Signal Emitter Research Articles

Sensory Elements and Devices Operational Diagnostic Blood Glucose Using Near Infrared Radiation

The article describes a method for measuring the concentration of glucose in human blood by the non-invasive methods using near-infrared optical technology. In medical practice, glucose concentration in the blood in most cases is measured by invasive methods involving the collection of blood from the finger or vein, while non-invasive devices for determining the level of glucose preserve the operational measurement of blood-borne levels. Invasive methods are expensive and painful. Frequent piercing of fingers causes corns on the skin, and also increases the risk of spreading infectious diseases. Thus, the development of a system of non-invasive measurement of glucose in the blood will be useful for patients with diabetes mellitus. The proposed system consists of emitters of signals with a wavelength of 940 nm. These optical signals are sent through the earlobe, and the rays passing through it are fixed by a phototransistor located on another part of the device. The concentration of glucose in the blood is determined by analyzing the intensity variation obtained after passing the signal. The accuracy of the measurements of the proposed system can be improved by integrating its sensitive and emitting elements based on the SOI of the CMOS structures.

In-vitro validation of a closed-loop optogenetic stimulation device.

Closed-loop optogenetic stimulation (CLOS) involves real-time neural data collection and analysis, feedback control, and optical neuromodulation. Despite emergence of the CLOS devices, methods for validating such devices in-vitro are limited. This paper presents a CLOS device and introduces an in-vitro setup for validating CLOS devices. The CLOS device consists of an electrode, a neural detector, a control algorithm, and an optogenetic stimulator. The in-vitro setup consists of saline solution, a neural signal emitter, a photodiode and its amplifier, and a closed-loop simulation program. Synthetic neural signals are delivered to the CLOS device, and based on the sensed optical stimulations from the light source, the properties of the delivered neural signals are changed. Experiments are conducted to evaluate the closed-loop operation of the CLOS device, and verify the capability of the in-vitro setup to for validating the CLOS devices. The in-vitro setup enables refinement of CLOS devices before arduous in-vivo trials.

A new beam parameter product for the collimating and focusing lenses’ impact on semiconductor laser

The M2 factor and other parameters often used in evaluating the beam quality of lasers are not sufficient. Based on the beam characteristics of semiconductor laser, the paper presents a new expression for the beam quality on semiconductor laser. The new beam quality factor can not only evaluate the beam quality of the semiconductor laser but also evaluate the beam quality of the semiconductor laser chips via collimating and focusing lenses. The results give us grounds to make the following conclusions: the new beam parameter product succeeds in its universality and adaptability in collimating and focusing lenses of a multi-emitter semiconductor laser made by stacking several signal emitter chips.

Efficient signal emitters and detectors

Efficient signal emitters and detectors

Mitohormesis in exercise training

Hormesis is a process whereby exposure to a low dose of a potentially harmful stressor promotes adaptive changes to the cell that enables it to better tolerate subsequent stress. In recent years this concept has been applied specifically to the mitochondria (mitohormesis), suggesting that in response to a perturbation the mitochondria can initiate and transduce a signal to the nucleus that coordinates a transcriptional response resulting in both mitochondrial and non-mitochondrial adaptations that return and maintain cellular homeostasis. In this review we summarize the evidence that mitohormesis is a significant adaptive-response signaling pathway, and suggest that it plays a role in mediating exercise-induced adaptations. We discuss potential mitochondrial emitters of retrograde signals that may activate known exercise-sensitive transcription factors to modulate transcription responses to exercise, and draw on evidence from mitochondrial dysfunction animal models to support a role for mitohormesis in mitochondrial biogenesis. Studies directly linking mitohormesis to the exercise training response are lacking, however mounting evidence suggests numerous signals are emitted from the mitochondria during exercise and have the potential to induce a nuclear transcription response, with reactive oxygen species (ROS) being the primary candidate.

Stress evaluation of laser cladding coating with critically refracted longitudinal wave based on cross correlation function

Research on stress evaluation of laser cladding coating with critically refracted longitudinal wave was introduced in this paper. Two critically refracted longitudinal wave transducers with 5MHz frequency, spacing between which was constant, were employed as signal emitter and receiver. Based on acoustoelastic equation deduction, relationship between the difference in time of flight and tensile stress is obtained. Combing with cross correlation theory, the difference in time of flight between stressed and unstressed critically refracted longitudinal signals was calculated. Results show that stress evaluation is affected by layer interface and anisotropic microstructure of laser cladding coating, precision of stress evaluation of laser cladding coating increases as step length increases until it attains one cycle. In addition, influence of waveform distortion caused by microstructure of laser cladding coating on stress evaluation is discussed. At last, verification test is carried out and the experimental result is well consistent with theoretical result.

