Abstract
Lithium-ion transport in cathodes, anodes, solid electrolytes, and through their interfaces plays a crucial role in the electrochemical performance of solid-state lithium-ion batteries. ...Direct visualization of the lithium-ion dynamics at the nanoscale provides valuable insight for understanding the fundamental ion behaviour in batteries. Here, we report the dynamic changes of lithium-ion movement in a solid-state battery under charge and discharge reactions by time-resolved
operando
electron energy-loss spectroscopy with scanning transmission electron microscopy. Applying image denoising and super-resolution via sparse coding drastically improves the temporal and spatial resolution of lithium imaging. Dynamic observation reveals that the lithium ions in the lithium cobaltite cathode are complicatedly extracted with diffusion through the lithium cobaltite domain boundaries during charging. Even in the open-circuit state, they move inside the cathode.
Operando
electron energy-loss spectroscopy with sparse coding is a promising combination to visualize the ion dynamics and clarify the fundamentals of solid-state electrochemistry.
Seawater-driven forward osmosis (FO) is considered to be a novel strategy to concentrate nutrients in treated municipal wastewater for further recovery as well as simultaneous discharge of highly ...purified wastewater into the sea with low cost. As a preliminary test, the performance of FO membranes in concentrating nutrients was investigated by both batch experiments and model simulation approaches. With synthetic seawater as the draw solution, the dissolved organic carbon, phosphate, and ammonia in the effluent from a membrane bioreactor (MBR) treating municipal wastewater were 2.3-fold, 2.3-fold, and 2.1-fold, respectively, concentrated by the FO process with approximately 57% of water reduction. Most of the dissolved components, including trace metals in the MBR effluent, were highly retained (>80%) in the feed side, indicating high water quality of permeate to be discharged. The effect of membrane properties on the nutrient enrichment performance was investigated by comparing three types of FO membranes. Interestingly, a polyamide membrane possessing a high negative charge demonstrated a poor capability of retaining ammonia, which was hypothesized because of an ion exchange-like mechanism across the membrane prompted by the high ionic concentration of the draw solution. A feed solution pH of 7 was demonstrated to be an optimum condition for improving the overall retention of nutrients, especially for ammonia because of the pH-dependent speciation of ammonia/ammonium forms. The modeling results showed that higher than 10-fold concentrations of ammonia and phosphate are achievable by seawater-driven FO with a draw solution to feed solution volume ratio of 2:1. The enriched municipal wastewater contains nitrogen and phosphorous concentrations comparable with typical animal wastewater and anaerobic digestion effluent, which are used for direct nutrient recovery.
•We proposed a novel strategy to enrich nutrients in municipal wastewater using FO.•An ion exchange-like phenomenon was observed in FO with highly charged membrane.•An optimal pH of 7 was identified for retaining nutrients by CTA membrane.•We developed models to simulate the performance of FO on enriching nutrients.
Ni-rich layered cathodes have been used in commercial Li-ion batteries because of their high capacity and low cost. However, they suffer from crack formation at the grain boundaries owing to ...heterogeneous large volume changes during the reactions. To improve their performance, a comprehensive understanding of the grain architecture, Li transport pathways, and phase transitions is essential. Here, we show the correlations between these factors using in situ transmission electron microscopy. The results show that Li ions are extracted through tortuous paths connecting the Li-containing a-b planes in the crystals. Moreover, the grain boundary resistance depends not only on the misorientations of the neighboring grains. Even twins with misorientation angles of 70° are not decisive factors in Li movement. We also show the existence of two-phase separation in single crystals between two hexagonal phases during fast charging. These results provide valuable information for determining the optimal grain architecture and for material design, helping enhance high capacity and high stability.
