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He C.-X.,Zhejiang University | Tabata Y.,Frontier Engineering | Gao J.-Q.,Zhejiang University
International Journal of Pharmaceutics | Year: 2010

An increasing number of non-viral vectors are being developed for the use of gene delivery nowadays, among which cationic polymers and lipoplexes receive most attention. Most of these researches are focused on how to increase the transfection efficiency of non-viral vectors as well as the reduction of toxicity. In this review, we go over new strategies to reduce the toxicity of cationic polyplexes such as poly(ethylene-imine) and the construction of highly effective gene transfer vector lipoplexes. In addition, since transformation of gene expression system from two-dimensional (2D) substrate to 3D scaffold triggers far better transfection efficiency, the non-viral vectors applied in 3D transfection system have also been reviewed. © 2009 Elsevier B.V. All rights reserved.

Muto K.,Frontier Engineering | Imamura T.,University of Tokyo
Icarus | Year: 2017

The morphology of the dark polar oval seen at the Venus cloud top in visible and ultraviolet wavelengths has been unclear because the portion of the oval on the nightside is invisible. We analyzed in detail the variability of the whole shape of the oval by connecting VMC/Venus Express visible images taken on different days after shifting the images in zonal direction based on the estimated zonal advection speed. The shape of the oval was found to be changing over time between elongated shape and near-circular shape. The dominant period of this variation changes with time in the range of 200–350 Earth days, and does not seem to coincide with the orbital period, the rotation period, and the length of the day. This suggests that the variation of the oval shape is driven by some internal nonlinear process. The mechanism of oval formation is discussed. © 2017 Elsevier Inc.

Nishimoto Y.,Frontier Engineering | Kang K.,Osaka University | Yasuda M.,Osaka University
Organic Letters | Year: 2017

(Z)-β-Aryloxyalkenylzincs are synthesized stereoselectively via anti-carbozincation among alkynyl ethers, silyl ketene acetals, and ZnBr2. X-ray analysis revealed the structure of the zinc species is a mononuclear two-coordinate dialkenylzinc that is transformed into functionalized enol ethers as a single isomer in the reaction of various electrophiles. © 2017 American Chemical Society.

Vijayaprakash K.M.,Frontier Engineering | Sridharan N.,University of Madras
Journal of Pharmacology and Pharmacotherapeutics | Year: 2013

Till date, NYU MASCIS (New York University, Multicenter Animal Spinal Cord Injury Study) impactor and Ohio State University electromagnetic spinal cord injury device impactor were under use for simulating an experimental spinal cord injury in rodents; functional recovery being assessed through Basso, Beattie and Bresnahan (BBB) scoring method which is an open field behavior based scoring system. Although, the cited impactors are state-of-Art devices, affordability to scientists in developing and under developed countries is questionable. Since the acquisition of these impact devices are expensive, we designed a customized impact device based on the requirement, satisfying all the parameters to withstand a standard animal model for contusion type of spinal cord injury at the thoracic level without compromising the lesion reproducibility. Here, a spinal cord contusion is created using a blunt-force impactor in male Wistar rats. Our method gave consistent lesion effects as evaluated by behavior scoring methods. All the animals showed equal degree of performance in tests like narrow beam, inclined plane and horizontal ladder and in BBB scores (open field locomotor test). The aim of presenting our experience is to reinstate the fact that lack of affordability to get sophisticated instrumentation need not be a hurdle in the pursuit of science.

Chen Y.,Frontier Engineering | Kakuchi T.,Changchun University
Chemical Record | Year: 2016

In contrast to the conventional group transfer polymerization (GTP) using a catalyst of either an anionic nucleophile or a transition-metal compound, the organocatalyzed GTP has to a great extent improved the living characteristics of the polymerization from the viewpoints of synthesizing structurally well-defined acrylic polymers and constructing defect-free polymer architectures. In this article, we describe the organocatalyzed GTP from a relatively personal perspective to provide our colleagues with a perspicuous and systematic overview on its recent progress as well as a reply to the curiosity of how excellently the organocatalysts have performed in this field. The stated perspectives of this review mainly cover five aspects, in terms of the assessment of the livingness of the polymerization, limit and scope of applicable monomers, mechanistic studies, control of the polymer structure, and a new GTP methodology involving the use of tris(pentafluorophenyl)borane and hydrosilane. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