Evolving détente: the origin of warning signals via concurrent reciprocal selection

Casualties and impediments inflicted on consumers by defended prey, and vice versa, may be averted by vocalizations, postures, coloration, scents, and other warning, or so-called aposematic, displays. The existence of aposematic signals has challenged biologists who have sought plausible mechanisms for their evolution. Here, we elaborate on the rationale for the hypothesis that aposematic signals arise via concurrent reciprocal selection (CRS) enacted between inimical signal receivers and signal emitters, where signal emitters, e.g., defended prey, select against non-discriminating signal receivers, e.g., predators, and signal receivers select against unrecognized signal emitters. It is postulated that this mutual selective interaction culminates in the survival of discriminating signal receivers that avoid signal emitters, and recognized (distinctive) signal emitters that are avoided by signal receivers. A CRS hypothesis for the evolution of aposematism, therefore, maintains that distinctive features of prey arise in response to selection imposed by consumers, and that avoidances of those features by consumers arise in response to selection imposed by defended prey. We discuss the plausible inception of aposematism via CRS in light of related hypotheses, and describe points of concordance with previous observations and suggestions on the origin of aposematism. Aposematism arising via CRS is not contingent upon the relatedness of signallers, aversions acquired by learning, or other conditions postulated for some other evolutionary hypotheses. CRS is a credible alternative hypothesis for the evolution of warning signals in diverse consumer-prey interactions.

Anisotropic structure affects thickness measurement of laser cladding coating with surface ultrasonic wave based on cross-correlation function

Thickness evaluation of laser cladding coating with surface ultrasonic wave method was introduced in this research. Two surface ultrasonic wave transducers with 5 MHz frequency, distance between which was constant, were employed as signal emitter and receiver. Based on cross-correlation theory, the difference in time of flight between surface ultrasonic signals corresponding to different coating thickness was calculated. The relationship between the difference in time of flight and coating thickness is obtained. The results show that coating thickness evaluation is affected by microstructure of laser cladding coating, and accuracy of coating thickness evaluation increases as step length increases until it attains one cycle. In addition, influence of waveform distortion caused by microstructure of laser cladding coating on coating thickness evaluation is discussed. At last, verification test is carried out and the error is in the allowance range.

Enlarged Deployment Regions to Circumvent the Conditional Dependence and Composite Hypothesis Problems in Sensor Detection Systems

It is usually difficult to design randomly deployed sensor systems to detect a signal emitter in a region of interest because measurements are conditionally dependent in general and the alternative hypothesis is composite. To circumvent these problems, this paper presents two system design approaches: in Approach 1, a modified decay function is considered; in Approach 2, a modified region of interest and a suitable distribution for the emitter location are considered; and both approaches use enlarged sensor deployment regions. It is shown that both approaches cause the measurements to become conditionally independent and identically distributed, cause the alternative hypothesis to become simple, and generate designs that ensure a detection performance. This paper further evaluates how conservative each approach is and compares them, helping a designer choose the most suitable approach for a situation.

Probability of mixing up the nearest neighbor robot under target enclosure by robot swarm

This paper analyzes conditions in which a robotic swarm with a simplest communication device can succeed to enclose a target. The robots have to know directions to their each nearest neighbors. Each robot has a same signal emitter like a torch and they can observe the sum of the intensity of their torches. We analyze the probability to the mistake of the direction when a robot adopts the direction of the strongest intensity of the signal as the direction of the nearest neighbor because we expect this approach makes the robot swarm more simple and scalable. The computer simulations show the case of the success.

Lymphatic imaging: focus on imaging probes.

In view of the importance of sentinel lymph nodes (SLNs) in tumor staging and patient management, sensitive and accurate imaging of SLNs has been intensively explored. Along with the advance of the imaging technology, various contrast agents have been developed for lymphatic imaging. In this review, the lymph node imaging agents were summarized into three groups: tumor targeting agents, lymphatic targeting agents and lymphatic mapping agents. Tumor targeting agents are used to detect metastatic tumor tissue within LNs, lymphatic targeting agents aim to visualize lymphatic vessels and lymphangionesis, while lymphatic mapping agents are mainly for SLN detection during surgery after local administration. Coupled with various signal emitters, these imaging agents work with single or multiple imaging modalities to provide a valuable way to evaluate the location and metastatic status of SLNs.

