Coupling-dependent metabolic ultradian rhythms in confluent cells.

Ultradian rhythms in metabolism and physiology have been described previously in mammals. However, the underlying mechanisms for these rhythms are still elusive. Here, we report the discovery of temperature-sensitive ultradian rhythms in mammalian fibroblasts that are independent of both the cell cycle and the circadian clock. The period in each culture is stable over time but varies in different cultures (ranging from 3 to 24 h). We show that transient, single-cell metabolic pulses are synchronized into stable ultradian rhythms across contacting cells in culture by gap junction-mediated coupling. Coordinated rhythms are also apparent for other metabolic and physiological measures, including plasma membrane potential (Δψp), intracellular glutamine, α-ketoglutarate, intracellular adenosine triphosphate (ATP), cytosolic pH, and intracellular calcium. Moreover, these ultradian rhythms require extracellular glutamine, several different ion channels, and the suppression of mitochondrial ATP synthase by α-ketoglutarate, which provides a key feedback mechanism. We hypothesize that cellular coupling and metabolic feedback can be used by cells to balance energy demands for survival.

The application of 5E rehabilitation management mode in the nursing of patients with aortic dissection complicated by obstructive sleep apnea.

OBJECTIVE: This study was designed to explore the effect of 5E rehabilitation mode (encouragement, education, exercise, employment, and evaluation) in patients with aortic dissection (AD) complicated by obstructive sleep apnea (OSA). METHODS: Patients with Stanford type B AD (TBAD) complicated by OSA were admitted to Guangdong Provincial People's Hospital from January 2019 to December 2020. They were randomly divided into an experimental group and a control group. After discharge, patients in the control group were given routine nursing and follow-up education, whereas patients in the experimental group were given 5E rehabilitation management mode-based nursing and follow-up education. Upon the nursing intervention, the differences in polysomnography (PSG) parameters, medication adherence, quality of life, blood pressure, and heart rate of patients between the two groups were compared. Logistic regression analysis was performed to evaluate the risk factors for the occurrence of adverse aortic events. RESULTS: A total of 89 patients were enrolled, 49 in the experimental group and 40 in the control group. After the intervention, the control of heart rate, systolic blood pressure, medication adherence, PSG parameters, and quality of life scores in the experimental group were significantly better than those in the control group (P<0.05). The incidence of adverse aortic events including aortic rupture and progressive aortic dilation in the experimental group was significantly lower than that in the control group (P < 0.05). Logistic regression analysis revealed that acute TBAD [odds ratio (OR) = 15.069; 95%confidence interval (CI), 1.738-130.652; P=0.014], history of chronic kidney disease (OR=10.342; 95%CI, 1.056-101.287; P=0.045), and apnea hypopnea index (AHI) ≥ 30 (OR=2.880; 95%CI, 1.081-9.51; P=0.036) were adverse factors affecting adverse aortic events; while 5E rehabilitation management mode (OR=0.063; 95%CI, 0.008-0.513; P=0.010) was a favorable factor for occurrence of adverse aortic events. CONCLUSION: The findings suggest that continuous nursing based on information carrier 5E rehabilitation management significantly enhanced medication adherence, improved patients' overall quality of life, and decreased the incidence of adverse aortic events in patients TBAD patients and OSA.

Effects of new hypoglycemic drugs on cardiac remodeling: a systematic review and network meta-analysis.

