Search

The final stages of cervical ripening and parturition resemble an inflammatory process. Although the role of cytokines in both spontaneous and experimentally induced parturitions has been described in several small laboratory animals and humans, the involvement of pro-inflammatory and regulatory cytokines in physiologic parturition in cows has not been determined. In this study, the cytokine expression profiles were assessed in bovine cervical tissue at several stages of pregnancy and at parturition. Serial biopsy samples of the cervix were obtained from 10 cows on day 185 and day 275 of pregnancy (which was on average 5.4 days before parturition) and at parturition. Messenger RNA expression levels of interleukin (IL)-1beta, IL-6, IL-8, IL-10 and tumour necrosis factor (TNF)alpha were determined using real-time polymerase chain reaction and the number of neutrophils and eosinophils was estimated by Luna and Sirius Red staining. At parturition, IL-8 expression had increased 430-fold (p < 0.001) when compared with that of the day 185 of pregnancy, large numbers of neutrophils had invaded the cervix while eosinophils remained scarce, IL-1beta had increased eightfold (p < 0.05) and IL-6 had not changed significantly. Additionally, IL-10 was increased by 10-fold (p < 0.001) and TNFalpha decreased by 57% (p < 0.05) when compared with that of the day 185 of pregnancy. The large increase in expression of IL-8, enabling the influx of neutrophils, is indicative of its important role in the final stage of cervical ripening and at parturition. As previous studies have shown that neutrophils excrete matrix metalloproteinases (MMP), this might contribute to softening of the cervix. In contrast, the only slightly increased levels of IL-1, steady concentrations of IL-6 and decreased TNFalpha, the potential consequences of increased IL-10 expression, indicate that final cervical of cows in ripening at term parturition is an inflammatory process influenced by regulatory cytokines.

Summary: Resume: Zusammenfassung A simulation model for crop-weed competition, parameterized for sugar beet and Chenopodium album L., was validated with experimental data from five field experiments. Between the experiments, 98% of the variation in yield loss, ranging from –6 to 96%, was explained by the simulation model. After validation, the model was used to analyse the backgrounds of the distinct differences in yield loss between the experiments. The contribution of differences in water shortage appeared to be negligible. The number of days between crop and weed emergence, which ranged from 0–31 days, appeared to be the main factor responsible for the differences in yield loss between the experiments (96%). Further analysis showed that water shortage only influences competitive strength of the weeds when overtopped by the crop. Temperature in the period between crop and weed emergence appeared to be an important factor determining the competitive relationships. It is concluded that the period between crop and weed emergence should be expressed as a developmental measure (i.e. degree days) instead of days. Morphological characteristics such as the relative growth rate of leaf area in early growth phases, specific leaf area and height increase largely determined the competitive strength of a species. The effect of physiological characteristics, such as maximum rate of leaf photosynthesis, was less significant. Un modele ecophysiologique pour la competition interspecifique appliquea l'influence de Chenopodium album L. sur la betterave sucriere II. Evaluation du modele Un modele de simulation de la competition culture/adventice, parametre pour la betterave et Chenopodium album L. a ete valide avec des donnees experimentales issues de 5 essais de plein champ. Entre les essais, 98% de la variation de perte de rendement, allant de – 6 a 96%etaient expliques par le modele de simulation. Apres validation, le modele a ete utilise pour analyser les courbes des differences de pertes de rendement entre les essais. Les differences liees au manque d'eau sont negligeables. Le nombre de jour entre la levee de la culture et de l'adventice qui a varie de 0 a 31 jours, est apparu etre le principal facteur responsable des differences entre perte de rendement entre les essais (96%). D'autres analyses ont montre que le manque d'eau influence seulement la vigueur de competition des adventices quand elles sont recouvertes par la culture. La temperature de la periode entre la levee de la culture et de l'adventice apparait etre un important facteur determinant les relations de competition. II estconclu que la periode entre la levee de la culture et de l'adventice devrait etre exprimee en mesure de developpement (par exemple en degres/jour plutot qu'en jour). Des caracteristiques morphologiques comme le taux de croissance relative de la surface foliaire dans les premiers stades, la surface specifique foliaire et l'augmentation de hauteur, determinent grandement la vigueur de competition d'une espece. Les effets des caracteristiques physiologiques comme le taux maximum de la photosynthese foliaires sont moins significatifs. Ein okophysiologisches Modell der interspezifischen Konkurrenz von Chenopodium album auf die Zuckerrube. II. Validierung Ein Simulationsmodell zur Konkurrenz zwischen Kulturpflanze und Unkraut, hier Zuckerrube (Beta vulgaris L.) und Weiser Gansefus (Chenopodium album L.), wurde anhand von Daten aus 5 Freilandversuchen validiert. 98% der Variation der Ertragsverluste, die zwischen –6 und 96% lagen, wurden anhand des Modells erklart. Nach der Validierung wurden mit dem Modell die Bestimmungsgrunde fur die jeweiligen Unterschiede der Ertragsverluste analysiert. Der Beitrag von Unterschieden des Wassermangels erschien als vernachlassigbar. Die Konkurrenzkraft der Unkrauter wurde durch Wassermangel nur beeinflust, wenn sie von der Kulturpflanze uberwachsen wurden. Die Anzahl der Tage zwischen dem Auflaufen der Kulturpflanze und der Unkrautart, das 0 bis 31 Tage auseinander lag, erwies sich als groster Faktor fur die Ertragsverlustunterschiede (96%). Die Temperatur wahrend der Keimperiode war fur die Bestimmung der Konkurrenzbeziehungen wichtig. Deshalb sollte die Keimperiode zwischen Kulturpflanze und Unkraut mit einem Entwicklungsmas (d.h. Temperatursummen) anstatt in Tagen bemessen werden. Morphologische Kenndaten wie relative Wuchsrate der Blattflache in fruhen Entwicklungsstadien, spezifische Blattflache und Wuchshohe bestimmten die Konkurrenzkraft einer Art in hohem Mase. Physiologische Daten wie maximale Photosyntheserate waren weniger signifikant.

