Analysis/Reduction of Residual Amplitude Modulation in Phase/Frequency Modulation by an EOM

Summary form only given. Frequency modulation (FM) is a powerful tool for sensitive spectroscopy and laser frequency stabilization. The high potential modulation frequency and FM format makes it easier to achieve shot-noise limit detection. Usually the laser frequency is modulated by an external frequency modulator such as an electrooptic modulator (EOM). However to obtain a pure FM signal is not easy because of residual amplitude modulation (RAM) arising by several effects: 1) etalon effects by light scattering within and at surfaces of the EOM crystal; 2) piezo-electric response of the EOM crystal, leading to beam steering and/or spatial position dither; 3) spatial inhomogeneity of modulation field in EOM crystal, leading to angular deviation of the beam and/or impure FM when part of the beam is selected; 4) and temperature dependence of the RAM associated with changes of the EOM crystal\u27s optical path and birefringence. RAM can easily be in the percent domain, and degrades the sensitivity in the FM spectroscopy, and also gives undesirable frequency offsets from the frequency reference. To solve the RAM problem, we measured and analyzed the RAM experimentally. A new active RAM suppression system is suggested

ヒト ガンサイボウ カブ ニオケル エンセキガイセン コウカ ノ イデンシ ハツゲン カイセキ

Far-infrared radiation (FIR) is electromagnetic radiation with wavelengths between 4 and 1000μm. The available evidence indicates that in vivo and in vitro irradiation by FIR has many biological effects, but how it affects cells is not well understood. Our previous studies using A431, HSC3 and Sa3 cells suggested that FIR inhibited cell proliferation by delaying the cell cycle in the G_2/M stage in HSC3 cells, while necrotic cells of Sa3 cells slightly increased. In addition, the basal expression of HSP70 was higher in FIR-insensitive A431 cells than in FIR-sensitive HSC3 and Sa3 cells, suggesting that the suppressive effect of FIR depends on HSP70 expression level in vitro. During in vivo analysis, FIR inhibited tumor growth in the A431 tumorigenesis model mouse by inhibiting the expression of matrix metalloprotease-1, 9, 10, and 13. In this study, we used a tissue culture incubator that can continuously irradiate cells with FIR, and we used it to examine the effects of a body temperature range of FIR on five human cancer cell lines, namely A431 (vulva), A549 (lung), HSC3 (tongue), MCF7 (breast), and Sa3 (gingiva). We found that FIR inhibits cell proliferation and induces cell hypertrophy in A549, HSC3, and Sa3 cells. In contrast, FIR did not inhibit cell proliferation, or cause cell hypertrophy in A431 or MCF7 cells. Also, FIR did not cause apoptosis in any of the five cell lines tested. cDNA microarray analysis revealed that FIR suppressed the expression of cell proliferation-related and stress-responsive genes in FIR-sensitive cell lines (A549, HSC3, and Sa3). Additionally, ATF3, in particular, was identified as a key mediator of the FIR effect. Overexpression of ATF3 inhibited the cell proliferation of A431, HSC3, and Sa3 cells, and knockdown of ATF3 mRNA using an antisense oligonucleotide suppressed FIR-induced growth arrest in HSC3 cells. In addition, the basal expression level of HSP70A mRNA was higher in A431 and MCF7 cells than in the FIR-sensitive A549, HSC3 and Sa3 cells. Also, HSP70A showed a high correlation with the growth rate out of the 35 HSP genes on the microarray. These results indicate that the body temperature range of FIR radiation suppresses the proliferation of A549, HSC3, and Sa3 cells, and it appears that ATF3 and HSP70 play important roles in this effect

Unitary IIB Matrix Model and the Dynamical Generation of the Space Time

We propose a unitary matrix model as a regularization of the IIB matrix model of Ishibashi-Kawai-Kitazawa-Tsuchiya (IKKT). The fermionic part is incorporated using the overlap formalism in order to avoid unwanted ``doublers'' while preserving the global gauge invariance. This regularization, unlike the one adopted by IKKT, has manifest U(1)^10 symmetry, which corresponds to the ten-dimensional translational invariance of the space time. We calculate one-loop effective action around some typical BPS-saturated configurations in the weak coupling limit. We also discuss a possible scenario for the dynamical generation of the four-dimensional space time through spontaneous breakdown of the U(1)^10 symmetry in the double scaling limit.Comment: 30 pages, 1 Postscript figure, The final version accepted by NP

