Nara Institute of Science and Technology
Recent publications
1ReH•Cl, a highly robust and antiaromatic rhenium(I) complex of triarylrosarin, is synthesized. The 1H NMR spectrum of 1ReH•Cl shows upfield-shifted pyrrole protons and highly downfield-shifted inner protons that confirm its antiaromatic nature, with density functional theory calculations strongly supporting this interpretation. Antiaromatic 1ReH•Cl absorbs from the UV to near-IR region of the optical spectrum; cyclic voltammetry, thin-layer UV-vis spectroelectrochemistry, and spin-density distributions clearly reveal that the rosarin backbone of 1ReH•Cl undergoes redox chemistry. The X-ray structure of 1ReH•Cl shows a fully coordinated and protonated inner cavity that effectively prevents proton-coupled electron transfer when treated with an acid. A remarkably negative NICS(0) value, clockwise anisotropy of the induced current density ring current, and the aromatic shielded inner cavity in the 2D ICSS(0) map reveal that the T1 state of 1ReH•Cl is aromatic based on Baird's rule.
The peroxidase activity of cytochrome (cyt) c increases when Met80 dissociates from the heme iron, which is related to the initial cyt c membrane permeation step of apoptosis. Met80-dissociated cyt c can form an oxygenated species. Herein, resonance Raman spectra of Met80-depleted horse cyt c (M80A cyt c) were analyzed to elucidate the heme ligand properties of Met80-dissociated cyt c. The Fe-His stretching (νFe-His) mode of ferrous M80A cyt c was observed at 236 cm-1, and this frequency decreased by 1.5 cm-1 for the 15N-labeled protein. The higher νFe-His frequency of M80A cyt c than of other His-ligated heme proteins indicates strong heme coordination and the imidazolate character of His18. Peaks attributed to the Fe-O2 stretching (νFe-O2) and O-O stretching (νO-O) modes of the oxygenated species of M80A cyt c were observed at 576 and 1148 cm-1, respectively, under an 16O2 atmosphere, whereas the frequencies decreased to 544 and 1077 cm-1, respectively, under an 18O2 atmosphere. The νFe-O2 mode of Hydrogenobacter thermophilus (HT) M59A cyt c552 was observed at 580 cm-1 under an 16O2 atmosphere, whereas the frequency decreased to 553 cm-1 under an 18O2 atmosphere, indicating that relatively high νFe-O2 frequencies are characteristic of c-type cyt proteins. By comparison of the simultaneously observed νFe-O2 and νO-O frequencies of oxygenated cyt c and other oxygenated His-ligated heme proteins, the frequencies tend to have a positive linear relationship; the νFe-O2 frequency increases when the νO-O frequency increases. The imidazolate character of the heme-coordinated His and strong Fe-O and O-O bonds are characteristic of cyt c and apparently related to the peroxidase activity when Met80 dissociates from the heme iron.
For humans to hand over an object to a robot, confirming the robot hand's position through their sensory organs (i.e., vision) is required. Only then can perform the hand-reaching task. This step is time-consuming and visual demand can also degrade other simultaneously conducted tasks performances. We assume that eliminating this step can lead to a rapid and precise reaching task. We propose a method to directly present the relative position of human-robot hands using phantom sensation-based vibrotactile stimulus on the human reaching arm. A multi-step vibrotactile cue; 1) gross motion, 2) fine motion, and 3) deadband, is provided to indicate the direction, distance to the target, and a signal indicating the reached target, respectively. The experimental result shows that users could precisely recognize the target position in a given shorter time. This indicates that humans can use the proposed method to initiate their ballistic movement for hand-reaching during the handover task.
