Reactivity and Dissolution Characteristics of Naturally Altered Basalt in CO2-Rich Brine: Implications for CO2 Mineralization.

Hydrothermally altered basaltic rocks are widely distributed and more accessible than fresh basaltic rocks, making them attractive feedstocks for permanent CO2 storage through mineralization. This study investigates the reactivity and dissolution behaviors of altered basalt during the reaction with CO2-rich fluids and compares it with unaltered basalt through batch hydrothermal experiments using a brine that simulates reservoir conditions with 5 MPa CO2 gas at 100 °C. When using basalt powders to evaluate reactivity, results show that although the leaching rates of elements (Mg, Al, Si, K, and Fe) from altered basalt were generally an order of magnitude lower than those from unaltered basalt in a CO2-saturated acidic environment, similar elemental leaching behavior was observed for the two basalt samples, with Ca and Mg having the highest leaching rates. However, in a more realistic environment simulated by block experiments, different leaching behaviors were observed. When the CO2-rich fluid reacts with altered basalt, rapid and preferential dissolution of smectite occurs, providing a significant amount of Mg to the solution, while Ca dissolution lags. This implies that when altered basalt is utilized for CO2 mineralization, the carbonation step may differ from that of fresh basalt, with predominant Mg carbonation followed by Ca carbonation. This rapid dissolution of Mg suggests that altered basalt is a promising feedstock for CO2 mineralization. This study provides theoretical support for developing technologies to utilize altered basalt for carbon storage.

Clarification of generation mechanism of volatilization flux based on detailed analysis of transport phenomena near the ground surface and quantitative evaluation of influencing factors.

Assessing human health risks associated with inhalation exposure of volatile chemical substances (VCSs) volatilized from contaminated soil requires quantitative evaluation of volatilization fluxes (VFs) and an understanding of how environmental factors impact VF generation. We developed a numerical model that considers advection-dispersion and VCSs volatilization in unsaturated soil, enabling VF prediction through parameter optimization using soil column tests. We conducted parametric analyses to assess how key parameters, such as soil particle size, contamination depth, temperature, and surface soil thickness affect VF generation. By analyzing VCS transport near the ground surface, we uncovered the mechanisms underlying VF generation. We also identified characteristic differences in VF generation behavior linked to soil particle size and gas saturation at the ground surface. Under specific soil particle size conditions, significant VF generation occurred even when contamination was deep underground. This was primarily observed when capillary effect was pronounced, and VCSs continued to be supplied to the ground surface through upward advection. Considering the significant impact of VF generation on human health, our parametric study provides valuable insights into relationships between different parameters and VF behavior, especially under varying ground surface temperatures and surface soil thicknesses. This study contributes to developing effective remediation and risk-reduction strategies. ENVIRONMENTAL IMPLICATION: This research examines the environmental implications of volatile chemical substances (VCSs), including hazardous materials like benzene and trichloroethylene, in contaminated soil. VCSs pose health risks when they volatilize from soil. The study quantifies volatilization fluxes (VF) and elucidates the environmental factors affecting VF generation. These findings are vital for effective environmental management. By comprehending the mechanisms governing VF generation, particularly regarding soil properties like particle size, this research enhances the effectiveness of soil contamination remediation and risk reduction. It emphasizes the essential need for a comprehensive VCS assessment in contaminated soils to protect both human health and the environment.

Multi-layered physical factors govern mercury release from soil: Implications for predicting the environmental fate of mercury.