Effect of moisture in κ-carrageenan films on their tensile and relaxation behavior studied by correlation between stress and birefringence

A picture on the molecular level describing the deformation and the following relaxation of κ-carrageenan chains has been proposed based on the three-domain structural model for κ-carrageenan films and on the idea of the modified stress-optical rule. The uniaxial tensile and the relaxation behavior for dry and moist κ-carrageenan films has been examined by using a homemade apparatus available for the simultaneous mechanical and birefringence measurements. It has been suggested that the continuous amorphous phase of κ-carrageenan in the dry film is deformed together with the local glass component, and only the glass component relaxes in the following process. On the other hand, concerning the moist film, the crosslinks of κ-carrageenan aggregates in addition to the continuous phase are movable with deformation, while the following relaxation is attributed only to the unbridged κ-carrageenan chains in the continuous phase

Four-Dimensional N=1 Supersymmetric Yang-Mills Theory on the Lattice without Fine-Tuning

We propose a method to formulate four-dimensional N=1 super Yang-Mills theory on the lattice without fine-tuning. We first show that four-dimensional Weyl fermion in a real representation, which is equivalent to Majorana fermion, can be formulated using the domain wall approach with an addition of a Majorana mass term only for the unwanted mirror fermion. This formalism has manifest gauge invariance. Fermion number conservation is violated only by the additional Majorana mass term for the mirror fermion and the violation is propagated to the physical fermion sector through anomalous currents. Due to this feature, the formalism, when applied to the gluino in the present case, ensures the restoration of supersymmetry in the continuum limit without fine-tuning, unlike the proposal by Curci and Veneziano.Comment: 7 pages, TeX, no figure, final version accepted by Physics Letters B.; explanation for exact chiral symmetry in L_5->\infty limit adde

Dynamical Aspects of Large N Reduced Models

We study the large N reduced model of D-dimensional Yang-Mills theory with special attention to dynamical aspects related to the eigenvalues of the N by N matrices, which correspond to the space-time coordinates in the IIB matrix model. We first put an upper bound on the extent of space time by perturbative arguments. We perform a Monte Carlo simulation and show that the upper bound is actually saturated. The relation of our result to the SSB of the U(1)^D symmetry in the Eguchi-Kawai model is clarified. We define a quantity which represents the uncertainty of the space-time coordinates and show that it is of the same order as the extent of space time, which means that a classical space-time picture is maximally broken. We develop a 1/D expansion, which enables us to calculate correlation functions of the model analytically. The absence of an SSB of the Lorentz invariance is shown by the Monte Carlo simulation as well as by the 1/D expansion.Comment: 41 pages, LaTeX, 15 eps figures; comments added for the well-definedness of the models and for a related referenc

Quasinormal modes of stringy black holes

String theory is a promising candidate for a fundamental quantum theory of all interactions including Einstein gravity. Some solutions in string theory can be interpreted as black holes. Using the semi-analytic method and WKB method,the quasinormal modes(QNMs)of 1+1 dimensional black hole in string theory are studied.The QNMs of 1+3 dimensional black hole in string theory are also calculated through numerical approach.The numerical investigation has shown that the late time gravitational oscillation of the black hole under an external perturbaton is dominated by certain QNMs.Comment: 2 figure

Stereoselective synthesis of cis and trans-fused 3a-aryloctahydroindoles using cyclization of N-vinylic α-(methylthio)acetamides: synthesis of (-)-mesembrane

金沢大学大学院自然科学研究科生理活性物質科学金沢大学薬学部Treatment of N-(2-arylcyclohex-1-en-1-yl)-α-(methylthio)acetamides with N-chlorosuccinimide (NCS) gave 3a-aryl-2,3,3a,4,5,6-hexahydro-3-(methylthio)indol-2-ones. Desulfurization of the cyclization products followed by a catalytic hydrogenation of the resulting hexahydroindol-2-ones gave predominantly or exclusively trans-fused octahydroindol-2-ones. On the other hand, reduction of the desulfurization products with Et3SiH in CF3CO2H exclusively provided cis-fused octahydroindol-2-ones. A chiral induction of N-[2-(3,4-dimethoxy)phenylcyclohex-1-en-1-yl]-α-(methylthio)acetamide having an (R)-1-(1-naphthyl)ethyl group on the nitrogen atom led to the synthesis of (-)-mesembrane and (-)-trans-mesembrane. © 2007 Elsevier Ltd. All rights reserved