We describe a side by side comparison between spectroscopy and pulse oximetry measurements done on skin to measure blood oxygen levels, highlighting the importance of using broader wavelength measurements to capture the impact of skin pigmentation on the accuracy of oximetry.
KEYWORDS: Object detection, Portability, Microscopes, Microscopy, Education and training, Medicine, Diseases and disorders, Detection and tracking algorithms, Cameras, 3D printing
Helminth infections affect around 1.5 billion people worldwide but have historically been neglected by major healthcare initiatives. Manual microscopic examination to identify parasite eggs in urine or faeces remains the gold-standard diagnostic, but the technique is time consuming and requires bright-field microscopes which can be expensive to transport and maintain. We present a low-cost device which uses deep learning to automate helminth diagnosis from Kato-Katz (KK) faecal smears. The device comprises a 3D-printed microscope, which connects wirelessly to an Android smartphone. Egg detection is accomplished with a ResNet-50 object detection algorithm, trained on a dataset of over 6,000 images of eggs from six common helminth species. The model is exported to TensorFlow Lite and hosted locally in the app, enabling edge computing and removing the need for external internet connection.
We are exploring the use of different optical regions in the Mid-infrared (Mid-IR) that can be used to develop future point
of care tools and methodologies. This research will allow us to establish new methods to monitor proxies for health within
blood samples. Mid-IR spectra of heme groups were studied by FTIR analysis to find spectral signatures can be exploited
to quantify the redox state of haemoglobin as a function of its concentration. We performed Attenuated Total Reflection
Spectroscopy (ATR) using heme groups. We found spectral differences between HbMet and Hb/HbO2 in the regions
3000-3600, 2000-2100 and 1300 cm-1. Mid-IR has the potential to expand the optical tools in medical monitoring and
diagnosis for future non-invasive characterization systems. This could open a window of opportunity to understand proxies
for disease and health in blood.
We describe a visible-light multi-spectral system for vascular oximetry studies that can be implemented in lowand middle-income countries, using a low-cost electronics and optical elements, for instance a Raspberry Pi, a Pi camera under a resolution of 5-megapixel, 2592x1944-pixel resolution, and four different light sources at 480nm, 532nm, 593nm and 610nm on a singular structured illumination area. It is designed to quantify the vascular oxygen saturation change of the rat dorsal spinal cord, which uses a Phyton custom application that synchronize all elements to execute the imaging process in one system, powered by a portable rechargeable 5V battery pack. Aimed for drug discovery, tracking disease progression and understanding of progressive and degenerative diseases. By replacing expensive and bulky imaging systems.
In this paper we show how the electrical lysis of cells can be controlled through the use of an optoelectronic device and describe how the lysis is affected by the size and shape of the cell as well as the geometry of the device and the light patterns used. By selectively illuminating a photoconductor “virtual electrodes” are created allowing the precise control of electrical fields onto the cell within the device, electrically rupturing their membranes and allowing access to intracellular contents. We examine this optically controlled electrical lysis method and discuss its advantages as a sample preparation technique.
Infectious diseases cause 10 million deaths each year worldwide, accounting for ~60% of all deaths of children aged 5-
14. Although these deaths arise primarily through pneumonia, TB, malaria and HIV, there are also the so called
"neglected diseases" such as sleeping sickness and bilharzia, which have a devastating impact on rural communities, in
sub-Sahara Africa. There, the demands for a successful Developing World diagnostic are particularly rigorous, requiring
low cost instrumentation with low power consumption (there is often no fixed power infrastructure). In many cases, the
levels of infection within individuals are also sufficiently low that instruments must show extraordinary sensitivity, with
measurements being made in blood or saliva. In this talk, a description of these demands will be given, together with a
review of some of the solutions that have been developed, which include using acoustics, optics and electrotechnologies,
and their combinations to manipulate the fluid samples. In one example, we show how to find a single trypanosome, as
the causative agent of sleeping sickness.
Microfluidic systems have faced challenges in handling real samples and the chip interconnection to other instruments.
Here we present a simple interface, where surface acoustic waves (SAWs) from a piezoelectric device are coupled into a
disposable acoustically responsive microfluidic chip. By manipulating droplets, SAW technologies have already shown
their potential in microfluidics, but it has been limited by the need to rely upon mixed signal generation at multiple
interdigitated electrode transducers (IDTs) and the problematic resulting reflections, to allow complex fluid operations.
Here, a silicon chip was patterned with phononic structures, engineering the acoustic field by using a full band-gap. It
was simply coupled to a piezoelectric LiNbO3 wafer, propagating the SAW, via a thin film of water. Contrary to the use
of unstructured superstrates, phononic metamaterials allowed precise spatial control of the acoustic energy and hence its
interaction with the liquids placed on the surface of the chip, as demonstrated by simulations. We further show that the
acoustic frequency influences the interaction between the SAW and the phononic lattice, providing a route to programme
complex fluidic manipulation onto the disposable chip. The centrifugation of cells from a blood sample is presented as a
more practical demonstration of the potential of phononic crystals to realize diagnostic systems.
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