The nonexistence of a paddlewheel effect in superionic conductors.

Since the 1980s, the paddlewheel effect has been suggested as a mechanism to boost lithium-ion diffusion in inorganic materials via the rotation of rotor-like anion groups. However, it remains unclear whether the paddlewheel effect, defined as large-angle anion group rotations assisting Li hopping, indeed exists; furthermore, the physical mechanism by which the anion-group dynamics affect lithium-ion diffusion has not yet been established. In this work, we differentiate various types of rotational motions of anion groups and develop quaternion-based algorithms to detect, quantify, and relate them to lithium-ion motion in ab initio molecular dynamics simulations. Our analysis demonstrates that, in fact, the paddlewheel effect, where an anion group makes a large angle rotation to assist a lithium-ion hop, does not exist and thus is not responsible for the fast lithium-ion diffusion in superionic conductors, as historically claimed. Instead, we find that materials with topologically isolated anion groups can enhance lithium-ion diffusivity via a more classic nondynamic soft-cradle mechanism, where the anion groups tilt to provide optimal coordination to a lithium ion throughout the hopping process to lower the migration barrier. This anion-group disorder is static in nature, rather than dynamic and can explain most of the experimental observations. Our work substantiates the nonexistence of the long-debated paddlewheel effect and clarifies any correlation that may exist between anion-group rotations and fast ionic diffusion in inorganic materials.

Quantitative Topic Analysis of Materials Science Literature Using Natural Language Processing.

Materials science research has garnered extensive attention from industry, society, policy, and academia. However, understanding the research landscape and extracting strategic insights are challenging due to the increasing diversity and volume of publications. This study proposes a natural language processing-based protocol for extracting text-encoded topics from a large volume of scientific literature, uncovering research interests of scientific communities, as well as convergence trends. We report a topic map, representing the materials science research landscape with text-mined 257 topics regarding biocompatible materials, structural materials, electrochemistry, or photonics. We analyze the topic map in terms of national research interests in materials science, revealing competitive positions and strategies of active nations. For example, it is found that the increasing trend of research interest in machine learning topic was captured in the United States earlier than other nations. Similarly, our journal-level analyses serve as reference information for journal recommendations and trend guidance, showing that the main topics and research interests of materials science journals slightly changed over time. Moreover, we build the topic association network which can highlight the status and future potential of interdisciplinary research, revealing research fields with high centrality in the network such as machine learning-enabled composite modeling, energy policy, or wearable electronics. This study offers insightful results on current and near-future materials science research landscapes, facilitating the understanding of stakeholders, amidst the fast-evolving and diverse knowledge of materials science.

Spexin Regulates Hypothalamic Leptin Action on Feeding Behavior.

Spexin (SPX) is a recently identified neuropeptide that is believed to play an important role in the regulation of energy homeostasis. Here, we describe a mediating function of SPX in hypothalamic leptin action. Intracerebroventricular (icv) SPX administration induced a decrease in food intake and body weight gain. SPX was found to be expressed in cells expressing leptin receptor ObRb in the mouse hypothalamus. In line with this finding, icv leptin injection increased SPX mRNA in the ObRb-positive cells of the hypothalamus, which was blocked by treatment with a STAT3 inhibitor. Leptin also increased STAT3 binding to the SPX promoter, as measured by chromatin immunoprecipitation assays. In vivo blockade of hypothalamic SPX biosynthesis with an antisense oligodeoxynucleotide (AS ODN) resulted in a diminished leptin effect on food intake and body weight. AS ODN reversed leptin's effect on the proopiomelanocortin (POMC) mRNA expression and, moreover, decreased leptin-induced STAT3 binding to the POMC promoter sequence. These results suggest that SPX is involved in leptin's action on POMC gene expression in the hypothalamus and impacts the anorexigenic effects of leptin.

Cognitive trajectories of patients with focal ß-amyloid deposition.

