Development of a mobile magnetic resonance imaging system for outdoor tree measurements

By combining a 0.3 T permanent magnet with flexible rotation and translation mechanism, a probe with a local electromagnetic shielding, several electrical units, a mobile lift, and an electric wagon, a mobile magnetic resonance imaging (MRI) system was developed for outdoor tree measurements. 2D cross-sectional images of normal and diseased branches of a pear tree were acquired for measurements of T(1), T(2), proton density, and apparent diffusion constant (ADC). The ADC map clearly differentiated diseased from normal branches. A whole-day measurement of the ADC map demonstrated that microscopic water flow in the normal branch changed proportionally with solar radiation. Therefore, we have concluded that our mobile MRI system is a powerful tool for studies of plants in outdoor environments.     

Multi-cast key distribution: scalable,dynamic and provably secure construction

In this paper, we propose a two-round dynamic multi-cast key distribution (DMKD) protocol under the star topology with a central authentication server. Users can share a common session key without revealing any information of the session key to the server and can join/leave to/from the group at any time even after establishing the session key. Our protocol is scalable because communication and computation costs of each user are independent from the number of users. Also, our protocol is still secure if either private key or session-specific randomness of a user is exposed. Furthermore, time-based backward secrecy is guaranteed by renewing the session key for every time period even if the session key is exposed. We introduce the first formal security definition for DMKD under the star topology in order to capture such strong exposure resilience and time-based backward secrecy. We prove that our protocol is secure in our security model in the standard model.     

Parallel Implementation of the Nonlinear Semi-NMF Based Alternating Optimization Method for Deep Neural Networks

For computing weights of deep neural networks (DNNs), the backpropagation (BP) method has been widely used as a de-facto standard algorithm. Since the BP method is based on a stochastic gradient descent method using derivatives of objective functions, the BP method has some difficulties finding appropriate parameters such as learning rate. As another approach for computing weight matrices, we recently proposed an alternating optimization method using linear and nonlinear semi-nonnegative matrix factorizations (semi-NMFs). In this paper, we propose a parallel implementation of the nonlinear semi-NMF based method. The experimental results show that our nonlinear semi-NMF based method and its parallel implementation have competitive advantages to the conventional DNNs with the BP method.     

Multilingual author matching across different academic databases: a case study on KAKEN,DBLP, and PubMed

Scientometrics - Researchers often use their native languages to present and exchange ideas. To construct an individual author’s complete profile, a list of their English and non-English...     

Release kinetics of tritium generated in lithium-enriched Li2+xTiO3 by thermal neutron irradiation

Tritium release kinetics for Li_2+xTiO₃, the lithium-enriched Li₂TiO₃, was investigated by isochronal and isothermal annealing experiments. Tritium release by isochronal annealing showed that the dominant release stage was found at around 600 K. An additional release stage at lower temperature side was appeared with increasing excess lithium, which was attributed to the release of tritium trapped in Li₄TiO₄ structure. The dominant release stage was considered to a release of tritium trapped by irradiation defects. Isothermal annealing experiments indicated that tritium releases were controlled by diffusion process. The diffusion coefficient of Li_2.0TiO₃ was one order of magnitude as large as those of Li_2.2TiO₃ and Li_2.4TiO₃, although their activation energies were almost the same. These results showed that rate-determining step was the diffusion process of tritium in Li₂TiO₃ structure for Li_2+xTiO₃ and excess lithium would make diffusion coefficient smaller. Simulation of tritium-TDS spectra for Li_2.0TiO₃ has clarified that the TDS spectrum forLi_2.0TiO₃ can be demonstrated by using Arrhenius diffusion parameters obtained by isothermal annealing experiment in the present study.     

Xylanase from Marine Filamentous Fungus Pestalotiopsis sp. AN-7 Was Activated with Diluted Salt Solution Like Brackish Water

The genus Pestalotiopsis are endophytic fungi that have recently been identified as cellulolytic system producers. We herein cloned a gene coding for a xylanase belonging to glycoside hydrolase (GH) family 10 (PesXyn10A) from Pestalotiopsis sp. AN-7, which was isolated from the soil of a mangrove forest. This protein was heterologously expressed by Pichia pastoris as a host, and its enzymatic properties were characterized. PesXyn10A was produced as a glycosylated protein and coincident to theoretical molecular weight (35.3 kDa) after deglycosylation by peptide-NfF-glycosidase F. Purified recombinant PesXyn10A exhibited maximal activity at pH 6.0 and 50 °C, and activity was maintained at 90 % at pH 5.0 and temperatures lower than 30 °C for 24 h. The substrate specificity of PesXyn10A was limited and it hydrolyzed glucuronoxylan and arabinoxylan, but not β-glucan. The final hydrolysis products from birchwood xylan were xylose, xylobiose, and 1,2³-α-D-(4-O-methyl-glucuronyl)-1,4-β-D-xylotriose. The addition of metallic salts (NaCl, KCl, MgCl₂, and CaCl₂) activated PesXyn10A for xylan degradation, and maximal activation by these divalent cations was approximately 160 % at a concentration of 5 mM. The thermostability of PesXyn10A significantly increased in the presence of 50 mM NaCl or 5 mM MgCl₂. The present results suggest that the presence of metallic salts at a low concentration, similar to brackish water, exerts positive effects on the enzyme activity and thermal stability of PesXyn10A.     

Predicting quality decay in continuously passaged mesenchymal stem cells by detecting morphological anomalies

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Pick-and-verify: verification-based highly reliable picking system for various target objects in clutter

The reliability of picking task for various objects in clutter, as measured on the Amazon Picking Challenge, is far from the expectations of automation companies. Even if the best-performed team, who run object detection before picking the object, had picked a wrong object in the competition. In this paper, we propose a practical method to compose a highly reliable picking system with verification-based approach to reduce the rate of wrong picking and raise the reliability of picking ordered objects. In our approach, which we call pick-and-verify, the robot recognizes object twice: in clutter scene to detect the target and in hand after picking an object with less time loss and rise of reliability of picking the target. For grasping the detected object we do not assume its pose and it is actually the target object, instead, we adopt vision-based grasp planning for vacuum gripper with sensed 3-D point cloud. With the presented approach, the reliability of picking target objects raised 50%, and the score in the APC2015 competition has been improved to be close to the best-performed team by picking 9 out of 12 objects in 10 min with the same hardware in our previous system.     

Threonine 81 of the trp repressor of Escherichia coli plays an auxiliary role in the formation of the corepressor binding pocket

A mutational study was performed on the corepressor (Ltryptophan)binding site of the trp repressor of Escherichia coli. Threonine81, one of the residues forming the hydrophobic pocket of thebinding site, was replaced with Ser, Cys and Met by cassettemutagenesis. Biochemical characterization showed that all thesemutations caused a moderate decrease in tryptophan binding activity(free energy change 1 kcal/mol). The results suggested thatthe binding pocket is rather flexible in the vicinity of Thr81.On the other hand, the mutations produced a discernible decreasein the repressor activity in vivo, apparently by weakening oreliminating the hydrogen bond between Thr81 and the operatorDNA, as well as by introducing possible side-chain rearrangement.     

A heuristic approach for actuator layout designs in deformable mirror devices based on current value optimization

Structural and Multidisciplinary Optimization - Deformable mirrors are vital components in fundus imaging modality incorporating adaptive optics systems. The application of precisely controlled...