Transmission Of Modulated Signals Research Articles

Extracellular Vesicles: The Next Generation of Biomarkers and Treatment for Central Nervous System Diseases.

It has been widely established that the characterization of extracellular vesicles (EVs), particularly small EVs (sEVs), shed by different cell types into biofluids, helps to identify biomarkers and therapeutic targets in neurological and neurodegenerative diseases. Recent studies are also exploring the efficacy of mesenchymal stem cell-derived extracellular vesicles naturally enriched with therapeutic microRNAs and proteins for treating various diseases. In addition, EVs released by various neural cells play a crucial function in the modulation of signal transmission in the brain in physiological conditions. However, in pathological conditions, such EVs can facilitate the spread of pathological proteins from one brain region to the other. On the other hand, the analysis of EVs in biofluids can identify sensitive biomarkers for diagnosis, prognosis, and disease progression. This review discusses the potential therapeutic use of stem cell-derived EVs in several central nervous system diseases. It lists their differences and similarities and confers various studies exploring EVs as biomarkers. Further advances in EV research in the coming years will likely lead to the routine use of EVs in therapeutic settings.

The differential effects of blocking retinal orexin receptors on the expression of retinal c-fos and hypothalamic Vip, PACAP, Bmal1, and c-fos in Male Wistar Rats

Orexin A and B (OXA and OXB) and their receptors are expressed in the majority of retinal neurons in humans, rats, and mice. Orexins modulate signal transmission between the different layers of the retina. The suprachiasmatic nucleus (SCN) and the retina are central and peripheral components of the body's biological clocks; respectively. The SCN receives photic information from the retina through the retinohypothalamic tract (RHT) to synchronize bodily functions with environmental changes. In present study, we aimed to investigate the impact of inhibiting retinal orexin receptors on the expression of retinal Bmal1 and c-fos, as well as hypothalamic c-fos, Bmal1, Vip, and PACAP at four different time-points (Zeitgeber time; ZT 3, 6, 11, and ZT-0). The intravitreal injection (IVI) of OX1R antagonist (SB-334867) and OX2R antagonist (JNJ-10397049) significantly up-regulated c-fos expression in the retina. Additionally, compared to the control group, the combined injection of SB-334867 and JNJ-10397049 showed a greater increase in retinal expression of this gene. Moreover, the expression of hypothalamic Vip and PACAP was significantly up-regulated in both the SB-334867 and JNJ-10397049 groups. In contrast, the expression of Bmal1 was down-regulated. Furthermore, the expression of hypothalamic c-fos was down-regulated in all groups treated with SB-334867 and JNJ-10397049. Additionally, the study demonstrated that blocking these receptors in the retina resulted in alterations in circadian rhythm parameters such as mesor, amplitude, and acrophase. Finally, it affected the phase of gene expression rhythms in both the retina and hypothalamus, as identified through cosinor analysis and the zero-amplitude test. This study represents the initial exploration of how retinal orexin receptors influence expression of rhythmic genes in the retina and hypothalamus. These findings could provide new insights into how the retina regulates the circadian rhythm in both regions and illuminate the role of the orexinergic system expression within the retina.

Levels of photoactivated phototropin modulate signal transmission during the chloroplast accumulation response.

Chloroplasts accumulate in regions of plant cells exposed to irradiation to maximize light reception for efficient photosynthesis. This response is mediated by the blue-light receptor phototropin. Upon the perception of blue light, phototropin is photoactivated, an unknown signal is transmitted from the photoactivated phototropin to distant chloroplasts, and the chloroplasts begin their directional movement. How activated phototropin initiates this signal transmission is unknown. Here, using the liverwort Marchantia polymorpha, we analysed whether increased photoactive phototropin levels mediate signal transmission and chloroplast behaviour during the accumulation response. The signal transmission rate was higher in transgenic cells overexpressing phototropin than in wild-type cells. However, the chloroplast directional movement was similar between wild-type and transgenic cells. Consistent with the observation, increasing the amount of photoactivated phototropin through higher blue-light intensity also accelerated signal transmission but did not affect chloroplast behaviour in wild-type cells. Photoactivation of phototropin under weak blue-light led to the greater protein level of phosphorylated phototropin in cells overexpressing phototropin than in wild-type cells, whereas the autophosphorylation level within each phototropin molecule was similar. These results indicate that the abundance of photoactivated phototropin modulates the signal transmission rate to distant chloroplasts but does not affect chloroplast behaviour during the accumulation response.