BACKGROUND: The presence of ß-amyloid (Aß) in the brain can be identified using amyloid PET. In clinical practice, the amyloid PET is interpreted based on dichotomous visual rating, which renders focal Aß accumulation be read as positive for Aß. However, the prognosis of patients with focal Aß deposition is not well established. Thus, we investigated cognitive trajectories of patients with focal Aß deposition. METHODS: We followed up 240 participants (112 cognitively unimpaired [CU], 78 amnestic mild cognitive impairment [aMCI], and 50 Alzheimer's disease (AD) dementia [ADD]) for 2 years from 9 referral centers in South Korea. Participants were assessed with neuropsychological tests and 18F-flutemetamol (FMM) positron emission tomography (PET). Ten regions (frontal, precuneus/posterior cingulate (PPC), lateral temporal, parietal, and striatum of each hemisphere) were visually examined in the FMM scan, and participants were divided into three groups: No-FMM, Focal-FMM (FMM uptake in 1-9 regions), and Diffuse-FMM. We used mixed-effects model to investigate the speed of cognitive decline in the Focal-FMM group according to the cognitive level, extent, and location of Aß involvement, in comparison with the No- or Diffuse-FMM group. RESULTS: Forty-five of 240 (18.8%) individuals were categorized as Focal-FMM. The rate of cognitive decline in the Focal-FMM group was faster than the No-FMM group (especially in the CU and aMCI stage) and slower than the Diffuse-FMM group (in particular in the CU stage). Within the Focal-FMM group, participants with FMM uptake to a larger extent (7-9 regions) showed faster cognitive decline compared to those with uptake to a smaller extent (1-3 or 4-6 regions). The Focal-FMM group was found to have faster cognitive decline in comparison with the No-FMM when there was uptake in the PPC, striatum, and frontal cortex. CONCLUSIONS: When predicting cognitive decline of patients with focal Aß deposition, the patients' cognitive level, extent, and location of the focal involvement are important.

Concordance in detecting amyloid positivity between 18F-florbetaben and 18F-flutemetamol amyloid PET using quantitative and qualitative assessments.

We aimed to quantitatively and qualitatively assess whether there is a discrepancy in detecting amyloid beta (Aß) positivity between 18F-florbetaben (FBB) and 18F-flutemetamol (FMM) positron emission tomography (PET). We obtained paired FBB and FMM PET images from 107 participants. Three experts visually quantified the Aß deposition as positive or negative. Quantitative assessment was performed using global cortical standardized uptake value ratio (SUVR) with the whole cerebellum as the reference region. Inter-rater agreement was excellent for FBB and FMM. The concordance rates between FBB and FMM were 94.4% (101/107) for visual assessment and 98.1% (105/107) for SUVR cut-off categorization. Both FBB and FMM showed high agreement rates between visual assessment and SUVR positive or negative categorization (93.5% in FBB and 91.2% in FMM). When the two ligands were compared based on SUVR cut-off categorization as standard of truth, although not statistically significant, the false-positive rate was higher in FMM (9.1%) than in FBB (1.8%) (p = 0.13). Our findings suggested that both FBB and FMM had excellent agreement when used to quantitatively and qualitatively evaluate Aß deposits, thus, combining amyloid PET data associated with the use of different ligands from multi-centers is feasible.

Clinical significance of focal ß-amyloid deposition measured by 18F-flutemetamol PET.

