Physiological significance of ATP and glutamate release from astrocytes

　　　Astrocytes, the major glial cell type in the CNS, have been considered to be passive bystanders that merely provide support to neuronal networks. However astrocyte is now recognized as one of the active elements that directly modulate brain functions. Astrocytes sense and integrate synaptic activity and, depending on intracellular Ca2+ levels, release gliotransmitters (e.g. glutamate, ATP and D-serine) that have feedback actions on neurons. Although these reports provided clues that astrocytes are the active components in the brain, they did not analyze the temporal and spatial pattern of gliotransmitters release from astrocytes. To examine the release of gliotransmitters, such as ATP and glutamate, he applied imaging techniques visualizing ATP and glutamate released from astrocytes. 　　　Luciferin-luciferase solution was applied to the extracellular fluid of astrocytes to visualize ATP release. To visualize glutamate release, glutamate optic sensor (EOS) was applied. This specific probe for detecting glutamate is a hybrid molecule consisting of glutamate-binding protein (AMPA receptor GluR2 subunit extracellular domain as a glutamate-binding protein) and a small-molecule fluorescent dye. He successfully observed ATP or glutamate release from astrocytes and applied these technologies to observe spatial and temporal pattern of gliotransmitters release. 　　　Many researchers found that the astrocytic intracellular calcium responses are co-related with the functions of astrocytes. To reveal the significance of intracellular calcium elevation of astrocytes on the gliotransmitter release, he tried to obtain the spatio-temporal information using these technologies combined with the calcium imaging technology. By ATP (1 μM or higher) stimulation, intracellular calcium elevation was observed in all astrocytes. However, under the same condition, only few(ca.3?7%) released glutamate. A similar phenomenon was observed in glutamate-evoked ATP release from astrocytes; even though all astrocytes showed increased intracellular calcium levels, small proportion of astrocytes released ATP by glutamate stimulation (ca. 1%). It was expected that astrocytes which showed intracellular calcium elevation release gliotransmitters, however, my results were totally different.　　　Pharmacological approaches revealed that P2X and P2Y receptors showed different patterns of intracellular calcium elevation, however, a similar pattern of glutamate release was evoked by P2X and P2Y stimulations. For the glutamate stimulation, it was suggested that the subtype 5 of metabotrophic glutamate receptor was responsible to increase intracellular calcium in astrocytes and to release ATP from astrocytes. The glutamate stimulation evoked calcium waves among astrocytes, and then astrocytes released ATP around 200 seconds after glutamate application. 　　　His experiments using cultured astrocytes revealed following things: 1) intracellular calcium elevation was not enough to evoke gliotransmitter release, 2) direct relationship between glutamate release and intracellular calcium elevation evoked by ATP stimulation is low, 3) ATP release evoked by glutamate stimulation had relevance to the intracellular calcium elevation which represent the activation of astrocytes. For the first time, glitransmitter release was successfully visualized and the mechanisms of gliotransmitter release were revealed through these imaging technologies

Visual Odometry of a Low-Profile Pallet Robot Based on Ortho-Rectified Ground Plane Image from Fisheye Camera

This study presents a visual-only odometry technique of a low-profile pallet robot using image feature tracking in ground plane images generated from a fisheye camera. The fisheye camera is commonly used in many robot vision applications because it provides a larger field of view (FoV) around a robot. However, because of the large radial distortion, the fisheye image is generally converted to a pinhole image for visual feature tracking or matching. Although the radial distortion can be eliminated via image undistortion with the lens calibration parameters, it causes several side effects, such as degraded image resolution and a significant reduction in the FoV. In this paper, instead of using the pinhole model, we propose to generate a ground plane image (GPI) from the fisheye image. GPI is a virtual top-view image that only contains the ground plane at the front of the robot. First, the original fisheye image is projected to several virtual pinhole images to generate a cubemap. Second, the front and bottom faces of the cubemap are projected to a GPI. Third, the GPI is homographically transformed again to further reduce image distortion. As a result, an accurate ortho-rectified ground plane image is obtained from the virtual top-view camera. For visual odometry using the ortho-rectified GPI, a number of 2D motion vectors are obtained using feature extraction and tracking between the previous and current frames in the GPI. By calculating a scaled motion vector, which is the measurement of the virtual wheel encoder of the mobile robot, we estimate the velocity and steering angle of the virtual wheel using the motion vector. Finally, we estimate the pose of the mobile robot by applying a kinematic model to the mobile robot

Stable Thermally Activated Delayed Fluorescence‐Sensitized Red Fluorescent Devices through Physical Suppression of Dexter Energy Transfer

Abstract To date, thermally activated delayed fluorescence‐sensitized fluorescent organic light‐emitting diodes (TSF‐OLEDs) have undergone substantial research to achieve high efficiency and good operational stability in wide color gamut regions. Usually, to achieve a highly efficient TSF device, the Förster resonance energy transfer rate (kFRET) should be enhanced, whereas the Dexter energy transfer rate (kDET) should be suppressed. Even though highly efficient devices are achieved in all RGB color regions by satisfying the BT2020 requirements, achieving long device lifetimes is still challenging. Herein, a highly stable red‐TSF device is reported by adopting a new Dexter energy transfer suppressive layer (DSL) adjacent to the main emissive layer. Here, the DSL can improve the distance between the excitons generated from the host‐TADF layer and the final dopant (FD) of the TSF device, which allows for suppressing the kDET. Furthermore, the detailed device mechanistic pathways are analyzed by varying the DSL doping concentration with different thicknesses in different positions. Among the fabricated devices, the DSL‐TSF device manifested a longer operational lifetime (LT95) over 370 h at 5000 cd m‐2 and reduced efficiency roll‐off compared with TSF devices. Such long lifetime and high stability in DSL‐TSF OLEDs are owing to the decreased kDET than TSF devices

