In this paper, we present the design, development, and validation of a 'modular photoplethysmography (PPG) system called ZenPPG. This portable, dual-channel system has the capability to produce "raw" PPG signals at two different wavelengths using commercial and/or custom-made PPG sensors. The system consists of five modules, each consisting of circuitry required to perform specific tasks, and are all interconnected by a system bus. The ZenPPG system also facilitates the acquisition of other physiological signals on-demand including electrocardiogram (ECG), respiration, and temperature signals. This report describes the technical details and the evaluation of the ZenPPG along with results from a pilot in vivo study on healthy volunteers. The results from the technical evaluations demonstrate the superiority and flexibility of the system. Also, the systems' compatibility with commercial pulse oximetry sensors such as the Masimo reusable sensors was demonstrated, where good quality raw PPG signals were recorded with the signal-to-noise ratio (SNR) of 50.65 dB. The estimated arterial oxygen saturation (SpO 2) values from the system were also in close agreement with commercial pulse oximeters, although the accuracy of the reported SpO 2 value is dependent on the calibration function used. Future work is targeted toward the development of variations of each module, including the laser driver and fiber optic module, onboard data acquisition and signal processing modules. The availability of this system will help researchers from a wide range of disciplines to customize and integrate the ZenPPG system to their research needs and will most definitely enhance research in related fields.

Abstract-Photoplethysmography (PPG) is a technique that uses light to non-invasively obtain a volumetric measurement of an organ with each cardiac cycle. Pulse Oximetry (PO) is an empirical technique which allows the arterial blood oxygen saturation (SpO 2 ) evaluation from the PPG signals. There have been many reports in the literature suggesting that other arterial blood chemical components can be evaluated from the PPG signals. Most attempts to perform such evaluation on empirical bases have failed, especially for components concentrations. This paper introduces a non-empirical rational theory called Dynamic Pulsatile Spectroscopy (DPS) which can be used to analytically investigate the phenomena of PPG. The DPS theory provides the mathematically rigid method of how PPG signals can be used for arterial blood analysis to evaluate its chemical component concentrations and molar fractions spectroscopically and transcutaneously. It also highlights what other signals might be required for such evaluation. DPS opens the possibility of extending PPG application for blood analysis beyond conventional PO. The DPS basic principles are introduced in this paper.

Photoplethysmography (PPG) is a technique that uses light to noninvasively obtain a volumetric measurement of an organ with each cardiac cycle. A PPG-based system emits monochromatic light through the skin and measures the fraction of the light power which is transmitted through a vascular tissue and detected by a photodetector. Part of thereby transmitted light power is modulated by the vascular tissue volume changes due to the blood circulation induced by the heart beating. This modulated light power plotted against time is called the PPG signal. Pulse Oximetry is an empirical technique which allows the arterial blood oxygen saturation (SpO 2-molar fraction) evaluation from the PPG signals. There have been many reports in the literature suggesting that other arterial blood chemical components molar fractions and concentrations can be evaluated from the PPG signals. Most attempts to perform such evaluation on empirical bases have failed, especially for components concentrations. This paper introduces a non-empirical physical model which can be used to analytically investigate the phenomena of PPG signal. Such investigation would result in simplified engineering models, which can be used to design validating experiments and new types of spectroscopic devices with the potential to assess venous and arterial blood chemical composition in both molar fractions and concentrations non-invasively.

Abstract-In the UK, in emergency situations, health professionals rely on patients to provide information about their medical history. However, in some cases patients may not remember their medication, long term illnesses or allergies, or be able to communicate this information. As a national on-line integrated patient record system has not yet been established, this paper introduces an on-going project 'MyCare Card' abbreviated as MyC 2 which aims to design and implement a patient held electronic health record device and corresponding user interface software.

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-In most emergency situations, health professionals rely on patients to provide information about their medical history. However, in some cases patients might not be able to communicate this information, and in most countries an online integrated patient record system has not been adopted yet. Therefore, in order to address this issue the ongoing project MyCare Card (MyC 2 , www.myc2.org) has been established. The aim of this project is to design, implement, and evaluate a prototype patient held electronic health record device. Due to the wide range of user requirements, the device, its communication interface, and its software have to be compatible with many common platforms and operating systems. Thus, this paper is addressing one of the software compatibility matters-the cross-platform GUI implementation. It introduces a portable object-oriented GUI framework, suitable for a declarative layout definition, components customization, and fine model-view code separation. It also rationalizes the hardware and software solutions selected for this project implementation. Permanent repository linkIndex Terms-Graphical user interface (GUI), health care, patient care, personal health record, Python.