Despite the recognised risks of human exposure to mercury (Hg), the drivers of gaseous elemental mercury (GEM) emissions from the soil remain understudied. In this study, we aimed to identify the environmental parameters that affect the GEM flux from soil and derive the correlations between environmental parameters and GEM flux. Principal component analysis (PCA), factor analysis (FA), and structural equation modelling (SEM) were performed on samples from forest and non-forest sites. The associated results revealed the impact of each environmental parameter on GEM flux, either due to the interaction between the parameters or as a coherent set of parameters. An introductory correlation matrix examining the relationship between two components showed a negative correlation between GEM flux and atmospheric pressure at the two sites, as well as strong correlations between atmospheric pressure and soil temperature. In cases of non-forest open sites with no trees, the PCA and FA results were consistent, indicating that atmospheric pressure, solar irradiance, and soil moisture-defined as primary causality-are largely independent drivers of GEM flux. In contrast, the PCA and FA results for the forest areas with high humidity, tree coverage, and shade were inconsistent, confirming the hypothesis that primary causality affects GEM flux rather than consequent parameters driven by primary causality, such as air and soil temperature and atmospheric humidity. The SEM results provided further evidence for primary and consequent causality as crucial drivers of the GEM flux. This study demonstrates the importance of key primary parameters, such as atmospheric pressure, solar irradiance, and soil moisture content, that can be used to predict mercury release from soils, as well as the importance of consequent parameters, such as air and soil temperature and atmospheric humidity. Monitoring the magnitude of these environmental parameters alone may facilitate the estimation of mercury release from soils and be useful for detailed modelling of soil-air Hg exchange.

Relationship between the Selvester QRS Score and Coronary Microvascular Dysfunction Assessed by the Index of Microcirculatory Resistance.

Objective The index of microvascular resistance (IMR) is an invasive method for quantifying the coronary microvasculature independent of the presence and degree of epicardial stenosis during cardiac catheterization, whereas the Selvester QRS score, which is related to myocardial damage, is a relatively simple and non-invasive measurement procedure. We investigated the relationship between the QRS score and coronary microvascular dysfunction (CMD) assessed via IMR. Methods Data from 74 patients who underwent invasive coronary physiological measurements were retrospectively reviewed. Using a coronary wire, we measured IMR by the hyperemic mean transit time and distal coronary pressure. We also determined a simplified QRS score following the Selvester QRS score criteria by 12-lead electrocardiography. After determining the best cutoff value for the QRS score to predict IMR ≥25, which was defined as CMD by the Coronary Vasomotion Disorders International Study Group, patients were categorized into the QRS score ≥3 (n=16) and the QRS score 0-2 (n=58) groups. Results IMR in the QRS score ≥3 group was significantly higher in comparison to the QRS score 0-2 group (31; IQR: 19-57 vs. 20; IQR: 14-29, p<0.01). The percentage of patients with IMR ≥25 in the QRS score ≥3 group was significantly higher than that in the QRS score 0-2 group (69% vs. 34%, p=0.01). Conclusion A higher QRS score was associated with CMD, as estimated by IMR. The Selvester QRS score is noninvasive parameter that is potentially useful for predicting CMD.

Left-atrial volume reduction reflects improvement of cardiac sympathetic nervous function in patients with severe aortic stenosis after transcatheter aortic valve replacement.

Trans-catheter aortic valve replacement (TAVR) is an excellent alternative intervention for surgical aortic valve replacement. Cardiac sympathetic nervous (CSN) function and left atrial (LA) volume are both important prognostic factors in patients with aortic stenosis (AS) after TAVR. The relationship between the two clinical factors is unknown, however. This retrospective observational study aimed to assess the correlation between CSN function and LA volume in 48 symptomatic patients with severe AS (median age: 85 years, IQR 82-88 years; 81% female) before and after TAVR. CSN function was assessed by performing 123I-metaiodobenzylguanidine (MIBG) scintigraphy before and 6 months after TAVR, and the delayed heart-to-mediastinum ratio (dHMR) and washout rate (WR) were calculated. We also performed transthoracic echocardiography near the same time. TAVR improved the dHMR, WR, and LA volume index (LAVI) (dHMR: median 2.89 [IQR 2.62-3.23] vs. 2.98 [2.49-3.25], p = 0.0182; WR: 28% [24-38] vs. 23% [16-32], p < 0.0001; LAVI: 47.7 mL/m2 [37.8-56.3] vs. 41.2 mL/m2 [33.7-56.1], p = 0.0024). In multiple linear regression analysis, the percentage change in LAVI from baseline to post-TAVR (∆LAVI%) was an independent predictor of change in dHMR from baseline to post-TAVR (ß = - 0.35, p = 0.0110). In conclusion, LA volume reduction reflected CSN functional improvement after TAVR. In patients with TAVR, ∆LAVI% might be a valuable parameter for evaluating CSN functional recovery.

