Enhancement of Bone-Forming Ability on Beta-Tricalcium Phosphate by Modulating Cellular Senescence Mechanisms Using Senolytics

Various stresses latently induce cellular senescence that occasionally deteriorates the functioning of surrounding tissues. Nevertheless, little is known about the appearance and function of senescent cells, caused by the implantation of beta-tricalcium phosphate (β-TCP)—used widely in dentistry and orthopedics for treating bone diseases. In this study, two varying sizes of β-TCP granules (<300 μm and 300–500 μm) were implanted, and using histological and immunofluorescent staining, appearances of senescent-like cells in critical-sized bone defects in the calvaria of Sprague Dawley rats were evaluated. Parallelly, bone formation in defects was investigated with or without the oral administration of senolytics (a cocktail of dasatinib and quercetin). A week after the implantation, the number of senescence-associated beta-galactosidase, p21-, p19-, and tartrate-resistant acid phosphatase-positive cells increased and then decreased upon administrating senolytics. This administration of senolytics also attenuated 4-hydroxy-2-nonenal staining, representing reactive oxygen species. Combining senolytic administration with β-TCP implantation significantly enhanced the bone formation in defects as revealed by micro-computed tomography analysis and hematoxylin-eosin staining. This study demonstrates that β-TCP granules latently induce senescent-like cells, and senolytic administration may improve the bone-forming ability of β-TCP by inhibiting senescence-associated mechanisms.     

Assignment problem for system with precedence relationships among elements

We have studied the problem of assign elements to an ordered sequence of stations such that the precedence relations are satisfied. At this time, we can obtain the best evaluation value decided under certain constrained conditions to the assignment. This kind of problem includes the line balancing problem. In addition, this can be adjusted to various problems by changing the constrained condition and objective function. These problems can be shown as sequential partitions of the nodes of a directed acyclic graph into subsets. We especially consider the problem of finding a minimum total cost of the cut edge under the restriction of the size of block. In this paper, we propose the general framework for sequential partitions of directed acyclic graphs. We also describe an efficient algorithm that can be used to reduce computational requirements and, possibly, storage. We estimate that the complexity of the algorithm is the polynomial order, if structure of directed acyclic graphs is near parallel. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 121(2): 54–62, 1997     

D‐A1‐D‐A2 Backbone Strategy for Benzobisthiadiazole Based n‐Channel Organic Transistors: Clarifying the Selenium‐Substitution Effect on the Molecular Packing and Charge Transport Properties in Electron‐Deficient Polymers

Unipolar n‐type semiconducting polymers based on the benzobisthiadiazole (BBT) unit and its heteroatom‐substituted derivatives are for the first time synthesized by the D‐A₁‐D‐A₂ polymer‐backbone design strategy. Selenium (Se) substitution is a very effective molecular design, but it has been seldom studied in n‐type polymers. In this study, within the similar conjugated framework, the Se substitution effects on the optical, electrochemical, solid‐state polymer packing, electron mobility, and air‐stability of the target unipolar n‐type polymers are unraveled. Replacing the sulfur (S) atom in the thiadiazole heterocycles with the Se atom leads to narrower bandgaps and deeper lowest unoccupied molecular orbital (LUMO) levels of the n‐type polymers. Furthermore, the Se‐substituted polymer (pSeN‐NDI) shows shorter lamellar packing distances and stronger edge‐on π–π stacking interactions than its S‐counterpart (pSN‐NDI), as observed by the two‐dimensional grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) patterns. With the deeper LUMO level and thin‐film microstructures suitable for transistors, pSeN‐NDI exhibits four‐fold higher electron mobilities (μ_e) than pSN‐NDI. However, the other Se‐containing polymer, pSeS‐NDI, forms rather amorphous film structures, which is caused by its limited thermal stability and decomposition during the thermal annealing processes, thus giving rise to a lower μ_e than its S‐counterpart (pBBT‐NDI). Most importantly, pBBT‐NDI demonstrates an electron mobility of 0.039 cm² V^?1 s^?1, which is noticeable among the unipolar n‐type polymers based on the BBT and its analogs.     

Communication Interface with Eye-Gaze and Head Gesture Using Successive DP Matching and Fuzzy Inference

This paper proposes a communication interface with eye-gaze and head gesture. Visual sensorimotor integration with eye-head cooperation is considered, especially head gesture accompanied with vestibulo-ocular reflex is used for selecting object in the screen. Eye-mark recorder and motion tracking system were used to tracking eye movement and head movement, respectively. Nonverbal response animation with eye contact was introduced in the interaction system. In identifying the head gesture, we adopted a modified dynamic programming matching method and fuzzy inference.     

