Search

• Rapid and high methane uptake was achieved by using CP hydrate seed and pinacolone. • Dominant sH hydrate formation on CP hydrate seeds occurred with no induction time. • Facile methane storage in sH hydrates was verified under all pressure conditions. • Use of pinacolone offers higher methane storage capacity than other promoters. Storing gaseous energy, such as methane, using clathrate hydrates is highly promising due to environment-friendliness, economic feasibility, and mild operating conditions. To develop a feasible hydrate-based methane storage system, pinacolone (PCN) was utilized as a thermodynamic promoter with pre-constructed cyclopentane hydrate seeds under static conditions. Introducing hydrate seeds and PCN resulted in instantaneous nucleation events, leading to the predominant formation of structure H (sH) hydrates containing methane and PCN. In-situ Raman and PXRD analyses supported the prominent formation of sH hydrates, indicating that methane can be easily stored in thermodynamically stable sH hydrates. Kinetic studies at varying pressure conditions (6.0, 4.5, and 3.5 MPa) were also conducted to investigate the impact of PCN under broader operating conditions. Through kinetic evaluations and ex-situ Raman spectra, we confirmed facile methane storage in sH hydrate under all pressure conditions without induction time, overcoming a major hurdle of hydrate-based technologies. Furthermore, the use of PCN resulted in higher methane uptakes compared to other structure Ⅱ hydrate formers owing to cage occupancies of methane molecules in different structures. These findings suggest an efficient way to store methane with a high storage capacity in sH hydrates. [ABSTRACT FROM AUTHOR]

The derivation of an energy-efficient formation process of hydrogen hydrate is a challenging task for hydrogen storage. This work introduces a successive hydrate formation strategy for hydrogen storage within a porous hydrate self-support under static conditions. Sodium dodecyl sulfate (SDS)-induced porous hydrate was prepared as a 'supporting matrix,' and this support enables rapid nucleation and growth of hydrate from the matrix surface. To examine the feasibility of the proposed successive hydrate formation process, SDS solutions were injected into the porous hydrate support in single feed charge and multiple feedings. The successive formation of hydrogen hydrate from SDS solutions through multiple injections enhances the mass transfer of guest molecules throughout the entire reactor, leading to increase in the gas storage capacity and water-to-hydrate conversion by up to 107%. Even with a high water-to-gas volume ratio, the hydrogen storage density in the multiple injection case doubled compared to the single injection case. Regardless of the degree of subcooling, the injection of SDS solutions into the hydrate matrix induced immediate nucleation and extended the reaction regions, as confirmed by numerous reactor experiments and Raman observations. These findings have the potential to advance the use of gas hydrates for hydrogen storage by improving energy efficiency and eliminating the agitation energy cost. • Supporting matrix of porous CP‑hydrogen hydrate is introduced for its rapid growth. • Successive hydrate growth is possible with liquid injected to the self-formed matrix. • Immediate hydrate growth without induction occurs with SDS solution injections. • Successive hydrate growth increases water-to-hydrate conversion significantly. • H 2 enclathration was facilitated even with a small subcooling of 8 K. [ABSTRACT FROM AUTHOR]

Natural gas (NG) is an effective and eco-friendly fossil fuel with regard to reducing CO 2 emission. In this manner, many technologies have been developed to store the NG efficiently, like LNG and CNG. Among them, natural gas hydrates (NGH) emerge as a promising option to replace LNG and CNG, due to their high energy density and mild storage conditions. Nevertheless, vigorous mechanical stirring, which is typically adopted to produce the NGH, requires high energy inputs and short periodic managements from elevated viscosity of the fluids during the production process. In this work, the effective method for synthesizing methane hydrates under a non-stirred system was proposed and evaluated. A commercial melamine sponge, which is cheap, lightweight, and easily accessible, was utilized as a supporting matrix. Additionally, various types of thermodynamic (e.g. , CP (immiscible) and THF (miscible) and kinetic promoters (e.g. , sodium dodecyl sulfate (SDS, surfactant) and l -methionine (L-met, amino acid)) were introduced and assessed in terms of methane storage capacity and kinetic parameters during the long-term 20 cycles of formation-dissociation. These combinations from low dosage of thermodynamic and kinetic promoters (e.g. , CP + SDS, and DIOX + L-met) facilitated immediate nucleation, and high methane uptake was obtained by inducing sequential growth of methane hydrates. Finally, comparing with the CNG technology, it was shown that the mixed hydrates formed with the low-dosage of promoters were profitable in terms of formation and storage conditions. [Display omitted] • CH 4 hydrates were formed with a low dosage of promoters in a sponge over 20 cycles. • L-met was more proper kinetic promoter than SDS over formation/dissociation cycles. • THF and DIOX exhibited more consistent CH 4 uptake kinetics than CP and ECP. • Economic feasibility of the proposed system was compared to conventional CNG process. • Safety, and environmental aspects of the proposed technology were evaluated. [ABSTRACT FROM AUTHOR]

