Background Recent studies have reported improved diastolic function in patients administered sodium-glucose cotransporter 2 inhibitors (SGLT2i). We aimed to investigate the effect of dapagliflozin on ...left ventricular (LV) diastolic function in a diabetic animal model and to determine the molecular and cellular mechanisms underlying its function. Methods A total of 30 male New Zealand white rabbits were randomized into control, diabetes, or diabetes+dapagliflozin groups (n = 10/per each group). Diabetes was induced by intravenous alloxan. Cardiac function was evaluated using echocardiography. Myocardial samples were obtained for histologic and molecular evaluation. For cellular evaluation, fibrosis-induced cardiomyoblast (H9C2) cells were obtained, and transfection was performed for mechanism analysis (serum and glucocorticoid-regulated kinase 1 (SGK1) signaling analysis). Results The diabetes+dapagliflozin group showed attenuation of diastolic dysfunction compared with the diabetes group. Dapagliflozin inhibited myocardial fibrosis via inhibition of SGK1 and epithelial sodium channel (ENaC) protein, which was observed both in myocardial tissue and H9C2 cells. In addition, dapagliflozin showed an anti-inflammatory effect and ameliorated mitochondrial disruption. Inhibition of SGK1 expression by siRNA decreased and ENaC and Na+/H+ exchanger isoform 1 (NHE1) expression was confirmed as significantly reduced as siSGK1 in the diabetes+dapagliflozin group. Conclusions Dapagliflozin attenuated left ventricular diastolic dysfunction and cardiac fibrosis via regulation of SGK1 signaling. Dapagliflozin also reduced macrophages and inflammatory proteins and ameliorated mitochondrial disruption. Keywords: Heart failure, Diabetes mellitus, Sodium-glucose cotransporter 2 inhibitor, Left ventricular diastolic function
Biofouling in membrane bioreactors (MBRs), which is defined as the unwanted accumulation of microorganisms on the membrane surface, has been intensively studied for more than two decades. However, it ...remains a critical limiting factor to the more widespread use of MBR for wastewater treatment. The concept of quorum sensing (QS) / quorum quenching (QQ) was proposed as an anti-fouling strategy for MBRs in 2002 and the first paper on that issue was published in 2009. Since then, many studies have demonstrated and proved the potential of QQ for biofouling control in MBR through various means. The evolution of QQ-MBR has had a run of eight years in terms of QQ-microorganisms, QQ-media, and the size of the QQ-MBRs tested. This review provides an overview on the QS/QQ studies related to the elucidation and control of biofouling in MBRs, including the identification of QS signals, the isolation of QS signal producing or degrading microorganisms, and various engineering approaches to apply enzymatic or bacterial QQ in the form of QQ-media to mitigate membrane biofouling. The challenges confronting these applications and future directions of QQ-based biofouling control strategies for MBR are discussed.
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•Origin and evolution of QQ technology for biofouling control in MBRs.•Fundamentals of QS and QQ in the context of MBRs.•Comparison of the inhibition of biofouling between conventional- and QQ-MBRs.•Development and evolution of QQ-media in QQ-MBRs.•Confronting challenges and future directions of QQ-MBRs.
Information visualization has traditionally limited itself to 2D representations, primarily due to the prevalence of 2D displays and report formats. However, there has been a recent surge in ...popularity of consumer grade 3D displays and immersive head-mounted displays (HMDs). The ubiquity of such displays enables the possibility of immersive, stereoscopic visualization environments. While techniques that utilize such immersive environments have been explored extensively for spatial and scientific visualizations, contrastingly very little has been explored for information visualization. In this paper, we present our considerations of layout, rendering, and interaction methods for visualizing graphs in an immersive environment. We conducted a user study to evaluate our techniques compared to traditional 2D graph visualization. The results show that participants answered significantly faster with a fewer number of interactions using our techniques, especially for more difficult tasks. While the overall correctness rates are not significantly different, we found that participants gave significantly more correct answers using our techniques for larger graphs.
