The escape of heavy ions from the Earth atmosphere is a consequence of energization and transport mechanisms, including photoionization, electron precipitation, ion‐electron‐neutral chemistry, and ...collisions. Numerous studies considered the outflow of O+ ions only, but ignored the observational record of outflowing N+. In spite of 12% mass difference, N+ and O+ ions have different ionization potentials, ionospheric chemistry, and scale heights. We expanded the Polar Wind Outflow Model (PWOM) to include N+ and key molecular ions in the polar wind. We refer to this model expansion as the Seven Ion Polar Wind Outflow Model (7iPWOM), which involves expanded schemes for suprathermal electron production and ion‐electron‐neutral chemistry and collisions. Numerical experiments, designed to probe the influence of season, as well as that of solar conditions, suggest that N+ is a significant ion species in the polar ionosphere and its presence largely improves the polar wind solution, as compared to observations.
Plain Language Summary
Nitrogen is the most abundant element in the Earth's atmosphere. Around 78% N2 and 21% O2 form the air we breathe and expand into high‐altitude atmosphere, the thermosphere, and eventually the ionosphere. The neutral molecules in the ionosphere are ionized by solar radiation, and some of them break up into atoms, and others become charged particles. The ionospheric ions with sufficient energy can flow out into space, and the abundances of these outflowing ionospheric ions highly impact the near‐Earth plasma properties. Studies focused on outflowing O+ ions have been conducted for several years. However, the contribution of N+ ions to the outflow solution is still largely unknown due to the instrumental limitations. This letter addresses the transport and energization of ionospheric N+ ions based on theoretical predictions, and examines the role of N+ ions to the collision and chemistry in the topside ionosphere. This study shows that N+ ions are important components in the high‐altitude polar ionosphere and their abundances can be affected by the sunlight and seasonal variations.
Key Points
We developed a seven‐ion polar wind model (7iPWOM), which solves for the outflowing N+ ions
N+ ions are the second most abundant ionospheric species, up to 1,200 km
The presence of N+ ions improves the overall polar wind solution, when compared with observations
Schizophrenia is a highly debilitating mental disorder that affects approximately 1% of the general population, yet it continues to be poorly understood. Recent studies have identified variations in ...several genes that are associated with this disorder in diverse populations, including those that encode neuregulin 1 (NRG1) and its receptor ErbB4. The past few years have witnessed exciting progress in our knowledge of NRG1 and ErbB4 functions and the biological basis of the increased risk for schizophrenia that is potentially conferred by polymorphisms in the two genes. An improved understanding of the mechanisms by which altered function of NRG1 and ErbB4 contributes to schizophrenia might eventually lead to the development of more effective therapeutics.
As a mussel-inspired material, polydopamine (PDA), possesses many properties, such as a simple preparation process, good biocompatibility, strong adhesive property, easy functionalization, ...outstanding photothermal conversion efficiency, and strong quenching effect. PDA has attracted increasingly considerable attention because it provides a simple and versatile approach to functionalize material surfaces for obtaining a variety of multifunctional nanomaterials. In this review, recent significant research developments of PDA including its synthesis and polymerization mechanism, physicochemical properties, different nano/microstructures, and diverse applications are summarized and discussed. For the sections of its applications in surface modification and biomedicine, we mainly highlight the achievements in the past few years (2016–2019). The remaining challenges and future perspectives of PDA-based nanoplatforms are discussed rationally at the end. This timely and overall review should be desirable for a wide range of scientists and facilitate further development of surface coating methods and the production of PDA-based materials.
Cognitive appraisal theories of emotions suggest that emotions are elicited by evaluations of events and situations and that our beliefs influence the ways we appraise or judge situations that we ...encounter. Gross and John (2003) theorized cognitive reappraisal and expressive suppression as two general forms to regulate emotions. Although teacher emotion has been studied more extensively in the recent decade, Chang (2009b) has argued that there is a need for research into the ways that teachers' implicit beliefs and cognitive processes influence their emotional reactions to the sources of burnout. Particularly, how emotional display rules serve as underlying principles that guide teachers to make decisions either consciously or unconsciously to express or not to express emotions. This study aims to examine the relationships among teachers' beliefs about emotional display rules in the classroom, and the approaches in emotion regulation, and the subsequent feelings of burnout. Survey data was collected from 561 full-time teachers and subjected to hypothesis testing using structural equation modeling. The model provides evidence supporting a pathway between emotion display rules and expressive suppression. These display rules are particularly influential to expressive suppression which also leads to all three dimensions of burnout: emotional exhaustion, depersonalization, and reduced personal accomplishment. Further, uses of cognitive reappraisals are found negatively associated with teacher burnout in all three dimensions. Results of the study indicated that teacher education or profession development should be designed to help teachers to detect and reframe their beliefs about display rules and to engage in cognitive reappraisal so that they may effectively manage their day-to-day emotions in the classroom.