Relationship Between Attenuated Plaque Identified by Intravascular Ultrasound and Thrombus Formation After Excimer Laser Coronary Angioplasty.

BACKGROUND: Excimer laser coronary angioplasty (ELCA) has been reported to be a safe and effective atherectomy device in percutaneous coronary intervention (PCI). However, thrombotic complications after ELCA have been occasionally observed. In this study, we evaluated the impact of attenuated plaque on thrombus formation and transient no-reflow after ELCA. METHODS: This study enrolled 58 lesions in 56 patients who underwent PCI with ELCA. It was a retrospective observational study at a single center. All lesions were imaged by intravascular ultrasound (IVUS) before and immediately after ELCA. On the plaque with ultrasound attenuation, attenuation angle per millimeter and attenuation length were measured. ELCA-induced thrombus was detected by IVUS, and transient no-reflow after ELCA was recorded. RESULTS: Thrombus was detected in 14 lesions (30 %), and transient no-reflow occurred in 3 lesions (5 %). Lesions with thrombus had a higher mean attenuation angle (median [interquartile range] 142° [112°-152°] vs. 64° [0°-115°]; p = 0.001), maximum attenuation angle (209° [174°-262°] vs. 86° [0°-173°]; p < 0.001), and longer attenuation length (12 mm [8 mm-17 mm] vs. 2 mm [0 mm-5 mm]; p < 0.001). Lesions with thrombus leading to transient no-reflow had a longer lipid length and a significantly higher troponin I level after PCI. CONCLUSIONS: IVUS-identified attenuated plaque was strongly correlated with ELCA-induced thrombus. Furthermore, attenuation length may predict transient no-reflow.

Influence of non-uniform flow on toxic elements transport in soil column percolation test.

The influence of flow channels on the leaching behavior of toxic elements in contaminated soil cannot be neglected in a column percolation test. This study presents a visualization of the flow channel formed in the soil and evaluated the relationship between the leaching behavior of soil components and flow. We conducted column percolation tests with two types of filling methods (Compaction and No compaction) and used X-ray computed tomography to visualize the soil structure and non-uniform flow. Additionally, the variations of flow in a cross section of water were evaluated using hydraulic conductivity based on differential pressure. Under No compaction, a flow occurred throughout the soil column at the beginning of the water passage, but a non-uniform flow emerged as the liquid-solid ratio increased; under Compaction, a non-uniform flow was formed from the beginning of water passage. The leaching behavior of the major components and toxic elements from soil with high adsorptive properties was significantly affected by the filling method up to a liquid-solid ratio of 2. These results suggest that the non-uniform flow formed in the column percolation test has a significant impact on the leaching of soil components.

Potentially toxic elements pose significant and long-term human health risks in river basin districts with abandoned gold mines.

Gold (Au) mining area is known to be one of the major sources of toxic elements; however, the potential risks of toxic elements from abandoned Au mines to the surrounding river basin districts and human exposure pathways to toxic elements need to be clarified. In this study, the distribution and mobilities of nine toxic elements (As, Cd, Cu, Pb, Sb, Zn, Cr, Ni and V) in Kesennuma City, Tohoku Region in Japan, a typical Au-mining district with several river basins, were studied through a geochemical survey (including element total concentrations and water-/acid-leaching concentrations determinations, as well as GB calculations), and environmental assessment on these elements in soil, river sediment, and river water samples from the study area. The contamination evaluation by index of geo-accumulation (Igeo) and enrichment factor (EF) suggested that As, Cu, Ni and Sb enrichments were greatly observed in the vicinity of the abandoned Au mines; moreover, calculated GB upper values for Cu in the river sediment surpass that of Tohoku Region. It has been found in this study that each element has particular mobility, which eventually influences its exposure pathway to humans. For instance, As in soil and sediment poses adverse non-carcinogenic risks and unacceptable carcinogenic risks to especially children mainly through groundwater ingestion. To minimize the potential risks associated with exposure to toxic elements in Au-mining districts, effective risk management measures should be implemented around river system by Au-mining companies even after their long-time closures, based on the consideration of each element's mobility.

Role of water in unexpectedly large changes in emission flux of volatile organic compounds in soils under dynamic temperature conditions.

