Noise-activated barrier crossing in multiattractor dissipative neural networks.

Noise-activated transitions between coexisting attractors are investigated in a chaotic spiking network. At low noise level, attractor hopping consists of discrete bifurcation events that conserve the memory of initial conditions. When the escape probability becomes comparable to the intrabasin hopping probability, the lifetime of attractors is given by a detailed balance where the less coherent attractors act as a sink for the more coherent ones. In this regime, the escape probability follows an activation law allowing us to assign pseudoactivation energies to limit cycle attractors. These pseudoenergies introduce a useful metric for evaluating the resilience of biological rhythms to perturbations.

Array processing of neural signals recorded from the peripheral nervous system for the classification of action potentials.

BACKGROUND: Recording from the peripheral nervous system is key in the development of implantable neural interfaces. Despite a long history of using implantable electrodes for neuro-stimulation, it is difficult to make recordings from the nerves as signal amplitudes are often too small to be detected. Methods exist that are suitable for recording evoked potentials, but these require artificial stimulation of the nerve and thus have limited use in implanted neural interfaces. NEW METHOD: In order to address these issues new methods are developed to analyse spontaneously occurring action potentials by extending an approach called velocity selective recording, which uses longitudinally spaced electrodes to record action potentials as they propagate. The new methods using image processing techniques to automatically identify and classify action potentials without any prior knowledge of their morphology. RESULTS: Simulations are developed to test the methods, and a detailed experimental validation is performed using in-vivo recordings from the L5 dorsal rootlet of rat. Results show that this new approach can discriminate action potentials from both simulated and real recordings and the experimental validation demonstrates an ability to detect dermal stimulation by changes in the firing patterns of different axons. COMPARISON TO EXISTING METHODS: This framework, unlike existing methods, is intrinsically suitable for recordings of spontaneous neural activity. Further it improves upon both the computational complexity and the overall performance of existing methods. CONCLUSION: It is possible to perform on-line discrimination and identification of action potentials without any prior knowledge of their morphology using new image processing inspired methods.

Hybrid Synthetic Receptors on MOSFET Devices for Detection of Prostate Specific Antigen in Human Plasma.

The study reports the use of extended gate field-effect transistors (FET) for the label-free and sensitive detection of prostate cancer (PCa) biomarkers in human plasma. The approach integrates for the first time hybrid synthetic receptors comprising of highly selective aptamer-lined pockets (apta-MIP) with FETs for sensitive detection of prostate specific antigen (PSA) at clinically relevant concentrations. The hybrid synthetic receptors were constructed by immobilizing an aptamer-PSA complex on gold and subjecting it to 13 cycles of dopamine electropolymerization. The polymerization resulted in the creation of highly selective polymeric cavities that retained the ability to recognize PSA post removal of the protein. The hybrid synthetic receptors were subsequently used in an extended gate FET setup for electrochemical detection of PSA. The sensor was reported to have a limit of detection of 0.1 pg/mL with a linear detection range from 0.1 pg/mL to 1 ng/mL PSA. Detection of 1-10 pg/mL PSA was also achieved in diluted human plasma. The present apta-MIP sensor developed in conjunction with FET devices demonstrates the potential for clinical application of synthetic hybrid receptors for the detection of clinically relevant biomarkers in complex samples.

Inexpensive and fast pathogenic bacteria screening using field-effect transistors.

While pathogenic bacteria contribute to a large number of globally important diseases and infections, current clinical diagnosis is based on processes that often involve culturing which can be time-consuming. Therefore, innovative, simple, rapid and low-cost solutions to effectively reduce the burden of bacterial infections are urgently needed. Here we demonstrate a label-free sensor for fast bacterial detection based on metal-oxide-semiconductor field-effect transistors (MOSFETs). The electric charge of bacteria binding to the glycosylated gates of a MOSFET enables quantification in a straightforward manner. We show that the limit of quantitation is 1.9×10(5) CFU/mL with this simple device, which is more than 10,000-times lower than is achieved with electrochemical impedance spectroscopy (EIS) and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-ToF) on the same modified surfaces. Moreover, the measurements are extremely fast and the sensor can be mass produced at trivial cost as a tool for initial screening of pathogens.

Implementing an Evidence-Based Practice Project in the Prevention of Peripheral Intravenous Site Infiltrations in Children.

More than 90% of hospitalized patients require peripheral intravenous (IV) access for the delivery of fluids, nutrition, or medication. Peripheral IV site complications, such as infiltration and phlebitis, account for the greatest risk to most patients receiving infusion therapy. These complications may result in substantial acute or chronic injury, which may be further exacerbated if the affected individual is a child. Evidence suggests that the implementation of bedside-nurse training and more frequent assessment will reduce the risk for peripheral IV site complications. This project evaluates the implementation of these interventions on a pediatric acute care unit.

An adaptive sampling system for sensor nodes in body area networks.

The importance of body sensor networks to monitor patients over a prolonged period of time has increased with an advance in home healthcare applications. Sensor nodes need to operate with very low-power consumption and under the constraint of limited memory capacity. Therefore, it is wasteful to digitize the sensor signal at a constant sample rate, given that the frequency contents of the signals vary with time. Adaptive sampling is established as a practical method to reduce the sample data volume. In this paper a low-power analog system is proposed, which adjusts the converter clock rate to perform a peak-picking algorithm on the second derivative of the input signal. The presented implementation does not require an analog-to-digital converter or a digital processor in the sample selection process. The criteria for selecting a suitable detection threshold are discussed, so that the maximum sampling error can be limited. A circuit level implementation is presented. Measured results exhibit a significant reduction in the average sample frequency and data rate of over 50% and 38%, respectively.

Towards the world-wide ban of indoor cigarette smoking in public places.

In 1984, Dr. C. Everett Koop, then Surgeon General of the US, presented an important speech on the hazards of smoking. In his speech, he stated "The ultimate goal should be a smoke-free society by the year 2000." In addition, the World Health Organization (WHO) has initiated a process to ban smoking globally; on 21 May 2003, at the 56th World Health Assembly, WHO's 192 Member States unanimously adopted the world's first public health treaty, the WHO Framework Convention on Tobacco Control. Although good progress has been made, reaching the ultimate goal is far from certainty. Therefore, it is time to re-visit this crucial public health activity and re-energize the effort to reach this goal. Since numerous reports have been written on the ban of smoking based on benefits to the smokers, the emphasis of our report is on benefits to non-smokers from their exposure to environmental tobacco smoke (ETS). We provide a concise review of the impact of ETS on health and economy. In addition, we examined the different interest groups on supporting and opposing the ban, the role of the government, private citizens and medical professionals on this activity, and certain constraints on implementing the global ban. We also provide some recommendations on how to promote the ban globally. Since cigarette smoking is an unnecessary habit that has devastating consequences around the world, banning of cigarette smoking should be a global mission. A global ban on indoor smoking in public places is an important first step in an international effort to prevent morbidity and mortality caused by tobacco smoking and ETS.