Odorant Binding Changes the Electrical Properties of Olfactory Receptors at the Nanoscale

The transduction of odorant binding into cellular signaling by olfactory receptors (ORs) is not understood and knowing its mechanism would enable developing new pharmacology and biohybrid electronic detectors of volatile organic com-pounds bearing high sensitivity and selectivity. The electrical characterization of ORs in bulk experiments is subject to microscopic models and assumptions. We have directly determined the nanoscale electrical properties of ORs immobilized in a fixed orientation, and their change upon odorant binding, using electrochemical scanning tunneling microscopy (EC-STM) in near-physiological conditions. Recordings of current versus time, distance, and electrochemical potential allows determining the OR impedance parameters and their dependence with odorant binding. Our results allow validating OR structural-electrostatic models and their functional activation processes.

Tunable square waveguide polarizer with irises and posts

Polarization signal processing is widely used in modern information and telecommunication systems for various purposes. Signal polarization processing is carried out in polarization-adaptive antenna systems. The key element of such systems is transformation devices for polarization processing. They perform the transformation of the types of polarization and separate the different types. The most commonly applied systems are the ones using a single circular polarization or two orthogonal circular polarizations simultaneously.The absence of the need for an accurate angle orientation between the transmitting and receiving antennas to establish communication is one of the basic advantages of this type of polarization. When using antenna systems with linear polarization, signal losses appear due to inconsistency in the orientation of the polarization planes of the transmitting and receiving antennas. This feature of circular polarization is important for satellite and many other telecommunications systems. In such systems it is difficult to maintain a fixed orientation of one antenna relative to the other. In addition, circular polarization is used to communicate with satellites orbiting the direction of the radio link. Regardless of antenna orientation, when using circular polarization, the received signal level is constant. These advantages explain why circular polarized antennas are widely used in radio engineering systems for various purposes. The paper presents the results of the development of a polarization device based on a square waveguide with two posts and two diaphragms in the frequency range from 7,7 to 8,5 GHz. The article contains the results of calculations using the developed mathematical model of the device. In addition, the results of modeling the device using the finite element method are presented for comparison. A comparison was made of the polarization characteristics and the match of the developed polarizer. The created mathematical model makes it possible to effectively analyze the characteristics when changing design parameters. These parameters include the size of the wall of the square waveguide, the heights of the diaphragms and pins, the distance between them, the thickness of the diaphragms and pins. The developed polarizer is suggested for the application in satellite telecommunication and radar systems.

Angle change of the A-domain in a single SERCA1a molecule detected by defocused orientation imaging

The sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) transports Ca2+ ions across the membrane coupled with ATP hydrolysis. Crystal structures of ligand-stabilized molecules indicate that the movement of actuator (A) domain plays a crucial role in Ca2+ translocation. However, the actual structural movements during the transitions between intermediates remain uncertain, in particular, the structure of E2PCa2 has not been solved. Here, the angle of the A-domain was measured by defocused orientation imaging using isotropic total internal reflection fluorescence microscopy. A single SERCA1a molecule, labeled with fluorophore ReAsH on the A-domain in fixed orientation, was embedded in a nanodisc, and stabilized on Ni–NTA glass. Activation with ATP and Ca2+ caused angle changes of the fluorophore and therefore the A-domain, motions lost by inhibitor, thapsigargin. Our high-speed set-up captured the motion during EP isomerization, and suggests that the A-domain rapidly rotates back and forth from an E1PCa2 position to a position close to the E2P state. This is the first report of the detection in the movement of the A-domain as an angle change. Our method provides a powerful tool to investigate the conformational change of a membrane protein in real-time.

Dynamic Optimization Self-adaptive AI Controller for a Four-wheel Independent Drive Electric Rover

In this paper, a dynamic optimization self-adaptive controller for a four-wheel independent drive electric rover has been investigated to enhance the dynamic stability. The proposed self-adaptive AI controller is based on dynamic Fuzzy Logic (FL) control mechanism. The dynamic self-adaptive properties have been integrated into the proposed FL controller through a dynamically tuned Particle Swarm Optimization (PSO) mechanism. Nevertheless, the dynamic FL controller and the dynamic PSO mechanism has been synchronized together for every sampling instance k to obtain the optimum performance of the electric rover. In this electric rover, all the four wheels have a fixed orientation and each wheel powered by a 250-Watt Brushless Direct Current (BLDC) motor through separate gear ratio mechanisms to obtain the desired torque and angular velocity. Therefore, the steering mechanism was achieved in this rover through the proposed AI controller, which was based on the differential speed mechanism. However, this paper presents the control methodology and obtained test results related to straight road tests under different slippery road conditions. The rover test results show that on different slippery road conditions the proposed PSO based FL controller has maintained the wheel slip ratio of all the four wheels which was less than 0.35 approximately. Here, the translational speed has been limited to 40 km/hr approximately within its recorded top speed of 90 km/hr while maintaining the desired fix orientation.

