We present a simple strategy for the fabrication of porous carbon nanofibers (see figure). This procedure produces thin webs by electrospinning a polymer solution containing different concentrations ...of zinc chloride and subsequently thermally treating the system. Their resulting surface area and good electrical conductivity make these porous carbon nanofibers useful in the fabrication of efficient electrodes for supercapacitors.
Dimensionality is a critical factor in determining the properties of solids and is an apparent built-in character of the crystal structure. However, it can be an emergent and tunable property in ...geometrically frustrated spin systems. Here, we study the spin dynamics of the tetrahedral cluster antiferromagnet, pharmacosiderite, via muon spin resonance and neutron scattering. We find that the spin correlation exhibits a two-dimensional characteristic despite the isotropic connectivity of tetrahedral clusters made of spin 5/2 Fe
ions in the three-dimensional cubic crystal, which we ascribe to two-dimensionalisation by geometrical frustration based on spin wave calculations. Moreover, we suggest that even one-dimensionalisation occurs in the decoupled layers, generating low-energy and one-dimensional excitation modes, causing large spin fluctuation in the classical spin system. Pharmacosiderite facilitates studying the emergence of low-dimensionality and manipulating anisotropic responses arising from the dimensionality using an external magnetic field.
One of the most characterized neurotrophic factors is brain-derived neurotrophic factor (BDNF), which regulates neuronal survival and differentiation, and functions in activity-dependent plasticity ...processes such as long-term potentiation, long-term depression (LTD), and learning memory. Similar to other growth factors, BDNF protein is produced by transcriptional and translational mechanisms. Nevertheless, a posttranslational mechanism, the proteolytic conversion of precursor BDNF into at least two fragments, bioactive BDNF and the prodomain, has not been well elucidated. Recently, we demonstrated that the BDNF prodomain, which is named the BDNF propeptide, was endogenously secreted from neuronal cells and facilitated a cellular mechanism of LTD, suggesting the manner through which this posttranslational mechanism multiplies the biological actions of BDNF. In this chapter, we focus on the BDNF propeptide, especially in synaptic plasticity, and discuss the role of this molecule in the brain. The findings regarding the BDNF propeptide would provide new insights for understanding the mechanisms of action of the propeptides of growth factors as well as the biological roles of neurotrophins.
There are numerous wooden historical artifacts in Kyoto and other parts of Japan, including Buddhist statues or Shinto deities. The identification of wood species in these historical artifact is ...desirable for both repair and maintenance purposes. The most common method of identifying wood species involves examining samples taken from the artifacts. However, intentional sampling from old cultural artifacts is prohibited in Japan. As a result, we attempted to determine the wood species of old statues non-destructively using near-infrared spectroscopy (NIRS). In this article, we developed the softwood and hardwood separation model using NIRS to compare the prediction accuracy for few algorithms. The model was created based on wood samples stored in the xylarium of the Forestry and Forest Products Research Institute (TWTw). We then applied this model to old Buddhist statues in order to classify them as either softwood or hardwood. These Buddhist statues were housed in Nazenji temple and are believed to have been carved during the Heian period (8th–12th century). For the near-infrared (NIR) measurements, we collected diffuse reflectance spectra from TWTw sample and Buddhist statues using same spectrometer. Initially, we used the soft independent modeling of class analogy method (SIMCA), partial least squares discriminant analysis (PLS_DA), and support vector machine to analyze the NIR spectra obtained from the TWTw wood samples. Subsequently, we applied the NIR spectra obtained from several Buddhist statues in Nazenji temple to the aforementioned separation model and determined whether spectra data were classified as the softwood or hardwood. Finally, wood specimens detached naturally from the Buddhist statues over time were observed under microscopic analysis to identify the wood species. As comparing the prediction accuracy of few algorithms, SIMCA had a poor result, but PLS_DA had a good result. PLS_DA had better discrimination because it performed calculations to improve regression from both explanatory variables and objective variables.
Abstract Background The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more ...complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. Scope of review In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery. Major conclusions In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism.
A carbon nanofiber‐based electrode, exhibiting a large accessible surface area (derived from the nanometer‐sized fiber diameter), high carbon purity (without binder), relatively high electrical ...conductivity, structural integrity, thin web macromorphology, a large reversible capacity (ca. 450 mA h g–1), and a relatively linearly inclined voltage profile, is fabricated by nanofiber formation via electrospinning of a polymer solution and its subsequent thermal treatment. It is envisaged that these characteristics of this novel carbon material will make it an ideal candidate for the anode material of high‐power lithium‐ion batteries (where a high current is critically needed), owing to the highly reduced lithium‐ion diffusion path within the active material.
High‐purity carbon nanofiber webs are fabricated using an electrospinning technique and thermal treatment (see figure). This fibrous carbon possesses properties (e.g., large accessible surface area, good electrical conductivity, high reversible capacity ca. 450 mA h g–1) that make it a potentially excellent candidate for use as the anode material in high‐power lithium‐ion batteries, owing to the highly reduced lithium‐ion diffusion path within the active material.
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