In this study, an optical contactless laser speckle imaging technique for the early identification of bacterial colony-forming units was tested. The aim of this work is to compare the laser speckle imaging method for the early assessment of microbial activity with standard visual inspection under white light illumination. In presented research, the growth of bacterial colonies on the solid medium was observed and analyzed. Both - visual examination under white light illumination and laser speckle correlation analysis were performed. Based on various experiments and comparisons with the theoretical Gompertz model, colony radius growth curves were obtained. It was shown that the Gompertz model can be used to describe both types of analysis. A comparison of the two methods shows that laser speckle contrast imaging, combined with signal processing, can detect colony growth earlier than standard CFU counting method under white light illumination.
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http://dx.doi.org/10.1364/BOE.416456 | DOI Listing |
Holographic light potentials generated by phase-modulating liquid-crystal spatial light modulators (SLMs) are widely used in quantum technology applications. Accurate calibration of the wavefront and intensity profile of the laser beam at the SLM display is key to the high fidelity of holographic potentials. Here, we present a new calibration technique that is faster than previous methods while maintaining the same level of accuracy.
View Article and Find Full Text PDFNeurophotonics
January 2025
University of Kentucky, Department of Biomedical Engineering, Lexington, Kentucky, United States.
Significance: Cerebral blood flow (CBF) imaging is crucial for diagnosing cerebrovascular diseases. However, existing large neuroimaging techniques with high cost, low sampling rate, and poor mobility make them unsuitable for continuous and longitudinal CBF monitoring at the bedside.
Aim: We aimed to develop a low-cost, portable, programmable scanning diffuse speckle contrast imaging (PS-DSCI) technology for fast, high-density, and depth-sensitive imaging of CBF in rodents.
Med Biol Eng Comput
January 2025
School of Biomedical Engineering, Shanghai Jiao Tong University, No.1954 Huashan Road, Shanghai, 200030, Shanghai, China.
Previous studies reported baseline state-dependent effects on neural and hemodynamic responses to transcranial ultrasound stimulation. However, due to neurovascular coupling, neither neural nor hemodynamic baseline alone can fully explain the ultrasound-induced responses. In this study, using a general linear model, we aimed to investigate the roles of both neural and hemodynamic baseline status as well as their interactions in ultrasound-induced responses.
View Article and Find Full Text PDFJ Biomed Opt
January 2025
The Johns Hopkins University, Department of Biomedical Engineering, Baltimore, Maryland, United States.
Significance: Laparoscopic surgery presents challenges in localizing oncological margins due to poor contrast between healthy and malignant tissues. Optical properties can uniquely identify various tissue types and disease states with high sensitivity and specificity, making it a promising tool for surgical guidance. Although spatial frequency domain imaging (SFDI) effectively measures quantitative optical properties, its deployment in laparoscopy is challenging due to the constrained imaging environment.
View Article and Find Full Text PDFNeurophotonics
January 2025
California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States.
Significance: Cerebral blood flow (CBF) and cerebral blood volume (CBV) are key metrics for regional cerebrovascular monitoring. Simultaneous, non-invasive measurement of CBF and CBV at different brain locations would advance cerebrovascular monitoring and pave the way for brain injury detection as current brain injury diagnostic methods are often constrained by high costs, limited sensitivity, and reliance on subjective symptom reporting.
Aim: We aim to develop a multi-channel non-invasive optical system for measuring CBF and CBV at different regions of the brain simultaneously with a cost-effective, reliable, and scalable system capable of detecting potential differences in CBF and CBV across different regions of the brain.
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