Geological records of transient fluid drainage into the shallow mantle wedge.

Pore fluid pressure on subduction zone megathrusts is lowered by fluid drainage into the overlying plate, affecting subduction zone seismicity. However, the spatial and temporal scales of fluid flow through suprasubduction zones are poorly understood. We constrain the duration and velocity of fluid flow through a shallow mantle wedge based on the analyses of vein networks consisting of high-temperature serpentine in hydrated ultramafic rocks from the Oman ophiolite. On the basis of a diffusion model and the time-integrated fluid flux, we show that the channelized fluid flow was short-lived (2.1 × 10-1 to 1.1 × 101 years) and had a high fluid velocity (2.7 × 10-3 to 4.9 × 10-2 meters second-1), which is close to the propagation velocities of seismic events in present-day subduction zones. Our results suggest that the drainage of fluid into the overlying plate occurs as episodic pulses, which may influence the recurrence of megathrust earthquakes.

Changes in Serum Trace Element Concentrations Before and After Surgery in Resectable Breast Cancer.

BACKGROUND/AIM: Minerals and trace elements (TEs) play vital roles in normal biological functions and in all cancers. Breast carcinoma is the most commonly occurring cancer in women. The aim of this study was to evaluate changes in TE levels before and after breast cancer surgery and the clinical utility and reliability of TE levels assayed using inductively coupled plasma mass spectrometry (ICP-MS). PATIENTS AND METHODS: Thirteen patients with ductal carcinoma in situ (DCIS) and 34 with invasive ductal carcinoma (IDC) treated with planned surgery were enrolled between August 2017 and February 2019. Blood samples were collected before and the day after resection of the primary tumor. All enrolled patients received mastectomy or quadrantectomy and axillary lymph node dissection/biopsy. Serum TE concentrations were determined using ICP-MS. RESULTS: Changes in boron, titanium, vanadium, chromium, copper, zinc, and selenium levels from before to after surgery differed between IDC and DCIS patients. Boron and copper levels before surgery and changes in titanium, vanadium, and chromium before and after surgery are potential predictors distinguishing DCIS from IDC. Subset analysis showed that chromium is a potential biomarker for luminal subtype, while titanium and chromium are potential biomarkers for pathological staging. CONCLUSION: Changes in serum TEs before and after surgery may help with diagnosis and staging of breast cancer and in establishing TE supplementation protocols.

Equivalent Circuit Models: An Effective Tool to Simulate Electric/Dielectric Properties of Ores-An Example Using Granite.

The equivalent circuit model is widely used in high-voltage (HV) engineering to simulate the behavior of HV applications for insulation/dielectric materials. In this study, equivalent circuit models were prepared in order to represent the electric and dielectric properties of minerals and voids in a granite rock sample. The HV electric-pulse application shows a good possibility of achieving a high energy efficiency with the size reduction and selective liberation of minerals from rocks. The electric and dielectric properties were first measured, and the mineral compositions were also determined by using a micro-X-ray fluorescence spectrometer. Ten patterns of equivalent circuit models were then prepared after considering the mineral distribution in granite. Hard rocks, as well as minerals, are dielectric materials that can be represented as resistors and capacitors in parallel connections. The values of the electric circuit parameters were determined from the known electric and dielectric parameters of the minerals in granite. The average calculated data of the electric properties of granite agreed with the measured data. The conductivity values were 53.5 pS/m (measurement) and 36.2 pS/m (simulation) in this work. Although there were some differences between the measured and calculated data of dielectric loss (tanδ), their trend as a function of frequency agreed. Even though our study specifically dealt with granite, the developed equivalent circuit model can be applied to any other rock.

Transport of toxic metals in the bottom sediments and health risk assessment of Corbicula fluminea (Asiatic clam) collected from Laguna de Bay, Philippines.