The utilization of clathrate hydrates as a highly promising technology for CO 2 capture and separation is the focus of this review paper. We present an in-depth exploration of hydrate-based CO 2 capture technology, highlighting the use of various additives to enhance the performance of CO 2 hydrate formation, as well as the separation and capture of CO 2 from gas mixtures containing N 2 /H 2 /CH 4. By employing thermodynamic promoters, CO 2 molecules can efficiently occupy hydrate cages under moderate temperature and pressure conditions, while kinetic promoters improve the kinetic properties of hydrate formation. Key performance indicators such as (normalized) gas uptake, t 90 , and separation factor are comprehensively discussed and summarized. Moreover, this review introduces additional applications of CO 2 hydrates, such as their potential in cold energy storage due to their high heat of formation (∆ H d) of approximately 500 kJ/kg, surpassing that of ice at 333 kJ/kg. Additionally, we explore the advantages of the CH 4 -CO 2 replacement method, which offers an energy production alternative without the drawbacks of sediment subsidence and ecosystem destruction. Through a comprehensive review, we emphasize the potential of clathrate hydrates as a promising technology for CO 2 capture and underscore the importance of further research in this area. Ultimately, CO 2 hydrates represent a future direction for mitigating global warming. [Display omitted] • Various thermodynamic and kinetic hydrate promoters were explored. • Gas separation performances of hydrate-based technologies were summarized. • Potential of cold energy storage material with high dissociation enthalpy was addressed. • Various studies of CH 4 -CO 2 replacement were introduced. [ABSTRACT FROM AUTHOR]

Objective This study aims to evaluate the prognosis of single cantilevered restoration, of which the cantilever length is less than 6 mm, retrospectively. Methods This study targeted 33 patients (20 males, 13 females) who were treated with total 35 single cantilevered restorations (mesial direction or distal direction) combined with implant installations from May 2004 to December 2012. All of the implant prostheses were single implant–supported and cantilevered(cantilever lengths were over 3 mm). Results The length of cantilevers ranged from 3.01 mm to 5.99 mm. All implants survived during the average of 47.72 months of observation period. The success rate of implants was 94.29%. The complications were peri-implantitis (8.57%) with symptoms such as swelling and bleeding and prosthetic complications (22.9%) such as screw loosening, abutment hex fracture, screw locking, and crown fracture. There was an average of 0.04 ± 0.14 mm peri-implant alveolar bone loss at 1 year after loading and 0.16 ± 0.51 mm at final observation. Conclusions Although single cantilevered restoration shorter than 6 mm does not induce crestal bone loss around the implant, several complications such as peri-implantitis and mechanical complications could still remain. [ABSTRACT FROM AUTHOR]