BACKGROUND: In recent years, the incidence of diabetes mellitus has been increasing annually, and cardiovascular complications secondary to diabetes mellitus have become the leading cause of death in diabetic patients. Considering the high incidence of type 2 diabetes (T2DM) combined with cardiovascular disease (CVD), some new hypoglycemic agents with cardiovascular protective effects have attracted extensive attention. However, the specific role of these regimens in ventricular remodeling remains unknown. The purpose of this network meta-analysis was to compare the effects of sodium glucose cotransporter type 2 inhibitor (SGLT-2i), glucagon-like peptide 1 receptor agonist (GLP-1RA) and dipeptidyl peptidase-4 inhibitor (DPP-4i) on ventricular remodeling in patients with T2DM and/or CVD. METHODS: Articles published prior to 24 August 2022 were retrieved in four electronic databases: the Cochrane Library, Embase, PubMed, and Web of Science. This meta-analysis included randomized controlled trials (RCTs) and a small number of cohort studies. The differences in mean changes of left ventricular ultrasonic parameters between the treatment and control groups were compared. RESULTS: A total of 31 RCTs and 4 cohort studies involving 4322 patients were analyzed. GLP-1RA was more significantly associated with improvement in left ventricular end-systolic diameter (LVESD) [MD = -0.38 mm, 95% CI (-0.66, -0.10)] and LV mass index (LVMI) [MD = -1.07 g/m2, 95% CI (-1.71, -0.42)], but significantly decreased e' [MD = -0.43 cm/s 95% CI (-0.81, -0.04)]. DPP-4i was more strongly associated with improvement in e' [MD = 3.82 cm/s, 95% CI (2.92,4.7)] and E/e'[MD = -5.97 95% CI (-10.35, -1.59)], but significantly inhibited LV ejection fraction (LVEF) [MD = -0.89% 95% CI (-1.76, -0.03)]. SGLT-2i significantly improved LVMI [MD = -0.28 g/m2, 95% CI (-0.43, -0.12)] and LV end-diastolic diameter (LVEDD) [MD = -0.72 ml, 95% CI (-1.30, -0.14)] in the overall population, as well as E/e' and SBP in T2DM patients combined with CVD, without showing any negative effect on left ventricular function. CONCLUSION: The results of the network meta-analysis provided high certainty to suggest that SGLT-2i may be more effective in cardiac remodeling compared to GLP-1RA and DPP-4i. While GLP-1RA and DPP-4i may have a tendency to improve cardiac systolic and diastolic function respectively. SGLT-2i is the most recommended drug for reversing ventricular remodeling in this meta-analysis.

Exposure to citrinin induces DNA damage, autophagy, and mitochondria dysfunction during first cleavage of mouse embryos.

Citrinin (CTN) is a mycotoxin, which is isolated from Penicillium citrinum and widely existed in the contaminated feeds. It is reported that CTN is toxic to heart, liver, and reproductive system. Previous studies indicated that CTN induced apoptosis in oocytes and embryos. In this study, we reported the potential causes of CTN on embryo development. Our results showed that 40 µM CTN exposure significantly reduced the first cleavage of mouse embryos, showing with the low rate of 2-cell embryos. We found that CTN induced DNA damage, showing the higher positive γH2A.X signals. Autophagy was occurred since more LC3 positive autophagosomes were found in the cytoplasm. This could be confirmed by the enhanced lysosome function, since higher accumulated lysosome distribution were found and LAMP2 was also increased under CTN exposure. Besides, we showed that mitochondria distribution was disturbed, indicating that CTN could disrupt mitochondria function, which could be the possible reason for the oxidative stress and apoptosis in CTN-exposed embryos. In conclusion, our study showed that CTN exposure had adverse effects on the early embryo development during first cleavage through its effects on the induction of DNA damage, autophagy, and mitochondria dysfunction.

Direct Observation of Oxygen Dissociation on Non-Stoichiometric Metal Oxide Catalysts.

Oxygen dissociation on metal oxides is a key reaction step, limiting the efficiency of numerous technologies. The complexity of the multi-step oxygen reduction reaction (ORR) makes it difficult to investigate the oxygen dissociation step independently. Direct observation of the oxygen dissociation process is described, quantitatively, on perovskites La0.6 Sr0.4 Co0.2 Fe0.8 O3-δ and (La0.8 Sr0.2 )0.95 MnO3±Î´ , using gas-phase isotope-exchange with a 1:1 16 O2 :18 O2 ratio. Oxygen transport mechanisms between gas-surface reactions and surface-bulk exchange are deconvoluted. Our findings show that regardless of participation of lattice oxygen, La0.6 Sr0.4 Co0.2 Fe0.8 O3-δ is better at oxygen dissociation than (La0.8 Sr0.2 )0.95 MnO3±Î´ . Heteroexchange, involving lattice oxygen, dominates on La0.6 Sr0.4 Co0.2 Fe0.8 O3-δ . In contrast, (La0.8 Sr0.2 )0.95 MnO3±Î´ shows both homoexchange and heteroexchange, with the latter only happening above 600 °C. Using a 1:1 isotope mixture, a simple method is presented for separation of the oxygen dissociation step from the overall ORR.