Online digital compensation of pump dithering induced phase and amplitude distortions in transmission links with cascaded fibre-optical parametric amplifiers

We present an advanced online digital signal processing (DSP) method for correcting the phase and amplitude distortions caused by the phase modulation of the pump source and its interaction with the dispersive fibre channel in transmission systems using cascaded fibre-optical parametric amplifiers. The proposed algorithm is numerically demonstrated to achieve significant (up to 3.7 dB for a four-tone pump-phase modulation scheme) Q2-factor performance improvement over conventional DSP in 16 quadrature-amplitude modulation signal transmission.

Research progress of wearable temperature sensor based on electronic skin

The rapid development of science and technology has led to an increasing demand for new sensors, among which wearable temperature sensors based on electronic skin have played a particularly important role in artificial limbs and intelligent robots. This paper introduces the physical structure and working principle of wearable temperature sensor based on electronic skin. In this part, it focuses on two models of electrical signal changes caused by temperature changes. At the same time, the circuit structure and signal transmission and signal processing mode are also mentioned. This paper also introduces the characteristics of the material used in order to achieve direct contact with the human body. Some researchers work is also introduced, including accurate and linear reflection of temperature changes, fast response, durable use, and resistance to external interference, etc. The researchers research on the realization of the above functions is mentioned in the paper. Finally, the practical application and future prospect of this type of temperature sensor are introduced. In addition, some more mature technologies for the preparation of such wearable temperature sensors based on electronic skin are also described in this paper.

Look-Up-Table-Based Direct-Detection-Faster-Than-Nyquist-Algorithm-Enabled IM/DD Transmission with Severe Bandwidth Limitation

The emergence of new applications is driving a dramatic growth in the capacity of data center interconnects. Intensity modulation and direct detection (IM/DD) has the characteristics of low cost, low power consumption and a small footprint. Industry and academia have conducted much research on IM/DD systems as a cost-effective solution. However, optical/electronic bandwidth and fiber dispersion are the restricting factors for the improvement of transmission capacity. Pattern-dependent distortion is an important aspect that affects system performance. In this paper, we propose a look-up table (LUT)-based direct-detection-faster-than-Nyquist (DDFTN) algorithm to compensate for pattern-dependent distortion. The performances of feedforward-equalization (FFE) only, the original DDFTN, least-squares (LS)-based DDFTN, and LUT-based DDFTN algorithms in IM/DD-based 112/140 Gbit/s four-level pulse-amplitude modulation (PAM-4) signal transmission were evaluated. The experimental results indicate that LUT-based DDFTN performs better with low computational complexity.

Digital Mobile Fronthaul Based on Delta-Sigma Modulation and Chirp-Managed Signal Transmission

Digital Mobile Fronthaul Based on Delta-Sigma Modulation and Chirp-Managed Signal Transmission

Deep-Learning-Enabled Direct Detection With Reduced Computational Complexity and High Electrical-Spectral-Efficiency