Semiconductors are the basis of many vital technologies such as electronics, computing, communications, optoelectronics, and sensing. Modern semiconductor technology can trace its origins to the ...invention of the point contact transistor in 1947. This demonstration paved the way for the development of discrete and integrated semiconductor devices and circuits that has helped to build a modern society where semiconductors are ubiquitous components of everyday life. A key property that determines the semiconductor electrical and optical properties is the bandgap. Beyond graphene, recently discovered two-dimensional (2D) materials possess semiconducting bandgaps ranging from the terahertz and mid-infrared in bilayer graphene and black phosphorus, visible in transition metal dichalcogenides, to the ultraviolet in hexagonal boron nitride. In particular, these 2D materials were demonstrated to exhibit highly tunable bandgaps, achieved via the control of layers number, heterostructuring, strain engineering, chemical doping, alloying, intercalation, substrate engineering, as well as an external electric field. We provide a review of the basic physical principles of these various techniques on the engineering of quasi-particle and optical bandgaps, their bandgap tunability, potentials and limitations in practical realization in future 2D device technologies.
Quorum quenching (QQ) has recently been acknowledged to be a sustainable antifouling strategy and has been investigated widely using lab-scale membrane bioreactor (MBR) systems. This study attempted ...to bring this QQ-MBR closer to potential practical application. Two types of pilot-scale QQ-MBRs with QQ bacteria entrapping beads (QQ-beads) were installed and run at a wastewater treatment plant, feeding real municipal wastewater to test the systems' effectiveness for membrane fouling control and thus the amount of energy savings, even under harsh environmental conditions. The rate of transmembrane pressure (TMP) build-up was significantly mitigated in QQ-MBR compared to that in a conventional-MBR. Consequently, QQ-MBR can substantially reduce energy consumption by reducing coarse bubble aeration without compromising the effluent water quality. The addition of QQ-beads to a conventional MBR substantially affected the EPS concentrations, as well as microbial floc size in the mixed liquor. Furthermore, the QQ activity and mechanical stability of QQ-beads were well maintained for at least four months, indicating QQ-MBR has good potential for practical applications.
Abstract
Polaritons in two-dimensional materials provide extreme light confinement that is difficult to achieve with metal plasmonics. However, such tight confinement inevitably increases optical ...losses through various damping channels. Here we demonstrate that hyperbolic phonon polaritons in hexagonal boron nitride can overcome this fundamental trade-off. Among two observed polariton modes, featuring a symmetric and antisymmetric charge distribution, the latter exhibits lower optical losses and tighter polariton confinement. Far-field excitation and detection of this high-momenta mode become possible with our resonator design that can boost the coupling efficiency via virtual polariton modes with image charges that we dub ‘image polaritons’. Using these image polaritons, we experimentally observe a record-high effective index of up to 132 and quality factors as high as 501. Further, our phenomenological theory suggests an important role of hyperbolic surface scattering in the damping process of hyperbolic phonon polaritons.
This article introduces a 192-Gb 896-GB/s 12-high stacked third-generation high-bandwidth memory (HBM3 DRAM) with low power consumption and high-reliability traits. New design schemes and features, ...including internal low-voltage signaling, center strobe calibration, through-silicon via (TSV) auto-calibration, a symbol-correcting in-DRAM ECC, and machine-learning-based layout optimization, allow large amounts of data transfers among the vertically stacked base and core dies with limited delay mismatch or SI degradation, as well as reduced power consumption from low-voltage swings. Experimental results confirm 896-GB/s bandwidth operations at 1.0-V voltage conditions with up to 15% improved power efficiency.
•The performance analysis of CO2 capture process using multi-amines was studied.•DETA in a conventional process achieved lower energy consumption of 8.57% than MEA.•CSS modification using DETA ...achieved further energy improvement, 2.962 GJ/tonCO2.•Number of amine moles and desorption rate in stripper were critical for efficiency.•Potential of multi-amines was suggested for post-combustion CO2 capture process.
