Design of a radio-linked implantable cochlear prosthesis using surface acoustic wave devices

Cochlear prosthesis systems for postlingually deaf individuals (those who have become deaf due to disease or injury after having developed mature speech capability) are considered. These systems require the surgical implantation of an array of electrodes within the cochlea and are driven by processed sound signals from outside the body. A system that uses an analog signal approach for transcutaneous transfer of six processed speech data channels using frequency multiplexing is described. The system utilizes a filterbank of six narrowband surface acoustic wave (SAW) filters in the range 72-78 MHz with a 1.2-MHz channel spacing to multiplex the six carrier signals, frequency modulated, by the processed speech signals, onto a composite signal. The same SAW filters are used in the receiver filterbank for signal separation, but are housed in a miniaturized package. The system includes a portable transmitter and a receiver package which is to be implanted in the patient. The implanted circuits are supplied exclusively from power transferred from outside the body via a separate 10-MHz transcutaneous link.     

A Flexible Automated Waveform Recorder Data-Acquisition Program

Software has been developed to record signals in automated data-acquisition systems that support pulsed power accelerators at Sandia. The software achieves flexibility by being entirely table driven. Before each accelerator shot the program processes input files and then sets up and checks out all programmable hardware. After the shot, the program automatically reads each signal, corrects it, and stores it in a disc file. The software is currently running in three different facilities with up to 60 waveform recorder channels.     

An Electrically-Driven GaAs Nanowire Surface Plasmon Source

Over the past decade, the properties of plasmonic waveguides have extensively been studied as key elements in important applications that include biosensors, optical communication systems, quantum plasmonics, plasmonic logic, and quantum-cascade lasers. Whereas their guiding properties are by now fairly well-understood, practical implementation in chipscale systems is hampered by the lack of convenient electrical excitation schemes. Recently, a variety of surface plasmon lasers have been realized, but they have not yet been waveguide-coupled. Planar incoherent plasmonic sources have recently been coupled to plasmonic guides but routing of plasmonic signals requires coupling to linear waveguides. Here, we present an experimental demonstration of electrically driven GaAs nanowire light sources integrated with plasmonic nanostrip waveguides with a physical cross-section of 0.08λ(2). The excitation and waveguiding of surface plasmon-polaritons (SPPs) is experimentally demonstrated and analyzed with the help of full-field electromagnetic simulations. Splitting and routing of the electrically generated SPP signals around 90° bends are also shown. The realization of integrated plasmon sources greatly increases the applicability range of plasmonic waveguides and routing elements.     

Programmable Hydrogel Ionic Circuits for Biologically Matched Electronic Interfaces

The increased need for wearable and implantable medical devices has driven the demand for electronics that interface with living systems. Current bioelectronic systems have not fully resolved mismatches between engineered circuits and biological systems, including the resulting pain and damage to biological tissues. Here, salt/poly(ethylene glycol) (PEG) aqueous two‐phase systems are utilized to generate programmable hydrogel ionic circuits. High‐conductivity salt‐solution patterns are stably encapsulated within PEG hydrogel matrices using salt/PEG phase separation, which route ionic current with high resolution and enable localized delivery of electrical stimulation. This strategy allows designer electronics that match biological systems, including transparency, stretchability, complete aqueous‐based connective interface, distribution of ionic electrical signals between engineered and biological systems, and avoidance of tissue damage from electrical stimulation. The potential of such systems is demonstrated by generating light‐emitting diode (LED)‐based displays, skin‐mounted electronics, and stimulators that deliver localized current to in vitro neuron cultures and muscles in vivo with reduced adverse effects. Such electronic platforms may form the basis of future biointegrated electronic systems.     