Mitochondria are cellular power plants that supply ATP to power various biological activities essential for neuronal growth, survival, and function. Due to unique morphological features, neurons face ...exceptional challenges to maintain ATP and Ca2+ homeostasis. Neurons require specialized mechanisms distributing mitochondria to distal areas where energy and Ca2+ buffering are in high demand, such as synapses and axonal branches. These distal compartments also undergo development- and activity-dependent remodeling, thereby altering mitochondrial trafficking and distribution. Mitochondria move bi-directionally, pause briefly, and move again, frequently changing direction. In mature neurons, only one-third of axonal mitochondria are motile. Stationary mitochondria serve as local energy sources and buffer intracellular Ca2+. The balance between motile and stationary mitochondria responds quickly to changes in axonal and synaptic physiology. Furthermore, neurons are postmitotic cells surviving for the lifetime of the organism; thus, mitochondria need to be removed when they become aged or dysfunction. Mitochondria also alter their motility under stress conditions or when their integrity is impaired. Therefore, regulation of mitochondrial transport is essential to meet altered metabolic requirements and to remove aged and damaged mitochondria or replenish healthy ones to distal terminals. Defects in mitochondrial transport and altered distribution are implicated in the pathogenesis of several major neurological disorders. Thus, research into the mechanisms regulating mitochondrial motility is an important emerging frontier in neurobiology. This short review provides an updated overview on motor-adaptor machineries that drive and regulate mitochondrial transport and docking receptors that anchor axonal mitochondria in response to the changes in synaptic activity, metabolic requirement, and altered mitochondrial integrity. The review focuses on microtubule (MT)-based mitochondrial trafficking and anchoring. Additional insight from different perspectives can be found in other in-depth reviews.
Nanostructured materials have shown extraordinary promise for electrochemical energy storage but are usually limited to electrodes with rather low mass loading (~1 milligram per square centimeter) ...because of the increasing ion diffusion limitations in thicker electrodes. We report the design of a three-dimensional (3D) holey-graphene/niobia (Nb₂O₅) composite for ultrahigh-rate energy storage at practical levels of mass loading (>10 milligrams per square centimeter). The highly interconnected graphene network in the 3D architecture provides excellent electron transport properties, and its hierarchical porous structure facilitates rapid ion transport. By systematically tailoring the porosity in the holey graphene backbone, charge transport in the composite architecture is optimized to deliver high areal capacity and high-rate capability at high mass loading, which represents a critical step forward toward practical applications.
In recent years, business English narrative genre research has been characterized by ambiguous concepts, insufficient theoretical basis, and single-genre features, which have weakened the reliability ...of research conclusions. Accordingly, this paper examines the representative genre of business English narrative, “management discussion and analysis report”, and explores its genre characteristics and its mapping relationship with corporate performance. The measurement framework is based on the discourse level, genre level, professional practice level, and professional culture level and builds a textual analysis path. In order to observe the lexico-grammatical features highlighted in the four levels of discourse, this paper designs the linguistic feature extraction process and the keyword information extraction method involved in the process. This paper improves the LDA model by introducing the emotional information factor, and improves the keyword extraction algorithm in the model based on information theory. According to the designed method for extracting linguistic features, the representative genre text is analyzed in terms of intonation. Through empirical analysis, it is found that the positive tone and negative tone of the retrospective part of the text of the representative genre are correlated with the current year’s performance of the enterprise at a significant level of 1%, and the positive tone is positively correlated with the current year’s performance, while the negative tone is negatively correlated with the current year’s performance. The positive and negative tone of the outlook texts is not significantly related to the performance of enterprises in the next year. The association of genre characteristics with the current year’s performance of the enterprise is evident but not with the next year’s performance. This paper’s text analysis path can be explored in detail for business English narrative discourse genre measures.