A method of enclosing a target by robot swarm with limited range homogeneous signal emitter

This paper presents a robot swarm model to enclose a target. The robots use information of the target and each of their neighbors. Every robot has its own, standard torch-­‐like signal emitter and they can observe the sum of the intensity of their torches. In this paper, the robots identify their nearest neighbor by choosing the emitting source with the strongest intensity. We expect that this new approach makes the robot swarm more simple and scalable. We confirm this model by computer simulations.

Effect of a sloping bottom on sound propagation

The paper presents the results of field measurements of acoustic fields generated in autumn hydrological conditions of the Sea of Japan shelf by a TON-320Hz autonomous signal emitter, moored in the sea at a depth of 34 m, as well as by a low-frequency pulsed pneumoemitter lowered from from a ship to a horizon of 10 m. Reception was via a hydrophone moored at a depth of 41 m from a digital radio-hydroacoustic buoy and the hydrophone of an autonomous acoustic recorder lowered together with an autonomous hydrological sonde from a drifting ship. Sound propagation from these sources was simulated by a wide-angle parabolic equation taking into account the elastic properties of rocks making up the bottom, as well as by a 3-D mode parabolic equation in the adiabatic approximation for a “fluid” bottom.

Hybrid triboelectric nanogenerator for harvesting water wave energy and as a self-powered distress signal emitter

In this paper, a hybrid triboelectric nanogenerator (TENG) has been developed for simultaneously harvesting the electrostatic energy and mechanical impact energy from water wave. It is comprised of two parts: an interfacial electrification enabled TENG (IE-TENG) and an impact-TENG. The IE-TENG, composed of a fluorinated ethylene propylene thin film and an array of electrodes underneath, is used to harvest electrostatic energy arising from the water-solid interface. The impact-TENG, constructed with nanostructured polytetrafluoroethylene (PTFE) thin films and elastic wavy electrodes, is used to scavenge the mechanical impact energy from water wave. Under water waves propagating at a speed of 0.5m/s, the short-circuit current of the IE-TENG and impact-TENG can reach 5.1µA and 4.3µA, respectively, which is able to drive nearly 50 LEDs simultaneously. Considering that natural water bodies may contain minerals and salt, the influence of NaCl concentration on the electric output of device has been investigated. Moreover, the hybrid TENG was developed as a self-powered distress signals emitter that may be used for life saving in water landing or swimming in evening. Considering the scalability of this technology, this work demonstrates the great potential of TENG in areas of hydropower harvesting, environmental monitoring and maritime search and rescue.

Least Favorable Distributions for the Design of Randomly Deployed Sensor Detection Systems

The design of a detection system in which sensors are randomly located to detect a low-power signal emitter in a random location tends to be difficult because the measurements are conditionally dependent in general and the alternative hypothesis is composite. It is shown that there are conditions that allow a system designer to deal with these problems by assuming a least favorable distribution for the emitter location that not only makes the alternative hypothesis simple and ensures a detection performance, but also causes the measurements to become conditionally i.i.d., making models more amenable for analysis. Since a design based on a least favorable distribution may be considered too conservative, this paper proposes the use of a most favorable distribution for the emitter location and uses the theory of asymptotic relative efficiency (ARE) to evaluate how conservative the design based on a least favorable distribution is. It is further shown that, if the system designer can place sensors in an enlarged deployment region, then there are situations in which the design based on a least favorable distribution becomes less and less conservative as the dimensions of the region of interest increase.

Radar Emitter Signals Recognition and Classification with Feedforward Networks

A possible application of neural networks for timely and reliable recognition of radar signal emitters is investigated. In particular, a large data set of intercepted generic radar signal samples is used for investigating and evaluating several neural network topologies, training parameters, input and output coding and machine learning facilitating data transformations. Three case studies are discussed, where in the first two the radar signals are classified in two broad classes – with civil or military application, based on patterns in their pulse train characteristics and in the third one trained to distinguish between several more specific radar functions. Very competitive results of about 82%, 84% and 67% are achieved on the testing data sets.

Processing of Instantaneous Angular Speed Signal for Detection of a Diesel Engine Failure

Continuous monitoring of diesel engine performance under its operating is critical for the prediction of malfunction development and subsequently functional failure detection. Analysis of instantaneous angular speed (IAS) of the crankshaft is considered as one of the nonintrusive and effective methods of the detection of combustion quality deterioration. In this paper results of experimental verification of fuel system's malfunction detecting, using optical encoder for IAS recording are presented. The implemented method relies on the comparison of measurement results, recorded under healthy and faulty conditions of the engine. Elaborated dynamic model of angular speed variations enables us to build templates of engine behavior. Recorded during experiment, values of cylinder pressure were taken for the approximation of pressure basic waveform. The main task of data processing is smoothing the raw angular speed signal. The noise is due to sensor mount vibrations, signal emitter machining, engine body vibrations, and crankshaft torsional vibrations. Smoothing of the measurement data was carried out by the implementation of the Savitzky-Golay filter. Measured signal after smoothing was compared with the model of IAS run.

