We performed a gas analysis of TiO2 nanotube (NT)-type integrated gas sensors using a machine learning (ML) algorithm and neural network-based regression. We fabricated a TiO2-NT integrated gas ...sensor with multiple sensing elements with different response characteristics, and we measured the output signals of each sensing element exposed to a gas mixture, where the main components were nitrogen and oxygen gas with a small amount of carbon monoxide. We analyzed the output signals of the sensor elements using the ML technique to predict the concentrations of CO and O2, to which the TiO2-NT gas sensors were sensitive. Sensor output data were collected for seven sets of mixed gas concentrations with different concentrations of each component gas. Four or five of the seven datasets were used as ML training data for the neural network method, and the concentrations of CO and O2 in the remaining three or two datasets were predicted. Consequently, we confirmed that increasing the number of sensor elements significantly improved the prediction accuracy of the gas concentration. When the output signals from 10 sensor elements were used, the gas concentration could be predicted with an accuracy of less than 0.001% for a carbon monoxide concentration of 0.02%. This accuracy was sufficient for practical application.
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•We performed a gas analysis of TiO2 nanotube (NT)-based integrated gas sensors using a machine learning (ML) technique.•We fabricated a TiO2-NT integrated gas sensor with sensing elements with different response characteristics.•We measured the output signals of each sensing element exposed to a four-component gas mixture.•The gas concentration could be predicted with an accuracy of less than 0.001% for a carbon monoxide concentration of 0.02%.•Increasing the number of sensor elements significantly improved the prediction accuracy of the gas concentration.
The response regulator RpaB plays a central role in transcriptional regulation of photosynthesis-related genes in cyanobacteria. RpaB is phosphorylated by its cognate histidine kinase Hik33 and ...functions as both an activator and repressor under low-light conditions, whereas its phosphorylation level and DNA binding activity promptly decrease upon the upshift of photon flux density, causing changes in gene expression profile. In this study, we assessed the possibility of redox regulation of DNA binding activity of RpaB in Synechocystis sp. PCC 6803 by the addition of inhibitors of photosynthetic electron transport, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), or the reducing agent dithiothreitol (DTT) under different photon flux densities. Analysis of phosphorylation level by phos-tag SDS-PAGE revealed that reduction of QA and increase in the availability of reducing equivalents at the acceptor side of PSI can independently trigger dephosphorylation of RpaB. Nevertheless, chromatin affinity purification revealed that dephosphorylation of RpaB did not cause decrease in its DNA binding activity when the acceptor side of PSI is in oxidized state. The redox state-dependent regulation by an unidentified thiol other than Cys59 of RpaB is prerequisite for phosphorylation-dependent regulation of DNA binding activity. Environmental signals recognized by Hik33 and metabolic signals recognized as the availability of reducing equivalents must be integrated at the master regulator RpaB, attaining the flexible regulation of acclimatory responses.
The stiffness of carbon fiber reinforced polymer (CFRP) composites under alternating bending has been measured as a function of the number of loading cycles at various temperatures and deflection ...amplitudes. The stiffness of the specimens decreases gradually with an increase in the number of loading cycles. Such a stiffness degradation is closely correlated with the residual strength degradation, which suggests that the stiffness degradation process corresponds to the accumulation of microscopic damages under alternating bending. The stiffness degradation rate increases with an increase in temperature and deflection amplitude. By means of the method of reduced variables, a master curve for stiffness degradation that makes it possible to estimate the fatigue life has been composed from the stiffness degradation curves at various temperatures and loading stress levels. The activation energy and activation volume for the elementary process of the stiffness degradation are estimated to be 26 ± 3 kcal/mol and 1.1 × 10−28 m3, respectively. A molecular process for the stiffness degradation is discussed on the basis of the thermally activated process theory.