Effects of pulse rate,fundamental frequency and burst density on auditory similarity

Auditory displays are currently used in many medical, automotive and aviation settings. Although there are many existing guidelines for developing effective auditory signals, there is a need for more research considering the interaction between signals within a display, especially when sounds originate from conceptually distinct referent systems. Identifying the parameters that are most relevant to auditory similarity can facilitate acoustic branding and the development of guidelines that ensure signals for different systems are distinct without requiring standardisation. Twenty-seven undergraduate students judged the similarity of a set of abstract sounds varying in tempo, or pulse rate, fundamental frequency and burst density. Results indicate that no single parameter is entirely responsible for determining auditory similarity, but temporal characteristics are most salient. These findings have implications for acoustic branding and suggest that designers intending to ensure perceptual similarity and separation between differentially mapped sounds should manipulate temporal characteristics before frequency or burst density.     

全设计频段束宽恒定的低旁瓣时域波束形成

为了在空域无失真地接收宽带信号和有效地抑制环境干扰,提出了全设计频段束宽恒定的低旁瓣时域波束形成方法。首先,把宽带信号分为几个子带,应用半定规划的优化方法设计这些子带中心频率上的加权,使所形成的波束主瓣与设计带宽中最低频率上的波束相同,同时约束其具有低旁瓣特征。然后,设计FIR滤波器拟合这些离散频率点上恒定束宽加权所表示的幅相加权。显然,设计得到的FIR滤波器的幅相响应给出了全设计频段上的幅相加权。最后应用该方法,针对阵元具有方向性的12元均匀离散圆弧阵,设计覆盖一个倍频程的低旁瓣时域恒定束宽波束形成器,并使用线性调频信号作为测试信号,验证了所提方法的有效性。     

Orbiting Self-Organization of Filament-Tethered Surface-Active Droplets

Dissipative chemical systems hold the potential to enable life-like behavior in synthetic matter, such as self-organization, motility, and dynamic switching between different states. Here, out-of-equilibrium self-organization is demonstrated by interconnected source and drain droplets at an air-water interface, which display dynamic behavior due to a hydrolysis reaction that generates a concentration gradient around the drain droplets. This concentration gradient interferes with the adhesion of self-assembled amphiphile filaments that grow from a source droplet. The chemical gradient sustains a unique orbiting of the drain droplet, which is proposed to be driven by the selective adhesion of the filaments to the front of the moving droplet, while filaments approaching from behind are destabilized upon contact with the hydrolysis product in the trail of the droplet. Potential applications are foreseen in the transfer of chemical signals amongst communicating droplets in rearranging networks, and the implementation of chemical reactions to drive complex positioning routines in life-like systems.     

Quantum Amplifier Performance of Strongly Driven Atomic Systems

Abstract

In this paper we consider the gain obtained in strongly driven and damped atomic systems within the framework of quantum amplifier theory. The atomic system suffices to break the time-reversal symmetry and no rigged reservoirs or continuous spectra are needed. We consider both the driven two-level system and Λ-type systems. We derive master equations for the boson mode using adiabatic elimination techniques and use these equations to determine the amplifier performance of the systems. We find that in both cases the quantum limit on the noise can be approached without introducing any quantum features of the strong driving field. The basic interaction event between the amplified bosons and the atomic system suffices to saturate the noise limit. Ideal amplifier performance is, however, found only in the limit when the driving field is far off resonance, and then the ensuing gain becomes very small. The result is understandable because in this limit little population is accumulated on the upper level which drives the noise through spontaneous emission. We believe our method and main conclusions to be quite universal, and they provide insight into the operation of quantum amplifiers.     

Amplitude response of Fabry-Perot frequency discriminators

The amplitude noise responses of optical-frequency-discriminating systems, based on Fabry-Perot cavities with intensity noise compensation, are analyzed considering also the effect of the resonator transient. From the point of view of amplitude noise immunity, systems based on transmission or reflection alone behave in a quite similar way within the discriminator bandwidth, whereas a proper combination of both these signals not only increases the sensitivity to frequency noise but also allows for higher rejection to amplitude noise.     

