A review of machine learning techniques in photoplethysmography for the non-invasive cuff-less measurement of blood pressure

Hypertension or high blood pressure is a leading cause of death throughout the world and a critical factor for increasing the risk of serious diseases, including cardiovascular diseases such as stroke and heart failure. Blood pressure is a primary vital sign that must be monitored regularly for the early detection, prevention and treatment of cardiovascular diseases. Traditional blood pressure measurement techniques are either invasive or cuff-based, which are impractical, intermittent, and uncomfortable for patients. Over the past few decades, several indirect approaches using photoplethysmogram (PPG) have been investigated, namely, pulse transit time, pulse wave velocity, pulse arrival time and pulse wave analysis, in an effort to utilise PPG for estimating blood pressure. Recent advancements in signal processing techniques, including machine learning and artificial intelligence, have also opened up exciting new horizons for PPG-based cuff less and continuous monitoring of blood pressure. Such a device will have a significant and transformative impact in monitoring patients’ vital signs, especially those at risk of cardiovascular disease. This paper provides a comprehensive review for non-invasive cuff-less blood pressure estimation using the PPG approach along with their challenges and limitations

Cuffless and Continuous Blood Pressure Estimation from PPG Signals Using Recurrent Neural Networks

This paper proposes cuffless and continuous blood pressure estimation utilising Photoplethysmography (PPG) signals and state of the art recurrent network models, namely, Long Short Term Memory and Gated Recurrent Units. The models were validated on wide range of varying blood pressure and PPG signals acquired from the Multiparameter Intelligent Monitoring in Intensive Care database. Many features were extracted from the PPG waveform and several machine learning techniques were employed in an attempt to eliminate collinearity and reduce the size of input feature vector. Consequently, the most effective features for blood pressure estimation were selected. Experimental results show that the accuracy of the proposed methods outperform traditional models applied in the literature. The results satisfy the American National Standards of the Association for the Advancement of Medical Instrumentation

Fusion d'informations multi-sources pour le suivi des coupes de canne à sucre à La Réunion

Dans ce papier on présente un système d'aide à la décision pour le suivi des coupes de canne à sucre qui intègre des informations provenant de trois sources hétérogènes : une série temporelle d'images satellite, un modèle de culture et des connaissances expertes. Le système est basé sur la logique floue, et ses règles sont générées automatiquement par un arbre de décision flou construit en s'appuyant sur un jeu d'apprentissage. Les performances du système sont analysées sur deux exploitations de canne à la Réunion en utilisant une série d'images SPOT-5. Les résultats montrent que le système peut être utilisé d'une façon opérationnelle : la précision globale en utilisant une série de 3 images par an est supérieure à 92 %; elle atteint 97 % avec 9 images par an. / Multi-source information fusion for sugarcane harvest monitoring in Reunion Island

Pharmacy academics' perspectives toward interprofessional Education prior to its implementation in Qatar: a qualitative study

BACKGROUND: The aim of this study was to explore the perspectives of faculty members and academic administrators, at Qatar University College of Pharmacy, towards interprofessional education (IPE) and collaborative practice by identifying enablers, barriers and resources needed to implement IPE within the pharmacy curriculum. METHODS: A qualitative methodology was employed using focus groups discussions. Two focus groups were conducted, one focus group with faculty members (n?=?5) and another focus group with academic administrators (n?=?5) at Qatar University College of Pharmacy. Focus groups were audio recorded and transcribed verbatim by an independent experienced transcriber and validated by the study principal researcher. Thematic analysis was undertaken to generate key themes and subthemes. RESULTS: The study participants highlighted a number of enablers and challenges encountered as a result of the initial IPE events, for integrating IPE into the pharmacy curriculum. Many provided recommendations and suggestions for effective implementation of IPE. Analysis of the results focused on three main categories: enablers, barriers and recommendations. Overall, seven major themes were identified: 1) intrinsic enabling factors (initial IPE experiences, cross-appointed faculty, accreditation); 2) extrinsic enabling factors (national policy & legislation and advances in pharmacists' role); 3) student related benefits (roles & responsibilities and agents for change); 4) student hindering factors (student engagement, perceptions & attitudes and gender issues); 5) partnering academic institutions (logistical issues, familiarity with other curricula and commitment); 6) practice environment (hierarchy, healthcare professionals' attitude and lack of collaborative practice) and 7) IPE delivery (dedicated structure, IPE curriculum and extrinsic support). CONCLUSION: Pharmacy academics had positive perceptions towards IPE suggesting a high level of support and readiness to pursue IPE and an opportunity for pharmacy academics to drive the IPE agenda forward in Qatar. However, a number of challenges were reported. These are important to consider to ensure the development of effective strategies for the integration and enhancement of IPE and collaborative practice