BACKGROUND: Although amyloid PET of typical Alzheimer's disease (AD) shows diffuse ß-amyloid (Aß) deposition, some patients show focal deposition. The clinical significance of this focal Aß is not well understood. We examined the clinical significance of focal Aß deposition in terms of cognition as well as Aß and tau cerebrospinal fluid (CSF) levels. We further evaluated the order of Aß accumulation by visual assessment. METHODS: We included 310 subjects (125 cognitively unimpaired, 125 mild cognitive impairment, and 60 AD dementia) from 9 referral centers. All patients underwent neuropsychological tests and 18F-flutemetamol (FMM) PET. Seventy-seven patients underwent CSF analysis. Each FMM scan was visually assessed in 10 regions (frontal, precuneus and posterior cingulate, lateral temporal, parietal, and striatum of each hemisphere) and was classified into three groups: No-FMM, Focal-FMM (FMM uptake in 1-9 regions), and Diffuse-FMM (FMM uptake in all 10 regions). RESULTS: 53/310 (17.1%) subjects were classified as Focal-FMM. The cognitive level of the Focal-FMM group was better than that of Diffuse-FMM group and worse than that of No-FMM group. Among the Focal-FMM group, those who had FMM uptake to a larger extent or in the striatum had worse cognitive levels. Compared to the Diffuse-FMM group, the Focal-FMM group had a less AD-like CSF profile (increased Aß42 and decreased t-tau, t-tau/Aß42). Among the Focal-FMM group, Aß deposition was most frequently observed in the frontal (62.3%) and least frequently observed in the striatum (43.4%) and temporal (39.6%) regions. CONCLUSIONS: We suggest that focal Aß deposition is an intermediate stage between no Aß and diffuse Aß deposition. Furthermore, among patients with focal Aß deposition, those who have Aß to a larger extent and striatal involvement show clinical features close to diffuse Aß deposition. Further longitudinal studies are needed to evaluate the disease progression of patients with focal Aß deposition.

Predicting the chemical reactivity of organic materials using a machine-learning approach.

Stability and compatibility between chemical components are essential parameters that need to be considered in the selection of functional materials in configuring a system. In configuring devices such as batteries or solar cells, not only the functionality of individual constituting materials such as electrodes or electrolyte but also an appropriate combination of materials which do not undergo unwanted side reactions is critical in ensuring their reliable performance in long-term operation. While the universal theory that can predict the general chemical reactivity between materials is long awaited and has been the subject of studies with a rich history, traditional ways proposed to date have been mostly based on simple electronic properties of materials such as electronegativity, ionization energy, electron affinity and hardness/softness, and could be applied to only a small group of materials. Moreover, prediction has often been far from accurate and has failed to offer general implications; thus it was practically inadequate as a selection criterion from a large material database, i.e. data-driven material discovery. Herein, we propose a new model for predicting the general reactivity and chemical compatibility among a large number of organic materials, realized by a machine-learning approach. As a showcase, we demonstrate that our new implemented model successfully reproduces previous experimental results reported on side-reactions occurring in lithium-oxygen electrochemical cells. Furthermore, the mapping of chemical stability among more than 90 available electrolyte solvents and the representative redox mediators is realized by this approach, presenting an important guideline in the development of stable electrolyte/redox mediator couples for lithium-oxygen batteries.

Sex-specific relationship of cardiometabolic syndrome with lower cortical thickness.

OBJECTIVE: To investigate whether cardiometabolic factors were associated with age-related differences in cortical thickness in relation to sex. METHODS: In this cross-sectional study, we enrolled 1,322 cognitively normal elderly (≥65 years old) individuals (774 [58.5%] men, 548 [41.5%] women). We measured cortical thickness using a surface-based analysis. We analyzed the associations of cardiometabolic risk factors with cortical thickness using multivariate linear regression models after adjusting for possible confounders and interactions with age. RESULT: Among women, hypertension (ß = -1.119 to -0.024, p < 0.05) and diabetes mellitus (ß = -0.920, p = 0.03) were independently associated with lower mean cortical thickness. In addition, there was an interaction effect between obesity (body mass index [BMI] ≥27.5 kg/m2) and age on cortical thickness in women (ß = -0.324 to -0.010, p < 0.05), suggesting that age-related differences in cortical thickness were more prominent in obese women compared to women with normal weight. Moreover, low education level (<6 years) was correlated with lower mean cortical thickness (ß = -0.053 to -0.046, p < 0.05). Conversely, among men, only being underweight (BMI ≤18.5 kg/m2, ß = -2.656 to -0.073, p < 0.05) was associated with lower cortical thickness. CONCLUSIONS: Our findings suggest that cortical thickness is more vulnerable to cardiometabolic risk factors in women than in men. Therefore, sex-specific prevention strategies may be needed to protect against accelerated brain aging.

