availabl

Mouse skin papilloma formation by chronic dermal application of 7, 12-dimethylbenz[a] anthracene is not reduced by diet restriction

Diet restriction has repeatedly been shown to reduce the incidence of spontaneous and chemically induced tumors in rodents. However, no conclusive data are available to show whether carcinogenesis by chronic exposure to a genotoxic agent can also be retarded. In this study, diet restriction to 70% was investigated for a protective effect on the formation of skin papilloma in male NMRI mice treated twice weekly with 20 nmol 7,12-dimethylbenz(a)anthracene (DMBA). Rather surprisingly, no protection was seen. Both time of onset of papilloma formation (13 weeks in both groups) and time of 50% cumulative incidence (t50; 17.5 and 18 weeks) were similar in the unrestricted and the restricted group. In contrast, a clearly protective elTect was found in mice initiated with 100 nmol DMBA and promoted twice weekly with 2.5 nmol 12-O-tetradecanoylphorbol-13-acetate: the onset of papilloma formation increased from 7 to 11.5 weeks, the t50 was shifted from 8.5 to 19 weeks. Diet restriction, therefore, was not protective under conditions of chronic exposure to a genotoxic carcinogen. It cannot be considered a universal measure of cancer preventio

Personalbewegungen und Fachkräfterekrutierung: Ergebnisse des IAB-Betriebspanels 2005

Zum ersten Mal seit Bestehen des IAB-Betriebspanels liegt hiermit ein gemeinsamer Bericht für West- und Ostdeutschland vor. Damit wird die bisher auf Ostdeutschland fokussierte Berichterstattung auf das gesamte Bundesgebiet ausgedehnt. Der Bericht stellt erste Ergebnisse aus dem IAB-Betriebspanel 2005 zu den folgenden Themen vor: – Entwicklung und Struktur von Betrieben und Beschäftigung – Nutzung von atypischen Beschäftigungsverhältnissen durch die Betriebe – Dynamik auf dem Arbeitsmarkt: Job-Turnover und Labour-Turnover – Personalrekrutierung insbesondere Personalbedarf und Stellenbesetzung bei Fachkräften – Berufsausbildung und Ausbildungsstellen – Betriebliche Weiterbildung Der vorliegende Bericht wurde im Auftrag des IAB gemeinsam von TNS Infratest Sozialforschung (Harald Bielenski, Frauke Bilger und Gabriele Fischer) und SÖSTRA (Vera Dahms, Marek Frei und Jürgen Wahse) verfasst. Ernst Kistler (inifes) hat beratend mitgewirkt. Seitens des IAB haben sich Peter Ellguth, Florian Janik, Susanne Kohaut, Iris Möller und Jens Stegmaier aktiv an der Konzeptdiskussion beteiligt und verschiedene Entwurfsfassungen kritisch kommentiert. Für die zahlreichen konstruktiven Beiträge möchten sich die Autorinnen und Autoren des Berichts ausdrücklich bedanken

Shear thickening, temporal shear oscillations, and degradation of dilute equimolar CTAB/NaSal wormlike solutions

The rheological characterization of dilute and semi-dilute equimolar cetyltrimethylammonium bromide and sodium salicylate solutions is reported, including their linear and nonlinear responses. Start-up experiments and direct birefringence measurements suggest that even at a concentration of as low as 1.0 mM, temporal shear oscillations occur at low shear rates. At concentrations above 10 mM, those low-stress structures vanish and give way to shear-thickening and shear-banding behaviors as seen for other semi-dilute surfactant solutions. Also, the degradation of these solutions after exposure to rubber pump tubing is covere