Magnetohydrodynamic channel flow and variational principles

This paper deals with magnetohydrodynamic channel flow problems. Attention is given to a variational principle where the boundary conditions are incorporated via a suitable functional which is stationary at the solution of the given problem; the trial functions used for the approximate solution need not satisfy any of the given boundary conditions

Methylation Status of Imprinted Genes and Repetitive Elements in Sperm DNA from Infertile Males

Stochastic, environmentally and/or genetically induced disturbances in the genome-wide epigenetic reprogramming processes during male germ-cell development may contribute to male infertility. To test this hypothesis, we have studied the methylation levels of 2 paternally (H19 and GTL2) and 5 maternally methylated (LIT1, MEST, NESPAS, PEG3, and SNRPN) imprinted genes, as well as of ALU and LINE1 repetitive elements in 141 sperm samples, which were used for assisted reproductive technologies (ART), including 106 couples with strictly male-factor or combined male and female infertility and 28 couples with strictly female-factor infertility. Aberrant methylation imprints showed a significant association with abnormal semen parameters, but did not seem to influence ART outcome. Repeat methylation also differed significantly between sperm samples from infertile and presumably fertile males. However, in contrast to imprinted genes, ALU methylation had a significant impact on pregnancy and live-birth rate in couples with male-factor or combined infertility. ALU methylation was significantly high-er in sperm samples leading to pregnancy and live-birth than in those that did not. Sperm samples leading to abortions showed significantly lower ALU methylation levels than those leading to the birth of a baby. Copyright (C) 2011 S. Karger AG, Base

High Injection Effects on Solar Cell Performances

Experiments are performed on solar cells under concentrated sunlight in order to explore fundamental physical processes with high injection conditions. Saturation effects are observed on the cell open circuit voltage and on the extracted values of the recombination current. A large decrease of the initial decay of the transient voltage have been measured. High injection effects are shown to be correlated with the increase of recombination current in the space charge region together with an increase of the emitterbase coupling

Homogenization of dislocation dynamics

In this paper we consider the dynamics of dislocations with the same Burgers vector, contained in the same glide plane, and moving in a material with periodic obstacles. We study two cases: i) the particular case of parallel straight dislocations and ii) the general case of curved dislocations. In each case, we perform rigorously the homogenization of the dynamics and predict the corresponding effective macroscopic elasto-visco-plastic flow rule

Endoscopic Unroofing of a Choledochocele

A 42-year-old man with previous laparoscopic cholecystectomy was referred for further evaluation of recurrent acute pancreatitis. Secretin-enhanced magnetic resonance cholangiopancreatography showed a 16 mm × 11 mm T2 hyperintense cystic lesion at the major papilla (Figure 1). Upper endoscopic ultrasound (EUS) showed a 15 mm × 10 mm oval, intramural, subepithelial lesion at the major papilla (Figure 2). Endoscopic retrograde cholangiopancreatography (ERCP) showed an 18-mm bulging lesion at the major papilla with normal overlying mucosa (Figure 3); injected contrast collected into a 16-mm cystic cavity (Figure 4). Findings were suggestive of type A choledochocele. A 10–12-mm freehand precut papillotomy was made with a monofilament needle-knife (Huibregtse Single-Lumen Needle Knife, Cook Medical, Bloomington, IN) using an ERBE VIO electrocautery system (ERBE USA; Marietta, GA). The incision was made as long as safely possible in an attempt to open the choledochocele completely and thus expose its walls and contents. We used a standard pull sphincterotome and ERBE electrocautery to perform the pancreatic sphincterotomy, followed by placement of a pancreatic stent. Biliary sphincterotomy was performed using the same technique (settings for needle-knife and pull sphincterotomies: Endocut I, blend current, effect 2/duration 2/interval 3). Biopsies of the inverted choledochocele showed biliary mucosa and duodenal columnar epithelium with inflammation and fibrosis, and no dysplasia. Follow-up ERCP at 4 weeks showed adequate unroofing of the choledochocele (Figure 5); the pancreatic stent was subsequently removed. The patient reported no recurrence of acute pancreatitis at 6-, 12-, and 18-month follow-up intervals