State-feedback model predictive control (MPC) of discrete-time linear periodic systems with time-dependent state and input dimensions is considered. The states and inputs are subject to periodically time-dependent, hard, convex, polyhedral constraints. First, periodic controlled and positively invariant sets are characterized, and a method to determine the maximum periodic controlled and positively invariant sets is derived. The proposed periodic controlled invariant sets are then employed in the design of least-restrictive strongly feasible reference-tracking MPC problems. The proposed periodic positively invariant sets are employed in combination with well-known results on optimal unconstrained periodic linear-quadratic regulation (LQR) to yield constrained periodic LQR control laws that are stabilizing and optimal. One motivation for systems with time-dependent dimensions is efficient control law synthesis for discrete-time systems with asynchronous inputs, for which a novel modeling framework resulting in low dimensional models is proposed. The presented methods are applied to a multirate nano-positioning system. © 2010 Elsevier Ltd. All rights reserved.

Ohkuma T.,Frontier Engineering | Arai N.,Hokkaido UniversityN13 W8
Chemical Record | Year: 2016

Catalytic asymmetric hydrogenation of ketones through the "metal-ligand cooperative mechanism" has been improved in terms of the efficiency, stereoselectivity, and scope of substrates by varying the arrangement of the catalyst structure and reaction conditions. Imino compounds are also smoothly converted to the optically active amines with appropriate catalysts. This type of catalyst exhibits excellent performance on the asymmetric isomerization of primary allylic alcohols into the optically active aldehydes. This personal account describes recent progress on these topics. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liang C.-H.,Frontier Engineering | Hwang C.-S.,Frontier Engineering
Journal of Alloys and Compounds | Year: 2010

A nanoscale hydrous manganese oxide used as an electrode in a supercapacitor was deposited onto a titanium substrate from an aqueous manganese acetate solution using the hydrothermal electrochemical method. The effect of deposition temperature on the characteristics of the manganese oxides was investigated. The capacitive characteristics of the manganese oxides were measured in sulfate electrolytes with various cations using cyclic voltammetry. The capacitive performances of the manganese oxide electrodes depend on the deposition temperature as well as the cations of electrolytes. A maximum capacitance of 244 F g -1 was obtained in Na 2SO 4 solution. The stability of manganese oxide was examined; after 1000 cycles, 80% of the initial capacitance remained. Crown Copyright © 2010.

Gondhalekar R.,Frontier Engineering | Imurab J.-I.,Tokyo Institute of Technology
Automatica | Year: 2010

Move-blocking lowers the computational complexity of model predictive control (MPC) problems by reducing the number of optimization variables. However, this may render states close to constraints infeasible. Thus move-blocking generally results in control laws that are restrictive; the controller domains may be unacceptably and unnecessarily small. Furthermore, different move-blocking strategies may result in controller domains of different sizes, all other factors being equal. In this paper an approach is proposed to design move-blocking MPC control laws that are least-restrictive, i.e. the controller domain is equal to the maximum controlled invariant set. The domains of different move-blocking controllers are then by design equal to each other. This allows comparison of differing move-blocking strategies based on cost performance only, without needing to consider domain size also. Thus this paper is a step towards being able to derive optimal move-blocking MPC control laws. © 2010 Elsevier Ltd. All rights reserved.

Agency: Department of Defense | Branch: Missile Defense Agency | Program: SBIR | Phase: Phase I | Award Amount: 99.77K | Year: 2010

This proposal provides an innovative solution to reduce the size and mass of a precision regulator used on typical liquid DACS systems. Novel friction-reducing Belleville washer designs and a secondary spring unit keep the regulator compact, simple and low weight while maintaining a +/-5% regulated pressure outlet tolerance. The simple temperature-compensating device keeps the size small and helps increase regulation precision. Low seat stress materials will keep the lockup pressure increase low.

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