Black valve metal oxides with low oxygen vacancies are identified to be promising for various industrial applications, such as in gas sensing, photocatalysis, and rechargeable batteries, owing to ...their high reducibility and stability, as well as considerable fractions of low‐valent metal species and oxygen vacancies in their lattices. Herein, the nanofiber (NF) of black oxygen‐deficient tungsten trioxide (WO3−x) is presented as a versatile and robust support for the direct growth of a platinum catalyst for oxygen reduction reaction (ORR). The nonstoichiometric, poorly crystallized black WO3−x NFs are prepared by electrospinning the W precursor into NFs followed by their low‐temperature (650 °C) reductive calcination. The black WO3−x NFs have adequate electrical conductivity owing to their decreased bandgap and amorphous structure. Remarkably, the oxygen‐deficient surface (surface O/W = 2.44) facilitates the growth of small Pt nanoparticles, which resist aggregation, as confirmed by structural characterization and computational analysis. The Pt‐loaded black WO3−x NFs outperform the Pt‐loaded crystalline white WO3−x NFs in both the electrochemical ORR activity and the accelerated durability test. This study can inspire the use of oxygen‐deficient metal oxides as supports for other electrocatalysts, and can further increase the versatility of oxygen‐deficient metal oxides.
Black WO3−x nanofibers (NFs) have uniformly distributed amorphous nanoscale fibers and improved conductivity through the reduction process serves as a catalyst support. Pt/black WO3−x NFs show improved durability and high catalytic activity compared to commercialized Pt/C in oxygen reduction reactions, which is applied to hydrogen energy owing to the oxygen vacancies and the high surface area of this support.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Perovskite solar cells are promising candidates for realizing an efficient, flexible, and lightweight energy supply system for wearable electronic devices. For flexible perovskite solar cells, ...achieving high power conversion efficiency (PCE) while using a low-temperature technology for the fabrication of a compact charge collection layer is a critical issue. Herein, we report on a flexible perovskite solar cell exhibiting 12.2% PCE as a result of the employment of an annealing-free, 20 nm thick, amorphous, compact TiO sub(x) layer deposited by atomic layer deposition. The excellent performance of the cell was attributed to fast electron transport, verified by time-resolved photoluminescence and impedance studies. The PCE remained the same down to 0.4 sun illumination, as well as to a 45 degree tilt to incident light. Mechanical bending of the devices worsened device performance by only 7% when a bending radius of 1 mm was used. The devices maintained 95% of the initial PCE after 1000 bending cycles for a bending radius of 10 mm. Degradation of the device performance by the bending was the result of crack formation from the transparent conducting oxide layer, demonstrating the potential of the low-temperature-processed TiO sub(x) layer to achieve more efficient and bendable perovskite solar cells, which becomes closer to a practical wearable power source.
Abstract
Lithium‐ion batteries (LIBs) and beyond‐LIB systems exhibit properties that are determined by electrochemical reactions occurring in their four essential components—the cathode, anode, ...electrolyte, and separator. Advanced analytical methods such as differential electrochemical mass spectrometry (DEMS) can assist in understanding the electrochemical behavior, which can help in advancing battery technologies. Recent studies have shown that the DEMS‐enabled real‐time gas analysis of electrochemical reactions can provide valuable information on aspects such as gaseous reactants or (side) products, which cannot be obtained appropriately through other characterization techniques. This review aims to provide a comprehensive overview of the latest developments and advancements in the use of DEMS as a rapid, operando gas‐monitoring method for advanced rechargeable battery systems. Moreover, the significance of DEMS in current and future battery development is also discussed and insights are provided into the various battery chemistries that can benefit from DEMS applications. This review is intended to help readers understand the potential of DEMS to drive innovation in the battery industry.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Lithium–oxygen (Li–O2) batteries have been intensively investigated in recent decades for their utilization in electric vehicles. The intrinsic challenges arising from O2 (electro)chemistry have ...been mitigated by developing various types of catalysts, porous electrode materials, and stable electrolyte solutions. At the next stage, we face the need to reform batteries by substituting pure O2 gas with air from Earth’s atmosphere. Thus, the key emerging challenges of Li–air batteries, which are related to the selective filtration of O2 gas from air and the suppression of undesired reactions with other constituents in air, such as N2, water vapor (H2O), and carbon dioxide (CO2), should be properly addressed. In this review, we discuss all key aspects for developing Li–air batteries that are optimized for operating in ambient air and highlight the crucial considerations and perspectives for future air-breathing batteries.
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IJS, KILJ, NUK, PNG, UL, UM
OBJECTIVES
We aimed to validate a multi–sensor‐based kiosk (automatically measured Short Physical Performance Battery eSPPB kiosk) that can perform automated measurement of the SPPB.
DESIGN
...Prospective, cross‐sectional study.
SETTING
Rehabilitation clinic of a tertiary‐care hospital.
PARTICIPANTS
Ambulatory outpatients, aged 65 years or older (N = 40).
MEASUREMENTS
The eSPPB kiosk was developed to measure the three components of the SPPB: standing balance, gait speed, and chair stand test with embedded sensors and algorithms. Correlations between the total and component‐specific scores of the eSPPB and manually measured SPPB (mSPPB), assessed by a physical therapist, were assessed. Further, correlations between SPPB parameters and geriatric functional measures were also evaluated.
RESULTS
This study included 40 participants with a mean age of 74.4 ± 6.5 years, a mean total eSPPB score of 10.1 ± 2.1, and a mean total mSPPB score of 10.2 ± 2.1. The intraclass correlation coefficient between the eSPPB and mSPPB total score was 0.97 (P < .001), and the κ agreement was 0.79 (P < .001). The intraclass coefficients between the components of eSPPB and mSPPB were 0.77 (P < .001), 0.88 (P < .001), and 0.99 (P < .001) for standing balance, gait speed, and chair stand test, respectively.