When two different materials come into contact, mobile carriers redistribute at the interface according to their potential difference. Such a charge redistribution is also expected at the interface ...between electrodes and solid electrolytes. The redistributed ions significantly affect the ion conduction through the interface. Thus, it is essential to determine the actual distribution of the ionic carriers and their potential to improve ion conduction. We succeeded in visualizing the ionic and potential profiles in the charge redistribution layer, or space‐charge layer (SCL), formed at the interface between a Cu electrode and Li‐conductive solid electrolyte using phase‐shifting electron holography and spatially resolved electron energy‐loss spectroscopy. These electron microscopy techniques clearly showed the Li‐ionic SCL, which dropped by 1.3 V within a distance of 10 nm from the interface. These techniques could contribute to the development of next‐generation electrochemical devices.
Interest in the interface: Electron holography and spatially resolved electron energy‐loss spectroscopy were used to directly visualize electric potential and Li‐ion profiles in a Li‐ionic space‐charge layer (SCL) at the interface between an electrode and a solid electrolyte. The potential of the SCL dropped by 1.3 V within 10 nm from the interface.
Forward Osmosis (FO) has been designed and studied for various applications due to the advantages it offers when compared to traditional pressure-driven membrane processes. In our previous study, ...seawater-driven forward osmosis was successfully applied to concentrate nutrients in treated municipal wastewater. In this study, the long-term operational stability and performance of the seawater-driven FO process was investigated by a 2-month continuous operation of bench-top FO reactors. Nitrification inhibition was recommended to maintain the concentration performance of nitrogen by preventing ammonia from being oxidized by microorganisms. With nitrification inhibition, concentration performances of 3- to 4-fold of total phosphorus and 2.1-fold of ammonia were stably achieved at a feed volume reduction of 75%. Membrane fouling, with the active layer of the FO membrane facing the feed solution, had only a mild impact; there was approximately 5% water flux reduction but no significant effect on nutrient enrichment performance. The analytical results by FTIR and SEM-XMA suggested that bio-fouling with a combined structure of bacterial clusters, biopolymers, and slight inorganic scales was the main FO membrane fouling pattern. Furthermore, pre-disinfection performed in feed solution effectively retarded the occurrence of membrane fouling in the FO process.
•High nutrients separation performance was achieved in a long-term operated FO.•Mild fouling impact was observed in the long-term FO without chemical cleaning.•Biofouling was identified as primary FO membrane fouling by municipal wastewater.•FO membrane fouling control mechanism by feed disinfection was explained.
Multiplexed bead array is an application that allows us to quantify multiple ligands simultaneously by using flow cytometry. Glycopeptides are immobilized on multiplexed beads, and the glycan-binding ...specificities of several lectins are determined. This strategy is easy, rapid, and suitable for small amount of samples, and allows the reliable elucidation under the identical condition. Such a technology is useful for analyzing characteristics and functions of lectins.
Gait disturbance is a major symptom of idiopathic normal-pressure hydrocephalus (iNPH) and is assessed by raters of different professions or with different degrees of experience. Agreement studies ...are usually done by two raters or more, and comparisons among multiple groups of raters are rare. In this study, we aimed to examine the agreement among multiple groups of raters on gait patterns and a grading scale through a video-assisted gait analysis in patients with iNPH. Fifteen participants with iNPH were enrolled. Gait was assessed according to seven patterns, including freezing and wide-based gaits. The levels of severity (evident, mild, none) were rated by three groups of raters (two neurosurgeons DR2, three experienced physiotherapists PTe3, and two less experienced physiotherapists PTl2) through a simultaneous video viewing session. Severity of gait disturbance (GSg) was rated using the Japanese iNPH grading scaleiNPHGS, and Krippendorff alpha was computed to assess agreement, with alpha ≥0.667 indicating good agreement and alpha ≥0.8 indicating excellent agreement. For group comparisons, 84%, not 95%, confidence intervals were applied. Among the seven gait patterns in the first assessment, excellent agreement was observed in wide-based and short-stepped gaits in only DR2. Good agreement was observed in four patterns, but the agreement by two groups was in shuffling and wide-based gait. There were no gait patterns showing good agreement among three groups. In the second assessment, excellent agreement was observed in three patterns but no gait patterns showed good agreement between two groups or more. Learning effect was observed only for standing difficulty in DR2. In contrast, good or nearly good agreement on GSg was observed among the three groups with excellent agreement in two groups. Agreement on gait patterns among the three groups of raters was not high, but agreement on the iNPHGS was high, indicating the importance of a precise description facilitating differentiation between neighboring grades.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objectives
To evaluate complex CSF movements and shear stress in patients with idiopathic normal pressure hydrocephalus (iNPH) on four-dimensional (4D) flow MRI.
