Search results for "absorptio"
showing 10 items of 2815 documents
Fruktose – Freund oder Feind?
2016
Die Aufnahme von Fruktose ist in vielen industrialisierten Landern weltweit in den letzten Jahrzehnten stark angestiegen. Dies resultiert u. a. aus einer zunehmenden Verwendung des reinen Monosaccharids oder des sog. „High Fructose Corn Syrup“ (HFCS, Maissirup oder auch Fruktose-Glukose-Sirup) als Susungsmittel. Neben Problemen fur Patienten mit einer angeborenen oder erworbenen Fruktosemalabsorption sowie der seltenen, genetisch bedingten hereditaren Fruktoseintoleranz, wird die vermehrte industrielle Verwendung und die damit einhergehende vermehrte Aufnahme von Fruktose uber die Nahrung als ein Risikofaktor in der Entstehung von Ubergewicht und damit assoziierten metabolischen Erkrankunge…
Dosimetric perturbations of a lead shield for surface and interstitial high-dose-rate brachytherapy.
2014
In surface and interstitial high-dose-rate brachytherapy with either (60)Co, (192)Ir, or (169)Yb sources, some radiosensitive organs near the surface may be exposed to high absorbed doses. This may be reduced by covering the implants with a lead shield on the body surface, which results in dosimetric perturbations. Monte Carlo simulations in Geant4 were performed for the three radionuclides placed at a single dwell position. Four different shield thicknesses (0, 3, 6, and 10 mm) and three different source depths (0, 5, and 10 mm) in water were considered, with the lead shield placed at the phantom surface. Backscatter dose enhancement and transmission data were obtained for the lead shields…
Viršu (Calluna vulgaris) ķīmiskā sastāva izvērtējums dažādās augšanas vietās
2017
Viršu (Calluna vulgaris) ķīmiskā sastāva izvērtējums dažādās augšanas vietās. Pērkone B., zinātniskā vadītāja Mag. chem. lektore Balcerbule Z. Bakalaura darbs, 30 lappuses, 9 attēli, 8 tabulas, 22 literatūras avoti, 5 pielikumi. Latviešu valodā. Darbā noteikts viršu ķīmiskais sastāvs un to augsnes pH vērtības dažādās Latvijas vietās. Paraugi ievākti no meža un purva Smiltenes novada Variņu un Launkalnes pagastu robežteritorijā, un Garkalnes novadā esošā lielceļa A2 (Rīga-Sigulda) ceļmalā. Augu daļām – ziediem, lapām, stumbriem, saknēm – noteikts pelnu saturs. Vara, cinka un mangāna saturs viršu ziedos, stumbros saknēs un arī augsnē noteikts ar liesmas atomabsorbciometru. Dzelzs saturs notei…
ORIGIN: metal creation and evolution from the cosmic dawn
2012
Herder, Jan-Willem den et al.
Photochemical Synthesis of Water-Soluble Gold Nanorods: The Role of Silver Ions in Assisting Anisotropic Growth
2009
The role of Ag+ ions in the ultraviolet-driven photochemical synthesis of Au nanorods (NRs) in aqueous surfactant mixtures has been investigated in order to elucidate the mechanism that drives anisotropic nanoparticle growth. The samples, grown in the presence of varying amounts of Ag+ ions for scheduled irradiation times, have been characterized by ultraviolet−visible−near infrared (UV−vis−NIR) absorption spectroscopy, analytical transmission electron microscopy (ATEM), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and extended X-ray absorption fine structure (EXAFS) measurements. Moreover, the time evolution of size and shape distribution has been investigated by stat…
Lentil Fortified Spaghetti: Technological Properties and Nutritional Characterization
2021
Lentil (Lens culinaris), consumed as a part of the diet worldwide, is a functional dietary ingredient that plays a function in human nutrition as a rich source of bioactive nutrients (low quantities of fat, sodium, and vitamin K
Mathematical modeling of oral absorption and bioavailability of a fluoroquinolone after its precipitation in the gastrointestinal tract
2013
The objective was to characterize the in vivo absorption and bioavailability (BA) of a low solubility, high permeability fluoroquinolone (CNV97101) that precipitates in the gastrointestinal (GI) tract by mathematical modeling approach. In situ rat intestinal perfusion studies were performed to characterize the absorption mechanism. The oral fraction absorbed in vivo was lower than the predicted based on the in situ intestinal permeability. Two additional routes of administration, intraduodenal (ID) and intraperitoneal (IP) were investigated to explore if precipitation in stomach and subsequent partial re-dissolution were the causes of the lower in vivo BA. Ex vivo precipitation studies with…
Speciation of methylmercury in market seafood by thermal degradation, amalgamation and atomic absorption spectroscopy
2014
Sample thermal decomposition followed by mercury amalgamation and atomic absorption has been employed for the determination of methylmercury (MeHg) in fish. The method involves HBr leaching of MeHg, extraction into toluene, and back-extraction into an aqueous l-cysteine solution. Preliminary studies were focused on the extraction efficiency, losses, contaminations, and species interconversion prevention. The limit of detection was 0.018µgg(-1) (dry weight). The intraday precision for three replicate analysis at a concentration of 4.2µgg(-1) (dry weight) was 3.5 percent, similar to the interday precision according to analysis of variance (ANOVA). The accuracy was guaranteed by the use of for…
The effect of the in-medium Θ+ pentaquark on the kaon optical potential
2005
The kaon nuclear optical potential is studied including the effect of the $\Theta^+$ pentaquark. The one-nucleon contribution is obtained using an extension of the J\"ulich meson-exchange potential as bare kaon-nucleon interaction. Significant differences between a fully self-consistent calculation and the usually employed low-density $T\rho$ approach are observed. The influence of the one-nucleon absorption process, $K N \to \Theta^+$, on the kaon optical potential is negligible due to the small width of the pentaquark. In contrast, the two-nucleon mechanism, $K N N \to \Theta^+ N$, estimated from the coupling of the pentaquark to a two-meson cloud, provides the required amount of addition…
Hole burning and pressure phenomena in chromoproteins
1993
Abstract We investigated the behavior of spectral holes under pressure at various frequencies within the inhomogeneous band for two proteins, namely myoglobin and horseradish peroxidase. In order to achieve narrow bandwidth hole burning, the heme chromophore was replaced by protoporphyrin IX and mesoporphyrin IX, respectively. In myoglobin, we found that the pressure induced shift of the holes varied in a strongly non-linear fashion, when the burn-frequency was tuned across the absorption band. In horseradish peroxidase the pressure shift was linear with burn-frequency but changed in a dramatic fashion upon complex formation with a substrate molecule. These observations are interpreted with…