CONCLUSION
The newly developed kiosk might be a viable and efficient method for performing the SPPB in older adults. J Am Geriatr Soc 67:2605–2609, 2019
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
BACKGROUND/OBJECTIVES
To evaluate the long‐term association between a multicomponent intervention program and disability in socioeconomically vulnerable older adults.
DESIGN
This was a nonrandomized ...prospective intervention trial.
SETTING
The setting was a community.
PARTICIPANTS
Participants included older Koreans living alone or receiving government assistance from a low‐income program.
INTERVENTION
The intervention was a 24‐week multicomponent program compromising group exercise, nutritional supplementation, management of depression, deprescribing, and home hazard reduction (n = 187) versus usual care (n = 196).
MEASUREMENTS
The number of dependencies in 17 basic and instrumental activities of daily living was measured every 3 months for 30 months (range: 0–17; greater values indicated worse disability). Inverse probability weighting Poisson regression was used to model the number of dependencies to adjust for confounding bias and higher dropout rates of those with greater disability.
RESULTS
The study population had a mean age of 76 years, and 26% were men. During the 30‐month follow up, 17 died (n = 8, intervention; n = 9, control), 62 (n = 16, intervention; n = 46, control) were institutionalized or received nursing home care, and 34 (n = 15, intervention; n = 19, control) were lost to follow up. After inverse probability weighting, the mean number of dependencies at baseline was 1.21 and 1.29 for the intervention group and the control group, respectively (P = .80). The intervention group had fewer dependencies than the control group, but the difference was attenuated over time: 1.08 versus 1.60 at 6 months (P = .04), 1.29 versus 1.87 at 12 months (P = .03), 1.62 versus 2.17 at 18 months (P = .06), 2.08 versus 2.51 at 24 months (P = .18), and 2.73 versus 2.90 at 30 months (P = .67).
CONCLUSION
A 24‐week multicomponent intervention was associated with a slower progression of disability; however, the diminishing association from 24 months and beyond suggests that reassessment and intervention may be necessary. Due to a lack of randomization, our findings should be interpreted with caution.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
IMPORTANCE The number of geriatric patients who undergo surgery has been increasing, but there are insufficient tools to predict postoperative outcomes in the elderly. OBJECTIVE To design a ...predictive model for adverse outcomes in older surgical patients. DESIGN, SETTING, AND PARTICIPANTS From October 19, 2011, to July 31, 2012, a single tertiary care center enrolled 275 consecutive elderly patients (aged ≥65 years) undergoing intermediate-risk or high-risk elective operations in the Department of Surgery. MAIN OUTCOMES AND MEASURES The primary outcome was the 1-year all-cause mortality rate. The secondary outcomes were postoperative complications (eg, pneumonia, urinary tract infection, delirium, acute pulmonary thromboembolism, and unplanned intensive care unit admission), length of hospital stay, and discharge to nursing facility. RESULTS Twenty-five patients (9.1%) died during the follow-up period (median interquartile range, 13.3 11.5-16.1 months), including 4 in-hospital deaths after surgery. Twenty-nine patients (10.5%) experienced at least 1 complication after surgery and 24 (8.7%) were discharged to nursing facilities. Malignant disease and low serum albumin levels were more common in the patients who died. Among the geriatric assessment domains, Charlson Comorbidity Index, dependence in activities of daily living, dependence in instrumental activities of daily living, dementia, risk of delirium, short midarm circumference, and malnutrition were associated with increased mortality rates. A multidimensional frailty score model composed of the above items predicted all-cause mortality rates more accurately than the American Society of Anesthesiologists classification (area under the receiver operating characteristic curve, 0.821 vs 0.647; P = .01). The sensitivity and specificity for predicting all-cause mortality rates were 84.0% and 69.2%, respectively, according to the model’s cutoff point (>5 vs ≤5). High-risk patients (multidimensional frailty score >5) showed increased postoperative mortality risk (hazard ratio, 9.01; 95% CI, 2.15-37.78; P = .003) and longer hospital stays after surgery (median interquartile range, 9 5-15 vs 6 3-9 days; P < .001). CONCLUSIONS AND RELEVANCE The multidimensional frailty score based on comprehensive geriatric assessment is more useful than conventional methods for predicting outcomes in geriatric patients undergoing surgery.
With evaluation for physical performance, measuring muscle mass is an important step in detecting sarcopenia. However, there are no methods to estimate muscle mass from blood sampling.
To develop a ...new equation to estimate total-body muscle mass with serum creatinine and cystatin C level, we designed a cross-sectional study with separate derivation and validation cohorts. Total body muscle mass and fat mass were measured using dual-energy x-ray absorptiometry (DXA) in 214 adults aged 25 to 84 years who underwent physical checkups from 2010 to 2013 in a single tertiary hospital. Serum creatinine and cystatin C levels were also examined.
Serum creatinine was correlated with muscle mass (P < .001), and serum cystatin C was correlated with body fat mass (P < .001) after adjusting glomerular filtration rate (GFR). After eliminating GFR, an equation to estimate total-body muscle mass was generated and coefficients were calculated in the derivation cohort. There was an agreement between muscle mass calculated by the novel equation and measured by DXA in both the derivation and validation cohort (P < .001, adjusted R2 = 0.829, β = 0.95, P < .001, adjusted R2 = 0.856, β = 1.03, respectively).
The new equation based on serum creatinine and cystatin C levels can be used to estimate total-body muscle mass.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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