Freeze fracturing of elastic porous media: a mathematical model.

We present a mathematical model of the fracturing of water-saturated rocks and other porous materials in cold climates. Ice growing inside porous rocks causes large pressures to develop that can significantly damage the rock. We study the growth of ice inside a penny-shaped cavity in a water-saturated porous rock and the consequent fracturing of the medium. Premelting of the ice against the rock, which results in thin films of unfrozen water forming between the ice and the rock, is one of the dominant processes of rock fracturing. We find that the fracture toughness of the rock, the size of pre-existing faults and the undercooling of the environment are the main parameters determining the susceptibility of a medium to fracturing. We also explore the dependence of the growth rates on the permeability and elasticity of the medium. Thin and fast-fracturing cracks are found for many types of rocks. We consider how the growth rate can be limited by the existence of pore ice, which decreases the permeability of a medium, and propose an expression for the effective 'frozen' permeability.

Prevention of anemia in patients with solid tumors receiving platinum-based chemotherapy by recombinant human Erythropoietin (rHuEpo): a prospective, open label, randomized trial by the Hellenic Cooperative Oncology Group.

OBJECTIVES: Platinum compounds are commonly associated with significant anemia. Erythropoietin administration has been found effective in correcting anemia in patients with solid tumors receiving chemotherapy. We conducted a randomized, open label study to assess the efficacy of erythropoietin in preventing transfusions and significant anemia (hemoglobin <10 g/dl) in patients with solid tumors receiving platinum-based chemotherapy. METHODS: One hundred forty-four patients with hemoglobin <13 g/dl were included in this study (72 in each arm). Patients in the treatment arm received 10,000 U of recombinant human erythropoietin (rHuEPO) thrice weekly s.c. during platinum-based chemotherapy, while patients in the control arm received no treatment. RESULTS: All patients were evaluable for efficacy. Transfusions were reduced by the administration of rHuEPO (15.3 vs. 33.3%, p = 0.019), and fewer patients developed significant anemia (16.6 vs. 45.8%, p < 0.0001). Subgroup analysis showed that patients with observed to predicted (O/P) serum erythropoietin levels 0.9 or non-responders. CONCLUSIONS: rHuEPO at a dose of 10,000 U thrice weekly prevents transfusions and development of significant anemia in patients with solid tumors receiving platinum-based chemotherapy.