A Photostable Silicon Rhodamine Platform for Optical Voltage Sensing.

This paper describes the design and synthesis of a photostable, far-red to near-infrared (NIR) platform for optical voltage sensing. We developed a new, sulfonated silicon rhodamine fluorophore and integrated it with a phenylenevinylene molecular wire to create a Berkeley Red Sensor of Transmembrane potential, or BeRST 1 ("burst"). BeRST 1 is the first member of a class of far-red to NIR voltage sensitive dyes that make use of a photoinduced electron transfer (PeT) trigger for optical interrogation of membrane voltage. We show that BeRST 1 displays bright, membrane-localized fluorescence in living cells, high photostability, and excellent voltage sensitivity in neurons. Depolarization of the plasma membrane results in rapid fluorescence increases (24% ΔF/F per 100 mV). BeRST 1 can be used in conjunction with fluorescent stains for organelles, Ca(2+) indicators, and voltage-sensitive fluorescent proteins. In addition, the red-shifted spectral profile of BeRST 1, relative to commonly employed optogenetic actuators like ChannelRhodopsin2 (ChR2), which require blue light, enables optical electrophysiology in neurons. The high speed, sensitivity, photostability and long-wavelength fluorescence profiles of BeRST 1 make it a useful platform for the noninvasive, optical dissection of neuronal activity.

The risk factors for elderly patients with bipolar disorder having cerebral infarction.

OBJECTIVE: Patients with bipolar disorder are at high risk of developing strokes in the older life. Silent cerebral infarctions (SCIs) could be common in the elderly patients with bipolar disorder, but only small sample size reports are available. The purpose of this study was to assess the proportion of SCIs and determine the risk factors for cerebral infarction in elderly patients with bipolar disorder. METHODS: We recruited 43 patients with bipolar disorder over the age of 60 to undergo whole-brain magnetic resonance imaging (MRI). We divided them into 2 groups depending on whether infarction was present, and compared the potential variables of these 2 groups. RESULTS: There were 28 elderly patients with bipolar disorder (65.1%) having MRI-proven cerebral infarction. The SCIs were detected in 59.5% (N = 22) of 37 patients without a history of stroke, including 61.3% of 13 patients with late-onset age (>50 years) and 46.7% of 30 patients with typical-onset age (<50 years). Logistic regression revealed that comorbidity with metabolic diseases (95% confidence interval [CI] for odds ratio [OR] = 1.24-40.59) was most strongly associated with cerebral infarction. The leukocyte counts (95% CI for OR = 1.10-3.93) and fasting blood sugar (95% CI for OR = 1.00-1.07) during the most recent acute psychiatric admission may be substituted as the risk factors. CONCLUSIONS: Cerebral infarctions tend to be neglected in more than half of the elderly patients with bipolar disorder, regardless of their age at onset. Metabolic abnormality and systemic inflammation may be the risk factors.

Guanxinping Tablets Inhibit ET-1-Induced Proliferation and Migration of MOVAS by Suppressing Activated PI3K/Akt/NF-κB Signaling Cascade.

