60 research outputs found
Standalone gradient measurement of matrix norm for programmable unitary converters
Programmable unitary converters are powerful tools for realizing unitary
transformations, advancing fields of computing and communication. The accuracy
of these unitary transformations is crucial for maintaining high fidelity in
such applications. However, various physical artifacts can impair the accuracy
of the synthesized transformations. A commonly employed approach uses the
system's gradient to restore accuracy. Although this gradient can indeed be
physically measured using external equipment, it leads to a rather complex
optical system. In this study, we propose a standalone method for measuring
matrix norm gradients, where 'standalone' means that no additional optical
equipment is needed. This method is based on the mathematical fact that the
central difference, which is generally used for the approximation of
differentiation, can yield exact differentiation for any unitary transformer.
Furthermore, we introduce a new matrix distance that is suitable for optimizing
unitary converters which use intensity detectors at the output. Numerical
analysis demonstrates that our method exhibits orders of magnitude higher
tolerance to measurement noise than prior similar approaches.Comment: Submitted to Optics Letter
Analysis and experimental assessment of the sensitivity of stimulated Raman scattering microscopy
Ozeki Y., Dake F., Kajiyama S., et al. Analysis and experimental assessment of the sensitivity of stimulated Raman scattering microscopy. Optics Express, 17, 5, 3651. https://doi.org/10.1364/OE.17.003651
光ファイバ増幅器を用いた光スペクトル広帯域化技術に関する研究
University of Tokyo (東京大学
Deuterium- and Alkyne-Based Bioorthogonal Raman Probes for In Situ Quantitative Metabolic Imaging of Lipids within Plants
Plants can rapidly respond to different stresses by activating multiple signaling and defense pathways. The ability to directly visualize and quantify these pathways in real time using bioorthogonal probes would have practical applications, including characterizing plant responses to both abiotic and biotic stress. Fluorescence-based labels are widely used for tagging of small biomolecules but are relatively bulky and with potential effects on their endogenous localization and metabolism. This work describes the use of deuterium- and alkyne-derived fatty acid Raman probes to visualize and track the real-time response of plants to abiotic stress within the roots. Relative quantification of the respective signals could be used to track their localization and overall real-time responses in their fatty acid pools due to drought and heat stress without labor-intensive isolation procedures. Their overall usability and low toxicity suggest that Raman probes have great untapped potential in the field of plant bioengineering
Highly sensitive spectral interferometric fourwave mixing microscopy near the shot noise limit and its combination with two-photon excited fluorescence microscopy
Isobe K., Ozeki Y., Kawasumi T., et al. Highly sensitive spectral interferometric fourwave mixing microscopy near the shot noise limit and its combination with two-photon excited fluorescence microscopy. Optics Express, 14, 23, 11204. https://doi.org/10.1364/OE.14.011204
Engineered Mutants of a Marine Photosynthetic Purple Nonsulfur Bacterium with Increased Volumetric Productivity of Polyhydroxyalkanoate Bioplastics
Polyhydroxyalkanoates (PHAs) are green and sustainable bioplastics that could replace petrochemical synthetic plastics without posing environmental threats to living organisms. In addition, sustainable PHA production could be achieved using marine photosynthetic purple nonsulfur bacteria (PNSBs) that utilize natural seawater, sunlight, carbon dioxide gas, and nitrogen gas for growth. However, PHA production using marine photosynthetic PNSBs has not been economically feasible yet due to its high cost and low productivity. In this work, strain improvement, using genome-wide mutagenesis coupled with high-throughput screening via fluorescence-activated cell sorting, we were able to create Rhodovulum sulfidophilum mutants with enhanced volumetric PHA productivity, with an up to 1.7-fold increase. The best selected mutants (E6 and E6M4) reached the stationary growth phase 1 day faster and accumulated the maximum PHA content 2 days faster than the wild type. Maximizing volumetric PHA productivity before the stationary growth phase is indeed an additional advantage for R. sulfidophilum as a growth-associated PHA producer
Significantly low level of small RNA accumulation derived from an encapsidated mycovirus with dsRNA genome
AbstractThe role of RNA silencing as an antiviral defence has been well elucidated in plants and invertebrates, but not in filamentous fungi. We have previously determined the complete genome sequence of Magnaporthe oryzae virus 2 (MoV2), a dsRNA virus that infects the rice blast fungus Magnaporthe oryzae. In this study, we detected small interfering RNAs (siRNAs) from both positive- and negative-strand MoV2 viral RNA, suggesting that the RNA silencing machinery in M. oryzae functions against the mycovirus. Cloning and characterisation of MoV2 siRNAs indicated that, in MoV2, the ratio of virus-derived siRNAs to total small RNA is significantly lower than that in either plant viruses or Cryphonectria hypovirus 1 (CHV1), another mycovirus. Nevertheless, any MoV2-encoded proteins did not exhibit RNA silencing suppressor activity in both the plant and fungal systems. Our study suggests the existence of a novel viral strategy employed to evade host RNA silencing
Stimulated raman scattering microscope with shot noise limited sensitivity using subharmonically synchronized laser pulses
Ozeki Y., Kitagawa Y., Sumimura K., et al. Stimulated raman scattering microscope with shot noise limited sensitivity using subharmonically synchronized laser pulses. Optics Express, 18, 13, 13708. https://doi.org/10.1364/OE.18.013708
Label-free imaging by stimulated parametric emission microscopy reveals a difference in hemoglobin distribution between live and fixed erythrocytes
Hieu M. Dang, Gen Omura, Toshiyuki Omano, Masatomo Yamagiwa, Shin'ichiro Kajiyama, Yasuyuki Ozeki, Kazuyoshi Itoh, and Kiichi Fukui "Label-free imaging by stimulated parametric emission microscopy reveals a difference in hemoglobin distribution between live and fixed erythrocytes," Journal of Biomedical Optics 14(4), 040506 (1 July 2009). https://doi.org/10.1117/1.320715
Label-free observation of tissues by high-speed stimulated Raman spectral microscopy and independent component analysis
SPIE BiOS, 2013, San Francisco, California, United StatesYasuyuki Ozeki, Yoichi Otsuka, Shuya Sato, Hiroyuki Hashimoto, Wataru Umemura, Kazuhiko Sumimura, Norihiko Nishizawa, Kiichi Fukui, Kazuyoshi Itoh, "Label-free observation of tissues by high-speed stimulated Raman spectral microscopy and independent component analysis," Proc. SPIE 8588, Multiphoton Microscopy in the Biomedical Sciences XIII, 858806 (22 February 2013); https://doi.org/10.1117/12.200277
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