Proposal for a new magnet lattice for an electron storage ring for a high brightness synchrotron radiation source

A new magnet lattice, named “variable emittance”, for an electron storage ring dedicated to synchrotron radiation is proposed. The lattice has a high flexibility to meet the requirements for a high performance undulator as well as for conventional synchrotron radiation from a bending magnet. Tune shifts due to magnet imperfections were simulated and it is found that the periodic solution of the optics is stable enough except for a very high tune region. The effects of undulators and wigglers on the stored beam were studied and a correction for the tune shift is found necessary for high field wigglers.     

Anisotropy in ac losses near the irreversibility field of Bi2Sr2CaCu2O8

The ac susceptibility under a biased dc field near the irreversibility field (H _irr) of a Bi₂Sr₂CaCu₂O₈ single crystal has been measured. The frequency dependence, the ac-power dependence, and the nearly lossless character of the?″ vs.H _dc curve forH∥a-axis have been roughly explained from a reversible (elastic) fluxoid motion, while those forH∥ c-axis have been explained from a thermally assisted flux-flow (TAFF) model. The obtained parameters are discussed in relation to anisotropic flux-pinning mechanisms in the layered structure of this compound.     

Evaluation of fluorescence emitting characteristics of a microparticle by illumination angle scanning utilizing a resin-based monolithic TAS chip

Microsystem Technologies - An optical sensor, such as a light waveguide implemented total analysis system (TAS), is one of the functional components that will be needed to realize a...     

Effect of Notch-Root Radius on the Fracture Toughness of a Fine-Grained Alumina

The dependence of K _Ic on the notch-root radius has been examined for a notch radius as small as a few micrometers in a dense, fine-grained, polycrystalline alumina ceramic. The notch radius can be systematically varied by using a semimanual procedure in a special jig which polishes out rather than cuts the specimen. K _Ic is independent of the notch sharpness for notch-root radii < 10 μm. The results are critically compared with those obtained by other standard techniques and discussed in terms of residual compressive stresses introduced during the notching procedure.     

Performance optimization of iterative receiver for wireless communications based on realistic channel conditions

Adopting orthogonal frequency division multiplexing (OFDM) to low-density parity check (LDPC) coded multiple-input multiple-output (MIMO) is attractive scheme for wireless communication systems. An iterative receiver design for LDPC coded MIMO-OFDM system is proposed as the foundation for enhancing the wireless link performance can deliver the coverage, speed, throughput and reliability. However, in previous works, evaluations are basically assumed for a certain channel scenario and it is inefficient in incorporating different channel scenarios. The aim of this paper is to improve the system range for equivalent error rate, while not significantly increasing system complexity compared to conventional iterative receiver solution under realistic channel environment. We show that our proposed iteration adaptation at receiver can considerably adopt the system to realistic change environment, and reach very high reliability. Simulations of our optimization reveal superior error rate performance and lower computational cost vs. conventional LDPC coded MIMO OFDM system. Our simulation results also capture the effects of realistic vs. typical channel fading types (i.e., Rician vs. Rayleigh, respectively) and fading parameter models (average vs. random azimuth spread and K factor) on system performance and complexity.     

An optimization technique for lowering the iteration bound of DSP programs

The throughput of a parallel execution of a DSP algorithm is limited by the iteration bound, which is the minimum period between the starts of consecutive iterations. It is given byT _i=max (T _i/D _i), whereT _i andD _i are the total time of operations and the number of delays in loopi, respectively. The execution throughput of a DSP algorithm can be increased by reducing theT _is, and this reduction can be realized by taking as many operations as possible out of loops without changing the semantic of the calculation. Since many DSP algorithms extensively use the four basic arithmetic operations, a simple and effective way of doing this reduction is to apply commutativity, associativity and distributivity on these operations. This paper presents an optimization technique, calledLoop Shrinking, which reduces the iteration bound by using the above method. Loop Shrinking is based on a heuristic method which is time-efficient for simple cases but can also tackle complex examples. An implementation of Loop Shrinking is presented in this article. The results show that it can yield a reduction in the iteration bound near or equal to careful hand-tuning.     