Multifunctional nanomaterials with efficient tumor‐targeting and high antitumor activity are highly anticipated in the field of cancer therapy. In this work, a synergetic tumor‐targeted, ...chemo‐photothermal combined therapeutic nanoplatform based on a dynamically PEGylated, borate‐coordination‐polymer‐coated polydopamine nanoparticle (PDA@CP‐PEG) is developed. PEGylation on the multifunctional nanoparticles is dynamically achieved via the reversible covalent interaction between the surface phenylboronic acid (PBA) group and a catechol‐containing poly(ethylene glycol) (PEG) molecule. Due to the acid‐labile PBA/catechol complex and the weak‐acid‐stable PBA/sialic acid (SA) complex, the nanoparticles can exhibit a synergetic targeting property for the SA‐overexpressed tumor cells, i.e., the PEG‐caused “passive targeting” and PBA‐triggered “active targeting” under the weakly acidic tumor microenvironment. In addition, the photothermal effect of the polydopamine core and the doxorubicin‐loading capacity of the porous coordination polymer layer endow the nanoparticles with the potential for chemo‐photothermal combination therapy. As expected, the in vitro and in vivo studies both verify that the multifunctional nanoparticles possess relatively lower systematic toxicity, efficient tumor targeting ability, and excellent chemo‐photothermal activity for tumor inhibition. It is believed that these multifunctional nanoparticles with synergetic tumor targeting property and combined therapeutic strategies would provide an insight into the design of a high‐efficiency antitumor nanoplatform for potential clinical applications.
Double‐insurance: A synergetic tumor targeted and chemo‐photothermal cancer therapeutic nanoplatform based on dynamically PEGylated and borate‐coordination‐polymer‐coated polydopamine nanoparticles is demonstrated here. The combination of PEGylation‐caused “passive targeting” and phenylboronic acid‐triggered “active targeting” endow the antitumor nanoplatform with low systematic toxicity, efficient tumor targeting, and excellent antitumor activity in vivo.
Eucalyptus bridgesiana, Cymbopogon martinii, Thymus vulgaris, Lindernia anagallis, and Pelargonium fragrans are five species of herbs used in Asia. Their essential oils were analyzed by GC-MS, and a ...total of 36 components were detected. The results of our study indicated that, except for the essential oil of P. fragrans, all of the essential oils demonstrated obvious antimicrobial activity against a broad range of microorganisms. The C. martinii essential oil, which is rich in geraniol, was the most effective antimicrobial additive. All of the essential oils demonstrated antioxidant activities on 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, β-carotene/linoleic acid assay, and nitric oxide radical scavenging assay. Furthermore, the T. vulgaris essential oil, which possesses plentiful thymol, exhibited the highest antioxidant activity. For P. acnes-induced secretion of pro-inflammatory cytokines, the essential oils of P. aeruginosa, C. martinii, and T. vulgaris reduced the TNF-α, IL-1β, and IL-8 secretion levels of THP-1 cells.
Ni–Fe bimetallic electrocatalysts are expected to replace existing precious metal catalysts for water splitting and achieve industrial applications due to their high intrinsic activity and low cost. ...However, the mechanism by which Ni and Fe species synergistically enhance catalytic activity remains obscure, which still needs further in‐depth study. In this study, a highly active bi‐functional electrocatalyst of Ni2P/FeP heterostructures is constructed on Fe foam (Ni2P/FeP‐FF), clearly illustrating the effect of Ni on Fe species for oxygen evolution reaction (OER) and revealing the true catalytic active phase for hydrogen evolution reaction (HER). The Ni2P/FeP‐FF only needs overpotentials of 217 and 42 mV to reach 10 mA cm−2 for OER and HER, respectively, exhibiting superior bi‐functional activity for overall water splitting. The Ni can elevate the strength of FeO on Ni2P/FeP‐FF surface and promote the formation of high‐valence FeOOH phase during OER, thus enhancing OER performance. Based on first‐principles calculations and Raman characterizations, the Ni2P/Ni(OH)2 heterojunction evolved from Ni2P/FeP is identified as the real high active phase for HER. This study not only builds a near‐commercial bifunctional electrocatalyst for overall water splitting, but also provides a deep insight for synergistic catalytic mechanism of Ni and Fe species.
This study fabricates a highly efficient electrocatalyst of Ni2P/FeP heterostructures on Fe foam, which only requires overpotentials of 217 and 42 mV to reach 10 mA cm−2 for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. In addition, this work explicitly unveiles the effect of Ni on Fe species for OER and revealed the true catalytic active phase for HER.
PDF