Background/Aim: Abnormal proliferation and migration of vascular smooth muscle cells is one of the main causes of atherosclerosis (AS). Therefore, the suppression of abnormal proliferation and migration of smooth muscle cells are the important means for the prevention and inhibition of AS. The clinical effects of Guanxinping (GXP) tablets and preliminary clinical research on the topic have proved that GXP can effectively treat coronary heart disease, but its underlying mechanism remains unclear. This study aimed to confirm the inhibitory effect of GXP on the abnormal proliferation of mouse aortic vascular smooth muscle (MOVAS) cells and to explore the underlying mechanism. Methods: MOVAS cells were divided into two major groups: physiological and pathological groups. In the physiological group, MOVAS cells were directly stimulated with GXP, whereas in the pathological group, the cells were stimulated by endothelin-1 (ET-1) before intervention by GXP. At the same time, atorvastatin calcium, which effectively inhibits the abnormal proliferation of MOVAS cells, was used in the negative control group. CCK8 assay, scratch test, ELISA, Western blotting, and immunofluorescence staining were performed to observe the proliferation and migration of MOVAS cells and the expression levels of related factors after drug intervention in each group. Results: In the physiological group, GXP had no significant effect on the proliferation and migration of MOVAS cells and the related factors. In the pathological group, a high dose of GXP reduced the abnormal proliferation and migration of MOVAS cells. Further, it reduced the expression levels of PI3K; inhibited the phosphorylation of Akt (protein kinase B); upregulated IκB-α levels; prevented nuclear factor kappa B (NF-κB) from entering the nucleus; downregulated the expression of interleukin 6 (IL6), IL-1ß, and iNOS; and upregulated the ratio of apoptosis-related factor Bax/Bcl-2. There was no significant difference between the high-dose GXP group and the atorvastatin calcium group (negative control group). Conclusion: Our findings revealed that GXP was able to inhibit the proliferation and migration of MOVAS cells by regulating the PI3K/Akt/NF-κB pathway.

Volumetric reduction in various cortical regions of elderly patients with early-onset and late-onset mania.

BACKGROUND: Few studies have examined alterations of the brain in elderly bipolar patients. As late-onset mania is associated with increased cerebrovascular morbidity and neurological damage compared with typical/early-onset mania, we investigated differences in the volume of various cortical regions between elderly patients with early-onset versus late-onset mania. METHODS: We recruited 44 bipolar patients aged over 60 years, who underwent volumetric magnetic resonance imaging at 1.5 T. The analytic method is based on the hidden Markov random field model with an expectation-maximization algorithm. We determined the volume of each cortical region as a percentage of the total intracranial volume. The cutoff age for defining early versus late onset was 45 years. RESULTS: The study participants consisted of 25 patients with early-onset mania and 19 patients with late-onset mania; their mean ages were 65.7 years and 62.8 years, respectively. The demographic variables of the two groups were comparable. The volumes of the left caudate nucleus (p = 0.022) and left middle frontal gyrus (p = 0.013) were significantly greater and that of the right posterior cingulate gyrus (p = 0.019) was significantly smaller in the late-onset group. More patients with late-onset mania had comorbid cerebrovascular disease (p = 0.072). CONCLUSIONS: The right posterior cingulate gyrus is smaller and the left caudate nucleus and left middle frontal gyrus are larger in patients with late-onset mania compared with those with early-onset mania. Volumetric change in brain regions may vary in elderly bipolar patients with early and late-onset mania.

Superconductivity in the PbO-type structure alpha-FeSe.

The recent discovery of superconductivity with relatively high transition temperature (Tc) in the layered iron-based quaternary oxypnictides La[O(1-x)F(x)] FeAs by Kamihara et al. [Kamihara Y, Watanabe T, Hirano M, Hosono H (2008) Iron-based layered superconductor La[O1-xFx] FeAs (x = 0.05-0.12) with Tc = 26 K. J Am Chem Soc 130:3296-3297.] was a real surprise and has generated tremendous interest. Although superconductivity exists in alloy that contains the element Fe, LaOMPn (with M = Fe, Ni; and Pn = P and As) is the first system where Fe plays the key role to the occurrence of superconductivity. LaOMPn has a layered crystal structure with an Fe-based plane. It is quite natural to search whether there exists other Fe based planar compounds that exhibit superconductivity. Here, we report the observation of superconductivity with zero-resistance transition temperature at 8 K in the PbO-type alpha-FeSe compound. A key observation is that the clean superconducting phase exists only in those samples prepared with intentional Se deficiency. FeSe, compared with LaOFeAs, is less toxic and much easier to handle. What is truly striking is that this compound has the same, perhaps simpler, planar crystal sublattice as the layered oxypnictides. Therefore, this result provides an opportunity to better understand the underlying mechanism of superconductivity in this class of unconventional superconductors.