Reliable autapse formation using the single-cell patterning method.

Auto neuronal synapses, or autapses, are aberrant structures where the synaptic contact of a neuron forms onto its own branch. The functions of autapses, however, remain unknown. Here, we introduce a simple patterning method for capturing a single-cell, in which we maintained the isolated cell until it reached maturity, and developed arrays of autapses for electrophysiological analysis using multi-electrode arrays (MEA). The pattern arrays were formed by selective patterning of poly-L-lysine and various cell repellent materials. We tested the efficiency of single neuron pattern formed according to materials and pattern dimensions. Autapse formation was verified by immunostaining synaptic markers and physiological measurements via recordings from MEA. The results demonstrated that our multiscale patterning method increased the number of autapses consisting of a single neuron, which matured to connect onto themselves. The proposed patterning method (4.06 ± 0.33 isolated single-cells mm-2) is at least twelve times more efficient and productive than the spray method (0.31 ± 0.10 isolated single-cells mm-2). The spontaneous activity of a single neuron on the patterned MEA occured after 11 d in vitro. The single neuron activity consisted of bursts followed by spike trains (the burst rate was 2.56 min-1). This indicates that our method could be used for electrophysiological analysis, including MEA.

High-efficiency and high-power rechargeable lithium-sulfur dioxide batteries exploiting conventional carbonate-based electrolytes.

Shedding new light on conventional batteries sometimes inspires a chemistry adoptable for rechargeable batteries. Recently, the primary lithium-sulfur dioxide battery, which offers a high energy density and long shelf-life, is successfully renewed as a promising rechargeable system exhibiting small polarization and good reversibility. Here, we demonstrate for the first time that reversible operation of the lithium-sulfur dioxide battery is also possible by exploiting conventional carbonate-based electrolytes. Theoretical and experimental studies reveal that the sulfur dioxide electrochemistry is highly stable in carbonate-based electrolytes, enabling the reversible formation of lithium dithionite. The use of the carbonate-based electrolyte leads to a remarkable enhancement of power and reversibility; furthermore, the optimized lithium-sulfur dioxide battery with catalysts achieves outstanding cycle stability for over 450 cycles with 0.2 V polarization. This study highlights the potential promise of lithium-sulfur dioxide chemistry along with the viability of conventional carbonate-based electrolytes in metal-gas rechargeable systems.

Reaction chemistry in rechargeable Li-O2 batteries.

The seemingly simple reaction of Li-O2 batteries involving lithium and oxygen makes this chemistry attractive for high-energy-density storage systems; however, achieving this reaction in practical rechargeable Li-O2 batteries has proven difficult. The reaction paths leading to the final Li2O2 discharge products can be greatly affected by the operating conditions or environment, which often results in major side reactions. Recent research findings have begun to reveal how the reaction paths may be affected by the surrounding conditions and to uncover the factors contributing to the difficulty in achieving the reactions of lithium and oxygen. This progress report describes the current state of understanding of the electrode reaction mechanisms in Li-O2 batteries; the factors that affect reaction pathways; and the effect of cell components such as solvents, salts, additives, and catalysts on the discharge product and its decomposition during charging. This comprehensive review of the recent progress in understanding the reaction chemistry of the Li-O2 system will serve as guidelines for future research and aid in the development of reliable high-energy-density rechargeable Li-O2 batteries.

Dissolution and ionization of sodium superoxide in sodium-oxygen batteries.

