Nearshore Bathymetry Estimation from Drone Video Using PIV Technique

This research introduces a novel method to estimate nearshore bottom topography using an unmanned aerial vehicle (UAV), or drone. The UAV was manipulated over the area of interest to film video, and the Particle image velocimetry (PIV) technique was then applied to analyze the video frames in order to retrieve the wave speeds. Under the shallow water conditions, the wave dispersion relation can be simplified in a manner such that when the wave speed is known, the water depth can be inferred. In other words, when wave speed is known, water depth can be inferred. After combining the inferred water depths at multiple points from within the area of interest, the bathymetry was constructed. To validate the method, individual waves were recorded in the nearshore breaking zone during two trials at Freeport, Texas, USA. We measured the significant difference in intensity across the recorded images, as the intensity had a larger signal-to-noise ratio, and this improved the implementation of the PIV algorithm. We then compared the PIVestimated water depth with field measurement and observations, finding that the water depth was overestimated by 13.5%, which was primarily explained by non-linear wave breaking effects. We then introduced a correction factor, reducing the estimation error to within 6% of the true observed water depth. Though there are limitations, this new approach can lower the cost of developing bathymetric maps in the nearshore and result in greater flexibility across space and time. Further improvements in equipment and work on developing better correction factors may result in still greater precision

Piezoelectric cantilever sensors

A piezoelectric cantilever with a non-piezoelectric, or piezoelectric tip useful as mass and viscosity sensors. The change in the cantilever mass can be accurately quantified by monitoring a resonance frequency shift of the cantilever. For bio-detection, antibodies or other specific receptors of target antigens may be immobilized on the cantilever surface, preferably on the non-piezoelectric tip. For chemical detection, high surface-area selective absorbent materials are coated on the cantilever tip. Binding of the target antigens or analytes to the cantilever surface increases the cantilever mass. Detection of target antigens or analytes is achieved by monitoring the cantilever's resonance frequency and determining the resonance frequency shift that is due to the mass of the adsorbed target antigens on the cantilever surface. The use of a piezoelectric unimorph cantilever allows both electrical actuation and electrical sensing. Incorporating a non-piezoelectric tip (14) enhances the sensitivity of the sensor. In addition, the piezoelectric cantilever can withstand damping in highly viscous liquids and can be used as a viscosity sensor in wide viscosity range

Nearshore Bathymetry Estimation from Drone Video Using PIV Technique

This research introduces a novel method to estimate nearshore bottom topography using an unmanned aerial vehicle (UAV), or drone. The UAV was manipulated over the area of interest to film video, and the Particle image velocimetry (PIV) technique was then applied to analyze the video frames in order to retrieve the wave speeds. Under the shallow water conditions, the wave dispersion relation can be simplified in a manner such that when the wave speed is known, the water depth can be inferred. In other words, when wave speed is known, water depth can be inferred. After combining the inferred water depths at multiple points from within the area of interest, the bathymetry was constructed. To validate the method, individual waves were recorded in the nearshore breaking zone during two trials at Freeport, Texas, USA. We measured the significant difference in intensity across the recorded images, as the intensity had a larger signal-to-noise ratio, and this improved the implementation of the PIV algorithm. We then compared the PIVestimated water depth with field measurement and observations, finding that the water depth was overestimated by 13.5%, which was primarily explained by non-linear wave breaking effects. We then introduced a correction factor, reducing the estimation error to within 6% of the true observed water depth. Though there are limitations, this new approach can lower the cost of developing bathymetric maps in the nearshore and result in greater flexibility across space and time. Further improvements in equipment and work on developing better correction factors may result in still greater precision

Critical role of the Mac1/NOX2 pathway in mediating reactive microgliosis-generated chronic neuroinflammation and progressive neurodegeneration

As average life expectancy rises throughout the world, neurodegenerative diseases have emerged as one of the greatest global public heath challenges in modern times. Substantial efforts have been made in researching neurodegenerative diseases over the last few decades, yet their predominantly sporadic nature has made uncovering their etiologies challenging. Mounting evidence has suggested that factors like damage-associated molecular patterns (DAMPs) released by stressed and dying neurons are likely involved in disease pathology and in stimulating chronic activation of microglia that contributes to neuronal oxidative stress and degeneration. This review focuses on how the microglial integrin receptor Mac1 and its downstream effector NADPH oxidase (NOX2) contribute to maintaining chronic neuroinflammation and are crucial in inflammation-driven neurotoxicity in neurodegenerative diseases. Our hope is to provide new insights on novel targets and therapies that could slow or even halt neurodegeneration

Spermatic Cord Metastasis of Primary Hepatocellular Carcinoma Presenting as an Inguinal Mass: A Case Report

Most spermatic cord masses are benign, and malignant spermatic cord tumors are uncommon. Spermatic cord metastases originating from hepatocellular carcinoma (HCC) have not been previously reported in the English language literature as determined by a PubMed search. We report a male patient who presented with a painful palpable mass in the right inguinal area. The patient was diagnosed with HCC in 2004 and undertook a nonsurgical approach to control the cancer. A radical orchiectomy was performed, and the pathological report showed metastatic HCC in the spermatic cord. The patient received palliative radiation therapy because of a positive surgical margin. No recurrence was noted after 6 months of followup