Complex-valued double-sideband (CV-DSB) direct detection (DD) is a promising solution for high capacity and cost-sensitive data center interconnects, since it can reconstruct the optical field as a homodyne coherent receiver while does not require a costly local oscillator laser. In a carrier-assisted CV-DSB DD system, the carrier occupies a large proportion of the total optical signal power but bears no information. Reducing the carrier to signal power ratio (CSPR) can improve the information-bearing signal power and thus maximize the achievable system performance. Recently, we have proposed and demonstrated a deep-learning-enabled DD (DLEDD) scheme to reconstruct the full-field of the CV-DSB signal. In the DLEDD scheme, the optical CV-DSB signal was detected by a dispersion-diversity receiver and then recovered by a deep convolutional neural network (CNN). Nevertheless, the computational complexity of the deep CNN is the main obstacle to the application of the DLEDD scheme. In this paper, we demonstrate a 50-GBaud CV-DSB 32-ary quadrature amplitude modulation (32-QAM) signal transmission over 80-km single-mode fiber with ∼64% computational-budget reduction in the field reconstruction. This is achieved by using 1×1 convolutions to attain a sparse dimensionality (in particular the number of channels) of the deep CNN. To the best of our knowledge, we achieve the highest electrical spectral efficiency of 7.07 b/s/Hz per polarization per wavelength for a CV-DSB DD receiver without requiring a sharp-roll-off optical filter.

Integrated biosensing system of electrochemistry and electrophysiology for cortisol and skin conductance analysis on smartphone

High level of mental stress will lead to negative psychological and health consequences, such as insomnia, depression, and cardiovascular disease, which will increase the suicide rate and affect social stability. Mental stress has been proved to be related to biomarkers cortisol and skin conductance, and reflects the complementary advantages of stress monitoring. Based on electrochemistry and electrophysiology analysis technology, combined with microelectronic design and biosensors, this paper constructed an integrated physiological and biochemical sensing system, and an intelligent user interaction system. Firstly, a molecularly imprinted biosensor with gold nanoparticles (AuNPs), prussian blue (PB), and polypyrrole (PPy), achieved highly sensitive detection of cortisol in the range of 1–10000 ng/mL and demonstrating good specificity. The cortisol detection unit used differential pulse voltammetry (DPV) method by dual power amplifier chip AD8674, which was a precision operational amplifier with low noise, low input bias current, and unit gain stability. Then, the skin conductance detection unit was mainly composed of a pulse width modulation (PWM) drive circuit, which was designed to achieve a 100 Hz voltage output. The integrated system was designed with microcontroller module, transimpedance amplifier (TIA) module, power management module, signal transmission module, cortisol and skin conductance detection module, which was suitable for constructing precision voltage control and weak current signal conditioning. Finally, based on the software and hardware platform of smartphones, an intelligent analysis system was developed to improve the portability and user interaction convenience. Our system achieved the physiological and biochemical joint detection for the first time, showing enormous application potential in future multimode sensing monitoring.

Scheme to eliminate the time shift of code edges based on the optimal transmission point of a DP-MZM.

To eliminate the time shift of code edges on a single-sideband (SSB) modulation signal transmission in a radio-over-fiber (RoF) system, a new, to the best of our knowledge, SSB modulation scheme based on an optimal transmission point for a double-parallel Mach-Zehnder modulator (DP-MZM) is proposed. The scheme is based on DP-MZM to realize the separation of the carrier and the +1st-order sideband at the optimal transmission point, and the baseband signal modulates the 2.5Gb/s data signal to the +1st-order sideband of the SSB signal; then, the carrier and the +1st-order sideband are transmitted with a carrier-to-sideband ratio of 0dB. Theoretical analysis shows that compared to the traditional SSB-modulated optical millimeter-wave signal generation scheme this scheme completely solves the problem of the time shift of code edges caused by dispersion. The simulation results show that the improved SSB modulation scheme has a Q factor of 23.362, the minimum bit error rate is 4.207×10-127 at 73.453km, and the eye diagram is still very clear. Under the premise of meeting the basic requirements of communications, the maximum communications distance can reach 135km, which is 270% of the transmission distance of a traditional SSB modulation model.Thus, the system performance has been greatly improved.

Intermediate filament proteins are reliable immunohistological biomarkers to help diagnose multiple tissue-specific diseases.

