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Wyszukujesz frazę "Jones, K." wg kryterium: Autor


Tytuł:
Properties of New York/New Jersey Harbor Sediments
Autorzy:
Jones, K. W.
Feng, H.
Stern, E. A.
Neuhäusler, U.
Osán, J.
Marinkovic, N.
Song, Z.
Tematy:
89.60.-k
89.20.-a
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/2044657.pdf  Link otwiera się w nowym oknie
Opis:
Sediments found in waterways around the world may contain toxic compounds of anthropogenic origin that can harm the environment and human health. As a result, it is often necessary to remove them and find disposal methods that are environmentally and economically acceptable. Here, we report on results obtained in an experimental program to characterize the nature of the sediment contamination. The objective was to gain a better understanding of the properties of the sediments to develop better methods for understanding the fate and transport of the contaminants and for improving methods for their removal from the sediments. Our investigations made use of X-ray facilities at the Brookhaven National Synchrotron Light Source and the European Synchrotron Radiation Facility at Grenoble, France. The experiments included: measurements of the microstructure of the sediments using computed microtomography, X-ray absorption, and fluorescence microscopy with resolutions as low as 0.2 micrometers to obtain information on the relationships of organic and mineral components of the sediments and on the distribution of contaminants on the surfaces of the sediment grains, investigation of functional groups of chemical compounds using X-ray absorption near-edge spectroscopy and Fourier transform infrared spectroscopy. Scanning electron microscopy and electron probe measurements were made to ascertain the morphology of the sediment surfaces and the distribution of metals on individual sediment grains.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary studies of sediments from the Dobczyce drinking water reservoir
Autorzy:
Skiba, Michał
Reczyński, W.
Jones, K. W.
Jakubowska, M.
Stobiński, M.
Górecki, J.
Posmyk, G.
Olko, M.
Kubica, B.
Gołaś, J.
Dutkiewicz, E. M.
Kwiatek, W. M.
Opis:
The analysis of river and lake sediments indicates that the physical, chemical, biochemical and geochemical processes that influence the fate of toxic compounds and elements in sediments are numerous and complex (for example: sorption - desorption, oxidation - reduction, ion-exchange, biological activity). Due to the above-mentioned general statement, only a long term and complex research programme can lead to satisfactory answers to the questions relating to possible changes of water and environmental quality in the future. The aim of our study consisted in physical and chemical characterisation of sediments in in-depth profiles taken from the Dobczyce reservoir in southern Poland that is a main source of drinking water for the city of Kraków. Due to morphological reasons, 7 layers of sediment samples were distinguished from the ground level to about 90 cm below (total thickness of the sediments in the sampling site). Analysis of grain size distribution and application of x-ray diffraction method, enabled mineralogical description of sediments. The use of proton-induced x-ray emission (PIXE) and atomic absorption spectrometry (AAS) revealed elemental composition of the samples (Al, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn). Concentrations of natural 40K and artificial 137Cs radionuclides were determined by the use of gamma spectrometry. The following facts were established: 1) the oldest (deepest) and newest, recently deposited layers of sediments are similar in their physical and chemical properties. It means that the inflow of contaminants and biogenic compounds to the reservoir has changed little since it was constructed and filled with water; 2) the severe flood in 1997 changed significantly sediment composition and, in fact, led to purification of sediments in the Dobczyce reservoir.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Reduced NGF in gastric endothelial cells is one of the main causes of impaired angiogenesis in aging gastric mucosa
Autorzy:
Brzozowski, Tomasz
Ahluwalia, Amrita
Hoa, Neil
Jones, Michael K.
Zhu, Ercheng
Tarnawski, Andrzej S.
Opis:
This study detected reduced nerve growth factor (NGF) expression within gastric endothelial cells in both elderly patients and aged rats. Reduced NGF correlated with impaired angiogenesis and delayed gastric ulcer healing in aged rats. The defects could be reversed by exogenous NGF via phosphoinositide-3 kinase/serine threonine kinase signaling protein, and mammalian target of rapamycin signaling, and was dependent on serum response factor. These data show that down-regulation of endothelial NGF expression in aging is a significant contributor to impaired gastric mucosal repair.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł

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