Drug/Water interactions in hydrogel matrices

The primary aim of this research has been the investigation of the role of water structuring effects in the widely different extents of irritancy displayed by certain antibiotics. The compounds involved were members of the Lincomycin group of antibiotics. The aqueous solution behaviour of these co~pounds was studied using techniques such as vapour pressure osmometry end differential scanning calorimetry (D.S.C.). The effects of the antibiotics on water structure in hydrogel membrane preparations In which the equilibrium water content (E.W.C.) and constituent amounts of freezing and non-freezing water ware varied were also investigated using D.S.C. The permeability of water swollen hydrogel preparations to aqueous antibiotic solutions as well as other solutes were studied. A series of hydrogel preparations into which the antibiotics had been incorporated during polymerisation were developed and used in studies of the effects of the antibiotics end their water structure modifications on the permeation of a range of solutes

Fermeture de phase en astronomie optique

On envisage des simplifications aux techniques récemment proposées afin d'utiliser la « fermeture de phase » en astronomie optique, techniques visant à obtenir la limite théorique de diffraction en imagerie . La méthode envisagée permet de corriger des images isolées, obtenues à courte exposition et dégradées par la turbulence atmosphérique, jusqu'à la limite de diffraction malgré la traversée de l'atmosphère terrestre . Elle prend toute son importance lorsqu'on l'applique à obtenir des images de haute résolution à partir d'une orbite autour de la Terre sans qu'il soit nécessaire de disposer à bord du satellite d'une surface de haute précision optique sur une grande ouverture . A la base de cette méthode : un interféromètre à pupilles multiples, comportant suffisament de redondances internes pour pouvoir séparer les paramètres de l'objet de ceux de l'instrument, chacun étant déterminé alors sans introduire de modèles a priori . Pour une application spatiale, le champ pourrait être dédoublé au moyen de séparateurs et de retards optiques autorisant des mesures à large bande. Une source de référence permet alors dans l'un des champs la stabilisation active de l'instrument - une précision de 1/100 de longueur d'onde paraît accessible, en étudiant une configuration praticable, sur une étoile de magnitude inférieure a 12 . L'autre champ est alors disponible pour de longues intégrations sur des objects faibles .Simplifications of recently proposed techniques for using phase closure to achieve diffraction-limited imaging in optical astronomy are considered . The technique permits synthesis of diffraction-limited images from single, short-exposure, turbulence-degraded images of bright objects viewed through the earth's atmosphere, but is more important as a method for obtaining high resolution images from earth-orbit without the need to put a single large aperture of accurate figure in space . The basis of the method is a multi-aperture interferometer with sufficient redundancy built into the instrument to permit the separation of instrumental and object dependent parameters and thus to permit each of these to be determined without recourse to model building. By use of image-slicing and optical delay lines it is possible to achieve broad-band imaging in two sub-fields . One of the sub-fields may be used as a reference to "shape lock" the instrument to x ./100 accuracy on a source of magnitude < 12, whilst the other is used to obtain long integrations on faint objects

U–Pb zircon ages, geochemical and isotopic compositions of granitoids in Songpan-Garze fold belt, eastern Tibetan Plateau: constraints on petrogenesis and tectonic evolution of the basementevolution of the basement

The Songpan-Garze fold belt, located in the eastern part of the Tibetan Plateau, covers a huge triangular area bounded by the Yangtze (South China), the North China and the Tibetan Plateau blocks. In the northeastern part of the Songpan-Garze fold belt, the Yanggon and Maoergai granitoids provide insights into regional tectono-magmatic events, basement nature and tectonic evolution. U–Pb zircon SHRIMP dating shows that the Yanggon and Maoergai granitoids have magmatic crystallization ages of 221 ± 3.8 Ma and 216 ± 5.7 Ma, respectively. Both the granitoids display adakitic geochemical signatures, suggesting that their magma was derived from partial melting of thickened lower crust. Pb–Sr–Nd isotopic compositions for granitoids reveal that there is an unexposed Proterozoic basement in the Songpan-Garze belt, which has an affinity with the Yangtze block. During development of the Paleo-Tethys ocean, the basement of the Songpan-Garze belt would be a peninsula approaching the Paleo-Tethys ocean from the Yangtze block

Obesity and risk of esophageal adenocarcinoma and barrett\u27s esophagus: A mendelian randomization study

© The Author 2014. Background Data from observational studies suggest that body mass index (BMI) is causally related to esophageal adenocarcinoma (EAC) and its precursor, Barrett\u27s esophagus (BE). However, the relationships may be affected by bias and confounding. Methods We used data from the Barrett\u27s and Esophageal Adenocarcinoma Genetic Susceptibility Study: 999 patients with EAC, 2061 patients with BE, and 2169 population controls. We applied the two-stage control function instrumental variable method of the Mendelian randomization approach to estimate the unbiased, unconfounded effect of BMI on risk of EAC and BE. This was performed using a genetic risk score, derived from 29 genetic variants shown to be associated with BMI, as an instrument for lifetime BMI. A higher score indicates propensity to obesity. All tests were two-sided. Results The genetic risk score was not associated with potential confounders, including gastroesophageal reflux symptoms and smoking. In the instrumental variable analyses (IV), EAC risk increased by 16% (IV-odds ratio [OR] = 1.16, 95% confidence interval [CI] = 1.01 to 1.33) and BE risk increased by 12% (IV-OR = 1.12, 95% CI = 1.00 to 1.25) per 1 kg/m2 increase in BMI. BMI was statistically significantly associated with EAC and BE in conventional epidemiologic analyses. Conclusions People with a high genetic propensity to obesity have higher risks of esophageal metaplasia and neoplasia than people with low genetic propensity. These analyses provide the strongest evidence to date that obesity is independently associated with BE and EAC, and is not due to confounding or bias inherent in conventional epidemiologic analyses