43 research outputs found
The absorption- and luminescence spectra of Mn3+ in beryl and vesuvianite
This research project was supported by the Polish National Science Centre (Grant DEC-2011/03/B/ ST10/06320) and by statutory funding from the Faculty of Earth Sciences at the University of Silesia. Dr. Padhraig S. Kennan (University College Dublin, Ireland) is thanked for help with language.The electron absorption-, photoluminescence- and electron paramagnetic-resonance spectra of Mn3+ in red beryl from Wah Wah Mountains (Utah USA) and of pink- and purple vesuvianite from Jeffrey Mine (Asbestos, Canada) were measured at room- and low temperatures. The crystal field stabilization energies are equal to 130.9 kJ/mol for the red beryl, and 151.5–158.0 and 168.0 kJ/mol for for the pink- and the purple vesuvianite, respectively. The red photoluminescence of Mn3+ was not intensive either at room- or at low temperatures. The high Mn content in the crystals caused the emergence of an additional emission band and short photoluminescence-decay lifetimes. The latter are only 183 μs for beryl and 17 μs for vesuvianite.Narodowe Centrum Nauk
Luminescence properties of tetrahedral coordinated Mn2+ : genthelvite and willemite examples
The cause of the split of4A4E(4G) Mn2+ excited level measured on minerals spectra is discussed. It is our view that ∆E = |4E(4G) - 4A(4G)| should be considered an important spectroscopic parameter. Among the possible reasons for the energy levels splitting taken under consideration, such as the covalent bond theory, the geometric deformation of the coordination polyhedron and the lattice site’s symmetry, the first one was found to be inappropriate. Two studied willemite samples showed that the impurities occur in one of the two available lattice sites differently in both crystals. Moreover, it was revealed that the calculated crystal field Dq parameter can indicate which of the two non-equivalent lattice sites positions in the willemite crystal structure was occupied by Mn2+ . The above conclusions were confirmed by X-ray structure measurements. Significant differences were also noted in the Raman spectra of these willemites
The Mossbauer spectra of prasiolite and amethyst crystals from Poland
Mössbauer spectroscopy of green (prasiolite) and violet (amethyst) quartz crystals from the Sudety Mountains (Poland) has shown that neither Fe2+ nor Fe4+ ions are present in them. Only Fe3+ ions have been identified and only in interstitial positions in channels parallel or perpendicular to the c-axis. The valence of Fe3+ ions did not change as a result of irradiation or annealing. Instead, we believe that the Fe3+ ions move within channels or between them
Spectroscopic and structural investigations of blue afwillite from Ma’ale Adummim locality, Palestinian Autonomy
Until now, only the colourless crystals of mineral afwillite, Ca3(HSiO4)2$2H2O, were known from several
localities around the world. Present work focuses on blue afwillite counterparts from the Ma’ale
Adummim locality in Palestine. Using the wide spectrum of analytical methods we attempted to identify
the causes of this unusual colour. Structural investigation confirms the presence of two tetrahedral
SiO3OH units connected by hydrogen bonds. The Raman spectrum of afwillite, obtained for the first time,
shows the increased number of bands in the range of 785-970 cm-1, whose assignation was correlated
with the presence of two different kinds of structural units: (SiO3OH)3- and its deprotonated counterpart
(SiO4)4-. The heating process at 250 C, in addition to the colour changes from blue to pastel green, shows
the intensity reduction and disappearing of some Raman bands attributed mainly to SiO3OH units. The IR
investigation confirms also the presence of that unit and provides information that the position and
designation of infrared bands above ~2300 cm-1 is related to the strength of hydrogen bonds within the
structure. The stretching and bending OH vibrations of afwillite sample show the partial shift to the
lower spectral frequencies after the H/D isotopic exchange in OH or H2O groups. Based on the results of
the electron absorption and luminescence analyses it has been proposed that the blue colour of afwillite
is caused by hole oxygen defect, most probably SiO3 -
Znaczenie badania zmian hemodynamicznych u pacjentów z przewlekłą chorobą nerek Zastosowanie metod impedancyjnych
W ostatnich latach obserwuje się znaczny wzrostliczby pacjentów dializowanych. Hipotonia śród -dializacyjna jest częstym powikłaniem dializoterapiiistotnie wpływającym na rokowanie pacjentów.W artykule przedstawiono zastosowanie nieinwazyjnejtechniki kardiografii impedancyjnej oraz metodbioimpedancyjnych w monitorowaniu trendówzmian hemodynamicznych w tej grupie chorych.Metody te mogą być użyte do ustalenia bezpiecznejdla pacjenta „suchej masy ciała”. Dokonanorównież przeglądu piśmiennictwa dotyczącegoprzydatności technik impedancyjnych na oddzia -łach dializ.In recent years there has been a significant increasein the number of patients on dialysis. Intradialytichypotension is a common complication of dialysis,significantly affecting the prognosis of patients. Thearticle describes the use of non-invasive techniquesand methods of impedance cardiography to monitortrends in hemodynamic changes in these patients.These methods can be used to determine appropriatemanagement. We also reviewed the literature interms of the usefulness of impedance techniquesin dialysis units
Impact of plant-based diet on lipid risk factors for atherosclerosis
Background: The aim of the study was to investigate the effect of a vegan diet on the serum lipid profile with particular regard to the parameters characterizing the high-density lipoprotein (HDL) fractions in subjects without subclinical atherosclerosis, measured by carotid Doppler ultrasonography.
Methods and Results: Forty-two 23 to 38 year old subjects (21 omnivores and 21 vegans) participated in the study. Compared to the omnivores, the vegan subjects were characterized by lower parameters of lipid profile: total cholesterol (p < 0.001), low-density lipoprotein (LDL)-cholesterol (p < 0.001), non-HDL-cholesterol (p < 0.001), apolipoprotein B (apoB) (p < 0.001) and phospholipids (p < 0.01). Concentration of HDL-cholesterol was apparently similar between groups. Furthermore, the parameters which characterize HDL particles (concentration of apolipoproteins AI [apoAI] and AII, HDL-phospholipids, LpAI fraction and pre-b1-HDL fraction) were not significantly different between omnivore and vegan subjects. The apoB/apoAI ratio in vegans was lower than in omnivores (p < 0.01). There was no difference between serum concentration of triacylglycerols between omnivores and vegans. The activity of paraoxonase-1 and 8-iso-prostaglandin F2a concentration were also not different between the study groups.
Conclusions: We suggest that a vegan diet may have a beneficial effect on serum lipid profile and cardiovascular protection, but it is not associated with changes in HDL composition
Response to the letter regarding the article “Impact of plant-based diet on lipid risk factors for atherosclerosis”
Z dziejów katedr skarbowości i prawa skarbowego oraz katedr prawa finansowego w Polsce
Praca recenzowana / peer-reviewed pape
Components of the Fiber Diet in the Prevention and Treatment of IBD—An Update
Inflammatory bowel disease (IBD) is a group of diseases with a chronic course, characterized by periods of exacerbation and remission. One of the elements that could potentially predispose to IBD is, among others, a low-fiber diet. Dietary fiber has many functions in the human body. One of the most important is its influence on the composition of the intestinal microflora. Intestinal dysbiosis, as well as chronic inflammation that occurs, are hallmarks of IBD. Individual components of dietary fiber, such as β-glucan, pectin, starch, inulin, fructooligosaccharides, or hemicellulose, can significantly affect preventive effects in IBD by modulating the composition of the intestinal microbiota or sealing the intestinal barrier, among other things. The main objective of the review is to provide information on the effects of individual fiber components of the diet on the risk of IBD, including, among other things, altering the composition of the intestinal microbiota