Background and Aims Elevated circulating insulin is associated with increased risk of recurrence and cancer mortality in early-stage colorectal cancer (CRC). We conducted a randomized controlled trial to determine the effect of a 12-week home-based exercise program on fasting insulin, adipocytokines, and physical function in CRC survivors. Methods One hundred and twenty-three stage II-III CRC patients were randomly assigned to either a home-based exercise ( n = 62) or standard care control group ( n = 61) for 12 weeks. Home-based exercise consisted of aerobic and resistance training, with a goal of obtaining ≥ 18 metabolic equivalent task (MET)-h/wk. Participants in the exercise group were instructed to participate in > 18 MET-h/wk. of aerobic and resistance exercise while the participants in the control group were asked to maintain their usual daily activity. The primary outcome was fasting insulin levels. Secondary outcomes were adiponectin, TNF-α levels and 6 min walk distance from baseline to post-intervention. Results After the 12-weeks, moderate-vigorous physical activity participation increased from 9.1 ± 14.7 MET-h/wk. to 26.6 ± 21.7 MET-h/wk. in the exercise group, with no change in the control group ( p < 0.01 for group and time interaction). Circulating insulin level decreased by 1 μU/ml (6.0 ± 3.9 vs. 5.0 ± 3.5, p = 0.009) in the exercise group with no change in the control group ( p = 0.022 for group and time interaction). A similar trend was observed in TNF-α ( p = 0.030 for group and time interaction). Six minute walk distance increased by 25.2 m in the exercise group with no change in the control group ( p = 0.061 for group and time interaction). Conclusions The 12 week home-based exercise program increased level of physical activity and decreased circulating insulin levels in CRC survivors. [ABSTRACT FROM AUTHOR]

The slow formation rate of hydrogen clathrate hydrate is one of the most challenging factors impeding the utilization of clathrate hydrate as a hydrogen storage media. Blending of a hydrate seed solution and a liquid phase thermodynamic promoter is introduced in this study to promote the formation of hydrogen hydrates for safe hydrogen storage. Cyclopentane hydrate seeds induced instantaneous growth of cyclopentane + hydrogen mixed hydrates by providing nucleation sites for hydrate formation. Increasing the amount of hydrate seeds accelerated the formation rate of hydrates at the early stage of the reaction because the surface area of hydrate crystals increased. However, the total storage capacity was not so high because the diffusion of hydrogen molecules into empty cages of pre-constructed hydrate crystals was difficult. This diffusion limitation was overcome by the addition of the cyclopentane liquid phase promoter for the simultaneous formation of cyclopentane and hydrogen hydrates with their porous vertical growth. Tetrahydrofuran, one of the most commonly used organic promoters for hydrogen hydrates, was not suitable for the blended hydrate seed and liquid promoter system because its miscibility with water hindered the formation of hydrogen-bond cages and did not induce vertical growth of porous hydrates. This study provides insights into the role of liquid promoter blended with hydrate seeds in enhancing formation of hydrogen hydrates as sustainable hydrogen storage. • Enclathration of H 2 is induced with liquid promoters in sII hydrate seed solution. • H 2 is well enclathrated with simultaneous growth of C P-H 2 hydrate. • CP liquid is more profitable for seed-induced H 2 hydrate formation than THF liquid. • Water-insoluble CP liquid makes the growth morphology of H 2 hydrate asymmetric. [ABSTRACT FROM AUTHOR]

Rebamipide, a mucosal-protective agent, is used clinically for treatment of gastritis and peptic ulcers induced by Helicobacter pylori ( H. pylori ) which is associated with increased risk of gastric cancer. Although rebamipide is known to inhibit the growth of gastric cancer cells, the action mechanisms of rebamipide in gastric carcinogenesis remains elusive. Here, we show that rebamipide suppresses H. pylori CagA-induced β-catenin and its target cancer-initiating cells (C-IC) marker gene expression via upregulation of miRNA-320a and -4496. Rebamipide attenuated in vitro self-renewal capacity of H. pylori CagA-infected gastric C-IC via modulation of miRNA-320a/-4496-β-catenin signaling axis. Moreover, rebamipide enhanced sensitivity to chemotherapeutic drugs in CagA-expressed gastric C-IC. Furthermore, rebamipide suppressed tumor-initiating capacity of gastric C-IC, probably via suppression of CagA-induced C-IC properties. These data provide novel insights for the efficacy of rebamipide as a chemoprotective drug against H. pylori CagA-induced carcinogenic potential. [ABSTRACT FROM AUTHOR]

