Prof. Uma Maheswari Rajagopalan Profile

Prof. Uma Maheswari Rajagopalan

at Shibaura Institute of Technology

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Publications (3)

Proceedings Article | 20 June 2024 Presentation + Paper

Fast and reliable micro bioassay techniques based on biospeckle for swift water assessment using plankton

Arti Devi, Hirofumi Kadono, Uma Maheswari Rajagopalan

Proceedings Volume 13008, 1300804 (2024) https://doi.org/10.1117/12.3022436

KEYWORDS: Microorganisms, Iron, Zinc, Toxicity, Biospeckle, Control systems, Metals, Tolerancing, Organisms, Imaging systems

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Proceedings Article | 18 June 2024 Presentation + Paper

Biospeckle optical coherence tomography (bOCT) reveals the size-dependent impacts of micro and nano metal oxide particles on lentil seed’s internal activity

Lavista Tyagi, Hirofumi Kadono, Uma Maheswari Rajagopalan

Proceedings Volume 13010, 130100T (2024) https://doi.org/10.1117/12.3022190

KEYWORDS: Zinc oxide, Optical coherence tomography, Biospeckle, Particles, Nanoparticles, Metal oxides, Nanomaterials, Zinc, Industry, Computed tomography

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Nanoparticles (NPs) have become more prevalent in the agricultural, industrial, and medicinal fields. There is rising interest in how nanomaterials interact with plants since they influence plants and seeds differently depending on their size, shape, and dose. The techniques to monitor the response of plants to NPs are crucial since the effects of nanomaterials on seed germination and plant growth are uncertain. In this study, a highly sensitive, real-time, non-invasive novel technique called Biospeckle optical coherence tomography (bOCT) is used to examine the size-dependent impact of metal oxides NPs and microparticles (MPs) like Zinc Oxide (ZnO) with a size less than 50 nm, and 45μm and Titanium dioxide (TiO₂) with a size 21 nm and <5μm at concentrations of 25mg/L and 100mg/L on the internal activity of lentil seeds before germination. The results showed that ZnO NPs had an adverse effect at both higher and lower concentrations on the internal activity of lentil seeds, while MPs of 45μm had significantly positive effects even with higher concentrations. However, TiO₂ MPs and NPs showed a significant positive effect on Lentil seed’s internal activity at both concentrations in comparison to control. The proposed method was able to detect the response of Lentil seed’s internal activities to different concentrations and sizes of metal oxides NPs and MPs at an early stage just after 5 hours of exposure before the germination. On the other hand, the conventional physiological methods required a week for the effects to be detected, and the results from bOCT after 5 hours were consistent with those obtained by conventional measures. Because of the non-invasive nature of bOCT, requiring only tens of seconds of measurement with an intact. Furthermore, the technique is capable of monitoring internal biological activities while the conventional OCT monitors just structural images. It has not only the potential to screen but could also constantly monitor long-term changes, thus contributing to the study of the effects of nanomaterials on plants.

Proceedings Article | 9 March 2023 Poster + Paper

Noise reduction in LED light source-based photoacoustic imaging using M-sequences coding

Keisuke Fukuda, Kazuma Hashimoto, Uma Maheswari Rajagopalan, Takahiro Kono, Jun Yamada

Proceedings Volume 12379, 123791J (2023) https://doi.org/10.1117/12.2649032

KEYWORDS: Light emitting diodes, Signal to noise ratio, Photoacoustic spectroscopy, Photoacoustic imaging, Pulse signals, Signal processing, Laser systems engineering, Autocorrelation

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