Understanding the diffusive transport behavior of volatile organic compounds (VOCs) in near-surface soils is important because soil VOC emissions affect atmospheric conditions and climate. Previous studies have suggested that temperature changes affect the transport behavior; however, the effect of these changes are poorly understood. Indeed, under dynamic temperature conditions, the change in VOC flux is much larger than that expected from the temperature dependency of the diffusion coefficient of VOCs in air. However, the mechanism is not well understood, although water in soil has been considered to play an important role. Here, we present the results of experiments for the upward vertical vapor-phase diffusive transport of two VOCs (benzene and tetrachloroethylene) in sandy soil under sinusoidal temperature variations of 20-30 °C, as well as its numerical representation. The results clarify that the unexpectedly large changes in emission flux can occur as a result of changes in the VOC concentration gradient due to VOC release (volatilization) from/trapping (dissolution) into water, and that such flux changes may occur in various environments. This study suggests the importance of a global evaluation of soil VOC emissions by continuous measurements in various soil environments and/or predictions through numerical simulations with thorough consideration of the role of water in dynamic soil environments.

P-Wave Terminal Force V1 Is Associated with Left Ventricular Diastolic Function in Patients with No Significant Perfusion Abnormality.

P-wave terminal force in lead V1 (PTFV1) is a marker of increased left atrial (LA) overload. Whether PTFV1 is associated with left ventricular (LV) diastolic function remains undetermined. We tested the hypothesis that PTFV1 is associated with LV diastolic parameters derived from gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with no significant perfusion abnormalities.The study population included 158 patients with preserved ejection fraction and no significant perfusion abnormalities. The amplitude and duration of the P-wave negative phase in lead V1 were measured using an electrocardiogram, and PTFV1 was calculated. The peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters using gated SPECT.PTFV1 showed a weak correlation with the LA volume index (r = 0.31; P < 0.001). Significant associations were observed between PTFV1 and PFR (r = -0.27; P < 0.001) and 1/3 MFR (r = -0.26; P = 0.001). A multivariate linear regression analysis showed that age (ß = -0.26; P < 0.001), LV end-diastolic volume index (ß = -0.27; P = 0.001), and PTFV1 (ß = -0.15; P = 0.036) were significant factors associated with PFR. Moreover, male gender (ß = -0.16; P = 0.041), LV mass index (ß = -0.17; P = 0.046), and PTFV1 (ß = -0.17; P = 0.022) were significant factors associated with the 1/3 MFR.PTFV1 is associated with LV diastolic function, as derived from gated SPECT in patients with no significant perfusion abnormalities.

Current conditions and significance of outpatient cardiac rehabilitation and home nursing-care services in heart failure patients with mid-range or preserved ejection fraction: post-hoc analysis of the REAL-HF registry.

The effects of outpatient cardiac rehabilitation (OCR) implementation and home nursing-care services (HNS) use are not well defined in patients with heart failure (HF) with mid-range or preserved left-ventricular ejection fraction (EF) (HFmrEF or HFpEF). Through a post-hoc analysis of the HF registry in Hiroshima Prefecture of Japan (REAL-HF), we investigated the current conditions and significance of OCR and HNS in HFmrEF or HFpEF patients. The REAL-HF enrolled adult patients hospitalized with HF in eight regional core hospitals. Patients discharged home were followed for conditions of OCR and HNS and the primary endpoints (all-cause death or unscheduled readmission) for 1 year. The patients were classified into HF with reduced EF (< 40%) (HFrEF) or HFmrEF (40% ≤ EF < 50%) or HFpEF (EF ≥ 50%) group. We followed 195 HFrEF and 381 HFmrEF or HFpEF patients. OCR was generally underutilized, especially in HFmrEF or HFpEF patients (rate of completion [5-month program], 3.2%), whereas HFmrEF or HFpEF patients were more likely to use HNS after discharge home than HFrEF patients (44.1% vs. 27.2%, P < 0.0001). Patients with the use of HNS generally had lower scores of Mini-Mental State Examination and EuroQol 5 dimensions than those without. Multivariate analysis adjusted for medical and social factors showed that the completion of OCR was a strong negative predictor of the primary endpoints both in HFrEF (hazard ratio [HR] 0.10; 95% confidence interval [CI] 0.01-0.75; P = 0.025) and HFmrEF or HFpEF (HR 0.11; 95% CI 0.01-0.78; P = 0.028) patients, whereas the use of HNS was a positive predictor only in HFmrEF or HFpEF patients (HR 1.41; 95% CI 1.00-1.97; P = 0.047). In conclusion, continuous OCR, despite its inadequate implementation, was associated with favorable overall outcomes, while the necessity for HNS related to impaired cognitive function and quality of life was associated with poorer overall outcomes in HFmrEF or HFpEF patients discharged home. Further study is warranted to fully consider the factors related to OCR implementation and HNS use.