Laguna de Bay, the 3rd largest lake in Southeast Asia, is the most significant source of freshwater fish in the Philippines. With decades of unregulated discharge of industrial, domestic, and agricultural wastewaters into the lake, this study investigates the apportionment of heavy metals from the bottom sediments and its impact on the toxicity of Corbicula fluminea (Asiatic clam), a popular food item in the markets. The sediment samples from the western part of the lake contained higher Cd, Cu, Pb, and Zn and lower As and Cr concentrations compared to the eastern part. There were positive correlations for As, Cr, Cu, Pb, and Zn and negative correlations for Cd and Ni concentrations noted between sediments and C. fluminea. Human health risk associated with the consumption of C. fluminea collected from Laguna de Bay was attributed to the following heavy metals: Cu > As > Zn > Cd > Pb > Cr > Ni. Interestingly, the observed trend in toxicities of the shellfish was consistent with the transport phenomenon of heavy metals facilitated by the counterclockwise direction of the bottom current. This study strongly suggests the re-evaluation of the waste management plan in the industrial zones and policies regulating the sale of the shellfish harvest.

Simulation of Electrical and Thermal Properties of Granite under the Application of Electrical Pulses Using Equivalent Circuit Models.

Since energy efficiency in comminution of ores is as small as 1% using a mechanical crushing process, it is highly demanded to improve its efficiency. Using electrical impulses to selectively liberate valuable minerals from ores can be a solution of this problem. In this work, we developed a simulation method using equivalent circuits of granite to better understand the crushing process with high-voltage (HV) electrical pulses. From our simulation works, we calculated the electric field distributions in granite when an electrical pulse was applied. We also calculated other associated electrical phenomena such as produced heat and temperature changes from the simulation results. A decrease in the electric field was observed in the plagioclase with high electrical conductivity and void space. This suggests that the void volume in each mineral is important in calculating the electrical properties. Our equivalent circuit models considering both the electrical conductivity and dielectric constant of a granite can more accurately represent the electrical properties of granite under HV electric pulse application. These results will help us better understand the liberation of minerals from granite by electric pulse application.

The Quaternary Kurobegawa Granite: an example of a deeply dissected resurgent pluton.

The Quaternary Kurobegawa Granite, central Japan, is not only the youngest known granitic pluton exposed on the Earth's surface, it is one of few localities where both Quaternary volcanics and related plutons are well exposed. Here, we present new zircon U-Pb ages together with whole rock and mineral geochemical data, revealing that the Kurobegawa Granite is a resurgent pluton that was emplaced following the caldera-forming eruption of the Jiigatake Volcanics at 1.55 ± 0.09 Ma. Following the eruption, the remnant magma chamber progressively cooled forming the voluminous Kurobegawa pluton in the upper crust (~ 6 km depth) until ~ 0.7 Ma when resurgence caused rapid uplift and erosion in the region. This is the first study to document the detailed spatiotemporal evolution of resurgent pluton for a Quaternary caldera system. Our new findings may contribute significantly to understanding the fate of active caldera systems that can produce supereruptions.

Human health risk associated with heavy metals from consumption of Asiatic Clam, Corbicula fluminea, from Laguna de Bay, Philippines.

Laguna de Bay, the largest and nationally significant freshwater lake ecosystem in the Philippines, has been increasingly subjected to anthropogenic pressures over the years. Domestic, agricultural, and industrial activities in the surrounding areas have contributed directly and indirectly to the deterioration of the lake's overall ecological health and integrity. This study assessed the chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), lead (Pb), and cadmium (Cd) contamination in Asiatic clam, Corbicula fluminea, using quadrupole inductively coupled plasma-mass spectrometry. Estimated daily consumption of Asiatic clam was determined through a social survey. The data from analytical analysis and social surveys were utilized to calculate the target hazard quotient (THQ) to determine the potential health risks of consuming heavy metal-enriched clams to fishing households. Results from the Knowledge, Attitude, and Practices (KAP) survey indicated that the majority of the respondents have an acceptable level of knowledge on the hazards posed by the intake of contaminated clams but disapproved the banning of its collection and consumption. Sampled households with high consumption rates in all municipalities except Victoria were also found to be exposed to imminent health risk due to the high toxicity level of As based on their THQ values. Overall, one-third of the fishing households exposed to elevated health risk based on their total target hazard quotient (TTHQ) values already warrant a concern. The potential human health risks validate the worsening condition of Laguna de Bay. Integrative and holistic management of the lake through collaborative efforts of various stakeholders and institutions is necessary, to restore the health of the ecosystem and safeguard the health of the public.