In this paper, a new procedure is presented which allows the estimation of the states and parameters of the hemodynamic approach from blood oxygenation level dependent (BOLD) responses. The proposed ...method constitutes an alternative to the recently proposed Friston Neuroimage 16 (2002) 513 method and has some advantages over it. The procedure is based on recent groundbreaking time series analysis techniques that have been, in this case, adopted to characterize hemodynamic responses in functional magnetic resonance imaging (fMRI). This work represents a fundamental improvement over existing approaches to system identification using nonlinear hemodynamic models and is important for three reasons. First, our model includes physiological noise. Previous models have been based upon ordinary differential equations that only allow for noise or error to enter at the level of observation. Secondly, by using the innovation method and the local linearization filter, not only the parameters, but also the underlying states of the system generating responses can be estimated. These states can include things like a flow-inducing signal triggered by neuronal activation, de-oxyhemoglobine, cerebral blood flow and volume. Finally, radial basis functions have been introduced as a parametric model to represent arbitrary temporal input sequences in the hemodynamic approach, which could be essential to understanding those brain areas indirectly related to the stimulus. Hence, thirdly, by inferring about the radial basis parameters, we are able to perform a
blind deconvolution, which permits both the reconstruction of the dynamics of the most likely hemodynamic states and also, to implicitly reconstruct the underlying synaptic dynamics, induced experimentally, which caused these states variations. From this study, we conclude that in spite of the utility of the standard discrete convolution approach used in statistical parametric maps (SPM), nonlinear BOLD phenomena and unspecific input temporal sequences must be included in the fMRI analysis.
In this study, we investigated two aspects of verb processing: first, whether verbs are processed differently from nouns; and second, how verbal morphology is processed. For this purpose, we used ...functional magnetic resonance imaging to compare three types of lexical processing in Japanese: the processing of nouns, unmarked active verbs, and inflected passive verbs. Twenty-eight healthy subjects were shown a lexical item and asked to judge whether the presented item was a legal word. Although all three conditions activated the bilateral inferior frontal, occipital, the left middle, and inferior temporal cortices, we found differences in the degree of activation for each condition. Verbs elicited greater activation in the left middle temporal gyrus than nouns, and inflected verbs showed greater activation in the left inferior frontal gyrus than unmarked verbs. This study demonstrates that although verbs are basically processed in the same cortical network as nouns, nouns and verbs elicit different degrees of activation due to the cognitive demands involved in lexical semantic processing. Furthermore, this study also shows that the left inferior frontal cortex is related to the processing of verbal inflectional morphology.
The question of whether the bilingual brain processes a first and second language (L1 and L2, respectively) differently is a central issue in many psycholinguistic and neurolinguistic studies. This ...study used functional magnetic resonance imaging (fMRI) to investigate whether late bilinguals process structurally complex sentences in L1 and L2 in different cortical networks. For this purpose, we directly compared brain activity during the processing of active and passive sentences in both L1 and L2. We asked 36 healthy subjects to judge whether or not a presented sentence was semantically plausible. Both L1 and L2 activated the left hemispheric language-related regions such as the left inferior frontal, superior/middle temporal, and parietal cortices. However, we found different activation patterns between L1 and L2 in the processing of passive sentences. Passive sentences elicited greater activation than their active counterparts in the left pars triangularis, the premotor area, and the superior parietal lobule in Japanese, but not in English. Furthermore, there was a significant interaction between sentence type (active versus passive) and language (Japanese versus English) in the left pars orbitalis. The results of this study indicate that late bilinguals use similar cortical regions to comprehend both L1 and L2. However, when late bilinguals are presented with structurally complex sentences, the involvement of these regions differs between L1 and L2. These results suggest that, in addition to age of L2 acquisition and L2 proficiency, differences in grammatical construction affect cortical representation during the comprehension of L1 and L2.
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Bulk nanobubbles (NBs) have high surface charge densities and long lifetimes. Despite several attempts to understand the lifetime of NBs, their interfacial layer structure remains ...unknown. It is hypothesized that a specific interfacial layer exists with a hydrogen bond network that stabilizes NBs.