A physical model for engine control design via role state variables

The present paper describes a model representation of the multi-cyclic phenomena of a multi-cylinder engine system. The model is simplified for the implementation of a practical engine controller. The simplified model is described by physically meaningful state variables, which enables controller designers to effectively consider practical objectives and constraints. The proposed approach consists of two steps. First, an approximate analytical discrete-crank angle model, which is a periodic state equation, is derived from the gas equations, the conservation laws, and the motion dynamics. Second, the concept of role state variables is proposed to transform the periodic state equation into a time-invariant state equation. The stabilizability and detectability of the time-invariant state equation are shown to be equivalent to those of the periodic state equation. The time-invariant state equation is used to design cold start feedforward and feedback controllers.     

Porphyromonas gingivalis Fimbriae Induce Osteoclastogenesis via Toll-like Receptors in RAW264 Cells

The effect of Mfa1 fimbriae of Porphyromonas gingivalis on the progression of bone resorption remains unclear, especially compared with another fimbriae, FimA. We investigated the effect of Mfa1 on osteoclastogenesis together with FimA. We also investigated the role of Toll-like receptors (TLRs) in Mfa1 recognition during osteoclast differentiation. Receptor activator of nuclear factor κβ ligand (RANKL)-prestimulated RAW264 cells were used to examine the effects of purified Mfa1 fimbriae. The number of osteoclasts was examined by tartrate-resistant acid phosphate (TRAP) staining, osteoclast activation was investigated by bone resorption assays, and gene expression of differentiation markers was examined by quantitative real-time PCR. Transfection of Tlr2 and Tlr4 siRNAs into RAW264 cells was also employed and their role in Mfa1 recognition was investigated. Mfa1 effectively induced the formation of TRAP-positive multinucleated cells and activated osteoclasts. Mfa1 also increased gene expression of Acp5, Mmp9, and Ctsk in RANKL-prestimulated RAW264 cells compared with the control. The osteoclastogenesis induced by Mfa1 was significantly decreased in cells transfected with Tlr2 or Tlr4 siRNAs compared with control siRNA. Our results revealed the role of Mfa1 fimbriae in osteoclastogenesis that may contribute to the partial elucidation of the mechanisms of periodontal disease progression and the development of new therapeutic strategies.     

Quick and Spontaneous Transformation between [3Fe–4S] and [4Fe–4S] Iron–Sulfur Clusters in the tRNA-Thiolation Enzyme TtuA

Iron–sulfur (Fe–S) clusters are essential cofactors for enzyme activity. These Fe–S clusters are present in structurally diverse forms, including [4Fe–4S] and [3Fe–4S]. Type-identification of the Fe–S cluster is indispensable in understanding the catalytic mechanism of enzymes. However, identifying [4Fe–4S] and [3Fe–4S] clusters in particular is challenging because of their rapid transformation in response to oxidation–reduction events. In this study, we focused on the relationship between the Fe–S cluster type and the catalytic activity of a tRNA-thiolation enzyme (TtuA). We reconstituted [4Fe–4S]-TtuA, prepared [3Fe–4S]-TtuA by oxidizing [4Fe–4S]-TtuA under strictly anaerobic conditions, and then observed changes in the Fe–S clusters in the samples and the enzymatic activity in the time-course experiments. Electron paramagnetic resonance analysis revealed that [3Fe–4S]-TtuA spontaneously transforms into [4Fe–4S]-TtuA in minutes to one hour without an additional free Fe source in the solution. Although the TtuA immediately after oxidation of [4Fe–4S]-TtuA was inactive [3Fe–4S]-TtuA, its activity recovered to a significant level compared to [4Fe–4S]-TtuA after one hour, corresponding to an increase of [4Fe–4S]-TtuA in the solution. Our findings reveal that [3Fe–4S]-TtuA is highly inactive and unstable. Moreover, time-course analysis of structural changes and activity under strictly anaerobic conditions further unraveled the Fe–S cluster type used by the tRNA-thiolation enzyme.