Complex Modulation Research Articles

Heart Rate Complexity and Autonomic Modulation Are Associated with Psychological Response Inhibition in Healthy Subjects

the ability to suppress/regulate impulsive reactions has been identified as common factor underlying the performance in all executive function tasks. We analyzed the HRV signals (power of high (HF) and low (LF) frequency, Sample Entropy (SampEn), and Complexity Index (CI)) during the execution of cognitive tests to assess flexibility, inhibition abilities, and rule learning. we enrolled thirty-six healthy subjects, recording five minutes of resting state and two tasks of increasing complexity based on 220 visual stimuli with 12 × 12 cm red and white squares on a black background. at baseline, CI was negatively correlated with age, and LF was negatively correlated with SampEn. In Task 1, the CI and LF/HF were negatively correlated with errors. In Task 2, the reaction time positively correlated with the CI and the LF/HF ratio errors. Using a binary logistic regression model, age, CI, and LF/HF ratio classified performance groups with a sensitivity and specificity of 73 and 71%, respectively. this study performed an important initial exploration in defining the complex relationship between CI, sympathovagal balance, and age in regulating impulsive reactions during cognitive tests. Our approach could be applied in assessing cognitive decline, providing additional information on the brain-heart interaction.

Random-modulated pulse lidar using a gain-switched semiconductor laser with a delayed self-homodyne interferometer.

We propose the generation of random-modulated pulses using a gain-switched semiconductor laser with a delayed self-homodyne interferometer (DSHI) for lidar applications. By emitting non-repetitive random-modulated pulses, ambiguity in ranging and interference in detection can be mitigated. When gain-switched, the wavelength of the laser fluctuates abruptly at the beginning of the pulse and then drops until it stabilizes toward its continuous-wave (CW) state. By beating the two pulses with instantaneous frequency detuning from the DSHI, pulses consisting of random and down-chirped modulations can be generated without any complex code generation and modulation. In this study, we investigate the waveforms and spectra of the random-modulated pulses generated under various homodyne delay lengths, switching currents, and pulsewidths. We characterize their signal-to-noise ratio (SNR), precision, and cross-correlation between consecutive pulses to evaluate their performance in lidar applications. For a good SNR of over 12 dB, the generated pulses have an optimal precision of approximately 1 mm in ranging, which is substantially better than the chaos-modulated pulses generated based on laser feedback dynamics. By establishing a random-modulated pulse lidar based on the proposed gain-switched homodyne scheme, we successfully demonstrate 3D imaging and profiling with good precision.

A thermo-mechanical coupling model for simulating the re-entry failure evolution mechanism of spacecraft propulsion module

A three-dimensional dynamic thermo-mechanical coupling model (TMCM) has been developed to analyze re-entry evolution mechanism of spacecraft propulsion module subjected to aerodynamic/thermal loads. Firstly, a general dynamic thermo-mechanical coupling finite element algorithm is proposed based on TMCM. The accuracy of TMCM is verified by comparison with analytical solutions of one-dimensional problem and numerical solutions of three-dimensional problem. Then, the TMCM for a complex propulsion module is established, in which all the fuel tanks, gas cylinders, support frame and cone platform are taken into account. The external heat flux and pressure of the whole propulsion module are calculated by gas-kinetic unified algorithm (GKUA). Finally, the dynamic thermo-mechanical evolution mechanism of each component structure and the influence of radiation heat transfer are discussed separately during re-entry 90 km-75 km altitude range, and materials considered are stainless steel, carbon fiber composite and aluminum alloy. Simulation results reveal the evolution process of the temperature field, displacement field and stress field of the whole propulsion module. The TMCM provides a powerful tool for accurate prediction of disintegration failure during spacecraft re-entry through thermal and structural analysis of the structure.

Reaction-based energy level modulation of a cyclometalated iridium complex for electrochemiluminescent detection of formaldehyde.

Formaldehyde is a toxic compound present in both the environment and living systems, and its detection is important due to its association with various pathological process. In this study, we report a new electrochemiluminescence (ECL) probe based on a cyclometalated iridium complex (IrHAA) for the selective detection of formaldehyde. The homoallylamine moiety in IrHAA reacts with formaldehyde, undergoing a 2-aza-Cope-rearrangement reaction to form a formyl group. Significant changes in the electronic properties and molecular orbital energies of the iridium complex through the functional group transformation result in enhanced ECL and radiometric phosphorescence changes, enabling the quantitative and selective detection of formaldehyde. The energetic requirements for ECL sensing were investigated, highlighting the importance of the excited state energy for achieving efficient ECL. The sensing mechanism was elucidated using NMR spectroscopy and MALDI-TOF analysis.

