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Status and Vision for Structural Biology at the Canadian Light Source

100%
Grochulski P., Fodje M., George G.
Acta Physica Polonica A
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2012
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vol. 121
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issue 4
866-870
EN
The status and vision for Structural Biology at the Canadian Light Source (CLS) is presented. The beamlines that have been described in the paper represent a Canadian national resource that is available to science and industry world-wide. They include state-of-the-art infrastructure and include specialized capabilities, many of which are not available elsewhere, including macromolecular crystallography, biological X-ray spectroscopy, soft X-ray spectromicroscopy, as well as small angle and wide angle X-ray scattering beamlines. The vision for Structural Biology at the Canadian Light Source is significantly enhanced by the synergies and collaborations between the users of the different beamlines and by the strengths of the scientific personnel and trainees.
2
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Sulphur XANES Analysis of Cultured Human Prostate Cancer Cells

100%
Kwiatek W., Podgórczyk M., Paluszkiewicz C., Balerna A., Kisiel A.
Acta Physica Polonica A
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2008
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vol. 114
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issue 2
463-470
EN
Prostate cancer is one of the most commonly diagnosed cancers in men throughout the world. It is believed that changes to the structure of protein binding sites, altering its metabolism, may play an important role in carcinogenesis. Sulphur, often present in binding sites, can influence such changes through its chemical speciation. Hence there is a need for precise investigation of coordination environment of sulphur. X-ray absorption near edge structure spectroscopy offers such possibility. Cell culture samples offer histologically well defined areas of good homogeneity, suitable for successful and reliable X-ray absorption near edge structure analysis. This paper presents sulphur speciation data collected from three different human prostate cancer cell lines (PC-3, LNCaP and DU-145). Sulphur X-ray absorption near edge structure analysis was performed on K-edge structure. The spectra of cells were compared with those of cancerous tissue and with organic substances as well as inorganic compounds.
3
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Determination of Changes in Sulphur Oxidation States in Prostate Cancer Cells

100%
Czapla J., Kwiatek W., Lekki J., Steininger R., Göttlicher J.
Acta Physica Polonica A
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2012
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vol. 121
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issue 2
497-501
EN
Prostate cancer cell lines along with selected organic and inorganic compounds used as references were studied with sulphur K-edge X-ray absorption near edge structure spectroscopy. The experiment was performed at the SUL-X beamline of the synchrotron radiation source ANKA, Karlsruhe (Germany). The sulphur was chosen for the studies because it is an essential biological element and out of many relevant factors, it is believed that it can take an important part in cancer transformations. The main goal was to determine which sulphur forms occur in prostate cancer cells and to compare these results with the ones obtained for non-cancerous cells. Therefore oxidation state of this element was analysed with S K-edge X-ray absorption near edge structure spectroscopy. The analysis of K-edge structure was done in order to investigate also the chemical structure of the elements neighbouring the central atom. The preliminary results from sulphur X-ray absorption near edge structure in prostate cancer cell line PC-3 and prostatic epithelial cell line PZ-HPV-7 (which was used as a control) show that there are various oxidation states of sulphur occurring in cells. The set of reference compounds with various sulphur oxidation states was used to establish the relation between the energy of the white line maximum and the oxidation state of sulphur. The equation of linear fit was used to compute the unknown oxidation state. In order to obtain a more detailed information the method of deconvolution of X-ray absorption near edge structure spectra was used. Experimental spectra were fitted with two Gaussian peaks and one arctangent step function. Fitting procedure was performed in Athena code and the deconvolution was used to assign the fraction of each sulphur form. The next step was to compare the results calculated for cancerous and non-cancerous cells. In this work, the first results of these studies are presented.
4
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X-Ray Fluorescence Techniques in Medical Applications: Reference Values of Elements in Human Serum, Urine and Hair

80%
Majewska U., Banaś D., Braziewicz J., Kubala-Kukuś A., Pajek M., Sychowska I., Wudarczyk-Moćko J., Antczak G., Borkowska B., Góźdź S.
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vol. 125
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issue 4
864-868
EN
The aim of undertaken long-term studies of the elemental composition of human serum, urine, and hair is to define reference values of elements concentration. For this purpose the total reflection X-ray fluorescence method was applied to determination of several elements concentration in human serum, urine and hair (S, K, Ca, Fe, Cu, Zn, Br, P, Cr, and Rb in serum samples; Fe, Cu, Zn, Rb, Cr, Mn, and Sr in urine samples; S, K, Ca, Fe, Cu, Br, Zn, Cl, Ti, Cr, Mn, Ni, and Se in hair samples) in the range of concentration from ppb to several hundred ppm. The method of selection of the control group, the experimental setup and its calibration procedure are described. We also present sample preparation methods and procedure of measurements.
5
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Local Structure of Mn in (La_{1-x}Ho_{x})_{2/3}Ca_{1/3}MnO_{3} Studied by X-ray Absorption Fine Structure

80%
Pietnoczka A., Pękała M., Bacewicz R., Drozd V., Fagnard J., Vanderbemden P., Antonowicz J., Zalewski W.
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issue 2
281-285
EN
Results of X-ray absorption fine structure measurements in manganites (La_{1-x}Ho_{x})_{2/3}Ca_{1/3}MnO_{3} with 0.15 < x < 0.50 are presented. When LaMnO_{3} is doped with a divalent element such as Ca^{2+}, substituting for La^{3+}, holes are induced in the filled Mn d orbitals. This leads to a strong ferromagnetic coupling between Mn sites. Ca ions in La_{1-x}Ca_{x}MnO_{3} introduce a distortion of the crystal lattice and mixed valence Mn ions (Mn^{3+} and Mn^{4+}). On the other hand, in manganites (La_{1-x}Ho_{x})_{2/3}Ca_{1/3}MnO_{3} the substitution of La for Ho causes a lattice distortion and induces a disorder, which reduces a magnetic interaction. The ferromagnetic transition temperature and conductivity decrease very quickly with increasing x. The magnetic and transport properties of compounds depend on the local atomic structure around Mn ions. The information on the bond lengths and Debye-Waller factor are obtained from the extended X-ray absorption fine structure (EXAFS) data analysis. The charge state of Mn is determined from the position of the absorption edge in X-ray absorption near edge structure (XANES) data. XAFS results are in good agreement with magnetic characteristics of the studied materials.
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