In situ infrared reflectance–absorption spectroscopy and density functional theory were used to determine the interfacial layer structure of NBs. Furthermore, nuclear magnetic resonance spectroscopy was used to examine the interfacial layer hardness of bubbles filled with N2, O2, and CO2, which was expected to depend on the encapsulated gas species.
The interfacial layer was composed of three-, four-, and five-membered ring clusters of water molecules. An interface model was proposed in which a two-dimensional layer of clusters with large electric dipole moments is oriented toward the endohedral gas, and the hydrophobic surface is adjacent to the free water. The interfacial layer hardness was dependent on the interaction with the gas (N2 > O2 > CO2), which supports the proposed interface model. These findings can be generalized to the structure of water at gas–water interfaces.
Previously, we experimentally demonstrated that similar-sized bulk nanobubbles (NBs) preferentially coalesce when the NB size is ∼100 nm. To explain this peculiar NB coalescence phenomenon, we ...performed a nanoparticle trajectory analysis to determine the size distribution profile and time-dependent concentration of the bulk NBs generated by pressurizing a porous alumina thin film with ordered straight nanoholes. Furthermore, we propose a physical model based on the hypothesis that the repulsive energy increases when two NBs establish contact, and that coalescence occurs when the kinetic energy of the NBs overcomes the repulsive energy. We simulated the observed NB-size distribution by using the proposed model. The simulation results explained the observed NB-size distribution and lifetime of the NBs. They further indicated that NB coalescence was suppressed for small NBs with diameters of approximately 100 nm or less, resulting in their long lifetimes.
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•Similar-sized bulk nanobubbles (NBs) preferentially coalesce for small NBs.•A physical model was proposed in which the repulsive energy increases when two NBs establish contact.•The simulation based on the model explained the size distribution and lifetime of the NBs.•NB coalescence was suppressed for small NBs, resulting in their long lifetimes.
A dense plasma focus device can produce dense and high energy plasma in a short time. Recently, it has been proposed that the device could be applied to fusion for clean energy production (focus ...fusion). In order to understand the behavior of the plasma current filaments in the device, two-dimensional, relativistic, fully electromagnetic, particle-in-cell simulations were performed. Sixteen plasma current filaments were initially located on the edge of a circle in our model. They begin to interact with each other while pinching, and then coalesce in the vicinity of the center of system. In the pinch phase (during the coalescence), there appears dense plasma, whose maximum number density is 10 times larger than the initial value. The ions are accelerated, but the rate of the number of them is somewhat small. After that, the current becomes unstable and jumps out from the center. These results are useful for understanding the coalescence process of current filaments.
The present study aims to confirm the cortical correlates of scrambling effects, a free word order phenomenon that has been observed in a variety of cross-linguistic investigations but whose ...mechanism still remains unclarified. Many syntax-oriented hypotheses on scrambling have been provided to develop the structural basis of the free word order permutation in Japanese, leading to the most recent phrasal architecture, in which the object noun phrase of a transitive sentence “moves” to a higher position than the subject to form an asymmetric structure including antecedent–gap relationships. Such a configurational structure formed by scrambling operation predicts that the scrambled sentences have a more complex structure than canonical sentences, and that the former requires a greater burden on cognitive processes in related areas within the brain. Based on this general assumption, we employed an experimental method of whole-sentence presentation of Japanese transitive sentences, for both canonical transitive sentences (
Subject–Object–Verb) and their scrambled counterparts (
Object–Subject–Verb). The result showed more activation at the left inferior frontal gyrus (IFG) and the left dorsal prefrontal cortex (DPFC) during the comprehension of scrambled sentences than that of canonical sentences. This indicates, in accordance with previous findings on scrambling from neurolinguistic perspectives, that the scrambling in Japanese is indeed one of the grammatical operations and that the parsing strategy for the asymmetric antecedent–gap relationship demands an additional cognitive activation in the brain.
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