With the demand for high-energy-storage devices, the rechargeable metal-oxygen battery has attracted attention recently. Sodium-oxygen batteries have been regarded as the most promising candidates because of their lower-charge overpotential compared with that of lithium-oxygen system. However, conflicting observations with different discharge products have inhibited the understanding of precise reactions in the battery. Here we demonstrate that the competition between the electrochemical and chemical reactions in sodium-oxygen batteries leads to the dissolution and ionization of sodium superoxide, liberating superoxide anion and triggering the formation of sodium peroxide dihydrate (Na2O2·2H2O). On the formation of Na2O2·2H2O, the charge overpotential of sodium-oxygen cells significantly increases. This verification addresses the origin of conflicting discharge products and overpotentials observed in sodium-oxygen systems. Our proposed model provides guidelines to help direct the reactions in sodium-oxygen batteries to achieve high efficiency and rechargeability.

Synergistic multi-doping effects on the Li7La3Zr2O12 solid electrolyte for fast lithium ion conduction.

Here, we investigate the doping effects on the lithium ion transport behavior in garnet Li7La3Zr2O12 (LLZO) from the combined experimental and theoretical approach. The concentration of Li ion vacancy generated by the inclusion of aliovalent dopants such as Al(3+) plays a key role in stabilizing the cubic LLZO. However, it is found that the site preference of Al in 24d position hinders the three dimensionally connected Li ion movement when heavily doped according to the structural refinement and the DFT calculations. In this report, we demonstrate that the multi-doping using additional Ta dopants into the Al-doped LLZO shifts the most energetically favorable sites of Al in the crystal structure from 24d to 96 h Li site, thereby providing more open space for Li ion transport. As a result of these synergistic effects, the multi-doped LLZO shows about three times higher ionic conductivity of 6.14 × 10(-4) S cm(-1) than that of the singly-doped LLZO with a much less efforts in stabilizing cubic phases in the synthetic condition.

A New Perspective on Li-SO2 Batteries for Rechargeable Systems.

Primary Li-SO2 batteries offer a high energy density in a wide operating temperature range with exceptionally long shelf life and have thus been frequently used in military and aerospace applications. Although these batteries have never been demonstrated as a rechargeable system, herein, we show that the reversible formation of Li2S2O4, the major discharge product of Li-SO2 battery, is possible with a remarkably smaller charging polarization than that of a Li-O2 battery without the use of catalysts. The rechargeable Li-SO2 battery can deliver approximately 5400 mAh g(-1) at 3.1 V, which is slightly higher than the performance of a Li-O2 battery. In addition, the Li-SO2 battery can be operated with the aid of a redox mediator, exhibiting an overall polarization of less than 0.3 V, which results in one of the highest energy efficiencies achieved for Li-gas battery systems.

Ti-substituted tunnel-type Na0.44MnO2 oxide as a negative electrode for aqueous sodium-ion batteries.

The aqueous sodium-ion battery system is a safe and low-cost solution for large-scale energy storage, because of the abundance of sodium and inexpensive aqueous electrolytes. Although several positive electrode materials, for example, Na0.44MnO2, were proposed, few negative electrode materials, for example, activated carbon and NaTi2(PO4)3, are available. Here we show that Ti-substituted Na0.44MnO2 (Na0.44[Mn1-xTix]O2) with tunnel structure can be used as a negative electrode material for aqueous sodium-ion batteries. This material exhibits superior cyclability even without the special treatment of oxygen removal from the aqueous solution. Atomic-scale characterizations based on spherical aberration-corrected electron microscopy and ab initio calculations are utilized to accurately identify the Ti substitution sites and sodium storage mechanism. Ti substitution tunes the charge ordering property and reaction pathway, significantly smoothing the discharge/charge profiles and lowering the storage voltage. Both the fundamental understanding and practical demonstrations suggest that Na0.44[Mn1-xTix]O2 is a promising negative electrode material for aqueous sodium-ion batteries.

Biologically inspired pteridine redox centres for rechargeable batteries.