Root hairs are single-celled tubular structures produced from the epidermis, which play an essential role in water and nutrient uptake from the soil. Therefore, root hair formation and elongation are controlled not only by developmental programs but also by environmental factors, enabling plants to survive under fluctuating conditions. Phytohormones are key signals that link environmental cues to developmental programs; indeed, root hair elongation is known to be controlled by auxin and ethylene. Another phytohormone, cytokinin, also affects root hair growth, while whether cytokinin is actively involved in root hair growth and, if so, how it regulates the signaling pathway governing root hair development have remained unknown. In this study, we show that the two-component system of cytokinin, which involves the B-type response regulators ARABIDOPSIS RESPONSE REGULATOR 1 (ARR1) and ARR12, promotes the elongation process of root hairs. They directly upregulate ROOT HAIR DEFECTIVE 6-LIKE 4 (RSL4) encoding a basic helix-loop-helix (bHLH) transcription factor that plays a central role in root hair growth, whereas the ARR1/12-RSL4 pathway does not crosstalk with auxin or ethylene signaling. These results suggest that cytokinin signaling constitutes another input onto the regulatory module governed by RSL4, making it possible to fine-tune root hair growth in changing environments.
Aim: Increasing evidence suggests that psychiatric disorders are linked to alterations in the mesocorticolimbic dopamine-related circuits. However, the common and disease-specific alterations remain to be examined in schizophrenia (SCZ), major depressive disorder (MDD), and autism spectrum disorder (ASD). Thus, this study aimed to examine common and disease-specific features related to mesocorticolimbic circuits. Methods: This study included 555 participants from four institutes with five scanners: 140 individuals with SCZ (45.0% female), 127 individuals with MDD (44.9%), 119 individuals with ASD (15.1%), and 169 healthy controls (HC) (34.9%). All participants underwent resting-state functional magnetic resonance imaging. A parametric empirical Bayes approach was adopted to compare estimated effective connectivity among groups. Intrinsic effective connectivity focusing on the mesocorticolimbic dopamine-related circuits including the ventral tegmental area (VTA), shell and core parts of the nucleus accumbens (NAc), and medial prefrontal cortex (mPFC) were examined using a dynamic causal modeling analysis across these psychiatric disorders. Results: The excitatory shell-to-core connectivity was greater in the all patients than in the HC group. The inhibitory shell-to-VTA and shell-to-mPFC connectivities were greater in the ASD group than in the HC, MDD, and SCZ groups. Furthermore, the VTA-to-core and VTA-to-shell connectivities were excitatory in the ASD group, while those connections were inhibitory in the HC, MDD, and SCZ groups. Conclusion: Impaired signaling in the mesocorticolimbic dopamine-related circuits could be an underlying neuropathogenesis of various psychiatric disorders. These findings will improve the understanding of unique neural alternations of each disorder and will facilitate identification of effective therapeutic targets. This article is protected by copyright. All rights reserved.
Aggregates of amphiphilic molecules can be used as drug carriers, for which the properties can be modified by mixing with other molecules such as cholesterol. It is important to understand the effects of such additives on the properties because they directly define the material functions. In this work, we investigated the effect of cholesterol on the formation and hydrophobicity of aggregates of sorbitan surfactants. As cholesterol changed its formation from micelles to vesicles, an increase in hydrophobicity was seen, particularly in the middle regions compared with the shallow and deep regions. We show that this gradual hydrophobicity is related to the localization of the embedded molecules. 4-Hydroxy-TEMPO and 4-carboxy-TEMPO were preferentially localized in the shallow region of the aggregates, whereas 4-PhCO2-TEMPO was preferentially localized in the deep region of the vesicle. The localization of molecules depends on their chemical structure. However, the localization of 4-PhCO2-TEMPO in micelles was not observed, despite the similar hydrophobicity in the hydrophobic region within the aggregates. The localization of embedded molecules was related to other properties, such as molecular mobility.