ISAR Imaging of Precession Target Based on Joint Constraints of Low Rank and Sparsity of Tensor

Precession is a typical form of micro-motion that can bring about complex and time-varying Doppler modulation. The range instantaneous Doppler (RID) method, which uses time-frequency analysis instead of the Fourier transform to describe the time-varying Doppler, is typically used to obtain the high-resolution inverse synthetic aperture radar (ISAR) image of a precession target. However, the observation time of a specific target is often non-uniform due to various interference and channel switching among multi-channel radars, which will lead to a sparse aperture. Sparse aperture can cause sidelobe interference in the ISAR image obtained by the RID method, making it difficult to focus well. To solve the problem whereby the RID method fails to image a precession target with sparse aperture, this paper proposes a new method based on the joint constraints of low-rank and sparsity of tensor, and uses the alternating direction method of multipliers to solve the problem. The low-rank can constrain the correlation among consecutive ISAR images, and sparsity can remove the impact of sparse aperture. This effectively eliminates the micro-Doppler interference and sidelobe interference in ISAR image, and enables the reconstruction of precession target in a sequence of ISAR images with sparse aperture. Experimental results under both simulations and darkroom measurements verify that the proposed method performs well on ISAR images of conic precession target with sparse aperture.

Control of sodium and potassium homeostasis by renal distal convoluted tubules.

Distal convoluted tubules (DCT), which contain the Na-Cl cotransporter (NCC) inhibited by thiazide diuretics, undergo complex modulation to preserve Na+ and K+ homeostasis. The lysine kinases 1 and 4 (WNK1 and WNK4), identified as hyperactive in the hereditary disease pseudohypoaldosteronism type 2, are responsible for activation of NCC and consequent hypokalemia and hypertension. WNK4, highly expressed in DCT, activates the SPAK/OSR1 kinases, which phosphorylate NCC and other regulatory proteins and transporters in the distal nephron. WNK4 works as a chloride sensor through a Cl- binding site, which acts as an on/off switch at this kinase in response to changes of basolateral membrane electrical potential, the driving force of cellular Cl- efflux. High intracellular Cl- in hyperkalemia decreases NCC phosphorylation and low intracellular Cl- in hypokalemia increases NCC phosphorylation and activity, which makes plasma K+ concentration a central modulator of NCC and of K+ secretion. The WNK4 phosphorylation by cSrc or SGK1, activated by angiotensin II or aldosterone, respectively, is another relevant mechanism of NCC, ENaC, and ROMK modulation in states such as volume reduction, hyperkalemia, and hypokalemia. Loss of NCC function induces upregulation of electroneutral NaCl reabsorption by type B intercalated cells through the combined activity of pendrin and NDCBE, as demonstrated in double knockout mice (KO) animal models, Ncc/pendrin or Ncc/NDCBE. The analysis of ks-Nedd-4-2 KO animal models introduced the modulation of NEDD4-2 by intracellular Mg2+ activity as an important regulator of NCC, explaining the thiazide-induced persistent hypokalemia.

Dual-Band 28- and 39-GHz Phased Arrays for Multistandard 5G Applications

This article presents a 32-element 28/39-GHz dual-band phased array for fifth-generation (5G) communication systems. The array is based on separate sets of SiGe transmit/ receive (Tx/Rx) beamformer chips to realize independent dual-beamforming capabilities at orthogonal linear polarizations. The beamformer chips are integrated with an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8 \times 4$ </tex-math></inline-formula> dual-band stacked patch antenna array on a low-cost printed circuit board (PCB) and grouped together using two different Wilkinson networks to form two separate beamforming systems. The dual-band array demonstrates a measured effective isotropic radiated power (EIRP) of 40–42 dBm at the 28- and 39-GHz bands. The array is capable of scanning ±55° in the 28-GHz band and ±40° in the 39-GHz band, both in the azimuth plane. In simultaneous dual-frequency dual-beam operation with the 28-GHz band on the V-pol. and the 39-GHz band on the H-pol., spectrum measurement shows that the array has no visible intermodulation products between the 28- and 39-GHz beams. Also, complex modulation measurements with 64-QAM waveforms show < 3% error vector magnitude (EVM) at an EIRP of up to 36-dBm EIRP for both beams radiating together and without interference with each other. This work demonstrates the first millimeter-wave (mm-wave) 5G dual-band array and paves the way toward multistandard systems.