Methods
Three-dimensional velocities ...and volumes of the reciprocating CSF movements through 12 ROIs from the foramen of Monro to the upper cervical spine were measured in 41 patients with iNPH, 23 patients with co-occurrence of iNPH and Alzheimer’s disease (AD), and 9 age-matched controls, using 4D flow imaging and application. Stroke volume, reversed-flow rate, and shear stress were automatically calculated. Relationships between flow-related parameters and morphological measurements were also assessed.
Results
Stroke volumes, reversed-flow rates, and shear stress at the cerebral aqueduct were significantly higher in patients with iNPH than in controls. Patients with pure iNPH had significantly higher shear stress at the ventral aspect of the cerebral aqueduct than those with co-occurrence of iNPH and AD. The stroke volume at the upper end of the cerebral aqueduct had the strongest association with the anteroposterior diameter of the lower end of the cerebral aqueduct (
r =
0.52). The stroke volume at the foramen of Monro had significant associations with the indices specific to iNPH. The shear stress at the dorsal aspect of the cerebral aqueduct had the strongest association with the diameter of the foramen of Magendie (
r
= 0.52).
Conclusions
Stroke volumes, reversed-flow rates, and shear stress through the cerebral aqueduct on 4D flow MRI are useful parameters for iNPH diagnosis. These findings can aid in elucidating the mechanism of ventricular enlargement in iNPH.
Key Points
• The CSF stroke volume and bimodal shear stress at the cerebral aqueduct were considerably higher in patients with iNPH.
• The patients with pure iNPH had significantly higher shear stress at the ventral aspect of the cerebral aqueduct than those with co-occurrence of iNPH and AD.
• The shear stress at the cerebral aqueduct was significantly associated with the diameter of the foramen of Magendie.
The timed-up-and-go test (TUG) is a popular test for mobility, but it only measures the total time to complete tasks. Recent advances in smartphone technology enables measuring respective times of 6 ...components in the test (Stand, Go, Turn1, Come, Turns and Sit). We examined availability of these data for assessing different gait patterns.
This study enrolled 32 patients with probable idiopathic normal-pressure hydrocephalus and 87 age-matched active participants as controls. All the patients responded positively to cerebrospinal fluid (CSF) removal, among whom 19 underwent surgery with positive outcomes. The TUG was performed using a free smartphone application. The components were automatically detected, and their respective times were computed. Statistical analyses included item cluster analysis.
In the control group, high correlations (r ≥ 0.7) were observed in two pairs of Go and Come, and Turn1 and Turn2, which reflect straight walk and turn. This pattern was lost in the baseline and after CSF removal in the hydrocephalus group. After surgery, the two pairs in the control group regained high correlations. The item cluster analysis showed the pattern changes more clearly.
A smartphone is useful for analyzing gait patterns in the TUG, which can be applicable for various gait disorders.
•Timed-up-and-go test is a popular gait test, but it measures only the total time.•The gait test is composed of Stand, Go, Turn1, Come, Turn2 and Sit.•A smartphone application measures respective times of six components on the test.•The pairs Go and Come, and Turn 1 and Turn2 in the control were 2 major clusters.•This pattern was lost in normal pressure hydrocephalus and restored by surgery.
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