Herein, we designed and synthesized a thermally stable carboxybetaine copolymer with a one- or three-carbon spacer between ammonium and carboxylate groups (CBMA1 and CBMA3) to create an anti-nonspecific adsorption surface with the ability to immobilize antibodies. A series of controlled poly(N,N-dimethylaminoethyl methacrylate) was successfully prepared using reversible addition-fragmentation chain-transfer (RAFT) polymerization and was derived to carboxybetaine copolymers of poly(CBMA1-co-CBMA3) [P(CBMA1/CBMA3)] with various CBMA1 contents, including the homopolymers of CBMA1 and CBMA3. Thermal stability of the carboxybetaine (co)polymers was higher than that of the carboxybetaine polymer with a two-carbon spacer (PCBMA2). Further, we also evaluated nonspecific protein adsorption in fetal bovine serum and antibody immobilization on the substrate coated with P(CBMA1/CBMA3) copolymers using surface plasmon resonance (SPR) analysis. As the CBMA1 content increased, nonspecific protein adsorption on the P(CBMA1/CBMA3) copolymer surface decreased. Similarly, the immobilization amount of the antibody decreased as the CBMA1 content increased. However, the figure of merit (FOM), defined as the ratio of the amount of antibody immobilization to that of nonspecific protein adsorption, depended on the CBMA3 content; FOM was higher when the CBMA3 content was 20-40% than those of CBMA1 and CBMA3 homopolymers. These findings will help enhance the sensitivity of the analysis using molecular interaction measurement devices, such as SPR and quartz crystal microbalance.
To enhance the pH-responsiveness of poly(lactic acid) (PLA) particles, desired vanillin acetal-based initiators were synthesized and functional PLA was initiated at the chain end. PLLA-V6-OEG3 particles were prepared using polymers with various Mn values of 2400-4800 g/mol. PLLA-V6-OEG3 was appropriated to achieve a pH-responsive behavior under physiological conditions within 3 min via the six-membered ring diol-ketone acetal. Moreover, it was found that the polymer chain length (Mn) influenced the aggregation rate. TiO2 was selected as the blending agent to improve the aggregation rate. The PLLA-V6-OEG3 blended with TiO2 was found to accelerate the aggregation rate compared with that without TiO2, and the best ratio of polymer/TiO2 was 1:1. To study the effect of the chain end for stereocomplex polylactide (SC-PLA) particles, PLLA-V6-OEG4 and PDLA-V6-OEG4 were successfully synthesized. The obtained results of SC-PLA particle aggregation implied that the types of chain end and the molecular weight of polymer could influence the aggregation rate. The SC-V6-OEG4 blended with TiO2 could not make our target to aggregate under physiological conditions within 3 min. This study motivated us to control the particle aggregation rate under physiological conditions for applying as a target drug carrier which is significantly influenced by not only the molecular weight but also the hydrophilicity of the chain-end as well as the number of acetal bonds.
During development, the hypothalamus emerges from the ventral diencephalon and is regionalised into several distinct functional domains. Each domain is characterised by a different combination of transcription factors, including Nkx2.1, Nkx2.2, Pax6, and Rx, which are expressed in the presumptive hypothalamus and its surrounding regions, and play critical roles in defining each area. Here, we recapitulated the molecular networks formed by the gradient of Sonic Hedgehog (Shh) and the aforementioned transcription factors. Using combinatorial experimental systems of directed neural differentiation of mouse embryonic stem (ES) cells, as well as a reporter mouse line and gene overexpression in chick embryos, we deciphered the regulation of transcription factors by different Shh signal intensities. We then used CRISPR/Cas9 mutagenesis to demonstrate the mutual repression between Nkx2.1 and Nkx2.2 in a cell-autonomous manner; however, they induce each other in a non-cell-autonomous manner. Moreover, Rx resides upstream of all these transcription factors and determines the location of the hypothalamic region. Our findings suggest that Shh signalling and its downstream transcription network are required for hypothalamic regionalisation and establishment.