Factors Influencing Cardiac Sympathetic Nervous Function in Patients With Severe Aortic Stenosis: Assessment by 123I-Metaiodobenzylguanidine Myocardial Scintigraphy.

BACKGROUND: Numerous studies have shown that 123I-metaiodobenzylguanidine (MIBG) scintigraphy, an index of cardiac sympathetic nervous (CSN) activity, is useful for predicting prognosis in patients with heart failure. However, the factors influencing the CSN activity of patients with severe aortic stenosis (AS) remain unclear. METHODS: We enrolled 91 patients with severe AS who underwent 123I-MIBG scintigraphy, coronary computed tomography (CCT), and transthoracic echocardiography. When CCT angiography (CCTA) showed an obstructive epicardial artery, invasive coronary angiography was performed within 1 week of CCTA. RESULTS: There were 21 male and 70 female patients with a mean age of 84±5 years. Eighty-five (85) patients (93%) had hypertension and 13 patients (14%) had diabetes. Two (2) patients (2%) had previous myocardial infarction and eight (9%) had a previous coronary intervention. All patients had severe AS: aortic valve area was 0.63±0.18 cm2 and the mean pressure gradient was 56±19 mmHg. Regarding 123I-MIBG parameters, early heart-to-mediastinum (H/M) ratio was 3.1±0.5, delayed H/M ratio was 2.8±0.6, and the washout rate (WR) was 35%±13%. Multivariable linear regression analysis showed that coronary artery disease (ß=-0.30, p=0.002) was an independent predictor of delayed H/M ratio, and that aortic valve area (ß=-0.20, p=0.048) was an independent predictor of WR. CONCLUSIONS: Our findings suggest that coronary artery disease is an independent predictor of delayed H/M ratio, and aortic valve area is an independent predictor of WR in patients with severe AS.

A laboratory study of hydraulic fracturing at the brittle-ductile transition.

Developing high-enthalpy geothermal systems requires a sufficiently permeable formation to extract energy through fluid circulation. Injection experiments above water's critical point have shown that fluid flow can generate a network of highly conductive tensile cracks. However, what remains unclear is the role played by fluid and solid rheology on the formation of a dense crack network. The decrease of fluid viscosity with temperature and the thermally activated visco-plasticity in rock are expected to change the deformation mechanisms and could prevent the formation of fractures. To isolate the solid rheological effects from the fluid ones and the associated poromechanics, we devise a hydro-fracture experimental program in a non-porous material, polymethyl methacrylate (PMMA). In the brittle regime, we observe rotating cracks and complex fracture patterns if a non-uniform stress distribution is introduced in the samples. We observe an increase of ductility with temperature, hampering the propagation of hydraulic fractures close to the glass transition temperature of PMMA, which acts as a limit for brittle fracture propagation. Above the glass transition temperature, acoustic emission energy drops of several orders of magnitude. Our findings provide a helpful guidance for future studies of hydro-fracturing of supercritical geothermal systems.

Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks.