Decreased Event-Related Desynchronization of Mental Rotation Tasks in Young Tibetan Immigrants.

The present study aimed to explore the cortical activity underlying mental rotation in high-altitude immigrants via the event-related desynchronization (ERD), the electroencephalogram time-frequency analysis, and source localization based on electroencephalographic data. When compared with the low-altitude individuals, the reaction time of mental rotation tasks was significantly slower in immigrants who had lived in high-altitude areas for 3 years. The time-frequency analysis showed that the alpha ERD and the beta ERD within the time window (400-700 ms) were decreased during the mental rotation tasks in these immigrants. The decreased ERD was observed at the parietal-occipital regions within the alpha band and at the central-parietal regions within the beta band. The decreased ERD might embody the sensorimotor-related cortical activity from hypoxia, which might be involved in cognitive control function in high-altitude immigrants, which provided insights into the neural mechanism of spatial cognition change on aspect of embodied cognition due to high-altitude exposure.

A Redox-Robust Ceramic Anode-Supported Low-Temperature Solid Oxide Fuel Cell.

A critical factor hampering the deployment of fuel-flexible, low-temperature solid oxide fuel cells (LT-SOFCs) is the long-term stability of the electrode in different gas environments. Specifically, for state-of-the-art Ni-cermet anodes, reduction/oxidation (redox) cycles during fuel-rich and fuel-starved conditions cause a huge volume change, eventually leading to cell failure. Here, we report a robust redox-stable SrFe0.2Co0.4Mo0.4O3 (SFCM)/Ce0.9Gd0.1O2 ceramic anode-supported LT-SOFC with high performance and remarkable redox stability. The anode-supported configuration tackles the high ohmic loss associated with conventional ceramic anodes, achieving a high open circuit voltage of ∼0.9 V and a peak power density of 500 mW/cm2 at 600 °C in hydrogen. In addition, ceramic anode-supported SOFCs are stable over tens of redox cycles under harsh operating conditions. Our study reveals that oxygen nonstoichiometry of SFCM compensates for the dimensional changes that occur during redox cycles. Our results demonstrate the potential of all ceramic cells for the next generation of LT-SOFCs.

Potential Control of Oxygen Non-Stoichiometry in Cerium Oxide and Phase Transition Away from Equilibrium.

Cerium oxide (ceria, CeO2) is a technologically important material for energy conversion applications. Its activities strongly depend on redox states and oxygen vacancy concentration. Understanding the functionality of chemical active species and behavior of oxygen vacancy during operation, especially in high-temperature solid-state electrochemical cells, is the key to advance future material design. Herein, the structure evolution of ceria is spatially resolved using bulk-sensitive operando X-ray diffraction and spectroscopy techniques. During water electrolysis, ceria undergoes reduction, and its oxygen non-stoichiometry shows a dependence on the electrochemical current. Cerium local bonding environments vary concurrently to accommodate oxygen vacancy formation, resulting in changes in Ce-O coordination number and Ce3+/Ce4+ redox couple. When reduced enough, a crystallographic phase transition occurs from α to an α' phase with more oxygen vacancies. Nevertheless, the transition behavior is intriguingly different from the one predicted in the standard phase diagram of ceria. This paper demonstrates a feasible means to control oxygen non-stoichiometry in ceria via electrochemical potential. It also sheds light on the mechanism of phase transitions induced by electrochemical potential. For electrochemical systems, effects from a large-scale electrical environment should be taken into consideration, besides effective oxygen partial pressure and temperature.