Systematic and Adaptive Characterization Approach for Behavior Modeling and Correction of Dynamic Nonlinear Transmitters

This paper proposes a comprehensive and systematic characterization methodology that is suitable for the forward and reverse behavior modeling of wireless transmitters (Txs) driven by wideband-modulated signals. This characterization approach can be implemented in adaptive radio systems since it does not require particular signal or training sequences. The importance of the nature of the driving signal and its average power on the behavior of radio-frequency Txs are experimentally investigated. Critical issues related to the proposed characterization approach are analytically studied. This includes a new delay-estimation method that achieves good accuracy with low computational complexity. In addition, the receiver linear calibration and its noise budget are investigated. To demonstrate the accuracy and robustness of the proposed method, a full characterization (including the memoryless nonlinearity and the memory effects) of a 100-W Tx driven by a multicarrier wideband code-division multiple-access signal is carried out, and its forward and reverse models are identified. Cascading the identified reverse model derived using the proposed methodology and the Tx prototype leads to excellent compensation of the static nonlinearities and the memory effects exhibited by the latter. Critical issues in implementing this approach are also discussed.     

Boolean AND and OR logic for cell signalling gateways: a communication perspective

Cell signalling plays a vital role in development, sustaining, differentiation, and reproduction of cells. Pathways involved in signalling networks are quite interwoven and complex. Complexity encountered in understanding these pathways is often reduced with the help of Boolean circuit representation. In this study, the authors provide communication aspect of the signalling pathways that have two input Boolean logic AND/OR implemented at the rear effector protein. Communication is assumed to be taking place in extracellular and intracellular environment. The two environments are connected using a receptor protein acting as relay between a molecular source and effector protein. Each relay detects molecules from outside environment and stimulates the production of signals in the intracellular space. These signals/molecules further activate the effector protein which acts as a Boolean switch driven by AND/OR logic. Assuming Poisson reception at the relay as well as at the receiver, the authors provide probability of error of the AND and OR Boolean logic communication systems. Furthermore, reliability and some capacity bounds are deduced for the given Boolean communication system.Inspec keywords: cellular biophysics, integrated circuit modelling, stochastic processes, probability, cellular transport, proteins, molecular biophysics, Boolean functions, biochemistryOther keywords: cell signalling, communication perspective, signalling networks, Boolean circuit representation, communication aspect, signalling pathways, input Boolean logic, rear effector protein, extracellular environment, intracellular environment, receptor protein, relay, stimulates, signals/molecules, Boolean switch, Boolean logic communication systems, given Boolean communication system     

Information theory in optoelectronic systems: introduction to the feature.

There has been an explosion of recent interest concerning information theory in optoelectronic (OE) systems. This interest has been motivated in part by (1) the accelerating deployment of OE components into digital systems, (2) the blurring of the analog-digital interface within many OE applications, and (3) the increasing sophistication and complexity of computational tools. These trends are being driven by revolutionary improvements in both OE devices and electronic processors together with increasing demand for high-speed and high-capacity solutions. This feature addresses the application of information- and communication-theoretic concepts, algorithms, and techniques to important problems in OE system analysis and design.     

First-passage probabilities for randomly excited systems: Diffusion methods

For systems driven by wide-band random excitation processes it is possible to model the response as a multi-dimensional continuous Markov, or diffusion, process. This approach enables, in principle, the determination of the ‘first-passage’ probability that the system response vector exceeds a prescribed safe domain, at least once, within a specified interval of time. This paper reviews the current state of knowledge regarding the determination of first-passage probabilities, and related statistics, by diffusion methods. Attention is focussed on systems which are of interest in mechanical and structural engineering, but the theoretical techniques presented have applications in many other areas.     

