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

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

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

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

Intelligent Image-Activated Cell Sorting and Beyond

We present a groundbreaking machine intelligence technology called “intelligent image-activated cell sorting” that achieves high-throughput image-triggered sorting of single cells by integrating high-speed fluorescence microscopy, cell focusing, cell sorting, and deep learning