Novel zinc porphyrin sensitizers for dye-sensitized solar cells: synthesis and spectral, electrochemical, and photovoltaic properties.

Novel meso- or beta-derivatized porphyrins with a carboxyl group have been designed and synthesized for use as sensitizers in dye-sensitized solar cells (DSSCs). The position and nature of a bridge connecting the porphyrin ring and carboxylic acid group show significant influences on the spectral, electrochemical, and photovoltaic properties of these sensitizers. Absorption spectra of porphyrins with a phenylethynyl bridge show that both Soret and Q bands are red-shifted with respect to those of porphyrin 6. This phenomenon is more pronounced for porphyrins 3 and 4, which have a pi-conjugated electron-donating group at the meso position opposite the anchoring group. Upon introduction of an ethynylene group at the meso position, the potential at the first oxidation alters only slightly whereas that for the first reduction is significantly shifted to the positive, thus indicating a decreased HOMO-LUMO gap. Quantum-chemical (DFT) results support the spectroelectrochemical data for a delocalization of charge between the porphyrin ring and the amino group in the first oxidative state of diarylamino-substituted porphyrin 5, which exhibits the best photovoltaic performance among all the porphyrins under investigation. From a comparison of the cell performance based on the same TiO(2) films, the devices made of porphyrin 5 coadsorbed with chenodeoxycholic acid (CDCA) on TiO(2) in ratios [5]/[CDCA] = 1:1 and 1:2 have efficiencies of power conversion similar to that of an N3-based DSSC, which makes this green dye a promising candidate for colorful DSSC applications.

Cognitive dysfunction and medical morbidity in elderly outpatients with bipolar disorder.

OBJECTIVE: The authors investigated the differences in cognitive function, medical burden, and sociodemographic characteristics between elderly community-dwelling bipolar patients and age-matched and education-matched normal individuals. DESIGN: Case-control study. SETTING: Taipei Medical University Hospital, with 75 psychiatric beds, and Taipei City Psychiatric Center-a 612-bed psychiatric teaching hospital providing comprehensive psychiatric services. PARTICIPANTS: Eighty-two euthymic outpatients with bipolar I disorder aged older than 60 years received assessment for research purpose, 59 of whom were matched with one normal control for age and years of education. MEASUREMENTS: All subjects had measurements of cognitive function (Clock-drawing test and Mini-Mental State Examination [MMSE]). Medical morbidity and health condition were according to the medical records, results of free annual elderly health examination, and physical examination on research interviewing. RESULTS: Elderly bipolar patients were found to be more likely than the comparison group to have diabetes mellitus (27.1%), atopic diseases (20.3%), abnormal education-adjusted MMSE scores (32.2%), smoking habit (23.7%), and unfavorable social functioning (22%). Despite having noticeably higher heart rates, the bipolar patients' mean systolic blood pressure and prevalence of hypertension (44.1%) were significantly lower than those of the comparison group. CONCLUSIONS: Although community-dwelling elderly patients with bipolar disorder seem to be characterized by a greater likelihood of developing cognitive dysfunction and concurrent diabetes mellitus, there is no apparent increase in the morbidity of circulatory diseases, particularly less hypertension among those without previous dementia.

Improved Surface Functionalization and Characterization of Membrane-Targeted Semiconductor Voltage Nanosensors.

Type-II ZnSe/CdS voltage-sensing seeded nanorods (vsNRs) were functionalized with α-helical peptides and zwitterionic-decorated lipoic acids (zw-LAs). Specific membrane targeting with high loading efficiency and minimal nonspecific binding was achieved. These vsNRs display quantum yield (QY) modulation as a function of membrane potential (MP) changes, as demonstrated at the ensemble level for (i) vesicles treated with valinomycin and (ii) wild-type HEK cells under alternating buffers with different [K+]. ΔF/F of ∼ 1% was achieved.

