Detection and deletion of motion artifacts in electrogastrogram using feature analysis and neural networks

Electrogastrogram is a surface measurement of gastric myoelectrical activity, and electrogastrography has been an attractive method for physiological and pathophysiological studies of the stomach due to its nonivasive nature. Motion artifacts, however, ruin the electrogastrogram (EGG), and make the analysis very difficult and sometimes even impossible. They must be eliminated from EGG signals before analysis. Up to now, this can only be done by visual inspection, which is not only time-consuming but also subjective. In this study, a method using feature analysis and neural networks has been developed to realize automatic detection and elimination of the motion artifacts in EGG recordings by computer. Experiments were conducted to investigate the characteristics of different motion artifacts. Useful features were extracted, and different combinations of the features used as the input of the neural network were compared to obtain the optimal performance for the detection of motion artifacts using the artificial neural network.     

Silicon neuron simulation with SPICE: tool for neurobiology and neural networks

The paper deals with computer simulations of ‘silicon neurons’, which are assemblies of CMOS circuits that generate the equivalents of the ionic currents and of the action potentials of real (biological) neurons. The circuit simulation program SPICE is used to simulate the generation of action potentials by a silicon neuron. Moreover, the equivalent circuits of silicon synapses are described and the behaviours of simple two- and three-neuron networks are analysed. Implications for the areas of neurobiology and formal neural networks are briefly considered.     

Latent variable discovery in classification models

The naive Bayes model makes the often unrealistic assumption that the feature variables are mutually independent given the class variable. We interpret a violation of this assumption as an indication of the presence of latent variables, and we show how latent variables can be detected. Latent variable discovery is interesting, especially for medical applications, because it can lead to a better understanding of application domains. It can also improve classification accuracy and boost user confidence in classification models.     

Pulmonary function changes in asthmatics associated with low-level SO2 and NO2 air pollution, weather, and medicine intake

This paper presents the response in subjects with asthma to gaseous air-pollution levels, weather, and medicine intake as identified by principal-component analysis and neutral network techniques. Pulmonary function measured by respiratory peak-flow rate in nonallergic asthmatics was associated with ambient, low level, air-pollution concentrations of sulphur dioxide and nitrogen dioxide, temperature, relative humidity, and medicine intake. Results from 27 nonallergic asthmatics aged 18–60 years with well-characterized bronchial asthma and regular medical treatment were analyzed from two cities. During an 8-month period, each subject kept a diary table, which included symptoms, lung function (evening peak flow), medicine intake, and tobbaco smoking.
High intake of medicine and high ambient temperatures correspondend to decreased peak flow. The changes in temperature did not occur in situations with low medicine intake. During frost periods, peak-flow values decreased independently of medicine intake and levels of so². During other times, increased levels of so² and no² increased temperature, and increased intake of medicine, and low relative humidity corresponded to synergistically to decreased peak flow at levels above 40μ/m³.     

Involving the patient: a prospective study on use, appreciation and effectiveness of an information system in head and neck cancer care

OBJECTIVE: To determine use, appreciation and effectiveness of an electronic health information support system in head and neck (H&N) cancer care. DESIGN: A prospective evaluation study. The evaluated system has four different functions: (1) communication amongst health care providers and between health care providers and patients, (2) information for health care providers and patients, (3) contact with fellow sufferers and (4) monitoring of discharged patients by means of electronic questionnaires. Evaluation of the system was done both objectively using automatically created log files and stored messages, and subjectively by using paper questionnaires from patients and general practitioners (GPs). SETTING: Department of Otorhinolaryngology and Head and Neck Surgery of a tertiary health care centre in the Netherlands. The system was put at patients' disposal for a period of 6 weeks following discharge from the hospital after surgery for H&N cancer, and was additional to standard care. PARTICIPANTS: Head and neck cancer patients, hospital physicians, members of a hospital-based support team, GPs, district nurses and speech therapists. MAIN OUTCOME MEASURES: Actual use of the system by patients and health care providers. Patients' appreciation for each of the system's four different functions. GPs' appreciation for the system. Capability to detect potential patient problems with the system. RESULTS: The system was used by 36 H&N cancer patients, 10 hospital physicians, 2 members of the support team, 8 GPs, 2 district nurses and 2 speech therapists. The total number of patient-sessions was 982: an average of 27.3 sessions per patient during the 6 weeks study period. In total, 456 monitoring questionnaires were completed. The support team in hospital responded with 231 actions. In 16 cases, an extra appointment was made for a patient with the hospital physician. Out of these cases, immediate action was considered necessary eight times. Patients appreciated the system highly, rating it with an average score of 8.0 on a 10-point scale. All patients used the monitoring function, and rated 'monitoring' with a mean score of 8.0 on a 10-point scale. Least used and appreciated was the 'contact with fellow sufferers' function. Only 8 out of possible 36 GPs used the system, rating it with an average of 5.6 on a 10-point scale. CONCLUSIONS: The electronic health information support system was used intensively and highly appreciated by H&N cancer patients. The system enabled the early detection of occurring health problems that required direct intervention. ICT can play an additional role in the management of patients, also in a relatively elderly and computer illiterate patient population.     

Reversible Photo‐Mechanical Switching Behavior of Azobenzene‐Containing Semi‐Interpenetrating Network under UV and Visible Light Irradiation

Summary: Light‐induced reversible changes in elasticity of semi‐interpenetrating network (semi‐IPN) films bearing azobenzene moieties were achieved under both ultraviolet (UV) and visible light irradiation. The semi‐IPN film was prepared by a cationic copolymerization of azobenzene‐containing vinyl ethers in a linear polycarbonate (PC) film as a matrix. When the irradiation was switched on and off, the semi‐IPN film showed rapid reversible deformation with the same behavior occurring over a range of wavelengths, including both the UV and visible regions. The observed reversible deformation of the film was attributed to the decrease in the film's elasticity, which was assumed to be caused by the frequent trans‐cis cycling isomerization of azobenzene moieties taking place during the UV and visible light irradiation. This cycling makes it difficult for the azobenzene groups to aggregate, thus hindering their ability to function as pseudo‐crosslinking points.

