Terrestrial exposure of a fresh Martian meteorite causes rapid changes in hydrogen isotopes and water concentrations

Determining the hydrogen isotopic compositions and H2O contents of meteorites and their components is important for addressing key cosmochemical questions about the abundance and source(s) of water in planetary bodies. However, deconvolving the effects of terrestrial contamination from the indigenous hydrogen isotopic compositions of these extraterrestrial materials is not trivial, because chondrites and some achondrites show only small deviations from terrestrial values such that even minor contamination can mask the indigenous values. Here we assess the effects of terrestrial weathering and contamination on the hydrogen isotope ratios and H2O contents of meteoritic minerals through monitored terrestrial weathering of Tissint, a recent Martian fall. Our findings reveal the rapidity with which this weathering affects nominally anhydrous phases in extraterrestrial materials, which illustrates the necessity of sampling the interiors of even relatively fresh meteorite falls and underlines the importance of sample return missions

Coastal geomorphological study of St. George bay, Western Naxos, Greece

In order to study the geomorphological and environmental characteristics of St. George bay, in western Naxos, Greece, a series of beachrock samples were examined. Special attention was given to the cement, to obtain information about the formation conditions of the beachrocks. In order to examine the cement of the beachrock samples, the methods of optical microscopy, secondary electron microscopy (SEM) and Raman Spectroscopy were used. The results of the beachrock samples analyses indicate that their formation took place under meteoric and marine vadose zone conditions. Certain characteristics relating to the composition and structure of the cement, sug-gest that the development of the beachrocks took place during sea level rise. © 2021 Gebr. Borntraeger Verlagsbuchhandlung, Stuttgart, Germany

Positive Tc-99m-MIBI scan in a patient with confirmed Paget's disease of bone

A 46-year-old man was referred to our department for a Tc-99m MDP bone scan after he was admitted to our hospital with diffuse bone pain and the subsequent finding of multiple mixed type (lytic-blastic) lesions on routine x-rays. The Tc-99m MDP scan was highly suspicious for malignancy and, therefore, a Tc-99m MIBI scan was performed, which also revealed abnormal uptake in all regions with increased osteoblastic activity. Clinical chemistry and further workup revealed a highly elevated serum alkaline phosphatase and increased excretion of hydroxyproline in the urine. The presumed diagnosis of Paget’s disease of the bone was further confirmed by biopsy

Exhumation of Attica high-pressure rocks in a subduction channel:new metamorphic PT constraints from Attica, NW Cyclades, Greece

The Hymettus area in East Attica contains predominantly greenschist facies schists and marbles; blueschist-facies key minerals are absent in the matrix. However, blueschist facies P-T conditions are recorded in the phyllosilicate mineral chemistry. We provide new integrated thermodynamic data from a lower tectonic unit indicating that the metamorphic path for both prograde and retrograde metamorphism was similar to that in other parts of the Cycladic Blueschist Unit (CBU). New P-T data from the Hymettus area show that a peak pressure of ∼1.4 ± 0.05 GPa was reached at ∼300 ± 25 ºC, followed by exhumation, first with a significant temperature increase to ∼470 ± 20 °C at a pressure of ∼0.8 ± 0.1 GPa, followed by major cooling. The mechanism that exhumed the Hymettus rocks is interpreted to be wedge extrusion in a subduction channel. Accordingly, the 15 km difference in pressure (>0.5 GPa) between the lower and upper tectonic units was eliminated by their juxtaposition during their exhumation in the extruded wedge, which had a shallow-dipping, extensional fault at the top and a parallel thrust at the base. Retrogression of high-to low-pressure assemblages was a result of water infiltration from both sides of the wedge. Both these processes led to a typically symmetrical wedge structure with the relict HP rocks of the LTU in the centre, and the UTU lower pressure rocks in the upper margin

Exhumation of Attica high-pressure rocks in a subduction channel:new metamorphic PT constraints from Attica, NW Cyclades, Greece

The Hymettus area in East Attica contains predominantly greenschist facies schists and marbles; blueschist-facies key minerals are absent in the matrix. However, blueschist facies P-T conditions are recorded in the phyllosilicate mineral chemistry. We provide new integrated thermodynamic data from a lower tectonic unit indicating that the metamorphic path for both prograde and retrograde metamorphism was similar to that in other parts of the Cycladic Blueschist Unit (CBU). New P-T data from the Hymettus area show that a peak pressure of ∼1.4 ± 0.05 GPa was reached at ∼300 ± 25 ºC, followed by exhumation, first with a significant temperature increase to ∼470 ± 20 °C at a pressure of ∼0.8 ± 0.1 GPa, followed by major cooling. The mechanism that exhumed the Hymettus rocks is interpreted to be wedge extrusion in a subduction channel. Accordingly, the 15 km difference in pressure (>0.5 GPa) between the lower and upper tectonic units was eliminated by their juxtaposition during their exhumation in the extruded wedge, which had a shallow-dipping, extensional fault at the top and a parallel thrust at the base. Retrogression of high-to low-pressure assemblages was a result of water infiltration from both sides of the wedge. Both these processes led to a typically symmetrical wedge structure with the relict HP rocks of the LTU in the centre, and the UTU lower pressure rocks in the upper margin

Strontium-89 chloride in the treatment of bone metastases from breast cancer

Sixty-four patients with painful metastatic breast cancer in bone were treated with 2 MBq/kg of strontium-89 chloride as a single intravenous injection. Patients were followed with records of medication, hematology parameters, serial bone and Sr-89 bremsstrahlung images and with a point pain score scale (10-0). The response was assessed during a 6-month period of follow-up. Fifty-two of 64 patients (81%) showed at least a moderate improvement. Eighteen out of the 52 responders showed a dramatic decrease in bone pain (35 %), 21 (40%) presented a satisfactory response and in 13 cases (25%) the response was moderate. Only 12 patients (19%) from the whole group did not feel any improvement on pain palliation. A statistically significant decrease of pretreatment levels of platelets and leukocyte counts was observed after 4-6 weeks of therapy in 50 (70%) patients. Although most patients showed no change in their bone scans after 3 months of treatment, an obvious improvement was observed in 3 of them. Furthermore no additional painful metastases on their bone scintigraphic images were observed. The selective strontium-89 local uptake in metastatic sites was also confirmed directly by bremsstrahlung scans which were absolutely comparable to the respective Tc-99m bone scans. Precautions have been taken against Sr-89 contamination from the patients’ blood or excretions