The use of biologically occurring redox centres holds a great potential in designing sustainable energy storage systems. Yet, to become practically feasible, it is critical to explore optimization strategies of biological redox compounds, along with in-depth studies regarding their underlying energy storage mechanisms. Here we report a molecular simplification strategy to tailor the redox unit of pteridine derivatives, which are essential components of ubiquitous electron transfer proteins in nature. We first apply pteridine systems of alloxazinic structure in lithium/sodium rechargeable batteries and unveil their reversible tautomerism during energy storage. Through the molecular tailoring, the pteridine electrodes can show outstanding performance, delivering 533 Wh kg(-1) within 1 h and 348 Wh kg(-1) within 1 min, as well as high cyclability retaining 96% of the initial capacity after 500 cycles at 10 A g(-1). Our strategy combined with experimental and theoretical studies suggests guidance for the rational design of organic redox centres.

Deficiency for costimulatory receptor 4-1BB protects against obesity-induced inflammation and metabolic disorders.

OBJECTIVE: Inflammation is an important factor in the development of insulin resistance, type 2 diabetes, and fatty liver disease. As a member of the tumor necrosis factor receptor superfamily (TNFRSF9) expressed on immune cells, 4-1BB/CD137 provides a bidirectional inflammatory signal through binding to its ligand 4-1BBL. Both 4-1BB and 4-1BBL have been shown to play an important role in the pathogenesis of various inflammatory diseases. RESEARCH DESIGN AND METHODS: Eight-week-old male 4-1BB-deficient and wild-type (WT) mice were fed a high-fat diet (HFD) or a regular diet for 9 weeks. RESULTS: We demonstrate that 4-1BB deficiency protects against HFD-induced obesity, glucose intolerance, and fatty liver disease. The 4-1BB-deficient mice fed an HFD showed less body weight gain, adiposity, adipose infiltration of macrophages/T cells, and tissue levels of inflammatory cytokines (e.g., TNF-α, interleukin-6, and monocyte chemoattractant protein-1 [MCP-1]) compared with HFD-fed control mice. HFD-induced glucose intolerance/insulin resistance and fatty liver were also markedly attenuated in the 4-1BB-deficient mice. CONCLUSIONS: These findings suggest that 4-1BB and 4-1BBL may be useful therapeutic targets for combating obesity-induced inflammation and metabolic disorders.

Protein kinase C-delta mediates neuronal apoptosis in the retinas of diabetic rats via the Akt signaling pathway.

OBJECTIVE: Protein kinase C (PKC)-delta, an upstream regulator of the Akt survival pathway, contributes to cellular dysfunction in the pathogenesis of diabetes. Herein, we examined the role of PKC-delta in neuronal apoptosis through Akt in the retinas of diabetic rats. RESEARCH DESIGN AND METHODS: We used retinas from 24- and 35-week-old male Otsuka Long-Evans Tokushima fatty (OLETF) diabetic and Long-Evans Tokushima Otsuka (LETO) nondiabetic rats. To assess whether PKC-delta affects Akt signaling and cell death in OLETF rat retinas, we examined 1) PKC-delta activity and apoptosis; 2) protein levels of phosphatidylinositol 3-kinase (PI 3-kinase) p85, heat shock protein 90 (HSP90), and protein phosphatase 2A (PP2A); 3) Akt phosphorylation; and 4) Akt binding to HSP90 or PP2A in LETO and OLETF retinas in the presence or absence of rottlerin, a highly specific PKC-delta inhibitor, or small interfering RNAs (siRNAs) for PKC-delta and HSP90. RESULTS: In OLETF retinas from 35-week-old rats, ganglion cell death, PKC-delta and PP2A activity, and Akt-PP2A binding were significantly increased and Akt phosphorylation and Akt-HSP90 binding were decreased compared with retinas from 24-week-old OLETF and LETO rats. Rottlerin and PKC-delta siRNA abrogated these effects in OLETF retinas from 35-week-old rats. HSP90 siRNA significantly increased ganglion cell death and Akt-PP2A complexes and markedly decreased HSP90-Akt binding and Akt phosphorylation in LETO retinas from 35-week-old rats compared with those from nontreated LETO rats. CONCLUSIONS: PKC-delta activation contributes to neuro-retinal apoptosis in diabetic rats by inhibiting Akt-mediated signaling pathways.