This is the second part of a two–part study of the NH3NH4SCN cellulose solvent system. Quasielastic light scattering was used to determine the diffusion coefficients of cellulose in solution and the effective hydrodynamic radius of the dissolved molecules. Additionally, the system was studied using light microscopy to determine the minimum critical volume fraction or liquid crystal formation. Very little change was found in the diffusion coefficients with change in cellulose concentration indicating little interaction between the chains in solution. Values of 7.69 and 2.66 × 108 cm2/s were measured for samples having a degree of polymerization of 153 and 969. The value of the coefficient relating the hydrodynamic volume to the radius of gyration was found to be in the range of 0.33 to 0.53, indicating an extended coil conformation according to the Kirkwood-Riseman theory. The minimum critical volume fractions necessary for liquid crystal formation, υ2′ were 0.039, 0.038, and 0.048 for the three solvent compositions studied. The values calculated for υ2′ based on the measured persistence lengths were much larger than the predicted values, indicating strong deviation from theory or possible aggregation in the system.

Adsorption of Electrolytes on Potato Starch. Heat Development, Swelling and Contraction. On addition of electrolyte solutions to moist potato starch an adsorption takes place, accompanied by the development of heat and by swelling. In alkali salts both phenomena proceed rapidly, usually within a few minutes, and reversible. In potassium salts the evolution of heat depends on the anion (in the sequence of the lyotropic series: rhodanid strongly adsorbed with high thermal effect, sulphate weakly adsorbed with hardly any effect). The amount of swelling on the contrary is hardly different in this case, and the amount of contraction is the same. In this respect there is a contrast with earlier research on the adsorption of water in air-dry starch in which heat development and contraction proved to be proportional. Calcium hydroxyde is adsorbed in much higher quantities than those of the monovalent cations and this adsorption takes a much longer time (up to 50 minutes). The adsorption of hydroxyl ions from monovalent hydroxydes is augmented by the addition of neutral salts. The practical combination NaOH-Na2SO4 is studied.

The complete structure and stereochemical elucidation of flavanone 5,3′,4′-trihydroxy-7β-glucoside has been achieved by the aid of 13C n.m.r.