HSF1 expression in tumor-associated macrophages promotes tumor cell proliferation and indicates poor prognosis in esophageal squamous cell carcinoma.

Tumor-associated macrophages (TAMs), are crucial for the survival and development of tumor cells. Heat shock factor 1 (HSF1) is a potent, complex carcinogenesis modulator, and esophageal cancer (EC) patients have a bad prognosis when HSF1 is highly expressed. HSF1's clinical importance and biological role in TAMs are still unknown. The HSF1 expression profile and patient survival information were analyzed from the TCGA database. The infiltration of different types of immune cells in EC was evaluated based on HSF1 gene expression by Sangerbox 3.0. Immunochemistry was employed to assess HSF1 protein expression in 134 individuals with esophageal squamous cell carcinoma (ESCC), proceeded by association with clinicopathological variables. The role of macrophage-driven HSF1 were observed using HSF1-knockdown THP1 cells. High level of HSF1 have a poorer prognosis in individuals with EC. The expressing level of HSF1 was positively related to infiltration of M2 macrophages (P < 0.05). The expression of HSF1 in macrophages was an independent factor for DFS (P = 0.002) and OS (P = 0.002) in ESCC cases. HSF1 was up-regulated in IL-4 stimulation THP1 cells in a time-dependent manner. Under the heat stimulation condition, THP1-derived macrophages were more sensitive than tumor cells. Compared to IL-4 induced-THP1 cells control, the HSF1 knockdown in THP1 cell inhibited the growth and proliferation of ESCC cells. The up-regulation of HSF1 was more rapid and could affect the proliferation of tumor cells in IL4-induced macrophages. The expression of HSF1 in TAMs can also serve as a marker for ESCC prognosis.

Cryo-EM structure of the respiratory I + III2 supercomplex from Arabidopsis thaliana at 2 Å resolution

Protein complexes of the mitochondrial respiratory chain assemble into respiratory supercomplexes. Here we present the high-resolution electron cryo-microscopy structure of the Arabidopsis respiratory supercomplex consisting of complex I and a complex III dimer, with a total of 68 protein subunits and numerous bound cofactors. A complex I-ferredoxin, subunit B14.7 and P9, a newly defined subunit of plant complex I, mediate supercomplex formation. The component complexes stabilize one another, enabling new detailed insights into their structure. We describe (1) an interrupted aqueous passage for proton translocation in the membrane arm of complex I; (2) a new coenzyme A within the carbonic anhydrase module of plant complex I defining a second catalytic centre; and (3) the water structure at the proton exit pathway of complex III2 with a co-purified ubiquinone in the QO site. We propose that the main role of the plant supercomplex is to stabilize its components in the membrane.

Wrk-1 and rig-5 control pioneer and follower axon navigation in the ventral nerve cord of Caenorhabditis elegans in a nid-1 mutant background.

During nervous system development, neurons send out axons, which must navigate large distances to reach synaptic targets. Axons grow out sequentially. The early outgrowing axons, pioneers, must integrate information from various guidance cues in their environment to determine the correct direction of outgrowth. Later outgrowing follower axons can at least in part navigate by adhering to pioneer axons. In Caenorhabditis elegans, the right side of the largest longitudinal axon tract, the ventral nerve cord, is pioneered by the AVG axon. How the AVG axon navigates is only partially understood. In this study, we describe the role of two members of the IgCAM family, wrk-1 and rig-5, in AVG axon navigation. While wrk-1 and rig-5 single mutants do not show AVG navigation defects, both mutants have highly penetrant pioneer and follower navigation defects in a nid-1 mutant background. Both mutations increase the fraction of follower axons following the misguided pioneer axon. We found that wrk-1 and rig-5 act in different genetic pathways, suggesting that we identified two pioneer-independent guidance pathways used by follower axons. We assessed general locomotion, mechanosensory responsiveness, and habituation to determine whether axonal navigation defects impact nervous system function. In rig-5 nid-1 double mutants, we found no significant defects in free movement behavior; however, a subpopulation of animals shows minor changes in response duration habituation after mechanosensory stimulation. These results suggest that guidance defects of axons in the motor circuit do not necessarily lead to major movement or behavioral defects but impact more complex behavioral modulation.