This paper analyzes a blockchain network forming a directed acyclic graph (DAG), called a DAG-type blockchain, from the viewpoint of graph algorithm theory. To use a DAG-type blockchain, NP-hard graph optimization problems on the DAG are required to be solved. Although various problems for undirected and directed graphs can be efficiently solved by using the notions of graph parameters, these currently known parameters are meaningless for DAGs, which implies that it is hopeless to design efficient algorithms based on the parameters for such problems. In this work, we propose a novel graph parameter for directed graphs called a DAG-pathwidth, which represents the closeness to a directed path. This is an extension of the pathwidth, a well-known graph parameter for undirected graphs. We analyze the features of the DAG-pathwidth and prove that computing the DAG-pathwidth of a DAG (directed graph in general) is NP-complete. Finally, we propose an efficient algorithm for a variant of the maximum k-independent set problem for the DAG-type blockchain when the DAG-pathwidth of the input graph is small.
The cortical motor cells (CMCs) in a legume pulvinus execute the reversible deformation in leaf movement that is driven by changes in turgor pressure. In contrast to the underlying osmotic regulation proper, the cell wall structure of CMCs that contributes to the movement has yet to be characterized in detail. Here, we report that the cell wall of CMCs has circumferential slits with low levels of cellulose deposition, which are widely conserved among legume species. This structure is unique and distinct from that of any other primary cell walls reported so far; thus, we named them "pulvinar slits." Notably, we predominantly detected de-methyl-esterified homogalacturonan inside pulvinar slits, with a low deposition of highly methyl-esterified homogalacturonan, as with cellulose. In addition, Fourier-transform infrared spectroscopy analysis indicated that the cell wall composition of pulvini is different from that of other axial organs, such as petioles or stems. Moreover, monosaccharide analysis showed that pulvini are pectin-rich organs like developing stems and that the amount of galacturonic acid in pulvini is greater than in developing stems. Computer modeling suggested that pulvinar slits facilitate anisotropic extension in the direction perpendicular to the slits in the presence of turgor pressure. When tissue slices of CMCs were transferred to different extracellular osmotic conditions, pulvinar slits altered their opening width, indicating their deformability. In this study, we thus characterized a distinctive cell wall structure of CMCs, adding to knowledge of repetitive and reversible organ deformation as well as the structural diversity and function of the plant cell wall.
Unlabelled: The patient's position may affect the bone mineral density (BMD) measurements; however, the extent of this effect is undefined. This CT image-based simulation study quantified changes in BMD induced by hip flexion, adduction, and rotations to recommend appropriate patient positioning when acquiring dual-energy x-ray absorptiometry images. Purpose: Several studies have analyzed the effect of hip rotation on the measurement of bone mineral density (BMD) of the proximal femur by dual-energy x-ray absorptiometry (DXA). However, as the effects of hip flexion and abduction on BMD measurements remain uncertain, a computational simulation study using CT images was performed in this study. Methods: Hip CT images of 120 patients (33 men and 87 women; mean age, 82.1 ± 9.4 years) were used for analysis. Digitally reconstructed radiographs of the proximal femur region were generated from CT images to calculate the BMD of the proximal femur region. BMD at the neutral position was quantified, and the percent changes in BMD when hip internal rotation was altered from -30° to 15°, when hip flexion was altered from 0° to 30°, and when hip abduction was altered from -15° to 30° were quantified. Analyses were automatically performed with a 1° increment in each direction using computer programming. Results: The alteration of hip angles in each direction affected BMD measurements, with the largest changes found for hip flexion (maximum change of 17.7% at 30° flexion) and the smallest changes found for hip rotation (maximum change of 2.2% at 15° internal rotation). The BMD measurements increased by 0.34% for each 1° of hip abduction, and the maximum change was 12.3% at 30° abduction. Conclusion: This simulation study quantified the amount of BMD change induced by altering the hip position. Based on these results, we recommend that patients be positioned carefully when acquiring DXA images.
