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Positronium is an ideal system for research on Quantum Electrodynamics (QED), especially in a bound state. A discrepancy of 3.9 standard deviations has been found between the measured hyperfine structure (Ps-HFS) and the QED predictions. This may be due to the contribution of unknown new physics or common systematic effects in previous measurements, in all of which the Zeeman effect was used. We propose a new method to directly measure the Ps-HFS using a high power gyrotron. We compare two resonators which have been developed to supply sufficient power to drive the direct transition, a Fabry-Pérot resonator and a ring resonator with a diffraction grating. We plan to perform first direct measurement of Ps-HFS within the next six months. [ABSTRACT FROM AUTHOR]

Positronium is an ideal system for the research of the bound state QED. The hyperfine splitting of positronium (Ps-HFS, about 203 GHz) is an important observable but all previous measurements of Ps-HFS had been measured indirectly using Zeeman splitting. There might be the unknown systematic errors on the uniformity of magnetic field. We are trying to measure Ps-HFS directly using sub-THz radiation. We developed an optical system to accumulate high power (about 10 kW) radiation in a Fabry-Pérot resonant cavity and observed the positronium hyperfine transition for the first time. [ABSTRACT FROM AUTHOR]

Positronium is an ideal system for research on QED, especially in a bound state. A discrepancy (3.9 σ) is found recently between measured HFS values and the QED prediction (including up-to O( α log α), where α is the fine-structure constant.). It might be due to a contribution of unknown new physics or common systematic problems in all the previous measurements. A new method to measure HFS directly is performed using a high power gyrotron. The transition from ortho-positronium to para-positronium has been observed with 5 σ CL, which is the first observation of M1 transition in (sub)Terahertz region. New technologies of high power gyrotrons are developed for precision spectroscopy. [ABSTRACT FROM AUTHOR]

An optimal design method for stable IIR (Infinite Impulse Response) filters under the min-max criterion is proposed. The design problem considered is the complex Chebyshev approximation of a rational function including the stability constraint. We formulate this problem as a problem of real linear semi-infinite programming problem using the real rotation theorem. The problem is solved by the three-phase method; one of the methods is used for solving semi-infinite programming problems. The three-phase method includes three operations. In the first operation, some active constraint candidates are selected by the iterative simplex method. Next, the second operation integrates some degenerate constraints. In the third operation, the approximate solution obtained up to the second operation is adjusted so as to satisfy the optimality condition. The filters designed by the method are found to be more precise than those designed by the conventional method. Several design examples are presented to demonstrate the effectiveness of the proposed method. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(6): 17-23, 2011; Published online in Wiley Online Library (). DOI 10.1002/ecj.10330 [ABSTRACT FROM AUTHOR]

This paper proposes a new circuit topology of the three-phase soft-switching PWM inverter and PFC converter using IGBT power modules, which has the improved active auxiliary switch and edge resonant bridge leg-commutation-link soft-switching snubber circuit with pulse current regenerative feedback loop as compared with the typical auxiliary resonant pole snubber discussed previously. This three-phase soft-switching PWM double converter is more suitable and acceptable for a large-capacity uninterruptible power supply, PFC converter, utility-interactive bidirectional converter, and so forth. In this paper, the soft-switching operation and optimum circuit design of the novel type active auxiliary edge resonant bridge leg commutation link snubber treated here are described for high-power applications. Both the main active power switches and the auxiliary active power switches achieve soft switching under the principles of ZVS or ZCS in this three-phase inverter switching. This three-phase soft-switching commutation scheme can effectively minimize the switching surge-related electromagnetic noise and the switching power losses of the power semiconductor devices; IGBTs and modules used here. This three-phase inverter and rectifier coupled double converter system does not need any sensing circuit and its peripheral logic control circuits to detect the voltage or the current and does not require any unwanted chemical electrolytic capacitor to make the neutral point of the DC power supply voltage source. The performances of this power conditioner are proved on the basis of the experimental and simulation results. Because the power semiconductor switches (IGBT module packages) have a trade-off relation in the switching fall time and tail current interval characteristics as well as the conductive saturation voltage characteristics, this three-phase soft-switching PWM double converter can improve actual efficiency in the output power ranges with a trench gate controlled MOS power semiconductor device which is much improved regarding low saturation voltage. The effectiveness of this is verified from a practical point of view. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(4): 64–76, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20207 [ABSTRACT FROM AUTHOR]