Improving geothermal systems through hydraulic stimulation to create highly permeable fractured rocks can induce seismicity. Therefore, the technique must be applied at a moderate intensity; this has led to concerns of insufficient permeability enhancement. Adding chemical stimulation can mitigate these issues, but traditional methods using strong mineral acids have challenges in terms of achieving mineral dissolution over long distances and highly variable fluid chemistry. Here, we demonstrate a novel chemical stimulation method for improving the permeability of rock fractures using a chelating agent that substantially enhances the dissolution rate of specific minerals to create voids that are sustained under crustal stress without the challenges associated with the traditional methods. Applying this agent to fractured granite samples under confining stress at 200 °C in conjunction with 20 wt% aqueous solutions of sodium salts of environmentally friendly chelating agents (N-(2-hydroxyethyl)ethylenediamine-N, N', N'-triacetic acid and N, N-bis(carboxymethyl)-L-glutamic acid) at pH 4 was assessed. A significant permeability enhancement of up to approximately sixfold was observed within 2 h, primarily due to the formation of voids based on the selective dissolution of biotite. These results demonstrate a new approach for chemical stimulation.

Dynamic evaluation method for planning sustainable landfills using GIS and multi-criteria in areas of urban sprawl with land-use conflicts.

Landfill site selection is problematic in many countries, especially developing nations where there is rapid population growth, which leads to high levels of inadequate waste disposal. To find sustainable landfill sites in sprawling cities, this study presents an approach that combines geographic information system (GIS) with multi-criteria (social, environmental and, technical criteria) and the population growth projection. The greater Maputo area in Mozambique was selected as a representative city for the study, which is undergoing rapid urbanization. Six criteria, i.e., land use, transport networks, hydrology, conservation reserve, geology and slope, were considered and overlaid in the GIS using an analytic hierarchy process (AHP). The arithmetic projection of the population trend suggests that the greater Maputo area is experiencing a rapid and uncontrolled population growth, especially in Matola city. These pronounced changes in population then significantly change the landfill placement decision making. Dynamic and static scenarios were created, based on the analysis of multi-criteria and the areas likely to undergo future increased population growth. A comparative evaluation in a scenario of dynamic behavior considering future population showed that suitable areas for landfill sites have been drastically modified due to social and environmental factors affected by population distribution in some regions. The results indicate that some suitable areas can generate land use conflicts due to population growth with unplanned land use expansion. Finally, the western part of Matola city is recognized as the most recommendable landfill site, which can serve both Maputo and Matola city with affordable costs. This study provides an effective landfill placement decision making approach, which is possible to be applied anywhere, especially in developing countries to improve sustainable municipal solid waste management systems.

The Monocyte to High-Density Lipoprotein Cholesterol Ratio Is Associated with Left Ventricular Diastolic Function in Patients with No Significant Perfusion Abnormality.

The monocyte to high-density lipoprotein cholesterol (HDL-C) ratio has been considered to be a prognostic marker. Whether this ratio is associated with left ventricular (LV) diastolic function remains undetermined. We tested the hypothesis that the monocyte to HDL-C ratio is associated with LV diastolic parameters derived from gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with no significant perfusion abnormality.The study population included 196 patients with no significant perfusion abnormalities and preserved ejection fraction. The peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters using gated SPECT. Monocyte counts and plasma HDL-C levels were also examined.Significant associations were observed between the monocyte to HDL-C ratio and PFR (r = -0.20; P = 0.005) and 1/3 MFR (r = -0.19; P = 0.009). Multivariate linear regression analysis was performed to determine factors associated with LV diastolic parameters. Age (ß = -0.27; P < 0.001), LV end-diastolic volume (ß = -0.19; P = 0.034), and monocyte to HDL-C ratio (ß = -0.15; P = 0.027) were determined to be significantly associated with PFR. Moreover, age (ß = -0.13; P = 0.007), LV mass index (ß = -0.18; P = 0.037), and the monocyte to HDL-C ratio (ß = -0.13; P = 0.045) were significantly associated with 1/3 MFR.These results demonstrated that the monocyte to HDL-C ratio is associated with LV diastolic function, as derived from gated SPECT in patients with no significant perfusion abnormality.

Enhancement of aragonite mineralization with a chelating agent for CO2 storage and utilization at low to moderate temperatures.

