Atrial fibrillation (AF) is the most common arrhythmia, with a prevalence of 0.95% among the adult population. It is associated with quivering or irregular heartbeat, that can lead to blood clots, stroke, heart failure and other heart-related complications. The currently accepted convention for AF diagnosis is the presence of an episode lasting at least 30 seconds. It has been shown that further characterization of the condition over longer intervals, lasting from hours to days, may improve phenotyping of the diseases, and some recent research has started investigating the regularity and length of AF events across individuals. In addition, because a large proportion of AF individuals present paroxysmal AF this means that long recordings must be performed to accurately diagnose them. This motivates performing long-term continuous electrophysiological recording for the purpose of robust AF diagnosis. On the electrocardiogram (ECG) signal, AF is characterized by an irregular heart rate and by the absence of p-wave. Today, ECG may be recorded using a single portable channel such as the Zio patch (iRhythm, San Francisco). We aim to develop advanced ML approaches to accurately diagnose AF from hours long recordings of a single channel ECG time series and better phenotype patients using unsupervised learning.
The objective was to investigate whether air-coupled ultrasound could be used to distinguish one type of food material from another, and to find foreign bodies and contaminants within food. The aim was then to produce a portable system that could be used on-line for food quality control applications.
Remember, if you feel that you cannot safely extinguish the fire using the portable extinguisher available and if you have not already done so, pull the fire alarm, evacuate the area, and then call the fire department.
A home sleep apnea test is a test that can help diagnose obstructive sleep apnea at home Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference . The device itself is a portable breathing monitor you wear overnight. As you sleep, the device monitors your breathing and oxygen levels to detect and measure pauses in breathing, which are known as apneas. The test calculates an OSA severity score by calculating the average number of lapses in breathing per hour in bed.
To ensure a more accurate reading, avoid napping, caffeine, alcohol, and late or heavy meals Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference on the day of the test. Some experts believe it is better to sleep with the portable test equipment for one to three nights to gather enough data. For many people, sleep apnea is worse when back sleeping Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference as opposed to side sleeping. Collecting data over multiple nights and informing your doctor of your habitual sleep positions might help give a more accurate view of your symptoms.
Citation: Kremers T, Thelen S, Bosbach N, Schnakenberg U (2020) PortaDrop: A portable digital microfluidic platform providing versatile opportunities for Lab-On-A-Chip applications. PLoS ONE 15(9): e0238581.
For operation, commonly used lab bench-based DMF systems need bulky peripheral equipment such as power supply, function generator, multiplexer, voltage amplifier and high-voltage pulse generator. To address point-of-use systems, some attempts have already been made for the development of portable DMF systems. Gong et al. published the first portable DMF device by using a double-sided printed circuit board (PCB) with batteries, droplet and sensing circuits, a microprocessor and an infrared user interface in combination with land grid array sockets to mount the DMF chip [34, 35]. Using a Palm Vx PDA (Personal Digital Assistant), the droplet movement and position were controlled wirelessly via a feedback control.
Yafia et al. published a low-cost portable DMF platform in combination with a smartphone. Here, two small lithium ion batteries serve as the power supply. A boost DC-DC converter amplifies the input voltage of 8 V to 800 V output voltage, which is controlled by either changing the pulse switching frequency or the duty cycle . An Arduino-Micro controls the high-voltage switching circuitry for addressing the pads and is used for the wireless communication with a smartphone via a Bluetooth module . Besides sending serial commands to the microcontroller, the smartphone is also used as a detection and imaging analysis station for calorimetric measurements.
A similar approach of using a smartphone for controlling droplet movements and detecting chemiluminescence was published by Zeng et al. . They developed a low-cost, portable DMF analysis platform in open configuration with three power supplies and an ICL8038 signal generator module, which generates a voltage of 12 Vrms. This square wave is amplified to 45 Vrms by the high-voltage amplifier PA443 from Apex Microtechnology, USA, and then coupled to a relay array. In the original version, only 10 electrode pads are addressed but the develop board can control up to 46 channels at the same time. Only 45 Vrms are needed as the droplet driving voltage because the bottom glass plate is coated with 1 μm thick cyanoethyl pullulan as a high-k dielectric layer . The developed control board is an open-source board named I.O.I.O.-OTG and provides a high-level Java API that manipulates I/O ports by a smartphone.
Recently, Hoang et al. published a portable DMF platform consisting of four main components: a DMF chip, an Arduino-Nano-based control board, a user interface and a heating unit for loop-mediated isothermal amplification (LAMP) reactions . The control board also incorporates a high-voltage DC-DC power converter, which is capable of stepping up to 275 V from a 12 V input. A 64-channel and 300 V-rating serial-to-parallel shift register HV507 (Microchip Technology Inc.) is used as an interface between the 5 V-compatible microcontroller and the high-voltage power line . The HV507 allows for the control of up to 64 electrodes. Because the HV507 is not compatible with AC signals, a complicated solution is presented to address the electrodes individually . A similar approach was published by Wan et al. . Unfortunately, they did not present detailed information about the used hard- and software.
In the portable DMF platform developed by Coudron et al. an 18F45K22 microcontroller contains an 8-bit sine wave lookup table and output to an R-2R resistor ladder to produce a 1 kHz analog sine wave. After amplification, up to 225 Vrms have been applied to 48 driving electrodes individually by a digital potentiometric control and use of high voltage MOSFET switches .
To summarize, portable DMF platforms comprise of five main components: a DMF chip in open or closed configuration, a power supply, a signal generator when AC signals are preferred, a high-voltage generator for droplet actuation and a microcontroller in combination with a switching board to address the electrodes individually. However, the presented approaches all deliver these needs but are lacking the capability to easily extend the setup with analysis devices used for different applications.
The hardware of PortaDrop consists of two different circuit boards: first, a mainboard for the management of all functionalities of the system, which is communicating with the Raspberry Pi 3B+ (Raspberry Pi, purchased at Reichelt Elektronik GmbH & Co. KG, Sande, Germany) via Inter-Integrated Circuit (I2C)-Bus, and second, a board including semiconductor switches operating as pull-down and pull-up networks to activate and deactivate the electrowetting path electrodes on the bottom chip. One board is capable to control up to 59 path electrodes. Multiples of the second board can be connected to the mainboard. The entire hardware of PortaDrop is supplied by only one 5 V USB switching power supply and the power is distributed to all units of the system. A schematic of the system is depicted in Fig 2. The green area represents the main box of PortaDrop, which is completely portable and provides all functionalities needed for EWOD operation as well as integrated electrochemical measurements using the EmStat pico.
The portable all-in-one box DMF PortaDrop system is presented. For its operation, only one common 5 V USB power supply is necessary. The PortaDrop comes with internal functionalities for (i) droplet transport and (ii) an internal EmStat pico potentiostat for various electrochemical sensing application. In the first version, only EIS measurements are implemented. Additional electrochemical protocols provided by the EmStat pico can be easily implemented and make use of the infrastructure on the mainboard, e.g. routing capabilities to set up the electrode configuration (2-, 3- or 4-wire configuration). Compared to portable EWOD systems described before [34, 36, 37, 40, 43, 44, 46, 47] PortaDrop is unique by using a Raspberry Pi and thus a Linux-based operating systems. Beside others, this feature provides the advantage of an easy adaption to a LAN environment as well as to the external devices. The USB ports of the Raspberry Pi offer the beneficial possibility to connect different instruments by plug-n-play. For example, one GPIB-to-USB Adapter can control up to 15 devices at the same time. Of course, keyboard and mouse as well as external monitors can be connected to carry out experiments with PortaDrop more comfortable. 2b1af7f3a8