Cryoprotective Mechanism of DMSO Induced by the Inhibitory Effect on Eutectic NaCl Crystallization.

Cryopreservation is a critical procedure in autologous hematopoietic stem cell transplantation. Dimethyl sulfoxide (DMSO) is the cryoprotectant of choice. Optimization of the cryopreservation protocol in the past revealed a dramatic loss of cell viability associated with a reduction of the DMSO concentration below 2 vol % in the freezing medium. The cryoprotective mechanism of DMSO is usually ascribed to the ability to suppress ice formation and reduce the adverse effects of the freeze-concentrated solution. This work proposes an alternative hypothesis considering the detrimental impact of NaCl eutectic crystallization on cell viability. Thermoanalytical and microstructural analysis of the DMSO effect on eutectic phase transformation of cryoprotective mixtures revealed a correlation between the loss of cell viability and eutectic NaCl crystallization. DMSO inhibits the eutectic crystallization of NaCl and preserves cell viability. Thermodynamic description of the inhibitory action and possible mechanism of cryoinjury are provided.

Study of Potentially Toxic Elements Uptake into Organs of Quercus spp. from Copper Deposits in Slovakia, Italy and Portugal.

The article is focused on the application of Energy dispersive micro X-ray fluorescence spectroscopy as a specific method to determine the contents of potentially toxic elements and its spread in plant tissues. As a model species, Quercus spp. were selected. In order to compare the obtained results with previous research, four well-described abandoned Cu-deposits were selected for sampling: Lubietová (Slovakia), Libiola and Caporciano (Italy), and São Domingos (Portugal). The results of micro X-ray fluorescence spectrometry confirm the irregular contamination of Quercus spp. by potentially toxic elements. The level of contamination is the highest predominantly in the root cortex, where is also the highest Ca contents (with exception of São Domingos). At Lubietová and Caporciano, high Ni content was described in branches cortex, in branches mesoderm also Fe, Cu and Zn. At the same time, the inhibition influence of Ca was also confirmed regarding the input of these elements into plants.

Origin and occurrence of gem-quality, skarn-hosted barite from Jebel Ouichane near Nador in Morocco.

Light-blue barite from Jebel Ouichane in Morocco forms blade-like tabular crystals (up to ca. 10 cm) with superb transparency and lustre and represents one of the most spectacular gem-quality worldwide. The barite is hosted by iron-ore-bearing skarns, developed within Jurassic-Cretaceous limestones, and occurs in close spatial association with calcite. The crystals have their cores enriched in Sr and contain abundant monophase (liquid) fluid inclusions of primary and pseudosecondary origin. The barite probably precipitated slowly at a relatively low supersaturation and under the control of a surface reaction precipitation mechanism. However, there were some episodes during its formation with a fast growth rate and the coupled dissolution and recrystallization processes. A combination of fluid inclusion data and stable δ18O value for barite (+ 6.71‰ VSMOW) suggests that low-salinity barite-forming solutions resulted from the mixing of strongly-diluted meteoric waters (enriched in light oxygen isotope) with magmatic-hydrothermal fluids under low-temperature conditions (< 100 °C). Meanwhile, the mineralizing fluids must have been enriched in Ba, Sr, Ca, Mg, and other elements derived from the alteration of carbonate and silicate minerals in sedimentary and igneous rocks. The coupling between sulphur and oxygen isotope data (+ 16.39‰ VCDT and + 6.71‰ VSMOW, respectively) further suggests that barite crystallized in steam-heated environment, where SO42- derived from magmatic-hydrothermal SO2 reacted with sulphates that originate from the oxidation of H2S under near-surface conditions.

Raman spectroscopic and microthermometric studies of authigenic quartz (the Pepper Mts., Central Poland) as an indicator of fluids circulation.

Differently colored authigenic quartz crystals were found as the druses compound within mudstone heteroliths from the Pepper Mts. Shale Formation (Cambrian unit of the Holy Cross Mts., Central Poland). The genesis of this mineral was established on the basis of fluid inclusion study. Raman microspectroscopy was the key instrumental technique to identify the nature of the compounds trapped in the fluid inclusions. Methane (2917cm-1) or water vapor (broad band ~2500-3000cm-1) occur within two-phased primary inclusion assemblages, while nitrogen (2329cm-1) associated with methane and trace amount of carbon dioxide (1285, 1388cm-1) occur within secondary fluid inclusion assemblage. Temperatures of homogenization of primary fluid inclusions was obtained on the basis of heating experiments and ranged from 171° to 266°C. These values are much higher than expected for the diagenetic system without metamorphic changes what may imply hydrothermal origin of quartz crystals. The source of fluids is uncertain as in the Holy Cross Mts. there was no volcanic activity to the end of Late Devonian. However, fluids originated in metamorphic basin could use deep faults as the migration paths.

Raman spectra of oriented and non-oriented Cu hydroxy-phosphate minerals: libethenite, cornetite, pseudomalachite, reichenbachite and ludjibaite.

Oriented cornetite [Cu3PO4(OH)3], libethenite [Cu2PO4(OH)] and pseudomalachite [Cu5(PO4)2(OH)4] and non-oriented reichenbachite [Cu5(PO4)2(OH)4] and ludjibaite [Cu5(PO4)2(OH)4] minerals from Lubietová and Spania Dolina dump fields, Banská Bystrica, Slovakia were examined by polarized Raman spectroscopy. The examined minerals display the characteristic vibrational modes of PO4 and OH groups and further lattice modes. The PO4 stretching and bending vibrations of the investigated minerals occur between 1150 and 900 cm(-1) and between 700 and 350 cm(-1), respectively. On the other hand, the hydroxyl group stretching and bending modes appear above 3350 cm(-1) and between 900 and 700 cm(-1), respectively. The lattice vibrations occur below 350 cm(-1). The different bond distances of the PO4 groups readily explain the shift of the bands to higher or lower wavenumbers among the studied Cu hydroxy-phosphate minerals.