Cytoskeletal networks are proteins that effectively maintain cell integrity and provide mechanical support to cells by actively transmitting mechanical signals. Intermediate filaments, which are from the cytoskeleton family and are 10 nanometres in diameter, are unlike actin and microtubules, which are highly dynamic cytoskeletal elements. Intermediate filaments are flexible at low strain, harden at high strain and resist breaking. For this reason, these filaments fulfil structural functions by providing mechanical support to the cells through their different strain-hardening properties. Intermediate filaments are suitable in that cells both cope with mechanical forces and modulate signal transmission. These filaments are composed of fibrous proteins that exhibit a central α-helical rod domain with a conserved substructure. Intermediate filament proteins are divided into six groups. Type I and type II include acidic and basic keratins, type III, vimentin, desmin, peripheralin and glial fibrillary acidic protein (GFAP), respectively. Type IV intermediate filament group includes neurofilament proteins and a fourth neurofilament subunit, α-internexin proteins. Type V consists of lamins located in the nucleus, and the type VI group consists of lens-specific intermediate filaments, CP49/phakinin and filen. Intermediate filament proteins show specific immunoreactivity in differentiating cells and mature cells of various types. Various carcinomas such as colorectal, urothelial and ovarian, diseases such as chronic pancreatitis, cirrhosis, hepatitis and cataract have been associated with intermediate filaments. Accordingly, this section reviews available immunohistochemical antibodies to intermediate filament proteins. Identification of intermediate filament proteins by methodological methods may contribute to the understanding of complex diseases.

Silica micro-rod resonator-based Kerr frequency comb for high-speed short-reach optical interconnects.

Conventional data center interconnects rely on power-hungry arrays of discrete wavelength laser sources. However, growing bandwidth demand severely challenges ensuring the power and spectral efficiency toward which data center interconnects tend to strive. Kerr frequency combs based on silica microresonators can replace multiple laser arrays, easing the pressure on data center interconnect infrastructure. Therefore, we experimentally demonstrate a bit rate of up to 100 Gbps/λ employing 4-level pulse amplitude modulated signal transmission over a 2 km long short-reach optical interconnect that can be considered a record using any Kerr frequency comb light source, specifically based on a silica micro-rod. In addition, data transmission using the non-return to zero on-off keying modulation format is demonstrated to achieve 60 Gbps/λ. The silica micro-rod resonator-based Kerr frequency comb light source generates an optical frequency comb in the optical C-band with 90 GHz spacing between optical carriers. Data transmission is supported by frequency domain pre-equalization techniques to compensate amplitude-frequency distortions and limited bandwidths of electrical system components. Additionally, achievable results are enhanced with offline digital signal processing, implementing post-equalization using feed-forward and feedback taps.

Performance Analysis of a Reconfigurable-Intelligent-Surfaces-Assisted V2V Communication System

Novel reconfigurable Intelligent Surfaces (RISs) area technology can improve the communication performance by changing the wireless transmission environment. Introducing RIS technology into Vehicle-to-Vehicle (V2V) communication environments can enhance the communication reliability by creating Line-of-Sight (LoS) communication links, thereby effectively improving the communication performance. However, in RIS-assisted V2V large-scale communication networks, the stochasticity of network nodes and random interference can impact performance. In this article, we examine the outage communication transmission performance of an RIS-assisted V2V communication network. We select the signal transmission mode based on the obstacle presence between vehicles and use the stochastic geometry theory to calculate the probabilities of the two modes: direct mode and RIS-assisted mode. By deriving the communication distance distribution and the aggregate interference distribution, we evaluate V2V communication in the direct mode to assess its transmission performance in two scenarios and obtain the overall outage probability. The numerical results demonstrate a better performance in RIS-assisted V2V networks, with an improved optimal phase shift scheme over that of the original V2V network. Monte Carlo simulation validated our analytical findings.