DEVELOPMENT OF ONBOARD CONTROL SYSTEM ARCHITECTURE FOR NANOSATELLITES

This article presents development of the architecture of the onboard control system. In particular, the hardware and circuit solutions in the development of the module are presented. Technical solutions, the concept of the mechanical layout of the onboard control system and block diagrams of the presented modules of the onboard complex are also discussed. Main functions of the on-board software are described in details, which will help in design and development of ultra-small artificial satellites. This article serves as a new approach for how to effectively configure and operate the on-board control system.

EVALUATION OF PATIENT-SPECIFIC IMRT QUALITY ASSURANCE AND POINT DOSE MEASUREMENT FOR COMPLEX HEAD AND NECK AND BRAIN CANCER USING GAFCHROMIC EBT3 FILM.

Patient-specific intensity-modulated radiation therapy (IMRT) quality assurance (QA) is essential for complex radiotherapy treatment as it involves complex intensity modulation and high-dose gradient regions. IMRT QA was performed by point dose verification and two-dimensional (2D) dose distribution measurement using gamma method. Calibrated External Beam Therapy 3 (EBT3) film was used for point dose and pre-treatment verification of 10 IMRT plans, five complex Head and Neck (HN) and five brain cases. The gamma passing rate (GPR) was evaluated for 3%/3mm gamma criteria and compared with 2D array. Isocentre dose was measured for all 10 IMRT plans on EBT3 film. Percentage deviation of point dose measurement from TPS calculated was found 0.4% for brain cases and 2.9% for HN cases. The GPR for 3%/3mm criteria was obtained higher than 95% for brain and HN cases. Results suggest that film dosimetry is also a reliable verification system for patient-specific IMRT QA as the 2D array.

Design and analysis of passive variable-pitch propeller for VTOL UAVs

The design requirements for the propellers of vertical take-off and landing (VTOL) UAVs are contradictory in the cruise phase and VTOL phase. To alleviate the contradiction, the concept of passive variable-pitch propeller (PVPP) using the aerodynamic moment to change the pitch was proposed by previous researchers, which can adaptively adjust the pitch as the advance ratio changes. However, this type of PVPP has not been widely used due to its complex balance module. This paper constructs a new framework to design such PVPP to simplify its balance module and increase its utility. We proposed new methods to parameterize the shape of PVPP and established mathematical models for each optimization in the design process. Subsequently, a case study verified the feasibility of the design method to simplify the trim module. By optimizing the position of the blade-pivot axis, the design results can work efficiently in multiple working conditions and can also achieve the highest efficiency at a specific advance ratio, which is of practical significance for VTOL UAVs to reduce energy consumption and increase payload in mission profiles. We conducted additional analysis on the characteristics of PVPP based on two aspects: (A) the influence of the blade airfoil on the pitching moment characteristics of PVPP; (B) the comparison between the PVPP with normal layout and the PVPP with canard layout. Overall, the methodology and general rules proposed in this paper provide a theoretical basis and technical support for designing PVPP for UTOL UAVs.

Model for Prediction of Testing Time of a Computer Program for Automated Reliability Evaluation of Semiconductor Devices

The KLASS computer program planned for development is designed to work as a part of the ARION-plus software package and allows you to perform an automated assessment of the reliability of electronic products, including semiconductor devices. At the stage of work planning on the creation of the KLASS program, as a module of the ARION-plus complex, the question arose about the working time allotted for the procedure for testing a computer program. The approaches described in the scientific literature used to assess the operational reliability of computer programs, taking into account their testing, proceed from the fact that the program code has been written and debugged and there are certain data on the results of testing the computer program. Software developers would like to know the predicted testing time, which ensures a given operational reliability of a computer program, even before starting work on writing program code. Based on the analysis of the experimental data on the reliability of computer programs in various fields of application, a model is proposed for determining the testing time required to ensure the operational reliability of programs. The model was used for the computer program KLASS planned for development and takes into account the programming language, the amount of program code, the speed of the computer processor, and the scope of the program. Based on the obtained model, a nomogram with two binary fields was constructed, which allows one to quickly determine the predicted time for testing computer programs.