SQAG9, a new class of immunosuppressive sulfoquinovosylacylglycerol, and its biotinylated derivatives have been synthesized. A T7 Phage library, composed of random cDNA fragments from Drosophila melanogaster, displayed a possible binding peptide of 14 amino acids. The immobilized synthetic peptide on a sensor chip showed a dissociation constant of KD=1.5×10-6 against SQAG9 in a surface plasmon resonance experiment. [Copyright &y& Elsevier]

Sulfo-glycolipids in the class of sulfoquinovosyl diacylglycerol (SQDG) including the stereoisomers are potent inhibitors of DNA polymerase α and β. However, since the α-configuration of SQDG with two stearic acids (α-SQDG-C18) can hardly penetrate cells, it has no cytotoxic effect. We tried and succeeded in making a permeable form, sulfoquinovosyl monoacylglycerol with a stearic acid (α-SQMG-C18) from α-SQDG-C18 by hydrolysis with a pancreatic lipase. α-SQMG-C18 inhibited DNA polymerase activity and was found to be a potent inhibitor of the growth of NUGC-3 cancer cells. α-SQMG-C18 arrested the cell cycle at the G1 phase, and subsequently induced severe apoptosis. The arrest was correlated with an increased expression of p53 and cyclin E, indicating that α-SQMG-C18 induced cell death through a p53-dependent apoptotic pathway. [Copyright &y& Elsevier]

We reported previously that sulfo-glycolipids such as sulfoquinovosyl-diacylglycerol (SQDG) and sulfoquinovosyl-monoacylglycerol (SQMG) are potent inhibitors of DNA polymerase α and β and antineoplastic agents. Then, we succeeded in synthesizing SQDG and SQMG chemically, including their stereoisomers, glucopyranosyl-diacylglycerol (GDG) and glucopyranosyl-monoacylglycerol (GMG). In this study, we demonstrated the structure–function relationship of the synthetic sulfo-glycolipids to DNA polymerase α and β and their relationship to the cytotoxic activity. Both SQDG and SQMG inhibited the activity of mammalian DNA polymerase α with IC50 values of 3–5 μM, but GMG only moderately inhibited it. GDG, diacylglycerol (DG), and monoacylglycerol (MG) did not influence any of the DNA polymerase activities. The sulfate moiety in the quinovose was important in inhibiting the enzyme activity. The one-fatty-acid-sulfo-glycolipids, SQMG, GMG, and MG, prevented the growth of NUGC-3 human gastric cancer cells and induced apoptotic cell death, but the two-fatty-acid-sulfo-glycolipids, SQDG, GDG, and DG, did not. SQMG and GMG could halt the cell cycle at the G1 phase, but the cell cycle was not changed by MG. The relationship between the DNA polymerase inhibition and the cell growth effect by these compounds are discussed. [Copyright &y& Elsevier]

Background: Following ankle sprains, some patients complain of their ankles "giving way," characterized by functional instability with no positive findings in traditional stress tests. The calcaneofibular ligament (CFL) may contribute to the stabilization of the subtalar and talocrural joints, and some functional instability may be due to CFL insufficiency. We aimed to clarify and quantitatively assess CFL insufficiency with three-dimensional stress computer tomography (CT) using the Pronation-External Rotation Stress Test (PERST).Methods: Ten patients who tested positive under PERST and underwent an isolated CFL reconstruction were included. Using a custom-made loading jig, we used the Supination-Internal Rotation Stress Test (SIRST) and PERST to assess the function of anterior talofibular ligament (ATFL) and CFL, respectively. 3D-CT in neutral position was used as a baseline, and we quantified the distance between the origin and insertion of the CFL and ATFL at 2 years pre- and postoperatively.Results: Postoperative scores improved in all patients with no giving way symptoms. The preoperative length of the CFL increased by 14.0% from baseline under PERST, while the postoperative length only increased by 2.0% and was significantly restricted (P < .01). The pre- and postoperative length of ATFL was increased by 7.5% and 9.0% from baseline under SIRST, respectively, with no significant difference (P = .41). The clinical function improved with significantly less change in distance between the origin and insertion under PERST and showed no difference under SIRST.Conclusion: The 3D-CT stress test may be useful for quantifying pre- and postoperative CFL function. CFL insufficiency is one of the main causes of subtalar joint instability; therefore, measuring the distance between the origin and insertion of the CFL could provide the means to quantify the instability of the subtalar joint. [ABSTRACT FROM AUTHOR]