The hydrate formation rate and conversion yield are essential factors for hydrate-based gas storage and accordingly various thermodynamic and kinetic promoters have been extensively investigated. However, for hydrate-based CO 2 capture, carbonate ions induced from dissolved CO 2 in water hinder the performance of kinetic promoters (e.g., sodium dodecyl sulfate (SDS)). In this work, we introduce a superabsorbent polymer (SAP) matrix that provides an extremely high interfacial area between a sorbed tetrahydrofuran (THF) solution and gaseous CO 2. The SAP enhanced the formation rate of binary THF-CO 2 hydrate, despite the absence of mechanical agitation. We varied the concentration of THF, temperature, reactor volume, and the ratio of solution to the reactor for a systematic study and explored their effects on the CO 2 storage capacity and the induction time. We observed that highly concentrated THF and a larger reactor with a high gas-liquid contact area enhanced the CO 2 storage capacity and formation rate. Raman and PXRD spectroscopic analyses were employed to investigate the guest distribution and crystalline structure of the THF-CO 2 hydrates synthesized under various conditions. All the binary hydrates were structure-II (sII) hydrates, and there was no pure structure-I (sI) CO 2 hydrate. Based on the spectroscopic results, we developed a theoretical model that could calculate the amount of enclathrated CO 2 and dissolved CO 2 in liquid phases separately. This work reveals that SAP has excellent potential for rapid CO 2 capture in hydrate media with a high water-to-hydrate conversion ratio. • Dispersion of binary THF-CO 2 hydrates in SAP enhanced CO 2 storage capacity. • The size effect of solution/reactor on CO 2 uptake was investigated. • CO 2 in hydrate/liquid phase was distinguished for the precise capacity calculation. [ABSTRACT FROM AUTHOR]

Abstract: Solid oxide fuel cells (SOFCs) have begun to attract attention because of their low emissions, high-energy conversion efficiencies, and flexibility with various fuels. However, it is very difficult to produce large area unit cells with a high degree of flatness using tape-casting and co-firing. Therefore, the understanding of unit cell behavior during co-firing is very important in the manufacturing field of SOFCs. The densification-based finite element method (DFEM) was selected for modeling and analysis of the co-firing behavior of a SOFC unit cell. The DFEM corroborated the experimental results. The anode support thickness mainly affected the camber among the SOFC components. When applying compressive force during co-firing, the camber was minimized when the loading density was near 12 g cm−2, and the deformation rate increased rapidly as the compressive loading density increased. Additionally, the application of the compressive force affected the internal stress distribution. The co-fired cell with an applied optimal compressive force showed homogeneous stress distribution. [Copyright &y& Elsevier]

Abstract: Phospholipase D (PLD) has emerged as a critical element in the cell growth signaling. Despite extensive information regarding the regulation of PLD activity in cell survival, the signaling mechanisms that regulate PLD expression in cancer remains poorly understood. Here we investigate that platelet derived growth factor (PDGF) increases PLD1 but not PLD2 expression via Ras–ERK/PI3K–NFκB signaling cascade in SK-BR3 breast cancer cells. The two NFκB-binding sites are functionally critical for transcriptional activation of PLD1 induced by PDGF. Furthermore, depletion of PLD1 using siRNA significantly abolished PDGF-induced upregulation of matrix metalloproteinase-2 or -9 and invasion of breast cancer cells. Thus, we propose that PDGF-induced PLD1 expression via NFκB signaling pathway might contribute to carcinogenesis. [Copyright &y& Elsevier]

Summary: In the present study, we used the SOD1G93A mutant transgenic mice as an in vivo model of amyotrophic lateral sclerosis (ALS) and performed immunohistochemical studies to investigate the changes of insulin-like growth factor-binding protein 4 (IGFBP4) in the central nervous system. Decreased expression of IGFBP4 was obvious in the cerebral cortex, hippocampus, cerebellar cortex and inferior olive of SOD1G93A transgenic mice. In the cerebral cortex, there was a significant decrease in IGFBP4 immunoreactivity in the pyramidal cells. In the hippocampal formation, IGFBP4 immunoreactivity was also decreased in the pyramidal cells of CA1–3 areas and the granule cells of dentate gyrus. In the cerebellar cortex, IGFBP4 immunoreactivity was prominent in the granular layer in wtSOD1 transgenic mice, compared to that in SOD1G93A transgenic mice. IGFBP4 immunoreactivity was decreased in the inferior olive of SOD1G93A transgenic mice. This study, showing decreased IGFBP4 in different brain regions of SOD1G93A transgenic mice, may provide clues to understanding the differential susceptibility of neural structures in ALS, suggesting a role of IGFBP4 in an abnormality of cognitive and/or motor function in ALS. The mechanisms and functional implications of these decreases require elucidation. [Copyright &y& Elsevier]

