Experiments on CO2-water-rock interaction at hydrothermal temperatures have been performed to investigate dissolution and precipitation phenomena, including Ca extraction from rocks that might occur during CO2 sequestration into geothermal fields. Distilled water samples were exposed to a CO2 atmosphere at a temperature of 25°C and pressures up to 6 MPa. The resulting solutions were then reacted with granodiorite samples from the Ogachi hot/dry rock field and labradorite, at 200°C and 120°C respectively. The calcium concentrations in the solutions that had reacted with CO2 were twice those with N2 instead of CO2. Combined with the results of thermodynamic calculations, these observations indicate that calcium can be released from rocks (silicates) easily and might be removed as CaCO3 and/or CaSO4 during CO2 sequestration into geothermal fields.
In the development of fiber optic sensors for monitoring scale formation in geothermal brine, high sensitivity and easy handling are desirable features. These characteristics have already been successfully enhanced for U-shaped sensors with other applications. In this work, U-shaped fiber optic sensors for scale formation are reported. The sensors were easily fabricated by bending the exposed core of a multimode fiber optic. Two types of fiber optics, i.e., a polymer cladding silica fiber and a hetero-core structure fiber, were used in preparing the U-shaped sensors. The percentage of total internal reflection between water and the fiber core is affected by the high refractive index of the CaCO3 scale formed on the surface. For laboratory measurements, the optical responses of the U-shaped fiber sensors with respect to calcium carbonate formation were investigated in a mixture of calcium chloride dehydrate and sodium hydrogen carbonate using a white-light source and a spectroscopic detector. The U-shaped fiber sensors were responsive to calcium carbonate formation on the sensor surface. Almost no change in the sensitivity was detected when comparing the U-shaped sensors with their straight counterparts. The transmittance changes were independent of the bending radius. Finally, the U-shaped polymer cladding fiber sensor was used to monitor the silica scale formation in geothermal brine at the Takigami geothermal plant.
860 Background: In patients with unresectable colorectal cancer, primary tumor resection is expected not only local control but also prolongation of survival time. However, in some cases, metastatic tumors have been known to rapidly progress after primary tumor resection. We examined clinical factors associated with acute metastatic progress after primary tumor resection, and it might lead to worse survival. Methods: We retrospectively analyzed 183 patients who were newly diagnosed with unresectable colorectal cancer in our institution between April 2007 and April 2016. Among all patients, 83 patients received resection of primary tumor without the presence of symptoms. They were divided into progression and non-progression group according to metastatic progression that evaluated CT scan from four to six weeks after surgery. We analyzed clinicopathological factors related to acute progression after primary tumor resection using Cox proportional hazards. Results: After resection of the primary tumor, 25 patients were classified into progression group and 58 patients were classified into non-progression group. In progression group, the median percent change in the sum of the longest diameters of target lesions was 29.6% (10.0-191.7%), and 22 (88.0%) patients showed to have new lesions after resection of the primary tumor. Multivariate analysis revealed LDH (HR 4.44, 95%CI 1.15-18.5, p = 0.02), number of liver metastasis (HR 3.28, 95% CI 1.09-10.0, p = 0.03) and RAS status (HR 3.08, 95% CI 1.05-9.46, p = 0.03) were independent baseline factors associated with acute progression after resection of the primary tumor. The median overall survival (OS) was 12.3 and 27.8 months in progression and non-progression group, respectively. Conclusions: Serum LDH, number of liver metastasis, and RAS mutation were baseline factors associated with acute progression of metastatic tumors after resection of primary tumor in patients with unresectable colorectal cancer. These results indicated that the resection of the primary tumor in patients with these factors might be avoided when they have no clinical symptoms.
Chemical and isotopic (D, 18O) compositions of 40 shallow groundwater, 14 observation well water and 2 river water samples in the Sho river fan, Toyama, northern part of central Japan, were analyzed to examine their water quality, origins and water flow in order to obtain baseline geochemical data for application of groundwater to geothermal heat pump (Geo-HP). Water temperatures of the groundwaters in the observation wells are almost constant at 15°C from surface to ca. 60 m in depth and increase up to 25°C at depth of 200 m with the thermal gradient of 6°C/100 m. This geothermal gradient is twice as high as that of the other areas in Japan, suggesting existence of high temperature geothermal sources beneath this region and a high potential for heat usage in winter. The isotopic results show that the groundwaters are a mixture of two big river waters (Sho and Oyabe rivers) and precipitation in the Sho river fan and that the contribution of infiltration from the Sho river has increased in recent 10 years. The Sho river has lower δ18O values than the Oyabe river. The groundwaters shallower than 80 m depth are of a Ca–HCO3 type. Deep groundwaters from observation wells were characterized by high in pH and HCO3 compared to the shallow groundwaters due to ion exchange with rocks containing clay minerals. The deep groundwaters are almost saturated or oversaturated with respect to calcite and dolomite, becoming confined due to the presence of an impermeable layer. In this paper, formation of calcite and iron hydroxide scale inside pipes of the Geo-HP was discussed from the chemical compositions of groundwater to examine whether the water is applicable to geothermal heat pump or not.
Currently, no established marker exists for predicting peritoneal metastasis progression during chemotherapy, although they are major interruptive factors in sequential chemotherapy in patients with advanced gastric cancer (AGC). This multicenter retrospective study was conducted from June 2015 to July 2019, analyzing 73 patients with AGC who underwent taxane-plus-ramucirumab (TAX/RAM) therapy and had their serum carbohydrate antigen 125 (CA125) concentrations measured. Of 31 patients with elevated CA125 levels above a cutoff of 35 U/mL, 25 (80.6%) had peritoneal metastasis. The CA125 concentrations before TAX/RAM treatment were associated with ascites burden. The overall survival was significantly shorter in the CA125-elevated group. CA125 kinetics, measured at a median of 28 days after chemotherapy, were associated with the ascites response (complete or partial response: −1.86%/day; stable disease: 0.28%/day; progressive disease: 2.33%/day). Progression-free survival in the CA125-increased group, defined by an increase of 0.0067%/day using receiver operating characteristic curve analysis, was significantly poorer among patients with peritoneal metastases. In conclusion, this study highlights that CA125 kinetics can serve as an early predictor for the progression of peritoneal metastasis during TAX/RAM treatment.