Natural genome diversity of AI-2 quorum sensing in Escherichia coli: conserved signal production but labile signal reception.

Quorum sensing (QS) regulates the onset of bacterial social responses in function to cell density having an important impact in virulence. Autoinducer-2 (AI-2) is a signal that has the peculiarity of mediating both intra- and interspecies bacterial QS. We analyzed the diversity of all components of AI-2 QS across 44 complete genomes of Escherichia coli and Shigella strains. We used phylogenetic tools to study its evolution and determined the phenotypes of single-deletion mutants to predict phenotypes of natural strains. Our analysis revealed many likely adaptive polymorphisms both in gene content and in nucleotide sequence. We show that all natural strains possess the signal emitter (the luxS gene), but many lack a functional signal receptor (complete lsr operon) and the ability to regulate extracellular signal concentrations. This result is in striking contrast with the canonical species-specific QS systems where one often finds orphan receptors, without a cognate synthase, but not orphan emitters. Our analysis indicates that selection actively maintains a balanced polymorphism for the presence/absence of a functional lsr operon suggesting diversifying selection on the regulation of signal accumulation and recognition. These results can be explained either by niche-specific adaptation or by selection for a coercive behavior where signal-blind emitters benefit from forcing other individuals in the population to haste in cooperative behaviors.

One if by land, two if by sea: signalling to the ranks with CSP and XIP

In many streptococci, quorum sensing utilizes secreted, linear peptides that engage cognate receptors to coordinate gene expression among members of a local population. Streptococcus mutans employs the secreted peptides CSP and XIP to stimulate production of antimicrobial bacteriocins and to induce development of competence for genetic transformation. Recent progress in the field reveals that these pathways not only monitor the presence of signal emitters but also sense environmental factors. Both kinds of information are integrated by regulatory networks that then generate multiple outcomes, even among parallel cells growing in identical conditions. In this issue of Molecular Microbiology, Son and co-workers investigate how two medium types shape cellular responses to CSP and XIP pheromones in individuals across a population. Their findings characterize restrictive properties of media differing in peptidic fragment content and reveal unusual signalling properties that contribute to bimodal responses of gene expression.

Progress in high-throughput assays of MGMT and APE1 activities in cell extracts

DNA repair activity is of interest as a potential biomarker of individual susceptibility to genotoxic agents. In view of the current trend for exploitation of large cohorts in molecular epidemiology projects, there is a pressing need for the development of phenotypic DNA repair assays that are high-throughput, very sensitive, inexpensive and reliable.Towards this goal we have developed and validated two phenotypic assays for the measurement of two DNA repair enzymes in cell extracts: (1) O6-methylguanine-DNA-methyltransferase (MGMT), which repairs the O6-alkylguanine-type of adducts induced in DNA by alkylating genotoxins; and (2) apurinic/apyrimidinic endonuclease 1 (APE 1), which participates in base excision repair (BER) by causing a rate-limiting DNA strand cleavage 5′ to the abasic sites.The MGMT assay makes use of the fact that: (a) the enzyme works by irreversibly transferring the alkyl group from the O6 position of guanine to a cystein residue in its active site and thereby becomes inactivated and (b) that the free base O6-benzylguanine (BG) is a very good substrate for MGMT. In the new assay, cell extracts are incubated with BG tagged with biotin and the resulting MGMT-BG-biotin complex is immobilized on anti-MGMT-coated microtiter plates, followed by quantitation using streptavidin-conjugated alkaline phosphatase and a chemiluminescence-producing substrate.A one-step/one-tube phenotypic assay for APE1 activity has been developed based on the use of a fluorescent molecular beacon (partially self-complementary oligonucleotide with a hairpin-loop structure carrying a fluorophore and a quencher at each end). It also contains a single tetrahydrofuran residue (THF) which is recognized and cleaved by APE1, and the subsequently formed single-stranded oligomer becomes a fluorescence signal emitter. Both assays are highly sensitive, require very small amounts of protein extracts, are relatively inexpensive and can be easily automated. They have been extensively validated and are being used in the context of large-scale molecular epidemiology studies.