• What is the primary question addressed by this study? We aimed to investigate the mediating effect of ICV on the association between educational attainment in early life and regional brain volume in later life. • What is the main finding of this study? Our results showed that the effect of education on regional brain volume was significantly mediated by ICV in both men and women. The indirect (mediated via ICV) effect of education on brain volume amounted to 75% of the total effect in the hippocampus (p < 0.001) and 100% in the frontal and insular gray matter (p < 0.001). • What is the meaning of the finding? Our study demonstrated that the association between educational attainment in early life and regional brain volume in later life was largely mediated by ICV. Attention should be given to the effect of educational attainment and ICV on regional brain size in adults as a measurable resilience effect in brain aging. Brain structure and function change with age. Both educational attainments, a proxy for cognitive reserve, and intracranial volume (ICV), a proxy for brain reserve, could contribute to resilience against degenerative change in the brain with aging. Whether the effect of educational attainment on regional brain volume in adults is mediated by ICV is yet unclear. We aimed to investigate the direct and indirect effects (mediated through ICV) of education in early life on regional brain volume in later life. We investigated the association between ICV and education level and regional brain volume in adults using magnetic resonance imaging scans of 1,731 individuals from multicenter studies. The mediation effect of ICV was analyzed to determine the association between educational attainment at an earlier age and regional brain volume in adults. Our results showed that the effect of education on regional brain volume was significantly mediated by ICV in both men and women. The indirect (mediated via ICV) effect of education on brain volume amounted to 75% of the total effect in the hippocampus (p < 0.001) and 100% in the frontal and insular gray matter (p < 0.001). Our study demonstrated that the association between educational attainment in early life and regional brain volume in later life was largely mediated by ICV. Attention should be given to the effect of educational attainment and ICV on regional brain size in adults as a measurable resilience effect in brain aging. [ABSTRACT FROM AUTHOR]

Abstract: The current collector for the molten carbonate fuel cell (MCFC) is manufactured from the sheet metal forming process. After the forming process, the current collector is bent resulting in a specific curvature (κ i) in the direction in which trapezoidal protrusions are formed due to springback. In the stack of the MCFC, small deformation of the current collector can bring about defects in the electrolyte, non-uniform contact and difficulties in assembling the stack. Therefore, the curvature of the current collector should be minimized in order to reduce defects which can cause critical damage in the long-term operation. In order to straighten the current collector, the levelling process using three rolls was employed. In this work, a simple and effective method for designing the levelling process was proposed. An analytic model and the finite element analysis were used in combination. The optimal curvature minimizing the resultant curvature and the resultant moment of the current collector down to zero was calculated from the bending moment–curvature relationship. The bending moment–curvature relationship of the current collector was determined from the finite element analysis of uniform bending using the simulation results of the three-stage forming process. In the analytic model based on curvature integration method, the proper roll arrangement corresponding to the optimal curvature was calculated. Experiments were conducted using the calculated roll arrangement. The current collector was levelled nearly flat using the levelling process. After the levelling process, the flattened current collector was easily assembled with a centre plate and ensuring uniform contact with the electrolyte. [Copyright &y& Elsevier]

The efficiency of two prototype catalysis systems using palladium (Pd)-coated microparticles was investigated with regard to the recovery and recyclability of the catalytic particles. One such system was the interface-adsorption method, in which polymer particles coated with Pd nanoparticles strongly and irreversibly attach to the oil-water interface. Due to the irreversible adsorption of the catalytic particles to the interface, particle loss was completely prevented while mixing the aqueous solution and while collecting the products. The other system was based on the magnetic field-associated particle recovery method. The use of polymeric microparticles containing Pd nanoparticles and magnetite nanoparticles accelerated the sedimentation of the particles in the aqueous phase by applying a strong magnetic field, consequently suppressing drainage of the particles from the reactor along the product stream. Upon multiple runs of the catalytic reactions, it was found that conversion does not change significantly, demonstrating the excellent recyclability and performance efficiency in the catalytic processes. [ABSTRACT FROM AUTHOR]