Sulfoquinovosylacylglycerols (SQAGs), in particularcompounds with C18 fatty acid(s) on the glycerol moiety, may be clinically promising antitumor and/or immunosuppressive agents. They were found originally as inhibitors of mammalian DNA polymerases. However, SQAGs can arrest cultured mammalian cells not only at S phase but also at M phase, suggesting they have several molecular targets. A screen for candidate target molecules using a T7 phage display method identified an amino acid sequence. An homology search showed this to be a mammalian mitotic centromere-associated kinesin (MCAK), rather than a DNA polymerase. Analyses showed SQAGs bound to recombinant MCAK with aKD = 3.1 × 10−4 to 6.2 × 10−5m. Anin vivomicrotubule depolymerization assay, using EGFP-full length MCAK fusion constructs, indicated inhibition of the microtubule depolymerization activity of MCAK. From these results, we conclude that clinically promising SQAGs have at least two different molecular targets, DNA polymerases and MCAK. It should be stressed that inhibitors of MCAK have never been reported previously so that there is a major potential for clinical utility. [ABSTRACT FROM AUTHOR]

Background: Inversion ankle sprains, or lateral ankle sprains, often result in symptomatic lateral ankle instability, and some patients need lateral ankle ligament reconstruction to reduce pain, improve function, and prevent subsequent injuries. Although anatomically reconstructed ligaments should behave in a biomechanically normal manner, previous studies have not measured the strain patterns of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) after anatomical reconstruction. This study aimed to measure the strain patterns of normal and reconstructed ATFL and CFLs using the miniaturization ligament performance probe (MLPP) system.Methods: The MLPP was sutured into the ligamentous bands of the ATFLs and CTLs of three freshly frozen cadaveric lower-extremity specimens. Each ankle was manually moved from 15° dorsiflexion to 30° plantar flexion, and a 1.2-N m force was applied to the ankle and subtalar joint complex.Results: The normal and reconstructed ATFLs exhibited maximal strain (100) during supination in three-dimensional motion. Although the normal ATFLs were not strained during pronation, the reconstructed ATFLs demonstrated relative strain values of 16-36. During the axial motion, the normal ATFLs started to gradually tense at 0° plantar flexion, with the strain increasing as the plantar flexion angle increased, to a maximal value (100) at 30° plantar flexion; the reconstructed ATFLs showed similar strain patterns. Further, the normal CFLs exhibited maximal strain (100) during plantar flexion-abduction and relative strain values of 30-52 during dorsiflexion in three-dimensional motion. The reconstructed CFLs exhibited the most strain during dorsiflexion-adduction and demonstrated relative strain values of 29-62 during plantar flexion-abduction. During the axial motion, the normal CFLs started to gradually tense at 20° plantar flexion and 5° dorsiflexion.Conclusion: Our results showed that the strain patterns of reconstructed ATFLs and CFLs are not similar to those of normal ATFLs and CFLs. [ABSTRACT FROM AUTHOR]

Background: Measuring the strain patterns of ligaments at various joint positions informs our understanding of their function. However, few studies have examined the biomechanical properties of ankle ligaments; further, the tensile properties of each ligament, during motion, have not been described. This limitation exists because current biomechanical sensors are too big to insert within the ankle. The present study aimed to validate a novel miniaturized ligament performance probe (MLPP) system for measuring the strain patterns of the anterior talofibular ligament (ATFL) during ankle motion.Methods: Six fresh-frozen, through-the-knee, lower extremity, cadaveric specimens were used to conduct this study. An MLPP system, comprising a commercially available strain gauge (force probe), amplifier unit, display unit, and logger, was sutured into the midsubstance of the ATFL fibers. To measure tensile forces, a round, metal disk (a "clock", 150 mm in diameter) was affixed to the plantar aspect of each foot. With a 1.2-Nm load applied to the ankle and subtalar joint complex, the ankle was manually moved from 15° dorsiflexion to 30° plantar flexion. The clock was rotated in 30° increments to measure the ATFL strain detected at each endpoint by the miniature force probe. Individual strain data were aligned with the neutral (0) position value; the maximum value was 100.Results: Throughout the motion required to shift from 15° dorsiflexion to 30° plantar flexion, the ATFL tensed near 20° (plantar flexion), and the strain increased as the plantar flexion angle increased. The ATFL was maximally tensioned at the 2 and 3 o'clock (inversion) positions (96.0 ± 5.8 and 96.3 ± 5.7) and declined sharply towards the 7 o'clock position (12.4 ± 16.8). Within the elastic range of the ATFL (the range within which it can return to its original shape and length), the tensile force was proportional to the strain, in all specimens.Conclusion: The MLPP system is capable of measuring ATFL strain patterns; thus, this system may be used to effectively determine the relationship between limb position and ATFL ankle ligament strain patterns. [ABSTRACT FROM AUTHOR]