Extended metal-atom chains with an inert second row transition metal: [Ru5(mu5-tpda)4X2] (tpda2- = tripyridyldiamido dianion, X = Cl and NCS).

EMACs (extended metal-atom chains) offer a unique platform for the exploration of metal-metal interactions. There has been significant advances on the synthesis of EMACs, such as lengthening the chains up to 11 metal atoms thus far, integrating naphthyridine moieties for tuning the charge carried at metal centers, and manipulation of metal-metal interactions. However, the metal centers in EMACs hitherto are limited to first row transition metals which are more labile than those relatively inert ones with electrons filled in the 4d and 5d shells. In this Communication, the synthesis, crystallographic, magnetic, and electrical conducting studies of [Ru5(mu5-tpda)4Cl2] and [Ru5(mu5-tpda)4(NCS)2], the first pentanuclear EMACs of second-row transition metal, are reported.

Haeme oxygenase and nitric oxide synthetase blockade and brain blood flow in sheep exposed to carbon monoxide.

Carbon monoxide (CO) usually does not damage the brain cortex in our in vivo model. To investigate the possible protective role of responsive and regulated changes in blood flow, 24 ewes were randomly assigned in equal numbers to sham-control, CO-control and treatment (haeme oxygenase (HO) and nitric oxide synthetase (NOS) inhibited) groups. Sheep in the second and third groups were then anaesthetised with CO for 2 h. Brain blood flow was measured using Laser Doppler and was increased in CO exposed sheep. The CO-induced anaesthesia was associated with isolated brain white matter damage. In the HO/NOS inhibited sheep, cortical EEG recovery after the anaesthesia was slower and incomplete, and cortical blood flow increased whereas white matter flow decreased. These results confirm our earlier findings that the induction of HO and NOS by CO inhalation is protective, but, suggest a relationship between tissue injury and blood flow that is perhaps partly causal.

Nanointegrated, High-Performing Cobalt-Free Bismuth-Based Composite Cathode for Low-Temperature Solid Oxide Fuel Cells.

Cost-effective cathodes that actively catalyze the oxygen reduction reaction (ORR) are one of the major challenges for the technological advancement of low-temperature solid oxide fuel cells (LT-SOFCs). In particular, cobalt has been an essential element in electrocatalysts for efficiently catalyzing the ORR; nevertheless, the cost, safety, and stability issues of cobalt in cathode materials remain a severe drawback for SOFC development. Here, we demonstrated that by appropriate nanoengineering, we can overcome the inherent electrocatalytic advantages of cobalt-based cathodes to achieve comparable performance with a cobalt-free electrocatalyst on a bismuth-based fast oxygen ion-conducting scaffold that simultaneously enhances the performance and stability of LT-SOFCs. Consequently, the peak power density of the SOFCs reaches 1.2 W/cm2 at 600 °C, highest performance of a cobalt-free-based cathode that has been ever reported. In addition, by the surface-protecting effect of covered nanoelectrocatalysts, the evaporation of highly volatile bismuth is greatly suppressed, resulting in an 80% improvement in performance durability, the best among all reported bismuth-based fuel cells.

Improving microstructural quantification in FIB/SEM nanotomography.

FIB/SEM nanotomography (FIB-nt) is a powerful technique for the determination and quantification of the three-dimensional microstructure in subsurface features. Often times, the microstructure of a sample is the ultimate determiner of the overall performance of a system, and a detailed understanding of its properties is crucial in advancing the materials engineering of a resulting device. While the FIB-nt technique has developed significantly in the 15 years since its introduction, advanced nanotomographic analysis is still far from routine, and a number of challenges remain in data acquisition and post-processing. In this work, we present a number of techniques to improve the quality of the acquired data, together with easy-to-implement methods to obtain "advanced" microstructural quantifications. The techniques are applied to a solid oxide fuel cell cathode of interest to the electrochemistry community, but the methodologies are easily adaptable to a wide range of material systems. Finally, results from an analyzed sample are presented as a practical example of how these techniques can be implemented.