155 research outputs found
Fabrication of Modified Random Phase Masks with Phase Modulation Elements Exhibiting Gaussian Profiles Using Molecular Migration under Photopolymerization
Random phase masks are important technical elements for realizing holographic memory systems that enable high density recording. However, the broadly distributed Fourier spectrum often presents a problem because wide recording spots result in reduced total storage capacity for a recording medium. In the present study, we propose modified random phase masks with phase modulation elements exhibiting Gaussian profiles to suppress the spread of the recording spot and keep it in a narrow area, based on the reduction of the high-frequency components in a random phase pattern. We confirm the effectiveness of the proposed random phase mask using simulations of a computer-generated binary hologram. However, issues still remain in terms of the fabrication of random phase masks with Gaussian profiles. Therefore, we evaluate the feasibility of fabricating the proposed random phase mask using molecular diffusion under photopolymerization. The results confirm the feasibility of this approach over a relatively wide area for actual fabrication
Ultrafast melting of charge-density wave fluctuations at room temperature in monitored under non-equilibrium conditions
We investigate the ultrafast lattice dynamics in using
femtosecond reflection pump-probe and pump-pump-probe techniques at room
temperature. The time-domain signals and Fourier-transformed spectra show the
phonon mode at 5.9 THz. Moreover, we observe an additional mode at
3 THz, corresponding to the charge-density wave (CDW) amplitude mode,
which is generally visible below TK. We argue that the
emergence of the CDW amplitude mode at room temperature can be a consequence of
fluctuations of order parameters, based on the additional experiment using the
pump-pump-probe technique, which exhibited suppression of the AM signal within
the ultrafast time scale of 0.5 ps.Comment: 15 pages, 3 figures, Applied Physics Letters, in pres
Photo-induced Tellurium segregation in
We report on the coherent phonon spectroscopy of polymorphic
single crystals using a femtosecond-pulsed laser to
investigate the relationship between structural phase transitions and
photo-thermal effects induced by high-density laser excitation. Even when a
femtosecond pulsed laser was used, which generally induces fewer heat
accumulation effects than the case for a CW laser, tellurium segregation was
observed in coherent phonon spectra with increasing excitation density, while
no structural phase transition among polymorphs of was
observed. The use of higher photon-energy excitation, however, was found to
suppress tellurium segregation.Comment: 15 pages, 4 figures, accepted for Physica Status Solidi (RRL) - Rapid
Research Letter
Terahertz emission from transient currents and coherent phonons in layered MoSe and WSe
Terahertz (THz) time-domain emission spectroscopy was performed on layered
2H-MoSe2 and 2H-WSe2. The THz emission shows an initial cycle attributed to
surge currents and is followed by oscillations attributed to coherent
interlayer phonon modes. To obtain the frequencies of the interlayer
vibrations, analysis of the THz emission waveforms were performed, separating
the two contributions to the total waveform. Results of the fitting show
several vibrational modes in the range of 5.87 to 32.75 cm-1 for the samples,
attributed to infrared-active interlayer shear and breathing modes. This study
demonstrates that THz emission spectroscopy provides a means of observing these
low frequency vibrational modes in layered materials
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The role of maternal-specific H3K9me3 modification in establishing imprinted X-chromosome inactivation and embryogenesis in mice
Maintaining a single active X-chromosome by repressing Xist is crucial for embryonic development in mice. Although the Xist activator RNF12/RLIM is present as a maternal factor, maternal Xist (Xm-Xist) is repressed during preimplantation phases to establish imprinted X-chromosome inactivation (XCI). Here we show, using a highly reproducible chromatin immunoprecipitation method that facilitates chromatin analysis of preimplantation embryos, that H3K9me3 is enriched at the Xist promoter region, preventing Xm-Xist activation by RNF12. The high levels of H3K9me3 at the Xist promoter region are lost in embryonic stem (ES) cells, and ES-cloned embryos show RNF12-dependent Xist expression. Moreover, lack of Xm-XCI in the trophectoderm, rather than loss of paternally expressed imprinted genes, is the primary cause of embryonic lethality in 70–80% of parthenogenotes immediately after implantation. This study reveals that H3K9me3 is involved in the imprinting that silences Xm-Xist. Our findings highlight the role of maternal-specific H3K9me3 modification in embryo development
TECTA mutations in Japanese with mid-frequency hearing loss affected by zona pellucida domain protein secretion
信州大学博士(医学)・学位論文・平成24年7月3日授与(乙第1146号)・茂木英明TECTA gene encodes alpha-tectorin, the major component of noncollagenous glycoprotein of the tectorial membrane, and has a role in intracochlear sound transmission. The TECTA mutations are one of the most frequent causes of autosomal dominant (AD) hearing loss and genotype-phenotype correlations are associated with mutations of TECTA in exons according to alpha-tectorin domains. In this study, we investigated the prevalence of hearing loss caused by TECTA mutations in Japanese AD hearing loss families, and confirmed genotype-phenotype correlation, as well as the intracellular localization of missense mutations in the alpha-tectorin domain. TECTA mutations were detected in 2.9% (4/139) of our Japanese AD hearing loss families, with the prevalence in moderate hearing loss being 7.7% (4/52), and all patients showed typical genotype-phenotype correlations as previously described. The present in vitro study showed differences of localization patterns between wild type and mutants, and suggested that each missense mutation may lead to a lack of assembly of secretion, and may reduce the incorporation of alpha-tectorin into the tectorial membrane. Journal of Human Genetics (2012) 57, 587-592; doi:10.1038/jhg.2012.73; published online 21 June 2012ArticleJOURNAL OF HUMAN GENETICS. 57(9):587-592 (2012)journal articl