Remote mmW photonic local oscillator delivery for uplink down-conversion in DML-based optical hybrid C-RAN fronthaul

In this work, we propose and demonstrate the remote delivery of a photonically generated local oscillator (LO) signal for uplink down-conversion in photonically generated millimeter-wave (mmW) signals over duplex centralized radio access network fronthaul. The technique, based on carrier-suppressed external modulation in a single Mach–Zehnder modulator, is employed for generating the mmW signals, which are distributed over hybrid optical links composed of fiber and free-space optics (FSO) prior to the radio wireless link at 42 GHz, and also for the uplink (UL) LO generation enabling the 38 GHz UL signal down-conversion. A 5G new radio (NR) quadrature phase-shift keying (QPSK) and 64-quadrature amplitude modulation (QAM) signal transmission is successfully demonstrated using low-frequency directly modulated lasers for both the downlink and the UL mmW transmission, and thus a low-cost and simple intermediate frequency over fiber and FSO UL deployment are presented. The lowest achieved error vector magnitudes with the 5G NR signals at 100 MHz bandwidth in the proposed mmW UL schemes, including 10 km of optical fiber and a 1.1 m long FSO link, are 5.8% and 6% for QPSK and 64-QAM, respectively.

C-band 100-GBaud PS-PAM-4 transmission over 50-km SSMF enabled by FIR-filter-based pre-electronic dispersion compensation.

Chromatic dispersion (CD) is always an obstacle to C-band high-speed intensity modulation and direct detection (IM/DD) transmissions, especially with a fiber reach of > 20 km. To reach beyond net-100-Gb/s IM/DD transmission over 50-km standard single mode fiber (SSMF), we for the first time present a CD-aware probabilistically shaped four-ary pulse amplitude modulation (PS-PAM-4) signal transmission scheme with a FIR-filter-based pre-electronic dispersion compensation (FIR-EDC) for C-band IM/DD transmission system. With the help of the FIR-EDC at the transmitter, 100-GBaud PS-PAM-4 signal transmission at 150-Gb/s line rate and 115.2-Gb/s net rate over 50-km SSMF is realized with only feed-forward equalization (FFE) at the receiver side. The superiority of the CD-aware PS-PAM-4 signal transmission scheme over other benchmark schemes has been successfully verified by experiments. Experimental results show that 24.5% improvement of system capacity is obtained by the FIR-EDC-based PS-PAM-4 signal transmission scheme in comparison to the FIR-EDC-based on-off keying (OOK) signal transmission scheme. Compared with the FIR-EDC-based uniform PAM-4 signal transmission scheme or the PS-PAM-4 signal transmission scheme without EDC, the capacity improvement obtained by the FIR-EDC-based PS-PAM-4 signal transmission scheme becomes more profound. The results show the potential and feasibility of such CD-aware PS-PAM-4 signal transmission scheme applied in CD-constrained IM/DD datacenter interconnects.

Neurobiológia chorôb pečene

he nervous system is an important factor that participates in the adaptive and compensatory reactions of the body, not only in physiological but also in pathological processes. Alterations in the activity of the nervous system may contribute to the development of somatic diseases and may also influence their progression. Experimental and clinical studies have shown that the nervous system also plays a role in liver diseases. Depending on the disease and on the mechanisms and pathways, the nervous system can play a positive as well as a negative role in liver diseases. The aim of this review is to describe the mechanisms and pathways through which the nervous system affects the development and progression of the most common liver diseases, such as alcoholic liver damage, non-alcoholic fatty liver disease, cholestatic liver diseases, hepatitis, cirrhosis, and hepatocellular carcinoma. In addition, we also describe the possible therapeutic consequences based on the modulation of signal transmission between the nervous system and the liver. Keywords alcoholic liver damage, autonomic nervous system, cirrhosis, chronic hepatitis, hepatocellular carcinoma, cholestatic liver diseases, neurobiology, fatty liver disease

2.4-Tb/s/λ*km fundamental mode transmission over OM2 fiber employing Kramers-Kronig receiver.