Although many novel multi-amine solvents with high CO2 solubility were reported, they have not yet been evaluated for the performance in CO2 absorption processes. In this study, the efficiency and inside profile of the packed-column CO2 absorption process using a novel multi-amine solvent were investigated by using a mathematical model. Three amine solvents were selected: 2-(2-aminoethylamino)-ethanol (AEEA) and diethylenetriamine (DETA) as multi-amine solvents and monoethanolamine (MEA) as a reference. Based on the 90% capture efficiency of flue gas CO2 from a coal-fired power plant, a sensitivity analysis using the liquid-to-gas ratio was conducted to minimize the energy consumption for CO2 capture. Based on the utilization of the same 30 wt% solvent, the lowest reboiler thermal energy achieved by the process using DETA was 3.242 GJ/tonCO2, which was 8.57% lower than that obtained when MEA was employed. In contrast, the process using AEEA required 7.04% higher energy than MEA. In the process modified by rich-solvent split for further enhancing efficiency, the DETA process could achieve 2.962 GJ/tonCO2, which reduced the reboiler duty by 16.8% from the MEA process. The CO2 capture performance of absorbents could not be evaluated not only by the absorption rate and capacity. Owing to the larger molecular weight of multi-amines than MEA, the performance of capture and regeneration was discussed with respect to the amine properties and number of amine moles in the solution. A well-selected multi-amine for a modified process configuration has considerable potential for improving the energy efficiency of CO2 capture.
In chemical absorption processes for carbon capture, one of the main technical challenges is to overcome its high energy requirement for solvent regeneration. A techno-economic analysis was conducted ...on various modified carbon capture processes using a 30 wt% monoethanolamine (MEA) solvent. Five configurations of a stripper modified with two or more components of lean vapor compression (LVC), cold solvent split (CSS), and stripper overhead compression (SOC) were designed. Each configuration aimed to reduce the total equivalent work (Wtotal) via heat integration between the condenser and reboiler. The performance was compared with those of conventional and single-modified configurations based on 90% carbon capture from a coal-fired power plant. Compared with the reference results of a pilot plant operation, the thermal energy required from a reboiler could be reduced by 8.1–32.8% through the modified configurations. The developed combined configurations suggested that the Wtotal could be reduced by up to 9.0%, and the operating cost could be saved by up to 10.2%. Although an increase in capital costs is inevitable for process modifications, the advanced configurations can be considered as an alternative to the reference process because energy and operating costs are reduced.
•Techno-economic analysis of post-combustion carbon capture processes was conducted.•Comparative analysis was performed on eight configurations of a 300-MW power plant.•Strippers with two or more of LVC, CSS and SOC were developed to save energy.•Total equivalent work was saved by 9.0% and operational expenditure by 10.2%.•In terms of SIR, developed processes can be alternative to the conventional process.
An acoustic plasmon mode in a graphene-dielectric-metal structure has recently been spotlighted as a superior platform for strong light-matter interaction. It originates from the coupling of graphene ...plasmon with its mirror image and exhibits the largest field confinement in the limit of a sub-nm-thick dielectric. Although recently detected in the far-field regime, optical near-fields of this mode are yet to be observed and characterized. Here, we demonstrate a direct optical probing of the plasmonic fields reflected by the edges of graphene via near-field scattering microscope, revealing a relatively small propagation loss of the mid-infrared acoustic plasmons in our devices that allows for their real-space mapping at ambient conditions even with unprotected, large-area graphene grown by chemical vapor deposition. We show an acoustic plasmon mode that is twice as confined and has 1.4 times higher figure of merit in terms of the normalized propagation length compared to the graphene surface plasmon under similar conditions. We also investigate the behavior of the acoustic graphene plasmons in a periodic array of gold nanoribbons. Our results highlight the promise of acoustic plasmons for graphene-based optoelectronics and sensing applications.
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