Multiplicative cases from additive cases: Extension of Kolmogorov–Feller equation to parametric Poisson white noise processes

In this paper the response of nonlinear systems driven by parametric Poissonian white noise is examined.As is well known, the response sample function or the response statistics of a system driven by external white noise processes is completely defined. Starting from the system driven by external white noise processes, when an invertible nonlinear transformation is applied, the transformed system in the new state variable is driven by a parametric type excitation. So this latter artificial system may be used as a tool to find out the proper solution to solve systems driven by parametric white noises. In fact, solving this new system, being the nonlinear transformation invertible, we must pass from the solution of the artificial system (driven by parametric noise) to that of the original one (driven by external noise, that is known). Moreover, introducing this invertible nonlinear transformation into the Itô’s rule for the original system driven by external input, one can derive the Itô’s rule for systems driven by a parametric type excitation, directly. In this latter case one can see how natural is the presence of the Wong–Zakai correction term or the presence of the hierarchy of correction terms in the case of normal and Poissonian white noise, respectively. Direct transformation on the Fokker–Planck and on the Kolmogorov–Feller equation for the case of parametric input are found.     

Multiplexed optical operation of distributed nanoelectromechanical systems arrays

We report a versatile all optical technique to excite and read-out a distributed nanoelectromechanical systems (NEMS) array. The NEMS array is driven by a distributed, intensity modulated optical pump through the photothermal effect. The ensuing vibrational response of the array is multiplexed onto a single probe beam in the form of a high frequency phase modulation. The phase modulation is optically down converted to a low frequency intensity modulation using an adaptive full-field interferometer, and subsequently detected using a CCD array. Rapid and single step mechanical characterization of ～44 nominally identical high-frequency resonators is demonstrated. The technique may enable sensitivity improvements over single NEMS resonators by averaging signals coming from a multitude of devices in the array. In addition, the diffraction limited spatial resolution may allow for position-dependent read-out of NEMS sensor chips for sensing multiple analytes or spatially inhomogeneous forces.     

Same phase drive-type ultrasonic motors using two degenerate bending vibration modes of a disk

Same-phase drive-type ultrasonic motors, using two degenerate bending vibration modes of a disk, are presented. The distinctive feature of the motor is in using the standing wave modes. The motor is not driven by two input signals with different phases, but by input signals with the same phase. Therefore, only one amplifier is sufficient to drive the motor. The experimental results have proved that the motor can yield stable operational characteristics at low speed and high torque.     

Cancer‐Associated,Stimuli‐Driven,Turn on Theranostics for Multimodality Imaging and Therapy

Advances in bioinformatics, genomics, proteomics, and metabolomics have facilitated the development of novel anticancer agents that have decreased side effects and increased safety. Theranostics, systems that have combined therapeutic effects and diagnostic capabilities, have garnered increasing attention recently because of their potential use in personalized medicine, including cancer‐targeting treatments for patients. One interesting approach to achieving this potential involves the development of cancer‐associated, stimuli‐driven, turn on theranostics. Multicomponent constructs of this type would have the capability of selectively delivering therapeutic reagents into cancer cells or tumor tissues while simultaneously generating unique signals that can be readily monitored under both in vitro and in vivo conditions. Specifically, their combined anticancer activities and selective visual signal respond to cancer‐associated stimuli, would make these theranostic agents more highly efficient and specific for cancer treatment and diagnosis. This article focuses on the progress of stimuli‐responsive turn on theranostics that activate diagnostic signals and release therapeutic reagents in response to the cancer‐associated stimuli. The present article not only provides the fundamental backgrounds of diagnostic and therapeutic tools that have been widely utilized for developing theranostic agents, but also discusses the current approaches for developing stimuli‐responsive turn on theranostics.     

Clustertools — ein neues Anlagenkonzept für die Schichtherstellung in der Mikroelektronik

A new generation in wafer processing equipment for deposition and etching in the microelectronic chipproduction is established. The systems are capable of multiple, independent processing steps within one vacuum environment for cleaning, deposition, etching and annealing. The implementation is mainly driven by the technological need to control interfaces in the nm range and the reduction of particles. There are also advantages for the control of a production process with increasing complexity and number of process steps with a wider variety of products. High requirements are made on the system reliability.