The dopamine D1 receptor (D1R) is associated with schizophrenia, Parkinson's disease, and attention deficit hyperactivity disorder. Although the receptor is considered a therapeutic target for these diseases, its neurophysiological function has not been fully elucidated. Pharmacological functional MRI (phfMRI) has been used to evaluate regional brain hemodynamic changes induced by neurovascular coupling resulting from pharmacological interventions, thus phfMRI studies can be used to help understand the neurophysiological function of specific receptors. Herein, the blood oxygenation level-dependent (BOLD) signal changes associated with D1R action in anesthetized rats was investigated by using a preclinical ultra-high-field 11.7-T MRI scanner. PhfMRI was performed before and after administration of the D1-like receptor agonist (SKF82958), antagonist (SCH39166), or physiological saline subcutaneously. Compared to saline, the D1-agonist induced a BOLD signal increase in the striatum, thalamus, prefrontal cortex, and cerebellum. At the same time, the D1-antagonist reduced the BOLD signal in the striatum, thalamus, and cerebellum by evaluating temporal profiles. PhfMRI detected D1R-related BOLD signal changes in the brain regions associated with high expression of D1R. We also measured the early expression of c-fos at the mRNA level to evaluate the effects of SKF82958 and isoflurane anesthesia on neuronal activity. Regardless of the presence of isoflurane anesthesia, c-fos expression level was increased in the region where positive BOLD responses were observed with administration of SKF82958. These findings demonstrated that phfMRI could be used to identify the effects of direct D1 blockade on physiological brain functions and also for neurophysiological assessment of dopamine receptor functions in living animals.
The fruit-like aroma of two valine-derived volatiles, isobutanol and isobutyl acetate, has great impact on the flavor and taste of alcoholic beverages, including sake, a traditional Japanese alcoholic beverage. With the growing worldwide interest in sake, breeding of yeast strains with intracellular valine accumulation is a promising approach to meet a demand for sakes with a variety of flavor and taste by increasing the valine-derived aromas. We here isolated a valine-accumulating sake yeast mutant (K7-V7) and identified a novel amino acid substitution, Ala31Thr, on Ilv6, a regulatory subunit for acetohydroxy acid synthase. Expression of the Ala31Thr variant Ilv6 conferred valine accumulation on the laboratory yeast cells, leading to increased isobutanol production. Additionally, enzymatic analysis revealed that Ala31Thr substitution in Ilv6 decreased sensitivity to feedback inhibition by valine. This study demonstrated for the first time that an N-terminal arm conserved in the regulatory subunit of fungal acetohydroxy acid synthase is involved in the allosteric regulation by valine. Moreover, sake brewed with strain K7-V7 contained 1.5-fold higher levels of isobutanol and isobutyl acetate than sake brewed with the parental strain. Our findings will contribute to the brewing of distinctive sakes and the development of yeast strains with increased production of valine-derived compounds.
Recent advanced driver assistance systems’ (ADASs) control cars to avoid accidents, but few of them consider driver’s comfort. To realize comfortable driving, an ADAS must sense the driver’s emotions, especially when they are negative. Since emotions are reflected in a person’s physiological signals, they are informative for sensing emotions. However, it is unclear which signals are most useful for detecting a driver’s negative emotions. To examine the usefulness of each physiological signal, we implemented an emotion classifier (negative or non-negative) using sparse logistic regression for multimodal signals. This classifier was trained using a multimodal physiological signal dataset with negative emotion labels collected, while subjects were driving a vehicle. The resulting classifier successfully classifies emotions with an area under the curve of 0.74 and identifies the physiological signals that are useful for detecting negative emotions.
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929 members
Minoru Kubo
  • Center for Digital Green-innovation
Ming Huang
  • Graduate School of Information Science
Yoshito Otake
  • Graduate School of Information Science
Yuichiro Fujimoto
  • Graduate School of Information Science
Shiro Suetsugu
  • Division of Biological Science
8916-5 Takayama-cho, 630-0192, Ikoma, Nara, Japan
Head of institution
Kazuhiro Shiozaki