4 research outputs found
Assessing heart rate and blood pressure estimation from image photoplethysmography using a digital blood pressure meter
No full textThis study presents a non-contact approach to measuring heart rate and blood pressure using an image photoplethysmography (iPPG) signal, and compares the results to those from an oscillometric blood pressure meter. Facial videos of 100 subjects were recorded via a webcam under ambient lighting conditions to extract iPPG signals. The results revealed a strong correlation between the heart rate derived from iPPG and that obtained from an oscillometric blood pressure meter. In addition, a continuous wavelet transform images with a 6-s duration were used as input for a custom convolutional neural network model, providing the most accurate blood pressure estimation. The proposed method received a grade A for diastolic and grade B for systolic blood pressure based on the British Hypertension Society's criteria. It also met the standards set by the Association for the Advancement of Medical Instrumentation. This non-contact framework shows promising potential for efficient screening purposes
Standard Identification Certificate for Legal Legislation of a Unique Gene Pool of Thai Domestic Elephants Originating from a Male Elephant Contribution to Breeding
No full textIllegal wildlife trade is a major threat to global biodiversity. Asian elephants (Elephas maximus) are highly valued by various cultures as religious symbols and tourist attractions, which has led to a high demand for captive elephants. Owing to the unviability of captive breeding programs, several captive elephant populations are maintained by illegally obtaining wild Asian elephants. Morbidity and mortality rates among captive populations are high, whereas reproduction is low. In this study, we examined the genetic diversity among elephants using microsatellite genotyping and mitochondrial D-loop sequences of three captive elephant populations. The study results showed very low nucleotide diversity D-loop sequences and high variations in microsatellite genotyping, with an extensive variation of the gene pool estimates from different populations. This suggests that the optimal male selection during breeding could aid in maintaining the genetic diversity among captive populations. Forward genetic simulation revealed a decreasing genetic diversity in the fixed state within 50 generations. However, largely different gene pools can be effectively used to infer original elephant sources; this would facilitate the development of an identification certificate integration with machine learning and image processing to prevent illegal legislation owing to registration fraud between wild and domestic elephants. Implementing the proposed approaches and recommendations would aid in the mitigation of the illegal capture and domestic trade of wild elephants in Thailand and contribute to the success of future conservation plans in the blueprint of sustainable development goals
Front-light Structure with Excitation Light Polarized for Enhancing Lensless Fluorescence Imaging
No full textIn this study, we introduce a high-performance front-light structure integrated with optical polarization control to improve low-contrast fluorescent imaging in lensless devices. Lensless fluorescence imaging is an advanced technology with the potential to enhance the performance of biological and neurological imaging. However, there are still challenges to achieving high image quality, particularly in low-contrast fluorescent signals due to light scattering and absorption. The performance of a low-fluorescence stripe diffractor, fabricated using Norland Optical Adhesive 63 (NOA 63), was evaluated in comparison to polydimethylsiloxane (PDMS) material as a light guide. The diffractor is designed to operate with a hybrid emission filter on the image sensor. As a result, by coupling a 450 nm laser with either P- or S-polarization, it was shown that NOA 63 is notable as a diffractor material. Notably, S-polarized light showed a great excitation intensity and an enhanced contrast in fluorescent bead imaging compared with P-polarized light. Furthermore, the system was validated for biological applications by successfully detecting fluorescent bead emission in agarose-embedded samples of various thicknesses, simulating brain tissue. These results emphasize the system’s ability to capture lowintensity fluorescence signals from deep layers of biological tissue.journal articl