PID landing orbit motion controller for an indoor blimp robot

Blimp robots are attractive as indoor flying robots because they can float in the air, land safely with low energy, and stay in motion for a long time compared with other flying robots. However, controlling blimp robots is difficult because they have nonlinear characteristics, are influenced by air streams, and can easily be influenced by inertia. Therefore, a robust and adaptive control system is needed for blimp robots. The applied research that has studied the features of indoor flying robots in recent years has prospered. Operating an indoor blimp robot for a long time is difficult because the payload is small, multiple batteries cannot be stacked, and the design of a thruster that gives freedom to the entire blimp robot is difficult. Therefore, an autonomous charge that allows operation for a long time is needed. We have developed a method of landing with orbital control of the charge point that gives autonomy to a blimp robot. The possibility of landing with orbital control is shown. This work was presented in part at the 10th International Symposium on Artificial Life and Robotics, Oita, Japan, February 4–6, 2005 An erratum to this article is available at .     

A product modeling system for top-down design of machine assembly with kinematic motion

The objective of this research is to develop a product modeling system to support mechanism design from the beginning of the design. The system must cope with two aspects of the design process which are top-down design and preliminary design. The current capabilities of existing CAD and CAE systems are not sufficient to support these two aspects. In this research a modeling method with an abstract model and an incompletely defined model is proposed. The mechanism is presented by constraints and depault values because constraints are suitable for representing the abstract model for a mechanism and default values are useful to supplement an incompletely defined model. We also introduce module-based modeling with mechanism modules corresponding directly to the functionalities of the mechanism and show that it is suitable for top-down design. Incomplete constraints are solved with default values so that the shape and location of the incompletely defined model can be modified and the motion of the model can be simulated. Finally, we illustrate the mechanism modeling system with some examples.     

Polymerization of 2-dibutylamino-1,3,5-triazine-4,6-dithiol on wire during friction process

2-Dibutylamino-1,3,5-triazine-4,6-dithiol (DB) and a mixture of DB and triallylisocyanurate (TAIC) were used as a lubricant during steel wire drawing due to a dry process. DB gave a polymer film with 180 nm in thickness to wire surfaces during the wire drawing. The polymer film had a disulfide structure on the backbone and contained a small amount of DB monomer and olygomer. Molecular weight and polymer weight increased with the drawing rate. The mixture of DB and TAIC gave mainly a three-dimensional polymer film with 225 nm in thickness to wire surfaces during drawing. The polymer film insoluble in THF had mono and disulfide structures and contained a small amount of linear polymer, DB, and TAIC. Such tribological polymerizations are estimated as follows: DB produces dithiyl radicals on a nascent surface formed during drawing and in the presence of oxygen and heat. The dithiyl radicals were polymerized by coupling with each other to give disulfide bonds or added to allyl groups in TAIC to give monosulfide bonds. It is concluded that this technique should be possible to use for unifying metal processing and surface treatment. © 1995 John Wiley & Sons, Inc.     

A Study on the Effect of Air on the Dynamic Motion of a MEMS Device and Its Shape Optimization

The authors propose a new design concept for controlling the deflection of a micro-membrane with the aid of its thickness distribution for realizing a prescribed design in the MEMS. As an example, the authors treat a micro air pump that comprises a micro-membrane. The membrane is actuated by an electrostatic force. The membrane deflects and thus the deflection is influenced by the air pressure and the electrostatic field. This is a highly complicated system. To find out a proper thickness distribution, the authors use the genetic algorithm that is appropriate to reduce the searching space of solution.     

Suppression of hydrogen-induced blisters in SK4 carbon steel alloy by friction stir processing

The feasibility of using friction stir-processing technique as a microstructural refining method for preventing hydrogen-induced blisters of SK4 carbon steel alloy containing microstructure of hard cementite particles in a ductile ferrite matrix was examined. Amount and size of hydrogen-induced blisters decreased in the stirred layers with increasing rotation speed and completely disappeared when rotation speed attained 400 rpm because of the formation of a hard and fine microstructure consisting of pearlite, martensite, and retained austenite instead of that containing hard spheroidized cementite particles in a soft ferrite matrix. Interfaces between ferrite matrix and cementite particles were the preferential sites for the hydrogen blisters initiation.