Among the CaCO3 polymorphs, aragonite demonstrates a better performance as a filler material in the paper and plastic industries. Despite being ideal from the environmental protection perspective, the production of aragonite particles via CO2 mineralization of rocks is hindered by the difficulty in achieving high production efficiencies and purities, which, however, can be mitigated by exploiting the potential ability of chelating agents on metal ions extraction and carbonation controlling. Herein, chelating agent N,N-dicarboxymethyl glutamic acid (GLDA) was used to enhance the extraction of Ca from calcium silicate and facilitate the production of aragonite particles during the subsequent Ca carbonation. CO2 mineralization was promoted in the presence of 0.01-0.1 M GLDA at ≤ 80 °C, with the maximal CaCO3 production efficiency reached 308 g/kg of calcium silicate in 60 min using 0.03 M GLDA, which is 15.5 times higher than that without GLDA. In addition, GLDA showed excellent effects on promoting aragonite precipitation, e.g., the content of aragonite was only 5.1% in the absence of GLDA at 50 °C, whereas highly pure (> 90%, increased by a factor of 18) and morphologically uniform aragonite was obtained using ≥ 0.05 M GLDA under identical conditions. Aragonite particle morphologies could also be controlled by varying the GLDA concentration and carbonation temperature. This study proposed a carbon-negative aragonite production method, demonstrated the possibility of enhanced and controlled aragonite particle production during the CO2 mineralization of calcium silicates in the presence of chelating agents.

Associations of frontal QRS-T angle with left ventricular volume and function derived from ECG-gated SPECT in patients with advanced chronic kidney disease.

BACKGROUND: The frontal QRS-T angle is one of markers of ventricular repolarization. We investigated whether or not the frontal QRS-T angle could predict left ventricular (LV) volume and function derived from ECG-gated SPECT in patients with advanced chronic kidney disease (CKD). METHODS: Two hundred and twelve patients with advanced CKD defined as estimated glomerular filtration rate of < 45 ml min-1/1.73 m2 were enrolled. Wide QRS-T angle was defined as its angle of > 90°, and was considered abnormal. Enlarged LV end-diastolic volume (LVEDV) was defined as LVEDV index of > 76 ml m-2 in men and > 57 ml m-2 in women. Reduced LV ejection fraction (LVEF) was defined as LVEF of < 40%. RESULTS: Fifty-one patients (24%) had wide QRS-T angle, and 161 patients (76%) had normal QRS-T angle. Patients with wide QRS-T angle had larger SSS [9 (5-16) vs 4 (1-9), p < 0.001], larger LVEDV index (69 ± 29 vs 50 ± 18 ml m-2, p < 0.001) and lower LVEF (47 ± 13 vs 59 ± 12%, p < 0.001) than those with normal QRS-T angle. Multivariate analysis showed that wide QRS-T angle (odds ratio 5.93; 95% CI 2.55-14.33; p < 0.001) was significantly associated with enlarged LVEDV, whereas SSS severity was not. Severely abnormal SSS (odds ratio 3.80; 95% CI 1.16-14.05; p < 0.03) and wide QRS-T angle (odds ratio 5.67; 95% CI 2.10-16.22; p < 0.001) were significantly associated with reduced LVEF. CONCLUSIONS: Our results suggest that wide QRS-T angle is associated with LV remodeling such as enlarged LVEDV or reduced LVEF in patients with advanced CKD.

Formation of amorphous silica nanoparticles and its impact on permeability of fractured granite in superhot geothermal environments.

Superhot geothermal environments in granitic crusts of approximately 400-500 °C are a frontier of geothermal energy. In the development of such environments, there is a concern of a reduction of permeability of fractured granite due to the formation of fine particles of amorphous silica induced by the phase change from subcritical water to supercritical water or superheated steam. However, the formation of silica particles and a resultant reduction in permeability have not been demonstrated to date. Therefore, experiments were conducted on the formation of amorphous silica particles with various combinations of temperature (430-500 °C) and pressure (20-30 MPa), in which the phase change of Si-containing water from liquid to either supercritical fluid or vapor was induced. Amorphous silica nanoparticles occurred under all conditions with smaller particles for higher temperature. The permeability of fractured granite was also observed to decrease significantly within several hours during injection of the particles into rock at 450 °C and 30 MPa under a confining stress of 40 MPa, with slower permeability reduction at a smaller number of particles or in the presence of larger aperture fractures. The present study suggests that the nanoparticles are likely to form and destroy the permeability in superhot geothermal environments, against which countermeasures should be investigated.