Pressure-Wire-Guided Percutaneous Transluminal Pulmonary Angioplasty A Breakthrough in Catheter-Interventional Therapy for Chronic Thromboembolic Pulmonary Hypertension
AbstractObjectivesThis study sought to prove the safety and effectiveness of pressure-wire-guided percutaneous transluminal pulmonary angioplasty (PTPA).BackgroundPTPA has been demonstrated to be effective for treatment of chronic thromboembolic pulmonary hypertension. However, a major and occasionally fatal complication after PTPA is reperfusion pulmonary edema. To avoid this, we developed the PEPSI (Pulmonary Edema Predictive Scoring Index). The pressure wire has been used to detect insufficiency of flow in a vessel.MethodsWe included 350 consecutive PTPA sessions in 103 patients with chronic thromboembolic pulmonary hypertension from January 1, 2009 to December 31, 2013. During these 5 years, 140 PTPA sessions were performed without guidance, 65 with guidance of PEPSI alone, and 145 with both PEPSI and pressure-wire guidance. Each PTPA session was finished after achieving PEPSI scores of <35.4 with PEPSI guidance and each target lesion achieving distal mean pulmonary arterial pressure <35 mm Hg with pressure-wire guidance.ResultsThe occurrence of clinically critical reperfusion pulmonary edema and vessel injuries were lowest in the group using the guidance of both pressure wire and PEPSI (0% and 6.9%, respectively). Furthermore, the group guided by pressure wire and PEPSI accomplished the same hemodynamic improvements with fewer numbers of target lesions treated and sessions performed.ConclusionsThe combined approach using pressure wire and PEPSI produced more efficient clinical results and greatly reduced reperfusion pulmonary edema and vessel complications. This is further evidence that PTPA is an alternative strategy for treating chronic thromboembolic pulmonary hypertension
Late-stage divergent synthesis and antifouling activity of geraniol-butenolide hybrid molecules
Hybrid molecules consisting of geraniol and butenolide were designed and synthesized by the late-stage divergent strategy. In the synthetic route, ring-closing metathesis was utilized for the construction of a butenolide moiety. A biological evaluation of the eight synthetic hybrid compounds revealed that these molecules exhibit antifouling activity against the cypris larvae of the barnacle Balanus (Amphibalanus) amphitrite with EC50 values of 0.30-1.31 μg mL-1. These results show that hybridization of the geraniol and butenolide structural motifs resulted in the enhancement of the antifouling activity
Spin-gap formation due to spin-Peierls instability in π-orbital-ordered NaO2
We have investigated the low-temperature magnetism of sodium superoxide (NaO2), in which spin, orbital, and lattice degrees of freedom are closely entangled. The magnetic susceptibility shows anomalies at T1 = 220 K and T2 = 190 K, which correspond well to the structural phase transition temperatures, and a sudden decrease below T3 = 34 K. At 4.2 K, the magnetization shows a clear stepwise anomaly around 30 T with a large hysteresis. In addition, the muon spin relaxation experiments indicate no magnetic phase transition down to T = 0.3 K. The inelastic neutron scattering spectrum exhibits magnetic excitation with a finite energy gap. These results confirm that the ground state of NaO2 is a spin-singlet state. To understand this ground state in NaO2, we performed Raman scattering experiments. All the Raman-active libration modes expected for the marcasite phase below T2 are observed. Furthermore, we find that several new peaks appear below T3. This directly evidences the low crystal symmetry, namely, the presence of the phase transition at T3.We conclude that the singlet ground state of NaO2 is due to the spin-Peierls instability
Targeted single-cell gene induction by optimizing the dually regulated CRE/loxP system by a newly defined heat-shock promoter and the steroid hormone in Arabidopsis thaliana
Multicellular organisms rely on intercellular communication systems to organize their cellular functions. In studies focusing on intercellular communication, the key experimental techniques include the generation of chimeric tissue using transgenic DNA recombination systems represented by the CRE/loxP system. If an experimental system enables the induction of chimeras at highly targeted cell(s), it will facilitate the reproducibility and precision of experiments. However, multiple technical limitations have made this challenging. The stochastic nature of DNA recombination events, especially, hampers reproducible generation of intended chimeric patterns. Infrared laser-evoked gene operator (IR-LEGO), a microscopic system that irradiates targeted cells using an IR laser, can induce heat shock-mediated expression of transgenes, for example, CRE recombinase gene, in the cells. In this study, we developed a method that induces CRE/loxP recombination in the target cell(s) of plant roots and leaves in a highly specific manner. We combined IR-LEGO, an improved heat-shock-specific promoter, and dexamethasone-dependent regulation of CRE. The optimal IR-laser power and irradiation duration were estimated via exhaustive irradiation trials and subsequent statistical modeling. Under optimized conditions, CRE/loxP recombination was efficiently induced without cellular damage. We also found that the induction efficiency varied among tissue types and cellular sizes. The developed method offers an experimental system to generate a precisely designed chimeric tissue, and thus, will be useful for analyzing intercellular communication at high resolution in roots and leaves
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