Integrated sample-handling and mounting system for fixed-target serial synchrotron crystallography

Serial synchrotron crystallography (SSX) is enabling the efficient use of small crystals for structure–function studies of biomolecules and for drug discovery. An integrated SSX system has been developed comprising ultralow background-scatter sample holders suitable for room and cryogenic temperature crystallographic data collection, a sample-loading station and a humid `gloveless' glovebox. The sample holders incorporate thin-film supports with a variety of designs optimized for different crystal-loading challenges. These holders facilitate the dispersion of crystals and the removal of excess liquid, can be cooled at extremely high rates, generate little background scatter, allow data collection over >90° of oscillation without obstruction or the risk of generating saturating Bragg peaks, are compatible with existing infrastructure for high-throughput cryocrystallography and are reusable. The sample-loading station allows sample preparation and loading onto the support film, the application of time-varying suction for optimal removal of excess liquid, crystal repositioning and cryoprotection, and the application of sealing films for room-temperature data collection, all in a controlled-humidity environment. The humid glovebox allows microscope observation of the sample-loading station and crystallization trays while maintaining near-saturating humidities that further minimize the risks of sample dehydration and damage, and maximize working times. This integrated system addresses common problems in obtaining properly dispersed, properly hydrated and isomorphous microcrystals for fixed-orientation and oscillation data collection. Its ease of use, flexibility and optimized performance make it attractive not just for SSX but also for single-crystal and few-crystal data collection. Fundamental concepts that are important in achieving desired crystal distributions on a sample holder via time-varying suction-induced liquid flows are also discussed.

Compression of High-Resolution Satellite Images Using Optical Image Processing

This chapter presents a novel method for compressing satellite imagery using phase grating to facilitate the optimization of storage space and bandwidth in satellite communication. In this research work, each Satellite image is first modulated with high grating frequency in a fixed orientation. Due to this modulation, three spots (spectrum) have been generated. From these three spots, by applying Inverse Fourier Transform in any one band, we can recover the image. Out of these three spots, one is center spectrum spot and other spots represent two sidebands. Care should be taken during the spot selection is to avoid aliasing effect. At the receiving end, to recover image we use only one spectrum. We have proved that size of the extracted image is less than the original image. In this way, compression of satellite image has been performed. To measure quality of the output images, PSNR value has been calculated and compared this value with previous techniques. As high-resolution satellite image contains a lot of information, therefore to get detail information from extracted image, compression ratio should be as minimum as possible.

Evaluation of head-tracked binaural auralizations of speech signals generated with a virtual artificial head in anechoic and classroom environments

In order to realize binaural auralizations with head tracking, BRIRs of individual listeners are needed for different head orientations. In this contribution, a filter-and-sum beamformer, referred to as virtual artificial head (VAH), was used to synthesize the BRIRs. To this end, room impulse responses were first measured with a VAH, using a planar microphone array with 24 microphones, for one fixed orientation, in an anechoic and a reverberant room. Then, individual spectral weights for 185 orientations of the listener’s head were calculated with different parameter sets. Parameters included the number and the direction of the sources considered in the calculation of spectral weights as well as the required minimum mean white noise gain (WNGm). For both acoustical environments, the quality of the resulting synthesized BRIRs was assessed perceptually in head-tracked auralizations, in direct comparison to real loudspeaker playback in the room. Results showed that both rooms could be auralized with the VAH for speech signals in a perceptually convincing manner, by employing spectral weights calculated with 72 source directions from the horizontal plane. In addition, low resulting WNGm values should be avoided. Furthermore, in the dynamic binaural auralization with speech signals in this study, individual BRIRs seemed to offer no advantage over non-individual BRIRs, confirming previous results that were obtained with simulated BRIRs.

Singularity analysis and avoidance of a planar parallel mechanism with kinematic redundancy under a fixed orientation

In this paper, the singularity of a planar mechanism with kinematic redundancy is studied. First, the architecture of the mechanism and the concept schematic diagram for singularity avoidance are stated. Next, inverse kinematics model of the planar parallel mechanism with kinematic redundancy is established. For determining the unique inverse solution of the mechanism under certain initial installation configuration, a comparison analysis based on the strategy tree and the virtual prototype is performed. Then, based on the obtained Jacobian matrices and the singular condition, the workspace-singularity map and two singular configurations of the mechanism are drawn. Finally, with the obtained workspace-singularity map, a singularity-free transition layer and an aisle can be found to perform to singularity avoidance, even if the initial designed trajectory passing through the second kind of singularity. Three tasks are carried out to illustrate that the workspace boundary and singular configuration can be changed by adjusting the kinematic redundant actuated parameter.

Chiroptical spectroscopy of a freely diffusing single nanoparticle

Chiral plasmonic nanoparticles can exhibit strong chiroptical signals compared to the corresponding molecular response. Observations are, however, generally restricted to measurements on stationary single particles with a fixed orientation, which complicates the spectral analysis. Here, we report the spectroscopic observation of a freely diffusing single chiral nanoparticle in solution. By acquiring time-resolved circular differential scattering signals we show that the spectral interpretation is significantly simplified. We experimentally demonstrate the equivalence between time-averaged chiral spectra observed for an individual nanostructure and the corresponding ensemble spectra, and thereby demonstrate the ergodic principle for chiroptical spectroscopy. We also show how it is possible for an achiral particle to yield an instantaneous chiroptical response, whereas the time-averaged signals are an unequivocal measure of chirality. Time-resolved chiroptical spectroscopy on a freely moving chiral nanoparticle advances the field of single-particle spectroscopy, and is a means to obtain the true signature of the nanoparticle’s chirality.