Background: There are few reports on the detailed biomechanics of the deltoid ligament, and no studies have measured the biomechanics of each ligamentous band because of the difficulty in inserting sensors into the narrow ligaments. This study aimed to measure the strain pattern of the deltoid ligament bands directly using a Miniaturization Ligament Performance Probe (MLPP) system.Methods: The MLPP was sutured into the ligamentous bands of the deltoid ligament in 6 fresh-frozen lower extremity cadaveric specimens. The strain was measured using a round metal disk (clock) fixed on the plantar aspect of the foot. The ankle was manually moved from 15° dorsiflexion to 30° plantar flexion, and a 1.2-N-m force was applied to the ankle and subtalar joint complex. Then the clock was rotated every 30° to measure the strain of each ligamentous band at each endpoint.Results: The tibionavicular ligament (TNL) began to tense at 10° plantar flexion, and the tension becomes stronger as the angle increased; the TNL worked most effectively in plantar flex-abduction. The tibiospring ligament (TSL) began to tense gradually at 15° plantar flexion, and the tension became stronger as the angle increased. The TSL worked most effectively in abduction. The tibiocalcaneal ligament (TCL) began to tense gradually at 0° dorsiflexion, and the tension became stronger as the angle increased. The TCL worked most effectively in pronation (dorsiflexion-abduction). The superficial posterior tibiotalar ligament (SPTTL) began to tense gradually at 0° dorsiflexion, and the tension became stronger as the angle increased, with the SPTTL working most effectively in dorsiflexion.Conclusion: Our results show the biomechanical function of the superficial deltoid ligament and may contribute to determining which ligament is damaged during assessment in the clinical setting. [ABSTRACT FROM AUTHOR]

A new experiment to measure vacuum magnetic birefringence (VMB), the OVAL experiment, is reported. We developed an original pulsed magnet that has a high repetition rate and applies the strongest magnetic field among VMB experiments online. The vibration isolation design and feedback system enable the direct combination of the magnet with a Fabry-Pérot cavity. To demonstrate and benchmark the searching potential, a calibration measurement with dilute nitrogen gas and a prototype search for VMB are performed. Based on the results, a strategy to observe VMB is reported. Graphical abstract: [ABSTRACT FROM AUTHOR]

We have previously reported that sulfoquinovosylmonoacylglycerol (SQMG) is a potent inhibitor of mammalian DNA polymerases. DNA polymerase β (pol β) is one of the most important enzymes protecting the cell against DNA damage by base excision repair. In this study, we characterized the inhibitory action of SQMG against rat pol β. SQMG competed with both the substrate and the template-primer for binding to pol β. A gel mobility shift assay and a polymerase activity assay showed that SQMG competed with DNA for a binding site on the N-terminal 8-kDa domain of pol β, subsequently inhibiting its catalytic activity. Fragments of SQMG such as sulfoquinovosylglycerol (SQG) and fatty acid (myristoleic acid, MA) weakly inhibited pol β activity and the inhibitory effect of a mixture of SQG and MA was stronger than that of SQG or MA. To characterize this inhibition more precisely, we attempted to identify the interaction interface between SQMG and the 8-kDa domain by NMR chemical shift mapping. Firstly, we determined the binding site on a fragment of SQMG, the SQG moiety. We observed chemical shift changes primarily at two sites, the residues comprising the C-terminus of helix-1 and the N-terminus of helix-2, and residues in helix-4. Finally, based on our present results and our previously reported study of the interaction interface of fatty acids, we constructed two three-dimensional models of a complex between the 8-kDa domain and SQMG and evaluated them by the mutational analysis. The models show a SQMG interaction interface that is consistent with the data. [ABSTRACT FROM AUTHOR]