Predicting Postoperative Lung Function in Patients with Lung Cancer Using Imaging Biomarkers

There have been previous studies conducted to predict postoperative lung function with pulmonary function tests (PFTs). Computing tomography (CT) can quantitatively measure small airway walls’ thickness, lung volume, pulmonary vessel volume, and emphysema area, which reflect the severity of respiratory diseases. These measurements are considered imaging biomarkers. This study aimed to predict postoperative lung function with imaging biomarkers. A retrospective analysis of 79 patients with lung cancer who had undergone lung surgery was completed. Postoperative lung function measured by forced expiratory volume in one second (FEV1) was defined as an outcome. Preoperative clinico-pathological parameters and imaging biomarkers representing airway walls’ thickness, severity of emphysema, total lung volume, and pulmonary vessel volume were measured quantitatively in chest CT by an automated segmentation software, AVIEW COPD. Pi1 was defined as the first percentile along the histogram of lung attenuation that represents the degree of emphysema. Wafw was defined as the airway thickness, which was calculated by the full-width at half-maximum method. Logistic and linear regressions were used to assess these variables. If the actual postoperative FEV1 was higher than the postoperative FEV1 projected by a formula, the group was considered to be preserved. Among the 79 patients, 16 of the patients were grouped as a non-preserved group, and 63 of them were grouped as a preserved group. The patients in the preserved FEV1 group had a higher vessel volume than the non-preserved group. Pi1 and Wafw were independent predictors of postoperative lung function. Imaging biomarkers can be considered significant variables in predicting postoperative lung function in patients with lung cancer

A Safe Delegation Method for Web Services in Pervasive Computing Environments

Web Services are the new building block of today’s Internet, and provides interoperability among heterogeneous distributed systems. In this environment, security is one of the most critical issues. An attacker may expose user privacy and service information without authentication. Furthermore, in the pervasive computing environment, the users of web services must temporarily delegate some or all of their rights to an agent to perform actions on their behalf. This results in the exposure of user’s privacy information by agents. We present a delegation model to support secure web services in pervasive computing environments. In order to support privacy protection, service confidentiality, and assertion integrity, encryption and a digital signature mechanism is deployed. We build web service management server based on XACML, in order to manage services and policies of web service providers. SAML is extended, in order to declare delegation assertions transferred to web service providers, by delegation among agents. Key words: XACML, SAML, Agen

Nuanced contribution of gut microbiome in the early brain development of mice

ABSTRACTThe complex symbiotic relationship between the mammalian body and gut microbiome plays a critical role in the health outcomes of offspring later in life. The gut microbiome modulates virtually all physiological functions through direct or indirect interactions to maintain physiological homeostasis. Previous studies indicate a link between maternal/early-life gut microbiome, brain development, and behavioral outcomes relating to social cognition. Here we present direct evidence of the role of the gut microbiome in brain development. Through magnetic resonance imaging (MRI), we investigated the impact of the gut microbiome on brain organization and structure using germ-free (GF) mice and conventionalized mice, with the gut microbiome reintroduced after weaning. We found broad changes in brain volume in GF mice that persist despite the reintroduction of gut microbes at weaning. These data suggest a direct link between the maternal gut or early-postnatal microbe and their impact on brain developmental programming

iPSC-Derived MSCs Are a Distinct Entity of MSCs with Higher Therapeutic Potential than Their Donor-Matched Parental MSCs

Mesenchymal stromal cells derived from induced pluripotent stem cells (iMSCs) have been proposed as alternative sources of primary MSCs with various advantages for cell therapeutic trials. However, precise evaluation of the differences between iMSCs and primary MSCs is lacking due to individual variations in the donor cells, which obscure direct comparisons between the two. In this study, we generated donor-matched iMSCs from individual bone marrow-derived MSCs and directly compared their cell-autonomous and paracrine therapeutic effects. We found that the transition from primary MSCs to iMSCs is accompanied by a functional shift towards higher proliferative activity, with variations in differentiation potential in a donor cell-dependent manner. The transition from MSCs to iMSCs was associated with common changes in transcriptomic and proteomic profiles beyond the variations of their individual donors, revealing expression patterns unique for the iMSCs. These iMSC-specific patterns were characterized by a shift in cell fate towards a pericyte-like state and enhanced secretion of paracrine cytokine/growth factors. Accordingly, iMSCs exhibited higher support for the self-renewing expansion of primitive hematopoietic progenitors and more potent immune suppression of allogenic immune responses than MSCs. Our study suggests that iMSCs represent a separate entity of MSCs with unique therapeutic potential distinct from their parental MSCs, but points to the need for iMSC characterization in the individual basis