     

Associations of social capital with binge drinking in a national sample of adults: The importance of neighborhoods and networks

BackgroundWhile considerable research on adult binge drinking has focused on social influences, the potential role of social capital has been largely overlooked. This study examines the role of social capital, assessed in terms of both neighborhood and social network characteristics, in understanding adult binge drinking.MethodsAdults ages 30–80 were randomly drawn from the RAND American Life Panel and completed an online survey (analytic sample n = 1383). The main predictor variables were neighborhood cohesion, neighborhood order, and social network density. Associations of social capital with past month binge drinking (any, number of days) were examined, controlling for demographic characteristics.ResultsZero-inflated negative binominal regression analysis indicated that any binge drinking was more likely among adults who lived in highly ordered neighborhoods and who had denser social networks but was negatively associated with neighborhood cohesion. However, binge drinking was more frequent among those who lived in neighborhoods lacking order and who had sparser social networks, but had no association with neighborhood cohesion. Age was not found to moderate associations of social capital with binge drinking.ConclusionsGiven that the associations of social capital with adult binge drinking behavior appear to differ by level of influence and type of drinking behavior, there is a need to gain a more nuanced understanding of these complex associations, including the mechanisms through which they operate.     

The Relationship Between Violence Syndemics and Sexual Risk Behaviors Among African American Adolescents: Implications for Future Research

PurposeWe present a conceptual framework based on a review of the literature to highlight the interconnecting and reinforcing elements of a violence syndemic and how this syndemic influences sexual risk behaviors among African American heterosexual adolescents.MethodsWe review existing peer-reviewed published research from 2000 to 2020 that links a violence syndemic (i.e., racism and race-related stress, neighborhood and police violence, peer violence, and family violence and disruptions) to adolescent sexual risk behaviors. Empirical findings and theoretical underpinnings are used to document this relationship and illuminate the factors that mediate this relationship.ResultsEmpirical studies support the links between specific types of violence and sexual risk behaviors among African American adolescents. Further, existing studies point to the important relationships among the specific types of violence, supporting a violence syndemic approach.ConclusionsWhile more researchers are examining socio-ecological contextual factors as important predictors for sexual risk behaviors, there remains inadequate understanding about how violence types reinforce one another to heighten sexual risk behaviors among African American heterosexual adolescents. This article presents new directions for adolescent research, especially how a violence syndemic approach can be used to explain sexual risk, but also to refocus intervention design on the complex burdens experienced by this population.     

Enforcing Imprecise Constraints on Generative Adversarial Networks for Emulating Physical Systems

Generative adversarial networks (GANs) were initially proposed to generate images by learning from a large number of samples. Recently, GANs have been used to emulate complex physical systems such as turbulent flows. However, a critical question must be answered before GANs can be considered trusted emulators for physical systems: do GANs-generated samples conform to the various physical constraints? These include both deterministic constraints (e.g., conservation laws) and statistical constraints (e.g., energy spectrum of turbulent flows). The latter have been studied in a companion paper (Wu et al., Enforcing statistical constraints in generative adversarial networks for modeling chaotic dynamical systems. Journal of Computational Physics. 406, 109209, 2020). In the present work, we enforce deterministic yet imprecise constraints on GANs by incorporating them into the loss function of the generator. We evaluate the performance of physics-constrained GANs on two representative tasks with geometrical constraints (generating points on circles) and differential constraints (generating divergence-free flow velocity fields), respectively. In both cases, the constrained GANs produced samples that conform to the underlying constraints rather accurately, even though the constraints are only enforced up to a specified interval. More importantly, the imposed constraints significantly accelerate the convergence and improve the robustness in the training, indicating that they serve as a physics-based regularization. These improvements are noteworthy, as the convergence and robustness are two well-known obstacles in the training of GANs.     

High resolution evoked potentials of cognition

Summary The precision of four methods of quantifying neuroelectric signals has been improved by increasing EEG spatial sampling, using up to 124 electrodes, and by accurate anatomical registration of the EEG with Magnetic Resonance Images (MRIs). One such method, equivalent dipole modeling, is a well-known form of source localization which is useful when the generator of the scalp recorded signal approximates a simple dipolar source, as is usually the case with early and mid-latency Evoked Potentials (EPs). Two methods of enhancing spatial detail which benefit from increased spatial sampling include the Laplacian Derivation and the Finite Element Deblurring method. The latter is a new technique which estimates the EP distribution at the superficial cortical surface. The fourth method, Evoked Potential Covariance, characterizes the spatiotemporal relationships among EP segments at different recording sites. This is useful when studying functional neural networks underlying higher cognitive functions. These methods are reviewed and examples of results of their application in recent experiments are presented.Supported by competitive grants from The National Institute of Mental Health, The National Institute of Neurological Diseases and Stroke, The Air Force Office of Scientific Research, The Office of Naval Research, The National Science Foundation NASA and The National Institute on Alcohol Abuse and Alcoholism of the United States Federal Government. Thanks to all members of the EEG Systems Laboratory and SAM Technology, past and present, for their vital contributions to the work presented here.This paper is based on an invited lecture given at the Tenth Anniversary Meeting of The Japanese Society for Brain Electromagnetic Topography held in Fukuoka, Japan in September, 1992.