We propose a digital-carrier Kramers-Kronig (DC-KK) scheme based high-speed multimode fiber short-reach optical interconnect system with fundamental mode transmission. After optimization of the parameters, including the roll-off factor of the root-raised-cosine (RRC) filter, and the guard interval (GI) between signal and carrier tone, as well as the carrier signal power ratio (CSPR), 200-Gb/s 32-quadrature amplitude modulation (32QAM) signal transmission over 12-km OM2 fiber has been experimentally demonstrated with a bit error ratio (BER) below the soft-decision forward error correction (SD-FEC) threshold of 4 × 10-2. To the best of our knowledge, this is the highest experimental record of single lambda bitrate-distance-product (SLBDP) achieved by direct-detection (DD)-based transmission over a standard multimode fiber (MMF). The proposed scheme has potential to improve the system performance without replacing massive deployed legacy MMFs for future large-capacity data center interconnects (DCIs).

An approach for linear optical phase demodulation using a single photodetector.

In this paper, we propose and experimentally verify a phase-modulated radio-over-fiber (RoF) link capable of transmitting the radio frequency (RF) signal linearly. By executing the Kramers-Kronig (KK) algorithm at the receiver, the proposed link can accomplish linear optical phase demodulation with a single photodetector rather than a coherent receiver. In the 16-quadrature amplitude modulation (16-QAM) and 64-QAM microwave vector signal transmission experiments, measured error vector magnitudes (EVMs) are 4.14% and 4.38%, respectively, after 25-km fiber transmission, and the measured spurious-free dynamic range (SFDR) is 114.5 dB·Hz2/3, which shows a good performance in linearity.

Steric Communication between Dynamic Components on DNA Nanodevices.

Biomolecular nanotechnology has helped emulate basic robotic capabilities such as defined motion, sensing, and actuation in synthetic nanoscale systems. DNA origami is an attractive approach for nanorobotics, as it enables creation of devices with complex geometry, programmed motion, rapid actuation, force application, and various kinds of sensing modalities. Advanced robotic functions like feedback control, autonomy, or programmed routines also require the ability to transmit signals among subcomponents. Prior work in DNA nanotechnology has established approaches for signal transmission, for example through diffusing strands or structurally coupled motions. However, soluble communication is often slow and structural coupling of motions can limit the function of individual components, for example to respond to the environment. Here, we introduce an approach inspired by protein allostery to transmit signals between two distal dynamic components through steric interactions. These components undergo separate thermal fluctuations where certain conformations of one arm will sterically occlude conformations of the distal arm. We implement this approach in a DNA origami device consisting of two stiff arms each connected to a base platform via a flexible hinge joint. We demonstrate the ability for one arm to sterically regulate both the range of motion and the conformational state (latched or freely fluctuating) of the distal arm, results that are quantitatively captured by mesoscopic simulations using experimentally informed energy landscapes for hinge-angle fluctuations. We further demonstrate the ability to modulate signal transmission by mechanically tuning the range of thermal fluctuations and controlling the conformational states of the arms. Our results establish a communication mechanism well-suited to transmit signals between thermally fluctuating dynamic components and provide a path to transmitting signals where the input is a dynamic response to parameters like force or solution conditions.

A Review of Two Types of New Key Technologies of 6G

The increasing need of future 6G wireless communication of higher transmission rate, larger network capacity, higher energy efficiency has been calling for the development of new key technologies. Among them, the two most popular and promising technologies are new spectrum access technology and efficient wireless transmission technology. New spectrum access technology intends to achieve the utilization of more available spectrum resources with higher frequency and wider bandwidth so that it can highly improve the data transfer rate and expand the network capacity. It includes Terahertz communication technology and visible light communication technology. Efficient Wireless Transmission technology aims to make new breakthroughs in traditional signal transmission mode and achieve larger channel capacity so that network coverage and security can be improved, and signal transmission loss can be decreased. It contains IRS technology and Spatial multiplexing technology. Properties of each technology, such as principles, advantages, application scenarios, are discussed in this paper. In chapter 2, new spectrum access technology is introduced, and efficient wireless transmission technology is introduced in chapter 3.