Evaluation and analysis of optically injection-locked semiconductor laser characteristics for optical complex signal generation

In this paper, we present an investigation of the optical injection-locked parameters which utilize an approach to creating optical complex signals using optically injection-locked (OIL) semiconductor lasers. Subsequently, we discuss the impact of the OIL parameters on the locking map, manufacturing the corresponding complex signal area, pole-zero diagram, and frequency response of the system. The steady-state analysis of the rate equations indicates that changing OIL parameters can result in simultaneous optical AM and PM of the OIL laser while preserving the injection locking state. Based on the simulation results, we found that using strong R inj and high negative Δfinj (which are mandatory for generating high-quality complex modulation) along with α = 3; can improve the performance in producing complex signal area as well as the frequency response, while using other settings does not lead to the development of both. Therefore, we achieve the maximum generated complex signal area and the -3dB frequency by using an adjusted parameter value for the system, which results in a faster modulation speed and higher quality of the optical complex modulation.

Three-dimensional structure of magnetic skyrmions

Magnetic skyrmions (skyrmions hereafter) are magnetization configurations, whose topological robustness and nanoscale size have led to speculation that they could find use as a next-generation information carrier. Skyrmions have been observed in magnetic multilayer materials that are thin compared to the radius of a skyrmion, and chiral cubic single crystals that can be far larger than any characteristic skyrmion scale. In these single crystals, one would expect that skyrmions could exhibit interesting three-dimensional (3D) characteristics. Here, the symmetry of the micromagnetic free energy is investigated. This symmetry permits a complex 3D modulation of a skyrmion string, which we show to be a requirement of a skyrmion coexisting with the conical state. We discuss the implications of this modulation with respect to Thiele's equation and interskyrmion interactions. Further to this internal modulation, we study theoretically and show experimentally that the strings themselves must contort towards the surfaces of their confining crystals.

Brewster differential microscopy

Imaging of transparent samples such as cells is important in the biomedicine field; however, insignificant absorption and weakly scattering limit the imaging contrast of phase objects. Here, we propose and demonstrate Brewster differential microscopy based on simple optical reflection at the glass interface. The combination of spin–orbit interaction of light and the Brewster effect can perform two-dimensional differentiation to the incident light distribution and, thus, achieves isotropic edge-enhanced imaging of pure phase objects, which overcomes the limitation of traditional one-dimensional imaging. Furthermore, by introducing bias retardation, we also reconstruct the original phase distribution. The proposed microscopic imaging mechanism does not involve any complex modulation devices and takes advantages of simple and low-cost structure. The results indicate that our research shows promising applications for nondestructive imaging of biological cells.

Structural and conformational analysis of HSP60-derived peptides as a TLR4/MD2 complex modulator: An in silico and in vitro approach

Structural and conformational analysis of HSP60-derived peptides as a TLR4/MD2 complex modulator: An in silico and in vitro approach

Accurate Low Complex Modulation Format and Symbol Rate Identification for Autonomous Lightpath Operation

Network automation promises to reduce costs while guaranteeing the required performance; this is paramount when dealing with the forecasted highly dynamic traffic that will be generated by new 5G/6G applications. In optical networks, autonomous lightpath operation entails that the optical receiver can identify the configuration of a received optical signal without necessarily being configured from the network controller. This provides relief for the network controller from real-time operation, and it can simplify the operation in multi-domain scenarios, where an optical connection spans across more than one domain. Consequently, in this work, we propose a blind and low complex modulation format (MF) and symbol rate (SR) identification algorithm. The algorithm is based on studying the effects of decoding an optical signal with different MFs and SRs. Extensive MATLAB-based simulations have been carried out which consider a coherent wavelength division multiplexed system based on 32 and 64 quadrature amplitude modulated signals at up to 96 GBd, thus enabling bit rates of up to 800 Gb/s/channel. The results show remarkable identification accuracy in the presence of linear and nonlinear noise for a wide range of feasible configurations.

Dynamic complex opto-magnetic holography

Despite recent significant progress in real-time, large-area computer-generated holography, its memory requirements and computational loads will be hard to tackle for several decades to come with the current paradigm based on a priori calculations and bit-plane writing to a spatial light modulator. Here we experimentally demonstrate a holistic approach to serial computation and repeatable writing of computer-generated dynamic holograms without Fourier transform, using minimal amounts of computer memory. We use the ultrafast opto-magnetic recording of holographic patterns in a ferrimagnetic film with femtosecond laser pulses, driven by the on-the-fly hardware computation of a single holographic point. The intensity-threshold nature of the magnetic medium allows sub-diffraction-limited, point-by-point toggling of arbitrarily localized magnetic spots on the sample, according to the proposed circular detour-phase encoding, providing complex modulation and symmetrical suppression of upper diffractive orders and conjugated terms in holographically reconstructed 3-D images.